ROBERT LEON THOMPSON, M.D.
Osteopathic Medicine at Hermann Dr, Houston, TX

4793934, Dec 27, 1988

Apr 22, 1987

7/041307

Robert E. Thompson - Houston TX
Kurt M. Geiser - Minneapolis MN

Signal Environmental Systems, Inc. - Hampton NH

C02F 152

210715

A multi-bed filtration system includes an upstream filter bed in series with a downstream filter bed of nonbuoyant media. Also included is a system for periodically backwashing the nonbuoyant filter bed. Coagulant-treated water is passed through the upstream filter bed, followed by the downward flow of water through the downstream filter bed. Thereafter, the downward flow of water through the downstream filter bed is periodically interrupted. During these interruptions, a limited amount of water is introduced upwardly through the downstream filter bed by the backwashing system. Such backwashing frees coagulated solids within the bed, causing the solids to move upwardly through the bed. The solids ultimately collect in a zone above the surface of the bed. When normal filtration recommences, water passes through the deck of solids in the zone prior to entering the nonbuoyant filter bed.

4339897, Jul 20, 1982

Nov 5, 1980

6/204345

Robert E. Thompson - Houston TX
Richard P. McNinney - Richmond TX

Schmidt Manufacturing, Inc. - Houston TX

B24C 700

51436

Sandblasting apparatus and valve apparatus therefor, and methods for performing sandblasting operations, wherein an abrasive-filled pressure vessel is pressured by sandblast air when an air control valve is opened, and wherein automatic blowdown of the pressure within the pressure vessel is required when the air control valve is closed, a dual valve structure being provided in which the air control valve and blowdown control valve are combined and in which the two valves operate in tandem, one valve being open when the other is closed.