Everything about the suction pump

Pumps can be used to pump liquids or liquids. Depending on the technology and function of a pump, pumps are referred to according to which technology they use or how they promote the fluid. Among the latter pumps also includes the suction pump.

The most commonly used pumps

Pumps are turbomachines: the kinetic energy in a pump is transferred to the fluid to be pumped and thus also put in connection. Most pumps used in everyday environments are one of the two following pumps:

  • submersible pump
  • suction pump


The most noticeable difference between the two pumps is that the submersible pump is completely submerged in the medium to be pumped, whereas the suction pump is located outside and draws in the liquid via a suction tube or a suction hose.

Principle of operation of the suction pump: negative pressure

There are a few physical principles to be observed especially with the suction pump. There is over pressure around us. Suction pumps use the effect of negative pressure. From the point where the negative pressure equalizes the atmospheric pressure, it is no longer a vacuum, but a vacuum.

Suction pumps are vacuum pumps

Therefore, pumps that generate greater negative pressure are also referred to as vacuum pumps. The problem with a vacuum pump is that the vacuum can divide a liquid like water into vapor particles. In addition to the atmospheric pressure, another more accurate finding of the point between vacuum and vacuum is that of the lowest atmospheric pressure that occurs. That corresponds to a pressure of 300 mbar.

As a result, the application is physically limited

In particular, when delivering liquids, the atmospheric pressure is an important factor. The prevailing mean air pressure corresponds to the height of a water column of approximately 10 m. If the maximum possible negative pressure of a pump (before reaching the vacuum) and the height of a water column are set in relation to one another until the same pressure is reached, then the maximum delivery height of a suction pump is 10 m.

Alternatives to suction pumps

However, technical aspects must also be taken into consideration. If these are also removed, suction pumps can suck in a water column at a height of seven to eight meters. If a liquid is conveyed over a longer distance, a suction pump is therefore no longer sufficient.

Then a suction pump must be replaced or supported by pressure pumps. But since pressure pumps always have only a certain maximum delivery head, even more height differences that are to be overcome, quasi stages must be created with individual pressure pumps.

Factors that limit the application possibilities of a suction pump

So whether you can use a suction pump for your project depends on the technical equipment of the pump, the pump efficiency in particular on the height of the water column, which arises. In addition, the outlet of the liquid can also be controlled pressure-dependent. So there are several factors that directly influence the possibilities of a suction pump:

  • Head or height of the water column
  • Power of the suction pump depending on the intake manifold diameter
  • any overpressure arising or to be applied on the outlet side

Typical applications for suction pumps

There are numerous applications in which a suction pump can be used. For example, when pumping off petrol or pumping it over with fuel oil, when draining a drainage system or even the garden fountain pump with manually operated pans.

Tips & Tricks

A typical suction pump is the piston pump.

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