Do you know a Table or Figure where could I calculate the Cv of a standard gate valve vs open or degrees of opening?My valve is a 10" 150 -lb wedge-shaped Carbon Steel and I don?t have documentation of the valve (20 years old)Gate valves are made for use as full open or full closed. They are for shut-off. They are not designed or recommended for throttling or control. Having made this point, I would now like to know and understand why you would want to (or need to) use a gate valve for throttling. Regardless of why you want to do this, and whether you should, basically there are three methods.1. The valve is lab tested at various openings and the Cv calculated from the test results. The best method. Call the manufacturer.2. Carefully measure the shape and area of the orifice opening at various positions and calculate Cv which requires knowing the loss coeficient for each geometric shape and it's position in the flow passage (which you probably will not know). This method will give you an idea but will contain errors.3. Find test data on a similar valve, and establish the percent of flow at various stroke positions, and apply these percentages to your valve. This will be of unknown accuracy.

MORE NEWS