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.

Test pressure	Nominal pressure (MPa)
Test pressure	1.6	2.5	4.0	6.4	10.0
Shell test	2.4	3.8	6.0	9.6	15.0
Seal test	1.8	2.8	4.4	7.1	11.0
Body material	WCB(C)	CF8(P)	CF 8M (R)	WC6	WC9
Operating temperature	≤ 425	≤ 100	≤ 100	≤ 550	≤ 550
Applicable media	Water, steam, oil	Nitric acid	Acetic acid	Steam	Steam

National standard (GB) PN1.6MPa
DN	L	D	D1	D2	b	Z-фd
15	130	95	65	45	14	4-ф14
20	150	105	75	55	14	4-ф14
25	160	115	85	65	14	4-ф14
32	180	135	100	78	16	4-ф18
40	200	145	110	85	16	4-ф18
50	230	160	125	100	16	4-ф18
65	290	180	145	120	18	4-ф18
80	310	195	160	135	20	8-ф18
100	350	215	180	155	20	8-ф18
125	400	245	210	185	22	8-ф18
150	480	280	240	210	24	8-ф23
200	550	335	295	265	26	12-ф23
250	650	405	355	320	30	12-ф25
300	750	460	410	375	30	12-ф25
350	850	520	470	435	34	16-ф25
400	950	580	525	485	36	16-ф30
National standard (GB) PN2.5MPa
DN	L	D	D1	D2	b	Z-фd
15	130	95	65	45	16	4-ф14
20	150	105	75	55	16	4-ф14
25	160	115	85	65	16	4-ф14
32	180	135	100	78	16	4-ф18
40	200	145	110	88	18	4-ф18
50	230	160	125	100	20	4-ф18
65	290	180	145	120	22	4-ф18
80	310	195	160	135	22	8-ф18
100	350	230	190	160	24	8-ф23
125	400	270	220	188	28	8-ф25
150	480	300	250	218	30	8-ф25
200	550	360	310	278	34	12-ф25
250	730	425	370	332	36	12-ф30
300	850	485	430	390	40	16-ф30
350	850	550	490	448	44	16-ф30
National standard (GB) PN4.0MPa
DN	L	D	D1	D2	b	Z-фd
15	130	95	65	45	16	4-ф14
20	150	105	75	55	16	4-ф14
25	160	115	85	65	16	4-ф14
32	180	135	100	78	16	4-ф18
40	200	145	110	88	18	4-ф18
50	230	160	125	100	20	4-ф18
65	290	180	145	120	22	4-ф18
80	310	195	160	135	22	8-ф18
100	350	230	190	160	24	8-ф23
125	400	275	220	188	28	8-ф25
150	480	300	250	218	30	8-ф25
200	550	375	320	282	38	12-ф30

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