What is the difference between double eccentric and concentric butterfly valves?

Double eccentric butterfly valves feature an offset shaft design that reduces friction between the disc and seat during operation. This results in lower operating torque, reduced seat wear, and longer service life compared to concentric butterfly valves, especially in higher pressure and temperature applications.

Can this valve achieve zero leakage?

Yes. The valve is designed to meet ISO 5208 Class A leakage standard, providing bi-directional zero leakage under normal operating conditions. The sealing performance depends on seat material selection and proper installation.

How do I select the correct seat material?

Seat material selection depends on the working medium and temperature: EPDM for water and general applications, NBR for oil and hydrocarbon media, PTFE for chemical and corrosive media, and metal seat for high temperature or abrasive conditions. Our engineering team can recommend based on your operating conditions.

What pressure and temperature ranges are supported?

The valve is available for pressure ratings from PN10 to PN40 (Class 150-300). Temperature range depends on seat material, typically from -20°C to 425°C. Metal seated valves are recommended for higher temperature applications.

Is the valve suitable for bi-directional flow?

Yes. The valve is designed for bi-directional sealing, allowing installation in either flow direction without affecting performance.

What standards does this valve comply with?

The valve is designed and manufactured according to international standards including API 609, EN 593, and DIN standards. Flange connections, face-to-face dimensions, and testing procedures all comply with relevant EN, ISO, and ASME standards.

Can the sealing components be replaced on-site?

Yes. The sealing ring and shaft sealing components are designed to be replaceable without removing the valve from the pipeline, reducing maintenance downtime and cost.

What documents are available for this valve?

We can provide full technical documentation including datasheets, dimensional drawings, material certificates (EN 10204 3.1), pressure test reports, and installation manuals. Third-party inspection reports (SGS, BV, TUV) are also available upon request.

API 609 EN 593 WRAS Approved

Double Eccentric
Butterfly Valve

High Performance Double Offset Butterfly Valve to API 609 for Reliable Shut-off in Industrial Applications

Designed for demanding flow control applications, this double eccentric butterfly valve ensures tight sealing, low torque operation, and extended service life. Suitable for water treatment, chemical processing, oil & gas, and general industrial systems.

Pressure Rating

PN10 / PN16 / PN25 / PN40

Class 150 / 300 Available

Size Range

DN50 ~ DN1200

2" ~ 48"

Seat Material

EPDM / NBR / PTFE / Metal

Temperature Range

-20℃ to 425℃

Depending on seat material

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On This Page

Product Overview

Industry Solutions

Typical Applications

Proven performance across the most demanding industrial environments worldwide

Oil & Gas

Designed for pipeline isolation and flow control in upstream, midstream, and downstream systems. Suitable for high-pressure applications requiring reliable shut-off and fire-safe performance.

Double eccentric butterfly valve installed in oil and gas pipeline system

Chemical Processing

Provides dependable sealing performance in handling corrosive and aggressive media. Available with PTFE or metal seats for various chemical conditions.

Water Treatment & Distribution

Widely used in potable water, wastewater, and desalination systems. Low torque operation makes it ideal for large diameter pipelines.

Double eccentric valve in water treatment facility pipeline

Power Plants

Applied in cooling water systems, steam lines, and auxiliary pipelines where stable performance and long service life are required.

Butterfly valve installed in power generation cooling system

General Industrial Systems

Suitable for a wide range of industrial fluids including air, water, and non-corrosive media, ensuring efficient and reliable flow control.

Butterfly valve in general industrial piping system

Not Sure Which Spec Fits?

Tell us your working conditions and our engineers will recommend the right configuration for your project.

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Engineering Excellence

Engineering Features

Engineered for long service life, low operating torque, and reliable sealing performance in demanding applications.

Double eccentric butterfly valve cutaway showing internal sealing structure and shaft assembly

Sealing & Corrosion Protection

Corrosion-Resistant Seat Design

Stainless steel welded body seat provides excellent resistance to corrosion and wear, ensuring long-term sealing performance.

Advanced Sealing System

T-profile resilient sealing ring, secured by retainer ring and bolts, delivers reliable bi-directional sealing. Easily adjustable and replaceable on-site.

Multi-Layer Shaft Sealing

Multiple O-ring sealing system prevents external leakage and protects against dust and media ingress. Maintenance can be performed without removing the valve.

Dry Shaft Protection Design

Seal gasket at shaft-disc interface combined with double O-ring bearings ensures a dry operating condition, minimizing corrosion risks.

Low Torque & Durable Structure

Optimized Disc Design

Streamlined disc profile reduces flow resistance while maintaining structural strength, verified by finite element analysis (FEA).

Low Friction Bearing System

Self-lubricating PTFE-lined or bronze bearings reduce operating torque and prevent shaft displacement.

Anti Blow-Out Shaft

Secure shaft retention design using taper pin or key connection enhances operational safety, suitable for vacuum service.

Actuation Flexibility

ISO 5210 top flange allows easy integration with electric actuators. Gearbox with handwheel ensures smooth manual operation.

Maintenance-Friendly Design

External locking mechanism enables gearbox removal without interrupting pipeline service.

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Double eccentric butterfly valve with actuator mounted for low torque operation

Coating & Surface Protection

All valves are externally and internally coated with fusion bonded epoxy (FBE) at a minimum thickness of 250 microns, color coded to RAL5005 / RAL5015 / RAL5017. Alternative coating and lining options are available on request to suit specific media and environmental conditions.

How It Works

Design & Working Principle

Understanding how the double eccentric design improves sealing performance and service life

The double eccentric butterfly valve features two offsets in its design, each serving a specific purpose to reduce wear and improve performance:

First Offset

The shaft is positioned behind the centerline of the disc, allowing the disc to move away from the seat immediately during opening, reducing friction and seat wear.

Second Offset

The shaft is offset from the pipeline centerline, creating a cam-like motion that ensures the disc only contacts the seat at the final stage of closing.

Result: This design minimizes seat wear, reduces operating torque, and significantly extends the service life of the valve. Compared with concentric butterfly valves, the double eccentric structure provides improved sealing reliability, especially in higher pressure and temperature applications.

Sealing Mechanism

The valve adopts a resilient or metal sealing system, allowing tight shut-off in both directions. The sealing performance improves as pressure increases, ensuring reliable operation under varying working conditions.

Double eccentric butterfly valve structure - exploded view showing first and second offset shaft positions

Not Sure If Double Eccentric Is the Right Choice for Your Application?

Our engineers can help you compare concentric, double eccentric, and triple offset designs based on your working pressure, temperature, and media conditions.

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Specifications

Technical Specifications

Detailed technical parameters for engineering selection

Size Range

DN50 ~ DN1200

Pressure Rating

PN10 / PN16 / PN25 / PN40

Class 150 / 300 available

Temperature Range

-20℃ to 425℃

Depending on seat material

Connection Type

Wafer / Lug / Flanged

Operation

Lever / Gearbox / Pneumatic / Electric

Seat Type

Soft Seat / Metal Seat

EPDM, NBR, PTFE or metal for high temp

Leakage Standard

ISO 5208 Class A

Zero leakage, bi-directional

Design Standard

API 609 / EN 593

Face to Face

EN 558 / ISO 5752

Flange Standard

EN 1092-1 / ASME B16.5

Top Flange

ISO 5211 / ISO 5210

Suitable Media

Water, Sea Water, Air, Oil, Chemical Fluids

Bill of Materials

Materials of Component

Premium materials selected for durability in water and industrial applications

Double Eccentric Butterfly Valve exploded component diagram with numbered part references

Exploded view with part numbers corresponding to the material list below

1 Gear Housing Ductile Iron, GJS400-15

2 Key Stainless Steel, 420

3 Upper Shaft Duplex SS, 1.4462

4 Packing Gland Ductile Iron, GJS400-15

5 O-Ring Rubber, EPDM

6 Bolt Stainless Steel, A2-70

7 Shaft Bearing Bronze, QAl9-2

8 Valve Body Ductile Iron, GJS400-15

9 Body Seat Stainless Steel, 316

10 Retainer Ring Stainless Steel, 1.4571

11 Disc Seal Ring Rubber, EPDM

12 Screw Stainless Steel, A2-70

13 Taper Pin Stainless Steel, 420

14 Valve Disc Ductile Iron, GJS400-15

15 Lower Shaft Duplex SS, 1.4462

16 Shaft Bearing Bronze, QAl9-2

17 O-Ring Rubber, EPDM

18 Shaft Cover Ductile Iron, GJS400-15

Need Special Materials for Your Application?

Carbon steel, stainless steel, duplex SS, and aluminum bronze bodies are available on request. We also offer custom coating and lining solutions beyond the standard fusion bonded epoxy (min. 300µm, RAL5005/5015/5017).

Send Material Specs

Valve Design Standards

Designed in accordance with EN 593, BS 5155, and DIN 3354 standards. The disc profile is optimized through finite element analysis (FEA) to ensure maximum structural strength, reduced stress concentration, and minimized flow resistance.

EN 593 BS 5155 DIN 3354

Flange & Face-to-Face Standards

Flange connections comply with EN 1092-1, ASME B16.5, ASME B16.1, and AWWA C207 standards. Face-to-face dimensions conform to EN 558-1 / ISO 5752 (Series 14 or Series 13), ensuring compatibility with international pipeline systems.

EN 1092-1 ASME B16.5 AWWA C207 ISO 5752

Testing & Certification

Each valve is pressure tested in accordance with EN 12266-1, achieving Class A (zero leakage) in both directions. All valves are 100% factory tested prior to shipment. Available certifications include EN 1074 and WRAS approval for potable water applications.

EN 12266-1 EN 1074 WRAS Approved

Standards & Compliance

Design Standards & Compliance

Manufactured in accordance with international standards to ensure reliability, safety, and compliance in global industrial and water applications.

Double eccentric butterfly valve exploded diagram showing components tested to EN 12266-1 and certified to WRAS standards

Need Certification Documents?

Quality Assurance

Quality Control & Testing

Strict quality control procedures ensure reliability, consistency, and compliance with international standards.

100% pressure and leakage testing before delivery

Strict dimensional inspection and material verification

Full traceability with material certificates (EN 10204 3.1)

Third-party inspection available (SGS, BV, TUV)

CNC machining of butterfly valve body on precision lathe

Hydrostatic pressure testing of double eccentric butterfly valve

Valve assembly line with quality inspection checkpoints

Dimensional inspection using precision caliper measuring tools

Leakage testing equipment for valve sealing verification

Final inspection and packaging before shipment

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Need Custom Specifications?

Whether you need non-standard sizes, special materials, or specific actuator configurations, our engineering team can deliver a tailored solution for your project.

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Dimensions

Dimensions & Drawings

All dimensions are in millimeters unless otherwise specified. Face-to-face dimensions comply with EN 558 / ISO 5752 standards.

Scroll horizontally to view full table

Dimensions Table – PN10

DN	L (S14)	L (S13)	H1	H2	H3	E1	E2	E3	E4	E5	E6	L1	D4
200	230	152	175	137	193	526	198	272	64	99	86	196	240
250	250	165	207.5	178	233	623	230	328	93.4	135	115	240	320
300	270	178	235	178	233	670	254	351	93.4	135	115	275	320
350	290	190	265	192	283	784	295	407	120	169	138	290	400
400	310	216	295	192	283	853	334	437	120	169	138	320	400
450	330	222	325	317	378	938	368	488	120	186	138	360	240
500	350	229	362.5	315	376	1019	400	530	148	214	166	395	400
600	390	267	425	315	376	1117	480	548	148	214	166	470	400
700	430	292	460	346	407	1308	563	640	185	265	196	480	400
800	470	318	517.5	346	407	1426	623	698	185	265	196	560	400
900	510	330	567.5	390	451	1612	698	789	230	333	232	618	400
1000	550	410	635.5	451	512	1773	766	882	230	368	232	600	400
1200	630	470	747.5	507	568	2112	910.5	1038	315	453	360	800	400
1400	710	530	847.5	599	660	2529	1063	1253	412	613	440	920	400
1600	790	600	970	599	660	2754	1172	1369	412	613	440	1060	400
1800	870	670	1070	777	838	3257	1416	1602	495	725	544	1170	600
2000	950	760	1177.5	777	838	3523	1583	1701	495	725	544	1290	600

Dimensions Table – PN16

DN	L (S14)	L (S13)	H1	H2	H3	E1	E2	E3	E4	E5	E6	L1	D4
200	230	152	175	137	193	526	198	272	64	99	86	196	240
250	250	165	202.5	137	193	568	219	293	64	99	86	240	240
300	270	178	227.5	178	233	670	254	351	93.4	135	115	260	320
350	290	190	257.5	178	233	720	279	376	93.4	135	115	280	320
400	310	216	287.5	192	283	834	320	432	120	169	138	310	400
450	330	222	312.5	192	283	903	359	462	120	169	138	340	400
500	350	229	340	317	378	988	393	513	120	186	138	370	240
600	390	267	395	315	376	1119	450	580	148	214	166	430	400
700	430	292	452.5	315	376	1217	530	598	148	214	166	480	400
800	470	318	512.5	346	407	1410	614	691	185	265	196	560	400
900	510	330	562.5	346	407	1530	675	750	185	265	196	615	400
1000	550	410	620	390	451	1712	748	839	230	333	232	670	400
1200	630	470	732.5	451	512	1971	865	981	230	368	232	800	400
1400	710	530	842.5	507	568	2313	1011	1138	315	453	360	920	400
1600	790	600	962.5	507	568	2588	1161	1263	315	453	360	1050	400
1800	870	670	1062.5	599	660	3038	1324	1501	412	613	440	1162	400
2000	950	760	1167.5	599	660	3255	1436	1606	412	613	440	1270	400

Need Dimensions for Other Pressure Classes or Custom Sizes?

PN25 and PN40 dimension tables, GA drawings, and 3D models are available on request. Tell us your project specs and we'll send the complete technical package.

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Customer Feedback

What Our Customers Say

Real feedback from engineers, procurement managers, and project teams using our double eccentric butterfly valves.

Industrial pipeline project using double eccentric butterfly valves

"We used these double eccentric butterfly valves in one of our pipeline projects. The sealing performance has been stable under relatively high pressure, and the operating torque is lower than we initially expected, which helped us reduce actuator size."

Project Engineer

Oil & Gas Contractor, Middle East

"We installed these valves in our municipal water system, and so far the operation has been smooth. Maintenance requirements are low, and the coating and sealing system have held up well over time."

Procurement Manager

Water Utility, Southeast Asia

"We selected this valve for handling mildly corrosive media. The PTFE seat option works as expected, and the leakage performance meets our requirements. The supplier also provided the material certificates and documentation we needed."

Technical Buyer

Chemical Plant, Europe

"We used these valves for a general industrial project. The dimensions were consistent with EN standards, so installation was straightforward. Overall manufacturing quality is good, and delivery was within the agreed timeframe."

Project Manager

EPC Contractor, South America

FAQ

Frequently Asked Questions

Technical questions engineers and procurement teams commonly ask about double eccentric butterfly valves.

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Double Eccentric Butterfly Valve