I. Case Background: Selection Challenges for Sewer Cleaning Trucks under High Rainy-Season Load In summer 2025, the municipal sanitation department of a district in Guiyang City discovered during routine pipeline maintenance that severe silt accumulation had occurred in the urban drainage system due to continuous rainfall. Aging sewer cleaning trucks experienced frequent failures, prompting an urgent need to procure a batch of blue-license-plate sewer cleaning trucks suitable for local operating conditions. According to publicly released tender information, the project budget was capped at approximately RMB 1.65 million, with plans to purchase five Dongfeng single-cab, blue-license-plate, 5-cubic-meter sewer cleaning trucks for sewer cleaning operations in residential communities, narrow alleys, and municipal roads. The department head stated: 'Guiyang is located in Southwest China; summers are hot and humid with abundant rainfall, resulting in high-moisture, highly corrosive silt. Moreover, operational frequency is 1.5 times higher than that in plain regions. Our biggest concern is rapid vehicle corrosion and premature aging of sealing components—leading to air leakage and hydraulic system failure.' After extensive evaluation, Chengli Special Purpose Vehicle Co., Ltd. ultimately delivered five Dongfeng single-cab, blue-license-plate, 5-cubic-meter sewer cleaning trucks, along with a targeted customization solution. II. Solution Overview: How Chengli Addresses Humid-Heat Environments and High-Load Operations After understanding the customer’s requirements, Chengli’s technical team optimized the CLW5040TQYD6 chassis model (technical parameters sourced from MIIT official announcements) across three key aspects: 1. Anti-Corrosion Coating: Full-Vehicle Hot-Dip Galvanizing + Epoxy Primer To counteract Guiyang’s high humidity and acidic rain, Chengli applied hot-dip galvanizing to the tank body, hydraulic oil tank, and bolted joints, followed by epoxy anti-corrosion primer coating. Compared to standard paint finishes, salt-spray resistance increased to over 1,000 hours. Customer feedback: 'After three months of use, no red rust has appeared at frame connection points—far superior to our previous vehicles.' 2. Sealing Component Durability: Imported Nitrile Rubber + Dust Covers Hydraulic system and tank sealing components utilize oil- and acid-resistant nitrile rubber, supplemented with dust covers to prevent silt and sand ingress into sealing surfaces. No leakage occurred during 20 consecutive days of rainy-day operation. A Chengli after-sales engineer explained: 'Nitrile rubber maintains reliable sealing performance at oil temperatures of 50–80°C, making it ideal for frequent start-stop operational cycles.' 3. High-Load Operation Assurance: Reinforced Hydraulic System Standard configuration includes a dual-gear pump and oil cooler to withstand frequent suction and discharge operations. Hydraulic piping is made of stainless steel to prevent corrosion-induced blockages. During summer heavy-rain periods, this truck achieved up to eight hours of daily operation, with hydraulic system temperature consistently maintained below 70°C. III. Equipment Comparison: Chengli Custom Solution vs. Market-Standard Configuration To clearly illustrate the advantages of Chengli’s customized solution, the table below compares standard sewer cleaning trucks against Chengli’s delivered CLW5040TQYD6 solution (based on publicly available tender documents and Chengli’s product database): Comparison Item Market Standard Configuration Chengli Custom Solution (CLW5040TQYD6) Corrosion Protection Conventional paint; salt-spray resistance: 300 hours Hot-dip galvanizing + epoxy primer; salt-spray resistance: 1,000+ hours Sealing Material Standard chloroprene rubber; service life: 1–2 years Imported nitrile rubber + dust covers; service life: 3–5 years Hydraulic System Single gear pump; no oil cooler Dual-gear pump + oil cooler; supports 8-hour continuous oper