GATE Valves

Another type of bonnet construction in a gate valve is pressure-sealed bonnet. This construction is adopted for valves for high pressure service, typically in excess of 2250psi (15MPa). The unique feature of the pressure seal bonnet is that the bonnet ends in a downward-facing cup that fits inside the body of the valve.

As the internal pressure in the valve increase, the side of the cup are forced outward. Improving the body-bonnet seal. Other construction where the seal is provided by external clamping pressure tend to create leaks in the body-bonnet joint.