Pressure transducer with improved temperature error resistance

Abstract

A disclosed example pressure transducer includes: a housing; a fluid inlet configured to provide fluid to a first cavity within the housing; a pressure measurement assembly, the pressure measurement assembly comprising a microelectromechanical pressure sensor configured to output a signal representative of a pressure in the first chamber; and a heater configured to heat the pressure measurement assembly based on the target temperature.

Description

[0001] Related Applications

[0002] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 596,029, entitled “PRESSURE TRANSDUCERS HAVING IMPROVED RESISTANCE TO TEMPERATURE ERROR,” filed on November 3, 2024. The entire contents of U.S. Provisional Patent Application Serial No. 63 / 596,029 are expressly incorporated herein by reference. Technical Field

[0003] The present disclosure relates generally to pressure transducers and, more particularly, to pressure transducers having improved resistance to temperature errors. Background Art

[0004] A pressure sensor or pressure transducer measures the pressure of a fluid input to the sensor compared to a reference pressure. A pressure sensor can be configured to compare the input pressure to a fixed reference pressure or a variable reference pressure. Summary of the invention

[0005] A pressure transducer having improved resistance to temperature errors is disclosed, substantially as illustrated by and described in conjunction with at least one of the accompanying drawings, as more fully set forth in the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] These and other features, aspects and advantages of the present disclosure will be better understood when the following detailed description is read with reference to the accompanying drawings, in which like reference numerals refer to like parts throughout, and in which:

[0007] Figure 1 is a block diagram of an example process control system including a pressure transducer with a fixed reference pressure in accordance with aspects of the present disclosure.

[0008] Figure 2 is a schematic diagram of an example pressure sensor according to aspects of the present disclosure, which example pressure sensor can be used to implement Figure 1 pressure sensor.

[0009] Figure 3 yes Figure 2 A perspective view of an example pressure measurement assembly.

[0010] Figure 4 yes Figure 2 Another perspective view of an example pressure measurement assembly.

[0011] The drawings are not necessarily drawn to scale. Where appropriate, similar or identical reference numerals are used to represent similar or identical components. DETAILED DESCRIPTION

[0012] In order to promote an understanding of the principles of the claimed technology and present its best currently understood mode of operation, reference will now be made to the embodiments shown in the drawings and specific language will be used to describe these embodiments. However, it should be understood that this is not intended to limit the scope of the claimed technology, as these changes and further modifications of the devices shown herein and further applications of the principles of the claimed technology shown herein are generally within the scope of those skilled in the art to which the claimed technology belongs.

[0013] Conventional pressure gauges use pressure measurement components that have high accuracy within certain ranges. However, the operating range of conventional pressure gauges may be insufficient and / or the accuracy may be variable over a sub-range of the operating range. In addition, conventional pressure gauges may be unstable during the life of the sensor.

[0014] Compared to conventional pressure gauges, the disclosed example pressure transducers have higher accuracy and / or higher stability at the same operating pressure. In particular, the disclosed example pressure transducers include electromechanical pressure sensors that provide high accuracy and stability and are packaged to reduce temperature-induced errors. Due to the packaging and nature of the electromechanical pressure sensor, the disclosed example pressure transducers are less susceptible to errors caused by the accumulation of contaminants in the process fluid.

[0015] The disclosed example pressure transducer includes: a housing; a fluid inlet configured to provide fluid to a first chamber within the housing; a pressure measurement assembly having a microelectromechanical pressure sensor configured to output a signal representing the pressure in the first chamber; and a heater configured to heat the pressure measurement assembly based on a target temperature.

[0016] In some example pressure transducers, the microelectromechanical pressure sensor includes a groove etched resonant pressure sensor. In some example pressure transducers, the pressure measurement assembly includes a diaphragm that at least partially defines a first cavity. In some example pressure transducers, the measuring diaphragm is configured to transmit pressure from the first cavity to the microelectromechanical pressure sensor. In some example pressure transducers, the pressure measurement assembly includes a sensor cavity, and the microelectromechanical pressure sensor is arranged in the sensor cavity. In some example pressure transducers, the sensor cavity further includes an incompressible fluid, which is configured to transmit the pressure applied by the diaphragm to the microelectromechanical pressure sensor.

[0017] In some example pressure transducers, the heater includes: a first zone heater configured to heat the housing based on a target temperature; and a second zone heater configured to heat the pressure measurement assembly based on the target temperature. In some example pressure transducers, the microelectromechanical pressure sensor is configured to output a pressure measurement signal having a threshold error less than a threshold error for a fluid having a pressure of at least 1 Torr to 100 Torr. In some example pressure transducers, the microelectromechanical pressure sensor is configured to output a pressure measurement signal having a threshold error less than a threshold error for a fluid having a pressure of at least 10 Torr to 1000 Torr. In some example pressure transducers, the microelectromechanical pressure sensor is configured to output a pressure measurement signal having a threshold error less than a threshold error for a fluid having a pressure of at least 1 Torr to 1000 Torr. In some example pressure transducers, the threshold error is less than 0.1500% of the reading.

[0018] Some example pressure transducers further include measurement circuitry configured to: apply a drive signal to the microelectromechanical pressure sensor; measure a frequency of a resulting signal output by the microelectromechanical pressure sensor; and determine a measured pressure based on the frequency. In some example pressure transducers, the pressure measurement assembly includes a plurality of electrodes extending from the pressure measurement assembly through the housing, and the measurement circuitry is configured to apply the drive signal via at least one of the electrodes.

[0019] In some example pressure transducers, the heater includes: a heating element configured to heat the pressure measurement assembly; a temperature sensor configured to measure a temperature of the pressure measurement assembly; and a control circuit system configured to control the heating element based on the measured temperature.

[0020] Figure 1 is a block diagram of an example process control system 100 that includes a pressure transducer 102 . Figure 1 The example process control system 100 includes a process chamber 104 to which a pressure transducer 102 is fluidly coupled via a fluid input line 106 to measure a pressure of the process chamber 104 .

[0021] The example processing chamber 104 may receive one or more inputs, such as process feed materials, via a corresponding number of feed lines 108a, 108b, which may be controlled via mass flow controllers 110a, 110b.

[0022] The example system 100 may include: a vacuum pump 112 or other pressure controlled pump; and a valve 114 to control flow between the vacuum pump 112 and the process chamber 104. The valve 114 may be controlled by a controller 116, a computing device, and / or any other control technique to maintain the pressure in the process chamber 104 within a desired range. The example pressure transducer 102 is communicatively coupled to the controller 116 to provide pressure feedback to the controller 116 (e.g., for use in a pressure control loop). For example, when the pressure in the process chamber 104 increases, the pressure transducer 102 measures the pressure and provides a signal representing the pressure to the controller 116, which then controls the valve 114 to increase the flow from the process chamber 104 to the vacuum pump 112. The vacuum pump 112 may have an output to any suitable location based on the nature of the process.

[0023] exist Figure 1 In an example of , the pressure transducer 102 is configured to have a fixed pressure 118, and the input pressure of the fluid received via the fluid input pipeline 106 is compared with the fixed pressure to output a pressure signal. For example, as discussed in more detail below, the pressure transducer 102 can be provided with a sealable evacuation port, which can be sealed when the desired pressure is provided within the pressure transducer 102, and / or the pressure transducer 102 can be assembled and sealed within a volume having a desired reference pressure. The fixed pressure 118 can be a vacuum pressure or another predetermined fixed reference pressure, which can be below, at, or above the nominal atmospheric pressure. Figure 1 In the configuration of , the pressure transducer 102 may be used as an absolute pressure sensor.

[0024] Figure 2 is a schematic diagram of an example pressure transducer 200 that may be used to implement Figure 1 The pressure transducer 102 of the example pressure transducer 200 includes a pressure measurement assembly 202 and a housing 204. The pressure transducer 200 is connected to the pressure transducer 102 via a fluid input line 208 (e.g., Figure 1 The device receives fluid through a fluid input line 106, measures the absolute pressure of the received fluid, and outputs one or more signals representing the measured pressure.

[0025] Figure 3 yes Figure 2 2 is a perspective view of an example pressure measurement assembly 202. Figure 4 yes Figure 2 Another perspective view of an example pressure measurement assembly 202. Figure 2, the pressure measurement assembly 202 defines a measurement cavity 222 attached to a fluid input line 208. The example fluid input line 208 is also secured and sealed to the housing 204 (e.g., via a flange). The pressure measurement assembly 202 may also be referred to as a "sensor core," wherein the pressure measurement assembly 202 performs a measurement that is converted into an output signal. The pressure measurement assembly 202 is at least partially surrounded by the housing 204. The housing 204 may provide thermal insulation and / or physical protection to the pressure measurement assembly 202.

[0026] In the illustrated example, the pressure measurement assembly 202 includes a microelectromechanical pressure sensor 206 coupled to a diaphragm 210. In some examples, the microelectromechanical pressure sensor 206 is a trench etch resonant pressure sensor or other silicon micromachined in-plane resonant structure, wherein the microelectromechanical pressure sensor 206 outputs an output signal having a resonant frequency based on the pressure applied to the diaphragm 210. Example trench etch resonant pressure sensors that may be used to implement the microelectromechanical pressure sensor 206 are described in "Advances in Core Fundamental Sensor Technologies Enabling Improvements in the Metrological Transfer Standards of Pressure Measurement," Moisoi et al., Metrologist - NCSLI Global News, Vol. 15, No. 2, pp. 46-55 (2002) ("Moisoi"). The entire contents of Moisoi are incorporated herein by reference.

[0027] The diaphragm 210 is subjected to pressure in the measurement cavity 222, and transmits the pressure to the micro-electromechanical pressure sensor 206 via the incompressible fluid in the sensor cavity 212. The micro-electromechanical pressure sensor 206 is arranged at the distal end of the sensor cavity 212 relative to the diaphragm 210, and the incompressible fluid fills the rest of the sensor cavity 212. In some examples, the incompressible fluid is an incompressible oil, which can be further non-conductive. Additionally or alternatively, the micro-electromechanical pressure sensor 206 includes a second diaphragm (such as a silicon diaphragm) to electrically insulate the micro-electromechanical pressure sensor 206 from the incompressible fluid while transmitting force from the fluid to the resonant component of the micro-electromechanical pressure sensor 206.

[0028] The diaphragm 210 may have an increased or decreased diameter to further increase or decrease the sensitivity of the pressure measurement assembly 202 .

[0029] The micro-electromechanical pressure sensor 206 is connected to the measurement circuit system 214 via ports 220, 222 for supplying input signals and / or providing output signals. The pressure measurement assembly 202 can define a hot furnace chamber 216, which is in fluid communication with the ambient pressure. The example micro-electromechanical pressure sensor 206 can have an integrated pressure reference sealed into the micro-electromechanical pressure sensor 206. For example, a silicon diaphragm within the micro-electromechanical pressure sensor 206 separates the pressure reference from the sensor cavity 212, and the resonant element of the micro-electromechanical pressure sensor 206 resides in the reference pressure cavity of the micro-electromechanical pressure sensor 206. The micro-electromechanical pressure sensor 206 measures the pressure applied to the diaphragm 210 relative to the reference pressure in the integrated pressure reference. The integrated pressure reference in the micro-electromechanical pressure sensor 206 can be established, for example, in the construction of the micro-electromechanical pressure sensor 206.

[0030] exist Figure 2 In the example of FIG. 1 , the surface of the diaphragm 210 has a circular convolution that can be concentric with the diaphragm 210 and allows the diaphragm 210 to flex axially with minimal internal tension changes to improve the linearity of the micro-electro-mechanical pressure sensor 206. Because the pressure on the diaphragm 210 is measured by the micro-electro-mechanical pressure sensor 206 (e.g., by measuring changes in the resonant frequency of the drive circuit), the increase in the linear movement of the diaphragm 210 improves the accuracy of the micro-electro-mechanical pressure sensor 206.

[0031] The pressure transducer 200 further includes one or more heaters 218 to increase the temperature of the microelectromechanical pressure sensor 206 (e.g., to reduce the effects of thermal gradients between the microelectromechanical pressure sensor 206 and the process fluid). The example heater 218 can be arranged around the outside of the housing 204 and / or arranged within the housing 204 and around the outside of the pressure measurement assembly 202. In some examples, the heater 218 is controlled to heat the microelectromechanical pressure sensor 206 to a set point temperature, which in some cases is at least the expected process temperature of the fluid received via the fluid input line 208. In some examples, one or more heat sinks are arranged to form contact between the heater 218 and the housing 204, and / or between the heater 218 and the microelectromechanical pressure sensor 206 to more effectively distribute heat over a larger area of ​​the housing 204 and / or the microelectromechanical pressure sensor 206 and reduce thermal gradients. The housing 204 can be constructed using a thermally conductive material to reduce temperature gradients within the housing 204. Additional and / or alternative locations for the heater 218 may include a bottom surface of the second body 226 , a top surface of the first body 224 , and / or around the fluid input line 208 .

[0032] The heater 218 can improve the measurement accuracy of the micro-electromechanical pressure sensor 206 over a wide range of input pressures and / or the measurement stability over the life of the micro-electromechanical pressure sensor 206. The heater 218 can further prevent long-term errors due to process-induced drift. Figure 2 2 is illustrated as heating two different regions, but pressure transducer 200 may include more or fewer heaters 218 and / or more or fewer heating regions.

[0033] In some examples, the micro-electromechanical pressure sensor 206 is configured to output a pressure measurement signal having a threshold error less than a pressure measurement signal for a fluid having a pressure of at least 1 Torr to 100 Torr (e.g., including a pressure range of at least 1 Torr to 100 Torr, and the pressure range may include a pressure below 1 Torr and / or a pressure above 100 Torr). In some examples, the micro-electromechanical pressure sensor 206 is configured to output a pressure measurement signal having a threshold error less than a pressure measurement signal for a fluid having a pressure of at least 10 Torr to 1000 Torr. In some examples, the micro-electromechanical pressure sensor 206 is configured to output a pressure measurement signal having a threshold error less than a pressure measurement signal for a fluid having a pressure of at least 1 Torr to 1000 Torr. An example threshold error is 0.1500% of the measured output (reading). In other examples, the pressure transducer 200 may be configured to use other pressure ranges as operating ranges, which may include a 2-decade range or a 3-decade range (in Torr order) and / or a larger operating range, while maintaining less than a threshold error within the operating range.

[0034] Pressure transducer 200 further includes control circuitry 228 that receives measurements from measurement circuitry 214 , controls heater power supply 230 to provide power to heater 218 , and receives temperature feedback signals from heater 218 and / or a temperature sensor 232 on sensor housing 204 .

[0035] The control circuit system 228 may be implemented using at least one controller or processor that controls the operation of the pressure transducer 200. The control circuit system 228 receives and processes a plurality of inputs. The control circuit system 228 may include one or more microprocessors (e.g., one or more "general purpose" microprocessors, one or more special purpose microprocessors, and / or ASICs) and / or any other type of processing device. For example, the control circuit system 228 may include one or more digital signal processors (DSPs). The control circuit system 228 may further include a memory device and / or a data storage device.

[0036] The example measurement circuit system 214 is connected to the output port 220 to receive the measurement signal, and / or to the input port 222 to provide an input or drive signal to drive the resonance of the micro-electromechanical pressure sensor 206. For example, the measurement circuit system 214 can apply a drive signal to the micro-electromechanical pressure sensor 206 via the input port 222, measure the frequency of the resulting signal output by the micro-electromechanical pressure sensor 206 via the output port 220, and determine the measured pressure based on the frequency. For example, the measurement circuit system 214 can be calibrated for a set of frequencies and pressures after construction.

[0037] The additional ports may provide heating power to the heater 218 and / or provide temperature sensor data from the temperature sensor 232 for use by the control circuitry 228 in controlling the heater 218 .

[0038] The housing 204 includes a first body 224 and a second body 226. The second body 226 is coupled to the fluid input line 208. For example, the second body 226 can be welded, brazed, or otherwise coupled to the fluid input line 208 to facilitate or improve heat transfer. The first body 224 is coupled to the second body 226 to enclose the pressure measurement assembly 202 within the housing 204. The first body 224 can further include openings through which the ports 220, 222 extend to connect to the measurement circuit system 214 and / or the control circuit system 228.

[0039] Compared to conventional capacitive sensors in which the diaphragm is part of the capacitive electrode and the sensor output varies with diaphragm displacement, the example microelectromechanical pressure sensor 206 has reduced sensitivity to contamination on the diaphragm 210 (e.g., particles from the input line 208). Instead of relying on the sensitivity of the diaphragm 210 to affect the capacitance, the diaphragm 210 transfers the pressure in the measurement cavity 222 to the incompressible fluid in the sensor cavity 212. In this way, the example pressure transducer 200 can extend the life of the microelectromechanical pressure sensor 206 in contamination-prone applications, and the microelectromechanical pressure sensor 206 can be packaged into a smaller package than conventional sensors, for example because the guard volume that reduces contamination on the diaphragm is eliminated.

[0040] The example pressure transducer 200 may further include communication circuitry 234 to communicate the measurements to an external computing or control device (e.g., Figure 1116). For example, communication circuit system 234 may include any wired and / or wireless communication circuit system. In some examples, communication circuit system 234 performs digital communication to transmit digital measurements output by measurement circuit system 214. By using digital communication (such as EtherCAT), accurate measurements made using micro-electromechanical pressure sensor 206 during communication are preserved. Communication circuit system 234 may further receive command signals, which are provided to control circuit system 228. Example command signals include configuration information, such as target heating temperature, temperature reporting interval, and / or any other desired configuration information.

[0041] The device and / or method of the present disclosure can be implemented with hardware, software, or a combination of hardware and software. The present method and / or system can be implemented in a centralized manner in at least one computing system, processor, and / or other logic circuit, or in a distributed manner with different elements spread over several interconnected computing systems, processors, and / or other logic circuits. Any type of computing system or other device adapted to perform the method described herein is suitable. A typical combination of hardware and software can be a processing system with a program or other code, integrated in a welding power source, which controls the welding power source when loaded and executed, so that it implements the method described herein. Another typical embodiment can include a dedicated integrated circuit or chip, such as a field programmable gate array (FPGA), a programmable logic device (PLD) or a complex programmable logic device (CPLD) and / or a system-on-a-chip (SoC). Some embodiments may include a non-transient machine-readable (e.g., computer-readable) medium (e.g., flash memory, optical disk, magnetic storage disk, etc.), which stores one or more lines of code executable by a machine, thereby causing the machine to perform the process described herein. As used herein, the term "non-transitory machine-readable medium" is defined to include all types of machine-readable storage media and to exclude propagating signals.

[0042] As used herein, "and / or" refers to any one or more of the multiple items connected by "and / or" in a list. As an example, "x and / or y" refers to any element in a three-element set {(x), (y), (x, y)}. In other words, "x and / or y" refers to "one or both of x and y". As another example, "x, y and / or z" refers to any element in a seven-element set {(x), (y), (z), (x, y), (x, z), (y, z), (x, y, z)}. In other words, "x, y and / or z" refers to "one or more of x, y and z". As used herein, the term "exemplary" refers to being used as a non-limiting example, instance or diagram. As used herein, the terms "eg," and "for example" give a list of one or more non-limiting examples, instances or diagrams.

[0043] Although the present method and / or system has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the present method and / or system. For example, the frames and / or components of the disclosed examples may be combined, divided, rearranged and / or otherwise modified. In addition, many modifications may be made to adapt specific circumstances or materials to the teachings of the present disclosure without departing from the scope of the present disclosure. Therefore, the present method and / or system is not limited to the specific embodiments disclosed. Alternatively, the present method and / or system will include all embodiments that fall within the scope of the appended claims, both literally and according to the doctrine of equivalents.

Claims

1. A pressure transducer, comprising: case; a fluid inlet configured to provide fluid to a first chamber within the housing; a pressure measurement assembly including a micro-electromechanical pressure sensor configured to output a signal representative of the pressure in the first chamber; as well as A heater is configured to heat the pressure measurement assembly based on a target temperature.

2. The pressure transducer according to claim 1, wherein: The micro-electromechanical pressure sensor includes a trench etched resonant pressure sensor.

3. The pressure transducer according to claim 1, wherein: The pressure measurement assembly includes a diaphragm that at least partially defines the first chamber.

4. The pressure transducer according to claim 3, wherein: The measuring diaphragm is configured to transmit the pressure from the first chamber to the microelectromechanical pressure sensor.

5. The pressure transducer according to claim 4, wherein: The pressure measurement assembly includes a sensor cavity, and the micro-electromechanical pressure sensor is arranged in the sensor cavity.

6. The pressure transducer according to claim 5, wherein: The sensor cavity further includes an incompressible fluid configured to transmit pressure applied by the diaphragm to the micro-electromechanical pressure sensor.

7. The pressure transducer according to claim 1, wherein: The heater comprises: a first zone heater configured to heat the housing based on the target temperature; and A second zone heater is configured to heat the pressure measurement assembly based on the target temperature.

8. The pressure transducer of claim 1, wherein: The micro-electromechanical pressure sensor is configured to output a pressure measurement signal having less than a threshold error for a fluid having a pressure of at least from 1 Torr to 100 Torr.

9. The pressure transducer of claim 1, wherein: The micro-electromechanical pressure sensor is configured to output a pressure measurement signal having less than a threshold error for a fluid having a pressure of at least from 10 Torr to 1000 Torr.

10. The pressure transducer of claim 1, wherein: The micro-electromechanical pressure sensor is configured to output a pressure measurement signal having less than a threshold error for a fluid having a pressure of at least from 1 Torr to 1000 Torr.

11. The pressure transducer of claim 10, wherein: The threshold error is less than 0.1500% of reading.

12. The pressure transducer of claim 1 , further comprising measurement circuitry configured to: applying a driving signal to the micro-electromechanical pressure sensor; measuring the frequency of a resulting signal output by the micro-electromechanical pressure sensor; and A measured pressure is determined based on the frequency.

13. The pressure transducer of claim 12, wherein: The pressure measurement assembly includes a plurality of electrodes extending from the pressure measurement assembly through the housing, and the measurement circuitry is configured to apply the drive signal via at least one of the electrodes.

14. The pressure transducer of claim 1, wherein: The heater comprises: a heating element configured to heat the pressure measurement assembly; a temperature sensor configured to measure a temperature of the pressure measurement assembly; and Control circuitry is configured to control the heating element based on the measured temperature.

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