5 dresser valve division masoneilan liquid flow equations cv valve flow coefficient n numerical constants based on units used see table 1 fp piping geometry factor reducer correction ff liquid critical pressure factor 0 96 0 28 pv pc fl liquid pressure recovery factor for a valve flp combined pressure recovery and piping geometry factor for a valve with attached fittings. Therefore δq q 8 8 1 and the percentage change is 100 δq q 100 at x 0 5.
Valve size gate globe stop check swing check tilting disc check and lift check full port cv t pattern cv y pattern cv full port cv min.
Globe valve cv curve. Ball valve flow coefficients c v flow coefficients c v for typical ball valves reduced and full bore leakage classification of control valves seat leakage classification through control valves. Flow coefficients cv values the flow coefficiency cv of a valve is the rate of gallons per minute of water at 60 f through a fully opened valve at a pressure drop of 1 psi across the valve. Flow coefficient c v it is the full capacity flow rate through the valve in us gallons min.
Size 150 300 600 900 1500 2500 2 42 42 42 45 38 25 2 5 67 67 67 3 100 100 100 90 95 65 4 185 185 185 170 170 1005 6 440 440 440 400 395 265. The use of this flow coefficient c v calculator leads to a standard calculation to compare valve capacities. It allows you to calculate the flow or c v flow coefficient to make the relationship visible between the pressure drop the difference in pressure between two points in a network transporting a liquid or gas and the flow rate.
The full closure curve of a ball valve is then the above graph multiplied by the valve s flow coefficient or factor. Cv kv fraction vs angle closure curve chart. Flow velocity regular port cv flow velocity for fully open 1 for fully open 1 ft sec water 60ºf ft sec water 60ºf 1 1 2 93 16 31 55 9 89 32 7 20 2 170 30 57 101 9 43 60 6 87 2 1 2 273 48 92 161 9 08.
Of water at 60 f with a pressure drop of 1 psi. Gallons per minute that passes through the valve at a pressure drop of 1 psi at 68 f. This is our valve c v calculator.
This graph shows the cv or kv valve fraction vs opening and closing angle of a full bore ball valve. C v flow calculator. Cv is in imperial units.
The globe plug can be at any position between fully opened and fully closed to control flow through the valve. For an equal percentage valve the percentage change in flow rate when the valve opens from 50 to 60 δx 0 1 must be equal to the percentage change in flow rate when the valve opens from 60 to 70 the same δx of 0 1. Cv vs angle closure curve values table.
Flow coefficient k v volumetric flow rate of water at a. Control valves control valve terminology bodies trim flow characteristics cv and kv sizing noise actuators and positioners. Cv is the volume of water in u s.
In metric units the same coefficient often called the flow factor is kv and corresponds to the flow rate of water in. Flow coefficient information scope the values given below are applicable to floating ball valve tru nnion mounted ball valve when the ball valve is in full open condition. Globe valves consist of a movable disk type element and a stationary ring seat in a generally spherical body.
The valve stem moves a globe plug relative to the valve seat.