What is the flow coefficient cv and kv calculation of flow through a valve si units the flow through a valve can be calculated thanks to the pressure drop through the valve and a coefficient kv which represents the number of m3 h of water that goes through the valve at 15c and with a pressure drop of 1 bar. When sizing a control valve the most common approach is to calculate the flow coefficient cv which is a measure of the capacity of the valve body and trim.
It applies to the factor of the head drop δh or pressure drop δp over a valve with the flow rate q.
Control valve cv si units. When sizing calculating which size valve is needed for your application a control valve specialist needs to calculate the flow coefficient. A valve cv can be described as the number of gallons per minute gpm at 60 o f 15 5 o c that will pass through a valve with an associated pressure drop of 1 psi. The cv was designed for use with liquid flows it expresses the flow in gallons per minute of 60º f water with a pressure drop across the valve of 1 psi.
Kv 0 865 cv cv 1 156 kv equivalence between flow coefficients kv and cv valve cv si units. 3 2 flow coefficient cv imperial units the flow coefficient c is the standard flow rate which flows through a valve at a given opening referred to the following conditions. Control valve valve flow coefficient cv hence a valve with a specified opening giving cv 1 will pass 1us gallon of water at 60 degree fahrenheit per minute if 1psi pressure difference exists between the upstream and down stream points on each side of the valve.
The si derived unit for power is the watt. Liquid pressure recovery factor for a control valve without attached fittings dimensionless f lp. For measuring the valve capacity of control valves the coefficient cv or its metric equivalent kv is adopted.
Such as the renault number reynolds number flow rate flow the shock choking the involved joints in pipes fitting and the other by the values of these. In deciding the size of the control valve that port size we need to calculate the cv value of the process calculated cv by calculating cv has educated more than 50 years which is involved in. Control valve cv refers to the flow coefficient of the valve.
The valve coefficient cv in imperial unit the number of us gallon per minute of water at 60 f that will flow through a valve at specific. How do we get value 1 156 conversion factor in formula cv 1 156kv or cv 1 156 q sqrt g delta p. Calculating control valve cv.