US2487068A - Refrigeration apparatus having an air pump circuit - Google Patents

Description

Nov. 8, 1949 N. MORRIS 2,437,063

REFRIGERATION APPARATUS HAVING AN AIR PUMP CIRCUIT Filed 4 m 26. 1944 a Sheets-Sheet 1 f W11)! I v 5 QbabV a/W 9160 0143: BY

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' ATTOLQ/VEY Nov. 8, 1949 N. MORRIS 2,487,063

REFRIGERATION APPARATUS HAVING AN AIR PUMP CIRCUIT Filed April 26. 1944 8 Sheets-Sheet 2 4 4 I; r. d 40 INVENTOR. 96a 66 a -v Q'I'Cwmba Nov. 8, 1949 N. MORRIS 2,437,058

REFRIGERATION APPARATUS HAVING AN AIR PUMP CIRCUIT Filed April 26, 1944 e Sheets-Sheet s IRE- E L97 v @3 7 i INVENTOR.

T Shir/60w 9760/2314 J BY Nov. 8, 1949 N. MORRIS REFRIGERATION APPARATUS HAVING AN AIR PUMP CIRCUIT Filed April 25, 1944 8 Sheets-Sheet 4 INVENTOR. S'Gal'aw Qfiaomio,

I REFRIGERATION APPARATUS HAVING AN.AIR PUMP CIRCUIT A Filed April 2.6. 1944 N. MORRIS Nov. 8; 1949.

8 Sheets Sheet 5 INVENTOR. 9Gala-v 9130/0116,

krro Awvs r N. MORRIS 2,487,068 REFRIGERATION APPARATUS HAVING AN AIR PUMP CIRCUIT Nov. 8, 1949 8 Sheets-Sheet 6 Filed April 26, 1944 INVENTOR. v a W 97190 01443 A TO/QA/f Y N. MORRIS REFRIGERATION APPARATUS HAVING AN AIR PUMP CIRCUIT -8 She ets-Sheet 7 a I L 4 4 4/ ,T M a/ a w WW 4 W m w 7 2 F w "IN V EN TOR.

cLM 312904:

Nov. 8 1949 N. MORRIS 2,487,068

REFRIGERATION APPARATUS HAVING AN AIR PUMP CIRCUIT Filed April 25, 1944 8 Sheets-Sheet 8 YET-E E INVENTOR. 90a [1641M 9727042214) Arron/v5 0 Patented Nov. 8, 1949 I UNITED STATES PATENT OFFICE REFRIGERATION APPARATUS HAVING AN Am rum cmcurr Nathan Morris, Silver Spring, Md., assignor; by mesne assignments, to American Instrument 00., Inc., a corporation of Maryland Application April 26, 1944,v Serial No. 532,807 5 Claims. (01. 82-6) 1 My invention relates broadly to refrigeration and more particularly to the system and apparatus for producing sub-zero temperatures.

One of the objects of my invention is to provide a method of controlling extremely low tem-- peratures in a refrigeration cabinet. with a high degree of precision.

Another object of my invention is to provide a construction of apparatus for producing and maintaining relatively low temperatures in a cabinet utilizing solidified gas as the refrigerant.

Still another object of my invention is to provide a refrigeration apparatus having a solidified gas refrigeration cabinet with a circulator therein for cyclicly pumping low temperature gas through a work chamber.

A further object of my invention is to provide a construction of circulator and volume control unit which may be readily installed in a solidifled gas refrigeration cabinet on a quantity production basis.

Still another object of my invention is to provide a construction of seal between externally arranged driving motors and fans internally arranged within a refrigeration cabinet for minimizing refrigeration loss transfer between the exterior and interior of the cabinet.

A further object of my invention is to provide a construction of observation window for subzero refrigeration cabinets including means for minimizing refrigeration loss.

A still further object of my-invention is to provide a construction of work chamber for subzero cabinets including means for permitting an operative to extend his arms through especially prepared sleeve-like apparatus in the wall of the cabinet for manually working within the cabinet while minimizing refrigeration loss.

A further object of my invention is to provide a system of dual fan operation for low temperature refrigeration cabinets with means for cooperatively controlling the operation of the fans whereby one of the fans may be constantly driven for maintaining circulation of the refrigerating gas within the cabinet while the other of the fans is intermittently driven according' to the temperature requirements for the particular work being performed within the cabinet.

Other and further objects of my invention reside in the method of operation and details of construction of the refrigeration apparatus set forth in the specification hereafter following by reference to the accompanying drawings in which: Figure l is a plan view of one construction of refrigeration apparatus embodying my 2 invention; Fig. 2 is a vertical sectional view taken on line 2-2 of Fig. 1; Fig. 2a is a detailed view showing one arrangement of sealing the entrance way for the shaft which connects one of the external driving motors to one of the gas circulating fans in the cabinet structure; Fig. 3 is a horizontal sectional view through the cabinet structure taken substantially on line 3-3 of Fig; 2; Fig. 4 is a transverse vertical sectional view taken through the cabinet structure substantially on line 4-4 of Fig. 3; Fig. 5 is a vertical sectional view through the cabinet structure taken substantially on line 5-5 of Fig. 6; Fig. 6 is a plan view similar to the plan view of Fig. 1, but illustrating one section of the hinged top of the cabinet opened to show the interior of the Dry Ice compartment; Fig. '7 is a detailed sectional view of the blower and associated duct and volume controlling valve employed in association with the Dry Ice compartment; Fig. 8 is a horizontal sectional view through the blower taken substantially on line 88 of Fig. 7; Fig. 9 is a vertical sectional view through the blower and associated duct and valve system taken substantially on line 9-9' of Fig. 7; Fig. 9a is a perspective view broken away and illustrated in section of the rotor used in the blower system of my invention; Fig. 10 is a vertical sectional view through the blower and associated duct system taken substantially on line Ill-10 of Fig. '7; Fig. l1 is a detailed perspective view of one portion of the blower housing; Fig. 12 is a perspective view of the supporting plate used in association with the blower housing; Fig. 13 is a horizontal sectional view showing the valve structure used in association with the duct system of the blower; Fig. 14 is a transverse sectional 'view through the valve structure on line l4-|4 of Fig. 13; Fig. 15 is a top plan view of the duct system and associated gas deflector plate with parts broken away and illustrated in section to show the blower within the blower housing associated with the duct; Fig. 16 is a perspective view of the blower unit duct and associated control valve; Fig. 17 is a front elevational view-of the control valve for controlling the gases that are pumped from the Dry Ice compartment into the work compartment; Fig. 18 is a detailed sectional view through the observing window in the cabinet with the groups of plate units making up the observation window for the refrigeration cabinet; Fig. 20 is a wiring diagram illustrating the electrical circuit arrangement for the control units employed in the refrigeration system of my invention; Fig. 21 is a vertical sectional view through a modified form of cabinet structure embodying my invention, the view being taken centrally through the Dry Ice compartment and through the work compartment; Fig. 22 is a view similar to the view illustrated in Fig. 21 where the section is taken in a position to illustrate the duct leading from the blower in the Dry Ice compartment to the work compartment; Fig. 23 is a detail view taken through one of the hand holes provided in the side wall of the cabinet structure; Fig. 24 is an elevational view showing one of the plugs in position for closing'the hand hold, parts being broken-away and shown in section to more clearly illustrate liner for the hand hole; Fig. 25 is an elevational view of one of the protective sleeves used in association with one of the hand holes in the side wall of the cabinet, the view being broken away and shown in section; and Fig. 26 is an end view of the protective sleeve illustrated in Fig. 25.

Referring to the drawings in more detail reference character i designates the refrigeration cabinet embodying my invention and in which laminated insulation material having high heat insulation properties constitutes the wall structure of approximately six inches in thickness. The insulation material is covered externally by suitable heat insulation surfacin material such as laminated board represented at 2. The interior of the cabinet is provided with a metallic lining represented at 3which has all joints well filled and caulked to eliminate insofar as is practicable the loss of refrigeration by heat transfer through the walls of the cabinet. A cover formed in sections represented at 4 and 5 hinged together as represented at 6 extends over the cabinet structure and is secured in tight sealed relation thereto by hasps l which when forced into securing position insure a gas-tight joint between the metallic peripheral extension 8 of the lining 3 and the metallic facing 9 and ll! of the cover sections 4 and 5. The cover sections 4 and 5 are constructed in a manner similar to the construction of the main cabinet in that the internal laminated heat insulation is faced on its lower surface by metallic material 9 and I and covered on the peripheral edges and upper surface by laminated wood or other insulation material indicated at H.

The interior of the cabinet is divided into a work chamber represented at l4 and a Dry Ice compartment represented at lby means of a partition I6 of insulation material. The partition l6 extends transversely of the interior of the cabinet termination above the bottom of the cabinet at ll. The partition is formed from laminated insulation material enclosed by metallic sheet-like material represented at l8, one surface of which forms the transverse wall of the work compartment 14 and the opposite surface of which I9 constitutes one wall of the Dry Ice compartment. The Dry Ice compartment which terminates at the level I! is arranged to receive a basket or box-like carrier represented at that is provided with-an openwork meshlike side 2| atone end thereof for the free circulation of gases under control of the blower represented generally at 22.

The blower and the accessories associated therewith are shown more clearly in Figs. 7-16. The blower includes mounting means in the form of a circular plate 23 illustrated in Fig. 12 which 4 is secured by screws 24 through the interior side wall of the cabinet with the central aperture 25 thereof arranged concentrically with and fitting over the protruding end of tubular member 28 that extends through the side wall of the cabinet and serves as a guide through which the drive shaft 21 extends. Drive shaft 21 is connected to motor 28 supported externally of the cabinet on suitable mounting bracket 29. A sealing gland is provided between motor 28 and the external side wall of the cabinet as represented at 30 for preventing loss of refrigeration. The sealing gland comprises a substantially resilient gasket which is compressed between the end of the motor frame 28 and the side wall of the cabinet 7 for substantially preventing heat exchange through the tubular member 26.

The supporting plate 23 is provided with a plurality of radially extending tongues or oilset lugs indicated at 3| spaced from the side wall of the cabinet sufficiently to permit one portion of the housing for the fan represented at 32 to have the aperture 33 therein with radially disposed notches 34 which extend therefrom to be aligned with and slipped over lugs 3!. When the housing 32 is assembled in position it is slightlyv sition by screws 24.

The rotor shown more particularly in Figs. 8, 9 and 9a at 35 may now be readily mounted on shaft 2'7 by engagement of set screw 36 in hub member 3? thereof with the shaft 21. The rotor 35 is pressed from sheet metal and provides a multiplicity of radially extending fan blades 38 which are effective to develop a very substantial gas flow through the fan housing. With the fan 35 mounted in position, the coacting side portion of the fan housing shown at 39 is mounted in position in the fan housing 32 with the aperture 40 therein registering with the end of the rotor 35 constituting the fan. The intake for gases is established through the center aperture 40 of the housing which is in close proximity with the open mesh side wall 2| of the Dry Ice container 20. The delivery end of the fan 35 is connected to the duct system 4| which, when the fan housing is properly mounted in position, extends vertically in the Dry Ice compartment and forms a slip connection coupling means with the depending end 42 of the elbow 43 of horizontally extending duct 44. The horizontally extending duct 44 contains deflector or streamlining guide plate 45 therein for reducing friction to gas flow through the duct system. The end of the horizontally extending duct 44 projects through a recess 44aformed in the partition I6 and projects into the upper portion of the work compartment l4. The end of the duct 44 is provided with a transversely extending frame member 41 which fits thereon and serves as a guide for an adjustable plate member 48 which may be adjusted between sets of coacting guide grooves indicated at 43 and 50. The adjustable plate 48 has a projecting finger grip portion 5| enabling the plate to be manually grasped and moved to selected positions to fully In order to confine the forced gas fiow into the work compartment from the refrigeration compartment to the duct system I provide a deflector plate 63 which extends from the top of the guide plate frame 41 to a position establishing sealed relation with the entire surface of the cover section 4. As represented in'Flg. 4 the deflector plate 53 extends only partially across the cabinet forcing the gases to pass through the confined space indicated at 46 so that the return gases are free to pass through the elongated slot or recess indicated at 46 in their convection path from the work compartment into the refrigeration compartment.

In addition to the blower 22 which I have described I also provide an arrangement of fan 55 which is mounted below the refrigeration compartment centrally of the interior of the cabinet on shaft 56 which extends through the tubular member 51 in the side wall of the cabinet to the motor 58 supported on bracket 59 on the exterior of the cabinet. A compressible gasket 68 is compressed between the end of tubular sleeve 51 and motor housing 58 for providing a gas-tight seal and preventing heat exchange between the exterior atmosphere and the interior of the cabinet. An annular ring member 6| is secured against the gasket 60 forcing the gasket 60 into tight sealing relation with the end of the motor'housing. An annular rim member 62 fits over the ring and gasket 60 as shown. The fan 55 is located beneath the refrigeration compartment and in line with the heaters 63 that are supported on frame 64 that extends transversely of the cabinet immediately adjacent the partition I6. The heaters 63 are constituted by wire coils which may be arranged in sections and electrically connected in series or multiple arrangement for securing different temperature conditions. 7

In Fig. 20 I have shown the switch system 85 which is mounted in a control box externally of the cabinet for determining the parallel or series arrangement of the wire coils 63a and 63b which comprise the heaters 63. The connection of the heaters into the power supply circuit 66 is controlled by mercury switch 61 actuated by armature 68 controlled by solenoid winding 69 which is energized or deenergized in accordance with the position of the thermostat 18 the control element of which extends into the cabinet as represented in Figs. 2, 3, 4, 21 and 22. The thermostat is connected to the direct current control circuit which includes the rectifier bridge shown at H connected to secondary winding 12 of transformer 13 whose primary winding 14 connects to the power supply circuit 66. A main switch is provided for cutting off the entire cabinet electrical service f1 om the power supply line 66 which is usually 110 volts alternating current. The transformer l3 appropriately steps down the power supply to the thermostatic control circuit for operation of solenoid winding 69. Fan motor 58 normally operates continuously although the condition of heat within the work chamber may vary. Such condition is controlled by the cutting on or off of the wire coils 63a and 63b of the heater 63 as the thermostat 10 may determine. Selector switch 65 is manually controlled from the apparatus control panel exterior of the cabinet structure for connecting thewire coils 63a and 63b in parallel in order to obtain maximum temperature conditions or connecting the wire coils 68a andv 63b in series in order to obtain lower temperature conditions or to select merely a single wire coil and eliminate the other wire coil from the circuit in order to obtain medium temperature conditions.

In addition to the mercury switch 6! controlled by member 68 which is operated by solenoid winding 69, I also provide a coacting mercury switch 11 having its contacts connected to selector switch 18 to the power supply line 66 and to the blower motor 28. Selector switch 18 is manually controlled from the apparatus control panel externally of the cabinet structure and when moved to contact 19 places the blower motor under control of mercury switch TI, but when moved to contact 88 eliminates the control of blower motor 28 from contacts 11 and allows the blower motor 28 to run continuously except as may be determined by the externally manually controlled switch 8| mounted on the apparatus panel. An alternative of this arrangement includes a provision of resistors allowing blower motor 28 to be continuously controlled by mercury switch 11 at different speeds. The manually operated switch 8| when closed places blower motor 28 under control of the set of contacts in mercury switch 11 assuming manually controlled switch 18 to be moved to contact 19. So long as blower motor 28 is operating pilot lamp 82 is lighted through suitable power reducing resistor 83, the pilot lamp 82 and resistor 83 combination being effectively inparallel with blower motor 28 and the power supply line 66. Without pilot lamp 82 operating on the apparatus control panel externally of the cabinet, the operating condition of blower motor 28 cannot readily be determined inasmuch as observation into the cabinet from the exterior thereof is restricted to a relatively small observing windowand the sound of the running blower within the cabinet is substantially mufiled by the cabinet structure. A suitable convenience outlet represented at 84 is connected in a shunt with the power supply line 66 and mounted on the apparatus control panel externally of the cabinet structure.

I have heretofore alluded to the observing window of the cabinet structure and invite attention to Figs. 18 and 19 for a more detailed understanding of the special construction that I have developed for preventing heat exchange between the interior and exterior of the cabinet. The window is made up of groups of vacuum sealed glass panels represented at 85 and 86. The group 85 consists of a pair of plates spaced at their peripheries by spacer member 81 with the air evacuated from the space therebetween. The group of plates 86 consists of two sets of plates spaced at their peripheries as indicated at 88 and 89 with the air evacuated from the space therebetween. These two sets of plates are spaced by the intermediate frame represented at 88 consisting of fiat strips mutually interfitting with each other by coacting slots formed in the strips and apertured in the sides thereof as represented at 9| to'allow fiow of air from the space between the groups of plates represented at 92 and the space behind the plates represented at 93 within which bags of silica-jell 94 are arranged. The silica-jell in the bags at 94 possesses a high degree of affinity for absorbing moisture which may develop between the groups of plates in consequence of their subjection to violent temperature changes. The sets of plates and the spacing strips 90 therebetween are set into the recess 7 99 in the aperture 96 which extends through the wall of the cabinet and are secured in position by means of suitable molding 91 extending around the outside marginal edge of the aperture 95 external to the cabinet. Thus the observing window permits full vision of the interior of the working chamber it while preventing heat exchange between the interior and exterior of the cabinet.

As illustrated in Figs. 21 and 22 I may arrange the observingwindow in one of the side walls of the, cabinet structure in the position represented at." to permit observation of operations which may be carried out in the working chamber 84 where the arms of the operative may be passed through arm holes provided adjacent the observation window in the wall of the cabinet as represented at 99. The arm holes 99 are normally closed by plugs of insulation material represented at I09.

I have shown the plugs more clearly in Figs. 23 and 24. It will be observed that the side walls of the cabinet I is formed from insulation material having an inner metallic lining 3 andan exterior laminated facing 2 lined by a tubular sleeve member ifil. The tubular sleeve member iill is formed from insulation material and has opposite ends of reduced section one of which shown, at it: fits through an aperture we formed in metallic lining 3 and the other of which shown at its projects beyond the external laminated facing 2 of the cabinet and is secured with respect thereto by a ring member Hi5. The joints are all caulked for preventing heat exchange. The tubular member is internally grooved as repre sented at 596 and serves as a securing means for the canvas sleeve it? which Ihave shown more particularly in Figs 25 and 26. The canvas sleeve it? is tapered in structure and serves as an arm covering through which the operative may project the arm with the canvas sleeve I01 snugly fitting about the arm as an extended cover therefor. The groove 106 is formed adjacent the working chamber end of the tubular member it! and serves as a securing means for the end of sleeve i9? therein by reason of the arrangement of the resilient expandible ring I08 which clamps the sleeve adjacent the inner face of the tubular member. The opposite end of the sleeve it! terminates in an elastic wrist band H09 through which a gloved hand of the operative may be thrust for maintaining the passage through the tubular member substantially closed while the arm of the operative is extended through the tubular member. With the plug I removed the operative inserts the gloved hand through the elastic wrist band I09 and then projects the arm wholly into the work chamber i4.

Inasmuch as both arms of the operative may thus be extended into the working chamber it and operations in the working chamber l4 observed through window 98, it is possible to perform various adjustments and operations within the working chamber at sub-zero temperatures without allowing excessive entry of heat from the exterior of the cabinet into the working compartment l4 and without allowing appreciable leakage of refrigerant.

The plug I00 consists of multiple layers of insulation material represented at I000. confined in stacked relation by suitable bolt members lllflb which may also serve as securing means for handle member H0 enabling the orifice to be immediately plugged after an operation thereby preventing excessive drop in temperature within the working compartment i l.

8 The cabinet is installed in a location away from heated radiators or direct sunlight. It is mounted on a reasonably level floor or platform and the power circuit 96 connected to a suitable power source such as 110 volt 60 cycle alternating current. I find it desirable to ground the cabinet, power service conduit system and interior of the cabinet wall as represented schematically at land 2 in Fig. 20.

Dry Ice represented generally in commercial block form at i5 is deposited in basket 20. the work set up in the working compartment l4 and the cabinet closed. The Dry Ice is pumped over as a gas into the working compartment by blower 35 under control of the thermostat l9 and heater system 63. Assuming that a temperature 0! minus 50 degrees F. is desired, ther-' mostat I0 is set for this temperature and locked. Calibration can be made by observing a thermometer inside the working chamber and checking the thermometer reading the instant that the pilot lamp 82 is illuminated on the control panel exterior to the cabinet which shows the instant that the blower motor 28 is energized for the minus. 50 degrees F. setting of thermostat 10.

Operation of cabinet at 40 deg. to 100 den. F.

In order to operate the cabinet over ranges, for example, of --40 to -100 F. the Dry Ice compartment 20 is filled to the top with Dry Ice crushed to approximately egg-size. It is advisable not to use powdered or too finely pulverized ice as it increases the surface area-,- and, in turn,

of degrees F., it may be necessary to recharge the Dry Ice compartment with more Dry Ice which, in turn, increases the surface area and rapidly brings the box down to degrees F.

For any temperature control in the range of -40 degrees F. to -100 degrees F., the slide damper 48 shouldbe adjusted to half-open position. Simply set the regulator it for the desired temperature in this range with the heat switch 65 in the oil position, and it will give satisfactory regulation.

For temperatures from 0 degrees to -40 degrees F., the slide damper 48 should be in the open position.

When working at or near 0 degrees F. or above, it is advisable to put the Dry Ice in in as large lumps as possible (normally 1 or 2 pieces which will fill compartment). This provides better control at these temperatures. It may also be necessary at any temperature from 20 degrees on up to room temperature to turn the heater switch 65 to low position to compensate for leakage through the interior insulation.

Operation from room temperature to 220 degrees F.

The same procedure is followed for setting the thermoregulator 10 for these higher temperatures. Any Dry Ice that may be present in the box should be removed, and the heater switch 65 turned to high until desired temperature is reached. It will require from 3 to 4 hours for the box to rise from room to 220 degrees F. with the switch on high. Switch positions are as follows:

From room to 120 degrees F.: "low From 120 degrees F. to 160 degrees E: "medium From 160 degrees F. to 220 degrees F.: "high" In opening the lid of the box at the high temperatures, it is advisable that no fan or draft of cool air be made to strike the observation glass at the underside of the lid as sudden change of temperature might crack the glass.

Safety thermostat In order to avoid dangerous conditions which might result from failure of the thermostat HI to function, I provide a safety thermostat H6 in the heater circuit which will open at approximately 230 degrees F. rreventing the box from rising any higher than this, thereby causing damage. This safety thermostat may be conveniently located on the lower left-hand of the heater frame 64.

Normal Dry Ice consumption at 100 degrees F. after the initial pull-down is approximately 2 lbs. per hour. Dry Ice consumption at -40 degrees F. is approximately 1.5 lbs. per hour. Dry Ice consumption at degrees F., with heat switch on low heat (input 125 watts) is approximately 2 lbs. per hour. Dry Ice consumption at 0 degrees F., with no heat on and Dry Ice in one large piece, is approximately 1.25 lbs. per hour.

The equipment of my invention is highly practical inasmuch as Dry Ice is now commercially obtainable through wide distribution channels and provides a convenient means for securing refrigeration at the temperatures obtained in the system of my invention.

The only maintenance required with the equipment is the occasional oiling of the fan motor 58 and blower motor 28. Replacement of the pilot light 82 is readily made. It may be necessary to renew the heater coils 63a and 63b from time to time.

The apparatus of my invention has wide application in industry such as the shrinking of rivets for mass production rivetin operations, the chilling of aluminum rivets to retard hardening and maintain them soft enough for driving; the storing of metal parts at low temperatures for conditioning the parts prior to use as in chilling the parts for expansion fitting; the treating of tool and other steels by chilling to produce desired characteristics otherwise difficult to obtain by ordinary methods of treatment; the accelerated ageing of metals; the storing of serums, blood, chemicals, etc.; the testing of aircraft equipment and materials of every description for determining their durability, performance, etc.

at low temperatures and as a food-freezing pilot plant. The portability of the equipment is one of its outstanding features in addition to its low cost and simplification of design for quantity production. v

In the operation of the refrigeration apparatus of my invention the gas from the solidified gas compartment is accumulated in a confined area or column in the duct system -44 which serves as a trap from which the gas does not run out until the blower fan is initiated in motion.

The confined column of .gas is then lifted by the fan 35 and pumped through the work compartment for maintaining the sub-zero temperature therein. This process of lifting and pumping the column of gas continues until the predeteriii) 10 mined thermostat controlled temperature in the work compartment is reached.

Wherever in the specification and/or claims I may use the expression dry ice I desire that this be understood to mean any solidified gas. My invention is not restricted to the use of CO2 as any solidified gas may be employed for securing the sub-zero temperatures obtainable in the apparatus of my invention.

Although I have described my invention in certain of its preferred embodiments, I realize that changes and modifications may be made and I intend no limitations upon my invention other than may be imposed by the scope of the appended claims.

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

1. Refrigeration apparatus comprising a cabinet structure including .a solidified gas refrigeration compartment and a work compartment, a blower disposed adjacent the base of said solidifled gas refrigeration compartment for pumping gas therefrom into said work compartment, a duct connected with said blower and extending vertically within said refrigeration compartment and horizontally into said work compartment for delivering refrigerated gas thereto a circulator disposed in said work compartment, and means for intermittently operating said blower and continuously operating said circulator.

2. Refrigeration apparatus comprising a cabinet, a transversely extending partition dividing said cabinet into a work compartment and a solidified gas refrigeration compartment, said partition being recessed adjacent the top and bottom thereof, a removable top extending across said cabinet in a position in which a predetermined gap is maintained between the top recess in said partition and the under-surface of the top that extends across the cabinet, a blower disposed adjacent the base of the solidified gas refrigeration compartment, a duct connected with said blower and extending through said partition and into said work compartment, a deflector plate intermediate the top recess in said partition and the under-surface of the top of said cabinet structure adjacent the passage of the duct through the partition and operating to restrict the return passage for circulating gas from said work compartment to the solidified gas re 'rigeration compartment to a path immediately adjacent said solidifled gas compartment between the top recess in said partition and the under-surface of said cabinet. v

3. In a temperature controlled cabinet, a heat insulated wall structure forming a refrigeration cabinet, a substantially circular plate member secured to the interior surface of said wall structure and apertured for the passage of a drive shaft therethrough, a driving motor mounted exteriorly of said wall structure and connected with said drive shaft for rotatably driving the drive shaft, an annular skirt formed on said plate member lugs extending radially from the annular skirt of said plate member in positions spaced from the interior wall of said cabinet, 2. fan housing having an opening in one side thereof recessed to coact with the lugs carried by said plate member and insertable over said plate member with said lugs passing through the recesses therein, said housing being angularly movable to a position in which the housing is secured in operative position by the coaction of said lugs with the inner periphery of the opening in the housing, a duct connected with said wall, lugs projecting radially from said plate in position spaced from the interior surface of v the wall of the cabinet, said plate being apertured for the passage of a motor drive shaft.

a motor mounted exteriorly of said cabinet and having its drive shaft extending through said heat insulated 'wall and through said plate member, sealing means between said. motor and the entrance of said shaft through said wall structure, a fan housing angularly movable from an assembly position to an operating position within said cabinet, said fan housing having an opening recessed at the periphery thereof for the passage of said plate and the lugs thereon, the said housing being engageable at the periphery 'of said opening by the lugs on said plate when the housing is shifted to operating position within said cabinet structure, a duct connected with said housing and extending into said refrigera tion cabinet and a fan carried by said shaft within said housing.

5. Refrigeration apparatus comprising a cabinet, a transversely extending partition dividing said cabinet into a work compartment and a solidified gas refrigeration compartment, said partition being recessed adjacent the top and bottom thereof, a removable top extending across said cabinet in a position in which a predetermined gap is maintained between the top recess in said partition and the under-surface of the top that extends across the cabinet, a blower disposed adjacent the base of the solidified gas refrigeration compartment, a duct connected with said blower and extending through said partition and into said work compartment, a

12 deflector plate intermediate the top recess in said partition and the under-surface of the top of said cabinet structure adjacent the e of the duct through the partition and operating to restrict the return passage for circulating gas from said work compartment to the solidified gas refrigeration compartment to a path immediately adjacent said solidified gas compartment between the top recess in said partition and the under-surface of said cabinet, the top recess in said partition above said solidified gas refrigeration cabinet being open for the return passage of gas from the work compartment to said solidified gas refrigeration compartment, and means in said duct r substantially coplanar with said partition for variably controlling the volumetridtransfer of gas from said solidified gas refrigeration compartment to said work compartment.

NATHAN MORRIS.

REFERENCES c rrEn The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 123,077 Bate Jan. 30, 1872 1,124,778 Meuler Jan. 12, 1915 1,145,054 Boekel et al. July 6, 1915 1,269,612 Knoerr June 18, 1918 1,848,440 Spitzenberger et al. Mar. 8, 1932 1,934,864 Lambert et al Nov. 14, 1933 2,019,907 Jensen Nov. 5, 1935 2,046,967 Post July 7, 1936 2,243,999 Chapple June 3, 1941 2,266,346 Vincent Dec. 16, 1941 2,359,796 Russell Oct. 10, 1944 2,377,590 Talalay June 5, 1945 FOREIGN PATENTS Number Country Date 359,984 Italy June 9, 1938

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