Even if it is a small number of particle, when few cracks of a filter are passed,
an outflow etc. will occur and the serious situation will be brought about.
In order to prevent users's labor, waste of time, and loss of a precious product,
YAMASHIN is performing the completeness test for all membrane filters.
The breakage of the membrance filters, the imperfect seal, etc. can be foreknown by this test.
Moreover, if the used filters are got after a filtration end, YAMASHIN will perform the completeness test.
It can be checked that a membrance filter continues being in a perfect state,
and whether the leak has arisen in the filtration process.
I introduce the completeness test, "a bubble point examination", which YAMASHIN is performing.
Moreover, I also introduce other completeness tests, a diffusion examination and a pressure hold test.
The bubble point examination
YAMASHIN perform "the bubble point examination" for all membrane filters.
A membrane filter can be considered to be a thing like a detailed and uniform capillary vessel.
It has the uniform passage penetrated from a primary side to the secondary side.
By the bubble point examination,
We can know the minimum pressure which needs for a liquid to be held on membrane with surface tension
and to be pushed out from membrane, Therefore, the caliber can be measured.
In bubble point examination, it is carried out by checking that the air in a membrane filter passes to the secondary side
When raising the air pressure of the primary side of a membrane filter that be made wet in advance.
The pressure in case the flow of the steady and continuous bubble is seen becomes bubble point pressure.
When the bubble point is remarkably lower than the bubble point that was actually observed and was specified
in the membrane filter,
it is shown whether damage has occurred in membrane or the seal is imperfect.
The membrane filter with a problem examines again, and when a result equivalent to a first examination comes out,
we cancel a membrane filter as a fault article.
The diffusion examination
It is one of the test methods which checks abnormalities, Damage on a membrane filter etc.
It applies the principle that Gas dissolved and diffused into the liquid which wetting the film,
and measures the flux of the gas diffused in the filter's secondary side.
Although a diffusion value changes with filter area, membranous thickness, rate of opening hore, etc.,
there is no direct relation to caliber of the filter.
The pressure hold test
Although it applies the same principle as the diffusion examination,
in the pressure hold test, the drop-in-pressure value of the primary side produced by the dissolution and diffusion
is measured, and the filter's quality is judged.
The value changes with filter area, membranous thickness, rate of opening hore, and the capacity of housing etc.
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