Abstract: A mechanical pressure relief system for a pressurized operating system which is suitable for high purity applications. The pressure relief system utilizes a mechanical logic switch, operable at a set point pressure, in conjunction with a pressurized actuating fluid, completely separated from the processing fluid. The system further utilizes shuttle valves to provide an additional degree of safety, with the minimization of emission of potentially highly hazardous gases, when used in the pressure relief system to prevent further inflow and outflow of processing fluid. Diversion elements are activated, with the pressure logic switch at preselected pressures, for ingress into the system of an actuating fluid. The actuating fluid serves to open venting passageways and to close processing fluid passageways until excessive pressure is relieved. When normal pressure is attained, the pressure logic switch reverses with closing of venting passageways and opening of processing fluid passageways.

Abstract: An automatic switchover valve includes first and second regulator valves arranged to oppose each other axially in a single housing, and ducted in a parallel configuration within the housing. Each regulator valve includes an inlet port, a diaphragm poppet valve, and a common outlet port. Each regulator valve includes structure for adjusting the pressure setting of the diaphragm poppet valve. During operation, the poppet valve of the first regulator valve is selectively adjustable between a first setting providing a first pressure P.sub.1, and a second setting providing a second pressure P.sub.2 less than P.sub.1 by an amount equal to 2 p. The poppet valve of the second regulator valve is preset at a reference pressure P.sub.R wherein P.sub.1 >P.sub.R >P.sub.2, and P.sub.1 -p=P.sub.R =P.sub.2 +p, and wherein p is greater than or equal to the incremental pressure characteristic of the regulator poppet valves.

Abstract: A device is disclosed for performing gymnastic exercises or the like, comprising a geometrically regular body including a plurality of polygonally-shaped flat sides and a plurality of spaced handle means. The handle means are defined by at least two elongated spaced openings in the surface of the body which flank the intersection between two of the flat sides. These openings cooperate with at least the remaining portion of the surface intervening therebetween to define elongated graspable hand-holds at the facial intersections.