A butterfly valve is used for shutting off or modulates the flow of a fluid. They are often used as an alternative replacement in several applications with globe and ball valves. The key components of a butterfly valve are the disc, a metal ring that is positioned at the centreline of the pipe and connected to an external actuator via a rod. In comparison to a ball valve, the disc of a butterfly valve is always in contact with the fluid conveyed by the pipeline and hence creates a pressure drop. While remaining in the closed position, the disc blocks the bore of the valve, and in an open position, fluid is allowed to pass by the disc. For switching the valve from a fully open to a fully closed position, a quarter turn movement is required.
Concentric Type Butterfly Valve – Rubber Lined is a valve type having thick polymer lining on the body and the disc. The lining makes the body completely isolate from medium and provides excellent anti-corrosive performance. Easy assembly and operation can be experienced in extreme conditions because of the small dimension and lightweight which makes this valve type absolutely distinctive. Concentric butterfly valves are designed with an excellent bi-directional sealing function and zero leakage well suited for tight shutoff and regulation of diverse mediums.
This is the most basic butterfly valve design is commonly called a concentric or resilient-seated butterfly valve. In this valve type, the stem is centered in the middle portion of the valve disc, which is centered in the pipe bore. The valve conventionally has a rubber seat and relies on the disc having a high level of contact with the seat for an effective seal. During the 90 degrees rotation, the disc will contact the seat the earliest.
Dutco Tennant has a complete range of butterfly valves with sizes ranging from 50mm to 2000mm. The butterfly valve rubber lines are suitable for water applications. Rubber liner valves vulcanized on the body of the valve allows strong and reliable tightness along with the O rung cast of the body which prevents any need of gaskets. Mainly short and long body flanged butterfly valves are manufactured as centric type disc; they can stand both directions of fluid and are maintenance-free.
The concentric butterfly valve is used in water and wastewater treatment plants, fire protection systems, and gas supply.
Centric butterfly valves with fixed liner feature an outstanding seating concept. The rubber is injection moulded directly on the valve body forming a permanent bond. Consequently, there is no risk of deformation or dislocation of the liner making the valves suitable under vacuum conditions. The combination of the profiled disc edge and the excellent rubber quality ensures maximum durability of the liner.
- Concentric design.
- Bi-directional sealing..
- 100% tight shutoff, 0% leakage.
- Shaft bearings of PTFE coated steel.
- Streamlined disc with minimum flow resistance.
- One-piece body with flanges at the ends which give more resistance.
- Low torques as a result of the profiled disc edge and fixed liner design.
- The elastomer is vulcanized and allows use at pipe end without using a counter flange.
- The "face to face" distance allows interchangeability with other types of valves (gate,) one-piece shaft.
- Bonded vulcanized liner of drinking water approved EPDM with an excellent compression set and thus ability to regain its original shape.
- Profiled disc edge requires minimal deformation of the liner to achieve tight sealing, and results in less wear of the liner.