Vibration of the steel frame of the primary sand classifier

Josef Soukup,Jan Skočilas,Blanka Skočilasová,M Vasko,P Kopas,O Štalmach,V Baniari,A Sapietová,M Handrik,M Blatnická,M Sága,L Jakubovičová

doi:10.1051/matecconf/201815705020

Abstract

Article deals with the presentation of measurement that have been carried out on the steel frame of the primary sand classifier. The aim of the investigation was to identify the sources of the abnormal vibration of the frame. The vibration significantly reduces the effective performance of the classifier. The frame anchorage has been stripped out from concrete footing by these vibrations. The measurement of dynamic properties of the frame were performed. The displacements of the particular trusses have been experimentally investigated by accelerometers. The tensile test were performed in the places of expected maximum amplitude of the vibration. Based on the experiment results and new design calculation of the steel frame (truss construction), the new construction design was developed and improved by frame reinforcing. The new designed construction was investigated by vibration measurements again. The acceleration and total amplitude of particular trusses were recorded. The steel construction of the supporting frame has frequencies in range from 13.07 to 13.10 Hz. The significant enhancement of the noise and vibration of the main bearing have been observed during the classifier operation. The system of precautions was proposed to improve operation of the classifier and after realization the classifier run with no limitation.

Highlights

The reduction of the maximum amplitude of the vibration of the rigid construction and related noise is an optimization process which can be solved by several methods, e.g. experimental or numerical [1]
The measurement results indicate that the frequency of the entire structure oscillation ranges from 13.07 to 13.1 Hz in all measurement cases, which demonstrates that all measurements are commensurable
The steel structure of the CVB 2661 III classifier was made stronger, which definitely reinforced the entire structure, we have reservations about its structural design, which was confirmed by the measurements

Summary

Introduction

The reduction of the maximum amplitude of the vibration of the rigid construction and related noise is an optimization process which can be solved by several methods, e.g. experimental or numerical [1]. Usually the customer needs the analysis and improvement of the system in very short period In such cases there is no time for numerical study and its validation. The excavated gravel sand is conveyed by the 800 mm wide and 40 m long belt conveyor to a METSO CVB 2661 III spraying coarse vibrating classifier; the sand travels from the classifier to a two-shaft knife washer. The coarse classifier makes high vibrations, which are transmitted by the steel structure to the foundations and further to its surroundings. The facility operator requested the measurement of the steel structure and casing and mechanism vibrations of the coarse classifier. Empty coarse classifier placed on the steel structure weighs 12,640 kg, material inside the classifier weighs 1,500 to 2,000 kg (depends on the filling of the classifier)

Methodology

Experimental examination of reinforced steel structure

Conclusion