Abstract: A pressure relief mechanism seated within a wall of a pressure vessel features a novel flexible seal. The vessel pressure acts against both a spring and an internal valve pressure created by the flexible seal. The pressure relief mechanism can be designed to release over a wide range of critical vessel pressures due to the combination of the resistive spring force and the resistive internal pressure.

Abstract: A low silhouette oscillating platform upon which may be mounted a device or machine for throwing balls to a player or players for catching or batting practice. The oscillating platform allows the pitched balls to be distributed at random within any point of a specified arc. The platform may be permanently attached to the throwing device or attached by quick-disconnect latches, thereby allowing removal for storage. The platform may be left attached to the throwing device and not electrically activated for throwing or pitching to a fixed point.Two wheels are so affixed to the platform that, when required, they may be used to move or transport the entire assembly. The lower surface of the platform is smooth or padded to protect the surface upon which it is placed, which may be a smooth tennis court.

Abstract: A method and apparatus for measuring particulates contained in the exhaust gases from internal combustion engines which dilutes the exhaust gases with prefiltered and precooled air to produce a constant volume mixture which may be sampled for exhaust gas emissions as well as for particulates. After mixing of the exhaust gases and the pretreated air, sampling of the mixture by isokinetic probes produces a uniform sample of particulate matter which is collected on temperature controlled filters for analysis.