Types

• There are two types of gate valve, resilient-seated and metal-seated. Resilient seated gate valves require sufficient force to compress the gate rubber against the valve body, while in metal-seated gate valves the gate slides into guides in the valve body.
  
  

Torque

• The maximum allowable torque for a 3-inch gate valve, whether resilient- or metal-seated, is 165 foot-pounds. The torque required to seal resilient-seated gate valves, compared to metal-seated gate valves, increases as the valve size increases.
  
  

Considerations

• Gate valves should only be fully opened or fully closed. They are unsuitable for throttling or modulating applications because the velocity of the liquid flowing past the gate causes vibration and damage.