Full Bore Straight Ball Valve for Long-Distance Water Transmission Pipelines
Full bore straight ball valve eliminates pressure drop in large-diameter water pipelines. Used in China’s South-to-North Water Diversion Project. DN2800, low head loss, piggable design. Inquiry now.
Description
In large‑scale water diversion projects and long‑distance water transmission pipelines, local head loss of valves under fully‑open conditions directly influences pump station head design and annual power consumption. The full bore straight ball valve features an internal bore diameter identical to that of the pipeline. When fluid passes through, flow‑velocity profiles remain undisturbed without additional contraction‑induced turbulence, fundamentally eliminating local resistance bottlenecks commonly seen in conventional valves.
Functions and Working Principle
The core purpose of the straight ball valve is trunk‑line shut‑off and isolation for reliable water cut‑off during maintenance, emergency events or operational dispatching. Its ball incorporates a straight circular through‑bore and opens/closes via 90‑degree rotation. In the fully‑open position, the ball passage aligns perfectly with the pipeline axis; in the fully‑closed position, the solid segment of the ball rotates into the flow path to achieve shut‑off. Thanks to its full‑bore geometry, an opened valve behaves hydraulically like a straight pipe segment of equal nominal size with an extremely low flow‑resistance coefficient.
Materials and Specifications
Tailored for large‑diameter, low‑pressure and long‑service‑life requirements of water conveyance projects, this valve series adopts the following design configurations:
- Body material: Ductile iron (QT450‑10 / GGG40), balancing mechanical strength and corrosion resistance for buried and above‑ground installation.
- Ball material: 304L stainless steel or carbon‑steel substrate with nickel‑chromium alloy coating. Hardened surface treatment delivers erosion resistance against sediment‑laden flow.
- Seat material: Reinforced PTFE or nitrile butadiene rubber (NBR), suitable for drinking‑water and raw‑water services.
- End connection: Double‑flanged (RF flange face complying with EN 1092 / ASME B16.47) or fully‑welded type for buried applications.
- Operation: Manual gearbox / electric actuator / hydro‑pneumatic actuator for remote dispatching and control.
- Design standards: GB/T 19672 / ISO 17292 / API 6D (where applicable).
Main Technical Parameters of Full Bore Straight Ball Valve
| Parameter | Technical Specification |
|---|---|
| Nominal Diameter (DN) | DN200 – DN3000 (8″ – 120″) |
| Pressure Rating | PN6 – PN25 / Class 150 |
| Body Material | Ductile Iron (QT450‑10) / Carbon‑Steel WCB / Stainless Steel |
| Ball Material | 304L / 316L / Coated Carbon Steel |
| Seat Material | PTFE / NBR / Reinforced Nylon |
| End Connection | Flanged (RF) / Fully‑Welded / Mechanical Joint |
| Operation Type | Gearbox / Electric / Hydro‑Pneumatic / Hydraulic |
| Design Standards | GB/T 19672 / ISO 17292 / AWWA C507 |
| Bore Type | Full Bore, inner bore ≥ pipeline inner diameter |
| Pigging Capability | Piggable |
| Fully‑Open Pressure‑Loss Coefficient (K‑value) | ≤ 0.05 |
Application Scenarios
- Long‑distance water‑diversion trunk‑line projects (South‑to‑North Water Diversion, Han‑to‑Wei Water Transfer, etc.)
- Raw‑water transmission pipelines for municipal water supply
- Circulating cooling‑water systems of thermal‑power and nuclear‑power plants
- Large‑scale irrigation canal networks and pump‑station inlet‑outlet lines
- Main pipelines for industrial circulating‑water systems
Typical Application Case
In the diversion‑outlet project of the Hebei section on the Middle Route of the South‑to‑North Water Diversion Project operated by China South‑to‑North Water Diversion Group Co., Ltd., DN2800 full‑bore straight ball valves were selected to satisfy strict head‑loss control for gravity‑driven long‑distance water conveyance. These valves are installed at outlets of booster pump stations and gravity‑flow diversion points. Field measurements show their fully‑open head loss is merely one‑third of that of butterfly valves of the same size. Approved by the Administration Bureau for Planning, Design and Management of the South‑to‑North Water Diversion under the Ministry of Water Resources, the full‑bore solution guarantees stable attainment of designed water‑supply levels for end‑users in Beijing and Tianjin.
Since full commissioning in 2021, continuous monitoring across two complete water‑supply cycles has revealed a deviation below 2 % between measured fully‑open pressure loss and design values. The valves operate flexibly with dependable sealing performance, providing critical technical references for key‑equipment selection of mega‑scale inter‑basin water‑transfer projects in China.
Technical Selection Guidelines
Three key points deserve careful verification when specifying full‑bore straight ball valves:
- Confirm that the nominal diameter (DN) matches the inner diameter of upstream piping, avoiding effective bore reduction caused by mismatched flange standards.
- Verify operating torque compatibility against the rated output of field actuators (electric / hydro‑pneumatic).
- If periodic pigging is planned for the pipeline, validate whether valve construction (fully‑welded or flanged) allows smooth pig passage, and require submission of pigging‑capability test reports.
