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US 4,832,773 AGranted
Techniques for welding thermoplastic tubes
AssigneeDenco, Inc.
InventorsJohn B. Shaposka, Dudley W. C. Spencer
Life of this patent
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AssigneeDenco, Inc.
InventorsJohn B. Shaposka, Dudley W. C. Spencer
Estimating the term…
Thermoplastic tubes are welded together in a dry condition with the tubes being open and maintained in their undistorted condition during the welding step. In an alternative technique a branch tube is welded to a main tube by placing the tubes in a non-parallel orientation in a holding device. A wafer cuts completely through one tube to form two tube sections. The wafer also cuts a notch from the other tube. One of the tube sections is shifted to become aligned with the notched other tube and welded thereto. A further technique includes placing at least one tube in a holding device which has a false floor for pressing against an area of the tube while the tube is being flattened at two spaced locations on opposite sides of the area. When the false floor is moved away from the tube a partial vacuum results. An air pocket is formed when the tube is severed by a wafer by air flowing into the cut tube.
In a device for welding the cut ends of two fluid filled thermoplastic tubes wherein each of the tubes is placed in a holding device and a cutting means cuts through each tube to create two pairs of cut ends and wherein a cut end of each pair is aligned and heated and then pressed together to become welded, the improvement being in that one of said holding devices comprising a first pair of clamping jaws for compressing a first tube at a first location, the other of said holding devices comprising a second pair of clamping jaws spaced from said first pair of clamping jaws with a gap therebetween, said second pair of clamping jaws compressing the first tube at a second location with fluid being in the first tube between the first and second locations, and means for creating a partial vacuum in the first tube between said first location and said second location whereby an air pocket is created in the first tube at said gap when said cutting means cuts through the first tube at said gap.
In a method of welding the cut ends of two fluid filled thermoplastic tubes wherein each of the tubes is placed in a holding device, a cutting means cuts through each tube to create two pairs of cut ends, a cut end of each pair being aligned and heated and pressed together to become welded, the improvement being in that at least one of the tubes is placed in a pair of spaced clamping units with a gap between the clamping units, flattening the at least one tube at two spaced locations to seal the at least one tube at those locations with fluid in the at least one tube between the locations and with the gap being between the locations, and creating a partial vacuum at the gap to create an air pocket when the at least one tube is cut so that the at least one tube may be cut at the gap without discharging the fluid.
Dependencies are inferred from the claim text.