5 adjectives to describe ventilators

Now I couldn't find any openings in that large room except two little ventilators near the ceiling, so if that fire is going to burn, it must get air from this room.

Therefore, until we have made ample provision for the air supply to the fire, it is quite useless to attempt to ventilate the upper part of the room, either by ventilating gas lights or one of the cheap ventilators with little talc flappers, opening into the chimney when there is an up draught, and shutting themselves up when there is any tendency to down draught.

"In some of our theatres, the gas chandelier is made a very effectual ventilator.

But at the risk of seeming too contented for anything I will assert I heard that noise no more than one hears the drone of an electric ventilator upon one's table.

Nowhere have these drains been carried through the houses, but they are taken directly into drains at the back, having specially ventilated manholes and being brought through at the ends of terraces into the road sewers; the ventilating openings in the roads have been converted into inlet ventilators by placing upcast shafts at short intervals, discharging above the houses.

5 adjectives to describe  ventilators