Abstract: A resettable fire detection device comprises in combination a rate of temperature rise sensor, an electronic fixed temperature sensor, and electronic circuitry connected to both circuits for producing an alarm signal if either sensor is activated and for maintaining the alarm signal once the device has been activated. This resettable fire detection device has many uses: specifically, it can be used as a replacement device for a smoke detector device commonly used on ships. In this case, the device draws a very low amperage for use on a parallel circuit common wih smoke detectors. In addition, a time delay circuit can be associated with each of the sensors to avoid false alarms and to accommodate certain environmental conditions. The resettable nature of both the fixed temperature and rate of rise temperatue sensor allows full testing of each device while allowing a remote reset signal to be used to reset the device. In a preferred form, the rate of temperature rise sensor is a mechanical arrangement.

Abstract: An improved fire detector vented to atmosphere, capable of closing or opening an alarm circuit on the happening of either two events, when the rate of rise of the temperature of the ambient atmosphere exceeds a predetermined prescribed rate of rise of temperature and when the temperature of the ambient atmosphere exceeds a predetermined fixed temperature, the detector being of the type comprising a base supporting a diaphragm enclosing a space between the base and diaphragm, a shell secured to the base enclosing the diaphragm, vent apertures through the base from the space between the diaphragm and shell, and between the diaphragm and base, to the back of the detector, and a fin for collecting heat from the ambient atmosphere. The vent aperture permits the spaces between the diaphragm and base, and shell and base to be vented to atmosphere under normal expansion and contraction of the ambient atmosphere.

Abstract: An improved fire detector appropriately vented to atmosphere is provided, the detector comprising a base supporting a diaphragm enclosing a space between the base and diaphragm, a shell secured to the base enclosing the diaphragm, and a fin for collecting heat from the ambient atmosphere, secured by a ferrule to the shell. A vent aperture is provided through the base from the space between the diaphragm and the base to the back of the detector and which detector is covered by a closure cap. The fin is secured to the shell by a ferrule by causing peripheral portions of the end of the ferrule proximate the central aperture of the fin through which the ferrule is inserted to be forced to be indented to cause metal from such peripheral portions to flow radially over portions of the fin.