FI124676B - Arrangement for heating the headbox of a fiber web machine - Google Patents

Description

Arrangement for Warming the Fiber Machine Machine Headbox

The invention relates to an arrangement for heating a headbox of a fiber web machine adapted to form a pressurized heating circuit 5 comprising a fluid circulation for heating medium, of which the headbox structures form a part thereof,

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Fiber web machines are known for temperature-control of headbox structures. The reasons for the need for regulation and some arrangements for its implementation are disclosed in Finnish Announcements Nos. 67592 and 80488.

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The solutions known in the art are dimensioned in such a way that their operation is economically disadvantageous. The heating power of the system may have been several tens of kilowatts, some up to 50 kW. In addition, the solution components 20 are often located quite far from the headbox itself, so that the fluid circulation parts have to be insulated due to long piping, for example to minimize heat loss. As the components are located away from the headbox, the height differences can also become large, which also results in its own losses and requirements for, for example, pump dimensioning.

It is an object of the present invention to provide an arrangement for heating the headbox of a fiber web machine which is more energy efficient and more compact than the known arrangements. The features of the arrangement according to the invention are set forth in claim 1.

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I - J The objects of the invention are achieved by pressurizing the heating circuit.

According to one embodiment, the subcomponents of the arrangement can be placed very close to the headbox itself, even up to the headbox frame structures. In this way, the piping required by the arrangement is shortened and heat losses can thus be minimized. With pressure, the importance of altitude fluctuations also disappears. Thus, for example, the heating means can also be positioned more freely with respect to the known one. Other additional advantages achieved by the invention will be apparent from the description and features of the appended claims.

The invention, which is not limited to the following embodiments, will be further described with reference to the accompanying drawings, in which:

Figure 1 is a schematic diagram of a headbox heating circuit and

Figure 2 is a side view of the headbox.

Figure 1 is a rough diagram illustrating an arrangement for heating the headbox 14 of a fiber web machine. The fibrous web machine can be, for example, a paper or board machine, a pulp machine or a distillate machine. The headbox 14 is applied and fed in a manner known per se to the web forming section 20 of the fiber web machine following the headbox 14, which in the case of Fig. 1 would be on the right side of the headbox 14. As such, the function, structure and function of the headbox 14 will be apparent to one skilled in the art and will not affect the basic idea of the invention.

The arrangement provides a heating circuit 10 comprising a fluid circulation ^ 12.1-12.6, 21, 22 for the heating medium and means 13 arranged in the fluid circulation ^ for heating the heating medium.

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A part of the fluid circulation is formed by the structures of the headbox 14, in particular the lower and upper body 21, 22 (Fig. 2). In the invention, the heating x £ 30 circuit 10 is closed and pressurized. As an example, pressures from the level may be mentioned in the range of 0.5 to 3 bar. Correspondingly, the temperature of the heating medium, of which water represents an example, may be, for example, 40 to 70 °, typically a few degrees above the temperature of the processes.

35 The heating means 13 include an insulated accumulator 16 provided with resistive means 15. The volume of the reservoir 16 may be adapted to the size of the headbox 14. Further, the arrangement 5 also includes expansion means 17 for compensating for pressure variations in the heating circuit 10. According to one embodiment, the expansion means 17 may include a diaphragm expansion vessel 18. In another embodiment, the pressure variation compensation of .

The arrangement also includes pumping means 19 for circulating the heating medium 10 in the heating circuit 10 and means 20 for venting the heating circuit 10. The pumping means 19 ensure an efficient circulation of the medium 15 and the venting means 20 uniformly distribute the heating power to the entire circuit 10.

Figure 2 shows an example of a headbox 14 seen from the treatment side of HP. The structures of the headbox 14 are shown in dashed lines 20. Here, the arrangement is fitted to the headbox 14 known by the Applicant's ValFlo trade name. It should be understood, however, that the arrangement according to the invention can be fitted in principle to any headbox without major modifications. Figure 2 also shows one way of implementing the heating circuit 10 for the headbox 14 structures in which the heating medium is f-adapted to circulate and act. Heating circuit 10 starts to C \ 1, tending side HP with respect to the opposite end of the drive side

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at the end where the hot water heater 16 is located.

at least some of the lines 13 are integrated into the structure xa. 30 of the headbox 14, in this case the lower body 21. In addition to the reservoir 16, the expansion vessel 18 is now also in the rib space 23 of the lower body 21.

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o Pipeline 12.1 (Figure 1) leaving accumulator 16 is connected

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the rear cross beam 21 of the lower part of the channel 11.1 of the lower frame 35 along which a medium is introduced into the service side HP end. This channel may also have a valve (not shown) for the addition line, with a presetting pressure of 1 bar. In connection with the rear lower beam duct 11.1, a circulating pump 19 with upstream and downstream pipelines 12.2 is provided. At pump 19, bar 11.1 is cut off.

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Half HP Care from the pipeline is 12.3 from the rear bottom bar of the front-kikanavasta 11.1 11.2 alapalkkikanavaan. Also, the expansion tank 18 is placed in the HP-side end of the lower frame 21 within the space 23. The expansion tank 18 is connected to a safety valve 10 a pipe fitting 24 equipped with a 25 channel 11.2.

The expansion pressure of the expansion vessel 18 may be, for example, 0.5 bar.

The drive side from the circuit 10 continues from the front lower beam alahuulikanavaan channel 21 at the top of the lower frame 11.2 11.3 15 wherein the medium is again introduced into the service side HP end. Lower lip channel 11.3 circuit 10 continues the pipeline along the upper frame 22 12.5 11.4 ylähuulikanavaan and then again drive-side end face. Pipeline 12.6 leads from the lower lip channel 11.3 to the upper beam 26 of the upper body 22, which in this case is a coaxial structure.

20 Top bar 26 of the outer shell and the inner space between the channel 11.6 11.5 liquid is introduced from the service side HP, where it is passed along the inner channel 11.6 drive-side end and the return line 12.7 to the back of the lower frame 21 within the tank 16.

The invention provides a simple pipe loop. Closed <- circuit 10 ensures that no air enters the circuit and, with its C \ 1, even stainless steel grades which do not require corrosion can be used in the lining pipes 12.1 to 12.7. The h-arrangement according to the invention can be implemented with standard components. Above

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The single circuit solution shown in £ 30 may equally be dual circuit, where, for example, the lower and upper bodies 21, 22 have their own independent liquid circuits. Although, in the above embodiment, the accumulator 16 and the expansion vessel 18 are disposed within the lower body.

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21, they may also be separate from the headbox 14 35 as an example of a kit for headformers.

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It is to be understood that the foregoing description and the accompanying drawings are intended only to illustrate the present invention. Thus, the invention is not limited to the embodiments set forth above or as defined in the claims, but many variations and modifications of the invention which are possible within the scope of the inventive concept defined in the appended claims will be apparent to those skilled in the art.

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Claims (7)

An arrangement for heating the inlet carriage of a fiber web machine, which is arranged to form a heating circuit 5 (10) under pressure, which comprises - liquid circulation (11.1 - 11.6, 12.1-12.7) for the heating medium in which the constructions (11.1 - 11) - 11.6) forms part of the heating means (13) arranged in the liquid orbit (11.1 - 11.6, 12.1 - 12.7) for heating the heating medium, characterized in that at least part of the heating medium (13) is integrated in the inlet drawer (14). ) constructions (21). Arrangement according to claim 1, characterized in that the heating media (13) comprises an insulated accumulator (16) equipped with resistance devices (15). Arrangement according to claim 1 or 2, characterized in that the arrangement comprises expansion means (17) for compensating pressure changes in the heating circuit (10). Arrangement according to claim 3, characterized in that the expansion devices (17) comprise at least one membrane expansion tank (18). • t δ c \ j Arrangement according to any of claims 1-4, characterized in that the arrangement comprises pumping devices (19) for circulating the heating medium in the heating circuit (10). £ 30 Arrangement according to any of claims 1-5, characterized in that the arrangement comprises means (20) for venting the heating circuit (10). CM Arrangement according to any of claims 1-6, characterized in that the pressure of the heating circuit (10) is 0.5 - 3 bar.