Coating device for enabling optical fiber to automatically pass through in optical fiber drawing process

Abstract

The invention belongs to the technical field of optical fiber manufacturing, and relates to a coating device for enabling an optical fiber to automatically pass through in an optical fiber drawing process, which comprises a coating unit for coating the optical fiber; the guiding unit is used for guiding the optical fiber to enable the optical fiber to automatically pass through the coating unit and the guiding unit in sequence; after the structure is adopted, the device has the beneficial effects that the device is safe and reliable, and the optical fiber can automatically penetrate through the coating mold only by means of compressed air.

Description

Technical Field

[0001] The invention belongs to the technical field of optical fiber manufacturing, and in particular relates to a coating device for automatically passing an optical fiber in an optical fiber drawing process. Background Art

[0002] In the optical fiber drawing process, the preform is melted in the drawing furnace, and under the action of traction, the preform is drawn into a bare optical fiber. However, since silica, the base material of the bare optical fiber, is easily brittle at room temperature, a protective layer needs to be coated on the surface of the bare optical fiber in the optical fiber drawing process to enhance the toughness of the optical fiber.

[0003] During the coating process, the optical fiber needs to pass through the entire coating mold, that is, a through hole needs to be opened on the coating mold; at the same time, the inside of the mold needs to be able to continuously supply coating to the optical fiber to complete the coating of the optical fiber surface, that is, the inner cavity of the mold needs to separate the through hole on the mold into two discontinuous mold holes; in addition, during the optical fiber coating process, a certain pressure needs to be applied to the coating so that the coating adheres to the optical fiber surface. At this time, if the size of the mold hole is too large, the coating layer will be difficult to control, and even worse, the coating will leak. Therefore, the diameter of the mold hole can only be designed to be slightly larger than the diameter of the bare optical fiber. The above reasons make it difficult for the optical fiber to pass through the coating mold.

[0004] When the optical fiber passes through the coating die, the method of actively feeding the optical fiber into the coating die is usually adopted. However, since the die hole is composed of two discontinuous parts and the size of the die hole is slightly larger than the diameter of the optical fiber, this active fiber feeding method often fails to smoothly pass the bare optical fiber through the coating die due to the poor strength of the bare optical fiber and electrostatic adsorption. Sometimes, the bare optical fiber even breaks in the coating die and blocks the die hole, which greatly affects the production efficiency.

[0005] When the bare fiber diameter is relatively thick, the problem of the bare fiber not being able to pass through the coating die is not very prominent by improving the skill level of the operator, because the fiber itself has good rigidity and the influence of electrostatic adsorption is relatively small. However, in some cases where there are requirements for the fiber diameter, due to the reduction of the bare fiber diameter, the fiber itself deteriorates in rigidity and electrostatic adsorption, it is very easy for the fiber to be unable to pass through the coating die, which has become a bottleneck problem restricting the drawing of fine-diameter optical fibers. Therefore, the development of a device that can automatically allow the optical fiber to pass through the coating die has become an urgent need that affects the development of the entire industry. Summary of the invention

[0006] In order to solve the above problems in the prior art, the present invention provides a coating device for automatically passing optical fiber during the optical fiber drawing process. The coating device is suitable for thin-diameter optical fibers with poor rigidity and severe electrostatic adsorption, and can fundamentally solve the bottleneck problem that restricts the drawing of thin-diameter optical fibers.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] As one aspect of the present invention, a coating device for automatically passing an optical fiber in an optical fiber drawing process is provided, comprising:

[0009] A coating unit, used for coating optical fibers;

[0010] A guiding unit, wherein the guiding unit guides the optical fiber so that the optical fiber automatically passes through the coating unit and the guiding unit in sequence;

[0011] The coating unit comprises a coating base, the coating base has a first installation space, a coating cup is connected in the first installation space, and a coating mold is connected to a coating outlet end of the coating cup;

[0012] The coating cup is provided with a first optical fiber passing passage, and the first optical fiber passes through the coating cup through the passage; the coating cup is provided with a coating chamber, and the coating chamber is used to fill the coating for coating the surface of the optical fiber;

[0013] The coating mold comprises a coating mold body, a second optical fiber passing channel is formed in the coating mold body, the second optical fiber passing channel penetrates the coating mold body, and the coating in the coating chamber can enter the second optical fiber passing channel;

[0014] The guide unit comprises a guide seat, a third optical fiber passing channel is arranged in the guide seat, and the third optical fiber passing channel penetrates the guide seat; the guide seat is connected to the coating mold; the guide seat is detachably connected to a pneumatic seat, and the pneumatic seat has an inner cavity, and the inner cavity surrounds part of the guide seat to form a buffer air chamber; a plurality of conducting holes are arranged at intervals on the guide seat; the buffer air chamber is connected to the third optical fiber passing channel through the plurality of conducting holes; the pneumatic seat is connected to one or more compressed air joints, and the inner end of the compressed air joint is connected to the inner cavity;

[0015] In the guide unit, a relatively closed buffer air chamber is formed between the air pressure seat and the guide seat; compressed air is injected into the buffer air chamber through the compressed air joint and discharged along the guide hole on the guide seat, forming negative pressure on the inlet end of the third optical fiber through the channel of the guide unit; since a sealed connection has been formed between the coating unit and the guide unit, the negative pressure formed at the inlet end of the guide unit expands toward the front end in turn, forming negative pressure at the inlet end of the first optical fiber through the channel of the coating unit; at this time, under the action of negative pressure, the optical fiber automatically passes through the coating cup, the coating chamber, the coating mold, and the guide seat in turn, and finally passes out from the outlet end of the third optical fiber through the channel of the guide unit, thereby realizing that the optical fiber automatically passes through the coating mold.

[0016] Optionally, a center line of the second optical fiber passing through the channel coincides with a center line of the first optical fiber passing through the channel; a center line of the third optical fiber passing through the channel coincides with a center line of the second optical fiber passing through the channel.

[0017] Optionally, a first connecting hole is provided on the coating outlet end of the coating cup, and the coating mold is connected to the first connecting hole; the coating chamber is in communication with the first connecting hole;

[0018] The outlet end of the first optical fiber passing through the channel is lower than the end face of the first connecting hole, and there is a preset gap between the outlet end of the first optical fiber passing through the channel and the coating mold. The coating mold is connected to the first connecting hole to seal the coating outlet end of the coating cup so that the coating in the coating chamber can enter the coating mold and cooperate with the optical fiber; a connecting boss is formed on the coating mold body, and when the coating mold body is connected to the coating cup, the connecting boss cooperates with the first connecting hole; the height of the connecting boss is lower than the depth of the first connecting hole; the second optical fiber passing through the channel passes through the coating mold body and the connecting boss.

[0019] Optionally, a size of an entrance end of the second optical fiber passing through the channel is larger than a size of an exit end of the second optical fiber passing through the channel.

[0020] Optionally, a fastener is further included, and the air pressure seat is detachably connected to the guide seat via the fastener.

[0021] Optionally, a mounting bracket is further included, and the coating unit and the guiding unit are respectively detachably connected to the mounting bracket.

[0022] Optionally, a heat dissipation chamber is formed in the coating base, and the heat dissipation chamber is filled with a heat dissipation medium.

[0023] Optionally, a first sealing ring is further included, wherein the first sealing ring is located between the connection between the coating mold and the coating cup.

[0024] Optionally, a second sealing ring is also included, and the second sealing ring is located at the connection between the guide seat and the coating mold.

[0025] Optionally, a third sealing ring is also included, and the third sealing ring is located between the connection between the air pressure seat and the guide seat.

[0026] The coating device for automatically passing an optical fiber in an optical fiber drawing process of the present invention has the following beneficial effects, which are specifically embodied in: 1. High degree of automation: compressed air is introduced through a compressed air joint to form a negative pressure at the inlet end of the first optical fiber passing channel of the coating unit, so that the optical fiber located at the inlet end of the first optical fiber passing channel of the coating unit is automatically sucked in under the adsorption effect of the negative pressure, and automatically passes through the coating cup, the coating chamber, the coating mold, and the guide seat in sequence under the guidance of the airflow, and finally automatically passes out from the outlet end of the third optical fiber passing channel under the guidance of the airflow;

[0027] 2. Safe and reliable: The optical fiber can automatically pass through the coating mold with the help of compressed air.

[0028] 3. Good sealing performance: By designing a sealing ring, a closed space can be formed in the coating unit, thereby using the airflow amplification principle and negative pressure adsorption technology to achieve the purpose of automatically allowing the optical fiber to pass through the coating mold. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings in the specification, which constitute a part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0030] Figure 1 It is a schematic structural diagram of a coating device for automatically passing an optical fiber through in an optical fiber drawing process according to the present invention;

[0031] Figure 2 It is a structural schematic diagram of the coating unit of the present invention;

[0032] Figure 3 It is a schematic structural diagram of the guiding unit of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0034] An embodiment of the present application is a coating device for automatically passing an optical fiber through a fiber drawing process, such as Figure 1-Figure 3 As shown, it includes:

[0035] Coating unit 1, used for coating optical fiber;

[0036] The guiding unit 2 guides the optical fiber so that the optical fiber automatically passes through the coating unit 1 and the guiding unit 2 in sequence.

[0037] Specifically, Figure 1-Figure 2 As shown, the coating unit 1 includes a coating base 11, the coating base 11 has a first installation space, a coating cup 12 is connected in the first installation space, a first connecting hole 123 is opened on the coating outlet end of the coating cup 12, and a coating mold 13 is connected to the first connecting hole 123;

[0038] A first optical fiber passage 121 is provided in the coating cup 12, and the first optical fiber passage 121 passes through the coating cup 12; a coating chamber 122 is provided in the coating cup 12, and the coating chamber 122 is used to load coating for coating the surface of the optical fiber; the coating chamber 122 is connected to the first connecting hole 123; the outlet end of the first optical fiber passage 121 is lower than the end face of the first connecting hole 123, and there is a preset gap between the outlet end of the first optical fiber passage 121 and the coating mold 13, and the coating mold 13 is connected to the first connecting hole 123 to block the coating outlet end of the coating cup 12, so that the coating in the coating chamber 122 can enter the coating mold 13 to cooperate with the optical fiber, thereby coating the surface of the optical fiber;

[0039] The coating mold 13 includes a coating mold body 131, on which a connecting boss 132 is formed. When the coating mold body 131 is connected to the coating cup 12, the connecting boss 132 cooperates with the first connecting hole 123; the height of the connecting boss 132 is lower than the depth of the first connecting hole 123; a second optical fiber passing channel 133 is formed in the coating mold body 131, and the second optical fiber passing channel 133 sequentially penetrates the coating mold body 131 and the connecting boss 132, so that the coating in the coating chamber 122 can enter the second optical fiber passing channel 133; the second optical fiber passing channel 133 3 coincides with the center line of the first optical fiber passing through the channel 121; the second optical fiber passing through the channel 133 is located directly below the first optical fiber passing through the channel 121; the optical fiber enters from the entrance end of the first optical fiber passing through the channel 121, and then passes through from the exit end of the first optical fiber passing through the channel 121 to the entrance end of the second optical fiber passing through the channel 133, and then passes through the exit end of the second optical fiber passing through the channel 133; the size of the entrance end of the second optical fiber passing through the channel 133 is larger than the size of the exit end of the second optical fiber passing through the channel 133, so that the optical fiber is extruded and coated during the threading process in the second optical fiber passing through the channel 133, and the coating effect is good.

[0040] In one embodiment, a first sealing ring 3 is further included. The first sealing ring 3 is located between the connection between the coating mold 13 and the coating cup 12, and is used to ensure that the coating in the coating chamber 122 does not leak from the connection between the coating mold 13 and the coating cup 12 during the pressure coating process. Specifically, a first mounting groove for mounting the first sealing ring 3 is connected to the end surface of the coating cup 12.

[0041] Specifically, Figure 1-Figure 3 As shown, the guide unit 2 includes a guide seat 21, a third optical fiber passing channel 22 is provided in the guide seat 21, and the third optical fiber passing channel 22 passes through the guide seat 21; the size of the third optical fiber passing channel 22 is larger than the size of the second optical fiber passing channel 133; the center line of the third optical fiber passing channel 22 coincides with the center line of the second optical fiber passing channel 133; the guide seat 21 is connected to the coating mold 13; the guide seat 21 is detachably connected to the air pressure seat 23 through a fastener 24, as an example, the fastener 24 is screwed with the guide seat 21 The air pressure seat 23 has an inner cavity 231, and the inner cavity 231 surrounds part of the guide seat 21 to form a buffer air chamber; a plurality of conducting holes 211 are arranged at intervals on the guide seat 21, and the conducting holes 211 are arranged obliquely; the buffer air chamber is connected to the third optical fiber through channel 22 through a plurality of conducting holes 211; the air pressure seat 23 is connected to one or more compressed air connectors 232, the inner end of the compressed air connector 232 is connected to the inner cavity 231, and the outer end of the compressed air connector 232 is connected to the compressed air output end.

[0042] In this embodiment, in the guide unit 2, under the action of the fastener 24, a relatively closed buffer air chamber is formed between the air pressure seat 23 and the guide seat 21; compressed air is injected into the buffer air chamber through the compressed air connector 232, and discharged along the guide hole 211 on the guide seat 21, forming a negative pressure on the inlet end of the third optical fiber of the guide unit 2 through the channel 22;

[0043] In the above process, since a sealed connection has been formed between the coating unit 1 and the guiding unit 2, the negative pressure formed at the inlet end of the guiding unit 2 expands toward the front end in sequence, so that negative pressure is formed at the inlet end of the first optical fiber passing through the channel 121 located in the coating unit 1; at this time, under the action of the negative pressure, the optical fiber automatically passes through the coating cup 12, the coating chamber 122, the coating mold 13, the guide seat 21 in sequence, and finally passes through the outlet end of the third optical fiber passing through the channel 22 of the guiding unit 2, thereby realizing that the optical fiber automatically passes through the coating mold 13.

[0044] The present application utilizes the airflow amplification principle and negative pressure adsorption technology. By adding a guiding unit 2 to the coating unit 1, compressed air is introduced through the compressed air connector 232 to form a negative pressure at the inlet end of the first optical fiber through the channel 121 of the coating unit 1, so that the optical fiber located at the inlet end of the first optical fiber through the channel 121 of the coating unit 1 is automatically sucked in under the adsorption effect of the negative pressure, and automatically passes through the coating cup 12, the coating chamber 122, the coating mold 13, and the guide seat 21 in sequence under the guidance of the airflow, and finally automatically passes out from the outlet end of the third optical fiber through the channel 22 under the guidance of the airflow; it is particularly suitable for thin-diameter optical fibers with poor rigidity and severe electrostatic adsorption, and can fundamentally solve the bottleneck problem that restricts the drawing of thin-diameter optical fibers.

[0045] In one embodiment, a mounting bracket 4 is further included, and the coating unit 1 and the guiding unit 2 are respectively detachably connected to the mounting bracket 4; the mounting bracket 4 is used to support the entire coating device.

[0046] In one embodiment, a heat dissipation chamber 111 is formed in the coating base 11, and the heat dissipation chamber 111 is filled with a heat dissipation medium, such as water; the heat dissipation chamber 111 surrounds the first installation space, and provides a preset temperature environment for the coating cup 12 located in the first installation space, ensuring that the coating in the coating chamber 122 is coated on the surface of the optical fiber while meeting the process parameters.

[0047] In one embodiment, a second sealing ring 5 is further included. The second sealing ring 5 is located between the connection between the guide seat 21 and the coating mold 13 to improve the sealing between the two. Specifically, the end of the guide seat 21 is provided with a first installation groove for installing the second sealing ring 5.

[0048] In one embodiment, a third sealing ring 6 is further included. The third sealing ring 6 is located between the connection between the air pressure seat 23 and the guide seat 21 to improve the sealing between the two. Specifically, a second installation groove for installing the third sealing ring 6 is provided at the end of the air pressure seat 23.

[0049] In summary, the coating device for automatically passing an optical fiber through an optical fiber drawing process of the present application has the following beneficial effects:

[0050] 1. High degree of automation: compressed air is introduced through the compressed air joint to form negative pressure at the inlet end of the first optical fiber through-channel of the coating unit, so that the optical fiber at the inlet end of the first optical fiber through-channel of the coating unit is automatically sucked in under the adsorption effect of the negative pressure, and automatically passes through the coating cup, the coating chamber, the coating mold, and the guide seat in sequence under the guidance of the airflow, and finally automatically passes through the outlet end of the third optical fiber through-channel under the guidance of the airflow;

[0051] 2. Safe and reliable: The optical fiber can automatically pass through the coating mold with the help of compressed air.

[0052] 3. Good sealing performance: By designing a sealing ring, a closed space can be formed in the coating unit, thereby using the airflow amplification principle and negative pressure adsorption technology to achieve the purpose of automatically allowing the optical fiber to pass through the coating mold.

[0053] 4. Obvious economic benefits: low cost, the optical fiber can automatically pass through the coating mold with the help of compressed air, fundamentally solving the problem of low success rate and low production efficiency in the process of optical fiber passing through the coating mold due to poor rigidity of the optical fiber itself and electrostatic adsorption.

[0054] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0055] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present application. Meanwhile, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0056] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0057] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" may include both "above" and "below". The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0058] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0059] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0060] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A coating device for automatically passing an optical fiber through an optical fiber drawing process, characterized in that: It includes: A coating unit, used for coating optical fibers; A guiding unit, wherein the guiding unit guides the optical fiber so that the optical fiber automatically passes through the coating unit and the guiding unit in sequence; The coating unit comprises a coating base, the coating base has a first installation space, a coating cup is connected in the first installation space, and a coating mold is connected to a coating outlet end of the coating cup; The coating cup is provided with a first optical fiber passing passage, and the first optical fiber passes through the coating cup through the passage; the coating cup is provided with a coating chamber, and the coating chamber is used to fill the coating for coating the surface of the optical fiber; The coating mold comprises a coating mold body, a second optical fiber passing channel is formed in the coating mold body, the second optical fiber passing channel penetrates the coating mold body, and the coating in the coating chamber can enter the second optical fiber passing channel; The guide unit includes a guide seat, in which a third optical fiber passing channel is provided, and the third optical fiber passing channel passes through the guide seat; the guide seat is connected to the coating mold; the guide seat is detachably connected to a pneumatic seat, and the pneumatic seat has an inner cavity, and the inner cavity surrounds part of the guide seat to form a buffer air chamber; a plurality of conducting holes are arranged at intervals on the guide seat; the buffer air chamber is connected to the third optical fiber passing channel through the plurality of conducting holes; the pneumatic seat is connected to one or more compressed air connectors, and the inner end of the compressed air connector is connected to the inner cavity.

2. The coating device for automatically passing an optical fiber in an optical fiber drawing process according to claim 1, characterized in that: The center line of the second optical fiber passing through the channel coincides with the center line of the first optical fiber passing through the channel; the center line of the third optical fiber passing through the channel coincides with the center line of the second optical fiber passing through the channel.

3. The coating device for automatically passing an optical fiber in an optical fiber drawing process according to claim 2, characterized in that: A first connecting hole is provided on the coating outlet end of the coating cup, and the coating mold is connected to the first connecting hole; the coating chamber is connected to the first connecting hole; The outlet end of the first optical fiber passing through the channel is lower than the end face of the first connecting hole, and there is a preset gap between the outlet end of the first optical fiber passing through the channel and the coating mold. The coating mold is connected to the first connecting hole to seal the coating outlet end of the coating cup so that the coating in the coating chamber can enter the coating mold and cooperate with the optical fiber; a connecting boss is formed on the coating mold body, and when the coating mold body is connected to the coating cup, the connecting boss cooperates with the first connecting hole; the height of the connecting boss is lower than the depth of the first connecting hole; the second optical fiber passing through the channel passes through the coating mold body and the connecting boss.

4. The coating device for automatically passing an optical fiber in an optical fiber drawing process according to claim 1, characterized in that: The size of the entrance end of the second optical fiber passing through the channel is larger than the size of the exit end of the second optical fiber passing through the channel.

5. The coating device for automatically passing an optical fiber in an optical fiber drawing process according to claim 1, characterized in that: It also includes a fastener, and the air pressure seat is detachably connected to the guide seat through the fastener.

6. The coating device for automatically passing an optical fiber in an optical fiber drawing process according to claim 1, characterized in that: It also includes a mounting bracket, and the coating unit and the guiding unit are respectively detachably connected to the mounting bracket.

7. The coating device for automatically passing an optical fiber in an optical fiber drawing process according to claim 1, characterized in that: A heat dissipation chamber is formed in the coating base, and a heat dissipation medium is filled in the heat dissipation chamber.

8. The coating device for automatically passing an optical fiber in an optical fiber drawing process according to claim 1, characterized in that: The coating device also includes a first sealing ring, which is located between the connection between the coating die and the coating cup.

9. The coating device for automatically passing an optical fiber in an optical fiber drawing process according to claim 1, characterized in that: The invention also comprises a second sealing ring, which is located at the connection between the guide seat and the coating mold.

10. The coating device for automatically passing an optical fiber in an optical fiber drawing process according to claim 1, characterized in that: It also includes a third sealing ring, which is located between the connection between the air pressure seat and the guide seat.

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