JPH0368156B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is a porous wet web, for example, a method for removing liquid components such as water impregnated into a thin fibrous web such as thin printing paper during the manufacturing process of the web. The present invention relates to a device for removing liquid from a web.

[Prior Art] FIG. 8 is a schematic diagram showing a part of a conventional paper making line. The web 1 formed through the head box and wet part is dehydrated in a press part 2 and a drying part 3, and then finished in a calender part 4 to become a product. In the drying part 3, the web 1 is brought into contact with a cylindrical dryer cell 5 heated by blowing steam,
The web temperature is gradually increased to evaporate and remove moisture. The web moisture content at the entrance of the drying part 3 is 50% to 60%, and the web moisture content at the exit of the drying part 3 for turning the web 1 into products is 7%. Therefore, the number of dryer cells 5 required to reduce the moisture content of the web 1 from 50% to 60% to 7% varies depending on the speed and thickness of the web 1, but is generally 50 to 70. , line length 3L of drying part 3 is also 50
~70m is required.

As a technology that is considered useful for shortening the line length in the conventional drying part 3, there is a water removal device according to USP 4,324,613. This moisture removal device allows a web conveyed in felt to pass through a nip area between a pair of heating rollers and an air permeable roller. The heated rollers of the moisture removal device deliver heat under high contact pressure to the web as it passes through the nip area, causing the moisture in the web to rapidly convert to the vapor that penetrates the web and remains in the web. This results in the free water being carried out to the felt side. Therefore, it seems that this moisture removal device has good moisture removal efficiency and can shorten the line length of the drying part 3 described above.

[Problem to be solved by the invention] However, according to the inventor's considerations, the above
In the moisture removal device of USP 4,324,613, the heating roller and the permeable roller form only one monotonous nip area, and the moisture removal state around the heating roller cannot be adjusted in various ways.

According to experiments conducted by the present inventor, if the moisture generated at the boundary with the heating roller evaporates too quickly, the generated steam may damage the web.
Therefore, it has been found that it is important to adjust the moisture removal state in the nip area formed around the heating roller.

An object of the present invention is to variously adjust the liquid removal state around the heating roller and improve the liquid removal performance.

[Means for Solving the Problems] The present invention according to claim 1 includes a transfer belt that includes a porous support surface and supports and transfers the web on the support surface, and a web supported on the transfer belt. A heating roller that rotates in thermal contact with the web, and a pressure welding device that presses against the back side of the carrying surface of the transfer belt that supports the web and forms a nip area between the heating roller and the transfer belt and the web. The heating roller delivers heat under high contact pressure to the web passing through the nip area, rapidly converting the liquid in the web to vapor, which penetrates the web and causes the vapor to flow through the web. In a web liquid removal device configured to transfer free liquid remaining on the web to a porous support surface side of a transfer belt, each of a plurality of pressing devices is installed at each position along the outer periphery of the heating roller. In addition, a nip position adjustment device is provided that can adjust the spacing between the nip regions formed by each pressure welding device, and the nip pressure generated by each pressure welding device in the corresponding nip region is adjusted independently for each pressure welding device. The device is equipped with a nip pressure adjustment device that can adjust the nip pressure.

The present invention according to claim 2 is the invention according to claim 1, further comprising: preheating the entire web from both the front and back sides of the web on the upstream side of the web line with respect to the nip area formed by the heating roller and the pressing device. A web preheating device is installed.

[Function] According to the present invention as set forth in claim 1, the following:
It has the function and effect of

A plurality of nip regions formed by a plurality of pressing devices and a quasi-nip region formed by a transfer belt are provided around the heating roller. The nip pressure in each nip region by each pressure welding device is independently set for each pressure welding device by a nip pressure adjusting device, and the nip pressure in the quasi-nip region caused by the transfer belt is determined by the belt tension. Therefore, the nip pressure state of each of the plurality of nip regions formed around the heating roller and the nip pressure state of the quasi-nip region can be adjusted independently.

The distance between the nip regions formed by each pressure welding device can be adjusted by the nip position adjusting device. Therefore, the timing of the liquid removal action exerted on the web by each of the plurality of nip regions formed around the heating roller and the length (time) of the quasi-nip region can be adjusted.

With the above, the nip pressure state of each nip area and quasi-nip area around the heating roller can be adjusted independently, and the position of each nip area and the length of the quasi-nip area can be adjusted, and as a result, the heating roller The liquid removal performance can be improved by adjusting the liquid removal status around the device in various ways.

According to the present invention as set forth in claim 2, there are the following effects.

The web, which has been entirely preheated including the front and back sides in the web preheating device, is introduced into the nip area between the heating roller and each pressure contact device. Therefore, the preheating device can preheat the liquid in the web until just before evaporation, and the thermal energy of the heating roller can be used more effectively for rapid and explosive vapor conversion. The device can raise the temperature of the liquid in the web to lower its viscosity (resistance to liquid removal).
The liquid discharge resistance due to the vapor generated by the heating roller can be reduced in advance. That is, this effectively complements the liquid removal effect according to the present invention as set forth in claim 1 above.

[Example] Fig. 1 is a schematic diagram showing a moisture removing device according to an embodiment of the present invention, Fig. 2 is a schematic diagram showing an enlarged main part of the moisture removing device, and Fig. 3 is a heating roller. A schematic diagram, FIG. 4 is a schematic diagram showing an example of applying the present invention to a paper making line, FIG. 5 is a schematic diagram showing another example of applying the present invention to a paper making line, and FIG. 6 is a schematic diagram showing an example of applying the present invention to a paper making line. It is a line diagram showing an effect.

As shown in FIG. 1, the moisture removal device 10 includes a transfer belt 11, a heating roller 12, and a pressure roller 13.
(pressure contact device), and the transfer roller 14
The water content of the web 1 guided and conveyed is removed.

The transfer belt 11 is made of a perforated steel belt, a glass fiber belt, a carbon fiber belt, etc., and has a porous support surface 11A, and supports and transfers the web 1 on this support surface 11A. (See Figure 2). The transfer belt 11 is wound around a support roller 16 provided on a machine base 15 in a circumferential manner. The transfer belt 11 has the function of absorbing moisture in the web, smoothing the web surface,
Equipped with the ability to withstand tension.

The heating roller 12 rotates in thermal contact with the web 1 supported by the transfer belt 11. here,
The heating roller 12 of this embodiment is constructed as shown in FIG. 3, with a roller main body 18 supported by a bearing 17 provided on a machine base 15, and the roller main body 18 is rotatable by a drive motor (not shown). The roller body 18 has a fixed shaft 2 therein via a bearing 19.
0 in a stationary state, and has a built-in magnetic flux generating section 23 constituted by an iron core 21 formed by a part of a fixed shaft 20 and an induction coil 22 wound around the iron core 21. The magnetic flux generating section 23 generates magnetic flux for inductively heating the roller body 18. The heating roller 12 also has an airtight chamber 18A within the thickness of the peripheral wall of the roller body 18, in which a heat medium (water, oil, etc.) is sealed in a vacuum state.

The pressure roller 13 presses the web 1 of the transfer belt 11.
A nip region N1 is formed in pressure contact with the back surface of the supporting surface 11A that supports the transfer belt 11 and the web 1, and presses the transfer belt 11 and the web 1 between it and the heating roller 12. Here, in the moisture removal device 10 of this embodiment, a pair of support stands 24 are provided on both sides of the lower part of the heating roller 12 on the machine stand 15, and each pressure roller 13 is rotatable on a bearing 25 provided on each support stand 24. By supporting the heating roller 12, the two pressure rollers 13 are respectively arranged at two positions along the outer periphery of the heating roller 12. Each pressure roller 13 also has an adjustment screw 26 that can adjust the position of the bearing 25 with respect to the support base 24.
(nip position adjustment device)
As a result, the distance between the nip regions N1 formed by the pressure rollers 13 can be adjusted. Note that the support stand 24 of each pressure roller 13
A pressure adjustment cylinder 27 (nip pressure adjustment device) is interposed between the press roller 13 and the machine base 15.
The nip pressure between the roller and the heating roller 12 can be adjusted as appropriate.

Furthermore, in the moisture removal device 10, a web preheating device 28 is provided on the upstream side of the web line with respect to the nip region N1 formed by the heating roller 12 and the pressure roller 13, for preheating the entire web 1 from both the front and back surfaces of the web 1. It is placed. Web preheating device 2
8 consists of a microwave, far/near infrared heater, etc. As shown in FIG. 1, the upper and lower heaters 29
It is constructed by supporting A and 29B on the machine stand 15 in an openable and closable state. 30 is a heater opening/closing cylinder.

Therefore, the moisture removing device 10 is installed in the fourth drying part 3 of the paper making line, for example.
As shown in the figure, it is used by installing one set of heating rollers 12 and pressure rollers 13, and one web preheating device 28. This state of use is the fifth
As shown in the figure, in addition to one web preheating device 28, two sets of heating rollers 12 and pressure rollers 13 are installed, or the web preheating device 28 is not used and one or more sets of heating rollers 12 and pressure rollers 13 are installed. It can be modified in various ways such as installation.

Next, the operation of the above embodiment will be explained.

According to the above-mentioned embodiment, the heating roller 12 generates heat in the circumferential wall of the roller body 18 due to the electric current being induced by the alternating magnetic flux generated by the magnetic flux generating section 23 by applying an alternating current voltage to the induction coil 22. The secret chamber 18A acts like a heat pipe to make the temperature of the peripheral wall of the roller body 18 uniform, and as a result, the surface temperature is constantly maintained at a uniform high temperature state.

Therefore, even when the web 1 with varying heat loads enters, the heating roller 12 applies a high contact pressure to the web 1 in the nip region N1 formed with the pressure roller 13, as shown in FIG. The web 1 is always thoroughly and intensely heated without being lifted from the heating roller 12. As a result, moisture in the web is very rapidly (explosively) converted into steam at the boundary with the heating roller 12, and this steam transfers free water in the web onto the porous support surface 11A of the transfer belt 11. A large amount will be transported to the side. Note that, as described above, the steam generated at the boundary with the heating roller 12 is dissipated into the atmosphere at the exit side of the heating roller 12 where the web 1 is released from the nip region N1. In FIG. 2, W is water, F is fiber, A is air, and V is vaporized water.

Therefore, according to the above embodiment, the water removal efficiency is extremely good, and the desired water removal work can be achieved with a small equipment space.

Further, according to the above embodiment, two pressure rollers 13 are used for one heating roller 12.
At the same time, the transfer belt 11 stretched between both pressure rollers 13 also pinches the web 1 between it and the heating roller 12 based on the tension of the transfer belt 11, thereby forming the above-mentioned nip region N1.
A quasi-nip region N2 is formed which performs substantially the same moisture removal function as in the above. Therefore, the water removal action by evaporating the water in the web by the thermal energy of the single heating roller 12 and carrying out the free water in the web by this steam is performed in the plurality of nip regions N1 and quasi-nip regions N2. As a result, one heating roller 1
The amount of water removed per unit 2 becomes large, and the water removal efficiency can be improved.

The nip pressure in each nip region N1 by each pressure roller 13 is independently set for each pressure roller 13 by the pressure adjustment cylinder 27, and the nip pressure in the quasi-nip region N2 by the transfer belt 11 is determined by the belt tension. Therefore, the nip pressure state of each of the plurality of nip regions N1 formed around the heating roller 12 and the nip pressure state of the quasi-nip region N2 can be adjusted independently.

Furthermore, the adjustment screw 26 adjusts the distance between the nip regions N1 formed by the pressure rollers 13.
It can be adjusted by Therefore, heating roller 1
The timing of the moisture removal action exerted on the web 1 by the plurality of nip regions N1 formed around the web 1;
Also, the length (time) of the quasi-nip region N2 can be adjusted.

That is, the nip pressure state of each nip region N1 and quasi-nip region N2 around the heating roller 12 can be adjusted independently, and the position of each nip region N1 and the length of the quasi-nip region N2 can be adjusted, and as a result, It is possible to variously adjust the water removal state around the heating roller 12 and improve the water removal performance.

In addition, in the case of the moisture removal device 10, the heating roller 12 has a built-in heating source (at this time,
The heating source is not limited to the induction heating method, but may be other means such as a resistance wire heating method),
Since no heating source is attached around the heating roller 12, two or more pressure rollers 13 can be easily installed in a wide range around the heating roller 12, and the mutual spacing between the rollers 13 can be adjusted in a wide range.

Further, in the above embodiment, the web 1 is entirely preheated including the front and back sides by the web preheating device 28.
, the above-mentioned heating roller 12 and each pressure roller 13
It will be introduced into the nip region N1 of. Therefore, the preheating device 28 can preheat the moisture in the web until just before evaporation, and the thermal energy of the heating roller 12 can be used more effectively for rapid and explosive steam conversion. The preheating device 28 can raise the temperature of the moisture in the web to lower its viscosity (dehydration resistance), and the above-mentioned moisture discharge resistance caused by the heating roller 12 can be reduced in advance. That is, this effectively complements the water removal effect of the present invention described above.

According to the experimental results on the papermaking line shown in Fig. 4, when the web conveyance speed is 150 m/min, the relationship between the inlet web moisture Win and the outlet web moisture Wout of the moisture removal device 10 is as shown in Fig. 6. It was hot.
In other words, the moisture content of the inlet web is 51%, while the moisture content of the outlet web is 24%.
3L was able to shorten the conventional 50-70m to 30-48m.
In other words, reduce the quantity of conventional dryer cells by 50-30%
It was recognized that the equipment space can be reduced by 40 to 20% compared to conventional methods.

Furthermore, in the paper making line shown in Fig. 5, the total length of the drying part 3, 3L, could be shortened to 10 to 15 m.
In addition, in FIGS. 4 and 5, 10L is the total length of the water removal device 10.

FIG. 7 is a schematic diagram showing another embodiment of the present invention. In FIG. 7, numeral 12 is a heating roller having the same structure as in the embodiment shown in FIG. This embodiment differs from the embodiment shown in FIG. 1 in that an independent transfer belt 100 is provided for each pressure roller 13. 16 is a support roller. Note that the transfer belt 100 may have three functions: a function of absorbing moisture in the web, a function of smoothing the web surface, and a function of withstanding tension.
The belt 100A may have the above functions, and the belt 100B may have the above functions.

Note that the heating roller of the present invention is not limited to one using the induction heating method as in the above embodiments, but may be of any heating method.

Further, the pressing device of the present invention may be in the form of a fixed shoe instead of in the form of a roller.

[Effects of the Invention] As described above, according to the present invention, the state of liquid removal around the heating roller can be adjusted in various ways, and the liquid removal performance can be improved.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a moisture removal device according to an embodiment of the present invention, FIG. 2 is a schematic diagram showing an enlarged main part of the moisture removal device, and FIG. 3 is a schematic diagram showing a heating roller. Figure 4 is a schematic diagram showing an example of applying the present invention to a paper making line, Figure 5 is a schematic diagram showing another example of applying the present invention to a paper making line, and Figure 6 is a line showing the water removal effect of the present invention. FIG. 7 is a schematic diagram showing another embodiment of the present invention, and FIG. 8 is a schematic diagram showing a conventional paper making line. 1... Web, 10... Moisture removal device, 11...
...Transfer belt, 11A...Supporting surface, 12...Heat roller, 13...Pressure roller, 26...Adjustment screw (nip position adjustment device), 27...Pressure adjustment cylinder (nip pressure adjustment device), 28 ...Web preheating device.

Claims (1)

[Scope of Claims] 1. A transfer belt that has a porous support surface and supports and transfers the web on the support surface; a heating roller that rotates in thermal contact with the web supported on the transfer belt; a pressure contact device that is in pressure contact with the back surface of the carrying surface that supports the web of the transfer belt and forms a nip area between the heating roller and the nip area that presses the transfer belt and the web; Heat is applied under high contact pressure to the web as it passes through the web, causing the liquid content in the web to rapidly convert to vapor, which penetrates the web and displaces any remaining free liquid within the porous structure of the transfer belt. In an apparatus for removing liquid from a web configured to be carried out to the supporting surface side, a plurality of pressure welding devices are each installed on each device along the outer periphery of the heating roller, and each nip area formed by each pressure welding device is The present invention is characterized in that a nip position adjustment device is provided that can adjust the mutual spacing, and a nip pressure adjustment device is provided that can independently adjust the nip pressure generated by each pressure welding device in its corresponding nip area. Liquid removal device for web. 2. The apparatus for removing liquid from a web according to claim 1, further comprising a web preheating device for preheating the entire web from both the front and back sides of the web, located upstream of the web line with respect to the nip area formed by the heating roller and the pressure contact device.