New Concepts in Designing Butterfly Valves

May 18, 2011 11:42 am

WEIR BDK, one of the largest manufacturers of industrial valves with more than 25 years of excellence in fluid handling are offering various types of Industrial Valves to cater to the needs of different process applications.

Butterfly Valves being compact have their own advantage by occupying less space and the quarter turn mechanism makes the operation easier thereby reducing valve opening /closing time.

WEIR BDK offers different types in Butterfly Valves designed for specific applications.  Under the continuous quality improvement program, following new concepts in designing of Butterfly Valves have evolved.

Concentric disc Butterfly Valves (WEIR BDK model 12/model 44)
•      Wafer & lugged style body, compact design, easy for installation between the flanges
•      Metallic body is completely covered with a replaceable Elastomer seat from inside and does not come in contact with fluid
•      Seat with hard Phenolic back up (DN32 to DN300) avoids seat walking and makes the Valve fit for use for vacuum application
•      The Stem is connected to the disc by positive hexagonal drive and eliminates the use of pins and also avoids the possibility of failure due to sheering of the pins
•      ISO 5211 drilling on the top flange allows direct mounting of Electric / Pneumatic / Manual Gear Actuators.

Application: Water & waste water treatment plants, effluent treatment plants, and process industries etc.

New unique design at WEIR BDK
•      Seat has a cosine wave on the sealing area which not only ensures smooth opening/ closing of the valve but also reduces seating /unseating torques
•      ‘O’ ring housing in the stem bore of the seat provides primary sealing while the other ‘O’ rings on stem provide secondary sealing and also acts as weather seal
•      Delrin Bearings on stem ensures smooth operation and also transfers the torsional /axial thrust to the stationary body
•      Retainer plate on the top flange makes the stem blow out proof
•      A lateral groove on the top flange drains off any fluid coming through the stem sealing thereby avoiding fluid entry in to the actuators
•      10 position throttle plate on lever operated valves for control applications.

Eccentric disc butterfly valves (WEIR BDK model 85F/model 95)
Model 85F Butterfly Valves
•      Double Flanged (model 85F) body, compact design, easy for installation between the flanges in the pipeline
•      Eccentric design of the disc not only keeps the disc laterally away from the central line of the body and stem thereby reducing seating /unseating torques but also permits gradual positive sealing of the Valve to achieve 100 per cent leak tightness
•      Seal ring (Elastomer) is fitted on the disc outer diameter, field replaceable with valve installed in the Pipeline
•      Body is fitted with a replaceable seat ring made of stainless steel, which forms the sealing face for the disc seal ring.
•      ‘O’ rings on stem not only provide secondary sealing but also acts as weather seal
•      Leaded bronze bearings on stem ensure smooth operation and also transfer the torsional /axial thrust to the stationary body.
•      ISO 5211 drilling on the top flange allows direct mounting of electric/pneumatic /manual gear actuators.

Applications: Chemical & process industries, steel plants, thermal power stations water supply lines, cooling water towers, waste water treatment plants etc.

New unique design at WEIR BDK
The Elastomer Seal ring on model 85F butterfly valves is fitted on the disc outer diameter and positively locked in a dovetail groove. This design not only allows additional compression effect but also ensures positive sealing as the Seal ring gets adjusted itself in the groove depending on the interference of the disc and Seat ring.

The Seal ring is field replaceable with valve mounted between the flanges in the Pipeline. This new design also eliminates use of seat retainers and screws adding to the price competitiveness and also easier maintenance due to reduced components.

Model 85F butterfly valves are provided with gland packing arrangement, field replaceable with valve installed in the pipeline. The gland packing can be tightened through the gland flange to arrest possible leakage through stem if any.
Model 95 high performance butterfly valves
•      Wafer Style (Model 95) and Lugged Style (model 95L) compact body, easy for installation between the flanges in the pipeline
•      Eccentric design of the disc not only keeps the disc laterally away from the central line of the body and stem thereby reducing seating /unseating torques but also permits gradual positive sealing of the valve to achieve 100 per cent leak tightness
•      Seat (PTFE as well as metal) is fitted in the body and held with the seat retainer, field replaceable
•      Body is provided with a stopper to arrest overturning of disc
•      PTFE packings provide secondary sealing and also act as weather seal
•      PTFE bearings on stem ensure smooth operation and also transfer the torsional /axial thrust to the stationary body
•      Valves are supplied with Yoke having ISO 5211 drilling to allow direct mounting of electric / pneumatic / manual gear actuators
•      Provision for insulation of valves for high and low temperature applications.

Applications: Chemical & process industries, steel plants, thermal power stations, refineries, and petrochemicals etc.

New unique design at WEIR BDK
The fire safe design with primary seat in PTFE and secondary metal seat in SS316 with a backup ring to constantly exert uniform force on the seat for positive sealing.

The Seat is self energized with better sealing properties at high pressures and makes the valve bidirectional.

Metal seat in Inconel for high temperature applications.

Packings in graphite and stem bearings in Ni-resist for fire safe and metal seated valves to withstand high temperatures.

The thrust bearings to not only absorb the axial thrust but also make a continuous contact of trim parts with body to neutralize the static electricity charges.