DE9016548U1 - Calender roll - Google Patents

Description

Attorney file: P 4761

Password: "Paraffin zone roller"

J.M. VOITH GmbH

Calender roll

The invention relates to a calender roll, in particular for machines for producing or processing paper, cardboard or plastic film webs. As is known, for example, from US-PS 4,738,196, such calender rolls are combined with a device for thermally influencing the outer surface of the calender roll in zones. In other words, this means: the roll shell is divided into numerous, relatively narrow zones over its length (i.e. over the width of the web to be treated). Each of these zones can be thermally influenced individually, i.e. heated or cooled, so that the diameter of each zone can be increased or reduced by a small amount relative to the diameter of the neighboring zones. This makes it possible to correct the thickness of the web to be treated in individual zones. As a rule, a web with a thickness cross-profile that is as even as possible is desired.

The device mentioned for thermally influencing the roller malt shell in zones includes, for example (according to US-PS 4, 738, 196), an air jet nozzle for each zone. The use of infrared radiators or devices for generating an eddy current can also be considered. All of these devices are usually located outside the roller, i.e. on its periphery. However, it is also possible to provide an electrical heating device for each zone inside the roller.

1214T/93-95

The invention is based on the object of improving the known calender rolls of the type described above in such a way that the energy expenditure required for a certain diameter change in a zone of the roll shell is reduced.

This object is achieved by applying the characterizing features of claim 1. The material with an extremely high coefficient of thermal expansion provided in each ring channel ensures that, for example, when heat is supplied to the relevant zone, a relatively large expansion of the roll shell in the relevant zone is achieved with a relatively low expenditure of thermal energy.

If heat is supplied to the relevant zone from the outside (preferred embodiment of the invention), then initially as before, an increase in diameter occurs due to thermal expansion of the outer shell, but then additionally an increase in diameter due to the thermal expansion of the material filling the ring channel.

Further embodiments of the invention and an embodiment are explained below with reference to the drawing.

Figure 1 shows a partial longitudinal section through a calender roll.

Figure 2 shows a schematic perspective view of the calender roll and an associated blow box.

The calender roll, designated as a whole by 10 in Figure 1, has an inner main roll body 11, with a bearing journal 11a. The main roll body 11, which is preferably made of cast steel, has in its outer surface numerous ring channels 12 evenly distributed over the length, which are incorporated into the main roll body and which are covered by an outer shell 3, preferably made of steel. The outer shell can, as

shown by way of example in Figure 1, be composed of several rings (3 ¹ , 3*', 3 ¹¹¹ etc.). According to Figure 1, a ring (as part of the outer casing 3) is assigned to each ring channel 12 and is welded to the main roller body 11. Such rings can also be shrunk onto the main roller body 11. In this case, rings of greater length can be provided, with each individual ring covering several ring channels.

For each ring channel 12, a radial bore is provided in the outer casing 3, as shown by way of example at 16 in Figure 1. Through this bore, the ring channel is filled with a material, e.g. paraffin, wax or the like, whose coefficient of thermal expansion is significantly greater than that of steel, i.e. the material from which the main roller body 11 and the outer casing 3 (composed of the rings) are made. It goes without saying that in addition to the filling bore 16 shown, there is a venting bore, and that both bores are closed after filling. Alternatively, each ring channel 12 can be filled with a metal alloy before the outer casing is shrunk or welded on, e.g. using aluminum and/or magnesium, whose coefficient of thermal expansion is approximately two to three times higher than that of steel.

From Figure 2 it can be seen that the calender roll 10 can be assigned, for example, an external air blow box 17 which has at least one air blow nozzle 18 for each zone, i.e. for each ring channel 12, with which heated or cooled air can be blown onto the outer casing 3 of the calender roll 10.

03.12.90
DSh

Claims (8)

Attorney file: P 4761 Keyword: "Paraffin zone roller" J. M. VOITH GmbH Protection claims 1. Calender roll (10), in particular for machines for producing or processing paper, cardboard or plastic film webs, with a device (17, 13) for thermally influencing (heating or cooling) the outer surface of the calender roll in zones (i.e. varying across the web width), characterized by the following features: (a) Each zone is assigned an annular channel (12) inside the rollers that is hermetically sealed to the outside. (b) Each ring channel (12) is filled with a material (e.g. paraffin) whose coefficient of thermal expansion is significantly (i.e. at least 2 to 10 times) greater than that of the roller material. Fig. 1. 2. Calender roll according to claim 1, characterized in that the material filling the ring channels (12) is paraffin. 3. Calender roll according to claim 1, characterized in that the material filling the ring channels (12) is an organic compound, e.g. a wax. 1214T/91-92 4. Calender roll according to claim 1, characterized in that the material filling the ring channels (12) is a metal or a metal alloy, e.g. aluminum or magnesium. 5. Calender roll according to one of the preceding claims, characterized in that the annular channels (12), as known per se, are arranged between an inner roll main body (11) and an outer shell (3). 6. Calender roll according to claim 5, characterized in that the ring channels are provided on the inside of the outer shell. · 7. Calender roll according to claim 5, characterized in that the annular channels (12) are arranged on the outside of the roll main body (11). 8. Calender roll according to claim 7, characterized in that the outer shell (3) is composed of individual rings (3 ¹ , 3 ¹¹ , 3 ¹ ' ¹ ) which are connected to the roll main body (11) by shrinking or by welding.