Thread: Opinion on this cylinder and a question too.

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I was going to use a screen door closer ( I am doing a 4 bar pop up) but after looking at the prices of all the fittings and the tap to get the fittings attached I realized I could spend 4 more dollars and get an actual pneumatic cylinder from Graingers. Then I would not have to worry about psi and I think I would have more flexibility too. The dilemma I have is that it is a double action cylinder and I have a 3 way solenoid. So now I have an open port on the cylinder and no spring action to reset the prop. What do I do with the open port. I was thinking I could put an exhaust muffler on it. Then the weight of the prop would reset the prop instead of the spring on the screen door cylinder slamming it down, which really put a beating on my prop last year. The air should just vent out the muffler when it resets. I am pretty new to this stuff but that makes sense to me. Thanks.

Here is the cylinder I was looking at.

Air Cylinder,3/4 In Bore,6 In Stroke - Pneumatic Cylinder - System Components - Pneumatics & Hydraulics : Grainger Industrial Supply

I was just reading about how to do this yesterday. Go here: FrightProps - Halloween Decorations, Halloween Props, Pneumatic Props, Animated Props, Halloween Accessories

You've got the idea! To make absolutely sure it resets you can rig a few weaker springs to pull it back down to the start position, add weights. I did this to a prop a few years ago (added springs, and then weights at the last minute as the sloped yard made it get slightly stuck in one position and I had not accounted for this when testing on a flat surface.) and I still use springs occasionally when using lower PSI just to give it a little potential energy to get the prop moving (damn inertia!).

yes, make sure you add a muffler to the open port, to keep debris out if nothing else.

You can alo get a muffler with a flow control on it to install on the exhaust port of your 3-way valve to control the return of your prop without slamming.

Wow , I love this forum. That was some quick responses. And very helpful. Thanks to all of you. Perfect.

I think you would be fine by letting gravity reset the prop. I do it with several of mine. I use double cylinders and 3 way solenoids all teh time in this type of application.

Single acting has a spring. Double acting does not. You will only need added weight if you use a single acting or a double acting with a 3 way solenoid. You need a 4 way solenoid to allow it to retract back into its original position which you really should have anyway since it is double acting.

1 input for the air in
2 input for air into left cylinder input
3 input for air into right cylinder input
4 input is the exhaust port which allows air to escape. Put an exhaust filter here.

I'd go with Diabolik's suggestion , add the adjustable muffler to the extra port then you can adjust the speed at which it retracts.