Anyone who has ever had to siphon gas out of a car or truck can testify to the value of having a bulb siphon pump. The alternative — using your mouth and lungs to get enough suction to start the gas moving through the siphon hose — is not only distasteful, it can also be dangerous.
Bulb siphon pumps are the ideal way to initiate any type of siphoning procedure, whether it’s getting fuel out of a gas tank, draining liquid chemicals from a barrel, or any other type of liquid transfer. They are safe, effective, and convenient tools to have around any shop or warehouse.
With a bulb siphon, the hand-pumped bulb begins the process of pulling the liquid into the hose so that it can travel up the side of the container before being pulled down into the spillway, whether it’s into a sewer, a bucket, or some other landing place. In other words, the bulb does the work of your mouth and lungs, preventing the liquid from accidentally getting into your mouth.
While a little gasoline probably won’t hurt you, it’s certainly not going to taste very good. But trying the traditional method of siphoning a more caustic liquid such as a high acid or dangerous chemical just isn’t practical.
How Siphon Pumps Work
Interestingly, not all scientists agree on how liquid can be forced to flow uphill by means of a siphon. There are two theories about how it works.
The first is based on hydrodynamics, or the idea that water and other liquids will always seek its own level. Once the liquid has been pulled up and over the side of the tank, barrel, or another container via suction, gravity will pull the liquid down the hose where there is reduced pressure.
Atmospheric pressure pushes the liquid from the upper container into the reduced pressure at the top of the siphon in the same way a straw will pull soda up into your mouth. Then it flows downhill naturally.
The Problem with Siphon Physics
But this theory is undermined by the fact that siphons will work in a vacuum, where there is no atmospheric pressure. They also work at heights higher than the barometric height of the liquid.
Which brings us to the second theory, called cohesion theory, which says the liquid is pulled over the siphon the same way a chain model works. In a chain model, the lower section is heavier than the top section, so it pulls the top section down.
Which theory is correct? Modern science can’t agree. But one that everybody can agree on is that just about every workplace needs to have a bulb siphon pump for when it’s needed.