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Larner–Johnson Valve
A Larner–Johnson valve is a mechanism used in dams and water pumping to control the flow of water through large pipes. The valve is suited to handling high velocity flow with minimal turbulence, even when partially open, and the actuating force can be provided by the water flow it is controlling. It was manufactured in the early 20th century by the Larner-Johnson Company in the US. The valves are still manufactured in the United Kingdom by Blackhall Engineering Ltd. These valves have been constructed in sizes up to diameter and controlling a hydraulic head of . In 2009, Blackhall Engineering supplied four 60" bore Larner–Johnson valves to New York City Department of Environmental Protection for the Ashokan Reservoir in upstate New York. Each valve is capable of passing a flow rate of 19 cubic metres/second, which is the equivalent of 19 tons of water per second. The valves control the flow of water out of the Ashokan Reservoir into the Catskill Aqueduct down to N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydraulic Head
Hydraulic head or piezometric head is a specific measurement of liquid pressure above a vertical datum., 410 pages. See pp. 43–44., 650 pages. See p. 22. It is usually measured as a liquid surface elevation, expressed in units of length, at the entrance (or bottom) of a piezometer. In an aquifer, it can be calculated from the depth to water in a piezometric well (a specialized water well), and given information of the piezometer's elevation and screen depth. Hydraulic head can similarly be measured in a column of water using a standpipe piezometer by measuring the height of the water surface in the tube relative to a common datum. The hydraulic head can be used to determine a ''hydraulic gradient'' between two or more points. "Head" in fluid dynamics In fluid dynamics, ''head'' is a concept that relates the energy in an incompressible fluid to the height of an equivalent static column of that fluid. From Bernoulli's principle, the total energy at a given point in a flui ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New York City Department Of Environmental Protection
The New York City Department of Environmental Protection (DEP) is the department of the government of New York City that manages the city's water supply and works to reduce air, noise, and hazardous materials pollution. Under a 1.3 billion dollar budget, it provides more than of water each day to more than 9 million residents (including 8 million in the City of New York) through a complex network of nineteen reservoirs, three controlled lakes and of water mains, tunnels and aqueducts. DEP is also responsible for managing the city's combined sewer system, which carries both storm water runoff and sanitary waste, and fourteen wastewater treatment plants located throughout the city. DEP carries out federal Clean Water Act rules and regulations, handles hazardous materials emergencies and toxic site remediation, oversees asbestos monitoring and removal, enforces the city's air and noise codes, bills and collects on city water and sewer accounts, and manages citywide water ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ashokan Reservoir
The Ashokan Reservoir (; Iroquois for "place of fish") is a reservoir in Ulster County, New York. It is at the eastern end of the Catskill Park, and is one of several in the region created to provide the City of New York with water. It is the city's deepest reservoir at near the dam at the former site of Bishop Falls. History New York City turned to the Catskills for water in the early 20th century after discovering that a group of speculators calling itself the Ramapo Water Company had bought up riparian rights to many water sources further south in Rockland, Orange and Ulster counties. The Catskills were more desirable, as state-owned Forest Preserve land in the region could not, under the state constitution, be sold to any other party. A recent amendment to that section of the state constitution also allowed up to 3 percent of the total Forest Preserve land to be flooded for reservoirs. In 1905 the New York State Legislature enacted legislation that created the New York ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catskill Aqueduct
The Catskill Aqueduct, part of the New York City water supply system, brings water from the Catskill Mountains to Yonkers where it connects to other parts of the system. History Construction commenced in 1907. The aqueduct proper was completed in 1916 and the entire Catskill Aqueduct system including three dams and 67 shafts was completed in 1924. The total cost of the aqueduct system was $177 million (). Specifications The aqueduct consists of of cut and cover aqueduct, over of grade tunnel, of pressure tunnel, and nine miles (10 km) of steel siphon. The 67 shafts sunk for various purposes on the aqueduct and City Tunnel vary in depth from 174 to . Water flows by gravity through the aqueduct at a rate of about . The Catskill Aqueduct has an operational capacity of about per day north of the Kensico Reservoir in Valhalla, New York. Capacity in the section of the aqueduct south of Kensico Reservoir to the Hillview Reservoir in Yonkers, New York is per day. The a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Penstock
A penstock is a sluice or gate or intake structure that controls water flow, or an enclosed pipe that delivers water to hydro turbines and sewerage systems. The term is inherited from the earlier technology of mill ponds and watermills. Hydroelectric systems and dams Penstocks for hydroelectric installations are normally equipped with a gate system and a surge tank. They can be a combination of many components such as anchor block, drain valve, air bleed valve, and support piers depending on the application. Flow is regulated by turbine operation and is nil when turbines are not in service. Penstocks, particularly where used in polluted water systems, need to be maintained by hot water washing, manual cleaning, antifouling coatings, and desiccation. The term is also used in irrigation dams to refer to the channels leading to and from high-pressure sluice gates. Penstocks are also used in mine tailings dam construction. The penstock is usually situated fairly clos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Servomechanism
In control engineering a servomechanism, usually shortened to servo, is an automatic device that uses error-sensing negative feedback to correct the action of a mechanism. On displacement-controlled applications, it usually includes a built-in encoder or other position feedback mechanism to ensure the output is achieving the desired effect. The term correctly applies only to systems where the feedback or error-correction signals help control mechanical position, speed, attitude or any other measurable variables. For example, an automotive power window control is not a servomechanism, as there is no automatic feedback that controls position—the operator does this by observation. By contrast a car's cruise control uses closed-loop feedback, which classifies it as a servomechanism. Applications Position control A common type of servo provides ''position control''. Commonly, servos are electric, hydraulic, or pneumatic. They operate on the principle of negative feedback, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bernoulli's Principle
In fluid dynamics, Bernoulli's principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in static pressure or a decrease in the fluid's potential energy. The principle is named after the Swiss mathematician and physicist Daniel Bernoulli, who published it in his book ''Hydrodynamica'' in 1738. Although Bernoulli deduced that pressure decreases when the flow speed increases, it was Leonhard Euler in 1752 who derived Bernoulli's equation in its usual form. The principle is only applicable for isentropic flows: when the effects of irreversible processes (like turbulence) and non- adiabatic processes (e.g. thermal radiation) are small and can be neglected. Bernoulli's principle can be applied to various types of fluid flow, resulting in various forms of Bernoulli's equation. The simple form of Bernoulli's equation is valid for incompressible flows (e.g. most liquid flows and gases moving at low Mach number). More advanced forms may be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Double-acting Piston
In mechanical engineering, the cylinders of reciprocating engines are often classified by whether they are single- or double-acting, depending on how the working fluid acts on the piston. Single-acting A single-acting cylinder in a reciprocating engine is a cylinder in which the working fluid acts on one side of the piston only. A single-acting cylinder relies on the load, springs, other cylinders, or the momentum of a flywheel, to push the piston back in the other direction. Single-acting cylinders are found in most kinds of reciprocating engine. They are almost universal in internal combustion engines (e.g. petrol and diesel engines) and are also used in many external combustion engines such as Stirling engines and some steam engines. They are also found in pumps and hydraulic rams. Double-acting A double-acting cylinder is a cylinder in which the working fluid acts alternately on both sides of the piston. In order to connect the piston in a double-acting cylinder to an ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pilot Valve
A pilot valve is a small valve that controls a limited-flow control feed to a separate piloted valve. Typically, this separate valve controls a high pressure or high flow feed. Pilot valves are useful because they allow a small and easily operated feed to control a much higher pressure or higher flow feed, which would otherwise require a much larger force to operate; indeed, this is even useful when a solenoid upright=1.20, An illustration of a solenoid upright=1.20, Magnetic field created by a seven-loop solenoid (cross-sectional view) described using field lines A solenoid () is a type of electromagnet formed by a helix, helical coil of wire whose ... is used to operate the valve. Pilot valves are often used in critical applications (e.g., emergency and SIS controls) and are human-operated. They can be set up as a push-to-activate or dead man's switch. See also * Larner–Johnson valve * Pilot-operated relief valve Valves {{tech-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power Station Technology
Power most often refers to: * Power (physics), meaning "rate of doing work" ** Engine power, the power put out by an engine ** Electric power * Power (social and political), the ability to influence people or events ** Abusive power and control, Abusive power Power may also refer to: Mathematics, science and technology Computing * IBM POWER (software), an IBM operating system enhancement package * IBM POWER architecture, a RISC instruction set architecture * Power ISA, a RISC instruction set architecture derived from PowerPC * IBM Power microprocessors, made by IBM, which implement those RISC architectures * Power.org, a predecessor to the OpenPOWER Foundation * SGI POWER Challenge, a line of SGI supercomputers Mathematics * Exponentiation, "''x'' to the power of ''y''" * Power function * Power of a point * Statistical power Physics * Magnification, the factor by which an optical system enlarges an image * Optical power, the degree to which a lens converges or diverges light ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
