The plates of plate heat exchangers are manufactured by the cold working method by pressing one plate at a time between plane tools. One of the tools is used as a press and the other as a die. The degree of deformation of the plate parts to be manufactured depends on the height and shape of the profile of the plate to be manufactured. The profiles of plates in heat exchangers are normally so low that the degree of deformation does not cause problems. With an increase in the plate size, however, the need for compressive force becomes so great that a small engineering workshop manufacturing plate heat exchangers does not have the economical resources to purchase a press required for pressing the plates. For pressing smaller plates, a mechanical eccentric-type press has been sufficient, whereas larger plate parts have normally been pressed with hydraulic presses.

Plane tools used for the manufacture of plate parts are very heavy, due to the great forces. The manufacturing costs of such tools are so high that it is not economical to make small quantities of plates. Separate tools are required for cutting the plate parts. The force required by cutting of the plate parts is normally smaller than the force required by working, wherein lighter presses can be used for cutting. Holes are made in the plate parts to be used in plate heat exchangers by means of punching tools. The conventional manufacture of plate parts for a heat exchanger comprises several work stages, starting from the cutting of a continuous sheeting to blanks of suitable size and ending e. g. in the punching of holes.

Previously known is also the manufacture of various profiled metal plates by the rolling method. Profiling is used in the plates either for reasons of appearance or to reinforce the plate. Roofing sheets shaped by section rolling may be the best- known products of this type. In such roofing sheets made of thin sheets, the degree of deformation is normally so high that the rolling is made in several steps. Profiling cuttings are not made in roofing sheets by machine, but the sheets are cut in particular areas with separate cutting edges. Shaping by rolling is used in the manufacture of long laths or profiled pieces. Also an edging press can be used to make various profiles in the plates. It is common to the above-mentioned methods that the profiling tools are not used for cutting of the plate.

The purpose of the present invention is a method and a device for shaping and cutting a plate part in one working step between two rolls, wherein the plate part is finished after it has travelled through a pair of rolls. The invention is based on the idea that the outer edges of the plate heat exchanger and the outer edges of the holes are even planes, wherein they are easier to cut in connection with the rolling than profiled portions.

More precisely, the method and device for manufacturing plate parts according to the invention are characterized in what will be presented in the claims to follow.

In the method for manufacturing plate parts, the plate parts are shaped between two rolls with opposite shapes and are cut off to their final shape simultaneously when they are being shaped. The distance of the rolls does not affect the synchronization of the rolls, because the rolls are coupled to each other with a gearing fitted at one end of the rolls and being adjusted with or without a clearance. The synchronization of the rolls is arranged with roll-specific synchronization motors or servomotors and with an electrical control system. The height of the profile pattern of the plate parts to be manufactured can be changed by changing the height of the rolls. The cutting edges of the rolls are either

worked on the surface of the rolls in a stationary manner, or detachable, wherein they can be changed. The cutting edges are preferably sharpened when they are attached to the rolls. The profiling patterns having opposite shapes on the surfaces of the rolls are either fixed to the surfaces of the rolls in a stationary manner, or detachable, locked onto the surfaces of the rolls in a stationary manner. The distance of the rolls is adjusted with vertical posts of the frame part, cut for this purpose.

The method and device for manufacturing plate parts according to the invention has considerable advantages to methods and devices presently in use. Particularly in the manufacture of larger plate parts, the pressing force required is substantially reduced when compared with planar working tools. The supply price of a roll suitable for manufacturing plates for a heat exchanger is only a fraction of the supply price of a large hydraulic press. The method and device for manufacturing plate parts according to the invention considerably reduce the manufacturing costs of larger plate parts with low profiles. The plate part is made with one tool during one working step, wherein there is no need for intermediate storages or synchronization of machines implementing different steps in the production line. The quality of the plate parts to be manufactured is improved, because there are no production tolerances between different working steps.

In the following, the invention will be described in more detail by means of one embodiment and with reference to the appended drawings.

Figure 1 shows one embodiment of the device for manufacturing plate parts according to the invention.

Figure 2 shows rolls of the device according to Fig. 1 in a cross-section at the end of the gearing.

In the method according to the invention, the plate parts are manufactured with a device of Fig. 1, in which rolls 2 and 3 are mounted on bearings in a frame part 1 to be supported by vertical posts 4 and 5. The vertical posts 4 and 5 can be protected with housings 6 and 7. Figure 1 shows how plate parts 9 are shaped of a continuous sheeting used as the raw material between the rolls 2 and 3. In view of the working technique, it is advantageous to make the profiling of the heat exchanger plates in the running direction of the sheeting 8, transverse to the rolls 2 and 3. The locations of holes 10 in the plate parts 9 for the heat exchanger determine the magnitude of the brush angle which is a decisive factor in the heat exchanger in view of its thermal and flow technical properties. The brush angle is the angle between the brushes or flutes of two opposite plate parts. In the method of the invention, the plate parts 9 are cut off the sheeting 8, and the holes 10 are made simultaneously between the rolls 2 and 3. The force required by the rolling is considerably smaller than when using planar pressing tools. This smaller need for force is based on the fact that the contact surface between the rolls 2 and 3 and the sheeting 8 is, in principle, a line, wherein the area to be worked is small.

At one end of the rolls 2 and 3, there is a gearing 11 which is typically without a clearance, wherein the rotary movements of the rolls 2 and 3 are locked in relation to each other, which is very important, particularly when plate parts 9 are cut off from the sheeting 8. In the embodiment of the invention shown in Fig. 1, the gearing 11 consists of two cogged wheels 12 and 13 coupled to each other, one of them being divided into three parts which can be rotated in relation to each other. When the distance between the rolls 2 and 3 is changed, the clearance formed between the cogged wheels 12 and 13 is eliminated by rotating the parts of the three-part cogged wheel 13 in such a position that there is no clearance left.

In addition to mechanical synchronization of the gearing 11 by a gear transmission without a clearance, the rotation of the rolls in relation to each other is controlled electrically by means of a control centre 14. Both of the rolls 2 and 3

have separate driving mechanisms which in the embodiment of Fig. 1 comprise electrical motors 15 and 16 as well as gearings 17 and 18. The synchronization of the rolls 2 and 3 can be implemented either mechanically, electrically or by using a combination of these.

The distance between the rolls 2 and 3 can be adjusted by fitting shims 21 of desired size in holes 20 in the vertical posts 4 and 5. The shims 21 are tightened in their position by means of bolts 22 extending through the gaps 20, and nuts 23, as can be seen in Fig. 2. It can be seen in the cross-sectional view of the rolls 2 and 3 in Fig. 2 that in this embodiment, the rolls 2 and 3 are made of tubes 21 and 22 having thick walls and forming the mantles of the rolls. At each end of the tubes 21 and 22, there are end pieces 23 and 24, through which the shafts 25 and 26 of the rolls 2 and 3 extend. The tubes 21,22 are coupled by means of their end pieces 23,24 to their shafts 25,26 in a fixed manner, either by welding or by attaching them to each other in a detachable manner.

In the embodiment of Fig. 2, the parts 27 and 28 profiling the plate parts 9 are worked directly onto the surfaces of the tubes 21 and 22 acting as mantles on the rolls 2 and 3. The profiling parts 27,28 can also be made as planar plates which are bent and fixed onto the surfaces of the rolls 2,3 in a stationary manner. With respect to the profiling technique, it is advantageous to extend the area to be profiled over the whole width of the sheeting 8 as shown in Fig. 2. In this case, also the parts of the sheeting 8 left outside the plate parts 9 can be used in the manufacture of smaller plate parts. The cogged wheels 12 and 13 are coupled as tooth wheel rims to the tubes 21,22 or the shafts 25,26. They can also be fixed to the end pieces 23,24 of the rolls 2,3.

In the embodiment of Fig. 2, the cutting edges of the outer edge of the plate part 9 consist of edges 29 and 30 attached to the rolls 2 and 3, of which edges one can be used as a dolly and the other as the cutting edge. It is also possible to

sharpen both of the edges to be cutting. The cutting edges 29,30, or one of them, can be made stationary on the surface of the mantles of the rolls 2,3, wherein e. g. only the cutting edge is changed as a result of sharpening and wearing. The cutting edges 29,30 must conform to the shape of the peripheries of the rolls 2,3 so that they can be fixed onto the surfaces of the rolls 2,3.

To make the holes 10 of the plate part 9, the rolls 2,3 are provided with cutting edges 31,32, either by working or by fixing. One of the cutting edges can be used as a press for cutting and the other can be used as a mating ring. The cutting edges 31,32 of the holes 10 can be either made of the material of the rolls 2,3, or fixed onto the surfaces of the rolls 2,3 in a detachable manner, as shown in Fig. 2.

The cutting edges 29,30,31 and 32 are preferably sharpened when they are fixed onto the surfaces of the rolls 2,3. When the sharpening of one of the cutting edges 29,30,31,32 is finished, the edge is detached and replaced by a new one, if it is a detachable edge. If the edge is a fixed part on the surface of the rolls 2,3, the operating life of a edge which is sharpened or worn out can be extended by welding or by corresponding methods.

The shafts 25,26 of the rolls 2,3 are mounted on bearings 33 fitted inside the vertical posts 4,5 forming the frame part 1. For rotating the rolls 2,3, at least one of the shafts of the rolls 2,3 is led through the vertical posts 4,5 to be coupled to an operating apparatus 17,18.

The method and device for manufacturing plate parts according to the invention are used in the following way. The distance of the rolls 2,3 is adjusted to comply with the thickness of the sheeting 8 used as the raw material, by placing suitable shims 21 in gaps 20 of the vertical posts 4 and 5 and by tightening the bolts 22 by means of the nuts 23. The gearing 11 is adjusted mechanically to have no

clearance by means of the three-part cogged wheel 13 and/or electrically by roll- specific synchronization motors or servomotors 15,16,17,18.

The control centre 14 is used to select a rotating speed corresponding to the material properties and the thickness of the sheeting 8 used as the raw material, and to feed the sheeting 8 to be worked between the rolls 2,3 which profile and cut the plate parts 9 simultaneously. To make the method and device for manufacturing plate parts of the above-mentioned kind work, a device is required to unwind the sheeting 8 which is e. g. on a reel, as well as roller tracks in front of and behind the rolls 2,3 for the purpose of feeding the sheeting 8 and removing the plate parts 9.

It is obvious for anyone skilled in the art that the above-presented description and the relating figures are only intended to illustrate the present invention. With respect to the details, the method and device for manufacturing plate parts can vary within the scope of protection of the appended claims. Thus, for example the adjustment of the distance between the rolls 2,3 can be easily automated by present techniques. The profiling parts 27,28 can be implemented in a way different from that presented above; similarly, there are previously known solutions for the manufacture, fixing and maintenance of the edge parts 29,30, 31,32.