J. J. Silva

Non-Invasive Fast Detection of Internal Fouling Layers in Tubes and Ducts by Acoustic Vibration Analysis

The easy detection of fouling in duct systems is a persistent problem and remains a relevant demand for the chemical, oil, food, and pharmaceutical industries. The fouling process is the slow unwanted layer deposition of heavy organic and other dissolved solid materials out of transported fluids onto inner wall surfaces over an extended period of time. This work presents preliminary research results of vibrational hammer excitation for easy-to-use external non-invasive nondestructive fouling detection in pipelines and other large-scale duct systems. The main goal is the localization of inner pipe-layer formation and thickness estimation of the adsorbed material. Data were taken from the vibration variation in the presence of an inner pipe fouling layer using acoustic microphone detection. The experimental setup, achievable sensitivities, and limitations of the method are outlined.

Development of Circuits for Excitation and Reception in Ultrasonic Transducers for Generation of Guided Waves in Hollow Cylinders for Fouling Detection

This work presents circuits that are developed to excite ultrasonic transducers transmitters and to receive the coming signals of ultrasonic transducers receivers, via hollow cylinder, converted into guided waves so that this system (transmitter and receiver) can be used for fouling detection. The fouling is a problem that has been present in the chemical, petroleum, food and pharmaceutical industries. It consists of the deposition of heavy organic materials and other dissolved solids or in suspension in fluid transport system. The ultrasonic guided waves present specific characteristics and have demonstrated good results in detection of flaws in piping. The circuits are presented and experimental results discussed

Fouling detection based on analysis of ultrasonic guided waves using wavelet transform

Fouling detection is a relevant problem for chemical, oil, food and pharmaceutical industries. Fouling consists of the deposition of heavy organic materials and other dissolved solids or in suspension in fluid transport system. The ultrasonic guided waves present specific characteristics and have demonstrated good results in detection of flaws in pipelines. In this paper, the application of wavelet transform to analyze ultrasonic signals in order to detect fouling in pipelines is presented. A platform of tests has been used to emulate the fouling problem. The pipelines were used as a medium to guide ultrasonic waves and weekly measurements were used to observe the fouling process. The Daubechies 4 wavelet was applied to each measurement set. The results reveal that the variations of the energy-spectrum of the wavelet detail coefficients may provide an appropriate way to detect fouling, since it was observed that the increase of the fouling causes a notable reduction in the energy values.

Vibration analysis for fouling detection using hammer impact test and finite element simulation

The easy detection of fouling in duct systems is a persistent problem and remains a relevant demand for the chemical, oil, food and pharmaceutical industries. This work presents preliminary research results of vibrational hammer excitation for easy to use external non-invasive, non-destructive fouling detection in pipelines and other large scale duct systems. The main goal is the detection of inner pipe layer formation, and thickness estimation of the adsorbed material. Data were taken from the vibration amplitude variation in presence of an inner pipe fouling layer using acoustic accelerometer detection, combined with FE (Finite Elements). The experimental set-up, achievable sensitivity and limitations of the method are outlined.

Fouling detection using hammer impact test and wireless comunication

There is a persistent problem that continues to be a relevant demand for the chemical, petroleum, food and pharmaceutical industries. This problem is the fouling detection in systems of ducts. This work shows how the previous tests to develop a platform for detecting fouling of pipes analyze specific locations using the impact hammer test with wireless communication. To minimize the costs of maintaining the pipes and make the system feasible, this platform is practical and portable. Thus, based on previous studies and techniques already developed for the detection of fouling, there is now a portable system allowing great mobility monitoring platform.

Development of a multivariable control system on an experimental platform dedicated to the study of fouling phenomena

This paper presents the development of a multivariable control system for regulation of the physical quantities associated to the fouling phenomena on an experimental platform. This platform is considered as a two-by-two system, i.e., the voltage and current as the inputs system and the flow and pressure as the outputs system. In the Matlab scripts, the plant model was identified as a set of first-order or second-order systems with dead time. Furthermore, the Relative Gain Array (RGA) and Relative Normalized Gain Array (RNGA) were calculated to find the best pairing among loops. The diagonal and off-diagonal pairings were verified by means of PI/PID decentralized controllers, which were designed using the IMC tuning method. At last, the output control performance was evaluated using the ISE performance metric.

Vibration analysis for fouling detection using hammer impact test and ZigBee based wireless sensor network

There is a persistent problem that continues to be a relevant demand for the chemical, oil, food and pharmaceutical industries, the fouling detection in ducts systems. This work shows the early tests to develop a platform for detecting fouling in pipes and analyze specific locations using the impact hammer test based on a wireless sensor network communication. To minimize the costs of maintaining the pipes and make the system feasible, this platform is practical and portable. Thus, based on previous studies and techniques already developed for the fouling detection, there is now a portable system allowing great mobility monitoring platform at distinguished points of a pipe, improving performance measurement.

Estimated impact force for an electromagnetic hammer

This paper presents a force estimation of an electromagnetic hammer based on the principle of the magnetic force generated by the field of a solenoid that displaces its metal core to strike a structure under analysis. This technique known as the Hammer Impact Test is used as a method for vibration analysis. For the correct electronic system design a mathematical model for the hammer is needed to estimate impact force based on the input electrical current the hammer physical parameters.

Software Environments as Learning Tools for Modeling Engineering Systems

This paper describes the usage of the Matlab/Simulink and Ptolemy II environments as learning tools in the implementation of simulation models, which represent the decentralized multi-loop control system proposed for a fouling detection didactic platform. The platform is treated as a two-input two-output (TITO) plant with time delay, i.e., the voltage and current as the plant inputs and the flow and pressure as the plant outputs. In both the software environments, the control system is modeled as a cyber-physical system (CPS). Constructive details of each simulation model are shown, even as the main advantages and disadvantages of each learning tool are discussed and evaluated by engineering students.

Closed-loop control systems in a platform for fouling detection

In this paper presents the design of closed-loop control systems in a didactic platform for fouling detection. Each control loop can be distinguished by the actuator used, e.g., or control valve or frequency inverter, for adjusting the desired flow in the main tube. In a MATLAB routine were identified of plants models, it designed controllers for the systems (by the SIMC tuning method) and simulated their responses, given one set-point change and one load disturbance, both of type unit step.