Importance

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Abstract

An improved door closure indicator is provided. The indicator operates on pressure levels read within a pressurized chamber rather than from proximity switches coupled between the chamber and the door. If the door seals to the chamber, pressure within the chamber will quickly change, and the change will be read on a pressure sensor indicative of the door closure. According to one example, the chamber can comprise a vacuum chamber and the pressure sensor can be a vacuum monitor. Once vacuum is detected, it is determined with more absolutism that the door is actually closed rather than having to rely upon switch operation and/or alignment of the door activation mechanism to proximity switches arranged on the chamber housing. The processing tool which embodies the chamber includes a chamber controller which incorporates various switches and relays which channel pressure readings taken from the chamber to a load controller, and also delays pressure readings after opening a half-gate valve operably coupled between a vacuum pump and the chamber.

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First Claim