Machine for manufacturing paper web of toilet paper type

Abstract

Described herein is a machine for making a paper web of the toilet paper type, comprising: a Yankee dryer; a pressure roller in contact with the Yankee dryer; a support belt conveying the paper web; at least one suction roller arranged upstream of the pressure roller and provided with a suction area; at least one blow box; and at least one enclosure partially surrounding the drying oven and provided with an air heating and distribution system. The blowing box is positioned below the suction roller and is parallel to the paper web input on the suction roller, and partially surrounds the suction roller so as to partially cover the suction area, so that hot and humid air blown by the blowing box removes and replaces cold and dry air existing on the paper web, and the paper web is conveyed to the suction roller. And causing the hot and humid air to begin condensing and then enter into a suction region through the paper web as the paper web moves on the support belt to increase the temperature of the paper web, thereby condensing a majority of the water vapor of the hot and humid air.

Description

Technical Field

[0001] The utility model relates to a machine for manufacturing toilet paper type paper web material. Background Art

[0002] For example, prior art document EP 2896743 B1 discloses a machine for manufacturing paper webs of the toilet paper type. In this machine, thermal energy is used to dry the paper and to be able to wind it into rolls after completion. Thermal energy can be supplied in the form of pressurized steam introduced into a heating cylinder of the so-called "Yankee" type and in the form of fuel used by one or more burners. Depending on the dry part of the paper wound on the Yankee dryer, the thermal energy used increases or decreases.

[0003] The paper is transferred to the Yankee dryer by a pressure roller, which is arranged to be in contact with the lateral surface of such a Yankee dryer. The pressure roller has two tasks: to transfer the paper to the Yankee dryer, as described above, and finally to remove the water contained in the paper. The efficiency of this second task increases as the temperature of the paper increases and the contact period between the Yankee dryer and the pressure roller increases. Preferably, the pressure roller is a deformable roller at the contact area with the Yankee dryer to ensure a high contact surface. This type of compression is often called "shoe compression".

[0004] The machine is also provided with a suction roller. As mentioned above, with reference to the pressure roller, the suction roller is also more effective in its action of removing water from the paper as the temperature rises. For this purpose, the suction roller can be provided with at least a part of the thermal energy available on the mist released into the atmosphere by the aerodynamic heat system associated with the hood or half-hood wrapped around the Yankee dryer. In the machine shown in prior art document EP 2896743 B1, this thermal energy is supplied to the suction roller by means of a blow box which covers the entire suction area provided on such a suction roller.

[0005] However, the positioning of the blow box, which covers the entire front part of the suction zone of the suction roller, may lead to some disadvantages. A first disadvantage consists in the fact that this arrangement of the blow box causes the blowing surface of the blow box to become dirty due to the release of free-surface fibers of the paper, in particular due to the centrifugal effect. This dirtiness leads to frequent stops of the blow box due to the blockage of the blowing openings and the subsequent need to provide cleaning operations. Another disadvantage consists in that internal cleaning problems of the blow box may occur due to the presence of residual paper fibers contained in the water vapor released by the hood or half-hood associated with the hood wrapped around the Yankee dryer. Utility Model Content

[0006] The object of the present invention is therefore to provide a machine for manufacturing a paper web of the hygiene paper type which is able to overcome the above-mentioned disadvantages of the prior art in an extremely simple, cost-effective and particularly practical manner.

[0007] In detail, the object of the invention is to provide a machine for manufacturing a paper web of the hygiene paper type capable of minimizing the soiling of the blowing surface of the blow box due to the release of free-surface fibers of the paper.

[0008] Another object of the invention is to provide a machine for manufacturing a paper web of the hygiene type which avoids the problems associated with cleaning the interior of the blow box.

[0009] A further object of the invention is to provide a machine for manufacturing paper webs of the hygiene type which allows a precise control of the blowing temperature of the blow box by suitable regulation of the water vapor.

[0010] These objects according to the invention are achieved by providing a machine for manufacturing a paper web of the hygiene paper type as described in an embodiment of the invention.

[0011] Further features of the invention are outlined in further embodiments of the invention which form an integral part of the present description.

[0012] In some exemplary embodiments of the present invention, a machine for manufacturing a paper web of the toilet paper type is provided, the machine comprising: a rotating Yankee dryer; at least one rotating pressure roller, the pressure roller being provided with a contact area in contact with the outer lateral surface of the Yankee dryer; at least one continuous and movable support belt, the support belt being designed to transport the paper web through the contact area so that in the contact area, the paper web is in contact with the outer lateral surface of the Yankee dryer; at least one rotating suction roller, the suction roller being arranged upstream of the pressure roller so that when the machine is running, the support belt is in contact with the suction roller and the paper web is separated from a portion of the moisture contained in the paper web, wherein the suction roller comprises at least one suction area, the suction area does not rotate with the suction roller, and the support belt slides on the suction area; at least one blow box, the blow box partially surrounding around the suction roller so that the support belt conveying the paper web is placed between the suction roller and the blow box, wherein the blow box is designed to blow hot and humid air; and at least one Yankee hood, which at least partially surrounds the Yankee dryer and is provided with an air heating and distribution system, the blow box being positioned below the suction roller and parallel to the paper web input on the suction roller, and the blow box partially surrounds the suction roller so as to only partially cover the suction area so that the hot and humid air blown out by the blow box removes and replaces the cold and dry air present on the paper web and causes the hot and humid air to begin to condense, and then as the paper web moves on the support belt, the hot and humid air enters the suction area of ​​the suction roller passing through the paper web to increase the temperature of the paper web so as to condense at least a portion of the water vapor of the hot and humid air.

[0013] In some exemplary embodiments of the present invention, the hot and humid air blown out by the blowing box is extracted by the Yankee hood through the air heating and distribution system, and the extracted hot and humid air is supplied to the blowing box through at least one pipe, which hydraulically connects the air heating and distribution system to the blowing box.

[0014] In some exemplary embodiments of the present invention, the air heating and distribution system includes at least one exhaust duct for releasing the hot and humid air extracted by the Yankee hood into the atmosphere.

[0015] In some exemplary embodiments of the present invention, the duct is hydraulically connected to the exhaust duct to reuse the thermal energy available in the hot and humid air in the blow box, which is to be released into the atmosphere when leaving the air heating and distribution system.

[0016] In some exemplary embodiments of the present invention, at least one semi-open circulation scrubber is positioned along the duct, near the blow box, and the semi-open circulation scrubber is designed to reduce the presence of paper fibers in the hot and humid air and to regulate the temperature and titration of the hot and humid air.

[0017] In some exemplary embodiments of the present invention, at least one variable speed fan is positioned along the duct, the fan being designed to control the flow rate of the hot and humid air.

[0018] In some exemplary embodiments of the invention, the blow box is provided with a displacement device designed to position the blow box at a variable distance from the paper web conveyed by the support belt, wherein the distance can vary within a range comprised between 20 mm and 40 mm.

[0019] In some exemplary embodiments of the present invention, the Yankee shroud includes a first half shroud and a second half shroud. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The characteristics and advantages of the machine for manufacturing a paper web of the sanitary paper type according to the present invention will become more apparent from the following exemplary and non-limiting description with reference to the schematic drawings, in which:

[0021] Figure 1 is a schematic side view of the main parts of a machine for manufacturing a paper web of the toilet paper type according to the invention; and

[0022] Figure 2 It is a schematic diagram of an air heating and distribution system of a machine for manufacturing paper webs of the toilet paper type according to the present invention. DETAILED DESCRIPTION

[0023] Referring to the accompanying drawings, there is shown a preferred embodiment of a machine for manufacturing a paper web of a sanitary paper type according to the present invention. The machine is indicated as a whole by reference numeral 10, and the paper web of the sanitary paper type processed in the machine 10 is indicated by W.

[0024] In a manner known per se, the machine 10 comprises a rotating Yankee dryer 12 and at least one rotating pressure roller 14. The machine 10 also comprises at least one continuous and movable support belt 16 designed to transport the paper web W through a contact area N of the pressure roller 14 so that in this contact area N the paper web comes into contact with the outer lateral surface of the Yankee dryer 12.

[0025] The machine 10 further comprises at least one rotating suction roller 18, which is arranged upstream of the pressure roller 14, so that when the machine 10 is in operation, the support belt 16 comes into contact with the suction roller 18 and the paper web W is separated from a portion of the moisture contained in the paper web due to the suction action of the suction roller 18. To this end, the suction roller 18 comprises at least one suction area 20 which does not rotate with the suction roller 18 and over which the support belt 16 passes.

[0026] The machine 10 further comprises at least one blow box 22 which at least partially surrounds the suction roll 18 so that the support belt 16 conveying the paper web W is placed between the suction roll 18 and the blow box 22. The blow box 22 is designed to blow hot and humid air, which is usually called "moisture".

[0027] 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 an air heating and 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.

[0028] According to the present invention, the blow box 22 is positioned below the suction roller 18, parallel to the paper web W input on the suction roller 18, and the blow box 22 partially surrounds the suction roller 18, thereby only partially covering the suction area 20. Due to the positioning of the blow box 22, the hot and humid air blown out by the blow box 22 removes and replaces the cold and dry air existing on the paper web, so that the hot and humid air begins to condense, and as the paper web W moves on the support belt 16, it enters the suction area 20 of the suction roller 18 passing through the paper web W, so as to increase the temperature of the paper web W, thereby condensing most of the water vapor of the hot and humid air. Furthermore, still due to the positioning of the blow box 22 mainly in the linear translation area of ​​the paper web W on the support belt 16 and only partially in the suction area 20 of the suction roller 18, most of the paper fibers released and centrifuged by the movement of the paper web W do not impact the blowing area of ​​the blow box 22, thereby eliminating the need for maintenance in order to remove paper fiber accumulations that could endanger the function of the blow box 22.

[0029] Preferably, the hot and humid air blown out by the blowing box 22 is extracted by the Yankee hood 24 through the air heating and distribution system 26, and the extracted hot and humid air is supplied to the blowing box 22 through at least one duct 28, which hydraulically connects the air heating and distribution system 26 to the blowing box 22. The air heating and distribution system 26 comprises at least one exhaust duct 34 for releasing the hot and humid air extracted by the Yankee hood 24 into the atmosphere. Still preferably, the duct 28 is hydraulically connected to the exhaust duct 34 to reuse in the blowing box 22 the thermal energy available in the hot and humid air, which is to be released into the atmosphere when leaving from the air heating and distribution system 26.

[0030] Advantageously, along the duct 28, near the blowing box 22, at least one semi-open cycle scrubber 30 is positioned, designed to reduce the paper fibers present in the hot and humid air and for regulating the temperature (generally a value of about 100°C) and the titre (generally expressed in kilograms of water per kilogram of dry air) of this hot and humid air. As is known, a scrubber is a device that allows the concentration of substances (generally powders and in particular paper fibers) present in a gas stream (in particular water vapor) to be reduced. The positioning of the scrubber 30 along the duct 28 allows overcoming the problems associated with the internal cleaning of the blowing box 22, which would be necessary in the presence of residual paper fibers contained in the water vapor released by the air heating and distribution system 26. The presence of the scrubber 30 also allows the blowing temperature of the blowing box 22 to be precisely controlled. Assuming that the heating of the paper web W takes place primarily by condensation of water vapor contained in the water vapor, the water vapor contained in the water vapor will be abundant in proportion to how close the temperature is to condensation.

[0031] Preferably, at least one variable speed fan 32 designed to control the flow rate of the hot and humid air may be positioned along the duct 28. Still preferably, the blow box 22 may be provided with a displacement device (not shown) designed to position the blow box 22 at a variable distance from the paper web W transported by the support belt 16. This distance may vary within a range comprised between 20 mm and 40 mm.

[0032] It has thus been shown that the machine according to the invention for producing a paper web of the hygiene paper type achieves the above-mentioned objects.

[0033] The machine for manufacturing a paper web of the toilet paper type thus conceived of the invention is in any case susceptible to various modifications and variations, all of which fall within the same inventive concept; moreover, all the details may be replaced by technically equivalent elements. Basically, the materials used as well as the shapes and dimensions may vary according to technical requirements.

[0034] Therefore, the protection scope of the present invention is defined by the appended claims.

Claims

1. A 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 roller (14) provided with a contact area (N) with the outer lateral surface of the Yankee dryer (12); at least one continuous and movable supporting belt (16) designed to transport the paper web (W) through the contact area (N) so that in the contact area (N) the paper web (W) comes into contact with the outer lateral surface of the Yankee dryer (12); at least one rotating suction roller (18), which is arranged upstream of the pressure roller (14), so that when the machine (10) is in operation, the support belt (16) comes into contact with the suction roller (18) and the paper web (W) is separated from a portion of the moisture contained in the paper web (W), wherein the suction roller (18) comprises at least one suction area (20) which does not rotate with the suction roller (18) and the support belt (16) slides on the suction area (20); - at least one blow box (22) which partially surrounds the suction roller (18) so that the support belt (16) conveying the paper web (W) is placed between the suction roller (18) and the blow box (22), wherein the blow box (22) is designed to blow hot and humid air; and at least one Yankee hood (24) at least partially surrounding the Yankee dryer (12) and provided with an air heating and distribution system (26), The machine (10) is characterized in that the blow box (22) is positioned below the suction roller (18), parallel to the paper web input on the suction roller (18), and the blow box (22) partially surrounds the suction roller (18) so as to only partially cover the suction area (20), so that the hot and humid air blown out by the blow box (22) removes and replaces the cold and dry air present on the paper web (W), and causes the hot and humid air to begin to condense, and then as the paper web (W) moves on the support belt (16), the hot and humid air enters the suction area (20) of the suction roller (18) passing through the paper web (W) to increase the temperature of the paper web (W), thereby causing at least a portion of the water vapor in the hot and humid air to condense.

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

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

4. The machine (10) according to claim 3, characterized in that The duct (28) is hydraulically connected to the exhaust duct (34) to reuse in the blow box (22) the thermal energy available in the hot and humid air which is to be released into the atmosphere when leaving from the air heating and distribution system (26).

5. The machine (10) according to any one of claims 2 to 4, characterized in that At least one semi-open circulation scrubber (30) is positioned along the duct (28) near the blow box (22), the semi-open circulation scrubber (30) being designed to reduce the presence of paper fibers in the hot and humid air and to regulate the temperature and titration of the hot and humid air.

6. The machine (10) according to any one of claims 2 to 4, characterized in that At least one variable speed fan (32) is positioned along the duct (28), the fan (32) being designed to control the flow rate of the hot and humid air.

7. The machine (10) according to any one of claims 1 to 4, characterized in that The blow box (22) is provided with a displacement device designed to position the blow box (22) at a variable distance from the paper web (W) transported by the support belt (16), wherein the distance can be varied in a range comprised between 20 mm and 40 mm.

8. The machine (10) according to any one of claims 1 to 4, characterized in that The Yankee hood (24) comprises a first half hood (24A) and a second half hood (24B).

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