Welding of filled sintered polytetrafluoroethylene

Claim 1

A method for welding a pair of filled, sintered, polytetrafluoroethylene components to one another comprising the steps of a. forming of said components to have an overlap portion, b. tapering each of said overlap portions at equal angles to form planar reverse mated surfaces each having a length not substantially less than 1/2", c. assembling said components in a press with the reverse mated surfaces in relatively opposed relationship and in the absence of other material therebetween, d. clamping the assembled components in place directly across the area of the reverse mated surfaces to prevent relative movement of said surfaces, e. applying heat and pressure sufficient to fuse said reverse mated surfaces without material thinning of the area under pressure as the pressure increases from an initial positive level to a higher level due to thermal expansion, and f. cooling the resultant fused assembly at a positive pressure less than the initial pressure of step e.

Claim 2

A method for welding a pair of filled, sintered, polytetrafluoroethylene components to one another comprising the steps of a. forming of said components to have an overlap portion, b. tapering each of said overlap portions at equal angles to form planar reverse mated surfaces each having a length not substantially less than 1/2", c. assembling said components in a press with the reverse mated surfaces in relatively opposed relationship and in the absence of other material therebetween, d. clamping the assembled components in place directly across the area of the reverse mated surfaces to prevent relative movement of said surfaces, e. applying heat and pressure sufficient to fuse said reverse mated surfaces without material thinning of the area under pressure as the pressure increases from an initial positive level to a higher level due to thermal expansion, and f. cooling the resultant fused assembly at a positive pressure less than the initial pressure of step e.

Claim 9

A method for welding a plurality of filled, sintered, polytetrafluoroethylene components to one another, wherein N equals the total number of said components, and comprising the steps of: a. forming each of said components to have an overlap portion, b. tapering each of said overlap portions at equal angles to form planar reverse mated surfaces each having a length not substantially less than 1/2", c. assembling said components in a press with the reverse mated surfaces in relatively opposed relationship and in the absence of other material therebetween, d. clamping the assembled components in place directly across the area of the reverse mated surfaces to prevent relative movement of said surfaces, e. applying heat and pressure sufficient to fuse said reverse mated surfaces without material thinning of the area under pressure as the pressure increases from an initial positive level to a higher level due to thermal expansion, f. cooling the resultant fused assembly at a positive pressure less than the initial pressure of step e, and g. repeating steps a to f an additional N-1 times to weld successive pairs of reverse mated surfaces to form a continuous and endless element.

Claim 10

A method for welding a plurality of filled, sintered, polytetrafluoroethylene components to one another, wherein N equals the total number of said components, and comprising the steps of: a. forming each of said components to have an overlap portion, b. tapering each of said overlap portions at equal angles to form planar reverse mated surfaces each having a length not substantially less than 1/2", c. assembling said components in a press with the reverse mated surfaces in relatively opposed relationship and in the absence of other material therebetween, d. clamping the assembled components in place directly across the area of the reverse mated surfaces to prevent relative movement of said surfaces, e. applying heat and pressure sufficient to fuse said reverse mated surfaces without material thinning of the area under pressure as the pressure increases from an initial positive level to a higher level due to thermal expansion, f. cooling the resultant fused assembly at a positive pressure less than the initial pressure of step e, and g. repeating steps a to f an additional N-1 times to weld successive pairs of reverse mated surfaces to form a continuous and endless element.