Question 1

What valves are used in water conservancy projects?

Accepted Answer

Water conservancy projects use a variety of valves depending on the application: (1) Large-diameter butterfly valves for water mains and penstock isolation (up to DN4000); (2) Gate valves (sluice gate valves) for water treatment plant channels and penstocks; (3) Check valves on pump discharge lines to prevent reverse flow and water hammer; (4) Hydraulic control valves for automatic pressure, flow, and level control in distribution networks; (5) Air release/vacuum valves for air pocket prevention and pipeline surge protection; (6) Flow control valves for precise flow regulation in irrigation canals and water diversion tunnels.

Question 2

What is a hydraulic control valve?

Accepted Answer

A hydraulic control valve is a pilot-operated, diaphragm-actuated valve that uses the line pressure of the water itself (hydraulic power) to operate — no external power source required. It can perform multiple functions: pressure reducing (maintaining constant downstream pressure), pressure sustaining/relief (protecting upstream pressure), float control (maintaining tank/reservoir level), flow control (limiting maximum flow rate), pump control (surge protection on pump start/stop), and solenoid override (remote on/off). Hydraulic control valves are widely used in municipal water distribution, irrigation networks, and fire protection systems.

Question 3

Why are air release valves needed in water pipelines?

Accepted Answer

Air release valves (also called air/vacuum valves) serve three critical functions in water pipelines: (1) Air release — automatically venting accumulated air pockets that form at high points, preventing flow restriction and energy loss; (2) Vacuum breaking — admitting air during pipeline draining or pump trips to prevent vacuum collapse of the pipe; (3) Surge protection — controlled air release during filling to prevent hydraulic surge. Without air valves, air pockets reduce pipeline capacity by 10-30%, increase pumping costs, and can cause pressure surges that damage pipes and fittings.

Question 4

What is the largest valve size TANGGONG can manufacture for water projects?

Accepted Answer

TANGGONG can manufacture butterfly valves up to DN4000 (4 meters / 160 inches) in diameter for water conservancy projects. These large-diameter butterfly valves are typically double-flanged, rubber or metal seated, and actuated by electric or hydraulic operators. They are used for water main isolation, penstock shutoff, and pump station suction/discharge in municipal water supply systems, irrigation projects, and hydropower stations. Custom sizes above DN4000 can be evaluated on a project-specific basis.

Question 5

What standards apply to water conservancy valves?

Accepted Answer

Key standards for water conservancy valves include: AWWA C504 (rubber-seated butterfly valves), AWWA C509/C515 (resilient-seated gate valves), AWWA C508 (swing check valves), AWWA C512 (air release, air/vacuum, and combination air valves), EN 1074 (valves for water supply — fitness for purpose requirements), EN 593 (industrial butterfly valves), GB/T 12238 (butterfly valves — Chinese national standard), and ISO 5752 (face-to-face dimensions for metal valves). TANGGONG manufactures to AWWA, EN, GB, and ISO standards per project requirements.

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