Type of Gate Valves based on Bonnet:
1 Screwed bonnet:This is the simplest design available and it is used for inexpensive valves.
2 Bolted-bonnet:This is the most popular design and used in a large number of gate valves. This requires a gasket to seal the joint between the body and bonnet
3 Welded-Bonnet:This is a popular design where disassembly is not required. They are lighter in weight than their bolted-bonnet counterparts.
4 Pressure-Seal Bonnet:This type is used extensively for high-pressure high-temperature applications. The higher the body cavity pressure, the greater the force on the gasket in a pressure -seal valve.