Hongze Valve
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Dismantling Joint – Double Gland Type
The Dismantling Joint – Double Gland Type (also called Double Gland Loose Sleeve Joint, Double Compression Sleeve Joint, Mechanical Compression Coupling) is a highly flexible pipe connector designed for easy, flange-free installation and maintenance. Unlike standard flanged dismantling joints, this design features compression glands on both ends, allowing you to insert steel, ductile iron, or PVC pipes directly into the joint and secure them tightly using mechanical compression bolts.
This double compression sleeve joint provides excellent sealing performance, absorbs minor axial movement and vibration, and allows for quick connection or disconnection of pipes without the need for welding or flanges. Its innovative structure makes it ideal for pipeline repairs, extensions, emergency connections, and retrofit projects—especially where space is limited or flange installation is not feasible.
Manufactured from durable ductile iron or carbon steel, and lined with high-quality rubber gaskets (EPDM, NBR, or customized), this joint ensures a leak-proof, corrosion-resistant, and long-lasting connection even under high pressure and various environmental conditions.
Typical applications include municipal water supply, industrial pipelines, wastewater systems, fire protection, and any project that requires rapid, reliable, and flexible mechanical pipe connections without the use of flanges.
Key Features
Technical Specifications
| Nominal Diameter (DN) | Inch | Total Length (L) mm | Pipe Insertion Depth (mm) | Gland Thickness (mm) | Gland Bolt Qty (pcs) | Suitable Pipe OD (mm) | Axial Adjustment Range (mm) |
|---|
| DN50 | 2″ | 180 | 65 | 16 | 4 | 60.3 | 10 |
| DN65 | 2.5″ | 200 | 75 | 18 | 4 | 76.1 | 10 |
| DN80 | 3″ | 210 | 80 | 20 | 6 | 88.9 | 12 |
| DN100 | 4″ | 230 | 90 | 22 | 6 | 114.3 | 12 |
| DN125 | 5″ | 250 | 100 | 24 | 8 | 139.7 | 14 |
| DN150 | 6″ | 270 | 110 | 26 | 8 | 168.3 | 14 |
| DN200 | 8″ | 300 | 120 | 28 | 10 | 219.1 | 16 |
| DN250 | 10″ | 340 | 130 | 30 | 12 | 273.0 | 16 |
| DN300 | 12″ | 370 | 140 | 32 | 12 | 323.9 | 18 |
| DN350 | 14″ | 410 | 150 | 34 | 14 | 355.6 | 18 |
| DN400 | 16″ | 440 | 160 | 36 | 16 | 406.4 | 18 |
| DN450 | 18″ | 480 | 170 | 38 | 16 | 457.0 | 20 |
| DN500 | 20″ | 500 | 180 | 40 | 20 | 508.0 | 20 |
| DN600 | 24″ | 540 | 200 | 44 | 20 | 610.0 | 20 |
| Parameter | Unit | Specification |
|---|---|---|
| Product Name | – | Compression Sleeve Coupling (Double Gland Type) |
| Model Code | – | ZD-CSC (Compression Sleeve Coupling) |
| Nominal Diameter Range | mm | DN50 – DN600 |
| Connection Type | – | Double Compression Gland (No Flange) |
| Working Pressure Levels | MPa / Bar | PN10 (1.0 MPa), PN16 (1.6 MPa), PN25 (2.5 MPa) |
| Axial Adjustment Range | mm | 10 – 20 (depends on DN size) |
| Pipe Insertion Depth | mm | 65 – 200 (depends on DN size) |
| Shell Pressure Test | MPa | 1.5 × Working Pressure |
| Sealing Pressure Test | MPa | 1.1 × Working Pressure |
| Sealing Performance | – | Zero visible leakage at rated pressure |
| Angular Deflection | ° | ≤ 8° |
| Lateral Displacement | mm | Up to 20 |
| Applicable Temperature | °C | -20°C ~ +120°C (depends on gasket material) |
| Gasket Material | – | EPDM, NBR, PTFE |
| Service Life | years | ≥ 25 years (normal conditions) |
| Component | Material Option 1 | Material Option 2 | Application Notes |
|---|---|---|---|
| Main Body | Ductile Iron (GGG40/50) | Carbon Steel (Q235/Q345) | Standard for water supply and industrial pipelines |
| Compression Gland Ring | Ductile Iron | Stainless Steel (SS304/316) | For mechanical sealing and clamping |
| Inner Sleeve | Carbon Steel | Stainless Steel | Telescopic section, direct pipe contact |
| Sealing Gasket | EPDM | NBR / PTFE | EPDM: Water/air; NBR: Oil/fuel; PTFE: Chemicals |
| Bolts & Nuts | Carbon Steel, Zinc Plated | Stainless Steel | Number and size vary with DN and pressure |
| Surface Coating | Fusion Bonded Epoxy (FBE) ≥250μm | Bitumen Paint / Bare SS | FBE standard, bitumen for buried; SS can be uncoated |
| Surface Finish | Shot-blasted to Sa2.5 | Polished & Passivated (SS) | Improves coating adhesion; passivation for chemicals |
| Step | Installation Task | Detailed Procedure & Instructions |
|---|---|---|
| 1 | Pre-Installation Inspection | – Check product for damage, deformation, or missing parts – Confirm all bolts, gaskets, gland rings are included |
| 2 | Pipeline Preparation | – Pipe ends must be clean, flat, and burr-free – Ensure pipe axes are aligned and level |
| 3 | Pipe Insertion | – Insert pipe ends fully into both sides of the inner sleeve – Ensure equal insertion depth |
| 4 | Gasket Placement | – Place sealing gaskets inside gland rings – Ensure gasket is centered and free from folds |
| 5 | Gland Ring Installation | – Position gland rings over pipe ends – Insert bolts through flanges and start hand-tightening |
| 6 | Bolt Tightening (Cross Pattern) | – Tighten bolts in a crisscross/star pattern – Use wrench to apply gradual pressure |
| 7 | Final Torque Application | – Use torque wrench to reach specified torque (based on size & pressure) – Avoid over-tightening |
| 8 | Axial Adjustment (if required) | – Slightly slide joint to adjust length before final tightening – Leave expansion room if needed |
| 9 | Sealing Verification | – Ensure gasket is evenly compressed – No extrusion or misalignment of sealing rings |
| 10 | Pressure Test | – Perform hydrostatic test at 1.5× working pressure – Check for leaks around flange and gland |
| ✅ | Commissioning | – Once leak-free, put into service – Record torque values and date for maintenance reference |
⚠️ Important Notes
| Item | Best Practice |
|---|---|
| Gasket Installation | Center gasket carefully; avoid folds or displacement |
| Bolt Tightening Pattern | Tighten in cross/star pattern to ensure even compression |
| Pipeline Support | Do not allow joint to bear pipe weight; use pipe supports on both sides |
| Underground Use | Use bitumen wrap or protective sleeves for buried installations |
| Axial Movement Function | Leave slight axial room if acting as flexible connector |
| Maintenance Task | Recommended Frequency | Procedure & Instructions | Purpose / Result |
|---|---|---|---|
| 🔍 Visual Inspection | Monthly / Quarterly | – Inspect outer surfaces for rust, peeling coating, or visible damage – Check for gasket extrusion or flange leakage | Early detection of deterioration and safety assurance |
| 🔧 Compression Bolt Retightening | Every 6 months | – Use torque wrench to recheck and retighten gland bolts – Follow original cross-sequence pattern | Prevent leakage due to vibration, relaxation, or gasket compression loss |
| 🧪 Seal Integrity & Gasket Check | Every 6–12 months | – Inspect compression gasket condition: cracks, hardening, or flattening – Replace if any abnormal wear is found | Maintain effective sealing and prevent sudden failure |
| 🧱 Sleeve Movement Verification | Annually | – Ensure sleeve is not seized due to rust or over-tightening – Confirm axial adjustability if used for expansion | Retains joint flexibility and thermal compensation function |
| 🎨 Surface Coating Maintenance | Annually / As needed | – Clean the joint surface and reapply FBE or anti-corrosive coating – For buried joints, check wrapping condition | Protects steel structure and extends service life |
| 🔩 Fastener Replacement | Every 3–5 years | – Replace flange bolts and nuts if they show signs of corrosion or thread damage – Use same material grade or equivalent | Ensure reliable flange connection and mechanical integrity |
| 🧾 Maintenance Record Keeping | After every service | – Record date, torque values, replaced parts, and inspector name – Attach photos if abnormality is found | Supports long-term traceability and warranty-related technical verification |
⚠️ Common Failure Scenarios & Solutions
| Symptom | Likely Cause | Recommended Action |
|---|---|---|
| Gasket leakage | Gasket aged, loose bolts, or poor installation | Replace gasket; retorque compression bolts evenly |
| Gasket extrusion | Overcompression or oversized axial movement | Replace gasket with correct size; recheck bolt torque and pipe fit |
| Bolt thread corrosion | Humid environment or coating failure | Replace bolts and repaint or galvanize contact areas |
| Sleeve jamming / no axial movement | Rust accumulation or overtight installation | Clean and re-grease sleeve area; disassemble if necessary |
✅ Recommended Spare Parts
Compression Gaskets (EPDM / NBR / PTFE – based on working media)
Full Bolt & Nut Kits (galvanized carbon steel or stainless steel)
Anti-corrosion Coating (FBE patch kits or bituminous paint)
What is a Double Gland Dismantling Joint and how does it differ from traditional flange joints?
A Double Gland Dismantling Joint is a pipe connector that uses compression glands on both ends, allowing pipes to be directly inserted and secured without flanges or welding. Unlike traditional flange joints, it enables fast, flexible installation and disassembly, making it ideal for repairs and confined spaces.
What types of pipes are compatible with this joint?
This joint is compatible with steel pipes, ductile iron pipes, PVC pipes, and other standard pipe materials. It is designed for use in both new pipeline installations and retrofit projects.
Where is the Double Gland Dismantling Joint typically used?
It is widely used in municipal water supply systems, wastewater pipelines, fire protection networks, and industrial facilities—especially in applications where rapid installation or maintenance is needed and flanged connections are not practical.
What are the main advantages of using a double compression sleeve joint?
The main advantages include quick and easy installation, excellent sealing performance, ability to absorb vibration and axial movement, and suitability for environments where corrosion resistance and long service life are required.
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