Flow Control - Dismantling Joints
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Dismantling Joints
Derwent Industries AFD10 and AFD20 dismantling joints are double flanged that provides easy installation and disassembly of flanged pipe and associated equipment including valves, meters and pumps. The AFD10 and AFD20 are widely used for a variety of applications in the water and waste water sectors, mining and industrial sectors. The operating principle behind the AFD10 and AFD20 is that the centre sealing flange is drawn closer to the mating flange, thereby compressing the rubber sealing ring to achieve a complete seal. So simple, yet so efficient and practical. The AFD10 features a single tie rod connecting all three flanges. The AFD20 features an end-to-end tie rod and a separate tie rod for the sealing flange. It is recommended to check with your local authority to confirm which series is permitted for your application.
FAQ
What is a dismantling joint and how does it work?
A dismantling joint is a double-flanged fitting designed to simplify the installation, positioning, and removal of flanged piping and inline equipment such as valves, flow meters, and pumps.
- Operating Principle: When the centre sealing flange is drawn closer to the mating flange via tie rods, it compresses an NBR rubber sealing ring to achieve a complete, bubble-tight seal.
- Adjustability: It provides essential longitudinal adjustment (telescopic clearance) to accommodate thermal expansion, soil movement, or alignment tolerances during maintenance and installation.
What are the main differences between the Derwent Industries AFD10 and AFD20 series?
While both series provide double-flanged convenience and longitudinal adjustment, their primary design differences lie in tie rod configurations and pressure ratings:
- Tie Rod Design: The AFD10 features a single tie rod connecting all three flanges (available in fully restrained and unrestrained configurations). The AFD20 features an end-to-end tie rod paired with a separate tie rod dedicated to the sealing flange, allowing additional tie rods for full end-load restraint.
- Pressure Class: The AFD10 Series is rated for PN16 pressure operations, whereas the AFD20 Series is rated for higher-pressure systems up to PN25.
- Longitudinal Adjustment Range:
AFD10: ±25 mm for sizes up to DN 750; ±30 mm for DN 800 and above.
AFD20: ±25 mm for sizes up to DN 600; ±30 mm for DN 700 and above
What size ranges, coatings, and standards compliance do AFD dismantling joints offer?
Derwent Industries dismantling joints are manufactured for demanding civil, water authority, and industrial standards:
- Size Availability: DN 50 to DN 1400 for AFD10; DN 100 to DN 1400 for AFD20 (with larger custom sizes available on request).
- Certifications & Coatings: WSAA appraised and coated with AS/NZS 4020 approved Fusion Bonded Epoxy (FBE) suitable for potable water applications.
- Flange Drilling Standards: Compatible with standard drilling patterns including AS 4087 CL16, AS 2129 Table E, ANSI 150 (drilling only), and EN 1092.
- Materials & Fasteners: Constructed with high-strength ductile iron bodies, standard 316 Teflon® coated stainless steel tie rods, and optional galvanised (4.8 / 8.8 class), 304 SS, or Dacromet® coated fasteners.
What are the primary applications for dismantling joints?
AFD10 and AFD20 dismantling joints are widely utilized across:
- Municipal Water & Wastewater: Pump stations, treatment plants, water storage reservoirs, and pipeline mains.
- Mining & Industrial Processing: Dewatering, slurry transport, and industrial utility piping lines.
- Inline Equipment Servicing: Placed adjacent to heavy gate valves, check valves, flow meters, or pumps to allow fast equipment pull-out without cutting or forcing rigid pipe sections.
Dismantling Joints Series Comparison
| Feature | AFD10 Series | AFD20 Series |
|---|---|---|
| Size Range | DN 50 – DN 1400 | DN 100 – DN 1400 |
| Pressure Rating | PN16 | PN25 |
| Tie Rod Style | Single tie rod connecting all 3 flanges | End-to-end tie rod + separate sealing flange tie rod |
| Restraint Options | Fully restrained & unrestrained configurations | Can be supplied with additional tie rods for full end-restraint |
| Adjustability | ±25 mm (≤DN 750), ±30 mm (≥DN 800) | ±25 mm (≤DN 600), ±30 mm (≥DN 700) |
| Body & Coating | Ductile Iron body with AS/NZS 4020 FBE coating | Ductile Iron body with AS/NZS 4020 FBE coating |
| WSAA Appraised | Yes | Yes |