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Vacuum pump – operating principle |
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Multi-step-vacuum pumps (ejectors)
The physical principle of our ejector vacuum pump can be characterized by both
the Bernoulli-equation and by the Venturi principle. It is
important (this is in fact contrary to what we supposed), that a
flowing fluid has a vacuum relative to its sourroundings. These
physical principles are not only applied for the construction of vacuum
ejectors, but also for the water jet pumps (which are well-known from the
school lessons in chemistry) or for the suction head of a carburettor.
It is typical for one-step ejectors that, depending on the geometry of the nozzles, you
can either get a high end vacuum (with a low suction power) or a high suction power with
a low vacuum level.
Our TIVAtec vacuum pumps have more nozzle steps integrated so that a maximum suction power is
reached with a low energy level and a high end vacuum level.
In comparison to the one-step ejectors resp. Venturi nozzles, with the TIVAtec vacuum pumps,
the energy which remains in the pressure after the first nozzle step, is exploited to a maximum.
Since the following nozzle steps cannot produce such a high vacuum as the first step, they are
equipped with non-return valves which close exactly at the point when the pressure in the area
to be evacuated is lower than in the area of the considered following step. This means that the
non-return valve closes as soon as the pressure in the considered following step is higher
(e.g. 40% vacuum) than the pressure in the area to be evacuated. Then the evacuation is continued
with the remaining nozzle steps.
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