FR2689631A1 - Electrical thermometer having an instrumentation passage piece resistant to pressure and corrosion. - Google Patents

Abstract

a) Electric thermometer having an instrumentation passage part resistant to pressure and corrosion, b) characterized by the fact that the rear end of the protection tube (1) and the connection box (8) are connected together by a flanged gasket (6, 7) and the protective tube is sealed against pressure and corrosion by an electrical instrumentation passage piece (9) interposed between the two flanges.

Description

i "Electrical thermometer having an instrumentation passage piece

  resistant to pressure and corrosion.

  The invention relates to an electric thermometer

  for the chemical process technique with an electric temperature sensor inserted into a

  closed, thick-walled protection at the front measuring end, made of glass and in an electrical connection box for the connecting wires of the temperature sensor.

  The requirements for tools that can be used in an explosive environment, such as

  electric thermometers require a secure separation between the electrical measuring circuit and the explosive mid-point. This is achieved for thermometers with reliable protection tubes which are made

  with sufficiently determined minimum wall thicknesses, of sufficiently non-corrosive materials, in a form resistant to pressure, temperature and

to vibrations.

  In the chemical process technique so-called glass thermometers are made for

  Corrosion resistance in a borosilicate glass with high chemical resistance. They consist of a thick-walled glass tube, tapered at the end.

  anteriority in a measuring point and closed A

  the inside of the measuring tip is arranged

temperature meter.

  The temperature sensor can be used as a platinum resistance thermometer or as a thermocouple Its electrical connection wires

  are guided through the glass tube towards the end

  open back tee of the tube and are attached to the terminals of an electrical connection box This housing is usually cemented to the rear end of the

  protective tube with a synthetic resin glue

  that to fix this thermometer on the nozzles of the chemical containers, one slides on the stem of the

  a thermometer with a glass sleeve whose integral diameter

  is significantly larger than the outer diameter

  The rear end, facing the connection box, of the sleeve

  glass, is rigidly fused with the tube of

  tection, while the anterior end is equipped

  of a flange-type glass fitting according to

  DIN I 50 3587 for attachment to the corresponding nozzle of the reaction vessels The sealing faces of the flange connection can be spherical or flat To ensure the tightness of the aggressive media in the reaction vessels vis-à-vis of the outside environment, we place between

  the sealing faces a sealing ring made of

appropriate.

  In the mounted state, the measuring tip of the heat

  meter enters the reaction medium to improve

  improve the heat transfer from the reaction medium to the temperature sensor in the

  measuring point, thermo pastes are used.

  Normally, temperatures up to 2000 ° C. and overpressures of up to 4 bar are encountered in the reaction vessels.

  pumping through the containers

  As a result, in the case of liquid media, flow rates of up to 3 m / sec are encountered. and in the case of gaseous media up to 20 m / sec. The thermometers described previously in the state of the art have despite the use of borosilicate glass with high chemical resistance, with

  significant wall thicknesses an important defect

  both in safety technology The inside of the -protection tube is indeed in direct communication _with

  the environment by the open end and by the bolt-

  connection made waterproof only in accordance

  environmental requirements In the event of a rupture of the measuring tip or the protective tube, the generally very aggressive and / or explosive reaction medium can therefore reach the environment directly. Rupture of the glass tube

  can occur, for example, by placing the tube in

  These ruptures are certainly rare, but they represent a risk that remains to be avoided.

as possible.

  It is therefore an object of the invention, to provide

  a thermometer, which under the conditions of

  mentioned, even when the

  protection tube, prevents the passage of

  act of certainty in the environment.

  This problem is solved according to the invention by an electric glass thermometer which is characterized in that the rear part of the protection tube and the connection box are connected together by a flanged joint and the glass tube is sealed against pressure and corrosion test by a

  passage piece of electrical instrumentation interpolated

between the two flanges.

  There is a very important advantage to

  the instrumentation passage piece of a collar

  integrated, which can be clamped between the normal flanges

  the instrument passage piece is supported.

  In order to improve the pressure resistance on the opposite side of the measuring sensor against the rear flange This can be achieved by the fact that the inside diameter of the rear flange is smaller than the outside diameter of the body. of the passage piece, or that the rear flange is provided with a diametrical rib to support the passage piece

instrumentation.

  For the centering of the instrumentation

  in the two flanges, it is possible to implement a centering device coming into contact with the outside face of the flange and which, in a simple manner, can

  consist of a synthetic or metal ring

  vertical, threaded externally on the piece of pas-

wise instrumentation.

  The instrumentation passage piece is corrosion-proof, when it consists of fluorocarbon resin and the electrical connection

  is provided by at least one conductive passage rod

  trice electrically directed axially, and constituted

  an anti-corrosion metal, preferably tantalum.

  Depending on the area of use, we can implement

  for the instrumentation passage piece of

  very materials, such as polyethylene or equivalent plastics, glass or ceramic for the traverse itself and tungsten, steel

  austenitic, precious metals or alloys

  proprieties for the electrical rods of passage We must choose materials, which are stable with respect to

reaction media involved.

  It has been particularly indicated that the back flange is made of an electrically nonconductive material.

  Thanks to the thermometer according to the invention,

  from a piece of instrumentation passage to the test

  pressure and corrosion, essential progress is being made with regard to the safety of

  functioning with respect to the glass thermometers

  parts from the state of the art.

  The invention will be explained in detail at

  from a concrete example of realization.

  Thus, FIG. 1 shows an overall view of the glass thermometer according to the invention, FIG. 2 shows a detail drawing of the electrical instrumentation passage piece, FIG. 3 shows the support of the passage piece of FIG. Against the small inside diameter rear flange, FIG. 4 shows the support of the instrumentation passage piece against the rear flange by a rib, FIG. 4a shows a view along the line I-VA Va of FIG. Figure 4, Figure 5 shows a passage room

  instrumentation with centering device.

Example:

  FIG. 1 shows the overview of a glass thermometer according to the invention. It consists of a glass protection tube 1 having a tapered measuring tip 2 at its front end and closed by

  fusion In the measuring tip is a thermo-

  Electrical resistance meter in platinum 3, which is embedded in a heat conductive paste to create a better thermal contact on the glass wall. The rear end of the protective tube is inserted into a thick-walled glass sleeve 4, and

  fused internally with the sleeve into

  The glass sleeve has a clear inside diameter

  larger than the outer diameter of the tube

  The two ends of the glass sleeve are made of flanged connections according to DIN ISO 3587 In addition, the flange connection 5 directed to the

  measuring tip is used with its water surface

  shape-like shape (alternatively also bowl-shaped or flat), to fix the thermometer

  the corresponding nozzles of the

  action, while the second flange connection 6 serves

  the connection of the thermometer to the flange 7 correspon-

  The flange gasket 7 is in the example considered metal The two flanges

  6 and 7 have flat sealing surfaces

  spherical or bowl-shaped sealing faces

are also possible.

  To make the inside of the thermometer

  To the external environment, the electrical instrumentation passage part composed of the passage body 9 with the integrated collar 10 and a pair of metal passage rods 11 directed are used.

  axially For reasons of resistance to corrosion

  temperature and at the temperature, the passage body with the flange is made of a fluorocarbon resin

and tantalum stems.

  The two flange connections 6 and 7 with the collar of the instrumentation passage piece located between them are held together by a standardized assembly flange 12. In the case envisaged, the

  collar also constitutes a seal.

  The connection wires 13 of the resistance thermometer pass through the protective tube from the measurement point to the rear and are electrically connected to the instrumentation passage piece.

  On the other side of the transition room

  corresponding junction electrical picks are going

  from the transit rods to the connecting

  14 in the junction box.

  FIG. 2 shows a detail drawing of the instrumentation passage piece. It consists of a passage body 9 with a shaped collar 10 and

  two electrically conductive passage rods 11.

  The collar 10 fulfills the function of sealing ring in any case necessary for the flange gaskets 6 and

  7 To optimize its sealing properties, the col-

  let is provided with a toric bead.

  In the concrete example of realization of the

  Figure 2, the collar is made at the end without prejudice.

  this of operation, the snare can naturally be placed in any place along the body

  In the same way, it is not necessary to

  to align the sealing surfaces 6 and 7 plane Spherical sealing surfaces are also

possible.

  FIG. 3 shows an embodiment of the instrumentation passage piece with a support that is particularly resistant to the pressure of the workpiece

  passage in the case of a rupture of the glass tube.

  The support is obtained by an inside diameter of the rear flange 7, smaller than the outside diameter

  of the body of the instrumentation passage piece.

  In the embodiment of the instrumentation passage piece in FIG. 4, the pressure safety support is caused by a rib 16

arranged diametrically.

  In another embodiment of the invention,

  tion according to Figure 5, the insertion part of

  tight trenching between flanges 6 and 7, is cen-

  In addition, the casing of the centering ring adapts to the shape of the outer face of the front flange 6 and

  creates the exact co-axial alignment of the

  this of instrumentation passage and flange.

Claims (9)

  1. Electric thermometer for chemical process technology with an electrical temperature sensor (3) in a thick-walled, pressure-proof glass protective tube (1), closed to   the front end and an electrical connection box   (8) for the connection wires (13) of the cap-   temperature sensor, an electric thermometer characterized   in that the rear end of the protective tube   (1) and the connection box (8) are connected   seems to be a flanged joint (6, 7) and the tube of   tection is sealed against the pressure   and corrosion by a piece of instrument passage   electrical supply (9) interposed between the two flanges.   2. Electric thermometer according to the   cation 1, characterized in that the passage piece   instrumentation (9) is provided with an integral collar (10)   which can be clamped between the flanges (6, 7).   Electric thermometer according to claim   cation 2, characterized in that the instrumentation passage piece (9) is supported by its turned face   opposite the sensor, on the rear flange (7).   4. Electric thermometer according to claim   cation 3, characterized in that the inner diameter of the rear flange (7) is smaller than the outside diameter of the same body (9) of the instrumentation passage piece.   5. Electric thermometer according to claim   cation 1, characterized in that the instrumentation passage piece (9) is clamped between the two flanges   (6, 7) and has a centering device (17)   contacting the outer face of the flange.   6. Electric thermometer according to claim   cation 5, characterized in that the central   trage consists of a ring of synthetic material or metal threaded externally on the piece of passage of instrumentation.   7. Electric thermometer according to any one   conque of claims 1 to 6, characterized in that   the instrumentation passage piece is made of a fluorocarbon resin and has at least one   electrically conducting passage rod (11), with an anti-corrosion metal.   Electric thermometer according to claim   cation 7, characterized in that the passage rod electrical (11) is in tantalum.   9. Electric thermometer according to which one   conque of claims 1 to 8, characterized in that   the rear flange (7) consists of a material electrically conductive.