DE8233765U1 - Magnetic-inductive flow meter for high temperatures - Google Patents

Description

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INTERATOM 24.657.0

Internationale Atomreaktorbau GmbH D-5060 Bergisch Gladbach 1

Magnetic-inductive flow meter for high temperatures

The present invention relates to a high temperature and magnetic inductive flow meter electrically poorly conductive liquids. Magnetic inductive flow meters have been in the art since known for a long time. A magnetic field running perpendicular to a flowing liquid causes due to of Lorenz forces, daö in the flowing liquid a voltage is built up which is perpendicular to the direction of the magnetic field and the direction of flow. With a given magnetic field, this voltage is proportional to the volume flow of the liquid. It is known, to measure this voltage with electrodes and to build flowmeters according to this system.

In a prospectus from Fischer & Porter GmbH, Göttingen (Cat. 1.2, 1982), newer flowmeters are described described according to this principle. To avoid electrochemical processes, these Flow meter not with a constant magnetic field, but operated with alternating current or pulsating direct current. For liquids with poor electrical conductivity is another problem to be aware of. A metallic pipeline would be contained in the liquid Short-circuit the resulting voltage and make a measurement impossible. Therefore need electromagnetic inductive Flow meters for liquids with poor electrical conductivity consist of a piece of pipe, soft

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is electrically insulated on the inside in the area of the magnetic field. The electrodes must then be isolated by the wall of the pipe section and through the insulation into the interior where they come into contact step with the liquid. From the above prospectus, flow meters are bad for electrical purposes conductive liquids known, which work according to this principle and inside with rubber, plastic or ceramic are coated. However, this design has an upper limit with regard to the maximum medium temperature, which is in the range of 180 ° C. For higher temperatures so far the problems that arise Insufficient temperature resistance of the lining or due to different expansion coefficients of Pipe section and lining as well as the tight implementation of the electrode leads do not result be solved satisfactorily.

The object of the present invention is a flow meter which can be used at significantly higher temperatures and is suitable for liquids with poor electrical conductivity.

To solve this problem, a flow meter according to the main claim is proposed. The ones described above Problems are solved in that there is no longer any layer of insulation firmly attached to the inside of the pipe section is connected, but as a whole a ceramic tube with a small amount of play in the pipe section is inserted and wedged in this torsion-proof. Since there is no fixed connection between the pipe section and If there is a ceramic tube, it cannot break or damage even with different thermal expansions come of isolation. In addition, there is also

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Guides in the ceramic tube are completely dispensed with and instead the leads of the electrodes are laid on the inside of the ceramic tube to its end and only then passed through the wall of the pipe section to the outside. Because the tight implementation of pipes poses no problem due to a metal wall, the aforementioned risks are avoided in this way.

Fundamental to this new type of construction is the knowledge that liquid can penetrate between Ceramic tube and wall of the pipe section does not have a negative effect on the measurement. Decisive is only that at the location of the induced voltage there is no short circuit across the pipe wall can.

In a further embodiment of the invention, the claim 2 proposed that the leads to the electrodes in the area of the ceramic tube through a ceramic sheath to isolate. At the end of the ceramic tube there is a transition point from which the mineral-insulated supply lines Sheathed measuring conductors exist, which are welded tightly into the wall of the pipe section can be. The use of mineral-insulated sheathed measuring conductors is particularly favorable because the bushings are tight of sheathed measuring conductors through metal walls are relatively easy to accomplish. Inside the Ceramic tube, however, this type of insulation cannot be used because the metallic jacket is there in turn would cause the short-circuit currents which one wants to avoid by the present construction. Ceramic tubes are therefore inside the ceramic tube or a ceramic mass is used to insulate the leads of the electrodes.

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In a further embodiment of the invention wildly proposed to produce the magnetic coils from high temperature-resistant coils. This enables a compact design of the flow meter without the coils having to be particularly cooled or arranged at a distance from the pipeline. High-temperature-resistant coils have so far been used, for example, in electromagnetic induction pumps.
10

An embodiment of the invention is shown in the drawing, namely shows
Fig. 1 is a longitudinal section through a flow meter according to the invention along the line III-III of Fig. 2,

FIG. 2 shows a cross section along the line I-I in FIG. 1

and
FIG. 3 shows a section along the line II-II in FIG. 1

Fig. 1 shows a pipe section 1, which on both Ends with flanges 2 is provided. Inside the pipe section 1, a ceramic tube 3 is inserted, which is more or less loose. This ceramic tube 3 is welded at its ends by somewhat conical holding pieces 4 and 5 wedged and by a tooth-shaped engagement of the holding piece 4 secured against rotation. The holding pieces 5 are not rotationally symmetrical parts but support the ceramic tube 3 so that there is space between them for laying cables. Internally of the ceramic tube 3 electrodes 6 are arranged, the leads along the inside of the ceramic tube 3 are relocated. The first piece 7 of these supply lines is insulated with the aid of a ceramic tube, and after a transition point 8 at the end of the ceramic tube 3, the leads are in mineral-insulated Mantelmeß-

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. ladders 9 continued. These sheathed test leads are on the bushings through the wall of the pipe section 1 tightly welded 10. In Fig. 1 dashed the position of the coils 11 is indicated, which is made up of Fig. 2 shows more clearly. These coils are accommodated in a housing 13 fastened to the pipe section 1. A terminal box 12 to accommodate the electrical Terminals are also attached to the pipe section.

Fig. 2 shows a cross section along the line I-I in Fig. 1 by a flow meter according to the invention. The high temperature resistant coils 11 and the magnetic cores are protected in a housing 13 on both sides of the pipe section 1. Materials with a high Curie point are used as magnetic sheets.

FIG. 3 shows a section through FIG. 1 along the line II-II. The holding pieces 5, which have a conical shape, are welded to the pipe section 1 and fix the ceramic tube 3 in its position. Between the holding pieces there remains space for laying the sheath measuring conductor 9, which is guided through the pipe wall in the area of the holding pieces 5 and 10 are welded to this.

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Claims (1)

if f t * ι * * 82P 67390E INTERATOM -6- 24.657.0 Internationale Atomreaktorbau GmbH D-5060 Bergisch Gladbach 1 Magnetic-inductive flow meter ^{: for} high temperatures sayings 1. Magnetic-inductive flow meter, consisting of an internally insulated pipe section (1) in which by externally attached magnetic coils (1.1). a magnetic field can be generated perpendicular to the direction of flow, wherein two or more electrodes (6) are arranged inside the pipeline, marked through the following features: a) The insulation (3) inside the pipe section Π> consists of a ceramic tube, which is inserted with little play and at the ends is wedged against rotation with retaining pieces (4, 5). b) The supply lines (7) to the electrodes (6) are laid on the inside of the ceramic tube (3) and only passed behind its end through the wall of the pipe piece (1). 2. Flow meter according to claim 1, marked net by the following features: a) The leads (7) of the E] electrodes (6) are in the area of the ceramic tube (3) insulated by a ceramic coating. b) There is a transition point at the end of the ceramic tube (3) (8), from which the supply lines consist of mineral-insulated sheathed measuring conductors (9), soft tightly into the wall of the pipe section (1) 11/29/82 Nw / Pa · ■ · 82P 673 οOE -7- 24.657.0 shrink wrapped. (10) are. 3, flow meter according to claim 1 or 2, g e k e η η is characterized by the following feature: a) The solenoid coils (11) are made of high temperature resistant en coils.