The selection of diaphragm pump caliber and determining the main circulation capacity of the main valve is CV. In the design and selection of various projects, CV calculations must be performed on the diaphragm pump, and the diaphragm pump design instructions must be provided. The CV of the diaphragm pump is calculated to the diameter of the valve. Generally, the following steps are required:

1) Calculate the determination of traffic. The existing production capacity, equipment load and medium status, determine the QMAX and Qmin.

2) Determination of the pressure difference between the valve. Select S (resistance coefficient) according to the selected valve flow characteristics and system characteristics, and then determine the calculation pressure difference.

3) Calculate CV. Select the appropriate calculation formula and chart according to the adjusted media, and find CMAX and CMIN.

4) Select CV. According to CMAX, select the> CMAX in the selected product standard series and the closest to its first C.

5) Open calculation of diaphragm pump. Generally, the opening degree of the maximum calculation of the flow is 90%, and the opening degree of the minimum calculation of the flow is 10%.

6) The actual compatibility of the diaphragm pump can be calculated. The actual adjustment ratio is generally required.

7) Determination of valve seat diameter and nominal diameter. After the verification is appropriate, it is determined according to C.