What kind of check valves work best with mechanical lubricators? Brass flappers? teflon ball with a spring? Regular ball checks? I do not have any of the older style syphon check valves and would like to know what everyone uses. Thanks for any help
I've seen metal ball checks in old work, and have used new ones successfully too. Spring loaded, though I recall at least one old work that was gravity, though a spring could have been a removed long before I was inside it.
Teflon balls probably would work too, but the metal ones just seem appropriate for the application. I have used check valves with Teflon seals in water lines though, so really don't have an argument against Teflon.
For good insurance, one after the oiler and another shortly before entering the steam flow should keep your oiler and lines from getting full of watery goo.
I've found that swing check (flapper) valves work ok until they get a little gunked up, and then the swing gate doesn't seal completely, and steam blows back through the lubricator, making a complete mess. Also, the constant pulsation against pressure tends to wear that top swing pin rather quickly, causing the gate to move off center and not seal completely. I've found this to happen rather quickly.
The teflon ball and spring type work fine until the seat wears a groove on the ball and the spring gets weak. Again, no seal, blow back, and a mess. I couldn't get more than a season out of one of these.
I'm now using a ball check type (steel ball) that I got from Mcmaster-Carr. I've had it on my engine for 3 years now with zero issues. I haven't even taken it apart to clean it.