JPH0448528Y2

JPH0448528Y2 -

Info

Publication number: JPH0448528Y2
Application number: JP1983199276U
Authority: JP
Priority date: 1983-12-28
Filing date: 1983-12-28
Publication date: 1992-11-16
Also published as: JPS60109044U

Description

[Detailed explanation of the idea]

この考案は、都市ガスを自然発生メタンや
LPG、ガソリン等と識別して検知できるように
し、しかも中央処理装置（以下CPUという）に
より電極電圧のチエツクと、ゼロ調整とを自動的
に行い、それらの結果をLCD（液晶）表示器に表
示させるようにした識別型ガス検知装置に関する
ものである。都市ガスは、CH₄を主成分とし、ブタン、プロ
パン、エタン等の可燃性ガスを含む天然ガス
（13Aガス）と、CH₄，H₂等を主成分とする製造
ガス（6C，6Bガス等）とに大別される。以下、
天然ガスと他の可燃性ガスとの識別について述べ
るが、製造ガスと他の可燃性ガスとの識別につい
ても全く同様である。天然ガスの場合、主成分はメタンであり、天然
ガスのガス漏洩検知はメタン用ガスセンサを使用
して行われる。ところが、この場合に自然発生メタン（純メタ
ン）を検知して都市ガスの漏洩と誤認する場合が
多く、そのために不必要な路面の掘削を行うなど
労力と経費の無駄が多かつた。この考案は、上記の点にかんがみなされたもの
で、メタンを含む可燃性ガスに感度を有する第１
のガスセンサと、メタンを除く可燃性ガスに感度
を有する第２のガスセンサとを使用して、通常は
第１のガスセンサの出力によりその濃度をLCD
表示器に指示させ、かつ第１のガスセンサおよび
第２のガスセンサの出力の比較により、天然ガ
ス、自然発生メタン、LPG、ガソリンのい
ずれのガスであるかが表示できるようにするとと
もに、ゼロ調整、電源電圧チエツク等を内部の
CPUで行い、これらの手順ならびに結果をLCD
表示器に表示させるようにしたものである。まず、この考案の測定原理を簡単に説明する。
この考案では第１のガスセンサと第２のガスセン
サとを用いるが、それらの特性を示すと第１図、
第２図、第３図のようになる。第１図は自然発生メタン（純メタン）濃度指示
特性で、縦軸は、13AガスがLEL100％のときの
ガスセンサの出力（単位は、例えばmV）を100
とし、横軸にガス濃度（Vo1.％）LEL（爆発下限
濃度）（％）をとつて示す。なお、爆発下限界と
は、可燃性ガスが空気と混合している場合、混合
ガスの組成がある範囲にあるとき、火源を近づけ
ると爆発現象が起る。この濃度の一定範囲を爆発
範囲といい、その最低濃度を爆発下限界という。
曲線Ｉは第１のガスセンサ、曲線IIは第２のガス
センサの特性である（以下同じ）。第２図は同様に都市ガス（天然ガス13A）、第
３図は同じくガソリンの場合である。なお、第３図のガス濃度（Vo1.％）、LEL（％）
のスケールの単位が第１図、第２図と異つている
のは、第３図のガソリンの場合は低いガス濃度で
も第２のガスセンサの出力が大きいので第１
図、第２図と同じスケールにすると殆んど垂直と
なつて読み取り難いためである。これからわかるように、第１、第２のガスセン
サの出力の組合わせから何のガスであるかが判別
できる。これを表示すれば下記第１表のようにな
る。 This idea replaces city gas with naturally occurring methane.
It is designed to be able to identify and detect LPG, gasoline, etc., and the central processing unit (hereinafter referred to as CPU) automatically checks the electrode voltage and performs zero adjustment, and displays the results on the LCD (liquid crystal) display. The present invention relates to an identification type gas detection device that is configured to City gas consists of natural gas (13A gas) whose main component is CH ₄ and flammable gases such as butane, propane, and ethane, and manufactured gas (6C, 6B gas, etc.) whose main components are CH ₄ and H _2, etc. ). below,
Discrimination between natural gas and other combustible gases will be described, but the same applies to the distinction between manufactured gas and other combustible gases. In the case of natural gas, the main component is methane, and gas leak detection for natural gas is performed using a methane gas sensor. However, in many cases, naturally occurring methane (pure methane) is detected and misidentified as a city gas leak, resulting in unnecessary road surface excavation, which results in a lot of wasted labor and money. This idea was developed in consideration of the above points, and is a first method that is sensitive to flammable gases including methane.
using a gas sensor and a second gas sensor sensitive to flammable gases other than methane, the concentration of which is usually displayed on the LCD based on the output of the first gas sensor.
It is possible to display whether the gas is natural gas, naturally occurring methane, LPG, or gasoline by instructing the display and comparing the outputs of the first gas sensor and the second gas sensor. Internal power supply voltage check etc.
Performed on CPU, these steps and results are displayed on LCD
This is displayed on a display. First, the measurement principle of this invention will be briefly explained.
This invention uses a first gas sensor and a second gas sensor, and their characteristics are shown in Figure 1.
It will look like Figures 2 and 3. Figure 1 shows the concentration indicator characteristics of naturally occurring methane (pure methane), and the vertical axis shows the gas sensor output (unit: mV, for example) when 13A gas is at 100% LEL.
The horizontal axis shows gas concentration (Vo1.%) and LEL (lower explosive limit concentration) (%). The lower explosive limit means that when a flammable gas is mixed with air, an explosion occurs when a fire source is brought close to the mixture when the composition of the mixed gas is within a certain range. This certain range of concentration is called the explosive range, and the lowest concentration is called the lower explosive limit.
Curve I is the characteristic of the first gas sensor, and curve II is the characteristic of the second gas sensor (the same applies hereinafter). Figure 2 similarly shows the case of city gas (natural gas 13A), and Figure 3 similarly shows the case of gasoline. In addition, gas concentration (Vo1.%) and LEL (%) in Figure 3
The reason why the scale unit is different from that in Figures 1 and 2 is that in the case of gasoline in Figure 3, the output of the second gas sensor is large even at low gas concentrations, so the output of the second gas sensor is large.
This is because if it were set to the same scale as Figure 2, it would be almost vertical and difficult to read. As can be seen from this, the type of gas can be determined from the combination of the outputs of the first and second gas sensors. If this is displayed, it will look like Table 1 below.

[Effect of idea]

以上詳細に説明したように、この考案は、メタ
ンを含む可燃性ガスに感度を有する第１のガスセ
ンサと、メタンを除く可燃性ガスに感度を有する
第２のガスセンサと、第１または第２のガスセン
サの出力によるガス濃度およびガス種別を表示す
るためのLCD表示器と、識別押しボタンとを設
け、さらに識別押しボタンを押す以前は第１のガ
スセンサの出力によるガス濃度をLCD表示器に
表示させ、識別押しボタンを押すと第１と第２の
ガスセンサの出力によるそれぞれのガス濃度を一
定時間表示させる手段と、一定時間の表示後、第
１のガスセンサによるガス濃度と第２のガスセン
サの出力によるガス濃度との比が一定の範囲内で
あることを検出する手段と、一定の範囲に相当す
るガス種別を表示させる手段と、各測定前に電源
電圧が規定値以上あるかどうかをチエツクする手
段と、さらにゼロ調整を自動的に行わせる手段と
を備えた中央処理装置を設けた構成としたので、
測定前に必ず電圧チエツクと自動零点調整が行わ
れるので、電源電池の消耗に基づく誤差や、零調
整不良による誤差は入らない。そして、通常は、
第１のガスセンサの出力によるメタンを含む可燃
性ガスのガス濃度が表示され、通常のガスもれ警
報と同じ機能を有し、識別押しボタンを押すと第
１のガスセンサの出力によるガス濃度とともに、
第２のガスセンサによるメタンを除く可燃性ガス
のガス濃度が並置して一定時間表示され、その
後、中央処理装置による演算により得られたガス
種別が表示される。したがつて、使用者は、第１、第２のガスセン
サによるガス濃度から経験的にガス種別を判定す
る作業から開放され、自動的にガス種別を知るこ
とができ、従来のように自然発生メタンと都市ガ
スとを誤認するおそれがなく、かつ精度の高い、
小形で操作性にすぐれた識別型ガス検知装置が得
られる利点がある。 As explained in detail above, this invention includes a first gas sensor sensitive to flammable gases including methane, a second gas sensor sensitive to flammable gases other than methane, and a first or second gas sensor sensitive to flammable gases including methane. An LCD display for displaying the gas concentration and gas type based on the output of the gas sensor and an identification push button are provided, and furthermore, the gas concentration based on the output of the first gas sensor is displayed on the LCD display before the identification push button is pressed. , means for displaying the respective gas concentrations based on the outputs of the first and second gas sensors for a certain period of time when an identification push button is pressed; A means for detecting that the ratio to the gas concentration is within a certain range, a means for displaying the gas type corresponding to the certain range, and a means for checking whether the power supply voltage is above a specified value before each measurement. Since the configuration includes a central processing unit equipped with a means for automatically performing zero adjustment,
Since a voltage check and automatic zero point adjustment are always performed before measurement, there are no errors due to power battery consumption or errors due to faulty zero adjustment. And usually,
The gas concentration of flammable gases including methane is displayed according to the output of the first gas sensor, and has the same function as a normal gas leak alarm.When the identification push button is pressed, the gas concentration according to the output of the first gas sensor is displayed.
The gas concentrations of combustible gases other than methane measured by the second gas sensor are displayed side by side for a certain period of time, and then the gas type obtained by calculation by the central processing unit is displayed. Therefore, the user is freed from the task of determining the gas type empirically from the gas concentration measured by the first and second gas sensors, and can automatically know the gas type, and can detect naturally occurring methane as before. There is no risk of misidentifying city gas with city gas, and there is a high degree of accuracy.
This has the advantage of providing an identification type gas detection device that is small and has excellent operability.

[Brief explanation of the drawing]

第１図、第２図、第３図はこの考案に用いるガ
スセンサのガス濃度指示計の各種ガスに対する指
示特性図、第４図にこの考案の一実施例を示すガ
ス回路と電気回路のブロツク図、第５図は第４図
の実施例の動作を説明するためのフローチヤー
ト、第６図はパネルの一例を示す平面図である。図中、１はガス取入口、２はガス排出口、３は
流路、４は第１のガスセンサ、５は第２のガスセ
ンサ、６はポンプ、７，８は増幅器、９はアナロ
グスイツチ、１０はＡ・Ｄコンバータ、１１は
CPU、１２はLCD表示器、１３は電源、１４は
電源スイツチ、１５，１６は定電圧回路、１７は
ゼロ押しボタン、１８は識別押しボタン、１９は
識別解除ボタンである。 Figures 1, 2, and 3 are characteristic diagrams for various gases of the gas concentration indicator of the gas sensor used in this invention, and Figure 4 is a block diagram of a gas circuit and an electric circuit showing an embodiment of this invention. , FIG. 5 is a flowchart for explaining the operation of the embodiment shown in FIG. 4, and FIG. 6 is a plan view showing an example of the panel. In the figure, 1 is a gas intake port, 2 is a gas outlet, 3 is a flow path, 4 is a first gas sensor, 5 is a second gas sensor, 6 is a pump, 7 and 8 are amplifiers, 9 is an analog switch, and 10 is A/D converter, 11 is
12 is an LCD display, 13 is a power source, 14 is a power switch, 15 and 16 are constant voltage circuits, 17 is a zero push button, 18 is an identification push button, and 19 is an identification release button.

Claims

[Scope of utility model registration request]

a first gas sensor sensitive to flammable gases including methane; a second gas sensor sensitive to flammable gases other than methane;
an LCD display for displaying the gas concentration and gas type based on the output of the first gas sensor; and an identification push button; further, before the identification push button is pressed, the gas concentration based on the output of the first gas sensor is displayed on the LCD means for displaying the respective gas concentrations according to the outputs of the first and second gas sensors for a certain period of time when the identification push button is pressed; means for detecting that the ratio between the gas concentration and the gas concentration determined by the output of the second gas sensor is within a predetermined range; means for displaying the type of gas corresponding to the predetermined range; What is claimed is: 1. An identification type gas detection device, characterized in that it is provided with a central processing unit equipped with a means for checking whether or not the above is present, and a means for automatically performing zero adjustment.