Parker Hannifin Corporation Fluid Control Solutions Europe General Catalogue FCSE/0112/UK V2.2 07/2022 505 Notes: 1) Should the value ΔP not be specified, use the following, which is based on experience: • For liquids only in the case of free discharge ΔP = 90% of the input pressure (P1). • For gases never use a ΔP of more than 50% of the absolute inlet pressure, since the excessive pressure drop may cause an irregular flow rate. In most cases, ΔP can be considered as 10% of the input pressure. 2) Specific volume value (Vs) for dry saturated steam, see the table in diagram 3. c) Solenoid valves for steam: If ΔP ≤ 1/2 P1 use the following formulae: Flow rate: Qv = 31,7 • Kv •√ ΔP Vs where: Qv = Kg/h ΔP = bar Vs = m3/Kg Flow coefficient: Kv = Qv • √ Vs 31,7 ΔP Pressure drop: ΔP = Vs • Qv2 (31,7 x Kv)2 If ΔP > 1/2 P1 use the following formula: Qv = 22,4 • Kv√ P1 Vs b) Solenoid valves for gases: If ΔP ≤ 1/2 P1 use the following formulae: Flow rate: Qn = 514 • Kv •√ ΔP • P2 γ n • (273 + t) where: Qn = Nm3/h P1 = bar P2 = bar Flow coefficient: Kv = Qn • √(273+t) • γ n 514 ΔP • P2 Pressure drop: ΔP = (273 + t) • γ n • Qn2 P2 (514 • Kv)2 If ΔP > 1/2 P1 use the following formula: Qn = 757 • Kv •√ ΔP • P2 (273 + t) • γ n t = °C γ n = Kg/dm3 TECHNICAL INFORMATION
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