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.
2017年2月16日星期四
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.
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