Method for producing a differential pressure sensor and corresponding differential pressure sensor

Abstract

The invention relates to a method for producing a differential pressure sensor (1) and a differential pressure sensor (1) produced by the method. The method comprises at least the following steps: providing an essentially rotationally symmetrical electronics module (2) which is provided with a main body (3), an electronics unit (6) and a differential pressure sensor element (7), wherein an outer jacket surface of the main body (3) is produced as a housing adapter (5) which corresponds to a housing (4); and providing a mechanical module (8) which is provided with at least one measuring mechanism (9), wherein a first separating diaphragm (10) and a second separating diaphragm (11) are arranged on the measuring mechanism (9), and an essentially rotationally symmetrical recess (12) of the measuring mechanism (9) for receiving the electronics module (2), wherein an inner contour of the recess (12) matches an outer contour of the electronics module (2) such that the electronics module (2) can be introduced into the recess (12).

Description

Technical Field

[0001] The present invention relates to a method for producing a differential pressure sensor and a differential pressure sensor produced by said method. Background Technology

[0002] Differential pressure sensors are used in industrial metering to measure differential pressure. In particular, differential pressure measuring devices are used to continuously measure the pressure difference in a medium (e.g., liquids, vapors, gases, and dust). For example, differential pressure can be used to determine the fill level of the contents of a storage tank or the flow rate of a medium through a pipeline.

[0003] In pressure measurement technology, so-called semiconductor sensor elements (e.g., silicon chips with doped resistive elements) are commonly used as pressure-sensitive elements. Corresponding differential pressure sensor elements typically have a measuring membrane, the first side of which is exposed to a first pressure during measurement operation, and the second side of which is exposed to a second pressure. The pressure acting on both sides causes deflection of the measuring membrane, corresponding to the differential pressure to be measured. Typically, the pressure sensor chip is so sensitive that it is not directly exposed to the medium whose pressure will be detected. Instead, the first and second pressures are transmitted from the first and second separating membranes to the two sides of the differential pressure sensor element via a pressure-transmitting liquid. Furthermore, overload protection in the form of an overload membrane is sometimes used to protect the differential pressure sensor element from excessively high pressures.

[0004] Differential pressure sensors consist of multiple individual components that are typically integrated into the sensor sequentially and through manual operation. At least partial automation of each individual step would be desirable, but is generally difficult to achieve using the common design of differential pressure sensors.

[0005] A simplified concept of a differential pressure sensor is known from the unpublished patent application DE 10 2019 132 867. The differential pressure sensor essentially consists of a sensor assembly and a body, wherein the sensor assembly has at least one differential pressure sensor element, and two separation diaphragms and an optional overload diaphragm are disposed on the body. The sensor assembly is introduced into a cavity of the body and welded by means of a welding ring. Summary of the Invention

[0006] Therefore, the object of the present invention is to provide a differential pressure sensor with a modular construction that can be manufactured more easily and economically than comparable differential pressure sensors, and to provide a corresponding method for producing such a differential pressure sensor.

[0007] The object of this invention is achieved by a method for producing a differential pressure sensor, the method comprising at least the following steps:

[0008] - Provides a substantially rotationally symmetric electronic module, wherein the electronic module is at least provided with

[0009] ○ Main body, wherein the outer surface of the main body is manufactured as a housing adapter corresponding to the housing.

[0010] ○ Electronic unit, the electronic unit being disposed inside the main body,

[0011] ○ Differential pressure sensor element, the differential pressure sensor element being used to determine the differential pressure generated between a first pressure p1 and a second pressure p2,

[0012] - Provide a mechanical module, wherein the electronic module is at least provided with

[0013] A measuring unit, wherein a first separation membrane and a second separation membrane are disposed on the measuring unit, wherein a first pressure p1 is applied to the first separation membrane and a second pressure p2 is applied to the second separation membrane.

[0014] The measuring unit has a substantially rotationally symmetrical cavity for receiving the electronic module, wherein the inner contour of the cavity matches the outer contour of the electronic module, allowing the electronic module to be inserted into the cavity.

[0015] - The electronic module is introduced into the cavity of the mechanical module, wherein the electronic module is inserted into the cavity until the contact surface of the electronic module impacts the stop surface of the mechanical module.

[0016] - The electronic module is welded or glued to the mechanical module, wherein at least the contact surfaces are welded or glued to the stop surfaces.

[0017] - Axial welding is performed in the opening region of the cavity, such that the mechanical module is completely welded to the electronic module via the weld.

[0018] - Fill at least two pressure transmission lines with a pressure transmission fluid, wherein the at least two pressure transmission lines are configured to transmit the first pressure p1 and the second pressure p2 from the first separation membrane and the second separation membrane, respectively, to two opposite faces of the differential pressure sensor element, and

[0019] Place the housing onto the housing adapter.

[0020] According to the method of the present invention, an electronic module and a mechanical module are provided, which can be manufactured independently of each other and contain all the necessary components of a differential pressure sensor. The electronic module is then inserted into the mechanical module, and the two modules are preferably connected to each other by welding, but also by adhesive bonding. The stop surfaces are preferably connected to the contact surfaces by resistance welding. The differential pressure sensor must then still be filled with a pressure transmission fluid (typically silicone oil), and the housing must be placed on a housing adapter. The housing serves to protect the electronics and preferably has a display unit.

[0021] Due to the modularity of differential pressure sensors, electronic and mechanical modules can be manufactured in parallel and simultaneously, and then assembled in a few steps to form a complete differential pressure sensor.

[0022] In a further development of the method according to the invention, the electronic module is manufactured from a glass-metal feedthrough.

[0023] In another further development of the method according to the invention, the electronic module is preferably produced with an additionally applied ceramic base plate, wherein the differential pressure sensor element is applied to the base plate before the electronic module is provided. The base plate serves, for example, as a support for the differential pressure sensor element and as a means of reducing mechanical impact on the differential pressure sensor element.

[0024] In another further development of the method according to the invention, the electronic module is manufactured with at least one, preferably additionally applied, insulator, wherein the insulator is applied to the differential pressure sensor element prior to the provision of the electronic module. The insulator specifically protects the differential pressure sensor element from external electrical influences.

[0025] Preferably, the mechanical module is provided with an overload membrane in the measuring unit. Before the mechanical module is provided, a first separation membrane is welded to a first outer surface of the measuring unit, and a second separation membrane is initially preferably welded to a support member, which is then welded to a second outer surface of the measuring unit opposite to the first outer surface.

[0026] This objective is also achieved by using a differential pressure sensor manufactured according to the method of the invention. Due to the modular concept of the invention, the differential pressure sensor according to the invention can be manufactured more easily and economically than conventional differential pressure sensors. In particular, the two modules (electronic module and mechanical module) are manufactured independently of each other. Attached Figure Description

[0027] The following is a reference appendix. Figures 1 to 5 The invention will be explained in more detail below. (See figures:)

[0028] Figure 1A schematic embodiment of the electronic module is shown.

[0029] Figure 2 A schematic embodiment of the mechanical module is shown.

[0030] Figure 3 A schematic embodiment of the differential pressure sensor according to the present invention is shown.

[0031] Figure 4 A first schematic diagram of the method according to the present invention is shown.

[0032] Figure 5 A second schematic diagram of the method according to the present invention is shown. Detailed Implementation

[0033] Figure 1 A schematic embodiment of the electronic module 2 of the differential pressure sensor 1 according to the present invention is shown. The electronic module 2 is substantially rotationally symmetric and is, for example, composed of a glass-metal feedthrough. The differential pressure sensor element 7 is attached to the body 3 of the electronic module 2. As an example, the differential pressure sensor element has been applied to the base plate 17, for example, by bonding. Additionally, optionally, an insulator 18 is attached to protect the differential pressure sensor element 7 from unwanted electronic influences. An electronic unit 6 is introduced into the interior of the electronic module 2 and contacts the differential pressure sensor element 7. Furthermore, the outer surface of the electronic module 2 is shaped as a housing adapter 5, such that after the electronic module 2 has been assembled with the mechanical module 8, the housing 4 can be placed onto the corresponding housing adapter 5. A pressure transmission line 16 is also guided through the electronic module 2 to apply a first pressure p1 and a second pressure p2 to the differential pressure sensor element 7. The contact surface 13 is later used to insert the electronic module 2 into the cavity 12 of the mechanical module 8 to a defined depth. The electronic module 2 is initially manufactured separately and supplied to the further manufacturing process of the differential pressure sensor 1.

[0034] The provided mechanical module 8 is in Figure 2 An exemplary embodiment is shown in the diagram. The measuring unit 9 comprises, for example, two carrier disks 21 to which a second separation membrane 11 and a first separation membrane 10 are respectively welded. These two carrier disks 21 form the measuring unit 9 of the mechanical module 8, which also has an optional overload membrane 19 welded between the two carrier disks 21. Pressure transmission lines 16 extend from the first separation membrane 10 and the second separation membrane 11 through the overload membrane 19 to the differential pressure sensor element 7 to apply a first pressure p1 and a second pressure p2, thereby determining the differential pressure. A substantially rotationally symmetrical cavity 12 is used to receive the electronic module 2. A contact surface 13 and a stop surface 14 define the depth to which the electronic module 2 can be inserted into the mechanical module 8.

[0035] Figure 3A possible embodiment of the differential pressure sensing device 1 according to the invention is shown. The electronic module 2 is inserted into the cavity 12 of the mechanical module 8 until the stop surface 14 impacts the contact surface 13. The two modules 2 and 8 are welded to each other in two locations to separate the two pressure sides from each other: once in the region between the stop surface 14 and the contact surface 13 (see weld 22), and once in the opening region of the cavity 12, thus creating an axial weld 20. Alternatively, the stop surface 14 may be glued to the contact surface 13. The housing 4 is finally attached to the housing adapter 5.

[0036] Figure 4 The method according to the present invention is illustrated schematically. In the first step 101, an electronic module 2 is provided, such as... Figure 1 As shown, the electronic module 2 has already been manufactured with a main body 3, a housing adapter 5, an electronic unit 6 located inside the main body 3, and a differential pressure sensor element 7. In the second step 102, a mechanical module 8 is provided, according to... Figure 2 In the embodiment described, the mechanical module 8 has been manufactured with a measuring unit 9 and two separation membranes 10 and 11 disposed thereon, as well as a cavity 12. The first step 101 and the second step 102 can begin simultaneously, allowing the electronic module 2 and the mechanical module 8 to be manufactured and supplied in parallel, as shown below. Figure 5 As illustrated in the diagram.

[0037] Since the outer contour of the electronic module 2 matches the inner contour of the cavity 12, the electronic module 2 can be inserted into the cavity 12. Therefore, in the third step 103, the electronic module 2 is introduced into the cavity 12 of the mechanical module 8. The electronic module 2 is inserted into the cavity 12 to the depth at which the contact surface 13 impacts the stop surface 14 of the mechanical module 8.

[0038] In the fourth step 104 of the method according to the invention, at least the contact surface 13 of the electronic module 2 is welded or glued to the stop surface 14. In the fifth step 105, the electronic module 2 is axially and completely welded to the mechanical module 8 in the opening region 15 of the cavity 12. Since the two pressure sides are now separated from each other, in the sixth step 106, the at least two pressure transmission lines 16 can be filled with pressure transmission fluid. Finally, in the final step 107, the housing 4 is placed on the housing adapter 5.

[0039] List of reference numerals

[0040] 1 Differential pressure sensor

[0041] 2 electronic modules

[0042] 3 main bodies

[0043] 4 housings

[0044] 5. Housing adapter

[0045] 6 electronic units

[0046] 7 Differential pressure sensor elements

[0047] 8 mechanical modules

[0048] 9 measurement units

[0049] 10 First separation membrane

[0050] 11 Second Separation Membrane

[0051] 12 chambers

[0052] 13 contact surfaces

[0053] 14 Stop surfaces

[0054] 15. Opening area of ​​the cavity

[0055] 16 Pressure Transmission Lines

[0056] 17 base plates

[0057] 18 Insulators

[0058] 19 Overload Membrane

[0059] 20 Axial Weld

[0060] 21 carrier disks

[0061] 22 Weld between the stop surface and the contact surface

Claims

1. Method for producing a differential pressure sensor (1), having at least the following method steps: - providing a rotationally symmetrical electronic module (2), wherein The electronic module (2) is provided with at least o a body (3), wherein the outer side of the body (3) is produced as a housing adapter (5) corresponding to a housing (4), o an electronic unit (6), which is arranged inside the body (3), o a differential pressure sensor element (7) for determining a differential pressure generated between a first pressure (pi) and a second pressure (p2), - providing a mechanical module (8), wherein the mechanical module (8) is provided with at least o a measuring cell (9), wherein a first separation membrane (10) and a second separation membrane (11) are arranged on the measuring cell (9), wherein the first pressure (pi) is applied to the first separation membrane (10) and the second pressure (p2) is applied to the second separation membrane (11), o a rotationally symmetrical cavity (12) of the measuring cell (9) for receiving the electronic module (2), wherein the inner contour of the cavity (12) matches the outer contour of the electronic module (2) such that the electronic module (2) can be inserted into the cavity (12), - introducing the electronic module (2) into the cavity (12) of the mechanical module (8), wherein the electronic module (2) is inserted into the cavity (12) until a contact face (13) of the electronic module (2) hits a stop face (14) of the mechanical module (8), - welding and / or gluing the electronic module (2) into the mechanical module (8), wherein at least the contact face (13) is welded or glued to the stop face (14), - performing an axial welding in the opening area (15) of the cavity (12) such that the mechanical module (8) is completely peripherally welded to the electronic module (2) by the welding, - filling at least two pressure transmission lines (16) with a pressure transmission liquid, wherein the at least two pressure transmission lines (16) are provided for transmitting the first pressure (pi) and the second pressure (p2) from the first separation membrane (10) and the second separation membrane (11), respectively, to two opposite faces of the differential pressure sensor element (7), and - placing the housing (4) onto the housing adapter (5).

2. Method for producing a differential pressure sensor (1) according to claim 1, wherein The electronic module (2) is produced from a glass-metal feedthrough.

3. Method for producing a differential pressure sensor (1) according to any one of claims 1-2, wherein The electronic module (2) is produced with a ceramic base disk (17), wherein the differential pressure sensor element (7) is applied to the base disk (17) before the electronic module (2) is provided.

4. Method for producing a differential pressure sensor (1) according to any one of claims 1-2, wherein The electronic module (2) is produced with at least one insulator (18), wherein the insulator (18) is applied to the differential pressure sensor element (7) before the electronic module (2) is provided.

5. Method for producing a differential pressure sensor (1) according to any one of claims 1-2, wherein The mechanical module (8) is provided with an overload membrane (19) in the measuring cell (9).

6. Method for producing a differential pressure sensor (1) according to claim 3, wherein The base disk (17) is applied additionally.

7. Method for producing a differential pressure sensor (1) according to claim 4, wherein The insulator (18) is applied additionally.

8. Differential pressure sensor (1) produced according to any one of claims 1-7.

Images