US 2647374 A
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1953 c. w. STONER ANTISWEAT ANTIFROST ATTACHMENT INVENTOR -CHARLE.S WARD STONER Filed March 25, 1952 Patented Aug. 4, 1953 UNITED STATES PATENT OFFICE 6 Claims.
This invention appertains to refrigeration, and more particularly to refrigerator cabinets of the home or farm freezer type.
In home and farm freezers, refrigerator display cabinets and the like, the interior temperature of the cabinet is maintained at a low point, and in spite of good insulation the temperature around the cover or door of the cabinet is usually below the temperature of the surrounding air, consequently, condensation of moisture takes place around the opening of the cabinet. This moisture, in many instances, freezes around the cabinet.
One of the primary objects of my invention is the provision of means whereby the temperature around the cover or door of a refrigerator or like cabinet is maintained above the dew point of the surrounding air, so that the condensing of moisture and icing up of the walls of the opening of the cabinet is prevented.
Another salient object of my invention is the provision of an enclosed loop of refrigerator tubing mounted on the inside surface of the outer cabinet shell directly under and in' close proximity to the cabinet breaker strip or the wall of the cabinet opening, with means for causing the circulation of warm liquid through the loop to effectively raise the temperature of the cabinet around the cover or door opening above the dew point of the surrounding air, whereby the collection of moisture around the opening will be eliminated.
A further important object of my invention is the provision of means for forming the enclosed loop and for heating the liquid in the loop in such a manner that the flow of liquid through the loop in one direction is assured.
A still further object of my invention is to provide a simple and inexpensive means'for raising the temperature of the wall of a refrigerator cabinet around the opening therein, which can be readily incorporated with a standard cabinet during the fabrication thereof.
With these and other objects in view, the invention consists in the novel construction, formation and arrangement of parts as will be hereinafter more specifically described and claimed and illustrated in the accompanying drawing, in which drawing,
Figure 1 is a perspective view of a home or farm freezer with my invention incorporated therewith, parts of the View being shown broken away and in section to illustrate structural detail.
Figure 2 is an enlarged fragmentary transverse sectional view through the cabinet taken on the line 2-2 of Figure 1, looking in the direction of the arrows.
Referring to the drawing in detail, wherein similar reference characters designate corresponding parts throughout the several views the letter F generally indicates a home or farm freezer of a type now found in the open market. The'freezer F includes a cabinet 5 having the usual body 6 and a cover I for normally closing the upper open end of the body. In accordance with the usual practice, the body 6 includes inner and outer shells 8 and 9 with desired insulation I0 therebetween. The shells 3 and 9 are joined at their upper ends by a breaker strip H. The cover 1 carries a cushioning gasket ii for engaging tight against the breaker strip II, when the cover is in its closed position for sealing the cabinet. The inner shell 8 has placed thereabout the tubing l3 for the refrigerant and the inner face of the shell 8 and the tubing are covered by suitable mastic. The cabinet itself is provided with a compartment at one end for receiving the compressor unit M and the other necessary adjuncts.
In accordance with my invention, I build within the cabinet body 6 an enclosed or endless loop l5 of tubing. The tubing is preferably formed from copper and is the same type as is utilized for the refrigerant tubing 53. The loop [5 of tubing is placed on the inside surface of the outer shell 9 directly under the breaker strip H, as is clearly shown in Figure 2, and the loop can be sprung in place under the upper flange of the shell 9. Hence, the loop l5 lies in close proximity to the outer wall of the opening in the cabinet body 6 adjacent to the cushioning gasket l2. Formed in an intermediate part of the loop I 5 is a depending U-shaped loop or leg it including substantially vertically extending stretches I1 and i8 joined at their lower ends by a bight l9. One of the stretches, i. e., the stretch H, has formed therein intermediate its ends a laterally extending U-shaped loop 20 and coiled. about this loop 20 is a resistance heater coil 2|. The terminals of the resistance coil are connected by suitable wiring 22 to a humidistat or thermostat 23 disposed in the power line source. This humidistat or thermostat 23 includes an element 24 preferably located exteriorly of the cabinet 5. The depending U-shaped loop 16 forms a static trap and the heater loop 20 forms an admirable means for heating a liquid within the closed loop l5; it being understood that the closed loop I5 contains a suitable liquid. The combination of the static trap 16 and the heater loop 20 makes 3 possible the flow of warmed fluid in only one direction in loop l5 when heat is supplied to the heater loop 20.
The closed loop of refrigerant tubing provided with the trap loop l6 and the heater coil loop makes it possible to remove and replace resistance heater 2! easily and quickly. Thus, this system has advantages over other systems, which are not of the continuous loop or secondary system type. Likewise, the chances for leaks in the refrigerating system itself are minimized and the motor compressor unit M can be easily removed for repairs or replacement without disturbing the closed loop I 5 or vice versa.
The position of the closed loop is such that the upper edge of the body of the cabinet around the entrance opening is heated at a direct point engaged by outside air and consequently the depositing of moisture around the wall of the en trance opening is eliminated.
A humidistat will operate the anti-sweat attachment satisfactorily, providing the element 24 is located on the outside of the cabinet, as shown, out and away from the heat generated by the condensing unit. Where a thermostat is utilized, its element is also placed exteriorly of the cabinet, with the element in the ambient temperature or dry bulb temperature of the room, set to cut in at room temperature and cut out at a few degrees above the room ambient temperature. This method of control is satisfactory because when sweating occurs on the surfaces of a cabinet, the dew point temperature is near the dry bulb temperature and approaches the dry bulb temperature, reaching dry bulb temperature at saturation or 100% relative humidity.
By providing the humidistat or thermostat 23, the liquid can be warmed only when the humidity .of outside air is high and the supply of current to .the resistance coil can also be cut off in case temperatures rise to an unwanted degree.
I prefer to fill or partially fill the closed loop I5 with refrigerant or other volatile liquid to enhance the circulation of fluid in the loop. The liquid is heated in the heater loop 20 by the resistance Wire 21, and is volatilized and flows through the loop and gradually becomes cooled by its contact with the breaker strip and returns to a liquid and drops into the trap loop [6, where the same again becomes heated by the resistance coil.
While I have shown my invention applied to a home or farm freezer, it is to be understood that the same can be used with equal advantages in refrigerator display cabinet and other like appliances.
Changes in details may be made without departing from the spirit or the scope of this invention, but what is claimed as new is:
1, In a refrigerating cabinet having an opening and a door for closing said opening, means for heating the wall of the cabinet around the opening in close proximity to the door for raising the temperature of the cabinet around the door above the dew point of the air surrounding the cabinet including a closed loop of tubing having a liquid therein, said closed loop including a depending U-shaped static trap defining spaced stretches, a laterally extending loop formed in one of the stretches and means for heating the laterally extending loop.
2. In a refrigerating cabinet as defined in claim 1, and said means for heating the laterally extending loop including an electric resistance heater wire wound about said laterally extending loop.
3. In a refrigerating cabinet as defined in claim 2, and means for opening and closing the circuit to the electric resistance heater coil according to the humidity of the air surrounding the cabinet.
4. In a refrigerating cabinet as defined in claim ,2, and means ior opening and closing the circuit to the electric resistance heater coil according to the temperature of the air surrounding the cabinet.
'5. In a refrigerating cabinet having a body provided with an opening, a door for closing the opening, a refrigerating circuit for the body including a motor driven compressor, means independent of the refrigerating circuit for raising the temperature of the wall of the cabinet surrounding the opening above the dew point of the air about the cabinet including a closed loop of tubing disposed in the cabinet in close proximity to the door opening and door having a liquid therein, and means at one point in said closed loop for heating liquid therein, said closed loop also including a depending static trap having spaced stretches, and a laterally extending loop formed in one of the stretches, and means for heating the laterally extending loop.
6. In a refrigerating cabinet having a body provided with an opening, a door for closing the opening, a refrigerating circuit for the body including a motor driven compressor, means independent of the refrigerating circuit for raising the temperature of the wall of the cabinet surrounding the opening above the dew point of the air about the cabinet including a closed loop of tubing disposed in the cabinet in close proximity to the door opening and door having a liquid therein, and means at one point in said closed loop for heating liquid therein, and said loop in-.- cluding a depending U-shaped trap having spaced stretches, one of said stretches being provided with a laterally extending U-shaped loop, the liquid in the closed loop being heated at the point where the liquid passes through the laterally extending loop, said closed loop being removable from the cabinet independent of the refrigerating mechanism for the cabinet.
CHARLES WARD STONER.
References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,155,261 Fiene Apr. 18, 1939 2,238,511 Thaxter Apr. 15, 1941 2,444,667 'Philipp July 6, 1948 2,509,784 Roth May 30, 1950