Sealing ring for unbonded steel strand

Abstract

The invention relates to a sealing ring for an unbonded steel strand. An elastic sealing ring body, a C-shaped sealing face protruding inwards, a lip, an end face and the like of the sealing ring form sealing structural elements. The cross section of the elastic sealing ring body is of a C-shaped structure protruding towards the inner side, an annular groove is formed in the outer side of the sealing ring body, the elastic sealing ring body is divided into lip portions at the two ends and an arc-shaped sealing face portion in the middle, and an end face portion is arranged between the lip portions and the arc-shaped sealing face portion. The sealing ring not only can be used for sealing the surface of a cylinder, but also is particularly suitable for sealing many irregular cylinder-like surfaces. For example, the shape of the outer contour of the sealed unbonded steel strand HDPE sheath is close to that of a hexagonal spiral prism with an arc angle instead of a cylindrical surface, so that the sealing element is required to have a good shape follow-up fitting effect, and the requirement is well met.

Description

Technical Field

[0001] The present invention relates to the technical field of prestressed engineering sealing, and in particular to a sealing ring for unbonded steel strands, which is particularly suitable for sealing and protecting external prestressed anchors, anchor cables and unbonded steel strand stay cables in projects such as bridges and prestressed concrete wind power towers. Background Art

[0002] Currently, among the products such as external prestressed anchors, anchor cables and unbonded steel strand cables used in engineering fields such as bridges and prestressed concrete wind turbines, the main sealing components for unbonded steel strands are the following, such as porous rubber sheets, rectangular cross-section sealing rings, or sealing rings, dust rings and sealants in the hydraulic and pneumatic fields. The above sealing components are more suitable for sealing circular structures.

[0003] like Figure 3 As shown, the unbonded steel strand consists of a steel strand body 201 formed by twisting a plurality of high-strength steel wires, anti-corrosion grease on the outside of the steel strand body, and a protective jacket 202 tightly wrapped in the outer layer of the anti-corrosion grease. The outer contour of the sealed unbonded steel strand protective jacket is close to a hexagonal spiral prism with rounded corners, rather than a cylindrical surface (the steel strand shown in the figure is not the content of the invention, and this figure is provided mainly to help explain the principles and ideas of the invention). Because the above-mentioned sealing element is more suitable for sealing products with circular sealing surfaces, it is limited by the principle of the sealing structure. The current sealing element has certain problems with the sealing reliability and durability of the unbonded steel strand. The use of the above-mentioned sealing structure often manifests itself in stress corrosion of the steel strand due to the failure of the sealing structure, which leads to premature replacement of the steel strand or anchor cable, thereby resulting in large economic losses.

[0004] The present invention aims to solve the existing problems, and through the study of engineering characteristics and engineering needs, the characteristics of the sealed steel strands, and the in-depth study of the sealing principle, the sealing ring is specially invented. Summary of the Invention

[0005] The purpose of the present invention is to provide a sealing ring for unbonded steel stranded wire, which is adaptable to the cylindrical irregular outer contour of the unbonded steel stranded wire sheath and the wide range of outer diameter sizes of the unbonded steel stranded wire sheath. Therefore, the sealing ring has good sealing effect, strong versatility, simple structure, is conducive to promotion, has high cost performance and is easy to maintain.

[0006] The technical solution of the present invention:

[0007] A sealing ring for unbonded steel strands comprises an elastic sealing ring body, the cross section of which is a C-shaped structure convex inward, an annular groove is provided on the outside of the sealing ring body, and the elastic sealing ring body is divided into lip portions at both ends and an arc-shaped sealing surface portion in the middle, with an end face portion between the lip portion and the arc-shaped sealing surface portion.

[0008] Beneficial effects of the present invention:

[0009] 1. The sealing ring of the present invention is not only suitable for sealing cylindrical surfaces, but is also particularly suitable for sealing many irregular cylindrical-like surfaces. For example, the outer contour of the HDPE sheath of the unbonded steel strand being sealed is closer to a hexagonal spiral prism with rounded corners than a cylindrical surface, requiring the sealing element to have excellent conformability. The present invention satisfies this requirement.

[0010] 2. The outer contour dimensions of the sealed HDPE sheath of the unbonded steel strand in the prior art are not fixed. Taking unbonded steel strands with diameters of Φ15.2 and Φ15.7 as examples, if the tolerances of the steel strand diameter, the sheath wall thickness, and the different grease contents are taken into account, the outer contour dimensions of the unbonded steel strand sheaths of the above specifications can range from Φ17.2 to Φ20.5 in actual engineering. This size range is relatively large, approaching 19.2%. It is difficult to meet such a wide range of sealing versatility requirements using commonly used sealing elements in the prior art. The present invention solves this problem, making it easier to promote its industrial application. In other words, the seal of the present invention has excellent versatility and practicality.

[0011] 3. In the sealing structure of the anchor and the steel strand of the present application, the inner side of the sealing ring is sealed with the outer protective cover of the unbonded steel strand, the outer side is sealed with the anchor plate, and the upper and lower sides are sealed with the anchor plate and the pressure plate respectively. This structural design makes the sealing effect of the anchor and the unbonded steel strand better. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0013] Figure 1 This is a schematic diagram of the sealing ring structure for the unbonded steel stranded wire used in this application.

[0014] Figure 2 This is a schematic diagram of the sealing structure of the anchor and steel strand in this application.

[0015] Figure 3 Schematic diagram of the unbonded steel strand structure.

[0016] Reference numerals:

[0017] Figure 1 Middle: elastic sealing ring body 1;

[0018] The sealing ring structural elements include: lip 101; arc-shaped sealing surface 102; end surface 103; annular groove 104;

[0019] Figure 2 Middle: sealing ring 1; unbonded steel strand 2; anchor plate 3; pressure plate 4; screw 5;

[0020] The conical anchor hole 301 on the anchor plate; the arc-shaped sealing surface 102 of the sealing ring;

[0021] Unbonded steel strand sheath outer contour surface 203; Unbonded steel strand sheath end surface 204;

[0022] Figure 3 Middle: Steel strand 201; Unbonded steel strand sheath 202. DETAILED DESCRIPTION

[0023] To address the issues raised in the background art, the present invention discloses a sealing ring for unbonded steel strands. This ring is primarily used to seal unbonded steel strands. Its primary application areas include external prestressed anchors, anchor cables, and unbonded steel strand stay cables used in projects such as bridges and prestressed concrete wind turbines. This ring prevents moisture from entering the anchor and prevents grease and oil from escaping.

[0024] It should be noted that, in the description of this application, terms such as "inside", "outside", "upper", and "lower" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on this application.

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0026] A sealing ring for unbonded steel strands comprises an elastic sealing ring body 1 having an inwardly convex C-shaped cross-section. The outer surface of the sealing ring body 1 has an annular groove 104, which is divided into two lip portions 101 at each end and a central arcuate sealing surface 102. An end surface 103 is located between the lip portions 101 and the arcuate sealing surface 102. The angle between the two end surfaces 103 of the elastic sealing ring body 1 is β, with 0°≤β≤45°. The elastic sealing ring body 1 is made of rubber. The elastic sealing ring body is an annular structure, with the inwardly convex C-shaped sealing surface, lip portion, and end surface forming a sealing structure. The inwardly convex arcuate sealing surface contacts the HDPE sheath of the unbonded steel strand, sealing the unbonded steel strand. The end surface and lip portion each form a separate sealing structure that contacts the sealing elements of the anchor plate and pressure plate of the anchor, thereby forming a complete sealing structure. The presence of an annular groove on the outer side of the sealing ring allows for significant compression of the sealing ring, enabling the sealing ring of the present invention to better adapt to the outer contour characteristics of the HDPE sheath of the unbonded steel strand and also to accommodate fluctuations in the outer contour dimensions of the HDPE sheath. This also facilitates the promotion of industrial applications and broadens the scope of applicability. The strand body of the unbonded steel strand passes through the sealing ring, where the outer contour surface 203 of the protective sheath contacts and seals against the arcuate sealing surface 102 of the sealing ring.

[0027] The sealing structure of the present application, which is a combination of a sealing ring, an anchor and an unbonded steel strand, includes an anchor, an unbonded steel strand 2 and a sealing ring 1. The anchor includes an anchor plate 3 and a pressure plate 4. The anchor plate and the pressure plate are connected by screws 5. The sealing ring is the sealing ring 1 mentioned above. The anchor plate 3 is provided with an anchor hole 301 for the steel strand to pass through. The anchor plate 3 is provided with a sealing groove at one end thereof close to the pressure plate 4. The sealing ring 1 is placed in the sealing groove. The sealing ring 1 is pressed by the anchor plate 3 and the pressure plate 4 so that the upper and lower end faces 103 of the sealing ring are in tight sealing contact with the anchor plate 3 and the pressure plate 4 respectively. The steel strand 2 passes through the anchor hole 301, and the inner side of the sealing ring 1 is in tight contact with the outer contour surface 203 of the protective jacket of the unbonded steel strand 2 to achieve sealing. The lip 101 on the outside of the sealing ring 1 is in tight sealing contact with the sealing groove.

[0028] The sealing ring operates within the anchor plate: The ring is positioned within the sealing groove, and the pressure plate compresses the ring. The lip and end face seal against the anchor plate and pressure plate. The ring's C-shaped curved surface closely conforms to the outer contour of the strand's PE sheath, sealing the unbonded strand. The varying outer diameters of the unbonded strand's PE sheath result in varying degrees of compression within the groove. In contrast, the compression limit for conventional rubber bodies without annular grooves is limited. This serves as a key measure to accommodate variations in sheath outer diameter. The same principle can be applied to sealing unbonded strands of other diameters.

[0029] Specific embodiment of sealing ring for unbonded steel strand:

[0030] Example 1:

[0031] Sealing ring technical parameters: sealing ring outer diameter Φ26mm, inner diameter Φ16.9mm, sealing ring height 9mm, angle between the two end faces β=45°.

[0032] Applicable unbonded steel strand size: used for sealing Φ15.2~15.7 unbonded steel strand.

[0033] Installation steps: After the anchor is assembled, push the knotless steel strand into the anchor hole, and the steel strand body is inserted into the anchor hole. The PE sheath of the knotless steel strand will radially expand the sealing ring in the sealing groove outward and make close contact with the sealing ring. The outer side and upper and lower sides of the sealing ring are in close contact with the anchor plate and the pressure plate at the same time.

[0034] Example 2:

[0035] Sealing ring technical parameters: sealing ring outer diameter Φ22mm, inner diameter Φ14.4mm, sealing ring height 8mm, angle between the two end faces β=37°.

[0036] Applicable unbonded steel strand size: used for sealing Φ12.7 unbonded steel strand.

[0037] Installation steps: After the anchor is assembled, push the knotless steel strand into the anchor hole, and the steel strand body is inserted into the anchor hole. The PE sheath of the knotless steel strand will radially expand the sealing ring in the sealing groove outward and make close contact with the sealing ring. The outer side and upper and lower sides of the sealing ring are in close contact with the anchor plate and the pressure plate at the same time.

[0038] Example 3:

[0039] Technical parameters of the sealing ring: outer diameter of the sealing ring is Φ26mm, inner diameter is Φ16.8mm, height of the sealing ring is 8mm, and the angle between the two end faces β=0°, that is, the two end faces of the sealing ring are parallel.

[0040] Applicable unbonded steel strand size: used for sealing Φ15.2~15.7 unbonded steel strand.

[0041] Installation steps: After the anchor is assembled, push the knotless steel strand into the anchor hole, and the steel strand body is inserted into the anchor hole. The PE sheath of the knotless steel strand will radially expand the sealing ring in the sealing groove outward and make close contact with the sealing ring. The outer side and upper and lower sides of the sealing ring are in close contact with the anchor plate and the pressure plate at the same time.

[0042] The above is a schematic description of the present invention and its embodiments, which is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by the above and does not deviate from the technical solution of the present invention, and designs a structure and implementation similar to the above embodiment without inventiveness based on the technical essence of the present invention, such design shall fall within the scope of protection of the present invention.

Claims

1. A sealing ring for unbonded steel strand, characterized in that: It includes an elastic sealing ring body, the cross section of which is a C-shaped structure bulging inward, and an annular groove on the outside of the sealing ring body. The elastic sealing ring body is divided into lip parts at both ends and an arc-shaped sealing surface part in the middle, and the end face part is between the lip part and the arc-shaped sealing surface part.

2. The sealing ring for unbonded steel strand according to claim 1, characterized in that: The included angle between the two end faces of the elastic sealing ring body is β, 0°≤β≤45°.

3. The sealing ring for unbonded steel strand according to claim 1, characterized in that: The elastic sealing ring body is made of rubber material.

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