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A Block and bleed manifold is a hydraulic manifold that combines one or more block/isolate valves, usually ball valves, and one or more bleed/vent valves, usually ball or needle valves, into one component for interface with other components (pressure measurement transmitters, gauges, switches, etc.) of a hydraulic system. The purpose of the ...
This may comprise a ‘double block’ consisting of two valves in series. Still more effective is a ‘double block and bleed’ comprising two isolation valves in series plus a bleed valve between them. The bleed valve enables the integrity of the valve on the hazardous side to be monitored. [5]
PWB – production wing block (XT [clarification needed]) PWHT – post-weld heat treat; PWRI – produced water reinjection; PWV – production wing valve (also known as a flow wing valve on a christmas tree [citation needed])
Diaphragm valves (or membrane valves) consists of a valve body with two or more ports, a flexible diaphragm, and a "weir or saddle" or seat upon which the diaphragm closes the valve. The valve body may be constructed from plastic , metal or other materials depending on the intended use.
The labels used on pipes must be positioned visibly in the vicinity of the most hazardous points, such as valves and joints; at both sides of bulkheads and floor penetrations; and at reasonable intervals. The regulations do not specify a specific marking system, but BS EN ISO 1710 Graphical symbols — Safety colours and safety signs is often used.
Brass-bodied float valve. An automatic bleeding valve or air release valve (ARV) is a plumbing valve used to automatically release trapped air from a heating system. Air, or other gas, may collect within plumbing. For water delivery systems to taps and basins, particularly with good main supply pressure, this air is usually flushed through with ...
A check valve, non-return valve, reflux valve, retention valve, foot valve, or one-way valve is a valve that normally allows fluid (liquid or gas) to flow through it in only one direction. [1] Check valves are two-port valves, meaning they have two openings in the body, one for fluid to enter and the other for fluid to leave. There are various ...
A double check valve or double check assembly (DCA) is a backflow prevention device designed to protect water supplies from contamination. [1] It is different from the two-way check valves (sometimes erroneously referred to as double check valves) used in air brake systems on heavy trucks which select from the highest pressure source.