JPS6318239B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention uses a detector for smoke, gas, heat, radiation, etc., and uses the detector to detect danger and activate response devices such as alarms and fire extinguishers. Regarding prevention devices.

(Prior art) It is extremely dangerous to ignore the occurrence of a fire, a leak of propane gas, or a leak of radiation, etc., and leave it as it is. It is generally known that countermeasures can be taken.

However, in conventional systems, a detector is provided to detect the occurrence of such an accident, and when a detection signal from the detector exceeds a predetermined gain, a response device such as an alarm is activated. However, these accidents should not occur that often, and it takes many years and a lot of time from the time these devices are installed until an accident that requires their operation occurs. There is no point in installing these if they do not function properly even if they are old.

Over the years, dust has accumulated on the case enclosing the detector, which not only reduces its detection ability, but also causes the detector itself to age, or the electronics that amplify the detector's detection signal. As parts and the like age, the detection signal of the detector gradually decreases. However, if the response device were to operate only when the detection signal of the detector itself exceeds a predetermined gain, as in the past, it would become extremely unreliable as a danger prevention device.

In order to solve these problems, the special public
As shown in Publication No. 30088, in a device that identifies patterns based on signals from an imager such as a television camera, the signal from the imager is stored in a memory circuit, and this stored signal is directly compared with the signal from the imager. Some methods have been proposed to correct malfunctions caused by fluctuations in detection sensitivity over time, but when the physical quantity to be measured changes gradually, the difference between the stored value and the detected value is small, so it is necessary to lengthen the detection cycle. Either set it or
It is necessary to detect the difference extremely precisely, and if the former method is used, it will take time to output the judgment result, causing a warning delay, and if the latter method is used, drift etc. There is a problem that malfunctions may occur due to this.

(Objective of the Invention) The present invention has been made in view of these problems, and its purpose is to reliably detect changes in the physical quantity to be measured, regardless of changes in detector sensitivity over time. It is an object of the present invention to provide a novel detection and response device for smoke, gas, heat, radiation, etc., which can quickly detect and activate the response device.

(Summary of the Invention) That is, the present invention is characterized by a detector that outputs a detection signal for each oscillation pulse of a clock pulse oscillator, and a detector that outputs a detection signal sequentially over time under the control of the oscillation pulse of the clock pulse oscillator. a memory circuit having a plurality of memory areas that store data while updating one by one, an arithmetic circuit that calculates an average value of data in the plurality of memory areas, and a calculation circuit that calculates the average value and a detection signal from the detector using the clock pulse. By providing a comparison circuit that compares the two and outputs a signal when the comparison value exceeds the set value, even if there is a slight variation in the physical quantity to be measured, this variation can be integrated and compared. It is possible to obtain a large level comparison result and to operate quickly in response to sudden changes.

(Example) The details of the present invention will be described below based on illustrated examples.

The figure shows one embodiment of the present invention,
Reference numeral 1 in the figure is a detector for smoke, gas, heat, radiation, etc. When the purpose is to prevent fire, it consists of a smoke detector, thermoelectric stack, thermistor, photoelectric conversion element, etc.
When the purpose is to prevent gas leakage, a gas detector is used, and when the purpose is to prevent radiation leakage in a nuclear reactor, a radiation detector is used. is configured to output. 3
is a memory circuit, which includes a plurality of memory elements 7 ₁ , 7 ₂ , 7 ₃ . . .
..., and sequentially stores the detection signals outputted from the detector 1 for each oscillation pulse into memory elements 7 ₁ , 7 ₂ , 7 ₃ ...
...On the other hand, when a new detection signal is input, the oldest one of the stored detection signals is erased and a new signal is stored in its place, which is controlled by a clock pulse. 8 is an arithmetic circuit, each memory element 7 ₁ , 7 ₂ , 7 ₃ of the memory circuit 7
It calls out the detection signals stored in ... and calculates their average value. 5 is a comparator circuit that compares the signal output from the detector 1 based on the clock pulse, that is, the current detection signal, and the average value from the arithmetic circuit 8, and when the difference between the two exceeds a certain value. The system operates the response device.

Next, the operation of the apparatus configured as described above will be explained.

When a clock pulse is output from the clock pulse oscillator 2, a gate (not shown) of the memory circuit 3 is closed, and the clock pulse oscillator 2 outputs a clock pulse.
' are stored in the memory elements 7 ₁ , 7 ₂ , 7 ₃ .

Under these conditions, the detection sensitivity of detector 1 decreases due to long-term use, and becomes DX・ρ (DX is the initial detection signal level and ρ is the attenuation rate, where 1<ρ<0). In this case, if the number of storage elements is 10, the value output from the arithmetic circuit 8 will be 10・DX・ρ/10=DX・ρ, which is the same as the current detected value DX・ρ, so it can be compared. No signal is output from the circuit 5, and no malfunction will occur.

Next, the physical quantity to be measured is 1 at (t ₀ ),
2 at (t ₁ ), 3 at (t ₂ )... or less (t ₉ )
If it changes slowly at △1 per second, such as 10 at and 11 at (t10), from (t ₀ ) to (t ₉ )
The detection signal of the detector _{1 at} each clock pulse _up to
..., and by the clock pulse (t11), all these stored signals are sent to the arithmetic circuit 8.
and calculate the average, (1+2+3+4+5+6+7+8+9+
10)/10=5.5 is obtained, and this signal is sent to the comparator circuit 5 using the clock pulse signal at (t10) above.
and is compared with the detection signal (11) of the detector 1 in the above (t10).

As a result, the comparison circuit 5 outputs a signal of (11-5.5=5.5), and even if the physical quantity changes gradually, the comparison value becomes large and the response device 6
It will be at a sufficient level to make it work. If the level of this signal is greater than the value that should activate the response device 6, it is output to the response device 6 to activate it.

On the other hand, if a physical quantity suddenly changes due to an accident, a detection signal can be obtained even with a time delay of up to 1 second, and this signal is compared with the average value up to now by the comparison circuit 5, so that a large The response device 6 can be actuated by obtaining the level signal.

On the other hand, if a simple comparison is made with the previous detection signal stored in the memory circuit, the level for point-by-point comparison will be updated, so the slow change in physical quantity of △1 per second as described above will not be detected. If this is to be detected, the detection update period must be longer than 5 seconds. However, if the detection period is set to be long in this way, if the physical quantity suddenly changes, the response device will not be able to operate until a maximum of 5 seconds has passed, resulting in a delay in response.

When the comparison is completed in this way, the memory circuit 3
The oldest signal stored in the storage element ', in this example the value 1 at t ₀ , is erased and the detected value 10 at t ₁₀ is stored in its place.

Thereafter, such a process is repeated while monitoring slow changes or abnormal changes in physical quantities.

In this embodiment, the difference from the average value is calculated, but it is clear that the same effect can be obtained even if the quotient is calculated using a comparison circuit.

(Effects) As explained above, according to the present invention, the average value of a plurality of detection signals sampled over time is obtained and this average value is compared with the current detection signal. Even if the fluctuation is small, by comparing the integrated fluctuations, it is possible to obtain a comparison result with a large level, and while avoiding malfunctions due to changes in detector sensitivity over time, it is possible to It is possible to reliably operate the response device even when there is a slight variation in the physical quantity itself, and to quickly operate the response device in response to an abnormally large variation, thereby improving reliability.

[Brief explanation of the drawing]

The figure is a block diagram of an apparatus showing one embodiment of the present invention. 1...Detector, 2...Clock pulse generator,
3'...Memory circuit, 5...Comparison circuit, 6...Response device, ₇₁ , ₇₂ , ₇₃ ...Storage element.

Claims (1)

[Scope of Claims] 1. A detector that outputs a detection signal for each oscillation pulse of a clock pulse oscillator, and a plurality of detectors that are controlled by the oscillation pulses of the clock pulse oscillator and store the detection signals while sequentially updating them one by one over time. a storage circuit having a storage area, an arithmetic circuit for calculating an average value of data in the plurality of storage areas, and a comparison value between the two is set by comparing the average value and the detection signal from the detector using the clock pulse. A detection response device for smoke, gas, heat, radiation, etc., comprising a comparison circuit that outputs a signal when a value exceeds a value, and a response device activated by the signal from the comparison circuit. 2. The detection and response device for smoke, gas, heat, radiation, etc. according to claim 1, wherein the comparison circuit calculates the difference between the detection signal of the detector and the average value from the arithmetic circuit. . 3. The comparison circuit calculates the ratio by dividing the detection signal of the detector and the average value from the arithmetic circuit. Detection response device.