Gelman Sciences, Inc.

Robert E Corbett

Monty E Vincent

Attila Vadnay

Charles E vonReis

The filter device has a housing with elongated top and bottom walls and side walls which taper inwardly from top to bottom. The top wall has extending downwardly therefrom into the housing a generally flat filter membrane support with a quadrangular periphery, a pair of filter membranes being disposed on opposite sides of the support and sealingly bonded to its periphery, the support having a center portion with spaced coplanar surfaces on each side to provide support for the center portion of the filter membranes. The housing is provided with an opening communicating with the space between the two filter membranes and with an opening communicating with the space between the housing and the two membranes. The bottom wall and side walls of the housing are in the form of a unitary molding of organic polymeric material open at its upper end, and the top wall and the downwardly extending filter membrane support is formed of another molding of organic polymeric material bonded about the periphery of the top wall into the open end of the outer molding. Because of such structure the device can be manufactured at relatively low cost and is compact while yet affording a large filtering area.

Filter device

The disposable filter device of the invention is particularly suited for testing for the amounts of tars and nicotine in cigarettes and comprises a housing having two components (2,4) one of which has a cylindrical portion (8) and the other of which has an annular flange (48) whereby the two members can be telescoped together with a filter disc (6) therebetween for collecting the tars and nicotine. The member with the cylindrical portion is formed of a relatively soft resilient substantially non-hygroscopic polymer and the member with the annular flange is formed of a relatively hard substantially non-hygroscopic polymer. The resiliency of the member with the cylindrical portion in combination with the relative hardnesses of the members and the particular shapes of the telescoped portions (12,48) enables the two members to be removably secured together with an excellent seal therebetween. Because both members are of substantially non-hygroscopic polymers, the device is substantially free of moisture absorption and hence free of inaccuracies, due to moisture absorption, in determining the amounts of tar and nicotine collected.

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Ann Arbor, MI, United States of America

Robert E Corbett