Fluid control and shut off valve
Patent 5100100 Issued on March 31, 1992. Estimated Expiration Date: 
September 12, 2010. 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.
September 12, 2010. 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 References 3614486 3851526 Thermal mass flowmetering Fast responsive flowmeter transducer Fluid control device Mass flow controller Patent #: 4977916 InventorsApplicationNo. 581640 filed on 09/12/1990US Classes:251/129.06, Having element dimensionally responsive to field137/486Responsive to change in rate of fluid flowExaminersPrimary: Cohan, AlanAttorney, Agent or FirmForeign Patent References
International ClassesF16K 031/02G05D 007/06 AbstractAn improved control and shut off valve assembly is disclosed. The preferred valve assembly provides sufficient forces to overcome biasing forces so as to provide adequate shut off at a leakage rate of less than 10-9 std cc/sec of He with an atmospheric differential of Helium applied across the valve seat of the assembly, and precise control of the flow rate, all as a function of a single electrical control signal. In accordance with another aspect the valve seat is made from a material softer than the valve seat engagement means so that the seat is coined by the valve seat engagement means when first used so as to insure tight tolerances for sealing the valve passageway during the shut off mode. Finally, in accordance with yet another aspect of the invention, the valve assembly is constructed with no separate parts within the flow path so as to maintain a clean passageway. | |
