Spray gun for cleaning and removing standing particles from wafers and

Abstract

A hand-held spray gun comprises a pistol grip handle and a trigger that can be squeezed toward the pistol grip for actuating a poppet valve in the spray gun body to discharge fluid through a nozzle in the end of the spray gun. The poppet valve extends axially through a supply chamber which receives fluid passing to it through the interior of the pistol grip which, in turn, is connected to the source of the fluid, such as a liquid or gas. The supply chamber is sealed from a larger dispensing chamber through a seal carried on the poppet valve. The dispensing chamber communicates with long, narrow discharge passages in the nozzle end of the spray gun. The end of the poppet valve is enlarged to form a valve guide that slides back and forth in a valve guide cavity in the nozzle. A return spring in the cavity is biased against the face of the valve guide. The valve guide is sealed to the cavity to isolate the return spring from the fluid in the dispensing chamber. When the trigger is squeezed, it forces the poppet valve to move in the chamber to force fluid into the dispensing chamber to, in turn, force the fluid out through the discharge passages. This movement of the poppet valve also causes the valve guide to move against the bias of the return spring. When pressure is released from the trigger, the return spring forces the valve guide and poppet valve back to the normal position. There is no contact between the fluid and any parts of the spray gun other than parts made of chemically inert materials. The return spring, being made of metal, is isolated from the fluid to eliminate any contamination from possible chemical reactions.