A valve is a device or natural object that regulates, directs or controls the flow of a fluid by opening, closing, or obstructing various passageways. Valves are technically fittings, but are discussed as a separate category. In an open valve, fluid flows in a direction from higher pressure to lower pressure; the word is derived from the Latin valva, the moving part of a door, in turn from volvere, to turn, roll. The simplest, ancient, valve is a hinged flap which drops to obstruct fluid flow in one direction, but is pushed open by flow in the opposite direction; this is called "checks" the flow in one direction. Modern control valves may regulate pressure or flow downstream and operate on sophisticated automation systems. Valves have many uses, including controlling water for irrigation, industrial uses for controlling processes, residential uses such as on/off and pressure control to dish and clothes washers and taps in the home. Aerosols have a tiny valve built in. Valves are used in the military and transport sectors.
In HVAC ductwork and other near-atmospheric air flows, valves are instead called dampers. In compressed air systems, valves are used with the most common type being ball valves. Valves are found in every industrial process, including water and sewage processing, power generation, processing of oil and petroleum, food manufacturing and plastic manufacturing and many other fields. People in developed nations use valves in their daily lives, including plumbing valves, such as taps for tap water, gas control valves on cookers, small valves fitted to washing machines and dishwashers, safety devices fitted to hot water systems, poppet valves in car engines. In nature there are valves, for example one-way valves in veins controlling the blood circulation, heart valves controlling the flow of blood in the chambers of the heart and maintaining the correct pumping action. Valves may be operated manually, either by a handle, pedal or wheel. Valves may be automatic, driven by changes in pressure, temperature, or flow.
These changes may act upon a diaphragm or a piston which in turn activates the valve, examples of this type of valve found are safety valves fitted to hot water systems or boilers. More complex control systems using valves requiring automatic control based on an external input require an actuator. An actuator will stroke the valve depending on its input and set-up, allowing the valve to be positioned and allowing control over a variety of requirements. Valves vary in form and application. Sizes range from 0.1 mm to 60 cm. Special valves can have a diameter exceeding 5 meters. Valve costs range from simple inexpensive disposable valves to specialized valves which cost thousands of US dollars per inch of the diameter of the valve. Disposable valves may be found in common household items including mini-pump dispensers and aerosol cans. A common use of the term valve refers to the poppet valves found in the vast majority of modern internal combustion engines such as those in most fossil fuel powered vehicles which are used to control the intake of the fuel-air mixture and allow exhaust gas venting.
Valves may be classified into a number of basic types. Valves may be classified by how they are actuated: Hydraulic Pneumatic Manual Solenoid valve Motor The main parts of the most usual type of valve are the body and the bonnet; these two parts form the casing. The valve's body is the outer casing of most or all of the valve that contains the internal parts or trim; the bonnet is the part of the encasing through which the stem passes and that forms a guide and seal for the stem. The bonnet screws into or is bolted to the valve body. Valve bodies are metallic or plastic. Brass, gunmetal, cast iron, alloy steels and stainless steels are common. Seawater applications, like desalination plants use duplex valves, as well as super duplex valves, due to their corrosion resistant properties against warm seawater. Alloy 20 valves are used in sulphuric acid plants, whilst monel valves are used in hydrofluoric acid plants. Hastelloy valves are used in high temperature applications, such as nuclear plants, whilst inconel valves are used in hydrogen applications.
Plastic bodies are used for low pressures and temperatures. PVC, PP, PVDF and glass-reinforced nylon are common plastics used for valve bodies. A bonnet acts as a cover on the valve body, it is semi-permanently screwed into the valve body or bolted onto it. During manufacture of the valve, the internal parts are put into the body and the bonnet is attached to hold everything together inside. To access internal parts of a valve, a user would take off the bonnet for maintenance. Many valves do not have bonnets. Many ball valves do not have bonnets since the valve body is put together in a different style, such as being screwed together at the middle of the valve body. Ports are passages. Ports are obstructed by disc to control flow. Valves most have 2 ports, but may have as many as 20; the valve is always connected at its ports to pipes or other components. Connection methods include threadings, compression fittings, cement, flanges, or welding. A handle is used to manually control a valve from outside the valve body.
Automatically controlled valves do not have h
Weyba Downs is a rural locality in the Sunshine Coast Region, Australia. In the 2016 census, Weyba Downs had a population of 296 people. Weyba Downs is on the Sunshine Coast; the eastern boundary of the locality is the western shore of Lake Weyba, a tidal lake that flows into Noosa River and is within the locality of Noosaville. Weyba is believed to mean "place of stingrays" or "place of flying squirrels". Weyba Downs now covers the area known as Peregian Beach South. In the 2016 census, Weyba Downs had a population of 296 people. "Weyba Downs". Queensland Places. Centre for the Government of Queensland, University of Queensland
"Miracles" is a single by Pet Shop Boys, released in 2003. It was the first single, one of two new songs, from their 2003 singles compilation, PopArt, it peaked at number 10 on the UK Singles Chart. It was co-written by Drum & Bass musicians and Adam F. Orchestration was conducted by Anne Dudley, who would work on Pet Shop Boys' 2006 album Fundamental alongside past musical collaborator Trevor Horn. Remixes were produced by Eric Prydz; the B-side track "We're the Pet Shop Boys" is a cover of a 2002 song recorded by New York band My Robot Friend, in tribute to the Pet Shop Boys themselves. It was covered again by Robbie Williams, with production by the Pet Shop Boys, on his 2006 album Rudebox; the music video, directed by Howard Greenhalgh cost nearly £100,000. It shows human figures interacting with cascades of water and milk, captured in intricate detail by the slow-motion footage; the buildings on the background include Calatrava's Gare do Oriente and others from the Nations' Park area in Lisbon.
"Miracles" "We're the Pet Shop Boys" "Miracles" "Miracles" "Transparent" Official artist site Lyrics of this song at MetroLyrics