Calibration Of Pressure Sensors Research Articles

Secondary measurement standard for calibration of dynamic pressure sensor to bridge the gap between existing static and dynamic standards

A secondary measurement standard filling the gap between the available static and dynamic standards was developed. The standard utilizes a quick-opening valve and bursting diaphragms to generate step-like pressures with amplitude of few kilopascals to 10 MPa and with frequency content from 10-2 Hz to 800 Hz. An important design feature of the developed standard lies in the usage of aluminium diaphragms, allowing short rise times and high frequency content. The standard is based on two reference sensors, calibrated statically and dynamically. The reference sensors showed a linear dynamic response in the intermediate frequency range and was in good agreement with the static calibration results. Therefore, extrapolation of shock tube results was implemented. To demonstrate the capabilities of the developed standard, three pressure measurement systems were characterized, and their respective dynamic response was calculated. The results show that the developed standard can provide calibration information that are not currently available.

NSGA-III-Based Production Scheduling Optimization Algorithm for Pressure Sensor Calibration Workshop

Although the NSGA-III algorithm is able to find the global optimal solution and has a good effect on the workshop scheduling optimization, the limitations in population diversity, convergence ability and local optimal solutions make it not applicable to certain situations. Thus, an improved NSGA-III workshop scheduling optimization algorithm is proposed in this work. It aims to address these limitations of the NSGA-III algorithm in processing workshop scheduling optimization. To solve the problem of individual elimination in the traditional NSGA-III algorithm, chaotic mapping is introduced in the improved NSGA-III algorithm to generate new offspring individuals and add the selected winning individuals to the offspring population as the parent population for the next iteration. The proposed algorithm was applied to a pressure sensor calibration workshop. A comparison with the traditional NSGA-III algorithm was conducted through a simulation analysis. The results show that the proposed algorithm can obtain a better convergence performance, improve the optimization ability and avoid falling into local optimal solutions.

Fabrication of Automated Hydrostatic Pressure-Based Densitometer with a Calibrated Pressure Sensor

Fabrication of Automated Hydrostatic Pressure-Based Densitometer with a Calibrated Pressure Sensor

Design, development and commissioning of the control system for the cryogenic distribution system at ESS

The cryogenic distribution system (CDS) at the European Spallation Source (ESS) connects the refrigeration plant with the linear accelerator, consisting in 13 spoke and 30 elliptical cryomodules that are cooled at 2K via multi-transfer lines, individual valveboxes for every cryomodule and an endbox. The designed control system monitors and controls the cooling helium flow through the CDS. The controls architecture for the CDS is based on one Programmable Logic Controller (PLC) per valvebox and another one for the endbox, which are integrated into EPICS through the Controls Network and takes care of the process functions, making it a total of 44 PLCs. This type of integration allows for the remote operation of the CDS from the control room and the necessary interaction of the control system with other related systems and EPICS services like archiving, alarms and save-and-restore. Pre-commissioning activities like loop checks, temperature curve validation, pressure sensor calibration and valve initialization started in summer 2022. Eventually, the system was ready for commissioning and a first cooldown was performed in December 2022. The paper describes the design, development and commissioning of the control system and diverse challenges during the deployment and commissioning activities. Future activities are discussed including the implementation of a sequencer for automatic cooldown and warmup, integration with the cryomodule controls and a master PLC to handle the helium management.

Commissioning of the cryogenic distribution system of the ESS superconducting linac

The European Spallation Source (ESS) is a neutron-scattering facility being built with extensive international collaboration in Lund, Sweden. An essential part of the project is the linear 2.0 GeV proton accelerator. Its superconducting part is designed to comprise 13 spoke and 30 elliptical cryomodules that are cooled at 2K. The cryogenic distribution system (CDS) connects the refrigeration plant with the cryomodules via multi-transfer lines, individual valveboxes for every cryomodule and an endbox. It is designed, manufactured and installed under the responsibility of two ESS in-kind partners. The CDS for the spoke cryomodules (CDS-SL) is supplied by IJCLab, France, the CDS for the elliptical cryomodules (CDS-EL) is supplied by WUST, Poland. Pre-commissioning, commissioning and operation is done by ESS whereby IFJ PAN contributed with valuable advice. Pre-commissioning activities like loop checks, temperature curve validation, pressure sensor calibration or valve initialization and leak tightness tests followed after mechanical or electrical completion of the respective CDS parts and started in summer 2022. Eventually, the system was ready for commissioning and a first cooldown was performed in December 2022. Goal of this commissioning was to acceptance test and check off the system before pilot cryomodule installation in the tunnel started in March 2023. The paper describes diverse challenges regarding TAO and cryo operation. Test results, lessons learnt, and required modifications are discussed as well as preliminary results of retesting and an outlook.

Pressure Sensors: Working Principles of Static and Dynamic Calibration.

This paper starts with an overview of the main principles used for pressure measurements, focusing on their usage in industrial applications' domains. Then, the importance of calibration procedures, namely, static and dynamic calibration of pressure sensors, is analyzed. Regarding calibration, it is important to note that there are several applications where the pressure signals to be measured can have large variations in short periods of time. In industrial applications, particularly in continuous production processes, generally, dynamic pressure measurements are less common; however, they are still required in several cases, such as control loops that are very sensitive to pressure variations, even if the frequencies of those variations are in the range of a few tens of hertz, or even lower. The last part of the paper presents the hardware and software of a flexible and low-cost static and dynamic pressure calibrator that also presents the capability to generate arbitrary waveform pressure signals for calibration and testing purposes. The proposed calibrator also includes the following advantages: remote pressure sensing capabilities that can be used to minimize calibration errors, such as those associated with capillary effects and pressure leakages; portability; and low cost. The paper ends with some experimental results obtained with the proposed calibrator.

Time-varying uncertainty evaluation of the shock wave pressure measurements with small samples in an aerospace shock tube

Shock tube is a crucial device for the dynamic calibration of pressure sensors in aerospace and defense fields. Accurate measurement of the shock wave pressure (SWP) in the shock tube and reliable evaluation of the measurement uncertainty are the basis for improving the calibration accuracy of pressure sensors. However, the repeated measurement results of the SWP in shock tube have typical features of time-varying and small samples, leading to a poor reliability of the measurement uncertainty evaluation. To address this issue, an improved method is proposed to accurately evaluate the time-varying uncertainty of the SWP measurement results with small samples in an aerospace shock tube. The time-varying SWP measurement signals are firstly decomposed into four components by the multicomponent extraction based on signal decomposition algorithms. For the repeated SWP measurement data with small samples, a sample size expansion based on the bootstrap method is presented to reduce the mean estimation error of the four components. A time-varying uncertainty evaluation model of the four components is established based on the conjugate prior Bayesian theory. The reliable evaluation of the time-varying uncertainty of the SWP measurements is finally realized according to the uncertainty propagation principle. Simulations and the SWP measurement experiments in an aerospace shock tube are carried out to validate the performance of the proposed method. The results show that the proposed method works well in the time-varying uncertainty evaluation of the SWP measurements with small samples. Furthermore, the comparative experiments demonstrate the superiority of the proposed method over the Bessel method and the Bayesian method for the SWP measurement uncertainty evaluation in both accuracy and reliability.

Pressure sensor calibration using a water-filled latex finger to account for the mechanical interaction between the hard palate and the deformable human tongue.

We present a calibration system called Dried Water Column (DWC). It applies pressure on a sensor with a latex finger filled with water, which pressure is controlled with a water column. This is intended to mimic the way the deformable tongue mechanically interacts with the hard palate. We show that, once some specificities of the elastic/plastic behavior of the latex finger are taken into account, namely the softening due to Mullins Effect and the non-elastic deformation occurring above a certain pressure level, the DWC provides a reliable measure of the linear relation between the pressure and the output voltage of the sensor within the limited pressure range [0, 2.5kPa]. Such a precise calibration would not be possible with a rigid actuator, which position on the sensor can dramatically influence the measures. Extrapolating the linear relationship thus determined to a larger pressure range compatible with speech production and swallowing ([0, 35kPa]), is possible once it has been verified that the behavior of the sensor is linear over this pressure range. This can be done with any rigid or semi rigid actuator. This reliable calibration procedure can be easily reproduced in any laboratory, and can be applied to any pressure sensor.

MASTER METER PROVER FOR VERIFYING GAS METERS IN THE GAS VOLUME FLOW RANGE UP TO 6500 M3/H

In the article, the need to create a master meter prover for verifying gas meters in the gas volume flow range up to 6500 m3/h in SE Ivano-Frankivskstandardmetrology is presented. An analysis of the existing prover’s types was carried out, indicating the advantages and disadvantages. Reasonable selection master meters of the rotary, turbine and drum type as part of the prover. Features the master meters volume flow ranges, which overlap each other, are determined. The stages of modeling the piping of the reference prover are given. The stages the calibration methodology the reference prover are described. The initial stage involves the calibration of pressure and temperature sensors, which are mounted as part of the prover to exclude the influence of the installation. Calibration the master meters is carried out with the help of transfer standards, which are calibrated on national standards gas volume and volume flow rate. The components of uncertainty that affect the calculation of expanded uncertainty are described in detail. The features of the developed prover software, which contains the requirements of new verification methods for gas meters of various types, are given.

Dynamic Calibration Method of Blast Pressure Pencil Probes Based on Adjustable Shock Tube

Dynamic calibration is one of the important ways to obtain the dynamic performance parameters of pressure sensors, and shock tube calibration is a common method for dynamic calibration of pressure sensors. To study the dynamic calibration method of the shock tube of the blast pressure pencil probes, such as free-field pressure sensors and dynamic pressure sensors, a convenient and adjustable PVC-U (unplasticized polyvinyl chloride) shock tube is developed. Taking the dynamic pressure sensor as the research object, the feasibility of dynamic calibration of shock tube based on CFD (Computational Fluid Dynamics) techniques is discussed. Finally, the dynamic calibration experiment based on shock tube is carried out, and the time-domain and frequency-domain signals are analyzed. The results are in good agreement with the theoretical analysis. The results show that the shock tube can effectively excite the natural frequency of the dynamic pressure sensor, and the developed shock tube can indeed achieve the dynamic calibration and dynamic experiments of pencil probes.

The right turn around: Penrose tourniquet application in paediatrics.

Commercially available tourniquets are ill-suited for paediatric patients with limb circumferences smaller than the required mechanism, forcing surgeons to improvise. This study aimed to quantify pressures exerted by the Penrose tourniquet when applied on a phantom model and evaluate the intra-/inter-rater reproducibility of the technique previously proposed. Eight calibrated pressure sensors were distributed evenly along the inner and outer circumference of a silicon-based model. A 30cm-by-3.2cm ARGYLE Penrose drain, 4-by-4 gauze, marker and ruler were used. The optimal interval for arterial occlusion was determined to be 70% of limb circumference. The tourniquet was secured using two half-knots formed by gauze. Two-turns of the tourniquet about the model generated mean pressures (SD) of 209.43 (SD:35.98mmHg) (95%CI: 195.85-224.00mmHg) (outer-sensor) and 246.32 (SD:61.92mmHg) (95%CI: 221.02-273.49mmHg) (inner-sensor). Three-turns generated mean pressures of 302.07 (SD:23.98mmHg) (95%CI: 292.29-312.53mmHg) (outer-sensor) and 314.44 (SD:56.70mmHg) (95%CI: 291.25-338.25mmHg) (inner-sensor). The Penrose tourniquet has clinical utility, particularly for patients where commercially available tourniquets are not suitable. Current application techniques generate inconsistent pressures. Using the existing model, further refinement can be done to improve the consistency and safety of the application. We recommend using intervals of slightly more than 70% of limb circumference and only two turns of the Penrose tourniquet during application. V.

Improvement for energy efficiency and control characteristics in variable air volume system using in-situ sensor calibration method based on autoencoder

The accuracy of sensor measurement has an important influence on energy efficiency and control characteristics of air conditioning systems. However, the sensor will inevitably have errors due to sensor installation location or aging in the practical system. In previous studies, the sensor virtual in-situ calibration (VIC) method is proposed to diagnose and calibrate sensor faults based on physics-based methods with plenty of sensors. However, the basic sensors are only installed due to the cost and limited installation space in the practical system, which restrains this method. To address this problem, the autoencoder (AE) based on the internal relationship between sensor variables is applied to establish the sensor model to achieve calibration. This paper studies the applicability of the AE that constructs sensor models with limited sensors, and the accuracy of the VIC method under different working conditions. The results show that the AE can well realize the sensor model construction with high accuracy, which lays a foundation for the implementation of the VIC method. Meantime, the accuracy for different scenarios of the single fault is more than 90.75% after calibration, the concurrent fault can also reach more than 88.5%. The supply air temperature calibration will make the continuous regulating valve keep the normal opening to maintain the air volume and ensure the stability of indoor temperature. The static pressure calibration will increase the energy efficiency of the supply fan by 17%, make the VAV box adjust normally, and avoid the disorder of the control loops. The differential pressure sensor calibration will increase the energy efficiency of the water pump by 21%, and ensure normal water flow. Meantime, the calibration of three sensors reduces the time to reach a stable state by more than 20.6%. The VIC method based on AE makes the application scenario of sensor fault calibration more extensive and universal.

Polymer Conductive Membrane-Based Circular Capacitive Pressure Sensors from Non-Touch Mode of Operation to Touch Mode of Operation: An Analytical Solution-Based Method for Design and Numerical Calibration.

Polymer-based conductive membranes play an important role in the development of elastic deflection-based pressure sensors. In this paper, an analytical solution-based method is presented for the design and numerical calibration of polymer conductive membrane-based circular capacitive pressure sensors from non-touch mode of operation to touch mode of operation. The contact problem of a circular membrane in frictionless contact with a rigid flat plate under pressure is analytically solved, and its analytical solution is used for the design of touch mode circular capacitive pressure sensors for the first time. The analytical relationship with input pressure as independent variable and output capacitance as dependent variable is precisely derived and is used for the numerical calibrations of the analytical relationships with input capacitance as the independent variable and output pressure as the dependent variable in order to meet the capacitive pressure sensor mechanism of detecting pressure by measuring capacitance. For the first time, an example showing the design and numerical calibration of a given (given design parameters) polymer conductive membrane-based circular capacitive pressure sensor from non-touch mode of operation to touch mode of operation is provided. Then, the influence of changing several important design parameters on input capacitance–output pressure relationships is comprehensively investigated in order to clarify the desired input–output relationships when changing design parameters.

Workflow to develop 3D designed personalized neonatal CPAP masks using iPhone structured light facial scanning

BackgroundContinuous positive airway pressure (CPAP) is a common mode of respiratory support used in neonatal intensive care units. In preterm infants, nasal CPAP (nCPAP) therapy is often delivered via soft, biocompatible nasal mask suitable for long-term direct skin contact and held firmly against the face. Limited sizes of nCPAP mask contribute to mal-fitting related complications and adverse outcomes in this fragile population. We hypothesized that custom-fit nCPAP masks will improve the fit with less skin pressure and strap tension improving efficacy and reducing complications associated with nCPAP therapy in neonates.MethodsAfter IRB approval and informed consent, we evaluated several methods to develop 3D facial models to test custom 3D nCPAP masks. These methods included camera-based photogrammetry, laser scanning and structured light scanning using a Bellus3D Face Camera Pro and iPhone X running either Bellus3D FaceApp for iPhone, or Heges application. This data was used to provide accurate 3D neonatal facial models. Using CAD software nCPAP inserts were designed to be placed between proprietary nCPAP mask and the model infant’s face. The resulted 3D designed nCPAP mask was form fitted to the model face. Subsequently, nCPAP masks were connected to a ventilator to provide CPAP and calibrated pressure sensors and co-linear tension sensors were placed to measures skin pressure and nCPAP mask strap tension.ResultsPhotogrammetry and laser scanning were not suited to the neonatal face. However, structured light scanning techniques produced accurate 3D neonatal facial models. Individualized nCPAP mask inserts manufactured using 3D printed molds and silicon injection were effective at decreasing surface pressure and mask strap pressure in some cases by more than 50% compared to CPAP masks without inserts.ConclusionsWe found that readily available structured light scanning devices such as the iPhone X are a low cost, safe, rapid, and accurate tool to develop accurate models of preterm infant facial topography. Structured light scanning developed 3D nCPAP inserts applied to commercially available CPAP masks significantly reduced skin pressure and strap tension at clinically relevant CPAP pressures when utilized on model neonatal faces. This workflow maybe useful at producing individualized nCPAP masks for neonates reducing complications due to misfit.

Polymer Conductive Membrane-Based Non-Touch Mode Circular Capacitive Pressure Sensors: An Analytical Solution-Based Method for Design and Numerical Calibration.

In this paper, an analytical solution-based method for the design and numerical calibration of polymer conductive membrane-based non-touch mode circular capacitive pressure sensors is presented. The accurate analytical relationship between the capacitance and applied pressure of the sensors is derived by using the analytical solution for the elastic behavior of the circular polymer conductive membranes under pressure. Based on numerical calculations using the accurate analytical relationship and the analytical solution, the analytical relationship between the pressure as output and the capacitance as input, which is necessary to achieve the capacitive pressure sensor mechanism of detecting pressure by measuring capacitance, is accurately established by least-squares data fitting. An example of how to arrive at the design and numerical calibration of a non-touch mode circular capacitive pressure sensor is first given. Then, the influence of changing design parameters such as membrane thickness and Young’s modulus of elasticity on input–output relationships is investigated, thus clarifying the direction of approaching the desired input–output relationships by changing design parameters.

Realization of an ultra-high pressure dynamic calibrate system by drop hammer based on fiber Bragg grating strain sensor.

In this letter, we propose a novel technique for dynamic ultra-high pressure calibration that measured pressure by FBG based strain sensor. Generally, the traditional method of dynamic ultra-high pressure calibration by standard sensor is costly and it is difficult to improve the accuracy. Therefore, we prefer FBG strain sensor to replace the standard sensor to calibrate the ultra-high pressure. In this proposal, the calibration process is that the central wavelength of the FBG attached to the elastic element changes rapidly with the strain of the elastic element during the drop hammer impact, synchronously. This allows the calibration accuracy to be easily increased to 0.02% and the cost to be reduced by 1/100 compared to traditional calibration techniques. The experiment results show that coefficient of linear correlation between the strain waveform and the pressure signal reaches 0.999. The strain calibration based on FBG is of great significance to the measurement and calibration of dynamic ultra-high pressure sensors.

Reducing Energy Consumption of Pressure Sensor Calibration Using Polynomial HyperNetworks with Fourier Features

Our research aims to reduce the cost of pressure sensor calibration through machine learning. Pressure sensor calibration is a standard process whereby freshly manufactured pressure sensors are subjected to various controlled temperature and pressure setpoints to compute a mapping between the sensor's output and true pressure. Traditionally this mapping is calculated by fitting a polynomial with calibration data. Obtaining this data is costly since a large spectrum of temperature and pressure setpoints are required to model the sensor's behavior. We present a machine learning approach to predict a pre-defined calibration polynomial's parameters while requiring only one-third of the calibration data. Our method learns a pattern from past calibration sessions to predict the calibration polynomial's parameters from partial calibration setpoints for any newly manufactured sensor. We design a novel polynomial hypernetwork coupled with Fourier features and a weighted loss to solve this problem. We perform extensive evaluations and show that the current industry-standard method fails under similar conditions. In contrast, our approach saves two-thirds of the calibration time and cost. Furthermore, we conduct comprehensive ablations to study the effect of Fourier mapping and weighted loss. Code and a novel calibration dataset validated by calibration engineers are also made public.

Novel secondary standard for calibration of dynamic pressure sensors

Abstract Recent research activities in dynamic pressure metrology have been mainly focusing on the development of primary standards like the shock tube or drop-weight apparatus to establish traceability to SI. However, these calibration facilities require a high level of expertise leading to elaborate and time-consuming calibrations. The development of secondary calibrators, based on the reference sensor principle, offering efficient and cost-effective calibrations is essential to meet the needs for industry and to disseminate the dynamic pressure quantity to a wide end-user community. This paper reports a novel secondary calibrator for dynamic pressure measurements up to 300 bar with an expanded uncertainty of about 3.0 %. A heating option enable calibrations at elevated temperatures up to 200 °C making it an ideal solution for convenient calibrations of dynamic pressure transducers used for measurement in internal combustion engine applications.

Improved shock tube method for dynamic calibration of the sensitivity characteristic of piezoresistive pressure sensors

The dynamic calibration of pressure sensors with shock tube system are inevitably affected by the non-ideal shock wave characteristics and complex noise interferences, which limits the achievable accuracy of the dynamic pressure measurements. This paper proposes an improved shock tube (IST) method for identifying the sensitivity characteristic of piezoresistive pressure sensors. The incident shock wave (ISW) velocity attenuation model is first established by a distributed ISW velocity measurement combined with least squares fitting to compensate the shock wave pressure in shock tube. Besides, a signal correction method based on the hybrid adaptive mode decomposition is presented to eliminate the effects of complex noise on the response signals of pressure sensor. An accurate dynamic calibration result of the sensitivity characteristic is finally achieved with the compensated shock wave pressure and corrected response signal. A series of dynamic calibration experiments for a piezoresistive pressure sensor are carried out to verify the performance of the IST method. Results show that the IST method is able to effectively reduce the effects of the non-ideal shock wave and complex noises on the sensitivity calibration results. The mean relative error of sensitivity calibration results with the IST method is only 0.55%, which is about 1/7 times of the results obtained by the usual shock tube method. Furthermore, the sensitivity calibration uncertainty is evaluated and the smaller uncertainty results further verify the superiority of the IST method in high-accuracy dynamic calibration of piezoresistive pressure sensors.

Design and Manufacturing of a Dynamic Pressure Standard Based on Dropping Mass Principle

Dynamic pressure measurements are constantly used in areas such as combustion analysis in the engine cylinder, automotive industry, turbomachinery, aerodynamics, fluid power and control, production processes and within medicine. In these applications, the pressure values range from a few pascals to a few gigapascals, while the frequency ranges studied start below 1 Hz and extend to 1 MHz. Since dynamic pressure calibrators are not commercially available, laboratories working in the field of dynamic pressure measurements have developed some calibrator devices in line with their own needs. Hydraulic and pneumatic shock tubes, pulse and sine wave generator devices can be given as examples of such devices. Even deadweight testers can be included in the class of such devices by using the instantaneous pressure relief method in the negative direction. This study, it is aimed to develop a dynamic pressure device to be used in the calibration of dynamic pressure sensors and to make progress in calibration methods. To develop the aforementioned system, the working method of material testing machines working with the principle of mass reduction was used. The measuring range of the device planned to be produced is aimed to be up to 500 MPa