Quick Vacuum Release

[Calvin_1631]

Hello
I am very new to the concepts of pneumatics and this is our first year using them. We have gone with a vacuum design and are looking for a way to quickly release the negative pressure caused by the vacuum. What do we need to use in order to release the pressure? Is there a device that piab sells to connect to the end? (I have looked and don't know enough to know what I need to look for)

Thanks for the help and I hope everyone is getting close, or done, with building and testing their robots. I hope some of you might be able to make it down to Vegas to spend some time with us. Thanks!

[DonRotolo]

In testing we have found that stopping the air pressure flow to the venturi device causes the vacuum that was generated to release in well under 1/10 second.

Note that we do not have much in the way of volume (cubic inches) of space that is under vacuum - just a few inches of hose and the suction cup itself (the volume between the cup and the tube being held).

If your robot configuration is really different from that, let us have some details. Basically, you release vacuum just like you release pressure - vent to atmosphere.

Don

[Calvin_1631]

Our configuration has the suction cup up on and arm and there is about 4' of tubing between the suction cup and the compressor. Thus it takes about 1.5 seconds to release the tube. We were hoping that there would be a device to attach between the suction cup and the tube that would allow us to open a valve to the outside.

[Rickertsen2]

Piab does have off the shelf solutions. Basically what they do is shoot a burst of pressurized air into the cup to release it. You could easily make a system to do this out of kit parts by using an extra valve.

[Calvin_1631]

http://www.piab.com/Templates/WebBas....aspx?id=10211
http://www.piab.com/Templates/WebBas....aspx?id=13784
http://pisco.com/prodtype.aspx?prodtypeid=76
http://pisco.com/prodtype.aspx?prodtypeid=80

Can I use any of those generators that have a quick release by sending an electric current to activate a release valve? Also remember I don't understand any of this technical talk that has to do with pneumatics. Thanks, and sorry for being so annoying!

[DonRotolo]

Originally Posted by Calvin_1631

Our configuration has the suction cup up on and arm and there is about 4' of tubing between the suction cup and the compressor. Thus it takes about 1.5 seconds to release the tube.

The critical issue is the amount of tubing between the vacuum venturi and the suction cup. Secondary is the distance between the solenoid valve and the vacuum venturi. Make these very short (the critical one as short as possible - ours is mounted on the arm!) and you'll see results.

At the very least, try it as an experiment to see what happens!

Don

[Calvin_1631]

so i want the vacuum generator hooked up to the solenoid. So I connect the pressure from the compressor P on the double solenoid. Then which hole do i connect the generator to? And by sending power to one of the sides it will open the exhuast valve? And are both A and B always open, as I only want to hook one device, the vacuum, to the solenoid?

[Calvin_1631]

Please, I would appreciate any help and today I tried to work the solenoid.
I hooked the pressure from the compressor into the P hole. I then I hooked the vacuum up to the A hole with the B hole blocked. It didn't give me enough suction when i powered the compressor up. I used the manual switch on the solenoid and pushed that down on the A side but it didn't really do anything. Am I hooking it up all wrong? And does the air automatically come through the hole, or do you have to send some electricity through it, or how do you do it manually?

[MikeDubreuil]

It sounds like you are using a double solenoid valve to control the Venturi. Generally, double solenoids are used on pneumatic cylinders when you would like the cylinder to push and pull with great force. This is done by controlling the flow of air through two controllable valves; hence double solenoid.

You only need a single solenoid valve such as the Festo or single solenoid SMC. When you want your suction cup to work the solenoid valve must be open allowing compressed air into the Venturi pump and causing the suction cup to, well suck. When you don't want suction the solenoid valve should be closed, the suction will be relieved by flowing back through the Venturi and your cup will stop sucking.

FYI, FIRST has a pneumatics manual on their website.