Editing Valve (section)

===Body===
The valve's body is the outer casing of most or all of the valve that contains the internal parts or ''trim''. The bonnet is the part of the [[casing (borehole)|encasing]] through which the [[stem (bicycle part)|stem]] (see below) passes and that forms a guide and seal for the stem. The bonnet typically screws into or is bolted to the valve body.

Valve bodies are usually [[metal]]lic or [[plastic]]. [[Brass]], [[bronze]], [[gunmetal]], [[cast iron]], [[steel]], [[alloy steel]]s and [[stainless steel]]s are very common.<ref>{{cite web|url=https://www.actuation.co.uk/valve-body-types|title=Types of valve bodies and their specifications - Actuation Valves|website=www.actuation.co.uk}}</ref> Seawater applications, like desalination plants, often use duplex valves, as well as super duplex valves, due to their corrosion resistant properties, particularly against warm seawater. [[Alloy 20]] valves are typically used in sulphuric acid plants, whilst [[monel]] valves are used in [[hydrofluoric acid]] (HF Acid) plants. [[Hastelloy]] valves are often used in high temperature applications, such as nuclear plants, whilst [[Hydrogen valve|inconel]] valves are often used in hydrogen applications. Plastic bodies are used for relatively low pressures and temperatures. [[PVC]], [[Polypropylene|PP]], [[PVDF]] and [[Fiberglass|glass-reinforced nylon]] are common plastics used for valve bodies.{{Citation needed|date=November 2009}}