Glassblower at a university. Or blow -it -yourself of Pyrex glass tubing and a torch.. Like the glassblower at a county fair or art show- there are always there.
I made many of 1 inch plastic tubing, cut and glued into a Y shape. Usually acrylic tubing or polystyrene tubing- use "acrylic cement" or 5 minute epoxy . Wash them out. No odor is left after washing, and you have to wash them between tests anyway..
I have used these guys to make a custom 4-way olfactometer: http://yankeeglassblower.com/. It came out really nice. They may have some standard sizes of Y-tubes in stock. I see you are not in the US. I'm sure they can ship you, or you could find a local glassblower and save a lot of $ on shipping.
Professional glassblowers are always making custom equipment for physics and chemstry departments, so should be in business near big universities.
My plexiglass olfactometer parts were interchangable with the glass ports with flies and mosquitoes. Do the plastic ones quickly & first to see if your insects even move in the olfactometer. Your system as planned might be easily be too big or too small.
The above system is the standard one currently used for bioassays with predatory mites, so there shouldn't be too much issue with directly replicating it (hopefully!)
You can get fabricated or blowing instrument for olfaction from any chemistry or physics laboratory. Global Olfactometer Suppliers, SPECTRO GROUP OF COMPANIES, and can take an adivice from Chemical Industry Institute of Toxicology, 6 Davis Drive, P.O. Box 12/37,
I personally know the founders of ars-fla and have purchased top quality products from them for many years. They have constructed a huge variety of scientific equipment particularly adapted to olfactometric studies for moth pheromone work at USDA. The scientists at ars can make any design, but I recommend buying what they suggest, and get underway right away.
Ask Dr Toby Bruce [email protected]. Here they use lot of them.The one you required is being used by me for whiteflies.It was used for mites also. Bruce must be able to get you suppliers name.I am an outsider here.
Back in the day, we would make our own small olfactometer systems. They have to be small for mites. I would use polystyrene pill vials that can be cut by sawing with a metal-cutting (fine tooth) hacksaw blade, and glued together with superglue (to start) then sealed with 5 minute epoxy. A sideways vibrating Dremel or Harbor Freight (cheap imported) vibrating saw ($14) with fine tooth blade will cut these vials nicely. Fine mesh of Stainless steel can be purchased from Grainger, or glue in plastic cloth mesh. Nobody uses iron mesh anymore: Amazon and SIgma might not even have such an exotic material!