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Selection guide 1 VD - E SELECTION GUIDE FOR CHECK VALVES CSELECTION GUIDE FOR CHECK VALVES TABLE OF CONTENTS VD - E INTRODUCTION SELECTION GUIDELINES SELECTION DIAGRAM LIQUIDS OR GAS AND STEAM FLOW LIQUIDS DAMPER CONTROLLED CLOSING OR UNCONTROLLED CLOSIN

VD - E SELECTION GUIDE FOR CHECK VALVES CSELECTION GUIDE FOR CHECK VALVES TABLE OF CONTENTS VD - E INTRODUCTION SELECTION GUIDELINES SELECTION DIAGRAM LIQUIDS OR GAS AND STEAM FLOW LIQUIDS DAMPER CONTROLLED CLOSING OR UNCONTROLLED CLOSING FREE-ACTING OR POSITIVE VALVE ACTION TYPE GZA NO FLOW CONTROL CAPABILITY OR FLOW CONTROL CAPABILITY TYPE RZN TYPE RZI TYPE GBZ COMBINED FUNCTION VALVE TYPE AZI COMBINED FUNCTION VALVE FULL BORE TYPE TYPE MFK GASES STEAM GRAVITY CLOSING OR ASSISTED CLOSING TYPE GMZ TYPE FCV WITH GRAVITY CLOSING TYPE FCV WITH ASSISTED CLOSING TYPE MAG WITH GRAVITY CLOSING TYPE MAG WITH ASSISTED CLOSING CONCLUSION PAGE PAGE PAGE PAGE PAGE PAGE PAGE PAGE PAGE PAGE PAGE PAGE PAGE PAGE PAGE PAGE PAGE PAGE PAGE PAGE PAGE PAGE PAGE Adams Armaturen GmbH Baukauer Str - D Herne Page CSELECTION GUIDE FOR CHECK VALVES VD - E INTRODUCTION The purpose of check valves or non-return valves is to allow uid ow in one preferred direction and to prevent back ow or ow in the opposite direction As pressure drops in a pipe and the uid momentum slows a check valve ideally begins to close As the ow direction reverses the check valve closes completely Based on this simple requirement it appears that a single check valve design would be su ?cient for use in any application In addition to this basic non-return function however there are other service requirements which must be met by a check valve design which can vary extensively with di ?erent applications The following examples will illustrate the di ?erent requirements imposed on check valves Consider a check valve used on a pump discharge where the pump supplies water to a long discharge line and also a check valve utilized on a steam extraction line from a turbine to a heater A pump discharge line check valve in a liquid requires a damping device so the valve can close after the pump trips to ensure controlled closure for maximum attenuation of pressure surge In a steam extraction line ow reversal can occur within seconds on loss of turbine pressure This requires a check valve with very fast closing capabilities low inertia of the valve disc and minimal inherent friction of all moving components so that the impact of delayed valve closure is reduced to a minimum The ADAMS range of check valves is probably the most comprehensive and sophisticated product line produced by any manufacturer Types available range from gravity closed fast acting tilting disc valves to ultra fast closing power assisted check valves for high pressure high temperature applications and ultimately to hydraulically damped combined function check valves for severe pump applications The majority of our check valve designs are furnished with the exclusive ADAMS inclined conical seal system This sealing system utilized to seat the disc properly in the closed position has been used in thousands of valves over the past years During our history we have continually improved and developed our seat technology to the forefront of valve technology