Pressure transducer for determining first pressure of process medium
By introducing comb-shaped electrodes and a monitoring unit into the pressure measurement transducer, and using electrode phase shift to detect leaks, the problem of difficult-to-detect leaks in sealing elements is solved, thereby improving the reliability and maintenance efficiency of the equipment.
Patent Information
- Application Number
- CN202480048567.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-07-25
- Filing Date
- 2024-06-25
- Publication Date
- 2026-02-24
AI Technical Summary
Existing pressure measurement transducers are difficult to detect quickly when sealing elements leak, resulting in the inability to detect process medium leaks in a timely manner and affecting the normal operation of equipment.
Comb electrodes and a monitoring unit are introduced into the pressure measurement transducer. Leaks in the sealing element are identified by detecting the phase shift between the electrodes. High-frequency signals are used to excite the electrodes to detect the entry of the medium into the rear space at an early stage.
It enables early detection of leaks in sealing elements, improving equipment reliability and maintenance efficiency, and reducing failures and repair costs caused by leaks.
Smart Images
Figure CN121569173A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a pressure measuring transducer for determining a first pressure of a process medium. Background Technology
[0002] Known pressure measurement techniques include absolute pressure transducers, differential pressure transducers, and relative pressure transducers. Absolute pressure transducers determine the primary pressure of a process medium absolutely (i.e., relative to a vacuum), while differential pressure transducers determine the difference between two different pressures of one or more process media. In the case of relative pressure transducers, a reference pressure is used to determine the pressure of the process medium to be measured, where the primary atmospheric pressure in the environment of the relative pressure transducer is used as the reference pressure.
[0003] Pressure measurement transducers have pressure-sensitive measuring elements, so-called pressure sensors, on their first and second surfaces, with pressure applied in each case. In the case of relative and absolute pressure measurement transducers, the process medium pressure to be determined acts on the first surface of the pressure sensor, while the absolute pressure or reference pressure acts on the second surface. In the case of differential pressure measurement transducers, the first and second pressures of the process medium act on both surfaces. The measuring element deflects according to the current relative pressure, which is formed by the difference between the pressures acting on the two surfaces. This deflection is converted into a relative pressure-related electrical signal by means of electronic devices, which can then be used for additional processing or evaluation. In this case, it is particularly important to distinguish between capacitive and piezoresistive pressure sensors. A large number of these pressure measurement transducers are manufactured and sold by the Endress+Hauser Group.
[0004] Pressure sensors within the scope of this invention include, for example, a platform and a ceramic measuring diaphragm, which are pressure-sealed to the platform by means of active solder or brazing to form a measuring chamber. Furthermore, the pressure sensor typically includes a transducer for converting pressure-related deformation of the measuring diaphragm into an electrical main signal, and a main signal path extending through the platform. The transducer can be, for example, a capacitive transducer or a resistive transducer. The main signal path typically includes at least one electrical lead passing through the platform. Instead of a ceramic pressure sensor (also called a pressure sensor), a silicon chip is typically bonded to a silicon substrate.
[0005] In particular, ceramic pressure sensors are often housed within the pressure transducer housing using sealing elements. Without these sealing elements, the process medium can penetrate the housing and cause the pressure transducer to malfunction.
[0006] To detect this leak, a leak hole has been previously provided in the area of the sealing element, allowing the process medium to leak out through the housing in the absence of a seal. The leaked process medium is then visible to service personnel. However, this leak hole requires routine on-site inspection of the pressure transducer. Summary of the Invention
[0007] Therefore, the object of the present invention is to provide a pressure measuring transducer in which leakage of the sealing element can be detected in a simple manner.
[0008] According to the present invention, this objective is achieved by a pressure measuring transducer for determining a first pressure of a process medium, comprising:
[0009] - Housing, which is used to receive the pressure sensor.
[0010] - A pressure sensor having a first surface and a second surface and disposed within a housing, wherein the first surface is positioned on the process medium side and is capable of contacting a first pressure of the process medium, and wherein the second surface is capable of contacting a second pressure.
[0011] - A sealing element, which is implemented and arranged such that it seals the rear space between the pressure-sensitive device and the housing relative to the process medium.
[0012] - A first electrode and a second electrode are arranged in the rear space, wherein the first electrode is implemented as a comb-shaped electrode.
[0013] - A monitoring unit is configured to supply an electrical excitation signal to a first electrode and receive an electrical reception signal from a second electrode, wherein the monitoring unit is further configured to determine the phase shift between the electrical excitation signal and the electrical reception signal and to detect leakage based on the phase shift.
[0014] According to the invention, both electrodes are located in the rear space of the pressure measuring transducer. This rear space corresponds to the intermediate space between the pressure-sensitive device and the housing. The first electrode is supplied with an electrical excitation signal by means of a monitoring unit. The second electrode receives the excitation signal received by the monitoring unit from the first electrode as an electrical reception signal. In this case, the electrical excitation signal interacts with the medium between the first and second electrodes. If the sealing element is intact, air or other predetermined medium exists between the two electrodes. Once the sealing element becomes unsealed and the process medium enters the space between the two electrodes, a phase shift in the electrical excitation signal occurs, which is detected by means of the monitoring unit. Thus, the monitoring unit can detect whether a leak exists. The first and / or second electrodes are particularly implemented as conductive traces or microstrips. Electrodes with a comb-like structure are referred to as comb-shaped electrodes. The exact embodiment of the comb-like structure is determined in particular in conjunction with the frequency of the excitation signal.
[0015] In a further development, the second electrode is provided in the rear space in the form of a metallic coating. This metallic coating can be applied in a simple manner, for example, in the case of pressure sensors, especially on the pressure sensor platform, or on the housing.
[0016] In one embodiment, a first electrode and / or a second electrode are disposed in a region of the sealing element. The first electrode and / or the second electrode can be disposed on or adjacent to the sealing element. This allows for early detection of the presence of process media in the rear space. In this case, the first electrode and / or the second electrode are located in a region of the sealing element away from the process media.
[0017] In an additional embodiment, the first electrode and / or the second electrode are located on the pressure sensor and / or the housing. Both electrodes can be applied to the pressure sensor or the housing. Alternatively, one electrode can be applied to the pressure sensor and the other electrode can be applied to the housing.
[0018] Further developments have provided a pressure measurement transducer that includes at least one holding element configured to hold the pressure sensor in a predetermined position.
[0019] Advantageously, the first electrode and / or the second electrode are located on or at least partially within the retaining element. When only one of the two electrodes is applied to or at least partially within the retaining element, the other electrode can be applied, for example, to a pressure sensor or to a region on the housing or within a sealing element.
[0020] In one embodiment, the housing includes a support area for housing the pressure sensor.
[0021] Another embodiment provides that the electrical excitation signal is a high-frequency signal. High-frequency signals are particularly signals having frequencies in the range of MHz to GHz. Attached Figure Description
[0022] The invention will be explained in more detail based on the accompanying drawings, in which... Figures 1 to 5 As shown below:
[0023] Figure 1 This is the first embodiment of the pressure measuring transducer of the present invention.
[0024] Figure 2 This is the second embodiment of the pressure measuring transducer of the present invention.
[0025] Figure 3 This is the third embodiment of the pressure measuring transducer of the present invention.
[0026] Figure 4 This is the fourth embodiment of the pressure measuring transducer of the present invention.
[0027] Figure 5 This is the fifth embodiment of the pressure measuring transducer of the present invention. Detailed Implementation
[0028] Figure 1 A first embodiment of the pressure measuring transducer 1 of the present invention is shown, which has a ceramic pressure sensor 4 and a housing 3 for holding the pressure sensor 4 in, for example, a container wall, pipe wall or other component of a process system. As an example, the housing 3 includes a sheath 20 having a longitudinal axis A and a radially inwardly extending termination mounting region 13.
[0029] The pressure sensor 4 includes, for example, a pressure-dependent, elastically deformable measuring diaphragm 4b disposed on a ceramic platform 4a. Both the measuring diaphragm 4b and the platform 4a can be formed of ceramic (e.g., alumina (Al₂O₃)) and are pressure-sealed together to seal the pressure chamber 14. The edges of the measuring diaphragm 4b can be connected to the edges of the platform 4a, for example by means of active hard solder or brazing 15, or otherwise (e.g., using glass welding). The measuring diaphragm 4b has a first surface 5 and a second surface 6. The first surface 5 can contact a first pressure p1 of the process medium 20 through an opening 18. The second surface 6 can contact a second pressure p2. The pressure sensor 4 shown can be formed as an absolute pressure sensor. In this case, the pressure chamber 14 sealed behind the measuring diaphragm 4b is emptied, such that the second pressure corresponds to a vacuum pressure. Alternatively, the pressure sensor 4 can be implemented as a reference pressure sensor, in which case the pressure chamber 14 is fed a reference pressure, such as atmospheric pressure, via a hole (not shown) guided through the platform 4a.
[0030] The pressure sensor 4 includes an electromechanical transducer for registering to measure pressure-related deformation of the diaphragm 4b. The transducer can be implemented as a capacitive transducer having at least one capacitor, wherein the capacitor has a capacitance value that varies according to pressure-related deflection of the diaphragm 4b. The at least one capacitor is formed by a measuring electrode 16 applied to the side of the measuring diaphragm 4b facing the platform 4a and a counter electrode 17 applied to the side of the platform 4a facing the measuring diaphragm 4b. The pressure-related capacitance value of the capacitor is registered via measuring electronics (not shown) connected to the measuring electrode 16 and the counter electrode 17. The measuring electronics can be implemented to convert the capacitance value into a pressure-related measurement signal and provide it for additional evaluation and / or processing.
[0031] The pressure sensor 4 is circumferentially positioned on the bearing area 13 using an inserted sealing element 7 (e.g., an O-ring or sealing ring). The rear space 8 formed between the housing 3 and the pressure sensor 4 is sealed by the sealing element 7. The pressure sensor 4 can be secured by means of a threaded ring 21 to prevent axial movement of the pressure sensor 4. Arranged in the rear space 8 are a first electrode 9 and a second electrode 10, implemented as comb-shaped electrodes. A monitoring unit 11 (see...) is provided. Figure 5 The system supplies an electrical excitation signal, particularly a high-frequency signal, to the first electrode 9 and receives an electrical reception signal from the second electrode 10. Depending on the medium between the first electrode 9 and the second electrode 10, a phase shift occurs between the electrical excitation signal and the electrical reception signal. This phase shift arises, in particular, from the change in the effective dielectric constant in the regions of the first electrode 9 and / or the second electrode 10 due to the entry of the process medium 20 into the rear space 8. Based on the phase shift between the electrical excitation signal and the electrical reception signal, leakage can be detected by means of the monitoring unit 11.
[0032] The first electrode 9 and the second electrode 10 can be arranged at different positions in the rear space 8. For example... Figure 1 As shown, for example, one of the two electrodes can be located in the region of the sealing element 7 and the other electrode can be located on the housing 3. Alternatively, as Figure 2 As shown, one of the two electrodes can be located on the housing 3, and the other on the pressure sensor 4. The two electrodes can also be located in the area of the sealing element 7 and on the pressure sensor 4, such as... Figure 3 As shown. Of course, both electrodes 9 and 10 can also be located on the housing 3 or on the pressure sensor 4 (comparatively). Figure 4 The first electrode 9 and / or the second electrode 10 can be applied to the rear space 8, for example, as a metal coating or in the form of a circuit board or microstrip. Advantageously, the first electrode 9 and / or the second electrode 10 are arranged close to the sealing element 7 for early detection of leaks.
[0033] The pressure measuring transducer 1 may also include a holding element 12, such as Figure 5 As shown, this is used to hold the pressure sensor 4 in a predetermined position. For example, the retaining element 12 prevents the pressure sensor 4 from moving in the axial or radial direction. In this case, the first electrode 9 and / or the second electrode 10 can also be applied to the retaining element 12, or at least partially inserted into the retaining element 12. The insertion of one of the two electrodes 9, 10 into or on the retaining element 12 can be combined with other possible arrangements of the electrodes 9, 10.
[0034] List of reference numerals
[0035] 1. Pressure Measurement Transducer
[0036] 2 Process Media
[0037] 3. Shell
[0038] 4. Pressure sensor
[0039] 4a platform
[0040] 4b Measuring diaphragm
[0041] 5 First page
[0042] 6. Second page
[0043] 7 Sealing elements
[0044] 8 Rear Space
[0045] 9 First electrode
[0046] 10 Second electrode
[0047] 11 Monitoring Units
[0048] 12 Holding elements
[0049] 13 Bearing Area
[0050] 14 Pressure Chamber
[0051] 15 connectors
[0052] 16 Measuring electrodes
[0053] 17. Reverse Electrode
[0054] 18 Openings
[0055] 19. Edge Area
[0056] 20 Sheaths
[0057] 21 Threaded ring
Claims
1. A pressure measuring transducer (1) for determining a first pressure (p1) of a process medium (2), comprising: - Housing (3), which is used to receive pressure sensor (4). - The pressure sensor (4), having a first surface (5) and a second surface (6), is arranged in the housing (3), wherein, The first surface (5) is arranged on the process medium side and is able to contact the first pressure (p1) of the process medium (2), wherein the second surface (6) is able to contact the second pressure (p2). - A sealing element (7), which is implemented and arranged such that the sealing element seals the rear space (8) between the pressure-sensitive device (4) and the housing (3) relative to the process medium (2). - A first electrode (9) and a second electrode (10), the first electrode and the second electrode being arranged in the rear space (8), wherein the first electrode (9) is implemented as a comb-shaped electrode. - A monitoring unit (11) is configured to supply an electrical excitation signal to the first electrode (9) and receive an electrical reception signal from the second electrode (10), wherein the monitoring unit (11) is further configured to determine the phase shift between the electrical excitation signal and the electrical reception signal and to detect leakage based on the phase shift.
2. The pressure measuring transducer (1) according to claim 2. in, The second electrode (10) is provided in the rear space (8) in the form of a metal coating.
3. The pressure measuring transducer (1) according to any one of claims 1 to 2. in, The first electrode (9) and / or the second electrode (10) are arranged in the region of the sealing element (7).
4. The pressure measuring transducer (1) according to any one of claims 1 to 3. in, The first electrode (9) and / or the second electrode (10) are located on the pressure sensor (4) and / or the housing (3).
5. The pressure measuring transducer (1) according to any one of claims 1 to 4. in, The pressure measuring transducer (1) includes at least one holding element (12) configured to hold the pressure sensor (4) in a predetermined position.
6. The pressure measuring transducer (1) according to claim 5. in, The first electrode (9) and / or the second electrode (10) are located on or at least partially in the holding element (12).
7. The pressure measuring transducer (1) according to any one of claims 1 to 6. in, The housing (3) includes a bearing area (13) for housing the pressure sensor (4).
8. The pressure measuring transducer (1) according to any one of claims 1 to 7. in, The electrical excitation signal is a high-frequency signal.