The inset photo shows an agitator cap and filter similar to the Kelvy that granny had (given to her by a neighbor). The ad references it as a Filter Fountain. The agitator cap on granny's was a screw-on "cage-like" design of ~1.5" height with a flat detachable chrome piece (like in the photo) that fit atop it and anchored in slots when turned. I always assumed, even at a young and inexperienced age, that it operated via a burp-up method, regards to a what appeared to be a hollow tube in the center of the agitator beneath the chrome top cap ... water would shoot up through the tube, hit the botton of the top cap and shower into the filter. Such was not observed so I figured the tube was clogged which prevented the filter from working.
None of the Kelvys I've seen among the collectors who have them are the same agitator cap as was granny's.
Someone (John/Combo52?) recently commented in reference to the filter pan on someone's machine that it worked via Kelvinator's renowned splashing ... so presumably granny's was the same in that respect, not a burp-up.
