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Introduction

Double block & bleed valve (DBBV) is a non-lubricated, resilient seal, plug-type valve which has a mechanical means of freeing the plug before it is rotated from the closed to the open position.

In opening the valve, the plug is raised, thus retracting the seating segments or slips through their tapered dovetail connections. Only after the slips are fully retracted from the body seat is the plug rotated to the open position.

Conversely, in closing the valve, the plug and slips are rotated freely, with no seal-to-body contact until the slips are positioned over the ports.

Then the plug is driven down between the slips and the tapered surfaces wedge out the slips for a positive upstream as well as downstream shut-off.

The small DBB general plug valve is handwheel operated, and require up to 3 turns to open or close. Up to 2 3/4 turns expand or retract the slips, while turn rotates the plug. Large valves operate in a similar manner, except that they have enclosed weather-proof worm gearing.

At the top of the valve, a position indicator flag shows the exact plug position. It appears in line with the flow when the valve is open and perpendicular to the flow when the valve is closed.

Since DBBV hold bubble-tight, for ease of opening in liquid service, it is important to prevent trapped body pressure from exceeding the working pressure of the valve.

Therefore, a relief system is required to prevent pressure buildup in the body cavity.

For maximum upstream sealing, do not back off the hand wheel.
Warning: Do not over torque by using cheater bars.

Pressure Test

ASME Class	150		300	600	900	Result
Shell Test Pressure (Valve Open)	(Pisg) (kg/cm2)	500 35	1200 85	2250 158	3350 235	No Leakage Permitted
Seat Test Pressure	(Pisg)	300	800	1600	2400	Test upstream & downstream
(Valve Closed)	(kg/cm2)	21	56	113	168	Seats. No leakage permitted
Supplementary (API 598) Air Seat Test Pressure	(Pisg)	80	80	80	80	Test upstream & downstream
(Valve Closed)	(kg/cm2)	6	6	6	6	Seats. No leakage permitted

Structure of Short Pattern with Handle Wheel

1	2	3	4	5	6	7	8	9	10
Body	Cover	Bearing	Drain valve	O-ring	Spiral Wounded Gasket	Stud	Nut	Plug	Disc
11	12	13	14	15	16	17	18	19	20
Upper Cover	Upper Bearing	Seal ring	O-ring	Packing	Packing Gland	Yoke	Slide Bushing	Stem	Hand Wheel

Structure of Short Pattern with Gear

1	2	3	4	5	6	7	8	9	10
Body	Lower Cover	Non-lubricated bearing	Drain Valve	O-ring	FS Gasket	Stud	Nut	Plug	Disc
11	12	13	14	15	16	17	18	19	20
Upper Cover	Stem	FS Packing	Pin	Inner Hex Screw	Block	Stud	Nut	Driving device	Seal Ring

Structure of Reduced Bore Type with Gear

1	2	3	4	5	6	7	8	9	10
Body	Lower Cover	Non-lubricated bearing	Drain Valve	O-ring	FS Gasket	Stud	Nut	Plug	Disc
11	12	13	14	15	16	17	18	19	20
Upper Cover	Stem	FS Packing	Pin	Inner Hex Screw	Packing Gland	Block	Stud	Nut	Handwheel
21	22	23	24	25	26	27	28	29	30
Seal Ring	Guiding Bush	Shaft Bushing	Indicating Arm	Set Screw	Pointer	Nut	Stud	Handwheel	Pin
31	32	33	34	35
Seal Ring	Inner Hex Screw	FS Packing	Bearing	Drain Valve

Structure of Full Bore Type with Gear

1	2	3	4	5	6	7	8	9	10
Body	Lower Cover	Non-lubricated Bearing	Drain Valve	O-ring	FS Gasket	Stud	Nut	Plug	Disc
11	12	13	14	15	16	17	18	19	20
Upper Cover	Stem	FS Packing	Pin	Inner Hex Screw	Emgency seal device	Plug	Bolt	Nut	Driving Device
21	22	23	24	25	26	27	28	29	30
Seal Ring	Guiding Bush	Bearing	Indicating Arm	Set Screw	Pointer	Nut	Bolt	Hand Wheel	Pin
31	32	33	34	35
Inner Hex Screw	Inner Hex Bolt	FS Packing	Bearing	Drain Valve

Structure of Gear

NO.	Name
1	Yoke
2	Driving Stem
3	Driving Bushing
4	Worm Gear
5	Gear Stem
6	Box
7	Bearing Seat
8	Box Cover
9	Indicating Arm
10	HW
11	Lever
12	End cover
13	Gasket
14	Lockable Nut
15	Locking Nose
16	Lock Pad
17	Cover Cap
18	Nut
19	Stud
20	Bolt
21	Bolt
22	Lock screw
23	Bolt
24	Bolt
25	O-ring
26	O-ring
27	O-ring
28	O-ring
29	O-ring
30	Normal Key
31	Normal Key
32	Shaft Washer
33	Oil Cup
34	Bearing
35	Bearing

Materials

Number	Name	Material
1	Body	Casting steel ASTM A216 WCB, body inside Cr plated	Casting steel ASTM A352 LCB, body inside Cr plated	Casting steel ASTM A351 Cf8
2	Upper cover	Forged steel ASTM A105	Forged steel ASTM A105	Forged steel ASTM A182 F304
3	Lower corer	Casting steel ASTM A216 WCB	Casting steel ASTM A352 LCB	Casting steel ASTM A351 CF8
4	Stem	ASTM A182 F6a	ASTM A182 F6a	ASTM A182 F6a
5	Plug	Casting steel ASTM A216 WCB, surface ENP	Casting steel ASTM A352 LCB, surface ENP	Casting steel ASTM A351 Cf8
6	Disc	A536 65-45-12	A536 65-45-12	Casting steel ASTM A351 Cf8
7	Seal ring	Viton	Viton	Viton
8	Packing	Expanded graphite	Expanded graphite	Expanded graphite
9	O-ring	Viton	Viton	Viton
10	Stud	ASTM A 193 B7	ASTM A 193 B7	ASTM A 193 B8
11	Nut	ASTM A 194 2H	ASTM A 194 2H	ASTM A 194 8

Dimension of Short Pattern with Handwheel

Class	NPS	A	d	g	c	o	T	E	N-ΦD	H	H1	G	Wt	Cv
150	2	178	50	92	120.7	150	14.3	2	4-19	470	135	250	26	190
	3	203	76	127	152.4	190	17.5	2	4-19	517	159	300	34	254
	4	229	100	157.2	190.5	230	22.3	2	8-19	573	185	400	72	582
	6	267	150	215.9	241.3	280	23.9	2	8-22.5	712	215	450	107	1360
	8	292	201	269.9	298.5	345	27	2	8-22.5	760	288	500	210	2250
300	2	216	50	92	127	165	20.7	2	8-19	470	135	250	30	201
	3	283	76	127	168.3	210	27	2	8-22.5	530	159	350	43	265
	4	305	100	157.2	200	255	30.2	2	8-22.5	577	185	450	86	610
	6	403	150	215.9	269.9	320	35	2	12-22.5	712	220	550	180	1680
600	2	292	50	92	127	165	25.4	7	8-19	515	139	350	52	275
	3	356	76	127	168.3	210	31.8	7	8-22.5	530	159	400	77	290
	4	432	100	157.2	215.9	275	38.1	7	8-25.5	618	190	500	120	830

PN	DN	A	d	9	c	0	T	E	N-ΦD	H	H1	G	Wt	Cv
1.6	50	178	50	100	125	160	16	3	4-18	470	135	250	26	190
	80	203	76	135	160	195	20	3	8-18	517	159	300	34	254
	100	229	100	155	180	215	20	3	8-18	573	185	400	72	582
	150	267	150	210	240	280	24	3	8-22	712	215	450	107	1360
	200	292	201	265	295	335	26	3	12-23	760	288	500	210	2250
2.5	50	216	50	100	125	160	20	3	4-18	470	135	250	30	201
	80	283	76	135	160	195	22	3	8-18	530	159	350	43	265
	100	305	100	160	190	230	24	3	8-23	577	185	450	86	610
	150	403	150	218	250	300	30	3	8-25	712	220	550	180	1680
4.0	50	216	50	100	125	160	20	3	4-18	470	135	250	30	201
	80	283	76	135	160	195	22	3	8-18	530	159	350	43	265
	100	305	100	156	190	230	24	3	8-23	577	185	450	86	610
	150	403	150	218	250	300	30	3	8-25	712	220	550	180	1680
6.3	50	292	50	105	135	175	26	3	4-23	515	139	350	52	275
	80	356	76	140	170	210	30	3	8-23	530	159	400	77	290
	100	432	100	168	200	250	32	3	8-25	618	190	500	120	830
10	50	292	50	112	145	195	28	3	4-25	515	139	350	52	275
	80	356	76	148	180	230	34	3	8-25	530	159	400	77	290
	100	432	100	172	210	265	38	4.5	8-30	618	190	500	120	830

Dimension of Short Pattern with Gear

Class	NPS	A	d	g	c	o	T	E	N-ΦD	H	H1	H2	G	B	Wt	Cv
150	2	178	50	92	120.7	150	14.3	2	4-19	412	155	135	320	265	35	190
	3	203	76	127	152.4	190	17.5	2	4-19	429	155	159	320	265	48	254
	4	229	100	157.2	190.5	230	22.3	2	8-19	454	155	185	320	265	88	582
	6	267	150	215.9	241.3	280	23.9	2	8-22.5	575	185	215	460	330	126	1360
	8	292	201	269.9	298.5	345	27	2	8-22.5	656	185	288	460	330	246	2250
	10	330	252	323.8	362	405	28.6	2	12-25.5	734	185	333	460	330	289	3506
	12	356	303	381	431.8	485	30.2	2	12-25.5	752	194	350	460	372	458	3920
	14	381	334	412.8	476.3	535	33.4	2	12-28.5	808	194	385	460	372	560	5420
	16	406	385	469.9	539.8	595	35	2	16-28.5	847	210	417	500	400	775	6910
300	2	216	50	92	127	165	20.7	2	8-19	412	155	135	320	265	42	201
	3	283	76	127	168.3	210	27	2	8-22.5	429	155	159	320	265	55	265
	4	305	100	157.2	200	255	30.2	2	8-22.5	454	155	185	320	265	88	610
	6	403	150	215.9	269.9	320	35	2	12-22.5	575	185	215	460	330	185	1680
	8	419	201	269.9	330.2	380	39.7	2	12-25.5	656	185	288	460	330	362	2955
	10	457	252	323.8	387.4	445	46.1	2	16-28.5	734	185	333	460	330	462	3490
	12	502	303	381	450.8	520	49.3	2	16-32	752	194	350	460	372	736	4630
600	2	292	50	92	127	165	25.4	7	8-19	430	180	140	320	280	54	275
	3	356	76	127	168.3	210	31.8	7	8-22.5	445	180	159	320	280	80	290
	4	432	100	157.2	215.9	275	38.1	7	8-25.5	525	185	190	460	330	145	830
	6	559	150	215.9	292.1	355	47.7	7	12-28.5	655	194	249	460	372	360	2235
	8	660	201	269.9	349.2	420	55.6	7	12-32	760	210	310	500	400	574	3550

PN	DN	A	d	g	c	o	T	E	N-ΦD	H	H1	H2	G	B	Wt	Cv
1.6	50	178	50	100	125	160	16	3	4-18	412	155	135	320	265	35	190
	80	203	76	135	160	195	20	3	8-18	429	155	159	320	265	48	254
	100	229	100	155	180	215	20	3	8-18	454	155	185	320	265	88	582
	150	267	150	210	240	280	24	3	8-23	575	185	215	460	330	126	1360
	200	292	201	265	295	335	26	3	12-23	656	185	288	460	330	246	2250
	250	252	323.8	320	355	405	30	3	12-25	734	185	333	460	330	289	3506
	300	303	381	375	410	460	30	3	12-25	752	194	350	460	372	458	3920
	350	381	334	435	470	520	34	3	16-25	808	194	385	460	372	560	5420
	400	406	385	485	525	580	36	3	16-30	847	210	417	500	400	775	6910
2.5	50	216	50	100	125	160	20	3	4-18	412	155	135	320	265	42	201
	80	283	76	135	160	195	22	3	8-18	429	155	159	320	265	55	265
	100	305	100	160	190	230	24	3	8-23	454	155	185	320	265	88	610
	150	403	150	218	250	300	30	3	8-25	575	185	215	460	330	185	1680
	200	419	201	278	310	360	34	3	12-25	656	185	288	460	330	362	2955
	250	457	252	332	370	425	36	3	12-30	734	185	333	460	330	462	3490
	300	502	303	390	430	485	40	3	16-30	752	194	350	460	372	736	4630

PN	DN	A	d	g	c	o	T	E	N-ΦD	H	H1	H2	G	B	Wt	Cv
4.0 Female face	50	216	50	100	125	165	20	3	4-18	412	155	135	320	265	42	201
	80	283	76	135	160	195	22	3	8-18	429	155	159	320	265	55	265
	100	305	100	160	190	230	24	3	8-23	454	155	185	320	265	88	610
	150	403	150	218	250	300	30	3	8-25	575	185	215	460	330	185	1680
	200	419	201	282	320	375	38	3	12-30	656	185	288	460	330	362	2955
	250	457	252	345	385	445	42	3	12-34	734	185	333	460	330	462	3490
	300	502	303	409	450	510	46	4	16-34	752	194	350	460	372	736	4630
6.3 Female face	50	292	50	105	135	175	26	3	4-23	430	180	140	320	280	54	275
	80	356	76	140	170	210	30	3	8-23	445	180	159	320	280	80	290
	100	432	100	168	200	250	32	3	8-25	525	185	190	460	330	145	830
	150	559	150	240	280	345	38	3	8-34	655	194	249	460	372	360	2235
	200	660	201	300	345	415	44	3	12-34	760	210	310	500	400	574	3550
10 Female face	50	292	50	112	145	195	28	3	4-25	430	180	140	320	280	54	275
	80	356	76	148	180	230	34	3	8-25	445	180	159	320	280	80	290
	100	432	100	172	210	265	38	3	8-30	525	185	190	460	330	145	830
	150	559	150	250	290	350	46	3	12-34	655	194	249	460	372	360	2235
	200	660	201	312	360	430	54	3	12-41	760	210	310	500	400	574	3550

Dimension of Reduced Bore Type with Gear

Class	NPS	A	d	9	c	0	T	E	N-ΦD	H	H1	H2	G	B	Wt	Cv
150	18	864	436	533.4	577.9	635	38.1	2	16-32	923	210	393	600	463	1385	10740
	20	1016	487	584.2	635	700	41.3	2	20-32	958	210	436	600	463	1748	15460
	24	1219	589	692.2	749.3	815	46.1	2	20-35	1121	230	492	720	488	3405	23660
	30	1524	735	857.2	914.4	984	74.6	2	28-35	1269	250	590	860	770	7240	32500
	36	1981	874	1022	1085.8	1168	90.4	2	4-22	1500	250	730	860	815	11198	47300
300	14	762	334	412.8	514.4	585	52.4	2	20-32	860	210	338	600	463	1080	59200
	16	838	385	469.9	571.5	650	55.6	2	20-35	943	210	372	600	463	1440	9250
	18	914	436	533.4	628.6	710	58.8	2	24-35	1048	230	414	720	488	1895	11320
	20	990	487	584.2	685.8	775	62	2	24-35	1094	250	465	860	770	2220	16050
	24	1320	589	692.2	812.8	915	68.3	2	24-41	1148	250	519	860	770	4430	26590
	30	1651	735	857.2	997	1092	92	2	4-22	1435	250	590	860	815	8178	32990
600	10	787	252	323.8	431.8	510	63.5	7	16-35	919	230	336	720	488	1055	5020
	12	838	303	381	489	560	66.7	7	20-35	950	230	361	720	488	1375	9160
	14	889	334	412.8	527	605	69.9	7	20-38	964	230	375	720	488	2228	9400
	16	991	385	469.9	603.2	685	76.2	7	20-41	1132	250	413	860	770	2338	10800
	18	1029	436	533.4	654	745	82.6	7	20-44.5	1150	250	442	860	770	3566	13500
	20	1194	487	584.2	723.9	815	88.9	7	24-44.5	1336	250	479	860	815	4992	16260
	24	1397	589	692.2	838.2	940	101.6	7	24-51	1407	250	607	860	815	8154	2660
900	2	368	50	92	165.1	215	38.1	7	8-25.5	514	185	186	460	330	97	155
	3	381	76	127	190.5	240	38.1	7	8-25.5	582	185	171	460	330	126	245
	4	457	100	157.2	235	290	44.5	7	8-32	627	185	203	460	330	216	640
	6	610	150	215.9	317.5	380	55.6	7	12-32	710	194	270	500	372	530	2350
	8	737	201	269.9	393.7	470	63.5	7	12-38	908	230	303	720	488	618	4140
	10	838	252	323.8	469.9	545	69.9	7	16-38	1068	250	356	860	770	1956	5420
1500	2	368	50	124	165.1	215	38.1	7.9	8-25.5	592	185	190	460	330	97	155
	3	470	76	168	203.2	265	47.7	7.9	8-32	607	185	202	460	330	152	240

PN	DN	A	d	g	c	o	T	E	N-ΦD	H	H1	H2	G	B	Wt	Cv
1.6	450	864	436	550	585	640	40	4	20-30	923	200	393	600	463	1385	10740
	500	1016	487	610	650	715	44	4	20-33	958	200	436	600	463	1748	15460
	600	1219	589	725	770	840	54	5	20-36	1121	230	492	720	488	3405	23660
	900	1981	874	1000	1050	1125	64	5	28-39	1500	250	730	860	815	11198	47300
2.5 Female face	350	762	334	450	490	555	38	4	16-33	860	200	338	600	463	1080	59200
	400	838	385	505	550	620	40	4	16-36	943	200	372	600	463	1440	9250
	450	914	436	555	600	670	46	4	20-36	1048	230	414	720	488	1895	11320
	500	991	487	615	660	730	48	4	20-36	1094	250	465	860	770	2220	16050
	600	1143	589	720	770	845	58	5	20-39	1148	250	519	860	770	4430	26590
4.0 Female face	350	762	334	465	510	580	46	4	16-36	860	200	338	600	463	1080	59200
	400	838	385	535	585	660	50	4	16-39	943	200	372	600	463	1440	9250
	450	914	436	560	610	685	57	4	20-39	1048	230	414	720	488	1895	11320
	500	991	487	615	670	755	57	4	20-42	1094	250	465	860	770	2220	16050
	600	1143	589	735	795	890	72	5	20-48	1148	250	519	860	770	4430	26590
6.3 Female face	250	673	252	345	400	470	46	3	12-36	919	230	336	720	488	1055	5020
	300	762	303	410	460	530	52	4	16-36	950	230	361	720	488	1375	9160
	350	826	334	465	525	600	56	4	16-39	964	230	375	720	488	2228	9400
	400	902	436	535	585	670	60	4	16-42	1132	250	413	860	770	2338	10800
10.0 Female face	250	787	252	345	430	505	60	3	12-39	919	230	336	720	488	1055	5020
	300	838	303	410	500	585	68	4	16-42	950	230	361	720	488	1375	9160
	350	889	334	465	560	655	74	4	16-48	964	230	375	720	488	2228	9400
	400	991	436	535	620	715	80	4	16-54	1132	250	413	860	770	2338	10800
16.0 Female face	50	368	50	102	145	195	30	3	4-26	514	185	186	460	330	97	155
	80	381	76	138	180	230	36	3	8-26	582	185	171	460	330	126	245
	100	457	100	162	210	265	40	3	8-30	627	185	203	460	330	216	640
	150	610	150	218	290	355	50	3	12-33	710	194	270	500	372	530	2350
	200	737	201	285	360	430	60	3	12-36	908	230	303	720	488	618	4140
	250	838	252	345	430	515	68	3	12-42	1068	250	356	860	770	1956	5420

Dimension of Round Hole Full bore Type with Gear

Class	NPS	A	d	g	c	o	T	E	N- ΦD	H	H1	H2	G	B	Wt	Cv
150	2	267	50	92	120.7	150	14.3	2	4-19	424	155	158	320	265	114	525
	3	343	76	127	152.4	190	17.5	2	4-19	516	175	186	320	280	171	1280
	4	432	100	157.2	190.5	230	22.3	2	8-19	535	175	218	320	280	218	2330
	6	546	150	215.9	241.3	280	23.9	2	8-22	662	185	258	460	330	284	5250
	8	622	201	269.9	298.5	345	27	2	8-22	732	194	290	460	372	468	10800
	10	660	252	323.8	362	405	28.6	2	12-26	761	194	323	460	372	693	17500
	12	762	303	381	431.8	485	30.2	2	12-26	900	210	377	600	463	908	25600
	14	686	334	412.8	476.3	535	33.4	2	12-29	923	210	393	600	463	1308	31400
	16	762	385	469.9	539.8	595	35	2	16-29	958	210	436	600	463	1634	42500
	18	864	436	533.4	577.9	635	38.1	2	16-32	1042	230	484	720	488	3098	54700
	20	914	487	584.2	635	700	41.3	2	20-32	1067	230	507	7520	488	3351	70900
	24	1067	589	692.2	749.3	815	46.1	2	20-35	1269	250	590	860	770	6958	106000

Class	NPS	A	d	g	c	o	T	E	N- ΦD	H	H1	H2	G	B	Wt	Cv
300	2	283	50	92	127	165	20.7	2	8-19	500	175	159	320	280	142	520
	3	387	76	127	168.3	210	27	2	8-22	516	175	195	320	280	215	1250
	4	457	100	157.2	200	255	30.2	2	8-22	539	175	218	320	280	238	2280
	6	559	150	215.9	369.9	320	35	2	12-22	668	185	260	460	330	334	5140
	8	686	201	269.9	330.2	380	39.7	2	12-26	844	210	295	600	463	682	10580
	10	826	252	323.8	387.4	445	46.1	2	16-29	872	210	332	600	463	978	17100
	12	965	303	381	450.8	520	49.3	2	16-32	964	230	378	720	488	1359	25000
	14	762	334	412.8	514.4	585	52.4	2	20-32	982	230	408	720	488	1856	30700
	16	838	385	469.9	571.5	650	55.6	2	20-35	1154	250	460	860	770	2174	41600
	18	914	436	533.4	628.6	710	58.8	2	24-35	1185	250	501	860	770	3238	53600
	20	991	487	584.2	685.8	775	62	2	24-35	1216	250	532	860	815	3805	69400

Class	NPS	A	d	g	c	o	T	E	N- ΦD	H	H1	H2	G	B	Wt	Cv
600	2	330	50	92	127	165	25.4	7	8-19	510	175	171	320	280	217	510
	3	445	76	127	168.3	210	31.8	7	8-22	607	185	195	320	330	297	1240
	4	508	100	157.2	215.9	275	38.1	7	8-26	632	185	223	320	330	331	2260
	6	660	150	215.9	292.1	355	47.7	7	12-29	736	210	284	500	400	598	4640
	8	794	201	269.9	349.2	420	55.6	7	12-32	919	230	336	720	488	1185	9030
	10	940	252	323.8	431.8	510	63.5	7	16-35	956	230	375	720	488	1924	14790
	12	1067	303	381	489	560	66.7	7	20-35	1132	250	413	860	770	2663	23080
	14	889	334	412.8	527	605	69.9	7	20-39	1157	250	442	860	815	4305	29020
	16	991	436	469.9	603.2	685	76.2	7	20-42	1346	250	484	860	815	5164	39300

PN	Size	A	d	g	c	o	T	E	N-ΦD	H	H1	H2	G	B	Wt	Cv
1.6	50	267	50	100	125	160	16	3	4-18	424	155	158	320	265	114	525
	80	343	76	135	160	195	20	3	8-18	516	175	186	320	280	174	1280
	100	432	100	155	180	215	20	3	8-18	535	175	218	320	280	218	2330
	150	533	150	210	240	280	24	3	8-23	662	185	258	460	330	284	5250
	200	635	201	265	295	335	26	3	12-23	732	194	290	460	372	468	10800
	250	787	323.8	320	355	405	30	3	12-25	761	194	323	460	372	693	17500
	300	864	381	375	410	460	30	3	12-25	900	210	377	600	463	908	25600
	350	889	334	435	470	520	34	3	16-25	923	210	393	600	463	1308	31400
	400	914	385	485	525	580	36	3	16-30	958	210	436	600	463	1634	42500
	450	1219	436	545	585	640	40	4	20-30	1042	230	484	720	488	3098	54700
	500	1219	487	608	650	705	44	4	20-34	1067	230	507	720	488	3351	70900
	600	1524	589	718	770	840	48	5	20-41	1269	250	590	860	770	6958	106000

PN	Size	A	d	g	c	o	T	E	N-ΦD	H	H1	H2	G	B	Wt	Cv
2.5	50	283	50	100	125	160	20	3	4-18	500	175	159	320	280	142	520
	80	387	76	135	160	195	22	3	8-18	516	175	195	320	280	215	1250
	100	457	100	160	190	230	24	3	8-23	539	175	218	320	280	238	2280
	150	559	150	218	250	300	30	3	8-25	668	185	260	460	330	334	5140
	200	686	201	278	310	360	34	3	12-25	844	210	295	600	463	682	10580
	250	826	252	332	370	425	36	3	12-30	872	210	332	600	463	978	17100
	300	965	303	390	430	485	40	3	16-30	964	230	378	720	488	1359	25000
	350	965	334	448	490	550	44	4	16-34	982	230	408	720	488	1856	30700
	400	965	385	505	550	610	48	4	16-34	1154	250	460	860	770	2174	41600
	450	1219	436	555	600	660	50	4	20-34	1185	250	501	860	770	3238	53600
	500	1219	487	610	660	730	52	4	20-41	1216	250	532	860	815	3805	69400

PN	Size	A	d	g	c	o	T	E	N-ΦD	H	H1	H2	G	B	Wt	Cv
4.0 Female face	50	283	50	100	125	165	20	3	4-18	500	175	159	320	280	142	520
	80	387	76	135	160	195	22	3	8-18	516	175	195	320	280	215	1250
	100	457	100	160	190	230	24	3	8-23	539	185	218	320	280	238	2280
	150	559	150	218	250	300	30	3	8-25	668	210	260	460	330	334	5140
	200	686	201	282	320	375	38	3	12-30	844	210	295	600	463	682	10580
	250	826	252	345	385	445	42	3	12-34	872	230	332	600	463	978	17100
	300	965	303	409	450	510	46	4	16-34	964	230	378	720	488	1359	25000
	350	965	334	465	510	570	52	4	16-34	982	250	408	720	488	1856	30700
	400	965	385	535	585	655	58	4	16-41	1154	250	460	860	770	2174	41600

PN	Size	A	d	g	c	o	T	E	N-ΦD	H	H1	H2	G	B	Wt	Cv
6.3 Female face	450	1219	436	560	610	680	60	4	20-41	1185	250	501	860	770	3238	53600
	500	1219	487	612	670	755	62	4	20-48	1216	175	532	860	815	3805	69400
	50	330	50	105	135	175	26	3	4-23	510	185	171	320	280	217	510
	80	432	76	140	170	210	30	3	8-23	607	185	195	320	330	297	1240
	100	432	100	168	200	250	32	3	8-25	632	185	223	320	330	331	2260
	150	559	150	240	280	345	38	3	8-34	736	210	284	500	400	598	4640
	200	660	201	300	345	415	44	3	12-34	919	230	336	720	488	1185	9030
	250	787	252	352	400	470	48	3	12-41	956	230	375	720	488	1924	14790
	300	838	303	412	460	530	54	4	16-41	1132	250	413	860	770	2663	23080

PN	Size	A	d	g	c	o	T	E	N-ΦD	H	H1	H2	G	B	Wt	Cv
10 Female face	350	991	334	475	525	595	60	4	16-41	1157	250	442	860	815	4305	29020
	400	991	436	525	585	670	66	4	16-48	1346	250	484	860	815	5164	39300
	50	330	50	112	145	195	28	3	4-25	510	175	171	320	280	217	510
	80	432	76	148	180	230	34	3	8-25	607	185	195	320	330	297	1240
	100	432	100	172	210	265	38	3	8-30	632	185	223	320	330	331	2260
	150	559	150	250	290	350	46	3	12-34	736	210	284	500	400	598	4640
	200	660	201	312	360	430	54	3	12-41	919	230	336	720	488	1185	9030
	250	787	252	382	430	500	60	3	12-41	956	230	375	720	488	1924	14790
	300	838	303	442	500	585	70	4	16-48	1132	250	413	860	770	2663	23080
	350	991	334	498	560	655	76	4	16-54	1157	250	442	860	815	4305	29020
	400	991	436	558	620	715	80	4	16-54	1346	250	484	860	815	5164	39300

Reduced Bore Valve Operation Opening & Closing

Full Bore Valve Operation Opening & Closing

Pressure Relief System

To meet the requirement of API 6D, general dual seal plug valve used for the liquid must furnish one set of pressure relief system.

When twin seal plug valve closed properly and is full of the liquid. Due to the sunshine or hot environment, any tiny temperature fluctuation will result in the sharp variation of the pressure of the cavity.

Through the laboratory evidence, once the temperature raise 1°F. The pressure of full fuel will raise 75 Psi, certainly this data will be changed depending on the actual application conditions. (Subject to the medium, the container toughness exist air or not).

It is well known in the absolutely closed valve which is full of the liquid, may produce high pressure. So the twin seal plug valve used for liquid must equip with pressure bleed device.

Safe factor / DRT can basically realize the function of safe bleeding. However, actually all work parts are installed in the integral plate, The advantage of this device is fire safe, easy replacement for the whole part, all socket welding ends or joints, which may control to resulting in the accident effectively.

Manual bleed valve (MBV)

With the valve closed the Thermal Relief Valve releases any thermal expansion of the body liquid, back safely and automatically, to the line. Relief set at 25 Psi.*

Note: the "goose neck" pipe to prevent drainage of the body liquid.

Thermal relief to body (TRB)

With the valve closed the Thermal Relief Valve releasesany thermal expansion of the body liquid, back safely and automatically, to the line. Relief set at 25 Psi.*

Thermal relief to atmosphere (TRA)

Similar to TRB except thermal relief valve is set at 50 Psi above pipeline rated pressure and is vented to atmosphere.

Manual bleed valve with thermal relief (MTR)

The manual bleed proves drop tight sealing. The Thermal Relief Valve releases any thermal expansion of the body liquid, back safely and automatically to the line. Relief set at 25 Psi.

Manual bleed valve with gauge (MBG)

The manual bleed valve is combined with a gauge when emission to atmosphere is undesirable. The closing action of a valve automatically reduces body cavity pressure due to the expanding seating segments.

The gauge alone will indicate tight seals. (After a period of time, body pressure may again increase due to thermal expansion of fluid in the body cavity).

Thermal relief valve with gauge (TRG)

A thermal relief valve, to relieve anybody pressure which may build up due to thermal change, is combined with a gauge to indicate tight seals. No emissions to atmosphere. No sump system required. Relief set at 25 Psi.

The gauge alone will indicate tight seals. (After a period of time, body pressure may again increase due to thermal expansion of fluid in the body cavity).

*When a manual bleed or automatic bleed is fitted, the vent pipe should always be above the highest point of the valve body cavity. This will prevent liquid in the body cavity from dripping out.

Leakage past either seal would expel liquid from the already-full body cavity.

*The relief valve is set to open at 25 Psi on all valves, regardless of their working pressure.

With the valve closed, the relief valve will open at 25 Psi above upstream pressure.

This system functions only when the valve is closed and the isolation valve Is open.

CAUTION

A thermal relief system, piped back to the valve throat, converts the valve to a “DIRECTIONAL" valve. Thermal relief should always be piped back to the upstream side.

If It were piped to the downstream, any leakage past the main seal on the "up" side would be permitted to by-pass the "down" seal, by way of the directional check valve.

Thermal relief systems are designed to relieve excess pressure rise in the body cavity of a closed valve due to ambient temperature causing expansion of the liquid in the valve.

Some fluid is emitted at each actuation. A sump system is important as fluid will spurt out as the valve approaches the closed position and the cam opens the ABV. The spurting will cease as valve is fully closed for positive verification of double sealing.

Note: All automated valves require some form of body pressure relief. TRB/TRA/MTR/ABV/TRG

In normal service, the manual bleed is kept closed, unless to check for tightness or to vent thermal pressure rise. With automatic bleed or thermal relief back-to-line, the manual isolation valve that is attached to the body must always be open, except for maintenance. If the isolation valve is closed, the relief system cannot operate.