Back seam welder and method of operation

摘要

A thermal welder is configured to weld a back seam of a bag formed of thermoplastic sheet material, which may be a polywoven material. The welder typically includes a weld heater and a compression mechanism downstream of the weld heater to compress the sheet material to form the back seam. The welder also includes a weld breaker downstream of the compression mechanism to break apart incidental welds which are formed adjacent the back seam.

主权项

1. A thermal welding apparatus comprising:
a sheet material pathway adapted to allow sheet material to move downstream therethrough while the sheet material is in a tubular configuration with a longitudinally extending overlap region; a weld heater extending adjacent the pathway, wherein the weld heater is configured to heat the overlap region to a weld temperature; a compression mechanism extending adjacent the pathway adjacent and downstream of the weld heater, the compression mechanism configured to compress the heated overlap region into a welded back seam; and a weld breaker within the pathway downstream of the compression mechanism; wherein the tubular configuration of the sheet material passes around the weld breaker such that the weld breaker passes through the interior of the tubular configuration and the weld breaker is adapted to disengage incidental welds created during formation of the back seam without the weld breaker removing any sheet material.