Sealing die of steel pipe hydrostatic testing machine
By improving the structure of the sealing mold, the inner retaining ring and the large-gap sealing ring are fitted inside the outer retaining ring. Combined with the stepped through hole and highly elastic material, the problem of high equipment cost and inconvenience in replacing small-sized steel pipes with traditional molds is solved, achieving the effect of lightweight and convenient replacement.
Patent Information
- Application Number
- CN202520613985.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-02
- Publication Date
- 2026-02-17
- Estimated Expiration
- 2035-04-02
AI Technical Summary
When replacing the sealing mold of the existing steel pipe hydrostatic testing machine with a smaller steel pipe, the design strength of the insert plate and valve body must be considered according to the minimum specification, resulting in high equipment cost and inconvenience for mold replacement.
A novel sealing mold structure is designed, in which an inner retaining ring and a large-gap sealing ring are fitted inside an outer retaining ring, and the outer retaining ring encloses the inner retaining ring and the large-gap sealing ring. Modular assembly is achieved through stepped through holes, and a highly elastic material is used to increase the number of sealing rings to improve sealing performance.
The reduced positive pressure of the insert plate enables a lightweight design, lowers equipment costs, and facilitates mold disassembly and replacement, thereby improving production efficiency.
Smart Images
Figure CN223923802U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the technical field of steel pipe hydrostatic testing devices, specifically relating to a sealing mold for a steel pipe hydrostatic testing machine. Background Technology
[0002] In steel pipe manufacturing, hydrostatic testing is a crucial quality control process, mandated by API standards. The sealing mold of the hydrostatic testing machine is a core component, directly impacting the pressure holding effect and production pace during the test. A single hydrostatic testing machine can perform hydrostatic tests on steel pipes of various specifications. When the specifications of the produced steel pipes change, the sealing mold of the hydraulic press needs to be replaced. This is especially true for seamless stainless steel pipes, which are typically produced in small batches with multiple specifications, resulting in a high frequency of mold replacements. Therefore, the sealing mold must not only provide a reliable seal but also be easily replaceable to improve production efficiency.
[0003] Figure 1 This is a schematic diagram of the end cap of a steel pipe hydrostatic testing machine. Two valve bodies 1 are respectively fitted onto the two ends of the steel pipe 3 being tested. The two valve bodies 1 are fixed-end water filling valves. Figure 1 (left) and the moving end exhaust valve body ( Figure 1 (Right) A sealing mold is installed in valve body 1. Under the pre-sealing pressure of the sealing mold, the steel pipe 3 is radially sealed. Then, water is filled and air is vented inside the steel pipe, and the pressure is increased to the required test pressure. Traditional sealing mold designs are as follows: Figure 2 As shown, the sealing mold is installed inside the valve body 1. The traditional sealing mold consists of a traditional inner retaining ring 4, a traditional large-gap sealing ring 5, a traditional outer retaining ring 6, and a slide plate 2. The slide plate 2 is installed in the T-slot of the valve body 1. The T-slot is used to withstand the axial pressure generated by the water pressure on the slide plate 2 during the water pressure test. The traditional inner retaining ring 4, traditional large-gap sealing ring 5, and traditional outer retaining ring 6 are installed in a hole with a diameter of D1 in the valve body 1. Figure 2 The sealing mold for the largest pipe diameter that the steel pipe hydrostatic testing machine can test is defined by dimension D1, which depends on the outer diameter of the largest gap sealing ring. For smaller steel pipes, the size of the large gap sealing ring decreases, requiring... Figure 3 As shown, a bushing 7 is added to the outer ring of the conventional large gap seal 5 to support the large gap seal.
[0004] This design will have the following drawbacks:
[0005] Assuming the water pressure test pressure of steel pipe 3 is P, when steel pipe 3 undergoes a water pressure test, the force-bearing area of the water pressure acting on the insert plate 2 through the retaining rings (traditional inner retaining ring 4, traditional outer retaining ring 6) is ΦD1-Φd1( Figure 2 ) or ΦD1-Φd2( Figure 3 The normal force acting on the insert plate 2 on the annular surface of the plate is:
[0006] or
[0007] Where d1 is the outer diameter of the large-diameter steel pipe and d2 is the outer diameter of the small-diameter steel pipe. It can be seen that as the diameter d of the test steel pipe decreases, the positive pressure F acting on the insert plate 2 increases accordingly, reaching its maximum value when testing the smallest specification steel pipe. The design strength of the insert plate 2 and valve body 1 must be considered based on the positive pressure when testing the smallest specification steel pipe. This results in relatively large dimensions and weight for the insert plate 2 and valve body 1, increasing equipment costs and hindering mold replacement. Utility Model Content
[0008] The present invention provides a sealing mold for a steel pipe hydrostatic testing machine. The purpose is to overcome the problem that in the prior art, the design strength of the insert plate and valve body needs to be considered according to the positive pressure when testing the smallest specification steel pipe. The size and weight of the insert plate and valve body will be relatively large, which increases the equipment cost and is not conducive to mold replacement.
[0009] Therefore, this utility model provides a sealing mold for a steel pipe hydrostatic testing machine. Two valve bodies are symmetrically arranged on the left and right. The sealing mold includes a plate, and the plate is inserted into each valve body. Both ends of the steel pipe are inserted into the valve body through the plate. The sealing mold is then fitted onto the outer sleeve of the steel pipe inserted into the valve body. The sealing mold is located between the valve body and the plate. The sealing mold also includes an inner retaining ring, a large gap sealing ring, and an outer retaining ring. The inner retaining ring, the large gap sealing ring, and the outer retaining ring are sequentially fitted onto the outside of the steel pipe, and the outer retaining ring covers the inner retaining ring and the large gap sealing ring.
[0010] Preferably, the outer retaining ring is cylindrical in shape, horizontally positioned, and has stepped through holes axially along its horizontal center.
[0011] Preferably, the stepped through hole is a three-step structure, with the outer radial direction of the three steps decreasing towards the insert plate.
[0012] Preferably, the inner retaining ring protrudes outward on the side away from the insert plate, and the protrusion of the insert plate matches and connects with the hole at the maximum outer diameter of the three-step ladder.
[0013] Preferably, the valve body has a sealing mold hole and a water passage hole sequentially opened in the direction away from the insert plate along the central axis, with the outer diameter of the sealing mold hole > the outer diameter of the inner retaining ring protrusion > the outer diameter of the water passage hole.
[0014] Preferably, the sealing mold further includes a sealing ring, with the sealing ring sleeved between the inner retaining ring and the outer retaining ring.
[0015] Preferably, the sealing mold further includes a second sealing ring, which is fitted between the outer retaining ring on the side away from the insert plate and the valve body.
[0016] Preferably, the sealing mold further includes a sealing ring three, which is sleeved between the outer side of the outer retaining ring and the valve body.
[0017] Preferably, the large-gap sealing ring is made of a highly elastic material.
[0018] The beneficial effects of this utility model are:
[0019] The sealing mold for the steel pipe hydrostatic testing machine provided by this utility model greatly reduces the positive pressure on the insert plate. Compared with the traditional solution, it reduces the design strength of the insert plate, allowing the insert plate and valve body to achieve optimal lightweight design. At the same time, since the inner retaining ring and the large gap sealing ring are installed inside the outer retaining ring, it is convenient to disassemble and assemble the mold as a whole, reducing equipment costs and facilitating mold replacement. Attached Figure Description
[0020] The present invention will be further described in detail below with reference to the accompanying drawings.
[0021] Figure 1 This is a schematic diagram of the end cap of a traditional steel pipe hydrostatic testing machine;
[0022] Figure 2 This is a schematic diagram of a traditional large-diameter pipe sealing mold.
[0023] Figure 3 This is a schematic diagram of a traditional small-diameter pipe sealing mold.
[0024] Figure 4 This is a schematic diagram of the sealing mold structure of the steel pipe hydrostatic testing machine of this utility model;
[0025] Figure 5 There are 2 Figure 4 Schematic diagram of the combined structure.
[0026] Explanation of reference numerals in the attached diagram: 1. Valve body; 2. Insert plate; 3. Steel pipe; 4. Traditional inner retaining ring; 5. Traditional large gap sealing ring; 6. Traditional outer retaining ring; 7. Liner ring; 8. Inner retaining ring; 9. Gap sealing ring; 10. Outer retaining ring; 11. Sealing ring one; 12. Sealing ring two; 13. Sealing ring three; 1.1. Sealing ring one; 1.2. Water passage hole. Detailed Implementation
[0027] The principles and features of this utility model are described below with reference to the accompanying drawings. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model.
[0028] Example 1:
[0029] like Figure 4 and Figure 5As shown, a sealing mold for a steel pipe hydrostatic testing machine has two valve bodies 1 symmetrically arranged on the left and right. The sealing mold includes a plate 2, which is inserted into each valve body 1. Both ends of a steel pipe 3 are inserted into the valve body 1 through the plate 2. The sealing mold is then fitted over the steel pipe 3 inserted into the valve body 1. The sealing mold is located between the valve body 1 and the plate 2. The sealing mold also includes an inner retaining ring 8, a large gap sealing ring 9, and an outer retaining ring 10. The inner retaining ring 8, the large gap sealing ring 9, and the outer retaining ring 10 are sequentially fitted over the outside of the steel pipe 3, and the outer retaining ring 10 covers the inner retaining ring 8 and the large gap sealing ring 9.
[0030] Specifically, when the diameter of the test steel pipe 3 decreases and the size of the large-gap sealing ring 9 decreases accordingly, the test steel pipe 3 is cancelled. Figure 3 The inner ring 7 in the middle replaces the traditional outer retaining ring 6 as follows: Figure 4 The outer retaining ring 10 shown is in the form of an inner retaining ring 8 and a large-gap sealing ring 9. In this way, when the steel pipe 3 is subjected to a water pressure test, the area of the positive pressure acting on the insert plate 2 through the inner retaining ring 8 and the outer retaining ring 10 is reduced to an annular surface of ΦD2-Φd2. The annular force-bearing surface between ΦD1-ΦD2 in the original scheme is transformed into the internal force of the outer retaining ring 10, where ΦD1 is the inner hole of the valve body 1 (outer diameter of the outer retaining ring 10), ΦD2 is the outer diameter of the large-gap sealing ring 9 used for small-sized steel pipes, and Φd2 is the outer diameter of the small-sized steel pipe. This design significantly reduces the positive pressure on the insert plate 2. Compared to traditional solutions, it lowers the design strength of the insert plate 2, allowing for optimal lightweight design of the insert plate 2 and valve body 1. Furthermore, since the inner retaining ring 8 and the large-gap sealing ring 9 are both installed within the outer retaining ring 10, it facilitates the overall disassembly and assembly of the mold. When the steel pipe hydrostatic testing machine needs to replace the mold within a certain specification range, only the inner retaining ring 8, the large-gap sealing ring 9, and the outer retaining ring 10 within the valve body 1 need to be replaced; the insert plate 2 does not need to be replaced, thus reducing equipment costs and facilitating mold replacement.
[0031] Example 2:
[0032] Based on Embodiment 1, the outer retaining ring 10 is cylindrical in shape, horizontally positioned, and has stepped through holes axially along its horizontal center.
[0033] Specifically, the cylindrical horizontal setting and the symmetrical structure of the cylinder itself make the radial force uniform, avoid stress concentration on one side, and improve the sealing performance. The stepped through hole makes full use of the space and can better seal the steel pipe 3.
[0034] Preferably, the stepped through hole is a three-step structure, with the outer radial direction of the three steps decreasing towards the side of the insert plate 2.
[0035] Specifically, the three-stage stepped through hole facilitates the installation of the inner retaining ring 8, the large-gap sealing ring 9, and the steel pipe 3 within the outer retaining ring 10, enabling modular assembly, convenient installation and disassembly, and significantly shortening maintenance time.
[0036] Preferably, the inner retaining ring 8 protrudes outward on the side away from the insert plate 2, and the protrusion of the inner retaining ring 8 matches and connects with the hole at the maximum outer diameter of the three-step ladder.
[0037] Specifically, the inner retaining ring 8 is used to axially position the outer retaining ring 10.
[0038] Preferably, the valve body 1 has a sealing mold hole 1.1 and a water passage hole 1.2 sequentially opened in the direction away from the insert plate 2 along the central axis. The outer diameter of the sealing mold hole 1.1 is greater than the outer diameter of the inner retaining ring 8 protrusion and the outer diameter of the water passage hole 1.2.
[0039] Specifically, this dimension prevents the inner retaining ring 8 from falling into the water passage hole 1.2 when the protrusion of the insert plate 2 axially positions the inner retaining ring 8.
[0040] Preferably, the sealing mold further includes a sealing ring 11, with the sealing ring 11 sleeved between the inner retaining ring 8 and the outer retaining ring 10.
[0041] Specifically, the sealing interface of the sealing ring 11 with the inner retaining ring 8 and the outer retaining ring 10, together with the large-gap sealing ring 9, forms a double-insurance structure to improve sealing performance.
[0042] Preferably, the sealing mold further includes a second sealing ring 12, which is fitted between the outer retaining ring 10 on the side away from the insert plate 2 and the valve body 1.
[0043] Specifically, sealing ring 2 12 and sealing ring 1 11 form a double seal at the front and rear, improving the sealing performance.
[0044] Preferably, the sealing mold further includes a sealing ring 3 13, which is sleeved between the outer side of the outer retaining ring 10 and the valve body 1.
[0045] Specifically, sealing ring 11 forms a radial seal to the inner retaining ring 8 and the outer retaining ring 10, sealing ring 2 12 forms an axial seal to the outer retaining ring 10 and the valve body 1, and sealing ring 3 13 forms a circumferential seal to the outer retaining ring 10 and the valve body 1. This provides all-around sealing in the radial, axial and circumferential directions, improving the sealing performance.
[0046] Preferably, the large-gap sealing ring 9 is made of a highly elastic material.
[0047] Specifically, the size of the large gap of the large gap sealing ring 9 is not specifically limited, as long as it meets the actual needs. Using a highly elastic material can better adapt to changes in the gap between the outer diameter of the steel pipe 3 and the inner wall of the outer retaining ring 10, thus improving sealing performance.
[0048] In the description of this utility model, it should be understood that if terms such as "left," "inner," or "right" indicate the orientation or positional relationship, it is based on the orientation or positional relationship shown in the drawings, and does not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are for illustrative purposes only and should not be construed as limiting this utility model.
[0049] The above examples are merely illustrative of this utility model and do not constitute a limitation on the scope of protection of this utility model. All designs that are the same as or similar to this utility model are within the scope of protection of this utility model.
Claims
1. A sealing mold for a steel pipe hydrostatic testing machine, comprising two valve bodies (1) symmetrically arranged on the left and right, the sealing mold including insert plates (2), each valve body (1) having an insert plate (2) inserted into it, both ends of a steel pipe (3) being inserted into the valve body (1) via the insert plates (2), the steel pipe (3) inserted into the valve body (1) having the sealing mold fitted over it, the sealing mold being located between the valve body (1) and the insert plates (2), characterized in that: The sealing mold also includes an inner retaining ring (8), a large gap sealing ring (9) and an outer retaining ring (10). The inner retaining ring (8), the large gap sealing ring (9) and the outer retaining ring (10) are sequentially fitted onto the outside of the steel pipe (3), and the outer retaining ring (10) covers the inner retaining ring (8) and the large gap sealing ring (9).
2. The sealing mold of the steel pipe hydrostatic testing machine as described in claim 1, characterized in that: The outer retaining ring (10) is cylindrical in shape, horizontally positioned, and has stepped through holes axially along its horizontal center.
3. The sealing mold of the steel pipe hydrostatic testing machine as described in claim 2, characterized in that: The stepped through hole is a three-step structure, with the outer radial direction of the three-step structure decreasing towards the side of the insert plate (2).
4. The sealing mold of the steel pipe hydrostatic testing machine as described in claim 3, characterized in that: The inner retaining ring (8) protrudes outward on the side away from the insert plate (2), and the protrusion of the insert plate (2) matches and connects with the hole at the maximum outer diameter of the three-step ladder.
5. The sealing mold for the steel pipe hydrostatic testing machine as described in claim 4, characterized in that: The valve body (1) has a sealing mold hole (1.1) and a water passage hole (1.2) sequentially opened in the direction away from the insert plate (2) from the center axis. The outer diameter of the sealing mold hole (1.1) is greater than the outer diameter of the inner retaining ring (8) protrusion and the outer diameter of the water passage hole (1.2).
6. The sealing mold of the steel pipe hydrostatic testing machine as described in claim 1, characterized in that: The sealing mold also includes a sealing ring (11), and the sealing ring (11) is sleeved between the inner retaining ring (8) and the outer retaining ring (10).
7. The sealing mold for the steel pipe hydrostatic testing machine as described in claim 1, characterized in that: The sealing mold also includes a second sealing ring (12), and the second sealing ring (12) is sleeved between the outer retaining ring (10) away from the insert plate (2) and the valve body (1).
8. The sealing mold of the steel pipe hydrostatic testing machine as described in claim 1, characterized in that: The sealing mold also includes a sealing ring three (13), and the sealing ring three (13) is sleeved between the outer side of the outer retaining ring (10) and the valve body (1).
9. The sealing mold for the steel pipe hydrostatic testing machine as described in claim 1, characterized in that: The large gap sealing ring (9) is made of a highly elastic material.