JPS6082849A - Oxygen concentration measuring apparatus - Google Patents

Abstract

PURPOSE:To enhance measurement accuracy in low cost, by fixing a solid electrolyte in the vicinity of the leading end of a cylinder having piercing holes provided to the wall thereof an forming a negative pressure part in the cylinder provided in the stream of measuring gas while exhausting the gas in the cylinder through the piercing hole. CONSTITUTION:A test tube shaped zirconia element 20 is fixed to the leading end of a cylinder having piercing holes 21 provided to the wall thereof. The element 20 is provided in the stream of measuring gas from the lateral side and the interior thereof is filled with comparative gas from a comparative gas supply means 24. The signal corresponding to the difference between the oxygen concns. of the measuring gas and the comparative gas is outputted through electrodes 7, 8. A signal processing part inputs this signal and the signal of a thermocouple 25 and an oxygen concn. signal is outputted by predetermined operation processing. A negative pressure region is formed in a holding part 23 by the stream of the measuring gas in the outside of the holding part 2 and the gas flowing into this negative pressure region is exhausted to the outside from the piercing hole 21 and, because the comparative gas is not leaked to the side of the measuring electrode 7 and no measuring gas is leaked to the side of a comparison electrode 8, measuring accuracy is enhanced.

Description

Detailed description of the invention [Technical field to which the invention pertains] The present invention fixes a fixed electrolyte at or near the tip of a cylindrical body having a through hole in its wall, and controls the flow of a measurement gas through the fixed electrolyte and the through hole. The present invention relates to an oxygen concentration measuring device that is installed inside a cylinder to form a negative pressure region within the cylinder, and discharges gas inside the cylinder to the outside through a through hole.

[Conventional technology]

2. Description of the Related Art Conventionally, as an oxygen concentration measuring device equipped with a solid electrolyte, there are devices shown in FIGS. 1 and 2, for example. In FIG. 1, the oxygen J degree measuring device has a cylindrical body 2 that fixes a base 1 to the tip, a metal flange 4 that is integrated with an inorganic adhesive 3, and this flange 4 is connected to a metal O ring 5. A signal is inputted through a test tube-shaped zirconia element 6 which is bolted to the base 1 of the cylindrical body through the zirconia element 6, and electrodes 7 and 8 which are fixed to both sides of the end wall of the zirconia element 6, and predetermined processing is performed. It has a signal processing section (not shown) that outputs an oxygen part signal, and a temperature control section (not shown) that controls the zirconia element 5 at a temperature of approximately 700 t. When the zirconia element 6 is inserted and installed, a comparison gas (air) is introduced into the zirconia element 6 (electrode 8 side) from inside the cylinder 2.

On the other hand, the oxygen concentration measuring device shown in FIG. 2 includes a test tube-shaped zirconia element 12 having a threaded portion 11 that is integrated with an O-ring 10 (organic sealing material) interposed therebetween, and a signal processing section similar to that shown in FIG. and a temperature control section (none of which are shown), the tip of the zirconia element 12 is inserted into the furnace, and an organic sealing material is interposed in the mounting opening 14 provided in the furnace wall 13, and the threaded part 11 is inserted into the furnace wall 13. are screwed together and fixed, and a comparison gas (air) is flowed into the inside of the zirconia element 12 (on the electrode 8 side).

In addition, generally 1 zirconia element 12 is 0 ring 10 (
In order to keep the temperature at the location where the organic seal is installed below the operating temperature limit of the 01J ring 10, its body is long.

In the above configuration, the zirconia elements 6 and 12 generate a signal corresponding to the difference in oxygen concentration between the comparison gas and the measurement gas at a temperature of about yaoc and with the comparison gas and the measurement gas isolated by the zirconia element or the like. Output via electrodes 7 and 8. Then, the signal processing section inputs this signal, performs a certain calculation, and outputs an oxygen concentration signal.

However, in the conventional device shown in FIG. 1, when the temperature of the zirconia element 6 exceeds 700C, the adhesive 3 cracks or breaks due to the difference in thermal expansion between the zirconia element 6 and the flange 4. There is a risk of leakage to the side, resulting in a decrease in measurement accuracy. Further, in the conventional device shown in FIG. 2, the zirconia element 12 has a long structure, which causes a problem of high cost.

[Purpose of the invention]

The present invention has been made in view of this point, and an object thereof is to provide an oxygen concentration measuring device with improved measurement accuracy without increasing costs.

[Structure of the invention]

The oxygen concentration measuring device of the present invention, which has achieved the above object, is an oxygen concentration measuring device equipped with a solid electrolyte that blocks two types of gases having different oxygen concentrations. a solid electrolyte holding portion having a through hole in a wall on a rear end side of the cylinder body from the fixed position of the solid electrolyte, and means for continuously supplying a comparison gas to the solid electrolyte near the inner wall of the cylinder body. When the solid electrolyte holding part is installed with the through hole in the flow of the measurement gas, a negative pressure region is created in the cylinder and the gas in the cylinder is discharged from the through hole to the outside of the cylinder. configured to form.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 3 is a diagram showing an embodiment of the present invention.

The oxygen concentration measuring device is a cylindrical body with a test tube-shaped zirconia element 20 fixed at its tip, and a through hole 21 (a filter 22 a zirconia element holding section 23 having a zirconia element holding section 23 (wherein a zirconia element is installed), a means 24 for continuously supplying a reference gas near the inner wall of the cylindrical body of the zirconia element 20, and electrodes 7 and 8 fixed to both sides of the tip wall of the zirconia element 20. Through
A signal processing section (Fig. (not shown). The tip of the holding part 23 is the base 26 that serves as the installation base for the zirconia element 20.
The base 26 includes a substantially cylindrical cap 27 on which the zirconia element 10 is installed and fixed. base 2
6 is a through hole 28 through which the comparison gas supply means 24 is inserted;
It has a through hole z9 through which the thermocouple 25 is inserted, a through hole 31 connected to the calibration gas supply pipe 30, and a through hole 52 through which the inside and outside of the base 26 are communicated. My father, 27 years old at camp.
A large through hole formed on the bottom and a through hole 34 formed on the side wall.
and 35, the zirconia element 20 is fixed to the base 26 with knockings 36 and 37 interposed, and is integrated with the cylinder body 23. This integration means that the tip of the comparison gas supply means z4 is This is done by inserting it into the element 20 and connecting the through holes 29 and 34 and the through holes 31 and 35, respectively.In this configuration, the through hole 32 is inserted into the outside of the zirconia element 20 (in contact with the measurement gas 1llil to do
) and the cylindrical body 23.

The above zirconia element 20I'i, holding part (cylindrical body) 230
The through hole 21 is positioned in the flow of the measurement gas at 600 to +001:F, and the holding part 26 (flange if integrated with the flange) is fixed to the receiving port #5@.

In the above configuration, the zirconia element 20 is in the flow of the measurement gas in the direction of the arrow X shown in FIG. It is filled with a comparison gas from the comparison gas supply means 24. Then, a signal corresponding to the oxygen concentration difference between the measurement gas and the comparison gas, that is, a signal based on the Nernst equation, is outputted via the electrodes 7 and 8. The signal processing section inputs this signal and the signal from the thermocouple 25, performs predetermined calculations, and outputs an oxygen concentration signal.

On the other hand, since the flow of the measurement gas flowing outside the holding part 23 entrains the gas near the through hole 21, a negative pressure region is formed inside the holding part 23 according to Bernoulli's law. According to experiments by the present inventors, measurement point P1 shown in FIG.
and the pressures P1 and P2 at P2 and the flow rate V of the measurement gas
The results of the relationship are shown in Figure 5. Therefore, the gas flowing toward this negative pressure area is transferred from the through hole 21 to the holding part 2.
It is discharged as an outward flow of 3. That is, the comparison gas in the zirconia element 20 flows to the pressure measurement point P1 and is discharged from the through hole 21, and the measurement gas at the pressure measurement point P2 flows through the through holes 32 and 34 (29). It becomes a flow to the pressure measurement point P1 and is completely discharged from the through hole 21. Therefore, the comparison gas will not leak to the measurement electrode 7 side, and the measurement gas will not leak to the comparison electrode 8 side.

Note that the present invention is not limited to the upper mounting N'r example, and the number of through holes 21 in the holding part may be increased or decreased, and the filter 22d may be installed as necessary. good. Alternatively, the zirconia element 20 may be fixed by being inserted slightly into the tip of the holding portion (moved to the rear end side). Furthermore, the zirconia element may be replaced with a 1114 isoelectrolyte.

〔Effect of the invention〕

As explained above, according to the oxygen concentration measuring device of the present invention, a solid electrolyte is identified at or near the tip of a cylindrical body (holding part) having a through hole in the wall, and the solid electrolyte and the through hole are connected to the measuring gas. Because it is installed in a flow to create a negative pressure region inside the cylinder, and the gas inside the cylinder is discharged to the outside through a through hole, it can be used regardless of the length or shape of the solid electrolyte.
Furthermore, it is possible to prevent the ratio from leaking to the comparison electrode side. Therefore, measurement accuracy can be improved without increasing costs.

[Brief explanation of drawings]

1 and 2 are diagrams showing a conventional example, FIG. 3 is a diagram showing an embodiment of the present invention, FIG. 4 is a diagram showing the flow of measurement gas, and FIG. 5 is a diagram showing a holding section. FIG. 3 is a diagram showing the relationship between the pressure inside the cylinder (cylindrical body) and the flow rate of the measurement gas. 7... Measuring electrode, 8... Reference electrode, 2o... Zirconia element, 21... Through hole provided in the wall of the cylinder, 25...
...Holding part (cylindrical body), 24...Comparison gas supply means, 2
6...Base, 27...Gap, 28.29.3+
, 32 , 53 , 54 , 35 ... through hole, 36
．． 57-...basoki/gu. Figure 1 i, -t iu

Claims (1)

[Claims] In an oxygen concentration measuring device equipped with a solid electrolyte that blocks two gases with different oxygen concentrations, the solid electrolyte is fixed at or near the tip of the cylinder, and the solid electrolyte is fixed at the tip of the cylinder. A solid electrolyte holding part having a through hole in a wall on the rear end side, and a means for continuously supplying a comparison gas to the vicinity of the inner wall of the cylinder of the solid electrolyte, the through hole being included in the flow of the measurement gas. An oxygen concentration measuring device characterized in that, when the solid electrolyte holding part is installed, a negative pressure region is created within the cylinder and a flow is formed to discharge gas within the cylinder to the outside of the cylinder through the through hole.