Pressure sensor, pressure sensor unit and use of pressure sensor
By designing a compact sensor housing and overall sealing element, the problems of hydrogen infiltration and corrosion in the hydrogen pressure sensor are solved, and low-cost and low-complexity hydrogen pressure measurement is achieved, improving sealing effect and sensitivity.
Patent Information
- Application Number
- CN202380039065.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-05-11
- Filing Date
- 2023-04-05
- Publication Date
- 2024-12-20
AI Technical Summary
Existing pressure sensors are prone to corrosion and chemical reactions when measuring hydrogen pressure due to hydrogen penetration into the material, resulting in failure, and the use of sealing elements increases manufacturing cost and complexity.
A compact sensor housing is designed, with a film formed at the front end, and the sealing element is formed integrally with the sensor housing to avoid hydrogen from contacting the inside of the sensor. A conical or annular sealing structure is adopted, which simplifies the structure and reduces material contact, and uses the same or Materials with similar coefficient of thermal expansion to achieve sealing.
The sealing of hydrogen is achieved, avoids hydrogen infiltration and chemical reactions, reduces manufacturing costs, simplifies the structure, improves the sealing effect and sensitivity, and reduces the risk of material aging.
Smart Images
Figure CN119173749A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a pressure sensor, a pressure sensor unit having a pressure sensor and a mounting body, and the use of the pressure sensor or the pressure sensor unit, in particular for measuring hydrogen pressure. Background Art
[0002] A pressure sensor having the features of the preamble of claim 1 is known from patent document EP1146326A2. The pressure sensor is arranged in a hole in a mounting body, which is connected to a supply hole under medium pressure, wherein the pressure acts on a membrane arranged in a chamber of a sensor housing of the pressure sensor. The membrane is in turn operatively connected to a measuring or sensor element arranged inside the sensor housing, which detects the deformation of the membrane and thereby infers the pressure level of the medium. In one embodiment of the pressure sensor or pressure sensor unit, the pressure sensor is connected to the hole below an axial intermediate layer of a separate sealing element (which is segmentally configured as a cone) so that the sealing element can achieve sealing of the hole or the pressure sensor to prevent the medium from escaping from the mounting body. The membrane is arranged in an approximately middle area relative to the axial extension of the sensor housing, i.e., the medium must first enter the chamber through the sensor housing before it can act on the membrane.
[0003] If the medium contains hydrogen, the pressure sensor must be both sealed and stable against hydrogen. Because in the case of sensor housings and membranes made of metal materials, hydrogen may penetrate into the material and cause material corrosion, which can lead to hydrogen-related crack formation, brittle fracture and failure of the pressure sensor. The infiltrated hydrogen may also chemically react with the measuring or sensor element arranged inside the sensor housing and affect the performance of the sensor element. Summary of the invention
[0004] The pressure sensor according to the invention, having the features of claim 1, has a particularly compact sensor housing viewed along its axial length, which makes it possible to detect the pressure of the medium directly or in the region of the hole of the mounting body close to the medium supply portion. The hole should be as short as possible in the axial extension direction. The sensor housing has a front end in the region of the hole, which forms a membrane. This will allow very precise pressure measurements to be achieved. Because the pressure in the hole changes as the length of the hole increases, this can lead to distortions in the pressure measurement. At the same time, it is also not necessary to supply the medium in the form of a hole inside the sensor housing in the region of the membrane or in the chamber. Instead, the interior of the sensor housing can be used only to accommodate measuring or sensing elements.
[0005] In order to achieve the above advantages, according to the present invention, the sealing element is arranged in a region of the sensor housing extending from the receiving body and extending into the hole, spaced apart from the front end. As a result, compared with the prior art, the pressure sensor in the hole can be sealed before the medium reaches the receiving body. In particular, in the case where the medium contains hydrogen, the hydrogen cannot even reach the receiving body at all. Therefore, the receiving body does not have to be made of a hydrogen-resistant material, which makes the production of the pressure sensor cost-effective. In the following, a medium containing hydrogen is understood to be a hydrogen-containing fluid medium containing at least one volume percentage of hydrogen.
[0006] Preferred embodiments of the pressure sensor according to the invention are specified in the dependent claims.
[0007] In a preferred embodiment of the pressure sensor, the sensor housing has a conical sensor housing section in the region facing away from the end side in the direction of the receiving body; the sealing element is arranged in this conical sensor housing section.
[0008] The sealing of the pressure sensor is therefore carried out in the bore between the sensor housing and the mounting body. Thus, the medium containing hydrogen only reaches the front end of the sensor housing and the conical sensor housing section.
[0009] In a further preferred embodiment of the pressure sensor, the sensor housing is designed in one piece from the end face up to and including the conical sensor housing section.
[0010] The area of the sensor housing that comes into contact with the hydrogen-containing medium is manufactured in one piece, which is cost-effective and therefore does not involve any material-fit connections such as weld seams that come into contact with the hydrogen-containing medium, which could prematurely age. The end face is therefore constructed in one piece up to and including the conical sensor housing section.
[0011] In a first preferred embodiment of the pressure sensor, a separate sealing element can be omitted compared to the prior art, and the sealing element is formed integrally with the sensor housing section, thereby making the structure of the pressure sensor particularly simple and cost-effective due to the small number of required components.
[0012] Alternatively, the sealing element can also be formed by a component separate from the sensor housing, which is connected to the sensor housing by means of a conical form-fit connection. The use of a sealing element separate from the sensor housing enables the materials of the sealing element and the sensor housing to be optimally matched according to the respective intended use, thereby achieving an optimal sealing effect of the sealing element on the one hand and, on the other hand, enabling, for example, the sensor housing to be manufactured using a material that is particularly simple and inexpensive to process.
[0013] In a preferred extension proposed last, the sealing element is constructed in annular shape and the sensor housing has a conical receptacle for positioning the sealing element, wherein the receptacle forms a stop surface for the sealing element opposite to the installation direction of the pressure sensor in the hole of the mounting body, and the sealing element and the sensor housing are made of the same or different materials.
[0014] In particular, when the thermal expansion coefficients of the sensor housing, the receiving body and the mounting body are the same or have little difference, the sensor housing can be directly connected to the receiving body.
[0015] However, in order to compensate for different thermal expansion coefficients of the components, the sensor housing can also be connected to the receiving body beneath an intermediate layer of a preferably annular heat compensation element, wherein the material of the sensor housing and the material of the receiving body have different thermal expansion coefficients.
[0016] The fastening of the receiving body in the mounting body is preferably achieved by configuring the fastening area on the receiving body as an external thread on the receiving body. The external thread cooperates with a matching internal thread in the hole of the mounting body, wherein the required sealing force is applied to seal the receiving body or the sensor housing by screwing the receiving body into the hole or the internal thread of the mounting body.
[0017] In another preferred embodiment of the sensor housing, taking into account that the measuring element should achieve the highest possible sensitivity, the sensor housing is constructed to be rotationally symmetrical relative to the longitudinal axis, and the membrane has an annular weakened area radially outside the connection area with the measuring element, in which the wall thickness of the membrane is reduced relative to the connection area.
[0018] In order to generate the sealing force for mounting the receiving body or the pressure sensor in the mounting body as simply and reproducibly as possible, the receiving body also has a tool engagement surface for connecting the pressure sensor to the mounting body. This makes it possible to generate the required sealing force when using a screw connection by means of a defined tightening torque of the receiving body in the bore of the mounting body.
[0019] The invention also includes a pressure sensor unit having the above-described pressure sensor according to the invention and a mounting body having a hole for fastening a receiving body of the pressure sensor.
[0020] In a preferred embodiment of the pressure sensor unit, in order to achieve a desired sealing force, the hole has a supply section for the medium, which transitions into a conical mounting body section on the side facing the pressure sensor, and the conical mounting body section has a first angle. The first opening angle is greater than a second opening angle of the sensor housing or of the sealing element in the contact region of the opening in the mounting body and the sensor housing or of the sealing element.
[0021] In one embodiment of the geometry described last, the sealing element rests against the bore in a ring-shaped contact region in the transition region between the supply section and the conical mounting body section. This allows the element to be mounted in the same position in the region of the bore and the sensor housing or the sealing element, regardless of the tolerances of the two opening angles.
[0022] Finally, the invention also comprises the use of a pressure sensor according to the invention or a corresponding pressure sensor unit for detecting the pressure of hydrogen. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Further advantages, features and details of the present invention will emerge from the following description of preferred embodiments of the present invention with reference to the accompanying drawings.
[0024] Figure 1 shows a longitudinal section in the region of a pressure sensor unit for measuring hydrogen pressure;
[0025] Figure 2 The enlarged view shows Figure 1 Details;
[0026] Figure 3 The longitudinal section diagram shows Figure 1 and Figure 2 a front end region of a sensor housing of a pressure sensor;
[0027] Figure 4 The longitudinal section also shows the Figure 3 A modified sensor housing; and
[0028] Figure 5 The longitudinal section shows the Figure 1 and Figure 2 Illustration of a modified pressure sensor to compensate for different thermal expansion coefficients of components of the pressure sensor unit.
[0029] Identical elements or elements having the same function are provided with the same reference symbols in the figures. DETAILED DESCRIPTION
[0030] exist Figure 11 shows a pressure sensor unit 100 for measuring the pressure of an exemplary gaseous medium, in particular hydrogen. The pressure sensor unit 100 comprises a mounting body 102 having a multi-staged hole 104 for accommodating the pressure sensor 10. The hole 104 has a longitudinal axis 105. The hole 104 extends along the longitudinal axis 105 and has a (cylindrical) supply section 106, in which the pressure of the medium (hydrogen) acts. A conical mounting body section 107 is connected to the supply section 106, which has a first opening angle α1. The conical mounting body section 107 transitions through a bottom section 108 extending perpendicularly to the longitudinal axis 105 into a threaded section 109 of the mounting body 102, in the region of which an internal thread 110 is formed.
[0031] The pressure sensor 10 has a receiving body 12 arranged concentrically with the longitudinal axis 105, which has a cylindrical section 14 with an external thread 16 as a mounting section, which cooperates with the internal thread 110 of the threaded section 109 in order to fasten the receiving body 12 inside the hole 104 of the mounting body 102. Outside the cylindrical section 14 or outside the hole 104, the receiving body 12 has a mounting section 18 with an increased diameter, which has a tool engagement surface 20 on its outer surface for cooperation with a tool (not shown), in particular a fork wrench or a torque wrench. The receiving body 12 and thus the pressure sensor 10 can be screwed into or fastened in the hole 104 of the mounting body 102 via the tool engagement surface 20.
[0032] Concentrically with the longitudinal axis 105, the receiving body 12 also has a through hole 22, which has a first section 24 and, on the side facing away from the mounting section 18, a second section 26 with a larger diameter than the first section 24. The through hole 22 is used to accommodate the sensor housing 30, according to Figures 1 to 3 As shown, the sensor housing partially protrudes from the receiving body 12 along the longitudinal axis 105 and extends into the supply section 106 of the hole 104 with the front end region 32. The front end region 32 forms the end of the sensor housing 30 facing away from the receiving body 12 and ends in the end side 34 of the sensor housing 30. The front end region 32 forms a membrane 36 ( Figure 2 In the region facing away from the end side 34 in the direction toward the receiving body 12 , the sensor housing 30 transitions into a first hollow cylindrical section 38 ( Figure 2 ), which in turn transitions into a conical sensor housing section 40 ( Figure 2 The sensor housing 30, 30a, 30b is formed in one piece from the end face 34 to the conical sensor housing section 40; 40a. The conical sensor housing section 40 has a second opening angle α2 on its outer side, wherein the second opening angle α2 is smaller than the first opening angle α1 on the conical mounting body section 107 of the hole 104 ( Figure 2 ). For example, the second opening angle α2 is at least 1° smaller than the first opening angle α1.
[0033] The conical sensor housing section 40 transitions in turn in the direction toward the receiving body 12 into a second hollow cylindrical section 42 ( Figure 3 In the direction toward the receiving body 12, the second hollow cylindrical section 42 further transitions into a hollow cylindrical sensor housing section 44 whose diameter increases again ( Figure 1 ), which sensor housing section is designed to be inserted into the second section 26 of the through-opening 22 of the receiving body 12 and to serve as a stop surface 64 for the sensor housing 30 in the direction toward the receiving body 12. The sensor housing 30, 30a, 30b has a material fit connection 43 with a hollow cylindrical sensor housing section 44 in the region facing away from the conical sensor housing section 40, 40a in the direction toward the receiving body 12. The second hollow cylindrical section 42 and the hollow cylindrical sensor housing section 44 are thus mechanically connected to one another by means of the material fit connection 43, such as a weld seam.
[0034] Especially if Figure 2 and Figure 3 As shown, the membrane 36 has a central connection area 46 for fastening a measuring element 48, in particular in the form of a piezoelectric element 50. The piezoelectric element 50 can work according to a piezoresistive or piezoelectric measuring principle. The measuring element 48 or piezoelectric element 50 is connected to the membrane 36 in a known manner so that a deformation of the membrane 36 results in a corresponding signal being generated on the measuring element 48.
[0035] Radially outside the connecting region 46 between the measuring element 48 and the membrane 36 , the membrane 36 has an elastic region 52 circumferentially annularly around the longitudinal axis 105 , in which the wall thickness of the membrane 36 decreases when viewed from the side of a cavity 54 serving as a receiving space for the measuring element 48 .
[0036] In order to arrange the pressure sensor 10 in a sealing manner in the bore 104 of the mounting body 102 to prevent the medium from escaping from the mounting body 102, a mounting force F is generated in the direction of the supply bore 106 by the receiving body 12 and the screw connection between the receiving body 12 and the mounting body 102. The mounting force F causes the sensor housing 30 with its conical sensor housing section 40 to bear sealingly against the contact area 56 which annularly surrounds the longitudinal axis 105 in the transition area between the supply bore 106 and the conical mounting body section 107. The contact area 56 is located in front of the receiving body 12 with respect to the longitudinal axis 105, so that the medium cannot reach the receiving body 12. Therefore, the sensor housing 30 simultaneously forms a sealing element 60 in the area of its conical sensor housing section 40.
[0037] according to Figure 4As shown, instead of the sealing element 60 formed integrally by the conical sensor housing section 40, an improved sensor housing 30a can also be used, which sensor housing has a conical receptacle 62 in the conical sensor housing section 40a, which is annularly around the longitudinal axis 105 and has a stop surface 64 extending perpendicular to the longitudinal axis 105. The conical receptacle 62 is used to positively accommodate a sealing element 60a in the form of a sealing ring 66, which is constructed as a separate component and is made of the same or different material. The use of a sealing element 60a made of the same material as the sensor housing 30a can avoid different thermal expansion coefficients in the contact area 56. The use of a sealing element 60a made of a softer material than the sensor housing 30a has the advantage that only a relatively low tightening torque is required for the sealing contact area 56, which increases the service life of the pressure sensor 10, because it is therefore only subjected to a smaller tightening torque for sealing. Since the sealing element 60a cooperates with the stop surface 64 in the axial direction opposite to the installation direction of the receiving body 12 in the hole 104 of the mounting body 102, the required sealing force is also generated by the sensor housing 30a in the region of the hole 104. Similar to the conical sensor housing section 40a, the sealing element 60a or the sealing ring 66 also has a conical circumferential outer surface 68 as a sealing surface, which has a second opening angle α2. Figure 4 The value of the second opening angle α2 in the embodiment shown can be different from Figure 3 The value of the second opening angle α2 in the embodiment shown. Figure 4 In the exemplary embodiment of pressure sensor 10 , contact region 56 is also located in front of receiving body 12 with respect to longitudinal axis 105 , so that the medium cannot reach receiving body 12 .
[0038] exist Figures 1 to 4 In the exemplary embodiment of the pressure sensor 10 shown, the sensor housing 30, 30a is directly connected to the receiving body 12. It is always advantageous if the materials of the receiving body 12, the sensor housing 30, 30a and the mounting body 102 have at least approximately the same coefficients of thermal expansion, for example differing by no more than 10%. However, even in the case of greatly differing coefficients of thermal expansion, in order to ensure the required tightness in all operating conditions or pressures and temperatures, it is also possible to Figure 5 As shown, the sensor housing 30b is connected to the receiving body 12 below the radial middle layer of the annular heat balancing element 70. For this purpose, the heat balancing element 70 has, for example, an internal thread 72, which cooperates with an external thread 74 formed on the sensor housing 30b. It is advantageous to extend the external thread 72 on the heat balancing element 70 in a different direction from the direction of the external thread 16 of the receiving body 12, so as to prevent the heat balancing element 70 from loosening in the receiving body 12 when the receiving body 12 is screwed into the threaded section 109 of the mounting body 102.
[0039] The pressure sensor 10 or the pressure sensor unit 100 described so far can be transformed or modified in many ways without departing from the concept of the present invention.
[0040] Reference numerals list
[0041] 10. Pressure sensor
[0042] 12 Receiver
[0043] 14 Cylindrical segments
[0044] 16 External thread
[0045] 18 Installation Section
[0046] 20 Tool action surface
[0047] 22 Through Holes
[0048] 24 First Segment
[0049] 26 Second Section
[0050] 30 Sensor housing
[0051] 30a, 30b sensor housing
[0052] 32 front end
[0053] 34 End side
[0054] 36 membrane
[0055] 38 first hollow cylindrical section
[0056] 40, 40a Conical sensor housing section
[0057] 42 Second hollow cylindrical section
[0058] 43 Material matching connection
[0059] 44 Hollow cylindrical sensor housing section
[0060] 46 Connection Area
[0061] 48 Measuring elements
[0062] 50 Piezoelectric element
[0063] 52 Elastic Area
[0064] 54 Chamber
[0065] 56 Contact area
[0066] 60, 60a sealing element
[0067] 62 Accommodation
[0068] 64 Stop surface
[0069] 66 Sealing ring
[0070] 68 External surface
[0071] 70 Heat balance element
[0072] 72 Internal thread
[0073] 74 External thread
[0074] 100 Pressure sensor unit
[0075] 102 Mounting body
[0076] 104 holes
[0077] 105 Vertical Axis
[0078] 106 Supply Section
[0079] 107 Conical mounting body section
[0080] 108 Bottom section
[0081] 109 Threaded section
[0082] 110 Internal thread
[0083] F Installation force
[0084] α1 first angle
[0085] α2 The second angle.
Claims
1. A pressure sensor (10), comprising: a receiving body (12) for accommodating a sensor housing (30; 30a; 30b), wherein the sensor housing (30; 30a; 30b) has a chamber (54) for accommodating a measuring element (48), the sensor housing (30, 30a, 30b) having a membrane (36), the measuring element (48) being arranged to measure the pressure of a medium operatively connected to the membrane (36) in order to detect a pressure-dependent deformation of the membrane (36), wherein the receiving body (12) can be inserted into a hole (104) of a mounting body (102) by means of a mounting section (16), wherein the A sensor housing (30; 30a; 30b) protrudes from the receiving body (12) in the region of the hole (104) about the longitudinal axis (105) of the hole (104) and extends into the hole (104), the sensor housing (30; 30a; 30b) having a front end (32) in the region of the hole (104), the front end (32) forming the membrane (36); and a sealing element (60; 60a) for sealing the sensor housing (30; 30a; 30b) in the hole (104), wherein the sealing element (60; 60a) is at least partially designed as a cone on its outer side, characterized in that The sealing element (60; 60a) is arranged at a distance from the front end (32) in the area of the sensor housing (30; 30a; 30b) in which the sensor housing (30; 30a; 30b) protrudes from the receiving body (12) and into the hole (104).
2. The pressure sensor according to claim 1, characterized in that: The sensor housing (30; 30a; 30b) has a conical sensor housing section (40; 40a) in a region facing away from the end side (34) in the direction toward the receiving body (12); and the sealing element (60; 60a) is arranged in the conical sensor housing section (40; 40a).
3. The pressure sensor according to claim 2, characterized in that: The sensor housing (30; 30a; 30b) is designed in one piece from the end face (34) up to and including the conical sensor housing section (40; 40a).
4. The pressure sensor according to claim 2 or 3, characterized in that: The sensor housing (30; 30a; 30b) has a material fit connection (43) with a hollow cylindrical sensor housing section (44) in a region facing away from the conical sensor housing section (40; 40a) in the direction toward the receiving body (12).
5. The pressure sensor according to any one of claims 2 to 4, characterized in that: The sealing element (60) is formed integrally with the tapered sensor housing section (40).
6. The pressure sensor according to any one of claims 1 to 4, characterized in that: The sealing element (60a) is formed by a component separate from the sensor housing (30a), and the sealing element is connected to the sensor housing (30a) by means of a conical form-fit connection.
7. The pressure sensor according to claim 6, characterized in that: The sealing element (60a) is constructed in the form of a sealing ring (66), and the sensor housing (30a) has a conical receptacle (62) for positioning the sealing element (60a), wherein the receptacle (62) forms a stop surface (64) for the sealing element (60a), and wherein the sealing element (60a) and the sensor housing (30a) are made of the same or different materials.
8. The pressure sensor according to any one of claims 1 to 7, characterized in that: The sensor housing (30; 30a) is directly connected to the receiving body (12).
9. The pressure sensor according to any one of claims 1 to 7, characterized in that: The sensor housing (30b) is connected to the receiving body (12) below an intermediate layer of a preferably annular heat compensation element (70), wherein the material of the sensor housing (30b) and the material of the receiving body (12) have different coefficients of thermal expansion.
10. The pressure sensor according to any one of claims 1 to 9, characterized in that: The receiving body (12) has a tool action surface (20) for connecting the pressure sensor (10) to the mounting body (102).
11. A pressure sensor unit (100) having a pressure sensor (10) configured according to any one of claims 1 to 10 and a mounting body (102) having a hole (104) for fastening a receiving body (12) of the pressure sensor (10).
12. The pressure sensor unit according to claim 1, characterized in that The hole (104) has a supply section (106) for the medium, which transitions into a conical mounting body section (107) on the side facing the pressure sensor (10), and the conical mounting body section (107) has a first opening angle (α1), which is larger than a second opening angle (α2) in a contact area (56) between the hole (104) in the mounting body (102) and the sensor housing (30; 30b) or the sealing element (60a) .
13. The pressure sensor unit according to claim 12, characterized in that In the transition region between the supply section (106) and the conical mounting body section (107), the sealing element (60; 60a) bears against the bore (104) in an annularly shaped contact region (56).
14. Use of a pressure sensor (10) configured according to any one of claims 1 to 10 and / or a pressure sensor unit (100) according to any one of claims 11 to 13 for measuring the pressure of hydrogen.