Valves are created differently. Some don’t have bonnets while others do. Valve bonnets act like accessories where other internal valve components can attach.
There are designs that merge the bonnet with the body. In contrast, some designs have removable bonnets so it’s easy to expose other valve parts for cleaning or maintenance.
Screwed Bonnet Globe Valve
Often found in inexpensive globe valves, screws join the body and the bonnet.
Bolted Bonnet Globe Valve
This type uses bolts to attach the bonnet to the body. Considered the most common, the connection of the body to the bonnet is further enhanced by a gasket. In turn, seals it tightly.
Welded Bonnet Globe Valve
This type is welded instead of attached by screws or bolts, which makes the valve lighter. However, maintenance and repair could be challenging due to the nature of its connection.
Pressure Seal Bonnet Globe Valve
Applications requiring high temperatures and pressures often use this kind of bonnet. With Increased internal pressure, the gasket seal should be very durable as the body transfer the pressure to the gasket.