The invention relates to a heat transfer device to be used in the repair of water pipes and intended for preventing the flow of liquid through a pipe and forming a part of a closed refrigeration system, the device forming an evaporator for a refrigerant.

It is previously known to block the passage of liquid (water) through the pipe by forming therein a temporary ice plug. The freezing has been effected by spraying a refrigerant, such as liquid freon, on the pipe. Amongst the drawbacks of this kind of solution is the high consumption of refrigerant as it has to be sprayed on the pipe continuously during the repair. Furthermore, the refrigerant may be conveyed into the environment thus damaging it, risking safety at work, and causing health hazards.

Attempts have been made to reduce such draw¬ backs using a device in which the refrigerant circu- lates in a space between the pipe to be refrigerated and the refrigeration means. One drawbac ^' is that the refrigerant is in direct contact with the pipe; on the other hand, rather complicated and, as a consequence, expensive solutions are required for ensuring the necessary sealing effect and reliable operation.

Moreover, devices have been developed in which the refrigerant is arranged to circulate partially or entirely around the pipe section to be refrigerated. These devices, however, are massive and complicated in structure as well as cumbersome and difficult to ar¬ range into working spots.

The object of the present invention is to pro¬ vide a device which avoids the above-mentioned draw¬ backs. A further object is to provide a device which , can be adapted to pipes of different sizes and which

is easy to arrange into working spots difficult to reach. This is achieved by means of a device according to the invention, which is characterized in that the device is provided with a groove adapted for at least one pipe size and shape.

The invention is based on the idea that there is provided around the pipe section to be refrigerated a closed refrigerant circuit, which is easy to fit tightly around the pipe section or a refrigerating me- dium circuit which is connected to a separate cooling medium circuit. As a consequence, the repair can be carried ^' out more rapidly, and adverse environmental effects are avoided; on the other hand, the device can be used in any environment. The device and its connec- tions are easy to construct using existing convention¬ al refrigerating units.

In the following the invention will be de¬ scribed by way of example and in more detail with re¬ ference to the attached drawings, wherein Figure 1 shows a heat transfer device com¬ prising preformed grooves for different pipes sizes and shapes;

Figure 2 shows a heat transfer device com¬ prising two parts movable in parallel with respect to each other on a slide;

Figure 3 shows a heat transfer device provided with a straining strap;

Figure 4 shows a heat transfer device com¬ prising two jacket portions hinged on to each other; and

Figure 5 shows a heat transfer device com¬ prising a flexible jacket connected to a separate cooling circuit.

The heat transfer device of Figure 1 comprises two evaporation chambers 1 and 2 which are hinged on

to each other by a flexible tube 4. The tube, and the refrigerant flowing therethrough, is arranged to first go into one chamber 1 and out of it through the end * facing the pipe; then it returns to the other end of

5 the same chamber along the outer surface thereof. In this end the tube forms a spiral providing a hinge ef¬ fect. The tube goes further along the outer surface of the other chamber 2 and into said chamber through one end thereof and further out of it from the other end. 10 The tube ends are connected to a supply and return tube 5 and 6, respectively, of a refrigerating unit 7. The chambers are provided with grooves 8 for pipes of different sizes and shapes. The grooves can f rther be provided with thermally conductive fitting parts 9. 15 The chambers can be tightened with respect to each ^• other by means of screws 3.

The heat transfer device of Figure 2 comprises two evaporation chambers 11 and 12 movable with re¬ spect to each other on a slide (not shown) . Refriger- 20 ant tubes 4a, 4b are connected to the refrigerant cir¬ cuit as described above. The flow of the refrigerant is arranged to take place either through both chambers (A) or through one chamber only (B) . A groove 18 pro¬ vided in the chambers 11 and 12 for the pipe to be re- 25 frigerated may also comprise thermally conductive fitting parts for different pipe sizes and shapes.

The embodiment of Figure 3 comprises a single ^• evaporation chamber 21 through which the refrigerant flow is arranged to take place. The tubes 4a„, 4b are _s 30 connected to the refrigerant circuit as described above. The device is intended to be fitted around the > pip® "to be refrigerated by means of a thermally con¬ ductive straining strap 22. The strap is strained by means of latch means 23. Various thermally conductive 35 fitting parts 29 can be used between the chamber 21

and the pipe. Naturally, the end face of the chamber can also be formed according to a pipe.

The heat transfer device of Figure 4 is formed by two jacket portions 31 and 32 hinged on to each other and acting as an evaporator. The jacket portions correspond to the pipe to be refrigerated in shape so that they together enclose the pipe. The flow of the refrigerant is arranged through the tube 4a into the first jacket portion 31, where it is passed on by guide ribs 34, and further through a connecting tube 33 into the second jacket portion 32, wherefrom it is discharged through the tube 4b. The jacket portions can be provided with evacuating means. The above-men¬ tioned refrigerant circuit is connected to the tubes 4a and 4b. Such a structure is intended primarily for large pipes.

The heat transfer device of Figure 5 is formed by a jacket 41 made of a flexible material such as plastic. Liquid guide ribs 44 are provided within said jacket. The jacket can be fitted tightly around the pipe to be refrigerated and fixed by a sticker or a fixing spring, for instance.- The ^' jacket 41 forms part of a separate closed ^■ heat ^• transfer circuit A which is connected via a heat exchanger (evaporator) B to a separate closed cooling medium circuit (freon) C known per se. In the heat transfer circuit the heat transfer liquid may be glycol or a mixture of water and alcohol which do not freeze at temperatures oc¬ curring during the repair. The circulation of the li- quid can be effected by a pump P, such as a piston pump or a gear-type pump.

In place of a jacket it is likewise possible to use a double hose connected at the bending point thereof by a U-shaped part. The hose can be corre- spondingly fitted around the pipe to be refrigerated

and fixed e.g. with a sticker or a tension spring.

Both the jacket and the hose can be coated with a material having poor adhesive properties for improv¬ ing adherence and adaptability (heat transfer) . Corre- spondingly, they can be insulated for improving effi¬ ciency.

It is obvious that the separate cooling medium circuit and heat transfer circuit described in connec¬ tion with Figure 5 can be applied also in connection with the other embodiments. It is likewise possible in connection with the different embodiments to use in¬ sulation and an agent, such as grease or the like, promoting heat transfer between the pipe'to be refri¬ gerated and the heat transfer device. The heat trans- fer device can also be applied elsewhere than on pipes.

The drawings and the description related there¬ to are only intended to illustrate the idea of the in¬ vention. In its details, the device according to the invention may vary within the scope of the attached claims.