i am trying to avoid drilling for another vent discharge orifice in my basement so was wondering if the exhaust ducting from a dryer can be joined with the kitchen fan exhaust duct and discharge it out through the same hole ?
The question, really, is what will prevent the laundry exhaust from entering the kitchen and vice versa. I don't know that one-way-valves exist for air ducts; I think you're much better off keeping them separate.
i would imagine a type of fitting would exist that prevents current in unwanted direction, i.e. makes sure air goes out but does not come in.
i would put such a fitting on the fan inlet just before it joins the dryer inlet and could consist of not much more than an inside flapper and a screen. the air stream out of the kitchen fan would be popping the flapper on the way out and the screen would be preventing dryer lint from coming into the fan duct in case of concurrent operation.