GATE VALVES

 

 

Gate Valves work by inserting a rectangular gate or wedge into
the path of a flowing fluid. They are operated by a threaded stem which connects the actuator (generally a hand
wheel or motor) to the stem of the gate. If the valve has a rising stem its position can be seen just by
looking at the position of the stem.

 

This valve type is generally used to completely shut off fluid flow or, in the
fully open position, provide full flow in a pipeline. Thus it is used either in the fully closed or fully open
positions. A Gate Valve consists of a valve body, seat and disc, a spindle, gland, and a wheel
for operating the valve. The seat and the gate together perform the function of shutting off the flow of fluid.

 

 

Popular Manufacturers:


 

Wedge Gate Valve

  • Glenfield
  • Wolstenholmes
  • HNH
  • Triangle
  • Heaton
  • Blakeborough
  • Sella
  • Chapman
  • Crane
  • Velan

  • Ham Baker
  • Raimondi
  • Walworth
  • Hindle
  • Langley
  • LVF
  • Taylor
  • TT
  • Valvo Sider
  • Walworth

  • Fivi
  • Marchant
  • Kitz
  • Firsa
  • Weir Pacific
  • Holmes
  • Orion
  • Poyam
  • Donkin
  • Smith

  • MM
  • OMB Soleri
  • Malbranque
  • Guest & Chrimes
  • Sealand
  • Bonney
  • Douglas Chero
  • Fivalco
  • Shipham
  • Kitz 5
  • Fluval

 


 

Leak Rates for Valves

 

All valves are designed to meet a designated internal permissible leak rate standard (FCI/ANSI).  There are six (6) permissible leak rates or Classes numbered 1 through VI. The higher the leak rate number, the lower permissible internal leak rate.

 

  • Class I valve, will the highest internal leak rate and usually the lowest cost.
  • Class VI valve will have the lowest permissible internal leak rate therefore cost will increase.

 

Identifying the permissible internal leak rate for a valve has to be one of the top priorities when choosing the correct valve.  A valve with a high leak rate, will cause excessive wear. The valves with a high leak rate will internally pass more medium and result in premature valve failure.

 

There are six different seat leakage classifications as defined by ANSI FCI 70-2.

 

  • CLASS I: is also known as dust tight and can refer to metal or resilient seated valves.
  • CLASS IV: is also known as metal to metal. It is the kind of leakage rate you can expect from a valve with a metal shut-off disc and metal seat.
  • CLASS Vl: is known as a soft seat classification. Soft Seat Valves are those where the seat or shut-off disc or both are made from some kind of resilient material such as Teflon

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