[little_john]

I'm sure you've seen them - entrance feeders which have a perforated plate underneath a jar - relying on the meniscus formed underneath that plate or mesh to prevent dripping. But that's not the Boardman principle - his design was a true 'gravity feeder', the same as used for caged-bird drinkers.

I stumbled across some 'Gleanings' posts by Boardman last night, and here's the diagram he supplied:

As you can see, the key component is marked as 'B', and is a shallow dish or saucer with a raised rim which is clipped onto the jar, leaving a small gap for the syrup to run out into the dish. With such a small gap and a raised rim, the prospect of leakage is significantly reduced.

The 'anti-robbing' tangs (marked 'D') could always be further extended into the hive so that access to the feeder occurs several inches away from the entrance.

Not my choice of feeder, but hope the above proves of some passing interest ...
LJ

 

[viesest]

the prospect of leakage is significantly reduced

The lid with pocket filled with syrup prevents air to enter into (preferably plastic) jar. For me it is the solution for feeder (container) for syrup. No dripping, no drowning, no robbing, no refilling at a bee yard. (but last year I was feeding bees with home made fondant for winter stores)

 

[crofter]

These designs, whether regulated by an elevated rim or the meniscus effect of holes, are still subject to the temperature change effects and can cause leakage. A few dead bees up against the holes or in the rim can cause the contents to wick and continue to empty the bottle. Experience with chicks and chickens. There it only runs into the litter but with bees the robbing concerns or if used on a cover, dripping onto brood becomes a problem.

 

[Fivej]

Thanks for posting that LJ. Interesting. J