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Valve selection guide PERIPHERAL DEVICES TIPS OF THE TRADE VALVE SELECTION GUIDE ? CONTENTS ? SIZING SPARTAN WATER VALVES Calculating Cv Calculating Di ?erential Pressure Calculating the Flow Through a Valve Taking Adequate Pressure Drop Across the Contro

PERIPHERAL DEVICES TIPS OF THE TRADE VALVE SELECTION GUIDE ? CONTENTS ? SIZING SPARTAN WATER VALVES Calculating Cv Calculating Di ?erential Pressure Calculating the Flow Through a Valve Taking Adequate Pressure Drop Across the Control Valve Exceptions to a High Di ?erential Pressure Equal Percentage Plugs or Logarithmic Plugs Spartan Proportioning Plug Valves Turndown Ratio Double-seated Valves SELECTING SPARTAN VALVE TOPS Sizing Pneumatic Tops Normally-open Valves Normally-closed Valves SIZING SPARTAN STEAM VALVES FIGURES Steam is a Unique Medium to Control for it Follows Unusual Laws Heat Emission vs Flow Characteristics of Typical Hot Water Heating Coil To Calculate the Cv of a Valve When Using Steam Supersaturated Steam Percent of Full Flow Steam Valve Sizing Estimating Control Contracts Two-way Valve Piping Valve Piping N O and N C Valve Bodies TYPICAL BYPASS PIPING Three-way Valve Piping Three-way Valve Piping Constant Flow Systems Common Piping Errors TYPICAL THREE-WAY PIPING Three-way Mixing Valves Three-way Diverting Valves Constant Flow Systems Spartan Four Port Valves Four-port Valves Typical Single- and Double-seated Valves Typical Three-way Mixing and Diverting Valves Double Seated Valves - Reverse Direct Action ASHRAE Valve Characteristics Graph View from Side of a Typical Fan Coil Unit CONTROL EQUIPMENT AND PERIPHERAL DEVICES FOR EFFICIENT ENERGY MANAGEMENT Spartan Peripheral Devices ? telephone - ? fax - ? E-mail info spartan-pd com ? Website www spartan-pd com SP-V S G - - CPERIPHERAL DEVICES TIPS OF THE TRADE CONTROL VALVE SELECTION GUIDE Valve selection is an important part of the design of a control system and the proper choice will enhance performance while reducing costs Often valves are selected too large impairing performance requiring stronger operators and needlessly escalating costs This section describes how to properly size Spartan valves for best performance and for best value SIZING SPARTAN WATER VALVES Obviously the maximum operating pressure of the valve should be ?rst considered or class valves may be needed depending upon the maximum pressure the valve will encounter When choosing this pressure class allow for the addition of the circulating pump pressure if this pressure will or could be added to the static pressure CALCULATING THE FLOW THROUGH A VALVE To ?nd the amount of water able to be passed by a valve F Cv x ??PD example Remember that psi is equal to a head of ' and that a The ow through a valve with a Cv of and a pressure building ' high will have a water pressure at the bottom drop of psi would be x ?? U S GPM greater than psig This can be used as a guide but it is always best to check with the consulting engineer for the project TAKING ADEQUATE PRESSURE DROP ACROSS THE CALCULATING Cv CONTROL VALVE The Cv of a Spartan valve is de ?ned as the amount of water at F C which will ow through it in the wide open position with a di ?erential pressure of psi A valve with a Cv of will pass gallons per minute with a psi