Pressure Seal Tilting Disc Check Valve - Knowledge

A pressure seal tilting disc check valve is two independent decisions sold as one product: a disc that pivots on a shaft set close to its own centre of mass, and a cover held shut by line pressure rather than by studs. A non-return valve high pressure service is therefore two problems in one body: the disc decides the first 200 milliseconds after a pump trips, and the cover decides the next ten years. Two numbers that decide whether the valve fits are, unusually, missing from every product standard: the face-to-face length, because ASME B16.10 has no tilting disc column, and the head loss, because it follows a disc angle that no standard fixes.

Design Standard

Basic Design	BS 1868 / ASME B16.34
Face to Face/End to End	ASME B16.10
Flanged End	ASME B16.5
Buttwelding End	ASME B16.25
Pressure–temperature Rating	ASME B16.34
Inspection and Test	API 598

Design Features

1. Segmental thrust ring absorb al the thrust applied by the internal pressure.
2. Thrust rings to prevent deformation of the gaskets.
3. Easy to operate and maintain on-line. The rotating center pin is close to the center of gravity, so there is no slide between disc seal cone surface and seat, and water hammer is greatly reduced.
4. Conical sealing surface faces to the center automatically, so it can be applied in vertical pipe, which the medium flow direction from bottom to the top.
5. Quickly open and close, to effectively prevent medium backflow and reduce the water hammer.

Pressure Seal Tilting Disc Check Valve Drawing

Material of Construction

Part No.	Part Name	Carbon Steel	High Temperature
1	Body	ASTM A216 Gr.WCB	ASTM A217 Gr.C12A
2	Seat	ASTM A105+HF*	ASTM A182 F91+HF*
3	Disc	ASTM A216 Gr.WCB+HF*	ASTM A217 Gr.C12A+HF*
4	Pin	ASTM A182 F6a	ASTM A182 F6a
5	Bonnet	ASTM A105	ASTM A182 F91
6	Seal Ring	ASTM A276 Type 304L	ASTM A276 Type 304L
7	Thrust Ring	ASTM A182 F6a	ASTM A182 F6a
8	Segmental Thrust Ring	ASTM A182 F6a	ASTM A182 F6a
9	Support Plate	ASTM A182 F6a	ASTM A182 F6a
10	Stud	ASTM A193 Gr.B7	ASTM A193 Gr.B16
11	Nut	ASTM A194 Gr.2H	ASTM A194 Gr.7
12	Lifting Lug	Steel	Steel
13	Bushing	ASTM A182 F6a	ASTM A182 F6a
14	Packing	Graphite	Graphite
15	Plug Screw	ASTM A29 Gr.1035	ASTM A182 F6a
16	Plug Screw Washer	ASTM A276 Type 316	ASTM A276 Type 316

*HF: Hard-faced with stellite 6 or equivalent.

Dimension & Weight

CLASS 600

Size		L		L1		L2		H		Approx Weight(WB)
DN	NPS	mm	in	mm	in	mm	in	mm	in	kg	lb
50	2	178	7.00	292	11.50	295	11.62	165	6.50	22	49
80	3	254	10.00	356	14.00	359	14.12	185	7.28	24	53
100	4	305	12.00	432	17.00	435	17.12	227	8.94	45	99
150	6	457	18.00	559	22.00	562	22.12	298	11.73	110	243
200	8	584	23.00	660	26.00	663	26.12	332	13.07	209	461
250	10	711	28.00	787	31.00	790	31.12	383	15.08	499	1100
300	12	813	32.00	838	33.00	841	33.12	410	16.14	787	1735
350	14	889	35.00	889	35.00	892	35.12	451	17.76	1073	2366
400	16	991	39.00	991	39.00	994	39.12	511	20.12	1356	2989
450	18	1092	43.00	1092	43.00	1095	43.12	552	21.73	1642	3620
500	20	1194	47.00	1194	47.00	1200	47.25	591	23.27	1927	4248
600	24	1397	55.00	1397	55.00	1407	55.38	645	25.39	2667	5880

CLASS 900

Size		L		L1		L2		H		Approx Weight(WB)
DN	NPS	mm	in	mm	in	mm	in	mm	in	kg	lb
50	2	216	8.50	368	14.50	371	14.62	147	5.79	28	62
80	3	305	12.00	381	15.00	384	15.12	198	7.80	39	86
100	4	356	14.00	457	18.00	460	18.12	244	9.61	95	209
150	6	508	20.00	610	24.00	613	24.12	307	12.09	197	434
200	8	660	26.00	737	29.00	740	29.12	342	13.46	229	505
250	10	787	31.00	838	33.00	841	33.12	412	16.22	526	1160
300	12	914	36.00	965	38.00	968	38.12	460	18.11	823	1814
350	14	991	39.00	1016	40.00	1026	40.38	495	19.49	1120	2469
400	16	1092	43.00	1130	44.50	1140	44.88	556	21.89	1417	3124
450	18	1219	48.00	1219	48.00	1232	48.50	581	22.87	1714	3779
500	20	1321	52.00	1321	52.00	1334	52.50	619	24.37	2011	4433
600	24	1549	61.00	1549	61.00	1568	61.75	695	27.36	2948	6499

CLASS 1500

Size		L		L1		L2		H		Approx Weight(WB)
DN	NPS	mm	in	mm	in	mm	in	mm	in	kg	lb
50	2	216	8.50	368	14.50	371	14.62	188	7.40	37	82
80	3	305	12.00	470	18.50	473	18.62	194	7.64	45	99
100	4	406	16.00	546	21.50	549	21.62	244	9.61	88	193
150	6	559	22.00	705	27.75	711	28.00	344	13.54	209	461
200	8	711	28.00	832	32.75	842	33.13	412	16.22	405	893
250	10	864	34.00	991	39.00	1000	39.38	478	18.82	638	1407
300	12	991	39.00	1130	44.49	1146	45.12	529	20.83	898	1980
350	14	1067	42.00	1257	49.49	1277	50.28	582	22.91	1519	3349
400	16	1194	47.00	1384	54.50	1407	55.38	634	24.96	2141	4720
450	18	1537	60.50	1537	60.50	1559	61.38	689	27.13	2483	5474
500	20	1664	65.50	1664	65.50	1686	66.38	742	29.21	2948	6499
600	24	1943	76.50	1943	76.50	1972	77.62	786	30.94	4036	8898

CLASS 2500

Size		L		L1		L2		H		Approx Weight(WB)
DN	NPS	mm	in	mm	in	mm	in	mm	in	kg	lb
50	2	279	11.00	451	17.75	454	17.87	190	7.48	40	88
80	3	368	14.50	578	22.75	584	23.00	213	8.39	57	126
100	4	457	18.00	673	26.50	683	26.88	242	9.53	96	212
150	6	610	24.00	914	36.00	927	36.50	347	13.66	241	531
200	8	762	30.00	1022	40.25	1038	40.87	415	16.34	454	1001
250	10	914	36.00	1270	50.00	1292	50.88	491	19.33	775	1709
300	12	1041	41.00	1422	56.00	1445	56.88	557	21.93	1241	2736

Valve Factory

Request a Quotation

FAQ

What is a tilting disc check valve?

A check valve whose single disc swings open on a shaft set close to its own centre of mass, so the disc lifts away from a seat inclined to the flow instead of hinging from the top of the bore. Because the shaft is near the centre, the mass moment of inertia about that shaft is small and the disc covers its whole stroke quickly. The same geometry puts the shaft and its bushings inside the flow path.

How does a tilting disc check valve work?

Forward flow pushes the disc off an inclined seat and rotates it about 40 degrees to a stop lug in the body, where it sits clear of the main stream. When the flow decelerates the disc falls back through a short arc, and the last few millimetres are closed by the reverse differential acting on the disc face. The valve has no stem, no actuator and no packing, so nothing outside the pipe can hold it open or shut.

Tilting disc vs swing check: which should I choose?

Choose by what is in the pipe and how fast the flow reverses. A swing check keeps its hinge outside the flow and tolerates dirty service, but the disc edge travels about 1.35 times the bore, so it needs a long time to close. A tilting disc travels a short arc and closes sooner, at the cost of a shaft in the stream. For clean water, steam or hydrocarbon above 1.4 m/s, the tilting disc wins on closure. For sludge, fibre or slurry, the swing check is the only one of the two that survives.

What is the correct tilting disc check valve installation position?

Horizontal installation means a horizontal pipe with the pivot shaft horizontal; vertical upflow means a vertical pipe with the flow going up. Never vertical down-flow: the disc then hangs on its seat and the valve looks correct from outside while passing reverse flow. The shaft must stay horizontal in both layouts so that gravity assists closure; rotating the valve about the pipe axis to put the shaft vertical removes that assistance and adds the disc weight to the bushing load.

Pressure seal vs bolted bonnet: which do I need?

On a check valve, choose the pressure seal bonnet for consistency with the rest of a Class 900 and above piping specification, or where the cover is too heavy for a stud circle. A bolted bonnet with a spiral wound gasket seals the same pressure, and it opens in minutes with hand tools. The pressure seal joint seals better as pressure rises but needs a new gasket ring every time it is opened, and the ring is matched to that body's taper, not to its size and class.

What is the pressure drop of a tilting disc check valve?

It depends on the disc angle, which no standard fixes. Crane TP-410 separates two tilting disc geometries by an angle alpha and gives a loss coefficient of 1.689 at 15 degrees and 0.5629 at 5 degrees. Back-calculated against the friction factor used in the same table, those are L/D 120 and L/D 40, against 100 for a swing check and L/D 600 for a lift check. At NPS 6 and 2 m/s the two tilting disc geometries differ by 0.023 bar and about 670 kWh a year.

Can tilting disc be used in wastewater?

Not in raw sewage or anything carrying fibre, wipes or grit. The pivot shaft and its bushings sit in the flow path, so solids wrap the shaft and stop the disc reaching its stop lug. The disc then sits half open, flutters, and wears the bushings oval. Water treatment plants put the shaft out of the stream by using a different closure for influent duty and reserve the tilting disc for cleaner effluent.

Are you a tilting disc check valve manufacturer or a trader?

We are a trading company with our own machining and assembly, and the castings come from nominated foundries whose heat numbers appear on the certificate. We do not claim an API Monogram and we do not print one on the body. What we do control is which foundry pours which class, which shop machines the seat, and where each test happens, and we will name all three for your order before you place it.

Can you supply as a pressure seal check valve supplier against a project specification?

Yes, and the useful part is telling you where the specification cannot be met by any supplier. A line item reading pressure seal tilting disc check valve to API 594 Type B cannot be certified, because API 594 Type B is defined as a bolted cover swing check. Write the body to EN 16767 and ASME B16.34, the bonnet to MSS SP-144, and the length as a number in millimetres.

What does a tilting disc check valve price depend on?

Four things move it more than size: the pressure class, because wall thickness and the pressure seal split ring scale with it; the body material, with WC6 and CF8M well above WCB; whether the seat ring is renewable or integral; and whether the pivot assembly is a weld-in cartridge. A Class 2500 NPS 12 valve is not a scaled-up Class 600 NPS 6 valve, and quoting it as one is how delivery dates slip.

What tilting disc check valve dimensions must I fix before ordering?

Three, and only one of them is in a standard. Fix the face-to-face in millimetres, because ASME B16.10 has no tilting disc column and the number must come from your spool drawing or from a nominated column. Fix the end connection and facing, including whether Class 2500 flanges are within ASME B16.5 at your size. Fix the disc angle or accept the manufacturer's, since it sets the head loss you will live with.

What pressure seal check valve maintenance is required?

Two routines. Grease the pivot bushings on the interval the manual gives, often monthly on large valves, because dry bushings wear oval and a disc that sits off its stop lug flutters. Then inspect the seat and bushings, which means opening the cover, which on a pressure seal body means a new gasket ring. Replace the pivot pin and both bushings as a set once the bore is oval beyond about 0.2 mm; a new pin in a worn bore re-wears in weeks.

How is it tested and what documents come with it?

Shell at 1.5 times the 38 °C rating and seat at 1.1 times, to API 598, with the metal seat allowance of 3 x NPS cm3/min of water recorded per serial number. Documents are EN 10204 3.1 as standard and 3.2 when an inspector witnesses, a dimensional record including the face-to-face actually measured, positive material identification on alloy and stainless bodies, and API 6FA fire test evidence if you ask for it rather than API 607.