US2123059A

US2123059A - Refrigerating machine

Info

Publication number: US2123059A
Application number: US126211A
Authority: US
Inventors: Delbert F Newman
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1937-02-17
Filing date: 1937-02-17
Publication date: 1938-07-05
Anticipated expiration: 1955-07-05

Description

7 Inventor: Delbert F Newman.

His Attovngg.

D. F. NEWMAN REFRIGERATING MACHINE Filed Feb. 1'7, 1937 Fllll Jul -s, 1938.

Patented July 5,1938

REFRIGERATING MACHINE Delbert F. Newman, Schenectady, N. Y., asslgnor to General Electric Comp ny. a corporation of New York Application February 17, 1931, Serial No. 126,211

Claims.

high temperature of the evaporator during the initial portion of the "pull-down period, the

gaseous refrigerant drawn into the compressor and discharged into the condenser has a density considerably higher than normal, resulting in the compressor handling a much larger quantity of gaseous refrigerant than under normal operating conditions. The condenser is designed to condense only the gaseous refrigerant at the normal rate of discharge from the compressor, in order to provide an economical construction. The machine is, therefore, incapable of condensing the gaseous refrigerant at this increased rate of discharge from the compressor during the initial portion of this period, causing an abnormally high pressure to exist in the condenser. The compressor discharging against this abnormally high pressure head in the condenser may cause the motor driving the compressor to become overloaded or stalled.

It is an object of my invention to provide a compression type refrigerating machine having an arrangement for minimizing the increase in pressure above normal of the compressed refrigerant in the machine during the pull-down period of an evaporator associated with the machine from substantially an ambient temperature to an operating cooling temperature in order to prevent overloading of the compressor driving motor. I accomplish this by utilizing a refrigerant cooler interposed in the high pressure refrigerant circuit of the machine between the compressor and the condenser, the refrigerant cooler being arranged in good heat' exchange relationship with a heat absorbing body. Preferably, the refrigerant cooler is arranged in good heat exchange relationship with an hermetically sealed casing enclosing the compressor and its electric driving motor in order to provide a compact machine.

Further objects and advantages of my invention will become apparent as the following dewhich characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of my invention, reference may be had to the accompany drawing, in which Fig. 1 is a side elevation of a refrigerator cabinet provided with a refrigerating machine embodying my invention, portions of the cabinet and machine being broken away to show more clearly the arrangement; and Fig. 2 is an enlarged fragmentary sectional view of the enclosing casing for the compressor and its driving motor and the refrigerant cooler arranged in good heat exchange relationship therewith.

Referring to the drawing, in Fig. 1 I have shown a refrigerator cabinet l0 designed for domestic use which is provided with a heat insulated food storage compartment H in the upper portion thereof and a machinery compartment l2 arranged below the compartment H. An opening is formed in the front wall of the compartment H to afford access to the interior of the compartment and a heat insulated door I 3 is hinged adjacent the marginal edge of this opening. Openings are formed in both the front and rear walls of the machinery compartment l2 to afford ready access to the refrigerating machine arranged therein for purposes of inspection. A removable door I4 is arranged tocover the opening in the front wall of the ma.- chinery compartment l2 in order to give the refrigerator cabinet a finished appearance.

The refrigerating machine includes a cylindrical hermetically sealed casing l5 in which an electric driving motor l6 and a refrigerant compressor l1 are arranged, the compressor being secured to the top of the motor. Preferably, the casing I5 is constructed of sheet steel and has a relatively large mass. The motor and the compressor are resiliently mounted in the casing l5 on a series of equally spaced helical compression springs 18. The upper ends of the springs l8 are secured to the frame of the motor I 6 by a number of supporting feet l9 and the lower ends of the springs iii are secured to the bottom wall or end of the casing IS. The

springs l8 permit the motor and the compressor portion thereof which is recirculated to the moving parts of the motor and the compressor during the operation of the machine.

The casing I I is substantially vertically disposed and is secured to a supporting frame 20 adjacent the rear of the machinery compartment II. An air distributing hood 23 is secured to the supporting frame 23 adjacent the front of the machinery compartment l2 and is provided with an air inlet opening arranged in the front and bottom walls thereof for admitting cooling air into the machinery compartment below and adjacent the door II. The upper portion of the hood I! is securely braced by a strap 30 fastened to the casing II. An air outlet opening 3| is formed in the wall of the hood 2! adjacent the casing II and a fan 31 is arranged in the opening 3| in order to draw the cooling air through the hood. The fan 32 is operated by an electric motor 33 supported upon the casing I! by a brack et II. Within the hood 23 and adjacent the outlet opening 3l there is arranged an annular frustro-conical air deflecting baille 33 supported upon a series of studs 33. The cooling air drawn into the hood 23 by the fan 33 is distributed uniformly through the hood by the air deflecting baille 33 and is discharged through the outlet opening 3|. The baffle 33 also contributes toward quiet operation of the fan 33 by distributing the cooling air drawn through the hood 23 more uniformly adjacent the outlet opening 3 I.

During operation 01' the refrigerating machine illustrated, gaseous refrigerant is drawn into the compressor II from the casing 15 through an intake mufller 31 and is compressed and discharged into an exhaust mufller 38. the intake and exhaust mumers being arranged within the enclosing casing IS. The compressed gaseous refrigerant is conducted from the exhaust mumer 33 by a flexible conduit 39 into a conduit 40 arranged exteriorly of the casing." and sealed in an opening in the bottom of the casing ii. The conduit 30 communicates with a refrigerant cooler ll disposed in good heat exchange relationship with the lower portion of the casing II. This casing is formed of sheet steel and has a relatively large mass constituting a heat absorbing body. Preferably, the refrigerant cooler ll comprises a coil of copper pipe having a substantially half-round cross section, the flattened wall a of the coil being soldered to the periphery of the casing II as shown at llb in Fig. 2. The com pressed refrigerant, after passing through the cooler II. is conducted by a conduit 42 into the upper portion of a refrigerant condenser 43, the condenser 43 being arranged within the air distributing hood 23 adjacent the inlet opening in the front and bottom walls of the hood. The condenser 43 is arranged in an inclined position to facilitate the flow of the refrigerant liquefied therein in a downward direction and is secured in place upon a wall of the hood 23 by bolts 44. The compressed refrigerant is liquefied in the condenser 43 and flows from the lower portion thereof through a liquid conduit 45 into a suitable flow controlling float valve 43 arranged in the top of the cabinet, which regulates the quantity of liquid refrigerant supplied through a conduit 41 to a flooded type sheet metal evaporator 43. The evaporator 33 is positioned in the upper portion of the food storage compartment II and is suspended beneath the top wall thereof. The liquid refrigerant contained in the evaporator 33 is vaporized by the absorption of heat from articles contained in the compartment in which the evaporator is located and the vaporized refrigerant is collected in a cylindrical header 43 which is normally maintained about one-half full of liquid refrigerant The vaporized gaseous refrigerant accumulating in the upper portion of the header 2! above the level of the liquid refrigerant therein is conducted through a conduit ll into a cofl 5| arranged in good heat exchange relationship with a tubular extension on the flow controlling float valve 43 in order to cool the liquid refrigerant supplied to the evaporator ll. The gaseous refrigerant is then returned to the interior of the casing II through a suction conduit 32. It will be noted that the discharge end 52a of the suction conduit 62 is located above the level of the body of lubricant contained in the lower portion of the casing II. The gaseous refrigerant thus discharged into the casing II is again drawn into the compressor l1 through the intake muiller 31 and the cycle above described is repeated until the food storage compartment II in which the evaporator 40 is located is cooled to the desired temperature. Preferably. the liquid conduit 43 and the suction conduit 52 are arranged in a flexible enclosing conduit 53 extending from the machinery compartment I2 up the rear wall of the refrigerator cabinet to the upper portion of the cabinet II.

The supporting arrangement for the enclosing casing ll and the air distributing hood 2! permits the refrigerating machine to be readily placed into and removed from the machinery compartment I! in assembled relation without disturbing the evaporator 43 in the food storage compartment ll.

During operation of the refrigerating machine, cooling air is drawn into the air distributing hood 29 by the fan 32 through the inlet opening in the front and bottom walls thereof below and adjacent the door ll closing the opening in the front wall of the machinery compartment. The cooling air then flows uniformly through the refrigerant condenser 43 due to the arrangement of the air deflecting baflle 35 and is discharged through the outlet opening 3| about the casing II and the refrigerant cooler II. The cooling air flows about the casing and refrigerant cooler and out of the machinery compartment through the opening in the rear wall of the compartment. Preferably, the fan driving motor 33 is arranged in a circuit with the compressor driving motor i3 and a suitable thermal control device which is operable to maintain any given average temperature over a predetermined range of temperatures within the food storage compartment ll, so that these motors are started and stopped simultaneously.

During the initial portion of the pull-down" period the gaseous refrigerant drawn into the compressor I! from the enclosing casing I! has a density considerably higher than normal due to the relatively high temperature of the evaporator 48. Consequently, the compressor handles a much larger quantity of gaseous refrigerant during the initial portion of the pull-down" period than under normal operating conditions. The condenser 43 is designed to condense only the gaseous refrigerant at the normal rate of discharge from the compressor in order to provide an economical construction. Thus, the machine is incapable of condensing the gaseous refrigerant at this increased rate of discharge from the compressor during the initial portion of this period. It is apparent that if the compressor I! were arranged to discharge directly into the condenser 43, an abnormally high pressure would be built up in the condenser 43 during the initial portion of the pull-down period and that .head would overload the compressor driving motor ii. In fact, the driving motor i6 might become so heavily overloaded that it would become stalled.

In order to minimize abnormally high pressures in the refrigerating machine during the initial portion of the pull-down" period, the refrigerant cooler 4i is arranged in good heat exchange relationship with the casing I5 and is interposed in the high pressure circuit of the refrigerating machine between the compressor l1 and the condenser 43. All of the elements of the refrigerating machine including the casing I! have a tempera-- ture corresponding to ambient at the beginning of the pull-down period as previously pointed out, which temperature is considerably lower than the temperature of the compressed gaseous refrigerant discharged from the compressor. The casing I 5 being constructed of sheet steel and having a relatively large mass, thus has a considerable capacity for absorbing heat from the refrigerant cooler 4i and the compressed gaseous refrigerant passing through the cooler during the initial portion of the pull-down"period. The cooling action of the refrigerant cooler 4i upon the compressed gaseous refrigerant passing therethrough and entering the condenser 43 reduces the amount of superheat of the compressed gaseous refrigerant and remains the samewhen it reaches the condenser 43, permitting the compressed gaseous refrigerant to be readily liquefied in the condenser at a relatively low pressure and to be supplied to the evaporator 48. It will be noted that the resilient mounting of the compressor driving motor l6 including the helical compression springs l8 spaces the motor within the enclosing casing i5 away from the side walls thereof, which spacing retards the flow of heat from the motor to the casing. This mounting arrangement allows the refrigerant cooler 4| to utilize substantially all of the heat absorbing capacity of the casing l5 to cool thecompressed gaseous refrigerant during the initial portion of the pull-down period. Consequently, the existence of abnormally high pressures in the refrigerating machine are minimized.

The temperature of the casing l5 gradually rises upon operation of the machine during the pull-down period due to the absorption of heat from the refrigerant cooler 41. The temperature of the casing approaches the temperature of the refrigerant cooler, at which point no precooling of the compressed gaseous refrigerant is effected. In a similar manner, the density of the gaseous refrigerant drawn into the compressor I! from the casing l5 gradually decreases during the operation of the machine due to the lowering of the temperature of the evaporator 48, causing a corresponding gradual decrease in the rate of discharge of the gaseous refrigerant from the compressor l1. Thus, the rate of discharge of the gaseous refrigerant from the compressor approaches normal, at which point no pre-cooling of the compressed gaseous refrigerant is required by the condenser. From the above description of operation of the refrigerating machine, it will be understood that pre-cooling of the compressed gaseous refrigerant is required only during the initial portion of the pull-down period to avoid abnormally high pressures in the refrigerating machine, and that the refrigerant cooler is operable to effect pre-cooling of the compressed gaseous refrigerant during this portion of the be understood that no pre-cooling of the compressed gaseous refrigerant is required during" the normal operation of the refrigerating machine as the condenser is capable of condensing the compressed gaseous refrigerant at the normal rate of discharge from the compressor, and that the refrigerant cooler effects no appreciable pre-cooling of the gaseous refrigerant during normal operation of the refrigerating machine.

It will thus be seen that I have provided a compression type refrigerating machine having a compact arrangement for minimizing the increase in pressure above normal-of the compressed refrigerant in the machine during the pull-down period of an evaporator associated with the machine from substantially an ambient temperature to an operating cooling temperature.

While I have shown a particular embodiment of my invention in connection with a refrigerating machine designed for domestic use, I do not desire my invention to be limited to the particular construction shown and described, and I intend in the appended claims to cover all modifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A refrigerating machine including a refrigerant compressor, means for driving said compressor, means including a condenser communicating with said compressor for liquefying the compressed refrigerant delivered thereto, an

evaporator supplied with liquid refrigerant from said condenser, a heat absorbing body, and means including a refrigerant cooler connected between said compressor and said condenser and arranged in good heat exchange relationship with said heat absorbing body for minimizing the increase in pressure above normal of the compressed refrigerant in the refrigerating machine during the pull-down period of said evaporator from substantially an ambient temperature to an operating cooling temperature, said last-mentioned means utilizing the heat absorbing capacity of said body during the initial portion of the pulldown" period for reducing the amount of superheat of the compressed refrigerant delivered to said condenser.

2. A refrigerating machine including a refrigerant compressor, a motor for driving said compressor, a casing enclosing said compressor and said motor, means including a condenser communicating withsaid compressor for liquefying the compressed refrigerant delivered thereto, an evaporator supplied with liquid refrigerant from said condenser, and means including a refrigerant cooler connected between said compressor and said condenser and arranged in good heat exchange relationship with said casing for minimizing the increase in pressure above normal of the'compressed refrigerant in the refrigerating machine during the pull-down period of said evaporator from substantially-an ambient temperature to an operating cooling temperature, said last-mentioned means utilizing the heat absorbing capacity of said casing during the initial portion of the pull-down period for reducing the amount of superheat of the compressed refrigerant delivered to said condenser.

3. A refrigerating machine including a refrigerant compressor, a motor for driving said compressor, a casing enclosing said compressor and said motor, means including a condenser communicating with said compressor for liquefying the compressed refrigerant delivered thereto. an evaporator supplied with liquid refrigerant from said condenser. and means including a refrigerant cooler connected between said compressor and said condenser and arranged about said casing in good heat exchange relationship therewith for preventing overloading oi said driving motor during the "pull-down period" of said evaporator from substantially an ambient temperature to an operative cooling temperature, said last-mentioned means utilising the heat ahsorhing capacity of said casing during the initial portion of the "pull-down" period for reducing the amount of superheat oi the compressed refrigerant delivered to said condenser.

4. A refrigerating machine including a refrigerant compressor. a motor for driving said compressor, a casing enclosing said compressor and said motor, means including a condenser communicating with said compressor for liquefying the compressed refrigerant delivered thereto, an evaporator supplied with liquid refrigerant from said condenser, and means including a refrigerant cooler coil connected between said compressor and said condenser and arranged about said casing in good heat exchange relationship therewith for minimizing the increase in pressure above normal of the compressed refrigerant in the refrigerating machine during the pulldown" period of said evaporator from substantially an ambient temperature to an operative cooling temperature, said last-mentioned means utilising the heat absorbing capacity of said casing during the initial portion of the "pulldown period for reducing the amount of superheat of the compressed refrigerant delivered to said condenser.

5. A refrigerating machine including a refrigerant compressor, a motor for driving said compressor. a casing enclosing said compressor and said motor, means including a condenser communicating with said compressor for liquefying the compressed refrigerant delivered thereto, an evaporator supplied with liquid refrigerant from said condenser, means including a refrigerant cooler connected between said compressor and said condenser and arranged in good heat exchange relationship with said casing for minimizing the increase in pressure above normal of the compressedrefrigerant in the refrigerating machine during the pull-down" period of said evaporator from substantially an ambient temperature to an operative cooling temperature, said last-mentioned means utilizing the heat absorbing capacity of said casing during the initial portion of the pull-down" period for reducing the amount of superheat of the compressed refrigerant delivered to said condenser, and means for directing a current of cooling air over said condenser and thence over said cooler and said casing;

DELBERT F. NEWMAN.