The Selection Principle and Precautions for Magnetic Drive Pumps
When selecting and designing a magnetic drive pump, the user will first determine the use and performance requirements for the pump equipment in the production device, and select the type of magnetic drive pump accordingly. This selection method first starts with the selection of the type and form of the pump, and select the magnetic drive pump according to the selection principle and basis.
The selection principle and precautions for magnetic drive pumps
(1) According to the needs of production, when a magnetic drive pump is chosen, it should fully meet the requirements for flow rates and heads in the production process. Make the type and performance of the selected magnetic drive pump meet the requirements for process parameters such as flow rates, heads, pressure, temperatures, cavitation margin and suction. Choose pumps that have good performance, match the flow and head required by the project and have good adaptability and assurance to process changes, mainly from the following aspects:
① From the finalized series of products, a magnetic drive pump with high efficiency, good suction performance and wide ranges of use should be selected. When there are multiple pump types to choose from, economic and technical analysis should be carried out and the best one should be adopted.
②When the series of pumps cannot meet the selection requirements, new pump products can be designed and trial-produced according to the prescribed procedures. When the project requires a great head change, the H-Q curve steep drop pump should be selected; when the project requires a great flow change, the H-Q curve flat pump should be selected. The selected pump should be used as much as possible to operate within its range, that is, near the design (rated) operating point. The newly designed and trial-produced magnetically drive centrifugal pump under various working conditions should enable the unit to have safe operation without cavitation, vibration and overload.
(2) The requirements for media characteristics must be met. Magnetic drive pumps transporting flammable, explosive, toxic, harmful, strongly corrosive or precious media require reliable static sealing. It is required to adopt corrosion resistant materials for all pressure bearing flow parts for magnetic drive pumps that transport corrosive media. For magnetic drive pumps conveying media with a few solid particles, wear resistant materials are required for all pressure-bearing flow parts.
(3) The selected magnetic drive pump should have average high efficiency, low energy consumption and low operating costs during long-term operation.
(4) Economically, equipment costs, operating costs, maintenance costs and management costs should be taken into account to minimize the total cost. The type and number of pumps selected should make the investment of the entire system economical and save investment costs.
(5) The magnetic drive pump should have good mechanical reliability, low noise, low vibration, easy construction, operation, management and maintenance.
(6) For stepped pumps, the type and number of pumps should meet the flow coordination requirements between the upper and lower pumps, and try to avoid insufficient or excessive flow of the lower pumps due to improper flow coordination.
(7) The quality of the magnetic coupling material is related to the service life and reliability of the pump, and the price of a single magnetic coupling material is high. Therefore, the material of the magnetic coupling, supplier and its performance index should be indicated when an order is placed. In addition, the material and service life of the sliding bearing should also be noted.
(8) In order to ensure the quality of the project, it is generally not advisable to entrust domestic manufacturers to research or develop pumps that exceed the product parameter range to ensure the quality and progress of the project.
(9) The temperature of the conveying medium should be controlled between -75 and 450 degrees Celsius.
(10) The viscosity of the conveying medium should be less than 100mPas.
(11) The content of solid particles in the conveying medium should not exceed 8% of the total volume of the medium, and the particle size should be less than or equal to 40 μm.
(12) There is no evacuated vaporization of the medium at the pump inlet.
(13) The motor power is generally less than 160KW.
The selection principle and precautions for magnetic drive pumps
(1) According to the needs of production, when a magnetic drive pump is chosen, it should fully meet the requirements for flow rates and heads in the production process. Make the type and performance of the selected magnetic drive pump meet the requirements for process parameters such as flow rates, heads, pressure, temperatures, cavitation margin and suction. Choose pumps that have good performance, match the flow and head required by the project and have good adaptability and assurance to process changes, mainly from the following aspects:
① From the finalized series of products, a magnetic drive pump with high efficiency, good suction performance and wide ranges of use should be selected. When there are multiple pump types to choose from, economic and technical analysis should be carried out and the best one should be adopted.
②When the series of pumps cannot meet the selection requirements, new pump products can be designed and trial-produced according to the prescribed procedures. When the project requires a great head change, the H-Q curve steep drop pump should be selected; when the project requires a great flow change, the H-Q curve flat pump should be selected. The selected pump should be used as much as possible to operate within its range, that is, near the design (rated) operating point. The newly designed and trial-produced magnetically drive centrifugal pump under various working conditions should enable the unit to have safe operation without cavitation, vibration and overload.
(2) The requirements for media characteristics must be met. Magnetic drive pumps transporting flammable, explosive, toxic, harmful, strongly corrosive or precious media require reliable static sealing. It is required to adopt corrosion resistant materials for all pressure bearing flow parts for magnetic drive pumps that transport corrosive media. For magnetic drive pumps conveying media with a few solid particles, wear resistant materials are required for all pressure-bearing flow parts.
(3) The selected magnetic drive pump should have average high efficiency, low energy consumption and low operating costs during long-term operation.
(4) Economically, equipment costs, operating costs, maintenance costs and management costs should be taken into account to minimize the total cost. The type and number of pumps selected should make the investment of the entire system economical and save investment costs.
(5) The magnetic drive pump should have good mechanical reliability, low noise, low vibration, easy construction, operation, management and maintenance.
(6) For stepped pumps, the type and number of pumps should meet the flow coordination requirements between the upper and lower pumps, and try to avoid insufficient or excessive flow of the lower pumps due to improper flow coordination.
(7) The quality of the magnetic coupling material is related to the service life and reliability of the pump, and the price of a single magnetic coupling material is high. Therefore, the material of the magnetic coupling, supplier and its performance index should be indicated when an order is placed. In addition, the material and service life of the sliding bearing should also be noted.
(8) In order to ensure the quality of the project, it is generally not advisable to entrust domestic manufacturers to research or develop pumps that exceed the product parameter range to ensure the quality and progress of the project.
(9) The temperature of the conveying medium should be controlled between -75 and 450 degrees Celsius.
(10) The viscosity of the conveying medium should be less than 100mPas.
(11) The content of solid particles in the conveying medium should not exceed 8% of the total volume of the medium, and the particle size should be less than or equal to 40 μm.
(12) There is no evacuated vaporization of the medium at the pump inlet.
(13) The motor power is generally less than 160KW.
