Household paper manufacturing equipment

Abstract

The embodiment of the utility model provides household paper manufacturing equipment, which is used for manufacturing thin paper webs and comprises a forming part, the pressing part comprises a pressing assembly, the pressing assembly comprises a first pressing roller, a second pressing roller and a first pressing area, and the pressing assembly applies first pressure to the wet paper web; a drying unit; the forming part further comprises a first blanket for supporting a wet paper web to pass through the first squeezing area, the squeezing part further comprises a second blanket for transferring a squeezed paper web formed after passing through the first squeezing area to a drying cylinder, the first pressure is 550-750 KN / m, the surface roughness Rz of the second blanket is smaller than or equal to 15 microns, and the surface roughness Rz of the first blanket is larger than or equal to 200 microns; and the ratio of the elastic modulus of the second blanket to the elastic modulus of the first blanket in the thickness direction is 1.5-3.5, so that on one hand, poor transfer can be reduced, on the other hand, the paper sheet crushing phenomenon can be reduced under the condition that the basis weight is extremely low, and the paper sheet quality is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of manufacturing equipment for manufacturing household paper. BACKGROUND

[0002] Household paper is widely used in people's daily life, with the improvement of living standards, people have higher and higher requirements on the softness, thickness, strength, touch / hand feeling of household paper, in order to take into account softness, touch / hand feeling, strength, thickness and other aspects of the requirements, more and more three-layer, four-layer tissue paper is formed into the form of multi-layer household paper.

[0003] At the same time, in order to make household paper have more thick and comfortable touch, technologies such as TAD (through-air drying) have been developed, after years of development, the technical defects such as high energy consumption of this technology are also paid more and more attention by the industry, and in order to further improve the performance of traditional DCT technology household paper, people combine TAD technology or modify the existing DCT technology to develop technologies such as NTT, ATMOS to realize lower energy consumption and make the paper get higher bulk.

[0004] These devices, such as CN103890264A, US6743339B1, are used for making household paper, but with the improvement of living standards, people have higher and higher requirements on the softness, thickness, strength, touch / hand feeling of household paper, in order to take into account softness, touch / hand feeling, strength, thickness and other aspects of the requirements, more and more three-layer, four-layer tissue paper is formed into the form of multi-layer household paper, which makes people have great demand for 8-13g / m2 low basis weight household paper, but the existing equipment is difficult to make these low basis weight household paper products, which is specifically shown in the following aspects:

[0005] I. When the basis weight is very low, the paper sheet after pressing is difficult to transfer, that is, after passing through the press roll, it is easy to transfer poorly from the first felt to the second felt and from the second felt to the drying cylinder.

[0006] II. Under the condition of very low basis weight, it is easy to cause paper sheet crushing or poor dewatering during pressing and dewatering.

[0007] An improved technical solution is needed to solve the above technical problems. CONTENT OF THE UTILITY MODEL

[0008] Therefore, the utility model provides a low basis weight household paper manufacturing equipment to solve the above technical problems.

[0009] A household paper manufacturing equipment for manufacturing tissue paper, comprising:

[0010] a forming section for forming a wet paper web;

[0011] a pressing section including a pressing assembly, the pressing assembly including a first pressing roll, a second pressing roll and a first pressing zone between the first pressing roll and the second pressing roll, the pressing assembly being configured to apply a first pressure to the wet paper web passing through the first pressing zone to form a pressed paper web;

[0012] a drying section including a drying cylinder for drying the pressed paper web to form a dried paper web and a doctor blade for creping the dried paper web to form a thin paper web;

[0013] the forming section further includes a first felt arranged around a plurality of first supporting rolls and the first pressing roll and supporting the wet paper web to pass through the first pressing zone, the pressing section further includes a second felt arranged around a plurality of second supporting rolls and the second pressing roll and transferring the pressed paper web formed after passing through the first pressing zone to the drying cylinder, and the first pressure is 550 KN / m to 750 KN / m.

[0014] a surface roughness Rz of the second felt is less than or equal to 15 μm, and a surface roughness Rz of the first felt is greater than or equal to 200 μm.

[0015] a ratio of the elastic modulus of the second felt to the elastic modulus of the first felt in the thickness direction is 1.5 to 3.5.

[0016] the second felt includes a base body and a plurality of groove portions arranged on the base body, and a density of the groove portions on a surface of the second felt is 50 to 100 per cm 2 a surface roughness Rz of the second felt is less than or equal to 15 μm refers to a surface roughness Rz of a region without the groove portions being less than or equal to 15 μm.

[0017] the groove portions have an area of 0.05 to 1.2 mm 2 the groove portions are circular.

[0018] the groove portions have a depth of 0.025 to 0.15 mm.

[0019] a total area of the groove portions accounts for 5% to 45% of a surface area of the second felt.

[0020] the first felt and the second felt have the same running speed, and the first pressing roll and the second pressing roll have the same running speed in opposite directions.

[0021] the first felt and the second felt are formed by stacking a plurality of structure layers, and the structure layers include a base layer and a surface layer, the base layer of the second felt is a metal layer or a rubber layer, and the surface layer of the second felt is a fabric layer.

[0022] The first pressure is 580KN / m to 650KN / m.

[0023] The pressing assembly is a roller press.

[0024] Beneficial Effects: This utility model provides a tissue paper manufacturing equipment for manufacturing thin paper webs, including: a forming section; a pressing section including a pressing assembly, the pressing assembly including a first pressing roller, a second pressing roller and a first pressing zone, the pressing assembly applying a first pressure to the wet paper web; a drying section; the forming section further includes a first blanket for supporting the wet paper web through the first pressing zone, the pressing section further includes a second blanket for transferring the pressed paper web formed after passing through the first pressing zone to the drying cylinder, and the first pressure is 550KN / m~750KN / m, the surface roughness Rz of the second blanket is ≤15μm, the surface roughness Rz of the first blanket is ≥200μm; the ratio of the elastic modulus of the second blanket to that of the first blanket in the thickness direction is 2.1~5.5. Through the above settings, on the one hand, the occurrence of transfer defects can be reduced, and on the other hand, the paper crushing phenomenon can be reduced under extremely low basis weight, thereby improving the paper quality. Attached Figure Description

[0025] Figure 1 A schematic diagram of a household paper manufacturing equipment according to an embodiment of this utility model;

[0026] Figure 2 for Figure 1 A schematic diagram of the pressing components;

[0027] Figure 3 A schematic diagram of the groove shape set on the substrate;

[0028] Component descriptions in the diagram:

[0029] Forming section 10; headbox 11; forming roll 12; forming zone 120; forming idler roll 13; forming net 14; first felt 15; first idler roll 16; pressing section 20; pressing assembly 21; first pressing zone 210; first pressing roll 211; second pressing roll 212; second idler roll 22; second felt 23; substrate 230; groove 231; heating device 24; transfer roll 25; second pressing zone 250; drying section 30; drying cylinder 31; air hood 32; doctor blade 33; wet paper web 401; pressed paper web 402; dried paper web 403; thin paper web 404. Detailed Implementation

[0030] Please refer to Figure 1 This utility model provides a tissue paper manufacturing equipment for manufacturing thin paper webs 404, more specifically, for manufacturing paper webs with a density of 8-13 g / m². 2thin paper web 404, while the thin paper web 404 is creped, formed by cellulose fibers, generally has a thickness of 60-200 μm, and has a bulk of 6-20 cm 3 / g, MDT is in the range of 40-200 N / m, and CDT is in the range of 20-180 N / m.

[0031] The tissue paper manufacturing apparatus comprises a forming section 10, a press section 20 and a drying section 30.

[0032] The forming section 10 comprises a headbox 11, a forming roll 12, a forming wire 14 and a first felt 15, wherein the headbox 11 is configured to spray the cellulose fiber suspension onto the forming wire 14, the forming roll 12 is at least partially covered by the first felt 15 and is configured to dewater the cellulose fiber suspension, the first felt 15 is in the form of an endless loop, at least a portion of which is wrapped around the forming roll 12 and is configured to support the movement of the wet paper web 401, and the forming wire 14 is at least partially attached to the first felt 15 wrapped around the forming roll 12 to form a nip, and the cellulose fiber suspension is dewatered by the nip to form the wet paper web 401.

[0033] It can be understood that, on one side of the nip, the forming wire 14 and the first felt 15 form a forming zone 120, the headbox 11 comprises a plurality of nozzles configured to spray the cellulose fiber suspension, the nozzles are located in the forming zone 120, and the cellulose fiber suspension is sprayed onto the forming wire 14, generally, the position where the cellulose fiber suspension is sprayed onto the forming wire 14 is referred to as the landing point, and it can be understood that the landing point is spaced apart from the nip.

[0034] It can be understood that the forming wire 14 is wrapped around a plurality of forming rolls 13 and is in the form of an endless loop, so that the forming wire 14 circulates, and the first felt 15 is wrapped around a plurality of first rolls 16 and is in the form of an endless loop.

[0035] The press section 20 is arranged downstream of the forming section 10 and comprises a press assembly 21, the press assembly 21 comprises a first press roll 211, a second press roll 212 and a first press nip 210 between the first press roll 211 and the second press roll 212, and the press assembly 21 is configured to apply a first pressure to the wet paper web 401 passing through the press nip to form a press paper web 402.

[0036] It can be understood that, in the embodiment, the press assembly 21 is a roll press, that is, the first press roll 211 and the second press roll 212 are both rolls with cladding layers, which can be polyurethane cladding layers. In other embodiments, the press assembly 21 is a shoe press, in which the second press roll 212 is a rigid or cladded roll, and the first press roll 211 includes a shoe, a belt wrapped around the shoe, a roll driving the belt, and an application assembly inside the shoe and applying pressure to the shoe.

[0037] The press section 20 further includes a second felt 23 wrapped around the second rolls 22 and the second press roll 212, which passes through the first press zone 210 and transfers the press web 402 formed after passing through the first press zone 210 to the downstream direction.

[0038] It can be understood that the second felt 23 also has a loop shape so as to be circulated.

[0039] It can be understood that the first felt 15 also passes through the first press zone 210, and the first felt 15 and the second felt 23 form a clamping mode to the wet web 401 in the press zone. When the press assembly 21 applies the first pressure in the press zone, the water on the wet web 401 is squeezed to form dewatering, and after passing through the first press zone 210, the wet web 401 is transferred from the first felt 15 to the second felt 23 and moves with the second felt 23. It can be understood that the wet web 401 after passing through the first press zone 210 is called the press web 402. Preferably, the dryness of the wet web 401 is 15-30%, and the dryness of the press web 402 is 45-65%.

[0040] The first felt 15 and the second felt 23 can be elastically deformed in the thickness direction and can be compressed. At the same time, the ratio of the elastic modulus of the second felt 23 to the first felt 15 in the thickness direction is 1.5-3.5, that is, when being squeezed by the first pressure at the same time, the deformation of the first felt 15 in the thickness direction is greater than that of the second felt 23. At the same time, in order to make the press web 402 have sufficient dryness, the first pressure is 550 KN / m-750 KN / m. It can be understood that the first pressure is a linear pressure.

[0041] The research finds that, on the one hand, the linear pressure in the first pressure range of 550KN / m~750KN / m can make the low basis weight household paper reach sufficient dryness, especially for the lower basis weight household paper, such as less than 9g / m2, the first pressure is preferably 580KN / m~650KN / m, so that the dryness is in the appropriate range, such as less than 55% dryness, so that the wet paper web 401 has sufficient surface tension between the second felt 23 and the first felt 15 to smoothly transfer from the first felt 15 to the second felt 23.

[0042] On the other hand, under the above pressure, the elastic deformation of the second felt 23 and the first felt 15 in the thickness direction will be in the appropriate range, and at the same time, due to the first pressure roller as a force applying unit, the first felt 15 and the wet paper web 401 form a slight bending deformation in the direction of the first pressure roller during the force process, so that the low basis weight household paper is not easy to appear crushing phenomenon, especially for the lower basis weight household paper, such as 8.0~9.0g / m2 wet paper web 401, due to its lower paper thickness, the ratio of the elastic modulus of the second felt 23 and the first felt 15 needs to be larger to not easily appear crushing and have appropriate bulkiness. The research finds that, compared with the prior art, for 9.0g / m2 basis weight household paper, the above setting mode makes the crushing phenomenon average decrease by 17%.

[0043] In addition, due to the low basis weight of the low basis weight household paper, the thickness is low, so that the fibers on the corresponding area actually bear more pressure, when the second felt 23 and the first felt 15 with higher elastic modulus ratio are used, the pressure can be reduced, so that the fibers are not easy to appear discrete phenomenon, that is, the damage problem in the pressing process is also reduced.

[0044] In addition, the second felt 23 is relatively delicate compared with the first felt 15, specifically, the surface roughness Rz of the second felt 23 is ≤15μm, and the surface roughness Rz of the first felt 15 is ≥200μm, so that the low basis weight household paper can be smoothly transferred from the first felt 15 to the second felt 23 after passing through the first pressing area 210. It can be understood that the surface roughness refers to the surface roughness of the first felt 15 and the second felt 23 under the condition of not being compressed.

[0045] Further, the forming part 10 is also provided with a plurality of auxiliary dewatering devices, usually, the auxiliary dewatering device can be a vacuum dewatering roller or a vacuum dewatering box, more specifically, the vacuum dewatering box has an adsorption space communicated with a negative pressure device, the adsorption space includes an adsorption port adjacent to and facing the first felt 15, and the water in the first felt 15 and the wet paper web 401 is adsorbed and collected by the adsorption port and discharged, thereby improving the dryness of the wet paper web 401 before entering the first pressing area 210.

[0046] Further, the press section 20 can be provided with a heating device 24 configured to increase the dryness of the press web 402 by passing a hot gas stream through the press web 402, which can be a high temperature steam or hot air stream.

[0047] Further, the heating device 24 comprises a hot gas stream box and an adsorption box opposite to the hot gas stream box, the hot gas stream box and the adsorption box are respectively arranged outside the press web 402 and inside the second felt 23, the hot gas stream box comprises a gas stream opening, the adsorption box comprises an adsorption opening, the hot gas stream flows from the gas stream opening to the adsorption opening after passing through the press web 402 and the second felt 23, in this case, on the one hand, the dryness of the press web 402 can be further increased, and the energy consumption of the subsequent drying section 30 can be reduced, on the other hand, the press web 402 can be kept adhered to the second felt 23 to run.

[0048] The drying section 30 comprises a drying cylinder 31 for drying the press web 402 to form a dried web 403 and a doctor blade 33 for creping the dried web 403 to form a tissue web 404.

[0049] It can be understood that the drying cylinder 31 comprises an outer drying surface for adhering and drying the press web 402, the press section 20 further comprises a transfer roller 25 for adhering the second felt 23 to the outer drying surface, and the transfer roller 25 applies a pressure to the drying cylinder 31 to form a second press zone 250, the press web 402 is adhered and transferred to the outer drying surface after passing through the second press zone 250.

[0050] It can be understood that the transfer roller 25 is located inside the second felt 23 to form an adhesion between the outer side of the second felt 23 and the outer drying surface, so that the press web 402 is transferred to the outer drying surface.

[0051] Further, in order to easily transfer the press web 402 to the outer drying surface, the outer drying surface has a smooth surface, and additionally, a viscous material such as a cylinder paste can be sprayed on the outer drying surface.

[0052] The doctor blade 33 is arranged downstream of the drying cylinder, and at least one part of the doctor blade 33 is adhered to the outer drying surface, so that the dried web 403 formed by the adhesion is impacted on the doctor blade 33 to form creases, and finally the tissue web 404 with creases is formed.

[0053] The doctor blade 33 can be made of steel, hard alloy or hard ceramic material, which is not limited here.

[0054] In addition, the dryer 31 can be provided with or without a gas cover 32. When the dryer 31 is provided with the gas cover 32, the gas cover 32 is in a negative pressure state. In other words, when the dryer 31 is provided with the gas cover 32, no medium, such as high-temperature steam or hot air, is introduced into the gas cover 32 for drying the pressed paper web 402. In this case, the gas cover 32 is used for recovering heat. In detail, the heat radiation of the surface of the dryer 31 heats the air adjacent to the outer drying surface and the water vapor generated by the evaporation of the water in the pressed paper web 402, which is collected by the gas cover 32 and then extracted. It can be understood that the hot air collected by the gas cover 32 can be reused in other areas, such as the heating device 24 or the dryer 31 after being heated again. In this case, the gas cover 32 is connected to a reuse device. The reuse device includes a negative pressure device and a pipeline system connected to the negative pressure device and the gas cover 32. The pipeline system includes a blowing device.

[0055] Further, the pipeline system is connected to the heating device 24 and the dryer 31.

[0056] Further, the negative pressure in the gas cover 32 is less than or equal to -0.1 KPa.

[0057] Please refer to Figure 2 and Figure 3 The second felt 23 includes a base body 230 and a plurality of groove portions 231 arranged on the base body 230. The density of the groove portions 231 on the surface of the second felt 23 is 50-100 per cm 2 The density refers to the number of groove portions 231 per unit area. When the second felt 23 is provided with the groove portions 231, the surface roughness Rz of the second felt 23 in the area without the groove portions 231 is less than or equal to 15 μm.

[0058] Preferably, the distribution density of the groove portions 231 on the surface of the second felt 23 is 60-90 per cm 2 .

[0059] Further research shows that when the density of the groove portions 231 is higher, the pressure on the wet paper sheet is reduced, so that the formed paper sheet has a higher surface smoothness. However, the water extrusion effect on the paper sheet is reduced at this time. When the density of the groove portions 231 is lower, the pressure on the wet paper sheet is increased, which may cause the paper sheet to be damaged. Preferably, the density of the groove portions 231 is inversely proportional to the basis weight of the paper sheet. In other words, a lower basis weight requires a higher density of the groove portions 231, and a higher basis weight requires a lower density of the groove portions 231.

[0060] Further, the groove portions 231 have a depth of 0.05-1.2 mm 2The recessed part 231 is circular in a preferred embodiment.

[0061] Further, the recessed part 231 has a depth of 0.025-0.15 mm.

[0062] Further, the total area of the recessed part 231 accounts for 5-45% of the surface area of the second felt 23, and more preferably 6-18%.

[0063] Further, the first felt 15 and the second felt 23 have the same running speed, and the first press roller 211 and the second press roller 212 have the same running speed but in opposite directions.

[0064] Further, the first felt 15 and the second felt 23 are made of polymer material, such as polyurethane, or are formed by laminating a plurality of structure layers. When the first felt 15 and the second felt 23 include a plurality of structure layers, the structure layers include a base layer and a surface layer. The base layer of the second felt 23 is preferably a metal layer or a rubber layer, and the surface layer is a fabric layer.

[0065] In some cases, the base layer is also provided with through holes, so that the second felt 23 has good water permeability, and because the surface layer is a fabric, the surface layer has good smoothness.

[0066] The above description is only an embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process conversion, or direct or indirect application in other related technical fields, is also included in the patent protection scope of the present application.

Claims

1. A device for manufacturing household paper, used to manufacture thin paper sheets, characterized in that, include: The forming section is used to form the wet paper web; The pressing section includes a pressing assembly, the pressing assembly including a first pressing roll, a second pressing roll and a first pressing zone located between the first pressing roll and the second pressing roll, the pressing assembly being configured to apply a first pressure to a wet paper web passing through the pressing zone to form a pressed paper web; The drying section includes a drying cylinder for drying the press paper web to form a dry paper web and a doctor blade for creping the dry paper web to form a thin paper web; The forming section further includes a first blanket wound around a plurality of first idler rollers and a first press roller and supporting the wet paper web as it passes through the first press zone. The pressing section further includes a second blanket wound around a plurality of second idler rollers and a second press roller and transferring the pressed paper web formed after passing through the first press zone to the drying cylinder. The first pressure is 550KN / m to 750KN / m. The surface roughness Rz of the second blanket is ≤15μm, and the surface roughness Rz of the first blanket is ≥200μm; The ratio of the elastic modulus of the second blanket to that of the first blanket in the thickness direction is 1.5 to 3.

5.

2. The tissue paper manufacturing equipment as described in claim 1, characterized in that, The second blanket includes a base and a plurality of grooves disposed on the base, wherein the density of the grooves on the surface of the second blanket is 50 to 100 per cm. 2 The surface roughness Rz≤15μm of the second blanket refers to the surface roughness Rz≤15μm in the area where no groove is provided.

3. The tissue paper manufacturing equipment as described in claim 2, characterized in that, The groove portion has a diameter of 0.05–1.2 mm. 2 The area of ​​the groove is circular.

4. The tissue paper manufacturing equipment as described in claim 3, characterized in that, The depth of the groove is 0.025 to 0.15 mm.

5. The tissue paper manufacturing equipment as described in claim 4, characterized in that, The total area of ​​the groove portion accounts for 5% to 45% of the surface area of ​​the second blanket.

6. The tissue paper manufacturing equipment as described in claim 2, characterized in that, The first and second blankets run at the same speed, and the first and second press rollers run at the same speed but in opposite directions.

7. The tissue paper manufacturing equipment as described in claim 1, characterized in that, The first blanket and the second blanket are formed by stacking several structural layers, the structural layers including a base layer and a surface layer, wherein the base layer of the second blanket is a metal layer or a rubber layer, and the surface layer of the second blanket is a fabric layer.

8. The tissue paper manufacturing equipment as described in claim 1, characterized in that, The first pressure is 580KN / m to 650KN / m.

9. The tissue paper manufacturing equipment as described in claim 1, characterized in that, The pressing assembly is a roller press.

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