Tucker sell twin hose poles with a mixer chamber style container. You put the detergent tablet in the mixer, turn the valve on, water goes through it up through the pole and out at the brush to lather the glass and frame. Then turn the valve off.
Turn the other valve on and pure water is sprayed out through an overhead wide fan above the brush head. Good for 1st cleans for getting the worst off the frames and glass if the windows are really bad, except that the overhead spray hit's the lintels and brickwork above the windows.
It's best for cleaning conservatory roofs and fascias, soffits and guttering.