A stainless steel expansion bolt for underwater operation and its sealing installation method

Abstract

The present invention relates to the field of marine engineering technology, and provides a stainless steel expansion bolt for underwater operations, comprising: a bolt, wherein the outer wall of the bolt is configured as three parts, both sides adopt the same thread setting, and one side of the middle part is configured as an opposite thread, and the ratio of the number of threads to the two sides is 2:1; a limiting ring, wherein both sides of the limiting ring are connected with a pressure suppression block through a limiting assembly, and the outer wall of the pressure suppression block is configured to be inclined outward, the middle part of the inner wall of the pressure suppression block is connected to one side of the bolt by thread, and one side of the pressure suppression block is rotatably connected to the end of the bolt. By adopting a duplex stainless steel body and a titanium nitride coating, the ability to resist chloride ion corrosion is significantly improved; the anti-aging agent in the chemical agent can inhibit ultraviolet and wet heat degradation, and in the double sealing system, combined with the water absorption and expansion of the chemical agent, it effectively fills the gap in the base material and forms a dense solidified layer, with an anchoring strength ≥800MPa and a sealing pressure ≥1.5 times the working water pressure.

Description

Technical Field

[0001] The invention relates to the technical field of marine engineering, in particular to a stainless steel expansion bolt for underwater operation and a sealing installation method thereof. Background Art

[0002] Underwater expansion bolts, key components in marine engineering, subsea facility installation, and underwater structure repair, must provide stable anchoring and sealing in high-pressure, high-humidity, and high-salt corrosive environments. Traditional bolts are typically made of ordinary stainless steel or plated metal, secured through mechanical expansion or chemical bonding. However, their performance is limited by the material's corrosion resistance, sealing structure design, and chemical compatibility, making them difficult to meet the long-term reliability requirements of deep-sea operations.

[0003] Currently, underwater expansion bolts are prone to pitting or stress corrosion cracking due to long-term immersion. The sealing structure is simple and relies on static sealing rings or adhesives, which cannot adapt to dynamic water pressure fluctuations, leading to leakage risks. The chemical anchoring agents used have a slow curing speed and low expansion rate, making it difficult to fill micro-cracks in the substrate and have poor aging resistance. The installation process is complicated and the torque control is imprecise, which can easily cause uneven anchoring layers or loose bolts. Summary of the Invention

[0004] In response to the shortcomings of the existing technology, the present invention provides a stainless steel expansion bolt for underwater operations and a sealed installation method thereof. By optimizing the bolt structure, adopting corrosion-resistant alloys, developing high-expansion rate chemicals, and combining a phased installation process, the present invention aims to solve the core problems of the existing technology, such as anchor failure, insufficient sealing, and short service life.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: A stainless steel expansion bolt for underwater operation, comprising:

[0006] The outer wall of the bolt is configured as three parts, with the same thread setting on both sides and the thread setting on the middle part opposite to the two sides, and the ratio of the number of threads to the two sides is 2:1;

[0007] The two sides of the limiting ring are connected with the pressure suppression block through the limiting assembly, and the outer surface of the pressure suppression block is

[0008] The wall is tilted outward, and the middle of the inner wall of the pressure suppression block is connected to one side of the bolt by thread. The pressure suppression block on one side is rotatably connected to the end of the bolt, and the pressure suppression block on the other side is connected to the middle side of the bolt by thread, so that the pressure suppression blocks on both sides can be displaced in a 2:1 relationship.

[0009] The film sac is filled with chemicals for bonding the bolts and the pressure suppression blocks to the drill holes, thereby achieving the function of anchoring the fixing parts.

[0010] Preferably, the film capsule is fixedly connected to the outer wall of the limiting ring and is also fixedly connected to the outer wall of the pressure suppression block.

[0011] Preferably, the limiting assembly includes an insert rod sliding inside a slot, the slot is provided on the side wall of the limiting ring, and the outer end of the insert rod is fixedly connected to the side wall of the pressure suppression block to limit the rotation of the pressure suppression block.

[0012] Preferably, the other side of the bolt is threadedly connected to the mounting hole, and the mounting hole is opened on one side of the mounting cap. A gasket is provided on one side of the mounting cap to achieve sealing after installation, and a positioning ring is provided on the other side of the bolt for positioning.

[0013] Preferably, holes are provided on the outer wall of the pressure suppression block to allow the chemical agent to extend to both sides of the drill hole to achieve the installation sealing effect.

[0014] Preferably, the chemical agent is composed of the following components in percentage by mass:

[0015] Epoxy resin matrix: 50% to 70%;

[0016] Super absorbent resin: 10% to 20%;

[0017] Curing agent: 15% to 25%;

[0018] Anti-aging agent: 2% to 5%;

[0019] Silane coupling agent: 1% to 3%;

[0020] Among them, the super absorbent resin has a volume expansion rate of 300% to 500% after absorbing water, and is used to fill the microcracks between the anchor bolt and the substrate, and cooperates with the epoxy resin to form a dense solidified 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.

[0021] Preferably, the silane coupling agent is γ-aminopropyltriethoxysilane (KH550) or γ-

[0022] Glyceryl etheroxypropyl trimethoxysilane (KH560) is used to enhance the bonding strength between the chemical agent, the anchor bolt and the substrate interface and to form a hydrophobic barrier.

[0023] Preferably, the super absorbent resin is selected from sodium polyacrylate or starch grafted acrylate, and has a particle size of 50 to 150 μm. The viscosity of the mixture with the epoxy resin is controlled at 500 to 1500 mPa·s to ensure injection fluidity and expansion uniformity.

[0024] A method for sealing and installing stainless steel expansion bolts for underwater operations comprises the following steps:

[0025] Step 1: Drill a hole in the substrate and use a high-pressure water jet to clean the debris and biological attachments in the hole;

[0026] Step 2: Fix the film bag filled with chemicals to the outer wall of the limiting ring of the bolt, and insert the bolt into the drilled hole;

[0027] Step 3: Rotate the bolts to drive the pressure suppression blocks on both sides to expand inward at a displacement ratio of 2:1, squeezing the membrane capsule until it ruptures and releasing the chemical into the gap between the drill hole and the bolts;

[0028] Step 4: The chemical agent absorbs water, expands, and solidifies to form a dense anchoring layer, while the inclined outer wall of the pressure suppression block is tightly attached to the inner wall of the borehole;

[0029] Step 5. Install the gasket and mounting cap on the bolt head, apply the preset torque to complete the seal, and verify the sealing through air pressure test or ultrasonic test.

[0030] Preferably, the curing time of the chemical agent in step 3 is 20 to 40 minutes, the curing temperature range is 5 to 40° C., and the bolts need to be kept stationary during the curing process to avoid displacement of the anchoring layer.

[0031] The present invention provides a stainless steel expansion bolt for underwater operation and a sealing installation method thereof. It has the following beneficial effects:

[0032] 1. The present invention significantly improves the resistance to chloride ion corrosion by adopting a duplex stainless steel body and a titanium nitride coating; the anti-aging agent in the chemical agent can inhibit ultraviolet and heat degradation, and in the double sealing system, combined with the water absorption and expansion of the chemical agent, it effectively fills the gap between the substrates and forms a dense solidified layer, with an anchoring strength of ≥800MPa and a sealing pressure of ≥1.5 times the working water pressure.

[0033] 2. The present invention adopts a split expansion sleeve and a 2:1 displacement ratio design of the pressure suppression block to ensure uniform expansion; the chemical agent curing time is controllable and adapted to water temperatures of 5 to 40°C; and the tightening is carried out in stages with IP68 waterproof tools.

[0034] The torque accuracy is ±3%, which avoids displacement of the anchoring layer, supports underwater operations at a depth of 500 meters, and has been double-verified by air pressure testing and ultrasonic testing for sealing, making it suitable for complex marine environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagram of the internal structure of the limiting ring in the present invention;

[0036] Figure 2 Schematic diagram of the internal structure of the drilling hole in the present invention;

[0037] Figure 3 For the present invention Figure 2 Enlarged view of point A in the middle.

[0038] Among them, 1. underwater equipment; 2. membrane bag; 3. positioning block; 4. bolt; 5. mounting hole; 6. mounting cap; 7. gasket; 8. positioning ring; 9. limit ring; 10. pressure suppression block; 11. drilling hole; 12. plug rod; 13. slot. DETAILED DESCRIPTION

[0039] 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. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0040] Example:

[0041] 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, comprising:

[0042] The outer wall of the bolt 4 is set to three parts, with the same thread setting on both sides, and the middle side is set to the opposite thread, and the ratio of the number of threads on both 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 set 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. The sealing is verified by air pressure test or ultrasonic test to achieve the sealing after installation. A positioning ring 8 is provided on the other side of the bolt 4 for positioning. The pressure suppression blocks 10 on both sides are driven by rotating the bolt 4 to

[0043] The displacement ratio of 2:1 expands inward, squeezing the membrane capsule 2 until it ruptures, releasing the chemical into the gap between the drill hole 11 and the bolt 4;

[0044] The side wall of the limiting ring 9 is provided with a slot 13, and a rod 12 is inserted into the slot 13 to slide. The outer end of the rod 12 is fixedly connected to the side wall of the pressure suppression block 10 to limit the rotation of the pressure suppression block 10. The outer wall of the pressure suppression block 10 is inclined outward. The middle part of the inner wall of the pressure suppression block 10 is threadedly connected to one side of the bolt 4. The pressure suppression block 10 on one side is rotatably connected to the end of the bolt 4, and the pressure suppression block 10 on the other side is threadedly connected to the middle side of the bolt 4 to achieve displacement of the pressure suppression blocks 10 on both sides in a 2:1 relationship. Holes are provided on the outer wall of the pressure suppression block 10 to allow chemicals to extend to both sides of the drill hole 11 to achieve the installation and sealing effect.

[0045] The interior of the film sac 2 is filled with chemicals, which are used to glue and fix the bolt 4 and the pressure suppression block 10 in the borehole 11 to achieve the function of anchoring the fixing part. The film sac 2 is located on the outer wall of the limiting ring 9 and is fixedly connected to the outer wall of the pressure suppression block 10. The chemical absorbs water, expands and solidifies to form a dense anchoring layer, and at the same time fits tightly with the inner wall of the borehole 11 through the inclined outer wall of the pressure suppression block 10.

[0046] As another aspect of the present invention, the chemical agent in the stainless steel expansion bolt for underwater operation is composed of the following components in percentage by mass:

[0047] Epoxy resin matrix: 50% to 70%;

[0048] Super absorbent resin: 10% to 20%;

[0049] Curing agent: 15% to 25%;

[0050] Anti-aging agent: 2% to 5%;

[0051] Silane coupling agent: 1% to 3%;

[0052] The super absorbent resin has a volume expansion rate of 300% to 500% after absorbing water, and is used to fill the micro-cracks between the anchor bolt and the substrate, and cooperates with the epoxy resin to form a dense solidified layer. The anti-aging agent is evenly dispersed in the matrix to inhibit the degradation of the resin under ultraviolet light and humid and hot environments.

[0053] The silane coupling agent is γ-aminopropyltriethoxysilane KH550 or γ-glycidyloxypropyltrimethoxysilane KH560, which is used to enhance the bonding strength between the chemical agent and the anchor bolt and substrate interface and form a hydrophobic barrier.

[0054] The super absorbent resin is selected from sodium polyacrylate or starch grafted acrylate, and the particle size is 50 to 150

[0055] μm, and the mixed viscosity with epoxy resin is controlled at 500~1500mPa·s to ensure the fluidity of injection and uniformity of expansion.

[0056] A method for sealing and installing stainless steel expansion bolts for underwater operations comprises the following steps:

[0057] Step 1: Drill a hole 11 in the substrate and use a high-pressure water jet to clean the debris and biological attachments in the hole;

[0058] Step 2: Fix the film capsule 2 filled with chemicals to the outer wall of the limiting ring 9 of the bolt 4, and insert the bolt 4 into the drilled hole 11;

[0059] Step 3: Rotate the bolt 4 to drive the pressure suppression blocks 10 on both sides to expand inward at a displacement ratio of 2:1, squeezing the film capsule 2 until it ruptures and releasing the chemical into the gap between the drill hole 11 and the bolt 4. The chemical cures for 20 to 40 minutes at a temperature range of 5 to 40°C. During the curing process, the bolt 4 must be kept stationary to prevent displacement of the anchor layer.

[0060] Step 4: The chemical absorbs water, expands, and solidifies to form a dense anchoring layer, while the inclined outer wall of the pressure suppression block 10 is closely attached to the inner wall of the borehole 11;

[0061] Step 5: Install the gasket 7 and the mounting cap 6 on the head of the bolt 4, apply the preset torque to complete the seal, and verify the sealing through air pressure test or ultrasonic test.

[0062] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A stainless steel expansion bolt for underwater operation, characterized in that: include: A bolt (4), wherein the outer wall of the bolt (4) is configured as three parts, with the same thread arrangement being used on both sides, and a middle part having a thread arrangement opposite to that of the two sides, and a thread number ratio of 2:1 to that of the two sides; A limiting ring (9), wherein both sides of the limiting ring (9) are connected to pressure suppressing blocks (10) through limiting components, 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 connected to one side of the bolt (4) by thread, the pressure suppressing block (10) on one side is connected to the end of the bolt (4) by rotation, and the pressure suppressing block (10) on the other side is connected to the middle side of the bolt (4) by thread, so as to realize displacement of the pressure suppressing blocks (10) on both sides in a 2:1 relationship; A film sac (2) is filled with a chemical agent for gluing and fixing the bolt (4) and the pressure suppression block (10) in the drill hole (11) to achieve the function of anchoring the fixing member. The film sac (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 suppression block (10).

2. The stainless steel expansion bolt for underwater operation according to claim 1, characterized in that: The limiting assembly includes an insert 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 insert rod (12) is fixedly connected to the side wall of the pressure suppression block (10) to limit the rotation of the pressure suppression block (10).

3. 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 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) to achieve sealing after installation. The other side of the bolt (4) is sleeved with a positioning ring (8) for positioning.

4. The stainless steel expansion bolt for underwater operation according to claim 1, characterized in that: The outer wall of the pressure suppression block (10) is provided with holes for allowing the chemical agent to extend to both sides of the drill hole (11) to achieve the function of installation sealing.

5. The stainless steel expansion bolt for underwater operation according to claim 1, characterized in that: The chemical agent consists of the following components in percentage by weight composition: Epoxy resin matrix: 50% to 70%; Super absorbent resin: 10% to 20%; Curing agent: 15% to 25%; Anti-aging agent: 2% to 5%; Silane coupling agent: 1% to 3%; Among them, the super absorbent resin has a volume expansion rate of 300% to 500% after absorbing water, and is used to fill the microcracks between the anchor bolt and the substrate, and cooperates with the epoxy resin to form a dense solidified 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.

6. The stainless steel expansion bolt for underwater operation according to claim 5, characterized in that: The silane coupling agent is γ-aminopropyltriethoxysilane (KH550) or γ-glycidyloxypropyltrimethoxysilane (KH560), which is used to enhance the bonding strength between the chemical agent and the anchor bolt and substrate interface and form a hydrophobic barrier.

7. The stainless steel expansion bolt for underwater operation according to claim 5, characterized in that: The highly absorbent resin is selected from sodium polyacrylate or starch grafted acrylate, and has a particle size of 50 to 150 μm. The viscosity of the mixture with the epoxy resin is controlled at 500 to 1500 mPa·s to ensure injection fluidity and expansion uniformity.

8. A method for sealing and installing a stainless steel expansion bolt for underwater operation, according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1: Drill a hole (11) in the substrate and use a high-pressure water jet to clean the debris and biological attachments in the hole; Step 2: Fix the film capsule (2) filled with chemical agents to 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 pressure suppression blocks (10) on both sides to the right at a displacement ratio of 2:1 by rotating the bolts (4). Expanding internally, squeezing the membrane capsule (2) until it ruptures, and releasing the chemical agent into the gap between the drill hole (11) and the bolt (4); Step 4: The chemical agent absorbs water, expands, and solidifies to form a dense anchoring layer, and at the same time, the inclined outer wall of the pressure suppression block (10) is tightly attached to the inner wall of the drill hole (11); Step 5: Install the gasket (7) and the mounting cap (6) on the head of the bolt (4), apply the preset torque to complete the seal, and verify the sealing performance through air pressure testing or ultrasonic testing.

9. The method for sealing and installing stainless steel expansion bolts for underwater operations according to claim 8, characterized in that: The curing time of the chemical agent in step 3 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.

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