Tubular Heater With External Thermocouple

Abstract

The problems associated with the prior art have been overcome by the present invention, which describes a tubular heating element having a more reliable and accurate temperature monitoring system. The tubular heating element has a thermocouple attached to its exterior surface, in close proximity to the cutting and sealing portion of the tubular heating element. In addition to improving the accuracy of the temperature measurement, this technique reduces electromagnetic interference caused by the interaction between the heating wire and the thermocouple.

Description

[0001]This application claims priority of U.S. Provisional Patent Application Ser. No. 61 / 558,472, filed Nov. 11, 2011, the disclosure of which is incorporated herein by reference in its entirety.BACKGROUND OF THE INVENTION[0002]Machines used to wrap and seal articles and packages in thermoplastic film are well known in the art. Two types of machines are commonly referred to as side-sealing and lap-sealing machines. In the typical side-sealing configuration, an article or set of articles travels, typically via a conveyor belt, toward the machine. A sheet of center-folded plastic film, having two layers, is fed from a direction, which is preferably perpendicular to the direction of the conveyor. The two layers of the film are then separated such that the article is placed between the lower layer and the upper layer. On one side of the article is the center-fold, while on the other side, there is an open edge where the two layers are not attached. The machine has several sets of belts...

AI Technical Summary

Benefits of technology

The present invention is a better way to measure the temperature of a tubular heating element. It uses a thermocouple attached to the surface of the heating element to closely monitor the cutting and sealing process. This improves the accuracy of the temperature measurement and reduces interference caused by the heating element and the thermocoule.

Problems solved by technology

Incomplete, inconsistent or sloppy welds can be problematic with these types of machines.

One potential issue associated with any side sealing mechanism is the ability to accurately control the temperature of the heating element.

This proximity of the heating element introduces a source of error between the temperature being monitored and the actual temperature at the cutting surface.

In addition, the proximity of the heating element to the thermocouple may also cause electromagnetic interference which affects the reliability of the data received from the thermocouple.

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