Rotary Lock Paddle Cracking Issues

[mechengr12]

We have a few rotary locks that transmit PTA powder (similar to flour). Hard concrete like rocks form in the powder that get transmitted with the product. When this hits the rotary lock it puts a lot of stress on the paddles and cracks ensue. What are the best ways to support the blades? Cracks spread along the bottom through the side then the paddle breaks off. Plate running between the centers?

 

[Tmoose]

Has this always been a problem?
If not has the process changed, or parts now from a different supplier?
Do they bend before breaking? Would even be possible to tell?

I'm kind of lost without some pictures.
Welded construction?
Materials?
Poor geometry, even lurking in small features, or pre-cracked welds can murder an otherwise adequate design.

 

[Compositepro]

A rotary valve is not a grinder. If the lumps are rock hard you need a rock crusher ahead of the the valve.

 

[dvd]

Not the answer to the question asked, but you could protect the lock with a torque-limiting coupling -

http://www.zero-max.com/overload-safety-devices-with-torque-limiters-c-25-l-en.html

http://www.voith.com/en/products-services/power-transmission/torque-limiting-couplings-10102.html

 

[MikeHalloran]

Put bars above the lock, like the bars in a pipeline barred tee.



Mike Halloran
Pembroke Pines, FL, USA

 

[ornerynorsk]

Are the clumps forming inside or would a simple sieve relive the problem?

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

 

[mechengr12]

Bars and sieves would not be our best option as this may cause plugging problems. We remove the solids further down the line.

 

[Tmoose]

Hi mechengr,

is that a broken blade in the picture?
Is that a nicely developed crack in a blade in the background?

is, is, is ??

 

[MikeHalloran]

Then you need a rotary lock that is sturdy enough to crumble the lumps that are troubling you.


Mike Halloran
Pembroke Pines, FL, USA