Fire alarm box with direct and scattered light detection and gas-sensitive layers

US6479833B1 · kind B1 · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Anton Pfefferseder · Oberhaching, DE
• Andreas Hensel · Egmating, DE

Key dates

• Filing date: Apr 6, 2001
• Grant date: Nov 12, 2002
• Expiry date: Apr 6, 2021

Classification

• Technology area (CPC G): Physics
• CPC primary: G08B17/113
• WIPO field: Control
• WIPO sector: Instruments

Abstract

A fire detector for detecting gaseous and dust-like combustion products, having at least one optical transmitter and at least two optical receivers for in each case outputting an electrical signal to a downstream evaluation unit. At least one of the optical receivers is disposed outside of a direct radiation range of the optical transmitter and acts as a scattered-light receiver, and a gas-sensitive layer is interposed in advance of at least one further optical receiver disposed in a direct radiation range of the optical transmitter this layer preferably absorbing light components of a specific narrow wavelength range in response to a contact with a specific gas.