Field device

Abstract

The invention relates to a field device (1) of process and automation technology for determining and / or monitoring a process variable. A housing (2) comprises two chambers (3), which are separated from one another by a partition (4) and in each of which an associated electronic unit (5) is disposed. The partition (4) has a through-hole (40) having a constant inside diameter, through which a contact component (6) for contacting the electronic units (5) extends. The contact component (6) has a sealing element (61), which is pressed into the through-hole (40) in such a way that the sealing element is under a mechanical preload in the through-hole (40) and seals the through-hole (40).

Description

[0001] field device

[0002] The invention relates to a field device in process and automation technology for determining and / or monitoring at least one process variable. The process variable is, for example, the temperature, the pressure in a process chamber, or the fill level, viscosity, flow rate, or density of a medium. The medium is, for example, a gas, a liquid, or a bulk solid.

[0003] Field devices are used to determine or monitor process variables. In some cases, it may be necessary to install at least parts of the sensor system in a process chamber. This may then require the field device's housing to be designed to meet the requirements for a specific type of ignition protection.

[0004] EP 0 775 292 B1 describes a housing with two chambers and a partition. The partition has an opening through which electrical contacts embedded in a potting compound extend. US 2018 / 372522 A1 shows a field device with a housing and two chambers separated from each other by a partition. The partition has a through-hole and a sleeve that can be potted. It is thus known to pot a feedthrough in a partition. However, this can be complex to manufacture. DE 10 2005 059662 A1 also discloses a housing with two sub-chambers for a field device. DE 10 2014 100 492 A1 shows a feedthrough of a component into a housing. For this purpose, a narrowing recess is provided in the wall of the housing. A clamping arrangement exerts an axial force on a sealing body against the constriction.

[0005] Therefore, the object underlying the invention is to propose a field device with a two-chamber housing which is characterized by simplified production.

[0006] The invention solves the problem by a field device in process and automation technology for determining and / or monitoring at least one process variable, with at least one housing, wherein the housing has at least two chambers separated from one another by a partition wall, wherein an electronic unit is arranged in each of the two chambers, wherein the partition wall has at least one passage having a substantially constant inner diameter, wherein at least one contact component for contacting the electronic units projects through the passage, wherein the contact component has a - preferably electrically insulating - sealing element, and wherein the sealing element is pressed into the passage in such a way that the sealing element is under mechanical prestress in the passage and alone closes the passage.

[0007] The housing of the field device according to the invention has at least two chambers which are separated from each other by a partition wall and connected to each other by the passage and the contact component.

[0008] In one embodiment, the passage is created by a bore in the partition. In an alternative embodiment, the partition is created by a continuous opening. The passage has a substantially constant inner diameter. There are therefore no constrictions or widenings. The passage can therefore also be described as continuously cylindrical. In one embodiment, the partition is an integral part of the housing; in an alternative embodiment, it is a separate component that is permanently incorporated into the interior of the housing.

[0009] The contact component is used to contact the electronic units located in the separate chambers. The contact component has a sealing element that is pressed into the passage and thus completely closes it on its own - i.e. without any additional components. The sealing element, which is preferably electrically insulating, is located in the passage under mechanical prestress. This ensures that the passage is held and securely sealed. In one embodiment, a chamber is designed in such a way that the portion of the housing assigned to it can be introduced into a process chamber. The process chamber is, for example, the container or pipe, etc., in which the at least one process variable is to be determined. The affected part of the housing that surrounds the chamber is therefore designed or used in such a way that contact with the medium occurs or can occur. The process chamber can, for example,particularly at risk of explosion.

[0010] One embodiment consists in that the contact component has at least one electrically conductive, wire-shaped contact element, and that the sealing element is arranged around the contact element - in particular has been produced by an injection molding process. In this embodiment, a wire-shaped (alternatively known as a pin-shaped) contact element is present, which is passed through the passage and ensures the electrical connection between the electrical components in the two chambers. The contact element is made of stainless steel or brass, for example. Contact zones of the contact element are preferably gold-plated for the connection to other components. The sealing element is arranged around the contact element and has preferably been produced around it by an injection molding process.

[0011] One embodiment provides for the sealing element to be pressed into the through-hole in such a way that its volume is reduced by 8% to 20%. The volume of the sealing element in the through-hole is thus reduced by 8% to 20%, which also results in the mechanical preload.

[0012] One design consists in that the sealing element is pressed into the passage in such a way that the conditions for an Ex-d type of protection are met.

[0013] One embodiment provides that the sealing element is made of an elastomer.

[0014] One embodiment involves the sealing element being made of silicone, acrylonitrile butadiene rubber, or ethylene propylene diene rubber. One embodiment provides for the sealing element to have a Shore hardness of 60 Shore A to 80 Shore A.

[0015] One embodiment consists in at least one electronic unit being designed to detect at least one measured variable that depends on the process variable. The electronic unit is, for example, a sensor or at least one sensor component. The process variable can be, for example, the pressure in a container, a pH value, a fill level, a flow rate, a temperature, a viscosity, or a density.

[0016] The invention is explained in more detail with reference to the following figures.

[0017] Fig. 1 shows a section through a schematic representation of a field device and

[0018] Fig. 2 shows a section through a schematic representation of a contact component.

[0019] Fig. 1 shows a section through a field device 1 which is used to determine a pressure in a process chamber.

[0020] For this purpose, the field device 1 is brought partially into the process chamber or into direct or indirect connection with it. The field device 1 has a housing 2 containing two chambers 3. The chambers 3 are separated from one another by a partition 4, which in this case is an integral part of the housing 2. An electronics unit 5 is located in each of the two chambers 3. For electrical contact, e.g., for the transmission of a measurement signal or for the supply of electrical energy, a contact component 6 protrudes through the passage 40. The contact component 6 is designed and its sealing element 61 (cf. Fig. 2) is pressed into the passage 40 in such a way that the passage 40 is sealed and securely closed.

[0021] The electronic unit 5 shown here on the left is designed to generate an electrical signal depending on the pressure, which is processed by the electronic unit 5 shown here on the right. Figure 2 shows a section through an embodiment of the contact component 6.

[0022] A wire-shaped, electrically conductive contact element 60 is surrounded in one area by a sealing element 61. The sealing element 61 consists of an elastomer and is produced by an injection molding process directly around the contact element 60.

[0023] In the assembled state, the sealing element 61 is prestressed in the passage 40. As a result, the contact component 6 is fixed as a whole and, above all, the passage 40 is closed by the contact component 6 alone.

[0024] List of reference symbols

[0025] 1 field device

[0026] 2 housings 3 chambers

[0027] 4 Partition wall

[0028] 5 Electronic unit

[0029] 6 Contact component

[0030] 40 passage 60 contact element

[0031] 61 Sealing element

Claims

Patent claims 1 . Field device (1) of process and automation technology for determining and / or monitoring at least one process variable, with at least one housing (2), wherein the housing (2) has at least two chambers (3) which are separated from one another by a partition wall (4), wherein an electronic unit (5) is arranged in each of the two chambers (3), wherein the partition wall (4) has at least one passage (40) having a substantially constant inner diameter, wherein at least one contact component (6) for contacting the electronic units (5) projects through the passage (40), wherein the contact component (6) has a - preferably electrically insulating - sealing element (61), and wherein the sealing element (61) is pressed into the passage (40) in such a way that the sealing element (61) is under a mechanical prestress in the passage (40) and alone closes the passage (40).

2. Field device (1) according to claim 1, wherein the contact component (6) has at least one electrically conductive, wire-shaped contact element (60), and wherein the sealing element (61) is arranged around the contact element (60) - in particular by a spraying process.

3. Field device (1) according to claim 1 or 2, wherein the sealing element (61) is pressed into the through-bore (40) in such a way that the sealing element (61) is reduced by 8% to 20% of its volume.

4. Field device (1) according to one of claims 1 to 3, wherein the sealing element (61) is pressed into the passage (40) in such a way that conditions for an ignition protection type Ex-d are met.

5. Field device (1) according to one of claims 1 to 4, wherein the sealing element (61) is made of an elastomer.

6. Field device (1) according to one of claims 1 to 5, wherein the sealing element (61) is made of silicone, acrylonitrile butadiene rubber or Made of ethylene propylene diene rubber.

7. Field device (1) according to one of claims 1 to 6, wherein the sealing element (61) has a Shore hardness of 60 Shore A to 80 Shore A.

8. Field device (1) according to one of claims 1 to 7, wherein at least one electronic unit (5) is designed to detect at least one measured variable which is dependent on the process variable.

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