What is a Siphon?
A siphon is a tube which can be used to move water from a reservoir to another point. Siphons are capable of raising water over a barrier, which is what makes them distinctive and interesting, as well as highly useful. People have been working with siphons for thousands of years, with evidence suggesting that several ancient cultures were familiar with the basic principle of the siphon, and siphons continue to be quite useful for a wide variety of applications. In classical use, a siphon is a flexible tube which is bent into a u-shape, although a rigid pipe can be used as well. One end of the siphon is inserted into a reservoir, and the other end is inserted into a container to catch the liquid, or left hanging, depending on what one is attempting to accomplish with the use of a siphon. Once the siphon has been started with a priming pump, it will continue to pull liquid out of the reservoir until it is removed or the reservoir is drained. Priming involves filling the siphon with fluid
Theoretically we could come out of the gasoline tank, go straight up into the air with the hose to a height of almost 34 feet and then down into the container and the gasoline would flow with no trouble. I say theoretically because there is friction in the hose that offers resistance to the flow and that friction has to be considered any time you are trying to calculate the possibility of using a siphon to move liquid. The siphon principle is valid if the liquid flow is free from air and vapors so that the densities of the liquid in the rising and falling pipes are alike. It is this principle that can limit the height of the siphon because the flowing liquid can vaporize if its temperature gets too high or the pressure in the pipe gets too low. As an example: A higher water temperature and low barometric pressure conditions limits the height of siphons in cooling tower, condenser cooling water applications to somewhere between 26 and 28 feet. Now let’s go back to our lake and reservoir
