Apparatus for monitoring disturbances in environmental conditions

• US 4,668,939 A
• Filed: 04/21/1986
• Issued: 05/26/1987
• Est. Priority Date: 08/27/1982
• Status: Expired due to Term

• Current Assignee: Nittan Co. Ltd. (Old) (Secom Company Limited)
• Original Assignee: Nittan Co. Ltd. (Old) (Secom Company Limited)
• Inventors: Tanaka, Seiichi, Kimura, Tetsuo
• Primary Examiner(s): Crosland, Donnie L.
• Application Number:
  US06/854,160
• Time in Patent Office: 400 Days
• Field of Search: 340/521, 340/518, 340/517, 340/506, 340/505, 340/511, 340/514, 340/524, 340/525, 340/660, 340/661, 340/825.06-825.13, 340/825.54, 340/825.55
• US Class Current: 340/521
• CPC Class Codes: G08B 26/002 only replying the state of the sensor

Abstract

An improved apparatus for detecting environmental disturbances such as the occurrence of a fire, a gas leak or the like, includes a central processing unit and a plurality of terminal detectors, wherein an identification code is assigned to each of the detectors and the central processing unit sequentially calls the detectors in rotation requesting them to transmit thereto the data collected on smoke concentration, gas concentration, temperature or the like. The apparatus is provided with a display unit and a memory. Data collected by each detector concerning on the environmental condition of the place where each detector is installed are stored in the memory in time series. When a signal for data exceeding a fixed reference level is received, a provisional alarm is raised for the operator and the stored data for a limited period of time in the past are displayed. The operator, upon noticing the alarm, reads the displayed data and judges whether a disturbance, a fire for instance, has occurred basing his judgment on his interpretation of the pattern of the past data in the light of the specific characteristics of said detector and the place where the detector is installed, and, when he judges that a disturbance has occurred, he manually issues a general alarm.

Claims

1. In an apparatus for detecting environmental disturbances such as the occurrence of a fire, a gas leak or the like comprising a central processing unit and a plurality of terminal detectors, wherein an identification code is assigned to each of the detectors and the central processing unit sequentially calls the detectors in rotation requesting them to transmit thereto the data collected on a specific environmental condition such as smoke concentration, gas concentration, temperature or the like,

the improved apparatus provided with

a memory connected to the central processing unit in which memory data on the detected condition which have been transmitted from the detectors over a limited period of time can be stored for each detector, and

a display unit which can display the data for the limited period stored in the memory,

whereby the central processing unit compares the fresh data transmitted from each detector with a single fixed reference level and causes the display unit to display the data which have been transmitted from said detector and have been stored in the memory in a past limited period of time when said fresh data exceeds the reference level.

2. An apparatus for detecting environmental disturbances as claimed in claim 1, which can display the data stored in a past limited period of time for the detectors other than the detector which transmitted the signal exceeding the reference level.

3. An apparatus for detecting environmental disturbances as claimed in claim 1, which can store and display the data which have been collected by a detector after said detector transmitted a signal exceeding the reference level.

4. An apparatus for detecting environmental disturbances as claimed in any one of claims 1 through 3, which can issue a provisional alarm when a signal exceeding the reference level is received by the CPU.

5. An apparatus for detecting environmental disturbances as claimed in any one of claims 1 through 3, which can set a reference level which is lower than the normal reference level for the disturbance to be detected.

6. An apparatus for detecting environmental disturbances as claimed in any one of claims 1 through 3, wherein the detector comprises a sensor selected from a smoke sensor, a gas sensor and heat sensor.