query: what is a saddle valve on a water line

pos: Saddle valve Saddle valve A saddle valve is a valve used to supply liquid where a low volume, low pressure stream is required. The name is derived from the fact that it is mounted in such a way that it "saddles" the line, mounting it from both sides. They are typically used for supplying cold water, via a 3/8 inch tube, to: A saddle valve is mounted directly on to a pipe which is usually 1/2 inch copper tubing. Saddle valves are self-tapping devices. Once mounted on a line, with the included rubber seal in place, all that is required is to

pos: Saddle valve Saddle valve A saddle valve is a valve used to supply liquid where a low volume, low pressure stream is required. The name is derived from the fact that it is mounted in such a way that it "saddles" the line, mounting it from both sides. They are typically used for supplying cold water, via a 3/8 inch tube, to: A saddle valve is mounted directly on to a pipe which is usually 1/2 inch copper tubing. Saddle valves are self-tapping devices. Once mounted on a line, with the included rubber seal in place, all that is required is to

pos: Saddle valve turn the valve clockwise until it pierces the water line. When the valve handle can no longer be turned, it is done tapping the pipe. Turning the handle counter-clockwise opens the valve. These valves can be installed without shutting off the main water supply. Plumbing codes, local or international, often do not allow use of a saddle valve; instead a tee and a conventional globe, gate, or ball valve is to be installed. Saddle valve A saddle valve is a valve used to supply liquid where a low volume, low pressure stream is required. The name is derived from the

neg: Tank locomotive side tanks that run the length of the smokebox, instead of the full length of the boiler. They were mainly used on narrow gauge industrial locomotives that could be frequently re-filled with water and where side or saddle tanks would restrict access to inside valve gear. See Kerry Tramway "Excelsior" which has been described, by various sources, as both a wing tank and an inverted saddle tank. The inverted saddle tank was a variation of the Wing Tank where the two tanks were joined underneath the smokebox and supported it. This rare design was used for the same reasons as

neg: Pressure-balanced valve water faucet elsewhere, the relatively higher pressure in the cold water supply line will cause the shower temperature to drop suddenly. The pressure-balanced shower valve compensates for changes in water pressure. It has a diaphragm or piston inside that reacts to relative changes in either hot or cold water pressure to maintain balanced pressure. As water pressure drops on one supply line, the valve reduces the pressure in the other supply line to match. A side effect of this is that the pressure and flow at the shower head or tub spigot will drop twice as much as if only

neg: Joel Hurt center by his Atlanta and Edgewood Street Railway Company, which opened along Edgewood Avenue in 1886. It was Atlanta's first electric streetcar line, and it was the first profitable electric line in America. In 1880, he filed what would be for an interesting thermal water valve. Then in 1887, he filed No. 374,188 for a new style of valve cock for faucets handling water under pressure. To anchor the downtown end of his streetcar line, he built Atlanta's first skyscraper, the Equitable Building, which in 1893 became the home of the two-year-old Trust Company. His next land deal was to

neg: Water hammer some shuddering. On the other hand, when an upstream valve in a pipe closes, water downstream of the valve attempts to continue flowing creating a vacuum that may cause the pipe to collapse or implode. This problem can be particularly acute if the pipe is on a downhill slope. To prevent this, air and vacuum relief valves or air vents are installed just downstream of the valve to allow air to enter the line to prevent this vacuum from occurring. Other causes of water hammer are pump failure and check valve slam (due to sudden deceleration, a check valve may

neg: Diaphragm valve "weir" (saddle) and the other (sometimes called a "full bore or straight-way" valve) seals over a seat. The weir or saddle type is the most common in process applications and the seat-type is more commonly used in slurry applications to reduce blocking issues but exists also as a process valve. While diaphragm valves usually come in two-port forms (2/2-way diaphragm valve), they can also come with three ports (3/2-way diaphragm valves also called T-valves) and more (so called block-valves). When more than three ports are included, they generally require more than one diaphragm seat; however, special dual actuators can handle

neg: W. G. Bagnall locomotive valve gear including the Baguley and the Bagnall-Price. They also used marine (circular) fireboxes on narrow gauge engines, a design that was cheap but needed a different firing technique. Bagnall also developed the inverted saddle tank. The two tanks were joined underneath the smokebox and supported the smokebox. Bagnall also commonly used the saddle tank which carries the water on top of the boiler. Bagnalls also produced pannier tank locomotives such as the GWR 5700 Class of which Bagnall produced 100 of the class for the Great Western Railway from 1930 under lot number 262 and in 1931 under

neg: South African Class NG2 0-4-2ST 0-4-2 saddle-tank steam locomotives, built by Dickson Manufacturing Company of Scranton in Pennsylvania shortly before it merged with seven other manufacturing firms to form the American Locomotive Company (ALCO) in 1901, were delivered to various gold mines on the Witwatersrand by Arthur Koppel, acting as importing agent. The engines had bar frames, with the cylinders arranged outside the frames and actuated by Stephenson valve gear. Their saddle-tanks had a water capacity. Their operating boiler pressure was set at and they had a tractive effort at 75% of boiler pressure. In 1915, shortly after the outbreak of the First World War,

neg: Solenoid valve and large orifices are encountered, then high forces are required. To generate those forces, an internally piloted solenoid valve design may be possible. In such a design, the line pressure is used to generate the high valve forces; a small solenoid controls how the line pressure is used. Internally piloted valves are used in dishwashers and irrigation systems where the fluid is water, the pressure might be and the orifice diameter might be . In some solenoid valves the solenoid acts directly on the main valve. Others use a small, complete solenoid valve, known as a pilot, to actuate a

neg: Marine aquarium marine as well as freshwater livestock. First, the fish is placed with all the bag water in a bucket or container of sufficient size for the fish to be reasonably covered with the water, and the bucket is then set on the floor next to the aquarium. Using some plastic air line tubing and an air gang valve, a siphon drip line is set up from the aquarium to the bucket. Tank water is allowed to drip slowly into the bucket, using the gang valve to adjust the drip rate, until the water dripped into the bucket equals about two

neg: Ballcock may be a flapper valve, which is designed to sink more slowly than the water, which will exit to the toilet bowl below, so that the tank may empty. As the tank water level drops, the float descends and actuates the fill valve. Water is fed to the tank to replenish its supply, and a smaller flow is directed into the overflow tube to refill the bowl. Once the flapper valve closes, the water flow from the fill valve continues until the tank level again reaches the fill line. Another discharge mechanism, common in the United Kingdom, is a siphon

neg: Entracque Power Plant dam, called Colle Laura, directly to its east. The saddle dam is also equipped with a spillway that has a discharge capacity of . The storage capacity of the reservoir is while can be used for power generation. The catchment area for Chiotas is and the reservoir reaches a maximum depth of . When power generation is required, water is released from either upper reservoir back down to the power station and its generators. The power station is located underground and consists of transformer, valve gallery and generator hall caverns. From the Chiotas reservoir, water is sent back through a

neg: Circulator pump at the farthest fixture from the water heater and closes once hot water contacts the valve to control crossover flow between the hot and cold lines. A second type of system uses a thermostatically controlled pump which gets installed at the farthest fixture from the water heater. These thermostatically controlled pumps often have a built-in "normally closed" check-valve which prevents water in the cold water line from entering into the hot water line. Compared to a dedicated return line, using the cold water line as a return has the disadvantage of heating the cold water pipe (and the contained water).

neg: Pressure-balanced valve Pressure-balanced valve A pressure-balanced valve provides water at nearly constant temperature to a shower or bathtub, despite pressure fluctuations in either the hot or cold supply lines. If, for example, someone flushes a toilet while the shower is in use, the fixture suddenly draws a significant amount of cold water from the common supply line, causing a pressure drop. In the absence of a compensating mechanism, the relatively higher pressure in the hot water supply line will cause the shower temperature to rise just as suddenly, possibly reaching an uncomfortable or even dangerous level. Conversely, if someone opens a hot

neg: Plumbing fixture is plugged, before the water actually overflows at the flood rim level. However, water closets and showers (that are not in bathtubs) usually lack this feature because their drains normally cannot be stopped. Each fixture usually has a characteristic means of connection. Normal plumbing practice is to install a valve on each water supply line before the fixture, and this is most commonly termed a "stop" or "service valve". The water supply to some fixtures is cold water only (such as water closets and urinals). Most fixtures also have a hot water supply. In some occasional cases, a sink may

neg: Vauclain compound Vauclain compound The Vauclain compound was a type of compound steam locomotive that was briefly popular around 1900. Developed at the Baldwin Locomotive Works, it featured two pistons moving in parallel, driving a common crosshead and controlled by a common valve gear using a single, complex piston valve. The claimed advantage for this arrangement, as with other compounding arrangements, was greater economy due to lower fuel and water consumption. In practice uneven forces at the crosshead produced excess wear, with increased maintenance costs thus offsetting any fuel economies. The integration of the compounding system into the smokebox saddle made conversion

neg: Valve of a single handle. "Thermostatic mixing valves" mix hot and cold water to produce a constant temperature in the presence of variable pressures and temperatures on the two input ports. A 4-port valve is a valve whose body has four ports equally spaced round the body and the disc has two passages to connect adjacent ports. It is operated with two positions. It can be used to isolate and to simultaneously bypass a sampling cylinder installed on a pressurized water line. It is useful to take a fluid sample without affecting the pressure of a hydraulic system and to avoid

neg: SECR K and SR K1 classes as the shape of the cab and the drumhead-type smokebox, which sat on a saddle that was of wider diameter than the fully lagged and clad boiler. The latter was fitted with Ross pop safety valves and pressed to . Other innovations by Maunsell's team included greater superheating surface area, locating the boiler water top feed inside a dome-like cover with external clackboxes and water feed pipes mounted on either side, outside Walschaerts valve gear, and parts that could be shared with similar locomotive classes to reduce maintenance costs. The firebox was narrower towards the rear and featured a continuously

neg: Hot tapping tap for the installation of a variety of ports, valves, t-sections or other pipes. Hot Tap Procedures: A. Hot Tap Saddle or weld nozzle installed, valve installed, assembly is pressure tested and hot tap machine attached. B. Valve opened, hot tap completed, coupon or cut portion retained by latches on pilot drill. Pressure is contained within the hot tapping machine. C. Cutter and coupon retracted and valve closed. Fluid is drained and hot tapping machine is removed. The tapped valve is now ready for the contractor’s tie-in or IFT’s linestop/stopple equipment to be inserted. Hot tapping is also the first

neg: Diaphragm valve Diaphragm valve Diaphragm valves (or membrane valves) consists of a valve body with two or more ports, a diaphragm, and a "weir or saddle" or seat upon which the diaphragm closes the valve. The valve body may be constructed from plastic, metal, wood or other materials depending on the intended use. Originally, the diaphragm valve was developed for use in industrial applications and/or pipe-organs. Later on the design was adapted for use in the bio-pharmaceutical industry by using compliant materials that can withstand sanitizing and sterilizing methods. There are two main categories of diaphragm valves: one type seals over a

neg: Four-way valve Four-way valve The four-way valve or four-way cock is a fluid control valve whose body has four ports equally spaced round the valve chamber and the plug has two passages to connect adjacent ports. The plug may be cylindrical or tapered, or a ball. It has two flow positions as shown, and usually a central position where all ports are closed. It can be used to isolate and to simultaneously bypass a sampling cylinder installed on a pressurized water line. It is useful to take a fluid sample without affecting the pressure of a hydraulic system and to avoid degassing

neg: Bradford Industrial Museum material, and thereafter coal and construction material, then coal and other materials until 1970 when she was loaned to the Yorkshire Dales Railway Society at Skipton. Her size is ca.23 x 8 x 11 ft, and she weighs 28 tons. The boiler works at 160psi, and she carries 700 gallons in the saddle water tank. The cylinders are 40-inch diameter 20-inch stroke operated by Stephenson's open link valve gear. A British Railways Crane Wagon is on display outside near the museum gates. In the tram shed is the only tramcar left in Bradford, and a Bradford trolleybus. The first horse-drawn

neg: Siphon valve is also required here to prevent pressure drops in the water supply line from suctioning water out of the toilet tank (which may contain additives such as "toilet blue") and contaminating the water system. Anti-siphon valves function as a one-direction check valve. Anti-siphon valves are also used medically. Hydrocephalus, or excess fluid in the brain, may be treated with a shunt which drains cerebrospinal fluid from the brain. All shunts have a valve to relieve excess pressure in the brain. The shunt may lead into the abdominal cavity such that the shunt outlet is significantly lower than the shunt

neg: Hydraulic ram allow a valve design that enables rapid closure and with a relatively small cross sectional area and low weight. The venturi valve is configured as a ring section positioned around the supply inlet of the pump with the delivery outlet of the pump being directly in line. The design allowed the pump structure to be concentric and therefore inherently strong and upon closure of the valve, permits efficient water delivery by acting in line with the supply via a second smaller venturi effect delivery non return valve. The elastomeric material and operation of these valves also allows them to self-return

neg: Anomia (bivalve) Anomia (bivalve) Anomia is a genus of saltwater clams, marine bivalve mollusks in the family Anomiidae. They are commonly known as jingle shells because when a handful of them are shaken they make a jingling sound, though some are also known as saddle oysters. This genus first appeared in the Permian period of China, Italy, and Pakistan. "Anomia" species are common in both tropical and temperate oceans and live primarily attached to rock or other shells via a calcified byssus that extends through the lower valve. "Anomia" shells tend to take on the surface shape of what they are attached

neg: Bivalve shell parts. The mantle itself is attached to the shell by numerous small mantle retractor muscles, which are arranged in a narrow line along the length of the interior of the shell. The position of this line is often quite clearly visible on the inside of each valve of a bivalve shell, as a shiny line, the pallial line, which runs along a small distance in from the outer edge of each valve, usually joining the anterior adductor muscle scar to the posterior adductor muscle scar. The adductor muscles are what allow the bivalve to close the shell tightly. In some

neg: Pododesmus patelliformis Pododesmus patelliformis Pododesmus patelliformis or ribbed saddle-oyster is a species of bivalve mollusc in the family Anomiidae. It is found in the north east Atlantic Ocean. This oyster has a thin asymmetric shell up to four centimetres in length which is white, sometimes with brown markings. The outline is roughly circular and the beaks are central but set back from the margin. The upper valve is sculptured with up to sixty weak radial riblets, and the inside is glossy white or tinged yellowish-green with two distinct, furrowed muscle scars on the upper valve. The lower valve is flat, thin, transparent

neg: The Standing Rock Rural Water System gallon ground storage reservoir. Currently, (in December 2016) the intake valve for the water system is "located in a shallow part of the Missouri River near Fort Yates, North Dakota, roughly 20 miles from the planned river crossing of the controversial Dakota Access Pipeline also known as the Bakken pipeline. The Bakken oil pipeline Dakota line is to be "buried below the riverbed in hard clay." A new valve came online in 2016 in Mobridge, South Dakota which is seventy miles south of the proposed Bakken Pipeline Missouri River crossing. This Mobridge intake valve is intended to service the entire

neg: Leith Saddle Leith Saddle Leith Saddle is a saddle between the sources of the Water of Leith and the Waitati River, approximately halfway between Dunedin's northern suburb of Pine Hill and the outlying settlement of Waitati. The saddle is a strategic point where the Dunedin Northern Motorway, part of State Highway 1 traverses a fragile alpine forest. Proposed road works to straighten a dangerous corner here conflict with conservation values. Water supply pipelines, and popular tramping and cycling routes also converge at the saddle. The Water of Leith's source is 100 metres to the south of Leith Saddle, at a height of

neg: Circulator pump utilize the cold water line to return water back to the water heater. Hot Water Line Siphoning occurs when water from within the hot water line siphons or is forced into the cold water line due to differences in water pressure between the hot and cold water lines. Utilizing "normally closed" solenoid valve significantly reduces energy consumption by preventing siphoning of non-hot water out of hot water lines during cold water use. Using cold water instantly lowers the water pressure in the cold water lines, the higher water pressure in the hot water lines force water through "normally open" thermostatic

neg: Rack and pinion large water pipeline. In the top actuator, a gray control signal line can be seen connecting to a solenoid valve (the small black box attached to the back of the top actuator), which is used as the pilot for the actuator. The solenoid valve controls the air pressure coming from the input air line (the small green tube). The output air from the solenoid valve is fed to the chamber in the middle of the actuator, increasing the pressure. The pressure in the actuator's chamber pushes the pistons away. While the pistons are moving apart from each other, the attached

neg: Circulator pump pipes. Thermal insulation applied to the pipes helps mitigate this second loss and minimize the amount of water that must be pumped to keep hot water constantly available. The traditional hot water recirculation system uses a dedicated return line from the point of use located farthest from the hot water tank back to the hot water tank. In homes where this return line was not installed the cold water line is used as a return line. The first of two system types has a pump mounted at the hot water heater while a "normally open" thermostatic control valve gets installed

neg: Deaerator section. Should this vent valve not be opened sufficiently the deaerator will not work properly, causing high oxygen content in the feed water going to the boilers. Should the boiler not have an oxygen-content analyser, a high level in the boiler chlorides may indicate the vent valve not being far enough open. Some designs may include a vent condenser to trap and recover any water entrained in the vented gas. The vent line usually includes a valve and just enough steam is allowed to escape with the vented gases to provide a small visible telltale plume of steam. The deaerated

neg: Stalemate in Southern Palestine stood in line, with their saddle cloths spread out on the sand in front of them. On each saddle cloth, in similar positions, lay each man’s full equipment of about 25 separate items, all cleaned and polished up to the nines—saddles, stirrups and irons, bridles and bits, water bottles, feed bags, greatcoats, saddle bags, dixies, etc. etc." On Friday 17 August, the Division moved back to El Fukhan. "Six men on leave to Port Said." The New Zealand Mounted Rifle Brigade arrived at Tel el Marakeb the next day for a fortnight on the beach before they returned to El

neg: Water key Water key A water key is a valve or tap used to allow the drainage of accumulated fluid from wind instruments. It is otherwise known as a water valve or, less euphemistically, a spit valve. In valved instruments like trumpets, they are found always on the main tuning slide, and sometimes on valve slides. On the trombone, it is on the lower side of the bend in the hand slide. Baritone saxophones have a water key at the bottom of the loop at the top of the instrument. Water valves are often erroneously referred to as "spit valves", as the

neg: Buffalo Box in Buffalo, New York. Buffalo Box A curb box (also known as a valve box, buffalo box, or b-box) is a vertical cast iron sleeve, accessible from the public way, housing the shut-off valve (curb cock or curb stop) for a property's water service line. It is typically located between a building and the district's water main lines and usually consists of a metal tube with a removable or sliding lid, allowing access to the turn-key within. It typically serves as the point denoting the separation of utility-maintained and privately-maintained water facilities. A curb box is often called a "Buffalo

neg: Buffalo Box Buffalo Box A curb box (also known as a valve box, buffalo box, or b-box) is a vertical cast iron sleeve, accessible from the public way, housing the shut-off valve (curb cock or curb stop) for a property's water service line. It is typically located between a building and the district's water main lines and usually consists of a metal tube with a removable or sliding lid, allowing access to the turn-key within. It typically serves as the point denoting the separation of utility-maintained and privately-maintained water facilities. A curb box is often called a "Buffalo Box", because it originated

neg: Tap (valve) applications for coarse control of the release of fuel gases (such as natural gas, coal gas, and syngas). Like all ball valves its handle will parallel the gas line when open and be perpendicular when closed, making for easy visual identification of its status. Water and gas taps have adjustable flow: gate valves are more progressive; ball valves more coarse, typically used in on-off applications. Turning a valve knob or lever adjusts flow by varying the aperture of the control device in the valve assembly. The result when opened in any degree is a choked flow. Its rate is independent

neg: Route of All Evil Tour at every show have been: "Cryin'", "Stop Messin' Around", "Seasons of Wither" (with "Hangman Jury" as an intro occasionally), "Sweet Emotion", "Draw the Line" and "Walk This Way". Other songs played included "Toys in the Attic", "Eat the Rich", "Love in an Elevator", "Jaded", "Mama Kin", "S.O.S. (Too Bad)", "Dude (Looks Like a Lady)", "Walkin' the Dog", "Big Ten Inch Record", "Baby, Please Don't Go", "What It Takes", "Rag Doll", "Dream On", "Back in the Saddle", "Last Child", "No More No More", "Lord of the Thighs", "Pink", "Rattlesnake Shake, "Train Kept A-Rollin'", "Dirty Water", "One Way Street", "Livin' on the

neg: Larner–Johnson valve water pressure is bled away through a drain valve, obviously that will reduce its pressure too. Internally the fixed valve body is constructed as a cylinder, with the moving part of the valve within this as a piston. The conical valve is part of this piston. The piston is double-acting and splits the internal valve body in two, with water pressure on both sides. The upper side of the piston is larger, the full diameter of the piston, and is supplied with water through a throttling valve; normally adjusted and then left in position. The lower side of the piston

neg: Full face diving mask connector (Ocean Reef) or by bayonet style connector (Draeger). These allow for bailout or decompression gas to be ported to the mask via an entirely independent scuba set, but it is necessary to control which gas is used at any given time by using a valve on the supply line or cylinder. The Draeger Panorama mask also allows the primary demand valve to be unplugged from the mask and a bailout demand valve to be substituted. This can be done underwater with very little water ingress to the mask, and is closely equivalent to switching demand valves with a half

neg: GWR 0-6-0PT GWR 0-6-0PT The GWR 0-6-0PT (Pannier Tank), is a type of steam locomotive built by the British Great Western Railway with the water tanks carried on both sides of the boiler, in the manner of panniers. They were used for local, suburban and branch line passenger and goods traffic, for shunting duties, and as banker engines on inclines. The early examples, such as the 1901 and 2021 classes, were rebuilt from saddle or side tanks when the locos received a Belpaire firebox – this type of firebox has a square top and is incompatible with a curved saddle tank. This

neg: Prospect Reservoir Valve House or gaudiness., The Valve chambers are lined with crafted brickwork, and much of the valve gear is original, although some components have been renewed. Where this has occurred, the original style and appearance have been preserved. In addition, the valve house contains what is thought to be the original weight operated "Kent " flow metres, renowned for their accuracy and reliability (this would need to be substantiated by formal investigation)., The Pumping station is a central controlling structure in the Upper Nepean Scheme, regulating the release of water from Prospect Reservoir (maximum rate 450 megalitres/day) to the Lower Canal for

neg: Leith Saddle supply reservoirs in Leith Valley: Ross Creek Reservoir and Sullivans Dam. Treated, fluoridated water is transmitted northwards from Dunedin's municipal water system via a new pipeline to the rural settlements of Waitati, Warrington and Seacliff. Leith Saddle Leith Saddle is a saddle between the sources of the Water of Leith and the Waitati River, approximately halfway between Dunedin's northern suburb of Pine Hill and the outlying settlement of Waitati. The saddle is a strategic point where the Dunedin Northern Motorway, part of State Highway 1 traverses a fragile alpine forest. Proposed road works to straighten a dangerous corner here conflict

neg: Larner–Johnson valve is an annular space surrounding the moving valve body and maintained at the lower (Bernoulli) water pressure. The tip of the conical valve contains a small pilot valve, linking the upper chamber of the valve to the downstream drain below the valve. This pilot valve is controlled mechanically from outside the valve chamber and is the main control over the valve position. When water pressure builds up in the upper chamber, through the throttle valve, this forces the valve downstream and closes it against the seat. As the area of the piston on this side is larger, the pressure easily

neg: Water timer Water timer A water timer is an electromechanical device that, when placed on a water line, increases or decreases the water flow through the use of an embedded (solenoid) valve. It is used in conjunction with irrigation sprinklers to form an automated or non-automated sprinkler system, capable of administering precise amounts of water, at a regular basis. An alternative to a water timer to administer precise amounts of water at a regular basis, is to precisely calculate the needed waterflow and arrange a system composed by a Time switch and an electric pump that. The electric pump is to be

neg: Kingston valve Kingston valve A Kingston valve is a type of valve fitted in the bottom of a ship's plating that connects the sea to the ship's piping and storage tanks. A Kingston valve is a type of seacock. It is arranged so that, under normal operating conditions, sea pressure keeps the valve closed. When opened from the ship's interior, the Kingston valve allows sea water to enter the tank. The mechanism is named after its inventor John Kingston (1786–1847), an English engineer. On surface ships, Kingston valves are fitted on ship systems such as fuel tanks, water tanks, and ballast tanks.

neg: Lifting bag the bag so that the bag will be completely filled. Dump valves are used to release air from the bag when in the water. They can be operated manually at the valve by a diver or may be remotely operated by a pull-cord, which may be operated by a diver or attached to a weight which will automatically open the valve if the weight is lifted off the bottom. Some dump valves can be operated in both these ways. One system operates by pressing on the top or pulling a line attached to the bottom to actuate the spring-loaded valve.

neg: Pressure-balanced valve one supply line had been affected, but without a large temperature change. There are ball bearings in the valves to regulate forces. The use of pressure-balanced valves can prevent scalding injuries, in particular to the elderly, the infirm, to children and infants. Based on that, some municipalities require by building codes to have it installed. Pressure-balanced valve A pressure-balanced valve provides water at nearly constant temperature to a shower or bathtub, despite pressure fluctuations in either the hot or cold supply lines. If, for example, someone flushes a toilet while the shower is in use, the fixture suddenly draws a

neg: Line stopping – 80” in size. Line Stops can be performed on almost any kind of pipe with pressures or product under pressure including all types of pipe materials, e.g.: Line stopping Line stopping or line plugging is a means of isolating a piping system to provide a shut off where none exists. This process serves as a control, or temporary valve, that can be removed after alterations or valve replacements have been made. With a "hot tap" previously made on a line, a line stopper is attached to a temporary valve, and the valve is opened. The line stopper is hydraulically

neg: Relay valve intersection. With a service brake relay valve installed, the hose that connects to the primary delivery-port output of the foot-valve becomes a control-line (i.e., The air from the foot-valve “dead ends” at the relay valve's control-port.). Only low-volume air-signals are required to travel back and forth between the foot-valve's delivery port and the relay valve's control port; therefore, the air-volume supplied by the delivery port is now only a "tiny-fraction" of what otherwise would have been required had the relay valve not been installed. This reduces the delay between the application of the front and rear brakes to only a

neg: Line stopping Line stopping Line stopping or line plugging is a means of isolating a piping system to provide a shut off where none exists. This process serves as a control, or temporary valve, that can be removed after alterations or valve replacements have been made. With a "hot tap" previously made on a line, a line stopper is attached to a temporary valve, and the valve is opened. The line stopper is hydraulically or mechanically pushed into the line to seal the pipe. The main is supported by the line stop sleeve. After performing the necessary service, the stop is removed,

neg: Mitral valve away from the free margin. This disposition has important effects on systolic stress distribution physiology The mitral annulus is a fibrous ring that is attached to the mitral valve leaflets. Unlike prosthetic valves, it is not continuous. The mitral annulus is saddle shaped and changes in shape throughout the cardiac cycle. The annulus contracts and reduces its surface area during systole to help provide complete closure of the leaflets. Expansion of the annulus can result in leaftlets that do not join soundly together, leading to functional mitral regurgitation. The normal diameter of the mitral annulus is , and the circumference

neg: Vespa Cosa minor differences. Firstly, the clutch was modified so that it would be easier to pull in and release. Secondly, minor design alterations were made: the tail light was slightly different and moved to a new position, the seat lock was installed on the side of the saddle, and the saddle was widened for extra comfort. While the engine is virtually identical to that of the Vespa PX series of the time, there are three major differences in the design: In addition, the carburetor on the Vespa Cosa came stock fitted with an electronic fuel valve and automatic choke. It also

neg: Mitral valve annuloplasty are believed to be key to optimize leaflet coaptation and to minimize tissue stresses. The challenge of mitral valve annuloplasty is to improve the diseased and distorted shape of the mitral valve and to reestablish the physiological configuration, while preserving normal annular dynamics. Today, cardiac surgeons can select from a variety of annuloplasty devices, flexible, semi-rigid, or rigid, incomplete or complete, planar or saddle-shaped, adjustable and non-adjustable. While the general goal of all devices is the same, namely to increase leaflet coaptation and to support the posterior annulus against dilation, flexible bands are designed to maintain the three-dimensional contour of

neg: Water timer arranged to be turned on and off at regular intervals by the time switch to administer (fairly) precise and regular water quantities. This approach, used frequently in DIY watering systems, allows financial savings as the water timer can be discarded. For high-end applications however, water timers sometimes allow more flexibility and more options. Water timer A water timer is an electromechanical device that, when placed on a water line, increases or decreases the water flow through the use of an embedded (solenoid) valve. It is used in conjunction with irrigation sprinklers to form an automated or non-automated sprinkler system, capable

neg: Rhynchonellida (the long middle section) of the shell. This probably helps regulate the flow of water in and out of the shell. All rhynchonellids are biconvex (have a bulbous shell), and have a fold located in the brachial valve. This means that the commissure, the line between the two valves or shells, is zigzagged, a distinguishing characteristic of this group. The prominent beak of the pedicle valve usually overlaps that of the brachial valve, in order to allow the shell to open and close. There is usually a functional pedicle although the delthyrium may be partially closed. Morphologically, the rhynchonellid has

neg: Gooseneck (piping) Goosenecks (also referred to as pigtails) are in-line components of a water service (i.e. piping, valves, fittings, tubing, and accessories) running from the distribution system water main to a meter or building inlet. The valve used to connect a small-diameter service line to a water main is called a corporation stop (also called a tap, or corp stop). One gooseneck joins the corporation stop to the water service pipe work. A second gooseneck links the supply pipeline to a water meter located outside the building. Gooseneck (piping) A gooseneck (or goose neck) is a 180° pipe fitting at the top

neg: Valve pneumatic actuators which are controlled by air pressure, or hydraulic actuators which are controlled by the pressure of a liquid such as oil or water. Actuators can be used for the purposes of automatic control such as in washing machine cycles, remote control such as the use of a centralised control room, or because manual control is too difficult such as when the valve is very large. Pneumatic actuators and hydraulic actuators need pressurised air or liquid lines to supply the actuator: an inlet line and an outlet line. Pilot valves are valves which are used to control other valves.

neg: Sleeve valve (water) Sleeve valve (water) A sleeve valve is a device typically used in a water supply or distribution system when there is a need to reduce high pressure or throttle flow. The sleeve valve consists of a cylindrical gate (tube) which slides over an inner sleeve. The inner sleeve consists of a series of nozzles specifically sized and arranged to provide a solution to cavitation issues frequently encountered in throttling applications with other valve types. Because of its design, it minimizes cavitation. Cavitation that does occur in severe throttling conditions is directed from the valve down to center of the valve

neg: Tap (valve) vacuum breaker or backflow preventer, so that water cannot return through the bibcock from the hose. This prevents contamination of the building or public water system should there be a pressure drop. In the UK, water regulations require a double check valve; this is often incorporated within the body of the tap itself. The American Society of Mechanical Engineers (ASME) publishes several Standards on plumbing. Some are: Tap (valve) A tap (also spigot or faucet: see usage variations) is a valve controlling the release of a liquid or gas. Water for baths, sinks and basins can be provided by separate

neg: Thermostatic radiator valve Thermostatic radiator valve A thermostatic radiator valve (TRV) is a self-regulating valve fitted to hot water heating system radiator, to control the temperature of a room by changing the flow of hot water to the radiator. The classic thermostatic radiator valve contains a plug, typically made of wax (forming a wax motor), which expands or contracts with the surrounding temperature. This plug is connected to a pin which in turn is connected to a valve. The valve gradually closes as the temperature of the surrounding area increases, limiting the amount of hot water entering the radiator. This allows a maximum

neg: Saddle (landform) geology, a saddle is a depression located along the axial trend of an anticline. A 'saddle point' in mathematics derives its name from the fact that the prototypical example in two dimensions is a surface that "curves up" in one direction, and "curves down" in a different direction, resembling a riding saddle or a mountain pass between two peaks forming a landform saddle. Saddle (landform) The saddle between two hills (or mountains) is the region surrounding the highest point of the lowest point on the line tracing the drainage divide (the col) connecting the peaks. When, and if, the saddle

neg: Kingston valve The valve allows sea water to enter the tank. For fuel tanks, the purpose was cleaning the tanks. On water tanks, the Kingston valve gave ship engineers the ability to blow out increasingly salty water from the system, by safely and easily operating the valve from the interior of the ship. Sea water was used in the ship's steam-powered propulsion system, with water being injected and ejected from the boilers. Water, controlled by a Kingston valve, could be deliberately taken on board to act as ballast below the waterline. This provided additional stability and maneuvering. Some shipboard safety systems may

neg: Henry Pratt Co the Henry Pratt Company and then transferred ownership in 1999 to a private investment group headed by Credit Suisse. From 1999 to 2003, Pratt acquired the Ardillo Corporation, assets of Lindsey Fabricators, Inc., Virginia Valve, CCNE, Inc., Hydro Gate Corporation, Milliken Valve Company and Jingmen Pratt Valve, Co., Ltd. The Henry Pratt Company is a subsidiary of the Mueller Water Products Company. Henry Pratt Co added plunger valves to their product line in 2011, and air valves in 2012. The tradition of heavy investment in research and development continues at the Henry Pratt Company. As a result, Pratt holds numerous

neg: Snorkeling when surfacing. Clearing splash water while at the surface requires blast clearing. Some snorkels have a sump at the lowest point to allow a small volume of water to remain in the snorkel without being inhaled when the snorkeler breathes. Some also have a non-return valve in the sump, to drain water in the tube when the diver exhales. The water is pushed out through the valve when the tube is blocked by water and the exhalation pressure exceeds the water pressure on the outside of the valve. This is almost exactly the mechanism of blast clearing which does not

neg: Line stopping methods; and the HTP, which is a high temperature, high pressure system that will stop the flow on existing pipes at operating temperatures above what other methods of line stops can safely stop. A single line stop can be used to stop off and abandon a shutdown. Two or more line stops can be used in tandem to isolate and bypass many intersecting lines at once. Fluid in the line is bypassed, leaving a workable dead section to alter, repair, or add a valve while service provided by this line is continued. Services can be performed on pipes from ¾”

neg: Dredge valve a lot of damages. Because of this reason the dredge valve has a lot of water flushing canals in order to keep it clean. Gate valve Dredge valve The dredge valve is a component of a Cutter Suction Dredge or a Trailing Suction Hopper Dredger that is used control the flow of water and sand in the suction and discharge pipes of one of these types of dredgers. There are 3 cases when this vertical valve can block or reduce the mixture flow of water and sand by lowering its gate: The dredge valve’s gate is hydraulically control and it

neg: Flushometer a flush. The diaphragm technology allows the flush valve to open and let water into the bowl. A main cylinder valve operates up and down. A groove in this cylinder allows water from the main supply to flow through when it is in a mid position. The valve is shut off at both its top and bottom positions. A second valve, placed within the main cylinder valve, releases the water in the topmost pressure chamber when the flush lever is activated, sending the main cylinder valve shooting upwards. The topmost pressure chamber slowly refills through its narrow passageway, pushing the

neg: Tap water Tap water Tap water ("running water", "city water", "town water", "municipal water", etc.) is water supplied to a tap (valve). Its uses include drinking, washing, cooking, and the flushing of toilets. Indoor tap water is distributed through "indoor plumbing", which has existed since antiquity but was available to very few people until the second half of the 19th century when it began to spread in popularity in what are now developed countries. Tap water became common in many regions during the 20th century, and is now lacking mainly among people in poverty, especially in developing countries. Tap water is often

neg: Saddle Mountain (Clatsop County, Oregon) flows. South Saddle Mountain Saddle Mountain (Clatsop County, Oregon) Saddle Mountain is the tallest mountain in Clatsop County in the U.S. state of Oregon. Part of the Oregon Coast Range, Saddle Mountain is in Saddle Mountain State Natural Area in the northwest corner of Oregon. The peak is listed on Oregon’s Register of Natural Heritage Resources. Saddle Mountain was created around 15 million years ago in the Miocene epoch when lava flows poured down the old Columbia River valley. When the lava encountered the water at the Astoria Sea, great steam explosions and thermal shocks occurred to create a large

neg: Larner–Johnson valve 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 New York City. The valve is housed within a bulged section of the penstock pipe. The valve mechanism forms a cylindrical body within this pipe, with the water flowing around it. This downstream section of this valve body is conical and free to move axially. When it moves downstream, it seals against a conical surface at the outlet of the valve, closing off the flow. When closed, the valve is held shut by the

neg: Fire sprinkler system pressure below the water supply pressure. To prevent the larger water supply pressure from prematurely forcing water into the piping, the design of the dry pipe valve (a specialized type of check valve) results in a greater force on top of the check valve clapper by the use of a larger valve clapper area exposed to the piping air pressure, as compared to the higher water pressure but smaller clapper surface area. When one or more of the automatic sprinkler heads is triggered, it opens allowing the air in the piping to vent from that sprinkler. Each sprinkler operates independently,

neg: Building automation is software relying on digital sensors and algorithms to discover appliance or other loads from electrical or magnetic characteristics of the circuit. It is however detecting the event by an analog means. These are extremely cost-effective in operation and useful not only for identification but to detect start-up transients, line or equipment faults, etc. Analog outputs control the speed or position of a device, such as a variable frequency drive, an I-P (current to pneumatics) transducer, or a valve or damper actuator. An example is a hot water valve opening up 25% to maintain a setpoint. Another example is a

neg: Vacuum breaker Vacuum breaker A vacuum breaker is an attachment commonly placed on a bibcock valve or toilet or urinal flush valve, that prevents water from being siphoned backward into the public drinking water system. This prevents contamination should the public drinking water system's pressure drop. A vacuum breaker typically contains a plastic disc that is pressed forward by water supply pressure, and covers small vent holes. Should the supply pressure drop, the disc springs back opening the vent holes (which let in outside air), and preventing backflow of water. A more complex valve that accomplishes much the same purpose is the

neg: Programmable logic controller contacts are both closed, and a true (logic 1) value is passed to the Fill Valve output. Water begins to fill the tank. The internal "Fill Valve" contact latches the circuit so that even when the "Low Level" contact opens (as the water passes the lower switch), the fill valve remains on. Since the High Level is also normally closed, water continues to flow as the water level remains between the two switch levels. Once the water level rises enough so that the "High Level" switch is off (opened), the PLC will shut the inlet to stop the water from

neg: London Underground tube-gauge steam locomotives was built with tunnels of only diameter, but they were enlarged between 1923 and 1925, when the line amalgamated with the Charing Cross, Euston and Hampstead Railway. At the same time, the line was extended southwards to Morden, and the railway bought an 0-4-2 saddle tank from Kerr, Stuart and Company in 1922, to assist with the equipping of the extension. The machine weighed 14 tons, the saddle tank held of water, and 0.75 tons of coal could be carried. The driving wheels were in diameter, and it was considerably less powerful than the Central London machines, generating a tractive

neg: Thermostatic mixing valve Thermostatic mixing valve A thermostatic mixing valve (TMV) is a valve that blends hot water with cold water to ensure constant, safe shower and bath outlet temperatures, preventing scalding. The storage of water at high temperature removes one possible breeding ground for Legionella; the use of a thermostat, rather than a static mixing valve, provides increased safety against scalding, and increased user comfort, because the hot-water temperature remains constant. Many TMVs use a wax thermostat for regulation. They also shut off rapidly in the event of a hot or cold supply failure to prevent scalding or thermal shock. It is

neg: Artificial heart valve the occluder and the valve housing causing a low pressure formation. Water hammer is cavitation caused by the sudden stop of the valve occluder as it contacts the valve housing. This sudden retardation of the fluid retrograde inertia is said to put the fluid under tension causing cavitation. Squeeze flow is said to form a cloud of bubbles at the circumferential lip of the occluder whereas water hammer is said to be seen as transient bubbles at the occlude housing. For either event, cavitation occurs on the upstream side of valve. Clinically, cavitation is of primary concern in the mitral

neg: Flush toilet seat if someone attempts to squat on the edges. In India, the "Anglo-Indian" design allows the same toilet to be used in the sitting or the squatting position. The valve closet has a valve or flap at the exit of the bowl, often with a watertight seal to retain a pool of water in the pan. When the toilet is flushed, the valve is opened and the water in the pan flows rapidly out of the bowl into the drains, carrying the waste with it. The earliest type of toilet, the valve closet is now rarely used for water-flush toilet

neg: History of the steam engine he ran cold water over the reservoir. Operation required several valves; when the reservoir was empty at the start of a cycle a valve was opened to admit steam. The valve was closed to seal the reservoir and the cooling water valve turned on to condense the steam and create a partial vacuum. A supply valve was opened, pulling water upward into the reservoir, and the typical engine could pull water up to 20 feet. This was closed and the steam valve reopened, building pressure over the water and pumping it upward, as in the Worcester design. The cycle essentially

neg: Monkey saddle local minimum or maximum depending on the intersecting plane used. The monkey saddle has just a point of inflection. To see this, consider a line . Along this direction the surface becomes simply , lacking any critical points. Monkey saddle In mathematics, the monkey saddle is the surface defined by the equation It belongs to the class of saddle surfaces, and its name derives from the observation that a saddle for a monkey would require three depressions: two for the legs and one for the tail. The point (0,0,0) on the monkey saddle corresponds to a degenerate critical point of

neg: CGR 1st Class 2-6-0 1876 Kitson was reduced by supplying jets of water, fed from diameter pipes, to the leading wheels while rounding curves. This was found to diminish friction significantly. The cylinders and slide valve faces were lubricated by tallow cups, attached to the sides of the cylinder assembly. When melted tallow was later found to be unsatisfactory, it was replaced by vegetable oils. The eight locomotives were eventually all rebuilt for use in shunting service by relieving them of their tenders and equipping them with saddle-tanks. This was probably done while they were gradually getting withdrawn from mainline work. The main picture shows no.

neg: Saddle Mountain (Clatsop County, Oregon) Saddle Mountain (Clatsop County, Oregon) Saddle Mountain is the tallest mountain in Clatsop County in the U.S. state of Oregon. Part of the Oregon Coast Range, Saddle Mountain is in Saddle Mountain State Natural Area in the northwest corner of Oregon. The peak is listed on Oregon’s Register of Natural Heritage Resources. Saddle Mountain was created around 15 million years ago in the Miocene epoch when lava flows poured down the old Columbia River valley. When the lava encountered the water at the Astoria Sea, great steam explosions and thermal shocks occurred to create a large pile of basalt rocks.

neg: Vauclain compound of the superheater further increased efficiency and made it much easier to maintain. All of the compounding machinery was contained in the valve chest, which in American locomotives (in the days before one piece cast frames) was integral with the smokebox saddle. The whole unit therefore could be unbolted and replaced with conventional single expansion cylinders. That was the typical fate of Vauclain compounds: when the time came for a major overhaul, the compound machinery and Stephenson valve gear were removed, and the engine was rebuilt with superheating, Walschaerts valve gear, and conventional cylinders. Ironically, two of the four surviving

neg: Automatic bleeding valve Automatic bleeding valve An automatic bleeding valve or air release valve (ARV) is a plumbing valve used to automatically release trapped air from a heating system. Air, or other gas, may collect within plumbing. For water delivery systems to taps and basins, this air is flushed through with the water flow and does not cause a problem. In a closed heating system though, it has no other means of escape and builds up. An air bubble trapped within a radiator means that no hot water circulates in the upper part and so the heating power of the radiator is reduced.

neg: Saddle (landform) Saddle (landform) The saddle between two hills (or mountains) is the region surrounding the highest point of the lowest point on the line tracing the drainage divide (the col) connecting the peaks. When, and if, the saddle is navigable, even if only on foot, the saddle of a (optimal) pass between the two massifs, is the area generally found around the lowest route on which one could pass between the two summits, which includes that point which is a mathematically when graphed a relative high along one axis, and a relative low in the , simultaneously; that point being by

neg: PPR 26 Tonner 0-6-0ST 21 May 1899. The first locomotives of the PPR were three saddle-tank engines which were built by Hawthorn, Leslie and Company, one in 1896 and the other two in 1897. They were employed as construction locomotives while the line was being built and were not classified or numbered, but named "Pretoria", "Pietersburg" and "Nylstroom". The engine's cylinders were inclined and arranged outside the thick plate frames. The steam chests were arranged between the frames, with the slide valves being actuated by Stephenson valve gear through rocker shafts. As a result of the outbreak of the Second Boer War in 1899

neg: Sleeve valve (water) in the system. As the orifice holes are relatively small, it is possible and likely that any trash in system will collect in front of sleeve or even in the nozzles themselves. Access ports are generally provided to access the valve interior for debris removal. Typical installations for sleeve valves include the following: reservoir discharge, pump control, pressure regulation, turbine bypass, and tank level control. Sleeve valve (water) A sleeve valve is a device typically used in a water supply or distribution system when there is a need to reduce high pressure or throttle flow. The sleeve valve consists of

neg: Chemigation valve 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

neg: Namaqualand 0-4-2IST Caledonia but in 1871 the first steam locomotives named "John King" and "Miner" were acquired by the mining company. They were followed between 1886 and 1888 by three condensing locomotives and between 1890 and 1901 by seven Clara Class and Scotia Class Mountain type tender locomotives. In 1904, a single 0-4-2 inverted saddle-tank locomotive named "Caledonia" was acquired from Dick, Kerr & Company of Kilmarnock in Scotland. On a saddle-tank locomotive the water tank is mounted astride the locomotive's boiler, while on the much less common inverted saddle-tank locomotive, the boiler is nested in the water tank. The locomotive was an

neg: Saddle crack, particularly if subjected to repeated wet-dry stresses. In a humid climate, excess water for cleaning creates an environment for rot and mold. Once a saddle is clean, a conditioner is used to restore moisture removed by the cleaning process. While glycerine-based saddle soaps have conditioning properties, it is usually important to remove most soap residue before conditioning to prevent product buildup on the leather. Saddles kept in storage also benefit from occasional conditioning to restore natural oils. While conditioning a saddle is an important element of saddle care, and critical in dry climates, over-oiling may rot jute or other

neg: High-density solids pump over large distances, one possible approach is the hybrid feed system. Here compressed air is injected into the delivery line. It presses the plug of material into the pipe. As the compressed air expands the material being conveyed is loosened and separated. As distance increases from the air injection point, what was initially a series of plugs gradually turns into a continuous airborne stream. The amount of air required and the appropriate pipe diameter depend on the type and quantity of matter being conveyed. The said type of gate valve is having a rotating member inside a rotating valve chamber

neg: Oil content meter will be checked by crew members. An OCM is a small part of what is called the oil discharge monitoring and control system. The first part is the oil content meter. The second is a flow meter which measures the flow rate of the water at the discharge pipe. Third, is a computing unit which calculates how much oil has actually been discharged along with the day and time of the discharge. And lastly is the overboard valve control system which is essentially just a valve that can stop the discharge from flowing out at the appropriate time. Oil content

neg: Saddle (landform) ""low point or col on a ridge between two summits"", whilst the Oxford Dictionary of English implies that a col is the lowest point on the saddle. Monkhouse describes a saddle as a ""broad, flat col in a ridge between two mountain summits." The term col tends to be associated more with mountain, rather than hill, ranges. The height of a summit above its highest saddle (called the key saddle) is effectively a measure of a hill's prominence, an important measure of the independence of its summit. Saddles lie on the line of the watershed between two hills. In structural

neg: GWR 3800 Class valves and smokebox saddle, was constructed from two castings from the same pattern, bolted back to back, each casting containing one half of the saddle. The cab, boiler and coupled wheels were attached to plate frames. The cylinder block was carried on two bar frames, bolted to the front end of the plate frames. The piston valves were driven by Stephenson valve gear. The class were fitted with the Standard No. 4 boiler. One locomotive, no. 3805 "County Kerry" was fitted with a smaller Standard No. 2 boiler between November 1907 and May 1909. They were the last new GWR

neg: Valve Pilot valves in the actuator lines control the supply of air or liquid going to the actuators. The fill valve in a toilet water tank is a liquid level-actuated valve. When a high water level is reached, a mechanism shuts the valve which fills the tank. In some valve designs, the pressure of the flow fluid itself or pressure difference of the flow fluid between the ports automatically controls flow through the valve. Valves are typically rated for maximum temperature and pressure by the manufacturer. The wetted materials in a valve are usually identified also. Some valves rated at very

neg: Nokia water supply contamination deliveries were started. There was a poorly designed installation in the Kullaanvuori water treatment facility. A drinking water pipe was connected to a wastewater pipe for the purpose of flushing the wastewater pipe. Such an installation is illegal, and for good reason; if the water pressure in the drinking water pipe is too low, backflow occurs. This is what happened in this event. A maintenance worker accidentally opened the valve, and wastewater flowed into the drinking water supply for two days. The contamination was actually detected, but the company decided to ignore it, assuming it was a transient pulse caused

neg: Check valve lower onto its seat, shutting the valve to stop reverse flow. An in-line check valve is a check valve similar to the lift check valve. However, this valve generally has a spring that will 'lift' when there is pressure on the upstream side of the valve. The pressure needed on the upstream side of the valve to overcome the spring tension is called the 'cracking pressure'. When the pressure going through the valve goes below the cracking pressure, the spring will close the valve to prevent back-flow in the process. A duckbill valve is a check valve in which flow