Two Simple Modifications of the Common Type of Metal Filterpump Everyone who teaches undergraduate laboratory courses is familiar with the nuisance and time loss due to poorly functioning filterpumps. The poor functioning of metal filterpumps in laboratories with sufficient water pressure is nearly always due to either solid material blocking the serrated hose connection with cheek valve, or a corroded and sticking check valve. Both causes are the result of carelessness or improper use of the filterpump, but are difficult to prevent in a teaching laboratory. Polypropylene filterpumps can more easily be cleaned than metal ones but have as additional disadvantage that the suction hose connection is not an integral part of the pump and is either lost or is still attached to the suction hose in the locker of the last user! Clueing the hose connection in place makes cleaning of the pump more difficult. The disadvantages of a glass filterpump with integral check valve are high price and hreakahilitv. .. The authors have made two modifications to the common type of metal filterpump, Fisher Air-ejector (A), which make it more reliable in ooeration and much easier and auieker to clean. 1 1 The metal check valve was replaced hy a $,,;-in.diameter Teflon ball.' 21 Around the tapered serrated hose connection a $ - m stainless steel hexagon nut was silver soldered (6). This allows easy and quick rsmovaloirhe thrcnded serrated hose connection with eheek valve. All the lahuratories arc equipped nith a '.>-in drep hexagon v ~ r k r twrench with a ',-in. drive sliding T-bar handle This handle allow.; maximum manruverability. in quickly removing the hose connection in places where the faucet han. dle may interfere. A piece of %-in. diameter (welding) rdd with haidle can be used to push the eheek valve assembly out of the hose connection for further cleaning.
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'Teflon halls #BT-3, diameter %s-in., Small Parts Ine., 6901 NE 3rd Avenue, Miami, Florida 33138.
University of Victoria Victoria, B.C., Canads V8W 2Y2
Karel Hartman William H. Tawner
