safety

I'm currently refurbishing a machine which will be controlled by a Mitsubishi Plc. Although all my E-stops and Guard Switches are externally wired will a dump valve be required. At present there are no dump valves on the system. If so can anyone direct me in the right direction.

Hi Doc,

I am afraid nobody here is going to be able to tell you what you will and will not need on your machine to make it safe. Machines and situations and local codes and definitions of "unsafe" are all different from one application to the next. You and yours are the ones who have to identify what is required.

As far as dump valves go, I believe you are refering to a quick acting compressed air valve used to de-energize air-driven components on a machine. If this is what you are refering to, then my answer is "probably a good idea" provided all the consequent reactions of de-energizing your equipment are considered and accounted for. What I mean is, you don't want a large part of your machine to come crashing down as a result.

In the States, OSHA requires that a "Locked-Out" machine is also free of uncontrolled "residual energy". Ways to control residual energy include releasing it, as with a dump valve, and mechanically inhibiting it, as with a pin or a block.

Hope this helps.

Steve