What is "siphon"

Siphon \Si"phon\, v. t. (Chem.) To convey, or draw off, by means of a siphon, as a liquid from one vessel to another at a lower level.

Siphon \Si"phon\, n. [F. siphon, L. sipho, -onis, fr. Gr. ??? a siphon, tube, pipe.]

1. A device, consisting of a pipe or tube bent so as to form two branches or legs of unequal length, by which a liquid can be transferred to a lower level, as from one vessel to another, over an intermediate elevation, by the action of the pressure of the atmosphere in forcing the liquid up the shorter branch of the pipe immersed in it, while the continued excess of weight of the liquid in the longer branch (when once filled) causes a continuous flow. The flow takes place only when the discharging extremity of the pipe ia lower than the higher liquid surface, and when no part of the pipe is higher above the surface than the same liquid will rise by atmospheric pressure; that is, about 33 feet for water, and 30 inches for mercury, near the sea level.

2. (Zo["o]l.)

   1. One of the tubes or folds of the mantle border of a bivalve or gastropod mollusk by which water is conducted into the gill cavity. See Illust. under Mya, and Lamellibranchiata.

   2. The anterior prolongation of the margin of any gastropod shell for the protection of the soft siphon.

   3. The tubular organ through which water is ejected from the gill cavity of a cephaloid. It serves as a locomotive organ, by guiding and confining the jet of water. Called also siphuncle. See Illust. under Loligo, and Dibranchiata.

   4. The siphuncle of a cephalopod shell.

   5. The sucking proboscis of certain parasitic insects and crustaceans.

   6. A sproutlike prolongation in front of the mouth of many gephyreans.

   7. A tubular organ connected both with the esophagus and the intestine of certain sea urchins and annelids.

3. A siphon bottle.

   Inverted siphon, a tube bent like a siphon, but having the branches turned upward; specifically (Hydraulic Engineering), a pipe for conducting water beneath a depressed place, as from one hill to another across an intervening valley, following the depression of the ground.

   Siphon barometer. See under Barometer.

   Siphon bottle, a bottle for holding a["e]rated water, which is driven out through a bent tube in the neck by the gas within the bottle when a valve in the tube is opened; -- called also gazogene, and siphoid.

   Siphon condenser, a condenser for a steam engine, in which the vacuum is maintained by the downward flow of water through a vertical pipe of great height.

   Siphon cup, a cup with a siphon attached for carrying off any liquid in it; specifically (Mach.), an oil cup in which oil is carried over the edge of a tube in a cotton wick, and so reaches the surface to be lubricated.

   Siphon gauge. See under Gauge.

   Siphon pump, a jet pump. See under Jet, n.

late 14c., from Latin sipho (genitive siphonis) "a siphon," from Greek siphon "pipe, tube for drawing wine from a cask," of unknown origin. Related: Siphonal.

1859, from siphon (n.). Figurative sense of "to draw off, divert" is recorded from 1940. Related: Siphoned; siphoning.

n. 1 A bent pipe or tube with one end lower than the other, in which hydrostatic pressure exerted due to the force of gravity moves liquid from one reservoir to another. 2 a soda siphon 3 (context biology English) a tubelike organ found in animals or elongated cell found in plants. vb. (context transitive English) to transfer (liquid) by means of a siphon.

n. a tube running from the liquid in a vessel to a lower level outside the vessel so that atmospheric pressure forces the liquid through the tube [syn: syphon]

1. v. convey, draw off, or empty by or as if by a siphon [syn: syphon, siphon off]

2. move a liquid from one container into another by means of a siphon or a siphoning action; "siphon gas into the tank"

The word siphon (from "pipe, tube", also called syphon) is used to refer to a wide variety of devices that involve the flow of liquids through tubes. But in a narrower sense, the word refers particularly to a tube in an inverted 'U' shape, which causes a liquid to flow upward, above the surface of a reservoir, with no pump, but powered by the fall of the liquid as it flows down the tube under the pull of gravity, then discharging at a level lower than the surface of the reservoir it came from.

There are two leading theories about how siphons cause liquid to flow uphill, against gravity, without being pumped, and powered only by gravity. The traditional theory for centuries was that gravity pulling the liquid down on the exit side of the siphon, resulted in reduced pressure at the top of the siphon. Then atmospheric pressure was able to push the liquid from the upper reservoir, up into the reduced pressure at the top of the siphon, like in a barometer or drinking straw, and then over. However, it has been demonstrated that siphons can operate in a vacuum and to heights exceeding the barometric height of the liquid. Consequently, the cohesion tension theory of siphon operation has been advocated, where the liquid is pulled over the siphon in a way similar to the chain model. It need not be one theory or the other that is correct, but rather both theories may be correct in different circumstances of ambient pressure. The atmospheric pressure with gravity theory obviously cannot explain siphons in vacuum, where there is no significant atmospheric pressure. But the cohesion tension with gravity theory cannot explain CO2 gas siphons, siphons working despite bubbles, and the flying droplet siphon, where gases do not exert significant pulling forces, and liquids not in contact cannot exert a cohesive tension force.

All known published theories in modern times recognize Bernoulli's equation as a decent approximation to idealized, friction-free siphon operation.

A siphon is a tube in an inverted U shape which causes a liquid, under the pull of gravity, to flow upwards and then downwards to discharge at a lower level.

Siphon may also refer to:

• Soda siphon, device used for dispensing carbonated water
• Siphon (insect anatomy)
• Siphon (mollusc), an organ of many aquatic molluscs through which water (or air) flows
• Oral siphon of Urochordata
• Carotid siphon, a portion of the human internal carotid artery running through the cavernous sinus
• Siphon (cave), a passage in a cave that is submerged under water

A siphon is an anatomical structure which is part of the body of aquatic molluscs in three classes: Gastropoda, Bivalvia and Cephalopoda (members of these classes include saltwater and freshwater snails, clams, octopus, squid and relatives).

Siphons in molluscs are tube-like structures in which water flows (or more rarely in which air flows). The water flow is used for one or more purposes such as locomotion, feeding, respiration, and reproduction. The siphon is part of the mantle of the mollusc, and the water flow is directed to (or from) the mantle cavity.

A single siphon occurs in some gastropods. In those bivalves which have siphons, the siphons are paired. In cephalopods, there is a single siphon or funnel which is known as a hyponome.

A siphon is a tubular organ of the respiratory system of some insects that spend a significant amount of their time underwater, that serves as a breathing tube.

The larvae of several kinds of insects, including mosquitoes, tabanid flies, and Belostomatidae) live in the water and breathe through a siphon.

Some adult insects which spend considerable time underwater have an abdominal breathing tube. For example adult water scorpions have the caudal process which consists of a pair of half-tubes capable of being locked together to form a siphon by means of which air is conducted to the tracheae at the apex of the abdomen when the tip of the tube is thrust above the surface of the water. In immature forms the siphon is undeveloped and breathing takes place through six pairs of abdominal sperms.