# siphon

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## siphon

(sī`fən, –fŏn), tube or other enclosed conduit through which a liquid is lifted over an elevation and then emptied at a lower level. The movement of the liquid is driven primarily by the force of gravity. A siphon is typically shaped like an inverted J or U; to operate, it must discharge at a level lower than that of the liquid's surface on the intake side. The siphon must be filled before it will operate; suction is sometimes used initially to draw a liquid into a empty siphon.

## Siphon

a bent tube with legs of different lengths, through which a liquid flows from a vessel at a higher leveito a vessel at a lower level (see Figure 1). In order to start the operation, the siphon must first be filled with the liquid. The action of a siphon results from the fact that the pressure on the liquid volume filling the upper (hatched) section of the siphon applied from the direction of the upper reservoir, that is, from the left, is higher than that applied from the direction of the lower reservoir, that is, from the right. Thus, at the moment when the flow starts, the pressure on the left is equal to p0γh1 and the pressure on the right is equal to p0 - γh2, where γ is the specific weight of the liquid, p0 is the pressure on the free surface of the liquid, and h2 > h1. In this manner, when the liquid is flowing

Figure 1. Diagram of the operation of a siphon

through the siphon, a pressure is established in the upper section that is lower than p0. The greater the difference in the heights h2 - h1 and the greater the liquid’s energy loss in overcoming the resistance of the tube, the greater the pressure drop in the upper section. This circumstance limits the difference in the heights of the liquid and, consequently, the operation of the siphon; when the pressure in the flow is below a certain limit, the column of liquid is disrupted. When cold water at atmospheric pressure is being transferred by a siphon, the maximum difference in the heights is usually no more than 6 to 7 m.

## siphon

[′sī·fən]
(botany)
A tubular element in various algae.
(engineering)
A tube, pipe, or hose through which a liquid can be moved from a higher to a lower level by atmospheric pressure forcing it up the shorter leg while the weight of the liquid in the longer leg causes continuous downward flow.
(geology)
A passage in a cave system that connects with a water trap.
(invertebrate zoology)
A tubular structure for intake or output of water in bivalves and other mollusks.
The sucking-type of proboscis in many arthropods.

## siphon

, syphon
1. a tube placed with one end at a certain level in a vessel of liquid and the other end outside the vessel below this level, so that atmospheric pressure forces the liquid through the tube and out of the vessel
2. See soda siphon
3. Zoology any of various tubular organs in different aquatic animals, such as molluscs and elasmobranch fishes, through which a fluid, esp water, passes
References in periodicals archive ?
Najib has since bought his own water pump and has also begun siphoning water away from his neighbors.
An illegal siphoning conviction in Mexico carries a maximum sentence of 10 years and a \$43,000 fine, Panes and Dyer said, however, a group of Senators are considering raising the sentence to 35 years by classifying siphoning as an organised crime.
Mr Forbes was using a length of rubber tubing to start the siphoning process, before transferring the fluid to smaller containers.
The TankSafe device from Tiss Security Systems fits inside the neck of an HGV fuel tank, allowing fuel to flow in but preventing thieves from siphoning it back out.
While leaks remain a major problem, an equally important defect is the siphoning of gasoline from the tank.
Q: Some people who are harshly critical of Saddam Hussein and who take a bellicose stand say that the Oil for Food program wasn't working and that Saddam Hussein was siphoning off the revenues of the oil sales to feed the military, to feed himself, feather his nest.
Cable was siphoning off audience share from FCC-regulated speakers and messing up the entire FCC plan.
After two 10-minute cycles, the same process is repeated, but with five-minute settling periods before siphoning and refilling.
Because the industrial defense sector is also expanding, there has been concern that these programs might be siphoning off most of the nation's best young engineers, and setting up the civilian sector for a serious shortfall of available engineering graduates -- a factor that could affect U.

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