FI104910B - Heated roll and a method for controlling the temperature of a heated roll - Google Patents

Description

0 104910

Heated Roll and Method for Adjusting the Heated Roll Temperature Upphettbar Vals och förfarande för regiering - av temperatureuren hos en upphettbar Vals 5

The invention relates to a heated roll for a papermaking machine, a paper finishing device or the like, comprising rolls extending from one end of the roll to the other end of the roll, heated by means of a heating medium for heating the roll surface. comprises ends at each end of the roll.

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The invention also relates to a method for controlling the temperature of a roll to be heated, wherein the roll is heated by heating medium circulating through the first end to the second end of the roll, or the like.

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In paper machines and paper finishing equipment, particularly the press section and finishing calendars, generally heated rollers are used. The heating of the rolls is generally treated with a heat transfer medium such as hot water or oil. There are mainly two types of heated rolls 25. On the other hand, heating rolls are known in which the roll mantle or the massive roll is provided with substantially axial bores formed near the outer surface of the roll through which the heating medium is passed from end to end of the roll. There are generally a plurality of these bores spaced evenly along the circumference of the roll. The heating medium may have been made to rotate the roll in said bores either once. end to end, or two or more times, with the heating medium passing in opposite directions in adjacent bores. On the other hand, so-called heated rollers are commonly used. double diaper 35 patellas or rollers having an indentation piece, wherein an indentation piece is disposed on the inside of the roll casing so that an annular space is provided between said insertion piece and the inner surface of the roll casing to which the heating medium is adapted to rotate from roll to end.

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The present invention relates to heated rollers of the first type, i.e. rolls provided with substantially axial bores formed near the outer surface of the roll.

Although in known heating rolls the fluid circulation channels, i.e. the bores, are mostly drilled symmetrically, due to different stress triggering by heat and possible asymmetric flow of the fluid circulation, the temperatures are practically not ideal and thus not completely straight. This results in diameter variation and line pressure variation due to curvature, which can even act as an oscillator. It is an object of the invention to provide a solution to the problem discussed above.

Another problem with heated rolls is that when using heated rolls, e.g., nip rolls, against a soft roll, a paper gradient that is less than the width of the nip creates a strong temperature gradient in the peripheral areas, which may damage the soft roll coating. This high temperature region is due to the fact that heat from the surface of the thermal roller is not transferred to the paper, but it warms the periphery of the thermal roller from the area outside the paper web to very hot. The object of the invention is also to provide a solution to this problem.

In the prior art relating to the invention, reference is made to U.S. Patent No. 5,285,844, which discloses a heated or cooled roll, the roll casing of which has axially extending bores at the ends of the roll which are joined by a solid annular body 30 sealed to each other. or feed or outlet lines for heating media * · located outside the roll. In this arrangement, the bores are provided with an insulator for the peripheral areas of the roll, which is secured by an annular fastener or a directly rotatable screw-like adjusting element which passes through the end-35 of the roll and can be rotated from the outside. This adjusting element is provided with holes and is preferably hollow and a wedge is provided in connection with the bore, which is positioned to correspond to the wedge opening, whereby the insulating piece around the bore remains in place. This dielectric block is movable axially to control the thermal effects of the peripheral regions. An annular kappa-5, which is provided on the end of the roll and has channels, is provided with a heat transfer medium to the drill holes of the roll through the holes made in the adjusting element and the hollow adjusting element.

This known arrangement is quite complex and its adjustability is limited. The object of the invention is to provide a simpler solution with respect to this known arrangement, in which the temperature control of the peripheral areas can be achieved over a wider area, and at the same time the liquid circulation can also be controlled.

In order to achieve the foregoing and further objects, the method according to the invention is characterized in that at least a portion of the roll media heating passages are provided with bores at least at one end of the roll through which the adjusting screws extending into the media media passages or

The roll of the invention, in turn, is essentially characterized in that the circulation of the heating medium is controlled at the end of the duct through a bore through the end of the roll by means of an adjusting screw extending into the duct.

According to the invention, holes passing through the first end to the second end of the roll are drilled into one or both ends / ends of the roll, through which adjusting screws are inserted at the channels 30, whereby flow in the duct can be throttled and thus circulation / heat transfer . in the flow duct, define the required screw adjustment. If there are multiple channels in the same flow circuit, then the minimum is one adjustment screw per flow circuit. In addition, the adjusting screw body is clamped at the end by a thread 35 or a similar removable solution, whereby the insulating / metal bushings located at the edge of the drill roll at the adjusting screw can be removed and the insulating width can be changed e.g. To prevent leaks, for example, tapered screw plugs and sealing plugs or similar arrangements are provided at the end of the roll, which are easy to open / close but seal the end of the roll. The adjusting screws are identified and provided with a measuring scale for performing adjustment and correcting the measuring position.

The arrangement according to the invention achieves e.g. the following benefits.

The surface temperature of the heating sectors, i.e. the roll straightness, is adjustable via an adjusting screw by controlling the flow of the heating medium in the bore. The insulating / metal sleeve series of the hole for the adjusting screw is interchangeable to adjust the heating width to the track width. Thus, two different types of control characteristics are achieved by the same construction.

The arrangement according to the invention is inexpensive and easy to manufacture and is also applicable to rolls already in use, for example, by modernizing the ends of the rolls or by making new ones into the old rolls.

Adjustments can be made while the roller is hot in the machine, allowing measurements to be made to adjust the throttling process to * 25 equilibrium conditions. The quality of the paper to be produced is improved as the line pressure in the nip is stabilized, vibrations are reduced, and grinding intervals are increased as coating damage is reduced.

In the following, the invention will be described in more detail with reference to the figures in the accompanying drawings, in which details the invention is not intended to be narrowly limited.

Fig. 1 shows schematically a drilling of a heated roll having an arrangement for controlling the flow of the heating medium 35 according to the invention.

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Fig. 2 is a diagrammatic view of a heated roll having a drilling width adjustment arrangement in accordance with the invention in addition to the adjustment arrangement shown in Fig. 1.

Figures 1 and 2 schematically illustrate exemplary embodiments of the invention in connection with a single drill having a bore 13 for the adjusting screw 20 at the end 12 of the roll 10. In the body 10 of the roll 10, the flow passage near the surface 17 of the roll 10 is denoted by the reference numeral 14. The adjusting screw 20 is positioned such that its conical tip 31 strangles the back of the vir-10 in the desired channel 14. The adjusting screw 20 in the hole 13. The hole 13 is sealed with a closure 21 which is removable and, if necessary, can be provided with a sealing compound. By changing the position of the adjusting screw 20 in the bore 14, the throttle can be changed, whereby the heat circulation in the roll 15 can be adjusted. Around the bore 14 is provided a sleeve set 25,26,27 at the periphery of the roll, which are dielectric sleeves or metal sleeves depending on the width of the paper web to be produced, using metal sleeves in the paper web area and dielectric sleeves outside the web areas can be blocked. The sleeve set 25,26,27 is replaced by first unscrewing the adjusting screw 20, whereby the sleeve 25,26,27 is replaceable through the hole 13 in the end 12 of the roll 10.

The invention has been described above only with reference to a preferred embodiment thereof, the details of which, however, are not to be construed as being limited in any way. Many modifications and variations are possible within the scope of the inventive idea defined in the following claims.

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Claims (9)

A heatable roll for a paper machine, a paper finishing device or the like, which roll (10) comprises adjacent the surface 5 (17) of the roll (10) extending from one end of the roll to the other end channels (14) heated by means of a heating medium for heating the surface (17) of the roller (10), the heating medium being set to circulate through these channels (14), the roller (10) further comprising gables (12) in each end of the roller 10 (10), characterized in that bores (13) are made in at least one end (12) of the roller (10) at least at a portion of heating medium channels (14) in the roller (10), through the bores (13) are arranged in the heating medium channels (14) extending control screws (20) or equivalent for controlling the flow of the heating medium in the channel (14). 2. A roller according to claim 1, characterized in that a control screw is provided in the channel for a main flow in the roller (10) when the same flow circuit has several channels. 20 Roll according to claim 1 or 2, characterized in that a sleeve series (25, 26, 27) is placed in the edge regions of the roll in the heating medium channel (14) through the bore (13) made in the end (12) of the roll (10). , which series comprises insulator and / or metal sleeves in such a way that the heating width of the roller can be selected to correspond to the conditions and that the metal sleeves are located in the web area and the insulator sleeves outside the web range. Roll according to claim 3, characterized in that the sleeve series (25, 26, 27) can be replaced by the bore (13) made in the end (12) of the roll (10). Roll according to any of claims 1-4, characterized in that the control screw (20) is fixed with its body with threads (22) at the end (12) of the roll (10). • ·,. Roll according to any of claims 1-5, characterized in that means (21) for sealing the bore (13) in the roll end are located in the bores (13) outside the control screw (20) in the end (12) 40 of the roll (10). ). Roll according to any of the preceding claims, characterized in that the control screws (20) are provided with a measuring scale or equivalent for observing the control quantity. 9 104910 A method of controlling the heating temperature of a heated roller, wherein the method of the roller (10) is heated by mediating a heating medium which circulates through channels (14) recorded in the roller (10) or the like extending from one end of the roller 5. to the other end, characterized in that the circulation of the heating medium is controlled by the mediation of a control screw extending into the channel through an end (12) of the roller (10) made by a gable (12). drilling (13). 10 9. A method according to claim 8, characterized in that the heating of the edge region of the roller in the process is controlled by an insulator / metal sleeve series in such a way that metal sleeves are placed in an area to be heated and insulating sleeves in an area to be insulated in the heating medium channel. in the gable of the roll made in the heel, wherein the surface temperature of the edge areas can be affected by changing the order of the sleeves. > 0 • · • ·