Pressure seal bonnet

Pressure seal bonnet on a wedge gate valve

PRESSURE SEAL BONNET

Our 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 basic operation of this kind of valve, where the seal is achieved from the pressure exerted by the fluid flowing trough the valve, is as follows:

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

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 issues. Gaskets are carefully designed to produce a tight seal regardless of the line conditions, that can be easily dismantled for maintenance operations.

Forces making the seal in a pressure seal bonnet

Forces making the seal in a pressure seal bonnet