Hoefer FH225V - Manual (Page 13)

2. Operating instructions
1
Optional: Install the FH240 rack (ordered separately).
Test tubes: Wrap a rubber band (provided) around
each pair of posts on the rack. Slide the required
number of 13 × 100 mm test tubes into position—
one tube between a pair of posts. Orient the rack so
that the pegs in the filtrate collection box fit through
the rack slots. When in place, the rack should rest
flat against the bottom of the box.
Scintillation vials: Place the required number of scin-
tillation vials into the rack, and then place the rack
oriented so that the pegs support it. (This position is
180° from the position in which the pegs fit through
the rack slots).
2
Place the manifold on the filtrate collection box/
vacuum reservoir. If filtrates will be collected sepa-
rately, check that each filter holder outlet is in a test
tube or scintillation vial.
3
Connect the top hose connector on the filtrate collec-
tion box to a vacuum source. A vacuum pump is
recommended; house vacuum is often insufficient,
especially for membrane filters.
4
Seal the bottom hose connector by installing a short
piece of tubing and clamping it closed. (The lower
connector serves as a drain for filtrate not collected in
test tubes or vials.)
5
Place (wetted) filters on the filter holder grids.
6
Place a chimney weight on each filter. The ridge at
the bottom of each weight fits inside the well edge.
•
p5
Tip: Use a long thin object
such as a pencil to stretch the
rubber band before inserting
the test tube.
Fig 2. Cut-away diagrams
showing rack position for test
tubes (top) and scintillation
vials (bottom).