The function of the diaphragm pump in the process control is to receive the control signal of the regulator or the computer and to change the flow of the medium to be adjusted so as to maintain the adjusted parameter within the required range so as to automate the production process. If the automatic adjustment system compared with the manual adjustment process, the detection unit is the human eye, the control unit is to adjust the human brain, then the execution unit - diaphragm pump is the human hand and foot. To achieve a certain parameters of the process such as temperature, pressure, flow, level and other regulatory control, are inseparable from the diaphragm pump. The choice of diaphragm pump is a very meticulous work, not only have a solid professional theoretical knowledge, but also have rich practical experience. Good choice not only conducive to adjusting the control loop PID parameter setting, so that the parameters are to be tuned to better control effect, but also greatly increase the service life of the diaphragm pump.
In the specific choice, from the following aspects: (1) The shape of the spool is mainly based on the selected flow characteristics and unbalanced forces and other factors to consider. (2) Wear resistance When the fluid medium is a suspension containing high concentration of abrasive particles, the valve core, the valve seat joint surface will be severely rubbed each time it is closed. Therefore, the flow of the valve should be smooth, the valve's internal material to be hard. (3) Corrosion resistance Due to the corrosive medium, try to choose a simple structure of the valve in the case of regulatory function. (4) Medium temperature, pressure When the medium temperature, high pressure and changes, should use the valve core and valve seat material by temperature, pressure changes in small valves. (5) to prevent flash and cavitation flash and cavitation only produce liquid medium. In the actual production process, flash and cavitation not only affect the calculation of flow coefficient, but also the formation of vibration and noise, so that the valve life is shorter, so the valve should be selected to prevent flash and cavitation.