Process for fabricating crosslinked polyethylene tubing ends
OwnerWilliam Rowleyinventor
Life of this patent
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Abstract
A unitary molded crosslinked polyethylene tubular connector and method for forming the connector with various end configurations (e.g., molded, belled) is described). The process combines the ease of thermoplastic processing combined with the desirable physical properties of a thermoset. The connector is suitable as a replacement for copper tubes with associated fittings as well as polybutylene tubing.
Claims31
A process for forming a unitary molded tubular connector having at least one integrally molded end cap with a first internal diameter at one end of the connector, a tubular segment having a first internal diameter equal to that of the end cap and a first outer diameter and a thickness as measured as the difference between the first internal diameter and the first outer diameter, the tubular segment originating from the end cap, the connector being formed from a uniform thickness hollow cylindrical tube of the same thickness as the tubular segment, comprising the steps, without regard to order of steps (a) and (b):
- (a) molding an end cap comprising the steps in the following order of:
- (i) inserting a first end of the tubular connector through a female end cap die, the die surrounding the first outer diameter of the tubing connector and having a cylindrical projection adapted to cooperate with a recess of a male end cap die;
- (ii) holding the tubular connector from the female end cap die with the end cap to be formed projecting from the female end cap die, the female and male end cap dies being separated;
- (iii) heating the portion of the tubular connector projecting from the female end cap die sufficiently to make such projecting portion pliable enough to form;
- and
- (iv) forming the heated portion of the tubular connector into an end cap by the cooperation of the cylindrical projection of the female end cap die and recess of the male end cap die by closing the female and male end cap dies, the end cap further comprising:
- an end face, a sealing means and a flange having a shoulder and further having a centrally disposed aperture therethrough;
- and
- (b) crosslinking the tube with a crosslinking agent.
A process for forming at least one belled tubular end without wall thinning from a constant thickness portion of a hollow cylindrical tube comprising the steps without regard to order of steps (a) and (b):
- (a) molding a belled end comprising the steps in the following order of:
- (i) inserting an end of the tubular connector through a female belling die, the die surrounding a first outer diameter of the tubular connector and having a cylindrical projection adapted to cooperate with a recess of a male belling die;
- (ii) holding the tubular connector from the female belling die with the belled end to be formed projecting from the female belling die, the female and male belling dies being separated;
- (iii) heating the portion of the tubular connector projecting from the female belling die sufficiently to make such projecting portion pliable enough to form;
- and
- (iv) forming the heated portion of the tubular connector into the belled end by the cooperation of the recess of the male belling die and the projection of the female belling die by closing the female and male belling dies;
- and
- (b) crosslinking the tube with a crosslinking agent.
The process of claim 25 wherein the molded tubular connector is polyethylene and the temperature of step (iii) of claim 28 is from about 700.degree. F. for about 15-35 seconds.
Dependencies are inferred from the claim text.