Air Mover Properties

1. Get rid of the rotating disc
2. Stick a bypass line round the rotating disc
3. Stick an accumulator vessel upstream of the rotating disc
4. etc.

I want to keep the rotating disc as that is the point of my mechanism.

I don't want to bypass the rotating disc as that is the point of my mechanism.

The airmover makes the air flow correctly when it is working (95 %) of the time. An accumulator will not keep the same air flow characteristics.

Flap valve... (Aka scrap of polythene sheet and some duct tape)
Del

then the air will just vent through the flap 100% of the time.

What does the rotating disc do?

It cuts.

What and how?

The airmover changes direction whether the disc is cutting or not. Can we keep on subject please.

Do you have any experience of an airmover. I didn't before I used one. it is not so intuitive as i thought.

http://www.brauer.co.uk/php/airmoveroverview.php

Here is the principle.

And the reason it cannot be changed for an electric motor that rotates this disc that cuts some off-topic material is what, please?

And the reason the air cannot be tolerated going backwards out the inlet port is what, please?

The rotating disc can be changed for electric, hydraulic, pneumatic or a monkey with a piece of string.

My question was about the airmover and the change of direction of the air, when the flow is interupted.

As for the question why the air cannot be tolerated going backwards.

I don't want it to go backwards. So I have asked a question about that.

I read this forum often, but sometimes I get quite annoyed by some people on this site, whose first impulse is say "not enough info" or start asking questions away from the original. I don't want to appear rude, as i appreciate that people take time out to answer questions. But I could write a big essay explaing all the in and outs about the simple machine that i have got, what it does, how it works etc. But all I would like to receive off somebody with a little bit of knowledge about airmovers, is how to stop the air changing directions. The tube is 10mm in diameter.

PWSlack's questions do not seem terribly "away from the original." He is asking for information which would likely in his, and my opinion, determine "how to stop the air changing directions." The fact you posted here means you desire some external insight to the problem, and your reluctance to help others help you puzzles me.

I have experience with cutting an extruded piece of thin walled tube. As we extruded the tube it was formed in a vacuum tank. When the cooled tubing was cut to our desired length it would collapse and the vacuum tank would pull (however slightly) more vacuum as the inside volume of the tube was briefly fixed. Thats a very general description of the mechanism, but the result was fluctuations in tube size (again however slightly.) The cutter we used was a rotating blade, we resolved the problem by creating a bushing which supported the tubing better so instead of deforming the tube before cutting it, the blade passed through without "pinching" the tube. Also we had to obtain a slimmer profile blade so that it did not "seal" the cut end of the tube as it passed by, e.g. the tube was .5" in diameter the blade had to be less than .5" wide. Maybe your blade can be modified to create less of a disturbance in the airstream through a different profile, (curved, staggered) or by having perforations or vent holes.

My limited experience with air movers of your type is that they cannot be totally blocked without interruption. Could the blade position be moved to the inlet of the air mover? Or could you experiment with a longer tube so that a quick blocking of the tube is compensated by a larger established flow farther upstream?

-T

you haven't explained how the tube is blocked by the disc, why could not the tube be moved out of the way?

you want assistance but you are making that difficult when you don't clarify a point.

I have never worked with an air mover, but it's not magic and intuitively I can see how it works, and intuitively more than one has suggested it's because of the disc that yours doesn't work 5% if the time.

How is the tube blocked by the disc?

Holes drilled at right angles to the tube.

Del's idea but a metered flap (relief valve) instead so the increased pressure when rotating disc blocks air can open flap without reversing direction...then when pressure is relaxed flap closes.

I have tried drilling holes in the tube, but the air just vents out of these holes. I was wondering why the air direction changes 180 degrees. I would have thought that maybe the air stopped moving in the direction it supposed to, but it does go out the wrong way. I've lowered the pressure of the airmover, but this just seems to to only reduces the flow and it still ends up with the air going in the wrong direction.

from the information of the working of the airmover, i would suggest the exhaust tube be larger in dia to allow the exhaust air place to expand and keep the lenth short, reason if lenth is too long back preasure may build up causing the airflow to reverse.

also if vented out to the outside wind blowing against the flow would cause reversal

also if not enough air is allowed to enter the mover from the input side this would cause the reversal

Please explain :

"also if not enough air is allowed to enter the mover from the input side this would cause the reversal"

I do not understand why if the outlet is free since the injected air is directed toward the outlet and even if it does not induce a flow it has already its direction given by the structure.

I do not say that you are not right only that this seems not coherent with the flow behaviour, thus my request for an explanation.

Thanks

I have an idea:

What if you allow the air to bypass the disk only when the disk has closed the normal flow... so that when the disk is closing the flow, it can go around, could the same disk be used?

Drill large holes in the cutting disk to let the air flow through.

or

Install a valve synchronized with the cutting disk to stop the flow of high pressure air when the disk is in the way. The high frequency will probably required a rotating valve with holes mechanically linked to the part of the machine that activate the cutting wheel.

Good luck

Anyone ask what the 'air' is for? It's purpose for being?

How about determining if the air 'problem' is a true problem rather than a "as designed" function-whether intended or not?

AB1 over & out.