sealing device

Abstract

A sealing device 100 for a shaft, comprising at least a first seal element 10a arranged around a shaft 30 and at least a second seal element 10b arranged around the shaft 30, wherein the first seal element 10a and the second seal element 10b comprise adjustable seal elements, the first seal element 10a and the second seal element 10b respectively comprising an outer shell 14a, 14b of an elastic material and a hollow core 12a, 12b, wherein the hollow core 12a, 12b of the first seal element 10a and / or the second seal element 10b is pressurized with a fluid for an adjustable sealing effect.

Description

Technical Field

[0001] The present invention relates to a sealing arrangement. In particular, although not exclusively, the present invention relates to a sealing arrangement for sealing an axle or a shaft. In particular, although not exclusively, the present invention relates to a sealing arrangement for sealing an axle or a shaft of a white liquor filter or a lime filter.

Background Art

[0002] Environments involving alkaline liquids or liquid suspensions containing solid residues such as particles pose high demands on any sealing arrangement for both technical and safety reasons. Conventionally, braided seal ropes have been used.

[0003] In such environments, any alkaline liquid such as white liquor easily penetrates conventional sealing arrangements compared to, for example, water, so the sealing arrangement must provide effective sealing. Furthermore, suspensions containing solid residues can cause the seal to harden and begin to wear both the seal and the sealing surface.

[0004] Furthermore, in general, to seal an axle or a shaft of, for example, a rotary filter in a white liquor plant that rotates, reciprocates axially, and is exposed to pressures and temperatures that vary according to process conditions, a seal that can adapt to the conditions and follow the sealing surface is required for effective sealing in all situations. Previously, in addition to seal ropes, braided seals with elastic cores have been used.

[0005] The inventors have found that existing solutions do not always provide efficient sealing in all situations. Accordingly, a sealing arrangement having an adjustable seal element for efficient sealing is provided that uses a pressurized seal element whose pressure is monitored and adjusted.

Summary of the Invention

[0006] The objective of the present invention is to improve existing solutions by providing an efficient sealing device that uses an adjustable sealing element. [Means for solving the problem]

[0007] Various embodiments of the present invention are described in the claims.

[0008] According to a first exemplary embodiment of the present invention, a sealing device for a shaft, At least a first sealing element positioned around the shaft, At least a second sealing element positioned around the shaft and Equipped with, The first sealing element and the second sealing element are equipped with adjustable sealing elements. The first sealing element and the second sealing element each comprise an elastic outer shell and a hollow core, The hollow cores of the first and / or second sealing elements are pressurized with a fluid for an adjustable sealing effect. A sealing device for the shaft is provided.

[0009] The outer shell may have an outer layer of braided material.

[0010] At least the first sealing element and / or the second sealing element may include an electrical circuit element configured to break due to wear or tear of its outer shell.

[0011] The sealing device may further include valves connected to inlets for supplying fluid to pressurize the first sealing element and the second sealing element, respectively.

[0012] Fluids can include gases such as air.

[0013] The sealing device may further include a fluid space between at least a first sealing element and a second sealing element.

[0014] The pressure in a fluid space may be adjustable.

[0015] The shaft may include the shaft of the rotary filter unit.

[0016] According to a second exemplary embodiment of the present invention, Setting a first pressure inside the first sealing element arranged around the shaft, Setting a second pressure inside a second sealing element positioned around the shaft, Monitoring the pressure inside the first seal element and / or the second seal element, Adjusting the internal pressure of the first sealing element and / or the second sealing element for an adjustable sealing effect. A method for controlling a sealing device for a shaft, according to a first exemplary embodiment of the present invention, is provided, including the following.

[0017] The method may further include monitoring wear of the first sealing element and / or the second sealing element using an electrical circuit element.

[0018] The method may further include scheduling the replacement of the first or second sealing element based on monitoring pressure and / or wear.

[0019] According to a third exemplary aspect of the present invention, a rotary filter unit is provided comprising a sealing device according to the first exemplary aspect of the present invention.

[0020] According to a fourth exemplary aspect of the present invention, a control system is provided for controlling a sealing device of the first exemplary aspect of the present invention, comprising a control device connected to at least one measuring and actuator module for performing the method of the second exemplary aspect of the present invention.

[0021] According to a fifth exemplary aspect of the present invention, there is provided a computer program including computer-executable program code that, when executed by a processor, causes the method according to the second exemplary aspect to be executed.

[0022] According to a sixth exemplary aspect of the present invention, there is provided a non-transitory memory medium including the computer program of the fifth exemplary aspect.

[0023] Various non-limiting exemplary aspects and examples of the present invention have been shown above. The above examples are merely used to illustrate selected aspects or steps that can be utilized in the implementation of the present invention. Some examples may be presented only with respect to some exemplary aspects of the present invention. It should be understood that the corresponding examples may also be applicable to other exemplary aspects.

[0024] For a more complete understanding of the exemplary embodiments of the present invention, reference is now made to the following description taken in conjunction with the accompanying drawings.

Brief Description of the Drawings

[0025] [Figure 1] A diagram showing a schematic cross-sectional view of a sealing device according to an exemplary embodiment of the present invention. [Figure 2] A diagram showing a further schematic cross-sectional view of a sealing device according to an exemplary embodiment of the present invention. [Figure 3] A diagram showing a schematic perspective view of a sealing device according to an exemplary embodiment of the present invention. [Figure 4] A diagram showing a schematic cross-sectional view of a seal element according to an exemplary embodiment of the present invention. [Figure 5] A diagram showing a schematic block diagram of a sealing device control system according to an exemplary embodiment of the present invention. [[ID=�5]] [Figure 6] A diagram showing a flowchart of a sealing device control method according to an exemplary embodiment of the present invention.

Modes for Carrying Out the Invention

[0026] Figure 1 shows a schematic cross-sectional view of a sealing device 100 according to an exemplary embodiment of the present invention. The sealing device 100 is shown around the shaft 30 at the end of the shaft 30 of a disc filter unit. In one embodiment, the filter unit is a rotary filter unit of a white liquor plant, such as a white liquor filter or a lime mud filter. The sealing device 100 comprises at least a first or outer sealing element 10a and at least a second or inner sealing element 10b. The first sealing element 10a and the second sealing element 10b are arranged concentrically around the shaft 30. In one embodiment, the device comprises at least one further sealing element (not shown). The device 100 comprises a fluid space 60 between the first sealing element 10a and the second sealing element 10b. The fluid space 60 is filled with a fluid, in one embodiment water, to enhance the sealing effect and to flush the sealing surface while preventing solid particles from abrading the sealing elements. In one embodiment, the fluid pressure in the fluid space 60 is controlled or regulated to a suitable pressure, for example, by adjusting the fluid flow into the fluid space 60. In one embodiment, the fluid pressure in the fluid space 60 is greater than the pressure inside the rotary filter.

[0027] The shaft 30 rotates around its axis as indicated by the arrow in Figure 1. The direction of rotation is not definitive. Furthermore, the shaft 30 reciprocates axially as indicated by the arrow in Figure 1. The combined rotation and reciprocation impose high demands on the sealing device 100. With conventional sealing, the sealing element would have to be subjected to a large pressing force, causing significant friction. Moreover, especially in the case of a hollow shaft, as in one embodiment used in a rotary filter unit, the seal may be compromised if the shaft 30 is not perfectly circular, as manufacturing a perfectly circular shaft is costly and difficult. Furthermore, it should be noted that the inside of the filter unit is pressurized and contains alkaline substances, which make the operating environment harsh.

[0028] Therefore, the first seal element 10a and the second seal element 10b are adjustable, meaning the sealing effect is controlled by pressurizing the seal elements 10a and 10b through pressure valves 16a and 16b using a pressurized fluid, or in one embodiment, a gas such as air. The internal pressures of the first seal element 10a and the second seal element 10b are individually adjustable, meaning the pressurization does not need to be at the same level for both. In one embodiment, the internal pressures of the first pressure element 10a and / or the second pressure element 10b are set to correspond to the ambient pressure. The adjustable pressure contributes to an adjustable sealing effect, meaning the pressures of the first seal element 10a and the second seal element 10b are adjusted to provide a sealing effect in each operating condition. In one embodiment, the pressure in the fluid space 60 is adjusted relative to the pressures of the first seal element 10a and the second seal element 10b. In one embodiment, the pressure in the fluid space 60 is lower than the pressure in the first seal element 10a and the second seal element 10b. In one embodiment, the fluid to the fluid space 60 is supplied via a hydraulic accumulator to ensure the sealing effect of the fluid in the event of an interruption in the fluid supply. Figure 1 further shows the arrangement of the first seal element 10a and the second seal element 10b. In one embodiment, the first seal element 10a is positioned between the outer shell 20 of the filter unit and the gland 40. In one embodiment, the second seal element 10b is positioned between the gland 40 of the filter unit and the interior. The first seal element 10a and the second seal element 10b are shown to have the same size, i.e., diameter and inner cross-sectional diameter, but in further embodiments, the first seal element 10a and the second seal element 10b may have different sizes. In one exemplary embodiment, the diameter of the first seal element 10a and the diameter of the second seal element 10b, i.e., the shaft diameter, are 1300 mm.

[0029] Figure 2 further shows a schematic cross-sectional view of a sealing device according to an exemplary embodiment of the present invention, enlarged relative to Figure 1. Figure 2 shows a first sealing element 10a and a second sealing element 10b. In an exemplary embodiment, the sealing element comprises an ExSeal sealing element. Each sealing element 10, 10b comprises an outer shell 14a, 14b and a hollow core 12a, 12b. In one embodiment, the outer shells 14a, 14b include an elastic material. In one embodiment, the outer shells 14a, 14b comprise a layer of an elastic material such as rubber and an outer layer that is wear-resistant and tear-resistant, such as an outer layer of braided material.

[0030] The hollow cores 12a, 12b of the first seal element 10a and the second seal element 10b are pressurized with a fluid, a gas such as air in one exemplary embodiment. The fluid is introduced into the interior of the first seal element 10a and the second seal element 10b through nipples or valves 18a, 18b, respectively. The valves 18a, 18b are connected through the outer shell of the filter unit to inlets 16a, 16b, respectively, for supplying the fluid to pressurize the seal elements 10a, 10b.

[0031] In one embodiment, as shown in Figures 1 and 2, the valves 18a, 18b and inlets 16a, 16b are arranged perpendicular to the axis of the shaft around which the sealing elements are placed. In a further embodiment shown in Figure 3, the valves 18a, 18b and inlets 16a, 16b are arranged parallel to the axis of the shaft around which the sealing elements are placed. In yet another embodiment, the arrangement of the valves 18a, 18b and inlets 16a, 16b differs with respect to the first sealing element 10a and the second sealing element 10b.

[0032] Figure 3 shows a schematic three-dimensional view of a sealing device according to an exemplary embodiment of the present invention. Figure 3 shows a first sealing element 10a and a second sealing element 10b around a shaft 30. Figure 3 also shows the joints 15a, 15b between the first sealing element 10a and the second sealing element 10b. In one embodiment, the sealing elements 10a and 10b are formed into rings from tubes that are closed at both ends, rather than being continuous rings, and are attached at their ends at the joints 15a, 15b. Figure 3 further shows the inlets 16a, 16b of the first sealing element 10a and the second sealing element 10b, respectively. In the embodiment of Figure 3, the tube of the inlet 16b of the second sealing element 10b is located in the joint 15a of the first sealing element 10a.

[0033] Figure 4 shows a schematic cross-sectional view of a sealing element according to an exemplary embodiment of the present invention. Figure 4 shows a first sealing element 10a as an example, and those skilled in the art will understand that the structure and function of a second sealing element 10b and further sealing elements are similar in one embodiment. The first sealing element comprises a hollow core 12a, an elastic outer shell 14a, and a valve 18a attached to an inlet 16a for supplying pressurized fluid, as previously described with respect to Figures 1 to 3. In the embodiment of Figure 4, the sealing element 10a further comprises at least one electrical circuit element 50a configured to conduct electric current until it breaks. In one embodiment, the electrical circuit element 50a comprises, for example, a copper wire. The electrical circuit element 50a is located in the outer shell 14a of the sealing element 10 such that, when the sealing element 10a is subjected to wear, the outer shell wears down or tears during use, causing the electrical circuit element 50a to break at some point. If the electrical circuit element 50a is disconnected, the electrical circuit element 50a will no longer conduct a detectable current, and thus excessive wear of the sealing element 10a will be detected. In a further embodiment, the sealing element 10a further comprises a temperature sensor embedded therein.

[0034] Figure 5 shows a schematic block diagram of a sealing device control system according to an exemplary embodiment of the present invention. Figure 5 shows a sealing device 100 and control means connected thereto. The control system comprises a control device 500. In one embodiment, the control device 500 is a standalone control device, such as a local control device or a cloud-based control system, configured to control the sealing device 100. In a further embodiment, the control device 500 is integrated into a mill-wide control system.

[0035] The control device 500 is connected to the measuring and actuator modules 510a and 510b. In one embodiment, a separate measuring and actuator module is provided for each seal element 10a, 10b. In a further embodiment, a single measuring and actuator module is provided jointly for all seal elements 10, 10b. The measuring and actuator modules 510a and 510b are configured to measure the pressure inside the first seal element 10a and the second seal element 10b of the sealing device 100. Furthermore, the measuring and actuator modules 510a and 510b are configured to operate means for supplying and regulating the pressure inside the first seal element 10a and the second seal element 10b, such as valves. In a further embodiment, the measuring and actuator modules 510a and 510b are configured to monitor the current conducted by the electrical circuit element 50a in order to detect wear that has caused an electrical circuit to break. In further embodiments, the measurement and actuator modules 510a and 510b are configured to monitor the temperature of the sealing elements 10a and 10b.

[0036] Figure 6 shows a flowchart of a sealing device control method according to an exemplary embodiment of the present invention. In one embodiment, the method according to an exemplary embodiment of the present invention is performed by a processor, for example, the processor of a control system or control device 500. In step 610, the pressure inside at least the first seal element 10a and / or the second seal element 10b and the pressure in the fluid space 60 are set. In one embodiment, the pressure is set to a predetermined pressure value. In a further embodiment, the pressure is set according to the operating pressure of the filter unit in the current operating conditions. In one embodiment, the pressure is set to different values ​​for the first seal element 10a and the second seal element 10b. In one embodiment, the pressure inside at least the first seal element 10a and the second seal element 10b is substantially in the range of 0.5 to 4 bar, preferably 1.6 to 3 bar.

[0037] In step 620, the pressure inside the first seal element 10a and / or the second seal element 10b is monitored during operation. In one embodiment, the pressure is monitored in real time or intermittently. In one embodiment, the pressure is monitored using a pressure sensor. In a further embodiment, the pressure is monitored by monitoring the amount of fluid, such as air, required to maintain the pressure. If the pressure, or the amount of fluid required to maintain the pressure, decreases, the seal elements 10a and 10b may be excessively worn, in which case replacement of the seal elements will be scheduled in step 640. In one embodiment, the pressure inside the first seal element 10a and / or the second seal element 10b is adjusted in step 610, also during operation, for example, based on the operating conditions or based on the measurement in step 620.

[0038] In one embodiment, wear of the first sealing element 10a and / or the second sealing element 10b is monitored using an electrical circuit element 50a. In one embodiment, the wear monitor includes an alarm that is triggered when the electrical circuit element 50a is not conducting, i.e., when the circuit is broken due to wear of the sealing element. In such a case, the sealing element is scheduled to be replaced in step 640.

[0039] Without limiting in any way the scope, interpretation, or application of the claims described herein, one or more technical effects of the exemplary embodiments disclosed herein is to provide an effective seal for rotating and reciprocating shafts. Another technical effect of one or more of the exemplary embodiments disclosed herein is to provide an effective seal in an alkaline environment. Another technical effect of one or more of the exemplary embodiments disclosed herein is to enable adjustment and monitoring of the seal efficiency. Yet another technical effect of one or more of the exemplary embodiments disclosed herein is a safer, more maintenance-free seal. Another technical effect of one or more of the exemplary embodiments disclosed herein is an improved seal lifespan.

[0040] Where necessary, the different functions described herein may be performed in different orders and / or simultaneously with each other. Furthermore, where necessary, one or more of the previously described functions may be performed at will or in combination.

[0041] While various aspects of the present invention are described in the independent claims, other aspects of the present invention include other combinations of features from the described examples and / or dependent claims and features from the independent claims, and are not limited to the combinations expressly described in the claims.

[0042] Furthermore, while the above description in this specification provides exemplary embodiments of the present invention, it should be noted that these descriptions should not be considered restrictive. Rather, there are several variations and modifications that can be made without departing from the scope of the present invention as defined in the appended claims.

Claims

1. A sealing device (100) for a shaft, At least, a first sealing element (10a) is arranged around the shaft (30), At least a second sealing element (10b) arranged around the shaft (30) and Equipped with, The first sealing element (10a) and the second sealing element (10b) are equipped with adjustable sealing elements. The first sealing element (10a) and the second sealing element (10b) each comprise an elastic outer shell (14a, 14b) and a hollow core (12a, 12b), The hollow cores (12a, 12b) of the first sealing element (10a) and / or the second sealing element (10b) are pressurized with a fluid for an adjustable sealing effect. At least the first sealing element (10a) and / or the second sealing element (10b) comprises an electrical circuit element (50a) configured such that the outer shell (14a, 14b) wears down or tears, causing a break in the circuit. A sealing device (100) for a shaft, characterized by the above.

2. The sealing device according to claim 1, wherein the outer shell (14a, 14b) comprises an outer layer of braided material.

3. The sealing device according to claim 1 or 2, further comprising valves (18a, 18b) connected to inlets (16a, 16b) for supplying the fluid to pressurize the first sealing element (10a) and the second sealing element (10b), respectively.

4. The sealing device according to claim 1 or 2, wherein the fluid includes a gas.

5. The sealing device according to claim 1 or 2, further comprising a fluid space (60) between at least the first sealing element (10a) and the second sealing element (10b).

6. The sealing device according to claim 5, wherein the pressure in the fluid space (60) is adjustable.

7. The sealing device according to claim 1 or 2, wherein the shaft (30) includes the shaft of a rotary filter unit.

8. Setting a first pressure inside the first sealing element (10a) arranged around the shaft (30), Setting a second pressure inside the second sealing element (10b) arranged around the shaft (30), Monitoring the pressure inside the first sealing element (10a) and / or the second sealing element (10b), Adjusting the pressure inside the first sealing element (10a) and / or the second sealing element (10b) for an adjustable sealing effect, The wear of the first sealing element (10a) and / or the second sealing element (10b) is monitored using the electrical circuit element (50a). A method for controlling a sealing device (100) for a shaft according to claim 1 or 2, characterized by the above.

9. The method according to claim 8, further comprising scheduling the replacement of the first seal element (10a) or the second seal element (10b) based on monitoring the pressure and / or the wear.

10. A rotary filter unit comprising the sealing device described in claim 1 or 2.

11. A control system comprising a control device (500) connected to at least one measuring and actuator module (510a, 510b), wherein the method of claim 8 is performed to control the sealing device according to claim 1 or 2. A control system characterized by the following features.

12. A computer program product comprising computer-readable program code that, when executed by a processor, causes to perform the method described in claim 8.

13. A non-temporary memory medium comprising the computer program product described in claim 12.

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