JP2592728Y2 - CO safety device for combustion equipment - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CO safety device for combustion equipment, such as an indoor type water heater, for ensuring safety against carbon monoxide gas.

[0002]

2. Description of the Related Art FIG. 5 shows a schematic structure of a water heater generally known as a combustion device, and FIG. 6 shows a usage mode in which the water heater 1 is installed in a room of a building. ing.

[0003] The operation of this type of water heater 1 is controlled by a control device 6. The control device 6 opens the faucet 9 and detects a flow of feed water by a flowing water sensor 21 provided in a water supply pipe 22. When the fan 2 rotates, air in the room is sent to the burner 4 through the filter 3 by the rotation of the fan 2,
20 is opened to burn the combustion gas supplied to the burner 4 to heat the heat exchanger 5, and to make the water passing through the heat exchanger 5 hot water,
The hot water is supplied to a desired place such as a kitchen through a hot water supply pipe 23 connected to the outlet side of the heat exchanger 5.

When installing this water heater 1 indoors,
The base of the chimney 10 is fitted to and fitted to the exhaust outlet tube 8 of the water heater 1, and the end of the chimney 10 is taken out of the building to take in the indoor air and discharge the exhaust gas burned out of the building. I have to.

[0005] When this type of water heater 1 is operated for combustion, if strong wind blows into the exhaust port of the chimney 10, incomplete combustion occurs and carbon monoxide gas (hereinafter referred to as CO gas) is generated. In the state where exhaust gas is completely exhausted outside through the chimney 10, the effect of CO gas in the room does not occur.However, if a gap is formed at the seam of the chimney 10 or the joint comes off, the part enters the room. There is a danger that the CO gas will flow back and cause CO gas poisoning.

For this reason, conventionally, as shown in FIG. 5, a CO sensor 11 is installed on the exhaust side of the water heater 1, and an alarm is issued when the concentration of CO gas in the exhaust gas reaches a dangerous concentration. And safety measures such as stopping the combustion operation are taken.

[0007]

However, when a person is exposed to the exhaust gas, even if the concentration of the CO gas is below the dangerous concentration, the blood hemoglobin CO concentration taken into the blood gradually increases. The blood hemoglobin CO concentration may reach a dangerous concentration and cause CO gas poisoning.
As shown in FIG. 4, the blood hemoglobin CO concentration taken into the blood varies depending on the CO concentration in the exhaust gas to reach the dangerous concentration of the blood hemoglobin CO concentration (for example, blood hemoglobin CO concentration 25%). Even if the CO concentration in the exhaust gas is low, for example, 1000 ppm, the dangerous concentration of the hemoglobin CO concentration in the blood will be reached over time, so the CO sensor 11 in FIG. Since the determination alone does not consider the blood hemoglobin CO concentration at all, there is a great problem in safety against CO gas poisoning.

Then, as shown in FIG. 8, the applicants, for example, detect the CO in the exhaust gas at each sampling time from the initial detection time t ₀ of the CO concentration in the exhaust gas, When a person is exposed to the atmosphere having the determined CO concentration, the blood hemoglobin CO concentration taken into the blood is integrated every time t, and, for example, D ₁ + D ₂ + D _3.
· · · D _n integration to time t _n at blood hemoglobin total concentration in blood hemoglobin CO previously given as
It is proposed that when the value of the area D indicated by the oblique line as the risk reference value of the concentration is reached, the value is determined as the risk reference concentration and safety measures such as stopping the combustion are taken.

However, as shown in FIG. 7, the CO sensor 11 detects that the CO gas concentration detected is a predetermined concentration (usually 10%).
00ppm), the sensor output will not be stable,
There is a problem that detection is not performed in the case of the following CO concentration. Therefore, CO gas is generated from the start of the combustion operation of the water heater or the like in the exhaust gas, blood hemoglobin is CO concentration as shown in FIG. 8 is taken into the blood blank time t ₀ to reach 1000ppm CO concentration could not be detected. Therefore, in the proposed example, when the blood hemoglobin CO concentration reaches the integrated concentration D at time t _n , the blood hemoglobin CO concentration is output as a dangerous concentration as a warning concentration. Since the blood hemoglobin CO concentration taken into the blood is not considered at all, the blood hemoglobin CO concentration actually taken into the blood is only the blood hemoglobin CO concentration taken into the blood during the blank time compared to the dangerous reference concentration. More
It will exceed the risk standard concentration. Therefore,
This method is still insufficient in terms of security, and there is room for improvement.

The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to consider the blood hemoglobin CO concentration taken into the blood during a blank time from the start of the combustion operation to the detection of the CO concentration. Provided is a CO safety device for a combustion device capable of judging a dangerous concentration closer to the actual blood hemoglobin CO concentration and increasing the reliability of safe operation due to CO gas poisoning in exhaust gas discharged from the combustion device. It is in.

[0011]

The present invention is configured as follows to achieve the above object. That is, the CO safety device for a combustion device according to the present invention includes a CO concentration detection unit that detects the CO concentration in the exhaust gas of the combustion device by a sensor, and from the start of combustion of the combustion device until the sensor outputs a CO detection signal. A blank time measuring unit that measures the blank time of the sensor, and when exposed to the exhaust gas atmosphere during the blank time based on the value of the blank time and the data of the CO detection concentration output from the sensor at the end of the blank time. And a CO concentration estimating calculation unit for estimating and calculating blood hemoglobin CO concentration taken into the blood, and taking in the blood when exposed to a CO gas atmosphere having the detected CO concentration based on the CO concentration detection data after a lapse of a blank time. The blood hemoglobin CO concentration is calculated, and the calculated blood hemoglobin CO concentration is changed to the blood hemoglobin CO estimated concentration determined by the CO concentration estimation calculation unit. And CO concentration total calculator for calculation, the CO
An alarm output unit that outputs an alarm signal when the blood hemoglobin total CO concentration determined by the concentration total calculation unit exceeds a predetermined alarm reference value.

Further, the CO safety device for a combustion device according to the present invention is characterized in that the blood hemoglobin CO concentration taken into the blood in each CO concentration atmosphere is such that the blood hemoglobin CO concentration when exposed to the CO gas atmosphere of each concentration is reduced. The time until the hemoglobin CO concentration reaches the alarm reference value is represented by T, and the time of exposure to the CO gas concentration is represented by t, and the ratio of t to T is given by a value of t / T. Have been.

[0013]

When the combustion equipment is operated for combustion, the amount of CO gas generated in the exhaust gas is gradually increased, and when the CO concentration is detected by the sensor, the blank time measuring unit is operated from the start of the combustion operation to the initial detection of the CO concentration. The blank time of is measured. Assuming that the person has been exposed to the CO gas atmosphere during the blank time, the CO concentration estimation calculating unit estimates and calculates the blood hemoglobin CO concentration at which the CO gas is taken into the human blood during the blank time. The CO concentration total calculation unit calculates the blood hemoglobin CO concentration taken into the blood from the CO concentration detected after the lapse of the blank time, and calculates the calculated blood hemoglobin CO concentration.
The blood concentration is integrated with the blood hemoglobin CO estimated concentration obtained by the CO concentration estimation calculation unit, and the blood hemoglobin total concentration is calculated. The alarm output section outputs an alarm signal when the blood hemoglobin total CO concentration reaches a predetermined alarm reference value. By using this alarm signal to warn of CO gas leakage and stop combustion, CO
Safety against gas poisoning is achieved.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. In the description of the present embodiment, the same reference numerals are given to the same names as those in the conventional example, and detailed description thereof will be omitted. In the present embodiment, similarly to the conventional example, the safety against CO gas poisoning in indoor-installed combustion equipment such as a water heater or a water heater is provided, and a CO sensor for detecting the CO gas concentration in the exhaust gas of the water heater 1 11 is provided at a desired position in the exhaust path of the water heater 1.

FIG. 1 shows an example of a block configuration of a CO safety device for a combustion apparatus according to the present embodiment. The CO safety device according to the present embodiment includes a CO concentration detecting unit 12, a blank time measuring unit 13,
An O concentration estimation operation unit 16, a CO concentration total operation unit 17,
It has an alarm output section 14 and a combustion stop section 15.

The CO concentration detector 12 detects the CO concentration at every unit detection time t during the combustion operation of the water heater 1. For example, when the unit detection time t is 10 seconds, the CO detection value from the CO sensor 11 is sampled every second, and the average of the sampled values is used as the CO concentration detection value of the unit detection time t for the blank time. Measurement unit 13 and CO concentration estimation calculation unit 16
And to the CO concentration total calculation unit 17.

The blank time measuring section 13 sets a timer 18 at the start of the combustion operation, and measures a blank time t ₀ until the CO concentration detecting signal is applied from the CO concentration detecting section 12.
The blank time measurement unit 13 adds the signal of the measurement time t ₀ to the CO concentration estimation calculation unit 16.

The CO concentration estimation calculating section 16 calculates the blank time t.
_{Based on} the value of ₀ and the detected CO concentration data output from the CO sensor 11 at the end of the blank time, blood taken into the blood when it is assumed that a person has been exposed to the exhaust gas atmosphere during the blank time. The medium hemoglobin CO concentration is calculated as described later to calculate an estimated calculation value ER ₀ , and the calculated value is sent to the CO concentration total calculation unit 17.

The CO concentration total calculation unit 17 calculates the estimated calculation value of the blood hemoglobin CO concentration taken into the human blood during the blank time by the CO concentration estimation calculation unit 16 and calculates the calculated value every time t after the blank time elapses. calculates the blood hemoglobin concentration of CO that is incorporated into the blood when a person in the atmosphere of the CO concentration in the exhaust gas to be detected is exposed, blood hemoglobin CO after blank time to the estimated calculation values ER ₀ The blood hemoglobin total CO concentration TR is calculated by sequentially integrating the concentrations.
That is, assuming that the time at which the blood hemoglobin CO concentration taken into a person's blood when the person is exposed to the CO gas atmosphere of each concentration reaches the alarm reference value is T, the time T at which the alarm reference value is reached is depends CO concentration in the exhaust gas as shown in the simulation curve in FIG. 4, for example, when the alarm reference value of blood hemoglobin CO concentration 25%, when the CO concentration in the exhaust gas of 3000ppm at time T _a reached, when the 2000ppm at time T _B, 1000PP
In the case of m, it arrives at time T _C. From the relationship between the alarm reference value arrival times T _A , T _B , and T _{C of the} blood hemoglobin CO concentration and the CO concentration in the exhaust gas, as shown in FIG. C
The relationship with each time T when the O concentration reaches the alarm reference value is obtained. Thereby, the time T until the blood hemoglobin CO concentration reaches the alarm concentration is represented by, for example, an E curve in FIG. Here, CO represents the concentration of CO in the exhaust gas in ppm. As described above, blood hemoglobin C
Assuming that the time during which a person is exposed to the atmosphere of each CO gas concentration at which the O concentration reaches the alarm reference concentration is t, the ratio of t to T, t /
Assuming that T is ER, for example, when the CO gas atmosphere concentration of the exhaust gas is 3000 ppm, the blood hemoglobin CO concentration taken into the blood when exposed to this atmosphere for the unit detection time t is the blood hemoglobin concentration. ratio dangerous concentrations of CO concentration, ER = t / T _a becomes, 1000 ppm
When the, the ER = t / T _C. That is, ER represents the blood hemoglobin CO concentration taken into the blood during the unit detection time t as a value of the ratio to the dangerous concentration. By integrating this blood hemoglobin CO concentration ER based on the detected CO gas concentration value per unit detection time t, the total blood hemoglobin CO concentration when exposed to an atmosphere of each CO concentration is dangerous. It is determined by the ratio value to the reference density.

As shown in FIG. 8, when the combustion operation is started and the CO concentration in the exhaust gas is detected, it is assumed that the concentration at the time of the initial detection is a constant concentration from the start of the combustion operation. When it is assumed that a person has been exposed to the atmosphere, the time until the blood hemoglobin CO concentration taken into the blood reaches the dangerous reference concentration is defined as T _0, and the blood hemoglobin is taken up into the blood in the atmosphere having the constant CO gas concentration. The blood hemoglobin CO concentration obtained is determined by the value of the ratio t ₀ / T ₀ of t ₀ to T ₀ , where the time during which a person is exposed during the blank time from the start of combustion to the initial detection time is t ₀ . However, the blood hemoglobin CO concentration actually taken into the blood is shown in FIG.
As shown in (1), the blood hemoglobin CO concentration gradually increases from the start of combustion, and the blood hemoglobin CO concentration can be approximately obtained from the value of the area of the triangle ABC. That is, the blood hemoglobin CO concentration taken into the blood during the blank time is ER ₀
Then, ER ₀ is obtained by, for example, ER ₀ = t ₀ / 2T ₀ . Thus, the total blood hemoglobin CO concentration TR is represented by TR = ER ₀ + ΔER _n , and when TR = 1, the blood hemoglobin CO concentration becomes 25%, which is the risk reference concentration. .

The alarm output section 14 is provided with a blood hemoglobin total CO calculated by the CO concentration total calculating section 17.
When the concentration TR exceeds an alarm reference value given in advance (for example, blood hemoglobin CO concentration 25%), an alarm signal of the first signal A is added to the alarm means 19 and the signal is sent to the combustion stopping unit 15 at the same time. Add. The combustion stop unit 15 receives the signal and closes the gas valve 20 to stop the combustion operation. Alarm means 19
, For example, blinks a lamp or the like, emits a sound such as a buzzer, or the like, to notify the danger. When the blood hemoglobin CO concentration is lower than the dangerous concentration, for example, when the blood hemoglobin CO concentration reaches 15%, the alarm output unit 14 outputs an alarm signal of the second signal B as a preliminary alarm reference value. Then, the alarm means 19 and the combustion stopping unit 15 perform respective operations based on the second signal B.

This embodiment is configured as described above.
Next, based on the flowchart of FIG.
The safety operation of the safety device will be described. First, at step 100, it is determined whether or not the combustion operation switch of the water heater is turned on. When the switch is on, at step 101, the blood hemoglobin CO concentration TR calculated at the previous combustion operation is set to an alarm reference value (blood hemoglobin CO2). Determine whether the concentration is less than 1.0, which is the concentration at which the concentration becomes 25%.
If it is smaller, it is determined in step 102 whether or not the flow sensor 21 has detected the flow rate. If the flow rate is detected, the count of the timer 18 is started in step 103 assuming that the combustion operation has been started. In step 104, it is determined whether or not the CO sensor 11 has stably detected CO in the exhaust gas.
When the detection signal of the concentration is outputted, measures the idle time t ₀ from the timer count start until the CO early detected at step 105. In step 106, the estimated calculated value ER ₀ of the blood hemoglobin CO concentration during the blank time is
_The calculation is performed as ₀ = t ₀ / 2T ₀ .

Next, in step 107, the estimated hemoglobin concentration ER _{0 is changed} to the blood hemoglobin CO concentration E after the blank time.
R is integrated for each time t to calculate total hemoglobin CO in blood.
The density TR is determined by TR = ER ₀ + ΣER _n .

Next, in step 108, the blood hemoglobin total CO concentration TR is compared with a preliminary alarm set value B lower than the dangerous concentration, and if it is smaller than the set value B, the next step 110 is performed. In this step 110, a predetermined time (for example, 60 minutes) which is considered to be safe even when a person is exposed to a low-concentration CO gas atmosphere in which the CO concentration in the exhaust gas is not detected by the CO sensor 11 is set. It is to determine whether or not it is safe based on the duration of combustion of the water heater.

In step 110, it is determined whether or not the combustion time from the start of hot water supply is within a predetermined time (eg, 42 minutes). If it is within the predetermined time, the combustion operation is continued because there is a margin until the dangerous concentration is reached. . If the faucet 9 is closed in step 111 and the off signal is output from the flow rate sensor 21 while the combustion operation is being continued, the combustion operation is stopped in step 112. Then
In step 113, counting of the operation stop time is started.

When the combustion of the water heater 1 is stopped, the CO gas in the room leaks through a small gap to the outside during the combustion stop period, and the CO gas concentration in the room decreases. When the indoor CO gas concentration decreases, the blood hemoglobin total CO concentration TR attenuates in accordance with the amount of decrease in the CO gas. Therefore, in this example, the blood hemoglobin total C
The attenuation constant of the O concentration TR is obtained, and the attenuation correction of the blood hemoglobin total CO concentration TR is performed from the attenuation constant. Here, assuming that the attenuation constant is Q, the attenuation constant Q is Q = e
^It is expressed by ^-KtL , where K is the assumed number of ventilations per hour during the stop of combustion, and given by experience, for example, a value of 0.2 for a highly airtight apartment. Further, tL is the time from when the combustion is stopped to when the combustion operation is started again. In this way, when the combustion is stopped, the blood hemoglobin total concentration TR is attenuation-corrected to prepare for the next combustion operation.

If it is determined in step 108 that the blood hemoglobin total concentration TR is equal to or higher than the preliminary alarm set value B,
In step 109, the fan 2 is forcibly rotated to bring it in a direction to increase the combustibility. At step 115, it is determined again whether or not TR is smaller than the risk reference value 1.0.
That is, if 1.0>TR> B, the combustion operation is stopped in step 116, and a signal B corresponding to the preliminary alarm value is output in step 117. At step 118, the stop time is counted.
R is attenuated, and a reset operation is performed in step 119 to return the rotation of the fan 2 to the normal mode of normal rotation, and the sequence program is reset to prepare for the next combustion operation.

If it is determined in step 101 that the blood hemoglobin total CO concentration TR calculated during the previous combustion operation is equal to or higher than the alarm reference concentration 1.0, the process proceeds to step 12.
At 0, the combustion operation is immediately stopped, and at step 121, an alarm signal of signal A is sent, and a display is performed by, for example, blinking of a lamp or the like. In step 122, the combustion stop time is, for example,
It is determined whether or not four hours have elapsed. If it is determined that four hours have not elapsed, the combustion operation is not performed. After 4 hours, it is assumed that the CO gas in the room leaks out from the gap and the CO gas in the room becomes completely zero. In step 123, the value of the blood hemoglobin total CO concentration TR is reset to zero.
In addition, the sequence program is reset to prepare for the next combustion operation.

According to this embodiment, from the start of combustion operation, CO 2
Estimated calculated value ER0 of blood hemoglobin CO concentration taken into blood during the blank time until concentration detection ER ₀ is calculated as blood hemoglobin CO concentration ER taken into blood after the blank time has elapsed
And the blood hemoglobin total C
Since the CO safety operation of the water heater is controlled on the basis of the O concentration TR, it is possible to accurately and accurately determine the danger of the CO concentration, thereby greatly improving the safety against CO gas poisoning. be able to.

In this embodiment, since the blank time from the start of combustion is measured, even if the initial detection level of the used CO sensor varies, the blood hemoglobin CO concentration can be detected in accordance with the variation. The operation will be performed.

For example, when the specification value of the minimum CO concentration detection level of the used CO sensor is 1000 ppm, there is a variation in the sensor. Therefore, when the CO sensor is actually used, the CO gas before 1000 ppm, for example, 600 ppm of CO is used. C in concentration
In some cases, an O detection signal may be output. In another sensor, even if the specification value of the lowest CO concentration detection level is the same as 1000 ppm, when actually used, for example, 1400 ppm
If the CO concentration does not reach, a CO detection signal may not be obtained.

In the above case, the minimum CO concentration detection level is 60
Because when the CO sensor of 0 ppm (CO sensor varies towards CO minimum detection level is low) is used the initial detection signal is obtained at t _R point of CO concentration in the exhaust gas 600 ppm, the idle time t _R is The specification value of the minimum CO concentration detection level is shorter than t ₀ when using a CO sensor having a dispersion of 1000 ppm and the estimated calculated value ER ₀ of the blood hemoglobin CO concentration is also smaller. As a result, the time for detecting the actual measurement of the blood hemoglobin CO concentration becomes longer.

Conversely, the lowest CO concentration detection level is 1400
Blank time t _H when a ppm CO sensor (a CO sensor that varies in the direction of higher CO minimum detection level) is used.
As a result, ER ₀ also increases, and as a result, the time required to detect the actual measurement of blood hemoglobin CO concentration is reduced.

As described above, due to the variation of the CO sensor, the blank time changes with respect to t ₀ in accordance with the mode of the variation, and ER ₀ corresponding thereto is calculated.
Or without variation in the CO sensor blank time it was fixed at a constant t ₀ compared with a method to detect the blood hemoglobin CO concentration, it is possible to increase the detection accuracy.

The present invention is not limited to the above embodiment, but can take various embodiments. For example, the above embodiment is used CO sensor 11 as a sensor for detecting the CO concentration, O ₂ sensor or the like indirectly with CO
The concentration may be measured.

Although the CO sensor is provided in the exhaust path of the water heater 1 in the above embodiment, it may be provided in a room where a combustion device such as a water heater is installed.

Further, in the above embodiment, the alarm reference value of the blood hemoglobin CO concentration is set to 25%, but this alarm reference value is arbitrarily set to a value of another different concentration, for example, 15% from the viewpoint of safety. can do.

Furthermore, in the above-described embodiment, the combustion equipment has been described as an example of a gas fired water heater, but the present invention can be applied to a water heater other than the gas fired water heater, for example, an oil fired water heater. Things. Further, the present invention is applied as a CO safety device for various combustion devices using gas or oil, such as a bath kettle and a heater other than a water heater.

Further, in the above embodiment, the unit detection time t of the CO concentration is set to 10 seconds, but this time can be set arbitrarily. In the above embodiment, sampling is performed every second. The detected values of the CO sensor are averaged, and the average value is used as the CO concentration. However, the average value is not necessarily limited to the embodiment.

[0040]

[Effects of the Invention] The present invention provides a method for estimating the calculated value of blood hemoglobin CO concentration taken into the blood during the blank time from the start of combustion operation of the combustion equipment to the detection of the CO concentration. It is configured to integrate the blood hemoglobin CO concentration taken into the device, and based on this integrated blood hemoglobin total CO concentration, the CO safety operation of the combustion device is controlled. In addition, it can be performed with high accuracy, and the safety against CO gas poisoning can be significantly improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a combustion device field CO safety device according to the present invention.

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

FIG. 3 is an explanatory diagram showing a relationship between a CO concentration and a time until the blood hemoglobin CO concentration reaches a dangerous concentration.

FIG. 4 is a simulation graph for calculating a time T at which a blood hemoglobin CO concentration becomes a dangerous reference concentration when exposed to a predetermined concentration of CO gas.

FIG. 5 is a schematic configuration diagram of a general water heater as a combustion device.

FIG. 6 is an explanatory diagram of an indoor installation state of the combustion equipment.

FIG. 7 is an explanatory diagram showing a rising state of a sensor output of a CO sensor.

FIG. 8 is an explanatory diagram showing an integrated state of blood hemoglobin CO concentration taken into blood.

[Explanation of symbols]

 6 Control device 11 CO sensor 12 CO concentration detection unit 13 Blank time measurement unit 14 Alarm output unit 16 CO concentration estimation calculation unit 17 CO concentration total calculation unit 21 Flow rate sensor

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Masato Kondo 3-4 Fukamidai, Yamato-shi, Kanagawa Prefecture Gaster Co., Ltd. (56) References JP-A-5-26438 (JP, A) 46164 (JP, U) Hira 5-45441 (JP, U) (58) Fields investigated (Int.Cl. ⁶ , DB name) F23N 5/24 107 F23N 5/00 F23N 5/26 101

Claims (2)

(57) [Scope of request for utility model registration] 1. A CO concentration detecting section for detecting a CO concentration in exhaust gas of a combustion device by a sensor, and a blank time for measuring a blank time from the start of combustion of the combustion device until the sensor outputs a CO detection signal. A measurement unit, based on the value of the blank time and the data of the CO detection concentration output from the sensor at the end of the blank time, the blood taken in the blood when exposed to the exhaust gas atmosphere during the blank time A CO concentration estimating calculation unit for estimating and calculating the hemoglobin CO concentration;
The blood hemoglobin CO concentration taken into the blood when exposed to the O gas atmosphere is calculated, and the calculated blood hemoglobin CO concentration is integrated with the estimated blood hemoglobin CO concentration obtained by the CO concentration estimation calculation unit. And a warning output unit that outputs a warning signal when the blood hemoglobin total CO concentration determined by the CO concentration total calculation unit exceeds a predetermined alarm reference value. CO safety device. 2. The blood hemoglobin CO concentration taken into the blood in each CO concentration atmosphere is the time required for the blood hemoglobin CO concentration to reach the alarm reference value when exposed to the CO gas atmosphere of each concentration. 2. The CO safety device for combustion equipment according to claim 1, wherein T is a value of a ratio t / T between t and T, where T is the time of exposure to the CO gas concentration.