Valve has important role in steam boiler. Valve is one of required equipments in steam boiler to control flow of water or steam. Control velocity, debit, volume of fluids, and to make flow start or stop, are some of roles of valve.
Valve can be classified by internal configuration. Based on internal configuration valve can be classified as globe valve, ball valve, check valve, non return valve, gate valve, and butterfly valve.
Gate valve is valve that is used to make flow fully stop or fully open, there is minimum restriction in this type and usually used for straight line flow. Globe valve is valve which is used to regulate flow, and the fluids will has more resistance if flow through globe valve than gate valve.
Check valve is valve which is used for flow one way direction or non return direction. Non return valve is used to eliminate steam flow back into a steam boiler if the pressure of steam line piping is under the pressure of header in steam boiler; this type is automatic stop check valve.
Butterfly valve is valve which is used for regulate and isolate flow, it allow for quick stop flow. Ball valve has similar function with butterfly valve, the differences is ball valve use spherical disc to regulate flow.
Valve can be also classified by function in steam boiler, Based on its function valve can be categorized as vent valve, safety valve, control valve, safety shut off valve, and so on. Vent valve is used for release air or steam when steam boiler is being filled with water; it is usually located on the highest level. Safety valve is used for protect steam boiler if operating pressure exceed maximum allowable working pressure, the valve will automatically pop up to release excess pressure. Control valve is automatic control to regulate how many percent debit flow of fluid will be allowed. Safety shut off valve is used to close and stop line flow of fluid.