Solenoid Valve Flow-rate Characteristics Series VXD ρ ΔP 2.3 Flow coefficient Cv factor The United States Standard ANSI/(NFPA)T3.21.3: 1990: Pneumatic fluid power.Flow rating test procedure and reporting method-For fixed orifice components Defines the flow coefficient, Cv factor by the following formula which is based on the test conducted by the test circuit analogous to ISO 6358. Q Cv = …………………………………………………(7) ΔP (P2 + Pa) 114.5 T1 ΔP : Pressure drop between the static pressure tapping ports [bar] P1 : Pressure of the upstream tapping port [bar gauge] P2 : Pressure of the downstream tapping port [bar gauge]: P2 = P1 . ΔP Q : Flow rate [dm3/s standard condition] Pa : Atmospheric pressure [bar absolute] T1 : Upstream absolute temperature [K] Test conditions are P1 + Pa = 6.5 ±0.2 bar absolute, T1 = 297 ±5 K, 0.07 bar . ΔP . 0.14 bar. This is the same concept as effective area A which ISO 6358 stipulates as being applicable only when the pressure drop is smaller than the upstream pressure and the compression of air does not become a problem. 3. Process fluid control equipment (1) Conformed standard IEC60534-2-3: 1997: Industrial-process control valves. Part 2: Flow capacity, Section Three-Test procedures JIS B 2005: 1995: How to test flow coefficient of a valve Equipment standards: JIS B 8471: Solenoid valve for water JIS B 8472: Solenoid valve for steam JIS B 8473: Solenoid valve for fuel oil (2) Definition of flow-rate characteristics Av factor: Value of the clean water flow rate represented by m3/s which runs through a valve (equipment for test) when the pressure differential is 1 Pa. It is calculated using the following formula. Av = Q ………………………………………………………………….(8) Av : Flow coefficient [m2] Q : Flow rate [m3/s] ΔP : Pressure differential [Pa] : Fluid density [kg/m3] (3) Formula for flow rate Described by the practical units. Also, the flow-rate characteristics are shown in Graph (2). In the case of liquid: ΔP Q = 1.9 x 106 Av ……………….………………………………………(9) G Q : Flow rate [L/min] Av : Flow coefficient [m2] ΔP : Pressure differential [MPa] G : Specific gravity [water = 1] In the case of saturated steam: Q = 8.3 x 106 Av ΔP (P2 + 0.1) ……………………………….…………(10) Q : Flow rate [kg/h] Av : Flow coefficient [m2] ΔP : Pressure differential [MPa] P1 : Upstream pressure [MPa]: ΔP = P1 . P2 P2 : Downstream pressure [MPa] ρ 143 VX2 VXK VXD VXZ VXS VXE VXP VXR VXH VXF2 VX3 VXA