US3022639A - Built-in refrigeration apparatus with defrost controls - Google Patents

Description

Feb. 27, 1962 c. E. BROWN ErAL BUILT-IN REFRIGERATION APPARATUS WITH DEFROST CONTROLS 5 Sheets-Sheet 1 Filed Sept. 18, 1959 INVENTORS CARL E. BROWN FRANK P. CROTSER BY ATTORNE S Fe 27, 1 c. E. BROWN EI'AL 3,022,639

BUILT-IN REFRIGERATION APPARATUS WITH DEFROST CONTROLS Filed Sept. 18, 1959 5 Sheets-Sheet 2 CARL E. BROWN RANK P. CROTSER BY ,F

WC ATTOR; YS

Feb. 27, 1962 C. E. BROWN EI'AL BUILT-IN REFRIGERATION APPARATUS WITH DEFROST CONTROLS Filed Sept. 18, 1959 5 SheetsSheet 3 FRANK P. CROTSER ATTORN YS 7 l Feb. 27, 1962 c. E. BROWN ETAL BUILT-IN REFRIGERATION APPARATUS WITH DEFROST CONTROLS Filed Sept. 18. 1959 5 Sheets-Sheet 4 INVENTORS CARL E. BROWN FRANK P. CROTSER BY WKMM? ATTORNEY Feb. 27, 1962 BUILT-IN REFRIGERATION APPARATUS WITH DEFROST CONTROLS Filed Sept. 18, 1959 c. E. BROWN ETAL 3,022,639

5 Sheets-Sheet 5 CON 234 223 COMP. 2 MOTOR TIMER {MOTOR .1 2 22! I 222 211 2Q X N210; 032331 212 202 53/ mmvrozzs CARL E. BROWN FRANK P. CROTSER AITORN United States Patent r, V 3 2 39 BUILTJN REFRIGERATION APPARATUS 7 WITH DEFROST CGNIROLS Cari E. Brown and Frank P. Crotser, Adrian, Mieli as signers to Revco, Inc., Deerfield, Mich, a corporation of Michigan Filed Sept. 18, 1959, Ser. No. 840,977 6 Claims. (Cl. 62-155) ment so that it may function as a part of the cabinet and 9 table working space while presenting the most pleasing appearance to the eye. It has therefore been increasingly the aim of manufacturers of kitchen equipment to provide units that are completely self-contained that will slip into a standard designated cabinet space, and will coordinate with standard heights of cabinets and other kitchen apparatus, all the while developing the most efficient cooperation of parts needed to perform the function desired by the kitchen unit.

The housewife of previous years was satisfied with bulky refrigerating apparatus that occupied quite a bit of space and which generally only had a small subdivided portion of the refrigerator which functioned as 2. below freezing compartment. With the advent of the frozen food market freezing space needs in the home increased tremendously and brought about the introduction of household freezers as separate items from the ordinary household refrigerator. Today, manufacturers have developed to a high degree more efficient and more aesthetic freezing units to be utilized as the built-ins referred to above requiring less care and less time by the owner. Therefore, inconveniences formerly endured by the housewife have now become intolerable and the unit on the market that has the least number of such in conveniences is the best competitive model and best fulfills the utility requirement of the housewife.

Accordingly, it is an object of this invention to provide improved refrigerating apparatus.

It is another object of this invention to provide an improved freezing unit in which the construction and allocation of the cooperative necessary refrigerating itern results in a highly efficient unit.

It is still another object of this invention to provide a freezer unit which may be utilized with kitchen cabinets as an extension of the working space thereon and which will not need the ordinary air circulation spaces behind or around the unit so that the freezer unit may be installed flush with the wall and with the perpendicular sides of cabinets or apparatus on-either side of the freezer unit.

A further object of this invention is to provide a novel arrangement of a heat absorber means and an air circulation means within a storage compartment of the refrigeration apparatus which is more efficient and which confines. frosting to hidden area where the frost may be removed automatically.

A further object of this invention is to provide a freezing unit which will have a storage compartment that will not have to periodically be shut down or unloaded in order to scrape or otherwise remove frost from the walls of the compartment or the foodstuffs stored therein.

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It is a further object of this invention to provide a built-in unit which utilizes most efficiently the space allocated in a condenser or general apparaltuscompartment for the operation of the freezing unit.

A still further object of this invention is to provide a novel refrigeration system which may be'utilized with the built-in unit disclosed herein.

In accordance with the above objects there is provided refrigeration or freezing apparatus comprising a thermally insulated cabinet having a storage compartment. Heat absorber means, such as an evaporator coil, are disposed across and adjacent to a ceihng of the storage compartment. Shelf means are provided for supporting the evaporator coil adjacent the ceiling. The shelf means may include an insulation layer supporting a drip pan, which in turn, supports the evaporator and associated assembly. Within the storage compartment there is false wall means, most advantageously disposed along a. rear Wall of the cabinet, which false Wall means cooperates with the support means supporting the evaporator to form an air duct across the ceiling and one Wall of the conipartmerit. An evaporator fan is adapted to circulate air into this air duct adjacent a door Wall of the compartment and discharge the air through an exhaust port in the false wall. The evaporator fan is advantageously driven by a shaft of a motor which is mounted on the exterior of said cabinet in a recess provided therefor so that the cabinet may fit flush against a wall when installed. The exhaust port is advantageously located in the lower portion of the false wall and is also advantageously located to supply cold air directly from the air stream of the fan blades to a portion of the compartment in which ice cube trays are located to freeze the ice more quickly.

The refrigeration system means adapted to supply refrigerant to the evaporator above includes a defrost coil and a compressor. The defrost coil is located in intimate heat exchange relationship with the evaporator coil within the storage compartment. The defrost coil has an inlet which is coupled through a valve means to a high pressure side of the compressor. A defrost coil return conduit is coupled to'the low pressure side of the com- 'ru'esstuthrough a restriction tube. A portion of this defrost coil return conduit is placed in heat exchange relationship with a heat source which may preferably be a lubricant and/or coolant in the compressor. This is most advantageously accomplished by utilizing a cornpressor which already has built therein an oil-cooler loop which Was heretofore utilized for a different function.

As stated above the means supporting the evaporator coil includes a drip pan which extends under the entire area of the evaporator. A drain tube means connects the drip pan with an exterior drain pan Where the excess water is evaporated. The portion of the drain tube which is located Within the storage compartment, and thus exposed to below freezing temperatures, is held at a temperature above freezing during a defrost interval or operation by being disposed in heat exchange relationship with a hot defrost coil inlet and/ or return conduit which keeps the drippings or condensate melted during the defrost operation. The defrost coil inlet, the defrost return conduit and the drain tube are disposed behind the false wall.

compressor. A compressor or condenser fan is provided in the apparatus compartment which circulates air in the apparatus compartment so that the condenser and the compressor arecooled. The heating of the air circulated by said condenser fan by the condenser and compressor is utilized to help evaporate the moisture accumulated in the drainpan. In the built-in shown, the air inlet and the air exhaust for the apparatus compartment are arranged out of sight in the toe space in the lower front of the unit. The apparatus compartment is also provided with .means, shown hereinafter as a baflle, to direct a portion of the air stream from the condenser fan across the evaporator fan motor which is located in a recess adjacent the apparatus compartment.

The refrigeration system comprises the portions mentioned hereinbefore and includes a novel accumulator particularly adapted for use in the space-saving arrangernent disclosed herein. Thermostatic means controlling the refrigeration cycles of the refrigeration system are provided which has a heat sensitive element advantageously disposed in the air stream of the air duct formed by the shelf and false wall. That is, the refrigeration heatsensitive element is most advantageously disposed in the path of the air stream in the air duct after said air stream,

has passed over and been cooledby said evaporator coil. A defrost thermostatic control means may-be attached in intimate heat exchange relationship with the drip pan disposed beneath the evaporator coil or with the evaporator coil itself. It would preferably be connected to the drip pan since this would insure that moisture accumulated in the drip pan during the defrost cycle, will remain in a liquid form until it is drained away before the next refrigeration cycle starts in the evaporator.

Other objects, features, and advantages of the inven-v tion will become apparent when the following description is taken in conjunction with the accompanying drawings, in which: j

FIG. I is a cross-sectional side viewof the built-in unit embodying the teachings of this invention;

FIG. H is a rearview of the built-in unit with sections broken away to disclose the disposition of the various units therein; I

FIG. III is a fragmentary front view. of the built-in unit with the door wall removed;

FIG. IV is a sectional view of the apparatus compartment taken at lines IVIV of FIG. III;

FIG. V is a plan view on an enlarged scale of the evaporator and, defrost coils utilized in this invention shown connected to an accumulator shell and a portion of a suction pipe and capillary tube in a combination as utilized in this invention; FIG. VI is an elevational view, with part in section, showing the apparatus illustrated in FIG. V;

FIG. VII is a cross-sectional view of the accumulator utilized in this invention; 7 'FIG. VIII is a schematic plan of a refrigeration system utilized herein;

FIG. IX is a cross-sectional view showing a possible method of heat exchange. relationship between a drain tube and a hot gas defrost line as utilized herein; and

FIG. X is a schematic diagram of a control circuit'for the apparatus of this invention. a

Referring to FIGS. I through IV there is illustrated a thermally insulated cabinet designated generally at 10 having a storage compartment 11 formed therein. The storage compartment has a rear'wall 12, a ceiling 13, a

front door wall 14, and insulated side walls 15 and 16.

A shelf meansft) is attached to the side walls 15 and 16.

V 106 adjacent to the ceiling 13. The shelf means cooperates with a false Wall 23, shown'here as extending down the rear wall 12 of the storage compartment 11 to form an air duct. A blower or evaporator fan 24 which is driven by a shaft 25 of a motor 26 is disposed in an exhaust port 27 located in the lower portion of the rear wall 23. The fan blade 24 energized by the motor26. exhausts air through the port 27 from the airduct from material.

drawn into'the air duct over the front of the'shelf 26} which is adjacent the front door wall 14. A baffle 28 is attached to the ceiling 13 of the storage compartment 11 and conceals from view a light 29, which may be operated by a switch attached to the door, and also conceals from view the evaporator coils 1G6 upon which frost may accumulate. V V

As best seen in FIGS. I and II an outer liner 30 encloses the insulation 31 which is contained between the storage compartment walls and ceiling and the outer lining 30. The outer lining may be extended as shown at 31, 32,

33 and 34 to completely enclose the apparatus or co'ndenser compartment 17 on the sides, at the rear and at the bottom. The wall sections 31 through 34 may, of course, be made from individual sections as long as the apparatus compartment 17 is formed to be comparatively air tight except for the air admission space at the toe space 35. As is best shown in FIGS. I and II a recess 36 is formed on the exterior of the cabinet 'so that the evaporator fan motor 26 may be set in and allow the unit to fit flush against the rear wall, Although not shown a shell condenser may be added on the outside of the outer liner 30 if desired. The finishing top material for the unit is not shown since it may be desired to provide it with a top with a porcelain finish, a tile finish or an extensionof the normal cabinet top which may be of any The arrangement of the apparatus in the condenser or the apparatus compartment ismost clearly shown in FIGS; II and IV. A condenser 105 is disposed at an angle as best shown in FIGS. I and II so that the entire air stream entering from the toe space 35 will-pass over the condenser 105 and cool its contents. A condenser fan designated generally at 13% pulls theair stream in on the right side of theme space-as is'shown in FIG. IV upon the right side of the baffle 131 which dividesthe apparatus compartment into two parts. The baffle 131 has a port 132 formed therein in which the fan blade of the condenser fan 130 is disposed. A second'baflie 133 as best seen in FIG. II is disposed to collect a portion of the air stream from the condenser fan 130 and direct it into the recess 36 containing the evaporator fan motor 26 to thereby cool it. Thecompressor designated generally at 109'is situated in the air stream of the condenser fan 130 and is cooled thereby. A drain pan 140 is located in the apparatus compartment on the left side of the baffle 131 as shown in'the view of FIG. IV. The heat contributed by the condenser 105, the evaporator fan motor 26, and the compressor 16% is now in the air stream being circulated by the condenser fan 130 and is utilized to help evaporate the moisture in the drain pan 140. As will be explained hereinafter the drain pan 140 is connected through a drain tube to the'drip pan below the evaporator 1%.

As may be best seen in FIGS. V, VI and VII, the refrigeration system comprises the particular parts and components shown in those views and their connections are schematically illustrated in FIG. VIII. The compressor unit is designated generally at and comprises a refrigerant compressor 101, which may be of any desired commercially available type, which is driven by a motor 102. phase on its low pressure side through suction line inlet 103 and discharges it at high pressure still in the gaseous phase'through its high pressure side outlet 104. From there the refrigerant passes into a condenser 105 where itcools under pressure and liquefies. i The condenser 1G5 as well as the evaporator coil. 105 are shown schematically as made of piping but they they may, of course, be made of sheet metal or any desired construction. V

Refrigerant in the liquid phase is conducted' from the condenser 105 to the evaporator 106 by a first capillary tube 107 which enters the suction pipe 108 at' a'fitting accuse I: U 109 and lies Within the suction pipe 108. The capillary tube 107 lies within the suction pipe 108 along a sufficient portion of the lengths of the two tubes to transfer heat from the liquid refrigerant within the capillary tube to the gaseous refrigerant that is being pumped through the suction pipe 103 thus cooling the liquid within the restrictor tube 107 and warming the gas that is being returned to the compressor through the suction line 108 thereby improving the efficiency of the system. The discharge end 110 of the capillary tube 107 extends into the intake end 111 of the evaporator coil 106 and the liquid from the capillary or restrictor tube 107 is substantially completely evaporated into gas as it passes through the evaporator coil 106.

After passing through the evaporator coil 106 the refrigerant in the gaseous phase with such residual liquid as may remain therein passes through a pipe 112 and a port 113 into the top of the accumulator shell 114. The suction line 108 with the restrictor tube 107 enclosed therein enters the accumulator shell 114 through a coupling 115 at one end of the accumulator shell, and extends entirely through the shell 114 protruding from a similar coupling 116 upon the other end of the shell. The portion of the suction line 108 that lies within the shell 114 thus extends from end to end in the upper portion of the shell as best seen in the cross-sectional view of the accumulator shown in FIG. VII. Extending along the top of the portion of the suction line 108 that lies within the upper part of the shell 114 is a series of perforations through which gaseous refrigerant is drawn into the suction line 108. In accumulators of the prior art having ports into which suction pipes opened, liquid refrigerant is liable to surge into the open ends of the suction lines or pipes when agitation of the refrigerant occurs because of abrupt changes in pressure or for other reasons. With the suction line constructed and arranged as shown in the drawings the only communication between the interior of the shell 114 and the interior of the suction line 108 is the series of perforations 117 at the top of the suction line 108 which lie closely beneath the ceiling of the accumulator shell or chamber. Such surging of liquid rcfrigerant into the suction line as hereinbefore described cannot now occur.

Exteriorly of the coupling 116 the terminal section of the suction line 118 is crimped or otherwise sealed, preferably at a plurality of places 118 around the capillary tube or restrictor line 107 to form a substantially fluidtight seal and the end of the suction line 108 is soldered 6 loop, commonly called an oil-cooler loop, which previously was used to cool the compressor when a fan was not used for fan cooling of the compressor. The heat exchange relationship illustrated herein is now utilized for defrost purposes. Assume that the solenoid valve 122 has been opened while the compressor is running thereby directing hot gas in heat exchange relationship with the accumulator shell 114 to help evaporate excess refrigerant in the shell, and to the hot gas defrost coil 123. From the defrost coil 123 the hot gas continues through the return conduit 124 into the oil-cooler loop 125. The heat or otherwise connected with a fluid-tight joint to the inlet 7 end of the evaporator coil 106, which preferably also is of aluminum, and into which the discharge end 110 of the capillary tube 107 projects. This construction eliminates any possibility of leakage of refrigerant into the air of the room. Any slight leakage of the refrigerant at the places 118 where the suction pipe is crimped around the capillary or suction tube is of no significance since the refrigerant will leak only to the evaporator to the accumulator or vice versa, the evaporator and the accumulator already being openly connected with each other as described.

At the high pressure outlet 104 of the compressor 101 a T section 120 is placed in the hot gas line 104 leading from the compresor. A hot gas inlet line 121 connects the hot gas conduit 104 to the defrost coil 123 which is associated in heat exchange relationship with the evaporator coil 106. The valve 122 may be a solenoid operated valve which will be energized in accordance with the control circuit to be discussed hereinafter. The defrost coil 123 is connected through a defrost or hot gas return conduit 124 and through a second restrictor or capillary tube 126, to the suction line 108. A portion 125 of the return conduit 124 is disposed in heat exchange relationship with the lubricant and/or coolant of the compressor unit 100.

Commercially available compressor units have such a exchange taking place between the oil or coolant of the compressor raises the temperature of the refrigerant in the oil-cooler loop and correspondingly raises the pressure. This causes more fio'w through the restn'ctor line 126 because of the pressure dilferential between the oil-cooler loop and the suction line or low pressure inlet side 103 of the compressor unit 100. Therefore, a faster de-, frost time is obtained because more hot gas is moved. through the defrost 'coil 123 during a given defrost interval because of the heat added to the return conduit at the oil-cooler loop 125 It is to be noted that other heat sources may be utilized to apply heat to the portion 125 of the return conduit 124 in order to decrease the defrost time.

I As ay be best seen in FIG. I and FIG. IX the hot gas defrost inlet 121 and/or the hot gas return conduit 124 may bedisposed in heat exchange relationship with the drain tube 50 in order to insure that the accumulated moisture from the melting frost and ice on the evaporator" coil 106 will drain properly through the drain tube 50 to the drain pan 140. The hot gas' inlet line 121 may be held in heat exchange relationship with the lower portion of the accumulator shell 114 by theuse of flanges 151 soldered or otherwise attachedt-o the sides of the accumulator shell 114. As shown in FIG. lX both the hot gas inlet 121 and the. hot gas return conduit 124 may be placed in heat exchange relationship with the drain tube 50.

In operation the apparatus shown herein operatively circulates refrigerant through the condenser 105, restrictor 107' and evaporator 106 to refrigerate the compartment 11. The evaporator fan motor 26 may be connected to run at all times except during defrosting. If so, air is constantly being circulated in through the inlet past the evaporator coil and past a heat sensitive element 54 in the duct formed by the cooperation of the shelf means 20 and a false wall means 23. However, heat losses may be kept at a minimum if the fan 26 runs only during the refrigerating cycle. The heat sensitive element 54 may be best seen in FIGS. I and II and is part of a thermostatic control unit which controls the operation and running of the compressor to keep the temperature within the compartment within a predetermined low range. The disposition of the heat sensitive element 54 in the air path to the duct after the evaporator 106 enables the freezing compartment to be kept within a predetermined tempera ture range which will keep the items stored therein frozen. However, when the door is opened the warm air that enters the compartment will pass over the evaporator coils first, will be cooled, and will not cause the compressor to start against a high head pressure if the compressor has just finished a refrigerating cycle.

By locating the evaporator coil 106 adjacent the ceiling a number of advantages are obtained. First, the location of the evaporator coil within an air duct, particularly when supported on a shelf having a layer of insulation such as 21 enables the freezer to present a storage compart interior that is free of frost at all times. Secondly, during defrost operations the location of the evaporator coil 106 adjacent the ceiling allows the air within the box tostratify since the evaporator fan runs only during the refrigerating cycle. That is, there will be no problem from the continued circulation of air by convection since the air warmed will be that immediately surrounding the evaporator coil 106 and will therefore 'be completely removed from the evaporator coil 106,

will drain completely through the drain tube 50, and will therefore allow completely unobstructed air passage through the air duct when the refrigeration apparatus starts on a refrigerating cycle. The evaporator fan 24 may be advantageously connected to a switch activated by'the opening of the door so that the fan 24 is turned off when the door is opened, thus not distorting the impression that the heat sensitive element 54 receives of the air temperature within the box. The heat sensitive element 54' will still maintain maximum sensitivity. since it is located in the duct adjacent the top of the box where the air would tend to be warmer first. I

It is also to be noted that the evaporator fan 26, the block'of insulation 19 through which the fan motor shaft 25 is inserted and the fan blade 24 may be constructed to be removed as a unit in either direction for easier maintenance. That is, by opening the' front door 14 and removing the drawer 18 the entire fan, insulation" block, and motor combin'ationmay be removed from the front to be serviced. The built-in unit would not be moved from its installation flush against the wall. and apparatus on either side.

As may best be seenin FIG. HI the exhaust 'port 27 may be located so that a portion of its direct air stream will be directed upon a pluralityof ice cube trays 19 so that a quick freezing'of the tubes is possible.

.Referring to FIG. X there is illustrated a schematic diagram of a control circuit for the apparatus of this invention. The compressor motor 102, is connected in series with the thermostatic control 210 having single pole-single- throw switch terminals 211, and 212 between power leads 201 and 202. When the temperature inside the storage compartment of the freezer as determined by the heat sensitive element 54 rises above a predetermined temperature the terminals 211 and 212 are connected starting the compressor. When the temperature in the freezer falls to a second predetermined temperature, as

determined by the heat sensitive element 54, the circuit between terminals 211 and 212 is broken. Since controllers of this type are well known the thermostatic control is not shown in detail. V

Connected to the same terminal 211 as the compressor motor 102 is a defrost thermostatic controller 220. The controller 220 comprises a timer motor 221 directly connected to terminal 211 and single-pole-double-throw switch having terminals 222,223 and 224. The defrost controller 220 is of the type that initiates a defrost interval in response to time and terminates the defrost interval in response to temperature. That is, the timer motor 221 may be connected to run whenever the compressor runs. After a predetermined time the motor is operative to cause the terminals 222 and 223 to be connected. This energizes the solenoid valve 122 and since the compressor is running immediately starts defrosting. When the ice and frost is removedrfrom the evaporator coil 106 and the drip pan 22, the heat sensitive element 53 is operative to open the circuit between terminals 222 and 22 3 and close a circuit between terminals 222 and 224. 'The valve 122 is thus deenergized and closed. 7 Since the heat sensitive element 54 should be warm enough to keep the terminals 211 and 212 of the'control 210 connected the condenser fan 130 and the evaporator fan 26'are energized through terminals 222 and 224 of the controller 220; The evaporator fan 26 is not connected directly to the power lead 201 as is thecondenser fan 130 but instead is connected throughthe'single-poledouble-throw switch 230 to the lead 201. The switch 230 is operated by the door to the storage compartment.

When the door is closed terminals 232 and 234 are connected allowing the evaporator fan 26 to be energized. When the door is open terminals 232 and 233 are connected, deenergizing the evaporator fan 26 and energizing the interior light 29. It is to be noted that other circuit arrangements maybe'utilized to accomplish the 'results desired herein and the circuit shown in FIG. X

is illustrative of these.

In conclusion it is pointed out that while the illustrated example con'stitutes a practical embodiment of our invention, we do not limit ourselves to the exact details shown, since modification of the same may be varied without departing from the spirit of this invention.

Having described the invention, we claim: Y

1. Refrigeration apparatus comprising a. refrigeration cabinet having a storage compartment and an apparatus compartment; false wall means within said storage compartment forming an air duct; blower meansadapted to circulate air into said duct and discharge said air through an exhaust port'located in said false wall; said blower means comprising a fan means in said .exhaustport; said fan meansbeing driven by a shaft of a motor mounted in a recess on the exterior of said refrigerator cabinet thereby allowing said cabinet tomaintain a flush outer wall; air circulation means for cooling said apparatus in said apparatus compartment; means for diverting a portion of said cooling air from said apparatus compartment into said recess whereby said fanmotor is cooled.

2. Refrigeration apparatus comprising a refrigeration cabinet having a storage compartment and an apparatus compartment; blower means adapted to circulate air withinsaid storage compartments-aid blower means comprising f an means located within said storage compartment; said fan means being driven by a 'shaftextending through insulation surrounding said storage compartment; said shaft being driven by a motor which is mounted in a recess on the exterior of said refrigerator cabinet thereby allowing said cabinet to maintain a flush outer wall; apparatus compartment air circulating means located within said apparatus compartment; means for diverting a portion of said air being circulated in said apparatus compartment into said recess to cool said fan motor.

A 3. Refrigeration apparatus comprising a refrigeration cabinet having astorage compartment and an apparatus compartment; blower means adapted to circulate air within said storage compartment; said blower means comprising fan means located within said storage compartment; said fan means being driven by a shaft extending through insulation surrounding said storage compart merit; said shaft being driven by a motor which is mounted in a recess on the exterior of said refrigerator cabinet thereby allowing said cabinet to maintain a flush outer Wall; apparatus compartment air circulating means located Within said apparatus compartment; means for diverting a portion of said air being circulated in said apparatus compartment into said recess to, cool said fan motor; said blower means including said fan means, motor, and insulation surrounding said shaft being constructed as a unit to allow removal of the entire blower unit from either the interior or exterior of said' cabinet for maintenance.

4. Refrigeration apparatus comprising a refrigeration cabinet having a storage compartment; evaporator. coil means disposed across and adjacent to a ceiling of said compartment; -means supporting said evaporator coil; false wall means cooperating with said support means to form an air duct across said ceiling and one wall of said compartment; blower means adapted to circulate air into said duct adjacent a door wall of said compartment and discharge said air through an exhaust port in said false wall; and refrigeration system means adapted to supply refrigerant to said evaporator including a defrost coil and a compressor; said defrost coil being in intimate heat exchange relationship with said evaporator coil; said defrost cell having an inlet coupled through valve means to a high pressure side of said compressor; said means supporting said evaporator coil including a drip pan extending under the entire area of said evaporator; and defrost thermostat means for controlling said valve having a heat sensitive element disposed in heat exchange relationship with said drip pan.

5. Refrigeration apparatus comprising a refrigeration cabinet having a storage compartment; evaporator coil means disposed across and adjacent to a ceiling of said compartment; means supporting said evaporator coil; false Wall means cooperating with said support means to form an air duct across said ceiling and one wall of said compartment; blower means adapted to circulate air into said duct adjacent a door wall of said compartment and discharge said air through an exhaust port in said false wall; and refrigeration system means adapted to supply refrigerant to said evaporator including a defrost coil and a compressor; said defrost coil being in intimate heat exchange relationship with said evaporator coil; said defrost coil having an inlet coupled through valve means to a high pressure side of said compressor; said means supporting said evaporator coil including a drip pan in intimate heat exchange relationship therewith; and defrost thermostat means for controlling said valve having a heat sensitive element disposed in heat exchange relationship with said drip pan.

6. Refrigeration apparatus comprising a refrigeration cabinet having a storage compartment; evaporator coil means disposed across and adjacent to a ceiling of said compartment; means supporting said evaporator coil; false wall means cooperating with said support means to form an air duct across said ceiling and one wall of said compartment; blower means adapted to circulate air into said duct adiacent a door wall of said compartment and discharge said air through an exhaust port in said false wall; and refrigeration system means adapted to supply References Cited in the file of this patent UNITED STATES PATENTS 2,107,400 Stabbal Feb. 8, 1938 12,247,736 Tull July 1, 1941 2,247,950 Kucher July 1, 1941 2,285,946 Kalischer June 9, 1942 2,315,221 Philipp Mar. 30, 1943 2,451,903 Bavamann Oct. 19, 1948 2,532,816 Kurtz Dec. 5, 1950 2,711,456 Goodhouse June 21, 1955 2,741,098 Janos Apr. 10, 1956 2,876,630 Boling Mar. 10, 1959 2,882,696 Herrmann Apr. 21, 1959 2,895,307 Nonomaque July 21, 1959 2,907,184 Schumacher Oct. 6, 1959 2,909,907 Swanson Oct. 27, 1959

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