Newly constructed basement reduces vibrations

University of Thessaloniki, AGET Heracles, Lafarge Group

Bouzakis et al.

1 Basic dimensions of the cement mill

Bouzakis et al.

2 Top view of the mill driving units

3 The housing basement of the driving pinions

4 Vibration measurements of the pinions’ shaft housing, in the region of the fixed bearing, time signal during mill start up (from zero to full mill speed)

5 3-D model (a) and load distribution (b) of the cement mill

6 Deformation (a) and equivalent stresses (b) of the mill under the gravity loads

7 Side and section view of the existing pinion bearings’ housing basement

8 Eigenform at the critical eigenfrequency of 59.8 Hz

9 3-D view of the mill structure, focused on the V-beam, connecting the two pinion bearings’ basements

10 The redesigned lower pinion bearings’ housing basement, with higher concrete block

11 The FE model of the lower pinions’ shaft housing basement

Tab.1 Vibration measurements results on the original and redesigned pinion shaft bearing’s housing

The Halkis cement plant of the AGET Heracles General Group S.A.

Calculations using the finite element method (FEM) provided a significant optimization to the basement of cement mills. Operation-related vibrations can be reduced in this way.

Introduction

The dynamic behaviour and thus the operational reliability of large mechanical installations such as cement mills can be strongly affected by the basement of their driving units. Increased vibrations, mainly in the region of the two pinion girth gear housing basements of the double mill drive were measured during the operation of a cement mill in the Halkis plant of Heracles General Cement Co (Lafarge Group). These led to excessive damages to the tooth flanks of the pinions. The pinions were replaced without avoiding the intense vibrations in both pinion housings. To detect the...