Diaphragm Pump aperture selection and determine the flow capacity of the valve that is mainly based on Cv. In a variety of engineering design and selection, to be carried out on the diaphragm Cv calculations and provide diaphragm design specification. Cv calculated from the diaphragm to the valve diameter is determined, subject to the following general steps:
1.calculation to determine the flow rate. Existing production capacity, equipment load and the media, decided to calculate the flow rate of Qmax and Qmin.
2.the differential pressure across the valve is determined. According to the selected valve flow characteristics and system characteristics of the selected S (drag coefficient), and then determine the calculation of the pressure.
3.Calculate Cv. Select the appropriate formulas and charts based on the adjusted medium, obtained Cmax and Cmin.
4.the choice of Cv. According to Cmax, in the selected standard product portfolio, select> Cmax and its closest level C.
5.the diaphragm opening checking. General requirements for the opening of ≯90% maximum calculated flow, the opening of the minimum calculated flow ≮10%.
6.diaphragm actual adjustable ratio of checking. General requirements for the actual adjustable ratio ≮10.
7.the seat diameter and nominal diameter determination. After proper verification, determined in accordance with C.