Abstract: A pressurized extinguishant release device with a rolling diaphragm includes a closed elongated sensor tube filled for example with 50% water and 50% ethylene glycol which terminates in an enclosure sealed by a circular head portion of the rolling diaphragm. On the other side of the head portion is a piston connected to a penetrator retained against the diaphragm by a shear pin. The penetrator is positioned above a brittle membrane which encloses a pressurized extinguishant. Heating of the liquid filled sensor tube to a certain temperature will cause a vapor pressure to push against the diaphragm head to cause the shear pin to fail propelling the penetrator into the membrane and thus allow the extinguishant to flow.

Abstract: A pneumatic pressure detector for use in an overheat or fire alarm system utilizes a known capillary type sensor tube which has absorbed in it a gas. Overheat or fire condition causes the gas to expand which then actuates an associated deformable diaphragm to close an electrical switch. To insure that the system pressure is maintained and no fault condition exists, the compact detector also uses a deformable diaphragm associated with an integrity switch which opens if the pressure falls below normal. Both of these diaphragms are juxtaposed to form the plenum to which the sensor tube is attached thereby saving weight and space.

Abstract: A modular alarm system includes a plurality of sensing devices, each of which is adapted to sense the presence or absence of a particular condition, specifically a fire or over heat condition (hereinafter referred to merely as a fire condition), and the presence or absence of a fault including a short circuit or open circuit. The system also includes a detector module for producing an equal plurality of identical logic output signals indicative of and in response to the presence of the particular condition being monitored at the various sensing devices and a single, identical logic output signal indicative of and in response to the presence of a fault at any of the sensing devices.

Abstract: A current source is formed utilizing a reference voltage which is impressed on an impedance connected to the input of an operational amplifier. A buffer amplifier is coupled between the output and the input of the operational amplifier to prevent interaction between a high impedance signal source and a low impedance load. A constant output current appears at the output of the buffer amplifier, connected to a first electronic switch. A second electronic switch is connected to the other side of the load. A pair of signals having unstable amplitude are connected to control the first and second electronic switches. When the second electronic switch is either continuously on or alternatively on and off with the first electronic switch, the constant current is directed through the load when the first electronic switch is actuated to the off or open position, and is directed by bypass the load, when the first electronic switch is actuated to the on or closed condition.

Abstract: A command signal is provided through a buffer amplifier to an exponential signal generator which provides an exponential signal envelope at the output thereof. The exponential signal envelope is coupled to an inverting unity gain amplifier for providing an inverse exponential signal envelope. The exponential and inverse exponential signal envelopes are coupled to an astable element which provides an output frequency having an amplitude related to the exponential signal envelopes. Means are included in the exponential signal generator for providing a predetermined decay time for the exponential signal envelopes. Means are included in the astable element for providing a predetermined frequency at the output of the astable element. Means are also included in the astable element for providing a common assymptote for the exponential and inverse exponential signal envelopes.