Pump selection principle
1. Make the type and performance of the selected pump meet the requirements of process parameters such as device flow, head, pressure, temperature, cavitation margin, and suction.
2. Must meet the requirements of medium characteristics
For pumps that transport flammable, explosive, toxic or precious media, reliable shaft seals or non-leakage pumps are required, such as magnetic drive pumps (no shaft seal, isolated magnetic indirect drive).
For pumps that transport corrosive media, the convection parts are required to use corrosion-resistant materials, such as fluoroplastic magnetic pumps.
For pumps that convey solid particles, the convection parts are required to be made of wear-resistant materials, and the shaft seal should be flushed with clean liquid when necessary.
3. The mechanical aspect requires high reliability, low noise and low vibration.
4. Calculate the input cost of pump purchase correctly, inspect the pump manufacturer, and require that its equipment be of good quality, good after-sales service, and spare parts can be supplied in time.
1. Prevent particles from entering
(1) When transporting media containing solid particles, filter at the inlet of the pump flow pipe.
(2) After transporting the medium that is easy to crystallize or precipitate, flush it in time (pour clean water into the pump cavity after stopping the pump, and drain it after 1 min of operation) to ensure the service life of the sliding bearing;
(3) Ferromagnetic impurities and particles are not allowed to enter the magnetic drive and bearing friction pairs;
2. Prevent demagnetization
(1) The magnetic torque cannot be designed too small;
(2) It should be operated under the specified temperature conditions, and the medium temperature is strictly prohibited. A platinum resistance temperature sensor can be installed on the outer surface of the magnetic pump isolation sleeve to detect the temperature rise in the annulus area, so as to alarm or shut down when the temperature exceeds the limit.
3. Prevent dry friction
(1) Idling is strictly prohibited;
(2) It is strictly forbidden to evacuate the medium;
(3) When the outlet valve is closed, the continuous operation time of the pump shall not exceed 2min to prevent the magnetic actuator from overheating and failing.
4. Not usable in stressful systems
Because there is a certain inter-system in the pump cavity of the magnetic pump and the "static bearing" is used in the magnetic pump, this series of pumps must not be used in a pressured system, and neither positive pressure nor negative pressure is feasible.
(1) Because the cooling and lubrication of the magnetic pump bearings rely on the conveyed medium, idling is absolutely prohibited, and at the same time, avoiding idling operation caused by restarting after a power cut in the middle of the work.
(2) If the conveyed medium contains solid particles, a filter should be added to the pump inlet: if it contains ferromagnetic particles, a magnetic filter should be added.
(3) When the pump is in use, the ambient temperature should be less than 40℃, and the temperature rise of the motor should not exceed 75℃.
(4) The conveyed medium and its temperature should be within the allowable range of the pump material. The operating temperature of the engineering plastic pump is <60℃, the operating temperature of the metal pump is <100℃, the suction pressure is not more than 0.2MPa, the maximum working pressure is 1.6MPa, the density is not more than 1600Kg/m3, and the viscosity is not more than 30X10-6m2/S. Liquid containing hard particles and fibers.
(5) For the medium that is easy to precipitate and crystallize, the transport fluid should be cleaned in time after use to drain the liquid accumulation in the pump.
(6) After 1000 hours of normal operation of the magnetic pump, the wear of the bearing and end face moving ring should be disassembled and inspected, and the wearing parts that are not suitable for reuse should be replaced.
Saiken Pump Industry is a manufacturer and seller of oil pumps in China
