Automatic valve assembly
Patent 4917795 Issued on April 17, 1990. Estimated Expiration Date: 
May 18, 2008. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
May 18, 2008. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesInventorsAssigneeApplicationNo. 195603 filed on 05/18/1988US Classes:210/120, Vent control137/202, Float responsive137/614.2, Direct response normally closed valve limits direction of flow137/614.21, Coaxial oppositely directed seats210/123, Controls valve210/169Aquarium or swimming poolExaminersPrimary: Jones, W. GaryAssistant: Lee, Coreen Y. Attorney, Agent or FirmForeign Patent References
International ClassB01D 023/20AbstractAn improved automatic air pressure relief and check valve assembly which may be used in combination with a swimming pool filter tank or a swimming pool separation tank. The valve assembly includes a normally open lower valve which communicates with the inside of the tank and is responsive to the tank's being full of pressurized water for closing the lower valve. The valve assembly further includes a normally closed upper valve communicating with the lower valve and the outside of the tank, the upper valve being responsive to air being expelled from the tank through the open lower valve, when water is filling the tank, for opening the upper valve to permit the air being expelled to exit through the upper valve. Cooperating with the upper and lower valve of the improved valve assembly is means for precluding both the upper and the lower valves from being simultaneously maintained in their closed conditions. Associated with the normally closed upper valve is selectively actuable means responsive to an externally applied force for opening and maintaining open the upper valve while the force is applied during selected times when water is not entering the tank, for permitting air to enter the tank so that water may be drained from the tank when desired.Other References
Field of SearchAquarium or swimming poolCheck valve controlled Float type Responsive to material level Vent control Controls valve Float in receptacle other than that of separator Filter coaxial with valve seat or valve stem Filter surrounds valve Vented Attached variable flow controller Float responsive Tank with gas vent and inlet or outlet With external means for opposing bias Coaxial oppositely directed seats Direct response normally closed valve limits direction of flow Diverse material seal at valve interface Particular head and seat cooperation | |
