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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 ...
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 ...
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.
Example of symbol for a stop valve. A stopcock is a form of valve used to control the flow of a liquid or gas. The term is not precise and is applied to many different types of valve. The only consistent attribute is that the valve is designed to completely stop the flow when closed fully.
Control valve. A control valve is a valve used to control fluid flow by varying the size of the flow passage as directed by a signal from a controller. [ 1] This enables the direct control of flow rate and the consequential control of process quantities such as pressure, temperature, and liquid level. In automatic control terminology, a control ...
D000067716. Point-of-care testing ( POCT ), also called near-patient testing or bedside testing, is defined as medical diagnostic testing at or near the point of care —that is, at the time and place of patient care. [ 1][ 2] This contrasts with the historical pattern in which testing was wholly or mostly confined to the medical laboratory ...
Engineering drawing abbreviations and symbols are used to communicate and detail the characteristics of an engineering drawing. This list includes abbreviations common to the vocabulary of people who work with engineering drawings in the manufacture and inspection of parts and assemblies. Technical standards exist to provide glossaries of ...
A separate actuator on the piping releases pressure in the line if it crosses a threshold. This releases the pressure on the back of the seal, causing the valve to open. The essential parts of a PORV are a pilot valve (or control pilot), a main valve, a pilot tube, the dome, a disc or piston, and a seat. The volume above the piston is called ...