JPS5821020Y2 - Fire detector with test function - Google Patents

Description

[Detailed description of the invention] The present invention relates to a fire detector with a test function, which allows the fire detector to be operated by operating the test contacts from outside the fire detector, and which is tamper-proof. This prevents the test contacts from being manipulated by anyone.

Generally, the operation of a fire detector is tested by creating an environment similar to a fire for the fire detector.

Therefore, for example, in the case of a smoke detector, the operation is confirmed by blowing smoke on it, or in the case of a thermal detector, by applying heat.

Separately, when checking the sensitivity of a smoke detector, remove the smoke detector, gradually increase the smoke concentration in a test chamber containing a smoke densitometer, and measure the smoke concentration when activated. things are being done.

In ionization smoke detectors, a voltage is applied to the ion chamber and the applied voltage is read when the sensor is activated to determine whether the sensor is good or not.

By the way, in the above-mentioned operation test, smoke is actually used, so in hospitals or hotels, smoke may give off a smell, or using incense sticks may bring bad luck.
There are some places where testing is not possible.

Moreover, such a test requires about 60 seconds for each piece, so there is a drawback that the test takes a long time.

It is known that Freon gas, which has no odor, can be used to eliminate the above-mentioned odor-related disadvantages, but Freon gas is expensive and requires a high-pressure cylinder, making it heavy and difficult to transport. Ta.

Furthermore, as mentioned above, when smoke is actually used, it has the disadvantage that it cannot be carried out in places where there is a risk of gas explosion or the like.

The present invention eliminates the above-mentioned drawbacks, and enables an operation test to test whether a sensor works without actually using smoke or the like, and also requires no power supply when testing the operation of a sensor. This provides a fire detector with a test function that does not require testing.

An embodiment of the present invention will be described in detail below with reference to FIGS. 1 and 2.

1 and 2 show an ionization type smoke detector to which the present invention is applied.

In the figure, 1 indicates a case of the sensor, and the case has holes 4a and 4b into which a permanent magnet 3 fixed to the tip of a rod 2 can be inserted.
, 4b, a non-operation test relay contact A1 and an operation test relay contact B are arranged, respectively.

Reference numeral 5 indicates a smoke detection section, and 6 indicates an electric circuit section such as a comparison circuit, an amplifier circuit, and a switching circuit.

As shown in FIG. 2, the smoke detection unit 5 consists of an internal chamber 7 having a structure that prevents outside air from entering, and an external chamber 8 having a structure that allows outside air to enter relatively easily, and these chambers 7.8 are connected in series. A predetermined voltage is applied from signal and power supply lines 9a and 9b drawn out from a well-known receiver (not shown).

The FET is a field effect transistor, and a bridge is formed with resistor R4, series-connected resistors R2 + R3 + R4 + the internal chamber 7 and external chamber 8 as one side, and the FET is configured to monitor the equilibrium state of this bridge. has been done.

The external chamber 8 and the internal chamber 7 each have a radiation source 1o, ii, the air inside the chambers 8, 7 is ionized, and an ion current flows due to the above-mentioned applied voltage.

This ionic current generates a voltage across the external chamber 8, which in the balanced state of the bridge is connected to the resistor R2 connected in series with the resistor R1 in the FET.
The voltage divided by R3 and R4 is lower than the voltage between the applied source and gate, and the FET does not operate.

When smoke enters the external chamber 8, the ion current decreases and the voltage across the external chamber 8 increases, and when this becomes higher than the voltage between the source and gate of the FET, the bridge The equilibrium is destroyed and the above FET
works.

This operation causes the transistor Q that constitutes the above amplifier circuit to
7. When Q2 is turned on, the thyristor SCR constituting the switching circuit is turned on and the lines 9a and 9b are short-circuited, and the short-circuit activates the alarm relay of the receiver and issues an alarm. .

The above FET connects the voltage across the external chamber 8 with the source
This constitutes the above-mentioned comparison circuit that compares the voltage between the two ports.

As outside air enters the external chamber 8, dust also enters, but if this dust increases, the above-mentioned ion current decreases, and the voltage across the external chamber 8 increases, potentially causing false alarms. be.

When the lead contact A is closed, the resistor R4 is short-circuited and the voltage at the source of the FET becomes low, and the voltage between the source and the gate becomes low.
The resistance value of the resistor R4 is selected so that T does not operate.

Therefore, if the FET operates with the lead contact A closed, it can be seen that a large amount of dust has entered the external chamber 8.

When the lead contact B is closed, the resistors R3 and R4 are short-circuited, and the source-gate voltage of the FET becomes even lower.The resistance value of the resistor R3 is selected so that the FET operates at this voltage even under normal conditions. There is.

Therefore, if no alarm is generated even after closing the lead contact B, it can be determined that the sensor is malfunctioning.

In other words, an operation test to check whether the fire detector operates or not can be performed by inserting the permanent magnet 3 into the hole 4b and closing the reed contact B.

In addition to the function inspection, when performing a sensitivity test for comprehensive inspection of the fire detector, that is, a test to determine whether the fire detector operates with normal sensitivity, first insert the permanent magnet 3 into the hole 4a.
Insert the permanent magnet 3 into the hole 4b and close the lead contact A for the inoperability test to confirm that the fire detector does not operate. Next, insert the permanent magnet 3 into the hole 4b and close the lead contact B for the operation test. This is done by confirming that the fire detector is activated, indicating that the sensitivity is normal.

Further, when the sensitivity is not normal, it is possible to easily detect that more dust has entered the external chamber 8 and that the sensor is malfunctioning.

That is, it was found that when the permanent magnet 3 was inserted into the hole 4a and operated, more dust entered the hole 4a.
If the permanent magnet 3 does not operate even after inserting it into b, it is known that the sensor is malfunctioning.

In this way, sensitivity test force S is better than a conventional sensitivity test in which the smoke detector is removed and the smoke density is gradually increased in a tester containing a smoke density meter, thereby measuring the smoke density when activated. can also be easily done.

FIG. 3 shows another embodiment, in which the present invention is applied to a photoelectric smoke detector.

In FIG. 3, 12a and 12b are signal and power supply lines led out from a well-known receiver (not shown), and transistors Q8 and 12b are connected to the lines. Transistor Q5 via a constant voltage circuit consisting of Q4, Zener diode ZD, etc.
．． A power supply current is supplied to an amplifier circuit made up of Q6, a detection section made up of an OP amplifier 13, etc., and a pulse oscillator 14.

Reference numeral 15 denotes a light source made of a light emitting diode or the like, which is driven by the pulse oscillator 14 described above.

Light from this light source 15 is irradiated onto a light receiving element 16, and the output of the light receiving element is input to the OP amplifier 13.

If smoke enters between the light source 15 and the light receiving element 16 and the output of the light receiving element 16 falls below a predetermined level, the OP amplifier 1
3 produces an output.

This is the transistor Tsuru. It is amplified by Q6 and turns on the thyristor SCR.

Due to this turning on, the above lines 12a and 12b are short-circuited,
The warning alarm 1/- provided in the receiver is activated, and an alarm is issued by this activation.

The resistors R, , R2, R3, and R4 are for setting the threshold voltage of the OP amplifier 13, and the divided voltage between the resistor R1 and the resistors R2, R3, and R4 connected in series is the above-mentioned O.
It is applied to the P amplifier 13.

A and B are the above-mentioned reed contacts, and by closing the reed contact A with the above-mentioned permanent magnet 3 or the like, the resistor is short-circuited, and the above-mentioned applied voltage is slightly lowered.

If the OP amplifier 13 produces an output by slightly lowering this applied voltage, the sensitivity of this sensor will be too sensitive and there is a risk of malfunction.

Furthermore, by closing the lead contact B with the permanent magnet 3 or the like, the resistors R3 and R4 are short-circuited, the above applied voltage is significantly reduced, and an output is generated in the OP amplifier 13.

This allows the operation test to be performed. If the OP amplifier 13 does not produce an output even when the applied voltage is significantly lowered, it can be determined that the sensor is insensitive or that there is a malfunction in the sensor.

Therefore, when performing a sensitivity test next time, if there is no activation when reed contact A is closed, and there is activation when reed contact B is closed, the sensor is normal, and the sensor is activated when reed contact A is closed. If there is an operation even when reed contact B is closed, the sensitivity is too sensitive, and if there is no operation when reed contact A is closed and there is no operation even when reed contact B is closed, the sensitivity is too sensitive or the sensitivity is too sensitive. It turns out that there is a malfunction in the equipment.

The above embodiments show examples of ionization type smoke detectors and photoelectric type smoke detectors, but in a thermal type sensor using heat-sensitive ferrite, the sensor is activated by bringing a permanent magnet close to the reed switch of the contact part. It can also be implemented by letting

As mentioned above, the present invention is equipped with an operation test relay contact that is activated by external magnetic force and activates the fire detector, making it possible to test the operation of the detector without actually using smoke or the like. In addition, it does not require a power source for testing the operation of the sensor, and furthermore, there is no possibility of tampering with the sensor, unlike the case of testing by pushing a button, which is a very useful effect in practical terms.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing one embodiment of the present invention, and Fig. 2 is a block diagram showing an embodiment of the present invention.
FIG. 3 is a circuit diagram showing another embodiment. 3...Permanent magnet, A...Reed contact for non-operation test, B...Reed contact for operation test.

Claims (1)

[Scope of utility model registration request] A fire detector having a test function, characterized in that an operation test lead contact, which is operated by an external magnetic force and causes the fire detector to be activated, is connected to an electric circuit provided within the fire detector.