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 to a pressure sensor, a pressure sensor arrangement comprising a pressure sensor and a mounting body, and the uses of the pressure sensor and the pressure sensor arrangement respectively, in particular in relation to measuring the pressure of hydrogen. [Background technology]

[0002] EP 1 146 326 A1 discloses a pressure sensor having the features according to the preamble of claim 1. The known pressure sensor is arranged in an inner bore of the mounting body, which bore communicates with a supply bore through which a pressure of the medium is applied, the pressure then acting on a diaphragm located in a cavity of the sensor housing of the pressure sensor. The diaphragm itself is arranged inside the sensor housing and is operatively connected to a measuring or sensor element that detects the deformation of the diaphragm and deduces the pressure value of the medium therefrom. In one embodiment of the pressure sensor and pressure sensor arrangement respectively, a pressure sensor may be provided that is connected to the inner bore via a separate sealing element interposed axially, which sealing element is locally conical so as to enable sealing of the inner bore and the pressure sensor respectively, so that the medium does not leak out of the mounting body. With respect to the axial extension of the sensor housing, the diaphragm is arranged approximately centrally, i.e. the medium must first pass through the sensor housing into the cavity in order to be able to act on the diaphragm.

[0003] Due to the hydrogen-containing medium, the pressure sensor must be impermeable and resistant to hydrogen, because the sensor housing and the bulkhead are made of metallic materials, which may cause hydrogen to penetrate into the materials and lead to corrosion of the materials, which may result in hydrogen-related cracking with brittle fracture and failure of the pressure sensor. Furthermore, the penetrated hydrogen may also react chemically with the measuring or sensor element placed 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 Summary of the Invention

[0005] The pressure sensor according to the invention having the features of claim 1 comprises a sensor housing which is made particularly compact with respect to its overall axial length and which allows the pressure of the medium to be detected directly or in the region of the bore of the mounting body which is arranged close to the supply for the medium. The bore is made as short as possible with respect to its axial length. The sensor housing comprises a front end in the region of the bore, which front end defines a partition wall. This allows the pressure to be measured very precisely, since the pressure in the bore changes with an increase in the length of the bore, which would distort the pressure measurement result. Furthermore, in this way it is no longer necessary to provide in the sensor housing a means for supplying the medium in the form of a bore up to the region of the partition wall or in the cavity, respectively. Instead, the interior of the sensor housing can only serve to accommodate the measurement or sensor element.

[0006] To achieve the above mentioned advantages, the invention provides that the sealing element is placed away from the front end in the region of the sensor housing where the sensor housing protrudes from the accommodating body and into the bore. In contrast to the prior art, the pressure sensor is sealed in the bore so that no medium can reach the accommodating body. In particular in the case of a hydrogen-containing medium, hydrogen cannot reach the accommodating body at all. Thus, it is not necessary to manufacture the accommodating body from a material resistant to hydrogen, which makes the manufacture of the pressure sensor more cost-effective. In the following, a hydrogen-containing medium is understood to mean a hydrogen-containing fluid medium that contains at least 1 percent hydrogen by volume.

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

[0008] In a preferred further development of the pressure sensor, the sensor housing comprises a sensor housing cone in the area opposite the front face, in the direction of the accommodation body, and the sealing element is arranged in the sensor housing cone.

[0009] The pressure sensor is therefore sealed in the bore between the sensor housing and the mounting body, in this way the hydrogen-containing medium can only penetrate up to the front end and the sensor housing cone of the sensor housing.

[0010] In another preferred further development of the pressure sensor, the sensor housing is made in one piece, which extends from the front side up to and includes the sensor housing cone.

[0011] The area of ​​the sensor housing in contact with the hydrogen-containing medium is made from one piece, which is advantageous in terms of cost and avoids material connections, such as weld seams, coming into contact with the hydrogen-containing medium, which could result in premature aging of the material connections.The front side leading up to and including the sensor housing cone is therefore formed as one piece.

[0012] In a first preferred embodiment of the pressure sensor, which in contrast to the above-mentioned prior art does not require a separate sealing element, a sealing element is provided which is formed integrally with the sensor housing cone. In this way, a particularly simple construction of the pressure sensor is achieved, which requires few components, making the pressure sensor advantageous in terms of price.

[0013] An alternative embodiment is that the sealing element is formed by a component separate from the sensor housing and is connected to the sensor housing by a cone-shaped form-fitting connection. By using a sealing element separate from the sensor housing, the materials of the sealing element and of the sensor housing can be selected in the best possible way to match the respective intended application, so that on the one hand the sealing effect of the sealing element is optimized and on the other hand, for example a material that can be processed particularly easily and cost-effectively is used for the manufacture of the sensor housing.

[0014] A preferred further development of the above proposed embodiment is that the sealing element is shaped in a circular ring shape and the sensor housing has a conical receiving portion for positioning the sealing element, the receiving portion forming a stop surface for the sealing element relative to the mounting direction of the pressure sensor in the inner bore of the mounting body, and that the sealing element and the sensor housing are made of the same or different materials.

[0015] In particular, where the sensor housing, containment body and mounting body have the same or do not differ significantly in coefficient of thermal expansion, a sensor housing may be provided that is directly coupled to the containment body.

[0016] In order to compensate for the different thermal expansion coefficients of the above-mentioned components, a sensor housing may also be provided which is connected to the accommodation body via an interleaved, preferably annular, thermal compensation element, the material of the sensor housing and the material of the accommodation body having different thermal expansion coefficients.

[0017] Fixing the accommodation body in the mounting body is preferably achieved by forming a fixing area on the accommodation body surface in the form of an external thread on the accommodation body surface, which engages with a corresponding internal thread made in the inner bore of the mounting body, so that the necessary sealing force is provided for sealing the accommodation body or the sensor housing by screwing the accommodation body into the inner bore or into the internal thread of the mounting body, respectively.

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

[0019] Furthermore, in order to achieve a procedure for mounting the accommodation body or the pressure sensor, respectively, in the mounting body that is as simple as possible and reproducible in terms of generating a sealing force, an accommodation body is provided that is provided with a tool engagement surface for coupling the pressure sensor to the mounting body, in this way making it possible to generate the required sealing force by means of a threaded connection and by a defined tightening torque of the accommodation body in the inner bore of the mounting body.

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

[0021] A preferred structural embodiment of the pressure sensor device for achieving the desired sealing force is such that the bore is provided with a supply for the medium, which is continuous with a conical portion of the mounting body on the side facing the pressure sensor, and which has a first opening angle in the contact area between the bore in the mounting body and the sensor housing or the sealing element, respectively, which is greater than a second opening angle of the sensor housing or the sealing element, respectively.

[0022] A further development of the shape described in the above paragraph is that in the transition area between the supply part and the conical part of the mounting body, the sealing element rests against the bore in the area of ​​an annular contact area, which ensures that said element is always located in the same place, regardless of the tolerances of the two opening angles in the area of ​​the bore and the sensor housing or the sealing element, respectively.

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

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

[0025] [Figure 1]1 is a longitudinal cross-section of a region of a pressure sensor device for measuring the pressure of hydrogen; [Diagram 2] FIG. 2 is an enlarged view of a detail of FIG. [Diagram 3] FIG. 3 is a longitudinal cross-sectional view of the front end region of the sensor housing of the pressure sensor according to FIGS. [Figure 4] FIG. 4 is a longitudinal cross-sectional view of a sensor housing modified from that of FIG. 3. [Diagram 5] FIG. 3 is a longitudinal cross-sectional view of a pressure sensor which has been modified from the illustration according to FIGS. 1 and 2 in order to compensate for different thermal expansion coefficients of the components of the pressure sensor arrangement. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0027] 1 shows a pressure sensor arrangement 100 for measuring the pressure of an exemplary gaseous medium, specifically hydrogen. The pressure sensor arrangement 100 comprises a mounting body 102 with a stepped bore 104 having a number of steps for receiving a pressure sensor 10. The bore 104 has a longitudinal axis 105. The bore 104 extends along the longitudinal axis 105 and comprises a (cone-shaped) feed 106 on which the pressure of the medium (hydrogen) acts. The feed 106 has a first opening angle α 1 Extending from the mounting body cone 107 is a base 108 extending perpendicular to the longitudinal axis 105 and continuing into a threaded portion 109 of the mounting body 102 having an internal thread 110 formed thereon.

[0028] The pressure sensor 10 comprises a housing body 12 arranged coaxially with respect to a longitudinal axis 105 and a cylindrical part 14 with an external thread 16 which serves as a mounting part and engages with an internal thread 110 of the threaded part 109 to fix the housing body 12 in the inner bore 104 of the mounting body 102. On the outside of the cylindrical part 14 and on the outside of the inner bore 104, respectively, the housing body 12 comprises an enlarged diameter mounting part 18 with a tool engagement surface 20 on its outer surface for interaction with a tool (not shown), in particular a double-ended spanner or torque wrench. The housing body 12, and thus the pressure sensor 10, can be screwed or fixed in the inner bore 104 of the mounting body 102 by means of the tool engagement surface 20.

[0029] Furthermore, the accommodation body 12 comprises a through hole 22 coaxial with the longitudinal axis 105 and a first portion 24 and a second portion 26, which is in the direction opposite to the mounting portion 18 and has an enlarged diameter compared to the first portion 24. The through hole 22, as shown in Figs. 1-3, locally projects from the accommodation body 12 along the longitudinal axis 105 and serves to accommodate the sensor housing 30, which extends by means of a front end section 32 to the supply section 106 of the bore 104. The front end section 32 defines an end of the sensor housing 30 facing away from the accommodation body 12 and terminates in a front face 34 of the sensor housing 30. The front end section 32 forms a partition wall 36 (Fig. 2). In the area facing away from the front face 34 and in the direction of the accommodation body 12, the sensor housing 30 is formed as a first hollow cylindrical section 38 (Fig. 2), which is continuous with a sensor housing cone section 40 (Fig. 2). The sensor housing 30, 30a, 30b is made in one piece from the front surface 34 to the sensor housing cone 40, 40a. By its outer surface, the sensor housing cone 40 has a second opening angle α 2 This second aperture angle α 2 is the first opening angle α defined by the mounting body cone 107 of the bore 104. 1 Therefore, the second aperture angle α 2 is the first aperture angle α 1 is smaller than 1°, for example.

[0030] The sensor housing conical part 40 is also joined in the direction of the housing body 12 by a second hollow cylindrical part 42 (FIG. 3) of the sensor housing 30. The second hollow cylindrical part 42 is then joined in the direction of the housing body 12 by a sensor housing hollow cylindrical part 44 (FIG. 1) which is further enlarged in diameter and which is adapted to enter the second part 26 of the through-hole 22 of the housing body 12 and serve as a stop surface 64 for the sensor housing 30 in the direction of the housing body 12. A material connection 43 is formed between the material of the sensor housing 30, 30a, 30b and the sensor housing hollow cylindrical part 44 in the area opposite the sensor housing conical part 40, 40a in the direction of the housing body 12. The second hollow cylindrical part 42 and the sensor housing hollow cylindrical part 44 are therefore connected to one another by a material connection 43, such as a welded seam.

[0031] 2 and 3, it is apparent that the dividing wall 36 comprises a central connection area 46 for fixing a measuring element 48, in particular in the form of a piezo element 50. The piezo element 50 can operate according to a piezoresistive or piezoelectric measuring principle. The measuring element 48 or the piezo element 50, respectively, is connected to the dividing wall 36 in a manner known per se, so that a deformation of the dividing wall 36 generates an equivalent signal in the measuring element 48.

[0032] At the outer periphery of the connecting region 46, between the measuring element 48 and the partition 36, the partition 36 is provided with an annular elastic section 52 arranged along the longitudinal axis 105 and forming a region in which the wall thickness of the partition 36 is reduced when viewed from the side of the cavity 54 intended as a receiving space for the measuring element 48.

[0033] To sealingly insert the pressure sensor 10 into the inner bore 104 of the mounting body 102 and thus prevent the medium from leaking out of the mounting body 102, a mounting force F acting in the direction of the feed hole 106 is generated via the accommodation body 12 and the threaded connection between the accommodation body 12 and the mounting body 102. In the transition area between the feed hole 106 and the mounting body cone 107, the mounting force F causes the sensor housing 30 to be hermetically sealed with its own sensor housing cone 40 in an annular contact area 56 around the longitudinal axis 105. The contact area 56 is located in front of the accommodation body 12 with respect to the longitudinal axis 105 so that no medium can penetrate up to the accommodation body 12. In the area of ​​its own sensor housing cone 40, the sensor housing 30 therefore also forms a sealing element 60.

[0034] As shown in FIG. 4, instead of the sealing element 60 formed in one piece by the sensor housing cone 40, it is also possible to provide for the use of a modified sensor housing 30a, which comprises a conical receiving part 62 in the sensor housing cone 40a, which extends around the longitudinal axis 105 in the form of a ring, and which comprises a stop surface 64 extending perpendicularly to the longitudinal axis 105. The conical receiving part 62 is arranged to receive the sealing element 60a, which is manufactured as a separate component, in the form of a sealing ring 66 of the same or a different material. By using the sealing element 60a made of the same material as the sensor housing 30a, it is possible to avoid different thermal expansion coefficients in the region of the contact area 56. The use of the sealing element 60a made of a material softer than the sensor housing 30a has the advantage that a relatively small tightening torque is required to seal the contact area 56, which in turn increases the service life of the pressure sensor 10, since a smaller tightening torque is applied to the pressure sensor 10 for sealing. In the axial direction opposite to the mounting direction of the receiving body 12 in the bore 104 of the mounting body 102, the sealing element 60a interacts with the stop surface 64, so that the necessary sealing force is generated by the sensor housing 30a also in the area of ​​the bore 104. As in the case of the sensor housing cone 40, the sealing element 60a or the sealing ring 66, respectively, is spaced apart by a second opening angle α 2 The second opening angle α in the embodiment according to FIG.2 The value of the second aperture angle α 2 However, also in the embodiment of the pressure sensor 10 according to FIG. 4, the contact area 56 is located in front of the containing body 12 with respect to the longitudinal axis 105, so that no medium can penetrate as far as the containing body 12.

[0035] In the embodiment of the pressure sensor 10 shown in Figs. 1-4, the sensor housing 30, 30a is directly connected to the housing body 12. This is advantageous whenever the materials of the housing body 12, the sensor housing 30, 30a and the mounting body 102 have at least approximately the same thermal expansion coefficients, which differ from each other by, for example, not more than 10%. However, as shown in Fig. 5, even in the case of significantly different thermal expansion coefficients, the sensor housing 30b can also be connected to the housing body 12 by radially interleaving an annular thermal compensation element 70 in order to ensure the required impermeability under all operating conditions or pressures and temperatures. The thermal compensation element 70 comprises, for example, an internal thread 72 which interacts with an external thread 74 formed for this purpose on the surface of the sensor housing 30b. In this case, it is advantageous to use threads that rotate in different directions for the external thread 72 on the thermal compensation element 70 and the external thread 16 on the housing body 12 to avoid the thermal compensation element 70 becoming loose in the housing body 12 when the housing body 12 is screwed into the threaded part 109 of the mounting body 102.

[0036] The pressure sensor 10 and pressure sensor arrangement 100 described above, respectively, can be modified and varied in many ways without departing from the concepts inherent in the present invention. [Explanation of symbols]

[0037] 10 Pressure Sensor 12 Storage unit 14 Cylinder section 16 Male thread 18 Mounting part 20 Tool engagement surface 22 Through hole 24 First Part 26 Second Part 30 Sensor housing 30a, 30b Sensor housing 32 Front edge 34 Front 36 Bulkhead 38 First hollow cylindrical section 40, 40a Sensor housing cone part 42 Second hollow cylindrical section 43 Material Connections 44 Sensor housing hollow cylinder section 46 Consolidation area 48 Measuring element 50 Piezo element 52 Elastic area 54 Cavity 56 Contact area 60, 60a sealing element 62 Storage unit 64 Stop surface 66 Sealing ring 68 Exterior 70 Thermal compensation element 72 Female thread 74 Male thread 100 Pressure sensor device 102 Mounting body 104 Inner Hole 105 Longitudinal axis 106 Supply section 107 Mounting body cone part 108 Base 109 Threaded part 110 Female thread F Mounting force α 1 First aperture angle α 2 Second Aperture Angle

Claims

1. A housing body (12) for housing a sensor housing (30, 30a, 30b), the sensor housing (30, 30a, 30b) having a cavity (54) for housing a measuring element (48), the sensor housing (30, 30a, 30b) having a partition wall (36), the measuring element (48) being arranged in operative connection with the partition wall (36) to detect a pressure-dependent deformation of the partition wall (36) for measuring a pressure of a medium, the housing body (12) being insertable by means of a mounting portion (16) into an inner bore (104) of a mounting body (102), in the area of ​​the inner bore (104) the sensor housing (30, 30a, 30b) protruding from the housing body (12) and into the inner bore (104) with respect to a longitudinal axis (105) of the inner bore (104). the sensor housing (30, 30a, 30b) has a front end (32) in the region of the inner bore (104), the front end (32) comprising a accommodating body (12) forming the partition (36), and a sealing element (60, 60a) for sealing the sensor housing (30, 30a, 30b) in the inner bore (104), the sealing element (60, 60a) having an outer surface that is at least locally conical in shape, the sealing element (60, 60a) being arranged in the region of the sensor housing (30, 30a, 30b) away from the front end (32), and the sensor housing (30, 30a, 30b) protruding from the accommodating body (12) and into the inner bore (104).

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

3. 3. The pressure sensor according to claim 2, wherein the sensor housing (30, 30a, 30b) is made in one piece extending from the front surface (34) to the sensor housing cone portion (40, 40a) and including the sensor housing cone portion (40, 40a).

4. 4. The pressure sensor according to claim 2, characterized in that in the area of ​​the direction of the accommodating body (12) opposite the sensor housing cone section (40, 40a), a material connection section (43) is present between the sensor housing (30, 30a, 30b) and the sensor housing hollow cylindrical section (44).

5. 5. A pressure sensor according to claim 2, wherein the sealing element (60) is formed in one piece with the sensor housing cone (40).

6. 5. The pressure sensor according to claim 1, wherein the sealing element (60a) is formed by a component separate from the sensor housing (30a) and is connected to the sensor housing (30a) by a conical form-fitting connection.

7. 7. The pressure sensor 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 receiving portion (62) for positioning the sealing element (60a), the receiving portion (62) forming a stop 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. 8. The pressure sensor according to claim 1, wherein the sensor housing (30, 30a) is directly connected to the containing body (12).

9. 8. A pressure sensor according to claim 1, characterized in that the sensor housing (30b) is connected to the accommodating body (12) via an interleaved, preferably annular, thermal compensation element (70), and the material of the sensor housing (30b) and the material of the accommodating body (12) have different thermal expansion coefficients.

10. The pressure sensor according to any one of claims 1 to 9, characterized in that the housing body (12) comprises a tool engagement surface (20) for connecting the pressure sensor (10) to the mounting body (102).

11. A pressure sensor device (100) comprising a pressure sensor (10) according to any one of claims 1 to 10 and a mounting body (102) having an inner hole (104) for fixing the accommodating body (12) of the pressure sensor (10).

12. The bore (104) is provided with a supply (106) for a medium, which is continuous with a mounting body cone (107) on the side facing the pressure sensor (10), the mounting body cone (107) being arranged in a contact area (56) between the bore (104) in the mounting body (102) and the sensor housing (30, 30b) or the sealing element (60a), respectively, at a second opening angle (α ) of the sensor housing (30, 30b) or the sealing element (60a), respectively. ２ ) １ 2. The pressure sensor device according to claim 1, wherein the pressure sensor device extends in a range of 100 to 2000 mm.

13. 13. The pressure sensor arrangement according to claim 12, characterized in that in the transition region between the supply part (106) and the mounting body cone part (107), the sealing element (60, 60a) contacts the inner bore (104) in the region of the annular contact area (56).

14. Use of a pressure sensor (10) according to any of claims 1 to 10 and / or a pressure sensor arrangement (100) according to any of claims 11 to 13 for measuring the pressure of hydrogen.

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