DE2123371C

DE2123371C - Temperature measuring device for enamelled apparatus

Info

Publication number: DE2123371C
Application number: DE19712123371
Authority: DE
Inventors: Rudi 6830 Schwetzmgen Horsch
Original assignee: Pfaudler Werke GmbH
Current assignee: Pfaudler GmbH
Filing date: 1971-05-11
Publication date: 1973-05-24

Description

wähnte mechanische Beanspruchung des Wider- Widerstand 100 Ohm betragen soll. Für die Meßstandsdrahts umso großer, je länger der Widerstands- schleife findet vorzugsweise ein flacher bandförmiger draht ist. Andererseits darf der bandförmige Wider- Platindraht Verwendung, der unter der genannten stand nicht zu dünn sein, weil gewisse Restspannun- Voraussetzung einen Querschnitt von etwa 0,003 mm-' gen emailliertechnisch nicht vermeidbar sind, und 5 und eine Länge von 3 m hat. Bei dem dargestellten weil der Widerstandsdraht bei der manuellen Anord- Ausführungsbeispiel ist die Meßschleife entlang langnung bei zu ounner Ausbildung beschädigt werden gezogener paralleler Bahnen angeordnet, um den Mitkonnte ohne daß gefährliche Fehlstellen sofort er- telwert der Temperatur innerhalb eines größeren Vokennbar sind. Praktische Erfahrungen haben gezeigt, lumens zu messen. Wenn jedoch lediglich die Tempedaü die Verwendung eines bandförmigen Platindrahts io ratur einer sehr schmalen Zone erfaßt werden soll, mit einem Querschnitt von etwa 0,003 mm* besonders kann die Meßschleife wendelförmig um das Rohr gevorteilhaft ist wickelt werden. Offensichtlich kann die dargestellte An Hand des m der Zeichnung dargestellten Aus- Vierleiterschaltung auch als Dreileiterschaltung oder funrungsbeispiels soll die Erfindung näher erläutert als Zweileiterschaltung benutzt werden,
werden, bs zeigt _{l5 Danach} erfolgt das Überemaillieren der Zuleitun- b ig. 1 ein mit einer ersten Deckemailschicht verse- gen und der Meßschleife durch zwei bis drei weitere henes Rohr, auf welches gemäß dem Verfahren der Deckemailschichten. Hierbei wird jedoch ein kleines hrtindung zunächst die Widerstandsdrähte aufgelegt Fenster mit einer Abmessunp von etwa 2 X 6 cm mm werden, und Emailauftrag ausgespart, wie ·η Fig. 2 dargestellt ist. Mg. 2 die Aussparung des Fensters rieh dem Auf- ao Dieses FensterF befindet sich über demjenigen Bebnngen einer weiteren Deckemailschicht bei dem reich der Meßschleife, daß bei geeigneter Überbrük-V erfahren gemäß der Erfindung. kung durch eine Drahtbrücke S ein Widerstand der ^D*^s. "L.^lg·' ^dargestellte Rohr kann irgendein M'ißschleife von 100 Ohm erzieibar ist. Eine geeigemai lierfahiger Korper sein, auf dessen erster Deck- nete Anordnung der Drahtbrücke 5 kann mit Hilfe emailschicht die Widerstandsdrähte vor dem Auftragen 25 einer Konstantstromquelle, eines Kompensationsvereiner weiteren Deckemailschicht angeordnet werden. stärkers und unter Berücksichtigung der Drahttempe-Bei diesem Ausführungsbeispiel handelt es sich um ratur nach dem Vierleiterprinzip genau bestimmt wereine Vierleiterschaltung, deren Verwendung ebenso den. Nach einer geeigneten Anordnung der Drahtwie andere Brückenschaltungen bei Widerstandsther- brücke 5 wird im Bereich des Fensters F Emaille aufmometern bekannt ist, um die Messung unabhängig 30 getragen und eingebrannt, wodurch die Meßschleife von den Zuleitungswiderständen zu machen. An die und die Zuleitungen elektrisch isoliert und korro-Anschlüsse A, B und C, D der Zuleitungen wird bei sionsgeschützt sind. Die durch das abschließende der schließlichen Montage ein Klemmkasten zur Ver- Überemaillieren des Fensters verursachte Änderung bindung mit der übrigen Meßeinrichtung angeschlos- des Meßwiderstands ist vernarhlässigbar, weil dasen. Die Zuleitungen sind beispielsweise Platindrähte, 35 durch lediglich Änderungen bewirkt werden, die indie an den Verbindungsstellen 1 und 2 durch je eine nerhalb der zulässigen Toleranzen für übliche Wider-Drahtbrurke verbunden sind, an weiche die Enden Standsthermometer liegen.imagined mechanical stress on the resistance should be 100 ohms. For the measuring station wire, the longer the resistance loop is, the larger it is, preferably a flat, band-shaped wire. On the other hand, the band-shaped resistance platinum wire must not be too thin, because certain residual stresses cannot be avoided from an enamelling point of view. In the illustrated because the resistance wire in the manual arrangement embodiment, the measuring loop is arranged along the length of the drawn parallel paths are damaged if the formation is too low, so that the co-operator can immediately get a value of the temperature within a larger range without dangerous defects. Practical experience has shown that lumens can be measured. However, if only the tempedaü the use of a band-shaped platinum wire io temperature of a very narrow zone is to be detected, with a cross-section of about 0.003 mm * especially the measuring loop can be wound helically around the pipe, which is advantageous. Obviously, the four-wire circuit shown on the basis of the m of the drawing can also be used as a three-wire circuit or a functional example, the invention is to be explained in more detail as a two-wire circuit,
are, bs shows _{l5 is followed} by the Überemaillieren the Zuleitun- b ig. 1 singe a first cover enamel layer and the measuring loop through two to three further tubes, onto which, according to the method of cover enamel layers. In this case, however, a small herniation is first placed on the resistance wires, windows with a dimension of about 2 × 6 cm mm , and enamel application is omitted, as shown in FIG. 2. Mg. 2 The recess of the window rieh the open- ao This window F is located above that leveling of a further cover enamel layer in the area of the measuring loop that with suitable bridging methods according to the invention. kung by a wire bridge S a resistance of the ^D * ^s . "L. ^lg · ^'represents asked tube may be any M'ißschleife of 100 ohms is erzieibar. A geeigemai lierfahiger body be designated on its first deck arrangement of the wire bridge 5 can with the aid of the enamel layer, the resistance wires before applying 25 a constant current source, a In this embodiment, the temperature is precisely determined according to the four-wire principle, the use of which is also the the window F enamel aufmometern is known, worn and the measurement independent 30 baked, thereby to make the measuring loop of the lead resistances. at the and the leads are electrically insulated and KORRO ports A, B and C, D of the leads is are at sion protected . The through the final The final assembly of a terminal box for over-enamelling the window caused the change in the connection with the rest of the measuring device connected. The measuring resistor is negligible because this. The supply lines are, for example, platinum wires, which are only effected by changes that are connected to the connection points 1 and 2 by one each within the permissible tolerances for the usual resistance wire, on which the ends of the standing thermometer are located.

der Meßschleife £ angeschlossen sind. Das kurze Durch die Erfindung ist es deshalb möglich,connected to the measuring loop £. The short by the invention it is therefore possible

bnde der Meßschleife £ wird durch eine Draht- üblicherweise in der Meß- und Regeltechnik gefor-The end of the measuring loop £ is required by a wire - usually in measurement and control technology.

brucke 3 an einer Stelle überbrückt, die bei Raumtem- 40 derte Normwiderstände auch für Widemandsdrähte,bridge 3 bridged at one point, which is also 40 for room tempered standard resistances for widemand wires,

Kro^tUui^etc^{Wa einen Widerstand von} 115 Ohm der welche in einer Emailschicht eingeschmolzen sind, inKro ^tU ui ^et c ^{Wa a resistance of} 115 ohms which are fused in an enamel layer, in

Meßschleife £ ergibt, wenn der vorherbestimmbare einer vorherbestimmbaren Weise vorzusehen.Measurement loop £ results when the predeterminable is provided in a predeterminable manner.

Hierzu 1 Blatt Zeichnung«!1 sheet of drawing «!

Claims

are increased because those in the enamel layer Si-SSS = S

1. Temperature measuring device for enamelled can. To avoid apparatus embedded in the enamel layer 5, it is bek _£ nnt (German resistance wire, characterized g Eke η η - draws prior to application of that the embedded resistive wire core with "ner thin is band-shaped and ren a resistance up, which for inclusion

which is adjusted by a tuning member. gen or the this stutzend »^^^^

2. Temperature measuring device according to claim 1 i. should also in dieGnindemailschichtlNuten_zur on for an enameled pipe, characterized gekennzeich- the Meßwicklungeingeatztwe would deprive ^ Beid sem * net, that the resistance wire helically Toggle known method, ^"see alsnachteilig ^. It is ordered that it is comparatively complicated and not without it

- ^g 3 temperature measuring device according to claim 1 further for steel enamel. usable «t is also or 2, characterized! ?. that the bandför- i ₅ is not is a platinum wire with a resistance thermometers with f ^ ^htfo ™> S ^en ™ ^ß "Ouerschnitt of about 0.00 mm * readily moglicl, ^ ¹ other-shaped resistance wire loops usual adjustment; desW .d «tand you

4. Process for the production of a temperature bridging a measuring loop to the original measuring device for enamelled apparatus according to (USA.-Patentschnft 2 926 3 ~ ^ü > _ EineTemrw

one of the preceding claims, in which ao It is therefore the task of de. Erfindu £ | £ ™ ^T ™ P-resistance wires between übereinanderliegen- raturmeßeinrichtung for ^emailIl _pr ^ ^ P ^p _n I Sahi ύπ the enamel layers are melted DA, the enamel layer "ngebetteiem W.derrtandsdral" and characterized by that on a deck a process for the production of which was carried out with a window over the area of a low force on the sensitive measuring elements, even though the enamel layer was laid with a layer of enamel Measuring loop with the following top layer of enamel, which is coated and fused with resistance and strength so that a predetermined resistance can be achieved in the area of this window. Adjacent pieces of wire.

The measuring loop can be bridged as a tuning element according to the direction for enamelled apparatus with a _{resistance wire embedded in the tm M} .ie a predetermined resistance of the measuring layer, and that d-nn is appropriately solved by the embedded Wiik-rreich of the window is band-shaped with at least one further stand wire and has a resistor aiif cover enamel layer coated and fused, which is set by a tuning glicd. . _d ⁶ _The adjustment of the resistance by means of a

35 vocal member can be done by the fact that the enamel layer over an area of a punched measuring

loop is removed to bypass it

to enable a cross-connection. This rue is then covered again with a layer of enamel.

The invention relates to a Temperaturmeßein- ₄ ° The preferred method for preparing a the direction for enameled apparatuses with like in the enamel Temperaturmeßeinnchtung enameled for layer embedded resistance wire and an apparatus, wherein the resistor wires between about methods for producing such a temperature-side enamel layer ™ melted down tower measuring device for enamelled apparatus. are, however, is characterized according to the invention

In practice, it has been found that the temperature measurement system has been placed on top of a layer of enamel devices for enamelled apparatus thermo-resistance wire with the exception of a window over ler made of tantalum or enamelled temperature protection - the area of a measuring loop with the following tubes to accommodate a mercury thermometer, cover r.ail layer is coated and fused, a resistance thermometer or a thermometer that in the area of this window adjacent wire element Use. Furthermore, 50 pieces of the measuring loop have already been proposed as tuning elements (German Patent 1 648 277), a Ther- chend a predetermined resistance of the measuring element loop partially bridged into the enamel layer and that then the area zen in order to increase the speed of response to the window with at least one further deck targets. When it is used, however, the enamel layer is coated and fused. Difficulty that in chemical factories often 55 When the temperature measurement on one existing measuring equipment and control equipment is to be provided, the Resistance wire is not conveniently helical for temperature measurement with thermocouples are suitable and that the off is arranged. In this way it can be prevented output signals of a thermocouple relatively that a relatively thin ribbon-shaped counter weak are. 60 Stand wire breaks because it only sticks during the burn-in process

It is also known to apply an enamel layer to metallic support body at the upper end attachable thermometer tube un- ^ per first and uniform enamel flow processes occur that wrap the measuring wire and use another enamel layer by shifting individual wire sections as a protective layer. These are largely compensated for as long as the temperature required for firing enamel layers is still at the firing temperature, but doors are so high that the strength of the enameling is technically desirable that ]

Platinum wire and the wire a certain the ribbon-shaped resistance wire as possible ' BrittleV.jit receives. The existing difficulties have low cross-section. In addition, the ^;