What is Double Eccentric Butterfly Valve ?

Double Eccentric Butterfly Valve is an innovative double offset design product with advanced world leading technology. This butterfly valve has a unique structure with ultra reliable sealing performance, wide working conditions and low operation torque.

the principal caracteristics of the double eccentric butterfly valves is the double eccentric,also called double offset disc design.

it allows the disc to move off the seat reducing running torque and seat wear,it’s a big advantage compared to the concentric butterfly valves.

The tension on the disc is released after a few degrees of opening which minimises wear of the disc seal. Furthermore, the design minimises the compression of the sealing which ensures low operating torques.

The shaft sealing is replaceable under pressure to enable easy maintenance. Sealings of EPDM secure tightness from inside and out, and NBR sealings protect against impurities and fluids from outside.

The low friction PTFE bearings ensure low operating torques and the protected shaft ends secure durability since there are no uncoated ductile iron surfaces exposed to the media.

Main features of Double eccentric butterfly valves

Sealing machnism of Double Eccentric Butterfly Valve

Main features of NORTECH double eccentri butterfly valves

• The unique dynamic-mount sealed PTFE seat design is flexible and highly reliable
• Lip seal structure can compensate for changes in temperature and pressure, keep seal
• Long service life, laboratory life can be up to 670,000 times
• Ultra-Reliable seal performance:bi-directional zero leakage
• it’s easy to replace the seat by removing the insert,convenient for maintenance.
• There is a safe blow-out structure at the top of the stem
• Excellent adjustment characteristics
• Fire proof design

Sealing machnism of Double Eccentric Butterfly Valve

Stem-upstream Type

When the media flows from the back of the butterfly valve to the front, the butterfly plate is self-sealed due to the upward thrust of the media and the pressure of the seat 

Stem-downstream Type

When the media flows from the front of the butterfly valve to the back, the medium generates thrust at the angle of the back of the seat and the butterfly plate forms a pressure self-sealing

Type of Operation for Double Eccentric Butterfly Valve

Handle lever for resilient butterfly valves DN40-DN200.

Manual gearbox operator for the full range butterfly valves.

Pneumatic actuator for full range of butterfly valves

Electric actuator for full range of butterfly valves

Free stem without actuator,customized for clients with your own actuators.

Technical specifications of Double eccentric butterfly valves

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What is the Double Eccentric Butterfly Valve used for?

High-performance double eccentric butterfly valve applications

1: High-speed high-frequency operating conditions: in the air separation system, can be done for a long time within 1 second switch,
Lifespan can reach 1 million times
2: High temperature operating conditions: The seat of the PPL material is suitable for high temperatures of 250 degrees C.
3: High-pressure double-sided 6-stage sealing conditions: in condensate finishing system has a wide range of applications.
4: Oxygen operating conditions: This valve after degreasing treatment can be used for oxygen operating conditions, in parts
In terms of preparation, assembly, testing and packaging, the valve is cleaned in strict accordance with procedures.
5: Vacuum conditions: standard high-performance (double eccentric) butterfly valve rated seal to achieve vacuum
2×10-2. Special high vacuum valves with a vacuum of 2×10-5  are also available.