JPS63180833A - Preprocessor for gas analysis - Google Patents

Abstract

PURPOSE:To enable accurate and efficient gas analysis with quick cooling of a filter, by providing a switching means to supply a cooling fluid to be used in a dehumidifier of a sample gas to the filter after being subjected to a regeneration processing by heating of the filter. CONSTITUTION:In the process of sampling a sample gas, fine particles are removed with a filter M2 from a sampled gas M1 and moisture is removed with a dehumidifier M4 therefrom. With such an arrangement, a gas analyzer M6 is protected from fine particles and gas components are further measured accurately. When fine particles accumulated in the filter M2 are to be removed to meet requirements, i.e. clearing the clogging of the filter M2 and others, the filter M2 is heated by a heating means M5 to remove fine particles or the like. Thus, the filter M2 is regenerated. Upon the end of the heating treatment, a cooling fluid M3 for cooling the dehumidifier M4 is supplied by a switching means M7 to the filter M2 for gas analysis. Thus, the filter M2 is cooled quickly thereby enabling the starting of gas analysis as early as possible.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a pretreatment device for sample gas supplied to a gas analyzer that analyzes the concentration of exhaust gas from an internal combustion engine, and particularly The present invention relates to a pretreatment device that performs heating regeneration treatment of a dust removal filter.

[Prior art] When analyzing exhaust gas from an automobile internal combustion engine, etc., in order to detect the components of the exhaust gas as a sample gas, it is necessary to perform dehumidification to remove moisture, which particularly affects infrared analysis. There is.

Furthermore, since the exhaust gas contains carbon particles, oil mist, etc., it is necessary to remove these in consideration of their influence on the analyzer.

For this reason, some pretreatment devices for exhaust gas and the like are equipped with a filter for removing carbon particles, oil mist, etc., and a cooling device for dehumidification. As such a device, some of the applicants have already applied for practical application in 1986-13.
No. 8968 and Utility Model Application No. 14803/1983 have been filed.

The above-mentioned Japanese Utility Model Application No. 60-138968 cools air using a portex tube, cools exhaust gas with the cooled air, condenses moisture in the exhaust gas, and removes the moisture. In addition, the above-mentioned Utility Model Application No. 14803/1983 is equipped with a filter to capture particulates in the gas, and also measures the pressure difference on both sides of the filter to determine when it is time to regenerate the filter. The filter is regenerated by heating the filter as it is.

[Problems to be solved by the invention] If these techniques are combined, fine particles and moisture in the sample gas to be measured can be removed, but in particular, since the filter is heated in its original state, Even if you try to use the filter immediately after heating the filter to remove particulates, if the sample gas is passed through the filter while it is still hot, the carbon monoxide and hydrocarbons in the sample gas will undergo an oxidation reaction. This will cause accurate measurement of gas components. In addition, the dehumidification capacity of the heat exchanger located downstream of the filter is reduced. Therefore, after the heat treatment, gas components could not be measured until the filter was cooled. The above-mentioned Japanese Utility Model Application No. 14803/1983 also discloses an example in which a fan is used to cool the device in order to speed up cooling, but the cooling capacity is not sufficient.

For this reason, it was necessary to install two filters and switch to another filter during cooling, or to stop measurement until cooling, resulting in an increase in the number of parts in the device, higher costs, and longer measurement times. This was a time-consuming process.

SUMMARY OF THE INVENTION The present invention aims to solve the above problems and employs the following configuration.

[Means for Solving the Problems] That is, the gist of the present invention is to provide: a filter M2 that performs a filtration process on the sample gas M1; A dehumidifier M4 that performs dehumidification processing, and a heating means M5 that heats the filter M2, and the filter M2 and the dehumidifier M are provided in the sample gas collection process.
4, the sample gas M1 processed by the gas analyzer M
6, and is configured to heat the filter M2 by the heating means M5 in the filter regeneration process, further comprising: after the filter regeneration process, the gas discharged from the dehumidifier M4; The flow path of the cooling fluid M3 before being supplied to the filter M3 or the cooling fluid M3 before being supplied to the dehumidifier M4 is switched.
This pretreatment apparatus for gas analysis is characterized in that it is provided with a switching means M7 for supplying gas to gas.

[Operation During the sample gas collection process, particulates are removed from the sample gas M1 by the filter M2, and moisture is removed by the dehumidifier M4. This protects the gas analyzer M6 from particulates and allows more accurate measurement of gas components.

If the filter M2 is clogged or if it is desired to remove particulates accumulated on the filter M2, the filter M2 is heated by the heating means M5 to remove the particulates. In this way, the filter M2 is regenerated, and when the heat treatment is completed, the switching means M7 supplies the cooling fluid M3 that cools the dehumidifier M4 during gas analysis to the filter quantity 2 side. This allows the filter M2 to cool quickly,
Gas analysis can be started early.

[Example] Next, the present invention will be explained in detail. The present invention is not limited to these, but includes various embodiments without departing from the gist thereof.

FIG. 2 shows a configuration diagram of the main parts of a pretreatment device for gas analysis, which is an embodiment of the present invention. This pretreatment device for gas analysis is
A sample gas flow path 3 that guides the sample gas to be measured to the gas analyzer 1 is made of sintered metal, ceramic, etc., and is provided in the middle of the sample gas flow path 3 to filter fine particles such as carbon and oil mist in the sample gas. A heat-resistant porous filter 5 to remove the sample gas, a dehumidifier 7 provided in the middle of the sample gas flow path 3 to condense and remove moisture in the sample gas by cooling it, and suck the sample gas and quantitatively guide it to the analyzer 1 It consists of a pump 9 and its attached devices.

The filter 5 is provided with a heating device 11, and when the filter 5 is regenerated, it is heated with electricity and has the effect of burning or evaporating and removing particulates. A temperature sensor 13 is also provided in contact with this filter to detect the temperature of the filter 5. Further, the differential pressure of the sample gas between the upstream side and the downstream side of the filter 5 is detected by a differential pressure sensor 15.

The dehumidifier 7 is provided with a portex tube 17, compressed air is supplied to the portex tube 17 via a solenoid valve 19, and only cold air is supplied to the dehumidifier 7, while hot air is sent to the outside. It is discharged. The cold air supplied to the dehumidifier 7 comes into contact with the sample gas flow path 3 to exchange heat with the sample gas, bring the sample gas to the dew point, and remove moisture. The condensed water is discharged to the outside from a drain (not shown). Thereafter, the cold air is discharged from the dehumidifier 7 and directly guided to the outside or to the recirculation path 23 via the three-way switching valve 21. This reflux path 23 supplies the cold air to the sample gas flow path 3 between the filter 5 and the dehumidifier 7.

The temperature sensor 13, differential pressure sensor 15, and keyboard 24 for inputting instructions are input to an electronic control circuit 25, and the pump 9, heating device 11, solenoid valve 19, three-way switching valve 21, and LED 27 for warning It is controlled by an electronic control circuit 25.

The electronic control circuit 25 includes a CPU 30, a ROM 31, and a RAM.
32, a backup RAM 33, a clock 34, etc., as a logic operation circuit, and is connected to an input/output port 36 and an output port 37 via a common bus 35 to perform input/output with the outside.

The electronic control circuit 25 includes a buffer 39°40.41 for the detection signals of each of the sensors 13°15 and the keyboard 24 described above.
It has a multiplexer 44 and an A/D converter 45, and these detection signals are input to the CPU 30 via an input/output port 36.

Furthermore, the electronic control circuit 25 controls the pump 9 and the heating device 1.
1. Solenoid valve 19, three-way switching valve 21, and warning LED
27 drive circuit 50. 51. 52.53.54, and the CPL 130 is connected to the drive circuit 50.52 through the output port 55. 51. 52. A control signal is output to 53°54.

Next, the operation control of each of the above components executed by the electronic control circuit 25 will be explained based on the flowchart of FIG. This process consists of a sample gas sampling process, a sampling stop process, and a filter regeneration process.

First, when the process is started, initial settings are made in step 100, and the initial states of various variables and flags are set, and the pump 9, heating device 11, solenoid valve 19, three-way switching valve 21, and warning valve are set. The LED 27 is controlled to the initial state.

Next, in step 110, input from the keyboard 24 is determined. If there is no key human power, the process of step 110 is repeated.

When the key human power is "collection", the sample gas collection process starts. That is, when a measurement is to be performed by the gas analyzer 1, the LF and D27 are controlled to be turned off in step 120, and the solenoid valve 19 is turned on in step 130 to supply compressed air to the portex tube 17. Cooled air is supplied to the dehumidifier 7. Next, in step 140, the pump 9 is turned on and sampling of the sample gas begins.

Next, in step 150, the three-way switching valve 21 is turned on, and the cooling air after absorbing heat in the dehumidifier 7 is discharged to the outside air. In this way, the process returns to step 110 and waits for key human power.

In this manner, the sample gas sampling step is executed, and the gas analyzer 1 is supplied with the sample gas from which particulates and the like have been removed and which has been dehumidified.

When the key input is "stop", the sample gas sampling stop process starts. Step 16 if you perform the key human power to that effect
0 is executed, the solenoid valve 19 is turned off, and the supply of cooling air to the dehumidifier 7 is stopped.

Next, in step 170, the pump 9 is turned off and suction and collection of the sample gas is stopped. Thus step 11 again
Return to 0.

Next, when particulates etc. accumulate on the filter 5 and the differential pressure between the front and rear of the filter 5 becomes large, in step 110, "
When "Regeneration" is key selected, a filter regeneration process is started. First, in step 180, the LED 27 is lit to indicate that the filter regeneration process is in progress.

Next, in step 190, a counter C is set to 1. Next, in step 200, the solenoid valve 19 is turned off, and in step 210, the pump 9 is turned off, and the sample gas suction and collection process and the cooling process of the dehumidifier 7 are stopped. Next, in step 220, the heating device 11 is turned on. At step 230, the detection data of the temperature sensor 13 is determined, and if the temperature of the filter 5 is less than 600°C, the process waits until it reaches 600°C. In this way, the filter 5 is heated and the captured particulates are burned or evaporated.

When the temperature reaches 600°C or higher, it is determined that the heat treatment has been completed,
The heating device 11 is turned off in step 240, the solenoid valve 19 is turned on in step 250, the pump 9 is turned on in step 260, and the three-way switching valve 21 is turned off in step 270. As a result, cooling air passes through the dehumidifier 7, the three-way switching valve 21, and the recirculation path 23 to the filter 5.
and the dehumidifier 7. The above pump 9
The suction amount of the pump 9 is smaller than the supply amount of cooling air, for example, if the suction amount of the pump 9 is 10 to 201/n+in.
The cooling air supply amount is set to 100 to 120.
Since it is set at I2/min, the cooling air flowing into the sample gas flow path 3 from the reflux path 23 branches into the filter 5 side and the dehumidifier 7 side.

The cooling air flowing toward the filter 5 cools the filter 5 rapidly. Moreover, the cooling air flowing to the dehumidifier 7 side cools the dehumidifier 7 in advance. Therefore, even if the temperature of the dehumidifier 7 rises due to the heat from the heating device 11 during the regeneration process, it is cooled in advance, so that it does not adversely affect the dehumidification process, especially at the beginning of the collection process.

Next, in step 280, the output of the temperature sensor 13 is determined, and the above state continues until the temperature of the filter 5 reaches 200° C. or lower, which is a temperature that does not affect the sample gas components. If the temperature is below 200° C., the solenoid valve 19 is turned off in step 290, and the three-way switching valve 21 is turned on in step 300. In this way, the cooling process is completed, and step 31
The output of the differential pressure sensor 15 is determined at 0, and if the differential pressure exceeds the set value, the regeneration of the filter 5 is still insufficient, so the counter C is determined at step 320, and C
If <3, counter C is incremented at step 330. In this way, the process is repeated again from step 200.

The processing of steps 200 to 310 is repeated up to three times depending on the value of counter C. If the differential pressure does not become lower than the predetermined value even after three heat treatments, step 340 is executed after step 320, the LED 27 is blinked, and the pump 9 is turned off in step 350. This gives a warning of an abnormality in the filter 5.

If the filter 5 is recovered by the heat treatment, an affirmative determination is made in step 310, the pump 9 is turned off in step 360, and the LED 27 is turned off in step 370 to notify the end of the heat treatment.

In this way, the process again waits for an instruction at step 110.

With the configuration described above, this embodiment allows the cooled air used in the dehumidifier 7 to be used to cool the filter, and with a simple, low-cost configuration, the heat treatment can be completed extremely quickly. The filter 5 can be cooled to a temperature at which it can be sampled, and gas analysis processing can be performed accurately and efficiently.

In the above embodiment, the cold air supplied from the portex tube 17 corresponds to the cooling fluid M3, and the heating device 11
corresponds to the heating means M5, and the three-way switching valve 21 and the electronic control circuit 25 correspond to the switching means M7. In particular, among the processes of the electronic control circuit 25, the processes of steps 230 to 270 correspond to the processes of the switching means M7.

The present invention has a switching means for supplying the cooling fluid used in the sample gas dehumidifier to the filter after the filter is regenerated by heating the filter, so it has an extremely simple structure and low cost. Nevertheless, the filter can be cooled extremely quickly compared to the conventional method, and gas analysis can be performed accurately and efficiently.

[Brief explanation of the drawing]

FIG. 1 is a block diagram illustrating the basic configuration of a pretreatment device for gas analysis according to the present invention, FIG. 2 is a block diagram illustrating an embodiment of the pretreatment device for gas analysis according to the invention, and FIG. The figure represents a flowchart of the operation process executed by the electronic control circuit. 1... Gas analyzer 3... Sample gas flow path 5... Filter 7... Dehumidifier 9... Pump 11... Heating device 13... Temperature sensor 15... Differential pressure sensor 17...Portex tube 19...Solenoid valve 21...Three-way switching valve 23...Recirculation path 24...Keyboard 2
5...Electronic control circuit 27...LED

Claims (1)

[Scope of Claims] A filter that performs a filtration process on a sample gas, a dehumidifier that dehumidifies the sample gas by heat exchange between a cooling fluid and the sample gas, and a heating means that heats the filter, A gas analysis pretreatment device configured to supply the sample gas processed by the filter and dehumidifier in the sample gas collection process to the gas analyzer, and to heat the filter by the heating means in the filter regeneration process. Further, after filter regeneration processing, switching means is provided for switching the flow path of the cooling fluid discharged from the dehumidifier or the cooling fluid before being supplied to the dehumidifier and supplying the cooling fluid to the filter. A pretreatment device for gas analysis, characterized in that: