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Backflow (plumbing)
Backflow is a term in plumbing for an unwanted flow of water in the reverse direction. It can be a serious health risk for the contamination of potable water supplies with foul water. In the most obvious case, a toilet flush cistern and its water supply must be isolated from the toilet bowl. For this reason, building codes mandate a series of measures and backflow prevention devices to prevent backflow. Causes Backflow occurs for one of two reasons, either ''back pressure'' or ''back siphonage''. ''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. ''Back siphonage'' is the result of supply pressure being ''lowered'' below that of the system. This may occur when a supply is interrupted or drained down. Risk of contamination The precise measures required to prevent backflow depend on the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Backflow Preventer In Front Of Residential Building
Backflow is a term in plumbing for an unwanted flow of water in the reverse direction. It can be a serious health risk for the contamination of potable water supplies with foul water. In the most obvious case, a toilet flush cistern and its water supply must be isolated from the toilet bowl. For this reason, building codes mandate a series of measures and backflow prevention devices to prevent backflow. Causes Backflow occurs for one of two reasons, either ''back pressure'' or ''back siphonage''. ''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. ''Back siphonage'' is the result of supply pressure being ''lowered'' below that of the system. This may occur when a supply is interrupted or drained down. Risk of contamination The precise measures required to prevent backflow depend on the ... [...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] |
Upstream Contamination
Upstream contamination by floating particles is a paradox, counterintuitive phenomenon in fluid dynamics. When pouring water from a higher container to a lower one, particles floating in the latter can climb upstream into the upper container. A definitive explanation is still lacking: experimental and computational evidence indicates that the contamination is chiefly driven by surface tension gradients, however the phenomenon is also affected by the dynamics of swirling flows that remain to be fully investigated. Origins The phenomenon was observed in 2008 by the Argentine Sebastian Bianchini during Mate (beverage), mate tea preparation, while studying physics at the University of Havana. It rapidly attracted the interest of professor Alejandro Lage-Castellanos, who performed, with Bianchini, a series of controlled experiments. Later on professor Ernesto Altshuler completed the trio in Havana, which resulted in the Diploma thesis of Bianchini and a short original paper posted in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sewage
Sewage (or domestic sewage, domestic wastewater, municipal wastewater) is a type of wastewater that is produced by a community of people. It is typically transported through a sewer system. Sewage consists of wastewater discharged from residences and from commercial, institutional and public facilities that exist in the locality. Sub-types of sewage are greywater (from sinks, bathtubs, showers, dishwashers, and clothes washers) and blackwater (the water used to flush toilets, combined with the human waste that it flushes away). Sewage also contains soaps and detergents. Food waste may be present from dishwashing, and food quantities may be increased where garbage disposal units are used. In regions where toilet paper is used rather than bidets, that paper is also added to the sewage. Sewage contains macro-pollutants and micro-pollutants, and may also incorporate some municipal solid waste and pollutants from industrial wastewater. Sewage usually travels from a building's plum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shower
A shower is a place in which a person bathes under a spray of typically warm or hot water. Indoors, there is a drain in the floor. Most showers have temperature, spray pressure and adjustable showerhead nozzle. The simplest showers have a swivelling nozzle aiming down on the user, while more complex showers have a showerhead connected to a hose that has a mounting bracket. This allows the showerer to hold the showerhead by hand to spray the water onto different parts of their body. A shower can be installed in a small shower stall or bathtub with a plastic shower curtain or door. Showering is common in Western culture due to the efficiency of using it compared with a bathtub. Its use in hygiene is, therefore, common practice. History The original showers were neither indoor structures nor man-made but were common natural formations: waterfalls. The falling water rinsed the bathers completely clean and was more efficient than bathing in a traditional basin, which required m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Float Valve
A ballcock (also balltap or float valve) is a mechanism or machine for filling water tanks, such as those found in flush toilets, while avoiding overflow and (in the event of low water pressure) backflow. The modern ballcock was invented by José Antonio de Alzate y Ramírez, a Mexican priest and scientist, who described the device in 1790 in the ''Gaceta de Literatura Méxicana''. The ballcock device was patented in 1797 for use in steam engines by Edmund Cartwright. It consists of a valve connected to a hollow, sealed float by means of a lever mounted near the top of the tank. The float is often ball-shaped, hence the name ''ballcock''. The valve is connected to the incoming water supply, and is opened and closed by the lever which has the float mounted on the end. When the water level rises, the float rises with it; once it rises to a pre-set level, the mechanism forces the lever to close the valve and shut off the water flow. This is an example of negative feedback and of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cistern
A cistern (Middle English ', from Latin ', from ', "box", from Greek ', "basket") is a waterproof receptacle for holding liquids, usually water. Cisterns are often built to catch and store rainwater. Cisterns are distinguished from wells by their waterproof linings. Modern cisterns range in capacity from a few litres to thousands of cubic metres, effectively forming covered reservoirs. Origins Early domestic and agricultural use Waterproof lime plaster cisterns in the floors of houses are features of Neolithic village sites of the Levant at, for instance, Ramad and Lebwe, and by the late fourth millennium BC, as at Jawa in northeastern Lebanon, cisterns are essential elements of emerging water management techniques in dry-land farming communities. The Ancient Roman impluvium, a standard feature of the domus house, generally had a cistern underneath. The impluvium and associated structures collected, filtered, cooled, and stored the water, and also cooled and ventilated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tundish
The word tundish originates from a shallow wooden dish with an outlet channel, fitting into the bunghole of a tun or cask and forming a kind of funnel for filling it. These were originally used in brewing. In general, any tundish will accept flow and store a small amount of material, while dispensing material elsewhere, similar to a funnel. In contrast to a funnel, the purpose is generally to regulate flow, and achieve a more steady output with intermittent inputs, and the tundish typically will take on a different shape. Plumbing The term tundish is still used today in plumbing, where a funnel or hopper is filled by an outlet pipe above it. This is often provided for intermittent overflows, or where an air gap is required, to avoid possible back-contamination. Metal Casting In metal casting, a tundish is a broad, open container with one or more holes in the bottom. It is used to feed molten metal into an ingot mould to avoid splashing and give a smoother flow. The tundish a ... [...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] |
Fire Sprinkler
A fire sprinkler or sprinkler head is the component of a fire sprinkler system that discharges water when the effects of a fire have been detected, such as when a predetermined temperature has been exceeded. Fire sprinklers are extensively used worldwide, with over 40 million sprinkler heads fitted each year. In buildings protected by properly designed and maintained fire sprinklers, over 99% of fires were controlled by fire sprinklers alone. History In 1812, British inventor Sir William Congreve patented a manual sprinkler system using perforated pipes along the ceiling. When someone noticed a fire, a valve outside the building could be opened to send water through the pipes. It was not until a short time later that, as a result of a large furniture factory that repeatedly burned down, Hiram Stevens Maxim was consulted on how to prevent a recurrence and invented the first automatic fire sprinkler. It would douse the areas that were on fire and report the fire to the fire st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Circulatory System
The blood circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the entire body of a human or other vertebrate. It includes the cardiovascular system, or vascular system, that consists of the heart and blood vessels (from Greek ''kardia'' meaning ''heart'', and from Latin ''vascula'' meaning ''vessels''). The circulatory system has two divisions, a systemic circulation or circuit, and a pulmonary circulation or circuit. Some sources use the terms ''cardiovascular system'' and ''vascular system'' interchangeably with the ''circulatory system''. The network of blood vessels are the great vessels of the heart including large elastic arteries, and large veins; other arteries, smaller arterioles, capillaries that join with venules (small veins), and other veins. The Closed circulatory system, circulatory system is closed in vertebrates, which means that the blood never leaves the network of blood vessels. Some in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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