Tony M Jul 21, 2015:

OK Even that helps a bit!

Unless you know for sure that these are gear-driven valves, I suspect gear has a quite different sense here: in many contexts, 'gear' means 'the bit that does the operating' — nothing specifically to do with toothed wheels!
With a bit of luck, that might help you to do further research along those lines in FR.

Julie Martineau (asker) Jul 21, 2015:

More context The only additional info I get is " TOP GEAR WITH CAP FOR GATE VALVE" and "SIDE GEAR WITH SQUARE CAP SC."

Tony M Jul 21, 2015:

Context? I think it is pretty unlikely that the 'gears' here are 'pignons' — however, it is quite impossible to tell without having more of your wider context to work with. Please give us enough of the rest of your document for us to understand how the terms are being used here.