sorry if this is a STUPID question, But, the tuyer(or however it is spelled [tweer]) IS the air volume control right?, the valve that controls te amount of air input into the forge?

I think it is the assembly, the tube that allows the entry of air into the forge, and the associated clinker breaker assembly may be in it, the air valve is a stand alone, I believe, could be wrong....

ya twer or twe iron is the pipe or nozel going into the forge also you can call the cast iron box with clinker breaker a tewer ..many speelings of that ...kinda like ball pien or pane ..(you say tomatea i say tomata )

right...okay, so the tuyeer*(whatever) is a generality for the entire assembly?

Tuyere, a French word wouldn't you know, so it doesn't write in English like it sounds. It's a pipe in French or so the dictionary said. Defined as, "a nozzle through which an air blast is delivered to a forge or blast furnace."

The tuyere is the nozzle through which the air passes into the fire (originally these were at the bottom of blast furnaces used for smelting iron)

The air blast needs to be variable, so a valve of some sort is used on the modern day electric powered fans.

(Bellows were more sensitive to use, and hand cranked blowers were also more easily controlling in this)

This control can be achieved by various means, a slide valve mechanism arrangement, or electronic speed controllers being another alternative, some use a blade/slide valve, or a handwheel operated pipeline valve

On the pics attached of a side blast forge, you can see the fan/blower with
the air pipe carrying the air blast that has a slide valve arrangement to control the airflow, passing through the water filled tank which then has a shroud extending the water tank into the fire area with the tuyere attached to a plate at the front of the tank, positioned at the base of the fire.

The water cooled jacket preventing the tue iron from burning back on itself, this is not necessary on a bottom blast forge, as there is less danger of the tue iron face (Be it a grill, slots or just a large hole) burning away when in use.

Hope this clarifies it for you.

Here's another pic for reference

Blacksmiths Depot |Fire Pot with Tuyere and Ash Dump