wedge gate valve

Babcock Valve’s pressure seal bonnet on a double gate valve

PRESSURE SEAL BONNET

Our double disc gate valves can adopt pressure seal bonnets to allow high pressure service, typically in excess of 15 Mpa (2250 psi). The main feature about the pressure seal bonnet is that the body – bonnet joints seals improves as the internal pressure in the valve increases, compared to other constructions where the increase in internal pressure tends to create leaks in the body-bonnet joint.

The seal is is achieved from the pressure exerted by the fluid flowing trough the valve as follows:

Internal pressure forces the bonnet upwards against the gasket, creating forces in the contact areas between the gasket and the bonnet.

Leaks most commonly arise at the contact surface between the gasket and the body. The area where the body is in contact with the joint is covered by stainless steel, improving surface’s quality and avoiding corrosion problems.

pressure seal bonnet of a double disc gate valve

Double disc gate valve’s pressure seal bonnet.

NOTES

  • The valve weight is for Butt Welding ends.
  • Dimensions in mm. and weights in kg.
  • Dimensions not shown for classes 2500 and 4500 will be given acc. to customer requirements