US2496241A

US2496241A - Refrigerating method and apparatus utilizing dry ice

Info

Publication number: US2496241A
Application number: US642312A
Authority: US
Inventors: George B Wagner
Original assignee: BEEKMAN IND Inc
Current assignee: BEEKMAN IND Inc; BEEKMAN INDUSTRIES Inc
Priority date: 1946-01-19
Filing date: 1946-01-19
Publication date: 1950-01-31
Anticipated expiration: 1967-01-31

Description

Ian. M, 1950 A 2,496,241

G. B. W GNER V REFRIGERATING METHOD AND APPARATUS UTILIZING DRY ICE Filed Jan; 19, 1946 til 4:. at i application January I9, 19%, derial No. dd2,3l2

(Cl. 62-illi.5)

3 Illa.

This invention relates to novel refrigerating method and apparatus or the nature disclosed in my eopending application Ser. No. 66 L700, filed July into, new Patent l lo. ihtdilhlll, granted November to, race. In that application I have disclosed a storage chamber refrigerated hy evaporation gas from Dry Ice conducted from a Dry Ice box through arefrigerant pipe in the chamher. The temperature oi the chamber is controlled by venting the pipe at predetermined pressure. Normal evaporation of the Dry Ice is ordinarily sumcient to maintain desired temperatures within the chamber but emergencies may arise that will require an extra surge of evaporation to maintain a desired predetermined temperature. The primary object of my invention herein resides in the production of novel method and apparatus for automatically providing and main... taining such additional evaporation and refrigeration whenever occasion demands.

The invention contemplates the employment of means in the nature of a compressor associated with the refrigerant pipe for creating a suction and increasing the evaporation of the Dry Ice when the temperature in the chamber reaches a predetermined maximum, a thermostat in the being associated with the compressor for automatically effecting the suction when required. The production or a novel method and apparatus of this nature comprises a further object of the invention.

The compressor can be driven by any suitable motor under control of the thermostat and I have herein, by way of example, illustrated and described the employment of an electric motor and a gas pressure motor for this purpose. In the latter case, a second Dry Ice box is employed to provide evaporation gas for operating the motor and the thermostat is associated with and adapted automatically, when the temperature in the chamber reaches a predetermined maximum, to open a, valve and permit the flow of gas from the box to the motor, whereby causing the motor to operate the compressor and create the aforesaid suction.

These and other features of the invention will be best understood and appreciated from the following description of preferred embodiments thereof selected for purposes of illustration and shown in the accompanying drawing in which Fig. 1 is a fragmentary sectional view through an apparatus embodying my invention and employing an electric motor,

Fig. 2 is a like apparatus employing a gas pressure motor.

lid

d Referring first to Fig. l of the drawing, it indicates a double walled container insulated loctween the walls and it indicates a cover ior'the container. The interior chamber it of the contamer provides storage space for perishable products.

Centrally disposed within and spaced from the walls of the cover is a sheet aluminum Dry Ice box it. The box is supported directly on the bottom walllt of the cover by means or an aluminum collar it in metal to metal contact with the box and the bottom wall of the cover. The box is open at one end and can be anchored at its corners to the cover walls in the manner disclosed in my said copending application. The open end of the box is adapted to be closed by a removable closure including insulation it permitting the refilling of the box with Dry Ice it. A refrigerating pipe it extending from the box it outwardly i through the wall it is formed into a coil within the storage chamber it and vents outwardly through the cover at it. an adjustable pressure relief valve it is provided in the pipe lit and is adapted to permit the escape of gas from the pipe at predetermined pressure. A temperature of 110 F. is normally maintained in the box it and the temperature to be maintained inv the storage chamber depends on the product contained.

The box it is heavily insulated except for the metal to metal contact through the supporting collar it and the evaporation of the ice will be in proportion to the heat acqulredfrom the chambet it plus heat passing through the insulation. Ihave discovered that an insulated storage chamber can be refrigerated and a predetermined temperature maintained by evaporating Dry Ice within a closed chamber and conducting the evaporation gas therefrom through a pipe in the storage chamber at a predetermined pressure controlled at the vent end of the pipe, and I have employed this principle in the apparatus disclosed herein and in my said copending appllcation. The relief valve 28 is set to permit the escape of gas at a pressure which has been predetermined to produce and maintain the required low temperature in the storage chamber. It will be apparent that evaporation will be greater when relatively small pressure is required for escape of the gas and that the evaporating action will operate to lower the temperature in proportion to the evaporation. I have employed this apparatus in the storage of perishable products and have maintained a predetermined temperature of 45 F. uniformly within less than 2 over a. period of 104 hours. The device is particularly adapted to the preserving of whole blood, blood plasma and like perishable products and to the shipping of such products in containers embodying the invention.

The invention is applicable to wide and varied use in the storing and the combined storing and transporting of perishable products. Furthermore while it is particularly adapted to use-in portable containers it is equally adaptable to fixed storage refrigeration, large refrigeration truck units, etc. Such units are employed to transport fruit and other perishable products relatively long distances and through climates of varying temperatures, and when large shipments are being transported it may occasionally be necessary to provide additional refrigeration to maintain the chamber and products below a predetermined maximum temperature. My invention herein disclosed is particularly adapted to provide this additional refrigeration Mounted on the cover I2 is a compressor 30 as-' sociated with an electric motor 32. The pipe 2' is connected to the intake port of the compressor which has an exit port at 34. The motor is under the control of a thermostat 36 mounted on the cover wall It within the chamber l4 and con-. nected to the motor by wiring 38. The thermostat is set to cause the motor to operate at a predetermined maximum temperature which is to be maintained within the chamber ll.

Normally, the evaporation of the Dry Ice under control of the valve 28 is suilicient to maintain the required low temperature within the chamber but such factors as excessive extraction of heat from the stored products or passage of the load through an unduly warm atmosphere may temporarily cause the temperature in the storage chamber to rise to the predetermined maximum. In such case the thermostat automaticall operates to switch on the motor and drive the compressor which in turn reduces the gas pressure in the pipe 24 and increases the evaporation of the Dry Ice 22. Such increased surge of evaporation lowers the temperature in the storage chamber to a point below the predetermined maximum and serves in conjunction with the pressure control at 28 continuously to maintain the required range of temperature in the storage chamber even in extreme emergencies. It will be apparent that such maintenance is extremely important since the increased temperature of the chamber might otherwise deleteriously affect and cause loss of the perishable products.

In Fig. 2 of the drawing I have illustrated a similar refrigerating apparatus employing a gas pressure motor to drive the compressor. The parts of this apparatus which correspond to those illustrated in Fig. 1 are indicated by like reference characters primed and include a container it provided with a cover I! and having a storage chamber M. The cover has a bottom wall l6 and a Dry Ice box I! is supported on this wall by means oi. an aluminum collar it. A pipe 24' from the box I provides a refrigerating coil in the storage chamber, extends outwardly of the cover at 26 and is ventedby a relief valve 28'.

Mounted on the cover I! is a compressor II and a gas pressure motor 42 having pistons connected by a piston rod M as specifically described in my said copending application. The pipe 2G is connected to the intake port of the compressor which has an exit port at It. The motor 42 is operated by evaporation gas from Dry Ice 48 withm a second box so, this box being mounted am 4 iacent to but insulated from the box ii. A pipe 52 extends from the box ill to the intake port of the motor which has an exit port II. A valve It in the pipe 52 is under the control of a thermostat It secured to the bottom cover wall It. The thermostat is connected by wiring II to a solenoid associated with the valve 58 and adapted automatically to open the valve when the temperature in chamber I4 reaches said predetermined maximum.

As in the apparatus of Ffig. l, evaporation of Dry Ice 22' under control of the valve 28' is normally sufllcient to maintain the required low temperature within the storage chamber. However, if and when'the temperature within the chamber rises to said predetermined maximum, the thermostat automatically operates to open the valve 58 and permit gas under pressure to flow from the box 50 to and drive the motor 42. The motor in turn drives the compressor, reduces the gas pressure inthe pipe 24' and increases the evaporation of the Dry Ice 22', whereby lowering the tempera,- ture in the storage chamber in the manner heretoiore described in. connection with Fig. 1.

Having now disclosed my invention what I claim as new' and desire to secure by Letters Patent is:

l. A method oi maintaining an insulated storage zone at predetermined temperature, which consists in evaporating Dry Ice within a closed zone, conducting the evaporation gas therefrom along a closed path disposed in heat exchanging relation to the storage zone, controlling the temperature of the storage zone by venting the closed path at predetermined pressure, evaporating Dry Ice within a second closed zone, and utilizing the evaporation gas from the second closed zone to drive a compressor and create a suction from the first closed zone through said path when the temperature in the storage zone reaches a predetermined maximum.

2. A refrigerating apparatus comprising a container having a storage chamber within insulated walls, a closed Dry Ice containing box associated with the chamber, a refrigerant pipe from the box having an intermediate portion disposed within the chamber and an outer portion disposed outside of the chamber, a valve for controlling the vent of gas from the pipe exteriorly of the chamber, a compressor associated with the outer portion of the pipe outwardly of the valve for creating a suction from the box through the pipe, means including a thermostat in the chamber for automatically controlling the operation of the compressor, a second closed Dry Ice containing box, and means including a motor under control of the thermostat and arranged to utilize the evaporation gas from the second box to drive the compressor and create a suction from the first named box through the pipe when the temperature in the chamber reaches a predetermined maximum.

3. Arefrigerating apparatus comprising a container having a storage chamber within insulated walls, a closed Dry Ice containing box associated with the chamber, a refrigerant pipe from the box having an intermediate portion disposed within the chamber and an outer portion disposed outside of the chamber, a valve for controlling the vent of gas from the pipe exteriorly of the chamber, a compressor associated with the outer portion of the pipe outwardly of the valve for creating a suction from the box through the pipe, means including a thermostat in the chamber for automatically controlling the operation of the compressor, a motor associated with the com- Dressor, a second closed Dry Ice containing box,

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

6 UNITED STATES PATENTS Number Name Dcte Comer Dec. 19, 1933 Sherrick Mar. 20, 1934 Lewis Feb. 23, 193'? Scott Nov. 1.8, 1941 McMechan July 31, 1945 Isenberg et a1 Aug. 28, 1945 Newton Mar. 9, 1948