Analog fire detector and analog fire alarm system using the same

• US 4,749,987 A
• Filed: 04/04/1986
• Issued: 06/07/1988
• Est. Priority Date: 04/09/1985
• Status: Expired due to Term

• Current Assignee: Hochiki Kabushiki Kaisha
• Original Assignee: Hochiki Corporation
• Inventors: Ishii, Hiromitsu
• Primary Examiner(s): Orsino, Joseph A.
• Assistant Examiner(s): MULLEN, THOMAS J
• Application Number:
  US06/848,726
• Time in Patent Office: 795 Days
• Field of Search: 340/587, 340/578, 340/511, 364/178, 364/551, 364/557
• US Class Current: 340/587
• CPC Class Codes: G08B 17/00 Fire alarms; Alarms responsive to explosion

Abstract

An analog fire detector which comprises sensor means for detecting, in analog form, one or more kinds of quantity of state which change due to fire; a sampling means for sampling the detection outputs from the sensor means with a predetermined period; and fire determining means which predicts future fire data changes from the sampling data and generates a fire determination output signal when the prediction data satisfies predetermined fire conditions. The invention also provides an analog fire alarm system which comprises a central signal station; a plurality of on-off type fire detectors connected to a pair of power supply/signal lines connected to said central signal station in such a manner that the signal lines are short-circuited into low impedance when the value of a quantity of state changed due to a fire exceeds a threshold value; and an intelligent fire detector installed in specific areas, where the signal lines are extended, such as an important supervisory area or an area where a false alarm is liable to occur, and adapted to short-circuit the signal lines into low impedance when a predicted value of a future quantity of state changing due to a fire satisfies predetermined fire conditions; such intelligent fire detector being the analog fire detector mentioned above.

Claims

1. An analog fire detector which comprises:

sensor means for detecting, in analog form, one or more kinds of quantity of state, which will change due to a fire;

sampling means for sampling the detection outputs from the sensor means with a predetermined period; and

fire determining means which predicts future fire data changes from the sampling data and generates a fire determination output signal when the prediction data satisfies predetermined fire conditions.

2. An analog fire detector as claimed in claim 1, wherein said fire determining means predicts a change of the fire data by functional approximation.

3. An analog fire detector as claimed in claim 2, which further comprises a data transmission control means which inhibits transmission of the sampling data to said fire determining means when said data is lower than a predetermined value and allows transmission of said data to said fire determining means when said data exceeds said predetermined value.

4. An analog detector as claimed in claim 3, which further comprises an average calculating means for carrying out average calculation and wherein said fire determining means predicts a change of the fire data on the basis of the average calculation data.

5. An analog fire detector as claimed in claim 4, which is connected between a pair of power supply/signal lines and which further comprises a fire signal outputting section circuit adapted to produce a short-circuit between the signal lines on the basis of the output signal from the fire determining means for transmitting such signal.

6. An analog fire detector as claimed in claim 5, which further comprises a unique signal transmitting section for transmitting, through the signal lines, a unique signal having a frequency preliminarily allotted or an address signal when the fire signal outputting section produces an output signal.

7. An analog fire detector as claimed in claim 3, in which a calculation starting level is provided for the fire determination carried out by the fire determining means.

8. An analog fire detector as claimed in claim 3, in which the predetermined value of the sampling data is a sensor threshold level which provides noise reduction.

9. An analog fire detector as claimed in claim 3, in which a calculation starting level is provided for the fire determination carried out by the fire determining means and the predetermined value of the sampling data is a sensor threshold level which provides noise reduction.

10. An analog fire detector as claimed in claim 9, which further comprises an average calculating means for carrying out average calculation and wherein said fire determining means predicts a change of the fire data on the basis of the average calculation data.

11. An analog fire detector as claimed in claim 10, which is connected between a pair of power supply/signal lines and which further comprises a fire signal outputting section circuit adapted to produce a short-circuit between the signal lines on the basis of the output signal from the fire determining means for transmitting such signal.

12. An analog fire detector as claimed in claim 11, which further comprises a unique signal transmitting section for transmitting, through the signal lines, a unique signal having a frequency preliminarily allotted or an address signal when the fire signal outputting section produces an output signal.

13. An analog fire detector as claimed in claim 2, wherein said fire determining means further comprises a vector predictive calculating section for predicting future fire data from the vector formed by a plurality of kinds of sampling data and a vector determining section adapted to generate a fire determination output when the predicted vector data exceeds a predetermined level preliminarily set in a given dimensional vector space.

14. A fire alarm system which comprises:

a central signal station; and

a plurality of analog fire detectors connected to a pair of power supply/signal lines connected to said central signal station;

said analog fire detectors each comprising

sensor means for detecting, in analog form, one or more kinds of quantity of state which change due to a fire;

sampling means for sampling the detection outputs from the sensor means with a predetermined period; and

fire determining means which predicts future fire data changes from the sampling data and generates

a fire determination output when the prediction data satisfies predetermined fire conditions.

15. A fire alarm system which comprises:

a central signal station;

a plurality of on-off type fire detectors connected to a pair of power supply/signal lines derived from said central signal station in such a manner that the signal lines are short-circuited into low impedance when the value of a quantity of state which changes due to a fire exceeds a threshold value; and

an intelligent fire detector installed in specific areas where the signal lines are extended, such as an important supervisory area or an area where a false alarming is liable to occur, and adapted to short-circuit said lines into low impedance when a predicted value of a future quantity of state changing due to a fire satisfies predetermined fire conditions;

said intelligent fire detector including one or more sensor means for detecting, in analog form, one or more kinds of quantity of state which will change due to a fire;

sampling means for sampling the detection outputs from the sensor means with a predetermined period;

fire determining means which predicts future fire data changes from the sampling data and generates a fire determination output signal when the prediction data satisfies predetermined fire conditions; and

a fire signal outputting section for short-circuiting said power supply/signal lines into low impedance on the basis of the fire determination output signal.

16. A fire alarm system as claimed in claim 15, wherein said fire determining means of the intelligent fire detector predicts a change of fire data by the functional approximation.

17. A fire alarm system as claimed in claim 16, wherein said intelligent fire detector further comprises a data transmission control means which inhibits transmission of the sampling data to said fire determining means when said data is lower than a predetermined value and allows transmission of said data to said fire determining means when said data exceeds said predetermined value.

18. An analog fire detector as claimed in claim 17, in which a calculation starting level is provided for the fire determination carried out by the fire determining means.

19. An analog fire detector as claimed in claim 17, in which the predetermined value of the sampling data is a sensor threshold level which being defined for noise reduction.

20. An analog fire detector as claimed in claim 17, in which a calculation starting level is provided for the fire determination carried out by the fire determining means and the predetermined value of the sampling data is a sensor threshold level which provides noise reduction.

21. A fire alarm system as claimed in claim 20, wherein said intelligent fire detector further comprises an average calculating means for carrying out average calculation and wherein said fire determining means predicts a change of the fire data on the basis of the average calculation data.

22. A fire alarm system as claimed in claim 16, wherein said fire determining means of said intelligent fire detector further comprises a vector predictive calculating section for predicting future fire data from the vector formed by the plurality of kinds of sampling data and a vector determining section adapted to generate a fire determination output when the predicted vector data exceeds a predetermined level preliminarily set in a given dimensional vector space.