Abstract: A fire or explosion detection system is disclosed for reliably discriminating between a hydrocarbon fire in an armored vehicle and other sources of radiant energy including explosion of an armor-piercing ammunition round without an accompanying hydrocarbon fire. Radiation detectors sensitive to radiation at 4.4 microns and 0.9 microns, respectively, each produce logic outputs if the viewed radiation intensity exceeds a predetermined relatively low threshold and, in the case of the 4.4 micron detector, is rising at least a predetermined rate or, in the case of the 0.9 micron detector, is not falling at more than a predetermined rate. The logic outputs are fed to a coincidence gate which produces a fire- or explosion-indicating output only if all of the outputs are received concurrently for at least a predetermined period of time. A third radiation detector, in combination with the 0.

Abstract: A tire pressure gage for integral mounting on the wheel of an aircraft tire is provided with failsafe features to reduce the likelihood of sudden tire pressure loss through catastrophic failure of the gage. A pressure relief valve vents the case when the threshold pressure is sensed to thereby preclude long-term pressurization of the case should a slow leak develop in the bourdon tube of the gage. A flow-actuated valve in the port leading from the tire to the bourdon tube, seals the tire against pressure loss through the gage when a fast leak is detected such as might occur upon rupture of the tube. The pressure relief valve includes an ejectable plug normally visible externally of the gage case, the presence or absence of the plug providing a positive indication of whether or not the gage case has been pressurized.

Abstract: A pressure gauge assembly for aircraft tires and the like having a helical coil bourdon tube sensor capable of indicating a pressure differential between a monitored source of pressure and a calibrated reference source of pressure. The reference pressure is applied to one surface of the bourdon tube coils while the monitored pressure is applied to the other surface of the coils. The resultant movement is a linear indication of any pressure differential. A valve assembly can be provided with the pressure gauge assembly to permit fluidic access to the monitored pressure. If the volume of the monitored pressure is variable such as an aircraft tire, the secondary source of calibrated pressure can be provided with a predetermined pressure relative to the normal tire pressure to compensate for any volumetric changes in the tire during operation. In an alternative embodiment, the bourdon tube can be used to monitor the pressure in a fire extinguisher for indicating any leaks.

Abstract: A temperature compensated pressure limited gauge is provided having a bourdon tube pressure sensing element. The coil is connected to a sealed cavity and has a predetermined quantity of fluid such as oil calibrated into the gauge. A solid cylinder or block of material is located within the cavity and has a relatively low volumetric thermal expansion characteristic relative to that of the fluid and of the gauge housing about the cavity. The dimensions of the block of material and housing cavity are such that their relative expansions are capable of compensating for any volumetric changes of the fluid throughout the applicable temperature range of the pressure gauge. Accordingly, a temperature compensation feature is provided that renders the pressure gauge independent of ambient thermal conditions. A fitting is included in the gauge to provide fluidic communication with the cavity.

Abstract: A temperature compensated pressure indicator adapted to be mounted within a pressure container includes a reservoir housing and housing member welded together to form a secondary pressure chamber. A bellows member is hermetically mounted within the secondary pressure chamber and communicates with the exterior pressure of the container. Mounted on the bellows member is a movable magnetic member adapted to slide on a hollow guide post as a result of any pressure differentials. A reed switch assembly is held stationary in the guide post by a pair of band springs. The switch assembly is electrically connected to a source of power and an external indicator such as a light. When the bellows member moves the magnetic member close to the switch assembly due to a pressure differential, the magnetic field closes the switch assembly to activate the light. The indicator is substantially non-responsive to wide variations in the ambient temperature.