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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 simple one-way ball-type check valve, in its "open" state acts as a diode in its conducting state. A pressure-actuated valve combined with a one-way check valve acts as a (field-effect) transistor. Like a one-way check valve, a diode blocks current that flows the wrong way.
In the United States, the modern demarcation point is a device defined by FCC rules (47 C.F.R. Part 68) [ 1] to allow safe connection of third-party telephone customer-premises equipment and wiring to the Public Switched Telephone Network (PSTN). The modern demarcation point is the network interface device (NID) or intelligent network interface ...
The most common final control element in the process control industries is the control valve. The control valve manipulates a flowing fluid, such as gas, steam, water, or chemical compounds, to compensate for the load disturbance and keep the regulated process variable as close as possible to the desired set point. [ 1]
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 ...
Quality of service ( QoS) is the description or measurement of the overall performance of a service, such as a telephony or computer network, or a cloud computing service, particularly the performance seen by the users of the network. To quantitatively measure quality of service, several related aspects of the network service are often ...
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 ...
The QR code system was invented in 1994, at the Denso Wave automotive products company, in Japan. [5] [6] [7] The initial alternating-square design presented by the team of researchers, headed by Masahiro Hara, was influenced by the black counters and the white counters played on a Go board; [8] the pattern of position detection was found and determined by applying the least-used ratio (1:1:3 ...