Q. What is vacuum filtration?
A. In its simplest form, vacuum filtration involves “pulling” the
process coolant through a filter membrane, where the chips are caught and
the solution passes through. Technically speaking, vacuum filtration is the
cleaning of a liquid using the suction side of a pump to impart a negative
pressure on the solution to be cleaned.
Q. What is pressure filtration?
A. Pressure filtration involves “pushing” the process
coolant through a filter membrane. In this case, positive pressure
is used to pass the solution through the filter rather than the negative
pressure of vacuum filtration.
Q. Which type of filtration is better, vacuum or pressure?
A. While both types of filters will work for most applications, vacuum
filtration is generally a better choice than pressure filtration.
Vacuum filters provided clean solution at a lower initial price,
with lower operating costs, and are easier and less costly to maintain.
Q. What is filter media?
A. Filter media is the single most important component on the filter.
It is the membrane that catches the chips and other contaminants
as the process solution passes through. The media comes in a roll
mounted on the back of the filter unit.
Q. Why is the filter media and its proper application so important?
A. The filter media determines how clean the filtered solution will
be. Many a good filter application has gone bad as a result of
misapplied media. It is akin to the saying, “You can ruin
a ten-dollar drunk with a one-dollar hamburger.” Factors
such as wet strength, air permeability, and compatibility with
the process coolant must be considered before applying any media.
Q. What is an ejector (a.k.a. “poor man’s pump”),
and why is it important?
A. The ejector is simply a device that removes air from the vacuum
chamber of the filter. It is important because a vacuum cannot exist
in the presence of air, and the effective operation of the filter
is based on the vacuum. Each D.E. Smith, Inc. vacuum filter unit
is equipped with an ejector.
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