The experiments that imitate wear in pump impellers were performed, in which various physical values such as outlet pressure, suction pressure, flow rate and motor current were acquired simul taneously. Three impellers with various wear amount and a normal one were tested. Similarity Based Modeling (SBM) was applied to the data for detection of the abnormality. SBM is a non-parame tric modeling method that makes a model of a certain state by sampling vectors that consists of various physical values at the ...
英字タイトル:
Investigation of multivariate analysis for detection of wear in pump impellers

A method that applies the neural network to acoustic data to detect abnormalities of horizontal pumps is proposed. In the experiments, running sound of a pump with bearing damage or misalignment was acquired from various distance while another pump in the same room was running or not running as a possible noise source. By applying the neural network to the appropriately processed frequency spectrum of acquired data, abnormality can be accurately detected regardless of the distance between the sensor and ...
英字タイトル:
Detection of abnormality of pumps by acoustic diagnosis using neural network

A new electromagnetic method for the nondestructive evaluation of electric pumps with ball bearings is proposed. A permanent magnet generates a static magnetic field and a coil of several hundred turns wrapped around it is used to pick up eddy currents induced inside rotating ball bearings and impellers. First, a method that makes use of the autocorrelation is applied to the signals of the ball bearings. A relation between the processed signals and the size of the defects in the bearings is obtained....
英字タイトル:
Electromagnetic Nondestructive Detection for Wounded Bearings and Correlation of Size of Defect and Signal

This work investigates the effective method for detecting structural abnormality such as misalignment or unbalance in rotating machines. Experiments are performed which acquire vibration acceleration data of a horizontal pump under various structural abnormality. In order to detect abnormality comparing to the normal state, feature vector is defined as a set of magnitude of rotational frequency and its harmonics of vibration signal, then change of it is evaluated with SBM (Similarity Based Modeling). W...
英字タイトル:
Study of the capability of detection of structural abnormality in rotating machines with multipoint analysis

In order to investigate effective methods to detect the abnormality of pipe supports, vibration data of piping was acquired under various operating pressure and conditions of supports. Single feature value such as RMS of vibration acceleration, vibration velocity, vibration displacement, was not always able to detect the abnormality. To make the feature value more informative, the feature vector was defined as the combination of 3 aforementioned feature value. Then the difference of feature vectors compa...
英字タイトル:
Multivariate analysis method to detect abnormality of pipe supports

The conventional design of structural components such as piping or vessels is made based on the deterministic method. In the design method, the margin of the design integrity is expressed as empirical safety factor. On t he other hand, the stochastic safety factor is calculated from data such as the standard deviation of the mate rial strength in the LRFD (Load and Resistance Factor Design) method. This method allows a rational design bas ed on the up-to-date knowledge. In this study the optimization met...
英字タイトル:
Development of Maintenance and Design Optimization Method forPiping System Based on Stochastic Theory

This study aimed to establish the method for evaluating the amount of bearing flaking in balls. We performed 5 accelerated aging tests of ball bearing s that expedite the occurance of flaking in balls and analyzed the vibraion signal. Some characteristic features for initial stage of flaking in balls are revealed such as sudden decrease of vibarion level or pulse vibration once per several revolutions of a ball. Those knowledge can be used for diag nosing the severity of bearings that indicate the existanc...
英字タイトル:
A Study on Evaluating the Amount of Bearing Flaking in Balls

A new electromagnetic method for the nondestructive evaluation of electric pumps with sliding bearings is proposed. A permanent magnet gen erates a static magnetic field and a coil of several hundred turns wrapped around it is used to pick up eddy currents induced inside rotat ing impellers. This electromagnetic nondestructive evaluation method is applied to the canned pump. By monitoring the movement of the impe ller in a canned pump, the rotation speed, the variance of the impeller position as well as th...
英字タイトル:
Study of Evaluation Method for the Amount of Wear-Out of Plain bearingswith Electromagnetic Sensor

A new electromagnetic method for the nondestructive evaluation of gears is proposed. A permanent magnet generates a static magnetic field and a coil of several hundred turns wrapped around it is used to pick up eddy currents induced inside rotating gears. This electromagnetic nondestructive evaluation method is applied to the rotating machine with gears. By monitoring the movement of the gear in a rotating machine, the wear of teeth of gear has been evaluated. ...
英字タイトル:
Study of Evaluation Method for the Amount of Wear-Out of Gears with Electromagnetic Sensor

This study evaluates the size of outer race defects of ball bearings during accelerated life testing by analyzing the signal of an electromagnetic sensor. The electromagnetic sensor consists of a pickup coil wrapped around a permanent magnet. When a conductor passes in the static magnetic field, the generated eddy currents are detected as a change of the magnetic field. The autocorrelation method is applied for sizing defects in the early phase of the damage growth and the RMS method is applied for la...
英字タイトル:
Nondestructive Electromagnetic Monitoring and Diagnosis of Damage Growth in Ball Bearings