A bulk of the boiler valves is made up of GGC category, a trade acronym for gate, globe and check valves. Additionally, there are SVs and CVs.
21.3.2 Valve Terminology
The terms used in valve construction are first defined. A manually operated LP gate valve with flanged ends and bolted bonnet having inside screw and rising stem is shown in Figure 21.1 where the various parts are labelled.