Customer Case Studies
Real-world project documentation from Anhui Tongfa field engineers and municipal water utility operators across China and export markets. Cases cover emergency repair, planned maintenance, branch tapping, pipeline transitions, and large-diameter custom work.
Emergency Live-Line Repair of Large-Diameter Cast Iron Water Main
📍 Municipal Water Utility — Anhui Province, China
Products used: Cast Iron Socket & Straight-Pipe Repair Clamps (DN200–DN1200)
Challenge
A DN800 cast iron water main developed a circumferential crack at a bell-and-spigot socket joint under 0.6 MPa operating pressure. Traditional repair would require a 12-hour service shutdown affecting 150,000 residents.
Solution
Field crews applied a custom-sized socket repair clamp (铸铁管承插哈夫节) over the leaking joint without shutting down the line. The ductile iron shell with EPDM lip seal was clamped in position in under 90 minutes. A parallel project on the same main used straight-pipe sleeve clamps at two barrel-leak locations.
Result
All three repairs completed in under 4 hours with zero service interruption. Post-repair pressure test passed at 1.0 MPa. Clamps designed for 15+ year service life.
Pressurized Hot-Tapping for New Service Branch on Active Water Main
📍 Urban Water Distribution Network — Jiangsu Province, China
Products used: DK6 Electric Tapping Machine + Haff-Type Saddle Clamp
Challenge
A new residential development required a DN150 branch off an existing DN400 ductile iron water main operating at 0.4 MPa. The main serves a major hospital and cannot be shut down.
Solution
A haff-type saddle clamp (铸铁管哈夫式管卡) was installed over the DN400 main first, followed by the DK6 electric tapping machine. The machine drilled through the live main under full pressure, and the new branch valve was inserted without any service interruption. The entire operation was completed by a two-person crew.
Result
New DN150 branch connected in 6 hours with no downtime. Hospital water supply unaffected. The tapping machine and saddle clamp combination is now the standard method for this utility for all branch connections DN80–DN300.
Multi-Material Pipeline Transition Using Universal Connectors
📍 Industrial Water Supply Upgrade — Guangdong Province, China
Products used: Universal Connectors, Double-Socket Connectors, Flanged Expansion Joints
Challenge
An industrial facility was upgrading its water supply system, requiring connections between sections of old grey cast iron (DN300), new ductile iron (DN300), and HDPE (DN280) pipe. Standard fittings could not bridge the OD differences and material transitions.
Solution
A combination of universal connectors (万能连接器) and double-socket connectors (双向承插连接器) were used to make all transitions. The universal connectors accepted the varying ODs (320 mm CI vs. 310 mm DI) without machining. Flanged expansion joints were installed at critical anchor points to absorb thermal movement.
Result
Entire 420-metre pipeline transition completed in two weeks. No field machining required. Leak-free post-commissioning at 0.8 MPa operating pressure.
In-Line Pipe Cutting for Emergency Pipe Section Replacement
📍 Gas Distribution Network — Zhejiang Province, China
Products used: WDG4-1 Self-Climbing Universal Pipe Cutting Machine
Challenge
A 3-metre section of DN200 steel gas main was severely corroded and had to be cut out and replaced. The pipe was in a congested underground utility corridor with no room for disc-angle grinders or pipe saws.
Solution
The WDG4-1 self-climbing cutting machine was clamped around the pipe outside the trench. Its motorized cutting wheel ran a clean circumferential cut at each end of the damaged section. The machine operates without electricity (pneumatic drive also available) and fits pipes DN100–DN600 in tight spaces.
Result
Both cuts completed in under 2 hours. Perfectly square, burr-free cuts. New pipe section welded in and the gas main back in service the same day.
Custom Large-Diameter Repair Clamps for DN1400–DN2000 Steel Mains
📍 Bulk Water Transmission — Multiple Provinces, China
Products used: Custom Repair Clamps DN1400–DN2000 (Non-Standard)
Challenge
Several bulk water transmission utilities needed repair clamps for DN1400, DN1600, and DN2000 steel mains — sizes not available from standard catalogue stock. These high-pressure (0.8–1.6 MPa) mains carry treated water across provincial boundaries and any leak creates significant water loss.
Solution
Anhui Tongfa engineering team designed and manufactured custom multi-segment clamps (4–6 segments for DN2000) with heavy-wall QT500-7 shells and wide-profile EPDM seals. Each clamp was hydrostatically tested to 1.5× rated pressure before delivery. Installation used hydraulic torque tools for consistent bolt preload.
Result
Fourteen custom clamps delivered across five projects in 2024–2025. All passed field acceptance tests. Lead time 15–25 working days from drawing approval. DN2000 clamps weigh approximately 850 kg and require a crane for installation.
