What are the common problems with centrifugal pumps?

1. The pump is slow to load water.

Reason: The gap between the front liner and the impeller is large, the outlet pipe cannot seal the air, and the discharge is full.

Solution: Adjust the gap, adjust the outlet pipe, and install the vacuum device.

2. The outlet pressure is small and the flow rate is small.

Causes: Air in the pump, large gap between the impeller and the front liner, poor clutch closure, worn impeller or liner.

Solution: Drain the gas in the pump, adjust the clearance, adjust the clutch friction plate clearance, replace the impeller or liner.

3. The pump wears out quickly.

Causes: poor construction environment (large particles), long conveying distance, long inlet pipeline.

Solution: Replace the sand field, add afterburner units, shorten the length of the inlet pipe and reduce cavitation.

4. Pump vibration or abnormal sound.

Causes: The pump shaft is not concentrified with the diesel engine (or motor), the impeller is unbalanced, and the bearing is damaged.

Solution: adjust the concentricity, balance test the impeller, and replace the bearing.

(1)The prime mover or power supply is not normal. The solution is to check the power supply and prime mover condition.

2) The pump is stuck. The treatment method is to check with a hand-coiled coupling, and if necessary, disassemble and check to eliminate the dynamic and static part of the fault.

3) The filler is pressed too tightly. The treatment is to relax the filler.

4) The discharge valve is not closed. The solution is to close the discharge valve and restart it.

5) The balance tube is not smooth. The solution is to unclog the balance tube.

Key Benefits: Because it is impossible to form an absolute vacuum at the impeller inlet, the suction height of the centrifugal pump cannot exceed 10 meters, plus the loss along the way caused by the water flow through the suction pipeline, the actual allowable installation height (the height of the pump axis from the suction water surface) is far less than 10 meters. If the installation is too high, it will not absorb water; In addition, since the atmospheric pressure in the mountains is lower than in the plains, the installation height of the same pump in the mountains, especially in the high mountains, should be reduced, otherwise it will not be able to absorb water.

Content from user: dahuzi

This article analyzes in detail the common fault types of centrifugal pumps, such as centrifugal pump bearing heating, centrifugal pump can not deliver liquid, centrifugal pump flow, insufficient head, centrifugal pump seal leakage, centrifugal pump vibration or noise, centrifugal pump motor overload and other phenomena, and introduces in detail the reasons for the above fault phenomena and how to correctly deal with the above faults.

The common fault types and treatment methods of specific centrifugal pumps are shown in Table 1-1 below.

Table 1-1 Common fault types and treatment methods of centrifugal pumps.

Serial number Fault phenomenon cause treatment method

1 Shaft bearing heat 1, too much lubricating oil 2, too little lubricating oil 3, lubricating oil deterioration 4, unit misalignment 5, vibration 1, oil reduction 2, refueling 3, draining and cleaning the oil pool and adding new oil 4, check and adjust the alignment of the pump and prime mover 5, check the balance of the rotor or operate at a small flow rate

2 The pump cannot deliver the liquid 1, the suction pipeline or the pump is left with air 2, the inlet or outlet side pipeline valve is closed 3, the use of the head is higher than the maximum head of the pump 4, the pump suction pipe leakage 5, the wrong impeller rotation direction 6, the suction height is too high 7, the suction pipeline is too small or the debris is blocked 8, the speed does not match 1, fill the liquid, remove the air 2, open the valve 3, replace the pump with high head 4, eliminate the leakage on the inlet side 5, correct the motor steering 6, reduce the pump installation height, increase the pressure at the inlet 7, increase the suction pipe diameter8. Make the motor speed meet the requirements

3 Insufficient flow and head 1, impeller damage 2, excessive wear of the sealing ring 3, insufficient speed 4, inlet or outlet valve not fully opened 5, air leakage in the suction pipeline 6, blockage in the pipeline 7, medium density and pump.

<> centrifugal pumps are mainly used in boiler water, fire fighting water and construction water.

Centrifugal pumps can be widely used in electric power, metallurgy, coal, building materials and other industries to convey slurry containing solid particles. Such as hydraulic ash removal in thermal power plants, slurry transportation in metallurgical concentrators, coal slurry and heavy medium transportation in coal washing plants, etc. When the centrifugal pump works, the pump needs to be placed on land, the suction pipe needs to be placed in the water, and the pump needs to be started.

Due to the limitation of the structure, the mud pump and the submerged centrifugal pump need to be placed on the water surface when working, and the pump is put into the water, so it must be fixed, otherwise, the motor falling into the water will cause the motor to be scrapped. Moreover, because the length of the long shaft is generally fixed, the installation and use of the pump is more troublesome, and the application occasions are subject to many restrictions.

When using a pipeline centrifugal pump, the outlet flow of the pump often does not reach the parameters marked on the nameplate of the pipeline centrifugal pump, and the flow rate is unstable, this phenomenon is the cavitation of the centrifugal pump, so what to do if the cavitation phenomenon occurs in the centrifugal pump, the following is to share a few ways to deal with the cavitation of the centrifugal pump: (1) Select the shape and inlet position of the front cover plate of the vane pipeline centrifugal pump, and we have tested the cavitation performance of the impeller at the inlet edge position at various angles. Generally, the closer the blades are to the suction port of the pipeline centrifugal pump, the better the centrifugal anti-cavitation performance of the pipeline. That is, the larger the radius of the elbow at the inlet of the pipeline centrifugal pump, the better the anti-cavitation performance.

2) Double-suction centrifugal pump can also be used. The impeller of the double-suction pipeline centrifugal pump is equal to the effect of the impellers of two single-stage pipeline centrifugal pumps working together, so the double-suction centrifugal pump has better anti-cavitation performance. (3) The inlet diameter of the pipeline centrifugal pump can also be appropriately increased, for example, the caliber of the centrifugal pump pump is originally 50, and the pipe diameter of 65 can be selected for the inlet.

4) There is also a way to use a vertical multistage pump with an induction wheel, and the induction wheel of the multistage pipeline centrifugal pump is installed in front of the * impeller, which is called the pre-induction wheelWhen the liquid flows into the pump chamber, the inducer wheel will increase the energy of the liquid, which is equivalent to the pressurization of the liquid entering the rear impeller, so as to improve the self-priming of the pipeline centrifugal pump. (5) Due to the limitation of use conditions, it is impossible to completely avoid cavitation, so let the pump manufacturer choose the impeller material of the pump with anti-cavitation materials.

Impellers should be manufactured from materials that are resistant to cavitation. Generally commonly used materials are bronze, stainless steel, alloy steel and high nickel alloys. Practice has proved that the smoother the surface of the impeller channel, the better the strength and toughness of the material, the higher the hardness and chemical stability of the impeller, and the better the anti-cavitation performance of the pipeline centrifugal pump.

A centrifugal pump is a mechanical device that uses centrifugal force to increase the pressure of a liquid and deliver the liquid to a specified location. Its working principle is to drive the rotor to rotate through a motor, there is an impeller inside the rotor, the liquid is sucked into the center of the impeller and thrown around the impeller, thus creating a pressure difference, drawing the liquid from the suction inlet and pushing it to the outlet. Centrifugal pumps are commonly used to convey a variety of fluids such as clean water, sewage, petroleum, and chemicals.

Centrifugal pumps can be used in many different applications. In the construction industry, centrifugal pumps are commonly used to supply water, heat, air conditioning, and drainage to buildings. In the industrial sector, centrifugal pumps are used to convey chemical liquids, petroleum and liquid food.

In the agricultural sector, centrifugal pumps can be used for irrigation and livestock feeding. In addition, centrifugal pumps can be used in the field of fire protection and water treatment. In conclusion, centrifugal pumps are used in a wide range of applications and can be used in almost any situation where fluid needs to be transferred.

A centrifugal pump is a mechanical device that uses centrifugal force to transport liquids. It creates centrifugal force by rotating the impeller to create pressure in the pump body, which delivers the liquid to where it is needed. Centrifugal pumps are widely used in industry, agriculture, construction, municipal and other fields, such as transporting water, oil, chemical liquids, sewage treatment, air conditioning circulation, etc.

Centrifugal pumps are widely used in various industrial, civil and agricultural fields, and are mainly used in the following occasions:

1.Industrial field: conveying all kinds of liquids, chemical media, oil, natural gas, etc.

2.Civil field: water supply, drainage, air conditioning circulation, etc.

3.Agriculture: irrigation, drainage, fish pond farming, etc.

4.Construction field: water supply, drainage, fire protection, etc.

5.Energy: Conveying hot water, steam, fuel, etc.

6.Medical field: delivery of medicines, blood, etc.

In conclusion, centrifugal pump is a very important fluid transfer equipment that is widely used in various fields.

Centrifugal pumps are a common type of pump equipment, and common problems include:

Inability to drain liquid: This can be caused by insufficient filling pump (or incomplete gas discharge), wrong pump steering, too low pump speed, clogged filter, ineffective foot valve, etc.

Stop running after draining: It may be caused by the intake side gas is not discharged when filling the pump, the suction side is suddenly blocked by foreign matter, a large amount of gas is inhaled, the static head of the system increases, the resistance loss increases, the casing and impeller wear ring wear is too large, and other parts leakage.

Insufficient flow: It may be caused by cause inspection, partial blockage of pipes and impellers, scale accumulation, insufficient valve opening, low voltage, impeller wear, bearing wear, overload operation, friction, motor bearing damage, insufficient voltage, etc.

Noise and vibration: It may be caused by unstable pipeline support, liquid mixed with gas, cavitation, bearing damage, motor overload and heated operation, etc.

Motor heating: It may be caused by excessive flow, overload operation, friction, motor bearing damage, insufficient voltage, etc.

Water leakage: It may be caused by worn mechanical seals, sand holes or cracks in the horizontal centrifugal pump body, uneven sealing surfaces, loose installation bolts, etc.

Centrifugal pump FAQs include:

1.Unstable or reduced flow of the pump: This could be due to clogged inlet pipes, worn pump impellers, or too large a gap between the impeller and the pump casing.

2.Unstable or reduced pressure in the pump: This can be due to clogged inlet or outlet piping, worn pump impellers, or fouling inside the casing.

3.Excessive pump noise: This can be due to damage to the pump bearing, an imbalance in the pump impeller, or fouling inside the pump casing.

4.Pump temperature is too high: This may be due to poor lubrication of the pump bearings, too large clearance between the pump impeller and the pump casing, or fouling inside the pump casing.

5.Severe water leakage from the pump: It could be due to damage to the pump shaft seal, fouling inside the pump casing, or excessive clearance between the pump impeller and the pump casing.

Cavitation: Cavitation refers to the generation of a local pressure lower than the vapor pressure of the liquid in the suction section of the pump, resulting in the vaporization of the liquid and the formation of bubbles. When air bubbles flow with the liquid to a high-pressure area, the bubbles burst, which can lead to reduced pump performance, increased noise, vibration, and even damage to the pump's structure.

Air binding: Air binding is the accumulation of gas inside the pump in a certain part, which affects the normal operation of the pump. Air binding usually occurs during the suction section of the pump, causing the pump to lose its ability to self-prime and fail to deliver liquids properly.

Shaft seal leakage: Centrifugal pump shaft seals can leak liquid due to wear, aging, or improper installation. Shaft seal leaks can lead to degraded pump performance and can also pose a safety hazard to the environment and operators.

Overheating or wear of bearings: Centrifugal pump bearings can overheat or wear out due to lack of lubrication, overload, or improper installation, among other reasons. Bearing problems can lead to unstable pump operation, increased noise and vibration, and even failure.

Motor overheating: Motor overheating can be caused by overload, short circuit in windings, bearing failure, or poor heat dissipation, among other reasons. Overheating of the motor may cause the pump to not function properly or even burn out the motor.

Pump performance degradation: Centrifugal pump performance can be degraded due to impeller wear, cavitation, inlet clogging, bearing failure, etc. When the pump performance is reduced, it may lead to a decrease in flow and head, which cannot meet the needs of the system.

Noise and vibration: Centrifugal pumps may have noise and vibration problems during operation, which can be caused by impeller imbalance, bearing wear, improper pipe installation, cavitation, etc. Noise and vibration can affect the proper operation of the pump, reduce the service life and may also have an impact on the health of the operator.

Cavitation. Cavitation refers to when the pressure of the leaf surface of the tank is constant, such as the pressure in the center of the impeller is reduced to equal to the saturated vapor pressure at the current temperature of the conveyed liquid, a large number of bubbles will appear in the liquid at the inlet of the impeller, and these bubbles will be quickly crushed and condensed with the liquid entering the high-pressure area, resulting in the formation of a vacuum in the space where the bubble is located, and the surrounding liquid particles rush to the center of the bubble at a great speed, resulting in instantaneous impact pressure, so that the impeller part is quickly damaged, and at the same time, it is accompanied by the vibration of the pump body, making noise, and the flow rate of the pump. The head and efficiency are significantly reduced. This phenomenon is called cavitation.

When the centrifugal pump is started, if there is air in the pump, because the air density is very low, the centrifugal force generated after rotation is small, so the low pressure formed in the center area of the impeller is not enough to suck the liquid in the tank into the pump, and the centrifugal pump cannot transport the liquid even if it is started. This phenomenon is called air trapping and means that the centrifugal pump is not self-priming, so the casing must be filled with liquid before starting.

Summary. The common problems of centrifugal pumps are generally that the pump does not produce water, and is less than the factory flow.

The pump does not produce water treatment methods: the inlet and outlet of the pump are reversed or the motor wiring is reversed, and the inlet pipe is leaked, the pump is shut down for a long time without installing the check valve, the liquid in the pump cavity is insufficient or there is no liquid, the voltage is unstable and the coupling is damaged, and the suction stroke exceeds the self-priming capacity of the pump.

The treatment method of less than the factory flow is: replace the large-diameter inlet pipe, clean the impeller, open the large outlet valve, and restore the rated number of revolutions.

Common problems and solutions of centrifugal pumps.

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The common problems of centrifugal pumps are generally that the pump does not produce water, and is less than the factory flow. The pump does not produce water treatment methods: the inlet and outlet of the pump are reversed or the motor wiring is reversed, and the inlet pipe is leaked, the pump is shut down for a long time without installing the check valve, the liquid in the pump cavity is insufficient or there is no liquid, the voltage is unstable and the coupling is damaged, and the suction stroke exceeds the self-priming capacity of the pump.

The treatment method of less than the factory flow is: replace the large-diameter inlet pipe, clean the impeller, open the large outlet valve, and restore the rated number of revolutions.