JP3121134B2 - Smoke detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-sensitivity smoke type fire detector for calibrating sensitivity characteristics by taking a plurality of sample gases into a smoke chamber.

[0002]

2. Description of the Related Art When calibrating sensitivity characteristics of a smoke detector by taking a plurality of sample gases into a smoke chamber, conventionally, oxygen gas,
Two kinds of pure gases having significantly different molecular weights, such as Freon 12 (CCl ₂ F ₂ ) gas, are alternately passed through a smoke chamber, and light generated by a light-emitting lamp is scattered by molecules of the sample gas. The sensitivity characteristic of the smoke detector is calibrated using the fact that the light receiving element captures the light.

[0003] That is, pure gas is stable in concentration, and when attention is paid to a certain pure gas, the pure gas is taken into a smoke chamber, and when the pure gas is detected as smoke, a value of a certain smoke concentration is output. And the output smoke density value is very small. In other words, since a certain pure gas and smoke density correspond, and the smoke density is very low,
By utilizing this, it is possible to calibrate the sensitivity characteristic of a highly sensitive smoke detector.

FIG. 5 is a circuit diagram showing a main part of a conventional smoke detector.

In this conventional example, light is emitted from a xenon lamp (not shown), and after the light generated by the xenon lamp is scattered, the scattered light is received by a light receiving element 81, and the peak value of the output signal of the light receiving element 81 is peaked. The data held by the hold circuit 84 and obtained by subtracting a predetermined value from the peak value by the subtraction circuit 85 is sent to the receiver via the signal output circuit 87. The variable resistor 83 for adjusting the gain adjusts the gain of the amplifier 82,
The middle offset variable resistor 86 is a resistor for adjusting the predetermined value to be subtracted from the peak value.

[0006]

FIG. 6 is a diagram showing the relationship between the smoke density and the value of the current output from the signal output circuit 87 in the above conventional example.

FIG. 6 shows the value of the output current of the signal output circuit 87 with respect to the concentration when pure oxygen gas and Freon 12 gas are alternately taken into the smoke chamber at 1 atmosphere and normal temperature. In FIG. 6, a characteristic C1 is a characteristic when the sensitivity of the smoke detector is not adjusted.
3 is a characteristic when the sensitivity adjustment is completed. That is,
The variable resistor 83 for gain adjustment and the offset amount adjustment so that the output current of the signal output circuit 87 when using oxygen gas becomes I1 and the output current of the signal output circuit 87 when using Freon 12 becomes I2. The characteristic C3 is determined by adjusting the output current of the signal output circuit 87 when oxygen gas is used.
And the output current of the signal output circuit 87 when the Freon 12 is used becomes I2.

To adjust the sensitivity of the smoke detector, the characteristic C1
Adjustment of the tilt and translation. Actually, the output of the smoke detector is adjusted while looking at the ammeter or the like. First, by taking in Freon 12 gas and operating the variable resistor 83 for gain adjustment, the output of the signal output circuit 87 matches I2. The characteristic C1 is adjusted so as to obtain the characteristic C21. Next, by taking in oxygen gas and operating the variable resistor 86 for adjusting the offset amount, the signal output circuit 87 is obtained.
The characteristic C21 is translated so that the output of the characteristic C2 coincides with I1 to obtain the characteristic C22. Then, the Freon 12 gas is taken in again, and by operating the variable resistor 83 for gain adjustment, the slope of the characteristic C22 is adjusted so that the output coincides with I2 to obtain the characteristic C23. Hereinafter, this operation is repeated until the characteristic matches C3.

As described above, when the characteristic is changed from C1 to C3, if the offset amount adjusting variable resistor 86 is adjusted (by parallel movement) so that one output data coincides with I1, the other data becomes I2. Since they do not match,
Characteristic C3 cannot be determined, and then to adjust this slope so that the other output data matches I2,
When the variable resistor 83 for gain adjustment is adjusted, one of the output data cannot be kept coincident with I1, and thus the characteristic C3 cannot be accurately obtained. Therefore, if the adjustment operation for obtaining the characteristics twice (the operation of using the oxygen gas and the Freon 12 gas once each) is executed, the sensitivity adjustment does not end.

[0010] Of course, in the course of repeating these operations, gradually, but closer to the characteristics C3, For that purpose, a number of characteristic times, it is necessary to obtain, each time, 100 a gas
% Replacement is required, and the gas replacement operation is not easy and complicated. For this reason, in the above-mentioned conventional device, there is a problem that the sensitivity adjustment work of the smoke detector is complicated and the sensitivity adjustment work takes a long time.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a smoke detector which can easily adjust the sensitivity of a smoke detector and can complete the sensitivity adjustment in a short time.

[0012]

According to the present invention, a light receiving element receives light from a light emitting lamp and outputs an A / D signal from the light receiving element.
The conversion circuit converts the signal into a digital signal, and the calculation means performs calculation based on the output data of the A / D conversion circuit. The signal output circuit sends a signal based on the output of the calculation means to the receiver, and receives the smoke density display device. The output data of the A / D conversion circuit when the smoke chamber is filled with the first gas is stored in the memory as the first calibration data, and the smoke chamber is filled with the second gas. The output data of the A / D conversion circuit at that time is stored in the memory as the second calibration data, and the calculating means calculates the first calibration data, the second calibration data, and the output data of the A / D conversion circuit. Thus, the output data required to display the appropriate smoke density corresponding to the output data of the A / D conversion circuit on the smoke density display device is calculated.

[0013]

According to the present invention, the memory stores the output data of the A / D conversion circuit as the first calibration data when the smoke chamber is filled with the first gas, and fills the smoke chamber with the second gas. The output data of the A / D conversion circuit during the
Is stored in the memory as the calibration data of
Based on the calibration data, the second calibration data, and the output data of the A / D conversion circuit, the output necessary for displaying the appropriate smoke density corresponding to the output data of the A / D conversion circuit on the smoke density display device. Since the data is calculated, when the sensitivity of the smoke sensing device is adjusted, the adjustment operation is completed only by using the first gas and the second gas once each. It is easy and the sensitivity adjustment operation can be completed in a short time.

[0014]

FIG. 1 is a block diagram showing an embodiment of the present invention.

In the smoke detector 1 of this embodiment, the smoke room 3
The xenon lamp 10 and the light receiving element 20 are provided in the inside of the light shielding plate 34.
Are separated by And a xenon lamp 10
Emits light, and the light is scattered by the smoke in the smoke chamber 30 and reaches the light receiving element 20.

The xenon lamp 10 is supplied with a high voltage necessary for light emission from a high voltage generation circuit 12 and a trigger circuit 11
The light emission timing is controlled by a trigger signal supplied from. The trigger circuit 11 generates a trigger signal based on a control signal supplied from the control circuit 50.

The smoke chamber 30 is connected to a sampling pipe 31 for guiding the atmosphere in which the smoke detector 1 is provided to the smoke chamber 30, and a pipe 32 for guiding the air in the smoke chamber 30 to the outside of the smoke detector 1. A suction fan 33 is provided in the pipe 32.

The amplifier 40 amplifies the output signal of the light receiving element 20, the gain of which is controlled by a gain switching circuit 41. The peak hold circuit 42 is a circuit for holding the peak of the output signal of the amplifier 40. , A / D
The conversion circuit 43 is a circuit that converts an analog signal output from the peak hold circuit 42 into a digital signal.

The control circuit 50 is composed of a microcomputer or the like, controls the smoke detector 1 as a whole,
The current smoke density in the smoke chamber 30 is determined based on the digital signal from the / D conversion circuit 43.

The ROM 60 stores the program of the flowchart shown in FIG. EEPROM 61
Stores, as the first calibration data, the output data of the A / D conversion circuit 43 when pure oxygen gas is sucked into the smoke chamber 30 at 1 atm and room temperature, for example.
A / D when pure gas of No. 2 is sucked into the smoke chamber 30
The ROM stores output data of the conversion circuit 43 as second calibration data. The RAM 64 is a working memory.

The D / A conversion circuit 71 includes a signal output circuit 7
2. To send a signal to the receiver 2 via the connector C,
This is a circuit that converts a digital signal output by the control circuit 50 into an analog signal. The receiver 2 includes a smoke density display device 2d (shown in FIG. 4) for displaying smoke density.

The calibration confirmation light circuit 74 is a circuit that indicates that the sensitivity of the smoke detector 1 is being adjusted when the sensitivity is being adjusted.

The switches SW1 and SW2 are locking switches operated according to the type of gas used when calibrating the sensitivity of the smoke detector 1, and the switch SW3 is used when calibrating the sensitivity of the smoke detector 1. This is a non-lock type switch that is turned on for 5 seconds or more.

The EEPROM 61 for storing the detected value of the reference gas for memory calibration stores the output data of the A / D conversion circuit when the smoke chamber is filled with the first gas as first calibration data. 5 is an example of a memory that stores output data of an A / D conversion circuit when a smoke chamber is filled with a second gas as second calibration data. Also, EE
The PROM 61 is an electrically rewritable nonvolatile memory.

The control circuit 50 and the ROM 60 are examples of arithmetic means for performing a predetermined operation based on the output data of the A / D conversion circuit. The arithmetic means includes first calibration data and second calibration data. And means for calculating output data necessary for displaying an appropriate smoke density corresponding to the output data of the A / D conversion circuit on the smoke density display device based on the output data of the A / D conversion circuit.

[0026] More specifically, the calculating means, the first calibration data and x _1, the second calibration data and x _2, A /
The current output data D converter and x, the output data required for displaying a smoke density corresponding to the first gas to the smoke density display device as y _1, the smoke density corresponding to the second gas Output data required for display on the smoke density display device is y ₂
Where y is the output data necessary to display the appropriate smoke density corresponding to the output data of the A / D conversion circuit on the smoke density display device, y = {(y ₂ −y ₁ ) / (x ₂ -x ₁ )} · x + (y ₁ · x _{2
-y 2 · x 1) / (} x 2 -x 1) by calculating the output data
It calculates y.

Next, the operation of the above embodiment will be described.

FIG. 2 is a flowchart showing the operation of the above embodiment. In this flowchart, S11 to S11
S23 is a preparation operation for adjusting the sensitivity of the smoke detector 1,
S1 to S4 are smoke detection operations including sensitivity adjustment.

First, the preparatory operation for sensitivity adjustment will be described.

Before executing the sensitivity adjustment of the smoke detector 1, 1
At atmospheric pressure and normal temperature, the switch SW1 is charged while filling the smoke chamber 30 with pure oxygen through the sampling pipe 31.
Is turned on, the switch SW2 is turned off, and the switch SW3 for the sensitivity adjustment command is turned on for 5 seconds or more. In this way, when the sensitivity adjustment command switch SW3 is turned on for 5 seconds or more (S11), the confirmation light of the calibration confirmation light circuit 74 is lit for one second to inform that the sensitivity adjustment operation will be performed from now on (S11). S12). At this time, since the switch SW1 is on and the switch SW2 is off (S13,
4) In a state where the smoke chamber 30 is filled with pure oxygen, the output signal of the light receiving element 20 is amplified, the peak value of the amplified signal is held in the peak hold circuit 42, and this peak value is A / D converted. The converted output data is converted into digital data by the circuit 43, and the converted output data is used as the first calibration data x _1.
Is stored in the EEPROM 61 (S15), and the smoke detection operation (S1 to S4) described later is executed.

Then, the pure oxygen gas is discharged from the pipe 32 and the smoke chamber 30 is filled with pure Freon 12 (F12) through the sampling pipe 31 at 1 atm and normal temperature, and the switch SW1 is turned off. S
W2 is turned on, and a switch SW3 for a sensitivity adjustment command is set.
For more than 5 seconds. In this way, when the sensitivity adjustment command switch SW3 is turned on for 5 seconds or more (S11),
The confirmation lamp of the calibration confirmation lamp circuit 74 is turned on for one second to notify that the sensitivity adjustment operation is to be performed (S12). At this time, since the switch SW1 is off and the switch SW2 is on (S13, S21), the output signal of the light receiving element 20 is amplified by the amplifier circuit 40 with the pure Freon 12 filling the smoke chamber 30, The peak value of the amplified signal is held in a peak hold circuit 42, and this peak value is converted into digital data by an A / D conversion circuit 43. The converted output data is used as EEPROM 61 as _second calibration data x2. (S22), and performs the smoke detection operation (S1 to S4) described later. The switch S
If both W1 and SW2 are on, the EEPROM 61
The data other than the calibration data is cleared out of the data stored in (2) (S23).

Next, the smoke density detecting operation including the sensitivity adjustment, that is, the smoke detecting operation will be described.

When the preparation operation for sensitivity adjustment is completed as described above, the first calibration data x ₁ ,
Second calibration data x ₂ are read (S1), captures the (current output data of the A / D conversion circuit 43) x current detection data (S2). Then, the first calibration data x ₁ , the second
Calibration data x ₂ in the current detection data x, the output data y ₁ corresponding to the data x _1, on the basis of the output data y ₂ corresponding to the data x _2, smoke a proper smoke density corresponding to the current output data x The output data y to the D / A conversion circuit 71 necessary for displaying on the density display device 2d is transmitted to the control device 50 and the ROM 6
0 is used for calculation, that is, sensitivity adjustment (S3).

The output data y ₁ is necessary for displaying the smoke density (about 0.005% / m) corresponding to the oxygen gas (first gas) on the smoke density display 2 d of the receiver 2. Na D
The output data to the / A conversion circuit 71 is calculated in advance and stored in the ROM 60. Output data y ₂ is the smoke density (about 0 corresponding to freon 12 gas (second gas).
035% / m) is output data to the D / A conversion circuit 71 necessary for displaying the smoke density display device 2d, and is calculated in advance and stored in the ROM 60. That is, since the concentration of the oxygen gas is about 0.005% / m, when the oxygen gas is injected into the smoke chamber 30, as shown in FIG. Is turned on, and the concentration of Freon 12 gas is about 0.035% / m
Since it is, when injected Freon gas Kemurishitsu 30, as shown in FIG. 4 (2), "OK" in the smoke density display device 2d, "0.01", "0.02", " 0.0
"3" is lit.

That is, output data to the D / A conversion circuit 71 necessary for displaying the appropriate smoke density corresponding to the current output data x on the smoke density display device 2d is transmitted to the control device 50.
And the ROM 60, the characteristic to be obtained is generally expressed by the equation y = ax + b, as shown in FIG. 3, and the general equation "y = ax + b""Y = {(y ₂ −y ₁ ) / (x
_{2 -x 1)} · x +} (y 1 · x 2 -y 2 · x 1) / (x 2 -x 1) "or less that will be described.

From FIG. 3, y ₁ = ax ₁ + b and y ₂ = ax ₂ + b. Solving the simultaneous equations based on these two equations gives a = {(y ₂ −y ₁ ) / ( x ₂ -x ₁ )}, and b = (y ₁ x ₂ -y ₂ x ₁ ) / (x ₂ -x ₁ ). Therefore, when a and b are substituted into the general formula, y = ax + b = {(y ₂ −y ₁ ) / (x ₂ −x ₁ )} × x (y ₁ × ₂ −y ₂ × ₁ ) / (x _2-
x ₁ ). The output data y obtained in this manner is represented by D /
When supplied to the A / A conversion circuit 71, the D / A conversion circuit 71 converts the output data y into an analog signal, and the signal output circuit 72 sends the signal to the receiver 2 so that the A / D conversion circuit 43 outputs Corresponding appropriate smoke density is smoke density display 2d
Will be displayed. For example, if the current smoke density is 0.06% /
m, “OK”, as shown in FIG.
"0.01" to "0.06" are lit.

In the above embodiment, pure gas is
Although the oxygen gas and the chlorofluorocarbon 12 gas are used, pure gases other than these may be used, or three or more kinds of pure gases may be used. Further, in the above-described embodiment, the case where the xenon lamp is used has been described. However, a light-emitting lamp other than the xenon lamp may be used.

In the above embodiment, an analog signal is transmitted to the receiver 2. However, a digital signal such as a pulse code may be transmitted. In the above embodiment, the EEPRO storing the first and second calibration data
Although the memory such as M61 and the calculation means are provided on the smoke detector side, one or both of them may be provided on the receiver 2 side or the repeater side (not shown).

Further, in the above embodiment, the smoke density display device 2d is provided on the receiver 2 side, but may be provided on the smoke detector 1.

[0040]

According to the present invention, the output data of the A / D conversion circuit when the smoke chamber is full of the first gas is stored in the memory as the first calibration data, and the second data is stored in the smoke chamber. The output data of the A / D conversion circuit when the gas is full is stored in the memory as the second calibration data, and the arithmetic means stores the first calibration data, the second calibration data, and the A / D
Based on the output data of the conversion circuit, the output data required to display the appropriate smoke density corresponding to the output data of the A / D conversion circuit on the smoke density display device is calculated, so that the sensitivity of the smoke detection device is adjusted. In this case, the adjustment operation is completed only by using the first gas and the second gas once each, the sensitivity adjustment operation of the smoke sensing device is easy, and the sensitivity adjustment operation is completed in a short time. It has the effect of being able to do so.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of the embodiment.

FIG. 3 is a diagram showing a relationship between output data of an A / D conversion circuit 43 and output data to a D / A conversion circuit 71 in the embodiment.

FIG. 4 is a diagram showing a smoke density display device 2d provided in a receiver connected to the embodiment.

FIG. 5 is a circuit diagram showing a main part of a conventional smoke detector.

FIG. 6 shows the smoke density and the signal output circuit 8 in the conventional example.
FIG. 7 is a diagram illustrating a relationship with a value of a current output by a reference numeral 7.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Smoke detector, 2 ... Receiver, 2d ... Smoke density display device, 10 ... Xenon lamp, 11 ... Trigger circuit, 20 ... Light receiving element, 30 ... Smoke room, 40 ... Amplifier circuit, 41 ... Gain switching circuit, 50 ... Control circuit, 60 ... ROM, 61 ... EEPROM for storing the detected value of calibration reference gas, 74 ... Calibration confirmation light circuit

Continuation of front page (56) References JP-A-60-246497 (JP, A) JP-A-53-144388 (JP, A) JP-A-4-599 (JP, A) (58) Fields investigated (Int) .Cl ^7, DB name) G08B 17/00 -. 17/12 G01N 21/53

Claims (3)

(57) [Claims] 1. A smoke chamber including a light-emitting lamp and a light-receiving element for receiving light from the light-emitting lamp; an A / D conversion circuit for converting an output signal of the light-receiving element into a digital signal;
Calculation means for performing a predetermined calculation based on the output data of the A / D conversion circuit; a signal output circuit for sending an output signal of the calculation means to a smoke density display device for displaying smoke density; Output data of the A / D conversion circuit when the first gas is full is stored as first calibration data, and the A / D conversion when the smoke chamber is full with the second gas is stored. A memory for storing output data of the circuit as second calibration data; and wherein the arithmetic means stores the first calibration data, the second calibration data, and the output data of the A / D conversion circuit. A smoke detection device for calculating output data necessary for displaying an appropriate smoke density corresponding to output data of the A / D conversion circuit on the smoke density display device based on the output data. 2. The method of claim 1, the first calibration data and x _1, the second calibration data and x _2, the output data of the A / D converter circuit and x,
The output data required for displaying a smoke density corresponding to said first gas to said smoke density display device as y _1, the second
Show the smoke density corresponding to the gas output data required for display on the smoke density display device and y _2, a proper smoke density corresponding to the output data of the A / D converter on the smoke density display device When the output data to the D / A conversion circuit necessary for performing the above operation is y, the arithmetic means calculates y = {(y ₂ −y ₁ ) / (x ₂ −x ₁ )} · x + (y by calculating the _{1 · x 2 -y 2 · x} 1) / (x 2 -x 1), the smoke sensing apparatus characterized in that for calculating the output data y to the D / a converter . 3. The method of claim 2, smoke detection apparatus characterized by storing and the output data y ₁ and the output data y ₂ to a predetermined storage means.