US 2632304 A
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Description (OCR text may contain errors)
March 24, 1953 c. WHITE, JR 2,632,304
OIL DEFROSTING UNIT I Filed Aug. 1, 1949 Inventor lrby 6'. While, Jr
By MM 8 Patented Mar. 24, 1953 UNITED STATES PATENT OFFICE 2 Claims.
This invention relates to novel and useful improvements in refrigeration apparatus and the operation thereof.
An object of this invention is to improve the operation of conventional or non-conventional refrigeration apparatus by storing, heating and circulating a non-aqueous liquid or other liquid which has a strong tendency to remain in the liquid state throughout a large range of temperature change to accomplish the defrosting of the evaporator in the conventional or non-conventional apparatus.
Another object of this invention is to improve the mode of operation of refrigeration apparatus and more specifically the defrost cycle thereof regardless of the type of motivation used for the defrosting medium in the apparatus by introducing the defrost medium throughout the pertinent parts of the structure including the cooling unit in the liquid state and retaining it in the liquid state at the initial stages, during the middle stages and at the final stage of the defrost cycle of operation.
Ancillary objects and features will become apparent in following the description of the preferred illustration setting environment of the invention in the accompanying drawing wherein:
Figure 1 is a partial schematic and partial sectional view showing a structural arrangement of a refrigeration apparatus.
Figure 2 shows part of the electrical system.
The illustrated structure include a number of conventional elements. There is a cooling or evaporator unit generally indicated at H! receiving refrigerant through a feed line l4 having an expansion valve 12 operatively connected therewith. The valve i2 is controlled by the feeler it which has a capillary actuating connection I8 for the valve l2. The feeler bulb I6 is firmly connected with the line 20. A solenoid valve 22 is interposed in a conduit or line 24 which is connected with the expansion valve [2 at one end and extends through the heat exchanger 26 to connect with a refrigerant receiver or storage reservoir 93 at the other end. The suction line 28 is operatively connected with the heat exchanger and with the closed chamber Or tank 39, the tank 39 being insulated from the surrounding atmosphere by the insulation 32 therearound, as is known in the art.
A compressor 54 operated by a motor 56 receives refrigerant gas from the chamber 30 through a suction line 62" and delivers compressed refrigerant through the condenser line 64 including the condenser 61 to the receiver 98. The condenser line 64 is provided with a manual service valve and suction line 82 is provided with a service valve 65.
The container 30 also stores the lubricating oil for the compressor 54 and oil flows from the con tainer 30 into the casing of a compressor 54 through an oil line 6-0 having a service valve 68. A pressure equalizing line 58 above the oil level in the container 30 admits gas into the casing of the compressor 54 so that the oil level in the casing of the compressor 54 will correspond to the oil level in the container 30. A service valve 10 is placed in the equalizer line 58.
With the exception of the solenoid valve 22 the above described refrigerator system is conventional and forms the basic system with which the present invention is combined.
The defrosting operation utilizes a line 34 extending into the cooler 34, and having a coil 38 disposed in the drip pan 39 and connecting through a check valve 42 and conduit 40 to the supply line H for the evaporator. The check valve 42 allows flow in one direction through line 34 and inhibits return flow into the line 34 from the line l4. At the opposite end of the line 34 there is provided a connection with a circulating pump 45 and a manually operatively service valve 48 is connected in the line 34 upstream of the flow therein during the defrost cycle of operation. A length of tubing or pipe 50 is connected to the inlet side of the circulating pump and the interior of the tank 30, a service valve 52 being positioned in line 50.
The typical electrical system involved in the illustration includes supply conductors 12 connected to a timer l4 and supplied by a suitable source of electrical power (unshown), various electrical conductors and other mechanism. Noting first the electrical timer (4, there are two electrical conductors 16 extending therefrom and terminating in the motor controller 18. Two other electrical conductors extend from the electrical line and terminate in the circulating pump 46. Electrical conductors 82 extend from the timer and connect operatively with the fan or blower generally indicated at 86. This fan is disposed behind the cooling unit to serve its conventional function. The final conductor 88 extends from the timer and terminate in electrical connection with the solenoid valve 22.
Suitably connected for operation in the tank 30 is a two-stage thermostat 90 and a first heater element 92 together with a second heater element 94. A switch I00 connects the supply 12 to conductors I02 which in turn are connected to the time 14, a branch circuit I04 supplies energy to the heaters 92 and 94 with the thermostat switch 90 selectively connecting the heaters across the conductors I04.
The operation of the described structure is typical of a substantially conventional refrigeration apparatus. Now, the prior art is replete with structure arranged in various mannerisms which operate for the purpose of cooling the unit l and then defrosting the same at timed intervals or responsive to other outside stimuli. It is in the defrost cycle of operation that my invention resides. Various patents show different types of defrosting operations during the defrost cycle however, in all defrost cycles of operation there is the so-called hot gas operation, a typical one being the steps of taking hot gas from the compressor through a tank to store heat in an organic solution during the normal operation of the system which is to be later used in the reversal of the cycle. In the majority of instances there is a, change of state necessary for the successful operation in the defrost cycle. This change of state referred to, is the passing of the heating medium from the gas to the liquid state or from the liquid to the gaseous. In contrast, there is herein a system of defrosting refrigerating cooling coils by using a quantity of a particular class or group of liquids which have a strong tendency to remain in the liquid state throughout a large range of temperature change. The liquid may or may not be aqueous and is preferably nonaqueous. Ordinary refrigeration oil of the same type as employed in a refrigerating system for lubricating the compressor is preferable.
The oil is heated by means of the electrical elements 92 and 94 which are thermostatically controlled (by a thermostat 9D) and mounted in the manner disclosed in the illustration. Preferably, the first heating section has the capacity necessary to recover heat losses from the oil due to the insulating casing, oil returning through the cooling coils in the normal refrigerating cycle and the suction gas passed through the oil storage tank.
The second electrical heater section has the capacity necessary to recover the heat losses in the process of removing frost and ice from the cooling coil or coils and of course, the drip pan 39. Thethermostat actuates the electric heater in two stages of operation, from the normal operating temperature of approximately 160 F., the first heater stage being energized when the temperature of the oil is reduced 3 F. and the second heater section becomes energized with a further reduction of 10 F.
At a predetermined time the electrical timer 14 which is in reality a defrosting controller is rendered operative so that the compressor motor will stop and the liquid line solenoid 22 will close, the fan 86 will be rendered inoperative and the circulating oil pump 46 will be rendered operative. The pump 46 takes heated oil from the closed chamber 30 and pumps it through the line 34, the coil 38, check valve 42 and conduit 40 into the coils of the cooling unit I9. It passes through the check valve 42 in this operation and also throughthe suction line 28 after passage through the heat exchanger 25 for ultimate disposition in the closed chamber 30. This cycle of operation is the defrost cycle, it being noted that the oil is ultimately re-deposited in the tank 30 so that it is reheated and continues in the cycle until sufficient heat has been transferred from the heat source to melt the frost and ice on the cooling coils and drip pan whereby efficiency of the unit is maintained at the engineering level.
After the coils and drip pan have been defrosted the timer 14 renders the circulating pump 46 inoperative, opens the liquid line solenoid 22, makes the fan 86 operative and places the compressor motor under an electrical load so that the refrigerating system is again in normal operation.
Having described the claimed as new is:
1. A defrosting refrigerating system including, a refrigerant compressor, a receiver for condensed refrigerant, a condenser tube connected between said compressor and said receiver, an evaporator coil, a refrigerant conduit connected between said receiver and the inlet terminal of said evaporator coil, temperature responsive valve means in said refrigerant conduit for admitting refrigerant from said receiver to the inlet terminal of said evaporator coil, a return conduit from the outlet of said evaporating coil to said compressor, a chamber in said return conduit, a quantity of compressor lubricant oil in said chamber, an oil conduit from said chamber to the inlet terminal of said evaporating coil, a check valve in said oil conduit to prevent reverse flow of refrigerant or oil through said oil conduit to said container, a solenoid valve in said refrigerant conduit, a pump in said oil conduit, electrical control means operative to periodically close said solenoid valve and render such compressor inoperative, and to render said pump operative to pump said oil into said evaporating coil, said 011 passing through said evaporating coil and said return conduit to said chamber, thermostatically controlled heating means for maintaining the oil in said chamber at .a predetermined temperature.
2. A defrosting refrigeration apparatus including a closed refrigerating system including a compressor, a refrigerating coil, connections between said compressor and said coil, said connections including a condenser tube, a receiver and an expansion valve, suction line means, connecting said refrigerator coil with said compressor, a chamber in said suction line, said chamber providing oil storage space, said compressor pumping refrigerant to said refrigerating coil, a separate conduit from said chamber to said refrigerating coil, a pump in said separate conduit, a check valve in said separate conduit, a solenoid valve in series with said expansion valve, a time invention, what is responsive controller to periodically close said solenoid valve, deenergize said compressor and start said pump to circulate oil from said chamber through said refrigeration coil, means for heating the oil in said chamber.
IRBY C. WHITE, JR.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 1,819,510 Hebeler Aug. 18, 1931 2,228,364 Phillip Jan. 14, 1941 2,243,466 Kucher May 27, 1941 2,301,656 Hirche Nov. 10, 1942 2,451,682 Lund Oct. 19, 1948 2,452,102 Cocanour Oct. 26, 1948' 2,459,173 McCloy Jan. 18, 1949 2,524,568 Kritzer Oct. 3, 1950 2,526,032 La Porte Oct. 17, 1950 2,551,163 Rickert et al May 1, 1951