INTRODUCTION

  • A gate valve is a linear motion valve used to start or stop fluid flow but, it does not regulate or throttle flow.
  • Gate valves are obtainable in various sizes ranging from ½” to 30” and also various pressure ratings (150# up to API 10 000).
  • Gate valves also come in different end connection such as Flanged end, Socket Weld end, Butt Weld end, and Hub end.
  • Gate Valves are designed to operate fully open or fully closed. There is very little pressure loss through a gate valve. In the fully closed position, gate valves provide a positive seal under pressure.
  • Classification of gate valves is usually made by the type disc used:
    • Solid wedge
    • Flexible wedge
    • Split wedge
    • Parallel disk

OPERATION

  • When the valve is fully closed, a disk-to-seal ring contact surface exists for 360°, and good sealing is provided.
  • On opening the gate valve, the flow path is enlarged in a highly nonlinear manner with respect to percent of opening.
  • This means that flow rate does not change evenly with stem travel.

APPLICATION

  • A gate valve can be used for a wide variety of fluids and provides a tight seal when closed.
  • Gate valves are preferred to be use in applications involving slurries.
  • They are also used in applications that involve viscous liquids such as heavy oils, light grease, varnish, molasses, honey, cream and other non-flammable viscous liquids.
  • Gate valves play an important role in virtually every chemical plant, refinery pipeline industry, salt working pipelines and power industry.