Options to avoid cylinder drift caused by center blocked valve leakage 1

[ERT]

Hi all,

Our plant standard for pneumatic valving is to switch to the center position on a center blocked valve for any pneumatic actuation that is exposed to an operator. We program the machine to hold the "clamp" position as long as the operator has booth of the anti-tie down buttons pressed, and then flip to center position upon release.

This all works fine, except sometimes the valves sometimes leak so that we get drifting of the actuation after about 10 minutes. We are using SMC SY series valves.

A brake cylinder is not practical for us.

Any advice is appreciated.

ERT

 

[BobM3]

Is it just the valve that is leaking? If so, maybe a second on/off solenoid valve that also blocks the flow? It won't help if there is leakage elsewhere.

 

[itsmoked]

If it's the cylinder that is leaking there is nothing you can do about it to my knowledge, short of braking, of some sort, which brings it's own problems.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[Newmanite]

When you say sometimes do you mean all the time as the temperature of the air passes through the valve increases?
Have you done any root cause to your problem?Is the air system clean?Is the air stream lubricated enough?Do you get water out of the air reliefs?