Abstract: A respirator having a combination demand air regulator to provide air to the user on demand and an exhaust check valve. The regulator diaphragm, by its inward movement during inhalation, causes the exhalation valve to close while regulating the intake of supply air. Conversely, the regulator diaphragm, by its outward movement during exhalation, causes the exhalation valve to open while keeping the demand valve closed.

Abstract: A hand held apparatus for the vapor polishing of plastic surfaces by movement of the apparatus over a plastic surface to be polished includes a body portion defining a vaporizing chamber. A container for plastic solvent, such as methylene chloride, is mounted on one side of the body for flow of solvent into the chamber when the apparatus is positioned with the container disposed above the chamber, with the solvent flow being interrupted when the apparatus is inverted to dispose the container below the chamber. A thermostatically controlled electric heating element is disposed in the chamber for vaporizing the solvent. An open-end guide tube projects from the opposite side of the body and is in fluid communication with the chamber. The guide tube opens downwardly when the apparatus is positioned with the container disposed above the chamber for directing the vaporized solvent to the plastic surface to be polished.

Abstract: A Self-Contained Breathing Apparatus with automatic redundant fluid pressure controls and a facemask mounted low pressure warning device. The apparatus utilizes two stages of pressure regulation wherein the final stage is the demand regulator that delivers the breathing gas to the wearer. The first state includes a pair of pressure regulators connected in parallel with different outlet pressures, both of which reduce the pressure of the stored supply gas to pressures compatible with the second stage breathing demand regulator. A primary regulator in the first stage delivers a low output pressure to the second stage demand regulator. In the event of a "failure closed" condition of the primary regulator an automatic transfer valve switches on the backup regulator and communicates its slightly higher outlet pressure to the demand regulator.