Need a valve for retention of compressed air in cylinder

[kunalv]

Hello all!

I am designing a machine which consists of a horizontally mounted vessel which has a movable lid. The lid is moved up-down with the help of a pneumatic cylinder & is guided on linear bearings.

My question is during maintenance, when the lid is UP, and for any reason there is a failure in the pneumatic circuit (air pipe bursting or coming off, cylinder failure), the lid may come sliding down which may cause a major accident.

So, is there a valve that can be mounted just before the cylinder, that will 'lock' the air inside the cylinder and not let it exhaust?

The scheme of the machine is depicted in the attached picture.

Any help would be appreciated.

Thanks,

KV

 

[BvU]

For what it's worth: If you don't trust the pneumatic system, then you shouldn't trust yet another valve either.
How about ensuring the lid doesn't come down by means of a mechanical blocking device ? Ideally there should be an access door or a cage or something preventing access to the cylinder unless the lid is up AND blocked .

 

[JBA]

First, I agree with BvU with regards to the need for a mechanical latch; and, preferably one that requires the operator to unlatch each time the cover is closed and cannot be unlatched if the door is not fully lifted by the cylinder.

Having said that, one possibility would be to place a non-return check valve in the air feed line before the cylinder vent valve with both immediately before the cylinder inlet connection.