Paper machine press section vacuum system

Abstract

The application relates to a paper machine press section vacuum system. The paper machine press section vacuum system comprises a first vacuum pump, a first vacuum suction point, a second vacuum pump, a second vacuum suction point and a vacuum pipeline. The vacuum pipeline comprises a first pipeline connecting the first vacuum pump with the first vacuum suction point, a second pipeline connecting the second vacuum pump with the second vacuum suction point and a communication pipeline connecting the first vacuum pump with the second vacuum suction point and connecting the second vacuum pump with the first vacuum suction point. The communication pipeline is provided with a first valve for connecting or disconnecting the first vacuum pump with the second vacuum suction point and a second valve for connecting or disconnecting the second vacuum pump with the first vacuum suction point. The paper machine press section vacuum system further comprises a third valve and a fourth valve. The third valve is arranged on the second pipeline and is used for connecting or disconnecting the second vacuum pump with the second vacuum suction point. The fourth valve is used for opening or closing the outlet pipe of the second vacuum pump.

Description

Technical Field

[0001] This utility model relates to a vacuum system for the press section of a papermaking machine. Background Technology

[0002] The papermaking process (including vacuum suction, pressing, and drying) requires the removal of a significant amount of water, particularly in the forming wire and press sections. The felts in both the forming wire and press sections have pores that facilitate dewatering, and vacuum is used to enhance dewatering efficiency. The pulp forms a wet paper web in the forming wire section and then enters the press section for further dewatering. The press section is equipped with press rolls forming a pressing zone, the surfaces of which are covered with felts. As the wet paper web passes through the pressing zone, the water in the paper web is removed through the felts and by vacuum suction. The vacuum system in the press section is crucial for water removal. Part of the vacuum acts directly on the felts, drawing away the water from the paper web through the felts.

[0003] The press section is a crucial area in the papermaking process for further improving paper dryness. In this area, a series of press rolls, blankets, and vacuum chambers effectively remove moisture from the paper. However, in conventional press section vacuum systems, the energy consumption of this vacuum component remains high and cannot be adjusted according to the operating characteristics of the blankets. Utility Model Content

[0004] The purpose of this invention is to provide a vacuum system for the press section of a paper machine that can reduce energy consumption.

[0005] This utility model provides a vacuum system for the press section of a paper machine, including a first vacuum pump, a first vacuum suction point, a second vacuum pump, a second vacuum suction point, and a vacuum pipeline. The vacuum pipeline has: a first pipeline connecting the first vacuum pump to the first vacuum suction point; a second pipeline connecting the second vacuum pump to the second vacuum suction point; and a connecting pipeline connecting the first vacuum pump to the second vacuum suction point and the second vacuum pump to the first vacuum suction point. The connecting pipeline is provided with a first valve for connecting or disconnecting the first vacuum pump and the second vacuum suction point, and a second valve for connecting or disconnecting the second vacuum pump and the first vacuum suction point. The vacuum system for the press section of the paper machine further includes a third valve and a fourth valve. The third valve is disposed in the second pipeline for connecting or disconnecting the second vacuum pump and the second vacuum suction point, and the fourth valve is used to open or close the outlet pipe of the second vacuum pump.

[0006] According to the vacuum system of the press section of the paper machine of this invention, the second vacuum pump can be stopped easily, thereby reducing energy consumption.

[0007] In the vacuum system of the press section of the paper machine described above, the first and second valves can also be manual valves, while the third and fourth valves can be automatic valves (e.g., solenoid valves). This allows the second vacuum pump to be quickly isolated by closing the third and fourth valves, avoiding time loss and suppressing or preventing large vacuum fluctuations in the vacuum pipeline.

[0008] In the vacuum system of the press section of the paper machine described above, the connecting pipe may also include: a main pipe; a first connecting pipe connecting the first pipe to the main pipe; and a second connecting pipe connecting the second pipe to the main pipe, with a first valve disposed on the first connecting pipe and a second valve disposed on the second connecting pipe. Thus, a cooperative mode can be switched between the first valve and the second valve.

[0009] In the aforementioned vacuum system of the paper machine press section, the connecting pipe may also further include: a third connecting pipe connecting the main pipe to the first vacuum pump, the third connecting pipe being equipped with a fifth valve for opening or closing the third connecting pipe; and a fourth connecting pipe connecting the main pipe to the second vacuum pump, the fourth connecting pipe being equipped with a sixth valve for opening or closing the fourth connecting pipe. Thus, for example, in the event of a failure of one vacuum pump, vacuum pumping can be performed on the first and second vacuum suction points using the other vacuum pump.

[0010] In the vacuum system of the press section of the paper machine described above, the connecting pipe may be connected to the first vacuum suction point via a first pipe, and the connecting pipe may be connected to the second vacuum suction point via a second pipe at a position closer to the second vacuum suction point than the third valve.

[0011] In the vacuum system of the press section of the paper machine described above, the connecting pipe may also include: a main pipe; a first connecting pipe, the first connecting pipe connecting the first pipe to the main pipe; and a second connecting pipe, the second connecting pipe connecting the second pipe to the main pipe, and connecting to the second vacuum suction point via the second pipe at a position closer to the second vacuum suction point than the third valve.

[0012] In the vacuum system of the press section of the paper machine described above, there may be two or more second vacuum suction points, and the second connecting pipe is connected to the second pipe between the branching part of the second pipe to the two or more second vacuum suction points and the third valve.

[0013] In the vacuum system of the press section of the paper machine described above, it may also include a first suction section and a second suction section. The first suction section includes: a first press blanket that contacts the paper web and is used to remove moisture from the paper web; a first vacuum suction box that removes moisture from the first press blanket; a second press blanket that contacts the paper web and is used to remove moisture from the paper web; and a second vacuum suction box that removes moisture from the second press blanket. The second suction section includes: a third press blanket that contacts the paper web and is used to remove moisture from the paper web; and a third vacuum suction box that removes moisture from the third press blanket. The first vacuum suction box serves as the first vacuum suction point, and the second and third vacuum suction boxes serve as the second vacuum suction point.

[0014] Preferably, the first vacuum pump and the second vacuum pump are turbine vacuum pumps. This further reduces energy consumption. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the paper machine press section using a vacuum system of the paper machine press section according to an embodiment of the present invention.

[0016] Figure 2 This is a block diagram schematically illustrating the structure of a vacuum system in the press section of a paper machine according to an embodiment of the present invention.

[0017] Figure 3 This is a block diagram schematically illustrating the structure of a portion of the vacuum system of the press section of a paper machine according to an embodiment of the present invention.

[0018] Symbol Explanation

[0019] 1 First vacuum pump; 2 Second vacuum pump; 3 First vacuum suction box; 4 Second vacuum suction box; 5 Third vacuum suction box; 7 Connecting pipe; 10 Vacuum system of the paper machine press section; 61 First pipe; 62 Second pipe; 71 Main pipe; 72 First connecting pipe; 73 Second connecting pipe; 74 Third connecting pipe; 75 Fourth connecting pipe; 100 Press section; 101 First press blanket; 102 Second press blanket; 103 Third press blanket; a First valve; b Second valve; c Third valve; d Fourth valve; e Fifth valve; f Sixth valve Detailed Implementation

[0020] Hereinafter, with reference to the accompanying drawings, the technical solutions of the embodiments and modifications of this utility model will be described. Furthermore, the scope of this utility model is not limited to the following embodiments and modifications, and can be arbitrarily changed within the scope of the technical concept of this utility model.

[0021] Unless otherwise defined, the technical or scientific terms used in the claims and description shall have the ordinary meaning understood by one of ordinary skill in the art to which this utility model pertains. The terms "first," "second," and similar words used in this utility model patent application description and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" indicate that the elements or objects preceding "comprising" encompass the elements or objects listed following "comprising" or "including" and their equivalents, and do not exclude other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, nor are they limited to direct or indirect connections.

[0022] <First Implementation>

[0023] Figure 1 This is a schematic diagram of the structure of the paper machine press section 100 of the vacuum system 10 of the paper machine press section according to the first embodiment of the present invention. Figure 2 This is a block diagram schematically illustrating the structure of the vacuum system 10 in the press section of a paper machine according to the first embodiment. For simplicity, Figure 1 and Figure 2 Some component illustrations have been omitted. Figure 3 This is a block diagram schematically showing the structure of a portion of the vacuum system 10 in the press section of a paper machine.

[0024] The inventors have developed a vacuum system for the press section of a paper machine, which uses, for example, two vacuum pumps to remove moisture from different felts. Figure 2 As shown, in this structure, the pipeline design enables the connection of a vacuum pipe connecting a vacuum pump 1 and a vacuum suction point 3 corresponding to the vacuum pump to a vacuum pipe connecting another vacuum pump 2 and a vacuum suction point 4, 5 corresponding to the other vacuum pump. This allows the two vacuum pumps 1 and 2 to work together to handle the vacuum suction at the vacuum suction point 3 corresponding to the vacuum pump and the vacuum suction point 4, 5 corresponding to the other vacuum pump.

[0025] Through research, the inventors discovered that the air permeability of the blanket in the press section is relatively high when it is first used, requiring a higher vacuum suction volume to achieve normal dehydration. After a period of time (e.g., 3-5 days) after the machine is started, the air permeability of the blanket decreases significantly, thus reducing the required vacuum suction volume. Based on this, the vacuum system of the paper machine's press section was improved, resulting in this invention.

[0026] The vacuum system 10 (hereinafter, sometimes simply referred to as "vacuum system 10") of the paper machine press section in this embodiment can be applied to the press section 100 of a paper machine. The press section 100 is provided with a pressing zone composed of multiple press rolls, and the surface of the press rolls is covered with a blanket. In this embodiment, the press section 100 is provided with multiple press blankets 101, 102, and 103. Each press blanket is tensioned by multiple rolls to form a pressing zone. When the wet paper web passes through the pressing zone, the moisture in the paper web is removed by the blankets and vacuum suction.

[0027] In this embodiment, the vacuum system 10 includes a first suction section and a second suction section. The first suction section includes: a first press blanket 101 in contact with the paper web for removing moisture from the paper web; a first vacuum suction box 3 for removing moisture from the first press blanket 101; a second press blanket 102 in contact with the paper web for removing moisture from the paper web; and a second vacuum suction box 4 for removing moisture from the second press blanket. The second suction section includes: a third press blanket 103 in contact with the paper web for removing moisture from the paper web; and a third vacuum suction box 5 for removing moisture from the third press blanket 103. The wet paper web passes successively between the first press blanket 101 and the second press blanket 102, and between the third press blanket 103 and the belt 104. The first vacuum suction box 3 serves as the first vacuum suction point described below. The second vacuum suction box 4 and the third vacuum suction box 5 serve as the second vacuum suction points described below. The negative pressure of the vacuum suction box can be adjusted by the speed of the vacuum pump and the vacuum regulating valve at each vacuum suction point.

[0028] The vacuum system 10 of the paper machine press section includes a first vacuum pump 1, a first vacuum suction point, a second vacuum pump 2, a second vacuum suction point, and vacuum piping. The first vacuum pump 1 and the second vacuum pump 2 perform vacuum suction at the first and second vacuum suction points via the vacuum piping. The first vacuum pump 1 and the second vacuum pump 2 are, for example, turbine vacuum pumps, which helps reduce energy consumption. Alternatively, the first vacuum pump 1 and the second vacuum pump 2 can also be water ring vacuum pumps, etc. Furthermore, the first vacuum pump 1 and the second vacuum pump 2 can each be equipped with inlet and outlet manual valves (e.g., figure-eight blind flanges).

[0029] The vacuum pipeline includes: a first pipeline 61 connecting a first vacuum pump 1 to a first vacuum suction box 3 serving as a first vacuum suction point; a second pipeline 62 connecting a second vacuum pump 2 to a second vacuum suction box 4 and a third vacuum suction box 5 serving as second vacuum suction points; and a connecting pipeline 7 connecting the first vacuum pump 1 to the second vacuum suction box 4 and the third vacuum suction box 5 (second vacuum suction points), and connecting the second vacuum pump 2 to the first vacuum suction box 3 (first vacuum suction point). The second pipeline 62 includes a branching section on its upstream side (near the vacuum suction point side), thereby connecting to the second vacuum suction box 4 and the third vacuum suction box 5 respectively.

[0030] In this embodiment, the connecting pipe 7 includes: a main pipe 71; a first connecting pipe 72 connecting the first pipe 61 to the main pipe 71; a second connecting pipe 73 connecting the second pipe 62 to the main pipe 71; a third connecting pipe 74 connecting the main pipe 71 to the first vacuum pump 1; and a fourth connecting pipe 75 connecting the main pipe 71 to the second vacuum pump 2. The connecting pipe 7 is connected to the first vacuum suction box 3 via the first pipe 61. The connecting pipe 7 is connected to the second vacuum suction box 4 and the third vacuum suction box 5 via the second pipe 62.

[0031] Furthermore, the connecting pipe is equipped with a first valve a for connecting or disconnecting the first vacuum pump 1 with the second vacuum suction box 4 and the third vacuum suction box 5, and a second valve b for connecting or disconnecting the second vacuum pump 2 with the first vacuum suction box 3. More specifically, the first valve a is located in the first connecting pipe 72, and the second valve b is located in the second connecting pipe 73. The first valve a and the second valve b can be, for example, manual valves.

[0032] Vacuum system 10 also includes a third valve c and a fourth valve d. The third valve c is located in the second pipeline 62 and is used to connect or disconnect the second vacuum pump 2 from the second vacuum suction box 4 and the third vacuum suction box 5 (isolating the vacuum pipeline). The fourth valve d is used to open or close the outlet pipe of the second vacuum pump 2 (isolating the outlet). The third valve c and the fourth valve d are preferably automatic valves, such as solenoid valves. When the third valve c and the fourth valve d are automatic valves, the second vacuum pump 2 can be quickly isolated by closing the third valve c and the fourth valve d, avoiding time loss and suppressing or preventing large vacuum fluctuations in the vacuum pipeline. For example, when a new blanket is started, the third valve c and the fourth valve d are opened, and the second vacuum pump 2 starts normally (responsible for the vacuum of the second vacuum suction box 4 and the third vacuum suction box 5).

[0033] As mentioned above, after a period of time following the installation, the air permeability of the blankets will decrease, and the required vacuum suction flow rate will decrease to achieve the same vacuum level. In this case, when both vacuum pumps 1 and 2 are running, their suction flow rate will be greater than the actual required suction flow rate. Therefore, it is necessary to break a portion of the vacuum (suction volume) to maintain the minimum suction volume of vacuum pumps 1 and 2 and prevent them from surging and stopping, resulting in wasted energy and high energy consumption.

[0034] According to the vacuum system 10 of the press section of the paper machine of this utility model, for example, by studying and calculating the total amount of air suction required at each time point during the life cycle of multiple blankets corresponding to the first vacuum suction point and the second vacuum suction point to reach the expected vacuum degree (vacuum degree of the vacuum suction box corresponding to the blanket), one vacuum pump can be flexibly stopped without causing other losses, and only one vacuum pump can be used to provide all the vacuum required by the above-mentioned multiple blankets, thereby achieving energy saving effect.

[0035] For example, without the third valve c and the fourth valve d, vacuum pumps 1 and 2 must run when the paper machine is in operation. If you want to stop the other vacuum pump 2, you need to shut down the machine for at least several hours to close the manual valves at the inlet and outlet of the vacuum pump.

[0036] According to this invention, by setting a third valve c (automatic valve) and a fourth valve d (automatic valve), the third valve c and the fourth valve d can be closed during normal operation of the paper machine to isolate the second vacuum pump 2, thereby stopping the second vacuum pump 2 and achieving energy saving. For example, based on changes in air permeability, when the air permeability of the felt decreases to a level where the first vacuum pump can achieve the required suction volume after a period of operation, the second vacuum pump can be isolated through the third valve c and the fourth valve d to achieve energy saving. Here, "changes in air permeability" can be obtained by measuring the changes in air permeability during the felt's lifespan. After the second vacuum pump 2 stops, the vacuum of the first vacuum suction box 3, the second vacuum suction box 4, and the third vacuum suction box 5 is handled by the first vacuum pump 1 (the vacuum of the first vacuum suction box 3 is also handled by the first vacuum pump 1 when a new felt is started).

[0037] Furthermore, the connecting pipe 7 is connected to the second vacuum suction point via the second pipe 62 at a position closer to the second vacuum suction point than the third valve c. In this embodiment, the connecting pipe 7 is connected to the second vacuum suction point via the second pipe 62 at a position closer to the second vacuum suction point than the third valve c. The second connecting pipe 73 is connected between the branching portion of the second pipe 62 to the second vacuum suction box 4 and the third vacuum suction box 5 and the third valve c.

[0038] Furthermore, in this embodiment, the third connecting pipe 74 is provided with a fifth valve e, which is used to open or close the third connecting pipe 74, and the fourth connecting pipe 75 is provided with a sixth valve f, which is used to open or close the fourth connecting pipe 75. The fifth valve e and the sixth valve f can be, for example, manual valves.

[0039] The fifth valve e and the sixth valve f can be used to switch valves in case one of the vacuum pumps 1 or 2 fails. For example, if the second vacuum pump 2 fails, the fifth valve e, the first valve a, and the second valve b are fully open, and the sixth valve f is closed. Conversely, if the first vacuum pump 1 fails, the sixth valve f, the first valve a, and the second valve b are fully open, and the fifth valve e is closed.

[0040] In addition, the vacuum system 10 may include other components such as a gas-liquid separator 11, a vacuum regulating valve g, a drain pump 12, and a pressure relief valve h between the vacuum pump and the vacuum suction point. Figure 3 The example shows the structure corresponding to the first vacuum pump 1, but this structure can also be used for the second vacuum pump 2. The function of the gas-water separator 11 is to separate the vacuum and water. The drain pump 12 below is used to remove the water from the gas-water separator. The pressure relief valve h is used to open when the vacuum pump surges, preventing the turbine vacuum pump from tripping due to surge.

[0041] Furthermore, the vacuum system 10 of the paper machine press section in this embodiment can achieve the following operating states: by switching the opening degrees of the first valve a, the second valve b, the fifth valve e, and the sixth valve f, a mutual assistance mode of the two vacuum pumps 1 and 2 can be realized. During normal operation, the first valve a, the second valve b, the fifth valve e, and the sixth valve f can be fully open or fully closed, allowing the vacuum pipelines of vacuum pumps 1 and 2 to be connected or used independently. For example, when the first valve a, the second valve b, the fifth valve e, and the sixth valve f are fully open, vacuum pumps 1 and 2 can jointly handle the vacuum suction at the first and second vacuum suction points; when the first valve a, the second valve b, the fifth valve e, and the sixth valve f are fully closed, vacuum pumps 1 and 2 handle the vacuum suction at the first and second vacuum suction points respectively.

[0042] Furthermore, in the above embodiments, there are two second vacuum suction points, but it is not limited to this; there may be one or more than three. There may also be two or more first vacuum suction points.

[0043] Furthermore, the above embodiments describe a vacuum system for the press section of a paper machine that includes two vacuum pumps, but it is not limited to this. It may also include three or more N vacuum pumps, which are connected by a connecting pipe. A third valve c and a fourth valve d may be installed on one to N-1 of the vacuum pumps.

[0044] The specific embodiments of this utility model have been described above. However, those skilled in the art will understand that the above specific embodiments do not constitute a limitation on this utility model. Those skilled in the art can make various modifications based on the above disclosure without exceeding the scope of this utility model.

Claims

1. A vacuum system for the press section of a paper machine, characterized in that, Includes a first vacuum pump, a first vacuum suction point, a second vacuum pump, a second vacuum suction point, and vacuum piping. The vacuum pipeline comprises: a first pipeline connecting a first vacuum pump to a first vacuum suction point; a second pipeline connecting a second vacuum pump to a second vacuum suction point; and a connecting pipeline connecting the first vacuum pump to the second vacuum suction point and vice versa. The connecting pipe is equipped with a first valve for connecting or disconnecting the first vacuum pump and the second vacuum suction point, and a second valve for connecting or disconnecting the second vacuum pump and the first vacuum suction point. The vacuum system of the paper machine press section also includes a third valve and a fourth valve. The third valve is located in the second pipeline and is used to connect or disconnect the second vacuum pump from the second vacuum suction point. The fourth valve is used to open or close the outlet pipe of the second vacuum pump.

2. The vacuum system of the press section of a paper machine according to claim 1, characterized in that, Both the first valve and the second valve are manual valves. The third valve and the fourth valve are automatic valves.

3. The vacuum system for the press section of a paper machine according to claim 2, characterized in that, The automatic valve is a solenoid valve.

4. The vacuum system for the press section of a paper machine according to claim 1, characterized in that, The connecting conduit includes: a main pipe; a first connecting pipe connecting the first pipe to the main pipe; and a second connecting pipe connecting the second pipe to the main pipe. The first valve is disposed in the first connecting pipe, and the second valve is disposed in the second connecting pipe.

5. The vacuum system for the press section of a paper machine according to claim 4, characterized in that, The connecting pipe further includes: a third connecting pipe that connects the main pipe to the first vacuum pump, the third connecting pipe being provided with a fifth valve for opening or closing the third connecting pipe; and a fourth connecting pipe that connects the main pipe to the second vacuum pump, the fourth connecting pipe being provided with a sixth valve for opening or closing the fourth connecting pipe.

6. The vacuum system for the press section of a paper machine according to claim 1, characterized in that, The connecting pipe is connected to the first vacuum suction point via the first pipe. The connecting pipe is connected to the second vacuum suction point via a second pipe at a position closer to the second vacuum suction point than the third valve.

7. The vacuum system for the press section of a paper machine according to claim 6, characterized in that, The connecting pipe includes: a main pipe; a first connecting pipe that connects the first pipe to the main pipe; and a second connecting pipe that connects the second pipe to the main pipe and is connected to the second vacuum suction point via the second pipe at a position closer to the second vacuum suction point than the third valve.

8. The vacuum system for the press section of a paper machine according to claim 7, characterized in that, There are two or more second vacuum suction points, and the second connecting pipe is connected to the third valve at the branching part of the second pipeline to the two or more second vacuum suction points.

9. The vacuum system for the press section of a paper machine according to claim 1, characterized in that, Includes a first suction section and a second suction section. The first suction section includes: a first press blanket that contacts the paper web and is used to remove moisture from the paper web; a first vacuum suction box that removes moisture from the first press blanket; a second press blanket that contacts the paper web and is used to remove moisture from the paper web; and a second vacuum suction box that removes moisture from the second press blanket. The second suction section includes: a third press blanket that contacts the paper web and removes moisture from the paper web; and a third vacuum suction box that removes moisture from the third press blanket. The first vacuum suction box serves as the first vacuum suction point, and the second and third vacuum suction boxes serve as the second vacuum suction points.

10. The vacuum system for the press section of a paper machine according to claim 1, characterized in that, The first vacuum pump and the second vacuum pump are turbine vacuum pumps.

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