Fire Detector

• US 20100243898A1
• Filed: 03/25/2010
• Published: 09/30/2010
• Est. Priority Date: 03/27/2009
• Status: Active Grant

• Current Assignee: Nohmi Bosai Limited (Secom Company Limited)
• Original Assignee: Nohmi Bosai Limited (Secom Company Limited)
• Inventors: Kato, Kenichi
• Granted Patent: US 8,294,895 B2
• Time in Patent Office: Days
• US Class Current: 250/338.500
• CPC Class Codes: G01N 21/3504 for analysing gases, e.g. multi-gas analysis
• CPC Class Codes: G01N 21/53 within a flowing fluid, e.g. smoke
• CPC Class Codes: G01N 2201/022 Casings
• CPC Class Codes: G01N 2201/0642 Light traps; baffles
• CPC Class Codes: G08B 17/107 for detecting light-scattering due to smoke
• CPC Class Codes: G08B 17/113 Constructional details

Abstract

Provided is a fire detector in which an element substrate can be easily removed from and mounted into an optical case. The fire detector includes: an optical case (21); an element substrate (31), on which a light-receiving element (12) is mounted, the element substrate (31) being provided in the optical case (21); a signal line (35) passing through an introduction portion of a peripheral wall (21a) of the optical case (21), the signal line (35) being connected to the element substrate (31); and an optical cover (30) for closing an opening of the optical case (21), in which the signal line (35) is inserted into a slit (37) which is open on an upper end surface (21f) of the introduction portion of the peripheral wall (21a).

Claims

1. A fire detector, comprising:

an optical case;

a light-receiving element provided in the optical case;

a received-light amplifying section for amplifying an output signal of the light-receiving element; and

a fire determination section for determining occurrence of a fire when a detection level obtained by A/D conversion of the amplified output signal is equal to or higher than a threshold value, wherein;

a signal line is connected to an element substrate on which the light-receiving element is mounted; and

the signal line passes through a slit formed through a peripheral wall of the optical case.

3. A fire detector according to claim 1, wherein a light-shielding wall is provided in a space for housing the signal line in the optical case between a position at which the element substrate is to be mounted and the slit.

5. A fire detector according to claim 1, wherein the slit obliquely intersects the peripheral wall.

2. A fire detector, comprising:

an optical case whose interior forms a dark box;

an air passage constituting a smoke detection portion, for letting a gas flow into the optical case;

a light-emitting element provided in the optical case;

a light-receiving element for receiving scattered light generated by scattering of light emitted from the light-emitting element by smoke particles present in the smoke detection portion;

a received-light amplifying circuit for amplifying an output signal of the light-receiving element; and

a fire determination section for determining occurrence of a fire when a detection level obtained by A/D conversion of the amplified output signal is equal to or higher than a threshold value, wherein;

a signal line is connected to an element substrate on which one of the light-emitting element and the light-receiving element is mounted; and

the signal line passes through a slit formed through a peripheral wall of the optical case.

4. A fire detector according to claim 2, wherein a light-shielding wall is provided in a space for housing the signal line in the optical case between a position at which the element substrate is to be mounted and the slit.

6. A fire detector according to claim 2, wherein the slit obliquely intersects the peripheral wall.

7. A fire detector, comprising:

an optical case;

a light-receiving element provided in the optical case;

a received-light amplifying section for amplifying an output signal of the light-receiving element; and

a fire determination section for determining occurrence of a fire when a detection level obtained by A/D conversion of the amplified output signal is equal to or higher than a threshold value, wherein;

an outer surface of the optical case has conductivity; and

a signal-line retaining portion for bringing a signal line connected to an element substrate, on which the light-receiving element is mounted, into contact with the outer surface is provided to the optical case.

9. A fire detector according to claim 7, wherein the signal-line retaining portion is provided to an optical cover mounted onto the optical case.

8. A fire detector, comprising:

an optical case whose interior forms a dark box;

an air passage constituting a smoke detection portion, for letting a gas flow into the optical case;

a light-emitting element provided in the optical case;

a light-receiving element for receiving scattered light generated by scattering of light emitted from the light-emitting element by smoke particles present in the smoke detection portion;

a received-light amplifying circuit for amplifying an output signal of the light-receiving element; and

a fire determination section for determining occurrence of a fire when a detection level obtained by A/D conversion of the amplified output signal is equal to or higher than a threshold value, wherein;

an outer surface of the optical case has conductivity; and

a signal-line retaining portion for bringing a signal line connected to an element substrate, on which the light-receiving element is mounted, into contact with the outer surface is provided to the optical case.

10. A fire detector according to claim 8, wherein the signal-line retaining portion is provided to an optical cover mounted onto the optical case.