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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 ...
Air pilot control: converting from air to oil results in locking of the cylinder. Shifting the four-way valve to either extreme position applies the air pilot through the shuttle valve, holding the two air-operated valves open and applying oil under air pressure to the corresponding side of the cylinder. Positioning a manual valve to neutral ...
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.
A piping and instrumentation diagram (P&ID) is defined as follows: A diagram which shows the interconnection of process equipment and the instrumentation used to control the process. In the process industry, a standard set of symbols is used to prepare drawings of processes. The instrument symbols used in these drawings are generally based on ...
In a feature control frame ( FCF ), the ⌀ symbol tells you that the tolerance zone for the geometric tolerance is cylindrical. Abbreviations for "diameter" include ⌀, DIA, and D. D. diameter; delta. Abbreviations for "diameter" include ⌀, DIA, and D. For delta usage, see for example "delta notes". DIA[ 2] diameter.
An air gap, as related to the plumbing trade, is the unobstructed vertical space between the water outlet and the flood level of a fixture. [ 1] Air gaps of appropriate design are legally required by water health and safety regulations in many countries. An air gap is the simplest form of a backflow prevention device .
An air-operated valve, also known as a pneumatic valve, is a type of power-operated pipe valve that uses air pressure to perform a function similar to a solenoid. As air pressure is increased, the compressed air starts to push against the piston or diaphragm walls which causes the valve to actuate. Whether the valve opens or closes depends on ...
A pressure vacuum breaker (PVB) is a type of backflow prevention device, used to keep non- potable (or contaminated) water from entering the water supply. A PVB is similar to an atmospheric vacuum breaker (AVB), except that the PVB contains a spring-loaded poppet. This makes it acceptable for applications that are high hazard or where valves ...