Cylinder position

[fun4sparkie]

I am trying to get ideas on how to sense when a equal acting hydraulic cylinder bottoms out on extend and retract. Do you have any ideas? I wanted to do this without limit switches.

 

[hydtools]

horsefeather, is it possible in your system for the cylinder to be stalled mid-stroke? This would give a false pressure indication that the cylinder reached full stroke.

If stalling mid-stroke is not possible, then a pressure switch will work for you.

Ted

 

[horsefeather]

Anything is possible.

My particular application is 3000 psi with a 28" travel and is used to crimp and shear oilwell pipelines.

Watching for the pressure dip on a gauge is how the operators determine closure now. The system is visually inspected (exercised) for correct operation before operations begin and the pressure drops are noted and signed on a chart recorder. This provides a reasonable assumption that the system will work in the vent of an emergency.

If absolute certainty is required that a piece of iron must be at a particular position, I agree with previous posters that a position sensing sensor (micro-switch, LVDT, etc) be used.