Heating apparatus for fluid flow channel

Abstract

Apparatus for heating a fluid being injected in an injection molding system, the apparatus comprising a mold having a cavity, a fluid flow distribution manifold, a fluid flow channel body, a coiled heater tube comprised of a thermally conductive wall, a heater device disposed within the coiled tube; the coiled tube having an upstream, downstream and intermediate coiled portions, the upstream and downstream coiled portions of the coiled tube being selectively movable away from each other along the coil axis to cause the intermediate coiled portion of the coiled tube to stretch or extend in coil axial length.

1 . In an injection molding system, a method of heating a fluid flow channel body that defines a fluid flow channel that communicates fluid flow to a mold of a cavity mounted in the system, the fluid flow channel having an axis, the method comprising:
 forming a hollow tube having a thermally conductive wall that surrounds and forms a hollow interior bore housed by the wall of the tube;   forming the hollow tube into a coil configuration having a coil axis, an upstream coiled portion and a downstream coiled portion interconnected by an intermediate coiled portion and disposing a heating device within the bore of the hollow tube;   mounting the coiled tube around an outside surface of the fluid flow channel body in thermally conductive communication with the fluid flow body;   attaching one of the upstream or downstream coiled portions to the fluid flow channel body   moving the upstream and downstream coiled portions axially away from each other a selected distance along the coil axis, the intermediate coiled portion extending in coil axial length on movement of the upstream and downstream coiled portions away from each other;   controllably heating the heating device to a selected temperature.   
     
     
         2 . The method of  claim 1  further comprising mounting the upstream coiled portion and the downstream coiled portion to upstream and downstream tubular collars and attaching the upstream and downstream coiled portions to the fluid flow channel body subsequent to the step of moving. 
     
     
         3 . The method of  claim 1  wherein the intermediate coiled portion has a first cross-sectional diameter prior to the intermediate coiled portion being extended, the method further comprising rotating the upstream coiled portion and the downstream coiled portion relative to each other around the fluid flow channel axis to a degree and in a direction selected to reduce the first diameter to a second smaller diameter wherein the inside circumferential surface of the intermediate coiled section engages against the fluid flow channel under pressure. 
     
     
         4 . The method of  claim 1  wherein step of forming the hollow tube into a coil configuration comprises forming the upstream, downstream and intermediate coiled portions to have a selected number of coils per unit of length along the coil axis extending along said portions, the step of moving comprising maintaining the selected the number of coils constant per unit of length of the coil axis along the upstream and downstream coiled portions during performance of the step of moving and reducing the number of coils per unit of length of the coil axis along the intermediate coiled portion during the step of moving. 
     
     
         5 . The method of  claim 1  wherein the step of forming the hollow tube into a coil configuration comprises forming the upstream, downstream and intermediate coiled portions to each have a selected cross-sectional diameter, the step of moving comprising maintaining the selected cross-sectional diameter of the upstream and downstream coiled portions substantially constant during the step of moving and reducing the cross-sectional diameter of the intermediate coiled portion during the step of moving. 
     
     
         6 . The method of  claim 5  wherein the upstream and downstream coiled portions are moved away from each other a distance sufficient to cause the intermediate coiled portion to engage an outside surface of the fluid flow channel body. 
     
     
         7 . In an injection molding system, a method of heating a fluid flow channel body that defines a fluid flow channel that communicates fluid flow to a mold of a cavity mounted in the system, the fluid flow channel having an axis, the method comprising:
 forming a hollow tube having a thermally conductive wall that surrounds and forms a hollow interior bore housed by the wall of the tube;   forming the hollow tube into a coil configuration having a coil axis, an upstream coiled portion and a downstream coiled portion interconnected by an intermediate coiled portion;   disposing a heating device within the bore of the hollow tube;   mounting the coiled tube around an outside surface of the fluid flow channel body;   attaching one of the upstream or downstream coiled portions to the fluid flow channel body and rotating the other of the upstream and downstream coiled portions around the axis of the coiled tube to cause the intermediate coiled portion to reduce in radial diameter so as to engage the outside surface of the fluid flow channel;   controllably heating the heating device to a selected temperature.   
     
     
         8 . In an injection molding system, a method of heating a fluid flow channel body that defines a fluid flow channel that communicates fluid flow to a mold of a cavity mounted in the system, the fluid flow channel having an axis, the method comprising:
 forming a hollow tube having a thermally conductive wall that surrounds and forms a hollow interior bore housed by the wall of the tube;   forming the hollow tube into a coil configuration having a coil axis, an upstream coiled portion and a downstream coiled portion interconnected by an intermediate coiled portion;   disposing a heating device within the bore of the hollow tube;   mounting the coiled tube around an outside surface of the fluid flow channel body;   attaching one of the upstream or downstream coiled portions to the fluid flow channel body;   moving the upstream and downstream coiled sections axially away from each other a distance sufficient to reduce the intermediate coiled portion in radial diameter so as to engage the outside surface of the fluid flow channel;   controllably heating the heating device to a selected temperature.