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Publication numberUS2945954 A
Publication typeGrant
Publication dateJul 19, 1960
Filing dateJun 30, 1958
Priority dateJun 30, 1958
Publication numberUS 2945954 A, US 2945954A, US-A-2945954, US2945954 A, US2945954A
InventorsRichard S Gaugler
Original AssigneeGen Motors Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Refrigerating apparatus
US 2945954 A
Abstract  available in
Previous page
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Claims  available in
Description  (OCR text may contain errors)

July 19, 1960 R. s. GAUGLER 2,945,954

REFRIGERATING APPARATUS Filed June 50, 1958 INVENTOR. ,R/ch 0rd 8. Gaug/er.

BY 5; Q8

His Attorney.

Fig. .2

a p 2,945,954 a Patented July REFRIGERATING APPARATUS Delaware Filed June so, 1958, Ser. No. 745,601

This invention relates to refrigerating apparatus and more particularly to a method and apparatus for indicating temperature variations over a wall area of a refrigerator cabinet or the like.

it is an object of this invention to utilize thermographic phosphorous for detection or measurement of variations of temperature in different parts of a food compartment of a refrigerator.

It is another object of this invention to provide improved means for detecting imperfections in wall insulation.

More particularly it is an object of this invention to provide an improved arrangement for applying thermographic phosphorous to various surfaces of a refrigerator whereby it is possible to use the thermographic phosphorous material over and over again.

Thus it is an object of this invention to place a layer of thermographic phosphorous on a thin film of material having a high electrostatic charge which will cause the film to adhere to the surface being tested.

Further objects and advantages of the present inven tion will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings:

*Figure 1 is a perspective view showing a refrigerator having means for visually indicating temperature variations in different parts of a refrigerator cabinet and for testing for imperfections in the wall insulation; and

Figure 2 is a perspective view, on an exaggerated scale, of a film used in detection of variations of temperature.

Referring now to the drawing, reference numeral designates a conventional household refrigerator cabinet having a frozen food storage compartment 12 provided in the upper portion of the cabinet and a refrigerated food storage compartment 14 in the lower portion of the cabinet. For purposes of illustration the cabinet shown is of the type which has an insulated door 16 for closing the frozen food storage compartment 12 and a separate insulated door 18 for closing the food storage compartment 14.

In the refrigerator shown for purposes of illustrating the invention, the inner liner 20 for the frozen food storage compartment 12 is in the form of a sheet metal evaporator which serves to refrigerate the contents of the compartment 12. The compartment 14 may be refrigerated in any conventional manner such as by heat leakage cfrom the evaporator 20 into the lower compartment 14 or by a separate evaporator (not shown) disposed directly in the compartment 14 or in an air flue adjacent the compartment 14. Reference numeral designates a conventional refrigerant liquefying unit for supplying liquid refrigerant to the evaporator in accordance with conventional practice.

It has been found that imperfections in the insulation forming the walls of the refrigerator can be detected by applying'a layer of thermographic phosphorous material 32 to the outside wall of the cabinet while heat is being added to the interior of the refrigerator and then exposing the thermographic phosphorous material to ultraviolet radiation from any suitable source such as that shown at 33. When the' thermographic phosphorous material is exposed to ultraviolet radiation. differences in temperature 'on various parts of the surface to which the thermographic phosphorous material is applied will cause the thermographic phosphorous material to exhibit marked changes of brightness with difierences of temperature. Thus imperfections in the insulation would cause the coating to appear much darker at the points where the insulation was inadequate. Any suitable source of heat, such as an electric heater, could be used for heating the interior of the refrigerator.

The thermographic phosphorous material and its properties are well known and may be of the type disclosed in US. Patent No. 2,642,538 and sold by the US. Radium Corporation of Norristown, New Jersey, under the trademark Radelin Phosphor No. 1807. The usual practice of applying the thermographic phosphorous in the form of paint which is applied directly to the surface to be tested has the disadvantage that the amount of material required to paint a large number of objects is objeotionable and furthermore the need for removing the thermographic material from the surface at the completion of the test presents a problem. According to this invention, thermographic material 22 (see Figure 2) is applied to a sheet of material 24 such as Mylar, polyethylene, Saran (a copolymer of vinyl chloride and vinyldiene chloride), or Hycar vinyl (a mixture of vinyl chloride-vinyl acetate copolymer and butadiene-acrylonitrile copolymer). Films of this material will take a high electrostatic charge and will therefore adhere very closely to any surface on which the film is placed with the result that the film will have a temperature corresponding to the temperature of the surface to which it adheres. By applying such a film to either an inner or outer wall of a refrigerator cabinet and exposing the film to ultraviolet light, slight variations in temperature can readily be detected by visual observation. The Mylar or other plastic film is preferably between .0005 and .001 inch thick and the thickness of the thermographic phosphorous material is preferably .005 inch.

in Figure l of the drawing a film 30 has been applied to an inner side wall of the refrigerator and a film 32 has been applied to an outer side wall of the refrigerator. By applying the film to the inside wall in this manner and then closing the door and operating the refrigerator for a period of time long enough to stabilize the temperatures therein and then opening the door and exposing the film to ultraviolet light, the film will readily show up differences in the temperature in different parts of the refrigerator. Likewise by placing a sheet or film of the material 32 on an exterior surface of a refrigerator in operation any imperfection in the insulation within the refrigerator will cause a spot or spots to show up in the thermographic phosphorous material. In place of checking variations in brightness of the film 32 while the refrigerator is in operation, one could apply heat within the refrigerator while the refrigeration system is inoperative and then check the brightness of the film to detect imperfections in the insulation as explained hereinabove.

For purposes of illustration the film has been shown applied directly to the flat wall portions of the refrigerator cabinet but due to the flexibility of the film material it can be used very efiectively in testing temperature differences across the breaker strip and other parts of the cabinet since the electrostatic charge which is inherent in t place on the surface to be checked.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, as may come within the scope of the claims which follow.

What is claimed is as follows:

1. The method of testing temperature differentials in different parts of refrigerator cabinets which comprises suspending a sheet of thermographic phosphorous material within a food compartment of a refrigerator cabinet, directing ultraviolet light onto said thermographic material and observing the amount of light admitted on ditferent portions of said thermographic material.

2. The method of testing temperature differentials in difierent parts of refrigerator cabinets which comprises electrostatically adhering to the wall of a refrigerator a flexible sheet having thereon a coating of thermographic phosphorous material, directing ultraviolet light onto said thermographic material and observing the light intensity on different portions of said thermographic material.

References Cited in the file of this patent UNITED STATES PATENTS

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2333641 *Mar 28, 1940Nov 9, 1943Minnesota Mining & MfgLuminous adhesive sheet
US2434448 *Nov 1, 1945Jan 13, 1948Seeger Refrigerator CoMethod of detection of small leaks in receptacles
US2614430 *Feb 1, 1950Oct 21, 1952Eastman Kodak CoTemperature indicating device
US2642538 *Feb 11, 1949Jun 16, 1953Eastman Kodak CoThermal radiography using phosphors
US2694153 *Aug 3, 1950Nov 9, 1954Frederic W ReuterX-ray intensifying screen
US2817767 *Nov 23, 1953Dec 24, 1957Haloid CoXerographic development
US2834891 *Mar 5, 1954May 13, 1958Hupp CorpRadiation detection methods and devices
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3102197 *Dec 12, 1960Aug 27, 1963Bausch & LombRadiation dosimetry and plastics compositions therefor
US3249930 *Feb 4, 1960May 3, 1966Thompson Ramo Wooldridge IncParametric visual system indicator
US3256518 *Jul 27, 1959Jun 14, 1966Crane Hewitt DThermochromic indicating system
US3406285 *Oct 19, 1966Oct 15, 1968Westinghouse Electric CorpMethod of inspection of soldered joints comprising using a volatile fluorescent dye
US3591810 *Apr 15, 1969Jul 6, 1971Hawker Siddeley Dynamics LtdTemperature monitoring apparatus using a photochromic heat sensor
US3869918 *Aug 1, 1973Mar 11, 1975Atomic Energy CommissionTemperature measurement device
US3965360 *Aug 19, 1974Jun 22, 1976Nippon Kokan Kabushiki KaishaMethod for discriminating high-temperature red heated material
US4075493 *Dec 16, 1976Feb 21, 1978Ronald AlvesOptical temperature measurement technique utilizing phosphors
US4215275 *Feb 15, 1978Jul 29, 1980Luxtron CorporationOptical temperature measurement technique utilizing phosphors
US4223226 *Jul 26, 1978Sep 16, 1980Rockwell International CorporationFiber optic temperature sensor
US4374328 *Apr 27, 1981Feb 15, 1983Gould Inc.Photoluminescent indicator
US8544286 *Sep 14, 2006Oct 1, 2013Brian D. JanssenSystem including electronic based temperature monitoring device and optional integrated cooler for maintaining a temperature of such as injectables
U.S. Classification250/459.1, 250/461.1, 62/125, 374/137, 62/129
International ClassificationF25D29/00
Cooperative ClassificationF25D29/00
European ClassificationF25D29/00