Double eccentric butterfly valves
We offer double eccentric butterfly valves in DN150-2800 designed with durability in focus. The tilted and firmly secured disc, the optimised seal design and the corrosion protected shaft end zones are all features that exceed the market standards.
AVK double eccentric butterfly valves in DN150-4000 designed with tilted and fixated disc for extended service life and easy operation. The disc seal is made of AVK’s drinking water approved EPDM rubber featuring an excellent compression set and thus ability to regain its original shape. The DVGW/WRAS approved epoxy coating and fully encapsulated shaft/disc connection ensure high durability. The valves are suitable for bi-directional application.
Our product range
• Integrated seat and stainless steel seat
• IP67 gearbox, IP68 gearbox and gearbox with ISO flange
• PN10, PN16 and PN25
• Approvals by WRAS (UK), DVGW (Germany), GSK (Germany)
The tension on the disc is released after a few degrees of opening hich gives only insignificant wear of the disc seal. Furthermore, the design minimises the compression of the sealing which ensures low operating torques.
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Safe disc and shaft connection
The disc and shaft are connected by means of a key and a keyway. The key is secured with two set screws to prevent fluttering caused by flow velocity and necessary play in the key and keyway connection. In the large dimensions the disc is secured with two stainless steel drive dowels, with key and keyway as back-up.
Two seat designs
The integral seat design has a machined and epoxy coated ductile iron seat integrated in the body. The stainless steel seat design has a replaceable seat ring of stainless steel sealed with an O-ring to avoid leakages under the seat ring.
The disc seal is shaped to secure fixation in correct position providing a very reliable function. The Excellent rubber quality of disc sealing ring secures low torques. The EPDM sealing is approved by DVGW, KIWA and WRAS.
Shaft design features
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 butterfly valves are optionally available with a locking device which makes it possible to lock the disc in open/closed position if gearbox replacement becomes necessary.
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.
Bi-directional and slim design
The valves are bi-directional even though valves from DN700 and up are marked with an arrow indicating the preferred flow direction. We have also minimised the weight to make handling easier and to put less strain on the environment.
Actuation of your choice
We offer any type of actuation. Our standard options are IP67 gearboxes with handwheel for above ground installation, IP68 gearboxes for buried service, and ISO-input gearboxes for mounting of electrical actuators. Furthermore, we offer extension stems, adaptors and hand-wheels.
Where are double eccentric butterfly valves used?
Double eccentric butterfly valves are most often used in water supply applications below ground as an alternative to gate valves. When installing butterfly valves below ground a lower bury depth is required and typically, they are more cost-effective, especially in the large dimensions, compared to gate valves. They can of course also be used above ground.