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Purge Control for Low Temperature Freezers

IP.com Disclosure Number: IPCOM000037579D
Original Publication Date: 1989-Mar-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Puffenbarger, S: AUTHOR

Abstract

This article describes a purge control for low temperature freezers and like enclosures which maintain a dry environment for products stored inside such freezers. Moisture that enters the freezer through infiltration or through opening and closing of the freezer lid is removed from the enclosure.

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This is the abbreviated version, containing approximately 84% of the total text.

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Purge Control for Low Temperature Freezers

This article describes a purge control for low temperature freezers and like enclosures which maintain a dry environment for products stored inside such freezers. Moisture that enters the freezer through infiltration or through opening and closing of the freezer lid is removed from the enclosure.

The purge control maintains a positive static pressure within the freezer through the action of the static pressure switch. The switch is connected to a tube which runs inside the freezer compartment. Upon a decrease in compartment static pressure, i.e., if the freezer lid is opened, the contacts of the static pressure switch will close and energize the purge and exhaust solenoid valves. The purge valve allows a regulated supply of dry air or nitrogen to flow into the freezer compartment and build to a static pressure. The exhaust valve serves as a means for moisture- laded air to leave the compartment as dry air enters. It also serves as a relief device to prevent excessive pressure from building in the freezer compartment and forcing open the seal on the freezer lid. When the purge valve builds a preset static pressure in the freezer compartment, the contacts on static pressure switch will open, deenergizing the purge and exhaust valves.

The purge control also employs a timed purge cycle which allows the compartment to be purged at regular intervals to remove accumulated moisture within the freezer compartment. Two timed delay...