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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 drain-waste-vent system (or DWV) is the combination of pipes and plumbing fittings that captures sewage and greywater within a structure and routes it toward a water treatment system. It includes venting to the exterior environment to prevent a vacuum from forming and impeding fixtures such as sinks, showers, and toilets from draining freely ...
A backflow prevention device is used to protect potable water supplies from contamination or pollution due to backflow. In water distribution systems, water is normally maintained at a significant pressure to enable water to flow from the tap, shower, or other fixture. Water pressure may fail or be reduced when a water main bursts, pipes freeze ...
Valves are available in several types, based on design and purpose: Gate, plug, or ball valves – Isolation; Globe valve – Throttling; Needle valve – Throttling, usually with high precision but low flow; Butterfly or diaphragm valves – Isolation and throttling; Check valve – Preventing reverse flow (non-return)
Double check valve. 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 ...
A Tesla valve, called a valvular conduit by its inventor, is a fixed-geometry passive check valve. It allows a fluid to flow preferentially in one direction, without moving parts. The device is named after Nikola Tesla, who was awarded U.S. patent 1,329,559 in 1920 for its invention.
Rotary valve. A rotary valve in default (A) and engaged (B) positions. 1. input airflow; 2. output airflow; 3. valve tubing; 4. valve casing; 5. internal rotor; 6. valve ports, or "knuckles"; 7. rotor spindle. A rotary valve (also called rotary-motion valve) is a type of valve in which the rotation of a passage or passages in a transverse plug ...
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 valve is termed ...