US 2130036 A
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Description (OCR text may contain errors)
p 1938- J. A. SHRADER 2,130,036
DEFROSTER Filed July 21, 1934 INVENTOR BY w y 1 ATTOR N EY Patented Sept. 13, 1938 UNITED STATES PATENT OFFICE 1 Claim.
This invention relates to a defroster for a refrigerator or similar device of the character having a cooling orfreezing unit and has for the primary object the provision of means for direct- 5 ing a blast of air onto .the cooling or freezing unit' at any selected period of time to bring about a thorough or rapid defrosting for removal of the snow or ice on the cooling or freezing unit and which may take place while the refrigerator or 10 similar device is closed to the atmosphere which permits the refrigerator to remain at a low or lower temperature than heretofore accomplished through the ordinary way of defrosting.
With these and other objects in view this invention consists in certainnovel features of construction, combination and arrangement of parts to be hereinafter more fully described and claimed.
For a complete understanding of my invention,
20 reference is to be had to the following description and accompanying drawing, in which Figure 1 is a fragmentary view showing my invention applied to a cooling or freezing unit of a refrigerator or similar device.
25 Figure 2 is a diagrammatical view illustrating the wiring diagram with my invention electrically connected thereto.
Referring in detail to the drawing, the numeral I indicates a cooling or freezing unit of the con- 30 ventional construction adapted for cooling 2. re-
frigerator or like device 2. To maintain the unit 8 at its highest point of efficiency it is necessary to defrost or remove from the unit the accumulation of snow ,or ice which is usually accom- 35 plished by rendering the device inoperative for a period of time to permit the snow and ice to melt fromsaid unit. Usually the defrosting operation requires a number of hours in which time the interior of the refrigerator or like device rises in temperature and to reduce the length of time to defrost the unit and to maintain the refrigerator at a comparatively low temperature my invention is employed which consists of a medium 3 to direct a blast of air onto the cooling or freeztively low temperature. The medium 3 is in the form of an electric motor 4 having secured to the armature shaft thereof a fan 5. The motor 4 may be'located within any desired place in the refrigerator so that the fan 5 when in operation 5 can direct air against the freezing or cooling unit I. Figure 2 shows the wiring 6 of an electrically actuated circuit for the unit I and which circuit is opened and closed by a temperature control "I. The temperature control is in the nature of a bellows-like member which is expanded or contracted by temperature conditions. The electric motor 4 is connected to the electric circuit 6 by conductors 8, 9 and Hi. The conductors 8 and 9 are separated by spaced contacts ll. Pivoted to the top of the temperature control I there is one end of a. lever l2, that is centrally pivoted to a supporting standard l3. The outer or free end of the lever has arranged therearound but insulated therefrom a U-shaped contact plate I4. Subjacent the contact plate l4 there is positioned a pair of spaced contacts l5 each connected to one of the pair'of main circuit wires 6 leading to the compressor motor for the unit I. Thecontact plate I4 is movable by the lever I2 to bridge the spaced contacts I l to direct current from the main circuit to the fan motor 8 and break the connection between the contacts 15 to shut off current from said main circuit to the compressor motor for unit I, or vice versa, in accordance with the expansion or contraction of the control element 1. Thus it will be seen that the electric motor 4 is set in operation when the motor of the refrigerant unit is stopped. This arrangement ormeans for directing air onto the cooling coil when the compressor is idle will materially aid in preventing the accumulation of frost and snow thereon thereby practically keeping the cooling unit in a defrosted condition over a long period of time.
Having described the invention, I claim:
The combination with a refrigerating system including its evaporator, compressor and driving motor therefor, of an independent motor driven fan for causing a flow of air through the refrigerator evaporator, and a thermostat controlling the refrigerating system compressor motor and fan driving motor for alternate operations JOHN A. SHRADER.