Abstract: A surface breathing vent device for a mask permits the user wearing the mask to breathe ambient air prior to diving under water or entering an oxygen-poor environment and includes a support plate couplable to the mask and provided with an opening in alignment with the com port of the face mask, a bushing provided in the opening, and a vent barrel received in the bushing and movable between an open position in which ambient air can pass into the mask and a closed position where water is prevented from entering the mask. The barrel includes a closed end and two lateral openings which permit air to pass therethrough when the barrel is in the open position. A first O-ring prevents the inadvertent removal of the barrel from the bushing, a second O-ring functions as a detent when the barrel is opened and closed, and a third O-ring provides a water and air tight seal when the barrel is in a closed position.

Abstract: A manually operable control valve for a breathing apparatus to allow a user to alternate from a primary breathing gas supply to a secondary breathing gas supply. The manually operable control valve includes an elongated valve body and a linearly reciprocal shuttle valve. The valve body includes an axial passageway having a pair of spaced-apart inlet ports. The inlet ports each have an inner end opening onto the axial passageway and an outer end which connects to a separate gas supply. The valve body also has one outlet port having an inner end opening onto the axial passageway and an outer end connectable to the breathing apparatus. The linearly reciprocal shuttle valve is slidably mounted within the axial passageway for movement between a first end position in which it establishes fluid communication between the first inlet port and the outlet port and a second end position in which it establishes fluid communication between the second inlet port and the outlet port.

Abstract: A process and apparatus are provided for recovering metals from dilute solution utilizing ion exchange and, optionally, electrolytic recovery. Ammonium salt regeneration solutions for use in the process and apparatus are also provided. In one aspect, the invention provides a closed loop process and apparatus whereby metals may be recovered from spent electroplating rinse solutions for reuse in the electroplating bath with essentially no generation of waste.