Noisy Air Cylinders

Depending on the production requirements you can install a needle valve assembly on each air exhaust line. This would slow the discharge rate of the air from the cylinder thus acting like an air cushion. The problem is that it will slow down the speed at which the doors can open and close thus slowing production. Most solenoid valve manufactures have assemblies with needle vales already built in which makes for a cleaner installation.

I use this method to control 4", 6" and 8" air actuated butterfly valves in a water purification plant to reduce water hammer in the system. For my application its ok if it takes 2-3 seconds for the valve to open or close I just didn't want instant open and close.

Thanks. We are using speed control valves now and that helps somewhat, but I think I need to support the gates somehow. There may be more side load than I think.

Use linear bearings to carry the side loads.

I have several peices of machinery that use a reed switch on the cylinders.They are set to interupt the control valve in the cylinder stroke prior to bottoming out. It switches the control valve instantaneous the other way acting as a break. Then switch back so that the cylinder completes its stroke. All the cylinders have cushions on them. The reed switch can be move and placed so that activates just prior to cushion. This reduces the forces on the cushion. This will also slow down operations but not as much as a flow valve. If the equipment you are talking about is PC or PLC based you may be able to in corporated just with switches and correcting the program if not you will need a timer. Timer will need to be adjustable to fractions of a second. If it switches on to long cylinder will start to go the other way.

You can find an air shock like your car's shock absorber. This shock comes many different sizes you can adjust to absorb your banging at the end stroke of the cylinder. Look for Endine Shock from any Phneumatic company. Good Luck.

The last responder with the hydraulic shock absorber has the answer. The proper name for this device is a linear decelerator. They are available in adjustable, and non-adjustable (self-compensating) models. If the shock sees the same amount of energy each cycle, the adjustable type will allow you to set it so the slide just kisses the positive stop of the shock. I had an application that didn't allow room for a shock, but that was the only solution. The problem was solved by installing non-adjustable shocks into the air cylinder piston. Two shocks at 180º would hit the cap, and two more facing the other direction would hit the cylinder head. The piston had 4 theraded holes for the shocks, and the shocks has positive stops collars to prevent over stroking of the shocks. The cylinder used in the application originally didn't have a large enough piston diameter to accommodate 4 shocks, and had to be increased by one bore size. The application worked great. I don't know if offering such a cylinder by my company is proper etiquette in this forum, so I will refrain until someone tell me differently. One last idea about shocks. They fail for the same reason most cylinders fail, and that is rod seal leaks. Both Enidine, and Ace Controls use brass rod bushings. If there is side load on the rod, and therefore the bushing, life will suffer. Enertrols by comparison uses a tool steal bushing in most, but not all of their shocks, and therefore is a longer lasting unit. www.enertrols.com. Air cylinders that use iron rod bushings will also produce longer life over those with brass bushings.