We currently have a pnumatic system, with a solenoid being energized/de-energized at given time intervals.  The Lime is in liquid form, and flows into an open tank via a 1" line with a pinch valve.
We would like to get rid of this loop, as it is the only air operated system in the building, and we have had some freezing problems (way up north here, and our process remains mostly indoors, so we do not have a nearby air dryer).
We desire to put in an electric driven valve, but, it MUST be fail-closed.  Thought of using a solenoid with 1" ports, and flowing directly through it, but fear it will be gummed up.  Would LOVE to find an electronic, fail closed pinch valve if such a thing exists.  Realise that I will likely have to get a rotating valve though, and that sliding stem is not a good option.
Worcester makes a fail-closed electric actuator: Model 72.  Coupled with one of their ball valves with abrasion-resistant Ultra-high molecular weight polyethylene (UMPE) seats, and you should be covered. 
Install with the stem horizontal and the actuator on the left when looking downstream so the rotation of the ball initially does not drag rhe settled grit into the seats.  Horizontal shaft also makes it easier to see the travel indicator, too.

MORE NEWS