JPH04306584A - Induction heat emitting roller device - Google Patents

Abstract

PURPOSE:To heat a thermal load uniformly by allowing a roller to accommodate jacket chambers, in which a two-phase thermo-medium in gaseous and liquid phases as creeping on the circumferential wall is encapsulated, and an induction heat emission mechanism which is swingable in the roller axis direction within a range wider than the width of the thermal load. CONSTITUTION:Inside of the circumferential wall of a roller, a plurality of mutually independent jacket chambers 5 are provided in the axial direction of the roller 1, and distilled water as a gas/liquid two-phase thermo-medium is encapsulated in each chamber 5. This roller 1 is supported rotatably on a machine frame 4 by a drive shaft 2 through bearing 3. An induction heat emission mechanism 6 is composed of an induction coil 10 and a Fe core 11, and the coil 10 is connected with the power supply through a lead 12. The chambers 5/mechanism 6 length in the axial direction of the roller 1 shall be equal to or smaller than the width of an thermal load 13, and the mechanism 6 is swung left and right by a supporting rod 7 and also an air cylinder 15 and piston 16 of a swinging mechanism 14, Thereby the thermal load 13 can be heated uniformly, and the temp. difference between thermally loaded and non-loaded ranges be lessened.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating roller device.

0002

BACKGROUND OF THE INVENTION In an induction heating roller device, an induction heating mechanism is installed inside a rotating hollow roller, and the peripheral wall of the roller generates Joule heat using an induced current.
It is already well known that the surface temperature of the roller is uniformed by sealing a gas-liquid two-phase heating medium in a gap provided in a thick portion of the peripheral wall of the roller.

By the way, when this type of roller device is used for drying, rolling, or heating steel plates or other metal plates in the paper manufacturing process, the amount of heat load is generally quite large. The treated product, which causes a heat load, can be considered to produce a heat-absorbing effect that is approximately evenly distributed over the entire width in contact with the treated product within a fixed working width within the surface length of the roller.

However, with both ends of the heat absorption width as boundaries,
a non-heat-absorbed area on the outer circumferential surface of the roller;
That is, since there are areas on both sides of the edges of the treated product that are not in contact with the treated product, the surface temperature of these areas tends to be higher than the temperature of the heat-absorbing width.

[0005] This tendency is exacerbated as the amount of heat load increases. Finally, the surface of the roller near both ends of the treated product begins to exhibit a steep temperature gradient. The occurrence of such a temperature gradient makes it difficult to achieve the objective of uniformly heating the treated product over its entire width.

[0006] In addition, if the application is to be applied to a rolling machine or the like in which a plurality of rollers are placed one on top of the other with their axes parallel to each other to generate nip pressure between each roller, another problem arises. occurs.

[0007] For example, thin processed products such as paper,
When passing the processed product between rollers under nip pressure, if the temperature near both ends of the roller is higher than the center, the difference in thermal expansion in the diametrical direction of the rollers corresponding to the temperature will cause the processed product to This causes an overpressure state, which impairs the high quality of the processed product.

[0008] Furthermore, the roller on the other side to be nipped is not a heat-generating roller, but has a surface made of material other than metal, such as rubber,
Made of elastic material such as plastic,
Or one coated with a material that has a relatively low heat resistance (
Hereinafter, it will simply be referred to as an elastic roller. ), the surface temperature of these elastic rollers in the area in contact with the treatment product is insulated by the treatment product and does not heat up as much.

However, the elastic roller in contact with the vicinity of both ends of the roller that does not contact the processed product receives heat directly from the heat generating roller, and as mentioned above, the vicinity of both ends of the roller is a high temperature area. Thermal deterioration occurs on the surface of the material, impairing its physical and mechanical properties. In extreme cases, the surface may burst during operation, causing an accident with scattering.

[0010] Such problems are further exacerbated if the surface length of the roller becomes larger than the width of the processed product. In other words, when processing several types of products with different widths using a roller with a constant surface length, the narrower the width of the product, the more noticeable the problems described above will occur.

Ideally, there should be little or no area at either end of the roller that is not removed by the product being treated. However, as mentioned above, this method cannot be used when processing products having different width dimensions, and it is not practical to eliminate the extra surface length at both ends of the roller as a practical problem in operation.

From the above point of view, in the past, the induction coil installed inside the roller is divided into a plurality of parts in the axial direction, and each part is made into an independent magnetic flux generating mechanism, so that both ends of the roller are not subjected to thermal load. Attempts have also been made to avoid high temperatures near both ends of the roller by appropriately reducing the input to the induction coils located near the ends.

[0013] Regarding rollers using heating methods other than induction heating rollers, a rotary joint for cooling is provided at the end of the drive shaft of the roller, and the refrigerant is forced to circulate only at both ends of the roller. It is also possible to cool the roller by spraying a mist of cooling water onto both ends of the outer peripheral surface of the roller from outside the roller.

Although these attempts have shown some success, they have not yet achieved a uniform temperature distribution or a uniform nip pressure over the entire width of the processed product. This is because it is still not possible to eliminate the steep temperature gradient at both ends of the processed product, or to overcome the problem of overpressure tendency and underpressure due to overcooling.

In other words, in the case of an induction heating roller, a heat equalizing effect is achieved by a heating medium sealed inside the peripheral wall of the roller. This soaking effect extends beyond the width of the processed product to the end areas of the roller. This is what hinders the solution of the problems mentioned above.

To explain the reason for this, when a jacket chamber in which a heating medium is enclosed is provided on the peripheral wall of the roller, it is desirable that the jacket chamber be provided at a position as close as possible to the outer peripheral surface of the roller. However, considering the load applied to the roller, a certain amount of remaining thickness must be ensured. Therefore, there is naturally a limit to reducing the thermal resistance in the radial direction of the roller from the wall surface of the jacket chamber in contact with the heating medium to the outer peripheral surface of the roller.

Even if the internal temperature of the jacket chamber is maintained at the same temperature in the area with and without heat load, the difference in heat flux from there to the outer peripheral surface of the roller varies between the two areas. This results in a temperature difference that appears on the roller surface. Therefore, as described above, even if induced heat generation is eliminated in areas corresponding to areas with no heat load, as long as there is a heat equalizing effect by the heating medium, the temperature in those areas will increase.

[0018]

[Problems to be Solved by the Invention] The present invention provides a structure in which a roller is provided with a jacket chamber, so that the heat equalizing effect of the heat medium sealed inside the jacket chamber acts only on the area where the heat load is present, and the heat is reduced. The purpose is to prevent the heat load from reaching both ends of the roller where no load exists, thereby avoiding the occurrence of a steep temperature gradient near the edge of the heat load.

[0019]

[Means for Solving the Problems] The present invention provides a jacket chamber that extends in the axial direction of the peripheral wall of the roller and seals a gas-liquid two-phase heating medium therein, and also provides a jacket chamber that is guided into the inside of the roller. A heating mechanism is provided, the length of the jacket chamber and the induction heating mechanism along the roller axis direction is equal to or shorter than the width of the thermal load of the roller, and the induction heating mechanism is
It is characterized in that it is installed so that it can swing freely along the axial direction of the roller within a range that is equal to or greater than the width of the thermal load.

[0020]

[Function] The length of the jacket chamber and induction heating mechanism is not set to exceed the width of the heat load, so the jacket chamber provides a uniform heat effect within the width of the heat load, and the surface of the roller where no heat load exists. Temperature increases in the area are thereby avoided.

However, in reality, in addition to heat removal due to heat load from the surface of the roller, there is a heat removal factor in the axial direction that is unique to the equipment in which the roller is incorporated, so it is necessary to avoid the tendency for the temperature in the no-load area to drop too much. I can't do it. The degree of this does not remain constant, depending on the operating conditions such as the magnitude of the heat load and the symmetry of the load width. Furthermore, since the load range is limited, operability is also poor.

[0022] Therefore, the induction heating mechanism is oscillated in the axial direction of the roller as necessary to generate the necessary amount of heat even in areas outside the load range, thereby canceling out the tendency of the temperature to decrease in the no-load area. This also allows the uniform temperature zone to follow meandering loads and changes in width. Furthermore, even when the jacket chamber and the induction heating mechanism are set to be shorter than the load width, it is possible to uniformly heat the areas facing the jacket chamber at both ends of the load on both sides.

[0023] As a result of the above, the difference between the surface temperature of the roller in the area with no heat load and the surface temperature of the roller in the area with heat load is reduced, the steep temperature gradient between the two is eliminated, and the heat load is reduced in the width direction. It will be heated evenly along the Further, since the surface temperature of the roller in the area with no heat load does not rise, no radial expansion occurs, and overpressure only at both ears is avoided.

[0024]

[Embodiment] An embodiment of the present invention will be explained with reference to the drawings. 1 is a roller, 2 is a drive shaft integrally attached to both sides thereof, and is rotatably supported by a machine base 4 via a bearing 3. Reference numeral 5 denotes a plurality of jacket chambers provided independently from each other inside the peripheral wall of the roller 1, and these are formed by drilling along the axial direction of the roller 1, for example, with a drill. Inside the jacket chamber 5, a gas-liquid two-phase heating medium such as distilled water is sealed.

Reference numeral 6 denotes an induction heating mechanism, which is supported by a support rod 7. The support rod 7 is inserted into the drive shaft 2 and supported by the drive shaft 2 via a bearing 8 . The induction heating mechanism 6 includes an induction coil 10 and an iron core 11. The induction coil 10 is connected to an AC power source via a lead wire 12. A thermal load 13 is transferred while being in contact with the surface of the roller 1.

The above configuration is not particularly different from a conventional induction heating roller device of this type. According to the invention,
The lengths of the jacket chamber 5 and the induction heating mechanism 6 (strictly speaking, induction coil) along the axial direction of the roller 1 are set to be equal to or shorter than the width of the thermal load 13.

The support rod 7 supporting the induction heating mechanism 6 is swingable from side to side inside the roller 1 along the axial direction of the roller 1. The swing mechanism 14
Although any one can be used, the illustrated example shows a configuration using an air cylinder 15.

A piston 16 within the air cylinder 15 is connected to the end of the support rod 7. By selectively supplying air to the chambers on both sides of the piston 16 and driving the piston 16 left and right, the support rod 7, and therefore the induction heating mechanism 6, can be swung left and right.

Specifically, the position of the induction heating mechanism 6 is detected by a position detection device (not shown), and the air cylinder 1 is detected by a signal fed back from the position detection device (not shown).
It is preferable to control the swinging range of the induction heat generating mechanism 6 by the induction heating mechanism 5.

The oscillation period is controlled in accordance with the temperature difference between the heat load area and the non-load area adjacent to the heat load area. To do this, it is sufficient to detect the temperature of the heat-loaded area and the non-loaded area on the surface of the roller using a thermometer, and control the oscillation period to such an extent that the temperature difference between the two areas does not exceed a certain value.

The heat generated by the roller 1 by the induction heat generating mechanism 6 and the uniform heat effect by the jacket sheet 5 are exerted on the surface portion of the roller 1 that faces them. This results in a heat load of 1
3 is heated uniformly over its entire width.

When the difference in temperature between the heat load area and the adjacent non-load area becomes large, the induction heating mechanism 6 is swung left and right via the support rod 7. This oscillation increases the temperature of the adjacent no-load area without substantially reducing the temperature of the heat-loaded area. This makes it possible to reduce the temperature difference between the two regions.

[0033]

Effects of the Invention As explained above, according to the present invention, it is possible to uniformly heat a roller equipped with a jacket chamber under heat load, and at the same time reduce the temperature difference between the heat load area and the non-load area. This has the effect of reducing the amount of water used.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention.

[Explanation of symbols]

1 Roller 5 Jacket room 6 Induction heating mechanism 7 Support rod 13 Heat load 14 Swing mechanism

Claims (1)

[Claims] [Claim 1] Extending in the axial direction on the peripheral wall of the roller,
Further, a jacket chamber in which a gas-liquid two-phase heating medium is sealed is provided, and an induction heating mechanism is provided inside the roller, and the jacket and the induction heating mechanism have a width equal to or equal to the width of the thermal load of the roller. An induction heating roller device that is set shorter than this, and in which the induction heating mechanism is swingable along the axial direction of the roller.