DE102014102973A1

DE102014102973A1 - Pressure sensor

Info

Publication number: DE102014102973A1
Application number: DE102014102973.9A
Authority: DE
Inventors: Peter Klöfer; Anh Tuan Tham
Original assignee: Endress and Hauser SE and Co KG
Current assignee: Endress and Hauser SE and Co KG
Priority date: 2014-03-06
Filing date: 2014-03-06
Publication date: 2015-09-10
Also published as: WO2015132089A1

Abstract

It is a cost-effective producible capacitive pressure sensor, with a pressurizable and pressure-dependent elastically deformable metallic measuring membrane (1), a metallic half-shell (3) having a connected to an outer edge of a first side of the measuring membrane (1), the measuring membrane ( 1) facing the end, a below the measuring diaphragm (1) in the half-shell (3) enclosed pressure chamber (5) arranged in the half-shell (3), of the measuring diaphragm (1) spaced glass filling (11), and a capacitive electromechanical Transducer for metrological detection of a pressure-dependent deformation of the measuring diaphragm (1), with a measuring electrode (15) arranged on the glass filling (11) and a counterelectrode formed by the metallic measuring diaphragm (1), whose measuring electrode (15) is located on one of the measuring diaphragm (1) facing the end face of the glass filling (11) arranged deep-drawn part.

Description

The present invention relates to a pressure sensor, with a pressurizable and pressure-dependent elastically deformable metallic measuring membrane, a metallic half-shell having a connected to an outer edge of a first side of the measuring membrane, the measuring membrane facing end side, one below the measuring membrane in the half-shell enclosed pressure chamber, arranged in the half-shell, spaced from the measuring membrane glass filling, and a capacitive electromechanical transducer for metrological detection of a pressure-dependent deformation of the measuring membrane, with a arranged on the glass filling measuring electrode and a counter electrode formed by the metallic measuring membrane.
Pressure sensors are used in industrial measurement technology to measure pressures.
Pressure sensors regularly have a measurement membrane, which is arranged on a base body and can be pressurized and pressure-dependently elastically deformable under inclusion of a pressure chamber, and an electromechanical transducer for metrological detection of the pressure-dependent deformation of the measurement membrane.
Pressure sensors with a measurement membrane arranged on a base body including a pressure chamber can be designed as absolute pressure sensors which measure a pressure with respect to vacuum by evacuating the pressure chamber. Alternatively, they can be designed as relative pressure sensors which measure a pressure relative to one of the pressure chambers via a reference pressure, in particular the atmospheric pressure, which passes through the main body and opens into the pressure chamber. In addition, they can be designed as differential pressure sensors, which measure a pressure difference between a first and a second pressure. For this purpose, an identically constructed second base body is provided on a side facing away from the first body side of the measuring diaphragm, and the measuring diaphragm via a first through the first body leading into the first pressure chamber opening pressure supply to the first, and a second through the second body passing in the second pressure chamber opening pressure supplied to the second pressure.
With pressure sensors there is a risk that the measuring diaphragm will be exposed to overload. In this case, pressures acting on the measuring membrane can become so great that the measuring membrane can be deflected too strongly and thereby damaged.
One possible measure to protect the measuring diaphragm in the event of overloading is to provide a diaphragm bed in the pressure sensor underneath the measuring diaphragm, which supports the diaphragm in case of overload. For this purpose, the membrane bed preferably has a geometry adapted to the bending contour of the measuring membrane, on which the measuring membrane comes to rest in case of overload.
In the US 3,618,390 a differential pressure sensor is described which comprises two metallic half-shells. Between the two half-shells a metallic measuring membrane is provided, which is welded to the two half-shells. The interiors of the half-shells are filled with the release of a subdivided by the measuring diaphragm into two pressure chambers portion with glass. In this case, the sides of the glass fillings facing the measuring membrane are ground in such a way that the glass forms a concave membrane bed inside the respective half-shell, which serves to support the measuring membrane in the event of overload.
In measuring operation, a first side of the measuring diaphragm is acted upon by a first pressure transmitter filled with a pressure-transmitting liquid with a first pressure and a second side of the measuring diaphragm via a second pressure-transmitting liquid filled with a second intermediate pressure medium. Each pressure transmitter comprises a separating diaphragm which is acted upon externally by the first and the second pressure during measurement operation, and under which a pressure-receiving chamber is enclosed, which is connected to the associated pressure chamber via a pressure supply extending through the respective half-shell and its glass filling.
A capacitive electromechanical transducer is provided which metrologically detects a deformation of the metallic measuring diaphragm that is dependent on the difference between the first and the second pressure. This comprises metallic coatings applied to the concave membrane beds as electrodes, which together with the measuring membrane in each case form a capacitor. The electrical connection of the electrodes takes place in each case through a metallic tube which opens out into the respective pressure chamber and runs through the glass filling, and is led out of the half-shell via a glass feedthrough in an electrically insulated manner with respect to the respective half-shell.
Before the initial start-up, the two diaphragm seals are filled with the pressure-transmitting fluid via these tubes, and the tubes are then closed.
Both the grinding of the glass precipitations and the metallic coating of the Ground concave membrane beds represent time and cost intensive operations.
It is an object of the invention to provide a cost-producible capacitive pressure sensor.
To solve these objects, the invention comprises a pressure sensor, with

A pressure-sensitive elastically deformable metallic measuring membrane,
A metallic half-shell which has an end face connected to an outer edge of a first side of the measuring membrane and facing the measuring membrane,
A pressure chamber enclosed in the half-shell under the measuring diaphragm,
- An arranged in the half-shell, spaced from the measuring membrane glass filling, and
A capacitive electromechanical transducer for the metrological detection of a pressure-dependent deformation of the measuring diaphragm, with a measuring electrode arranged on the glass filling and a counterelectrode formed by the metallic measuring diaphragm, which is characterized in that
- The measuring electrode is arranged on one of the measuring membrane facing the end face of the glass filling deep-drawn part.

According to a preferred embodiment of the invention, the measuring electrode and the measuring membrane facing end face of the glass filling for supporting the measuring diaphragm in the event of an overload acting on a shape, which corresponds to a bending contour of the measuring diaphragm in the case of the overload acting thereon.
According to a development of the invention

An electrically conductive contact pin is provided,
The contact pin is connected to an underside of the measuring electrode facing away from the measuring diaphragm by means of an electrically conductive mechanical connection, in particular by means of spot welds,
- The contact pin passes through the glass filling, and
- Is in a remote from the measuring membrane bottom of the half-shell, a passage, esp. A glass feedthrough, provided through which extends the contact pin and electrically insulated from the half shell is contacted.

According to a development of the latter training

- The contact pin is a hollow pin, and
- The measuring electrode has a the pressure chamber with an interior of the hollow pin connecting recess.

According to a development of the last-mentioned further development of the hollow pin forms a pressure supply, via which the half-shell facing side of the measuring diaphragm can be acted upon with a pressure.
According to one embodiment of the invention, the outer edge of the measuring diaphragm is connected to an end side of the half-shell facing the measuring diaphragm by means of a pressure-tight joint, in particular a weld.
According to a further embodiment of the invention, the pressure sensor is designed as a differential pressure sensor by

A second half-shell connected to an outer edge of a second side of the measuring membrane is provided which is identical to the half-shell connected to the first side of the measuring membrane,
- In the second half-shell, a second glass filling is arranged, which is identical to the glass filling of the half-shell connected to the first side of the measuring diaphragm, and
- On the end face of the second half-shell facing the measuring diaphragm a second measuring electrode is arranged, which is identical to the measuring electrode arranged in the half-shell connected to the first side of the measuring diaphragm.

According to a development of the last-mentioned embodiment, the undersides of the two measuring electrodes facing away from the measuring diaphragm are each connected to an electrically conductive contact pin,

Passing through the glass filling of the respective half shell,
- Is electrically contacted via a arranged in a remote from the measuring membrane bottom of the respective half-shell implementation opposite the respective half-shell,
- Is designed as a hollow pin,
- The interior of which is connected via a recess in the measuring electrode connected to the respective contact pin with the adjoining the respective measuring electrode pressure chamber, and
- Over which the respective contact pin facing side of the measuring membrane can be acted upon with a pressure.

Furthermore, the invention comprises a method for producing a pressure sensor according to the invention, which is characterized in that

The one half-shell having a bore is produced in the bottom thereof,
- The measuring electrode is made by deep drawing of a metal sheet as a deep-drawn part,
The contact pin, in particular by means of one or more spot welds, is connected to the measuring electrode,
A predetermined amount of glass solder is introduced into the half shell such that the bore in the bottom of the half shell and a partial region of the interior of the half shell are filled with glass solder,
The introduced glass solder in the half shell is heated to a processing temperature above a softening point and below a melting point of the glass solder at which the glass solder forms a soft and compressible mass,
- The measuring electrode is inserted together with the associated contact pin in the soft glass solder, and
- The glass solder adapts to a shape of the measuring electrode due to the pressure exerted by the measuring membrane on the glass solder pressure.

According to a preferred embodiment of the method

- When inserting the measuring electrode by means of a punch, esp. A punch made of graphite, pressed on the soft glass solder, and
- The stamp has on the end face an area whose size and shape corresponds to the size and shape of the measuring electrode.

According to a further preferred embodiment of the method according to the invention, excess glass solder exits through the bore in the bottom of the half-shell when inserting the measuring diaphragm and the associated contact pin.
According to a development of the method according to the invention

- Has the half-shell on a sales area, and
- The measuring electrode is pressed by means of the punch so far into the soft glass solder that an outer edge of the punch rests on the shoulder surface.

According to a further embodiment of the method according to the invention

- The contact pin is a hollow pin, and
- An interior of the hollow pin is sealed before insertion into the soft glass solder by means of a pin, esp. A pencil made of graphite, and the pin is removed after cooling of the glass solder again.

The invention and its advantages will now be explained in more detail with reference to the figures of the drawing, in which three embodiments are shown. Identical elements are provided in the figures with the same reference numerals.
1 shows: an absolute pressure sensor according to the invention;
2 shows: a relative pressure sensor according to the invention;
3 shows: a differential pressure sensor according to the invention; and
4 shows an exploded view for illustrating a method for producing a pressure sensor according to the invention.
1 shows an embodiment of a pressure sensor according to the invention. This comprises a metallic measuring membrane to be acted upon during measurement operation with a pressure p to be measured 1 which elastically deforms in response to the pressure p acting thereon.
The measuring membrane 1 is on a cup-shaped metallic half-shell 3 arranged. The half shell 3 includes a floor 5 and a subsequent, preferably substantially cylindrical, the measuring membrane 1 supporting half-shell wall 7 , measuring membrane 1 and half shell 3 are by means of a pressure-tight joint 9 connected with each other. For this purpose, an outer edge of one of the half-shell 3 facing first side of the measuring diaphragm 1 with one of these side of the measuring diaphragm 1 facing annular disk-shaped end face of the half-shell wall 7 pressure-tight connected, especially welded.
One from the measuring membrane 1 spaced, to the ground 5 adjacent part of the interior of the half-shell 3 is with a glass filling 11 filled.
Under the measuring membrane 1 is in the half shell 3 a pressure chamber 13 trapped by the measuring membrane 1 and one of the measuring membrane 1 facing end of the glass filling 11 is limited.
The pressure sensor comprises a capacitive electromechanical transducer, which serves the pressure-dependent deformation of the measuring diaphragm 1 metrologically to capture.
The converter has a measuring electrode 15 and one through the metallic measuring membrane 1 formed counter electrode. measuring electrode 15 and measuring membrane 1 form a capacitor whose capacity depends on the pressure-dependent deflection the measuring membrane 1 is dependent. The pressure measurement is carried out, for example, by determining the capacitance of this capacitor by means of a capacitance measuring circuit, not shown here, and by means of a characteristic curve determined beforehand in the context of a calibration method, on the measuring diaphragm 1 is assigned to acting pressure p to be measured.
According to the invention, the measuring electrode 15 one on the measuring diaphragm 1 facing end face of the glass filling 11 arranged from a metal sheet made by deep drawing deep-drawn part. The metal sheet preferably has a thickness less than or equal to one tenth of a millimeter, and consists for. B. of a steel. Deep-drawn parts can be produced extremely cheaply in large quantities.
The front of the glass filling 11 and the measuring electrode 15 are identical in shape and preferably designed as a membrane bed, which is the measuring membrane 1 is supported in the event of an overload acting on it. For this purpose, they have a shape that the bending contour of the measuring membrane 1 in the event of an overload acting on it. The measuring membrane 1 thus comes in the event of an overload acting on the measuring electrode 15 and the front of the glass filling 11 to support, and is supported by this. The pressure sensor is thus overload resistant.
For electrical connection of the measuring electrode 15 to a, not shown here, the capacitance measuring circuit comprehensive measuring electronics is an electrically conductive contact pin 17 intended. This is one of the measuring membrane 1 opposite underside of the measuring electrode 15 connected by means of an electrically conductive mechanical connection, and passes through the glass filling 11 therethrough. The connection consists for example of one or more of the measuring membrane 1 with the contact pin 17 electrically and mechanically connecting welding points.
In the ground 5 the half shell 3 is an implementation 19 provided by the contact pin 17 leads through, and over which the contact pin 17 electrically isolated from the half shell 3 is contactable. The implementation 19 is preferably a glass feedthrough. For this, the ground points 5 a through hole 21 on, through which the contact pin 17 leads through. One between an inner wall of the bore 21 and the contact pin 17 existing annular cylindrical cavity is with a filling 23 made of glass.
The pressure sensor according to the invention can - as in 1 illustrated - be designed as absolute pressure sensor which measures the pressure to be measured p absolute, against a vacuum. In that case the contact pin is 17 a solid pin, and the one under the measuring diaphragm 1 enclosed pressure chamber 13 is evacuated.
Alternatively, the pressure sensor according to the invention may be formed as a relative pressure sensor, the pressure to be measured p relative to a reference pressure p _ref , z. B. the atmospheric pressure, measures. A preferred embodiment of this is in 2 shown. The in 2 shown relative pressure sensor differs from that in 1 shown absolute pressure sensor in that instead of the solid contact pin 17 a trained as a hollow pin contact pin 25 is provided, and the measuring electrode 15 one the interior of the pressure chamber 13 with the interior of the hollow pin connecting recess 27 having. The trained as a hollow pin pin 25 forms a pressure supply over which the half shell 3 facing first side of the measuring diaphragm 1 with a pressure - here the reference pressure p _ref - can be acted upon. The reference pressure p _ref becomes the pressure measuring chamber 13 via the same time the electrical connection of the measuring electrode 1 causing contact pin 25 fed. A separate associated with additional manufacturing cost and additional manufacturing costs reference pressure supply is not required.
Alternatively, the pressure sensor according to the invention may be designed as a differential pressure sensor which measures a pressure difference Δp between a first pressure p ₁ and a second pressure p ₂ . An embodiment of this is in 3 shown. The differential pressure sensor differs from that in 2 represented relative pressure sensor characterized in that on the second side of the measuring diaphragm 1 a second metallic half shell 3 is provided, which is identical to that with the first side of the measuring diaphragm 1 connected half shell 3 is. The measuring membrane 1 facing end side of the second half-shell 3 is with an outer edge of the second side of the measuring diaphragm 1 by means of a pressure-tight joint 9 connected, especially welded. In the second half shell 3 is a glass filling 11 and one with a preferably designed as a hollow pin contact pin 25 connected second measuring electrode 15 intended. The contact pin 25 is also here through an implementation 19 in the ground 5 the second half shell 3 electrically isolated from the second half shell 3 contactable. glass panel 11 , Contact pin 25 , Measuring electrode 15 and implementation 19 the second half shell 3 are identical to the corresponding ones in the first half shell 3 provided elements, so that the differential pressure sensor relative to the measuring diaphragm 1 is constructed symmetrically overall.
The contact pins 25 are here also preferably formed as hollow pins, which also serve as a pressure supply, on the measuring operation in the first side of the measuring membrane 1 with the first pressure p ₁ and the second side of the measuring diaphragm 1 with the second pressure p _{2 is} applied. In this case, the first and the second pressure p ₁ , p ₂ respectively over the interior of the respective hollow pin and the recess 27 in the respective measuring electrode 15 the respective pressure chamber 13 fed.
The pressure sensors according to the invention have the advantage that they can be produced inexpensively in a simple manner. Thereby the measuring electrodes become 1 prefabricated as a deep-drawn part, and each connected to the desired type of contact pin via an electrically conductive mechanical connection, esp. By means of one or more spot welds, to form a module. For the production of absolute pressure sensors this massive contact pins 17 , For the production of relative or differential pressure sensors preferably designed as a hollow pin contact pins 25 used.
The half-shells 3 are preferably prefabricated just like the modules in large numbers and therefore cost.
Below is in each metallic half shell 3 a predetermined amount of glass solder 29 inserted so that the bore 21 in the ground 5 the respective half shell 3 and a portion of the interior of the respective half-shell 3 completely with glass solder 29 is filled. This state is in the exploded view illustrating the manufacturing method in FIG 4 shown. The predetermined amount is at least equal, preferably slightly larger than the total for the glass filling 11 and the filling 23 the glass passage 19 required quantity.
Subsequently, the introduced glass solder 29 in the half shell 3 heated to above the softening point and below the melting point processing temperature at which the glass solder 29 forming a soft, compressible mass. Subsequently, the measuring electrode 15 together with the associated contact pin 17 respectively. 25 in the soft glass solder 29 used. For this purpose, preferably a stamp 31 used by the measuring electrode 15 in the in 4 indicated by arrows on the soft glass solder 29 is pressed. The contact pin penetrates 17 respectively. 25 the glass solder 29 at least so far that its free end after pressing centrally through the hole 21 passes through. The Stamp 31 is preferably made of graphite or other material that does not bond with glass. The Stamp 31 has on its front side an area 33 the size and shape of the size and shape of the measuring electrode 15 equivalent. This will cause the measuring electrode 15 when inserting into the glass solder 29 flat supported, and is thus protected from deformation. Due to the insertion of the measuring electrode 15 on the glass solder 29 applied pressure, the soft glass solder fits 29 to the shape of the measuring electrode 15 on, and receives in this way the bending contour of the measuring diaphragm 1 in the case of an overload acting on it appropriate shaping. During the depression can excess glass solder 29 through the hole 21 in the ground 5 the half shell 3 escape.
The after insertion of measuring electrode 15 and contact pin 17 respectively. 25 again cooled glass solder 29 forms the glass filling 11 and the filling 23 the glass passage 19 ,
Preferably, the half shells 3 one in the finished pressure sensor from the measuring diaphragm 1 spaced, the glass filling 11 enclosing on the outside, and flush with the glass filling 11 final sales area 35 on, and the stamp 31 is with a measuring electrode shaped area 33 outside surrounding outer edge 37 fitted. The measuring electrode 15 is by means of the stamp 31 so far into the soft glass solder 29 pressed into it, that the edge 37 of the stamp 31 on the sales area 35 rests. The sales area 35 thus forms a defined stop for the stamp 31 , This ensures that the measuring electrode 15 in the finished pressure sensor a defined and reproducible manufacturable distance to the measuring diaphragm 1 having.
In the manufacture of pressure sensors designed as a hollow pin contact pins 25 , the interiors of the hollow pins are before insertion into the soft glass solder 29 sealed to prevent penetration of glass solder 29 to prevent the interior. For this purpose, preferably a pin 39 in the interior of the contact pin 25 used after cooling the glass solder 29 is removed again. For this purpose, there is the pen 39 graphite or another with the metal of the contact pin 25 no connection incoming material.
The inventive method has the advantage that both the glass filling 11 as well as the glazing of the contact pin 17 respectively. 25 be generated in a single operation. In this operation, at the same time also the membrane bed forming, preferably the bending contour of the measuring membrane 1 corresponding shaping of the measuring membrane 1 facing end face of the glass filling 11 generated.
LIST OF REFERENCE NUMBERS

1: measuring membrane
3: half shell
5: ground
7: Half shell wall
9: coincidence
11: glass panel
13: pressure chamber
15: measuring electrode
17: pin
19: execution
21: drilling
23: Filling of glass
25: pin
27: recess
29: glass solder
31: stamp
33: Area
35: shoulder surface
37: edge
39: pen

QUOTES INCLUDE IN THE DESCRIPTION
This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.
Cited patent literature

US 3618390 [0007]

Claims

Pressure sensor, with - a pressure-sensitive and pressure-dependent elastically deformable metallic measuring diaphragm ( 1 ), - a metallic half shell ( 3 ), one with an outer edge of a first side of the measuring diaphragm ( 1 ), the measuring membrane ( 1 ) facing end face, - one under the measuring diaphragm ( 1 ) in the half shell ( 3 ) enclosed pressure chamber ( 5 ), - one in the half shell ( 3 ), from the measuring membrane ( 1 ) spaced glass filling ( 11 ), and - a capacitive electromechanical transducer for metrological detection of a pressure-dependent deformation of the measuring diaphragm ( 1 ), with one on the glass filling ( 11 ) arranged measuring electrode ( 15 ) and one through the metallic measuring membrane ( 1 ) formed counter electrode, which is characterized in that - the measuring electrode ( 15 ) on one of the measuring membrane ( 1 ) facing end face of the glass filling ( 11 ) arranged deep-drawn part is.
Pressure sensor according to claim 1, characterized in that the measuring electrode ( 15 ) and the measuring membrane ( 1 ) facing end of the glass filling ( 11 ) for supporting the measuring membrane ( 1 ) have, in the case of an overload acting thereon, a shaping which corresponds to a bending contour of the measuring diaphragm ( 1 ) in the case of the overload acting thereon.
Pressure sensor according to claim 1, characterized in that - an electrically conductive contact pin ( 17 . 25 ), - the contact pin ( 17 . 25 ) with one of the measuring membrane ( 1 ) facing away from the underside of the measuring electrode ( 15 ) is connected by means of an electrically conductive mechanical connection, esp. By means of welding points, - the contact pin ( 17 . 25 ) through the glass filling ( 11 ), and - in one of the measuring membrane ( 1 ) facing away from the ground ( 5 ) of the half shell ( 3 ) an implementation ( 19 ), esp. A glass feedthrough is provided, through which the contact pin ( 17 . 25 ) and electrically isolated from the half-shell ( 3 ) is contactable.
Pressure sensor according to claim 3, characterized in that - the contact pin ( 25 ) is a hollow pin, and - the measuring electrode ( 15 ) a pressure chamber ( 5 ) with an interior of the hollow pin connecting recess ( 27 ) having.
Pressure sensor according to claim 4, characterized in that the hollow pin forms a pressure supply, via which the half-shell ( 3 ) facing side of the measuring membrane ( 1 ) can be acted upon with a pressure.
Pressure sensor according to one of the preceding claims, characterized in that the outer edge of the measuring diaphragm ( 1 ) with one of the measuring membrane ( 1 ) facing end side of the half-shell ( 3 ) by means of a pressure-tight joint ( 9 ), esp. A weld, is connected.
Pressure sensor according to one of the preceding claims, characterized in that it is designed as a differential pressure sensor by - one with an outer edge of a second side of the measuring diaphragm ( 1 ) connected second half-shell ( 3 ) identical to that with the first side of the measuring diaphragm ( 1 ) connected half shell ( 3 ), - in the second half-shell ( 3 ) a second glass filling ( 11 ), which are identical to the glass filling ( 11 ) with the first side of the measuring membrane ( 1 ) connected half shell ( 3 ), and - on the measuring membrane ( 1 ) facing end side of the second half-shell ( 3 ) a second measuring electrode ( 15 ) identical to that in the first side of the measuring membrane ( 1 ) connected half shell ( 3 ) arranged measuring electrode ( 15 ).
Pressure sensor according to claim 7, characterized in that the of the measuring membrane ( 1 ) facing away undersides of the two measuring electrodes ( 15 ) each with an electrically conductive contact pin ( 25 ), - through the glass filling ( 11 ) of the respective half shell ( 3 ) passes through, - via a in one of the measuring membrane ( 1 ) facing away from the ground ( 5 ) of the respective half shell ( 3 ) ( 19 ) electrically isolated from the respective half-shell ( 3 ) is contactable, - is formed as a hollow pin, - whose interior via a recess ( 27 ) in the with the respective contact pin ( 25 ) connected measuring electrode ( 15 ) with the to the respective measuring electrode ( 15 ) adjacent pressure chamber ( 13 ), and - via which the respective contact pin ( 25 ) facing side of the measuring membrane ( 1 ) With a pressure (p ₁ , p ₂ ) can be acted upon.
Method for producing a pressure sensor according to one of the preceding claims, characterized in that - the one bore ( 21 ) in their soil ( 5 ) having half shell ( 3 ) is manufactured, - the measuring electrode ( 15 ) is made by deep drawing from a metal sheet as a deep-drawn part, - the contact pin ( 17 . 25 ), in particular by means of one or more spot welds, with the measuring electrode ( 15 ), - a predetermined amount of glass solder ( 29 ) into the half-shell ( 3 ) is introduced, that the bore ( 21 ) in the ground ( 5 ) of the half shell ( 3 ) and a portion of the interior of the half-shell ( 3 ) with glass solder ( 29 ), - the introduced glass solder ( 29 ) in the half shell ( 3 ) to above a softening point and below a melting point of the glass solder ( 29 ) is heated at which the glass solder ( 29 ) forms a soft and compressible mass, - the measuring electrode ( 15 ) together with the associated contact pin ( 17 . 25 ) into the soft glass solder ( 29 ), and - the glass solder ( 29 ) due to the fact of the measuring membrane ( 15 ) on the glass solder ( 29 ) applied pressure to a shape of the measuring electrode ( 15 ) adapts.
Method according to claim 9, characterized in that - the measuring electrode ( 15 ) when inserted by means of a punch ( 31 ), in particular a stamp ( 31 ) of graphite, on the soft glass solder ( 29 ), and - the stamp ( 31 ) on its front side an area ( 33 ), the size and shape of the size and shape of the measuring electrode ( 15 ) corresponds.
Process according to claim 9, characterized in that excess glass solder ( 29 ) when inserting the measuring membrane ( 15 ) and the associated contact pin ( 17 . 25 ) through the hole ( 21 ) in the ground ( 5 ) of the half shell ( 3 ) exit.
Method according to claim 9, characterized in that - the half-shell ( 3 ) a sales area ( 31 ), and - the measuring electrode ( 15 ) by means of the stamp ( 31 ) so far into the soft glass solder ( 29 ) is pressed, that an outer edge ( 37 ) of the stamp ( 31 ) on the sales area ( 35 ) rests.
Method according to claim 9, 10, 11 or 12, characterized in that - the contact pin ( 25 ) is a hollow pin, and - an interior of the hollow pin before insertion into the soft glass solder ( 29 ) by means of a pencil ( 39 ), esp. of a pen ( 39 ) of graphite, is closed, and the pen ( 39 ) after cooling the glass solder ( 29 ) is removed again.