DE2462331C3 - Gas detection element for intrinsically safe gas measuring devices - Google Patents
Gas detection element for intrinsically safe gas measuring devicesInfo
- Publication number
- DE2462331C3 DE2462331C3 DE19742462331 DE2462331A DE2462331C3 DE 2462331 C3 DE2462331 C3 DE 2462331C3 DE 19742462331 DE19742462331 DE 19742462331 DE 2462331 A DE2462331 A DE 2462331A DE 2462331 C3 DE2462331 C3 DE 2462331C3
- Authority
- DE
- Germany
- Prior art keywords
- detection element
- gas detection
- intrinsically safe
- gas
- helix
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/14—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of an electrically-heated body in dependence upon change of temperature
- G01N27/16—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of an electrically-heated body in dependence upon change of temperature caused by burning or catalytic oxidation of surrounding material to be tested, e.g. of gas
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)
Description
Die Erfindung bezieht sich auf ein Gasspürelement nach dem Oberbegriff des Anspruchs I.The invention relates to a gas detection element according to the preamble of claim I.
Ein bekanntes Gasspürelement dieser Art (Glückauf, Band 104 (1968), S. 127-135) dient zum Messen von Methan. Gegenüber Methan ist es insofern eigensicher als die Zündenergie von Methan oberhalb der Energie etwaiger Zündfunken liegt.A known gas detection element of this type (Glückauf, Volume 104 (1968), pp. 127-135) is used to measure Methane. In relation to methane it is intrinsically safe in that the ignition energy of methane is above the energy there is any ignition spark.
Bei einem weiteren Gasspürelement (s. GB-PS 84 184) liegt der Drahtdurchmesser bei 25,4 μηι. Diese Stärke ist ebenfalls noch zu groß, um eine Eigensicherheit des Stromkreises ohne Einkapselung desselben für beliebige Gase zu gewährleisten. Der Metalloxidkörper besteht aus Aluminiumoxid, in das Glas eingelagert ist.In another gas detection element (see GB-PS 84 184), the wire diameter is 25.4 μm. This strength is also still too great for an intrinsic safety of the circuit without encapsulation to ensure the same for any gases. The metal oxide body consists of aluminum oxide into which Glass is stored.
Schließlich ist auch noch ein Gasspürelement bekannt ■ (SMRE Digest, Gas Detection 1! (1972)), bei dem der Durchmesser des Drahtes 50 μηι ist und der Metalloxidkörper aus Thoriumoxid besteht. Auch ein Stromkreis mit diesem Element ist ohne Einkapselung für belieh;ge Gase nicht eigensicher.Finally, a gas detection element is also known (SMRE Digest, Gas Detection 1! (1972)) in which the diameter of the wire is 50 μm and the metal oxide body consists of thorium oxide. A circuit with this element can also be used without encapsulation ; ge gases not intrinsically safe.
in Der Erfindung liegt die Aufgabe zugrunde, ein Gasmeßgerät mit einem Gasspürelement derart auszubilden, daß das Gerät für beliebige Gase eigensicher ist.The invention is based on the object a To design gas measuring device with a gas detection element in such a way that the device is intrinsically safe for any gases.
Diese Aufgabe wird erfimlungsgemäß gelöst wie im
Kennzeichen des Anspruches 1 angegeben.
i> Auf diese Weise wird erreicht, daß die Ströme im
Stromkreis kleiner als 100 mA sind. Die Energie etwa auftretender Funken ist insofern kleiner als die
Zündenergie vorkommender Gase. Das Gerät ist somit auch ohne Einkapselung der stromführenden Teile
J» eigensicher. Die Zusammensetzung des Metalloxidkörpers
trägt der Tatsache Rechnung, daß der extrem dünne Wendeldraht in besonderer Weise gestützt
werden muß: Thoriumoxid ist stabiler als das bisher verwendete Aluminiumoxid und deshalb besser als
r> dieses für die Stützung des Drahtes geeignet. Der Zusatz von Aluminiumoxid ist andererseits erforderlich,
um die Ausdehnungseigenschaften des Körpers den Ausdehnungseigenschaften des Drahtes anzupassen.This object is achieved according to the invention as indicated in the characterizing part of claim 1.
i> In this way it is achieved that the currents in the circuit are less than 100 mA. In this respect, the energy of any sparks that occur is smaller than the ignition energy of gases that occur. The device is therefore intrinsically safe even without encapsulating the live parts. The composition of the metal oxide body takes into account the fact that the extremely thin helical wire must be supported in a special way: Thorium oxide is more stable than the previously used aluminum oxide and therefore better than this for supporting the wire. On the other hand, the addition of aluminum oxide is necessary in order to adapt the expansion properties of the body to the expansion properties of the wire.
Zur Herstellung des Metalloxidkörpers werden einer i» Thoriumnitratlösung 5—20% einer Lösung einer Aluminium-Verbindung zugesetzt. In diese werden die Wendeln in üblicher Weise eingetaucht und aufgeheizt.To produce the metal oxide body, 5-20% of a solution of a thorium nitrate solution is used Aluminum compound added. The coils are immersed in this in the usual way and heated.
Weiterbildungen der Erfindung sind Gegenstand der Unteransprüche.Further developments of the invention are the subject of the subclaims.
i"· In der Zeichnung sind zwei Ausführungsbeispiele schematisch dargestellt. Darin zeigti "· In the drawing are two exemplary embodiments shown schematically. In it shows
F i g. I eine erste Ausführungsform,F i g. I a first embodiment,
F i g. 2 eine zweite Ausführungsform undF i g. 2 a second embodiment and
Fig.3 einen Schnitt durch die Ausführungsform der »ι Fig.2.3 shows a section through the embodiment of »Ι Fig.2.
Das Element 1 besteht aus einer Drahtwendel 2, die mit einem Überzug 3 ummantelt ist, in den ein Katalysator 4 eingebettet ist.The element 1 consists of a wire coil 2, which is covered with a coating 3, in the one Catalyst 4 is embedded.
Ist der Metalloxidkörper hohl, wie im Falle der F i g. 2 <'> und 3, ist ein besonders geringer Energieaufwand zur Heizung des Elementes erforderlich.If the metal oxide body is hollow, as in the case of FIG. 2 <'> and 3, a particularly small amount of energy is required to heat the element.
Hierzu 1 Blatt Zeichnungen1 sheet of drawings
Claims (6)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19742462331 DE2462331C3 (en) | 1974-05-31 | 1974-05-31 | Gas detection element for intrinsically safe gas measuring devices |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19742462331 DE2462331C3 (en) | 1974-05-31 | 1974-05-31 | Gas detection element for intrinsically safe gas measuring devices |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| DE2462331A1 DE2462331A1 (en) | 1977-02-24 |
| DE2462331B2 DE2462331B2 (en) | 1980-05-08 |
| DE2462331C3 true DE2462331C3 (en) | 1981-01-29 |
Family
ID=5934961
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| DE19742462331 Expired DE2462331C3 (en) | 1974-05-31 | 1974-05-31 | Gas detection element for intrinsically safe gas measuring devices |
Country Status (1)
| Country | Link |
|---|---|
| DE (1) | DE2462331C3 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3906599A1 (en) * | 1989-03-02 | 1990-09-06 | Draegerwerk Ag | Compensation element for a measuring device for combustible gases |
-
1974
- 1974-05-31 DE DE19742462331 patent/DE2462331C3/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE2462331B2 (en) | 1980-05-08 |
| DE2462331A1 (en) | 1977-02-24 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C3 | Grant after two publication steps (3rd publication) |