Abstract: A range hood positioned above a cooking range employs a continuous heat sensor system which includes twisted wires which are separated from one another by an insulator which is formed of a material which melts at a predetermined temperature. The wires carry a supervisory current which also flows through an actuator, which may be an electrified system for cutting a tension wire. An indicator lamp, such as an LED, which may have a series resistor associated therewith, limits the current through the actuator to a level below the activation threshold of the actuator.

Abstract: A range hood positioned above a cooking range employs a continuous heat sensor system which includes twisted wires which are separated from one another by an insulator which is formed of a material which melts at a predetermined temperature. The wires carry a supervisory current which is monitored continuously. When the magnitude of the current is increased, such as by the creation of a short-circuit condition as would be caused by the presence of a fire, an actuation signal is issued to an actuator, which may include an explosive squib. The explosive squib releases a tension wire which holds a discharge valve in a closed position, permitting a fire suppressant fluid to be discharged from a supply tank. Monitor circuitry ensures that open-circuit or short-circuit faults do not disable the functioning of the actuation system. Multi-condition fault indicators alert the user visually and audibly of system faults.

Abstract: A range hood positioned above a cooking range employs a continuous heat sensor system which includes twisted wires which are separated from one another by an insulator which is formed of a material which melts at a predetermined temperature. The wires carry a supervisory current which also flows through an actuator, which may be an electrified system for cutting a tension wire. An indicator lamp, such as an LED, which may have a series resistor associated therewith, limits the current through the actuator to a level below the activation threshold of the actuator.

Abstract: A check system for a chemical fire extinguisher utilizes a normally-closed check valve to prevent escape of pressurized chemical during periodic maintenance of a pressure monitoring system, such as a pressure gauge. An actuator member which is disposed within the flow channel of the fire extinguisher system is used to apply a force to the check system whereby a normally-closed check valve is urged to its open state. This open state establishes communication between the interior of the pressurized tank and the pressure monitoring system. Removal, or loosening, of a coupler, or union, which secures the pressure monitoring system to the chemical tank, permits the check valve to return to its normally-closed state. Thus, the pressure monitoring system can be removed and serviced periodically without requiring the pressurized tank to be emptied.