INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

Pressure & Flow - Reciprocating pneumatic piston pump - Help!

Pressure & Flow - Reciprocating pneumatic piston pump - Help!

(OP)
Hi Team,

I'm going to try and keep this as short as possible (solve one problem at a time).

I'm trying to choose a reciprocating pneumatic piston pump to suit my application -pumping automotive fluids from a storage tank to a hose reel & dispenser out of a metered dispenser.

The main thing i'm struggling with is the pump performance charts. I've read through this from Graco (Pages 26 & 27 of the PDF or 24 & 25 of the document) - Link

I don't understand why when the flow rate goes up while the outlet pressure required drops (it's the same with all the pump of the same type not jsut htis example)- I understand this may have something to do with boyles law, but I can't find anything that explains how to apply it do a dynamic system.

Another contribution to my confusion - When you compare it to double diaphragm pumps they are the opposite - Link. I would use one of these but the calculated pressure loss is too high in the system :(

Any links or help appreciated. Feel free to roast me if i'm missing something simple :)

RE: Pressure & Flow - Reciprocating pneumatic piston pump - Help!

The flow rates are SCFM which is air at STP. These air motors do not have internal expansion so the air consumption per stroke is essentially the swept volume of the motor piston but at the supply pressure. If the supply pressure is increased, the same stroke consumes the same volume at supply pressure but this equates to a greater volume of air at STP.

je suis charlie

RE: Pressure & Flow - Reciprocating pneumatic piston pump - Help!

(OP)
Ahk, Excellent I get what you mean. I've been looking at it in the wrong order for what i'm trying to work out I think.

Now for part 2.

Is my thinking process correct?

Would I be correct in saying that one of the ways I could find the max flow is to use the SCFM & the air pressure (it can be regulator to suit specs) of the air compressor to give me my max fluid flow which I can use the performance chart to give me the fluid pressure?

If the above is correct do I then work out my pressure loss in the system and take that from the pump fluid pressure and as long as that is a positive number we'll get our max flow?

Or is there an extra step i need to do to work out actual flow taking into account the pressure loss?


Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close