Fire alarm system

• US 4,644,331 A
• Filed: 06/18/1985
• Issued: 02/17/1987
• Est. Priority Date: 06/29/1984
• Status: Expired due to Term

• Current Assignee: Hochiki Corporation
• Original Assignee: Hochiki Corporation
• Inventors: Matsushita, Eige, Nagashima, Tetsuya
• Primary Examiner(s): SWANN III, GLEN R
• Application Number:
  US06/746,116
• Time in Patent Office: 609 Days
• Field of Search: 340/587, 340/588, 340/577, 340/584, 340/628, 364/178, 364/551, 364/723, 364/734
• US Class Current: 340/587
• CPC Class Codes: G08B 29/18 Prevention or correction of operating errors G08B29/02, G08B29/12 take precedence

Abstract

The detection signals regarding the temperature or smoke concentration generated due to the fire are sampled. The sampled data is processed by being averaged. An occurrence of a fire is determined on the basis of the processed data, i.e. - the averaged data, after completion of the averaging processes. The detection signals which are used for the fire determined are obtained by performing a moving mean calculation of a plurality of sampled data as one group and/or by executing a simple mean calculation of a plurality of moving mean data as one group.

Claims

1. A fire alarm system comprising:

a detecting section for detecting and outputting an analog value corresponding to a change in a physical phenomenon of the ambient circumstances;

sampling means for sampling at a predetermined period the analog detection signal outputted from said detecting section;

data processing means for sequentially storing sampled data from said sampling means and for performing an averaging process of a plurality of said data stored as one group; and

an alarm means for discriminating a fire on the basis of averaged data from said data processing means and then generating a fire alarm.

2. A fire alarm system according to claim 1, wherein said data processing means has:

first memory means for sequentially storing a plurality of said sampled data; and

moving mean calculating means for calculating a moving mean of a plurality of said data stored as one group in said first memory means.

3. A fire alarm system according to claim 1, wherein said data processing means has:

first memory means for storing a plurality of said sampled data;

moving mean calculating means for calculating a moving mean of a plurality of said data stored as one group in said first memory means;

second memory means for storing a plurality of moving means for said moving mean calculating means; and

simple mean calculating means for calculating a simple mean of said plurality of moving means stored as one group in said second memory means.

4. A fire alarm system according to claim 1, wherein said data processing means has:

first memory means for storing a plurality of said sampled data;

moving mean calculating means for calculating a moving mean of a plurality of said data stored as one group in said first memory means;

second memory means for storing a plurality of moving means from said moving mean calculating means; and

another moving mean calculating means for calculating a moving mean of a plurality of said moving means stored as one group in said second memory means.

5. A fire alarm system according to claim 1, wherein said alarm means has fire discriminating means for calculating, from the present time averaged data from said data processing means, a time interval until a value of the averaged data would reach a predetermined threshold level and thereby determining the fire when said time interval calculated lies within a predetermined time.

6. A fire alarm system according to claim 1, wherein said alarm means has a fire discriminating means for determining that a fire has occurred when a detection level exceeds a threshold level after an expiration of a predetermined time period from the commencement of the processing of data on the basis of the averaged data from said data processing means.