Patent US3813896A successfully refreshed from Google Patents.
US3813896A
Expired / Lapsed
US
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Freezer air vent
Assignee: SHANNON REFRIGERATION Inc
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Filing: 1973-01-26
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Granted: 1974-06-04
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Expires: 1993-01-26
Abstract
Abstract An air vent extends through one wall of a freezing chamber and communicates with the outside atmosphere through a vacuum relief valve and a pressure relief valve. When a partial vacuum condition develops within the freezing chamber due to the removal of airborne moisture by the freezing process, a vacuum-responsive element in the vacuum relief valve opens and admits atmospheric air into the freezing chamber to relieve the partial vacuum. When an increase of pressure develops within the freezing chamber due to the closing of the freezer door, a pressure-responsive element in the pressure relief valve opens to relieve the increase of pressure. A heater coil is wound around the interior of the air vent to prevent it from becoming clogged with ice.
Inventors
- 👤 A Lebahn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 08:14
CPC Classifications
F; F25; F25D; F25D17/00; F25D17/04; F25D17/042; F25D17/047; Y; Y10; Y10T; Y10T137/00; Y10T137/7722; Y10T137/7771; Y10T137/778
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
193 words
In an enclosed freezing chamber having refrigerating means and having a door through which moist, atmospheric air may enter the freezing chamber, the improvement comprising an air vent extending through one wall of said freezing chamber and a vacuum relief valve in said air vent and having a valve element which is responsive to a partial vacuum condition created within the freezing chamber by the removal of moisture from moist air therein as a result of the refrigerating action, said valve element admitting air into the interior of said freezing chamber to relieve said partial vacuum, said vacuum relief valve comprising a hollow valve housing coupled to said air vent, an opening in the bottom of said valve housing communicating with the atmosphere, a valve seat within said valve housing above said opening, and a gravity-biased valve element shaped to normally rest upon said valve seat and form an air seal therearound, and said valve element being light enough to be lifted in response to said partial vacuum condition within said freezing chamber, thereby breaking said air seal and admitting air into the interior of said freezing chamber to relieve said partial vacuum.
Claim 2
Dependent Claim
193 words
In an enclosed freezing chamber having refrigerating means and having a door through which moist, atmospheric air may enter the freezing chamber, the improvement comprising an air vent extending through one wall of said freezing chamber and a vacuum relief valve in said air vent and having a valve element which is responsive to a partial vacuum condition created within the freezing chamber by the removal of moisture from moist air therein as a result of the refrigerating action, said valve element admitting air into the interior of said freezing chamber to relieve said partial vacuum, said vacuum relief valve comprising a hollow valve housing coupled to said air vent, an opening in the bottom of said valve housing communicating with the atmosphere, a valve seat within said valve housing above said opening, and a gravity-biased valve element shaped to normally rest upon said valve seat and form an air seal therearound, and said valve element being light enough to be lifted in response to said partial vacuum condition within said freezing chamber, thereby breaking said air seal and admitting air into the interior of said freezing chamber to relieve said partial vacuum.
Claim 3
Dependent Claim
42 words
The improvement defined in claim 1 wherein said valve element comprises a lightweight ball and further comprising a stop element within said valve housing above said ball to prevent the ball from being drawn into said air vent by said partial vacuum.
Claim 4
Dependent Claim
90 words
The improvement defined in claim 1 and further comprising a second opening in the top of said valve housing communicating into the atmosphere, a second valve seat within said valve housing below said second opening, and a second gravity-biased valve element shaped to normally rest upon said second valve seat and form an air seal therearound, and said second valve element being light enough to be lifted in response to an increase in air pressure within said freezing chamber, thereby breaking said air seal and relieving said increase of pressure.
Claim 5
Dependent Claim
34 words
The improvement defined in claim 3 wherein said valve elements each comprise a hollow plastic ball and further comprising stop elements within said valve housing above said balls to limit the upward movement thereof.
Claim 6
Dependent Claim
14 words
The improvement defined in claim 1 wherein said valve element comprises a lightweight ball.
Claim 7
Dependent Claim
36 words
The improvement defined in claim 5 in which there is a stop element within said valve housing above said lightweight ball to prevent the ball from being drawn into said air vent by said partial vacuum.
Claim 8
Dependent Claim
15 words
The improvement defined in claim 3 wherein said valve elements each comprise a lightweight ball.
Claim 9
Dependent Claim
27 words
The improvement defined in claim 7 wherein there is a stop element within said valve housing above each of said balls to limit the upward movement thereof.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-03 | 1977-12-03 | 1978-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-03 | 1981-12-03 | 1982-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-03 | 1985-12-03 | 1986-06-04 | $7700.00 | Window Closed / Lapsed |