Stainless steel expansion bolt for underwater operation and sealing installation method thereof

Abstract

The invention relates to the technical field of ocean engineering, and provides a stainless steel expansion bolt for underwater operation, which comprises a bolt, the outer wall of the bolt is divided into three parts, the two sides of the bolt are provided with the same threads, one side of the middle part is provided with opposite threads, and the turn ratio of the opposite threads to the threads on the two sides is 2: 1; and the two sides of the limiting ring are connected with suppression blocks through limiting assemblies, the outer walls of the suppression blocks are obliquely arranged towards the outer side, the middles of the inner walls of the suppression blocks are in threaded connection with one side of the bolt, and the suppression block on one side is rotationally connected with the end of the bolt. By adopting the duplex stainless steel main body and the titanium nitride coating, the chloride ion corrosion resistance is remarkably improved; an anti-aging agent in the chemical agent can restrain ultraviolet rays and damp-heat degradation, in a double-sealing system, the chemical agent is combined with water absorption expansion, base material gaps are effectively filled, a dense curing layer is formed, the anchoring strength is larger than or equal to 800 MPa, and the sealing pressure is larger than or equal to 1.5 times of the working water pressure.

Description

Technical Field

[0001] The present invention relates to the technical field of ocean engineering, and particularly to a stainless steel expansion bolt for underwater operations and its sealing installation method. Background Technique

[0002] As a key component for ocean engineering, submarine facility installation, and underwater structure repair, underwater expansion bolts need to provide stable anchoring and sealing in high-pressure, high-humidity, and high-salt corrosion environments. Traditional bolts mostly use ordinary stainless steel or coated metals and achieve fixation through mechanical expansion or chemical bonding. However, their performance is limited by the corrosion resistance of materials, the design of the sealing structure, and the compatibility of chemical agents, and it is difficult to meet the long-term reliability requirements of deep-sea operations.

[0003] Currently, underwater expansion bolts are prone to pitting corrosion or stress corrosion cracking after long-term immersion. The sealing structure is single, relying on static sealing rings or adhesives, and cannot adapt to dynamic water pressure fluctuations, resulting in leakage risks. The chemical anchoring agents used have a slow curing speed, a low expansion rate, are difficult to fill microcracks in the base material, have poor aging resistance, and the installation process is complex, with inaccurate torque control, which is likely to cause uneven anchoring layers or bolt loosening. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention provides a stainless steel expansion bolt for underwater operations and its sealing installation method. By optimizing the bolt structure, using corrosion-resistant alloys, developing chemical agents with a high expansion rate, and combining a staged installation process, it aims to solve the core problems such as anchoring failure, insufficient sealing, and short lifespan in the prior art.

[0005] To achieve the above objectives, the present invention is realized through the following technical solutions: A stainless steel expansion bolt for underwater operations, comprising: A bolt, the outer wall of the bolt is provided with three parts, with the same thread settings on both sides, and the middle part on one side is provided with a reverse thread, and the ratio of the number of thread turns to that on both sides is 2:1; A limit ring, both sides of the limit ring are connected with pressure suppression blocks through limit components, and the outer wall of the pressure suppression block is inclined outward. The middle part of the inner wall of the pressure suppression block is threadedly connected to one side of the bolt. One pressure suppression block is rotationally connected to the end of the bolt, and the other pressure suppression block is threadedly connected to the middle side of the bolt, so as to achieve the displacement of the two pressure suppression blocks in a 2:1 relationship; A thin film capsule, the inside of the thin film capsule is filled with a chemical agent, which is used to cement and fix the bolt and the pressure suppression block in the drill hole to form a composite part for anchoring the fixed part.

[0006] Preferably, the thin film capsule is fixedly connected to the outer wall of the limit ring and is also fixedly connected to the outer wall of the pressure suppression block.

[0007] Preferably, the limiting component includes a plug inserted and slidable inside the slot. The slot is formed on the side wall of the limiting ring. The outer end of the plug is fixedly connected to the side wall of the pressing block to limit the rotation of the pressing block.

[0008] Preferably, the other side of the bolt is threadedly connected to the mounting hole, and the mounting hole is formed on one side of the mounting cap. A gasket is provided on one side of the mounting cap to achieve sealing after installation. A positioning ring is sleeved on the other side of the bolt to play a positioning role.

[0009] Preferably, holes are formed on the outer wall of the pressing block to enable the chemical agent to extend to both sides of the drill hole to achieve the effect of installation sealing.

[0010] Preferably, the chemical agent is composed of the following components by mass percentage: Epoxy resin matrix: 50% - 70%; Superabsorbent resin: 10% - 20%; Curing agent: 15% - 25%; Anti-aging agent: 2% - 5%; Silane coupling agent: 1% - 3%; Among them, the volume expansion rate of the superabsorbent resin after water absorption is 300% - 500%, which is used to fill the microcracks between the anchor bolt and the base material and form a dense cured layer in cooperation with the epoxy resin; the anti-aging agent is uniformly dispersed in the matrix to inhibit the degradation of the resin under ultraviolet and humid environments.

[0011] Preferably, the silane coupling agent is γ-aminopropyltriethoxysilane (KH550) or γ-glycidoxypropyltrimethoxysilane (KH560), which is used to enhance the bonding strength between the chemical agent and the interfaces of the anchor bolt and the base material and form a hydrophobic barrier.

[0012] Preferably, the superabsorbent resin is selected from sodium polyacrylate or starch-grafted acrylate, and the particle size is 50 - 150 μm. The mixing viscosity with the epoxy resin is controlled at 500 - 1500 mPa·s to ensure the injection glue fluidity and expansion uniformity.

[0013] A sealing installation method for a stainless steel expansion bolt for underwater operation includes the following steps: Step 1: Drill a hole in the base material and use high-pressure water jet to clean the debris and biological attachments in the hole; Step 2: Fix the thin film capsule filled with the chemical agent on the outer wall of the limiting ring of the bolt and insert the bolt into the drill hole; Step 3: Drive the pressing blocks on both sides to expand inward at a displacement ratio of 2:1 by rotating the bolt, squeeze the thin film capsule until it breaks, and release the chemical agent into the gap between the drill hole and the bolt; Step 4: The chemical agent absorbs water and expands and solidifies to form a dense anchoring layer, and at the same time, it fits tightly with the inner wall of the drill hole through the inclined outer wall of the pressure suppression block; Step 5: Install a gasket and an installation cap on the bolt head, apply a preset torque to complete the sealing, and verify the sealing performance through air pressure testing or ultrasonic testing.

[0014] Preferably, in Step 3, the curing time of the chemical agent is 20 - 40 minutes, the curing temperature range is 5 - 40 °C, and the bolt needs to be kept stationary during the curing process to avoid displacement of the anchoring layer.

[0015] The present invention provides a stainless steel expansion bolt for underwater operations and its sealing installation method. It has the following beneficial effects: 1. By adopting a duplex stainless steel main body and a titanium nitride coating, the present invention significantly improves the anti - chloride corrosion ability; the anti - aging agent in the chemical agent can inhibit ultraviolet and humidity degradation, and in the double - seal system, combined with the water - absorption expansion of the chemical agent, it effectively fills the gaps in the base material and forms a dense solidified layer, with an anchoring strength ≥ 800 MPa and a sealing pressure ≥ 1.5 times the working water pressure.

[0016] 2. The present invention adopts a split - type expansion sleeve and a pressure suppression block with a displacement ratio of 2:1 design to ensure uniform expansion; the curing time of the chemical agent is controllable and suitable for water temperatures of 5 - 40 °C; combined with IP68 waterproof tools for staged screwing, the torque accuracy is ±3%, avoiding displacement of the anchoring layer, supporting underwater operations at depths of up to 500 meters, and verifying the sealing performance through both air pressure testing and ultrasonic testing, suitable for complex marine environments. Description of the Drawings

[0017] Figure 1 It is a schematic internal structure diagram of the limit ring in the present invention; Figure 2 It is a schematic internal structure diagram of the drill hole in the present invention; Figure 3 It is for the present invention Figure 2 An enlarged view of part A in the present invention.

[0018] Among them, 1. Underwater equipment; 2. Film bladder; 3. Positioning block; 4. Bolt; 5. Installation hole; 6. Installation cap; 7. Gasket; 8. Positioning ring; 9. Limit ring; 10. Pressure suppression block; 11. Drill hole; 12. Insert rod; 13. Slot. Specific Embodiments

[0019] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0020] Embodiment: As one aspect of the present invention, please refer to the attached Figure 1 - attached Figure 3 , the present invention provides a stainless steel expansion bolt for underwater operation, including: The outer wall of the bolt 4 is provided with three parts. The two sides are provided with the same threads, and the middle part on one side is provided with reverse threads, and the ratio of the number of thread turns to the two sides is 2:1. The other side of the bolt 4 is threadedly connected to the mounting hole 5, and the mounting hole 5 is opened on one side of the mounting cap 6. A gasket 7 is provided on one side of the mounting cap 6. The gasket 7 and the mounting cap 6 are installed on the head of the bolt 4, and a preset torque is applied to complete the sealing, and the sealing performance is verified by air pressure test or ultrasonic detection to achieve the sealing performance after installation. A positioning ring 8 is sleeved on the other side of the bolt 4 for positioning. By rotating the bolt 4, the two side pressing blocks 10 are driven to expand inwards at a displacement ratio of 2:1, squeezing the film bladder 2 until it ruptures, and releasing the chemical agent into the gap between the drill hole 11 and the bolt 4; The side wall of the limiting ring 9 is provided with a slot 13, and a plug rod 12 that slides inside the slot 13. The outer end of the plug rod 12 is fixedly connected to the side wall of the pressing block 10 to limit the rotation of the pressing block 10, and the outer wall of the pressing block 10 is inclined outwards. The middle part of the inner wall of the pressing block 10 is threadedly connected to one side of the bolt 4. One side pressing block 10 is rotatably connected to the end of the bolt 4, and the other side pressing block 10 is threadedly connected to the middle side of the bolt 4 to realize the displacement of the two side pressing blocks 10 in a 2:1 relationship. The outer wall of the pressing block 10 is provided with holes to realize the extension of the chemical agent to both sides of the drill hole 11 to achieve the effect of installation sealing; The inside of the film bladder 2 is filled with a chemical agent to cement and fix the bolt 4 and the pressing block 10 in the drill hole 11 to realize a composite part for anchoring the fixing part. The film bladder 2 is fixedly connected to the outer wall of the limiting ring 9 and is also fixedly connected to the outer wall of the pressing block 10. The chemical agent absorbs water and expands and solidifies to form a dense anchoring layer, and at the same time, the inclined outer wall of the pressing block 10 is closely attached to the inner wall of the drill hole 11.

[0021] As another aspect of the present invention, the chemical agent in the above-mentioned stainless steel expansion bolt for underwater operation is composed of the following mass percentage components: Epoxy resin matrix: 50% - 70%; Superabsorbent resin: 10% - 20%; Curing agent: 15% - 25%; Anti-aging agent: 2% - 5%; Silane coupling agent: 1% - 3%; Among them, the volume expansion rate of the superabsorbent resin after water absorption is 300% - 500%, which is used to fill the microcracks between the anchor bolt and the base material and cooperate with the epoxy resin to form a dense cured layer; the anti-aging agent is evenly dispersed in the matrix to inhibit the degradation of the resin under ultraviolet rays and humid and hot environments; The silane coupling agent is γ-aminopropyltriethoxysilane KH550 or γ-glycidoxypropyltrimethoxysilane KH560, which is used to enhance the bonding strength between the chemical agent and the interfaces of the anchor bolt and the base material and form a hydrophobic barrier.

[0022] The superabsorbent resin is selected from sodium polyacrylate or starch-grafted acrylate, and the particle size is 50 - 150 μm, and the mixing viscosity with the epoxy resin is controlled at 500 - 1500 mPa·s to ensure the injection glue fluidity and expansion uniformity.

[0023] A sealing installation method for an underwater operation stainless steel expansion bolt includes the following steps: Step 1: Drill a hole 11 in the base material and use a high-pressure water jet to clean the debris and biological attachments in the hole; Step 2: Fix the thin film capsule 2 filled with the chemical agent on the outer wall of the limiting ring 9 of the bolt 4, and insert the bolt 4 into the drilled hole 11; Step 3: Drive the two-sided pressure suppression blocks 10 to expand inwards at a displacement ratio of 2:1 by rotating the bolt 4, squeeze the thin film capsule 2 until it ruptures, and release the chemical agent into the gap between the drilled hole 11 and the bolt 4. The curing time of the chemical agent is 20 - 40 minutes, the curing temperature range is 5 - 40 °C, and the bolt 4 needs to be kept stationary during the curing process to avoid the displacement of the anchoring layer; Step 4: The chemical agent absorbs water and expands and cures to form a dense anchoring layer, and at the same time, the inclined outer wall of the pressure suppression block 10 is closely attached to the inner wall of the drilled hole 11; Step 5: Install a gasket 7 and a mounting cap 6 on the head of the bolt 4, apply a preset torque to complete the sealing, and verify the sealing performance through air pressure testing or ultrasonic testing.

[0024] The chemical agent formula in an embodiment: Composition: Epoxy resin matrix (E-44 type, epoxy value 0.44): 60%; Sodium polyacrylate (SAP, particle size 80 ± 10 μm, water absorption rate ≥ 500 g / g): 15%; Polyamide curing agent (HY-650, amine value 240 mg KOH / g): 20%; Anti-aging agent (hindered amine light stabilizer 944): 3%; Silane coupling agent (KH560, purity ≥ 98%): 2%.

[0025] Preparation: Preheat the epoxy resin to 40°C, add the silane coupling agent and stir for 10 minutes (rotation speed 300 r / min); sequentially add SAP, curing agent, and anti-aging agent, and perform vacuum degassing (-0.08 MPa, 15 minutes); final viscosity: 800 ± 50 mPa·s.

[0026] The performance test data after the above installation process are as follows: Anchoring strength: 850 ± 15 MPa (average value of 10 groups of samples according to ASTM F606 standard); Sealing life: Simulate continuous operation for 12 months without leakage at a depth of 500 meters (5 MPa) underwater; Corrosion resistance: No pitting corrosion after 2000 hours of salt spray test (5% NaCl, 35°C) (ISO 9227).

[0027] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A stainless steel expansion bolt for underwater operations, characterized in that, Comprising: A bolt (4), the outer wall of the bolt (4) is provided with three parts, the two sides are provided with the same thread, the middle part on one side is provided with an opposite thread, and the ratio of the number of thread turns to the two sides is 2:1; A limiting ring (9), both sides of the limiting ring (9) are connected with a pressure suppressing block (10) through a limiting component, and the outer wall of the pressure suppressing block (10) is inclined outward, the middle part of the inner wall of the pressure suppressing block (10) is threadedly connected with one side of the bolt (4), one side of the pressure suppressing block (10) is rotationally connected with the end of the bolt (4), and the other side of the pressure suppressing block (10) is threadedly connected with the middle side of the bolt (4), so as to realize the displacement of the two pressure suppressing blocks (10) in a 2:1 relationship; A thin film capsule (2), the inside of the thin film capsule (2) is filled with a chemical agent, which is used to cement and fix the bolt (4) and the pressure suppressing block (10) in a drilling hole (11), so as to realize a composite part for anchoring a fixing part.

2. The stainless steel expansion bolt for underwater operation according to claim 1, characterized in that, The thin film capsule (2) is fixedly connected to the outer wall of the limiting ring (9) and is also fixedly connected to the outer wall of the pressure suppressing block (10).

3. The stainless steel expansion bolt for underwater operation according to claim 1, wherein, The limiting component includes a plug rod (12) that slides inside a slot (13), the slot (13) is opened on the side wall of the limiting ring (9), and the outer end of the plug rod (12) is fixedly connected to the side wall of the pressure suppressing block (10), which is used to limit the rotation of the pressure suppressing block (10).

4. The stainless steel expansion bolt for underwater operation according to claim 1, characterized in that, The other side of the bolt (4) is threadedly connected to a mounting hole (5), and the mounting hole (5) is opened on one side of a mounting cap (6), a gasket (7) is arranged on one side of the mounting cap (6), which is used to realize the sealing performance after installation, and a positioning ring (8) is sleeved on the other side of the bolt (4) to play a positioning role.

5. The stainless steel expansion bolt for underwater operation according to claim 1, characterized in that, The outer wall of the pressure suppressing block (10) is provided with holes, which are used to realize the extension of the chemical agent to both sides of the drilling hole (11) to achieve the effect of installation sealing.

6. The stainless steel expansion bolt for underwater operation according to claim 1, characterized in that, The chemical agent consists of the following components by mass percentage Composition: Epoxy resin matrix: 50% - 70%; Superabsorbent resin: 10% - 20%; Curing agent: 15% - 25%; Anti-aging agent: 2% - 5%; Silane coupling agent: 1% - 3%; Among them, the volume expansion rate of the superabsorbent resin after absorbing water is 300% - 500%, which is used to fill the microcracks between the anchor bolt and the base material and form a dense cured layer in cooperation with the epoxy resin; the anti-aging agent is uniformly dispersed in the matrix, which is used to inhibit the degradation of the resin under ultraviolet rays and humid and hot environments.

7. An underwater operation stainless steel expansion bolt according to claim 6, characterized in that, The silane coupling agent is γ-aminopropyltriethoxysilane (KH550) or γ-glycidoxypropyltrimethoxysilane (KH560), which is used to enhance the bonding strength between the chemical agent and the interfaces of the anchor bolt and the base material and form a hydrophobic barrier.

8. An underwater operation stainless steel expansion bolt according to claim 6, characterized in that, The superabsorbent resin is selected from sodium polyacrylate or starch-grafted acrylate, and the particle size is 50 - 150 μm, and the mixing viscosity with the epoxy resin is controlled at 500 - 1500 mPa·s to ensure the injection glue fluidity and expansion uniformity.

9. A sealing installation method for a stainless steel expansion bolt used in underwater operations, for a stainless steel expansion bolt used in underwater operations according to any one of claims 1-8, characterized in that, Including the following steps: Step 1: Drill a hole (11) in the base material, and use a high-pressure water jet to clean the debris and biological attachments in the hole; Step 2: Fix the thin film capsule (2) filled with chemical agent on the outer wall of the limiting ring (9) of the bolt (4), and insert the bolt (4) into the drilled hole (11). Step 3: Drive the two side pressing blocks (10) to expand inwards at a displacement ratio of 2:1 by rotating the bolt (4), squeeze the thin film capsule (2) until it ruptures, and release the chemical agent into the gap between the drilled hole (11) and the bolt (4). Step 4: The chemical agent absorbs water, swells and solidifies to form a dense anchoring layer, and at the same time, the inclined outer wall of the pressing block (10) is closely attached to the inner wall of the drilled hole (11). Step 5: Install a gasket (7) and a mounting cap (6) on the head of the bolt (4), apply a preset torque to complete the sealing, and verify the sealing performance through air pressure test or ultrasonic detection.

10. The sealing installation method of a stainless steel expansion bolt for underwater operations according to claim 9, characterized in that, In Step 3, the curing time of the chemical agent is 20 to 40 minutes, the curing temperature range is 5 to 40 °C, and the bolt (4) needs to be kept stationary during the curing process to avoid displacement of the anchoring layer.

Images