Abstract: Hydrogen in a fuel cell is vented and purged with a fail-closed valve using stored energy (e.g. from a capacitor) when a diagnostic parameter is outside of an acceptable operating range. The valve closes after the stored energy has depleted. A safety switch in the relay circuit of the solenoid switch (or solenoid valve) is also grounded in computer-implemented shutdowns. Benefits from the invention include use of air-compatible catalysts, minimized parasitic losses to power output, minimized contamination of fuel cell internal surfaces after venting, minimized risk of explosive mixture buildup, and efficient operation.

Abstract: Hydrogen in a fuel cell is vented and purged with a fail-closed valve using stored energy (e.g. from a capacitor) when a diagnostic parameter is outside of an acceptable operating range. The valve closes after the stored energy has depleted. A safety switch in the relay circuit of the solenoid switch (or solenoid valve) is also grounded in computer-implemented shutdowns. Benefits from the invention include use of air-compatible catalysts, minimized parasitic losses to power output, minimized contamination of fuel cell internal surfaces after venting, minimized risk of explosive mixture buildup, and efficient operation.

Abstract: A machine for making mop heads includes a pair of parallel forward moving conveyor chains and a yarn winder upstream of the conveyor chains. A continuous supply of yarn is wound by the winder around the outside of the conveyor chains as the chains are moving forward. Downstream of the winder, two rolls of fabric apply a narrow strip of fabric to the yarn at opposite ends inside the conveyor chains. A pair of sewing machines stitch the fabric to the yarn to form opposite end loops around the conveyor chains. Periodically, the winder is stopped or slowed while the conveyor chains continue to move forward forming a long angled loop in the yarn dividing groups of yarn loops. A centrally located taping device sequentially encircles each group of yarn loops at a point equidistant between the conveyor chains. Downstream of the conveyor chains, a pair of rotating arms collect individual taped and stitched groups of yarn loops and a cutter cuts the fabric strips and yarn between each bunched group.