Patent ID: 8919367

Claim:
A method for preventing the backflow of gases from being drawn up through a drain line having a drain wall defining a drain line inner radius, the method using a gas impermeable but water soluble device having a substantially circular body and a plurality of flanges, the body having a periphery defining a body radius, each flange projecting radially outward from the periphery and being attached to the body along a bend line, each flange defining a flange radius exceeding the drain line inner radius, the method may comprising the steps of: (a) inserting the device into the drain line so that the periphery is in close proximity to the drain wall and the flanges are bent upwardly along the bend lines to form a friction fit with the drain wall; and (b) after the inserting step, applying a gas impermeable but water soluble sealant between the periphery of the device body and the drain wall to seal any gaps between the device body and the drain wall.