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Butterfly Valve Series

• Cast Iron Butterfly Valves
• Ductile Iron Butterfly Valves
• Stainless Steel Butterfly Valves
• Triple Offset Butterfly Valves
• AWWA C504 Butterfly Valves
• Large Diameter Butterfly Valves
• Sanitary Butterfly Valves
• Flanged Butterfly Valves
• Lug Butterfly Valves
• Wafer Butterfly Valves
• High Vacuum Butterfly Valves

Product drawing»

Structural drawing»

D343H Metal-Seated Butterfly Valve Series

product drawing

Overview

The D343H Metal-Seated Butterfly Valve is a flanged butterfly valve featuring a multi-layer metal hard-seal structure, which achieves tight shutoff through the triple eccentric principle. The valve incorporates a triple-eccentric geometry—axial eccentricity, radial offset, and conical angle eccentricity—allowing the disc to completely disengage from the metal sealing ring during operation, with wedge-type compression sealing only occurring at the final closed position. The valve stem is driven by a worm gear mechanism, enabling smooth operation and providing a self-locking function. The sealing pair consists of a composite laminated structure with stainless steel sheets and flexible graphite, or the disc sealing surface is overlay welded with hard alloy, forming a high-hardness, wear-resistant metal sealing system with the metal seat of the valve body. This design makes the valve suitable for demanding applications involving high temperatures, high pressures, and media containing solid particles.

Features

1、Multi-Layer Metal Hard Seal: The sealing pair adopts an elastic sealing ring formed by alternately laminated stainless steel sheets and flexible graphite, or the disc surface is overlaid with hard alloy, creating multiple sealing barriers. This structure provides excellent wear resistance, high-temperature tolerance, and extended service life.
2、Triple-Eccentric Design: Based on precisely calculated three-dimensional eccentric geometry, the disc completely disengages from the sealing ring at the moment of opening, eliminating friction during rotation. During closing, the eccentric distance enables progressive wedge-type compression, ensuring reliable sealing with low operating torque.
3、High-Temperature and High-Pressure Resistance: The metal sealing structure allows the valve to operate long-term in high-temperature environments up to ≤425°C, with pressure ratings reaching PN16–PN40. It is suitable for industrial media such as steam, thermal oil, and high-temperature flue gas.
4、Erosion and Corrosion Resistance: The hard sealing surfaces effectively withstand erosion and corrosion from solid particles, crystalline substances, or mildly corrosive components in the medium. The valve body interior can be coated with anti-corrosion layers to extend overall service life.
5、Bidirectional Zero-Leakage Sealing: Leveraging the self-energizing effect of the eccentric design, the valve achieves metal hard sealing under both forward and reverse pressures, meeting bidirectional zero-leakage standards. Installation is not restricted by medium flow direction.
6、Long Life with Low Maintenance: The worm gear mechanism ensures smooth and reliable operation, while the hard sealing pair offers exceptional wear resistance. Under normal operating conditions, the valve can function maintenance-free for extended periods, making it particularly suitable for critical processes in industries such as power generation, metallurgy, and chemical processing, where high reliability is essential.

Dimensions & constructral diagram

The main technical parameters

Performance Specification Table

Item	Specification	Unit
Nominal Pressure	1.6	PN
Strength Test Pressure	2.4	MPa
Seal Test Pressure	1.76	-
Operating Temperature Range	≤425	℃

Standard

Performance Specification Table

Item	Specification	Unit
Nominal Pressure	1.6	PN
Strength Test Pressure	2.4	MPa
Seal Test Pressure	1.76	-
Operating Temperature Range	≤425	℃

The main external and connection dimensions

Principal Dimensions and Flange & Bolt Specifications

Nominal Diameter (DN)	Principal Dimensions			1.0MPa Flange & Bolt Specifications			1.6MPa Flange & Bolt Specifications			2.5MPa Flange & Bolt Specifications
	L	H1	H	D	D1	n-d	D	D1	n-d	D	D1	n-d
50	108	350	112	165	125	4-18	165	125	4-18	165	125	4-18
65	112	370	115	185	145	4-18	185	145	4-18	185	145	4-18
80	114	380	120	200	160	4-18	200	160	8-18	200	160	8-18
100	127	420	138	220	180	8-18	220	180	8-18	235	190	8-22
125	140	460	164	250	210	8-18	250	210	8-18	270	220	8-26
150	140	550	175	285	240	8-22	285	240	8-22	300	250	8-26
200	162	765	200	340	295	8-22	340	295	12-22	360	310	12-26
250	165	830	243	395	350	12-22	405	355	12-22	425	370	12-30
300	178	895	250	445	400	12-22	460	410	12-26	485	430	16-30
350	190	950	280	505	460	16-22	520	470	16-26	555	490	16-33
400	216	1190	305	565	515	16-26	580	525	16-30	620	550	16-36
450	222	1255	336	615	565	20-26	630	585	20-36	670	600	20-36
500	229	1305	380	670	620	20-26	715	650	20-36	740	660	20-39
600	267	1340	445	780	725	20-30	840	770	20-36	865	770	20-42
700	292	1520	480	895	840	24-30	910	840	24-36	960	875	24-42
800	318	1710	530	1015	950	24-33	1025	950	24-39	1085	990	24-48
900	330	1870	580	1105	1050	28-33	1125	1050	28-39	1185	1090	28-48
1000	410	1960	650	1230	1160	28-36	1255	1170	28-42	1320	1210	28-56
1200	470	2250	760	1475	1390	32-39	1485	1390	32-48	1530	1420	32-56
1400	530	2435	830	1655	1580	32-42	1685	1590	36-48	1755	1640	36-62
1600	600	2780	1020	1915	1820	40-48	1930	1820	40-56	1975	1860	40-62
1800	670	3020	1250	2215	2020	44-48	2190	2020	44-56	2204	2070	44-70
2000	760	3270	1350	2325	2230	48-48	2435	2230	48-63	2425	2300	48-70

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