Abstract: An improved apparatus for treating plate-like workpieces with a designated chemical solution, including printed circuit boards, includes: (1) a tray for holding the chemical solution, with the tray having an open top which is configured to receive a horizontally-oriented workpiece, with the tray having a top edge with a portion of the edge forming a dam over which the solution may flow and an opening in its lower portion where the solution can enter the tray, (2) a reservoir tank situated below the tray, (3) a feed line connecting the reservoir tank and tray opening, (4) a drain that returns the solution that overflows the tray top edge to the reservoir tank, and (5) a pump that circulates the solution from the tank to the tray and over the horizontally situated workpiece.

Abstract: An improved apparatus for treating plate-like workpieces with a designated chemical solution, including printed circuit boards, includes: (1) a tray for holding the chemical solution, with the tray having an open top which is configured to receive a horizontally-oriented workpiece, with the tray having a top edge with a portion of the edge forming a dam over which the solution may flow and an opening in its lower portion where the solution can enter the tray, (2) a reservoir tank situated below the tray, (3) a feed line connecting the reservoir tank and tray opening, (4) a drain that returns the solution that overflows the tray top edge to the reservoir tank, and (5) a pump that circulates the solution from the tank to the tray and over the horizontally situated workpiece.