Pneumatic Tube Transfer

[KBILL44]

Hi folks.
I am trying to build a project that uses compressed air to propel objects through 1 inch tubing. And the object has to travel the length of the pipe system and then return to the beginning. The problem I'm trying to solve is how to have the object stop at the ends of the run in a controlled mannor. Object can not smash into the valves at the end of the runs.
Any advice on how to achieve this would be appreciated.


Thanks

 

[LittleInch]

Ok,

Some questions:

These objects - what are they - size, weight etc? Are they total sealed against the tube or are they being "blown" along with the air going much faster than the "objects" or the same speed.
How many objects at the same time?
Some sort of diagram would help....

what sort of pressure / velocity y are we talking about?
What sort of length of tube?

How is the air in front of the objects released / controlled?

At a simple level you control speed by controlling the exhaust gas
You control object speed by possibly increasing diameter of the tube or entering a vessel which allows the object to fall out of the moving air stream.


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[KBILL44]

Hi, thanks for the reply
The objects are 3 inch aluminum capsules with 1.2 inch diameter. A string of 5 of them. Approx. 0.5 lbs each (2.5 lbs total)
The objects are being blown, they wont be totally sealed as the transfer pipe ID is ~1.3 inch.

The pressure I am using is up to 10 psi, controlled by an air compressor, regulator and ball valves. trying to keep it as simple as possible.

The pipe run is ~50 feet with 4 90 degree bends.

My first thought was have a sensor at a point along the pipe to switch the air direction and act as a brake, but the objects end at horizontal runs, and I need to ensure the objects reach each end point.

To your point about exhaust air, I could try installing needle valves at each end to control exhaust even if the objects are not sealed.

I will draw up a sketch of the pipe run, and attach it when i can.

Thanks

 

[LittleInch]

If you've got a gap then all five will end up bunched together and could easily jam in the pipe.

It's not that different to pipeline pigging exercise where in many cases the main flow goes off the main pipe via a tee just before the pig trap / end of the line and the pig / object stops very quickly. The pig goes into the trap using a small differential pressure on the branch of the tee with a s mall flow going on the main run to slowly push the pig into the trap with an exhaust tot he low pressure side of the branch flow.

The key is velocity and how accurate you need the final location to be.

This gives you an idea but on the receipt of the pig often much of the flow goes via the bypass valve / line, which is closed in this animation.

https://www.youtube.com/watch?v=CDHtL-J1Xxo

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.