Think of a sugar dispenser. It provides an equal "dose" of sugar every time you push its button.
In my native language, Bulgarian, we have a specific word for this kind of object. The literal "translation" of it would be "dosator"/"dosager". The general word 'dispenser' doesn't capture the fact that the dose is equal each time. So is there a precise word for this?
(I needed that kind of word for a metaphor in a class name in a computer program I'm writing)