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A common source of unintentional backfeeding is an electrical generator (typically a portable generator) that is improperly connected to a building electrical system.A properly installed electrical generator incorporates the use of a transfer switch or generator interlock kit to ensure the incoming electrical service line is disconnected when the generator is providing power to the building.
Tilting-disc inconel check valve Check valve symbol on piping and instrumentation diagrams.The arrow shows the flow direction. Vertical lift check valve. 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.
Backflow occurs for one of two reasons, either back pressure or back siphonage. [1] Back pressure is the result of a higher pressure in the system than in its supply, i.e. the system pressure has been increased by some means. This may occur in unvented heating systems, where thermal expansion increases the pressure.
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.
A mathematical prediction of the flow of electric power in a network, based on a model of the actual or proposed system; necessary for planning of electrical grids. load following power plant A power plant that can economically be operated over a significant range of output, so as to meet varying electric power demand. load-loss factor
It is commonly used on lawn irrigation, fire sprinkler [2] and combi-boiler systems. [3] If the hazard is higher, even a relatively low hazard such as using antifreeze in the fire sprinkler system, then a more reliable check valve such as a reduced pressure zone device may be mandated.
The outlet valve allows flow from the chamber to the outlet line, but not in reverse. The motor repeatedly moves the piston into and out of the piston chamber, causing the volume of the chamber to repeatedly become smaller and larger. When the piston moves out, a vacuum is created. Low pressure in the chamber causes liquid to enter and fill the ...
A reduced pressure zone device (RPZD, RPZ, or RPZ valve) is a type of backflow prevention device used to protect water supplies from contamination. RPZDs may also be known as reduced pressure principle (RP), reduced pressure principle backflow prevention devices, [1] [2] reduced pressure zone assemblies (RPZA), [3] or reduced pressure principle ...