DE102021112181A1 - Sealing device for a sensor for detecting a leak and sensor with a sealing device - Google Patents

Abstract

The invention relates to a sealing device (20) for a sensor (1) for detecting a leak, comprising:
- a seal (21) which is suitable for being arranged in a sensor (1), the seal (21) having at least one sealing edge (22) which is suitable for being connected to at least one sensor wall (10, 12 ) to get in touch
- a base body (23) which is suitable for coming into contact with the at least one sensor wall (10, 12) to be sealed,
wherein the base body (23) has a cavity (24) which is designed in such a way that the cavity (24) can be covered by the sensor wall (10, 12) to be sealed,
- at least one first conductor track, which is arranged in the cavity (24),
- at least one second conductor track, which is arranged in the cavity (24),
or, if the sensor wall (10, 12) is electrically conductive, the second conductor track is arranged in such a way as to come into electrical contact with the sensor wall (10, 12) to be sealed.

Description

The invention relates to a sealing device for a sensor for detecting a leak and a sensor with a sealing device.

In analytical measurement technology, especially in the field of water management, environmental analysis, in the industrial sector, e.g. in food technology, biotechnology and pharmacy, as well as for a wide variety of laboratory applications, measured variables such as the pH value, conductivity or the concentration of analytes are such as ions or dissolved gases in a gaseous or liquid measuring medium is of great importance. These measured variables can be recorded and/or monitored, for example, by means of electrochemical sensors, such as optical, potentiometric, amperometric sensors, or also conductive conductivity sensors.

If a sensor is arranged in a process wall in such a way that it is in contact with the process medium, the installation point of the sensor represents a potential leakage point in the process wall. A leaking of the process medium through a damaged sensor should be avoided in any case. Immediate detection of a damaged sensor is therefore of the utmost importance.

If sensors are used in food and beverage applications, these sensors must meet the requirements of hygienic design, for example criteria of 3-A and EHEDG. This also includes leak detection.

However, manually checking the tightness of all sensors used in a production plant is very time-consuming. In addition, with a large number of sensors to be checked, it can easily happen that a sensor is overlooked during the manual check.

It is therefore an object of the invention to provide a device which makes it possible to detect a damaged sensor reliably and quickly.

This object is achieved according to the invention by the sealing device according to claim 1.

• - eine Dichtung, welche dazu geeignet ist, in einem Sensor angeordnet zu werden, wobei die Dichtung mindestens einen Dichtrand aufweist, welcher dazu geeignet ist, mit mindestens einer abzudichtenden Sensorwand in Kontakt zu kommen,
• - einen Grundkörper, welcher dazu geeignet ist, mit der mindestens einen abzudichtenden Sensorwand in Kontakt zu kommen,

wobei der Grundkörper einen Hohlraum aufweist, welcher derart ausgebildet ist, dass der Hohlraum von der abzudichtenden Sensorwand abdeckbar ist,

• - mindestens eine erste Leiterbahn, welche im Hohlraum angeordnet ist,
• - mindestens eine zweite Leiterbahn, welche im Hohlraum angeordnet ist,

oder, wenn die Sensorwand elektrisch leitfähig ist, die zweite Leiterbahn derart angeordnet ist, um mit der abzudichtenden Sensorwand in elektrischen Kontakt zu kommen,

• - eine Steuereinheit welche mit der ersten Leiterbahn und mit der zweiten Leiterbahn elektrisch verbunden ist, und dazu geeignet ist, einen elektrischen Stromfluss zwischen der ersten Leiterbahn und der zweiten Leiterbahn zu detektieren.

The sealing device according to the invention for a sensor for detecting a leak comprises:

• - a seal which is suitable for being arranged in a sensor, the seal having at least one sealing edge which is suitable for coming into contact with at least one sensor wall to be sealed,
• - a base body which is suitable for coming into contact with the at least one sensor wall to be sealed,

wherein the base body has a cavity which is designed in such a way that the cavity can be covered by the sensor wall to be sealed,

• - at least one first conductor track, which is arranged in the cavity,
• - at least one second conductor track, which is arranged in the cavity,

or, if the sensor wall is electrically conductive, the second conductor track is arranged in such a way that it comes into electrical contact with the sensor wall to be sealed,

• - A control unit which is electrically connected to the first conductor track and to the second conductor track and is suitable for detecting an electric current flow between the first conductor track and the second conductor track.

The sealing device according to the invention makes it possible for all possible leakage paths to lead through the cavity, so that a measurement medium is suitable for penetrating the cavity and making contact with the conductor tracks directly or indirectly via an electrode to which a conductor track is connected get. This means that a leak can be detected directly in the sensor, even directly behind the sensor seal. This efficiently and reliably prevents the measurement medium from escaping through the sensor.

According to one embodiment of the invention, a contact element is arranged in the cavity. The contact element is suitable for dissolving in the liquid upon contact with a liquid and for increasing the electrical conductivity of the liquid.

According to one embodiment of the invention, the contact element is a soluble salt, a soluble saline powder, a soluble saline granulate or a soluble saline molded part.

According to one embodiment of the invention, the first conductor track and/or the second conductor track comprises a metal wire or an injection-molded circuit carrier with conductor tracks, or another electrically conductive material.

According to one embodiment of the invention, the cavity comprises a first channel which extends along an outer wall of the sensor wall.

According to an embodiment of the invention, the cavity comprises a second channel which extends along an inner wall of the sensor wall.

According to one embodiment of the invention, the cavity comprises a first channel, which extends along an outer wall of the sensor wall, and comprises a second channel, which extends along an inner wall of the sensor wall, and comprises at least a third channel, which the first channel and the second channel connects.

The above object is also achieved by a sensor according to claim 8.

• - eine Sensorwand,
• - eine erfindungsgemäße Dichtvorrichtung.

The sensor according to the invention includes

• - a sensor wall,
• - A sealing device according to the invention.

According to one embodiment of the invention, the sensor wall is electrically conductive and the second conductor track is electrically connected to the sensor wall.

According to an embodiment of the invention, the sensor wall is electrically insulating and the second conductor track is arranged in the cavity at a predetermined distance from the first conductor track.

• - 1: eine Schnittdarstellung einer Ausführungsform eines Sensors mit der erfindungsgemäßen Dichtvorrichtung,
• - 2: eine detaillierte Schnittdarstellung der in 1 dargestellten Dichtvorrichtung,
• - 3: eine schematische Schnittdarstellung der in 2 gezeigten Dichtvorrichtung,
• - 4: eine alternative Ausführungsform der erfindungsgemäßen Dichtvorrichtung,
• - 5: eine weitere Ausführungsform eines Sensors mit einer Ausführungsform der erfindungsgemäßen Dichtvorrichtung,
• - 6: eine schematische Schnittdarstellung einer Ausführungsform der erfindungsgemäßen Dichtvorrichtung.

The invention is explained in more detail with reference to the following description of the figures. Show it:

• - 1 : a sectional view of an embodiment of a sensor with the sealing device according to the invention,
• - 2 : a detailed sectional view of the in 1 shown sealing device,
• - 3 : a schematic sectional view of the in 2 shown sealing device,
• - 4 : an alternative embodiment of the sealing device according to the invention,
• - 5 : a further embodiment of a sensor with an embodiment of the sealing device according to the invention,
• - 6 : a schematic sectional view of an embodiment of the sealing device according to the invention.

1 1 shows an embodiment of a sensor 1, strictly speaking a conductive conductivity sensor, with a sealing device 20 according to the invention. The conductive conductivity sensor has a first electrode 13 and a second electrode 14, which are suitable for determining the conductivity of a measurement medium.

However, the sealing device 20 according to the invention is suitable not only for use in conductive conductivity sensors, but also for use in other sensors, such as electrochemical sensors or similar sensors. 5 shows, for example, a schematically illustrated pH sensor with the sealing device 20 according to the invention.

As in 2 shown in detail, the sealing device 20 has a seal 21 , a base body 23 , at least one first conductor track 31 , at least one second conductor track 32 and a control unit 30 . The conductor tracks and the control unit 30 are part of the sensor electronics of the sensor 1, 1' or the sealing device 20.

The sensor 1,1' extends, for example, along an axis X, with the measuring medium in 1 is arranged on the outside of the sensor and sensor electronics, ie the control unit 30 and the conductor tracks 31, 32, are arranged on the inside of the sensor.

The seal 21 separates in 1 the measuring medium from the sensor electronics. The seal 21 extends, for example, transversely, i.e. perpendicularly, to the axis X. The seal 21 thus seals in 1 the outside of the sensor from the inside of the sensor. Of course, the seal 21 can also seal off other media. As in 5 As shown, the seal 21 can also seal an electrolyte from the sensor electronics, for example. The term sensor outside therefore refers to a part of the sensor 1, 1' that is to be sealed and not necessarily to the measuring environment of the sensor 1, 1' in which the measuring medium is located. Likewise, the term sensor inside refers to the part of the sensor 1, 1' to be sealed and not necessarily to all areas inside the sensor 1, 1'.

The seal 21 has a sealing edge 22 which is suitable for coming into contact with at least one sensor wall 10, 10', 11, 12 of the sensor 1, 1' to be sealed.

1 and 2 show an embodiment in which the sealing edge 22 comes into contact with an outer wall 11 and an inner wall 12 of the sensor wall 10, 10'. The sealing edge 22 extends along the sensor wall 10, 10', 11, 12 in such a way that all possible leakage paths between the outside of the sensor, ie for example the medium to be measured, are blocked and the inside of the sensor, i.e. the inside of the sensor, are sealed.

The sealing edge 22 preferably runs around the axis X. The seal 21 is made, for example, of rubber or another elastic material, for example an elastomer, which is suitable for sealing between the measured medium in the intended area of application of the sensor 1, 1' despite temperature fluctuations or the electrolyte and the inside of the sensor.

The sensor wall 10, 10', 11, 12 is in the 1 example shown by the first electrode 13 and second electrode 14 realized. However, the sensor wall 10, 11 can also, for example, be covered by a glass wall, as in the case of FIG 5 illustrated pH sensor, be realized.

The base body 23 is suitable for coming into contact with the at least one sensor wall 10, 10', 11, 12 to be sealed. The base body 23 is made of plastic or another insulating material, for example. The base body 23 is preferably in contact with at least one sensor wall 10, 10', 11, 12.

The base body 23 has a cavity 24 . The cavity 24 is designed in such a way that the cavity 24 can be covered by the sensor wall 10, 10′, 11, 12 to be sealed. In other words, the cavity 24 opens onto the sensor wall 10, 10', 11, 12. The cavity 24 extends, for example, in such a way that all possible leakage paths between the measurement medium and the sensor electronics lead through the cavity 24. Cavity 24 preferably extends transversely or perpendicularly to axis X. Cavity 24 extends, for example, along sensor wall 10, 10′, 11, 12, encircling axis X. The cavity 24 has a shape concentric about the X axis, for example.

the 3 until 6 show a cavity 24 which has a channel shape running around the axis X. Cavity 24 is preferably located near seal 21 . For example, the cavity 24 is arranged separated from the seal 21 by the base body 23 by only a few millimeters. If the seal 21 is pressure-stable, the cavity 24 can also be covered by the seal 21 , ie it can extend up to the seal 21 .

3 shows an embodiment of the cavity 24, in which the cavity 24 comprises an annular first channel 25, which runs along the first electrode 13, i.e. the outer wall 11, and a second channel 26, which runs along the second electrode 14, i.e. the inner wall 12 runs, and includes a plurality of third channels 27 which connect the first channel 25 to the second channel 26.

in the in 4 illustrated embodiment, the cavity 24 has only the first channel 25 and the second channel 26 described above.

in the in 5 and 6 illustrated embodiment, the cavity 24 has only the first channel 25 described above.

At least one first conductor track 31 is arranged in cavity 24 in all of the embodiments. 3 represents this case. If only a first conductor track 31 is arranged in the cavity 24, the second conductor track 32 must be in electrical contact with the sensor wall 10, 10 ', 11, 12, so that a current flow between the first conductor track 31 and the second conductor track 32 is possible. In this case, the sensor wall 10, 10', 11, 12 must of course be made of an electrically conductive material. in the in 3 illustrated embodiment, the second conductor track 32 is electrically connected to the first electrode 13, i.e. the outer wall 11, as also in FIG 2 to see.

If an electrically conductive liquid penetrates through the seal 21 into the cavity 24, an electrical contact between the conductor tracks 31, 32 is closed.

The first conductive line 31 and the second conductive line 32 are electrically connected to the control unit 30 (see FIG 2 ). The control unit 30 is suitable for recognizing an electrical contact closure between the conductor tracks.

4 12 shows an embodiment in which the first conductive line 31 and the second conductive line 32 are arranged in the first channel 25 of the cavity 24 . Furthermore, a third conductor track 33 and a fourth conductor track 34 are arranged in the second channel 26 in this embodiment. This makes it possible to use the control unit 30 to detect whether the seal 21 is leaking in an outside area, ie on the outside wall 11 or in an inside area, ie on the inside wall 12 .

5 shows an embodiment, here a pH sensor, in which the two conductor tracks 31, 32 next to each other at a certain distance, for example between 0.5 mm and 10 mm, preferably 1 mm, in a sensor wall 10 of the sensor 1 'along running Cavity 24 are arranged. An advantage of this embodiment is that the short-circuit path is very short here due to the small distance between the conductor tracks, which leads to a detection of the leakage even with small ingress amounts of liquid.

In 6 , also a pH sensor, similar to in 5 , the two conductor tracks 31, 32 are arranged opposite one another in a cavity 24 surrounding the sensor 1'.

Because the embodiments of 5 and 6 relate to a pH sensor with a glass wall as the sensor wall 10, of course, two conductor tracks 31, 32 must always be arranged in the cavity 24 in order to detect a penetrating liquid.

If the sensor 1, 1' is used in measurement media which include non-conductive liquids, or non-conductive liquids are separated from the sensor electronics by the seal 21, a contact element 40 can also be arranged in the cavity 24 (see Fig 2 until 4 ).

The contact element 40 is suitable for dissolving in the liquid upon contact with a liquid and for enriching the liquid with ions, for example. The contact element 40 is therefore suitable for increasing the electrical conductivity of the liquid, ie the medium which penetrates into the cavity 24 in the event of a leak in the seal 21 . The contact element 40 is, for example, a soluble salt, a soluble saline powder, soluble saline granules or a soluble saline molded part. The contact element 40 includes, for example, NaCl or KCl. The contact element 40 ensures that the control unit 30 also detects this leakage quickly and reliably if a liquid, for example ultrapure water, penetrates.

The control unit 30 is suitable for generating a message, for example a warning signal or the like, when it detects a short circuit between the conductor tracks 31, 32, 33, 34, i.e. when a liquid penetrates into the cavity 24, and sends it to a control center or a reporting unit , which is attached, for example, in the sensor 1,1', for example an LED, display or loudspeaker.
The short circuit can be, for example, between the first conductor track 31 and the second conductor track 32 and/or between the third conductor track 33 and the fourth conductor track 34, or between a conductor track arranged in the cavity 24 and an electrode 13, 14 to which one of the conductor tracks is connected is, occur. All combinations of short circuits between the various conductor tracks and/or electrodes that are possible for a person skilled in the art are suitable for detecting a short circuit by means of the conductor tracks and/or the electrodes.

Of course, it is also conceivable to design the base body 23 in two parts, with the two parts of the base body 23 being complementary and together forming the cavity 24 .

The conductor tracks 31, 32, 33, 34 can be produced using any means known to those skilled in the art. According to one embodiment, the conductor tracks 31, 32, 33, 34 are made, for example, from metal wires, for example from copper, silver, gold or platinum. According to one embodiment, the conductor tracks 31, 32, 33, 34 are produced by means of MID (Molded Interconnect Devices), for example laser structuring, laser activation, two-component injection molding. According to one embodiment, the conductor tracks 31, 32, 33, 34 are overmolded as a metallic insert. According to one embodiment, the conductor tracks 31, 32, 33, 34 are made of an electrically conductive material, for example an electrically conductive plastic. According to one embodiment, the conductor tracks 31, 32, 33, 34 are produced as an injection-molded circuit carrier with conductor tracks. According to one embodiment, the conductor tracks 31, 32, 33, 34 and/or the base body 23 are produced, for example, using a 3D printing process. According to one embodiment, the base body 23 is also injection molded, for example, or is produced by means of a machining process.

The cavity 23 can be filled with a gas or provided with a vacuum in order to prevent condensation of moisture in the cavity 24, for example.

Reference List

1.1'

sensor

10, 10'

sensor wall

11

outer wall

12

inner wall

13

first electrode

14

second electrode

20

sealing device

21

poetry

22

sealing edge

23

body

24

cavity

25

first channel

26

second channel

27

third channel

30

control unit

31

first track

32

second track

33

third track

34

fourth track

40

contact element

Claims (10)

Sealing device (20) for a sensor (1, 1') for detecting a leak, comprising: - a seal (21) which is suitable for being arranged in a sensor (1, 1'), the seal (21) having at least one sealing edge (22) which is suitable for being sealed with at least one sensor wall ( 10, 10', 11, 12) to get in touch, - a base body (23) which is suitable for coming into contact with the at least one sensor wall (10, 10', 11, 12) to be sealed, the base body (23) having a cavity (24) which is designed in this way that the cavity (24) can be covered by the sensor wall (10, 10', 11, 12) to be sealed, - at least one first conductor track (31), which is arranged in the cavity (24), - At least one second conductor track (32), which is arranged in the cavity (24), or if the sensor wall (10, 10 ', 11, 12) is electrically conductive, the second conductor track (32) is arranged in such a way to with the come into electrical contact with the sensor wall (10, 10', 11, 12) to be sealed, - A control unit (30) which is electrically connected to the first conductor track (31) and to the second conductor track (32) and is suitable for detecting an electrical current flow between the first conductor track (31) and the second conductor track (32). . Sealing device (20) according to claim 1 , A contact element (40) being arranged in the cavity (24), the contact element (40) being suitable for dissolving on contact with a liquid in the liquid and for increasing the electrical conductivity of the liquid. Sealing device (20) according to claim 2 , wherein the contact element (40) is a soluble salt, a soluble saline powder, a soluble saline granulate or a soluble saline molded part. Sealing device (20) according to one of the preceding claims, wherein the first conductor track (31) and/or the second conductor track (32) comprises a metal wire or an injection-molded circuit carrier with conductor tracks, or another electrically conductive material. Sealing device (20) according to one of the preceding claims, wherein the cavity (24) comprises a first channel (25) which extends along an outer wall (11) of the sensor wall (10). Sealing device (20) according to one of the preceding claims, wherein the cavity (24) comprises a second channel (26) which extends along an inner wall (12) of the sensor wall (10'). Sealing device (20) according to any one of the preceding claims, wherein the cavity (24) comprises a first channel (25) which extends along an outer wall (11) of the sensor wall (10) and a second channel (26) which along an inner wall (12) of the sensor wall (10'), and comprises at least one third channel (27) which connects the first channel (25) and the second channel (26) to one another. Sensor (1, 1') comprising, - a sensor wall (10, 10', 11, 12), - A sealing device (20) according to any one of the preceding claims. Sensor (1, 1 ') according to claim 8 , wherein the sensor wall (10, 10', 11, 12) is electrically conductive and the second conductor track (32) is electrically connected to the sensor wall (10, 10', 11, 12). Sensor (1, 1 ') according to claim 8 , wherein the sensor wall (10, 10', 11, 12) is electrically insulating and the second conductor track (32) is arranged in the cavity (24) from the first conductor track (31) at a predetermined distance.

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