Working principle of pipeline pump

Pipeline pump can send water out because of centrifugal force. Before the pump works, the pump body and the inlet pipe must be filled with water to form a vacuum state. When the impeller rotates rapidly, the blades promote the water to rotate quickly. The rotating water flies away from the impeller under the action of centrifugal force. After the water in the pump is thrown out, the central part of the impeller forms a vacuum region. Under the action of atmospheric pressure (or water pressure), the water of Shuiyuan is pressed into the inlet pipe through the pipe network. In this way, continuous pumping can be realized. It is worth mentioning here that the centrifugal pump can be started only after the pump shell is filled with water before starting, otherwise, the pump body will be heated, vibrated, the water output will be reduced, the pump will be damaged (referred to as "cavitation") and the equipment accident will be caused!
There are many types of pipeline pumps. The common classification methods are as follows
According to the impeller suction mode, it is divided into single suction pipeline pump and double suction pipeline pump.
According to the number of impellers: single-stage pipeline pump and multi-stage centrifugal pump.
According to the impeller structure, it is divided into open impeller pipeline pump, semi open impeller pipeline pump and closed impeller pipeline pump.
According to the working pressure, it is divided into low-pressure pipeline pump, medium pressure pipeline pump, high-pressure pipeline pump and vertical pipeline pump.
Five key points for use of pipeline pump:
Test run: check whether the connecting parts are loose; Turn the coupling manually to rotate the rotor for several turns, and check whether the unit rotates flexibly, whether there is sound and uneven weight, so as to judge whether there is foreign matter in the pump or whether the shaft is bent, whether the seal is installed correctly, etc; Check whether the clean No. 20 lubricating oil in the sealing cavity is filled with 1 / 2 of the cavity space; Whether the surface of the pump unit is clean; Unit steering no-load test.
Manual start: fill the pump (for the first time), slightly open the outlet valve and start the motor. When the pressure rises and it is confirmed that the pump unit operates stably, gradually open the outlet valve to the working condition.
Operation inspection: when the pump operates normally at power frequency (frequency conversion), the readings of ammeter, voltmeter, inlet and outlet vacuum gauge, pressure gauge and flowmeter of the pump unit shall be regularly checked and recorded. Whether the vibration, noise and temperature rise of the unit are normal. There shall be no obvious aviation oil leakage at the shaft seal.
Normal shutdown: close the discharge valve to make the pump light load and stop the motor.
Emergency stop condition:
The indication of pump motor working ammeter is abnormal (too large or too few); The pump system makes abnormal noise.
The vacuum pressure gauge at the inlet and outlet of the pump indicate abnormally, the pump body vibrates greatly and makes abnormal noise, and the performance is seriously degraded.
The pump motor produces odor, aviation oil leaks from the shaft seal, and the bearing temperature exceeds 75 degrees.

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Causes of wear of self-priming pump shaft

There are many reasons for the wear of the self-priming pump shaft, but most of them are due to the normal wear of the self-priming pump shaft because it has been used for too long. There are other reasons, of course. For example, it is caused by eccentric wear of the self-priming pump shaft, shaft bending, assembly error, too large centering deviation of the pump rotor and the motor rotor, etc.
Photo of self-priming pump shaft wear causes of self-priming pump bearing wear most of the eccentric wear of self-priming pump shaft is caused by shaft bending, and the wear caused by too loose bearing inner ring or bearing damage at the bearing journal also often occurs. Treatment methods: Hot calibration, cold calibration, mixed calibration, etc.
Most of the shaft bending occurs on multistage centrifugal pumps and submersible pumps because the shafts of these pumps are relatively long. The rotor dynamic imbalance is too large, the rotor vibrates, and the foundation level of the self-priming centrifugal pump is too poor. Another reason is the sagging caused by untimely turning, the temperature difference between the upper and lower parts of the rotor will cause deformation, and the vibration caused by centering deviation when the dynamic imbalance of the rotor is too large.
Self priming centrifugal pump is one of the machines that pump or pressurize liquid. The self-priming pump transfers the mechanical energy or other external energy of the prime mover to the liquid to ensure that the energy of the liquid will increase. It can be mainly used to pump the liquid, including oil, water, emulsion, acid-base liquid, suspended lotion, liquid metal, etc.
Shaft wear often occurs in the long-term operation of non sealed self-priming pump. After analysis, the wear of the self-priming pump shaft is caused by the following reasons.
(1) When assembling the bearing, it is caused by insufficient or no interference between the bearing inner ring and the main shaft.
(2) The alignment deviation between the pump rotor and the motor rotor is too large, and there will be too much vibration during the operation. If the bearing wear is serious, there will even be jamming, resulting in shaft wear.
(3) Compared with the mechanical seal, the traditional packing seal has poor wear resistance and short service life. If the water leakage of the shaft seal increases and the water blocking failure of the water retaining ring causes water inflow of the bearing chamber and bearing damage.
(4) High temperature sintering caused by rapid temperature rise will occur when the bearing is stuck due to lack of oil or oil seal failure suction and the impurities contained in the lubricating oil. When the self-priming pump shaft is worn, the traditional solution is repair welding or machining repair after brush plating. However, there are certain disadvantages in both. The stress generated by repair welding at high temperature cannot be completely eliminated, which is easy to cause material damage. Causing the component to bend or break.
Brush plating is limited by the thickness of the coating, and it is easy to peel off. Both methods need to use metal for repair, which will still cause re wear under the effect of various comprehensive properties. The wear of the self-priming pump shaft can be repaired by using special materials. High temperature will not be generated during repair, which can prevent the influence of repair welding thermal stress, and will not be limited by the unilateral wear of the shaft during repair. This special material can absorb the impact of external force and prevent the possibility of re abrasion.

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Centrifugal pumps are prone to cavitation

Cavitation of centrifugal pump is still a problem difficult to judge accurately, because the typical symptoms of vaporization cavitation are the same as those of the other three cases. This means that when we encounter unique noise and high vibration levels, they may also be caused by inlet or outlet backflow or entrained air, independent of inlet pressure.
1. Inlet return
This situation is caused by various types of instability, such as the combined action of turbulence, backflow and vortex that may occur in the impeller when the pump operates under the condition of small flow. Sometimes referred to as "de flow" or "hydrodynamic" cavitation, these flow patterns will intensify at small flow rates. The flow rate at which this occurs will vary from impeller to impeller.
2. Outlet reflux
Outlet backflow is a similar situation, which may cause pitting damage at the blade tip and sometimes at the volute tongue of (volute pump). It may also be caused by the pump running at a small flow rate.
(3) entrained air
Entrained air contains a variety of situations in which vapor bubbles are already present in the liquid before reaching the pump. When they reach the impeller inlet, exactly the same thing happens, as if they were created at that point. In other words, after reaching the blade, the steam bubble begins to bear the increasing pressure and thus collapses, causing the same damage as cavitation at the same position.
Since the entrained air causes the same pitting damage to the impeller at the same position as the vaporization cavitation, it may cause confusion in fault diagnosis, especially in the same working condition, the two may occur at the same time. However, rapid comparison of npsha and NPSHr, combined with visual inspection of pipe characteristics, is often helpful to determine the root cause of so-called "cavitation" and solve the problem of entrained air.
4. Similarities and differences
Conventional vaporization cavitation, entrained air and reflux cavitation will all lead to pitting damage on the impeller, which is caused by the formation of bubbles and subsequent collapse. The difference between them lies in the method of forming bubbles and the location of the impeller damage caused thereby.
As the severity of all these conditions increases, so will noise, vibration, and impeller damage. Under severe conditions, pitting damage will spread to the entire impeller and may also extend to the pump housing.
Discrimination of cavitation
In general, the big problem is how to determine which of the above three hydraulic conditions is when encountering the common symptoms of noise and vibration.
The flow rate of the pump can be reduced by adjusting the opening of the outlet valve of the pump, and then it can be judged according to the effect of the flow rate change on the noise and vibration. Adjusting the outlet valve of the pump to reduce the flow through the pump will produce three possible situations:
1) The noise and vibration will be significantly reduced or even completely eliminated.
2) Noise and vibration may become more serious.
3) There is little or no change in noise and vibration.

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Horizontal centrifugal pump is selected for air conditioning water circulation pump

Air conditioning water circulating pump The horizontal centrifugal pump runs smoothly: the concentricity of the pump shaft and the excellent dynamic and static balance of the impeller ensure stable operation without vibration.
No leakage: cemented carbide seals of different materials ensure no leakage of different media.
Low noise of air conditioning circulating pump: the water pump supported by two low-noise bearings runs smoothly, and there is basically no noise except for the weak noise of the motor.
Low failure rate: the structure is simple and reasonable. The key parts are matched with * quality, and the working time of the whole machine is greatly improved.
Easy maintenance: easy to replace seals and bearings.
Less land occupation: the outlet can be left, right and upward, which is convenient for pipeline layout and installation and saves space.
Application scope of air conditioning water circulating pump:
1. Air conditioning water circulating pump is used for conveying clean water and other liquids with physical and chemical properties similar to clean water, which is suitable for industrial and urban water supply and drainage
Water, pressurized water supply for high-rise buildings, garden sprinkler irrigation, fire-fighting pressurization, long-distance transmission, HVAC refrigeration cycle, bathroom and other cold and warm water circulation pressurization and equipment matching, with the service temperature T ≤ 80 ℃.
2. The horizontal hot water pump is widely used in: metallurgy, chemical industry, textile, papermaking, hotels and restaurants, etc. boiler hot water pressurization and circulation transmission and urban heating system, with the service temperature T ≤ 120 ℃.
3. Horizontal chemical pump, which is used to transport liquid without solid particles, corrosive and with viscosity similar to water, suitable for petroleum and chemical industry
Industrial, metallurgical, electric power, paper, food and pharmaceutical, synthetic fiber and other departments, the use temperature is - 20 ℃ ~ + 120 ℃.
4. Iswb type horizontal pipeline oil pump is used to transport gasoline, kerosene, diesel and other oil products or flammable and explosive liquids. The temperature of the medium to be transported is
-20～ +120℃。

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How to isolate vibration of underwater pump

For the installation of submerged pumps, especially the newly installed pumps, vibration isolation measures must be taken, and laziness is not allowed, otherwise great vibration and noise will occur during use. When the underwater pump is running, the noise is large, which will damage the equipment and cause noise pollution. Therefore, vibration isolation must be done. How can the underwater pump achieve the effect of vibration isolation?
1. The vibration isolation elements shall be symmetrically arranged according to the central axis of the underwater pump unit. The plane arrangement of the rubber vibration isolation pad can be arranged clockwise or counterclockwise.
2. When rubber vibration isolator is used for vibration isolation installation of non sealing liquid underwater pump unit, steel frame should be set under the base of the pump unit and installed by anchor; Foundation bolts are set in the ground or floor, and the rubber vibration isolator is fixed on the ground or floor after passing through the foundation bolts.
3. Rubber vibration isolation pads are arranged in single layer. If the frequency ratio cannot meet the requirements, multi-layer series arrangement can be adopted, but the number of vibration isolation pads should not be more than five.
4. When the rubber vibration isolation pad is set in series, the steel plate shall be flat, and the vibration isolation pad and the steel plate shall be bonded with adhesive. Rubber vibration isolation pads bonded on the upper and lower layers of galvanized steel plate shall be staggered.
Attention should be paid to these aspects in the design, manufacture, use and maintenance of the submerged pump. Only by following the requirements can vibration and noise be reduced and equipment damage be reduced.
Improvement of mechanical seal of submerged pump
The mechanical seal of the submerged pump has a pair of end faces perpendicular to the rotation axis. Under the action of fluid pressure and compensating for the mechanical external force, the end face of the submerged pump maintains contact with the other end through the cooperation of the auxiliary seal and slides, so as to avoid fluid leakage.
The mechanical seal of the submerged pump is the cause of the rare leakage of the submerged pump. When using the mechanical seal of the submerged pump, various factors of using the mechanical seal of the submerged pump shall be analyzed, so as to ensure the temporary and reliable operation of the mechanical seal.
The shaft end face of the moving ring seal ring of the device and the end face of the sealing gland of the static ring seal ring of the device shall be chamfered and polished to avoid damaging the dynamic ring seal ring during disassembly.
The mechanical seal of the submerged pump is a fine component with high requirements, which has high requirements for design, machining and disassembly quality. When using the mechanical seal, this ensures the temporary and reliable operation of the underwater pump seal.

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Alignment method of horizontal centrifugal pump

Centrifugal pump alignment method, pump alignment method
The purpose of horizontal centrifugal pump alignment is to make the center line of the water inlet and outlet of the horizontal centrifugal pump and the pump axis line completely consistent with the corresponding center line planned during the concrete foundation pouring of the horizontal centrifugal pump, so as to be consistent with the motor or diesel engine.
Take the horizontal double suction centrifugal pump as an example to align the centrifugal pump: take the vertical and horizontal center lines as the standard, draw a mutually vertical intersection center line in the air above the horizontal centrifugal pump equipment, hang two vertical lines on the two lines, and move the horizontal centrifugal pump so that the center line of its inlet and outlet coincides with the vertical line hanging on the axis. See the following diagram for the alignment method of centrifugal pump
During the alignment of the horizontal centrifugal pump, if it is found that the position of the anchor bolt hole is incorrect, or the size of the anchor bolt hole of the horizontal centrifugal pump and the drawing in the attached instruction manual are not aligned, the bolt hole is not aligned with the bolt, or there is no room for movement after alignment, then appropriate measures must be taken, such as increasing the anchor bolt hole of the pump, knocking the bolt, etc., to make the alignment deviation of the horizontal centrifugal pump not exceed the specified value.
The alignment method of single-stage single suction centrifugal pump is the same as the above method. It is OK to align the axis line. It should be noted that the outlet center of the single-stage centrifugal pump should meet the design outlet pipeline installation position

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Sewage source heat pump promotes energy conservation and environmental protection in China

The survey shows that the annual discharge of urban sewage in China can reach about 40 billion tons. With the acceleration of urbanization, the discharge of sewage will continue to increase. According to the experts, about 40% of the low-level waste heat in the city is in the potential urban sewage. The reasonable recovery of this part of low-level heat and the simultaneous recovery and utilization of the water and heat of urban sewage treatment not only realize the recovery and utilization of urban waste heat, turn waste into treasure, but also develop a new renewable and clean energy utilization mode, which opens up a new way for the recycling of urban sewage and low-grade clean energy, which can be said to achieve two goals with one stone.
The research shows that urban sewage has the characteristics of large water volume, suitable and stable temperature, small seasonal variation, warm winter and cool summer, so it can be used as a good low-level renewable energy. The primary sewage source heat pump uses urban sewage as a cold and heat source. According to the characteristics of sewage temperature higher than outdoor temperature in winter and lower than outdoor temperature in summer, the heat energy that is difficult to be directly used in sewage is extracted by heat exchanger, sent to the intermediary, and then transmitted to the heat pump host to form high-temperature water for heating in winter. This system can also be used in reverse for cooling in summer.
Winter heating in northern China depends on coal, oil and natural gas. Heating and environmental protection have become a pair of difficult contradictions. Urban sewage is a rare heat pump cold and heat source in the cold regions of the north. Its temperature is relatively stable all the year round. It is higher than the ambient air temperature in winter and lower than the ambient air temperature in summer. This temperature characteristic makes the sewage source heat pump operate more efficiently than the traditional air conditioning system, and the effect of energy saving and operation cost saving is remarkable. As one of the application forms of the ground source heat pump technology, the promotion of the original sewage heat pump technology is an effective way to change the current situation of the energy consumption structure in cities, which is mainly coal-fired, and it also opens up a new space for the application and development of renewable energy.
Experts introduced the operation mode of the sewage source heat pump air conditioning system, so that the ratio of energy input to output can reach 1:4, that is, the input of 1 kilowatt of electric energy can reach more than 4 kilowatts of heat, saving 30% - 75%. The heating fee is 70% compared with coal-fired heating, 50% compared with gas and 30% compared with oil. When heating, each ton of sewage can obtain 5000-10000 kW of heat energy, which is equivalent to the effective heating value of 1.5kg-3kg standard coal.
The sewage source heat pump system is a cold and heat source for heating in winter, air conditioning in summer and domestic hot water supply throughout the year. The boiler room systems such as coal, gas and oil are omitted for heating, and there is no combustion process, which avoids smoke exhaust pollution. The cooling tower is omitted for cooling, which avoids noise, mold pollution and air pollution of the cooling tower. Do not discharge any waste residue and wastewater into the atmosphere; The exhaust gas and soot have truly realized zero pollution and remarkable environmental benefits.
Under the current situation of global energy crisis and serious environmental pollution, the energy potential contained in urban sewage is huge and it is a clean energy that will not produce pollution. Therefore, the recovery and utilization of low-level energy in urban sewage not only helps to deepen people's comprehensive understanding of the recycling of urban sewage, realize the recycling of resources, turn waste into treasure, and fully reflect the concept of "developing circular economy"; Thus, it can greatly improve the energy utilization rate of the city, reduce the dependence of the city on fossil fuels, and have great practical significance for controlling air pollution, protecting the global environment and building an energy-saving city.
The successful implementation of many projects has proved that the use of primary sewage source heat pump system for heating and cooling has achieved an energy saving rate of 30% ~ 75%, which truly realizes zero emission and zero pollution, and does not discharge any waste gas, waste and waste residue into the atmosphere. Its investment and operation costs are also much lower than those of traditional methods. The vigorous development can save hundreds of millions of tons of coal per year, which will also reduce a large amount of greenhouse gas emissions.
Nowadays, the construction of green ecological civilization has become the focus of common concern of all walks of life. The sewage source heat pump system integrates many highlights such as energy conservation and emission reduction, low-carbon environmental protection, renewable and clean energy utilization, and lays a good foundation for the smooth progress of energy conservation and environmental protection in China.

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Why can't the magnetic pump idle? How to maintain?

Magnetic pump, also known as magnetic drive pump, is mainly made of engineering plastic or stainless steel. It plays an important role in the machinery manufacturing industry. Friends who have used the magnetic pump for a long time know that the magnetic pump cannot idle. Then, why can't it idle? Let's analyze it together today!
Prevent the magnetic cylinder from locking
If you have ever known the structure of the magnetic pump, you must know that the engineering plastic magnetic pump has a magnetic cylinder. What is the cooling of the magnetic cylinder? In fact, it depends on the medium of the magnetic pump. If the magnetic pump is idling, the normal state of the magnetic cylinder will be affected. It may cause the magnetic cylinder to lock, and then cause the magnetic pump to work abnormally.
Limited pump opening
If the magnetic pump wants to operate, it must be lubricated. So, how to lubricate? In fact, it depends on the medium of the magnetic pump. If there is no magnetic pump medium, the magnetic pump will face the problem of difficulty in starting the pump.
High temperature demagnetization
The design and working principle of the magnetic pump are related to the magnetic field, so we must ensure the stability of the magnetic field. When the magnetic pump is in the idle state, the temperature of its core components will rise, and the high temperature will have a certain impact on the magnetic field, and then cause demagnetization. In addition, you should know that the outer magnet assembly and the inner magnet assembly are the main components of the magnetic pump.
Why can't the stainless steel magnetic pump idle? After listening to the introduction of Xiaobian, I think you should have a clear idea. The above is the answer that Xiaobian will bring to you today. No matter what kind of magnetic pump, no matter what kind of equipment, it has a certain service life. If you want to extend the service life, you should timely maintain it in daily life. Then, how to maintain the magnetic pump? First, we should ensure that the magnetic pump is not cut off and there is no impurity in the magnetic pump. If the magnetic pump commits any of the above two taboos, it will cause certain damage to the bearing. Bearing is an important component of the magnetic pump. If it is affected, it will definitely shorten the service life of the magnetic pump. Second, we should pay attention to the proportion of liquid to be transported. If the proportion of liquid to be transported is too large, it will lead to insufficient lift. In addition, the impeller is damaged or there is a certain amount of air in the transmission medium, which also leads to this phenomenon. I hope you can avoid it as much as possible. Third, on weekdays, we should often check the suction pipe of the magnetic pump to see if there is air leakage. Especially when the magnetic pump cannot pump liquid, we should pay more attention to this problem.

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Product features and operating instructions of leakage proof magnetic pump

The anti leakage magnetic pump is applicable to the pumping and circulation of all clean chemical solutions containing acid and alkali components. It is widely used in electroplating, electronics, chemical industry, leather, dyeing and finishing wastewater, and can be used with electroplating filters. What are the characteristics of leakage proof magnetic pumps and how should they be operated?
Features of leakage proof magnetic pump:
• adopt magnetic drive, no shaft seal design, and the pump body is completely sealed.
• FRPP and PVDF materials are used for injection molding, which is suitable for most chemical acid-base liquid transportation.
• impeller and magnet are integrally injection molded, which is not easy to be damaged under high-speed operation and high temperature.
• due to its innovative anti idling design, this pump series is a magnetic pump that operates without water for a long time without damage, thus improving the durability of the product.
• the pump bearing is made of silicon carbide, ceramic and titanium metal, which can meet the needs of different workplaces.
Operating instructions for leakage proof magnetic pump:
1. Confirm the direction during the test run. If the direction is wrong, restart the motor after the motor is completely stopped.
2. If the coupling magnet is demagnetized, please stop the pump within one minute. If the demagnetized state continues to operate, the coupling force of the magnet will be reduced.
3. Please limit the liquid temperature change during startup, shutdown and operation to within 80 ℃.
5. Close the outlet valve during startup. However, it is not allowed to operate for a long time when the outlet valve is closed, and the internal temperature rise will damage the pump.
5. In case of power failure during operation, please cut off the power supply immediately and close the outlet valve.
6. Please observe the following items before starting the operation and after long-term shutdown:
① Clean the inside of the pipeline and the tank before supplying water.
② Please lock the flange interface bolts and foundation bolts.
③ Rotate the motor fan with a screwdriver to check whether it rotates smoothly.
④ After the startup water is poured into the pump, please completely close the outlet valve.
⑤. When the suction condition is press in, first confirm the pressure in the pipeline and then confirm whether the pump is filled with liquid. Rotate the motor fan with a driver to rotate the pump, and discharge the air remaining in the impeller from the exhaust port on the pipeline.
⑥. When the upper suction type is used, the starting water is poured into the pump while the motor fan is rotated with a driver to rotate the pump, and the air remaining in the impeller is discharged from the exhaust port on the pipeline.
⑦. After starting, confirm whether the rotation direction of the motor is correct. The rotation direction shall follow the arrow indication of the pump mark. Please change the wiring when returning in the reverse direction.
7. The pump starts to operate normally. When the pressure gauge reaches the higher pressure of the pump, slowly open the outlet valve until the pressure gauge shows the discharge pressure to be set.
8. The operation time when the outlet valve is closed shall be controlled within 1 minute.
9. When the pump is running continuously, please use the flowmeter to confirm whether the pump is running at the appropriate operating point.
10. When the pump is to be stopped in cold weather, the pump may be damaged due to the freezing of the liquid inside the pump. Please discharge the liquid inside the pump after stopping. If the operation is interrupted only for a time and the internal liquid cannot be discharged, please keep the pump warm with a heater to prevent the internal liquid from freezing.

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How to repair the pump shaft of the magnetic pump

Magnetic pump is a common and widely used pump product. The steel used for the bearing of magnetic pump is high carbon chromium bearing steel. Because the smelting of high-quality bearing steel is through vacuum deoxidation and electromagnetic stirring, and the oxide content is small, it can withstand large contact pressure stress and high variable tensile stress at the same time. After heat treatment, the rolling track hardness of the shaft is 58-62hrc.
If the magnetic pump shaft has cracks or the surface has heavy wear, which will affect the strength of the centrifugal pump shaft, it should be replaced with a new shaft. If the pump shaft is slightly bent or slightly worn, and the hook is pulled, it shall be repaired. Then, what are the repair methods of the magnetic pump shaft?
1. Magnetic pump journal hook and repair after wear
For the pump shaft journal with sliding bearing, if the pump shaft journal is scratched or abraded due to poor lubrication or iron scraps and sand particles brought by lubricating oil, and the journal at the rubber guide bearing is worn, it is generally repaired by plating, copper plating and stainless steel plating, and then processed into standard diameter by car or grinding.
2. Repair of bending of magnetic pump shaft
For the pump shaft with small diameter, the bending part can be padded with copper sheet and straightened by hammering; Screw corrector can be used to straighten the pump shaft with larger diameter and less severe bending.
3. Repair of magnetic pump keyway
If the surface of the keyway is rough and the damage is not serious, it can be polished with a file. If the damage is serious, the old groove can be welded and a new groove can be opened elsewhere. However, the pump shaft with large transmission power must be replaced with a new shaft.
4. Repair of magnetic pump shaft thread
If the thread at the end of the pump shaft is slightly damaged, a mixed file can be used to repair the damaged thread and then continue to use. If the damage is serious, turn the pump shaft end down first, then press a bushing, and thread the bushing; Electric and gas welding can also be used to weld the threads at the pump shaft end, and then turn the threads.

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Main parts of centrifugal pump

 

Centrifugal pump is composed of many parts. According to the working state of each part during operation, it can be roughly divided into three categories
Type: rotating part, fixed part J4: and handover part. Taking the single-stage single suction horizontal centrifugal pump as an example, as shown in Fig. 2.4, the function, composition, structure and material of each part are introduced.
1 impeller (also known as working wheel)
The drum is the main part of the water pump, and even the core part of the water pump. The centrifugal system relies on the high-speed rotation of the impeller
Water is used to realize energy conversion.
The N1 wheel rubber of the centrifugal pump is composed of two circular cover plates. There is a gap between the cover plates. 1: the bent blade will be two in front and back
The two cover plates are connected together, and the space groove surrounded by the two adjacent blades and the front and rear cover plates is generally called the flow of water.
(2) accumulated glaze
The beam rib is used to rotate the pump impeller. It receives power from the prime mover (motor) and drives the impeller to rotate. Thus, the pump
The shaft shall have sufficient torsional strength and rigidity, and its deflection shall not exceed the allowable value; The working speed cannot be close to resonance
The critical speed of the phenomenon. Common materials of pump shaft are carbon steel and stainless steel.
3. Key
The impeller and the pump rail are connected by keys. The chain is commonly known as the connecting piece of rotating parts. 3 in Fig. 2.4 is a centrifugal pump
The usually used flat key can only transmit torque and cannot fix the axial position of the impeller. In large and medium-sized fruits, the leaf
The axial position of the wheel is usually located by the shaft sleeve and the nut of the shaft sleeve.

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Does the stainless steel self-priming pump need a bottom valve?

Stainless steel self-priming pump
(1) Does the stainless steel self-priming pump need a bottom valve?
Generally speaking, there is no need to install a bottom valve. Generally, the inlet of the stainless steel self-priming pump is equipped with a check valve. After the stainless steel self-priming pump is shut down, the liquid in the pump chamber cannot return to the original pool, but is stored in the pump chamber. Therefore, there is no need to add liquid for the second use. However, it does not mean that the stainless steel self-priming pump cannot be equipped with a bottom valve. The effect will be better after the bottom valve is installed, Because if the one-way valve is damaged sometimes, there is still a bottom valve to ensure that there will be no idling, and the installation of the bottom valve will effectively ensure the effective suction of the pump!
(2) Stainless steel self-priming pump with bottom valve?
If the bottom valve is installed, the effect will be better, because if the one-way valve is damaged sometimes, there is still the bottom valve as a guarantee that there will be no idling, and the installation of the bottom valve will effectively ensure the effective suction of the pump! Another special case, however, if the suction height difference is too large, or the diameter of the suction pipe is too large, and the volume exceeds the liquid storage volume in the pump chamber of the stainless steel self-priming pump, it will not work normally. At this time, the bottom valve must be installed to ensure the safety and speed of self-priming.
Therefore, the stainless steel self-priming pump does not need to be equipped with a bottom valve, but it does not mean that the bottom valve can not be installed. After the bottom valve is installed, the suction range of the pump will be more guaranteed, especially for some small stainless steel Self-priming pumps, because the small stainless steel self-priming pumps generally do not have a one-way valve and rely on the vacuum generated in the pump body to achieve the self-priming effect, so the suction effect of the pump will be better after the bottom valve is installed!

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Effective methods to reduce cavitation of centrifugal pump

 

Methods to reduce cavitation of centrifugal pump
1、 Improving cavitation resistance of centrifugal pump
1. Method 1 for reducing cavitation of centrifugal pump
(1) Water pump with double suction impeller. NPSH due to double suction pump Δ HC ratio: NPSH of single stage single suction centrifugal pump Δ HC is small. For pumps with the same speed n and flow Q, double suction impellers shall be used as much as possible.
(2) Appropriately increase the impeller inlet diameter and increase the blade inlet width. When the impeller inlet diameter and blade inlet width increase, the impeller inlet speed and relative speed decrease, which shows that the critical NPSH of the pump decreases. However, at this time, the area of the leakage reduction ring at the impeller inlet increases, the leakage increases, and the volumetric efficiency of the pump decreases.
(3) An inducer is added in front of the impeller. An inducer is arranged in front of the impeller of the centrifugal pump. The inducer operates with the blades of the pump, and the pressure wheel produced by the inducer operates together after being coaxially assembled. The pressure generated by the inducer pressurizes the inlet of the impeller and improves the anti cavitation performance of the pump. However, the performance of the pump will be unstable if the inducer is added. Therefore, further exploration and research are needed.
2. In order to reduce the damage of cavitation to the flow-through parts of the pump and prolong its service life, materials with strong cavitation resistance are often used to improve the cavitation resistance of the flow-through parts. Such as cast manganese, bronze, stainless steel and alloy steel; Or coating or laser spraying the surface of the flow passage part with polymer to resist cavitation damage. In addition, finishing the surface of the flow passage part can improve its smoothness and reduce the harm of cavitation.

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How many meters can a common self-priming pump reach?

The problem of how many meters the suction range of the self-priming pump can reach is what the user wants to know before buying. At present, the suction range of the self-priming pump can reach 9 meters. The self-priming pump products with a suction range of 9 meters include vacuum assisted self-priming pump, domestic tap water self-priming pump and screw self-priming pump. The following is the information about these Self-priming pumps for your reference.
1. Domestic tap water self-priming pump
The commonly used domestic self-priming pump can suck within 9 meters of the suction range, and the self-priming time is within 3 minutes. The voltage of the domestic self-priming pump is 220V, the pump body is made of cast iron, and the impeller is made of copper, which can avoid the phenomenon that the cast iron impeller is rusted and causes the impeller to jam and pollute the water source, and can suck the hot water medium of about 40 degrees. Basically, this self-priming pump can only be used as a home, If it is used under other working conditions, the corrosivity of the liquid and whether the required flow head can meet your needs should be considered. If it can meet your needs, you can also choose this series of self-priming pump products.
2. Screw self-priming pump
Screw self-priming pump is also a domestic self-priming pump. Its main feature is high lift, which fills the disadvantage of low lift of ordinary domestic self-priming pump. The lift of screw self-priming pump can reach 130 meters The material is only cast iron, which is suitable for conveying clean water. The screw self-priming pump is also a self-priming pump with a suction range of 9 meters. Some merchants mark the suction range of 10-26 meters on the nameplate of the screw self-priming pump. In fact, this data refers to the horizontal distance. Many users regard it as the suction height and find that it can not be so high when they buy it back. Therefore, special attention should be paid.
3. Vacuum self-priming pump
The vacuum self-priming pump is an industrial self-priming pump. The flow of this series of self-priming pumps is more than 100 cubic meters. This series of vacuum assisted Self-priming pumps can not only be driven by motors, but also be driven by various brands of diesel engines. They can be installed on various mobile pump trucks for use as flood prevention and rescue pumps. Moreover, they can also use the open impeller structure to transport sewage media containing impurities. The pump body materials include cast iron, stainless steel, ductile iron and other metal products for users to choose, The vacuum system can be enlarged according to the user's requirements, so that the water at a distance of 9 meters can be sucked up within 30-60 seconds. The vacuum assisted self-priming pump can be allowed to idle for a short time. Therefore, the vacuum assisted self-priming pump is a kind of flood prevention and rescue pump product.

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How to avoid the magnetic pump idling? Why does the magnetic pump idle?

As we all know, the magnetic pump cannot be idled. Otherwise, the pump head of the magnetic pump will be damaged. If it is serious enough, the magnetic pump will not work normally. So, how to avoid the magnetic pump idling? Why does the magnetic pump idle? In the following, the editor will tell you the answer.
Insufficient flow
First, if you want to avoid the magnetic pump idling, you must give the magnetic pump sufficient flow. Many situations may lead to insufficient flow of the magnetic pump, such as air leakage of the bottom valve or suction pipe, and low rotation speed of the magnetic drive pump itself. In addition, it is recommended to check the inlet and outlet. If there is some garbage and waste at the inlet and outlet, it will also lead to insufficient flow of the magnetic pump. According to the specific reasons, we should take corresponding solutions. Insufficient flow is one of the main factors causing the magnetic pump to run idle. I hope you can pay attention to it. In addition, I also want to emphasize that some magnetic pumps have been used for a long time, so their impellers will be severely worn, which will also affect the flow of the magnetic pump. In the process of inspection, we can also consider checking the impeller of the magnetic pump to see if it is the situation mentioned by the Xiaobian.
No water injection
Before using the engineering plastic magnetic pump, we must inject a certain amount of water into it to maintain the normal operation of the magnetic pump. Of course, some people are careless and always ignore this problem. Once water is not injected into the magnetic pump, it will make the magnetic pump idle. Empty transfer will cause great damage to the magnetic pump. We must pay attention to this.
Foreign matter stuck at the impeller
In the above, the small editor told you about the impeller. When reading this article, I hope you can distinguish it: what the small editor told you in the above is that the impeller is worn, and what I want to emphasize here is that there is foreign matter stuck in the impeller. If there are foreign matters stuck at the impeller, the working efficiency of the impeller will be reduced accordingly. At the same time, when the magnetic pump is working, we can also hear some noise that we could not hear before. In order to avoid idling of the magnetic pump, it is recommended that you carefully check the impeller to see if there is any foreign matter before allowing the magnetic pump to operate, and timely clean the garbage at the impeller in daily life.

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Comprehensive analysis of mortar pump of secondary structural column

Origin of secondary structural column pump: because the secondary structural column pump has complete functions and wide uses, it is a new type of secondary structural column delivery pump, pouring pump and feeding pump. I Product introduction: the secondary structure pouring machine is specially designed to solve the problems of labor-consuming, laborious and low production efficiency in the secondary structure construction. 3. The piston adopts imported raw materials, and the oil cylinder seal and key electrical components adopt imported components. 4. The layout of the secondary structural column hydraulic pouring pump is reasonable and the maintenance space is large. Rigorous research and invention, taking into account economy and reliability, good quality and low price. The secondary structural column pump is mainly used for indoor secondary pouring construction, consolidation grouting and backfill grouting works of construction projects. It is a very useful concrete equipment. Sometimes, the problem of pipe blockage will be encountered during use. Find out the cause of blockage and make reasonable solutions.
This kind of pump can improve the construction efficiency dozens of times. It is an indispensable part of the building. The next 20 years will still be the golden development period of small secondary structure concrete pump. However, market competition and industry competition will become more and more fierce. Enterprises with a certain scale and strength should improve their innovative thinking and innovation ability, especially to constantly improve the level of production and manufacturing modernization, enhance the competitiveness of enterprises in the industry and lead the development of the industry. The small secondary structure concrete pump is a new type of multi-functional construction machinery developed on the basis of absorbing advanced technologies at home and abroad. The product has a wide range of uses, and can be used for building mortar transportation, geotechnical engineering grouting, tunnel construction and large-area spraying. It is easy to operate, safe and reliable, easy to maintain, compact in structure and flexible in movement. This product adopts cam type rotation. Small secondary structural column fine stone conveying pump equipment is small in size, easy to move, economical and practical, and high in efficiency. It fills the blank of structural column pouring mechanization Mobile small-scale concrete delivery pump is a special equipment for structural column pouring. It is exquisite in design, convenient in movement, can be poured on the floor, simple in operation, convenient in use, time-saving and labor-saving. It is the preferred product for structural column pouring. It is suitable for high-rise fine aggregate concrete transportation and building floor group structural column pouring.
The cutting ring adopts the structure that can automatically compensate the gap. The control mode is electro-hydraulic control, with perfect electro-hydraulic overload protection and instrument display system; With reverse pump operation function, it is easy to eliminate the blockage fault; The pumping speed can be adjusted to meet the requirements of various working conditions. The centralized lubrication system automatically controls the start-up, stop and operation time by the program, effectively extending the service life of the rotating parts. (1) The use power of the pump is very small, only 22KW. In the case of no power supply, only one * small generator can work. (2) It is a small concrete delivery pump in China, and is the * choice for many narrow construction environments. (3) The pump is light in weight and easy to move. (4) The pump has high configuration, full hydraulic operation, stable performance, compact structure, low failure rate and long service life. (5) The pump is affordable. There are three configurations for customers to choose: Micro mortar pump, micro fine aggregate concrete pump and small concrete pump. (6) Equipped with variable radial plunger high-pressure pump, the pump delivery pressure is high. The product adopts hydraulic slurry feeding and double cylinder reciprocating operation of vibrating screen filtration, which is fully capable of conveying all kinds of mortar and fine aggregate concrete in building applications. The product has the characteristics of large displacement, high pressure, labor and material saving, flexible movement and so on. It is an ideal mortar conveying equipment. The secondary structural column pump can meet the different requirements of many users for the discharge speed; Advanced wireless function: improve the distance, facilitate the operation, and make the product more humanized; High wear-resistant concrete cylinder: it ensures and increases the service life of the concrete pump and reduces the maintenance cost of the user; The main cylinder with chrome plating on the inner hole of the new process avoids the problem of damage to the main cylinder due to dirty oil.

A Complete Solution To The Failure Causes Of Various Sealing Methods If Pump Happen Leakag

Self priming sewage pump maintenance skills

The self-priming sewage pump mainly includes inlet connecting pipe, one-way valve, outlet connecting pipe, pump body, impeller, mechanical seal, bearing seat and pump shaft. Double blade impeller structure is adopted to improve the dirt passing capacity. The mechanical seal adopts a new friction pair and operates in the oil chamber for a long time. Compact structure, small volume, low noise, remarkable energy saving effect, convenient maintenance and replacement. The automatic control cabinet can automatically control the start and stop of the pump according to the required changes. It does not need to be supervised by special personnel, and it is convenient to use. The installation method can be provided according to the user's needs, so that people do not need to enter the sewage pit during installation. It can be used within the design range to ensure that the motor is not overloaded. The pump is equipped with an outdoor motor and can be directly installed outdoors without building a pump room.
Maintenance skills of self-priming sewage pump:
First of all, check whether the parts are abnormal regularly. If there is any abnormality, refer to the instructions or other materials for inspection. If necessary, replace the parts. Check whether the pipeline and joint of self-priming pump are loose. Rotate the self-priming pump with hands or tools to see if the sewage pump is flexible.
Second, try to control the flow and head of the self-priming pump within the range indicated on the label to ensure that the self-priming pump operates at the highest efficiency point, so as to obtain the maximum energy saving effect.
Third, during the operation of the self-priming pump, the bearing temperature shall not exceed the ambient temperature of 35C and the maximum temperature shall not exceed 80C.
Fourth, if any abnormal sound is found in the self-priming pump, stop the pump immediately to check the cause.
Fifth, when the sewage pump is to be stopped, first close the gate valve and pressure gauge, and then stop the motor.
Sixth, when the self-priming sewage pump is not used for a long time and is used in the cold winter season, after shutdown, it is necessary to unscrew the drain plug at the lower part of the pump body to drain the medium. Prevent frost cracking (if it is sewage, please clean the pump chamber with clean water).
Seventh, when the self-priming sewage pump is not used for a long time, it should be cleaned and hoisted to a ventilated and dry place, and attention should be paid to anti freezing. If it is placed in water, it shall be operated for at least 30min every 15 days (dry grinding is not allowed) to check its function and adaptability.
Eighth, the cable shall be inspected at least once a year. If it is damaged, please replace it.
Ninth, carefully listen to whether the running sound of the motor is abnormal. Because the machine room is noisy during operation, you can listen to both ends of the motor with the help of auxiliary tools such as a screwdriver or a listening stick. If you listen regularly, you can not only find the bad vibration of the motor and its driving equipment, but also judge the amount of internal bearing oil, so as to make timely measures such as adding bearing oil or replacing new bearings, Prevent the motor bearing from being blocked due to lack of oil and dry grinding, running out of the outer circle and burning out during cleaning.
Tenth, after the operation of the self-priming sewage pump fails, please remove it according to the given troubleshooting method. If it still cannot be solved and the cause cannot be determined, do not dismantle or repair it without permission, and immediately find a special person to repair it.

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What are the working characteristics of concentrated sulfuric acid horizontal chemical pump?

At present, many enterprises begin to use concentrated sulfuric acid horizontal chemical pumps for the transportation of various materials. In the actual use process, this high-quality product has won high praise from many enterprise users. However, although many users often use this product, they still know nothing about the functions of the product. So let's take a look at the main working characteristics of the excellent concentrated sulfuric acid horizontal chemical pump?
1. Characteristics of good trafficability
The easy-to-use concentrated sulfuric acid horizontal chemical pump is very quiet during operation. Unlike other water pump products, it cannot achieve the purpose of transmission through internal rotating parts. Therefore, this product has good trafficability when conveying materials. It can pass through the diameter of materials to nearly one centimeter. At the same time, in the process of operation, its own wear is small and will not cause damage to the transported materials. It is especially suitable for transporting viscous sludge and has a short service life.
2. Strong self absorption
Because many users need strong suction to absorb materials when using concentrated sulfuric acid horizontal chemical pump, the manufacturer has specially strengthened the self-priming ability of the product when producing this product. This product has strong self-priming ability, and will not damage the pump body even if it is dry for a long time. Once the pump body exceeds the load, it will automatically stop working, with good self-protection function.
3. Features of high security
In recent years, the reason why the high-quality concentrated sulfuric acid horizontal chemical pump has been sincerely welcomed by many users is that the pipeline of this product is very spacious and suitable for conveying high viscosity products containing particles. At the same time, the concentrated sulfuric acid horizontal chemical pump has high sealing performance, will not pollute the environment when transporting volatile and corrosive substances, and has high safety.

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Desulfurization pump power seal and packing seal

Common desulfurization pumps include fluorine lined centrifugal pumps, mortar pumps, stainless steel pumps, etc. the seals include mechanical seals, power seals, double face seals and packing seals, etc. What is the role of these seals?
1. Packing seal
Put the compressible and resilient packing into the stuffing box, and convert the axial compression force of the gland into radial sealing force, so as to play a sealing role. This sealing method is called packing sealing, and this packing is called sealing packing. Packing seal is widely used in pump design because of its simple structure, convenient replacement, low price, wide adaptability to speed, pressure and medium. When transporting normal temperature media, the packing seal is generally equipped with a packing ring, which is either connected with the high-pressure chamber of the pump or externally connected with a certain pressure of liquid media, which can play the role of cooling, lubrication, sealing or flushing.
As the packing seal is a contact seal, there must be friction and wear problems. The size of friction and wear mainly depends on the compression force of the packing gland. High pressure can improve the sealing effect, but it will increase the power consumption and wear of the shaft sleeve, otherwise it will produce large leakage. Therefore, the pressing force of the gland should be adjusted according to the leakage volume and the temperature of the leaking medium, and the packing should be replaced or supplemented if necessary. The reasonable leakage of packing seal is generally 10-20ml/min. When introducing liquid from the outside, it should be ensured that this liquid has good chemical stability, which will not pollute the medium delivered by the pump, nor react with the medium to produce sediment and solid particles. It should also have good impregnation and lasting retention with the filler, so as to have a good and lasting sealing effect.
2. Power seal
When the auxiliary impeller plus parking seal pump is running, the pressure head generated by the auxiliary impeller balances the high-pressure liquid at the outlet of the main impeller, so as to realize sealing. During shutdown, the auxiliary impeller does not work, so the shutdown sealing device must be equipped at the same time to solve the possible leakage during shutdown.
The sealing structure of the auxiliary impeller is simple, reliable, long service life, and no leakage can be achieved during operation. Therefore, it is often used in pumps conveying media containing impurities. The good sealing effect of the auxiliary impeller is conditional, that is, the working pressure is not allowed to exceed the allowable working pressure. Once exceeded, serious leakage will occur. The main reason for the change of working pressure is the pressure change at the suction port of the pump. Therefore, for the pump with auxiliary impeller seal, strict regulations must be made on the inlet pressure of the pump, otherwise the seal will fail. Due to many forms of parking seals, it is easy to find them after failure, so this article will not repeat it.

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Working principle of acid and alkali resistant self-priming pump

Acid and alkali resistant self-priming pump can achieve the effect of exhaust and irrigation of inlet pipeline with the help of its own device characteristics without irrigation before starting. Self priming pump is divided into the following categories according to the action principle:
1. Gas liquid mixing type (including internal mixing type and external mixing type);
2. Water ring wheel type;
3. Jet type (including liquid jet and gas jet)
Working process of air-water mixed self-priming pump: due to the special structure of the self-priming pump body, after the pump stops running, there is a certain amount of water in the pump body. After the pump is restarted, due to the rotation of the impeller, the air and water in the suction pipe are fully mixed and discharged into the air-water separation chamber. The air and water overflow from the upper part of the chamber, and the water in the lower part returns to the impeller, and is mixed with the remaining air in the suction pipe again, until all the gas in the pump and suction pipe is discharged to complete self-priming
Self priming non clogging sewage pump is applicable to chemical, petroleum, pharmaceutical, mining, papermaking, fiber, pulp, textile, food, power plant and municipal sewage projects, sewage discharge of public facilities, pond aquaculture and other industries
The acid and alkali resistant self-priming pump flows in the direction of rotation. Then it combines with the water from the right return hole and flows along the volute As the liquid constantly impacts the cascade in the volute and is constantly broken by the impeller, it is strongly stirred and mixed with the air to generate a gas water mixture, which flows continuously, so that the gas and water cannot be separated. The mixture is stripped by the tongue at the volute outlet and enters the separation chamber along the short pipe In the separation room, the air is separated and discharged by the outlet pipe, while the water still flows to the outer edge of the impeller through the left and right return holes, and is mixed with the air in the suction pipe. Such repeated circulation gradually exhausts the air in the suction pipe, so that the water enters the pump to complete the self-priming process
Working principle of acid and alkali resistant self-priming pump:
Fill the pump casing with water before starting the pump (or there is water in the pump casing itself) After starting, the impeller rotates at a high speed to make the water in the impeller channel flow to the volute. At this time, a vacuum is formed at the inlet, so that the water inlet check valve is opened, and the air in the suction pipe enters the pump and reaches the outer edge through the impeller channel Self priming pump is a self-priming centrifugal pump, which has the advantages of compact structure, convenient operation, stable operation, easy maintenance, high efficiency, long service life, and strong self-priming capacity. There is no need to install the bottom valve in the pipeline, and it is only necessary to ensure that a certain amount of liquid is stored in the pump before work. Self priming pumps of different materials can be used for different liquids

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