Study of Blockage Diagnosis for Hydrocyclone Using Vibration-Based Technique Based on Wavelet Denoising and Discrete-Time Fourier Transform Method

Abstract

Hydrocyclones are extensively known as important separation devices which are used in many industrial fields. However, the general method to estimate device performance is time-consuming and has a high cost. The aim of this paper was to investigate the blockage diagnosis for a lab-scale hydrocyclone using a vibration-based technique based on wavelet denoising and the discrete-time Fourier transform method. The results indicate that the farther away the installation location from feed inlet the more regular the frequency is, which reveals that the installation plane near to the spigot generated the regular frequency distribution. Furthermore, the acceleration amplitude under blockage degrees 0%, 50% and 100% fluctuates as a sine shape with increasing time, meanwhile the vibration frequency of the hydrocyclone rises with increasing throughput. Moreover, the distribution of four dimensional and five non-dimensional parameters for the time domain shows that the standard deviation, compared to the others, reduced gradually with increases in blockage degree. Thus, the standard deviation was used to evaluate the online diagnosis of the blockage. The frequency domain distribution under different throughput reveals that the characteristic peaks consisting of the faulty frequency and multiple frequency were produced by the faulty blockage and the feed pump, respectively. Hence, the faulty peak of 16–17 Hz was adopted to judge the real-time blockage of the hydrocyclone, i.e., the presence of the characteristic peak marks the blockage, and its value is proportional to the blockage degree. The application of the online monitoring system demonstrates that the combination of the time domain and the frequency domain could admirably detect the running state and rapidly recognize blockage faults.

Analysis and Prediction of Influencing Parameters on the Coal Classification Performance of a Novel Three Products Hydrocyclone Screen (TPHS) Based on Grey System Theory

“…In this research, the mass flow ratio of solids, i.e., solid recovery, for each product stream was calculated by Equations (1)-(4) according to the least-squares method (LSM) [29]. So as to eliminate the effect of the bypass to underflow [30,31], the corrected partition curve was conducted using Equations (5) and (6). To evaluate the performance of TPHS, Hancock classification efficiency (HE) and the imperfection (I) was obtained by Equations (7) and (8), respectively [32][33][34], and the corrected cut size of the partition curve (d 50c ) was gotten according to its definition (see the details in the annotation after Equation (8)).…”

“…According to the high throughput, low cost, flexible operation and so on, hydrocyclones are now widely used in mineral, chemical, environmental, and some other industrial processes [1][2][3]. The conventional hydrocyclone (CH) includes one tangential feed inlet and two axial product outlets, i.e., smaller underflow at the bottom and bigger overflow at the top to discharge coarser and fine particles, respectively [4,5]. Nevertheless, on the one hand due to the inherent disadvantages (like fish-hook effect or unsatisfactory efficiency [6,7]), on the other hand owing to the new trendies (like the reducing processed particle size [8,9]), the hydrocyclone performance is partly weak, even the device cannot be adopted in some industrial process cases.…”