Hoefer FH225V - Manual (Page 9)

1. Filter Manifold function
and description
The FH225V Ten-Place Filter Manifold and
collection box are designed for filtration of up
to 10 samples simultaneously through 25 mm
filters. The filtration assembly consists of a ten-
place filter support manifold with individual
filter shut-off valves and vacuum gauge, a filtrate
collection box/vacuum reservoir and 10 stain-
less steel chimney weights, which serve as both
sample funnels and filter clamps.
A filter placed on a recessed grid is held in place
by a chimney weight. A thin ridge on the bottom
of the chimney weight compresses the edge of
the filter to create a liquidtight seal, which allows
the chimney of the weight to be filled with up to
13 ml of sample liquid. The vacuum to each filter
position is controlled by a Teflon
® valve. If the
filtrate is to be discarded, it is allowed to drain
directly into the filtrate collection box. With the
optional FH240 rack (ordered separately), indi-
vidual filtrates can be collected into test tubes or
27 mm scintillation vials.
The appropriate vacuum source will depend
on the type of filter and samples used. For best
results with membrane-type filters (nitrocel-
lulose, nylon, PVDF with pore sizes <5 µm), a
vacuum pump is recommended.
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