Polyolefin sealing gasket

Abstract

A semi-rigid polyolefin water heater gasket is employed to increase the speed and reduce the cost of installing a urethane leakage barrier between an inner water heater vessel and an outer shell. The gasket comprises a strip of polyolefin material that is wrapped around the exterior of an inner water vessel in the space between the inner vessel and the outer shell. This gasket provides a leakage barrier secured in this space and prevents liquid urethane from flowing beyond the gasket or gas dam ring. An adhesive can bond the gasket in the gap.

1 . In a water heater having an inner water tank and an outer shell surrounding the inner water tank and defining an annular clearance space between the inner water tank and the outer shell wherein the improvement comprises: an annular gasket formed of extruded polyolefin concentrically disposed between the inner water tank and the outer shell and covering the annular clearance space. 
   
   
       2 . The improvement as claimed in  claim 1  wherein the gasket has a body portion with two free ends and encircles the outside wall of the inner water tank. 
   
   
       3 . The improvement as claimed in  claim 2  wherein the gasket is secured to the outside wall of the inner water tank. 
   
   
       4 . The improvement as claimed in  3  wherein the two free ends are spirally overlapped with respect to each other. 
   
   
       5 . The improvement as claimed in  claim 3  wherein the gasket is secured by an adhesive. 
   
   
       6 . The improvement as claimed in  claim 1  further comprising: means for cutting segments of the extruded polyolefin of a predetermined length as the polyolefin is extruded from the extruding machine. 
   
   
       7 . The improvement as claimed in  claim 5  wherein the extruded polyolefin has a “D” shaped cross section. 
   
   
       8 . The improvement as claimed in  claim 5  wherein the extruded polyolefin has a square cross section. 
   
   
       9 . The improvement as claimed in  claim 2  wherein the extruded polyolefin is polyethylene having a density of between 0.5 and 6.5 pounds and a compressive strength of from 4.5 to 12.5 psi. 
   
   
       10 . The improvement as claimed in  claim 5  wherein the extruded polyolefin is a foam cross section. 
   
   
       11 . The improvement as claimed in  claim 2  wherein the extruded polyolefin is fire retardant. 
   
   
       12 . The improvement as claimed in  claim 6  wherein the extruded polyolefin is fame retardant. 
   
   
       13 . A process for constructing a water heater having an inner water tank and an outer shell which is located in spaced relation to and surrounding the inner water tank so as to define an annular clearance space between the inner water tank and the and the outer shell comprising the steps of: providing the inner water tank; providing the outer shell; placing the outer shell in spaced relation to and around the inner water tank; creating an enclosed annular gasket from a length of extruded polyolefin, positioning the annular gasket around and in contact with the inside wall surface of the outer shell, the gasket having a radial thickness greater than the radial width of the annular space, and moving the outer shell downwardly coaxially over the water tank to compress the annular gasket between the inner water tank and the outer shell. 
   
   
       14 . The process as claimed  13  wherein the cross section of the annular gasket is “D” shaped. 
   
   
       15 . The process as claimed in  claim 13  wherein the cross section of the annular gasket is square.