LOW POWER DETECTION AND ALARM

• US 20150294546A1
• Filed: 11/19/2013
• Published: 10/15/2015
• Est. Priority Date: 11/20/2012
• Status: Active Grant

• Current Assignee: Sprue Safety Products Ltd. (FireAngel Safety Technology Group Plc)
• Original Assignee: Sprue Safety Products Ltd. (FireAngel Safety Technology Group Plc)
• Inventors: Brigham, Peter, Hart, Stuart
• Granted Patent: US 9,824,561 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G08B 17/10 Actuation by presence of smoke or gases , e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means
• CPC Class Codes: G08B 17/113 Constructional details
• CPC Class Codes: G08B 21/12 responsive to undesired emission of substances, e.g. pollution alarms
• CPC Class Codes: G08B 21/16 Combustible gas alarms
• CPC Class Codes: G08B 29/181 due to failing power supply

Abstract

This invention is an alarm apparatus (100) for detecting radiation and/or pollutants including smoke and carbon monoxide. The apparatus comprises an alarm circuit including detection means for detecting the radiation and/or pollutants and an audible alarm emitting device (102). A power supply circuit (A, B), connectable to an external AC power supply, supplies power the alarm circuit. A controller (60) operates the power supply circuit (A, B) in a first mode of operation in which it supplies current to the alarm circuit (52) at a first level less than that required to energise the audible alarm emitting device (102) and, in response to the detection of radiation and/or pollutants, operates the power supply (A, B) in a second mode of operation in which it supplies current to the alarm circuit (56) at a second level sufficient to energise the audible alarm emitting device (102).

Claims

1. An alarm apparatus for detecting radiation and/or pollutants including smoke and carbon monoxide, the apparatus comprising:

an alarm circuit including detection means for detecting said radiation and/or pollutants and an audible alarm emitting device;

a power supply circuit, connectable to an external AC power supply, that supplies power to said alarm circuit; and

a controller configured to operate the power supply circuit in a first mode of operation in which it supplies current to the alarm circuit at a first level less than that required to energise the audible alarm emitting device and, in response to the detection of said radiation and/or pollutants, to operate the power supply in a second mode of operation wherein it supplies current to the alarm circuit at a second level sufficient to energise the audible alarm emitting device.

2. The alarm apparatus according to claim 1 wherein the power supply circuit comprises a rectifier and a charge pump configured to reduce the voltage and increase the current from the rectifier.

3. The alarm apparatus according to claim 2 wherein the rectifier comprises a half wave rectifier.

4. The alarm apparatus according to claim 2 or claim 3 comprising means, controlled by the controller, for controlling the voltage charge on a capacitor of the rectifier between a first voltage in the first mode of operation and a second, higher voltage in the second mode of operation.

5. The alarm apparatus according to claim 4 wherein the means for controlling the voltage comprises a thyristor, and wherein:

the controller is configured to supply a trigger current to the gate of the thyristor in the first mode of operation; and

the controller is configured not to supply a trigger current to the gate of the thyristor in the second mode of operation.

6. The alarm apparatus circuit according to claim 2 wherein power to drive the alarm circuit is taken from the power supply downstream of the charge pump.

7. The alarm apparatus according to claim 2 wherein power to drive the alarm circuit is taken from the power supply from between the half wave rectifier and the charge pump.

8. The alarm apparatus according to claim 2 wherein said power supply circuit comprises means for reducing the current supplied to said rectifier to a level below that required to energise said alarm.

9. The alarm apparatus according to claim 8 wherein said means comprises a capacitance in a power supply line of said power supply circuit.

10. The alarm apparatus according to claim 9 wherein said capacitance comprises a plurality of capacitors in parallel.

11. The alarm apparatus according to claim 1 further comprising a battery for supplying power to said alarm circuit in the absence of AC power.

12. The alarm according to claim 11 further comprising a step up circuit for increasing the voltage from the battery.

13. A method of providing power to an alarm apparatus for detecting radiation and/or pollutants including smoke and carbon monoxide, the method comprising:

providing an alarm circuit including detection means for detecting said radiation and/or pollutants and an audible alarm emitting device;

providing a power supply circuit, connectable to an external AC power supply, for supplying power to said alarm circuit;

operating the power supply circuit in a first mode of operation in which it supplies current to the alarm circuit at a first level less than that required to energise the audible alarm emitting device and,

in response to the detection of said radiation and/or pollutants, operating the power supply in a second mode of operation wherein it supplies current to the alarm circuit at a second level sufficient to energise the audible alarm emitting device.

14. The method according to claim 13 wherein providing a power supply circuit comprises providing rectifier and a charge pump, and increasing the current output from said rectifier with said charge pump.

15. The method according to claim 14 further comprising controlling the voltage charge of a capacitor of the rectifier between a first voltage in the first mode of operation and a second, higher voltage in the second mode of operation.

16. The method according to claim 15 further comprising:

providing a thyristor, and supplying a trigger current to the gate of the thyristor in the first mode of operation, and not supplying a trigger current to the gate of the thyristor in the second mode of operation.

17. The method according to claim 13, the method further comprising reducing the current supplied to said rectifier to a level below that required to energise said alarm emitting device.

18. The method according to claim 17 further comprising, in the event of detection of radiation and/or pollutants, increasing the current in the charge pump to a level sufficient to energise said alarm emitting device.

19. The method according to claim 13 further comprising providing a battery for supplying power to said alarm circuit in the absence of AC power.

20. The method according to claim of 17 wherein providing an battery comprises providing a battery having a voltage output below that required to energise the alarm emitting device and wherein the method further comprises providing a step up circuit to increase the voltage from the battery.