Double eccentric butterfly valves
AVK manufactures double eccentric butterfly valves in DN150-2800 which are 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, and AVK double eccentric butterfly valves are thus the safe choice for water supply applications.
Our range of double eccentric butterfly valves
- Integrated seat, replaceable stainless steel seat and welded stainless steel seat
- Plate disc (DN150-2800) and flow-through disc (DN700-1200)
- IP67 gearbox, IP68 gearbox and gearbox with ISO flange
- PN10, PN16 and PN25
Longer service life due to tilted disc
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.
Three seat designs
The integral seat design has a machined and epoxy coated ductile iron seat integrated in the body. The stainless steel seat design comes in two variants. One with a replaceable seat ring of stainless steel sealed with an O-ring to avoid leakages under the seat ring and one with a welded stainless seat machined and polished to give a smooth surface.
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.
Disc optimised for high performance
The disc is designed to minimise pressure loss via CFD simulations. The disc seal is shaped to secure fixation in correct position providing a very reliable function. The excellent rubber quality makes it possible to reduce the amount of rubber which ensures low closing 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.
Our double eccentric 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
AVK butterfly 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 handwheels.
Product approvals
AVK double eccentric butterfly valves are approved by
- DVGW in DN150-1200
- KIWA in DN200-600
- WRAS in DN700-1200
For larger dimensions all components are approved.
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.
