JPS63256791A - Apparatus and method for heating calender roll - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heating device for heating a calender roll and a method for heating a calender roll. In particular, the present invention relates to a heating device that heats a calender roll using induction heat and heat supplied from a heat transfer medium.

[Conventional technology]

Various calenders have been used in the past to smooth the surface of dry webs to increase the printability of paper and paperboard produced by paper machines.

Basically, a calender has at least a pair of cooperating rolls that form a calender nip between the rolls, thereby smoothing and finishing the surface of the dry web. Depending on the type of surface required, the calender rolls are made of polished metal or consist of a combination of one polished metal roll and a soft support roll. Soft rolls include elastomer-covered rolls and so-called filled rolls with a plurality of compressed cotton discs.

When an abrasive metal roll is utilized in combination with a soft roll, the practical application is to heat the surface of the metal roll such that heat is transferred from the surface of the roll to the surface of the web extending between the metal roll and the soft roll. It has been found that this improves the gloss transferred to the paper surface.

Many proposals have been made in the past, but among them,
A heating medium, such as oil, was allowed to flow through a plurality of channels or ducts extending through the rolls. Heat from the oil is transferred to the roll and the heat is transferred to the surface of the roll to heat the web passing therethrough.

[Problem to be solved by the invention]

In an application example consisting of the above-mentioned conventional technology, the surface of the roll is
Heated to over 49°C (300°F), sometimes 510”C
Heating to as high as (950'F) is desirable. However, in order to heat the surfaces of such calender rolls to these high temperatures, a heat transfer medium such as oil must be supplied at a temperature that significantly exceeds these required surface temperatures. This results in significant temperature drops in the various hot fields and shells.

Two main problems arise from utilizing heat transfer media operating at such high temperatures. Firstly, the shell of the calender roll is overstressed and secondly, it is very dangerous to handle heat transfer media such as oil at such high temperatures.

U.S. Pat. No. 3,489,344, granted to Mr. Keyes and assigned to Beloit, Corporation, demonstrated the problem of controlling the thermal profile of a roll along the cross-machine direction, but did not overcome the aforementioned problems. It does not indicate how to do so.

The present invention therefore proposes a calender roll which combines an induction heater which induces heat in the region of the outer surface of the calender roll and heat which is transferred to the calender roll by means of a heat transfer medium flowing through channels passing through the calender roll. Provides a new heating device for heating.

A suitable device of the present invention overcomes the aforementioned problems associated with conventional calender roll heating devices and thus makes a significant contribution to the technology of the Gi calender and the like.

Another object of the invention is to provide a heating device for heating a calender roll in which a heat transfer medium is passed through a heating channel formed by the roll so that heat is transferred from the heat transfer medium to the roll. That's true. Induction heaters induce heat in the area of the outer surface of the roll to supplement the amount of heat transferred from the heating medium.

Another object of the present invention is that the temperature of the outer surface of the roll is
If an induction heating device is not provided, it is an object of the present invention to provide a heating device for heating the calender roll by induction heating to a level sufficient to cause stress in the shell.

Another object of the invention is to provide a calender roll such that the outer surface of the calender roll can be heated to a temperature level without creating the risks associated with using heat transfer media operating at such high temperature levels. An object of the present invention is to provide a heating device for heating.

Another object of the invention is that the heating medium is
The heating medium is supplied to the roll at a temperature in the range of 400-600°F (4-316°C), thereby avoiding the dangers associated with using such heating media above the aforementioned temperatures. An object of the present invention is to provide a heating device for heating a calender roll.

Yet another object of the invention is that the heat transferred by the heat transfer medium to the calender rolls is controlled by:
That is, heating a calender roll in such a way that induction heat in a region around the outer surface of the roll is retained within that region by preventing induction heat from flowing inward through the roll from the region around the outer surface. An object of the present invention is to provide a heating device.

Another object of the invention is to heat the calender roll in such a way that the heat transferred from the heat transfer medium to the calender roll prevents induced heat from dissipating inwardly through the roll from the outer surface of the roll. The purpose is to provide a method.

[Means and operations for solving the problems] The present invention relates to a heating device and a heating method for heating a calender roll using heat supplied from a heat transfer medium by induction.

This heating device has heating channels formed by calender rolls. These channels extend through the rolls so that the heat transfer medium flows through the channels and heat is transferred from the transfer medium to the rolls. The induction heater is located adjacent to the outside of the calender roll and extends over virtually the entire length of the roll, so that when the induction heater is energized, heat is generated in the area of the outside surface of the roll. Rather than a single heater, multiple heaters can also extend along the entire length of the roll. This induction heat replenishes the amount of heat transferred from the heating medium, so that the temperature on the outside surface of the roll increases to a level that would otherwise stress the shell if the induction heater were not used. Furthermore, such temperature levels can be achieved without the risks associated with using heat transfer media that operate at such high temperature levels.

In particular, the heating channels extend longitudinally through the calender roll so that the heating medium flows over the entire length of the roll, thereby transferring heat from the heating medium to the roll. Heat from the heating medium moves through the roll towards its outer surface by conduction.

In a first embodiment of the invention, the heating medium is oil, and in another embodiment superheated water.

Heating medium: 204-316°C (400-600°F)
Since the rolls are fed at a temperature within this range, the dangers associated with using heating media above this temperature range can be avoided.

The heating medium is 121 to 177'C higher than the temperature of the roll surface.
(250-350″F) supplied at temperatures within the high range.

Induction heaters generate heat in the area of the outer surface of the roll. The heat transferred to the roll by the heat transfer medium is retained in the aforementioned areas by preventing the heat generated by the induction heater from flowing inwardly through the roll from such areas.

The present invention provides a method of heating a calender roll using heat provided by an induction heater and a heat transfer medium. The method includes passing the heat transfer medium through a heating channel formed by the roll to transfer heat from the heat transfer medium to the roll such that the roll is heated; energizing an induction heater located adjacent to the roll, the induction heater extending along the length of the roll such that heat is generated in the region of the outer surface of the roll.

Furthermore, heat transfer from the heat transfer medium to the roll prevents induced heat from dissipating inwardly through the roll from the outer surface of the roll.

〔Example〕

One embodiment of the present invention will be explained with reference to FIGS. 1 to 4. FIG.

Figure 1 shows a heating device y1 that heats the calender roll 02).
．． It is a side view of 0ω. This heating device θ0) utilizes heat supplied from a heat transfer medium by an induction heater device. FIG. 1 shows a web W extending through a calender nip 00 formed by a calender roll Oz and a cooperating soft calender roll surface.

This induction heating device 04) has a ferromagnetic core (a), the concave surface (22) of which is arranged so as to be adjacent to and partially extend around the outer surface (24) of the calender roll 0''IJ. .A wire coil (2
8) expands, and both ends (30) of its coil (28) (
32) is connected to the alternating current source (34), so that when its coil (28) is energized by the alternating current source (34), heat is generated in the part of the calender roll (+21) adjacent to the outer surface (24). Occur.

Electromagnetic eddy currents are generated in the ferromagnetic core by one of the following two methods. When the alternating current source (34) connects to the copper wire coil (28), the ferromagnetic core C! A copper wire coil (28) can be wound around its ferromagnetic core 12I so that vortices are generated in I). Also, when the AC source (34) is connected to the copper pipe, it is possible to run the liquid-cooled steel pipe in a straight line only for the length of the ferromagnetic core such that a vortex is generated in the ferromagnetic core (to). . Whichever method is used to generate vortices in the ferromagnetic core, vortices are induced in the region of the outer surface (24) of the calender roll in the vicinity of the ferromagnetic core t2I.

This area of the outer surface (24) of the calender roll will be heated by the induced swirl.

FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. 1, showing the induction heater device (b) arranged along substantially the entire length of the calender roll 021. The calender roll 021 is formed with a plurality of elongated channels extending along the entire length of the roll (12+). Each channel (36-50) is connected to the calender roll α2 as shown in FIG. A central channel (54) extending through the support shaft (56) is provided with radial branch holes (
52) Connect by (53). The heat transfer medium, e.g. oil or superheated water, is connected to a plurality of heating channels (36
) to (50) so that the heat transfer medium circulates throughout the length of the calender rolls.

FIG. 3 is a cross-sectional view taken along 3-3#lA in FIG. 2, and shows a plurality of longitudinally extending channels (36) to
(50), these channels are arranged radially inwardly with respect to the outer surface (24) of the calender roll 02), each longitudinal channel (36)-(50) being arranged radially inwardly with respect to the outer surface (24)
) located at equal intervals from When a heat transfer medium, such as heating oil, circulates through these channels, heat is transferred from this heat transfer medium to the calender rolls, and this heat supplied by the heat transfer medium is transferred by the induction heater device A. The supplied heat is applied to the outer surface (24) and the adjacent
Prevents inward dissipation from the J region. By this means, the heat supplied to the calender roll 021 by the heat transfer medium is supplemented by the heat induced by the induction heater device side, which when not in use is applied to the area of the calender roll Oz, i.e. to the shell. This can prevent stress that would otherwise occur. Furthermore, by supplementing the heat supplied by the heat transfer medium together with the heat from the induction heater side, the oil, i.e. the heating medium
There is no need to heat oil above 6000F (316°C), thus avoiding the dangers associated with pumping oil and the like at temperatures above 316°C (6000F).

Figure 4 shows the calender roll 0, which is a super calender roll, and the support roll, ie, the soft calender roll 0.
8) and these cooperative roles o2).

08) is a perspective view showing a web of paperboard or paperboard extending through a calender nip 0θ formed by 08).

When operating the heating bag 7f00), the heat transfer medium moves through the heating channels (3G) to (3G) formed by the calender roll surface.
50) and from the heating medium to the calender roll 0
The heat moves to 21 and heats the roll Q2+. The induction heater device side is energized so that the outer surface (24) of the roll (+21) is heated. Such an induction heater not only heats the outer surface (24) of the calendar roll 07J, but also heats the outer surface (24) of the roll 021. 24) Also heats nearby areas.The heat transfer from the heat transfer medium to the roll OZ prevents the induced heat from dissipating inwardly from the outer surface (24) of the roll 0 through the roll 02). can.

Although the present invention has been specifically described with respect to a calender for calendering a paper web, the present invention is not limited to calenders for paper webs, but rather heats the calender rolls used in calendering web-like materials. It should be understood by those skilled in the art that this includes heating devices and methods for heating. Furthermore, although the invention relates to a calender, the invention also encompasses arrangements in which one or more of the calender rolls are replaced by an elongated nip provided by a shoe and a cooperating plank. It should be understood that

Furthermore, the present invention is not limited to the specific embodiments described herein, but may include various modifications within the spirit and scope of the invention as limited by the claims. , should be understood by those skilled in the art.

〔Effect of the invention〕

As explained above, the calender roll heating device and heating method of the present invention can have the following effects.

(1) By raising the temperature of the outside surface of the roll using heat generated by an induction heating device placed near the outside of the calender roll, the temperature of the heat transfer medium such as oil supplied to the roll is lowered, and the high-temperature heat f8 Various dangers that arise when using media can be avoided.

(2) Since the temperature of the outer surface of the roll is set to a predetermined temperature by the heat from the heat transfer medium and the heat generated by the induction heating device, only the heat of the heat transfer medium is used without providing an induction heating device. The stress generated in the roll shell can be suppressed compared to the case of the roll shell.

(3) The heat transferred to the calender rolls by the heat transfer medium prevents heat from the induction heating device from flowing inward through the rolls.

As described above, the present invention can provide a simple device and method that can prevent problems such as shell stress by supplying supplementary heat to the surface area of the super calender roll. The invention can solve the problems that arise when dealing with internal heat transfer media at high temperatures.

[Brief explanation of the drawing]

FIG. 1 is a side view of a heating device as an embodiment of the present invention, showing a calender roll and an induction heater adjacent thereto; FIG. 2 is taken along line 2-2 in FIG. 3 is a sectional view taken along line 3--3 in FIG. 2, and FIG. 4 is a perspective view of the apparatus shown in FIGS. 1-3. (Symbols in the figure) 00--Heating device flush Calendar roll 041--Induction heater device 0ω...-Calendar nip side--Soft calender roll QI---
Ferromagnetic core (22) - m - Concave surface of the core (24) -- Outer surface of the calender roll (28) --
Wire coil (34)--AC llt source (36-
50) - Channel (52) (53) - Branch hole in one radial direction Patent attorney Akira Sakama 3 people Fl (3,2

Claims (1)

Claims: 1. Formed by calender rolls and extending through said calender rolls through which a heat transfer medium flows such that heat is transferred from the heat transfer medium to the calender rolls. a heating channel disposed near the outer surface of the calender roll and extending over substantially the entire length of the calender roll and extending through the outer surface of the roll for replenishing the amount of heat transferred from the heat transfer medium upon energization; heat is generated in the area to raise the temperature of the outer surface of said roll to a temperature level that would otherwise cause excessive stress in the shell without the induction heating device, and the heat transfer medium is heated to at least such a temperature. an induction heating device capable of reaching said temperature level without creating the dangers that would arise if used in a calender using heat supplied from said induction heating device and a heat transfer medium A heating device that heats the roll. 2. The heating channel extends longitudinally through the calender roll so that a heat transfer medium flows over the length of the roll to transfer heat therefrom to the calender roll, and heat from the heat transfer medium is conducted. 2. Heating device according to claim 1, characterized in that the heating is transmitted through the calender roll towards its outer surface. 3. The heating device according to claim 1, wherein the heat transfer medium is oil. 4. The heating device according to claim 1, wherein the heat transfer medium is superheated water. 5. The heat transfer medium has a temperature of 204~316℃ (400~60℃)
2. Heating device according to claim 1, characterized in that it is supplied to the rolls at a temperature in the range of 0 DEG F., thereby avoiding the dangers that would arise if a heating medium was used above the temperature range. 6. The induction heating device is an induction heater that extends along the outer surface of the roll and generates heat in the area, and the heat transferred to the roll by the heat transfer medium is caused by the induction heat from the area. 2. The heating device of claim 1, wherein heat within the region is retained within the region by preventing it from flowing inwardly through the rolls. 7. The heat transfer medium has a temperature of 121° to 177°C (250° to
2. The heating device of claim 1, wherein the heating device is supplied to the roll at a temperature within a range of 350 DEG F. above the roll temperature. 8. a heating channel extending through the roll formed by a calender roll, through which a heat transfer medium flows, and heat is transferred from the heat transfer medium towards the outer surface of the roll; ; located adjacent to the outer surface of said roll and extending along substantially the entire length of said roll to provide heat to an area of the outer surface of said roll for replenishing the amount of heat transferred from the heat transfer medium when energized; generated that would raise the temperature of the external surface of the roll to a level that would cause excessive stress in the shell in the absence of the present induction heater, at least when using a heat transfer medium at such temperature level. A heating device for heating a calender roll using heat from induction heating and heat supplied from a heat transfer medium, characterized in that it consists of: an induction heater capable of obtaining said temperature level without creating danger; . 9. Passing a heat transfer medium through a heating channel formed by the roll to transfer heat from the heat transfer medium to the roll to heat the roll, and disposed adjacent the outer surface of the roll; energizes an induction heater extending along the entire length of the roll to generate heat in the area of the outer surface of the roll, and heat transferred from the heat transfer medium to the roll causes the heat generated by the induction heater to be transferred to the outer surface of the roll. a method of heating a calender roll using heat provided by an induction heater and a heat transfer medium.