Quadruple butterfly valve 1

[MA123d]

thread408-355807

I agree with al1979.
even i was trying to know how the fourth offset is been achieved.
i have also downloaded the video provided by the manufacturer.
but still the question remains for me.
if any has this answer....please let me know.

 

[gerhardl]

OK. I tried to get a satisfactory explanation of the forth offset, and found the latest brochure from the company:

http://www.quadaxvalves.com/images/quadax/template/datasheets/Quadax Technical Brochure.pdf

confirming that:

1. Qadaxvalves is a daughter company of Muller CO-AX AG in Germany.
2. Former for many years specializing in heavy-duty triple offset valves.
3. Quadax valves specializing in quadruple offset valves.
4. The forth offset is described as a 'rounded' (completly round) version of the third offset. The third offset being the 'normal' section of an offset cone.
5. Verbal explanation : Third offset: Even if the cone is round the sectional straight cut will give an eliptical form for norrmal third offset. Fourth offset: If you start with an elleptical geometrical cone a sectional straight cut through the eliptical cone will be round)

The explanation is given in following video:

https://www.youtube.com/watch?v=t6rALiPgZtk

Seems clear to me, even if I have not experimented with paper cones to verify it, or sought out the patent itself.

If you search for quadax patent you will get a number of links.

 

[cranekiran]

Dear Gerhrdl,

Why the fourth offset?Is it for torque reduction?
Regards,
cranekiran

 

[bao2ye]

Using the four offset concept, the seal shape changed from oval shape to circular shape. This change makes the seal a circular ring shape instead of ellipse shape with a circle hole.

Considering thermal expansion and cold shrinkage, circular shape might generate more uniform shape variation than ellipse shape ring, especially for large size valve.

However, four offset valve still cannot make a evenly distributed contact stress due to the existing of cone angle offset and second offset.


Bao