JPH0731109B2 - Automatic gas analyzer - Google Patents

Description

TECHNICAL FIELD The present invention relates to an automatic gas analyzer, and in particular to a boiler,
The present invention relates to an automatic gas analyzer suitable for measuring CO ₂ and O ₂ concentrations contained in gas discharged from a combustion device such as a de-easel.

(Prior art) The purpose of measuring CO ₂ and O ₂ concentrations in combustion exhaust gas is an indispensable measurement item for efficiency calculation of boilers, diesel engines, etc. and nitrogen oxide concentration conversion. As a gas analysis method for this purpose, an electric measurement method using magnetism, zirconia, non-dispersive infrared rays, or an Orsatto type gas analyzer is used, but the electric measurement method measures only CO ₂ or O _2. Since it is not possible and the electrical measurement method needs to be calibrated with an Orsatto type gas analyzer, an Orsatt type gas analyzer is often used.

However, in order to collect the sample gas into the gas buret in the Olsat type gas analyzer, the level of the sealing liquid should be adjusted to the 0 scale of the gas buret or when the gas remaining in the absorption jar is transferred to the gas buret. The work of adjusting the liquid level of the absorption liquid to is important for accurately performing gas analysis, but it is a complicated work and causes a long analysis time. In addition, the 0 scale part of the gas buret and the marked part of the absorption bottle are connected with a thin tube for accurate measurement, and the sealing liquid and absorption liquid must be washed out with a little carelessness, and the analyzer must be washed. I also made a mistake.

(Means to be Solved by the Invention) The present invention solves the drawbacks of the conventional gas analyzer, has means for surely performing gas absorption / discharge and gas calibration, and measures the liquid level of the absorbing liquid in the gas absorption chamber. It has a detection means that can perform the operation of matching the lines without error, and can automatically execute each analysis step based on the output signal of each detection means.
The present invention aims to provide an automatic gas analyzer which makes it possible to directly obtain the final gas concentration value.

(Means for Solving Problems) According to the present invention, a sample gas conduit is provided with a first electromagnetic valve, a water content trap for storing water, and a feed mechanism driven by a stepping motor and a piston interlocked therewith. A measuring device having a measuring pipe that changes the inner volume to detect the gas amount and sucks and discharges the gas is sequentially connected by a conduit,
A plurality of gas absorption devices respectively containing different absorption liquids corresponding to sample gas components are connected in parallel to the conduit between the trap and the measuring device via second and third electromagnetic valves, respectively. The gas absorption device is composed of a gas absorption chamber and a buffer chamber that communicate with each other below the partition wall, and a part of the conduit that directly communicates with the gas absorption chamber is a thin tube, and a liquid level gauge with electrodes arranged on the thin tube is attached. And a liquid level gauge above the gas absorption chamber, and a micro switch for detecting the upper limit position and the lower limit position of the piston of the measuring pipe, the detection output signal of the micro switch, and the two liquid levels. A control device with a built-in timer for controlling the opening and closing of the first to third solenoid valves and the driving of the stepping motor by inputting the detection output signal of the meter and the signal of the rotation speed of the stepping motor, and the rotation of the stepping motor. An automatic gas analyzer, characterized in that a device for detecting and storing and calculating the amount of gas sucked into the measuring tube by a few.

EXAMPLES The present invention will be described below with reference to the drawings.

FIG. 1 shows the flow of one embodiment of the automatic gas analyzer according to the present invention. The flow path 1 is a tube made of a material (for example, Teflon under the trade name) that absorbs little gas
5 , the absorbers 3 , 4, and the solenoid valve 1a are all connected by a main pipe. The sample gas passes through the solenoid valve 1a whose valve portion is made of a material having corrosion resistance. The solenoid valve 1a opens when energized and closes when energized. Less than,
The solenoid valves 1b, 1c, 1d used in this flow path also operate in the same manner.

Next, the sample gas passes through the glass trap tube 2 in which water is stored in order to adjust the water concentration contained in the sample gas to be constant. After the trap tube 2, the measuring tube of the suction / discharge section 5
Enter 5a.

The measuring pipe 5a is in the shape of an injection cylinder, and the outer cylinder and the inner cylinder are subjected to a highly airtight process, and have an internal volume of about 10 to 100 ml. A feed mechanism 5b in which a spiral groove that moves with the rotation of the stepping motor 6a of the detector 6 is machined is connected to the inner cylinder of the measuring pipe 5a. The feed mechanism 5b can be driven by applying pulses to the stepping motor 6a, and the stepping motor 6a itself can electrically count the applied pulses. For this reason, the measuring pipe is indirectly measured from the rotation speed of the stepping motor 6a.
The internal volume of 5a can be detected.

The microswitches 5c, 5d, 5e are normal ON-OFF switches with a small cover.The microswitch 5c is located at the upper drive limit of the feed mechanism 5b, and the microswitch 5e is located at the lower drive limit of the feed mechanism 5b. This is a function of limiting the drive range of the feeding mechanism 5b. Further, the micro switch 5d is arranged at the top dead center of the inner cylinder of the measuring pipe 5a, that is, at the reference position. The start position and the stepping motor in the operation of the suction / discharge portion 5 and the operation of the absorbing portions 3 , 4 are set.
Used as the zero rotation position of 6a. The sample gas from the measuring pipe 5a is discharged from the solenoid valve 1e.

A fixed amount of sample gas measured by the measuring pipe 5a is applied to the solenoid valve 1
Absorption containers 3d, 4d introduced into the absorbers 3 , 4 through b, 1c
Is made of a transparent material and consists of an outer cylinder and an inner cylinder. A recess for placing the rotors 3f, 4f is provided at the bottom of the inner cylinder to prevent eccentricity of the rotors 3f, 4f. A cylinder having an inner diameter larger than the outer diameter of the recess of the bottom of the inner cylinder is attached to the inside of the upper part of the outer cylinder, and the outer cylinder and the inner cylinder can be brought into close contact with and removed from each other by a joint surface that is processed to have airtightness. An absorption chamber is formed inside the inner cylinder of each of the absorption containers 3d and 4d, and an annular portion between the outer cylinder and the inner cylinder forms a buffer chamber, and both chambers communicate with each other below the inner cylinder.
The absorption containers 3d and 4d are mounted on the rotators 3g and 4g. Rotator 3
Magnets are attached to the small motors inside g and 4g, and by rotating, the external rotors 3f and 4f are rotated.

The absorption container 3d contains a potassium hydroxide aqueous solution 3e for absorbing CO ₂ gas, and the absorption container 4d contains a mixed aqueous solution 4e of potassium hydroxide and pyrogallol for absorbing O ₂ gas. There is.

Aqueous potassium hydroxide solution 3e is placed on top of the outer cylinders of the absorption containers 3d and 4d.
Also, a platinum wire for detecting the liquid surface of the mixed aqueous solution 4e is embedded. The platinum wires 3c and 4c are arranged as reference electrodes in the absorption chamber, and the platinum wires 3a and 4a are arranged above the absorption chamber for the absorption liquid level detection in the first stage.
In order to detect the absorption liquid level at the final stage, it is placed in a thin tube connected to the absorption chamber, and the reference electrode platinum wires 3c and 4c and the liquid level gauge platinum wires 3a and 4a or platinum wire 3b. The liquid level is measured by detecting the presence or absence of electrical conduction with the 4b. The temperature controller 7 is for adjusting the temperature inside the flow path to an arbitrary temperature, and has a structure in which a uniform temperature is maintained by a circulation fan. Control device 8
Is a sequence control in the flow path, the main control range is the introduction of the sample gas, the measurement of the sample gas, the opening and closing of the solenoid valve, etc., the sample gas amount of the measuring pipe 5a step 6 log mode 6a After being counted as the number of pulses from the
Is printed and recorded on.

Next, the measurement procedure will be described below.

1) Open the solenoid valve 1d, rotate the stepping motor 6a, move the feeding mechanism 5b to the position of the micro switch 5c, and then close the solenoid valve 1d.

2) Open the solenoid valves 1b, 1c, rotate the stepping motor 6a again, and pull down the piston to reduce the pressure above the absorption vessels 3d, 4d, and by avoiding the pressure between the absorption chambers and the buffer chambers, the absorption vessels 3d, 4d. Potassium hydroxide aqueous solution 3e and mixed aqueous solution 4 in
The liquid level of e is rapidly raised to the platinum wires 3a and 4a, and then gradually raised to the positions of the platinum wires 3b and 4b. After that, solenoid valves 1b and 1c
Close. Open solenoid valve 1d again, stepping motor 6a
Is rotated, the measuring pipe 5a is moved to the position of the micro switch 5c, the piston is pushed up to the top, the gas in the measuring pipe is discharged, and then the solenoid valve 1d is closed.

With the above operation, the measurement preparation is completed.

3) The sample gas to be analyzed is supplied from the channel 1.

4) Open the solenoid valve 1a, rotate the stepping motor 6a to pull down the piston, and suck the sample gas into the measuring pipe 5a.
After closing the solenoid valve 1a, the solenoid valve 1d is opened, the stepping motor 6a is rotated to push up the piston, and the sample gas in the measuring pipe 5a is discharged.

5) The operation of item 4) is repeated 2-3 times to replace the inside of the measuring pipe 5a with the sample gas.

6) Open the solenoid valve 1a, drive the stepping motor 6a to pull down the measuring pipe 5a, suck the sample gas, collect the sample gas, and then close the solenoid valve 1a.

7) In order to equilibrate the flow path between the solenoid valve 1a and the solenoid valve 1d with atmospheric pressure, the solenoid valve 1d is opened for a certain time and then closed again. During this period, the flow path is open to the atmosphere via the solenoid valve 1d, but the gas does not flow in the front flow path, and the diffusion rate in the flow path is extremely slow, so that impurities in the atmosphere are There is no risk of mixing in the measuring tube and mixing in the sample gas.

8) The solenoid valve 1b is opened, the sample gas in the measuring pipe 5a is driven by the stepping motor 6a to be sent to the absorption container 3d, and then the solenoid valve 1b is closed again.

9) When the sample gas is introduced into the absorption container 3d, at the same time, the rotor 3f in the absorption container 3d is rotated by the rotator 3g, and the sample gas and the potassium hydroxide aqueous solution 3e are agitated and brought into contact with each other to reduce CO ₂ in the sample gas. Is absorbed.

10) After a certain period of time, open the solenoid valve 1b, stepping motor
6a is driven to transfer the unabsorbed gas in the absorption container 3d to the measuring pipe 5a until the liquid surface of the potassium hydroxide aqueous solution 3e reaches the platinum wire 3b.

11) The rotation speed of the stepping motor 6a in the item 10) is stored in the control device 8 as the measured rotation speed.

12) The control device 8 uses the memory value of the reference number of revolutions of the stepping motor 6a, calculates the measurement result by the following equation, and prints the concentration (%) of CO _{2 in} the sample gas on the printer 9.

CO ₂ (%) = measured rotation speed / reference rotation speed × 100 13) Perform the same operation as described in 8) to 11) for the unabsorbed gas remaining in the measuring pipe 5a again in the system of the solenoid valve 1c and the absorption container 4d. The concentration (%) of O ₂ in the sample gas is repeatedly printed on the printer 9.

O ₂ (%) = measured rotation speed / reference rotation speed × 100 14) After the completion of the first measurement, the control device 8 returns to the state of the item 3) and is reset for the next measurement preparation.

Table 1 is a comparison of the measurement results by the device of the present invention (value of X) and the Orsatto gas analyzer (value of Y) when targeting combustion exhaust gas, and CO ₂ and O ₂ are both 0.1 to 0.2. %, And the correlation coefficient (r) showing the relationship between the two shows that the device of the present invention has a very strong relationship with the Olsat type gas analyzer.

(Advantages of the Invention) The present invention, by adopting the above configuration, has succeeded in completely automating a gas analyzer, and in particular, a gas for detecting a reference line of a microswitch and a gas absorbing device for detecting a piston position of a measuring pipe. By measuring the liquid level gauge of the absorbing liquid in the first stage of the absorption chamber and the liquid level gauge in the narrow tube of the final stage, it is possible to perform reliable and quick control without malfunction in gas calibration, and to control the solenoid valve and stepping. The operation of the motor was made smooth and the entire automation could be performed. Further, since the detection signal of the gas amount is also the pulse signal of the stepping motor, an accurate value can be detected without providing any special detection means, and the subsequent arithmetic processing becomes extremely easy.

In addition, by disposing a plurality of gas absorption devices corresponding to sample gas components in parallel in one metering device, the trap can be compared with the case where a plurality of automatic gas analyzers are used together for the analysis of multiple components. Not only is it possible to use the weighing device and the weighing device, but the calibration of those devices is simplified and the analytical operation is made extremely easy.

[Brief description of drawings]

FIG. 1 is an explanatory view showing the flow of an automatic gas analyzer showing one embodiment of the present invention.

Claims (1)

[Claims] 1. A sample gas conduit is provided with a first solenoid valve, a water content-adjusting trap for storing water, and a feed mechanism driven by a stepping motor and a piston linked with the feed mechanism to change the inner volume to change the gas amount. A plurality of measuring devices, each of which has a measuring pipe for detecting and sucking and discharging gas, are sequentially connected by a conduit, and a plurality of absorbing liquids corresponding to sample gas components are respectively accommodated in the conduit between the trap and the measuring device. Gas absorbers of the above are connected in parallel via second and third electromagnetic valves, respectively, and the gas absorbers are composed of a gas absorption chamber and a buffer chamber that communicate with each other below the partition wall, and directly communicate with the gas absorption chamber. Part of the conduit to be a thin tube, a liquid level gauge with an electrode is attached to the thin tube, and a liquid level gauge above the gas absorption chamber, the upper limit position and the lower limit position of the piston of the measuring pipe. Detect A micro switch is additionally provided, and a detection output signal of the micro switch, a detection output signal of the two liquid level gauges, and a signal of the number of revolutions of the stepping motor are input, and opening / closing of the first to third solenoid valves and of the stepping motor. An automatic gas analyzer, which is provided with a control device with a built-in timer for controlling the drive and a device for detecting, storing, and calculating the amount of gas sucked into the measuring pipe by the rotation speed of a stepping motor.