JP4688969B2 - Breath alcohol measurement method - Google Patents

Description

The present invention is a method for measuring the alcohol concentration in the breath accurately and in a short time using a fuel cell type alcohol sensor.

Currently, as a call before departure for buses, taxis, etc., a breath alcohol measuring device using a semiconductor alcohol sensor is used to confirm the presence or absence of drinking. As the number of such offices has increased, there has been a desire for a fuel cell type alcohol sensor with few false positives.

When using a fuel cell type alcohol sensor with high gas selectivity (no reaction with gases other than alcohol) in a bus or taxi establishment that confirms drinking of 100 people or more in 30 minutes, there were the following problems: .

1. The gas response speed takes 20 seconds or more. ... Takes 2 to 4 times longer than semiconductor sensors.

2. Sensor life is extremely short. Replace in about 1 year (1/5 or less of semiconductor sensor)

3. The price of the fuel cell type sensor is high ... more than 20 times that of the semiconductor sensor

4. To increase the measurement accuracy, exhaled gas is sucked into the fuel cell by a pump, but these pumps are likely to malfunction (stop). Therefore, the measured value “0.000 mg / L” may be displayed.

5. When measuring the number of other people, after the high-concentration alcohol of the previous subject was detected, the remaining air elimination time (not affecting the next subject) was required for a while.

Unless these problems were solved, the bus and taxi operators mentioned above could not be used.

Means of the present invention are as follows.
Using two types of sensors, a fuel cell type alcohol sensor and a semiconductor alcohol sensor, the determination of drinking by more drivers can be measured more accurately in a short time.
Specifically, the reaction voltage of the semiconductor sensor after a certain time after the expiration sensor reacts is measured. At that time, if it is measured to be 0.050 mg / L or more, the suction pump for the fuel cell type alcohol sensor is driven at that time. After suction, the power generation voltage of the fuel cell is used as the normal concentration voltage.
Thus, in the case of drinking confirmation of about 100 drivers, the number of times the fuel cell works is suppressed to about several times or less, which is useful for deterioration of an expensive fuel cell having a short life.
In addition, the gas measurement / measurement time per person is almost always measured by the semiconductor sensor, so that processing of several people / minute is also maintained.
In addition, until now, there has been no idiosyncrasies or malfunctions (reactions other than alcohol) due to taking medication for internal diseases.
The semiconductor sensor covers the poor service life and poor responsiveness of fuel cell sensors. In other words, when the drinking level is low and the concentration is low, the measurement is performed only with the semiconductor sensor without using the fuel cell. If you are a driver of a bus or taxi company, the majority of them do not respond to drinking alcohol, you can make a call check with the same speed processing as before.
If a response at the level of alcohol abuser is obtained with a semiconductor sensor, it is measured with an expensive fuel cell sensor with high accuracy and few gas malfunctions (reaction other than alcohol).
This makes it possible to prevent malfunctions and to measure other people.

When both the fuel cell type sensor and the semiconductor gas sensor react, if the mutual gas concentration exceeds ± 20%, for example, it is displayed as a service call.
This also reveals that one of the sensors has deteriorated. However, it is not possible to identify which sensor has deteriorated.
This is displayed when a service call (equipment survey) occurs when a sensor failure occurs, and when alcohol reaction occurs between two different sensors, the measured values are significantly different.
If a service call occurs repeatedly, it can be determined that any alcohol sensor is abnormal.

A pump sensor was installed that would cause a pump error when the pump sucked into the fuel cell did not work.
Specifically, a pump sound generated during suction is picked up by a microphone.
If the pump sound is detected within a certain time from the drive time, the operation is normal. If there is no pump sound or the pump sound is small within that time, a pump error is assumed.
When a pump error occurs, even if there is alcohol power generation in the fuel cell, the measured value is invalid and a service call is displayed.
When the gas suction pump works normally, it makes a very loud sound.
This sound is generated at a certain time after the start of suction. Using this phenomenon, we were able to determine whether pumping was normal by picking up the loudness and timing of the pump.
Of course, when the sound is low, it can be determined that the sound is not normal, so sensing with a microphone sound is certain.

In order to make a large number of breath measurements, a removable breath filter was provided, and a heater that warmed the filter to 40 ° C. or higher was provided.
The filter itself is a measure that prevents hair dust, brim, and saliva from entering the sensor. It became possible to measure.
Residual air of alcohol is immediately absorbed by a liquid such as dew condensation inside the filter and generates alcohol gas forever.
When the filter is warmed to 40 ° C. or higher, dew does not form even when exhaled air of about 30 ° C. and 95% humidity enters, and is discharged outside the measuring device as dry exhaled gas.
Therefore, even when a certain amount of alcohol gas enters the inside of the filter, it will be exhausted in about 2 seconds after the expiration of the next subject (exhalation without alcohol).
Even if the semiconductor sensor reacts, the measured value does not appear if the pump is driven after 2 seconds.
The high concentration alcohol gas accumulated in the exhalation filter is a measure that does not affect the subject who does not have the next drinking reaction.
Since the alcohol gas is absorbed by the condensed moisture, the filter itself is heated to 40 ° C. or more to prevent condensation due to expiration.
Although this effect actually consumes power, it can be measured without waiting for several minutes as the residual air elimination time.

According to the present invention, it is possible to confirm drinking of about 100 or more drivers in 30 minutes while using a fuel cell type sensor.
In particular, there has been no idiosyncratic constitution or alcohol reaction (erroneous reaction) due to the use of drugs for treating internal diseases, and the life of the fuel cell type sensor has been extended more than twice.
Even in offices with many drivers, a single detector can be used for a sufficient number of calls, and maintenance costs can be significantly reduced.

It is a block diagram of this embodiment. It is each sensor response waveform of this embodiment. It is an operation | movement schematic flowchart of this embodiment. It is a pump operation | movement confirmation waveform of this embodiment. It is a pump abnormal operation detection flowchart of this embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<First Embodiment>
FIG. 1 is a configuration diagram of this embodiment. Two types of semiconductor sensors are provided for measuring alcohol in breath, an internal semiconductor sensor and a fuel cell type alcohol sensor.
The fuel cell type sensor is provided with a dedicated suction pump for taking in exhaled air.
Here, on the assumption that a large amount of exhaled air is infused, the exhalation filter 6 is attached to remove hair dust, brim, saliva and so on.
Eighteen heaters were attached to the filter, and the filter was mounted so that residual alcohol gas after the measurement was not absorbed by the condensed moisture.
The exhaled air that has passed through the filter is discharged from the exhalation part discharge port, and at the same time, the alcohol gas concentration is measured by the semiconductor sensor 5.
If a low alcohol concentration is acceptable, the semiconductor sensor concentration display of 5 is displayed as positive.
On the other hand, if it is determined that the alcohol concentration is high, the suction pump 1 is pulled, and exhalation is taken into the fuel cell type sensor 10 to perform accurate measurement.
The generated voltage (power generation voltage) obtained here is calculated more accurately by the control unit 3, and the alcohol concentration is obtained and displayed.
Usually, in the drinking check of the driver of the bus or taxi, since there is no alcohol reaction, the measurement is completed with only the semiconductor sensor without consuming the fuel cell type sensor.

More specific description will be given below.

FIG. 2 explains the present invention from when the exhalation is injected until the suction pump works and the fuel cell type sensor operates.
The vertical axis in the figure indicates the voltage at the time of reaction of each breath sensor semiconductor sensor and fuel cell type sensor, and the horizontal axis indicates time.
First, when exhalation is injected, the exhalation sensor voltage 13 increases. Here, the voltages of the semiconductor sensors 14 and 15 when n seconds elapse after the control unit detects the rise are detected. Here, comparison is made with the pump operation determination concentration voltage of 16, which is the reference value of the alcohol concentration.

If the semiconductor sensor voltage is 2 level of 15, the n-second elapsed time voltage is 12 measurement voltage 2 and is lower than the determination voltage of 16, so that the measurement voltage 2 is not pulled. Display the required concentration.
On the other hand, when the measurement voltage 1 of 11 exceeding the level of the reference value 16 is obtained like the semiconductor sensor voltage 1 of 14, the pump of 17 is immediately operated.
Then, the exhaled breath sample sucked into the fuel cell type sensor reacts inside the battery to generate 8 fuel cell sensor voltage.
From this waveform, a more accurate concentration is measured and displayed by the following calculation.

FIG. 3 is a flowchart of the actual determination unit of the present invention.
In general, the concentration in exhalation is 0.050 mg / L or less, but a small amount of alcohol called noise is contained in juice, sweets, etc.
Therefore, 0.050mg / L or less is set as a cutoff value, and the display is forced to 0.000mg / L and "0" is displayed.
If the criterion is 0.030 mg / L, the measurement will be completed at “0.000 mg / L” without drawing the suction pump as shown in the flowchart.
If it exceeds 0.030 mg / L, the suction pump is pulled and the process proceeds to voltage measurement of the fuel cell.
Therefore, if it is less than 0.050 mg / L, the display is set to “0.050 mg / L”, and if it is exceeded, it is displayed according to the measured value.
In addition, since there are two different types of sensors, it can be determined that the two types of sensors are operating normally if the mutual density calculation is an error of ± 20%.
If an error of ± 20 or more has occurred, it is possible that some sort of sensor sensitivity degradation has occurred, and a display such as “maintenance call” can be lit.

FIG. 4 shows a method for detecting a pump error.
Whenever the fuel cell type sensor is driven, the suction pump is pulled.
If the suction pump is not pulled for some reason, it should be “0.000 mg / L”, which should be determined as “0.300 mg / L” drinking.
In other words, if the pump is not aspirated, this is a phenomenon that occurs because the exhaled sample is not injected into the sensor, and should never be present.
As a countermeasure, pick up the sound when the pump is pulled with a microphone.
The sound at the time of drawing is generated in a time range determined by the suction drive signal.
The generated sound is a sound that metal collides with and can be distinguished from surrounding noise.
When there is a microphone sound in the range of t1 to t2 shown in the figure at a volume higher than a certain level, this indicates that the pump has operated normally.
If there is no microphone sound between t1 and t2, it is determined that there is a pump error, indicating that the fuel cell voltage cannot be obtained normally.

FIG. 5 is a flowchart for determining whether or not the pump has normally operated.

DESCRIPTION OF SYMBOLS 1 Suction pump 2 Exhalation part discharge part 3 Control circuit 4 Heater cable 5 Semiconductor sensor 6 Exhalation filter 7 Exhalation part inlet 8 Exhalation part filter heater 9 Joint part 10 Fuel cell type sensor 11 Measuring point voltage 1 by semiconductor sensor
12 Measuring point voltage by semiconductor sensor 2
13 Breath sensor voltage 14 Semiconductor measurement voltage 1
15 Semiconductor measurement voltage 2
16 Pump operation determination concentration voltage (semiconductor sensor voltage)
17 Pump operation waveform 18 Fuel cell type sensor voltage 19 Pump operation detection microphone 20 Pump operation detection microphone signal

Claims (2)

  A method for measuring exhaled alcohol, wherein a service call is displayed when a measured value by a semiconductor alcohol sensor and a measured value by a fuel cell type alcohol sensor exceed a predetermined difference. It has a semiconductor alcohol sensor, a fuel cell type alcohol sensor, and a controller .
The control unit displays a service call on a display unit when a measured value by the semiconductor alcohol sensor and a measured value by the fuel cell type alcohol sensor exceed a predetermined difference. vessel.

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