Reasons for demagnetization of magnetic steel of magnetic pump

During the use of the magnetic drive pump, some users responded that the magnetic steel was demagnetized, resulting in the pump unable to operate normally. Therefore, it is considered to be the quality problem of the magnetic steel delivered by the company. However, after many after-sales analysis, we found that users had some problems in the early design or later use, resulting in demagnetization of magnetic steel. Therefore, in order to reduce the use cost of users and avoid unnecessary losses, let's talk about several major reasons for demagnetization of magnetic steel today.
1. The use temperature is unreasonable. The temperature of the material conveyed by the pump is too high, exceeding the allowable service temperature of the magnetic material. For example, for the pump with Nd-Fe-B magnetic steel, the service temperature should be less than 150 ℃. If the system temperature exceeds 150 ℃, the magnetic steel will be demagnetized soon.
2. Long time low lift operation. For example, if the flow at the rated point is 25 m3 / h and the head is 50 m, if it deviates from the rated point (for example, the head is only more than 10 meters), the return pressure inside the pump will drop, the circulation will be blocked, the eddy current belt of the metal isolation sleeve will not go, its temperature will rise sharply, and the magnetic steel will demagnetize.
3. Pipeline matching is unreasonable. For example, DN65 pipeline is required at the inlet. If the pipeline is less than 65mm, the flow will be in short supply, which will easily lead to poor internal circulation, heat is not easy to be taken away, and the system temperature exceeds the service temperature of magnetic steel.
4. The sliding bearing is worn and not replaced in time. If it is not replaced in time, there will be friction between the inner magnetic rotor and the inner wall of the isolation sleeve, resulting in the temperature rise of the isolation sleeve and demagnetization of the magnetic steel.
5. The magnetic pump runs idly. In this case, the temperature of the metal isolation sleeve and the inner magnetic rotor rises sharply, exceeding the service temperature of the magnetic steel, which will soon lead to demagnetization of the magnetic steel of the inner magnetic rotor.
6. The inlet and outlet pipelines of the pump are blocked. In this case, the magnetic pump idles, or the internal circulation of the pump is affected and the temperature rises; Moreover, the blockage of the outlet pipeline will also demagnetize the magnetic steel because the internal circulation of the pump cannot be carried out. If the pump inlet pipeline is equipped with a filter, the filter shall be cleaned regularly to ensure that the filtering area is within a reasonable range.
7. Abnormal jamming of rotor parts. The rotor component composed of internal magnet and impeller is stuck by mechanical impurities and cannot run, but the motor does not stop in time, which will lead to demagnetization of magnetic steel.
8. Cavitation. Cavitation of the pump due to various reasons will cause demagnetization of the magnetic steel.

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Safety protection method of submersible pump

Submersible pump is an important equipment for water extraction in deep wells. When in use, the whole unit works in the water and extracts the groundwater to the surface. It is used for domestic water, mine rescue, industrial cooling, farmland irrigation, seawater lifting, ship load regulation, and fountain landscape. Hot water submersible pump is used for bathing in hot springs. It can also be used to extract groundwater from deep wells. It can also be used in water lifting projects such as rivers, reservoirs and canals. It is mainly used for farmland irrigation and human and livestock water in alpine areas. It can also be used for central air conditioning cooling, heat pump unit, cold pump unit, city, factory, railway, mine and construction site drainage. The general flow can reach 5 ~ 650m3 / h and the lift can reach 10-550m. Submersible pumps often burn out motor windings due to lack of water in the pool. In view of this situation, we have sorted out several protection measures for submersible pump today: water shortage protection, motor water leakage protection, oil chamber water leakage protection, insulation resistance protection, winding overheating protection, bearing overheating protection, etc.
1. Abnormal power supply voltage is prohibited
Because the low-voltage power supply line is relatively long, it is common that the terminal voltage of the line is too low. When the phase voltage is lower than 198 V and the line voltage is lower than 342 V, the speed of the submersible pump motor decreases. When it does not reach 70% of the rated speed, the starting centrifugal switch will be closed, causing the starting winding to be energized for a long time, heating and even burning the winding and capacitor. On the contrary, too high voltage causes the motor to overheat and burn out the winding. Therefore, during the operation of submersible pump, the operator must observe the power supply voltage at any time. If it is less than 10% lower than the rated voltage and more than 10% higher than the rated voltage, stop the motor, find out the cause and eliminate the fault.
2. Confirm the correct rotation direction of the motor
The rotation direction of the motor should be clarified. Now there are many types of high head submersible pumps that can discharge water during forward rotation and reverse rotation, but the water output is small and the current is large during reverse rotation. If the reverse time is long, the motor winding will be damaged.
3. Insulation resistance requirements for cable installation and submersible pump
When installing the submersible pump, the cable should be overhead and the power line should not be too long. Do not force the cable when the submersible pump is launched or raised, so as to avoid breaking the power line. Do not sink into the mud when the submersible pump is working, otherwise it will cause poor heat dissipation of the motor and burn out the motor winding. During installation, the insulation resistance of the motor shall not be less than 0.5 megohm.
4. Avoid frequent switching
Do not switch on and off the submersible pump frequently, because the backflow will occur when the electric pump stops running. If it is started immediately, the motor load will start, resulting in excessive starting current and burning out the winding. Due to the large current during startup, frequent startup will also burn out the motor winding of submersible pump.

Vacuum pump used in Milking industry 

What if the water output of single-stage centrifugal water pump equipment is insufficient

When using single-stage centrifugal water pump equipment, the water output is insufficient occasionally. Many people don't know the reason, so they can't find a solution
Due to the vortex generated in the pool and the air sucked into the pump body by the self-priming centrifugal pump, the water output of the pump is insufficient. In case of this phenomenon, the submerged depth of the inlet pipe can be increased, or other measures to prevent vortex can be taken.
The impeller leakage reducing ring of single-stage centrifugal pump is worn too much, resulting in insufficient water output of the pump. Only replace the leakage reducing ring or replace the impeller if necessary. Because the speed of the water pump is too low, for example, the speed of the water pump is required to be 2900r / min, while the motor speed of some users is only 1450r / min. for example, some users of common vertical centrifugal pump products use frequency conversion control. Because the frequency is adjusted too low, the water volume will be reduced accordingly. The solution is to make the water pump power machine reach the standard speed
Because there is air in the water inlet pipe of various pumps, the solution is to reinstall the water inlet pipe of the pump to make the water inlet pipe horizontal or inclined downward.
If the impeller of the water pump is seriously damaged due to cavitation or corrosion, use a new impeller or corrosion-resistant impeller. The opening of the bottom valve of the water pump is too small or the bottom valve, water pump and pipeline are blocked by sundries. At this time, check and eliminate them one by one
If the pump operates for a long time, it is likely that the pump flow will be reduced due to the excessive clearance of the mouth ring, but the change of this amount should not be reduced suddenly, but should be a slow process. If the pump has not been overhauled for a long time, the flow will be reduced but the operation is stable, which is likely to be caused by the wear of the mouth ring, which must be disassembled for inspection. The solution is to reuse the new pump body mouth ring and impeller mouth ring

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How to use heat transfer oil pump correctly

The air-cooled high-temperature heat transfer oil pump is also called heat transfer oil pump, high-temperature heat transfer oil pump and heat transfer oil circulating pump. Its structure and performance make it widely used and popularized in different industries. It can withstand high temperature and has good sealing performance at high temperature. It is a major leap in technology in the oil pump industry.
It is applicable to petroleum and chemical industry, oil industry, synthetic fiber industry, textile printing and dyeing industry, plastic and rubber industry, paper industry, wood industry, construction industry and other industries. In addition, ry high-temperature heat transfer oil pump is also widely used in machinery industry, food industry, pharmaceutical production, oil supply circulation system of hot oil furnace and hot oil heating circulation system. But how to use the heat transfer oil pump correctly to improve its efficiency? Here are some points we can analyze and refer to:
Accurate use method of hot oil pump:
First, after the heat transfer oil pump and pipeline are installed, whether using water pressure or air pressure, the inlet and outlet valves of the heat transfer oil pump must be closed before pressure test, so as to prevent damage to the seals and oil leakage.
Boot preparation
(1) Clean up the site, unscrew the bearing seat screws and add heat transfer oil as lubricating oil
(2) Before start-up, fill the heat transfer oil pump with the heat transfer oil delivered to drive out the air in the heat transfer oil pump. At this time, the gate valve on the pipe at the outlet of Shanghai Zhengao Pump Manufacturing Co., Ltd. shall be closed
(3) The delivered heat transfer oil shall be heated evenly before start-up, and the preheating is carried out by using the delivered heat transfer oil continuously through the pump body Preheating scale: the temperature of the pump shell of the heat transfer oil pump shall not be lower than the inlet oil temperature by 40 ℃, and the preheating speed shall be 50 ℃ / h. during startup preheating, loosen the side nut on the pump foot by 0.3-0.5mm, and tighten it after preheating
(4) When moving the coupling pump by hand, it should roll flexibly

2BE liquid ring pump in mining vacuum filter of application 

Guidance on specific methods of using sewage pump

The whole sewage pump is made of stainless steel to meet the occasions with corrosive medium. It has no blockage, automatic coupling equipment, motor monitoring system and water leakage maintenance function. It is widely used in sewage drainage stations in residential areas. Discharge of thin mud in municipal engineering and construction site. Water supply equipment of waterworks.
Farm sewage discharge and rural farmland irrigation. Supporting exploration mines and water treatment equipment. Instead of carrying people on their shoulders, they suck river mud. Wastewater discharge of enterprises. Urban sewage treatment plant discharge system. Subway, basement, civil air defense system drainage station. Sewage discharge from hospitals, hotels and high-rise buildings.
Jog the motor to see if the motor turns correctly. Start the motor. When the stainless steel blowdown pump works normally, open the outlet pressure gauge and the inlet vacuum pump. After it shows appropriate pressure, gradually open the gate valve and check the motor load together. Try to control the flow and head of the stainless steel water pump within the range indicated on the sign, so as to ensure that the stainless steel water pump works at a higher working efficiency point, so as to achieve greater energy-saving effect.
During the operation of stainless steel sewage pump, the bearing temperature shall not exceed the ambient temperature of 35C, and the higher temperature shall not exceed 80C If the stainless steel sewage pump is found to have abnormal sound response, park immediately to check the reason. Check whether the stainless steel sewage pump, pipeline and joint are loose. Roll the stainless steel water pump by hand to see if the stainless steel water pump is flexible.

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Service conditions and characteristics of pipeline non clogging sewage pump

GW vertical pipeline sewage pump is easy to install and has a wide range of uses. It can be used as a general pipeline pump to supply pressurized water to high-rise buildings. It can also transport sewage containing granular fiber. In addition to conveying sewage, it is also suitable for drainage pump, filtration flushing condensate circulating pump, etc. This series of pumps adopts unique impeller structure and new mechanical seal, which can effectively transport solids and long fibers. Compared with the traditional impeller, the pump impeller adopts the form of single channel or double channel. It is similar to an elbow with the same cross-section size and has very good overcurrent. Equipped with a reasonable worm chamber, the pump has high efficiency. After the dynamic and static balance test of the impeller, the pump has no vibration in operation.
Service conditions of pipeline non clogging sewage pump
A. The service ambient temperature of pipeline sewage pump is ≤ 40 ℃, and the humidity is ≤ 95%; Altitude ≤ 1000m.
B. The medium temperature shall not exceed 60 ℃, and the medium weight shall be 1 ~ 1.3kg/dm3.
C. The application range of cast iron material is pH5 ~ 9.
D. Stainless steel can use general corrosive media.
E. The altitude of the operating environment shall not exceed 1000 meters. If it exceeds the above conditions, it shall be put forward at the time of ordering, so as to provide you with more reliable products.
Note: if the user has special temperature, medium and other requirements, please indicate the details of the transmission medium when ordering, so that the unit can provide more reliable products.
Product features of pipeline non clogging sewage pump
1. The pump and motor are directly connected and coaxial. It is an electromechanical product with compact structure and stable performance.
2. The design of anti clogging hydraulic components with large flow channel greatly improves the dirt passing capacity, and can effectively pass through fiber materials with 5 times the diameter of the pump and solid particles with a diameter of about 50% of the diameter of the pump.
3. The design is reasonable, the supporting motor is reasonable, the efficiency is high, the noise is low, and the energy-saving effect is remarkable.
4. The mechanical seal adopts hard wear-resistant tungsten carbide, which is durable and wear-resistant, and can make the pump operate safely and continuously for more than 8000 hours.
5. The pump is a vertical structure, the inlet and outlet center lines are on the same horizontal line, and the inlet and outlet flanges have the same specifications, which is very convenient for installation and disassembly.
6. The floor area is small and there is no need to build a computer room, which can save a lot of capital construction costs; Add a protective cover at the fan blade end of the motor, and the whole machine can be placed outdoors.

EVP liquid ring vacuum pumps used in mine plant 

How does multistage centrifugal pump balance axial force

The chemical pump balances the axial force through the combination of balance disc and balance drum. The balance disc has axial clearance, and the balance chamber is connected with the inlet by pipeline.
When the rotor of the multi-stage centrifugal pump moves to the inlet end, the axial clearance of the balance disc decreases, the radial clearance of the balance drum remains unchanged, and the chamber pressure between the balance drum and the balance disc increases to balance the increased axial force. This structure overcomes the shortcomings of the balance disc, has small leakage and can automatically balance the axial force.
The thrust bearing is installed behind the radial bearing at the outlet end. It can bear axial forces in two directions, and it can fix the rotor at a certain position. This bearing can bear the additional force or residual axial force generated by the operation of the pump under various abnormal working conditions.
Thrust bearing, for small pumps with small axial force, it is usually a simple and economical method to use thrust bearing to bear axial force. Even if other balancing devices are used, thrust bearings are sometimes installed in consideration of the total residual axial force.
A balance pipe is installed on the pump body of the multi-stage centrifugal pump, and the high-pressure end near the wheel Yi outside the impeller disc is connected with the suction end of the centrifugal pump with a pipe to basically balance the pressure on both sides of the impeller, so as to eliminate the axial force. The advantages and disadvantages of this method are similar to those of the balanced hole method. Some centrifugal pumps are equipped with balance pipe and balance hole at the same time, which can get better balance effect
Double suction impeller is adopted, which makes use of the structural characteristics of the impeller to achieve its own balance. Since the two sides of the double suction impeller are symmetrical, there will be no axial force in theory, but due to the manufacturing quality and the difference of liquid flow on both sides of the impeller, it is impossible to balance all the axial force
Radial rib plate is set on the impeller, and radial rib plate is set outside the impeller disc to balance the axial force. After setting the radial rib plate, the liquid in the high-pressure side of the impeller is driven by the radial rib plate to rotate at a speed close to the rotation speed of the impeller. Under the action of centrifugal force, the liquid pressure in the cavity is reduced, so as to balance the axial force on both sides of the impeller

CL type liquid ring vacuum pump for introduction of lobe purge

Why is the plastic self-priming centrifugal pump always broken

1、 The plastic self-priming centrifugal pump needs to be disassembled and cleaned regularly.
Due to the internal rotation direction of plastic self-priming centrifugal pump and the nature of impurities, a small part will remain in the pump, and impurities are easy to nest between turbine chamber and rotor stator. These dirty things will reduce the water flow of the pump, increase the working temperature and increase the noise.
Therefore, it is recommended to clean the plastic self-priming centrifugal pump once a month, open the protective cover, remove the turbine, rotor and shaft, thoroughly clean the interior, and clean the surface or dead corner with waste toothbrush.
2、 The plastic self-priming centrifugal pump shall not be installed too close to the sand.
Some people like to install the plastic self-priming centrifugal pump close to the bottom. They think that the dirt will be pumped thoroughly. In fact, it is meaningless. As long as the water pump is circulating, the dirt will be pumped into the filter with the water flow.
In addition, do not let the outlet of the plastic self-priming centrifugal pump face too close obstacles, and do not deliberately block the outlet or half of it. These practices will shorten the service life of the plastic self-priming centrifugal pump.

water ring vacuum pump manufacturers by analysis of pipeline leakage methods and measures

Centrifugal pump manufacturers teach you how to disassemble the equipment

The structural forms of different centrifugal pumps are also different, so the disassembly methods are also different. The centrifugal pump manufacturer will show you
Removal of pump cover the manufacturer of centrifugal pump suggests to remove the connecting nut between the pump cover and the pump body first, and then knock the pump cover with a hammer pad and a copper rod to remove it. If there is an ejector bolt, it can be pushed down with the ejector bolt.
For the disassembly of the impeller, unscrew the impeller nut and use a wooden hammer or plumb hammer to gently tap around the impeller to remove it. If the impeller is rusted on the shaft, it can be soaked with washing oil or gasoline before disassembly.
For the disassembly of the pump body, first remove the connecting nut between the pump body and the bracket, and then remove the pump body. Then remove the packing gland and take out the packing in the stuffing box.
For the disassembly of the pump shaft, first remove the pressure bearing covers of the front and rear bearings on the bracket bearing body, and then knock the copper rod from the front direction of the shaft (i.e. towards the coupling direction) to remove the shaft. During the disassembly process, pay attention not to damage the shaft, and the disassembled parts shall be kept in a centralized order.
Remove the connecting bolts between the front and rear bearing bodies before removing the bearing body, and then pull out the bearing bush together with the bearing seat along the axial direction
Remove the packing gland, unscrew the connecting nut between the gland and the pump body, pull out the gland along the axial direction and take out the packing.
Removal of the tail cover: unscrew the connecting nut between the tail cover and the rear section, and then remove the tail cover. Then remove the balance plate and balance plate.
Disassembly of the threaded rod unscrew the nuts at both ends of the threaded rod to pull it out.
For the disassembly of the rear section, tap the rear section with a hammer to loosen it and then remove it.
The impeller can be removed by tapping around the impeller with a wooden hammer or plumb. If the impeller has been rusted on the shaft, it can be soaked with kerosene before dismantling.
For the disassembly of the middle section, gently tap it around the middle section with a hammer to remove it. If it cannot be removed, it can be removed by prying along the two feet of the middle section with a crowbar. After the middle section is removed, the small mouth ring can be removed from it, and the retaining sleeve and guide wing can be removed at the same time. Follow this step by step until the front section (suction section).

Roots pumps of overflow valves 

Model parameters and type selection of pipeline pump

Pipeline pump model, pipeline pump model parameters, pipeline pump selection
1、 Selection of pipeline pump
Pipeline pump refers to the pump products installed in the middle of the pipeline to play the role of pressurization. Generally, pipeline pumps are vertical pipeline pumps. Zui commonly used pipeline pumps are ISG vertical pipeline pumps. This series of vertical pipeline pumps are mainly used to transport clear water medium and can not transport liquids containing particulate impurities. They are mainly made of cast iron and all kinds of stainless steel, If the liquid transported is flammable and explosive, explosion-proof motor and copper impeller shall be selected: explosion-proof pipeline pump can be used. If it is used to transport impurities containing particles, GW sewage pipeline pump should be selected. The impeller of this sewage pipeline pump adopts semi closed impeller, so it can transport all kinds of sewage media. The material is also divided into cast iron and all kinds of stainless steel. In addition, FRP pipeline pump or fluorine lined pipeline pump can be used to transport acid medium.

How often does EVP-200PB series scroll pump replace the sealing strip?

Precautions for selecting asphalt pump

The diaphragm inside the asphalt pump is also made of nitrile rubber, neoprene, fluororubber, polyvinylidene fluoride, polytetraethylene hexaethylene material I according to different liquid media. The selection of asphalt pump shall be considered from the following aspects:
(1) The shape and structure of the valve core are mainly considered according to the selected flow characteristics, unbalanced force and other factors.
(2) When the fluid concentration is high, the valve seat surface will be seriously damaged by friction. Therefore, the flow path of the valve should be smooth and the internal material of the valve should be hard.
(3) As the medium is corrosive, the valve with simple structure shall be selected as far as possible under the condition of meeting the regulation function.
(4) Temperature and pressure of the medium when the temperature and pressure of the medium are high and change greatly, the valve with small temperature and pressure change of the material of the valve core and valve seat shall be selected.
(5) Prevent flash and cavitation. Flash and cavitation are only produced in liquid medium. In the actual production process, flash and cavitation not only affect the calculation of flow coefficient, but also form vibration and noise, which shortens the service life of the valve. Therefore, when selecting the valve, flash and cavitation should be prevented.
2、 Overview of asphalt pump: the asphalt pump is composed of actuator and valve. Using compressed air as the power source, all kinds of corrosive liquids, liquids with particles, high viscosity, volatile, flammable and highly toxic liquids can be pumped and absorbed. It is suitable for various occasions to pump media that cannot be pumped by conventional pumps. Asphalt pump actuators include pneumatic actuators and electric actuators, with models of QBY pneumatic asphalt pump and DBY electric asphalt pump respectively. There are four materials for the main body (valve body) of asphalt pump: plastic, aluminum alloy, cast iron and stainless steel, which are selected according to the requirements of liquid or gas medium. The diaphragm inside the asphalt pump is also made of nitrile rubber, neoprene, fluororubber, polyvinylidene fluoride and polytetraethylene hexaethylene according to different liquid media, so the media type shall be specified when ordering.
3、 Specific selection method of asphalt pump:
The action mode of asphalt pump is selected. The action mode of asphalt pump is only available when the pneumatic actuator is selected. Its action mode is formed by the combination of the positive and negative action of the actuator and the positive and negative action of the valve. There are four types of combination, namely positive (gas off type), positive and negative (gas on type), negative (gas on type) and negative (gas off type). The asphalt pump action modes formed by these four combinations include gas on and gas off. The selection of asphalt pump action mode is mainly considered from three aspects:
(1) Process production safety;
(2) Characteristics of medium;
(3) Product quality and small economic loss.

Liquid ring vacuum pump used in wind tunnel test