Fire monitoring system and fire sensor

• US 6,204,768 B1
• Filed: 10/26/1999
• Issued: 03/20/2001
• Est. Priority Date: 10/30/1998
• Status: Expired due to Term

• Current Assignee: Hochiki Corporation
• Original Assignee: Hochiki Corporation
• Inventors: Kosugi, Naoki, Ito, Masayuki
• Primary Examiner(s): Lee, Benjamin C.
• Assistant Examiner(s): Previl, Daniel
• Application Number:
  US09/427,070
• Time in Patent Office: 511 Days
• Field of Search: 340/506, 340/505, 340/508, 340/511, 340/517, 340/521, 340/522, 340/523, 340/577, 340/584, 340/628, 340/632, 340/286.01, 340/286.02
• US Class Current: 340/577
• CPC Class Codes: G08B 17/00 Fire alarms; Alarms responsive to explosion
• CPC Class Codes: G08B 17/113 Constructional details
• CPC Class Codes: G08B 26/001 with individual interrogation of substations connected in parallel

Abstract

A multi-sensor type sensor has sensor processors for generating detection data of plural types based on detection signals from a plurality of sensor portions, and a mode switching portion for switching a mode which indicates type of data to be sent to a receiver in response to a mode switching instruction issued from the receiver, and sending selectively the data of the type which corresponds to a current switching mode in response to a data request instruction issued from the receiver. The receiver includes a mode switching indicating portion for switching the mode by transmitting the mode switching instruction which selects type of response data to the fire sensors, and a fire judging portion for judging the fire by receiving the response data from the fire sensors in response to transmission of the data request instruction.

Claims

1. A fire monitoring system capable of detecting a fire by connecting a plurality of fire sensors to a receiver via a transmission line and then transmitting detection data from the plurality of fire sensors repeatedly in predetermined order in response to respective instructions issued from the receiver;

wherein each of the fire sensors comprises;

a plurality of sensor portions of different types;

sensor processors for outputting detection data of plural types, based on detection signals from the plurality of sensor portions; and

a mode switching portion for switching a mode which corresponds to responding detection data in response to a mode switching instruction issued from the receiver, and sending selectively the detection data which corresponds to a current switched mode in response to a data request instruction issued from the receiver; and

wherein the receiver comprises;

a mode switching indicating portion for switching the mode by transmitting the mode switching instruction which selects the mode of the detection data to the fire sensors, and

a fire judging portion for judging the fire by receiving the detection data which is sent from the fire sensors in response to transmission of the data request instruction;

wherein said plural types of detection data include multi-sensor data which is corrected detection data from one of said plurality of sensor portions based on detection data from a remainder of the plurality of sensor portions.

2. The fire monitoring system according to claim 1, wherein the mode switching indicating portion of the receiver switches the mode of a particular fire sensor by designating the address of the particular fire sensor.

3. The fire monitoring system according to claim 1, wherein the mode switching indicating portion of the receiver switches the mode of all fire sensors by designating a polling address common to all fire sensors.

4. The fire monitoring system according to claim 1, wherein the mode switching indicating portion of the receiver switches a current mode which has fault into the other normal modes when it detects the fault in each of the fire sensors.

5. A fire monitoring system capable of detecting a fire by connecting a plurality of fire sensors to a receiver via a transmission line and then transmitting detection data from the plurality of fire sensors repeatedly in predetermined order in response to respective instructions issued from the receiver;

wherein each of the fire sensors comprises;

a plurality of sensor portions of different types;

sensor processors for outputting detection data of plural types, based on detection signals from the plurality of sensor portions; and

a mode switching portion for switching a mode which corresponds to responding detection data in response to a mode switching instruction issued from the receiver, and sending selectively the detection data which corresponds to a current switched mode in response to a data request instruction issued from the receiver; and

wherein the receiver comprises;

a mode switching indicating portion for switching the mode by transmitting the mode switching instruction which selects the mode of the detection data to the fire sensors, and

a fire judging portion for judging the fire by receiving the detection data which is sent from the fire sensors in response to transmission of the data request instruction;

wherein each of the fire sensors includes, as the plurality of sensor portions, a smoke sensor portion for detecting a smoke generated by the fire to output a smoke signal, and a heat sensor portion for detecting heat radiated by the fire to output a temperature signal;

each of the fire sensors includes, as the sensor processors, a smoke sensor data processor for converting the smoke signal into smoke data responding to the receiver and then holding the smoke data, a temperature sensor data processor for converting the temperature signal into temperature data responding to the receiver and then holding the temperature data, and a multi-sensor data processor for correcting the smoke signal based on the temperature signal to convert the smoke signal into corrected smoke data responding to the receiver and then holding the corrected smoke data; and

the mode switching portion has switching functions of a smoke sensor mode to send the smoke data, a temperature sensor mode to send the temperature data and a multi-sensor mode to send the corrected smoke data, and then switches the mode into one of the smoke sensor mode, the temperature sensor mode and the multi-sensor mode based on the mode switching instruction issued from the receiver.

6. The fire monitoring system according to claim 5, wherein the mode switching portion of each of the fire sensors sends data corresponding to a current switching mode when it receives the data request instruction not designating a particular mode from the receiver.

7. The fire monitoring system according to claim 5, wherein the mode switching portion of each of the fire sensors sends data in a designated mode irrespective of the current switching mode when it receives the data request instruction designating the particular mode from the receiver.

8. The fire monitoring system according to claim 5, wherein the mode switching portion of each of the fire sensors initializes the multi-sensor mode when the power supply is turned on.

9. The fire monitoring system according to claim 5, wherein each of the fire sensors further comprises an interruption processor for transmitting an interruption signal to the receiver when the smoke data, the temperature data or the corrected smoke data exceeds a predetermined threshold value;

and

the fire judging portion of the receiver transmits an interruption retrieval instruction so as to retrieve each of the fire sensors which has transmitted an interruption signal when it receives an interruption signal from each of the fire sensors and collects detection data sequentially by sending the data request instruction to a retrieved fire sensor repeatedly.

10. The fire monitoring system according to claim 5, wherein the multi-sensor data processor of each of the fire sensors includes:

a temperature difference detecting portion for detecting a temperature difference which represents a rate of temperature rise when it receives heat generated by the fire;

a correction factor deciding portion for deciding a correction factor for the smoke signal based on the external temperature and the temperature difference; and

a smoke signal correcting portion for correcting the smoke signal by multiplying the smoke signal by the correction factor.

11. The fire monitoring system according to claim 10, wherein the correction factor deciding portion of the multi-sensor processing portion divides the external temperature and the temperature difference into a plurality of temperature ranges each having a predetermined temperature width respectively, then previously sets the correction factor to each temperature range of the temperature difference so as to increase substantially in proportion to an increase of the temperature difference if the external temperature belongs to a same temperature range, then previously sets the correction factor to each temperature range of the external temperature so as to increase substantially in proportion to rise of the external temperature if the temperature difference belongs to a same temperature range, and then decides a previously set correction factor based on the temperature range to which the external temperature detected by the external temperature detecting portion belongs and the temperature range to which the temperature difference calculated by the temperature difference calculating portion belongs.

12. The fire monitoring system according to claim 11, wherein the correction factor deciding portion of the multi-sensor processing portion varies the correction factor substantially by changing the temperature range of the external temperature and/or the temperature range of the temperature difference while fixing the previously set correction factor itself, otherwise varies the correction factor itself while fixing the temperature range of the external temperature and the temperature range of the temperature difference.

13. The fire monitoring system according to claim 11, wherein the correction factor deciding portion of the multi-sensor processing portion decides the correction factor of 1.0 and does not substantially correct the smoke signal by the smoke signal correcting portion if the external temperature is below a first predetermined temperature, if the temperature difference is below a first predetermined temperature difference, or if the external temperature is more than a second predetermined temperature and the temperature difference is less than a second predetermined temperature difference.

14. A fire sensor which is connected to a receiver via a transmission line and transmits detection data in response to an instruction issued from the receiver, comprising:

a plurality of sensor portions of different types;

a sensor processor for generating plural types of data based on the detection data from the plurality of sensor portions; and

a mode switching portion for switching a mode which corresponds to the detection data in response to the receiver according to a mode switching instruction from the receiver, and sending selectively the data which corresponds to a current switching mode according to a data request instruction from the receiver;

wherein said plural types of data include multi-sensor data which is corrected detection data from one of said plurality of sensor portions based on detection data from a remainder of the plurality of sensor portions.