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Pump as the most common equipment in industrial production, in today's high-demand occasions, the use conditions are also getting higher and higher. Canned pumps are used more and more widely in chemical plants because they can be absolutely leak-free without rotating shaft seal. Some people ask, then shield pump, magnetic pump and centrifugal pump in what areas are different? In this issue, we will focus on you.


The fully sealed, or leak-free structure of the canned pump makes it most suitable for pumping flammable, valuable, corrosive and toxic liquids. Because the shield pump is leak-free, it is helpful to the safety of flammable liquid system, and has more prominent economic effect for precious and corrosive liquids.


Differences of Canned Pump


1. Integrative structure of motor and pump, coaxial connection of pump and motor;


2. The inner side of the stator and the outer side of the rotor of the motor have a shielding sleeve, and the inner side of the shielding sleeve is connected with the pump.


3. Installation modes are divided into horizontal and vertical modes.


4. The cooling fan of the motor is cancelled, and the motor is cooled by circulating medium between the stator and the rotor. At the same time, the surface of the motor base is cooled.


Advantages of Canned Pump


1. Fully enclosed. There is no dynamic seal in the structure, only static seal in the shell of the pump, so it can be completely leak-free, especially suitable for conveying inflammable, explosive, precious and toxic, corrosive and radioactive liquids.


2. High safety. Each rotor and stator has a shield sleeve to keep the motor rotor and stator away from material. Even if the shield sleeve is broken, there will be no danger of leakage.


3. The structure is compact and occupies less land. Pump and motor system as a whole, disassembly and assembly do not need to find the center. The requirements for the base and foundation are low, and the daily maintenance workload is small, and the maintenance cost is low.


4. Smooth operation, low noise, no need for lubricating oil. Because there are no rolling bearings and motor fans, there is no need for lubricating oil and low noise.


5. Wide range of applications. It can meet the requirements for high temperature, high pressure, low temperature, high melting point and other working conditions.


Shortcomings of Canned Pump


1. Because the shielding pump adopts sliding bearing and is lubricated by the conveyed medium, the medium with poor lubrication should not be conveyed by the shielding pump. Generally, it is suitable for shielding pumps with viscosities of 0.1-20 mPa.s.


2. The efficiency of the canned pump is usually lower than that of the single-end mechanical seal centrifugal pump, but approximately equal to that of the double-end mechanical seal centrifugal pump.


3. When the shielding pump runs for a long time under the condition of small flow rate, the efficiency of the shielding pump is low, which will cause heat and evaporation of the liquid, and cause the pump to run dry, thus damaging the sliding bearing.


Use occasion of canned pump


1. When the pressure condition is abnormal. When the suction side pressure of the pump is high and the difference between the suction side pressure and the discharge side pressure is small, additional stress will be endured if the packing box is used.


2. Where a high vacuum is required. If the packing box is used, when the shaft is slightly eccentric or worn out, air will enter through the packing box.


3. The occasion of alternate operation of vacuum and pressure. Packing box or sealing structure for ordinary vacuum operation can not be used for operation under pressure.


4. The occasions for handling precious liquids. Liquids cause great economic losses.


5. The occasions for handling toxic liquids. And the danger of life. If the packing letter is used, the leakage of toxic liquids will result in human health because of the loss of a considerable amount of valuable value every year, such as the use of packing letter.


6. Where explosive gases occur. Although flammable liquids, such as gasoline, kerosene and jet fuel, can be transported by a centrifugal pump with a rotating seal connected to an explosion-proof motor, leaking liquids and vaporized liquids will make the entire site a dangerous place for explosion.


7. Treatment of radioactive liquids. Radioactive liquids are not allowed to leak from the packing box. In addition, many fillers are not made of materials that can be exposed to radioactive liquids for a long time.


8. Treatment of corrosive liquids. In addition to the local corrosion caused by the leakage of packing box, the process unit will also be eroded by the steam generated by the leakage of corrosive liquid.


9. When handling harmful liquids. When harmful gases such as stench are produced by the leakage of packing box, the bad condition that can not be operated will be formed.


10. In the case of easy-to-react liquids. If the shielding pump is used, the liquid will not be solidified by the pollution of gas, water, filler lubricant and other substances, nor will it crystallize and cause other obstacles.