JPS58176540A - Discriminating apparatus of gas - Google Patents

Abstract

PURPOSE:To discriminate gaseous hydrocarbon not containing gaseous carbon monoxide from the exhaust gas of a motor car, by providing a gas sampling means and a detector for detecting the concentration of the gaseous hydrocarbon of a part of sampled gas and also providing a detector for detecting the gaseous carbon monoxide of residual gas. CONSTITUTION:Sample gas sent from a pump is flowed into a duct 30 and the flow rate is adjusted by a throttle valve 31. Then, the flow rate is measured by a flowmeter 32 and is flowed into a duct 33. A part of the inflow sample gas is flowed into a hydrogen flame ionizing detector 28 and the concentration of total hydrocarbon gas is measured. The residual sample gas flowed into the duct 33 is flowed into a gaseous hydrogen monoxide detector 29 through a duct 34 and the concentration of the gaseous hydrogen monoxide is measured. Gaseous hydrogen is flowed into the detector 28 from a hydrogen bomb 36 through a duct 38. Whether it is gaseous hydrocarbon (town gas) not containing the gaseous carbon monoxide of the exhaust gas of a motor car, is discriminated by comparing the measured value of the detector 28 with that of the detector 29.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas identification device, and more particularly to a gas identification device for continuously distinguishing between hydrocarbon gas not containing oxidized carbon gas and automobile exhaust gas.

When detecting gas leaks from underground pipes that supply city gas from the ground using a detector without polling, it is necessary to distinguish between gas leaks from the exhaust gas from the 11 vehicles, etc. It is necessary.

Conventionally, in order to check whether gas is leaking from buried pipes used to supply city gas, methods such as road polling, drilling small holes to detect odors, and detection using heatable gas detectors have been used. are doing. However, in recent years, as road construction has become more sophisticated, polling has become difficult, so as an alternative investigation method, it is necessary to discover leaks without polling, and a hydrogen flame ionization gas detector is used. there was. Leak investigation methods are being used. This method continuously detects trace amounts of hydrocarbons in city gas that leak through very small gaps in the road surface while driving on the road. However, the atmospheric I/c is
Since it contains a considerable amount of exhaust gas, it is necessary to be able to continuously identify these gases.

In the related prior art, a device equipped with a hydrogen flame ionization detector in one conduit and a hydrogen flame ionization detector in the other conduit with a device for removing hydrocarbon gases other than methane gas is used to aspirate a sample continuously. Gas is divided into two pipes and introduced, and the output difference between both detectors is measured.

The sample gas is identified by In such prior art, devices for removing hydrocarbon gases other than methane gas are complex and expensive, and require a large amount of power supply, resulting in large size.

It is an object of the present invention to provide an inexpensive gas identification device that solves the above-mentioned technical problems, has a simple configuration, and can quickly notify the location of a city gas leak.

In order to achieve this purpose, as a result of intensive research, -
An in-vehicle gas identification device that distinguishes between hydrocarbon gas that does not contain carbon oxides and automobile exhaust gas, which includes a sampling means for sampling the gas to be identified, and measures the hydrocarbon gas concentration of some of the sampled gases. It has now been possible to develop a gas identification device comprising detection means comprising a flame ionization detector to measure the carbon monoxide gas concentration of the residual gas and a carbon monoxide gas detector to measure the carbon monoxide gas concentration of the residual gas. According to such a gas identification device, it becomes possible to continuously identify hydrocarbon gas that does not contain carbon oxide and automobile exhaust gas. In addition, compared to the prior art device described above, it is inexpensive because it does not require a device for removing hydrocarbon gases other than methane gas, and
ffl is simple, it is easy to handle, and it is possible to quickly and accurately know the location of a city gas leak.

FIG. 1 is a simplified cross-sectional view for explaining one embodiment of the present invention. A conduit 2 for supplying city gas is buried in the ground 1. In order to detect from the ground whether there is a leakage of city gas from this conduit 2,
A gas identification device 4 according to the present invention is installed in the gas identification device 4 of the present invention. car 3
A probe 5 is attached near the 1f TIIB bumper, and the gas collected from the probe 5 is sent to the subsequent gas identification device 4. As the automobile 3 travels on the ground along the conduit 2, leaking city gas 6 can be continuously identified regardless of the exhaust gas from the automobile.

FIG. 2 is a block diagram schematically showing the gas identification device 4 shown in FIG. 1. Gas identification device M4Fi, sampling means 7 that sucks the gas to be identified from the probe 5, detection means 8 that detects the collected sample gas, and signal processing means 9 that processes the output signal from the detection means 8. and a recording means 1O for recording the processed output signal in accordance with the running speed of the vehicle; a display means 11 for issuing an alarm when city gas 6 is included in the sample gas; and a collection means 7 for these. , detection means 8, signal processing means 9, recording means lO1 display means 1
1 and a power source 12 that supplies power to the 1.

FIG. 3 is a diagram showing the configuration of the collection means 7, and the fourth
The figure is a sectional view of the vicinity of the probe 5 shown in FIG.
Figure #i is a sectional view taken from the section line Y-ma in Figure 4;
FIG. 6 is a cross-sectional view of the vicinity of the tip of the probe 5, and FIG. 7 is a cross-sectional view taken along the section line ``---'' in FIG. The sampling means 7 includes a plurality of probes 5 that suck air near the ground 1, a trap 13 that removes moisture from the sample gas collected from these probes 5, and a trap 13 that removes dirt and dust contained in the sample gas. and a pump 1 for sucking sample gas at a flow rate of, for example, 5e/min.
5, and conduits 16, 17, and 18 that successively connect these. The probes 5Fi are installed at a constant interval within the vehicle width range of the vehicle 3 on which the vehicle 3 is mounted, so that leakage of city gas 6 is detected within the vehicle width range of the ground l on which the vehicle 3 travels. be able to.

The 16 conduits are sequentially branched in parallel and connected to a first connecting pipe 19 and a second connecting pipe 20. Furthermore, the second connecting pipe 20
are sequentially connected in parallel to connection paths 21, 22, and 23 formed in a rectangular plate 25 made of, for example, acrylic resin.

The connecting paths 21 to 23 are formed by forming grooves in a pair of rectangular plates 25a and 25b, and pasting these rectangular plates 25m and 25b with adhesive or the like. The probe 5 is detachably connected to the tip of the connecting path 23 (lower end in FIG. 4) via a joint 24. These connecting pipes 19, 20 and connecting paths 21~
23 refers to the suction ports 5m and 5b of each probe 5.

The diameter, length, etc. are determined so that the suction pressures at 5c and 5d are equal.

Magnets 26m and 26b for adhering to the surface VcVi of the rectangular plate 25b and the bumper of the automobile 3 are attached.

The rectangular plates 25a and 25b have bashibars.

A through hole 27 is formed for fixing the device so that it does not slip off, and this through hole 27 is engaged with a protrusion formed on a base bar or the like. Since the tip VCtri of the connecting pipe 23 and the joint 24 are provided, the probe 5 can be easily removed when the gas weaving device 4 is not in use.

In order to improve the detection sensitivity of city gas 6, the tip gIs of the probe 5 is kept as narrow as possible with the ground 1, and is closed with a stopper 5eVc to prevent dust, dirt, and water from being sucked in. Suction ports 5a to 5d are formed at equal intervals in the same direction of the probe 5 at intervals of, for example, 20 mm from the tip of the probe 5. The suction ports 5a to 5d are formed to have a diameter of 1 mm, for example.

FIG. 8 is a diagram showing the configuration of the Vi detection means 8. Detection means 8#''i, roughly speaking, includes a hydrogen flame ionization detector 428 that measures the total hydrocarbon gas concentration in the sample gas fed by the pump 15, and a monoxide detector 428 that measures the carbon monoxide gas concentration in the sample gas. The sample gas sent from the pump 15 of the sampling means 7 flows into the conduit 30, the flow rate is adjusted by the throttle valve 31, the flow value is measured by the flow meter 32, and the sample gas is sent to the conduit 33. Inflow ◇ A part of the sample gas that has flowed into the conduit 33 flows into the hydrogen flame ionization detector 28 and the total hydrocarbon gas concentration is measured. 3
The carbon monoxide gas is measured by flowing into the carbon oxide gas detector 29 through a conduit 34 branched from the carbon monoxide gas detector 29. - Since the carbon oxide gas detector 29 is a detector based on the principle of constant potential electrolysis, the output signal is delayed by 3 to 5 seconds compared to the measurement time of the hydrogen flame ionization detector 28.

The branch pipes 30a and 33a are connected to the conduit 30.33, respectively, and the tips of the branch pipes 30a and 33a are connected to FAIVCt.
RI valves 35a and 35-b are not provided and are used for sampling sample gas, etc. Hydrogen gas flows into the hydrogen flame ionization detector 28 from a cartridge-type hydrogen pump 36 through a conduit 38 . A conduit 38ct-1, a pressure reducing valve 37, a pressure gauge 39, and a solenoid valve 40 for adjusting the pressure of hydrogen gas are provided. .

Table 1 shows an example of the composition of city gas, so-called 13A gas, which is obtained by vaporizing liquefied natural gas. As is clear from the Broom 1 table, this 13A gas has #:t.

- Does not contain carbon oxide gas. Vc in automobile exhaust gas
Since carbon monoxide gas and the like are included together with hydrocarbon gas, by comparing the measured values from both the detectors 28 and 29, it can be determined whether the gas is - hydrocarbon gas that does not contain carbon oxide gas or not. , that is, it is possible to identify whether it is city gas 6 of t) 13A or automobile exhaust gas.

@1 Table 2 shows the total hydrocarbon gas concentration measured by the hydrogen flame ionization detector 28 and -carbon oxide gas detection WA29
It is determined whether the sample gas is city gas 6 or automobile exhaust gas based on the measured value of the carbon monoxide gas concentration measured by the method. Note that in Table 2, the 0 mark represents a measured value above a certain level, and the X mark represents a measured value below a certain level.

Table 2 As shown in Table 2, the inventor conducted the following experiment in order to confirm that sample gases could be identified. First, city gas and exhaust gas from an IDR vehicle were collected in a gas bag, diluted with the atmosphere until the sample gas concentration was as shown in Table 3, and used as sample gas. This sample gas was sucked through the probe 5 of the sampled biofilm 7, and the total hydrocarbon gas concentration and carbon monosulfide gas concentration of this sample gas were measured by both the detectors 28 and 29. Table 3 shows the results of this measurement.

Table 3 The results in Table 3 are in good agreement with the ¥g2 table. Therefore, according to the gas identification device @4Vc, is it accurate? 11
Indeed, it is possible to distinguish between automobile exhaust gas and leaked city gas (13A) 6.

FIG. 9 is an electrical circuit diagram of the signal processing means 90.

The signal processing means 9 roughly includes a circuit 41 for processing the output signal from the hydrogen flame ionization detector 28, a circuit 42 for processing the output signal from the carbon oxide gas detector 29,
a buzzer circuit 43 that sounds a buzzer when the hydrogen flame ionization detector 28 is in a misfire state in response to an output signal from the hydrogen flame ionization detector 28; a timer circuit 44 that generates a pulse with a negative period; and a power supply 12. Power from circuit 41
- 44, and a circuit 45 that energizes the circuits 44 to 44. In the circuit 41,
A variable resistor 46 for setting the gain of the output signal from the hydrogen flame ionization detector 28, an amplifier circuit 47 for amplifying the output signal, and an indicator 48 for displaying the output signal subsequent to the amplifier circuit 47VC. , a threshold circuit 49 following the indicator 48, and a buzzer circuit 5o that sounds a buzzer when the output signal exceeds the discrimination level of the threshold circuit 49, and between the variable resistor 46 and the amplifier circuit 47. is interlocked with the open/close switch 51 of the solenoid valve 40 of the hydrogen gas cylinder 36.

A switch 52 is provided. After noise and the like are removed from the output signal from the hydrogen flame ionization detector 28 by the threshold circuit 49, it is outputted to the recording means IO and the display means 11Vc.

The circuit 42ij is constructed in the same way as the circuit 41 and 11, and the output signal from the carbon oxide gas detector 28 is connected to a variable resistor 53V.
c is derived, is amplified by the amplifier circuit 55 via the switch 54, is derived to the indicator 56, and is output to the threshold circuit 57Vc.
It is derived, level-discriminated, and derived to the buzzer circuit 58, as well as recording means! ( ) and display means 11 [# are displayed. In the buzzer circuit 58, a buzzer sounds when -carbon oxide gas is present at a discrimination level or higher.

The timer circuit 44 uses, for example, 1
An output signal from the valve generation circuit 59 that generates timing pulses at a fixed interval of ~5 seconds is outputted to the relay switch 61 via the relay fill 60, and this pulse signal is outputted to the relay switch 61.
ill! Recording means lO and display means 11rc are derived.

It consists of a recording means lO#i, a recorder for recording output signals from the hydrogen flame ionization detector 28 and carbon monoxide gas detector 29 processed by the signal processing means 9, and the timer circuit 44. This recorder has a function of setting the feeding speed of the chart paper to a constant speed or a speed synchronized with the traveling speed of the 11 vehicles 30. For example, chart paper is 4 cm for every 11) Om traveled by a car, and Fi
2cm, therefore, on the chart paper, 1/2
Recordings are made at a scale of 500″! or 1150 QQ.

FIG. 10 is a graph showing measurement results recorded in the recording means 10 using, for example, a two-pen recorder. This graph shows the output signals from the processing means 90 and the amplification circuits 47.55 times the timer w! r43 both detectors 28.
By correcting the output time difference of 29, and taking the elapsed time from the start of the measurement surface as the horizontal axis, the total hydrogen oxide concentration and -carbon oxide gas concentration from the hydrogen flame ionization detector 28 and the carbon monoxide gas detector 29 are calculated. It is expressed on the vertical axis. The gas sifting device 4 is mounted on a 1cll car 3, which is running at a speed of 20 to 30 km/h on a 3Fi car. After starting the measurement,
At time ti'''cVi, the total hydrocarbon gas concentration shown by the solid line in the figure shows a peak value, for example l Oppm, shown by the arrow 62, and the carbon monoxide gas concentration shown by the broken line does not have a peak value.At time tl , -The carbon oxide gas concentration indicates the carbon monoxide gas concentration in the atmosphere, for example, 2 to 3 pp+n, and therefore, a leak of city gas 6 is detected at the passing point at this time.In this way, the speed of 20 to 30 km/h
The carbon monoxide gas detector 29 installed in a car traveling at 100 mph normally detects a concentration of carbon monoxide gas in the atmosphere of 2 to 3.
The values in ppm are shown. Furthermore, at time t2, the total hydrocarbon gas concentration has a peak 63, for example 7 ppm.
It shows. At this time t2, the -carbon oxide gas concentration has a peak 64 and is, for example, 19 ppm. Therefore, at the passing point at time t2,
This means that exhaust gas from one vehicle has been detected.

FIG. 11 is a block diagram showing the iUL of the display means 11. The display means 11 is an analog/digital conversion circuit FI.
1165, a memory circuit 66, a logic circuit 67, a distance calculation circuit 68, and a display circuit 69. Each analog output signal derived from the signal processing means 9 is converted into a digital signal 8 by an analog-to-digital conversion circuit 65 and output to a memory circuit 66 and a distance calculation circuit 68. The memory circuit 66 stores the peak values of both the outputs from the hydrogen flame ionization detector 28 and the carbon monoxide gas detector 29, and also stores the signal '+V' from the timer circuit 44.
c Correct the response time difference between the following surface detectors 28 and 29.

Based on the signal 5j input from the memory circuit liF, 66 to the logic circuit 67, it is determined whether or not there is a leak of city gas 6, according to the truth table shown in Table 4.

(Hereinafter T margin) Table 4 Table 4 I/i This table is similar to the above-mentioned Table 2, and the logic circuit 67 has the threshold circuit 49 of the primary signal processing means 9 to determine the level of the total hydrocarbon gas concentration. Discrimination h1 threshold circuit 5
7, the carbon monoxide gas concentration is level-discriminated. When the gas concentration is above the discrimination level, the signal rlJ is input from the memory circuit 66. When the gas concentration is below the discrimination level, the signal "0" is input. Each is input from the memory circuit 66. From the logic circuit 67 to the distance calculation circuit 6 according to Table 4
An output signal is derived to 8 and a display circuit 69.

When this output signal rlJ is present, it indicates a leakage of the city gas 6, and the display circuit 69 displays a lamp and makes a 1-day blow. Furthermore, the speed signal of the vehicle 3 and the output signal from the hydrogen flame ionization detector are input to the distance calculation circuit 68, and when the input from the logic circuit 67 is 1, the detection position of all hydrocarbon gases is calculated. The result of this calculation is then output to the display circuit 69. As a result, the display circuit 69 displays the leak position of the city gas 6 along with the lamp display of the music description.

In the above-described embodiment, a 32-meter probe 5 was used to suck atmospheric air from a 30-car-width recess; probes may be used.

As described above, according to the invention, it is possible to continuously distinguish between hydrocarbon gas that does not contain carbon oxide and automobile exhaust gas. Also, compared to the prior art devices mentioned above,
Since it does not require a removal device for hydrocarbon gases other than methane gas, it is inexpensive, has a simple configuration, is easy to handle, and can quickly and accurately determine the leak location of city gas.

[Brief explanation of the drawing]

FIG. 1 is a simplified sectional view showing a leakage investigation situation according to the present invention, and FIG. 2 is an uninvented embodiment of a gas 1 and a separate device 4.
3 is a block diagram showing the structure of the sampling means 7, and FIG. 4 is a cross-sectional view of the vicinity of the probe 5 shown in FIG.
Fig. 5 is a sectional view taken from the cutting plane line v-■ in Fig. 4, Fig. 6 is a sectional view of the vicinity of the tip of the prong 5, and Fig. 1\7 is a sectional view of the 6th
8 is a diagram showing the configuration of the detection means 8, 9M is an electric circuit diagram of the signal processing means 9, and FIG. 10 is a measurement of the recording means IO. A graph showing the results, FIG. 11 is a block diagram showing the fR value of the display means 11. l...Ground, 2...Pipe, 3...Car, 4...
・Gas iron separation device, 5... Prog, 6... Leak city gas, 7... Collection means, 8... Detection means, 9...
8 Processing means, IO...Recording means, ll...Display means, 28...Hydrogen flame ionization detector, 29...-Carbon oxide gas detector agent Patent attorney Kei Nishi

Claims (1)

[Claims] An on-vehicle gas identification device that distinguishes between hydrocarbon gas that does not contain carbon monoxide and automobile exhaust gas, which includes a sampling means for sampling the gas to be identified, and a method for detecting the hydrocarbon gas concentration of some of the sampled gases. A gas identification device comprising: a detection means having a hydrogen flame ionization detector for measuring and a carbon monoxide gas detector for measuring the carbon monoxide gas concentration of the residual gas.