Daily maintenance method of acid and alkali resistant centrifugal pump

1. The inlet and outlet pressure, flow and motor current of the centrifugal pump shall be kept in the normal use standard, and it is prohibited to pump for a long time. The flow and head of the acid and alkali resistant centrifugal pump shall be controlled within the range indicated on the signboard as far as possible to ensure that the acid and alkali resistant centrifugal pump operates at the design point, so as to achieve the effect of energy saving and consumption reduction.
2. During the operation of acid and alkali resistant centrifugal pump, the bearing temperature shall not exceed the working temperature by 50 ℃, and the upper limit shall not exceed 90 ℃.
3. Check the sealing condition of centrifugal pump frequently, and report to the workshop for maintenance in case of leakage.
4. Always check the quality of lubricating oil and oil level indicator in the oil tank, and replace them immediately if they are found to be deteriorated to avoid false liquid level.
5. The filter press pump shall be sealed with cooling circulating water. The cooling circulating water shall be kept smooth. The cooling circulating water shall not be interrupted within one week after the new seal ring is replaced.
6. Check whether the pump base and motor are firm. If they are loose, the centrifugal pump will vibrate. Stop the pump immediately to check the root cause when the pump makes an abnormal noise.

7. The centrifugal pump shall be operated for 300 hours within 3 months to replace the lubricating oil, and the lubricating oil shall be replaced within 3-6 months for the second time. After 6~12 months, it shall be lubricated and replaced.
8. Check the condition of instruments and leads to see if the pipes are leaking or loose, or damaged in other forms. If maintenance is needed, it should be carried out immediately.
9. Whether the mechanical seal is always leaking. If there is a leak, the compression degree of the moving ring should be adjusted in time to ensure that the sealing surface does not leak. Do not press too tightly to reduce the service life of the sealing property. Note: The filter press pump is the most demanding working condition in the process flow, and also the position with the largest consumption of spare parts. When the sealing leakage is not serious, the seal will not be replaced. Generally, the closed circulation reuse system of the leaking liquid should be considered in the design, but it is subject to the scarcity of materials.
10. When the acid and alkali resistant centrifugal pump is used in cold winter, the liquid in the pump body and pipeline shall be completely discharged when it is stopped. Avoid freezing.
11. If the acid and alkali resistant centrifugal pump is not used for a long time, it is necessary to disassemble all the pumps, wipe off the water, coat the rotating parts and joints with grease, and install them properly for maintenance.
12. For pumps that are not used, turn the gear once before each shift to ensure that the pumps are in good use.
13. When the acid and alkali resistant centrifugal pump is to be stopped, first turn off the valve and pressure gauge, and then disconnect the motor power supply.

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Components of centrifugal pump

Centrifugal pumps are composed of many parts. They can be roughly divided into three categories according to the working state of each part during operation
Type: rotating part, fixed part J4: and connecting part. Take the single-stage single suction horizontal diaphragm pump as an example, as shown in Figure 2.4
The function, composition, structure and material of each part under.
2.2.1 Rotating parts
1 Impeller (also called working wheel)
The barking wheel is the main part of the water pump, or even the core part of the water pump. The centrifugal system depends on the high-speed rotation of the impeller
Transferring water for energy calibration.
The wheel rubber of the gear pump is composed of two circular covers. If there is a curved blade between the covers
The two cover plates are connected together, and the space groove enclosed by the two adjacent blades and the front and rear cover plates is generally referred to as the flow of water.

The shape and size of the impeller are determined by test and calculation, which can be generally divided into leather suction impeller and double suction impeller.
The front cover plate of the impeller with a round hole for water inlet is called a single suction impeller, and the front and rear cover plates of the impeller with a round 7L water inlet are called double suction impeller
Suction impeller.
It is a teaching suction impeller. It is equipped with a single-sided chock wheel cover plate for water intake, while the rear cover plate is H without the cover plate of the wheel intake; Symmetrical shape. It is a double suction impeller. The front and rear cover plates of the impeller are equipped with round water inlets
The cover plate is symmetrical and generally used for large flow centrifugal pumps.
In addition to sufficient mechanical strength, wear resistance and corrosion resistance of materials shall also be considered
Performance. Recently, most impellers of screw pumps are made of cast iron, cast steel and bronze, and hard plastic and alloy steel are also used.

using screw vacuum pump in common mistakes

How to prevent the motor of centrifugal pump from being burnt?

 Dadonghai Pump Wuxi Co., Ltd. is a professional centrifugal pump manufacturer. When selecting centrifugal pumps for customers, our pump manufacturers will provide perfect pre-sales services such as centrifugal pump models, centrifugal pump prices, etc. for customers’ reference, and our pump manufacturers can provide customers with customized pump products. This information is about how to prevent the motor of centrifugal pump from being burnt:

The motor may fail during operation, and burning is one of them, which not only affects the normal work, but also increases the cost, causing us a lot of trouble. There are many reasons why the motor is burnt out, which is related to the quality of the machine itself and whether the centrifugal pump is used correctly.
After the power is turned on, carefully observe the working condition of the centrifugal pump. The outlet water should be connected evenly and the centrifugal pump can be used without vibration and noise. In case of sudden shutdown during operation, disconnect the power supply immediately and check the cause. The interval between two starts of the centrifugal pump shall be limited to the return of all water in the centrifugal pump. If it starts too early, the motor will be burnt due to excessive resistance and water hammer in the water pipe. In addition, if the centrifugal pump is installed in the well, it should be noted that the flow of the centrifugal pump should be consistent with the normal water yield of the well, otherwise it will form an empty machine and burn the motor.
In order to ensure the normal operation of centrifugal pumps, Dadonghai Pump Industry reminds everyone to pay attention to the following points before using centrifugal pumps:
1. Check whether the centrifugal pump motor winding is open circuit. The insulation condition can be measured with a 500V megohmmeter. When the insulation resistance is lower than 0.5 megohm, the centrifugal pump cannot be used.
2. Remove the filter screen and check whether the rolling pump shaft is sensitive. If not, adjust it before use.
3. Whether the selection of gate fuse capacity is appropriate, and other wires cannot be used to replace the fuse.
4. Turn on the power and check whether the impeller works normally (the power on time shall not exceed 3–5 seconds, otherwise the motor may be burnt out.

How To Eliminate The Axial Force Of Roots Reciprocating Vacuum Unit

In depth analysis, can the magnetic pump run idle?

With the aggravation of the environmental protection situation, more and more chemical enterprises are required to use magnetic pumps to transport various corrosive materials. As we all know, magnetic pumps cannot idle. As long as they idle for a few minutes, the friction between the shaft and the shaft sleeve inside them will produce extremely high temperature, quickly wear the graphite bearings and shafts, and even burn the inner rotor.
In recent years, domestic magnetic pump manufacturers claim to be able to do anti idling magnetic pumps. Is it true? Does idling magnetic pump really work? Can it really idle for a long time?
Today, I would like to introduce some details to you. I hope it will be helpful to users.
At present, there are two kinds of idling magnetic pumps produced by some domestic manufacturers. One is that ceramic rolling bearings are used to replace the original sliding bearings. When the magnetic pump is short of liquid, the friction coefficient of the rolling bearings is low and the heat generated is relatively small. Therefore, the magnetic pump can be idling without burning the bearings and rotors. The disadvantages of this structure are: it cannot carry high torque, materials with higher density cannot be transported normally, and ceramic bearing balls are fragile.
The other is the LHC idling fluorine lined magnetic pump developed by Green Ring. This magnetic pump is a complete upgrade of the main shaft and shaft sleeve on the original traditional basis. It is filled with nano carbon powder technology to achieve the function of idling and self-lubricating. Relatively speaking, the latter is more in line with idling requirements in terms of technology and practical theory.

water ring compressor of manufacturer: basic characteristics of water ring compressor

The Harm of Centrifugal Pump Cavitation

 

The cavitation phenomenon of centrifugal pump is one of the common faults of centrifugal pump. Once cavitation occurs in the pump, its flow and head performance will not only decline, but also show obvious high noise and vibration. In serious cases, it will even interrupt the liquid flow in the pump and cannot work normally. Cavitation will also damage the flow passage components of the pump, and even affect the pipeline system. There are many reasons for cavitation, such as quality problems of centrifugal pump products, improper use of operators, etc. Before leaving the factory, the products will pass the quality inspection of multiple procedures, so the influence of human factors is greater. In the working state, the working environment and operating factors of centrifugal pumps account for the vast majority of the cavitation phenomenon of centrifugal pumps.
Cavitation will affect the normal operation of centrifugal pumps, causing many serious consequences.
The performance of centrifugal pump is reduced due to cavitation
Centrifugal pump transfers energy to the medium through the rotation of the impeller and converts it into the pressure energy of the medium. However, cavitation will seriously interfere with the energy transfer between the impeller and the liquid. When cavitation occurs, a large number of bubbles will be generated in the medium, which will block the impeller flow passage, and vortex will be generated locally, increasing the flow loss, reducing the pump flow, head and efficiency. In serious cases, it will also lead to flow interruption, making the centrifugal pump unable to work normally.
Cavitation will damage the overcurrent components
Among the flow passage components of centrifugal pump, the impeller is the part most affected by cavitation. When cavitation occurs, many small pits will gradually appear on the surface of metal materials, and then the pits will continue to develop and expand into honeycomb and groove shapes. In serious cases, perforation will occur, and even the impeller will break, seriously affecting the service life of the pump.
Noise and vibration of pump caused by cavitation
When cavitation occurs, high-frequency liquid collisions will produce various noises. In serious cases, the pump will emit crackling explosions, and at the same time, it will induce the vibration of the pump unit, which in turn will accelerate the generation and rupture of bubbles. When the frequency of liquid hammer is the same as the natural frequency of the pump unit, strong cavitation resonance will occur, which will rapidly increase the amplitude. At this time, if you want to protect the centrifugal pump from greater damage, you must immediately stop for inspection.

rotary vane vacuum pump unit of mechanical seal inspection of common sense

Five Advantages of Pipeline Pump

 

The pipeline centrifugal pump is a novel pump developed for pipeline pressurization and transportation to solve the problem of low pipeline pressure. It has great advantages over the horizontal centrifugal pump currently used. The advantages of pipeline pump are mainly reflected in the following points:
1. Pipeline pump is applicable to pressurized water delivery for high-rise buildings, garden sprinkler irrigation, cooling tower water supply, long-distance water delivery, air conditioning, refrigeration washing, bathroom and other cooling systems; Warm water is pressurized circularly, and the operating temperature is below 80 ℃.
2. It is applicable to high-temperature hot water pressurization cycle in heating, boiler and other industries. The operating temperature is below 150 ℃.
3. It is applicable to the transportation of corrosive media in the process flow of food, pharmaceutical, liquor making, chemical and other industries, with the operating temperature below 80 ℃.
4. It is applicable to other industrial sites where there are non corrosive liquids, methane or underground fixed equipment of coal mine Class I, factory Class IIA and IIB, temperature groups T1, T2, T3, T4, and explosive mixtures. The operating temperature is below 80 ℃.
5. The pipeline pump is suitable for conveying corrosive industrial liquids such as chemical, pharmaceutical, petroleum, food, national defense, etc. There are other industrial sites with explosive mixtures in groups T1, T2, T3, T4, such as methane or coal mine underground fixed equipment Class I, factory IIA, IIB. The operating temperature is below 150 ℃.

What is the difference before and after PVD coating?

Centrifugal pump test method and precautions

All newly purchased and installed centrifugal pump products need to be tested in advance after installation. The following centrifugal pump testing methods and precautions should be followed when testing centrifugal pumps
1. Before starting the centrifugal pump, it is forbidden to run the pump with no load and no load. The liquid test shall be carried out according to the operating procedures specified in the operating instructions of the centrifugal pump. For the forced lubrication system, the temperature rise of the bearing oil of the centrifugal pump shall not exceed 28 ℃, and the temperature of the bearing metal shall be less than 93 ℃.
2. For centrifugal pump of oil ring lubrication or splash lubrication system, the temperature of lubricating oil shall not exceed 39 ℃, and the temperature of bearing parts shall be less than 82 ℃.
3. When testing the centrifugal pump, the vibration value of the bearing of the centrifugal pump should also be checked. The vibration standard of the bearing of the centrifugal pump can refer to the vibration standard of the relevant petrochemical rotating machinery.
4. During the test run of centrifugal pump, the operation of centrifugal pump shall be very balanced and noiseless, the coolant and lubricating oil system shall be normal, and the centrifugal pump and auxiliary pipeline shall be free of leakage.
5. During the test run of the centrifugal pump, attention should be paid to whether the current of the motor of the centrifugal pump operates within the specified range. If the current exceeds the specified range, it means that the head under the actual working condition is lower than the pump head. At this time, it is recommended to turn down the outlet valve to control the flow of the centrifugal pump so that its current can be used within the rated current range.
6. Various seals and medium leakage of centrifugal pump shall not exceed the following standard requirements:
(1) Clean water centrifugal pump with mechanical seal: light oil 10 drops/min, heavy oil 5 drops/min
(2) Multi stage centrifugal pump products with packing seal: light oil 20 drops/min, heavy oil 10 drops/min
(3) For the magnetic drive pump to transport toxic, harmful, flammable and explosive media, no visible leakage is allowed.

Vacuum System Evacuation, Heating and Exhaust Technology to Introduction

What should be paid attention to during maintenance of multistage centrifugal pump

 

If conditions permit, it is better to read the manufacturer's maintenance instructions and general assembly drawings first to see what special points need attention.
1、 During disassembly:
1. Before removing the thrust bearing, measure the clearance of the balance disc with a dial indicator and make records;
2. When disassembling the multistage pump, all parts must be marked according to the original assembly sequence to avoid confusion and wrong installation during reassembly;
3. Small parts (such as keys) that are not convenient for marking can be put together with impellers or guide vanes (middle section) at the same level.
4. During disassembly, you can visually feel whether there are abnormal parts, such as loose fit.
2、 Parts maintenance:
1. Visually check whether the surface of each part is normal, and all mating surfaces must be free of bumps, scratches, rust, etc;
2. Use measuring tools to measure whether the tolerance of key mating parts is qualified;
3. Measure whether the clearance of impeller seal ring, housing seal ring, guide vane seal ring, interstage shaft sleeve, etc. is within the tolerance range, and replace them if they are excessively worn;
4. Check whether the bearing is in good condition;
5. All sealing rings and gaskets shall be replaced if they are superior;
3、 Reinstallation:
1. First install the rotor and conduct dynamic balance test again;
2. Reassemble all parts in the reverse order of pump disassembly. During reassembly, pay attention to the clearance value of each seal ring again to ensure that it is correct;
3. Before installing the balance disc, measure the total rotor runout;
4. After installing the balance disc, measure the rotor half run.
5. Compared with the total string quantity and half string quantity required on the general assembly drawing of the manufacturer, they should basically meet the drawing requirements. Generally, the half string quantity is about half of the total string quantity.
6. Tighten all the main bolts evenly and diagonally;
7. Draw a dial indicator on the shaft, and rotate the shaft to mark the balance disc. The tolerance shall be in accordance with the drawing requirements and generally shall not exceed 0.06;
8. When installing the thrust bearing, pay attention to adjusting the clearance of the balance disc, and use the adjusting ring in front of the bearing to adjust the clearance of the balance disc to the drawing requirements.

vacuum pump of aluminum wire motor and copper wire motor difference between of comparison

Introduction to mixed flow pump

1、 Type of mud flow pump
Mixed flow pump is a kind of pump between centrifugal pump and axial flow pump. Its lift is suitable
Medium. With large flow and wide application scope, it is a good pump type in plain river network areas and hilly areas.
According to the difference of outlet chamber of gear pump, diaphragm pump has volute type and guide vane type.
The volute type mixed flow pump can be divided into horizontal type and vertical type, among which the horizontal type is more widely used; Guide vane mixing
There are also two types of sulfur pumps: horizontal and vertical. The vertical mixed flow pump is similar to the vertical axial flow pump
Medium and small mixed flow pumps, most of which are of chip expansion volute type, and large mixed flow pumps are of guide vane type.
Like axial flow pump, the pr plate of mixed flow pump is generally fixed, but large guide vane mixed flow pump
The blade pairs of are made into fully adjustable ones. According to the needs of operation, the blade can be adjusted at any time
Installation angle to expand its high efficiency operation range.
2、 Structure of mixed flow pump
Compared with centrifugal pump and axial flow pump, mixed flow pump has low lift and large flow, so the impeller
The shape is quite special. Since the difference between the inlet diameter and the outlet diameter of the impeller is small, the flow passage
The ratio of width to outlet diameter is relatively large, so the relative width of volute is greater than that of centrifugal pump
Large. The blade is in a throw curve form from the inlet to the outlet, and the edge of the blade outlet is inclined, resulting in
Centrifugal force and thrust, the direction of water flowing out of the impeller is neither radial (such as centrifugal force
Pump) is not axial (such as uranium flow pump), but is inclined between them, so mixed flow pump
Also called diagonal flow pump. The shape of the mixed flow system impeller is shown in Figure 5. Low specific speed impeller
It is closed, with front and rear cover plates, similar to the impeller of centrifugal pump; High specific speed. L round is open
Type, similar to axial flow pump.

vacuum pump oil change for precautions