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Double Check Valve
A double check valve or double check assembly (DCA) is a backflow prevention device designed to protect water supplies from contamination. 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. It consists of two check valves assembled in series. This employs two operating principles: firstly one check valve will still act, even if the other is jammed wide open. Secondly the closure of one valve reduces the pressure differential across the other, allowing a more reliable seal and avoiding even minor leakage. Small valves may be so compact as to be barely noticeable particularly when they are integrated into the bodies of existing taps (faucets). Larger check valves may be installed with ball valves at the ends, for isolation and testing. Often, test cocks (very small ball valves) are in place to attach test equipment for evaluating whether t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrostatic Loop
A hydrostatic loop, though not often used in plumbing practice, is an arrangement of pipes formed into a vertical loop to prevent backflow of water within the plumbing potable water system. Since a siphon has a maximum height that it can work (about 33 feet), a hydrostatic loop is built higher than 33 feet. There are several ways to prevent siphonage and an undesirable backflow of the water in a plumbing system. * Vented loops References See also * backflow prevention * Pressure vacuum breaker * Double check valve * Chemigation valve * Reduced pressure zone device * Atmospheric vacuum breaker An Atmospheric Vacuum Breaker (AVB) is a backflow prevention device used in plumbing to prevent backflow of non-potable liquids into the drinking water system. It is usually constructed of brass and resembles a 90-degree elbow with a hood on its ... Plumbing valves {{watersupply-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plumbing Valves
Plumbing is any system that conveys fluids for a wide range of applications. Plumbing uses pipes, valves, plumbing fixtures, tanks, and other apparatuses to convey fluids. Heating and cooling (HVAC), waste removal, and potable water delivery are among the most common uses for plumbing, but it is not limited to these applications. The word derives from the Latin for lead, ''plumbum'', as the first effective pipes used in the Roman era were lead pipes. In the developed world, plumbing infrastructure is critical to public health and sanitation. Boilermakers and pipefitters are not plumbers although they work with piping as part of their trade and their work can include some plumbing. History Plumbing originated during ancient civilizations, as they developed public baths and needed to provide potable water and wastewater removal for larger numbers of people. The Mesopotamians introduced the world to clay sewer pipes around 4000 BCE, with the earliest examples found in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Brake (road Vehicle)
An air brake or, more formally, a compressed-air-brake system, is a type of friction brake for vehicles in which compressed air pressing on a piston is used to apply the pressure to the brake pad or brake shoe needed to stop the vehicle. Air brakes are used in large heavy vehicles, particularly those having multiple trailers which must be linked into the brake system, such as trucks, buses, trailers, and semi-trailers, in addition to their use in railroad trains. George Westinghouse first developed air brakes for use in railway service. He patented a safer air brake on March 5, 1872. Westinghouse made numerous alterations to improve his air pressured brake invention, which led to various forms of the automatic brake. In the early 20th century, after its advantages were proven in railway use, it was adopted by manufacturers of trucks and heavy road vehicles. Design and function Air brakes are typically used on heavy trucks and buses. Typical operating pressure is approximatel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reduced Pressure Zone Device
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, reduced pressure zone assemblies (RPZA), or reduced pressure principle assembly (RPPA). * ASSE Standard 1013 - Reduced Pressure Backflow Assembly * ASSE Standard 1015 - Double Check Valve Assembly * ASSE Standard 1020 - Pressure Vacuum Breaker * ASSE Standard 1047 - Reduced Pressure Detector Assembly * ASSE Standard 1047 - Reduced Pressure Detector Assembly Type II * ASSE Standard 1048 - Double Check Detector Assembly * ASSE Standard 1048 - Double Check Detector Assembly Type II * ASSE Standard 1056 - Spill Resistant Vacuum Breaker Backflow preventers are categorized into three groupings: Assembly, Device or Method. With the exception of elimination, these are the only ways one can control backflow from taking place. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Vacuum Breaker
An Atmospheric Vacuum Breaker (AVB) is a backflow prevention device used in plumbing to prevent backflow of non-potable liquids into the drinking water system. It is usually constructed of brass and resembles a 90-degree elbow with a hood on its top to allow air to enter the water system if a siphon attempts to form. Inside this elbow is a poppet valve that is held "up" by the water pressure found in the system, closing the air entrance to the device. If the pressure in the "upstream side" is reduced to atmospheric pressure or below, the poppet valve drops and allows air to enter the system, breaking the siphon. These devices, since they work on atmospheric principles, cannot be installed in an enclosure containing air contaminants. Those contaminants could be drawn into the device, thus fouling the pipes. AVBs must be installed a minimum of 6 inches above the highest usage point in the system (i.e. sprinkler, drip emitter, etc.) Underground installation of AVBs is ''entirely ine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reduced Pressure Principle BFP
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, reduced pressure zone assemblies (RPZA), or reduced pressure principle assembly (RPPA). * ASSE Standard 1013 - Reduced Pressure Backflow Assembly * ASSE Standard 1015 - Double Check Valve Assembly * ASSE Standard 1020 - Pressure Vacuum Breaker * ASSE Standard 1047 - Reduced Pressure Detector Assembly * ASSE Standard 1047 - Reduced Pressure Detector Assembly Type II * ASSE Standard 1048 - Double Check Detector Assembly * ASSE Standard 1048 - Double Check Detector Assembly Type II * ASSE Standard 1056 - Spill Resistant Vacuum Breaker Backflow preventers are categorized into three groupings: Assembly, Device or Method. With the exception of elimination, these are the only ways one can control backflow from taking place. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemigation Valve
Sometimes called a check valve or a backflow preventer, a chemigation valve is an apparatus designed to protect water supplies from agricultural chemicals used during chemigation, the application of chemicals such as fertilizers and pesticides through irrigation water. Most chemigation valves consist of a spring-loaded check valve, a low pressure drain, an air and vacuum relief valve, and an injection port for introducing the chemicals downstream of the check valve. Many chemigation valves also have a 4-inch inspection port so that a person can reach inside and feel if the check valve is still functional. Some governments require the use of two chemigation valves installed in series if hazardous chemicals are to be injected. The following policies require or encourage the installation of these valves: Texas State law Chapter 344.73 in Subchapter D - 1.(b) : "An irrigation system which adds any chemical is considered to be a 'high health hazard'. Such an irrigation system mus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pressure Vacuum Breaker
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 are downstream. Pressure vacuum breakers must be protected from freezing when installed outdoors. PVBs usually have test cocks, to which specially-calibrated gauges are attached, in order to ensure that they are functioning properly. Backflow prevention devices such as PVBs are regulated by the Uniform Plumbing Code, but may also be required by government regulations. See also * Air gap * Atmospheric vacuum breaker * Chemigation valve * Double check valve * Hydrostatic loop * Reduced Pressure Principle BFP A reduced pressure zone device (RPZD, RPZ, or RPZ valve) is a type of backflow prevention device used to protect water supplies from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Gap (plumbing)
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. Air gaps of appropriate design are required for water safety by legislation in many countries. A related term in computer security is ''network air gap''. A simple example is the space between a wall mounted faucet and the sink rim (this space is the air gap). Water can easily flow from the faucet into the sink, but there is no way that water can flow from the sink into the faucet without modifying the system. This arrangement will prevent any contaminants in the sink from flowing into the potable water system by siphonage and is the least expensive form of backflow prevention. A common use of the term "air gap" in home plumbing refers to a fixture that provides back-flow prevention for an installed dishwasher. This "air gap" is seen above the sink as a small cylindrical fixture mounted parallel with the faucet. In the base cabinet under ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reduced Pressure Zone Device
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, reduced pressure zone assemblies (RPZA), or reduced pressure principle assembly (RPPA). * ASSE Standard 1013 - Reduced Pressure Backflow Assembly * ASSE Standard 1015 - Double Check Valve Assembly * ASSE Standard 1020 - Pressure Vacuum Breaker * ASSE Standard 1047 - Reduced Pressure Detector Assembly * ASSE Standard 1047 - Reduced Pressure Detector Assembly Type II * ASSE Standard 1048 - Double Check Detector Assembly * ASSE Standard 1048 - Double Check Detector Assembly Type II * ASSE Standard 1056 - Spill Resistant Vacuum Breaker Backflow preventers are categorized into three groupings: Assembly, Device or Method. With the exception of elimination, these are the only ways one can control backflow from taking place. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
