1) Go to KA basic search on JDog.
2) Add the "Rank" or "Global Rank" field as criteria.
3) Click on the new field.

You get an empty dropdown:

I've marked this as Minor because this searcher doesn't work in either Classic or KA in advanced mode - e.g. "Rank = 15475" returns no results on JDog, even though displaying the Rank column shows there is an issue with that rank.