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.

PN	1.0MPa	1.6MPa	2.5MPa
Body testing pressure	1.5MPa	2.4MPa	3.75MPa
Sealing testing pressure	1.1MPa	1.76MPa	2.75MPa
Working temperature	≤80℃	≤80℃	≤80℃
Minimum motion pressure	P1≥0.07MPa	P1≥0.07MPa	P1≥0.07MPa
Voltage of alter‑mating current	AC 220V	AC 220V	AC 220V
Solenoid valve voltage of direct current	DC 24V	DC 24V	DC 24V
Applicable medium	Water	Water	Water

DN(mm)	L	H	H1	W	W1	F
40	210	395	278	240	155	170
50	210	395	278	240	155	170
65	240	405	298	255	165	180
80	285	430	315	280	175	210
100	360	510	350	332	195	275
125	400	560	365	375	220	310
150	455	585	420	408	230	355
200	585	675	450	485	255	460
250	780	730	470	550	300	500
300	800	760	490	630	340	580
350	860	840	526	735	415	640
400	960	910	570	788	430	715
Piston‑450	1075	1070	610	850	460	780
Piston‑500	1075	1135	665	905	490	830
Piston‑600	1230	1270	725	970	530	920
Piston‑700	1650	1460	865	1050	560	980
Piston‑800	1750	1640	975	1135	610	1050

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