ASCO脉冲阀流量计算.docVIP

Section 1: Overview ? This application enables the quick calculation of flow coefficient (Cv), pressure drop, or flow rate for 2 way general service valves. It should?be used?in?conjunction with ASCO publication Flow Rating of?ASCO Valves Cv Method, ?commonly known as? the?Red Hat ?Flow?Book. Parts of the following?were?taken ?from the ASCO publication: Almost?every?conceivable?fluid?is?being handled? today ?by automatic?or semi - automatic? electrically operated control valves. Applications of hydraulic and fluid mechanics ?are? so extensive that almost every engineer has found himself faced with the responsibility to select and size a control valve for one process or another. ASCO is? greatly interested?in?this subject because of the wide variety of?solenoid valves they manufacture,and has?developed aids to?properly select?a valve ?size?capable? of handling the required flow. This flow information has been published based on the Cv concept. Definition of Cv: The valve flow? coefficient, Cv, is?a capacity index, and is defined? as the number of U.S. gallons of?water per minute? that? will flow? through a valve with? a ?pressure drop of? one ?pound ?per? square inch. The Cv method is widely?used? is very adequately serving ?its purpose in solenoid?valve applications. The Fluid Control Institute has published standards for its use, such as FCI 62-1, ?58-2 and 61-1. Testing? of? solenoid? valves ?is? performed? within? the ?range of ?variables ?usually ?handled.?The? simplicity of determining the Cv rating for ?each design ?has proven? invaluable. The Cv of?a valve does? not? change. Once assigned to a valve, it can be used to solve flow problems involving any media; air, gas, liquid or vapor. Importance of Properly Sizing Valves: It?is very important?to properly size?a?valve. There?are ?undesirable?effects?in both? undersizing and?oversizing. ? Undersizing may result in: Inability to pass desired flow requirements. Flashing of liquids to vapors on outlet side