Background

A municipal sewage authority had been operating clay and concrete drainage pipes installed in the 1970s. With the city expanding rapidly and infrastructure standards tightening, local authorities mandated an upgrade to modern polymer pipes across 280 km of sewage infrastructure.

The authority's procurement team began evaluating corrugated pipe production equipment in early 2022. Their requirement: a self-sufficient domestic production capability for ID 500mm PP double-wall corrugated pipes at a minimum output of 400 kg/h.

Why Suba

After reviewing four international suppliers, the authority's engineering department shortlisted Suba Machinery based on:

Patent portfolio — 13+ utility model and invention patents covering the horizontal water-cooling structure
Fourth-generation water cooling — consistent pipe quality at high output speeds
After-sales commitment — remote support and spare parts supply without a distributor markup
Reference sites — existing Suba installations in the region verified by video call

The sales process involved three rounds of technical questionnaires, one remote demo via live video feed from Qingzhou, and a factory visit by two engineers from the authority.

Order and Production

The SL600 production line was specified with:

Twin-screw extruder, output 450–480 kg/h
Online double-layer socket forming
Full PLC automation, Siemens components
Non-disassembling mould change system for switching between ID 400, 500, and 600mm dies

Lead time from contract signing to factory acceptance test: 11 weeks. The authority's two engineers attended the FAT in Qingzhou for 5 days, running the line at 100% capacity and approving all pipe samples to applicable local standards.

Shipment

The complete line was packed into 4×40ft HC containers and shipped from Qingdao Port to the destination port. Transit time: 28 days.

Customs clearance was handled by the authority's freight agent. Suba provided full packing lists, CE declarations, and bilingual manuals. All crates arrived with zero transport damage.

Installation and Commissioning

Suba dispatched two installation engineers to the authority's facility for a 12-day on-site commissioning:

Days 1–3: mechanical assembly and alignment
Days 4–6: electrical connection, PLC programming, safety interlocks
Days 7–9: trial runs, die head calibration, pipe sampling
Days 10–12: operator training (8 staff certified), production handover

First production run: 492 kg/h, exceeding the 400 kg/h requirement.

Results in Operation

18 months into production, the authority's facility is operating two 8-hour shifts daily, producing approximately 7,500 tonnes of pipe per year. Downtime has averaged less than 2% — primarily scheduled maintenance.

The authority has since placed a second order for a SL300 line to cover smaller-diameter drainage pipes for residential zones.

*"The commissioning team from Suba was professional and thorough. They did not leave until every operator was confident. After 18 months, the line runs as well as day one."*