Abstract: A temperature compensated pressure control device comprising switch means for supplying pressure to a pressurized zone to maintain a predetermined pressure therein, a first diaphragm responsive to depletion of the pressure in said pressurized zone to effect actuation of the switch means to supply the required pressure, a second diaphragm operable to predispose the first diaphragm for a change in temperature in said pressurized zone and sensing means for transmitting the change in temperature to said second diaphragm.

Abstract: A control device wherein the component parts comprising a switch or switches, expandable bellows and a kinematic train for transmitting expansion or contraction of the bellows to the switch or switches for actuating the same are removably contained in separate compartments in a fully-gasketed, weathertight enclosure, but are readily accessible in their respective chambers for adjustment, removal and replacement. The switch or switches are sealed within a hermetically-sealed receptacle within the enclosure and operation of the switch or switches is effected without breach of the receptacle by displacement of a flexibly displaceable portion of the wall of the receptacle. The kinematic train includes means for effecting displacement of the flexibly displaceable wall portion and may include a Belleville washer assembly to impart snap action to the kinematic train and to hold it in its operative and inoperative positions.

Abstract: An air flow transducer wherein the displacement of a diaphragm by a pressure differential at the opposite sides thereof is measured in terms of unit electrical resistance. The pressure differential is provided by supplying the air to the transducer through ports, one of which is in communication with one side of the diaphragm and the other of which is in communication with the opposite side of the diaphragm, and by providing a linear flow restrictor in the latter port which resists air flow in direct proportion to any increase in the air flow to thus produce a pressure drop from one side of the diaphragm to the other which is directly proportional to the increase in flow.

Abstract: An air pressure instrument embodying a base receptacle adapted to be mounted to an instrument panel and to be connected to air and electric lines at the panel and a plug-in receptacle containing a pressure-responsive element and switch operable thereby adapted by plugging into the base receptacle to automatically connect the pressure-responsive element to the pressure line and the switch to the electric line.

Abstract: A transducer wherein a brush arm is supported for pivotal movement of its distal end along a bank of terminals in a circuit where there is a common terminal and a bank of terminals by expansion and contraction of a bellows. Brushes at the proximal and distal ends of the brush arm are yieldably held engaged with the bank of terminals at the distal end and the common terminal at the proximal end for adding resistances to and removing resistances from the circuit in proportion to changes in pressure. The bellows is supported in a capsule for linear expansion and contraction and contains an open end for receiving, a plug mounting the circuit, brush arm, and linkage as a unit, into operative relation to the bellows, said linkage providing for converting the linear movement of the bellows to rotational movement of the brush arm and for adjustment of the range of movement of the brush arm along the bank of terminals.

Abstract: A monitor for maintaining an atmosphere of gaseous sulfur hexafluoride supplied to the chamber of an outdoor circuit breaker at a predetermined density, which is to be kept constant, comprising a switch or valve operable to connect the chamber to a source of gaseous sulfur hexafluoride at said density and to disconnect it therefrom and a sensing device comprising a constant volume tube in the chamber filled with gaseous sulfur hexafluoride at the same density as that in the chamber, a compressible bellows in the tube filled with oil, a pair of opposed cascaded bellows supporting an actuator in operable relation to the switch or valve so as to maintain the switch or valve in a neutral position for any change in ambient temperature and wherein a decrease in pressure within the chamber will cause the switch or valve to be operated to supply gas pressure to the chamber.