GB1595916A

GB1595916A - Portable cooling apparatus

Info

Publication number: GB1595916A
Application number: GB40223/77A
Authority: GB
Original assignee: Chattanooga Corp
Current assignee: Chattanooga Group Inc
Priority date: 1976-09-30
Filing date: 1977-09-27
Publication date: 1981-08-19
Also published as: CA1064717A; FR2366008A1; SE7710998L; DE2743919A1; JPS5348390A; DE7730219U1; NO143832C; NO143832B; NO773341L; DK431377A

Description

(54) IMPROVED PORTABLE COOLING APPARATUS (71) We, CHATTANOOGA CORPORATION, formerly known as Chattanooga Pharmacal Company, a corporation organized and existing under the laws of the State of Delaware, United States of America, of Post Office Box 4287, Chattanooga, Tennessee 37405, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement The present invention relates to a portable cooling apparatus and, more particularly, to a portable apparatus for cooling a limb or other body portion of a patient.

In U.S. Patent specification No. 3,916,911, there is disclosed a portable heating and cooling apparatus utilizing flexible pads to be wrapped around the limb or other body portion of a human or animal, for selectively heating or cooling that body portion. The portable apparatus is especially useful in treating sprains, strains or other muscular injuries to athletes or race horses, as soon after the injury occurs as possible in order to rapidly reduce swelling, fever or the like to the injured area. Such a device obviates the inconvenient use of ice packs for treating such injuries or muscular diseases or inflammation.

In U.S Patent specification No. 4,026,299 there is further disclosed another device for both heating and cooling, selection being made by a reversing valve and utilizing at least one flexible pad and tubing as well as quick-connect couplings, between the apparatus and the cooling and heating pads.

The invention consists in a portable appartus for cooling a limb or other body portion of a patient, comprising a compressor, a condenser, expansion valve means, at least one flexible pad adapted to be wrapped around a limb or other body portion and including flexible tubing serving as an evaporator, an auxiliary evaporator, conduit means for circulating a refrigerant serially from said compressor to said condenser, expansion valve means, tubing, auxiliary evaporator and back to said compressor, a by-pass conduit operatively connected to said conduit means and extending from a point downstream of said compressor and upstream of said pad to a point downstream of said pad and upstream of said auxiliary evaporator, and by-pass valve means for selectively opening and closing said by-pass conduit and so that the refrigerant will flow concurrently through the by-pass conduit and through the flexible tubing of said pad when said by-pass conduit is open, whereby the temperature of said pad can be controlled by the opening and closing of said by-pass valve means.

The by-pass valve is preferably thermostatically operated, so that the pad temperature may be selected maintained automatically. A preferred embodiment includes a resistance heating element secured in the pad, for example adjacent the tubing so that when desired, the apparatus may be used to heat a patient's limb or body portion, whilst the refrigerant directing components are maintained inactive.

Another feature that may be incorporated in the apparatus is a positive pressure device comprising a supply line extending from the high pressure side of the compressor and to the auxiliary evaporator thereby by-passing the condenser and an expansion valve in the line for maintaining a selected refrigerant pressure in the tubing.

In order that the invention may be more readily understood, reference will now be made to the accompanying drawings, in which: Figure 1 is an illustration of the internal components of one embodiment of apparatus according to the invention, showing the by-pass pipe feature; Figure 2 is a view of an open flexible pad, cooling tube and resistive heating element; Figure 3 is an illustration of internal components of another embodiment of the invention; Figures 4 and 5 are schematic views illustrating alternative apparatus component embodiments in directing refrigerant flow; and Figure 6 shows a skin temperature probe for thermostatically controlling the cooling apparatus.

Referring to Figure 1 of the drawings, apparatus 10, which is enclosed in a case member is shown cut away in order to expose the apparatus components. Major components include a condenser 12 and cooperating fan 31 for directing air past the condenser coils and facilitating removal of heat from the condenser, to condense refrigerant or refrigerant composition therein. Compressor 14 for use in liquifying refrigerant compresses gaseous refrigerant directed from a conduit 36 leading from an auxiliary evaporator and accumulator unit 16. The latter includes a length of thermally conductive tubing, usually copper coils, for facilitating heat transfer to the refrigerant as it is returned from the cooling pad and the tubing. Conduit 38 directs refrigerant from the compressor 14 to the condenser 12.

Outlet conduits 32 and 34 direct refrigerant from the cooling pad and tubing to the auxiliary evaporator and accumulator 16 via conduit 27. From the condenser 12, conduit 20 directs refrigerant through dryer 22, into the two conduit segments 25 and 33, through capillary tubes 26 and 24 constituting expansion valve means, respectively, and to cooling pads and tubing via inlet conduits 23 and 29. The apparatus 10 shown is for use with two cooling pads, it being understood that where only one cooling pad is used, only one set of capillary tubes and outlet and inlet conduits is required.

Figure 2 illustrates the flexible pad utilized to be wrapped around a warm body portion to be cooled. The open pad shown has an outside flexible thermally insulating sheet 40, preferably composed of a rubber composition and having a fabric back layer, such material commonly being used for wet suits and the like. Such a rubber composition provides excellent heat insulation and at the same time is reasonably lightweight and easy to form to any desired shape around a limb or other body portion. Secured to the inside of the insulating sheet 40 is a flexible hose, conduit or tubing 46, disposed in a serpentine configuration, for directing refrigerant to and from the pad and which tubing may be removably secured by a plurality of straps 31. These straps may be secured to the inside insulating pad surface using snaps, buckles or the like, or preferably Velcro (Registered Trade Mark), a material in which one mating surface has a plurality of fabric loops while the opposite surface comprises small, flexible barbs or hooks for engaging the loops. Such material is described in further detail, for example, in U.S. Patent specifications 3,461,511 or 3,387,345. Regardless of the type of disengageable device used for securing the ends of straps 31, a plurality of such straps are located at selected positions on the interior surface of the insulating sheet 40 by which the flexible refrigerant directing tubing is secured to the sheet. The removable straps allow for removing the tubing from the pad where pad replacement is desired.

Moreover, because the cooling tubing is flexible, different shaped cooling pads may be used on different limbs or body portions.

Thus, the cooling tubing simply can be removed from one cooling pad and placed in another pad as desired.

An inner, flexible relatively non-thermally insulating sheet 42 is releasably secured to sheet 40 in overlying relationship by utilizing Velcro fasteners 49 and 39 or other means such as snaps, zippers and the like provided on the sheets 42, 40, respectively. Should non-insulating sheet 42 become soiled or worn it may be removed and washed or otherwise cleaned for sanitary purposes, or replaced. It will also be understood that this non-insulating sheet lies against the patient's skin so that the cold from the cooling tubing is readily directed to the patient's limb or warm body portion. Moreover, removal or disengagement of the non-insulating sheet exposes the tubing for repairs or replacement.

Additional features of the pad includes straps 37 also having snaps or Velcro closure means cooperating on the pad so that the pad simply may be wrapped around the patient and secured. Other features of such a pad are disclosed fully in aforesaid U.S. Patent specification No. 4,026,299.

Although only one flexible pad and cooling tubing are shown, it will again be understood that a plurality of such pads may be used, depending on the size of the apparatus, including the compressor and condenser. In utilizing the single pad shown, tubing end 47 would be connected to conduit 34 whereas tubing end 45 will be connected to conduit 29 of the apparatus shown in Figure 1. Thus, cold refrigerant will pass from inlet conduit 29 through the tubing in the cooling pad and return to the apparatus through outlet conduit 34 from which it will be directed via conduit 27 into the auxiliary evaporator 16. It is convenient to incorporate quick-connect couplings to allow for easy connection or disconnection between the pad or pads and apparatus. Such couplings are of the type referred to, for example, in U.S. Patent specification 2,823,048 and which couplings are conveniently incorporated on a top panel for the apparatus (not shown) and as further described in U.S. Patent specification no. 4,026,299.

The apparatus incorporates by-pass pipe and cooperating valve for maintaining selected pad cooling temperatures. Such a pipe 28 is shown in Figure 1 interconnecting conduits 20 and 27. A solenoid valve 30 opens and closes the pipe 28. When the valve opens the pipe, refrigerant will pass through the pipe into conduit 27 and auxiliary evaporator and accumulator 16 thereby by-passing dryer 22, capillary tubes 24 and 26 and the cooling pad or pads and tubing.

Instead, the cooled refrigerant is directed to the auxiliary evaporator and circulates through the apparatus without further cooling the pad and flexible tubing. Actually, as refrigerant flows into conduit 27, this causes a back pressure to build up in the pads and tubing which concomitantly elevates the pad temperature. Preferably the valve 30 which cooperates with by-pass 28 and which opens and closes the by-pass pipe, is responsive to a thermostat control. A thermostat will monitor temperature at the cooling pad and when the pad temperature rises above a selected temperature the valve closes the by-pass pipe thereby directing the cooled refrigerant through the tubing at the cooling pad. When the pad has again cooled to the selected temperature, the sensing thermostat will cause the by-pass valve to open, whereupon refrigerant by-passes the pad. Preferably, the thermostat control will include a temperature selecting member such as a selector control and thermometer scale located on the apparatus control panel, as shown in Figure 6 and illustrated in U.S.

Patent specification No. 4,026,299. Accordingly, the desired pad temperature can simply be dialed or otherwise selected and the apparatus, when functioning, will maintain the selected temperature at the cooling pad, again, by periodically opening and closing the by-pass pipe.

Figure 3 illustrates an alternative embodiment of by-pass pipe and valve when utilizing an expansion valve 72 instead of the capillary tubes 24, 26 shown in Figure 1. For some applications it may be preferred to use an expansion valve since such a valve incorporates means for manually adjusting minimum pad temperatures. Moreover, the use of an expansion valve also allows the incorporation of a receiver or reservoir for storing additional refrigerant for automatically compensating for any refrigerenat losses during operation of the apparatus. The use of such a receiver or reservoir thus eliminates the necessity for charging refrigereant to the apparatus in case of minor leakage which may occur throughout the conduit and tubing system, especially where rubber tubing is used in the flexible cooling pads. It will be understood that such rubber tubing normally has some inherent porosity, thus causing some loss of refrigerant during normal usage.

Referring specifically to Figure 3, conduit portion 80 receives refrigerant from condenser 12 where it passes through dryer 75, conduit 82 and into expansion valve 72.

From the expansion valve, the refrigerant then passes to the cooling pads (not shown) via inlet conduits 23 and 29. Expansion valve 72 incorporates a manual knob 72 so that an operator may select or vary the extent of expansion in the valve and concomitantly the temperature characteristics of the cooling pad. Between conduits 80 and 82 also is located receiver or refrigerant reservoir 70 which holds a supply of refrigerant, forexample, about 16 ounces. A sight glass 71 may also be present for observing refrigerant flow and any bubbles or other indications of low refrigerant in the system as it passes the glass.

In the embodiment shown in Figure 3, the by-pass pipe or conduit 88 intersects conduit 38 between compressor 14 and condenser 12 rather than in the mode illustrated in Figure 1. The reason for by-passing the condenser in the embodiment illustrated in Figure 3 is due to the fact that when utilizing an expansion valve and receiver or reservoir in the apparatus, there may be more liquid refrigerant delivered to the auxiliary evaporator in the by-pass mode than it can handle. This is not a problem when the apparatus utilizes the capillary tubes and is without a refrigerant reservoir as shown in Figure 1. However, because it is a potential problem when utilizing the arrangement of Figure 3, it is preferred to divert the refrigerant during by-pass to the auxiliary evaporator from the high pressure side of the compressor prior to condensation in the condenser.

Otherwise, the apparatus illustrated in Figure 3 operates much like that shown in Figure 1.

When the cooling pad has been cooled to the desired temperature, the thermostat sensor will actuate solenoid valve 30 which will open conduit 88 thereby allowing the refrigerant to pass to conduit 27 and into auxiliary evaporator 16 and thereby by-passing condenser 12, expansion valve 72, and the cooling pads.

In still another embodiment, a positive pressure device may be incorporated to maintain a minimum pressure in the pad or pads and tubing. Thus, this feature is desirable in order to avoid a possible vacuum in the cooling pad tubing. Since this flexible tubing may consist of rubber or synthetic elastomer, which may be slightly porous, if a vacuum were to occur because of insufficient refrigerant in the system, air would be taken into the tubing and passed through the system which could cause contamination as well as damage to the compressor. In order to avoid such a situation, a positive pressure device consisting of a conduit and a manually regulated expansion valve are used.

Such a feature is illustrated further in Figure 3, although it must be appreciated that it can also be used with the apparatus shown in Figure 1 as well (see Figure 4). The positive pressure device consists of a supply line or conduit 89 which taps or communi cates with conduit 38 on the compressor high pressure side. The supply line extends to expansion valve 61 and supply line 85 communicates with expansion valve 61 and thus supply line 85 communicates with conduit 27 which then enters auxiliary evaporator 16. Expansion valve 61 may be adjusted by an operator utilizing manual adjustment knob 87 so that when the pressure in the system falls to or below a selected minimum pressure to which expansion valve 61 has been set, for example, 1-2 psi., it will cause the valve to open thereby directing the refrigerant from conduit 38 into line 89, expansion valve 61, line 85, conduit 27 and into the auxiliary evaporator.

This flow of refrigerant will continue until such time as the pressure in the system has again exceeded the minimum pressure. Thus, by so directing the refrigerant, it will cause a back pressure to be created in the pad tubing and will prevent the creation of possible vacuum in the cooling pad tubing. It will also be noted in Figure 3, that supply line 89 intersects or communicates with conduit 38 upstream of by-pass pipe 88. Again this positive system may be used even without a by-pass system so long as an auxiliary evaporator is present. The auxiliary evaporator functions as an accumulator in the cooling apparatus which function will be well understood to those skilled in the art. Thus, the auxiliary evaporator also acting as an accumulator insures that no liquid refrigerant is passed on to foul the compressor.

As will be seen from Figures 1 and 3, the auxiliary evaporator 16 is positioned with respect to that portion of the conduit system between the compressor 14 and pad so that there is substantially no heat exchange therebetween. In both embodiments the auxiliary evaporator 16 is positioned immediately adjacent the compressor 14.

Referring again to Figure 2, the use of a resistive heating wire or coil is illustrated.

The purpose for such an embodiment is to provide the apparatus with a heating capability separate and distinct from the refrigerant cooling operation previously described. Thus, there is incorporated a resistive heating wire element 44 conveniently placed alongside or otherwise adjacent the tubing 46 within the cooling pad utilizing the same securing straps 31. The ends 41 and 43 of the heating wire are shown and these will be secured properly to a switching member whereby a current will be supplied simply by flipping an on-off switch on the apparatus control panel. Normally, such a heating function will not be used when the pad is to be used for cooling a warm body portion.

Instead, when the compressor and other refrigerant cooling components are not operating, the pad simply may be used for providing heat to a patient where injury dictates that heat be applied instead of coolihg. It will be understood that the resistive heating wire will be insulated and of the type that can be safely incorporated adjacent the flexible cooling tubing and secured in a flexible pad of the type shown in Figure 2 and previously described.

Referring now to Figures 4 and 5, there is shown schematically apparatus including the conduits for directing refrigerant and the cooling pad 64 having the flexible tubing therein and which pad and tubing are to be wrapped around a warm body portion to be cooled. It will be appreciated that the pad and tubing act as an evaporator for the refrigerant. Figure 4 illustrates the appartus shown in Figure 1 with the addition of a positive pressure device embodiment, while Figure 5 illustrates the apparatus of Figure 3. Referring first to the Figure 4 apparatus, refrigerant is directed via conduit A to auxiliary evaporator 52 where it absorbs further energy by being heated.

Again, the auxiliary evaporator also serves as an accumulator. The refrigerant leaves auxiliary evaporator 52 via conduit B any enters compressor 51. Thereafter, the refrigerant is forced via conduit C into condenser 55 where it is cooled as it passes through the condenser coils and which cooling is aided by fan 56 which directs relatively cool ambient air over fine normally associated with the condenser coils. From the condenser, the refrigerant is directed along conduit D. Where pad 64 is to be cooled, the refrigerant is directed through dryer 62 where desiccant removes any moisture. Normally the dryer will also preferably include a filter or strainer, for example, a 100 mesh screeen, so as to prevent any particulate matter from entering capillary tube 63 via conduit E. Thereafter, the cooled refrigerant is directed to the pad via conduit F. When the pad has attained a suitably low temperature selected by an operator, a thermostat sensing the pad tempeerature electrically energizes solenoid valve 57 which valve opens conduit G and the refrigerant by-passes the dryer 62, capillary tube 63 and cooling 64 and is directed to conduit A and again to the auxiliary evaporator 52.

This refrigerant flow path is maintained until cooling pad 64 has become warm enough to require further cooling which condition is again sensed by a thermostat which energizes solenoid valve 57 and then closes by-pass pipe G.

In addition to the above discussed components regarding Figure 4, the positive pressure device is a line or conduit 11 which communicates with conduit C downstream of condenser 55 but upstream of compressor 51 and an expansion valve 61, which may be adjusted to maintain any desirable minimum pressure in the system as previously described.

Supply line J then directs refrigerant from the expansion valve to conduit A and auxiliary evaporator 52.

Figure 5 shows schematically the apparatus of Figure 3 whereby refrigerant travels in the manner described regarding Figure 4 with the major difference being that this embodiment incorporates a receiver or reservoir 70 for refrigerant for suppling refrigerant to the refrigerant-circulating conduit means and expansion valve 72 in place of capillary tubes. The receiver includes a dryer 75 and may also incorporate a window 71 for observing refrigerant flow in the conduit. When pad 64 is to be cooled refrigerant travels from compressor 51 via conduit C through condenser 55, through conduits D and E and into expansion valve 72, through conduit F and cooling pad 64, through conduit A into auxiliary evaporator 52 and back to compressor 51 via conduit B.

Once the cooling pad has achieved the desired low temperature, upon command from a sens- ing thermostat, valve 57 will open whereby refrigerant will pass from compressor 51 through conduits L, G, A, auxiliary evapor ator 52 and back to compressor 51 via con duit B. This condition will continue until further cooling of cooling pad 64 is required whereupon valve 57 will close and the re frigerant will then be directed as previously described. Again, the incorporation of a positive pressure device comprising con duits H and J, and a manually adjustable expansion valve 61 may be used. It should be appreciated that the positive pressure device may be used with or without the by pass lines described so long as an auxiliary evaporator is present in the apparatus.

As previously mentioned, it is desirable to thermostatically operate the cooling appar atus by sensing the pad temperature. Fig ure 2 illustrates a temperature sensing probe 84 secured to the pad insulated sheet 40 adjacent the cooling tubes so that the pad temperature is monitored and the by-pass pipe in the apparatus is automatically, opened and closed in response to the moni tored temperature. Probe 84 is secured at the end of insulated conductive wire 83 and dis connecting plug 87 which may be attached to a pIug and wire leading to the apparatus control panel. Thus, the temperature probe may be moved with the pad or independently replaced or repaired.

Figure 6 shows the use of a probe 94 and wire 96 for sensing the skin temperature rather than pad temperature. This feature is especially desirable when treating a patient wearing a cast 92 as is illustrated. For exam ple, it may be desirable to reduce swelling of a limb on which a cast is located. Yet, since a cast, usually plaster is itself thermally insulating, temperature selection and main tenance will be different than when the pad is directly applied to a limb. It may be necessary to maintain pad temperature at 20 A0 F. in order to achieve and hold skin temperature of 60"F., and this will vary with the cast thickness and composition.

Accordingly, it is highly desirable and advantageous to insert a temperature sensing probe 94 between cast 92 and the patient's skin. Cooling pad 90 will supply cooling to the cast in response to the temperature sensing probe, which will open and close electronic switching means for actuating the by-pass pipe valve feature of the apparatus in the manner previously explained. Conveniently a temperature scale on control panel 95 will be indexed for a desirable temperature range and a temperature selection control 98 will then be set to the specific temperature to be monitored by the probe and maintained by the by-pass valve feature. Such skin temperature selection is also very desirable for patients who are quite sensitive to cold and have low cold exposure tolerance. Thus, the cold temperature selection and maintenance feature is a highly advantageous feature made possible by the by-pass valve and pipe and auxiliary evaporator components.

The type of temperature probes used for skin or pad temperature monitoring is not critical. State of the art devices include temperature sensitive materials and cooperating resistors, etc., usually sealed in a hard resin cover. Conveniently the skin probe cover may have a flat side or sides for lying against the patient's skin and of a thickness suitable for sliding between the skin and a cast.

Again, it will be further understood by those skilled in the art that the pad by-pass features disclosed herein do not actually result in completely by-passing or isolating the cooling pads and tubing. Instead, when the by-pass pipe or the positive pressure expansion valve are opened, the flow of refrigerant therein causes a back pressure in the pad or pads as some refrigerant will continue to be to the pads and because of significant refrigerant flow into the conduit between the pads and auxiliary evaporator.

In either case, this will cause increased pressure in the pads and concomitant temperature increase.

The apparatus is preferably enclosed in a case, such as a portable carrying case as disclosed in U.S. Patent specification No.

4,026,299. Again, different sized and shaped cooling pads may be used as may means for injecting make-up refrigerant in the disclosed apparatus as described in Patent specification No. 4,026,299. Although the cooling pad has been described as used with flexible tubing, normally of a rubber or synthetic elastomer type, it is also within the scope of the invention to use any tubing which may be secured to the cooling pad to be wrapped around a warm body portion to be cooled. For example, a ductile copper tubing as disclosed in U.S. Patent specification No. 4,026,299 may be used.

WHAT WE CLAIM IS: 1. A portable apparatus for cooling a limb or other body portion of a patient, comprising a compressor, a condenser, expansion valve means, at least one flexible pad adapted to be wrapped around a limb or other body portion and including flexible tubing serving as an evaporator, an auxiliary evaporator, conduit means for circulating a refrigerant serially from said compressor to said condenser, expansion valve means, tubing, auxiliary evaporator and back to said compressor, a by-pass conduit operatively connected to said conduit means and extending from a point downstream of said compressor and upstream of said pad to a point downstream of said pad and upstream of said auxiliary evaporator, and by-pass valve means for selectively opening and closing said by-pass conduit and so that the refrigerant will flow concurrently through the by-pass conduit and through the flexible tubing of said pad when said by-pass conduit is open, whereby the temperature of said pad can be controlled by the opening and closing of said by-pass valve means.

2. Apparatus as claimed in claim 1, wherein said by-pass valve means includes means for monitoring the temperature at said pad, and means for closing said by-pass valve means when the temperature at the pad is above a preselected temperature, and for opening said by-pass valve means when the temperature at the pad is below a preselected temperature.

3. Apparatus as claimed in claim 2, wherein said temperature monitoring means comprises a temperature sensing probe secured to said pad.

4. Apparatus as claimed in any of claims 1 to 3, wherein said expansion valve means comprises a capillary tube, and wherein said by-pass conduit extends from a point downstream of said condenser and upstream from said capillary tube to said auxiliary evaporator.

5. Apparatus as claimed in any of claims 1 to 3, wherein said expansion valve means comprises an expansion valve, and wherein said by-pass conduit extends from a point downstream from said compressor and upstream from said condenser to said auxiliary evaporator.

6. Apparatus as claimed in claim 5, including a refrigerant reservoir communicating with said conduit means upstream of said expansion valve for supplying refrigerant to the refrigerant-circulating conduit means.

7. Apparatus as claimed in any of claims 1 to 6, including positive pressure means for maintaining a selected refrigerant minimum pressure in said tubing, said positive pressure means comprising a supply line communicating with said conduit means downstream of said compressor and extending to said auxiliary evaporator, and valve means in said supply line.

8. Apparatus as claimed in any of claims 1 to 7, wherein said pad includes a resistive heating element to permit the heating thereof.

9. Apparatus as claimed in any of claims 1 to 8, including a fan operatively associated with said condenser for facilitating the removal of heat therefrom.

10. Apparatus as claimed in any of claims 1 to 9, wherein said pad includes a flexible thermally insulating outer sheet, a flexible inner sheet, and means for releasably interconnecting said outer and inner sheets in an overlying relationship and with flexible tubing disposed therebetween.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. which may be secured to the cooling pad to be wrapped around a warm body portion to be cooled. For example, a ductile copper tubing as disclosed in U.S. Patent specification No. 4,026,299 may be used. WHAT WE CLAIM IS:

1. A portable apparatus for cooling a limb or other body portion of a patient, comprising a compressor, a condenser, expansion valve means, at least one flexible pad adapted to be wrapped around a limb or other body portion and including flexible tubing serving as an evaporator, an auxiliary evaporator, conduit means for circulating a refrigerant serially from said compressor to said condenser, expansion valve means, tubing, auxiliary evaporator and back to said compressor, a by-pass conduit operatively connected to said conduit means and extending from a point downstream of said compressor and upstream of said pad to a point downstream of said pad and upstream of said auxiliary evaporator, and by-pass valve means for selectively opening and closing said by-pass conduit and so that the refrigerant will flow concurrently through the by-pass conduit and through the flexible tubing of said pad when said by-pass conduit is open, whereby the temperature of said pad can be controlled by the opening and closing of said by-pass valve means.

11. Apparatus as claimed in claim 10, wherein said pad further comprises means for releasably holding it in a wrapped position around the limb or body portion.

12. Apparatus as claimed in claim 10 or 11, wherein said flexible tubing is disposed in a serpentine configuration and is releasably secured to said outer sheet.

13. Apparatus as claimed in any of claims 1 to 12, wherein said auxiliary evaporator is positioned with respect to that portion of said conduit means between said compressor and pad so that there is substantially no heat exchange therebetween.

14. Apparatus as claimed in claim 13, wherein said auxiliary evaporator is positioned immediately adjacent said compressor.

15. A portable apparatus substantially as hereinbefore described with reference to Figures 1 and 2 of the accompanying drawings.

16. Apparatus as claimed in claim 15, modified substantially as hereinbefore described with reference to Figure 4 of the accompanying drawings.

17. A portable apparatus substantially as hereinbefore described with reference to Figures 3 and 5 of the accompanying drawings.

18. Apparatus as claimed in any of claims 15 to 17, including a control panel substantially as hereinbefore described with reference to Figure 6 of the accompanying drawings.