Centrifugal pump start method, centrifugal pump start note
Before the start of the centrifugal pump is ready, open the diversion gate, so that the front tank to the design level, you can start the pump.
Centrifugal pump start Note:
When starting the centrifugal pump, the staff will have to leave the unit at a certain distance. For centrifugal pumps and volute mixed flow pump, usually closed valve start, standby group speed reaches the rated value, you can open the vacuum gauge and the pressure gauge on the valve, this time, the pressure gauge reading should rise to the pump flow is zero When the maximum value, then you can gradually open the pressure on the pipeline valve. If there is no exception, then the vacuum gauge reading will gradually increase, the pressure gauge reading should be gradually decreased, the motor ammeter reading should be gradually increased. Start the work until the valve is fully open, that is completed. In the closed valve should be noted that the valve running time should generally not exceed 5 minutes, such as the time is too long, the pump liquid heat, may cause accidents.
For self-priming pumps, vertical axial flow pump and guide vane mixed flow pump, usually open the valve. While filling the rubber bearing, while the motor can start, until the speed reaches the rated value, stop filling water, that is, to complete the start work.
2017年2月16日星期四
Demolition of Double - suction Centrifugal Pump
Double suction pump disassembly method, centrifugal pump disassembly method
Remove the double suction centrifugal pump do not need to break into the outlet pipe and motor, as long as the pump cover can be opened.
(1) Removal of the centrifugal pump pump cover
First loosen the packing glands at both ends of the pump cover, pull the packing glands on both sides, then release the nuts on the pump cover and remove the centrifugal pump cover.
(2) disassembly of centrifugal pump coupling
Coupling disassembly can be carried out before and after removal of the pump cover.
(3) Removal of the centrifugal pump rotor
Remove the bearings at both ends of the pump shaft and the bearing cap at both ends, remove the two bearing bodies, and release the two round nuts pressed against the bearing with a special tool. With a pull bearing at both ends of the rolling bearing. After removing the rolling bearing, remove the bearing cover, retaining ring, packing gland, water seal ring, packing sleeve and other parts from the pump shaft, and then remove the sleeve. Finally press the impeller with a press. If there is no press, you can put the impeller flat pad, with a wooden hammer to the impeller back.
Remove the double suction centrifugal pump do not need to break into the outlet pipe and motor, as long as the pump cover can be opened.
(1) Removal of the centrifugal pump pump cover
First loosen the packing glands at both ends of the pump cover, pull the packing glands on both sides, then release the nuts on the pump cover and remove the centrifugal pump cover.
(2) disassembly of centrifugal pump coupling
Coupling disassembly can be carried out before and after removal of the pump cover.
(3) Removal of the centrifugal pump rotor
Remove the bearings at both ends of the pump shaft and the bearing cap at both ends, remove the two bearing bodies, and release the two round nuts pressed against the bearing with a special tool. With a pull bearing at both ends of the rolling bearing. After removing the rolling bearing, remove the bearing cover, retaining ring, packing gland, water seal ring, packing sleeve and other parts from the pump shaft, and then remove the sleeve. Finally press the impeller with a press. If there is no press, you can put the impeller flat pad, with a wooden hammer to the impeller back.
2017年2月15日星期三
How does single-stage single-suction centrifugal pumps work?
Single-stage single-suction centrifugal pump from the impeller, pump shaft, pump and other components. Impeller center facing the inlet, water, water pipes, respectively, and centrifugal pump water, outlet connection.
How does the centrifugal pump work: the water centrifugal pump should be filled with water before starting. When the power machine through the pump shaft to drive the high-speed rotation of the impeller, the impeller in the water due to the role of inertial centrifugal force, from the impeller center to the outer edge of the impeller, and pooled into the pump body, the potential energy and kinetic energy in the pump body was directed to the outlet , Along the water pipeline to the outlet. At the same time, the impeller inlet to produce a vacuum, and the role of the water in the inlet basin pressure for the atmospheric pressure, the water in the pool will be under the pressure difference between the role, through the inlet pipe into the impeller. Impeller kept spinning, the water is constantly being thrown and inhaled, centrifugal pump is the work of this.
How does the centrifugal pump work: the water centrifugal pump should be filled with water before starting. When the power machine through the pump shaft to drive the high-speed rotation of the impeller, the impeller in the water due to the role of inertial centrifugal force, from the impeller center to the outer edge of the impeller, and pooled into the pump body, the potential energy and kinetic energy in the pump body was directed to the outlet , Along the water pipeline to the outlet. At the same time, the impeller inlet to produce a vacuum, and the role of the water in the inlet basin pressure for the atmospheric pressure, the water in the pool will be under the pressure difference between the role, through the inlet pipe into the impeller. Impeller kept spinning, the water is constantly being thrown and inhaled, centrifugal pump is the work of this.
The main advantages and disadvantages of centrifugal pumps
The main advantages of centrifugal pumps
A. Centrifugal pump flow range is very large, commonly used in the 5 ~ 2000m. / H, the largest foreign reach 54500m3 / h. Another flow and pressure are smooth, no fluctuations.
B. Centrifugal pump speed is high, can be directly connected with the motor and steam turbine, transmission mechanism is simple and compact.
C. Easy to operate, easy to adjust and repair, and easy to automate and remote operation.
D. Centrifugal pump compared with the same indicators of the reciprocating pump, the structure is simple and compact, small size, light weight, fewer parts, easy manufacturing, low cost, and small footprint, so its equipment and repair costs are relatively low.
Centrifugal pumps have major drawbacks:
A, in general, the centrifugal pump before starting the first pump or water ring vacuum pump to pump out the air. Self-priming centrifugal pump before the start, although there is no need to pump, but there are limitations on the use. B, liquid viscosity on the performance of a greater impact on the pump. When the liquid viscosity increases, the pump flow, head, suction and efficiency will be significantly reduced. C, centrifugal pump in the case of small flow of high-lift applications, subject to certain restrictions. Because the small centrifugal pump pump flow channel is very narrow, manufacturing difficulties, while the efficiency is very low. Although the centrifugal pump has some shortcomings, but the advantages of more, in many cases, centrifugal pumps are replaced by the reciprocating pump, so the centrifugal pump has been widely used.
A. Centrifugal pump flow range is very large, commonly used in the 5 ~ 2000m. / H, the largest foreign reach 54500m3 / h. Another flow and pressure are smooth, no fluctuations.
B. Centrifugal pump speed is high, can be directly connected with the motor and steam turbine, transmission mechanism is simple and compact.
C. Easy to operate, easy to adjust and repair, and easy to automate and remote operation.
D. Centrifugal pump compared with the same indicators of the reciprocating pump, the structure is simple and compact, small size, light weight, fewer parts, easy manufacturing, low cost, and small footprint, so its equipment and repair costs are relatively low.
Centrifugal pumps have major drawbacks:
A, in general, the centrifugal pump before starting the first pump or water ring vacuum pump to pump out the air. Self-priming centrifugal pump before the start, although there is no need to pump, but there are limitations on the use. B, liquid viscosity on the performance of a greater impact on the pump. When the liquid viscosity increases, the pump flow, head, suction and efficiency will be significantly reduced. C, centrifugal pump in the case of small flow of high-lift applications, subject to certain restrictions. Because the small centrifugal pump pump flow channel is very narrow, manufacturing difficulties, while the efficiency is very low. Although the centrifugal pump has some shortcomings, but the advantages of more, in many cases, centrifugal pumps are replaced by the reciprocating pump, so the centrifugal pump has been widely used.
What is the reason for the centrifugal pump trip
In general, the main reasons for the pump trip are: (1), the use of centrifugal pump head less than the head of the pump too much lead to excessive flow after the current rise and over current, the solution control the outlet valve opening flow control and the current Down to allow the current range, or change the impeller diameter to reduce the pump head. (2), the pump motor damps lead to excessive current. (3), pump motor quality problems. (4), the pump voltage is unstable. (5), pump control cabinet system problems.
1: centrifugal pump trip fault phenomenon
After the unit has been put into operation, the centrifugal pump will work for a period of time after a closing trip. After excluding the switch mechanism failure, according to the conventional method to check the cable, the secondary circuit wiring and the relay and its settings are normal, start again and often successful. After the suspected dcs system caused by a soft fault, but changed in the control panel operation, this phenomenon will still occur.
2: Centrifuge the cause of the pump trip
In order to find out the cause of this phenomenon, observe the change of the meter in the process of closing the switch to confirm what causes it to trip.
Test which the voltmeter monitor microcomputer trip circuit, mA table monitor differential relay 1cj, 2cj action, ammeter monitoring thermal protection circuit. After a good meter, start the pump, after a period of time test, and finally once a pump to start the trip, while observing the milliphe pointer deflection of the pointer, the other monitoring table does not respond, the new put on xjl -0025/31-type integrated block signal relay 1xj also action out of the card, indicating that the differential protection action caused by tripping.
3: Centrifugal Pump Trip Root Cause Analysis
Differential protection action, first suspected of being protected within the equipment failure. Through routine inspection, centrifugal pump motor and its cable normal, differential relay calibration is normal, the current transformer polarity connection is correct. After troubleshooting the cause of the equipment failure and wiring errors, the differential protection operates during the motor start, indicating that the differential current in the differential circuit exceeds the differential relay setting during this process.
Under normal circumstances caused by differential circuit differential current causes there are two main points: First, the motor on both sides of the current transformer variable ratio error is different from the existence of a very small difference current, the current difference is less than the motor rated current id 5% The Second, the difference between the secondary load on both sides of the current transformer will also cause the difference between the variable ratio, so there is a differential current. The difference between the current transformer load in the differential protection circuit of the feed pump motor is only about 50 m in the length of the secondary cable, and the power consumption of the differential relay is not more than 3 va at the rated current, and the secondary load is not weight. Inspection found that the pump head motor differential protection with the first and second side of the current transformer models are lmzbj-10, b class 15 times the rated current, variable ratio 600/5, capacity 40 va, fully meet the secondary load requirements.
The above analysis is based on the normal operation of the conditions, the motor starts, the situation is different. Motor current is very large start, both ends of the current transformer may be saturated, this time due to the current transformer magnetization characteristics are inconsistent, the secondary difference current may be great. According to the sub-relay factory lcd-12 differential relay set instructions, the relay action current setting value izd = △ i1 × kk × in / n = 0.06 × 3 × 356/120 = 0.534a (where: △ i1- First and the end of the current transformer normal operation of the maximum error, 0.04 ~ 0.06; kk-reliable coefficient, 2 ~ 3; in-motor rated current; n-current transformer ratio). Should be set at 1.0a position. In the case of the use of b-class transformer, the differential relay operating current is set at 1.5a and the braking coefficient is 0.4, the differential protection is occasionally operated at the time of starting the motor due to the saturation characteristic of the b-type current transformer Lower, low resistance to saturation, can not meet the requirements of differential relays. Usually require differential protection circuit current transformer using d-class, d-class transformer saturation point higher, not so easy to saturation, can reduce the motor when the differential flow through the differential circuit current. In the replacement of the d-level current transformer, while the differential relay operating current set at 1.0a, the braking coefficient of 0.4, there has been no switch off the trip that is the fault.
1: centrifugal pump trip fault phenomenon
After the unit has been put into operation, the centrifugal pump will work for a period of time after a closing trip. After excluding the switch mechanism failure, according to the conventional method to check the cable, the secondary circuit wiring and the relay and its settings are normal, start again and often successful. After the suspected dcs system caused by a soft fault, but changed in the control panel operation, this phenomenon will still occur.
2: Centrifuge the cause of the pump trip
In order to find out the cause of this phenomenon, observe the change of the meter in the process of closing the switch to confirm what causes it to trip.
Test which the voltmeter monitor microcomputer trip circuit, mA table monitor differential relay 1cj, 2cj action, ammeter monitoring thermal protection circuit. After a good meter, start the pump, after a period of time test, and finally once a pump to start the trip, while observing the milliphe pointer deflection of the pointer, the other monitoring table does not respond, the new put on xjl -0025/31-type integrated block signal relay 1xj also action out of the card, indicating that the differential protection action caused by tripping.
3: Centrifugal Pump Trip Root Cause Analysis
Differential protection action, first suspected of being protected within the equipment failure. Through routine inspection, centrifugal pump motor and its cable normal, differential relay calibration is normal, the current transformer polarity connection is correct. After troubleshooting the cause of the equipment failure and wiring errors, the differential protection operates during the motor start, indicating that the differential current in the differential circuit exceeds the differential relay setting during this process.
Under normal circumstances caused by differential circuit differential current causes there are two main points: First, the motor on both sides of the current transformer variable ratio error is different from the existence of a very small difference current, the current difference is less than the motor rated current id 5% The Second, the difference between the secondary load on both sides of the current transformer will also cause the difference between the variable ratio, so there is a differential current. The difference between the current transformer load in the differential protection circuit of the feed pump motor is only about 50 m in the length of the secondary cable, and the power consumption of the differential relay is not more than 3 va at the rated current, and the secondary load is not weight. Inspection found that the pump head motor differential protection with the first and second side of the current transformer models are lmzbj-10, b class 15 times the rated current, variable ratio 600/5, capacity 40 va, fully meet the secondary load requirements.
The above analysis is based on the normal operation of the conditions, the motor starts, the situation is different. Motor current is very large start, both ends of the current transformer may be saturated, this time due to the current transformer magnetization characteristics are inconsistent, the secondary difference current may be great. According to the sub-relay factory lcd-12 differential relay set instructions, the relay action current setting value izd = △ i1 × kk × in / n = 0.06 × 3 × 356/120 = 0.534a (where: △ i1- First and the end of the current transformer normal operation of the maximum error, 0.04 ~ 0.06; kk-reliable coefficient, 2 ~ 3; in-motor rated current; n-current transformer ratio). Should be set at 1.0a position. In the case of the use of b-class transformer, the differential relay operating current is set at 1.5a and the braking coefficient is 0.4, the differential protection is occasionally operated at the time of starting the motor due to the saturation characteristic of the b-type current transformer Lower, low resistance to saturation, can not meet the requirements of differential relays. Usually require differential protection circuit current transformer using d-class, d-class transformer saturation point higher, not so easy to saturation, can reduce the motor when the differential flow through the differential circuit current. In the replacement of the d-level current transformer, while the differential relay operating current set at 1.0a, the braking coefficient of 0.4, there has been no switch off the trip that is the fault.
2017年2月14日星期二
ISG pipe pump whether there is suction
ISG pipeline pump is installed in the pipeline on an increase in the pump, is also a kind of centrifugal pump, usually in the pipeline water but the pressure is not enough to transport water to a higher destination, the use of ISG pipeline The pump is pressurized to reach the destination.
Is the ISG pipeline pump sucking?
Of course, but please do not misunderstand the two concepts of suction and self-absorption.
Self-priming refers to the process of pumping water from the lower to the pump chamber in the absence of water (empty tube) in the inlet line (the verb, self-absorption is an action and a process), only the self-priming pump Only with self-absorption function.
Suction - refers to the distance in the inlet pipe, but the import without positive pressure, the pump in the work of its imports can absorb much depth within the distance (quantifier, in length). All centrifugal pumps actually have suction, but the length of different, in short, the higher head, suction will be correspondingly higher, but no specific conversion standards. In general, the suction line of the ISG pipeline pump is not more than 4 meters without preconditioning without any auxiliary equipment.
After installing the siphon device, the ISG pipeline pump can actually operate as a self-priming pump, giving the self-priming capability of the ISG pipeline pump by integrating the siphon. But there is self-absorption pump, who will be so superfluous it
Is the ISG pipeline pump sucking?
Of course, but please do not misunderstand the two concepts of suction and self-absorption.
Self-priming refers to the process of pumping water from the lower to the pump chamber in the absence of water (empty tube) in the inlet line (the verb, self-absorption is an action and a process), only the self-priming pump Only with self-absorption function.
Suction - refers to the distance in the inlet pipe, but the import without positive pressure, the pump in the work of its imports can absorb much depth within the distance (quantifier, in length). All centrifugal pumps actually have suction, but the length of different, in short, the higher head, suction will be correspondingly higher, but no specific conversion standards. In general, the suction line of the ISG pipeline pump is not more than 4 meters without preconditioning without any auxiliary equipment.
After installing the siphon device, the ISG pipeline pump can actually operate as a self-priming pump, giving the self-priming capability of the ISG pipeline pump by integrating the siphon. But there is self-absorption pump, who will be so superfluous it
The basic principle of ISG pipeline pump
ISG pipeline pump for the vertical structure, import and export caliber the same, and is located in a unified center line, like the valve can be installed in the same pipe, compact appearance, small footprint, low construction investment, such as with a protective cover Can be placed outdoors.
ISG pipeline pump impeller directly on the motor's elongated shaft, axial size is short, compact, pump and motor bearing configuration is reasonable, can effectively balance the pump running radial and axial load, thus ensuring the pump running smoothly , Vibration noise is very low.
ISG pipe pump shaft seal using mechanical seal or mechanical seal combination, the use of imported titanium seal ring, medium high temperature mechanical seal and the use of carbide material, wear-resistant seal, can effectively increase the mechanical seal life.
ISG pipeline pump installation easy maintenance, no need to dismantle the pipeline system, as long as the removal of the pump seat nut can take out all the rotor parts.
ISG pipeline pump can be used according to the requirements of the flow and head of the need to use the pump string, parallel operation.
ISG pipeline pump can be used in accordance with the requirements of the pipeline layout of the pump vertical and horizontal installation.
ISG pipeline pump works: the pump is filled with liquid in the case, the impeller rotation produces centrifugal force, the impeller channel in the centrifugal force of the liquid thrown to the periphery, into the pump shell, the impeller center to form a vacuum, the liquid in the atmosphere Under the action of pressure, by the import pipeline into the impeller. So that the liquid is constantly being sucked and hit. The liquid that gets energy in the impeller has a large kinetic energy when it flows out of the impeller, which is collected in the helical pump housing and becomes kinetic energy in the later diffuser.
ISG pipeline pump impeller directly on the motor's elongated shaft, axial size is short, compact, pump and motor bearing configuration is reasonable, can effectively balance the pump running radial and axial load, thus ensuring the pump running smoothly , Vibration noise is very low.
ISG pipe pump shaft seal using mechanical seal or mechanical seal combination, the use of imported titanium seal ring, medium high temperature mechanical seal and the use of carbide material, wear-resistant seal, can effectively increase the mechanical seal life.
ISG pipeline pump installation easy maintenance, no need to dismantle the pipeline system, as long as the removal of the pump seat nut can take out all the rotor parts.
ISG pipeline pump can be used according to the requirements of the flow and head of the need to use the pump string, parallel operation.
ISG pipeline pump can be used in accordance with the requirements of the pipeline layout of the pump vertical and horizontal installation.
ISG pipeline pump works: the pump is filled with liquid in the case, the impeller rotation produces centrifugal force, the impeller channel in the centrifugal force of the liquid thrown to the periphery, into the pump shell, the impeller center to form a vacuum, the liquid in the atmosphere Under the action of pressure, by the import pipeline into the impeller. So that the liquid is constantly being sucked and hit. The liquid that gets energy in the impeller has a large kinetic energy when it flows out of the impeller, which is collected in the helical pump housing and becomes kinetic energy in the later diffuser.
Trouble Cause and Treatment of Centrifugal Pump
In the water supply system, the pump is in regular operation, often due to various failures so that the pump can not work properly. Centrifugal pump common faults, the causes and treatment methods:
Water pump is not on the water
(1) When the pump suction pipe due to the slope of the tube there is air and has formed a gas plug, so that the pump can not continue to absorb water caused by water pump. When there is inverted slope, should adjust the slope, and timely rejection of the pump and the suction pipe of the air.
(2) lack of water at the end of the valve or damage, so that the water pipe is less than water, or the end of the valve and the suction port is blocked by debris, so that the end of the valve closed lax. When the above-mentioned fault should be confirmed after the timely cleaning of dirt, maintenance of the end of the valve, should be replaced when damaged.
(3) Bottom valve submerged depth is not enough to cause the pump is not on the water, should increase the depth of the suction pipe immersed in the water.
(4) the pool (water tank) in the water level is too low will make the pump is not on the water, this time should check the water system in the water, water pressure is seriously inadequate; float valve, liquid level control valve is fault. Should be timely adjust the replenishment time (such as the use of low water at night when the water), repair or replacement of the failure of the inlet valve.
2. Pump water discharge in addition to check the submerged depth of the suction pipe, suction pipe down the gas and other reasons, but also need to check the pump impeller seal ring is damaged and timely replacement.
3. Water pump bearing overheating In the pump operation, the bearing temperature should not exceed 60 ℃, when the bearing lack of oil or pump and motor shaft is not the heart, bearing clearance is too small, the packing pressure too tight, can cause the bearing overheating. At this point, should adjust the concentricity, refueling, adjust the packing gland tightness.
4. Pump running vibration and noise is too large.
Water pump concentricity deviation is too large will produce greater vibration, followed by check the anchor bolts, the base bolts are tightened without loosening. Noise reduction or vibration isolation devices shall be added to buildings requiring strict control of noise and vibration.
When the suction pipe depth is too large, the water level is too low, but also make the pump cavitation phenomenon and increase the pump noise.
Water pump is not on the water
(1) When the pump suction pipe due to the slope of the tube there is air and has formed a gas plug, so that the pump can not continue to absorb water caused by water pump. When there is inverted slope, should adjust the slope, and timely rejection of the pump and the suction pipe of the air.
(2) lack of water at the end of the valve or damage, so that the water pipe is less than water, or the end of the valve and the suction port is blocked by debris, so that the end of the valve closed lax. When the above-mentioned fault should be confirmed after the timely cleaning of dirt, maintenance of the end of the valve, should be replaced when damaged.
(3) Bottom valve submerged depth is not enough to cause the pump is not on the water, should increase the depth of the suction pipe immersed in the water.
(4) the pool (water tank) in the water level is too low will make the pump is not on the water, this time should check the water system in the water, water pressure is seriously inadequate; float valve, liquid level control valve is fault. Should be timely adjust the replenishment time (such as the use of low water at night when the water), repair or replacement of the failure of the inlet valve.
2. Pump water discharge in addition to check the submerged depth of the suction pipe, suction pipe down the gas and other reasons, but also need to check the pump impeller seal ring is damaged and timely replacement.
3. Water pump bearing overheating In the pump operation, the bearing temperature should not exceed 60 ℃, when the bearing lack of oil or pump and motor shaft is not the heart, bearing clearance is too small, the packing pressure too tight, can cause the bearing overheating. At this point, should adjust the concentricity, refueling, adjust the packing gland tightness.
4. Pump running vibration and noise is too large.
Water pump concentricity deviation is too large will produce greater vibration, followed by check the anchor bolts, the base bolts are tightened without loosening. Noise reduction or vibration isolation devices shall be added to buildings requiring strict control of noise and vibration.
When the suction pipe depth is too large, the water level is too low, but also make the pump cavitation phenomenon and increase the pump noise.
Assembly method of centrifugal pump impeller
Centrifugal pump impeller bore and journal between the gap with the gap between the value of 0.1 ~ 0.15 mm. When the impeller is to be fitted, the impeller shall be slid on the journal without swinging. When the gap is too small, you can use the file cutting method to reduce the size of the shaft diameter, but also in the lathe on the impeller of the hole car larger, in order to ensure that the gap should be. When the gap is too large, replace the new impeller so that the clearance accuracy is not affected by the clearance.
When assembling the centrifugal pump impeller to the shoulder, the M should be facing the pump body out of the M pipe, should not produce axial displacement. No friction between the impeller back and the pump body, but the axial gap between them can not be too large. If the axial clearance is large here, the amount of leakage of the axial seal is increased. In order to reduce the axial clearance here, the thickness of the gasket on the front and rear axle cover can be readjusted, that is, the thickness of the gasket of the front bearing of the pump to the M side is thinned and will be close to the coupling The thickness of the rear bearing gland is thickened. In adjusting the thickness of the bearing gland gasket, the total weight of the front and rear bearing glands should be equal to the total thickness of the original assembly, ie the thickness of the front bearing gland pad minus the thickness of the rear bearing gland pad To be equal. While adjusting the gasket, tap the pump shaft slightly rearward to move it a very small distance, and then press the rear cover, thus reducing the axial clearance between the impeller's back and the pump The If the back of the impeller and the pump body is too small between the friction between the friction, the adjustment of the gasket is the same as above, but the rear bearing gland pad thinner, the front bearing gland pad thickening, and the pump shaft Move forward a little distance can be.
When assembling the centrifugal pump impeller to the shoulder, the M should be facing the pump body out of the M pipe, should not produce axial displacement. No friction between the impeller back and the pump body, but the axial gap between them can not be too large. If the axial clearance is large here, the amount of leakage of the axial seal is increased. In order to reduce the axial clearance here, the thickness of the gasket on the front and rear axle cover can be readjusted, that is, the thickness of the gasket of the front bearing of the pump to the M side is thinned and will be close to the coupling The thickness of the rear bearing gland is thickened. In adjusting the thickness of the bearing gland gasket, the total weight of the front and rear bearing glands should be equal to the total thickness of the original assembly, ie the thickness of the front bearing gland pad minus the thickness of the rear bearing gland pad To be equal. While adjusting the gasket, tap the pump shaft slightly rearward to move it a very small distance, and then press the rear cover, thus reducing the axial clearance between the impeller's back and the pump The If the back of the impeller and the pump body is too small between the friction between the friction, the adjustment of the gasket is the same as above, but the rear bearing gland pad thinner, the front bearing gland pad thickening, and the pump shaft Move forward a little distance can be.
2017年2月13日星期一
How to carry out the maintenance of vertical multi-stage centrifugal pump
Maintenance method for vertical multi-stage centrifugal pump:
1. Vertical multistage centrifugal pump repair, motor control switch must be in the "off" position and hanging tablets so as not to cause physical damage. In multistage pump disassembly should be in the parts together mark, for the installation can be carried out smoothly; multistage pump to remove the small parts and fasteners with box installed, mark, indicate the premises; multistage pump removed parts clean, coated with anti rust oil, paint surface if there is corrosion, to the eradication of the corrosion and repainted; horizontal multistage centrifugal pump "O" shape ring, a packing and corrosion of fastening pieces can not be reused for the parts.
2. The vertical multistage centrifugal pump maintenance, the first pump have been removed from the tank, dismantling the motor and a machine base, remove the lower pump shell, knock down the shaft and impeller (pay attention to the pump shaft anticorrosion coating) release bearing sit six hexagon bolt, then is a pump shaft and a bearing assembly together can be pulled out for maintenance.
3. Rotating coupling and just down into the belt, vertical multistage centrifugal pump maintenance and replacement of wearing parts after re assembly, the bearing seat, a bearing installed in the pump shaft upper part of the sealed bearing cover installed coupling and tight and round nut, correction of pump shaft bending, the bearing of the pump in the pump body and the bearing seat is arranged in the middle seat, adjustable impeller and pump shell gap, the impeller and the shaft and impeller cap together with phenolic mastic dip in the pump shaft, such as phenolic mastic fully cured, the pump cover installed and assembled by hand in a pump shaft is normal. Such as the replacement of bearings and pump shaft, the first to open the pump shaft and the shaft coupling, loosen the upper and lower bearing cover 12 screws, the bearing can be made up to play.
4. In the maintenance of vertical multi-stage centrifugal pump for two periods, one is running, one is when the.
1). The operation of the multi-stage pump multistage pump packing leakage; multistage pump lubrication pressure; multistage pump lubricating oil level and bearing temperature; do a good job running log, such as horizontal multistage centrifugal pump fault should be recorded in detail.
2). Multi-stage pump stop. Replace the old vertical multistage centrifugal pump packing; replacement of vertical multistage centrifugal pump oil (pump thrust bearing box); monthly water to flush the vertical multistage centrifugal pump water guided bearings, time is about 2 minutes; at the same time, turn the pump rotor; check run horizontal multistage centrifugal pump water skiing system, check whether the loosening of the fastener.
Cause and treatment method of high current of centrifugal pump
Cause and treatment method of high current of centrifugal pump
1. Process medium relative density and viscosity index:
Processing method: check the material component to make its viscosity and relative density and design value is in line with the process operator to adjust
2. Electrical failure :
Processing method: check the circuit breaker heater setting value, check the voltage, three-phase current should be balanced, the error is not greater than 3%
3. When the pump starts, the outlet valve is open, the resistance in the outlet pipe is too small :
Processing method: the outlet valve is closed, the pump starts slowly open the outlet valve .
4. Balance tube is not smooth :
Processing method: clear the balance tube
5. Pump assembly is not good, static and dynamic part of the friction or stuck :
Treatment method: to pump the assembly, check the fit clearance, bearing clearance, mechanical seal, and so on, and strictly according to the design requirements to adjust .
2017年2月10日星期五
Series and parallel operation of centrifugal pump
Centrifugal pump in addition to a single independent work, but also can be a few pumps in parallel or in series. Parallel operation of the pump, that is, the inlet and outlet of several pumps are respectively connected in the same suction and discharge piping system. But parallel pump as far as possible not to use the same suction tube, so as not to interfere with each other. Series is the 1 sets of centrifugal pump discharge port received second sets of centrifugal pump suction inlet pipe line.
1. Centrifugal pump parallel operation can increase the flow rate. In the same pipeline system, increased traffic ratio decreases with the increase of the number of parallel pumps.
2. Centrifugal pump in series can improve the head, but to pay attention to the pump in series in tandem pump body strength.
3. It is best to use the same performance of the centrifugal pump in series and parallel.
4. Either in parallel or in series, the working point of the single centrifugal pump should be in the high efficiency zone.
Method for water diversion and exhaust of centrifugal pump
Method for water diversion and exhaust of centrifugal pump
1. In the inlet and outlet valves of water filling. This method is installed in the inlet pipe of a valve, then the water pipe can be filled with water.
2. Hand pressure pump water filling. Some pumps with a hand pump, can also purchase or do small hand pump installation must be installed in the water inlet valve. After the valve is closed, the first small amount of water filled with water for water diversion, and other hand pressure pump water, said the pump has been filled with water, you can start work.
3. The use of vacuum equipment exhaust water filling. Centrifugal pump and vacuum pump exhaust gas is the same reason, so the use of water ring vacuum pump exhaust to reach the role of water filling.
What are the characteristics of corrosion resistant chemical centrifugal pump
1. Corrosion resistance, high temperature resistance, low temperature: chemical pump delivery of the media, including chemical raw materials, reaction intermediates, such as the general is a corrosive medium. The materials of pump selection of an appropriate and reasonable, with corrosion resistance; and the chemical pump for transporting the media sometimes is medium high temperature, flow of liquid material, the reaction required and the resulting heat carrier liquid. For example: condensate pump, boiler feed pump, heat pump. Chemical pump delivery of low temperature medium, there are many kinds, such as liquid oxygen, liquid nitrogen, methane and other, the pump temperature work mostly in a 20 - 10 DEG C. No matter transport resistance to corrosion, high temperature or low temperature chemical pump, material selection and structure must be appropriate, must have sufficient strength, design and manufacture of pump parts to thermal shock, thermal expansion and low temperature deformation, the influence of cold brittleness. To ensure that the pump can be safe and stable operation.
2. To meet the needs of chemical process: Pump in chemical production, not only to transport liquid materials and requirements of the process to provide the necessary pressure, must also ensure the delivery amount of material, in certain chemical unit operation, pump flow and head to stabilize, maintain a high efficiency and reliable operation of the pump.
3. Resistance to abrasion and erosion: contains solid particles suspended in the chemical pump delivery of logistics, while the pump impeller chamber while others work under high pressure and high flow rate, pump parts surface protection layer is destroyed, its life is short, so must improve the chemical pump wear resistance, erosion resistance, which requires materials of pump selection of wear resistant steel, ceramics, cast iron, and so on, the choice of erosion resistant titanium, manganese.
4 . No leakage or less leakage: flammable, explosive, poisonous and harmful liquid chemical pump delivery of most of the media, once the leak will seriously pollute the environment, endanger the personal safety and worker's physical and mental health, but do not meet the factory and clean and civilized factory without leakage, which must ensure operation of chemical pump does not leak, in pump seal on the new technology, new material, according to the operating rules and high quality maintenance.
5. Reliable operation: the operation of the chemical centrifugal pump is reliable, including two meanings: first, the long period of operation is not a failure; the two is running in a variety of parameters. The reliability of operation is very important to the chemical production. If the pump often fails, it will not only result in regular production, affect production and economic benefits, and sometimes may cause accidents in chemical systems. Chemical pump speed fluctuations will cause fluctuations in flow and pump outlet pressure, so the chemical production can not normal or system reaction affected, the material can not balance, not only wasteful, and even cause decline in the quality of the products or the rejection of the products. So the chemical pump has the characteristic that must run smoothly and reliably.
2017年2月9日星期四
Selection of Start Mode of Centrifugal Pump Control
Centrifugal pump used in the cage motor configuration centrifugal pump control cabinet has a high starting current when starting.
Motor power is less than 4kW, the centrifugal pump control cabinet starting mode using a direct closing circuit and soft starter. Motor power is greater than 4kW, the centrifugal pump control cabinet priority to use the star delta connection method, starting transformer, soft starter and inverter with the starting operation mode.
Centrifugal pump control cabinet in the direct closing of the circuit, the motor winding end of the wrong connection into a triangular connection, so that the motor starts
The torque required to ensure mechanical rotation is instantaneously obtained. The complete unit will soon reach the normal operating speed.
For motors. This turn-on method is most advantageous even when the starting current is increased to eight times the rated current. Because of the large capacity of the motor, this method will close the grid load soared, resulting in interference around the device voltage disturbance phenomenon wins, so the use of public low-voltage power grid (400V). Should be strictly abided by the power supply industry on the power is greater than 5.5kW when the direct operation of the provisions.
Motor power is less than 4kW, the centrifugal pump control cabinet starting mode using a direct closing circuit and soft starter. Motor power is greater than 4kW, the centrifugal pump control cabinet priority to use the star delta connection method, starting transformer, soft starter and inverter with the starting operation mode.
Centrifugal pump control cabinet in the direct closing of the circuit, the motor winding end of the wrong connection into a triangular connection, so that the motor starts
The torque required to ensure mechanical rotation is instantaneously obtained. The complete unit will soon reach the normal operating speed.
For motors. This turn-on method is most advantageous even when the starting current is increased to eight times the rated current. Because of the large capacity of the motor, this method will close the grid load soared, resulting in interference around the device voltage disturbance phenomenon wins, so the use of public low-voltage power grid (400V). Should be strictly abided by the power supply industry on the power is greater than 5.5kW when the direct operation of the provisions.
How to Measure the Speed of Centrifugal Pump
How to measure the Centrifugal pump speed, how to measure the pump speed
The speed measurement can be used to determine the rotational speed of the object. A different method can be used to measure the pump speed.
So how to measure the Centrifugal pump speed?
1, magnetic induction speed sensor. The magnetic field lines through the sensor coil change, during sensing
The periodic voltage is generated in the coil. The voltage process is counted. Measured the speed of the pump.
2, manual vortex tachometer with the end of the shaft or motor shaft at the end of the tachometer.
3, the electronic counter (in the high precision when used). The pulse signal proportional to the pump speed can be transmitted from the pump shaft of the centrifugal pump to the counter without contact (flash method or magnetic method).
4, slip meter (slip coil or magnetic needle). Install at a distance from the motor at a certain distance.
The speed measurement can be used to determine the rotational speed of the object. A different method can be used to measure the pump speed.
So how to measure the Centrifugal pump speed?
1, magnetic induction speed sensor. The magnetic field lines through the sensor coil change, during sensing
The periodic voltage is generated in the coil. The voltage process is counted. Measured the speed of the pump.
2, manual vortex tachometer with the end of the shaft or motor shaft at the end of the tachometer.
3, the electronic counter (in the high precision when used). The pulse signal proportional to the pump speed can be transmitted from the pump shaft of the centrifugal pump to the counter without contact (flash method or magnetic method).
4, slip meter (slip coil or magnetic needle). Install at a distance from the motor at a certain distance.
Power calculation formula of centrifugal pump
The characteristic curve of centrifugal pump is the inherent characteristic of the pump, it has nothing to do with the use of the outside world. However, once the pump is arranged in a certain pipeline system, the actual work is not only related to the characteristics of the centrifugal pump itself, but also depends on the working characteristics of the pipeline. Therefore, to select and make good use of centrifugal pump, it is also considered the characteristics of the pipeline at the same time.
Because there are various losses in the operation of the centrifugal pump, the effective pressure head and flow rate of the pump are lower than the theoretical value, and the input pump power is higher than the theoretical value.
H______ pump effective pressure head, that is, the unit volume of liquid in the gravity field from the pump to get the energy, m;
Q ______ the actual flow ofpump, m3/s;
P ______ liquid density, kg/ m3;
Ne______ the effective power of the pump, that is, the mechanical energy of the liquid from the pump unit at the time of the unit, W.
Effective power can be written as Ne = QH = g
The power of the centrifugal pump is referred to as the pump shaft power, which is expressed by N. The effective power and shaft power is defined as the ratio of the total pump efficiency, namely =Ne/N according to the above analysis, we can understand the energy loss in the centrifugal pump to work, how to improve the power of centrifugal pump for efficient use of products of great significance. Each product has a shortage of places, these weaknesses may lead to a reduction in the use of the product performance. At this time the power is a very good test method, how to maximize the power of the product, the need for professionals to do more work and research.
Reasons for the poor rotation of multi-stage centrifugal pumps
1.Multistage centrifugal pump parts with under magnetized. Before the assembly of all parts shall be demagnetization.
2.Multi stage centrifugal pump and engine shaft coupling. The coaxial degree should be guaranteed within 0.1mm.
3.Needle sleeve unqualified or needle breakage. Repair or replace.
4.Multi-stage centrifugal pump working oil output is blocked. Removal of foreign body.
5.Pump axial clearance or radial clearance is too small. Readjust repair.
6.Multi-stage centrifugal pump with dirt. Disintegration to remove foreign body.
7.Assembly error. The processing base of multistage centrifugal pump two pin hole surface is not the assembly datum, such as the pin into the first, then tighten the screws, the pump will not turn. The correct method is, while rotating the multistage centrifugal pump side screw, finally drilled pin holes and into the pin.
Application of packing seal in multi-stage pump
Application of packing seal in multi-stage pump
1.There is a certain plastic, under the effect of the compression force can produce a certain radial force and contact with the close shaft.
2.There is enough chemical stability, non polluting media, the filler is not the medium foam expansion, filler in the impregnation agent is not dissolved, the filler itself is not corrosive sealing surface.
3.Filler self lubrication performance is good, wear resistance, friction coefficient is small.
4.There is a small amount of axis offset, the filler should have enough flexibility.
5. Simple manufacture, convenient filling
To this end, often need to fill the compression level to adjust, after packing the lubricant in the running for a period of time has been lost, and then squeezed out some lubricant, pressing force relaxation while compensating for volume changes caused by filling. Of course, such a regular squeeze filler, and finally will make the dipping agent depleted, so the regular replacement of filler is necessary. In addition, in order to maintain the liquid film and take away the friction heat, to allow a small amount of leakage is also necessary.
2017年2月7日星期二
The difference between multi - stage centrifugal pump and single - stage centrifugal pump
The difference between multi-stage pump and single-stage pump
As a wide range of centrifugal pump products in the selection of multi-stage centrifugal pump and single-stage centrifugal pump can sometimes meet the same parameters, the user does not know when to choose the product of choice which series of products, but do not know the multi- Centrifugal pump and single-stage centrifugal pump where the difference.
The difference between multi-stage pump and single-stage pump is mainly multi-stage centrifugal pump used in two or more than two impeller is called multi-stage centrifugal pump, and single-stage centrifugal pump is only one impeller so called single-stage centrifugal pump. Multi-stage centrifugal pump if the use of multiple impeller in the top of an impeller will be more than one level of lift, the main feature is the high-lift, and single-stage centrifugal pump in the lift can not reach the effect of multi-stage centrifugal pump, Building water supply or high-level fire with water are multi-stage centrifugal pump products, single-stage centrifugal pump is generally used for factory or low-pressure booster water use.
The difference between multi-stage pump and single-stage pump There are prices in the above single-stage centrifugal pump and multi-stage centrifugal pump price difference between the more obvious, included in the parameters of two types of pumps can meet the requirements of single-stage centrifugal pump than multi- Centrifugal pump price is much less, because in the manufacturing cost for single-stage centrifugal pump than multi-stage centrifugal pump manufacturing costs less. Therefore, single-stage centrifugal pump to meet the conditions of the conditions we recommend the selection of single-stage single-suction centrifugal pump is better.
Vertical multistage pump and vertical single-stage pump difference is: vertical multi-stage pump it is not suction, and vertical single-stage centrifugal pump installed after the end of the valve has a certain suction.
As a wide range of centrifugal pump products in the selection of multi-stage centrifugal pump and single-stage centrifugal pump can sometimes meet the same parameters, the user does not know when to choose the product of choice which series of products, but do not know the multi- Centrifugal pump and single-stage centrifugal pump where the difference.
The difference between multi-stage pump and single-stage pump is mainly multi-stage centrifugal pump used in two or more than two impeller is called multi-stage centrifugal pump, and single-stage centrifugal pump is only one impeller so called single-stage centrifugal pump. Multi-stage centrifugal pump if the use of multiple impeller in the top of an impeller will be more than one level of lift, the main feature is the high-lift, and single-stage centrifugal pump in the lift can not reach the effect of multi-stage centrifugal pump, Building water supply or high-level fire with water are multi-stage centrifugal pump products, single-stage centrifugal pump is generally used for factory or low-pressure booster water use.
The difference between multi-stage pump and single-stage pump There are prices in the above single-stage centrifugal pump and multi-stage centrifugal pump price difference between the more obvious, included in the parameters of two types of pumps can meet the requirements of single-stage centrifugal pump than multi- Centrifugal pump price is much less, because in the manufacturing cost for single-stage centrifugal pump than multi-stage centrifugal pump manufacturing costs less. Therefore, single-stage centrifugal pump to meet the conditions of the conditions we recommend the selection of single-stage single-suction centrifugal pump is better.
Vertical multistage pump and vertical single-stage pump difference is: vertical multi-stage pump it is not suction, and vertical single-stage centrifugal pump installed after the end of the valve has a certain suction.
Single-stage double-suction centrifugal pump features and appearance structure
Single-stage double-suction centrifugal pump, single-stage double-suction centrifugal pump characteristics, single-stage double suction centrifugal pump structure
First, the characteristics of single-stage double-suction centrifugal pump
Single-stage double-suction centrifugal pump is characterized by large flow, high head; pump is open in the level, maintenance without dismantling the motor and pipeline, as long as the pump cover can be opened for inspection and maintenance; Layout, the basic impeller axial balance, so the operation is more stable; as the pump is relatively bulky, covers an area of large, it is suitable for use. Single-stage double-suction centrifugal pump currently has S, Sh two series. The S series pump is a newer product of Sh series pump. Its performance index is more advanced than Sh series pump. Its scope of application is: pump inlet diameter is 150 ~ 1 400 mm, rotational speed is 360 ~ 2 900 r / min, 18 000 m3 / h, the head is 12-125 m. Widely used in hilly and mountainous areas of large-scale irrigation.
Second, single-stage double-suction centrifugal pump structure
Single-stage double-suction centrifugal pump shape shown in Figure 1-8, the single-stage double suction centrifugal pump structure shown in Figure 1-9. Its main parts and single-stage single-suction centrifugal pump is basically similar, the difference is: single-stage double-suction centrifugal pump impeller is symmetrical, as if by two identical single-suction impeller back to back together, water from Both sides into the impeller. The impeller is fixed with the key, shaft sleeve and two side sleeve nuts. The axial position of the impeller can be adjusted by the sleeve nut. The pump cover and pump body of the single stage double suction centrifugal pump together form the semi-helical suction chamber and the snail pressure Out of the room. Pump suction and outlet are cast in the pump body, was horizontal, perpendicular to the pump shaft. After the flow of water from the suction mouth, along the semi-spiral inhalation chamber from both sides into the impeller, so the pump known as single-stage double-suction centrifugal pump; pump cover and the pump body is open in the horizontal, Said single-stage double-spiral volute centrifugal pump. Single-stage double-suction centrifugal pump impeller inlet and the outer edge of the Department fitted with two leaking ring, said double suction damping ring. Double-suction pump in the pump shaft piercing the pump at both ends of the total installed with two sets of packing seal, the pump is running when the pump ring, , A small amount of high-pressure water through the pump cover in the open surface of the groove and seal ring flow into the packing room, the role of water sealing; double suction pump from the inlet direction, the right end of the shaft coupling, according to need The coupling is mounted on the left end of the shaft, and both ends of the pump shaft are supported by bearings. Bearing type generally single row radial ball bearings, when the shaft diameter and speed of the product Dn,> 300 000 rruu. R / min when the sliding bearing.
First, the characteristics of single-stage double-suction centrifugal pump
Single-stage double-suction centrifugal pump is characterized by large flow, high head; pump is open in the level, maintenance without dismantling the motor and pipeline, as long as the pump cover can be opened for inspection and maintenance; Layout, the basic impeller axial balance, so the operation is more stable; as the pump is relatively bulky, covers an area of large, it is suitable for use. Single-stage double-suction centrifugal pump currently has S, Sh two series. The S series pump is a newer product of Sh series pump. Its performance index is more advanced than Sh series pump. Its scope of application is: pump inlet diameter is 150 ~ 1 400 mm, rotational speed is 360 ~ 2 900 r / min, 18 000 m3 / h, the head is 12-125 m. Widely used in hilly and mountainous areas of large-scale irrigation.
Second, single-stage double-suction centrifugal pump structure
Single-stage double-suction centrifugal pump shape shown in Figure 1-8, the single-stage double suction centrifugal pump structure shown in Figure 1-9. Its main parts and single-stage single-suction centrifugal pump is basically similar, the difference is: single-stage double-suction centrifugal pump impeller is symmetrical, as if by two identical single-suction impeller back to back together, water from Both sides into the impeller. The impeller is fixed with the key, shaft sleeve and two side sleeve nuts. The axial position of the impeller can be adjusted by the sleeve nut. The pump cover and pump body of the single stage double suction centrifugal pump together form the semi-helical suction chamber and the snail pressure Out of the room. Pump suction and outlet are cast in the pump body, was horizontal, perpendicular to the pump shaft. After the flow of water from the suction mouth, along the semi-spiral inhalation chamber from both sides into the impeller, so the pump known as single-stage double-suction centrifugal pump; pump cover and the pump body is open in the horizontal, Said single-stage double-spiral volute centrifugal pump. Single-stage double-suction centrifugal pump impeller inlet and the outer edge of the Department fitted with two leaking ring, said double suction damping ring. Double-suction pump in the pump shaft piercing the pump at both ends of the total installed with two sets of packing seal, the pump is running when the pump ring, , A small amount of high-pressure water through the pump cover in the open surface of the groove and seal ring flow into the packing room, the role of water sealing; double suction pump from the inlet direction, the right end of the shaft coupling, according to need The coupling is mounted on the left end of the shaft, and both ends of the pump shaft are supported by bearings. Bearing type generally single row radial ball bearings, when the shaft diameter and speed of the product Dn,> 300 000 rruu. R / min when the sliding bearing.
Characteristics and Model Meaning of Pipeline Centrifugal Pump
The characteristics of pipeline centrifugal pump, pipe centrifugal pump model significance
Pipeline centrifugal pump is mainly used for pipeline water pressure to increase the occasion. Pipeline centrifugal pump It is directly connected with the pipeline, the motor is located above the pump, pump suction and outlet diameter the same, and in the same horizontal plane, the bottom of a square base, can be directly installed on the concrete foundation. Small pipe pump to be installed directly in the pipeline, the pump should be supported on both sides of the pipeline.
Pipeline centrifugal pump is mainly characterized by high efficiency and energy saving, low vibration, low noise, simple structure, easy installation, small footprint, it can be used for conveying water, petroleum, chemical liquid. Equipped with outdoor explosion-proof motor of the pipeline pump is suitable for outdoor operation.
Pipe centrifugal pump model meaning: for example, ISG50-125A 50 - pump suction and outlet diameter of 50mm; commonly used pipeline centrifugal pump to the letter ISG said, IRG-hot water pipeline centrifugal pump, ISGB-proof pipeline centrifugal pump, IHG- Stainless steel chemical pipeline centrifugal pump, 125-behalf of the pump impeller diameter m; A-wheel diameter after a small car.
In addition to these types of pipeline centrifugal pump, the pipeline centrifugal pump, such as not qualified for some special occasions, we can also make other types of pipeline centrifugal pump products such as demolition of the pipeline centrifugal pump or large flow pipe centrifugal pump products for selection .
Pipeline centrifugal pump is mainly used for pipeline water pressure to increase the occasion. Pipeline centrifugal pump It is directly connected with the pipeline, the motor is located above the pump, pump suction and outlet diameter the same, and in the same horizontal plane, the bottom of a square base, can be directly installed on the concrete foundation. Small pipe pump to be installed directly in the pipeline, the pump should be supported on both sides of the pipeline.
Pipeline centrifugal pump is mainly characterized by high efficiency and energy saving, low vibration, low noise, simple structure, easy installation, small footprint, it can be used for conveying water, petroleum, chemical liquid. Equipped with outdoor explosion-proof motor of the pipeline pump is suitable for outdoor operation.
Pipe centrifugal pump model meaning: for example, ISG50-125A 50 - pump suction and outlet diameter of 50mm; commonly used pipeline centrifugal pump to the letter ISG said, IRG-hot water pipeline centrifugal pump, ISGB-proof pipeline centrifugal pump, IHG- Stainless steel chemical pipeline centrifugal pump, 125-behalf of the pump impeller diameter m; A-wheel diameter after a small car.
In addition to these types of pipeline centrifugal pump, the pipeline centrifugal pump, such as not qualified for some special occasions, we can also make other types of pipeline centrifugal pump products such as demolition of the pipeline centrifugal pump or large flow pipe centrifugal pump products for selection .
Disassembly and assembly of centrifugal pump
Centrifugal pump disassembly and assembly assembly, is to check, repair the pump when the important work. Some special type or large centrifugal pump in the factory and transport process, and sometimes need to be dismantled into parts, such as single-stage double-suction centrifugal pump open in the pump unit installed, in accordance with national standards and corporate standards It is required that the pump be assembled correctly. The overall pump factory in the manufacturer's rust-proof guarantee period, the internal parts should not be demolished, only clean appearance. When more than rust-proof period or obvious defects to be removed, the demolition, cleaning and inspection should be consistent with the provisions of the equipment technical documents. When no technical requirements, the national standard may refer to the general provisions. Disassemble the water pump, in the assembly before the pump parts seat rigorous inspection, the pump's main parts, components and ancillary equipment, in the surface and set the parts, parts of the end shall not forgive scratches and scratches; Cracks, crush and other defects. After cleansing the parts, remove the water and parts, parts and equipment should be coated with lubricating oil and the order according to the classification of heavy volume.
Disassembly or Assembly Before assembling a centrifugal pump, various tools need to be prepared in advance, including the fitter tools (such as wrenches, hand hammers, screwdrivers) and inspection tools (such as the micrometer card, feeler) and some auxiliary, Supplies (such as bolts loose agent, lubricants, gaskets) and so on.
Disassembly or Assembly Before assembling a centrifugal pump, various tools need to be prepared in advance, including the fitter tools (such as wrenches, hand hammers, screwdrivers) and inspection tools (such as the micrometer card, feeler) and some auxiliary, Supplies (such as bolts loose agent, lubricants, gaskets) and so on.
The Advantages of Centrifugal Pump and the Composition of Centrifugal Pump
The advantages of centrifugal pump, centrifugal pump device composition
First, the advantages of centrifugal pump
Centrifugal pumps have many advantages over other types of pump centrifugal pumps, such as uniform flow, smooth operation, low vibration, high speed, low installation and maintenance cost, wide application range (including flow, head and adaptability to medium). Therefore, the centrifugal pump is widely used in chemical production of a chemical pump.
Second, the composition of centrifugal pump
Centrifugal pump device is a centrifugal pump and a certain pipeline, and the valve and the composition of the delivery system
The liquid to be delivered by the centrifugal pump to supply energy, through the pipeline transportation system to a certain place. Pipeline transportation system refers to the suction pipe, discharge pipe and pipe fittings and so on.
First, the advantages of centrifugal pump
Centrifugal pumps have many advantages over other types of pump centrifugal pumps, such as uniform flow, smooth operation, low vibration, high speed, low installation and maintenance cost, wide application range (including flow, head and adaptability to medium). Therefore, the centrifugal pump is widely used in chemical production of a chemical pump.
Second, the composition of centrifugal pump
Centrifugal pump device is a centrifugal pump and a certain pipeline, and the valve and the composition of the delivery system
The liquid to be delivered by the centrifugal pump to supply energy, through the pipeline transportation system to a certain place. Pipeline transportation system refers to the suction pipe, discharge pipe and pipe fittings and so on.
Classification and structure characteristics of multistage pump
Multistage pump is a pump with two or more than two impeller. Usually the structure has the spiral case type multistage pump and the sectional type multistage pump.
The spiral case type multistage pump is generally used in the open type structure to facilitate the maintenance, and is advantageous for the symmetrical arrangement of the impeller, and reduces the axial force on the rotor. But the structure of technology and less: Series increasing, the shape of the pump body and cover more complex, pump dimensions is large, especially level and need to configure some level between channel, the pump complex shape. And when the series more, head higher, the opening of the sealing surface is more difficult. Based on these factors, the wide application of this structure is limited.
Segmented multi-stage pump compact structure, is conducive to improve the degree of standardization, generalization. Because of the structure of the pump head depends on the pump series, so the head of the pump range is wider.
Power calculation formula of centrifugal pump
The characteristic curve of centrifugal pump is the inherent characteristic of the pump, it has nothing to do with the use of the outside world. However, once the pump is arranged in a certain pipeline system, the actual work is not only related to the characteristics of the centrifugal pump itself, but also depends on the working characteristics of the pipeline. Therefore, to select and make good use of centrifugal pump, it is also considered the characteristics of the pipeline at the same time.
Because there are various losses in the operation of the centrifugal pump, the effective pressure head and flow rate of the pump are lower than the theoretical value, and the input pump power is higher than the theoretical value.
H______ pump effective pressure head, that is, the unit volume of liquid in the gravity field from the pump to get the energy, m;
Q ______ the actual flow ofpump, m3/s;
P ______ liquid density, kg/ m3;
Ne______ the effective power of the pump, that is, the mechanical energy of the liquid from the pump unit at the time of the unit, W.
Effective power can be written as Ne = QH = g
The power of the centrifugal pump is referred to as the pump shaft power, which is expressed by N. The effective power and shaft power is defined as the ratio of the total pump efficiency, namely =Ne/N according to the above analysis, we can understand the energy loss in the centrifugal pump to work, how to improve the power of centrifugal pump for efficient use of products of great significance. Each product has a shortage of places, these weaknesses may lead to a reduction in the use of the product performance. At this time the power is a very good test method, how to maximize the power of the product, the need for professionals to do more work and research.
Cause and harm of centrifugal pump cavitation
The reason of low temperature centrifugal pump cavitation: pump through the rotation of the impeller on the liquid work, so that the liquid energy increases. In the interaction process, the velocity and pressure of the liquid changes. In general, the inlet of the impeller of the centrifugal pump is the place where the pressure is lowest. If the local pressure is equal to or lower than the temperature in the vapor pressure of liquid, gas and steam will be dissolved in the liquid from the liquid in a large number of escape, forming many mixed steam and gas bubbles. These small bubbles with the liquid flow to high pressure areas, due to air bubbles within and around the bubble is greater than the vaporization pressure, vaporization pressure, pressure difference. Under the pressure difference, the bubble burst and re condensed. In the condensation process, the liquid particles from all around to the bubble center to accelerate movement, in the condensation of the moment, the particles collide with each other, resulting in a high local pressure. These bubbles, if they break down near the metal surface, are condensed, and the liquid mass is like a myriad of small bullets, hitting on the surface of the metal. Under high pressure and high frequency, the surface of the metal is gradually destroyed by fatigue, which is often referred to as erosion. In the bubble generated by the inclusion of a number of active gases (such as oxygen, etc.), with the heat released by the bubble condensation, the metal from the chemical corrosion. Chemical corrosion and mechanical erosion of the common role, it is more accelerated the speed of metal damage, this phenomenon is the phenomenon of cavitation damage.
At the beginning of the centrifugal pump cavitation, the cavitation area is small, the normal work of the pump has no obvious effect, and there is no obvious reflection of the pump performance curve. But when cavitation develops to a certain extent, the bubbles produced, affecting the normal flow of liquid, and even cause the liquid flow interruption, vibration and noise; at the same time, pump flow, head and efficiency decrease, is also apparent in the pump performance curve. Serious when the pump can not work. In order to avoid cavitation phenomenon, in the process of design, should make the liquid in the pump before the degree of cooling, at the same time the pump should be installed in the lower position, so that the liquid inlet has a certain static pressure head. In addition to pay attention to the cold, as far as possible to reduce the loss of cold.
2017年2月6日星期一
Installation instructions of horizontal centrifugal pump
1.In the installation, you need to check parts, such as motor, water pumps, etc., especially the pipeline, whether there are impurities affect the operation, to avoid damage to the parts when working.
2.In order to maximize the performance of the equipment to play, and as far as possible to extend the use of equipment, installation of pipeline equipment should have different support.
3.Due to the temperature limit, in the transmission of high temperature liquid, in order to ensure the pipeline with the force, in the early installation, the bottom bolt is not fixed, and then the pipeline with the temperature change and synchronous movement.
4.Import and export flange specifications need to be consistent with the pipeline configuration specifications.
5.The installation should be installed at the entrance of a filter to avoid the debris into the pump and affect the efficiency of the work or damage to the equipment. In addition, the outlet of the check valve should be installed outside.
6.Due to the scope of application of the centrifugal pump may be in the suction range, so the import and export pipeline to minimize the twists and turns, to ensure that there will be no leakage of water vapor phenomenon.
7.For the whole work and maintenance process can be carried out smoothly, at the time of installation, the inlet and outlet pipe to install a separate regulation and pressure testing equipment to ensure the timely detection and treatment of abnormal situation.
8.A full set of installation is completed, start the test, check whether there is friction and the card dead phenomenon, OK no problem can be put into use.
The reason and solution of the shortage of the centrifugal pump flow
1.Import and export pipeline, flow of centrifugal pump impeller partially blocked, the scale deposition in the pump inside. Check the pipe and pump cavity to remove the blockage, re adjust the valve size.
2.The voltage is low. The solution to the problem of centrifugal pump flow: stable voltage.
3.Centrifugal pump impeller wear. Solution: replace the new impeller.
4.Is not the above several reasons please according to the following centrifugal pump does not water the reason comprehensive inspection.
5.The centrifugal pump inlet or outlet valve is not open, the inlet pipe is blocked, the pump cavity impeller flow channel is blocked. Check whether the import and export of the valve is closed to open the closed valve, check the inlet and outlet pipes and pump impeller is a debris blockage removal.
6.The motor's running direction is not right, the motor phase speed is very slow. Change the motor wiring to adjust the motor's turn, check the power supply into the wire fastening good motor wiring.
7.The centrifugal pump inlet pipe leakage, leading to the centrifugal pump has been in the state of air suction. Check the leakage point of the imported pipeline leak to repair the leak, tighten the cover, remove the air.
8.The centrifugal pump is not filled with liquid, the pump cavity has air. Unscrew the pump cover or open the exhaust valve and discharged into the air.
9.The centrifugal pump inlet pipeline centrifugal pump water flow lack the required flow, or suction is too high, the inlet pipe valve centrifugal pump seal is not good Water Leakage. Check the pump (pipe network and the use of water pipe with the suction process is prone to this phenomenon), adjust the distance to shorten the distance, or replace the self suction pump. 10, pump outlet pipe resistance is too large, pump selection is not appropriate or the pump head can not reach. Reduce the pipe bend, bend too much can be installed on the automatic exhaust valve, exclude the pipeline corner of the condensation of air, or re election pump
2017年2月5日星期日
How to solve the problem of horizontal multi-stage pump
1.Horizontal multi-stage pump does not absorb water or water. The cause of this failure is mostly due to the end of valve stuck, part of the blockage of water, high water or water pipe leakage is too high. Should be checked one by one, taken at the end of valve repair, clear the blockage and correct the steering and other processing.
2.Pipeline leakage or leakage. No more than nuts tightened due. If the leakage is not serious, can be applied to cement slurry, mud or soft soap in the leakage; if the joints Water Leakage, tighten the nut wrench can be used. Serious leakage, leakage, must be re assembled.
3.Multi-stage centrifugal pump severe vibration. May be the motor rotor is not balanced or shaft coupling. Sometimes bearing wear, bending, rotating parts of the relaxation, rupture, pipeline stent is not strong also cause vibration. Should be adjusted, reinforcement, inspection or replacement.
4.The impeller is bad. When the damage is not large, can be repaired. Hard alloy should be replaced or plated when the damage is serious. Completely damaged, the impeller should be removed, the repair shop to repair.
5.Horizontal multi-stage pump shaft bending. Is due to the impact load, belt pulled too tight, causing incorrect installation. If the bend is not serious, can be used manually screw to correct, but not too hard, in case of a complete break.
Structure of clean water horizontal centrifugal pump
1.Horizontal centrifugal pump housing (that is, pump body and pump cover) to form a pump studio. Impeller, shaft and rolling bearings, etc. for the pump rotor. The suspension bearing part supports the rotor of the pump, and the radial force and axial force of the rolling bearing are affected by the pump.
2.In order to balance the axial force of pump impeller, pump the most before and after is provided with a sealing ring, and a balance hole in the impeller hub, the axial force of pump impeller back some small, no sealing ring and balance hole.
3.Axial horizontal centrifugal pump sealing ring is composed of packing gland, packing ring and packing etc., to prevent air or a large number of Water Leakage. The impeller of the pump if the balance cavity and impeller with soft packing suction port as the impeller inlet liquid in the vacuum state, it is very easy to intake along the surface of the shaft sleeve, the packing ring through the pump cover hole is arranged in the packing chamber, the pump room pressure water to fill material for sealing ring. If there is no balance hole of the impeller of the pump, the liquid pressure on the back side of the impeller is greater than the atmospheric pressure, so there is no leakage problem, therefore, the packing ring can not be filled.
4.In order to avoid shaft wear, in the shaft through the packing chamber is equipped with protective sleeve. A quasi O type sealing ring between the shaft sleeve and the shaft, along with the surface to prevent intake or Water Leakage.
5.Pump transmission is through the extension of the elastic coupling and motor coupling, the rotation direction of the pump, from the driver to see, for the clockwise rotation.
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