The present invention relates to an improved vacuum breaker valve and method of assembly. In the prior art, vacuum breaker valves are known from U.S. Pat. Nos. 4,232,706, 4,440,406, 4,535,807 and 4,991,623. U.S. Pat. No. 4,440,406, discloses devices used for the connection of pipes. No valve structure or method of assembly are disclosed in this patent and, as such, this patent is believed to be of only general interest concerning the teachings of the present invention. However, the other above-listed United States Patents to applicant herein all disclose vacuum breaker valves intended for use in the same environment as disclosed herein.
Of these three patents, U.S. Pat. No. 4,232,706, discloses a valve head having an annular shape of generally triangular cross-section designed to seat on a valve seat consisting of two concentric annuli. This patent fails to disclose any guide means either associated with or connected to the valve head. U.S. Pat. No. 4,991,623, discloses a valve head seating on a valve seat consisting of two concentric annuli. The valve head has a plurality of circumferentially spaced radially outwardly extending lugs slidably received within respective grooves formed within the interior of the cover to guide the valve in vertical movements. The valve head guide structure of this patent is an integral one piece construction.
Finally, U.S. Pat. No. 4,535,807, discloses a valve head described as "a membrane or an annular flap" of undisclosed material and having an annular support attached thereto in a manner undescribed, with the annular support being made "of a plastic material". The plastic support includes guiding lugs having internal grooves designed to cooperate with externally extending ribs molded onto the outside of the valve body. A problem has arisen in the interconnection of the annular flap and annular support in that they are difficult to assemble. In practice, the annular flap and annular support have been interconnected through the use of a suitable adhesive. However, in the humid, corrosive environment of a vacuum breaker valve, this means of interconnection has occasionally proven ineffective and, the annular flap and annular support have separated eliminating the guidance feature of the annular support. This could cause the annular flap to become misaligned with respect to the valve seat much in the manner which may occur with regard to the valve disclosed in prior U.S. Pat. No. 4,232,706. As such, a need has developed for a more effective manner of interconnection between the annular valve flap and the associated annular support. It is the solution to this problem which is the basis for the present patent application.
In addition to the prior United States Patents, above-listed and discussed, applicant is aware of the following prior art U.S. Pat. Nos.:
2,872,938 to Hansen et al. PA0 2,928,413 to Hansen et al. PA0 4,556,084 to Frawley PA0 4,643,221 to Parker PA0 4,861,462 to Lehmann et al. PA0 4,886,085 to Miller.
While each of these patents teaches a valve which is opened responsive to sensing of conditions in the flow line such as reduction of pressure on one side of the valve, none of these references teaches a valve wherein the valve head includes a valving plate connected to a valve guide through the provision of a melting and fusing process.