MACHINE FOR MANUFACTURING A STRIP OF TOILET PAPER

Abstract

The invention relates to a machine for manufacturing a paper web comprising: a Yankee dryer; a pressure cylinder in contact with the Yankee dryer; a support belt which carries the paper web; at least one suction cylinder, which is arranged upstream of the pressure cylinder and which is provided with a suction zone; at least one blow box, which partially surrounds the suction cylinder such that the support belt which carries the paper web is interposed between the suction cylinder and the blow box; and at least one hood, which at least partially surrounds the drying box and which is provided with a heating and air distribution system.The blower box is positioned below the suction cylinder, parallel to the paper web entering the suction cylinder, and partially surrounds the suction cylinder, partially covering the suction area. The hot, humid air blown by the blower box displaces and replaces the cold, dry air present on the paper web. This hot, humid air begins to condense and, as the paper web moves along the support belt, enters the suction area, passing through the paper web. This increases the paper's temperature by condensing most of its water vapor. (See Fig. 1 for abbreviations.)

Description

Title of the invention: MACHINE FOR MANUFACTURING A TOILET PAPER STRIP Technical field

[0001] The present invention relates to a machine for manufacturing a strip of toilet paper. Prior art

[0002] A machine for manufacturing a roll of toilet paper is disclosed, for example, in prior art document EP 2 896 743 Bl. In this machine, thermal energy is used to dry the paper and to wind it into rolls once finished. The thermal energy can be supplied in the form of pressurized steam, introduced into the so-called "Yankee" type drying cylinder, as well as fuel used by one or more burners. The thermal energy used increases or decreases depending on the amount of dry paper wound onto the Yankee dryer.

[0003] The paper is transferred to the Yankee dryer by a pressure cylinder arranged in contact with the lateral surface of the Yankee dryer. The pressure cylinder has two tasks: transferring the paper to the Yankee dryer, as mentioned above, and performing the final removal of water from the paper. This second task increases in efficiency as the paper temperature rises and the contact time between the Yankee dryer and the pressure cylinder lengthens. The pressure cylinder is preferably a deformable cylinder in the area of ​​contact with the Yankee dryer, so as to ensure a large contact surface. This type of press is commonly called a "shoe press."

[0004] The machine is also equipped with a suction cylinder. As mentioned above, with regard to the pressure cylinder, the suction cylinder is also more efficient at removing water from the paper with an increase in temperature. For this purpose, the suction cylinder can be supplied with at least some of the thermal energy available from the mist released into the atmosphere by the aerothermal system associated with the hood or half-hoods that enclose the Yankee dryer. In the machine shown in prior art document EP 2 896 743 Bl, this thermal energy is supplied to the suction cylinder through a blower box that covers the entire suction area provided on this suction cylinder.

[0005] The position of the blowing box covering the entire front part of the suction zone of the suction cylinder can however cause certain disadvantages. A The first drawback is that this blower box design soils the blower box's surface due to the release of loose paper fibers, particularly due to centrifugal force. This soiling causes frequent blower box downtime because the blower openings become clogged, necessitating scheduled cleaning. Another drawback is the potential for internal cleaning problems within the blower box due to residual paper fibers in the mist released by the air-heating system associated with the hood or half-hoods surrounding the Yankee dryer. Statement of the invention

[0006] Therefore, an object of the present invention is to provide a machine for the manufacture of a toilet paper type paper strip which is capable of overcoming the aforementioned disadvantages of the prior art in an extremely simple, economical and particularly functional manner.

[0007] In detail, an object of the present invention is to provide a machine for manufacturing a toilet paper-type paper strip that is capable of minimizing soiling of the blowing surface of the blowing box due to the release of free surface fibers from the paper.

[0008] Another object of the invention is to provide a machine for manufacturing a toilet paper-type paper strip that is capable of avoiding problems related to cleaning the inside of the blower box.

[0009] The present invention also aims to provide a machine for manufacturing a toilet paper-type paper strip that is capable of allowing precise control, through appropriate mist conditioning, of the blowing temperature of the blowing box.

[0010] These objectives according to the present invention are achieved by providing a machine for manufacturing a toilet paper-type paper roll, the machine comprising: -a rotary Yankee dryer; - at least one rotating pressure cylinder, which is equipped with a contact area with the outer lateral surface of the Yankee dryer; - at least one continuous and movable support belt, which is designed to carry the paper web across said contact area, so that in said contact area the paper web comes into contact with the outer side surface of the Yankee dryer; - at least one rotating suction cylinder, which is arranged upstream of the pressure cylinder so that, while the machine is running, the support belt comes into contact with said suction cylinder and the paper web is separated from some of the water contained therein, wherein said suction cylinder includes at least one suction zone which does not rotate with said suction cylinder and on which the support belt slides; - at least one blowing box, which partially surrounds the suction cylinder so that the support belt carrying the paper strip is interposed between said suction cylinder and said blowing box, in which said blowing box is designed to blow hot, humid air; and - at least one Yankee hood, which at least partially surrounds the Yankee dryer and which is provided with a heating and air distribution system, the machine being characterized in that the blowing box is positioned under the suction cylinder, parallel to the paper web entering said suction cylinder, and partially surrounds said suction cylinder by only partially covering said suction zone, so that the hot and humid air blown by the blowing box eliminates and replaces the cold and dry air present on the paper web, and so that said hot and humid air begins to condense and then, following the movement of the paper web on the support belt, enters the suction zone of the suction cylinder by passing through said paper web, so as to increase the temperature of said paper web by condensing at least part of its water vapor.

[0011] According to other characteristics taken alone or in combination: - the hot, humid air blown by the blower box is extracted by the Yankee hood through the heating and air distribution system and is supplied to said blower box through at least one duct which hydraulically connects said heating and air distribution system to said blower box; - the heating and air distribution system comprises at least one discharge duct for releasing the hot and humid air extracted by the Yankee hood into the atmosphere; - the pipe is hydraulically connected to said discharge conduit to reuse, in the blower box, the thermal energy available in the hot and humid air to be released into the atmosphere at the outlet of the heating and air distribution system; - along said pipe, close to the blowing box, is positioned at least one semi-open circulation purifier, which is designed to reduce the paper fibers present in said hot and humid air and to condition the temperature and the title of said hot and humid air; - along said pipe is positioned at least one variable speed fan, which is designed to control the flow rate of said hot and humid air; - the blowing box is provided with displacement means designed to position said blowing box at a variable distance from the paper web transported by the support belt, wherein said distance is variable within a range between 20 mm and 40 mm; - the Yankee hood includes a first half-hood and a second half-hood. Brief description of the drawings

[0012] The characteristics and advantages of a machine for manufacturing a strip of toilet paper type paper according to the present invention will emerge more clearly from the following description, by way of example and without limitation, with reference to the appended schematic drawings, in which:

[0013] [Fig-1] is a schematic side view of the main components of a machine for manufacturing a toilet paper type paper strip according to the present invention.

[0014] [Fig.2] is a schematic representation of a heating and air distribution system for a toilet paper web manufacturing machine according to the present invention. Detailed description of the invention

[0015] Referring to the figures, a preferred embodiment of a machine for manufacturing a toilet paper web according to the present invention is shown. The machine is indicated in its entirety by the reference numeral 10, while the toilet paper web being processed in the machine 10 is indicated by W.

[0016] In a manner known per se, the machine 10 comprises a rotary Yankee dryer 12, and at least one rotary pressure cylinder 14. The pressure cylinder 14 is provided with a contact zone N with the outer lateral surface of the Yankee dryer 12. The machine 10 further comprises at least one continuous and movable support belt 16, which is designed to transport the paper web W through the contact zone N of the pressure cylinder 14, so that in this contact zone N, the paper web W comes into contact with the outer lateral surface of the Yankee dryer 12.

[0017] The machine 10 also comprises at least one rotating suction cylinder 18, which is arranged upstream of the pressure cylinder 14 so that while the machine 10 is operating, the support belt 16 comes into contact with the suction cylinder 18 and the paper web W is separated from a portion of the water contained therein due to the suction action of the suction cylinder 1. For this purpose, the suction cylinder 18 comprises at least one suction zone 20 which does not rotate with the suction cylinder 18 and over which the support belt 16 passes.

[0018] The machine 10 further comprises at least one blowing box 22, which partially surrounds the suction cylinder 18 so that the support belt 16 which transports the paper web W is interposed between the suction cylinder 18 and the blowing box 22. This blowing box 22 is designed to blow hot and humid air, which is generally called "fog".

[0019] At least one Yankee hood 24 at least partially surrounds the Yankee dryer 12. In a manner known per se, the Yankee hood 24 is provided with a heating and air distribution system 26. As shown in the figures, the Yankee hood 24 preferably comprises a first half-hood 24A and a second half-hood 24B.

[0020] According to the invention, the blowing box 22 is positioned below the suction cylinder 18, parallel to the paper web W entering this suction cylinder 18, and it partially surrounds the suction cylinder 18 while only partially covering the suction zone 20. Thanks to this positioning of the blowing box 22, the hot and humid air blown by this blowing box 22 eliminates and replaces the cold and dry air present on the paper web W, so that this hot and humid air begins to condense and then, following the movement of the paper web W on the support belt 16, enters the suction zone 20 of the suction cylinder 18 by crossing the paper web W, so as to increase the temperature of the paper web W by condensing most of its water vapor.Furthermore, thanks to this positioning of the blow box 22 mainly in the linear translation zone of the paper strip W on the support belt 16, and only partially in the suction zone 20 of the suction cylinder 18, most of the paper fibers released and centrifuged by the movement of the paper strip W do not come into contact with the blowing zone of the blow box 22, eliminating the need for maintenance to remove the accumulation of paper fibers which could compromise the operation of the blow box 22.

[0021] Preferably, the warm, humid air blown by the blower box 22 is extracted by the Yankee hood 24 through the heating and air distribution system 26 and supplied to the blower box 22 through at least one duct 28 that hydraulically connects the heating and air distribution system 26 to the blower box 22. The heating and air distribution system 26 includes at least one exhaust duct 34 to release the warm, humid air extracted by the Yankee hood 24 into the atmosphere. Again, preferably, the pipe 28 is hydraulically connected to the exhaust duct 34 to reuse, in the blower box 22, the thermal energy available in the warm, humid air to be released into the atmosphere at the outlet of the heating and air distribution system 26.

[0022] Advantageously, along the duct 28, close to the blowing box 22, is positioned at least one semi-open circulation purifier 30, which is designed to reduce the paper fibers present in the hot and humid air and to condition the temperature (generally to a value of approximately 100°C) and the title (which is expressed in kg of water per kg of dry air) of this hot and humid air. In a known manner, a purifier is a piece of equipment which makes it possible to reduce the concentration of substances (generally consisting of powders, in the specific case, paper fibers) present in a gas stream (consisting of mist in the specific case). The positioning of the purifier 30 along the conduit 28 makes it possible to overcome the problems related to the internal cleaning of the blowing box 22, which would rather be necessary in the presence of residual paper fibers contained in the mist released by the heating and air distribution system 26. The presence of the purifier 30 further allows precise control of the blowing temperature of the blowing box 22. Since the heating of the paper web W occurs mainly by condensation of the water vapor contained in the mist, the latter will be proportionally abundant depending on the proximity of the temperature to the condensation.

[0023] Preferably, along the duct 28, it is possible to position at least one variable-speed fan 32, which is designed to control the flow rate of the hot, humid air. Also preferably, the blower box 22 can be equipped with means (not shown) designed to position the blower box 22 at a variable distance from the paper strip W carried by the support belt 16. This distance can vary within a range of 20 mm to 40 mm.

[0024] Therefore, it has been shown that the machine for manufacturing a toilet paper type paper web according to the present invention achieves the aims described above.

[0025] The machine for manufacturing a paper strip of the toilet paper type thus designed is in any case susceptible to various modifications and variants, all falling within the scope of the same innovative concept; furthermore, all details can be replaced by technically equivalent elements. Basically, the materials used, as well as the shapes and dimensions, can vary according to technical needs.

Claims

Claims

1. Machine (10) for manufacturing a paper web (W) of the toilet paper type, the machine (10) comprising: - a rotary Yankee dryer (12); - at least one rotating pressure cylinder (14), which is provided with a contact zone (N) with the outer side surface of the Yankee dryer (12); - at least one continuous and movable support belt (16), which is designed to transport the paper web (W) through said contact zone (N), so that in said contact zone (N), the paper web (W) comes into contact with the outer side surface of the Yankee dryer (12); - at least one rotating suction cylinder (18), which is arranged upstream of the pressure cylinder (14) so ​​that while the machine (10) is operating, the support belt (16) comes into contact with said suction cylinder (18) and the paper web (W) is separated from a part of the water contained therein, wherein said suction cylinder (18) comprises at least one suction zone (20) which does not rotate with said suction cylinder (18) and on which the support belt (16) slides; - at least one blowing box (22), which partially surrounds the suction cylinder (18) so that the support belt (16) which transports the paper web (W) is interposed between said suction cylinder (18) and said blowing box (22), wherein said blowing box (22) is designed to blow hot and humid air; and - at least one Yankee hood (24), which at least partially surrounds the Yankee dryer (12) and which is provided with a heating and air distribution system (26), the machine (10) being characterized in that the blowing box (22) is positioned under the suction cylinder (18), parallel to the paper web (W) entering said suction cylinder (18), and partially surrounds said suction cylinder (18) while only partially covering said suction zone (20), so that the hot and humid air blown by the blowing box (22) eliminates and replaces the cold and dry air present on the paper web (W), and so that said hot and humid air begins to condense and then, following the movement of the paper web (W) on the support belt (16), enters the zone suction cylinder (18) passing through said paper strip (W), so as to increase the temperature of said paper strip (W) by condensing at least part of its water vapor.

2. Machine (10) according to claim 1, characterized in that the hot and humid air blown by the blowing box (22) is extracted by the Yankee hood (24) through the heating and air distribution system (26) and is supplied to said blowing box (22) through at least one conduit (28) which hydraulically connects said heating and air distribution system (26) to said blowing box (22).

3. Machine (10) according to claim 2, characterized in that the heating and air distribution system (26) comprises at least one discharge duct (34) for releasing the hot and humid air extracted by the Yankee hood (24) into the atmosphere.

4. Machine (10) according to claim 3, characterized in that said pipe (28) is hydraulically connected to said discharge conduit (34) to reuse, in the blowing box (22), the thermal energy available in the hot and humid air to be released into the atmosphere at the outlet of the heating and air distribution system (26).

5. Machine (10) according to any one of claims 2 to 4, characterized in that along said pipe (28), in proximity to the blowing box (22), is positioned at least one semi-open circulation purifier (30), which is designed to reduce the paper fibers present in said hot and humid air and to condition the temperature and the title of said hot and humid air.

6. Machine (10) according to any one of claims 2 to 5, characterized in that along said pipe (28) is positioned at least one variable speed fan (32), which is adapted to control the flow rate of said hot and humid air.

7. Machine (10) according to any one of claims 1 to 6, characterized in that the blowing box (22) is provided with displacement means designed to position said blowing box (22) at a variable distance from the paper web (W) transported by the support belt (16), wherein said distance is variable in a range between 20 mm and 40 mm.

8. Machine (10) according to any one of claims 1 to 7, characterized in that the Yankee hood (24) comprises a first half-hood (24A) and a second half-hood (24B).

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