FILTERS MADE OF POROUS POLYURETHANE FOAM
Use of Scott industrial foam as a filter media in IBM Corporation's magnetic core information storage units permitted a filter design which met the company's specific air flow requirements.
Polyurethane media, developed by Foam Division, Scott Paper Company, currently is used to clean air circulated through three IBM memory units: the 7302 II -- shown here on IBM production line -- plus the 7107 and 7117 models.
Media was selected because it is dry, easily fabricated, readily cleaned and contains no harmful contaminants, according to IBM.
Scott industrial foam was chosen over fibrous glass and metallic filters which required oil impregnation. Metallic media also tended to chip at edges, creating contamination problems and possible errors in equipment operation.
Sensitive memory units in several IBM data processing systems are protected against airborne contaminants by filters made of porous polyurethane foam.
The filters, supported in anodized aluminum frames, clean the air circulated to cool the memory units for three computer models.
Without a filter, dust and other contaminants would gather between wires and around magnetic cores creating hot spots and causing possible errors in information storage.
Use of the polyurethane media permitted IBM engineers to design filters which met their specific air flow requirements.
The filter media is an ester-type "open-pore" polyurethane foam developed by the Foam Division, Scott Paper Company, and now used in a variety of industrial filtration, demisting and acoustic control applications.
It is 97 per cent air space and has no membranes connecting interior skeletal strands.
These interconnecting strands break the air stream into jets and deposit airborne contaminants inside the media rather than on the surface.
Scott industrial foam was adopted as a filter media by IBM's Development Laboratory, Data Systems Division, Poughkeepsie, N. Y., because it is dry, easily fabricated, readily cleaned and contains no harmful contaminating properties, according to Homer Dorminey, mechanical design manager, Solid State Memory Development.
IBM specified the foam media in preference to fibrous glass and aluminum media.
Because the latter materials required oil impregnation to entrap dust particles, cleaning proved to be a more involved process. In addition, metallic filters tended to chip at the edges releasing damaging particles into the memory unit air stream.
IBM found that correcting this chipping problem could triple the cost of the metal filter.
The polyurethane foam filters are considered permanent and are removed periodically for cleaning either by washing or vacuuming.
They are readily accessible and easily removed.
Frequency of cleaning depends on efficiency of the over-all air conditioning system.
The foam is bonded to the filter frame with an epoxy compound. Anodized aluminum was selected for the support because it is light, strong, easily finished, and has a good long-term appearance.
Further information may be obtained from Foam Division, Scott Paper Company, 1500 E. Second Street, Chester, Pa.
For: Scott Paper
Company Foam Division From: Ketchum, MacLeod & Grove, Inc. Four
Gateway Center - Pittsburgh, Pa. 15222 Al Croft - Phone: 261-5100