Bourdon Tube Research Articles

Failure analysis of a C-type bourdon tube

This paper presents the failure analysis of a C-type Bourdon tube made of AISI 316L stainless steel, which was part of a pressure gauge. For the study, chemical composition and microstructure of the Bourdon tube were determined. Additionally, electrochemical attack with oxalic acid was used to asses if the microstructure was suspected of sensitization in samples taken near to and away from the failure. Finally, fractographic analysis of the failed Bourdon tube was accomplished by scanning electron microscopy. The results showed that the failure was due to an intergranular corrosion phenomenon that embrittled the material in the area close to the welding between the Bourdon tube and the joint.

Развитие теории колебаний манометрических трубчатых пружин

The paper considers the development of the theory of oscillations of manometric tubular springs (Bourdon tubes). A review of the work in this field is carried out, the development of the theory of vibrations of tubular springs and methods for calculating the parameters of the oscillatory motion of natural frequencies and attenuation coefficients when moving in a viscous medium are shown. Keywords: OSCILLATION THEORY, MANOMETRIC TUBULAR SPRINGS, OSCILLATION PARAMETERS, OSCILLA-TION FREQUENCY

Final report on key comparison APMP.M.P-K7.3 in hydraulic gauge pressure from 10 MPa to 100 MPa

Main textThis report describes the results of a key comparison among hydraulic high pressure standards that have been maintained by seven National Metrology Institutes (NMIs: NIMT, NMIJ/AIST, NPLI, RCM-LIPI, NMIM, VMI and NMLPHIL). This comparison was carried out during the period March 2016 to October 2017 within the framework of the Asia-Pacific Metrology Programme (APMP) in order to determine their degrees of equivalence in the pressure range from 10 MPa to 100 MPa, gauge mode. The pilot institute was the National Institute of Metrology (Thailand) (NIMT). All participating institutes used hydraulic pressure balance as their pressure standards. In order to ensure reliability, two high precision pressure transducers were used as the transfer standard. The sensing element of the transducers was a precision quartz crystal resonator attached to a small Bourdon tube. During the comparison, the transfer standard was calibrated at the pilot institute two times, before and after circulating the transfer standard to participants. From the two NIMT calibration results, the transfer standard was sufficiently stable to meet the requirements of the comparison. The long-term instability obtained from the two calibration results was taken into account as the uncertainty of the transfer standard for all participants. As the matter of fact NPL India and NMIM participated in this comparison as one of the linkage institutes and participating institutes, respectively. However, it was found later that the systems of hydraulic pressure balance reference standards used in this comparison were not functioning. Therefore, the comparison results were withdrawn. The degrees of equivalence of each national measurement standard were expressed quantitatively by deviations from the key comparison reference value of the corresponding CCM key comparison, CCM.P-K7 through the linkage institute, NMIJ/AIST. In conclusion, the hydraulic pressure standards in the range 10 MPa to 100 MPa, gauge mode of the five participating NMIs were found to be equivalent within their claimed uncertainties.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Manometric Tubular Springs Oscillatory Processes Modeling with Consideration of its Viscoelastic Properties

This article is dedicated to the operation and management of systems of machine-building and aviation enterprises, systems of production, transport, storage of oil and gas, issues of control of technological processes are of great importance. Control of technological processes is carried out by monitoring the pressure and other parameters. These measuring instruments must have high reliability and the necessary accuracy. In this connection, there is a sharp increase in interest in determining the dynamic parameters of the elements of measuring devices. The main elements of such devices are monomeric tubular springs (Bourdon tubes). The paper considers the natural and forced steady-state oscillations of a thin curved rod interacting with a liquid. Based on the principle of possible displacements, a resolving system of partial differential equations and the corresponding boundary conditions are obtained. The problem is solved numerically by the Godunov orthogonal run method, and the Muller method and the Eigen frequencies found are compared with the experimental results. As a result, for a given axial perturbation, it was possible to select such an effect, in the orthogonal direction, that the amplitude of the longitudinal vibrations of the rod at the first resonance decreased by 20 times. The described vibration damping effect is due to the interrelation of transverse and longitudinal vibrations and is fundamentally impossible in the case of a straight rod.

Probing Changes in Pressure With Subpascal Resolution Using an Optical Fiber Fabry–Perot Interferometer

This article reports a novel optical fiber extrinsic Fabry–Perot interferometer (EFPI) for probing pressure changes with subpascal (~0.1 Pa, $\sim 1.45\times 10^{-5}$ psi) resolution. The principal idea of the sensor is to employ a traditional C-shaped Bourdon tube as a mechanical transducer that is coupled to a highly sensitive EFPI device. The cavity of the EFPI device is formed between a gold-coated mirror, mounted to a concave section of the Bourdon tube, and the endface of an optical fiber mounted at the base section of the Bourdon tube. Based on this design, the pressure-induced deflections of the Bourdon tube are directly correlated with the changes in cavity length of the EFPI, which can be determined by analyzing the interference signals. An experiment based on probing hydrostatic pressure changes induced by the addition of single water droplets to a test chamber was performed to quantify the measurement resolution of the proposed sensor because an apparatus for producing exceedingly small, stable, and reproducible pressure changes does not exist. Compared with conventional optical fiber pressure sensors, the proposed pressure sensor requires a simple fabrication process and can be used to measure pressure changes with high sensitivity ( $\sim 23.5~\mu \text{m}$ /kPa, cavity length change/pressure change). Moreover, the sensitivity and resolution of the pressure sensor can be flexibly adjusted using Bourdon tubes designed for different dynamic ranges (e.g., 0–70 MPa, 0–10152 psi). It is believed that the proposed novel pressure sensor has the potential to find a wide range of applications that require precise instrumentation.

High sensitivity optical fiber pressure sensor based on thin-walled oval cylinder

In this study, an optical fiber pressure sensor based on a thin-walled oval cylinder is proposed. To sense the degree of deformation, a pair of fiber Bragg gratings (FBGs) are fixed on the outer wall of the oval cylinder. A finite element analysis is performed to analyze the sensing characteristic of the sensor. The temperature cross-sensitivity is determined using an elimination method. The experiment results show that the pressure sensitivity is 1.198 nm/MPa within a range of 0–1 MPa, with a precision of 0.011 MPa. The proposed sensor combines the advantages of a thin-walled cylinder and a bourdon tube, which realizes pressure measurement with high sensitivity and low crosstalk. The sensor can be applied to specific urban pipeline pressure monitoring.

Material Types and Wall Thickness Effects on Bourdon Tube Tip Travel using Solid works

Bourdon-type pressure devices are used to detect pressure in industrial installations and pressure monitoring systems. Bourdon tubes are manufactured in various engineering shapes like circular-C, helix, and spiral, to serve the use of this tube in terms of positioning and accuracy. The tip of the Bordoun tube is a pressure-sensitive element. The applied input pressure causes the tube tip to be shifted or translated from the initial position. In this study, the pressure measurement in Bordoun tube was simulated at different sections and different axial ratios of multiple metals to obtain the best tube tilp deviation using the Solidworks program. Simulation results expressing the differentiation of tip travel values using four materials, three axial ratios, and four cross-section types. The results show that best material in terms of maximum tip travel was Zinc AZ-12, and for any material and regular wall thickness, the axial ratio (0.3) gives the best response. Also, the results show other materials' response and effect of change axial ratio.

A Temperature Compensated Non-Contact Pressure Transducer Using Hall Sensor and Bourdon Tube

This paper describes the design of a simple non-contact-type pressure transducer using a Bourdon tube and a Hall sensor where the effect of atmospheric temperature is compensated. In this design, a pressure sensing Hall IC is fixed with the nonmagnetic aluminum casing of a Bourdon gauge in front of a tiny disc-type permanent magnet rigidly attached with the free tip of the Bourdon tube. With the increase of pressure of the fluid inside the Bourdon tube, the free end along with the magnet moves toward the Hall sensor, and the magnetic field intensity due to the magnet on the Hall sensor increases with an increase of pressure. Due to this magnetic field, the outputs of the Hall sensor and the transducer circuit consisting of a differential amplifier and an instrumentation amplifier increase with the increase of pressure of the fluid inside the Bourdon tube. The transducer circuit consists of a unity gain differential amplifier circuit where the output of a second identical temperature sensing Hall IC is subtracted from the pressure sensing Hall IC output in order to compensate the effect of ambient temperature in the proposed transducer. The theoretical equations describing the operation of the transducer are derived in this paper. The static characteristic curves of a prototype design of the transducer are determined experimentally. The experimental results are reported in this paper. The characteristics curves are found to follow the theoretical equations with good repeatability and are free from ambient temperature effect.

The effect of PTFE addition on mechanical and anti-corrosion properties of coating of heat exchangers

Through adjusting the concentration of poly tetra fluoroethylene (PTFE) particles of the Ni–Cu–P composite coatings, the Ni–Cu–P-PTFE composite coatings with different PTFE concentration were obtained. Further experiments and studies demonstrate that the elasticity modulus and the microhardness of Ni–Cu–P-PTFE coating are inversely proportional to the content of PTFE particles. Meanwhile, adhesion strength between Ni–Cu–P-PTFE coatings and matrix is not just influenced by the content of PTFE particles in the coatings, but also by the surfactant in the bath. Furthermore, the Ni–Cu–P-PTFE coating performs well corrosion resistance. However, due to the increase of pores in the coating caused by the increasing number of PTFE particles, the thermal conductivity and the corrosion resistance, as well as the mechanical properties, of the coating will reduce correspondingly. So when the Ni–Cu–P-PTFE composite coating is utilized, PTFE content in the plating solution should be kept within an appropriate range rather than providing a high PTFE condition. The principal advantages of PTFE particles exerted on the ternary Ni–Cu–P composite coating refer to the characteristics of no adhesion, as well as better corrosion resistance. Therefore, the Ni–Cu–P-PTFE composite coatings can be helpful for the bourdon tube heat exchanger and surface of flexible equipment.

Distributed fiber-optic pressure sensor based on Bourdon tubes metered by optical frequency-domain reflectometry

We report a distributed fiber-optic pressure sensor based on Bourdon tubes using Rayleigh backscattering metered by optical frequency-domain reflectometry (OFDR). In the proposed sensor, a piece of single-mode fiber (SMF) is attached to the concave surfaces of Bourdon tubes using a thin layer of epoxy. The strain profiles along the concave surface of the Bourdon tube vary with applied pressure, and the strain variations are transferred to the attached SMF through the epoxy layer, resulting in spectral shifts in the local Rayleigh backscattering signals. By monitoring the local spectral shifts of the OFDR system, the pressure applied to the Bourdon tube can be determined. By cascading multiple Bourdon tubes and correspondingly attaching SMF sections (i.e., a series of SMF-modified Bourdon tubes), distributed pressure measurements can be realized. Three Bourdon tubes are employed to demonstrate the proposed spatially distributed sensing scheme. The experimental results showed that linear relationships between spectral shift and pressure were obtained in all three SMF-Bourdon tubes (i.e., at three spatial locations). It is expected that the proposed sensing device, the SMF-Bourdon tube, can be used in applications where distributed/multipoint pressure measurements are needed.

Design Analysis of Wireless Pressure Measurement by Integrating Surface Acoustic Wave Sensor With Bourdon Tube

A modified wireless pressure measurement system using Bourdon tube as a primary sensor has been proposed in this paper. The modification is done by integrating the surface acoustic wave (SAW) sensor with the Bourdon tube. The sensor is placed on the surface of the Bourdon tube which measures the stress level of the Bourdon tube for different applied pressure. The response of the SAW sensor is calculated in terms of shift in the resonant frequency which is equivalent to the applied pressure. The central resonant frequency found during simulation at 0 PSI is 433.1 MHz. The simulated response gives a change in linear frequency shift with respect to the change in pressure.

Effects on calibration values of quarts Bourdon-type pressure transducers caused by density of pressure medium

We have found that the calibration values of a quartz Bourdon-type pressure transducers are affected by the kind of pressure medium and the setting conditions. The effect comes from an additional gravitational force arising from the weight of the pressure medium inside a Bourdon tube at sensing element. In this study, the amount of the effect was evaluated quantitatively by comparing the calibration values of the pressure transducer at upward and downward settings. To investigate the relationship between the effect and the density of pressure medium, the amount of the effect was evaluated at pressures up to 100 MPa for using nitrogen, helium and argon. The amount of the effect has a linear relationship with the density regardless of the pressure and the kind of pressure medium.

Laboratory Simulation and Measurement of Instrument Drift in Quartz-Resonant Pressure Gauges

Seafloor pressure gauges are used in marine geodesy to detect vertical displacement of the seafloor. Instrumental gauge drift is often larger than the sought after geophysical and oceanographic signals. We performed a 12 month laboratory test on two new methods that aim to reduce pressure gauge drift in Paroscientific Digiquartz and other pressure transducers. In one method, a reference quartz oscillator (RQO) is installed adjacent to but isolated from the Bourdon tube whose stress is measured by a vibrating quartz force transducer. In another method, the pressure gauge is periodically connected to accurately measured atmospheric pressure as a reference to allow drift calculation. We found that the RQO is not a good predictor of gauge drift. However, determining drift by periodic exposure to atmospheric pressure is effective. These drift estimates were compared to estimates determined with an absolute piston gauge calibrator; the average difference between drift rates of the two methods is 0.00 ± 0.05 kPa/year. Finally, we tested the stability of the quartz clocks used in the Paroscientific electronics and found that they are not a significant contributor to drift.

A novel technique on MZI based electro-optic type pressure transmitter using modified bourdon tube

Bourdon tube, an indicating type pressure measuring instrument is used as a local indicator and display unit. Hence a special technique is needed to transmit and to display the reading of a bourdon gauge at remote location. In this paper, a modified bourdon tube has been proposed which is capable to transmit the measured pressure information via optical domain by employing the method of electro-optic effect in Mach–Zehnder interferometers (MZI). Modification in the bourdon tube is done by fabricating an inductor coil to the arm of the bourdon tube. The movement of the bourdon tube is measured in terms of the voltage drop across the inductor. Voltage drop measured by digital voltmeter, across the inductor coil linearly increases (2.29V–2.38V) as pressure increases (0PSI–40PSI). Amplification of the voltage drop across the inductor coil is done by instrumentation amplifier and the Optical transmission is done by the electro-optic modulation with the help of the MZI. The voltage required for electro-optic modulation is achieved by the signal conditioning circuit which is connected with the instrumentation amplifier. It has been observed that the variation in the pressure is directly proportional to the intensity modulated light signal which has very good linearity and repeatability. The required theoretical equations along with the experimental results are reported and compared in this paper.

Basic Knowledge and Skills for Adjustment and Application of Bourdon Tube Type Pressure Gauge

This paper analyzes the failure phenomenon and adjustment skill through the basic introduces of the principle of Bourdon tube Type pressure gauge. The detect of bourdon tube type pressure gauge was discussed to make sure the accuracy of the data measured by bourdon tube type pressure gauge to colleagues as reference. Bourdon tube type pressure gauge has already widely used in the maintenance of the ground equipment, and pressure gauge performance stable and reliable quality will influence aircraft maintain quality. The correct use and debug the bourdon tube type pressure gauge determine to the measure of pressure gauge. We should analysis on the structure and principles of bourdon tube type pressure gauge and the cause of the problem, to give the repair method.

Anti-Bourdon tube pressure gauge

Abstract A novel pressure transducer is investigated in this paper, which works on an anti-Bourdon tube (ABT) principle due to dual effect of differential expansion of the tube at various points and the end moment induced due to asymmetry of cross section. Different materials such as rubber, stainless steel, nickel, brass, copper etc. and different geometries of tubes and bellows are investigated experimentally and analysed using theoretical formulation and Finite Element Analysis. Prototypes of the pressure gauges using rubber, nickel and stainless steel bellow as sensing elements are fabricated and tested. The proposed sensing element will behave similar to the asymmetric metallic tubes but will have about three times higher flexibility and grater rate of expansion and deflection under internal pressure. Comparative results with the existing Bourdon pressure gauge show that the ABT pressure gauge is simple in construction, economical for fabrication, reliable and promising pressure gauge in future. At the end, various design configurations of the pressure sensing element are discussed. By proper selection of geometry, materials and manufacturing of the asymmetric metallic tubes or bellows as sensing element, an ABT pressure gauge can be fabricated to measure pressure ranging from low to high or very high pressures for various potential applications which is not possible using Bourdon tube pressure gauge.

Design and Development of Soft Gripper System for Handling Non Rigid Materials

Automation and flexible system development are an imperative need of current Industrial applications. End effectors are mainly used to achieve many tasks in material handling. There are varieties of grippers/end effectors developed and used for multiple purposes in automation fields. The conventional end effectors mainly used for pick and place the products like hard, soft, variable shape and very thin materials using various principles. But there is a need in fluid transfer through flexible end effectors. We proposed a pliable end effector which has been developed under Bernoulli's principle. The focus of studies in fluid handling course is on the methods, mechanical equipment, systems and related controls used to achieve the functions like movement, quantity, time, space, and control of the end effector. To design and develop a novel dupe for fluid transfer by means of toothed quadrant sector, windup coil spring and bourdon tube. This operates with mechanical linkage mechanisms and attractive-suction forces are applied to the fluid surface. Then the end effector suck and release fluids automatically under the mechatronics control systems. This experiment has been carried out with different viscous fluids and the results compared with analytical results.

A Modified Technique of Flow Transducer Using Bourdon Tube as Primary Sensing Element

The pressure head at a point inside a flowing fluid through a pipeline decreases with the increase of flow rate according to Bernoulli's equation. The measurement of flow rate by measuring this pressure is not generally used since decrease of pressure is very small compared with static pressure at no flow. In this paper, a modified differential inductance-type technique has been developed to measure the flow rate of a fluid by measuring only this change in pressure without using any obstruction in the pipeline. A differential inductance-type pressure transducer using two identical Bourdon tubes as the primary sensing elements, has been designed and developed to measure the small decrease of pressure due to flow of fluid in a horizontal pipeline. The transducer has been used to measure the flow rate of tap water through a pipeline. The basic theoretical equations describing the operation of the transducer have been derived. The transducer has been experimentally tested and the experimental results are reported in this paper. The experimental characteristic is found to follow the theoretical equations with good repeatability.

A Fiber Bragg Grating Pressure Sensor and Its Application to Pipeline Leakage Detection

The fiber Bragg grating (FBG) technology has been rapidly applied in the sensing technology field. In this paper, an FBG pressure sensor is designed and implemented to detect the leakage of prestressed concrete cylinder pipe (PCCP). The pressure sensor is mainly based on a Bourdon tube with two FBGs bonded on its outside and inside surfaces, respectively. The measurement principle and simulation analysis results are described. The wavelength shift difference of the two FBGs is utilized as a pressure sensing signal, the sensitivity is enhanced, and the temperature cross-sensitivity is compensated. Experimental results indicate that the measurement sensitivity is 1.414 pm/kPa in a range from 0 to 1 MPa, and the correlative coefficient reaches 99.949%. This kind of pressure sensor is effective to quasi-distributed measure and online monitor pressure of gas or liquid in industry and manufacture fields.

The Structural Design Research of Bourdon Tube

Bourdon tube has been widely used in the fluid testing so far, and this paper introduces the chemical and physical behaviors of beryllium bronze QBe2.0 detailedly which mainly makes up bourdon tube; It analyzes the influences of elastic limit in bending on bourdon tube the chemical elements and coating technology bring; Simultaneously, it focuses on the design of the base of tube and the assembly body, points out the location of bourdon tube in bourdon tube pressure gauge; and the design of this paper can guarantee the normal work of bourdon tube in the sealed environment through the theory and practice. In the process of gauge fabricating, appropriate application of bourdon tube is very important.