Some time ago I ordered a cooking oil sprayer/mister from Aliexpress, this one. Looks like this:

When I first received it I put a bit of water in the bottle and tried it out and it worked great, I got a nice fine mist of water.

I then replaced the water with some oil, put it away in a cupboard and forgot about it until I needed it.

When I next went to use it instead of a nice mist of oil I got a thin stream of oil coming out, which isn't what I want.

Which got me thinking about how this is actually meant to work. As you can see from the image above, there's a long flexible tube that I assume sucks up the oil, and then there's a much thicker and shorter tube that sits in the centre of the bottle. I'm not sure what the purpose of that is. No instructions were included.

I've seen a few other oil misters around that have a "maximum fill" line drawn on the bottle, like this:

Which made me think that maybe the thick tube has something to do with air and you're not meant to have the oil go into this tube (even though the original image above clearly shows the oil extending way past the bottom of the thick tube).

I've tried it with less oil, where the oil doesn't reach the bottom of the thick tube, but this still creates a stream of oil rather than a mist. Replacing the oil with water results in a nice mist whether the water extends past the bottom of the thick tube or not.

Does anyone know how this is meant to work? Does it matter if the oil is clear of the bottom of the thick tube or not?