Process for pipe seal manufacture
AssigneeAdvanced Elastomer Systems, L.P.
InventorsJeffrey Smith, Duane Peterson, Harold Seymour
Life of this patent
Estimating the term…
Abstract
Process for forming an annular member by extruding a thermoplastic profiled strip at an elevated temperature. Prior to cooling the strip, the still-molten ends undergo in-line compression molding to form an annular member having a joint section. The cross-section of the annular member is continuous in the joint section and the remainder of the body. Preferably, the extrudate may contain a thermoplastic elastomer, more preferably a thermoplastic vulcanizate formed by a dynamic vulcanization process. During the extrusion and compression molding processes, the extrudate may be supported on a rotatable turntable, or alternately on a rotatable molding cylinder.
Claims18
A process comprising:
- (a) extruding a strip of molten thermoplastic material through an extrusion die wherein the strip has a generally continuous cross-sectional profile and a leading end and a trailing end;
- and,
- (b) subsequent to (a) and without substantially cooling the strip, joining the leading end and the trailing end to form a joint therebetween by compression molding of the leading and trailing ends at a temperature sufficiently high to allow plastic flow in the area of the joint.
A process comprising:
- (a) extruding a thermoplastic elastomeric material onto a movable fixture to provide an extrudate having a leading end, wherein the extrudate exits an extruder die at an elevated predetermined temperature;
- (b) interrupting the extruding of the material to produce a trailing end of the extrudate;
- (c) moving the fixture during at least a portion of (a) so as to bring the leading end of the extrudate to a predetermined relationship to the trailing end;
- and,
- (d) before the extrudate cools to a predetermined cooled temperature, engaging the leading end and the trailing end in a mold under pressure to form a joint, wherein an annular member of the material is formed.
An apparatus comprising:
- an extruder having an exit die for forming a polymer extrudate having a leading end;
- an implement for severing later extruded polymer extrudate to create a trailing end;
- a rotatable fixture having a deposit-receiving surface for receiving the polymer extrudate, wherein the rotatable fixture is operable to return the leading end of extrudate to a position in contact with the trailing end;
- and,
- a compression molding mechanism, wherein the compression molding mechanism is adapted to cooperate with the rotatable fixture to form a joint in the polymer extrudate at a position where the leading end and trailing end are in contact.
Dependencies are inferred from the claim text.