Thread: Pneumatic speed
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Unread 16-03-2010, 20:40
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Re: Pneumatic speed

Quote:
Originally Posted by jspatz1 View Post
Are you using two solenoid valves, one on each cylinder? Do so if not. In the past we have even used two solenoid valves on each cylinder (some inspectors crinkled their nose at this.) The flowrate through the valve is your primary bottleneck. Increase the amount of tension on your elastics until the return force of the cylinders can barely hold it back, this will maximize their contribution to your speed and force.
This may or may not be true. There can (and usually are) many 'bottlenecks' in a pneumatic system such as using 'Tee' fittings instead of 'Y' fittings. Do not assume that your bottleneck is the valves, instead test,test,test.

Quote:
Originally Posted by steppmjk View Post
We're using one valve for both cylinders.what kind of latch can I use to load the system?
Each cylinder has a volume that is to be filled. The valve has a flow rate (Cv) for which only a certain amount of air can pass (actually the flow rate is a curve based on pressure difference across the orifice). You'll need to find the appropriate flowrate to volume ratio for your needs.

Standard gate latch from home Depot.

Quote:
Originally Posted by Mark McLeod View Post
A regular gate latch is the most common I've seen used this year with a separate tiny cylinder to unlatch it.
If you do the precharge trick don't pull the cylinder all the way back when it latches. Leave a couple of inches of cylinder as precharge volume.

You can also do a variation, such as
  1. using a cylinder to pull back a heavily elastic powered kicker
  2. latching it back
  3. returning the cylinder to it's forward position
  4. opening the latch to kick
  5. repeat.
These tips are probably the best.

Quote:
Originally Posted by dtengineering View Post
Put your valves as close to your cylinders as you can so you keep your tubing runs short (you have to vent/pressurize the tubing as well as the cylinder, remember).

Try putting a clippard tank right next to the valves on the low pressure side of the system. That means you've got lots of 60psi air right next to your valves, and close to your cylinders. You can even use the brass fittings to connect your vavles directly to the cylinder.

Jason
Jasons tips are for if you do not precharge your system. If you do precharge your system then you want the volume between the valve and the cylinder (giving more air in the precharge) and the largest orifice in between (1/8" to 1/8" nipple fitting).

Good luck.
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