Fire alarm system, sensor and method

• US 4,871,999 A
• Filed: 05/18/1987
• Issued: 10/03/1989
• Est. Priority Date: 05/19/1986
• Status: Expired due to Fees

• Current Assignee: Hochiki Kabushiki Kaisha
• Original Assignee: Hochiki Kabushiki Kaisha
• Inventors: Ono, Takashi, Ishii, Hiromitsu
• Primary Examiner(s): Swann, III, Glen R.
• Assistant Examiner(s): MULLEN, THOMAS J
• Application Number:
  US07/051,576
• Time in Patent Office: 869 Days
• Field of Search: 340/587, 340/584, 340/511, 340/628-630, 356/439, 374/169, 374/172, 219/489
• US Class Current: 340/587
• CPC Class Codes: G08B 17/00 Fire alarms; Alarms responsive to explosion

Abstract

A fire alarm system, sensor and method for determining a fire by detecting a change in a temperature, smoke density and/or gas concentration due to a fire. The detection data values of the respective analog sensors are corrected based on areas of supervisory regions of the respective analog sensors which are defined by walls, beams or inwardly extending projections surrounding the respective analog sensors, and/or heights from the floor of the respective analog sensors. The fire determination is carried out based on the corrected data.

Claims

1. A fire alarm system comprising:

a plurality of analog sensors for detecting a change in ambient conditions caused by a fire;

a correcting means for providing correct data from the respective analog sensors on the basis of set supervisory regions for the respective analog sensors which are defined by walls, beams or inwardly extending projections surrounding the respective analog sensors; and

a fire determining means for carrying out fire determination based on the correct data provided by said correcting means.

2. A fire alarm system according to claim 1, wherein said correct means determines the correcting data based on heights of the respective analog sensors from a floor as well as the volume of the supervisory regions.

3. A fire alarm system according to claim 2, wherein said correcting means comprises:

a first correction coefficient setting section or storing correction coefficients to be selected according to the supervisory regions set for the respective analog sensors and outputting the correction coefficient corresponding to the analog sensor being processed;

said correction coefficients being variable and being storable variably by said setting section;

a second correction coefficient setting section for storing correction coefficients to be selected according to installation heights set for the respective analog sensors and outputting the correction coefficient corresponding to the analog sensor being processed;

said correction coefficients to be selected according to the installation heights being variable and being storable variably by said second setting section; and

a correction calculating section for calculating correct data from the first and the second correction coefficient outputs from the first and the second correction coefficient setting sections and input analog data.

4. A fire alarm system according to claim 3, wherein threshold values to be selected according to the supervisory regions and sensor installation heights each set for the respective analog sensors are insertable into said correcting means, said correcting means storing the threshold values and having an output for the threshold value corresponding to the analog sensor being processed.

5. A fire alarm system according to claim 1, wherein said correcting means comprises:

a correction coefficient setting section for receiving correction coefficients to be selected according to the supervisory regions set for the respective analog sensors, said setting section storing the correction coefficients and outputting the correction coefficient corresponding to the analog sensor being processed;

said analog sensors receiving input analog data;

said correction coefficients being variable and being storable variably by said setting section; and

a correction calculating section for calculating correct data from the correction coefficient output from said correction coefficient setting section and the input analog data.

6. A fire alarm system according to claim 1, wherein said correcting means utilizes. as said correct data, threshold values for detection data from the respective analog sensors which are determined by the supervisory regions.

7. A fire alarm system according to claim 6, wherein threshold values to be selected according to the supervisory regions set for the respective analog sensors are insertable into said correcting means, said correcting means storing the threshold values and having an output for the threshold value corresponding to the analog sensor being processed said threshold values being variable and being storage variably by said correcting means.

8. A fire alarm sensor comprising:

an analog sensor section for detecting a change in ambient conditions caused by a fire;

a correcting section for providing correct data from the analog sensor section on the basis of a set supervisory region for the analog sensor section which is defined by walls, beam or inwardly extending projections surrounding the analog sensor section; and

a fire determining section for carrying out fire determination based on the correct data provided by said correcting section.

9. A fire alarm sensor according to claim 8, wherein said correcting section determines said correct data based on height of the respective analog sensor from a floor.

10. A fire alarm sensor according to claim 9, wherein said correcting section comprises:

a first correction coefficient setting section for storing a correction coefficient to be selected according to the supervisory region set for the analog sensor section and outputting the correction coefficient;

said correction coefficient being variable and being storable variably by said first setting section;

a second correction coefficient setting section for storing a correction coefficient to be selected according to an installation height set for the analog sensor section and outputting the correction coefficient;

said correction coefficient to be selected according to the installation height being variable and being storable variably by said second setting section, said analog sensor section receiving input analog data; and

a correction calculating section for calculating correct data from a first and a second correction coefficient output from said first and the second correction coefficient setting section and input analog data from the analog sensor section.

11. A fire alarm sensor according to claim 10, wherein a threshold value to be selected according to the supervisory region and sensor installation height each set for the analog sensor section are insertable into said correcting section, said correcting section storing the threshold value and outputting the threshold value corresponding to the analog sensor being processed;

said threshold value being variable and being storable variable by said correcting section.

12. A fire alarm sensor according to claim 8, wherein said correcting section comprises:

a correction coefficient setting section for receiving a correction coefficient to be selected according to the supervisory region, said setting section storing the correction coefficient and outputting the correction coefficient, said correction coefficient being variable and being storage variably by said setting section;

said analog sensor section receiving input analog data; and

a correction calculating section for calculating correct data from the correction coefficient output from said correction coefficient setting section and the input analog data from said analog sensor section.

13. A fire alarm sensor according to claim 8, wherein said correcting section utilizes, as said correct data, a threshold value for detection data from the analog sensor which is determined by the supervisory region.

14. A fire alarm sensor according to claim 13, wherein the threshold value to be selected according to the supervisory region set for the analog sensor section is insertable into said correcting section, said correcting section storing the threshold value and outputting the threshold value;

said threshold value being variable and being storable variably by said correcting section.

15. A fire alarm method operative in a fire alarm system or in a fire alarm sensor adapted to detect a change in ambient conditions caused by a fire, through a plurality of analog sensors, or in a single fire detector, said method comprises steps of:

determining correct data for detection data from the respective analog sensors based on supervisory regions for the respective analog sensors which are defined by walls, beams or inwardly extending projections surrounding the respective analog sensors; and

carrying out fire determination based on the correct data determined by said step of determining correct data.

16. A fire alarm method according to claim 15, wherein said correct data is determined based on heights of the respective analog sensors from a floor.

17. A fire alarm method according to claim 16, wherein said step of determining correct data comprises:

setting a first correct coefficient section for outputting correction coefficients to be selected according to the supervisory regions set for the respective analog sensors so as to correspond to the analog sensors being processed, respectively;

setting a second correction coefficient section for outputting correction coefficients to be selected according to installation heights set for the respective analog sensors so as to correspond to the analog sensors being processed, respectively;

said analog sensors receiving input analog data; and

calculating correct data from the correction coefficient and the input analog data.

18. A fire alarm method according to claim 17, wherein said step of determining correct data outputs threshold values to be selected based on installation heights of the respective analog sensors so as to correspond to the analog sensors being processed, respectively.

19. A fire alarm method according to claim 15, wherein said step of determining correct data comprises:

setting a correction coefficient section for outputting correction coefficients to be selected according to the supervisory regions set for the respective analog sensors so as to correspond them to the analog sensors being processed, respectively;

said analog sensors receiving input analog data;

calculating correct data from the output correction coefficient and the input analog data.

20. A fire alarm method according to claim 15, wherein said step of determining correct data utilizes, as said correct data, threshold values for detection data from the respective analog sensors which are determined by the supervisory regions.

21. A fire alarm method according to claim 20, wherein said step of determining correct data outputs threshold values to be selected based on the supervisory regions for the respective analog sensors so as to correspond to the analog sensors being processed, respectively.