JP2583396Y2 - Carbon monoxide gas 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 carbon monoxide gas detector which is synchronized with the ignition of a combustor and which prevents malfunction at the initial stage of ignition.

[0002]

2. Description of the Related Art Recent combustors are provided with a carbon monoxide gas detector (hereinafter abbreviated as "gas detector") in order to prevent incomplete combustion. The carbon monoxide gas sensor (hereinafter abbreviated as CO sensor) used for this has a heater and is used in a state where it is kept at a high temperature. Further, this CO sensor is used in a state where it is always installed in the flow path of the combustion exhaust gas.

[0003] There are two types of heating power sources for operation, one that is always energized, and one that receives a signal from the combustor and turns on the power in synchronization with ignition.

In the former case, as shown by the broken line in FIG. 5, when the combustor is ignited, a large amount of carbon monoxide gas (hereinafter, abbreviated as CO gas) is released, so that the concentration is high, and this is detected by the CO sensor. Output abnormally high as shown by the solid line.
For this reason, a malfunction may occur. In the latter case, as indicated by a broken line in FIG. 6, a combustor ignition at high concentration C
With the generation of O gas, the temperature of the combustion exhaust gas increases in 1 to 3 minutes.
Since the temperature rises from room temperature to 150 to 200 ° C. , the zero balance of the CO sensor is lost, resulting in an abnormal output state as shown by a solid line, which may cause a malfunction.

[0005]

As described above, in the conventional gas detector, the CO sensor is always installed in the flow path of the exhaust gas.
There is a disadvantage that a high concentration of CO gas at the time of ignition is immediately detected and a malfunction occurs. In addition, when energizing in synchronization with the combustion of the combustor, with the generation of high-concentration CO gas,
Zero balance of CO sensor due to temperature rise of flue gas
Is broken, and there is a problem that the output may exceed the set value and malfunction. In order to avoid these inconveniences, there is a method in which the CO sensor is operated after the temperature of the combustion exhaust gas reaches a stable combustion temperature. However, there is an inconvenience that it takes time to operate the CO sensor.

[0006] The present invention has been made to solve the above-mentioned disadvantages, as well as synchronize the ignition of the combustor, the combustion
Immediately monitor CO gas before the temperature of exhaust gas stabilizes
It is an object of the present invention to provide a gas detector which is arranged and prevents malfunction.

[0007]

In order to achieve the above object, the present invention provides a carbon monoxide gas sensor for detecting carbon monoxide gas in combustion exhaust gas and outputting a concentration signal, and a delay means for the carbon monoxide gas sensor. Sensor driving means for supplying and driving a heating current through the sensor, and an alarm device for issuing an alarm when the concentration signal of the carbon monoxide gas sensor driven by the sensor driving means exceeds a set value, and is delayed from ignition. A carbon monoxide gas detector that drives a carbon monoxide gas sensor, wherein the delay unit is heated by combustion exhaust gas by ignition and outputs a temperature signal;
A switching section for closing the supply circuit of the heating current when the output from the ignition detection section exceeds a set value , wherein a temperature of the set value for closing the supply circuit is lower than a stable combustion temperature of the combustion exhaust gas . And the monoacid after ignition
This carbon monoxide gas
Temperature exceeding the temperature at which the sensor's zero balance is lost and malfunctions
It has a configuration that is.

[0008]

In the present invention, the start of energization to the CO sensor is controlled by the output of the ignition detection unit which is heated and output by the combustion exhaust gas, so that the energization operation is reliably started in synchronization with ignition. In addition, since the energization is started with a delay from the ignition, a malfunction at the initial stage of the ignition is reliably prevented.
The set temperature at which the energization of the CO sensor is started is lower than the stable combustion temperature at which the temperature of the flue gas is stabilized , and is on a rising temperature gradient , and the carbon monoxide gas sensor after ignition
0 balun of this carbon monoxide gas sensor
Since the temperature exceeds the temperature at which the gas collapses and malfunctions , the CO gas can be monitored immediately after ignition, and there is no risk of malfunction at this time. In addition, since no special synchronization means is required for synchronizing with the ignition, it can be easily attached to existing equipment, and power is supplied only during use, so that power can be saved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to an embodiment shown in FIGS.

Reference numeral 1 denotes a sensor output detecting means.
And the alarm 3 are connected, and the output of the CO sensor 2 is taken out by the sensor output detecting means 1 and output to the alarm 3 as a concentration signal. When the density signal exceeds the set value, the alarm 3 is activated.

The sensor driving means 4 is connected to a power supply 5 and supplies electric power to the sensor output detecting means 1, the alarm device 3 and the like, and also energizes the heater of the CO sensor 2 to keep it at a predetermined temperature. It is.

The sensor driving means 4 is provided with a delay means 6 shown in FIG. The means 6 includes a temperature sensor 61 such as a platinum resistor or a thermistor built in the CO sensor 2 or an ignition detector 62 installed near the CO sensor 2.
And a decision circuit 63 and a switching circuit 64
And a switching unit 65 . Then, the temperature sensor 61 in the combustion exhaust gas is heated, and a temperature signal corresponding to the temperature is transmitted.
Issue an issue. The output determination circuit 63 receives this output, and outputs an operation signal if the output is determined to be equal to or greater than the set value. With this operation signal, the switching circuit 64 becomes conductive, and CO
The heater of the sensor 2 is energized. Therefore, the detection of CO gas by the CO sensor 2 is delayed from ignition until the temperature sensor 61 outputs a predetermined output after ignition.

Next, taking the case where this gas detector is attached to the flow path of the flue gas of the water heater as an example, the flow chart of FIG. 3 and the temperature of the flue gas of FIG.
This will be described with reference to a diagram showing the relationship between the O gas concentration and the output of the CO sensor.

(Step P1) The combustor is ignited.

(Step P2) In about 1 to 2 minutes, the temperature of the flue gas rises to about 80 to 100 ° C., and accordingly, the output of the temperature sensor 61 increases.

(Step P3) If the operating temperature of the switching section 65 is temporarily set to 80 ° C., the output determination circuit section 63 outputs an operation signal at that time, the switching circuit 64 operates, and the CO sensor 2 The heater circuit is closed
The sensor 2 is energized and operates.

(Step P4) Then, the CO sensor 2 enters a monitoring state.

The process up to this point will be described with reference to FIG.
The solid line a shows the sensor output versus time, the dashed line b shows the CO gas concentration in the flue gas versus time, and the dashed line c shows the temperature of the flue gas versus time. When ignited at time Ta, the temperature of the flue gas rises rapidly, and then slowly rises,
It will be level (stable combustion temperature). The CO gas concentration in the flue gas protrudes at the same time as the ignition, then rapidly decreases,
It changes in a very slight state. Further, the temperature sensor 61 is heated immediately after ignition, and when the output increases and reaches the set value at time Tb, the CO sensor 2 is energized. The output of the CO sensor 2 instantaneously protrudes at the same time as the power is supplied, but drops rapidly.
Therefore, the level immediately returns to the 0 level without exceeding the set density . When the energization of the CO sensor 2 is started, the CO gas concentration is already in a very low state, and the temperature rise gradient of the combustion exhaust gas is not so steep as at the time of ignition.

(Step P5) The combustor is extinguished.

(Step P6) The temperature of the exhaust gas decreases.

(Step P7) The temperature of the exhaust gas channel decreases, the temperature of the temperature sensor also decreases, and the power supply to the CO sensor stops.

This is the end of the description of the embodiment.

Although the delay circuit of this embodiment is composed of a temperature sensor, an output determination circuit and a switching circuit, the invention is not limited to this. Any configuration may be used as long as the switch is turned on and off by being heated by the combustion exhaust gas.

[0024]

As described in detail above, in the present invention, the start of energization to the CO sensor is controlled by the output of the ignition detection unit which is heated and output by the combustion exhaust gas. And the energization operation is started
In addition, since the energization is started with a delay from the ignition, a malfunction at the initial stage of the ignition is reliably prevented. In addition, the set temperature at which the energization of the CO sensor is started is lower than the stable combustion temperature at which the temperature of the combustion exhaust gas is stabilized, and is on a rising temperature gradient.
After the fire, the carbon monoxide gas sensor
Temperature at which the zero balance of the carbon monoxide gas sensor is lost and malfunctions
Since the temperature exceeds the temperature , the CO gas can be monitored immediately after ignition, and there is no possibility of malfunction at this time. In addition, since no special synchronization means is required for synchronizing with the ignition, it can be easily attached to existing equipment, and power is supplied only during use, so that power can be saved.

[Brief description of the drawings]

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

FIG. 2 is a circuit diagram of a main part (delay means).

FIG. 3 is a flow chart for explaining the operation.

FIG. 4 is a diagram for explaining the operation before and after ignition.

FIG. 5 is a diagram illustrating the operation of a malfunction in a conventional example.

FIG. 6 is a diagram illustrating the operation of a malfunction in the conventional example.

[Explanation of symbols]

2 Carbon monoxide gas sensor (CO sensor) 3 Alarm 4 Sensor driving means 6 Delay means 62 Ignition detection unit 65 Switching unit

Claims (1)

(57) [Scope of request for utility model registration] 1. A carbon monoxide gas sensor for detecting a carbon monoxide gas in a combustion exhaust gas and outputting a concentration signal, a sensor driving means for supplying a heating current to the carbon monoxide gas sensor via a delay means and driving the sensor, and An alarm device for issuing an alarm when the concentration signal of the carbon monoxide gas sensor driven by the sensor driving means exceeds a set value; and a carbon monoxide gas detector for driving the carbon monoxide gas sensor with a delay from ignition. The delay means includes an ignition detection unit that is heated by combustion exhaust gas by ignition and outputs a temperature signal, and a switching unit that closes the heating current supply circuit when the output from the ignition detection unit exceeds a set value. consists of a part, the temperature set value closing the supply circuit, the less than stable combustion temperature of the combustion exhaust gas, and the carbon monoxide gas sensor after ignition
Zero balance of this carbon monoxide gas sensor by energizing drive
A carbon monoxide gas detector characterized by a temperature exceeding the temperature at which the gas collapses and malfunctions .