long distance air lines

[hrc]

I have four air solenoids that I will be controlling, each giving a short (1 sec) burst of air, more or less in a random order. The amount of time between bursts will also be under my control. However, the question is how to size out the air compressor and tank, and also the air line? The requirement is to have the main tank some 100' or so from the solenoids and still have enough air pressure to burst each one. Do I need four lines out from the compressor or will one larger line suffice? And if so, what are the calculations for the air line? These lines will be buried so I can't simply run them after if it doesnt work.

 

[AirTrainer]

HRC,

Every pneumatic sizing application requires quantification of the details. Once the specifics of the application are defined, then you can begin the process of sizing the components needed to support the application. Essentially, you work your way backwards.

I am guessing that the duration of roughly 1 second comes from past experiences, but it is important to be decided upon the specific duration that any given valve will be flowing air. Also, is it possible that more than one valve will be energized at a time?

The first step in this process is to determine what work needs to be done, and how much energy (in the form of compressed air) needs to be expended to get the work done. It is also necessary to explain if this is an air blow application that is open to atmosphere, or if it is a limited duration closed system application such as a short-stroke actuator. Then, the application has to be quantified in terms of X CFM consumed at a pressure of Y PSIG.

If you can provide me with more detail, I will help you with this.

Best regards....

 

[hrc]

Thanks for the response. I'll try and give as much information as I can, and then see what else you need.
First, this is an open air blow design sort of (actual application is a water cannon where the air will blow out water from a small well), and the duration of one second is more of a guess, but I will have full control over it as I am doing the controller for it. This is an addition of an existing project, where the existing water cannons have the air compressor within a few feet of the solenoids. I had to adjust the delay between shots to both allow the water to refill as well as the air pressure to rebuild. Only one valve will be open at any one time, but the controller will sequence thru each of the four valves in some sort of random pattern, thus I was thinking that each valve might need its own airline, else the system might be depleted of pressure unless a reserve tank was located locally. So far, does this make sense? Worse case scenerio is that we run four air lines (what size) to the location and see how it reacts. Its better to have too much buried in the dirt than need to run another line after the fact.

 

[AirTrainer]

Sorry for the delay in my response.

Here are a few more questions. By what distance will the solenoids be separated? By what distance will the discharge ports of the water/air be separated from each other as well as their respective solenoids? If we determine it is appropriate, can a pneumatic reservoir be located closer to the overall application?

And, yes, this does make sense. You and your customer would be distinctly unhappy if you accidently undersized your pneumatic system.

Speaking of which, it is important to determine if the existing compressor has sufficient capacity for the additional demands. If you can advise the HP, general construction type, and manufacturer, we can start to determine if it is working close to it's maximum capacity.

 

[hrc]

The solenoids can be placed near the actual discharge point, say within 6 feet or so. The four units are also located within a few feet of each other as well. It has been discussed with the client about locating a reservoir near the solenoids as an option, but he would rather out one larger compressor and tank remotly. Presently this unit is not spec'ed out, so the field is wide open on what can be used. Power wise, we have 480 3 phase, 240 biphase and of course 120 single phase.

 

[freedesigner]

I have done something similar to what you are doing.
I used a small deposit, I believe they call them accumulators.
They are only small sized tanks of aluminum or other materials, you place them near the valve:
___
COMPRESSOR=======(ACC)==[VALVE]=>>> SYSTEM
~~~

You size them according to the amount of air you require for the burst.
I hope I interpreted your problem correctly.

good luck

 

[Tom001]

The response from Freedesigner is very feasible, is it possible to place a small reciever close to the valve, we have used a design similar to this to blast dust out of filter medium, the reciever is only small (approx 10" * 4" dia) and provides a reasonably good reserve of air.

Good Luck

Tom

 

[wedgee]

You might want to put in a loop. That way if the pressure drop is to great it can draw from both sides to maintain proper pressure within the system.