CN218910971U

CN218910971U - Efficient Yankee hood

Info

Publication number: CN218910971U
Application number: CN202221280394.7U
Authority: CN
Inventors: 卢卡·利纳里; 马尔科·卡塔尼
Original assignee: Andritz AG
Current assignee: Andritz AG
Priority date: 2021-05-25
Filing date: 2022-05-24
Publication date: 2023-04-25
Anticipated expiration: 2032-05-24
Also published as: DE202022001142U1; FR3123423B3; IT202100002777U1; FR3123423A3

Abstract

Described is an efficient yankee hood for a facility for producing web-like paper material starting from a pulp of paper material to be dewatered. The yankee hood is operatively associated with a rotating yankee cylinder supplied with pressurized steam, to which a slurry of paper material to be dewatered dynamically adheres. The yankee cover includes at least one housing that in turn includes: at least one inner wall having a circumferential arc shape in vertical cross section and designed to at least partially surround the rotary yankee cylinder; at least one upper wall; and at least one side wall. The yankee hood (10) further comprises at least one duct for introducing/distributing air to the rotating yankee cylinder and at least one duct for extracting/recovering air from the rotating yankee cylinder. At least one of a duct for introducing/distributing air to the rotary yankee cylinder and a duct for extracting/recovering air from the rotary yankee cylinder is positioned outside the housing.

Description

Efficient Yankee hood

Technical Field

The present utility model relates generally to an apparatus for producing web-like sheet material and, more particularly, to an improved Gao Xiaoyang g cover for an apparatus for producing web-like sheet material.

Background

It is well known that in paper production processes in general, and in tissue paper production in particular, a step of drying the treated product by evaporation must be carried out in order to extract the excess water content of the product. The product to be dewatered, which is usually composed of a fibre pulp based on cellulose and diluted with water, is initially prepared in a suitable forming apparatus and is therefore transported after an intermediate vacuum extraction step to a subsequent drying and dewatering apparatus. At the inlet of the drying and dewatering equipment, the slurry forming the treated paper contains a lower dry fraction content, which may be equal to about 24% to about 28%. In other words, the slurry may still contain up to 60% or more water after the vacuum extraction step and further extraction in the extrusion machine. Thus, the vacuum extraction step cannot eliminate all the water in the pulp fibers, and therefore this water must be removed by evaporation.

End products, which are typically but not entirely made of tissue paper, require a dry fraction content well above the values described above, typically equal to about 94% to about 98%. It is therefore apparent that there is a need to extract a large part of the residual water content from the fibre pulp by evaporation in the drying step in order to obtain a sufficiently dry continuous paper. After the drying and dewatering steps by evaporation, the sheet is stored in reels for subsequent processing (the so-called "converting" step), and finally packaged for shipping and final retail sales.

The most common drying and dewatering equipment in paper production facilities, in particular toilet paper production facilities, comprises two separate drying devices, but even if both devices act simultaneously on the web-shaped paper material to be treated, these web-shaped paper material is still in the state of the fibrous slurry to be dewatered. The first drying apparatus includes one or more high efficiency "yankee" hoods that blow hot air, typically at a temperature between 180 ℃ and 650 ℃, onto the fiber slurry being dried. While blowing, the dried fiber slurry is contacted with the side surface of at least one steam heated cylinder, typically having a diameter in the range of between about 1.5m and about 6 m. Such cylinders, commonly referred to as "yankees", typically include a pressurized vessel containing process steam therein at a pressure ranging typically between about 4bar G and about 10bar G.

Current high efficiency yankee hoods coupled with yankee cylinders used to produce crepe papers of the tissue type are typically divided into two parts. The first yankee hood portion, or first yankee hood half, is positioned at an inlet portion of the dried fiber slurry into the yankee cylinder. The second yankee hood portion, or second yankee hood half, is then positioned at an outlet portion where the dried fiber slurry exits from the yankee cylinder. The two yankee halves are laterally connected by at least one duct for introducing/distributing air and at least one duct for extracting/recovering air. This thus allows a semi-closed loop to be formed where air at a height Wen Chuisong is recovered along with the evaporated water after a sensitive heat exchange with the dried fibre pulp, so that the air is recirculated after a new heating.

In this type of yankee hood, the ducts for introducing/distributing air continue to be located in the yankee hood, allowing the distribution of the blown air on the dried fibre pulp using control means constituted, for example, by manual or motor-driven gates. Instead, the recovery air is extracted by placing the entire yankee hood in vacuum without actually controlling the recovery profile, but rather by relying on the low velocity air allowed by the large internal volume provided by the yankee hood. Thus, this is detrimental to some portions of the yankee hood that cannot provide such large internal volumes, such as, for example, end portions or tail portions of the yankee hood that are aspects of both input and output of the dried fiber slurry. These end or tail portions do not actually provide a particularly large internal volume due to their particular tapered shape.

However, there is a lot of available volume in the yankee hoods of the type described above at present, which causes some drawbacks. The first disadvantage lies in the fact that, in the case of application to yankee cylinders having a large diameter, illustratively greater than 12 feet (equal to about 3.66 meters), transport difficulties can occur when transporting a conventional whole yankee hood. Therefore, the yankee hood must be transported in several parts, assembled by welding on site, which is both technically and functionally difficult.

Another disadvantage of the current yankee hoods of the above-mentioned type is the fact that the insertion of the ducts for introducing/distributing air into the yankee hood, which is not normally insulated, causes thermal inefficiency, as part of the heat migrates through the walls of the ducts for introducing/distributing air towards the return air without contributing to the evaporation of the paper.

Another drawback of the current yankee hoods of the above-mentioned type consists in the fact that the ducts arranged in the yankee hood for introducing/distributing the air present an obstacle to the free circulation of the recovered air, basically the ducts do not make the vacuum inside the yankee hood uniform-this ensures the recovery over the whole blowing surface. In fact, the vacuum value in the yankee hood is very low, on the order of tens of N/m ² Thereby avoiding a lot of cold air from penetrating from the machine room.

Disclosure of Invention

It is therefore an object of the present utility model to provide an improved Gao Xiaoyang g hood for a plant for producing web-like paper material, which hood is capable of overcoming the above-mentioned drawbacks of the prior art in an extremely simple, cost-effective and particularly practical manner.

In detail, it is an object of the present utility model to provide an improved Gao Xiaoyang g cover which is smaller in size and volume than similar yankee covers according to the prior art, thereby having advantages in terms of ease of transportation and assembly.

It is a further object of the present utility model to provide an improved Gao Xiaoyang g cover which also has a higher thermal efficiency than similar yankee covers according to the prior art.

These objects according to the utility model are achieved by providing an improved Gao Xiaoyang g cover for a plant for producing web-like paper material according to the utility model.

Additional features of the utility model are summarized by the detailed description of the utility model that forms part of this specification.

Drawings

The features and advantages of the improved Gao Xiaoyang g cover according to the utility model will be apparent from the following exemplary and non-limiting description, with reference to the accompanying schematic drawings, wherein the only figure 1 is a schematic side cross-sectional view of a portion of the improved Gao Xiaoyang g cover according to the utility model.

Detailed Description

Referring to fig. 1, there is shown a preferred embodiment of a modified Gao Xiaoyang g cover in accordance with the present utility model. The yankee hood is generally indicated by reference numeral 10.

The yankee hood 10 is designed to be used in a known type of installation for producing web-like paper material starting from a pulp of paper material to be dewatered. Therefore, such facilities of a known type will not be described and illustrated in this document. Still in a manner known per se, the yankee hood 10 is operatively associated with a rotating yankee cylinder 14 supplied with pressurized steam, on which cylinder 14 a slurry of paper material to be dewatered dynamically adheres.

In the embodiment shown in fig. 1, by way of example only, the yankee hood 10 includes a first yankee hood half and a second yankee hood half (not shown) that is generally symmetrical about the first yankee hood half in a plane perpendicular to the side surfaces of the rotating yankee cylinder 14. The first yankee half cover and the second yankee half cover are each capable of blowing dry air at a high temperature onto the sheet material slurry wrapped around the side surfaces of the rotary yankee cylinder 14, and of sucking moist heat air released from the sheet material slurry. Preferably, the Yankee hood 10 may be designed to blow dry air at a temperature of between about 180℃ and about 650℃ and at a velocity of between about 100m/s and about 150 m/s.

Regardless of the embodiment, the yankee hood 10 includes at least one housing 12, which housing 12 in turn includes: at least one inner wall 16, the at least one inner wall 16 having a circumferential arcuate shape in vertical cross section, the at least one inner wall 16 being designed to at least partially enclose the rotary yankee cylinder 14; at least one upper wall 18; and at least one side wall 20. The yankee hood 10 further includes: at least one first duct 22 for introducing/distributing air to the rotary yankee cylinder 14; and at least one second duct 24 for extracting/recovering air from such a rotating yankee cylinder 14.

According to the present utility model, at least one of the first duct 22 for introducing/distributing air to the rotary yankee cylinder 14 and the second duct 24 for extracting/recovering air from the rotary yankee cylinder 14 is positioned outside the housing 12. Preferably, as shown in fig. 1, both the first duct 22 for introducing/distributing air to the rotary yankee cylinder 14 and the second duct 24 for extracting/recovering air from the rotary yankee cylinder 14 are positioned outside the housing 12.

Based on the embodiment of the yankee hood 10 shown in fig. 1, a first duct 22 for introducing/distributing air to the rotary yankee cylinder 14 and/or a second duct 24 for extracting/recovering air from the rotary yankee cylinder 14 are positioned at the upper wall 18 of the housing 12. However, it cannot be excluded that the first duct 22 for introducing/distributing air to the rotary yankee cylinder 14 and/or the second duct 24 for extracting/retrieving air from the rotary yankee cylinder 14 may be positioned at other parts of the housing 12 but still outside the housing 12.

Advantageously, the at least one first duct 22 for introducing/distributing air to the rotary yankee cylinder 14 may be provided with an external tubular surface that is at least partially thermally insulated. Similarly, the second conduit 24 for extracting/recovering air from the rotary yankee cylinder 14 may also be provided with an outer tubular surface that is at least partially thermally insulated.

The housing 12 of the yankee hood 10 may be internally provided with at least one

distribution partition wall

26, 28, which at least one

distribution partition wall

26, 28 is hydraulically connected to the first conduit 22 for introducing/distributing air, and which at least one

distribution partition wall

26, 28 is designed to distribute air in a controlled manner through the inner wall 16 of the housing 12 towards the rotating yankee cylinder 14. Preferably, each of the

distribution partition walls

26, 28 may be provided with one or more control gates 30, the one or more control gates 30 being used to control the distribution of air to the rotary yankee cylinder 14. The control door 30 may be either a manual type or a motor-driven type.

The inside of the housing 12 of the yankee hood 10 may also be provided with at least one vacuum-operated chamber 32, which at least one vacuum-operated chamber 32 is hydraulically connected to the second conduit 24 for extracting/recovering air. The at least one vacuum operated chamber 32 is designed for: air is recovered from the rotary yankee cylinder 14 through the inner wall 16 of the housing 12 and is conveyed to a second duct 24 for extraction/recovery of air.

Based on the embodiment of the yankee hood 10 shown in fig. 1, the first duct 22 for introducing/distributing air to the rotary yankee cylinder 14 and/or the second duct 24 for extracting/recovering air from the rotary yankee cylinder 14 are ducts having a circular cross section. Furthermore, the first duct 22 for introducing/distributing air to the rotary yankee cylinder 14 and/or the second duct 24 for extracting/recovering air from the rotary yankee cylinder 14 may be provided with

respective support frames

34, 36, which support

frames

34, 36 are integrally joined with at least one of the inner wall 16 and/or the upper wall 18 of the housing 12, preferably, which support

frames

34, 36 are integrally joined with the upper wall 18 of the housing 12.

At least one first duct 22 for introducing/distributing air to the rotating yankee cylinder 14, which first duct 22 may also be thermally insulated, is positioned outside the yankee hood 10, which allows to overcome the drawbacks outlined above of the yankee hood according to the prior art. The first duct 22 for introducing/dispensing air may effectively interface with an internal air dispensing mechanism of the yankee hood 10, for example, including dispensing

partition walls

26, 28 having a suitable manual or motor-driven door 30.

Conversely, the recovery of air from the yankee hood 10 may also be performed by a second duct 24 for extracting/recovering air from the rotating yankee cylinder 14, which second duct 24 is also positioned outside the yankee hood 10 and may be thermally insulated. The second duct 24 for extracting/recovering air may comprise one or more dendrites for ensuring a correct extraction of the return air, thus minimizing the internal vacuum value and thus the return of cold air from the machine room through the open part of the yankee hood 10, such as for example the part for inputting and outputting the paper, i.e. the end or tail part of the yankee hood 10 that interfaces with the rotating yankee cylinder 14.

Thus, the solution according to the utility model allows to drastically reduce the overall volume of the yankee hood 10, allowing to transport the yankee hood 10 applied to a rotating yankee cylinder 14 measuring up to 15 feet (equal to about 4.57 meters) and even up to 18 feet (equal to about 5.49 meters) as a single piece. Thus, overcoming the functional drawbacks outlined above would allow to obtain a more efficient yankee hood, wherein it can be estimated to save about 3% heat compared to similar yankee hoods according to the prior art.

It has thus been observed that the object outlined above is achieved by a modified Gao Xiaoyang g cover of a plant for producing web-like paper material according to the utility model.

The modified Gao Xiaoyang g cover of the installation for producing web-like paper material thus conceived is susceptible in any case of various modifications and variants, all falling within the same inventive concept; furthermore, all the details may be replaced with technically equivalent elements. Basically, the materials used, as well as the shapes and dimensions, may vary according to technical needs.

Accordingly, the scope of the utility model is defined by the appended claims.

Claims

1. An efficient yankee hood (10) for a facility for producing web-like sheet material starting from a pulp of sheet material to be dewatered, characterized in that said yankee hood (10) is operatively associated with a rotating yankee cylinder (14) supplied with pressurized steam, said pulp of sheet material to be dewatered being dynamically adhered to said rotating yankee cylinder (14), said yankee hood (10) comprising at least one housing (12), said housing (12) in turn comprising:

-at least one inner wall (16), the inner wall (16) having a circumferential arc shape in vertical cross section, the inner wall (16) being designed to at least partially enclose the rotating yankee cylinder (14);

at least one upper wall (18); and

at least one side wall (20);

the yankee hood (10) further comprises: at least one first duct (22) for introducing/distributing air to the rotating yankee cylinder (14); and at least one second duct (24) for extracting/recovering air from the rotary yankee cylinder (14), the yankee hood (10) being characterized in that at least one of the first duct (22) for introducing/distributing air to the rotary yankee cylinder (14) and the second duct (24) for extracting/recovering air from the rotary yankee cylinder (14) is positioned outside the housing (12).

2. Yankee hood (10) according to claim 1, characterized in that both the first duct (22) for introducing/distributing air to the rotating yankee cylinder (14) and the second duct (24) for extracting/recovering air from the rotating yankee cylinder (14) are positioned outside the housing (12).

3. Yankee hood (10) according to claim 1 or 2, characterized in that said first duct (22) for introducing/distributing air to said rotary yankee cylinder (14) and/or said second duct (24) for extracting/recovering air from said rotary yankee cylinder (14) are positioned at said upper wall (18) of said housing (12).

4. Yankee hood (10) according to claim 1 or 2, characterized in that said first duct (22) for introducing/distributing air to said rotating yankee cylinder (14) and/or said second duct (24) for extracting/recovering air from said rotating yankee cylinder (14) are provided with respective external tubular surfaces, which are at least partially thermally insulated.

5. Yankee hood (10) according to claim 1 or 2, characterized in that said housing (12) is internally provided with at least one distribution partition wall hydraulically connected to said first duct (22) for introducing/distributing air, and designed to distribute air in a controlled manner through said inner wall (16) towards said rotary yankee cylinder (14).

6. Yankee hood (10) according to claim 5, characterized in that said at least one distribution partition wall is provided with one or more control gates (30), said control gates (30) being adapted to control the distribution of air to said rotating yankee cylinder (14).

7. Yankee hood (10) according to claim 1 or 2, characterized in that said housing (12) is internally provided with at least one vacuum operating chamber (32), said vacuum operating chamber (32) being hydraulically connected to said second duct (24) for extracting/recovering air, and said vacuum operating chamber (32) being designed for: -recovering air from the rotary yankee cylinder (14) through the inner wall (16), and-delivering the air recovered from the rotary yankee cylinder (14) to the second duct (24) for extracting/recovering air.

8. Yankee hood (10) according to claim 1 or 2, characterized in that said first duct (22) for introducing/distributing air to said rotating yankee cylinder (14) and/or said second duct (24) for extracting/recovering air from said rotating yankee cylinder (14) are ducts with circular cross section.

9. Yankee hood (10) according to claim 1 or 2, characterized in that said first duct (22) for introducing/distributing air to said rotary yankee cylinder (14) and/or said second duct (24) for extracting/recovering air from said rotary yankee cylinder (14) are provided with respective support frames integrally joined with at least one of said inner wall (16) and/or said upper wall (18) of said casing (12).

10. The yankee hood (10) according to claim 1 or 2, characterized in that the yankee hood (10) comprises a first yankee half and a second yankee half, wherein the second yankee half is symmetrical with respect to the first yankee half about a plane perpendicular to the side surface of the rotating yankee cylinder (14).