JP2006119003A - Flow rate detection element for infrared gas analyzer - Google Patents

Flow rate detection element for infrared gas analyzer Download PDF

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JP2006119003A
JP2006119003A JP2004307635A JP2004307635A JP2006119003A JP 2006119003 A JP2006119003 A JP 2006119003A JP 2004307635 A JP2004307635 A JP 2004307635A JP 2004307635 A JP2004307635 A JP 2004307635A JP 2006119003 A JP2006119003 A JP 2006119003A
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heater
substrate
flow rate
gas
meandering
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Takuya Ido
琢也 井戸
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Horiba Ltd
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Horiba Ltd
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<P>PROBLEM TO BE SOLVED: To provide a flow rate detection element for an infrared gas analyzer for attaining an improvement of sensing sensitivity and responsiveness without causing complication, large size, and cost increase of a structure. <P>SOLUTION: The flow rate detection element for an infrared gas analyzer includes a substrate 1 having a void part 1a as a gas flow passage, and a heater 4 for applying a constant voltage by being held in a meandering state through an insulation film 2 provided so as to block the void part 1a on the substrate 1. The flow rate detection element forms a plurality of gas flow passage holes 6 on an insulation film part except for a part holding the meandering heater 4, and arranges the meandering heater 4 except for a connection part 4b with an energization electrode 3 to the heater 4 in a region surrounded by a contour OL of the void part 1a on the substrate 1 so that the entire length part is not overlaid on the substrate 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、非分散型の赤外線ガス分析計（ＮＤＩＲ）の検出器として用いられる赤外線ガス分析計用流量検出素子に関する。詳しくは、測定対象ガスと同じ吸収特性を示すガスが充填され、測定セルに対して直列的または並列的に配置される二つのガス室を連通させるガス通路内に配置されるものであって、ガス流通路としての空洞部を有する基板と、この基板上に前記空洞部を遮るように設けられる絶縁膜を介して蛇行状態に保持されて一定電圧が印加されるヒータとを備え、この蛇行状ヒータを保持する部分を除く絶縁膜部分に複数のガス流通孔を形成してなる赤外線ガス分析計用流量検出素子に関する。   The present invention relates to a flow rate detecting element for an infrared gas analyzer used as a detector of a non-dispersive infrared gas analyzer (NDIR). Specifically, the gas having the same absorption characteristics as the measurement target gas is filled, and is disposed in a gas passage that connects two gas chambers disposed in series or in parallel to the measurement cell, A substrate having a cavity as a gas flow path, and a heater which is held in a meandering state and is applied with a constant voltage via an insulating film provided on the substrate so as to block the cavity. The present invention relates to a flow rate detection element for an infrared gas analyzer in which a plurality of gas flow holes are formed in an insulating film portion excluding a portion for holding a heater.

この種の一般的な赤外線ガス分析計用流量検出素子は、図６および図７に示すように、ニッケル等の金属箔からジグザク蛇行状に形成された二枚のヒータ５１ａ，５１ｂと、これらのヒータ５１ａ，５１ｂを相対向させて配置しかつ固定するためのガラス等の絶縁材料製の板材５２ａ，５２ｂとからなり、これら板材５２ａ，５２ｂに形成された開口５３ａ，５３ｂ内に蛇行状ヒータ５１ａ，５１ｂを位置させてそれら蛇行状ヒータ５１ａ，５１ｂの隣接する直線ヒータ部分間の隙間をガス流通路５４に形成して構成されていた。   As shown in FIGS. 6 and 7, this type of flow detector for a general infrared gas analyzer includes two heaters 51a and 51b formed in a zigzag meandering manner from a metal foil such as nickel, and the like. It consists of plate materials 52a and 52b made of an insulating material such as glass for arranging and fixing the heaters 51a and 51b opposite to each other, and meandering heaters 51a in openings 53a and 53b formed in these plate materials 52a and 52b. , 51b and a gap between adjacent linear heater portions of the meandering heaters 51a, 51b is formed in the gas flow passage 54.

このような赤外線ガス分析計用流量検出素子は、ヒータ５１ａ，５１ｂに一定電圧を印加して前記ガス室に充填されたガスの温度よりも一定の温度だけ高くなるように温度制御して使用される。そして、赤外線が照射されない非検出状態では、二つのヒータ５１ａ，５１ｂは、図７中に符号ａで示すような温度分布を呈しているが、一方のガス室に赤外線を照射する検出状態では、そのガス室内に充填されたガスが膨張して前記ガス流通路５４に他方のガス室に向かうガスの流れ５５が発生する。このガスの流れ５５によって、上流側（図７の左側に位置する）のヒータ５１ａは、ガスの流速に応じて冷却され、逆に、下流側（図７の右側に位置する）のヒータ５１ｂは、上流側のヒータ５１ａから奪われた熱により加熱されて、図７中に符号ｂで示すような温度分布を呈することになる。このような温度分布の変化によりヒータ５１ａ，５１ｂの抵抗値が変化するので、この抵抗値の変化量をホイートストンブリッジ回路を用いて電圧値として出力させることによってガス流量が検出される。この検出されたガス流量は、非分散型赤外線ガス分析計の測定セル（周知であるるため、図示省略する）に流通させた測定対象ガスによる赤外線吸収量（測定対象ガスの濃度）に対応しており、したがって、ガス流量を検出することで測定対象ガスの濃度を測定し分析を行なう。   Such an infrared gas analyzer flow rate detecting element is used by applying a constant voltage to the heaters 51a and 51b and controlling the temperature so as to be higher than the temperature of the gas filled in the gas chamber by a certain temperature. The And in the non-detection state where infrared rays are not irradiated, the two heaters 51a and 51b exhibit a temperature distribution as indicated by the symbol a in FIG. 7, but in the detection state where one gas chamber is irradiated with infrared rays, The gas filled in the gas chamber expands to generate a gas flow 55 in the gas flow passage 54 toward the other gas chamber. By this gas flow 55, the heater 51a on the upstream side (located on the left side in FIG. 7) is cooled according to the flow rate of the gas, and conversely, the heater 51b on the downstream side (located on the right side in FIG. 7) Then, it is heated by the heat deprived from the heater 51a on the upstream side, and exhibits a temperature distribution as shown by symbol b in FIG. Since the resistance values of the heaters 51a and 51b change due to such a change in temperature distribution, the gas flow rate is detected by outputting the change amount of the resistance value as a voltage value using a Wheatstone bridge circuit. This detected gas flow rate corresponds to the amount of infrared absorption (concentration of the measurement target gas) by the measurement target gas circulated in the measurement cell of the non-dispersion type infrared gas analyzer (not shown because it is well known). Therefore, the concentration of the measurement target gas is measured and analyzed by detecting the gas flow rate.

ところで、上記した構成の一般的な赤外線ガス分析計用流量検出素子においては、ヒータ５１ａ，５１ｂが単に蛇行状に形成されているものであるから、ホイートストーンブリッジ回路に電圧を印加した場合、ヒータ５１ａ，５１ｂの中心部が周辺部より温度が高くなる。その結果、ガスが流れた場合、ヒータ５１ａ，５１ｂの中心部の温度変化、即ち、感度と周辺部の温度に差が生じ、結果として得られる感度は小さいものとなってしまうという課題がある。   By the way, in the flow rate detecting element for a general infrared gas analyzer having the above-described configuration, since the heaters 51a and 51b are simply formed in a meandering shape, when a voltage is applied to the Wheatstone bridge circuit, The temperature of the central part of the heaters 51a and 51b is higher than that of the peripheral part. As a result, when the gas flows, there is a problem that the temperature change in the central part of the heaters 51a and 51b, that is, the difference between the sensitivity and the temperature of the peripheral part occurs, and the resulting sensitivity becomes small.

このような課題を解消するものとして、従来、絶縁膜を介して蛇行状に保持されるヒータにより囲まれる内部位置においてのみ、隣接する直線ヒータ部分で挟まれた隙間部分にその隙間面積よりも小さい流路面積に設定されるように複数のガス流通孔からなるガス流通路を形成することにより、ガス流通路を通過するガスとヒータとの間での熱授受がヒータの中央部分においてのみ行われ、その結果、熱授受の効率上昇により大きな出力を得て、検出感度及び応答性の向上を図らんとしたものが提案されている（例えば、特許文献１参照）。   In order to solve such a problem, conventionally, only at an internal position surrounded by a heater held in a meandering manner through an insulating film, the gap area sandwiched between adjacent linear heater parts is smaller than the gap area. By forming a gas flow path composed of a plurality of gas flow holes so as to be set to a flow path area, heat transfer between the gas passing through the gas flow path and the heater is performed only in the central portion of the heater. As a result, there has been proposed a device which has obtained a large output due to an increase in efficiency of heat transfer, and has aimed to improve detection sensitivity and responsiveness (see, for example, Patent Document 1).

また、ガス流通路としての空洞部を有する基板上で蛇行状ヒータの周辺部に補助加熱手段を設けて流量検出素子自体を加熱することによって、ヒータから基板への熱移動、つまり、放熱を補って空洞部領域内の平均温度を上昇させ、検出感度の向上を図らんとしたものも従来より提案されている（例えば、特許文献２参照）。   Further, by providing auxiliary heating means on the periphery of the meandering heater on the substrate having a hollow portion as a gas flow passage to heat the flow rate detecting element itself, heat transfer from the heater to the substrate, that is, heat dissipation is compensated. In order to improve the detection sensitivity by increasing the average temperature in the cavity region, there has been conventionally proposed (for example, see Patent Document 2).

特開２００３−５７０８７号公報JP 2003-57087 A 特開平９−２２９８５３号公報Japanese Patent Laid-Open No. 9-229853

しかし、上記した従来例はいずれも、蛇行状ヒータの一部が基板における空洞部の外郭線で囲まれた領域、すなわち、ガス流通路より外側にはみ出して基板と重なり接触し、ヒータから基板への熱伝導による放熱ロスがあり、その結果、ガス流通路の温度分布が一様でなくなり、検出感度及び応答性を十分に向上させることができないという問題がある。   However, in all of the conventional examples described above, a part of the meandering heater is surrounded by the outline of the hollow portion of the substrate, that is, protrudes outside the gas flow path and overlaps with the substrate to contact the substrate from the heater. As a result, there is a problem that the temperature distribution of the gas flow path is not uniform, and the detection sensitivity and responsiveness cannot be sufficiently improved.

特に、特許文献２等にみられるような補助加熱手段を設ける場合は、流量検出素子自体の構造が複雑化かつ大型化し製造コストが高くなるだけでなく、基板への放熱ロス以外に補助加熱のための電力消費も加わるために、消費電力が非常に大きくてランニングコストの上昇は避けられないという問題があった。   In particular, when an auxiliary heating means such as that disclosed in Patent Document 2 is provided, not only does the structure of the flow rate detecting element itself become complicated and large, and the manufacturing cost increases, but also auxiliary heating in addition to the heat dissipation loss to the substrate. Therefore, there is a problem that the power consumption is very large and the running cost is inevitably increased.

本発明は上述の実情に鑑みてなされたもので、その目的は、構造の複雑化、大型化並びにコストアップを招くことなく、検出感度及び応答性の向上を実現することができる赤外線ガス分析計用流量検出素子を提供することにある。   The present invention has been made in view of the above-described circumstances, and an object thereof is an infrared gas analyzer capable of improving detection sensitivity and responsiveness without causing a complicated structure, an increase in size, and an increase in cost. An object of the present invention is to provide a flow rate detecting element.

上記目的を達成するために、本発明に係る赤外線ガス分析計用流量検出素子は、測定対象ガスと同じ吸収特性を示すガスが充填された二つのガス室を連通させるガス通路内に配置される赤外線ガス分析計用流量検出素子であって、ガス流通路としての空洞部を有する基板と、この基板上に前記空洞部を遮るように設けられる絶縁膜を介して蛇行状態に保持されて一定電圧が印加されるヒータとを有し、この蛇行状ヒータを保持する部分を除く絶縁膜部分に複数のガス流通孔を形成してなる赤外線ガス分析計用流量検出素子において、前記ヒータへの通電用電極との接続部を除く蛇行状ヒータを、その全長部が前記基板と重ならないように基板における空洞部の外郭線で囲まれた領域内に配置していることを特徴としている。   In order to achieve the above object, the flow rate detecting element for an infrared gas analyzer according to the present invention is disposed in a gas passage that connects two gas chambers filled with a gas having the same absorption characteristics as the gas to be measured. A flow rate detecting element for an infrared gas analyzer, which is held in a meandering state via a substrate having a cavity as a gas flow path and an insulating film provided on the substrate so as to block the cavity. In a flow rate detecting element for an infrared gas analyzer, in which a plurality of gas flow holes are formed in an insulating film portion excluding a portion holding the meandering heater. The meandering heater excluding the connection portion with the electrode is arranged in a region surrounded by the outline of the hollow portion of the substrate so that the full length portion does not overlap the substrate.

上記構成の本発明によれば、一定電圧が印加される蛇行状ヒータの全長部が基板と接触しない領域内に配置されているため、ヒータから基板への熱伝導による放熱ロスを抑制してガス流通部付近の温度分布を一様にすることができるので、検出感度及び応答性の向上を実現することができる。また、基板への放熱ロスをヒータの配置工夫のみによって抑えることが可能で、その放熱を抑制するための補助加熱手段の設置は不要であるから、流量検出素子自体の構造の簡単化、小型化及び消費電力の低減化を図ることができるという効果を奏する。   According to the present invention having the above-described configuration, the entire length of the meandering heater to which a constant voltage is applied is disposed in a region that does not contact the substrate. Since the temperature distribution near the circulation part can be made uniform, the detection sensitivity and the response can be improved. In addition, heat dissipation loss to the substrate can be suppressed only by the arrangement of the heater, and it is not necessary to install auxiliary heating means to suppress the heat dissipation, so the structure of the flow rate detection element itself is simplified and downsized In addition, the power consumption can be reduced.

特に、請求項２に記載のように、前記ヒータへの通電用電極との接続部を除く蛇行状ヒータを、その全長部のうちの最も外周に位置する部分と前記基板における空洞部の外郭線との間に環状形の絶縁膜部分が存在するように前記空洞部の中央部付近に集約配置することにより、基板への放熱ロスを一層低減できるとともに、ヒータの全長が短くなり、同じ抵抗値の検出素子を形成する場合、ヒータ幅を細くして、より高密度にセンサを配置し、検出感度の一層の向上を図ることができる。   In particular, as described in claim 2, the meandering heater excluding the connection portion with the electrode for energization to the heater includes a portion located on the outermost periphery of the full length portion and a contour line of the cavity portion in the substrate. The heat dissipation loss to the substrate can be further reduced and the total length of the heater can be shortened, and the same resistance value can be obtained by centrally arranging the cavity in the vicinity of the center so that an annular insulating film portion exists between When the detection element is formed, the heater width can be narrowed and the sensors can be arranged at a higher density to further improve the detection sensitivity.

また、本発明に係る赤外線ガス分析計用流量検出素子において、請求項３に記載のように、前記ヒータへの通電用電極との接続部を除く蛇行状ヒータを、該蛇行状ヒータで囲まれる領域の温度が一様になるように、その全長に亘り一定のヒータ線間隔のもとで、通電用電極部に近い両側部分のヒータ線幅を、抵抗値を上げるために中央部分のヒータ線幅よりも細く形成する、もしくは、その全長に亘り一定のヒータ線幅のもとで、通電用電極部に近い両側部分のヒータ線間隔が中央部分のヒータ線間隔よりも小さく形成することによって、ガス流通部付近の中央部と周辺部との温度分布を一様にすることが可能となり、検出感度の一層の向上を図ることができる。   Further, in the flow rate detecting element for an infrared gas analyzer according to the present invention, as described in claim 3, the meandering heater excluding the connection portion with the energization electrode to the heater is surrounded by the meandering heater. In order to increase the resistance, the heater wire width at both sides close to the energizing electrode part is set at a constant heater wire interval over the entire length so that the temperature of the region is uniform. By forming it narrower than the width, or by forming the heater line interval on both sides close to the energizing electrode part smaller than the heater line interval in the central part under a constant heater line width over its entire length, It becomes possible to make the temperature distribution in the central part and the peripheral part near the gas circulation part uniform, and the detection sensitivity can be further improved.

以下、本発明の実施の形態を、図面を参照しながら説明する。
図１は、本発明に係る赤外線ガス分析計用流量検出素子（以下、単に流量検出素子という）Ａの平面図、図２は図１のＸ−Ｘ線に沿った縦断面図、図３は図１のＹ−Ｙ線に沿った縦断面図である。この流量検出素子Ａは、図６および図７に示した一般的な流量検出素子と同様に、測定対象ガスと同じ吸収特性を示すガスが充填された二つのガス室を連通させるガス通路に、このガス通路と直交するように配置されるものであって、同一形状、同一構造の二つの検出素子単位体Ａ１，Ａ１を二段重ねに接着して構成されている。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a plan view of a flow rate detecting element (hereinafter simply referred to as a flow rate detecting element) A for an infrared gas analyzer according to the present invention, FIG. 2 is a longitudinal sectional view taken along line XX of FIG. It is a longitudinal cross-sectional view along the YY line of FIG. This flow rate detection element A is similar to the general flow rate detection element shown in FIGS. 6 and 7 in a gas passage that connects two gas chambers filled with a gas having the same absorption characteristics as the measurement target gas. The two detection element units A1 and A1 having the same shape and the same structure are arranged in two layers so as to be orthogonal to the gas passage.

この流量検出素子Ａの検出素子単位体Ａ１は、ガス流通路としての空洞部１ａを有する基板１と、この基板１上に前記空洞部１ａを遮るように設けられた絶縁膜２を介して蛇行状のパターン形状に保持されて通電用電極３，３により一定電圧が印加されるヒータ４とを有し、この蛇行状ヒータ４を保持する部分を除く絶縁膜２部分で隣接する直線ヒータ部分４ａ，４ａで挟まれた隙間部分５にそれぞれ、前記空洞部１ａに連通接続される状態で複数の長円状ガス流通孔６が形成されている。   The detection element unit A1 of the flow rate detection element A meanders through a substrate 1 having a cavity 1a as a gas flow path and an insulating film 2 provided on the substrate 1 so as to block the cavity 1a. And a heater 4 to which a constant voltage is applied by the energizing electrodes 3 and 3, and a linear heater portion 4a adjacent to the insulating film 2 portion excluding the portion holding the meandering heater 4 , 4a, a plurality of oval gas flow holes 6 are formed in a state of being connected to the cavity 1a.

ここで、前記検出素子単位体Ａ１の製造方法の一例を簡単に説明すると、前記基板１は非晶質のガラスやＳｉ、ＭｇＯ等の結晶性材料から形成され、この基板１上に、例えば、Ｐｔ、ＮｉまたはＮｉＣｒなどの温度係数の高い材料を例えばスパッタ法によって０．１〜０．５μｍ厚で蛇行状に堆積させ、かつ、露光して所定パターンのヒータ４を形成した後、前記基板１上に感光性ポリイミドやエポキシ系の有機系絶縁薄膜やＳｉＯ2 等の無機系絶縁薄膜を０．５〜３μｍ厚に堆積させ、かつ、露光することにより前記蛇行状パターンのヒータ４をその上部から保持する絶縁膜２を形成し、その後、基板１をその裏面側からエッチングすることにより、ガス流通路としての空洞部１ａを形成する。 Here, an example of a manufacturing method of the detection element unit A1 will be briefly described. The substrate 1 is formed of amorphous glass or a crystalline material such as Si or MgO. A material having a high temperature coefficient such as Pt, Ni or NiCr is deposited in a meandering manner with a thickness of 0.1 to 0.5 μm, for example, by sputtering, and is exposed to form a heater 4 having a predetermined pattern. A photosensitive polyimide, an epoxy-based organic insulating thin film, or an inorganic insulating thin film such as SiO 2 is deposited to a thickness of 0.5 to 3 μm on the top, and the heater 4 having the meandering pattern is formed from above by exposing it. The insulating film 2 to be held is formed, and then the substrate 1 is etched from the back side thereof to form a cavity 1a as a gas flow path.

上例のような製造方法で製造される流量検出素子Ａにおける各検出素子単位体Ａ１において、前記蛇行状ヒータ４は、通電用電極３，３との接続部４ｂ，４ｂを除く全長部が基板１と重ならないように、基板１における空洞部１ａの外郭線ＯＬで囲まれた領域内に配置されている。より具体的には、蛇行状ヒータ４の全長部のうち最も外周に位置する部分、即ち、隣接する直線ヒータ部分４ａ，４ａ間をそれぞれ繋ぐ各折返しヒータ部分４ｃ及び通電用電極３，３との接続部４ｂ，４ｂに連なる両側直線ヒータ部分４ｄ，４ｄと基板１の空洞部１ａの外郭線ＯＬとの間に環状形の絶縁膜部分２ａが存在するように空洞部１ａの中央部付近に集約配置されている。   In each detection element unit A1 in the flow rate detection element A manufactured by the manufacturing method as in the above example, the meandering heater 4 has a full-length portion excluding the connection portions 4b and 4b with the electrodes 3 and 3 for energization. The substrate 1 is disposed in a region surrounded by the outline OL of the cavity 1 a so as not to overlap with the substrate 1. More specifically, the portion located on the outermost part of the full length portion of the meandering heater 4, that is, the folded heater portions 4 c that connect the adjacent linear heater portions 4 a and 4 a and the energizing electrodes 3 and 3, respectively. The annular insulating film portion 2a exists between the linear heater portions 4d, 4d connected to the connecting portions 4b, 4b and the outer line OL of the cavity portion 1a of the substrate 1, and is concentrated near the center of the cavity portion 1a. Has been placed.

上記のように構成された流量検出素子Ａによれば、蛇行状ヒータ４の全長部が基板１と重ならない領域内でガス流通路としての空洞部１ａの中央部付近に集約的に配置されているために、ヒータ４から基板１への熱伝導による放熱ロスが抑制されガス流通部（空洞部１ａ及びガス流通孔６）付近の温度を一様に高めて大きな出力を得ることができる。また、ヒータ４の配置工夫のみによって基板１への放熱ロスを抑えることが可能で、放熱ロスを抑制するための補助加熱手段の設置は不要であるから、流量検出素子Ａ自体の構造の簡単化、小型化並びに製造コストの低減化が図れるとともに、補助加熱のための余分な電力消費がないことと基板１への放熱ロスを抑制することが相俟って、全体としての消費電力を著しく低減することが可能でありながら、検出感度及び応答性の向上を実現することができる。   According to the flow rate detecting element A configured as described above, the meandering heater 4 is arranged in a concentrated manner in the vicinity of the central portion of the hollow portion 1a as a gas flow path in a region where the meandering heater 4 does not overlap the substrate 1. Therefore, a heat dissipation loss due to heat conduction from the heater 4 to the substrate 1 is suppressed, and the temperature in the vicinity of the gas circulation part (the cavity part 1a and the gas circulation hole 6) can be uniformly increased to obtain a large output. Further, it is possible to suppress the heat dissipation loss to the substrate 1 only by arranging the heater 4, and it is not necessary to install auxiliary heating means for suppressing the heat dissipation loss. Therefore, the structure of the flow rate detection element A itself is simplified. In addition to reducing the size and manufacturing cost, the overall power consumption is significantly reduced due to the fact that there is no extra power consumption for auxiliary heating and the heat dissipation loss to the substrate 1 is suppressed. It is possible to improve detection sensitivity and responsiveness.

なお、上記の実施の形態では、蛇行状ヒータ４がその全長に亘って一定のヒータ線幅に形成されているもので示したが、図４に示すように、該蛇行状ヒータ４をその全長に亘り一定のヒータ線間隔としたうえで、通電用電極３，３に近い両側部分のヒータ線幅を中央部分のヒータ線幅よりも細く形成する、あるいは、図５に示すように、その全長に亘り一定のヒータ線幅としたうえで、通電用電極３，３に近い両側部分のヒータ線間隔を中央部分のヒータ線間隔よりも小さく形成することによって、ガス流通部の周辺部のジュール熱を中央部のジュール熱よりも大きくしてガス流通部付近の中央部と周辺部との温度分布を一様あるいはほぼ一様にすることが可能となり、その結果、中央部温度と周辺部温度の平均値として出力される電圧値を大きくし、検出感度の一層の向上を図ることができる。   In the above embodiment, the meandering heater 4 is shown as having a constant heater line width over its entire length. However, as shown in FIG. The heater line width at both sides close to the energizing electrodes 3 and 3 is made narrower than the heater line width at the center part, or as shown in FIG. In addition, the heater wire spacing at both sides close to the energizing electrodes 3 and 3 is made smaller than the heater wire spacing at the central portion, and the Joule heat at the peripheral portion of the gas circulation portion is made. Can be made larger than the Joule heat in the central part, and the temperature distribution in the central part and the peripheral part in the vicinity of the gas circulation part can be made uniform or almost uniform. The voltage value output as the average value Kikushi, it is possible to further improve the detection sensitivity.

本発明に係る赤外線ガス分析計用流量検出素子の平面図である。It is a top view of the flow volume detection element for infrared gas analyzers concerning the present invention. 図１のＸ−Ｘ線に沿った縦断面図である。It is a longitudinal cross-sectional view along the XX line of FIG. 図１のＹ−Ｙ線に沿った縦断面図である。It is a longitudinal cross-sectional view along the YY line of FIG. 流量検出素子における蛇行状ヒータの変形例を示す要部の平面図である。It is a top view of the principal part which shows the modification of the meandering heater in a flow volume detection element. 流量検出素子における蛇行状ヒータの他の変形例を示す要部の平面図である。It is a top view of the principal part which shows the other modification of the meandering heater in a flow volume detection element. 従来の熱式流量検出素子を示す平面図である。It is a top view which shows the conventional thermal type flow volume detection element. 図６のＶ−Ｖ線断面図である。It is the VV sectional view taken on the line of FIG.

符号の説明Explanation of symbols

Ａ 赤外線ガス分析計用流量検出素子
１ 基板
１ａ 空洞部
２ 絶縁膜
３ 通電用電極
４ 蛇行状ヒータ
４ａ 直線ヒータ部分
４ｂ 通電用電極との接続部
６ ガス流通孔
ＯＬ 空洞部の外郭線 A Flow detection element for infrared gas analyzer 1 Substrate 1a Cavity part 2 Insulating film 3 Electrode for energization 4 Meandering heater 4a Linear heater part 4b Connection part with electrode for energization 6 Gas flow hole OL Outline of cavity part

Claims (3)

測定対象ガスと同じ吸収特性を示すガスが充填された二つのガス室を連通させるガス通路内に配置される赤外線ガス分析計用流量検出素子であって、ガス流通路としての空洞部を有する基板と、この基板上に前記空洞部を遮るように設けられる絶縁膜を介して蛇行状態に保持されて一定電圧が印加されるヒータとを有し、この蛇行状ヒータを保持する部分を除く絶縁膜部分に複数のガス流通孔を形成してなる赤外線ガス分析計用流量検出素子において、
前記ヒータへの通電用電極との接続部を除く蛇行状ヒータを、その全長部が前記基板と重ならないように基板における空洞部の外郭線で囲まれた領域内に配置していることを特徴とする赤外線ガス分析計用流量検出素子。 A flow rate detection element for an infrared gas analyzer disposed in a gas passage that connects two gas chambers filled with a gas having the same absorption characteristics as the measurement target gas, and a substrate having a cavity as a gas flow passage And a heater that is held in a meandering state and is applied with a constant voltage via an insulating film provided on the substrate so as to block the cavity, and an insulating film excluding a portion that holds the meandering heater In the flow detection element for an infrared gas analyzer formed by forming a plurality of gas flow holes in the part,
The meandering heater excluding the connection portion with the energization electrode to the heater is arranged in a region surrounded by the outline of the hollow portion of the substrate so that the full length portion does not overlap the substrate. A flow rate detecting element for an infrared gas analyzer. 前記ヒータへの通電用電極との接続部を除く蛇行状ヒータが、その全長部のうちの最も外周に位置する部分と前記基板における空洞部の外郭線との間に環状形の絶縁膜部分が存在するように前記空洞部の中央部付近に集約配置されている請求項１に記載の赤外線ガス分析計用流量検出素子。   The serpentine heater, excluding the connection portion with the electrode for energization to the heater, has an annular insulating film portion between the outermost portion of the full length portion and the outline of the hollow portion of the substrate. The flow rate detecting element for an infrared gas analyzer according to claim 1, wherein the flow rate detecting element is centrally arranged near the center of the cavity so as to exist. 前記ヒータへの通電用電極との接続部を除く蛇行状ヒータは、該蛇行状ヒータで囲まれる領域の温度が一様になるように、その全長に亘り一定のヒータ線間隔のもとで、通電用電極部に近い両側部分のヒータ線幅が中央部分のヒータ線幅よりも細く形成されている、もしくは、その全長に亘り一定のヒータ線幅のもとで、通電用電極部に近い両側部分のヒータ線間隔が中央部分のヒータ線間隔よりも小さく形成されている請求項１または２に記載の赤外線ガス分析計用流量検出素子。   The meandering heater, excluding the connection portion with the energizing electrode to the heater, has a uniform heater line interval over its entire length so that the temperature of the region surrounded by the meandering heater is uniform. The heater line width on both sides close to the energizing electrode part is formed narrower than the heater line width on the center part, or both sides close to the energizing electrode part with a constant heater line width over its entire length The flow rate detection element for an infrared gas analyzer according to claim 1 or 2, wherein the heater wire interval of the portion is formed smaller than the heater wire interval of the central portion.
JP2004307635A 2004-10-22 2004-10-22 Flow rate detection element for infrared gas analyzer Pending JP2006119003A (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000009641A (en) * 1998-06-26 2000-01-14 Horiba Ltd Flow rate detection element for infrared gas analyzer and its manufacture
JP2001153707A (en) * 1999-11-30 2001-06-08 Denso Corp Flow sensor
JP2003057087A (en) * 2001-08-10 2003-02-26 Horiba Ltd Flow rate sensor for infrared gas analysis

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000009641A (en) * 1998-06-26 2000-01-14 Horiba Ltd Flow rate detection element for infrared gas analyzer and its manufacture
JP2001153707A (en) * 1999-11-30 2001-06-08 Denso Corp Flow sensor
JP2003057087A (en) * 2001-08-10 2003-02-26 Horiba Ltd Flow rate sensor for infrared gas analysis

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