Turbocharger drain line with reinforced flexible conduit

Claim 1

In a turbocharger drain line interconnecting a turbocharger housing and the block of an internal combustion engine on which the turbocharger is used, the drain line adapted for returning lubricating oil from the turbocharger to the engine lubricating system, a flexible tubular conduit forming a portion of said drain line, said conduit comprising an integral tubular wall having inner and outer adhered, coaxial layers, said inner layer defining the conduit inner wall surface in contact with the fluid flowing therethrough and formed of a used lubricating oil resistant silicone rubber and said outer layer comprising at least one lamina formed of woven aromatic polyamide reinforcing fabric coated with a high modulus, high tear strength silicone rubber, said used lubricating oil resistant silicone rubber comprising a filled, heat vulcanizable silicone rubber composition including organopolysiloxane polymers and blends thereof having a viscosity of 1,000,000 to 200,000,000 centipoise at 25° C. and a curing catalyst, said rubber having a specific gravity in the cured state of 1.20 to 1.70, said high modulus, high tear strength silicone rubber having a Shore A-2 Durometer Hardness of 55, a tensile strength of 1350 psi, an elongation modulus of 250%, and a Die B tear strength of 300 ppi based upon a 0.075-inch-thick slab press cured for 10 minutes at about 171° C., said inner layer having a thickness up to about 0.04 inches, said outer layer comprising at least four adhered, coaxial lamina and each lamina having a thickness of 0.01 to 0.02 inches.