JP2015059848A - Magnetic oxygen analyzer, and sensor unit for magnetic oxygen analyzer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic oxygen analyzer capable of measuring oxygen concentration in gas to be measured at high sensitivity while a manufacturing cost is reduced.SOLUTION: A flow rate sensor 21 arranged in a bypass flow passage communicated with an auxiliary gas flow passage of a magnetic oxygen analyzer comprises: a substrate 21; a sensor element 24 and bridge resistances 25a, 25b mounted on the substrate; wiring patterns 27 to 30 formed on the substrate; bonding pads 27a to 30a provided for end parts of the wiring patterns; and lead wires 31a to 31d connected between the sensor element 24 and the bonding pads 27a to 30a by using a wire bonding machine.

Description

  The present invention relates to a magnetic oxygen analyzer and a sensor unit for a magnetic oxygen analyzer.

The measurement principle of the magnetic oxygen analyzer will be described with reference to FIGS. 4A to 4C (see, for example, Patent Document 1).
FIG. 4A shows the relationship between oxygen molecules and a magnetic field when a means (magnet) for generating a magnetic field is arranged in a gas containing oxygen. As shown in FIG. 4B, a force that attracts oxygen acts on a portion where the magnetic field is strong and the strength changes (the end of the magnetic pole that is a non-uniform magnetic field), and the end of the magnetic pole The right force and the left force are pressed against each other and balanced, and oxygen molecules are attracted by the influence of the magnetic field and move into the magnetic field (magnet gap). As a result, as shown in FIG. 4C, the pressure (concentration) of the attracted oxygen is higher in the magnetic field than in the magnetic field.

  As a magnetic oxygen analyzer employing the above-described measurement principle, apparatuses shown in FIGS. 5 to 7 are known. As shown in FIG. 5, the magnetic oxygen analyzer includes a sample cell 1 having a flow path for flowing a measurement gas, and a detection circuit 2 for detecting the oxygen concentration contained in the measurement gas. . The detection circuit 2 detects the oxygen concentration in the measurement gas based on a signal from the flow rate sensor 12 configured by a heat ray sensor installed in the sample cell 1.

  The sample cell 1 includes a sample channel 3 having a rectangular cross section, a measurement gas inlet 4 provided in communication with one end of the sample channel 3 in the axial direction, and the other end in the axial direction of the sample channel 3 A measurement gas outlet port 5 provided in communication with the sample gas passage and a sample channel 3 on the side of the measurement gas outlet port 5 and provided opposite to each other in a radial direction perpendicular to the axial direction of the sample channel 3. The auxiliary gas flowing into the first auxiliary gas inlet 6 and the second auxiliary gas inlet 7 and the auxiliary gas supply channel 8 is transferred from the first auxiliary gas inlet 6 and the second auxiliary gas inlet 7 to the sample channel 3. A pole piece that forms a region of the magnetic field Mf in the vicinity of the first auxiliary gas branch channel 9 and the second auxiliary gas branch channel 10 supplied at the same flow rate and the first auxiliary gas inlet 6 of the sample channel 3 communicate with each other. (Not shown), the first auxiliary gas branch channel 9 and the second auxiliary gas branch It includes a bypass passage 11 communicating with the road 10, the.

Further, a flow rate sensor 12 is disposed at an intermediate position of the bypass flow path 11, and the detection circuit 2 is connected to the flow rate sensor 12. The detection circuit 2 detects the oxygen concentration contained in the measurement gas by receiving and amplifying the signal from the flow sensor 12.
As shown in FIG. 6, the flow sensor 12 includes a sensor element 13, a sensor mounting block 14 that places the sensor element 13 in the bypass flow path 11, and a plurality of hermetic terminals 15 a that connect the sensor element 13 to the detection circuit 2. To 15c.
The sensor element 13 is a member in which a heater part and a sensor part (not shown) are built and a gas passage hole 13a is formed. The sensor mounting block 14 includes a main body fixing portion 14b in which a gas passage hole 14a is formed. The sensor element 13 is fixed to the main body fixing portion 14b of the sensor mounting block 14 with an adhesive such as epoxy resin so that the gas passage holes 13a and 14a correspond to each other.

Further, end portions of hermetic terminals 15a to 15c supported by the sensor mounting block 14 extend in the vicinity of the sensor element 13 fixed to the main body fixing portion 14a, and lead wires 16a to 16b taken out from the sensor element 13 are extended. 16c is wound around the ends of the hermetic terminals 15a to 15c and is electrically connected by soldering.
As shown in FIG. 7, the flow sensor 12 is arranged in a gas pipe 17 that constitutes the bypass flow path 11 so that the auxiliary gas flowing through the bypass flow path 11 passes through the gas passage hole 13 a of the sensor element 13. Designed.

FIG. 3 of JP2004-325098A

By the way, in the flow sensor 12 constituting the magnetic oxygen analyzer, the lead wires 16a to 16c taken out from the sensor element 13 are connected to the end portions of the hermetic terminals 15a to 15c by soldering. When the applied flux scatters and adheres to the sensor element 13 in the process of melting the solder, and the sensor element 13 changes with time, the flow sensor 12 may not output a stable detection signal.
In addition, the process of winding the lead wires 16a to 16c around the ends of the hermetic terminals 15a to 15c is a fine work, and is a process that depends on a worker with a special skill. .
The present invention has been made in view of the above circumstances, and a magnetic oxygen analyzer and a sensor for a magnetic oxygen analyzer capable of measuring oxygen concentration in a measurement gas with high sensitivity while reducing the manufacturing cost. The purpose is to provide units.

  In order to achieve the above object, a magnetic oxygen analyzer according to one aspect of the present invention includes a sample flow path, a measurement gas inlet and a measurement gas outlet formed at both ends of the sample flow path, and the measurement gas outlet. A first auxiliary gas inlet and a second auxiliary gas inlet provided opposite to each other on the side of the sample flow path, an auxiliary gas flow path connected to the first and second auxiliary gas inlets, A bypass passage communicating the auxiliary gas passage on the first auxiliary gas inlet side and the auxiliary gas passage on the second auxiliary gas inlet side, and a flow rate sensor disposed in the bypass passage. The flow rate sensor detects a change in the flow rate of the bypass channel caused by supplying the auxiliary gas from an intermediate position of the auxiliary gas channel and applying a magnetic field to the sample channel near the first auxiliary gas inlet. By detecting In the magnetic oxygen analyzer for calculating the oxygen concentration contained in the measurement gas, the flow sensor includes a substrate, a sensor element and a bridge resistor mounted on the substrate, and a wiring pattern formed on the substrate. The structure includes a bonding pad provided at an end of the wiring pattern and a lead wire connected between the sensor element and the bonding pad using a wire bonding machine.

  According to the magnetic oxygen analyzer according to one aspect of the present invention, the flow rate sensor is stable because there is no possibility that the sensor element will change over time as compared with a conventional flow rate sensor that connects lead wires by soldering work. A detection signal can be output. In addition, since there are almost no steps depending on the skill of the operator when assembling the flow sensor of the present invention, the manufacturing cost can be reduced.

  A sensor unit for a magnetic oxygen analyzer according to one aspect of the present invention is a unit including the flow sensor of the magnetic oxygen analyzer described above, and is located in the middle of the bypass flow path and the bypass flow path. A flow rate sensor in the middle of the bypass flow path by disposing the flow rate sensor in the sensor placement space from the opening. Is a sensor unit for a magnetic oxygen analyzer.

Furthermore, in the sensor unit for a magnetic oxygen analyzer according to one aspect of the present invention, the flow sensor arranged in the sensor arrangement space is integrated with the substrate while the substrate is fixed to the bottom of the sensor arrangement space. It is preferable that the closed blocking member closes the opening of the block body in which the sensor arrangement space is formed.
According to the sensor unit for a magnetic oxygen analyzer according to one aspect of the present invention, the magnetic oxygen analyzer can be easily assembled by connecting to another unit constituting the magnetic oxygen analyzer.

According to the magnetic oxygen analyzer of the present invention, the flow sensor that outputs a stable detection signal is provided, and since there are almost no processes depending on the skill of the operator when the flow sensor is assembled, the manufacturing cost is reduced. Thus, it is possible to provide a magnetic oxygen analyzer that can measure the oxygen concentration in the measurement gas with high sensitivity.
In addition, according to the sensor unit for a magnetic oxygen analyzer according to the present invention, the assembly efficiency of the magnetic oxygen analyzer is greatly increased by connecting this sensor unit to another unit constituting the magnetic oxygen analyzer. Can be improved.

It is a figure which shows the sensor unit for magnetic oxygen analyzers of one Embodiment which concerns on this invention. It is a figure showing a flow sensor of one embodiment concerning the present invention. It is the figure which decomposed | disassembled the flow sensor of one Embodiment which concerns on this invention. It is a figure which shows the measurement principle of a magnetic oxygen analyzer. It is a schematic block diagram which shows a magnetic oxygen analyzer. It is a figure which shows the conventional flow sensor. It is the figure which has arrange | positioned the conventional flow sensor in the bypass flow path of a magnetic oxygen analyzer.

DESCRIPTION OF EMBODIMENTS Hereinafter, modes for carrying out the present invention (hereinafter referred to as embodiments) will be described in detail with reference to the drawings. The same components as those of the magnetic oxygen analyzer shown in FIG.
FIG. 1 shows a sensor unit SU according to the present invention. This sensor unit SU shows the block body 20 which forms the bypass flow path 11 (refer FIG. 5), and the flow sensor 21 with which the block body 20 was mounted | worn so that it might be arrange | positioned in the middle of the bypass flow path 11. Is. The sensor unit SU is connected to another unit (not shown) that forms the first auxiliary gas branch flow path 9 and the second auxiliary gas branch flow path 10 shown in FIG. Configure.

The block body 20 constituting the sensor unit SU is formed with a sensor arrangement space 22 that communicates in the middle of the bypass flow path 11 and opens to the outside, and the flow rate sensor 21 is mounted in the sensor arrangement space 22.
The flow sensor 21 of this embodiment is a heat ray sensor, and as shown in FIG. 2, a substrate 23 made of glass epoxy or ceramic, a sensor element 24 and bridge resistors 25a and 25b mounted on the substrate 23, and a sensor And a fixing ring 26 for holding the substrate 23 arranged in the arrangement space 22 on the block body 20.

The substrate 23 has a rectangular plate shape, and a gas passage hole 23a is formed on one end side in the longitudinal direction. A heater part and a sensor part (not shown) are built in one end of the substrate 23 in the longitudinal direction, and the sensor element 24 having the gas passage holes 24a is mounted in a state where the gas passage holes 23a and 24a are made to correspond to each other. Has been. Bridge resistors 25 a and 25 b are mounted on the other end side of the substrate 23 in the longitudinal direction.
On the substrate 24, a plurality of wiring patterns 27-30 are formed along the longitudinal direction, and bonding pads 27a, 27b-30a, 30b are formed at both ends of the wiring patterns 27-30.

The sensor element 24 and bonding pads 27a, 28a, 29a, 30a on one end side of the plurality of wiring patterns 27-30 are electrically connected via a plurality of lead wires 31a-31d. Connection work of the lead wires 31a to 31d is performed by a wire bonding machine.
And the lead wire (not shown) connected with the detection circuit 2 (refer FIG. 5) is electrically connected to bonding pad 27b, 28b, 29b, 30a of the other end side of the wiring patterns 27-30.

As shown in FIG. 3B, the fixing ring 26 has a circular outer peripheral shape that is the same shape as the opening peripheral edge of the sensor arrangement space 22 of the block body 20, and the substrate 24 is on the other end side in the longitudinal direction. An engagement slit 26a that can be fitted in is formed.
Then, the substrate 24 on which only the bridge resistors 25a and 25b are not mounted is fitted into the engagement slit 26a of the fixing ring 26 from the other end side, and the fixing ring 26 is moved across the wiring patterns 27 to 30 to the substrate 24. Lock to. Thereafter, the flow rate sensor 21 is formed by mounting the bridge resistors 25 a and 25 b on the substrate 24.

  The flow sensor 21 having the above-described configuration is mounted in the sensor arrangement space 22 of the block body 20, the substrate 24 that contacts the bottom of the sensor arrangement space 22 is bonded with an epoxy resin adhesive, and the opening of the sensor arrangement space 22 is fixed to the fixing ring. 26, the flow rate sensor 21 is arranged in the middle of the bypass flow path 11, and the sensor unit SU in which the auxiliary gas flowing through the bypass flow path 11 passes through the gas passage hole 24a of the sensor element 24 is assembled.

The operation of the magnetic oxygen analyzer equipped with the flow sensor 21 of the present embodiment will be described with reference to FIGS. 1 to 3 and FIG. In the following description, the flow sensor 12 of FIG. 5 is replaced with the flow sensor 21 of the present embodiment.
The measurement gas introduced from the measurement gas inlet 4 of the sample cell 1 flows toward the measurement gas outlet 5. In addition, the auxiliary gas supplied from the auxiliary gas supply flow path 8 is divided into the first auxiliary gas branch flow path 9 and the second auxiliary gas branch flow path 10, and the first auxiliary gas inlet 6 and the second auxiliary gas flow. It flows into the sample channel 3 from the inlet 7, merges with the measurement gas, and flows to the measurement gas outlet 5. Further, a part of the auxiliary gas that is branched from the auxiliary gas supply flow path 8 to the first auxiliary gas branch flow path 9 and the second auxiliary gas branch flow path 10 is a bypass flow path that is connected to the first auxiliary gas branch flow path 9. 11 flows from the bypass flow path 11 connected to the second auxiliary gas branch flow path 10 toward the flow sensor 21.

  When oxygen molecules are not contained in the measurement gas, a region of the magnetic field Mf is formed in the vicinity of the first auxiliary gas inlet 6 of the sample channel 3 communicating with the measurement gas. The pressure does not increase. Thereby, the fluid resistance when the auxiliary gas flows out from each of the first auxiliary gas branch flow path 9 and the second auxiliary gas branch flow path 10 to the sample flow path 3 becomes the same, and the first auxiliary gas branch flow path 9 Therefore, the flow rate of the auxiliary gas passing through the flow rate sensor 21 in the bypass flow path 11 is the same as the flow rate of the auxiliary gas passing from the second auxiliary gas branch flow path 10 through the flow rate sensor 21 in the bypass flow path 11. Thereby, the signal of the flow sensor 21 is not obtained, and the detection circuit 2 does not detect the oxygen concentration.

  On the other hand, when oxygen molecules are contained in the measurement gas, if a region of the magnetic field Mf is formed in the vicinity of the first auxiliary gas inlet 6 of the sample flow path 3, the oxygen molecules are attracted to that portion, and oxygen The pressure increases due to the cohesive pressure. Therefore, the fluid resistance when the auxiliary gas flows out from the first auxiliary gas branch flow path 9 to the sample flow path 3 increases, and the outflow amount decreases. On the other hand, since no magnetic field is generated in the vicinity of the second auxiliary gas inlet 7 of the sample channel 3 communicating, the fluid resistance does not increase, and the outflow of the auxiliary gas is compared with the first auxiliary gas inlet 6 side. The amount increases.

Thereby, the auxiliary gas is the first auxiliary gas at the point P0 (hereinafter referred to as the branch point P0) where the auxiliary gas supply flow path 8 branches to the first auxiliary gas branch flow path 9 and the second auxiliary gas branch flow path 10. The diversion ratio at the time of branching to the branch flow path 9 and the second auxiliary gas branch flow path 10 changes, and the flow rate of the auxiliary gas from the first auxiliary gas branch flow path 9 through the flow rate sensor 21 in the bypass flow path 11 A difference occurs in the flow rate of the auxiliary gas passing through the flow rate sensor 21 in the bypass flow channel 11 from the second auxiliary gas branch flow channel 10, and the flow rate sensor 21 obtains a signal indicating a change in the flow rate of the auxiliary gas. Detects the oxygen concentration of the measurement gas.
Here, the measurement gas inlet according to the present invention corresponds to the measurement gas inlet 4, the measurement gas outlet according to the present invention corresponds to the measurement gas outlet 5, and the auxiliary gas flow path according to the present invention is the first auxiliary gas. Corresponding to the branch flow path 9 and the second auxiliary gas branch flow path 10, the closing member according to the present invention corresponds to the fixing ring 26 that sandwiches the substrate 24 with its engagement slit 26 a.

Next, the effect of this embodiment is demonstrated.
In the flow sensor 21 of this embodiment, a sensor element 24 mounted on a substrate 23 and bonding pads 27a, 28a, 29a, and 30a provided on end portions of wiring patterns 27 to 30 formed on the substrate 24 are wire bonded. Compared with the conventional flow rate sensor in which the lead wires 31a to 31d are connected using a machine and the lead wires are connected by soldering work, there is no possibility that the sensor element will change with time. The flow sensor 21 can output a stable detection signal. Therefore, it is possible to provide a magnetic oxygen analyzer that measures the oxygen concentration in the measurement gas with high sensitivity.

In addition, in the conventional flow sensor 12 shown in FIGS. 6 and 7, the process of winding the lead wires 16a to 16c around the ends of the hermetic terminals 15a to 15c is a fine work and depends on an operator having a special skill. However, since the flow sensor 21 of the present embodiment has almost no process depending on the skill of the operator when assembling, the manufacturing cost can be reduced.
Therefore, the magnetic oxygen analyzer including the flow sensor 21 having the above-described configuration can measure the oxygen concentration in the measurement gas with high sensitivity while reducing the manufacturing cost.

  Further, the sensor unit SU constituting the magnetic oxygen analyzer of the present embodiment has the flow sensor 21 mounted in the sensor arrangement space 22 of the block body 20, and the substrate 24 that contacts the bottom of the sensor arrangement space 22 is bonded with epoxy resin. A unit in which the flow rate sensor 21 is arranged so that the flow rate of gas flowing through the bypass channel 11 can be detected with high accuracy by adhering with an agent or the like and closing the fixing ring 26 at the opening of the sensor arrangement space 22. A magnetic oxygen analyzer can be easily assembled by connecting to other units constituting the oxygen analyzer.

  DESCRIPTION OF SYMBOLS 1 ... Sample cell, 2 ... Detection circuit, 3 ... Sample flow path, 4 ... Measurement gas inlet, 5 ... Measurement gas outlet, 6 ... 1st auxiliary gas inlet, 7 ... 2nd auxiliary gas inlet, 8 ... Auxiliary gas supply channel, 9 ... first auxiliary gas branch channel, 10 ... second auxiliary gas branch channel, 11 ... bypass channel, 20 ... block body, 21 ... flow sensor, 22 ... sensor arrangement space, 23 ... Substrate, 24 ... sensor element, 25a, 25b ... bridge resistance, 26 ... fixing ring, 26a ... engagement slit, 23a ... gas passage hole, 24a ... gas passage hole, 27-30 ... wiring pattern, 27a, 27b-30a, 30b: Bonding pad, 31a to 31d: Lead wire, SU: Sensor unit

Claims (3)

A sample flow path, a measurement gas inlet and a measurement gas outlet formed at both ends of the sample flow path, and a first auxiliary gas flow inlet and a first gas flow path provided opposite to the sample flow path on the measurement gas outlet side 2 auxiliary gas inlets, auxiliary gas passages connected to the first and second auxiliary gas inlets, the auxiliary gas passages on the first auxiliary gas inlet side, and the second auxiliary gas inlet side A bypass flow path communicating with the auxiliary gas flow path, and a flow rate sensor disposed in the bypass flow path, the auxiliary gas being supplied from an intermediate position of the auxiliary gas flow path, and the first auxiliary gas In a magnetic oxygen analyzer that calculates the oxygen concentration contained in the measurement gas by detecting a change in the flow rate of the bypass flow channel caused by applying a magnetic field to the sample flow channel near the inlet by the flow sensor. ,
The flow sensor uses a substrate, a sensor element and a bridge resistor mounted on the substrate, a wiring pattern formed on the substrate, a bonding pad provided at an end of the wiring pattern, and a wire bonding machine. And a magnetic oxygen analyzer comprising a lead wire connected between the sensor element and the bonding pad. A unit comprising the flow sensor of the magnetic oxygen analyzer according to claim 1,
Comprising a block body having the bypass flow path and a sensor arrangement space formed in the middle of the bypass flow path and opened to the outside;
A sensor unit for a magnetic oxygen analyzer, wherein the flow sensor is arranged in the middle of the bypass flow path by arranging the flow sensor in the sensor arrangement space from an opening.   The flow sensor arranged in the sensor arrangement space is configured such that the substrate is fixed to the bottom of the sensor arrangement space, and a closing member integrated with the substrate forms an opening of the block body that forms the sensor arrangement space. 3. The sensor unit for a magnetic oxygen analyzer according to claim 2, wherein the sensor unit is closed.

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