INTRODUCTION

  • A swing check valve is a type of valve which the valve disc attached to the hinge and swing onto the seat or off the seat to prevent the back flow of the fluid and only permitting the fluid to flow in one direction.
  • These valves are fully closed when the flow reaches zero and prevent back flow.
  • Swing check valve available in 2” to 24” of range size.
  • The pressure classes for swing check valves are 150# to API 10 000.

OPERATION

  • The swing check valve functions by allowing flow forces to move the disc from the closed position to the fully open position in a sweeping arc motion against the hinge stop inside of the valve body.
  • Due to the weight and center of gravity location of the disc and swing arm assembly, the valve will return to the closed position when the flow become interrupted or reversed.
  • External counterweights mounted on the hinge pin are sometimes used to increase or decrease the reaction time and speed of the disc returning to the closed position.
  • Swing check valves have no requirement for operators, and so the valve is operated automatically by flow reversal.
  • The flow direction of the fluid is indicated by the arrow on the swing check valve body.

APPLICATION

  • A swing check valve is recommended for use in systems consisting of gate valves because of the low pressure drop across the valve.
  • Swing check valve also recommended for systems having low velocity flow and should not be used on systems with pulsating flow when the continuous flapping or pounding would damage the seat.