Double eccentric butterfly valves are more reliable, more durable and easier to maintain
The name Hawle is synonymous with quality. Hawle has been guaranteeing reliability and sustainability for more than 65 years. The new generation of double eccentric butterfly valves is no different. The valve does not touch the seal when it is open, ensuring optimum movement.
The name “double eccentric butterfly valve” comes from the position of the valve in relation to the shaft. The centre of the valve is located in front of and above the centre of the shaft. Most butterfly valves have a centric design. The Hawle butterfly valve has a double eccentric design. What is the benefit of that?
The valve does not come into contact with the gasket when it is open which ensures optimum operation. The result: less friction and reduced wear which in turn means less maintenance and a longer service life. The double eccentric design also provides better protection against water hammer.
There are also a number of very important benefits that make the innovative design of the Hawle double eccentric butterfly valve stand out:
- The worm wheel drive is extremely robust, guaranteeing a long problem-free service life.
- Uniform transmission of power from the drive shafts to the valve via a wedge rather than securing bolts. With securing bolts, transmission is not always uniform due to the variation in screw thread clearance and/or due to varying pressing forces exerted on the drive shafts by the securing bolts. A wedge fits very tightly in the wedge way (½ in the drive shaft and ½ in the shaft housing) which means that in fact, there is no clearance between the shaft housing, the wedge and the drive shafts. In addition, the force is equally distributed along the whole length of the wedge from the drive shafts to the valve.
- Stainless steel seat. With a lot of butterfly valves, the “seat” (the contact surface for the rubber seal) is pressed into a hollow chamber. That is not an ideal connection as it is neither 100% tight nor 100% firm. There is always a minimal seam between the housing and the seat through which moisture can penetrate. With the Hawle butterfly valve, the seat is welded in a chamber within the housing and a curved seat can be used. As a result, the connection is 100% tight and 100% firm. By using this welding method for the seat, there is no chance of moisture penetrating between the seat and the housing and an optimum seal is created.
- ISO top flange. Any type of drive (electrical, pneumatic or hydraulic) can be mounted on the flange without the need to make any adjustments.
- Drive shafts. The shaft housing is not sealed by a type of “stop” but instead consists of a single-piece cast unit which means that there is no risk of leaks.
Want to find out more about Hawle double eccentric butterfly valves? Then take a look at our products.
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