Name: TANGGONG Industrial Check Valve Series
Brand: TANGGONG VALVE GROUP
Availability: InStock
Rating: 4.8 (127 reviews)

Question 1

What is the difference between a swing check valve and a wafer check valve?

Accepted Answer

A swing check valve uses a hinged disc that swings fully open with forward flow and closes by gravity and reverse flow — suitable for larger diameters (DN50–DN1200), lower flow velocities, and applications where minimal pressure drop is critical. A wafer check valve is a compact, spring-loaded dual-plate design that fits between flanges — it is significantly lighter and shorter than swing check types, closes faster to reduce water hammer, and is ideal for space-constrained installations in smaller to medium diameters (DN50–DN600).

Question 2

Where are check valves used?

Accepted Answer

Check valves (non-return valves) are used wherever backflow must be prevented to protect upstream equipment. Common applications include: pump discharge lines (preventing reverse flow damage), compressor discharge piping, boiler feedwater systems, steam condensate return, water distribution network backflow prevention, fire protection risers, pipeline cross-connection prevention, tank fill systems, heat exchanger bypass circuits, and chemical injection quills. Check valves are automatic safety devices requiring no external actuation or operator intervention.

Question 3

Can a check valve be installed vertically?

Accepted Answer

Yes, certain check valve types can be installed in vertical (upward flow) pipelines. Swing check valves can operate vertically when forward flow is upward — the disc opens by flow pressure and closes by gravity. Piston (spring-loaded) check valves are ideal for vertical installation as the spring assists closure regardless of gravity direction. Wafer and dual plate check valves with springs also function in any orientation. Ball check valves operate in vertical lines with upward flow using gravity for closure. Always specify installation orientation when ordering so TANGGONG can configure the appropriate spring settings and verify performance.

Question 4

What causes check valve water hammer and how to prevent it?

Accepted Answer

Check valve water hammer (hydraulic shock) occurs when the valve disc closes too slowly and a sudden reversal of flow slams the disc against the seat, creating a pressure surge that travels through the piping system. Prevention methods include: (1) using spring-loaded wafer or dual plate check valves that close before reverse flow fully develops; (2) selecting piston check valves with short stroke and spring-assisted closure; (3) installing external dampeners or dashpots on larger swing check valves; (4) properly sizing the check valve so that normal operating velocity keeps the disc fully open without flutter. TANGGONG recommends dual plate wafer check valves with spring-loaded discs for applications susceptible to water hammer.

Question 5

What certifications do TANGGONG check valves have?

Accepted Answer

TANGGONG check valves are manufactured under ISO 9001:2015 quality management, certified to API 594 (wafer and dual plate check valves), API 6D (pipeline valves including swing check types), CE (EU Pressure Equipment Directive), TUV, and SGS. Testing is performed to API 598 and ISO 5208 standards for shell integrity and seat leakage. Material test certificates (EN 10204 3.1), NDE reports (RT, UT, PT, MT), and third-party inspection by Lloyd's, DNV, BV, or ABS are available for project requirements.

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