Pressure sensor, pressure sensor device, and use of pressure sensor

Abstract

The present invention relates to an accommodating body 12 for accommodating a sensor housing 30, 30a, 30b, the sensor housing 30, 30a, 30b comprising a cavity 54 for accommodating a measuring element 48, the sensor housing 30, 30a, 30b comprising a partition wall 36, the measuring element 48 being arranged in operative association with the partition wall 36 to detect a pressure-dependent deformation of the partition wall 36 in order to measure the pressure of a medium, the accommodating body 12 being insertable by means of a mounting portion 16 into an inner bore 104 of a mounting body 102, and in the area of ​​the inner bore 104, The pressure sensor 10 comprises a sensor housing 30, 30a, 30b protruding outward from the accommodating body 12 and into the bore 104 with respect to a longitudinal axis 105 of the bore 104, the sensor housing 30, 30a, 30b having a front end 32 in the area of ​​the bore 104, the front end 32 being provided with the accommodating body 12 forming a partition 36, and a sealing element 60, 60a for sealing the sensor housing 30, 30a, 30b in the bore 104, the sealing element 60, 60a having an outside that is at least locally conical.

Description

Technical Field

[0001] The present invention relates in particular to measuring the pressure of hydrogen, to a pressure sensor, to a pressure sensor device comprising a pressure sensor and a mounting body, and to the use of a pressure sensor and a pressure sensor device respectively.

Background Art

[0002] European Patent Application Publication No. 1146326 discloses a pressure sensor having the features described in the preamble of claim 1. A known pressure sensor is disposed in the inner hole of a mounting body, and this inner hole communicates with a supply hole to which the pressure of a medium is applied. In that case, the pressure acts on a partition wall located in the cavity of the sensor housing of the pressure sensor. The partition wall itself is disposed inside the sensor housing and is operably connected to a measuring or sensor element that detects the deformation of the partition wall and estimates the pressure value of the medium therefrom. In one embodiment of each of the pressure sensor and the pressure sensor device, a pressure sensor connected to the inner hole via a separate sealing element axially interposed may be provided, and this sealing element is locally conical so as to enable the sealing of the inner hole and the pressure sensor respectively and prevent the medium from leaking from the mounting body. With respect to the axial extension of the sensor housing, the partition wall is disposed substantially in the center, that is, in order for the medium to act on the partition wall, it must first enter the cavity through the sensor housing.

[0003] Due to the medium containing hydrogen, the pressure sensor must be impermeable and resistant to hydrogen. The reason is that since the sensor housing and the partition wall are made of a metal material, hydrogen may penetrate into the material and cause corrosion of the material, and as a result, hydrogen-related cracks accompanied by brittle fracture and failure of the pressure sensor may occur. Furthermore, the penetrated hydrogen may also chemically react with the measuring or sensor element disposed inside the sensor housing, which may impair the function of the sensor element.

Prior Art Documents

Patent Documents

[0004] [Patent Document 1] European Patent Application Publication No. 1146326 [Overview of the project]

[0005] The pressure sensor of the present invention, having the features described in claim 1, comprises a sensor housing that is particularly compact in terms of its axial length and enables detection of the pressure of a medium directly or within the region of an internal bore of a mounting body located near a medium supply. The internal bore is made as short as possible in terms of its axial length. The sensor housing has a front end within the region of the internal bore, which defines a partition wall. This allows for very precise pressure measurement because the pressure within the internal bore changes as the length of the internal bore increases, which can distort the pressure measurement results. Furthermore, in this way, it is not necessary to provide a means for supplying the medium within the sensor housing in the form of an internal bore to the region of the partition wall, or within a cavity, respectively. Instead, the interior of the sensor housing can serve only the role of measuring or housing the sensor element.

[0006] To achieve the advantages described above, the present invention is configured such that the sealing element is positioned away from the front end within the region of the sensor housing, where the sensor housing protrudes from the housing body and into the internal bore. In contrast to the prior art, the pressure sensor is sealed within the internal bore so that no medium can reach the housing body. In particular, in the case of a hydrogen-containing medium, the hydrogen cannot reach the housing body at all. Therefore, it is not necessary to manufacture the housing body from a hydrogen-resistant material, thereby making the manufacture of the pressure sensor cost-effective. Hereinafter, a hydrogen-containing medium will be understood to mean a hydrogen-containing fluid medium containing at least 1 percent hydrogen by volume.

[0007] Advantageous further developments of the pressure sensor according to the present invention are shown in the dependent claims.

[0008] In one preferred further development of the pressure sensor, the sensor housing comprises a conical portion of the sensor housing in a region opposite to the front and in the direction of the housing body, and the sealing element is located within the conical portion of the sensor housing.

[0009] Therefore, the pressure sensor is sealed between the sensor housing and the mounting body within the internal bore. In this way, the hydrogen-containing medium can only penetrate to the front end and the conical portion of the sensor housing.

[0010] In another preferred further development of the pressure sensor, the sensor housing is made of a single piece extending from the front to the conical portion of the sensor housing, and including the conical portion of the sensor housing.

[0011] The area of ​​the sensor housing that comes into contact with the hydrogen-containing medium is made from a single component, which is advantageous in terms of cost and avoids the possibility of premature deterioration of material joints, such as welded seams, due to contact with the hydrogen-containing medium. Therefore, the front surface, including the conical portion of the sensor housing, is formed as a single component.

[0012] In contrast to the conventional technology described above, a first preferred embodiment of a pressure sensor that eliminates the need for a separate sealing element is provided, which is integrally formed with the conical portion of the sensor housing. In this way, a particularly simple structure of the pressure sensor is achieved, requiring almost no components, and the pressure sensor is cost-effective.

[0013] In an alternative embodiment, the sealing element may be formed from components separate from the sensor housing and connected to the sensor housing by a conical, form-fitting connector. By using a sealing element separate from the sensor housing, the materials of the sealing element and the sensor housing can be selected to best suit their respective intended applications, thereby optimizing the sealing effect of the sealing element and, on the other hand, allowing for the use of materials that are, for example, particularly easy and cost-effective to process for the manufacture of the sensor housing.

[0014] A preferred further development of the above proposed example is that the sealing element is shaped like an annular ring, and the sensor housing includes a conical dwelling for positioning the sealing element, the dwelling forming a stopper surface for the sealing element in the direction in which the pressure sensor is mounted within the inner bore of the mounting body, and the sealing element and the sensor housing are made of the same or different materials.

[0015] In particular, if the sensor housing, the housing body, and the mounting body have the same or not significantly different coefficients of thermal expansion, the sensor housing may be directly connected to the housing body.

[0016] To compensate for the different thermal expansion coefficients of the above components, a sensor housing may also be provided, connected to the housing body via an interlocking, preferably annular, thermal compensation element, wherein the material of the sensor housing and the material of the housing body have different thermal expansion coefficients.

[0017] The housing body is preferably secured within the mounting body by forming a fixing area on the surface of the housing body in the form of male threads on the surface of the housing body. These male threads engage with corresponding female threads created in the inner bore of the mounting body, and as a result, the necessary sealing force for sealing the housing body or sensor housing is provided by screwing the housing body into the inner bore or into the female threads of the mounting body, respectively.

[0018] Another preferred structural embodiment of the sensor housing for achieving the highest possible sensitivity of the measuring element is such that the sensor housing is formed rotationally symmetric with respect to the longitudinal axis, and at the outer periphery of the connection region to the measuring element, the partition wall has an annular weakening region in which the wall thickness of the partition wall is reduced compared to the connection region.

[0019] Furthermore, in order to achieve a method for mounting the housing body or pressure sensor, respectively, within the mounting body that is as simple as possible and reproducible in terms of generating sealing force, the housing body is provided with a tool engagement surface for connecting the pressure sensor to the mounting body. In this way, it is possible to generate the required sealing force by a predetermined tightening torque of the housing body within the internal bore of the mounting body using a screw connection.

[0020] Furthermore, the present invention also includes a pressure sensor device comprising the pressure sensor according to the present invention described above, and a mounting body having an internal hole for fixing the housing body of the pressure sensor.

[0021] A preferred structural embodiment of a pressure sensor device for achieving a desired sealing force is such that the bore comprises a supply section for the medium, the supply section is continuous with the conical portion of the mounting body on the side in the direction of the pressure sensor, and the conical portion of the mounting body has a first opening angle that is larger than the second opening angle of each of the sensor housings or sealing elements in the contact area between the bore in the mounting body and each of the sensor housings or sealing elements.

[0022] A further development of the shape described in the above paragraph is such that, in the transition region between the supply section and the conical section of the mounting body, the sealing element contacts the inner bore within an annular contact area. This ensures that the element always remains in the same location, regardless of the tolerance of the two opening angles within the regions of the inner bore and the sensor housing or sealing element, respectively.

[0023] Finally, the present invention also encompasses the use of a pressure sensor or a corresponding pressure sensor device according to the present invention for measuring the pressure of hydrogen.

[0024] Further advantages, features, and details of the present invention will become apparent from the following description of preferred embodiments of the present invention and from reference to the drawings. [Brief explanation of the drawing]

[0025] [Figure 1]It is a longitudinal sectional view of a region of a pressure sensor device for measuring the pressure of hydrogen. [Figure 2] It is an enlarged view of the details of FIG. 1. [Figure 3] It is a longitudinal sectional view of the front end region of the sensor housing of the pressure sensor according to FIGS. 1 and 2. [Figure 4] It is also a longitudinal sectional view of the sensor housing modified from FIG. 3. [Figure 5] It is a longitudinal sectional view of a pressure sensor modified from the illustration according to FIGS. 1 and 2 in order to compensate for the different thermal expansion rates of the components of the pressure sensor device.

Mode for Carrying Out the Invention

[0026] Throughout the figures, elements having the same or similar functions are designated by the same reference numerals.

[0027] FIG. 1 shows a pressure sensor device 100 for measuring the pressure of an exemplary gaseous medium, specifically hydrogen. The pressure sensor device 100 includes a mounting body 102 having a stepped inner hole 104 with a plurality of steps for receiving a pressure sensor 10. The inner hole 104 has a longitudinal axis 105. The inner hole 104 extends along the longitudinal axis 105 and includes a supply portion 106 (conical shape) on which the pressure of the medium (hydrogen) acts. A mounting body conical portion 107 having a first opening angle α1 is continuous with the supply portion 106. From the mounting body conical portion 107, a screw portion 109 of the mounting body 102 in which a base portion 108 extends in a direction perpendicular to the longitudinal axis 105 and a female thread 110 is formed is continuous.

[0028] The pressure sensor 10 comprises a housing body 12 arranged coaxially with respect to the longitudinal axis 105, and a cylindrical portion 14 having a male thread 16 that functions as a mounting portion and engages with a female thread 110 of a threaded portion 109 to fix the housing body 12 into the inner hole 104 of the mounting body 102. On the outside of the cylindrical portion 14 and on the outside of the inner hole 104, there is a widened mounting portion 18 on which the housing body 12 has a tool engagement surface 20 on its outer surface for interacting with a tool (not shown), in particular an open-end wrench or torque wrench. The housing body 12, and by extension the pressure sensor 10, can be screwed into or fixed into the inner hole 104 of the mounting body 102 by the tool engagement surface 20.

[0029] Furthermore, the housing body 12 is provided with a through hole 22 coaxial with the longitudinal axis 105, and comprises a first portion 24 and a second portion 26 that is wider in diameter than the first portion 24 and is in the opposite direction to the mounting portion 18. As shown in Figures 1 to 3, the through hole 22 protrudes locally from the housing body 12 along the longitudinal axis 105 and serves to accommodate the sensor housing 30 that extends to the supply portion 106 of the inner hole 104 by the front end area 32. The front end area 32 defines one end of the sensor housing 30 in the opposite direction to the housing body 12 and terminates at the front surface 34 of the sensor housing 30. The front end area 32 forms a partition wall 36 (Figure 2). In the region in the direction of the housing body 12, opposite to the front surface 34, the sensor housing 30 is formed as a first hollow cylindrical portion 38 (Figure 2), to which the sensor housing cone portion 40 (Figure 2) is continuous. The sensor housings 30, 30a, and 30b are made from a single piece of material, from the front surface 34 to the conical portion 40, 40a of the sensor housing. Due to its outer surface, the conical portion 40 of the sensor housing expands at a second opening angle α2, which is smaller than the first opening angle α1 defined by the mounting body conical portion 107 of the inner hole 104. Therefore, the second opening angle α2 is smaller than the first opening angle α1 by, for example, 1°.

[0030] In the direction of the housing body 12, the second hollow cylindrical portion 42 (Figure 3) of the sensor housing 30 is continuous with the conical portion 40 of the sensor housing. Furthermore, in the direction of the housing body 12, the second hollow cylindrical portion 42 is continuous with the sensor housing hollow cylindrical portion 44 (Figure 1), which has a further widening diameter and is configured to enter the second portion 26 of the through hole 22 of the housing body 12 and act as a stopper surface 64 for the sensor housing 30 in the direction of the housing body 12. The material connecting portion 43 is formed between the material of the sensor housing 30, 30a, 30b and the sensor housing hollow cylindrical portion 44 in the region in the direction of the housing body 12, opposite to the conical portions 40, 40a of the sensor housing. Therefore, the second hollow cylindrical portion 42 and the sensor housing hollow cylindrical portion 44 are connected to each other by the material connecting portion 43, such as a welded joint.

[0031] In particular, from Figures 2 and 3, it is clear that the partition wall 36 includes a central connecting region 46 for fixing the measuring element 48, which is in the form of a piezoelectric element 50. The piezoelectric element 50 can operate according to the pressure-resistive or piezoelectric measurement principle. The measuring element 48 or the piezoelectric element 50, each, is connected to the partition wall 36 in a manner known in itself, so that the deformation of the partition wall 36 generates an equivalent signal in the measuring element 48.

[0032] On the outer periphery of the connecting region 46, between the measuring element 48 and the partition wall 36, the partition wall 36 is positioned along the longitudinal axis 105 and includes an annular elastic region 52 in which the wall thickness of the partition wall 36 decreases when viewed from the side of the cavity 54 intended as a housing space for the measuring element 48.

[0033] The pressure sensor 10 is inserted into the inner hole 104 of the mounting body 102 in a sealed manner, thereby generating a mounting force F acting in the direction of the supply hole 106 through the housing body 12 and the screw connection between the housing body 12 and the mounting body 102, in order to prevent the medium from leaking from the mounting body 102. In the transition area between the supply hole 106 and the conical portion 107 of the mounting body, the mounting force F causes the sensor housing 30 to be airtightly sealed by its own sensor housing cone portion 40 in an annular contact area 56 around the longitudinal axis 105. The contact area 56 is positioned in front of the housing body 12 with respect to the longitudinal axis 105, so that no medium can penetrate into the housing body 12. Thus, within the area of ​​its own sensor housing cone portion 40, the sensor housing 30 also forms a sealing element 60.

[0034] As shown in Figure 4, instead of the sealing element 60 integrally formed by the sensor housing cone portion 40, it is also possible to provide a modified sensor housing 30a that includes a conical housing portion 62 extending around the longitudinal axis 105 in the form of a ring within the sensor housing cone portion 40a, and a stopper surface 64 extending perpendicular to the longitudinal axis 105. The conical housing portion 62 is configured to house a sealing element 60a manufactured as a separate component in the form of a sealing ring 66 made of the same or different material. By using a sealing element 60a made of the same material as the sensor housing 30a, it is possible to avoid different coefficients of thermal expansion within the contact area 56. Using a sealing element 60a made of a more flexible material than the sensor housing 30a has the advantage that the tightening torque required to seal the contact area 56 is relatively small, and therefore the tightening torque applied to the pressure sensor 10 for sealing is small, thus increasing the usable life of the pressure sensor 10. In the axial direction opposite to the direction in which the housing body 12 is installed in the inner hole 104 of the mounting body 102, the sealing element 60a interacts with the stop surface 64, thereby generating the necessary sealing force by the sensor housing 30a even within the region of the inner hole 104. Similar to the case of the conical portion 40 of the sensor housing, the sealing element 60a or the sealing ring 66 also has a conical outer surface 68 that expands at a second opening angle α2 and functions as a sealing surface. The value of the second opening angle α2 in the embodiment shown in Figure 4 may differ from the value of the second opening angle α2 in the embodiment shown in Figure 3. However, even in the embodiment of the pressure sensor 10 shown in Figure 4, the contact area 56 is positioned in front of the housing body 12 with respect to the longitudinal axis 105, thereby preventing any medium from penetrating to the housing body 12.

[0035] In the embodiment of the pressure sensor 10 shown in Figures 1-4, the sensor housings 30 and 30a are directly connected to the housing body 12. This is always advantageous when the materials of the housing body 12, the sensor housings 30 and 30a, and the mounting body 102 have at least nearly identical thermal expansion coefficients, differing from each other by, for example, 10% or less. However, as shown in Figure 5, even when the thermal expansion coefficients differ significantly from each other, the sensor housing 30b may be connected to the housing body 12 by radially inserting an annular thermal compensation element 70 to ensure the necessary impermeability under all operating conditions or pressures and temperatures. The thermal compensation element 70 includes, for example, a female thread 72 that interacts with a male thread 74 formed on the surface of the sensor housing 30b for this purpose. In this case, it is advantageous to use threads that rotate in different directions for the male thread 72 on the surface of the thermal compensation element 70 and the male thread 16 of the housing body 12, in order to prevent the thermal compensation element 70 from loosening inside the housing body 12 when the housing body 12 is screwed into the threaded portion 109 of the mounting body 102.

[0036] The pressure sensor 10 and pressure sensor device 100 described above can be modified and altered in many ways without departing from the concepts inherent in the present invention. [Explanation of Symbols]

[0037] 10 Pressure Sensor 12 Main body 14. Cylindrical section 16 Male screw 18 Mounting part 20 Tool engagement surface 22 Through hole 24 Part 1 26. Part 2 30 Sensor housing 30a, 30b Sensor housing 32 Front edge 34 Front 36 Bulkhead 38 First hollow cylindrical section 40, 40a Sensor housing conical section 42 Second hollow cylindrical section 43. Connecting parts of materials 44 Sensor housing hollow cylindrical section 46 Consolidation area 48 measuring elements 50 Piezo elements 52 Elastic Zone 54 Cavity 56 Contact area 60, 60a sealing element 62 Storage Unit 64 Stopping surface 66 sealing rings 68 Exterior 70 Thermal compensation elements 72 Female thread 74 Male screw 100 Pressure sensor device 102 Mounting body 104 Internal bore 105 Longitudinal axis 106 Supply section 107 Mounting body conical section 108 Base 109 Threaded part 110 Female thread F Mounting force α1 First aperture angle α2 second aperture angle

Claims

1. A pressure sensor device (100) comprising a mounting body (102) and a pressure sensor (10) having a housing body (12), The pressure sensor is configured to be inserted into the mounting body (102), the mounting body (102) has an inner hole (104) for fixing the housing body (12) of the pressure sensor (10), the inner hole (104) has a medium supply section (106), the supply section (106) has a conical portion (107) of the mounting body continuous with the pressure sensor (10) on the side in the direction of the pressure sensor (10) when the pressure sensor (10) is inserted, and the pressure sensor (10) further comprises a sensor housing (30, 30a, 30b). The housing body (12) is configured to house the sensor housings (30, 30a, 30b), wherein the sensor housings (30, 30a, 30b) have cavities (54) for housing measuring elements (48), the sensor housings (30, 30a, 30b) have partition walls (36), the measuring elements (48) are arranged to be operationally connected to the partition walls (36) to measure the pressure of the medium and to detect pressure-dependent deformation of the partition walls (36), the housing body (12) can be inserted into the inner hole (104) of the mounting body (102) by a mounting portion (16), and with the pressure sensor (10) inserted, the sensor housings (30, 30a, 30b) are positioned within the region of the inner hole (104) along the longitudinal axis (1 With respect to 05), the sensor housings (30, 30a, 30b) have a front end (32) within the region of the inner hole (104), and the front end (32) of the housing body (12) protrudes from the housing body (12) and into the inner hole (104), and the housing body (12) has a front end (32) that forms the partition wall (36), and sealing elements (60, 60a) for sealing the sensor housings (30, 30a, 30b) within the inner hole (104), wherein the sealing elements (60, 60a) are located away from the front end (32) and within the region of the sensor housings (30, 30a, 30b), and the sensor housings (30, 30a, 30b) protrude from the housing body (12) and into the inner hole (104), With the pressure sensor (10) inserted, the conical portion (107) of the mounting body has a contact area (56) between the inner hole (104) in the mounting body (102) and the sensor housing (30, 30b) or the sealing element (60a), and the second opening angle (α) of the sensor housing (30, 30b) or the sealing element (60a) of each. ２ The first aperture angle (α) is greater than ) １ A pressure sensor device (100) characterized by its ability to spread.

2. The pressure sensor device according to claim 1, characterized in that the sensor housing (30, 30a, 30b) has a sensor housing conical portion (40, 40a) in a region opposite to the front surface (34) and in the direction of the housing body (12), and the sealing element (60, 60a) is arranged within the sensor housing conical portion (40, 40a).

3. The pressure sensor device according to claim 2, characterized in that the sensor housing (30, 30a, 30b) extends from the front surface (34) to the conical portion of the sensor housing (40, 40a) and is made of a single component including the conical portion of the sensor housing (40, 40a).

4. The pressure sensor device according to claim 2, characterized in that, in the region of the housing body (12) in the direction opposite to the conical portion (40, 40a) of the sensor housing, the material connecting portion (43) exists between the sensor housing (30, 30a, 30b) and the hollow cylindrical portion (44) of the sensor housing.

5. The pressure sensor device according to claim 2, characterized in that the sealing element (60) is formed integrally with the conical portion (40) of the sensor housing.

6. The pressure sensor device according to claim 1, characterized in that the sealing element (60a) is formed from a component separate from the sensor housing (30a) and is connected to the sensor housing (30a) by a conical shape-fitting connecting portion.

7. The pressure sensor device according to claim 6, characterized in that the sealing element (60a) is designed as a sealing ring (66), the sensor housing (30a) has a conical housing (62) for positioning the sealing element (60a), the housing (62) forms a stopper surface (64) for the sealing element (60a), and the sealing element (60a) and the sensor housing (30a) are made of the same or different materials.

8. The pressure sensor device according to claim 1, characterized in that the sensor housing (30, 30a) is directly connected to the housing body (12).

9. The pressure sensor device according to claim 1, characterized in that the sensor housing (30b) is connected to the housing body (12) via an interposed thermal compensation element (70), and the material of the sensor housing (30b) and the material of the housing body (12) have different coefficients of thermal expansion.

10. The pressure sensor device according to claim 1, characterized in that the housing body (12) is provided with a tool engagement surface (20) for connecting the pressure sensor (10) to the mounting body (102).

11. The pressure sensor device according to claim 1, characterized in that in the transition region between the supply portion (106) and the mounting body conical portion (107), the sealing element (60, 60a) contacts the inner hole (104) within the annular contact region (56).

12. Use of a pressure sensor device (100) according to any one of claims 1 to 11 for measuring the pressure of hydrogen.

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