DN500 WCB Top Entry Eccentric Hemisphere Flanged Ball Valve (Handwheel Worm Gear Type)

Project managers in charge of large municipal water treatment plants and heavy industrial fluid pipelines often face tough problems when sourcing DN400-DN600 large bore shut-off valves. Conventional butterfly valves and side-mounted ball valves easily accumulate sludge and scale inside the cavity when delivering sewage, ore slurry and mixed impurity medium, leading to stuck operation and frequent seal failure. What’s more, most large-size valves need to be fully detached from the pipeline for maintenance, requiring complete medium drainage, which causes huge production suspension losses and raw material waste.This DN500 WCB top entry eccentric hemisphere valve solves these practical on-site troubles. Clients who installed this worm gear handwheel model on urban main sewage pipelines, mine slurry delivery mains, thermal power circulating water systems and chemical waste liquid trunk lines shared real operating experience. The top-entry structure allows maintenance crews to take out all internal hemisphere components just by opening the top bonnet, without cutting off or disassembling the whole valve from buried large pipelines. The eccentric knife-edge hemisphere automatically scrapes off sediment every 90-degree opening and closing stroke, effectively preventing scaling blockage. The matched large handwheel worm gear actuator delivers stable, labor-saving slow switching even for DN500 ultra-large bore pipelines. The bidirectional spring floating seat automatically compensates seal clearance after long-time abrasion, maintaining tight zero-leakage performance under fluctuating positive and reverse pressure.

This DN500 large bore top entry eccentric hemisphere flanged ball valve strictly implements a complete set of national industrial standards covering design, structural length, flange connection and factory bidirectional pressure testing, all specifications are accepted by third-party testing labs and global export customs authorities:  

Design & Manufacturing Standard: GB/T12237

• Valve Face-to-Face Structural Length Standard: GB/T12221

• Flange Connection Dimension Standard: JB/T79-2015, HG/T20592

• Shell & Bidirectional Seat Tightness Inspection Standard: GB/T26480Our factory owns integrated production lines including WCB carbon steel precision casting, heavy-duty CNC machining, anti-rust epoxy blue coating and full hydrostatic testing. Every finished DN500 eccentric hemisphere valve completes shell strength test and forward & reverse high-pressure sealing test before shipment. Complete WCB material certificates, bidirectional pressure test reports and full dimension drawings can be supplied for overseas municipal, mining, thermal power and chemical large project bidding and customs clearance filing.

1. Ultra-low pressure loss at full open, full straight-through self-cleaning flow channelWhen fully opened, pressure drop is close to zero. The unobstructed straight cavity carries automatic flushing function to avoid medium sediment and pipeline blockage.

2. Labor-saving worm gear handwheel operation, friction-free sealing surface rotationNo swinging internal components. Driven by eccentric mechanical force, the hemisphere only fully contacts the sealing seat at the final closing stroke. The ball surface rotates without scratch or friction against the sealing ring, and the worm gear reduces operation torque greatly for DN500 large size.

3. Knife-edge hemisphere self-cleaning & anti-scaling structureThe knife-shaped edge of the hemisphere forms wiping & shearing effect between ball and seat. While rotating, it automatically flushes sludge and impurities inside the valve cavity, no residue accumulates to cause scaling and jamming.

4. Bidirectional spring floating seat self-compensating sealing for long-time zero leakageUnder positive pressure: Eccentric force pushes the hemisphere tightly against the seat for reliable sealing.Under reverse pressure: Medium pressure pushes floating seat toward the ball, built-in spring automatically compensates clearance once sealing ring wears, stable bidirectional sealing under fluctuating pressure working conditions.

5. Suitable for high-flow high-speed medium, vibration-free & quiet runningThe hemisphere only occupies single side of valve cavity to form smooth straight flow path. Stable eccentric positioning structure eliminates vibration and noise under continuous high-speed medium flushing of large flow.

6. High Cv flow coefficient, lower overall pipeline system energy consumptionHemispherical ball core creates maximum Cv flow coefficient, cutting pipeline flow resistance and reducing long-term operation energy cost of heavy industrial large-bore fluid conveying system.

7. Top-entry maintenance design, no need to remove whole valve from large pipelineBall assembly and bracket are installed from valve top. For maintenance, only open the top bonnet and lift out ball & seat parts, no need to separate the entire DN500 valve from buried trunk pipelines, cutting excavation and pipeline disassembly construction cost largely.

8. Medium interception during overhaul, emergency repair without full pipeline shutdown  

• The valve can lock off medium inside pipeline during maintenance, avoiding leakage and waste of raw fluid, eliminating repeated medium drainage work before overhaul.

• For emergency rush repair scenarios, quickly seal the top opening after taking out ball assembly, pipeline can resume medium delivery immediately, minimizing production loss caused by valve overhaul. 

1. Municipal Large-Diameter Sewage & Reclaimed Water Trunk PipelinesMain shut-off valve for urban DN500 buried sewage mains, sludge conveying trunk lines and reclaimed water reuse network. Self-cleaning anti-scaling structure solves the scaling failure defect of ordinary butterfly valves under long-term sewage medium operation.

2. Mining Ore Slurry Conveying Pipeline SystemsLarge bore shut-off equipment for mine raw ore slurry, tailing mixed fluid delivery mains. Hard alloy surfacing hemisphere resists abrasive particle impact, top-entry design reduces mine pipeline overhaul construction volume.

3. Thermal Power Plant Circulating Cooling Water & Steam Main PipelinesMain switch valve for boiler auxiliary saturated steam and factory large circulating cooling water trunk lines. WCB carbon steel body stably withstands high temperature up to 425℃, flexible graphite packing prevents high-temperature steam ejection leakage. 4. Heavy Chemical Factory Waste Liquid & Slurry Delivery Trunk LinesShut-off control for dilute acid, dilute alkali, chemical mixed waste liquid, viscous chemical slurry large pipelines. Bidirectional self-compensating floating seat adapts variable pressure continuous chemical production conditions.

5. Underground Buried Large Industrial Pipeline NetworksDN500 buried heavy industry water supply & waste liquid trunk valve, top-entry maintenance avoids large-scale road excavation for municipal and factory pipeline overhaul.

6. Large Scale Central Heating Municipal Steam Pipe NetworksCity central heating main pipeline cut-off valve, worm gear handwheel realizes stable slow opening and closing for ultra-large diameter heating pipelines.

7. Metallurgical Factory High-Flow Circulating Water SystemsMetallurgical workshop large circulating cooling water main shut-off valve, stable vibration-free operation under long-term high-speed water flow impact.

8. River Water Intake & Large Water Conservancy Project PipelinesWater intake trunk shut-off valve for reservoirs and river water diversion projects, large Cv flow coefficient meets ultra-large volume water delivery demand.