Apparatus for and method of freeze protecting plumbing
Patent 4286613 Issued on September 1, 1981. Estimated Expiration Date: 
January 16, 2000. 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.
January 16, 2000. 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 1268648 1338469 1554344 1558276 1786878 3320965 3369556 3397711 3618625 Water cock with non-freezing valve Patent #: 4066090 InventorApplicationNo. 06/112485 filed on 01/16/1980US Classes:137/62, Low temperature responsive drains137/317, Tapping a pipe, keg, or apertured tank under pressure137/79, Temperature138/34, Anti-freeze substance138/35, Portable thawing apparatus237/80ANTIFREEZING DEVICESExaminersPrimary: Rosenthal, ArnoldAssistant: Walton, G. L. Attorney, Agent or FirmInternational ClassesE03B 7/00 (20060101)E03B 7/10 (20060101) AbstractA gate valve, mounted in a drain pipe connected to a downstream exposed end of a part of a plumbing system subject to occasional freezing, is controlled to open and close by opposed pressures of a spring and a temperature controlled pressure of a refrigerant fluid in an expansible and contractable bellows, the respective pressures being equalized at 33 degrees F. with gate valve closed, the pressure differentials therebetween resulting from temperature changes progressively opening and closing valve at temperatures below 33 degrees F. and closing it and keeping it closed at 33 degrees F. and above, and thereby preventing the plumbing from freezing, by allowing water to flow therethrough at and below freezing. | |
