a) The interior lighting. b) Galvanized steel plate with water spray. c) Mobile, rotating banding wheel. d) Independent water tank with filter. e) The motor for the suction of water.
In the past most potters made their own, but now the laws to protect the environment and the people who work with sprays are very strict. It is a big box that is open on one side and when you buy one you must calculate the size you need in relation to your work.
It is designed to stop the spray spreading, for health reasons, cleanliness and to prevent the wasting of the glazes being used. They are electrically controlled and designed, so when functioning there is a curtain of non-stop running water inside, down the back wall. What is being sprayed is in front of it and the glaze is aimed towards the curtain. The extraction fan creates a strong stream of air that pulls the water down into a tank, where the glaze and the water are filtered and separated. The glaze, depending on the products it is made with, can be recovered and the water is drained and cleaned and automatically reused.
The web given below explains very well how to make a spray-booth not designed for pottery, so you would have to make one or two changes.
Link to Paint Booth