Safety valve having a rupturable housing

Claim 1

A two fluid valve comprising: a first member formed from a polymer plastic material, said first member having a gas port therein, said first member having a surface for forming sealing engagment with another surface; a second member, said second member formed from a polymer plastic material, said second member having a fluid port therein, said second member having a surface for mating with said surface on said first member to thereby provide a sealing region between said surface on said first member and said surface on said second member, said sealing region having means operable for securing said first member to said second member so that said surface on said first member will separate from said surface on said second member in response to a predetermined pressure in said two fluid valve, said first member and said second member coacting to form a housing when said surface on said first member is in mating engagement with said surface on said second member, said housing defined by said first member and said second member, said housing having a float chamber therein for containing a float member, said first member including a sealing shoulder on said gas port to permit a sealing member to seal off said gas port in said first member in response to the level of a liquid in said chamber; said fluid port in said second member operable for the ingress and egress of fluid into the float chamber in said housing; a float of predetermined volume located in the float chamber, said float comprising a polymer plastic material, said float having a weight which is less than a weight of the volume of liquid displaced by said float but greater than weight of the volume of gas displaced by said float, a gas port sealing member located on said float for sealing said gas port in response to liquid reaching a predetermined level in the float chamber to thereby prevent discharge of fluid through said gas port, said sealing member having a sufficiently short projection so that the tilting of said two fluid valve does not produce misalignment of said sealing member with said gas outlet port; said housing including members for supporting said float in a spaced position from said fluid port to permit ingress and egress of fluid past said float when said float is located on said supporting members whereby said two fluid valve is operable for normally permitting ingress and egress of gas through said gas port when the liquid level in the float chamber is insufficient to force said sealing member on said float into sealing contact with said shoulder on said gas port and for normally not permitting ingress and egress of fluid through said gas port when the liquid level in said float chamber is sufficient to force said sealing member on said float into sealing contact with said shoulder on said gas port; said sealing region securing means between said first member and said second member forming a region of minimum strength so that when said sealing member on said float chamber is in sealing contact with said sealing shoulder on said gas port, said region of minimum strength is operable for rupture at a predetermined pressure level to thereby prevent damage to a system connected thereto should the pressure exceed said predetermined pressure level.