Self control valve constant flow valve pressure setting. Sg specific gravity of fluid reference against water at 60 f now we discuss about how we get the conversion factor of 1 156 in the formula cv 1 156kv.
1 kvt 2 1 kv1 2 1 kv2 2 1 where.
Control valve cv values. δp differential pressure. Root of δp sg q flow in us gpm. The flow coefficient for a control valve which in full open position passes 25 gallons per minute of water with a one pound per square inch pressure drop can be calculated as.
Gallons per minute of water at 60 f that will flow through a control valve at a specified opening when a pressure differential of 1psi is applied across the valve. For a specific control valve flow coefficient cv kv is determined experimentally by control valve manufacturers and you can found it in manufacturers technical specifications. The flow rate for a liquid q cv sq.
Kv1 kv valve 1. Kv2 kv valve 2. What is the flow through the valve.
M3 h for a pressure drop of 1 psi 1 bar across a flow passage flow coefficient. Kvt resulting kv. It applies to the factor of the head drop δh or pressure drop δp over a valve with the flow rate q.
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. The definition of cv is the number of gpm gallons per minute that will pass through the control valve with a pressure drop of 1psi. It is water at 50 c.
Cv 1 156 kv. A control valve has a cv of 5. 0 05 1 0 mpa renge for preset flow rate and working differential pressure.
Calculation example of the flow through a valve of coefficient cv. A valve cv can be described as the number of gallons per minute gpm at 60of 15 5oc that will pass through a valve with an associated pressure drop of 1 psi. Control valve cv refers to the flow coefficient of the valve.
The density of water at 15 c is 999 13 kg m 3. The equivalent flow coefficient kv or cv for two control valves installed in series can be calculated as. Control valves in series.
Cv value swing check valve 14 14 24 81 140 250 280 510 750 1 100 1 900. The instrumentation on the line show that the pressure drop through the valve is 0 1 bar. Kv 0 864 cv.
Example flow coefficient liquid. The valve flow coefficient cv or its metric equivalent kv has been adopted universally as a comparative value for measuring the capacity of control valves. They express coefficient cv kv as the flow rate of water in g p m.
Cv 25 gpm 1 1 psi 1 2. The valve flow coefficient cv is the number of u s. Control valve cv calculation 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.
Cv flow coefficient of control valve. In simple terms a fully open control valve with a cv of 14 usgpm psi passes 14 usgpm of fluid with 1 psi pressure drop.