Measurements / Rotary Kilns

Kiln cold alignment measurement

The alignment can also be done with cold kilns and, in order to do so, the production has to be stopped and should be done during scheduled shutdowns. It is advisable to do it once a year.

Advantages:

• Is a high precision measurement.
• Más económica que la alineación en caliente.
• Permite realizar un chequeo en paradas programadas.

Desventajas:

• No es un resultado del horno en regimen.
• La deformación de llantas y rodillos tienen una mayor incidencia en el resultado.

Topografía interna de casco de horno

Se realiza un plano Topográfico del Horno, con el cual se puede visualizar perfectamente las deformaciones del casco. Esta medición sirve para analizar causas de caída de refractario, sobre todo en lugares que desde el exterior no son accesibles, como en las zonas debajo de las llantas.

Esta medición se realiza con el horno parado y sin refractario.

Kiln’s external topography

This measurement is very useful because it allows to define the state of the kiln’s shell, which determines the balance of tyres, rollers and drive system.
We also measure the roller shaft bending, so that the existence of either, mechanical or thermal crankshafts in the kiln can be detected. Once the magnitude and localization of the centers in successive sections of the kiln are determined, the methodology for this
All measurements are made with laser from the outside of the kiln during its rotation.

This measurement is important becouse::

• Analyzing this axis, we calculate the run out (its angle of occurrence), eccentricity and ovality of the kiln’s shell in the measured sections.
• It also shows the local deformations (hot spots) of the shell.
• This information allows planning repairs in most affected areas.

Shaft bending measurement of kiln support roller

Usually, deformations in the kiln’s shell or tyre wobbling, generates unnecessary and excessive forces on the rollers, reducing its service life and even causing roller shafts cracks and hot bearings. This means high reparation costs, and high expenses in terms of production loss, caused by kiln’s unscheduled shutdowns. That is why this measurement is presented as a valuable tool to identify the magnitudes of the forces supported by each roller and, consequently, it defines the course of action to reduce this stress.

This measurement makes it possible to diagnose the variations of the roller’s shaft bending, the angle of occurrence, and the deformations of the rolling surface.

Electronic shell test

The lifetime of the refractory lining is substantially influenced by the mechanical condition of the rotary kiln. This is to say, by the distortion produced inside the shell in every turn.

This measurement determines the degree of deflection of the shell as the kiln rotates, indicating the shell’s ovality degree, and the stress distribution among rollers of the same pier. High ovality values lead to a reduced refractory service life.

Measurement of spatial position of axis of the supporting rollers

The position of the rollers is extremely important for the behavior of the kiln. The kiln’s movement not only depends on the rollers position, but it also has an impact on the girth gear, pinion, and axial thrust roller.

In order that the supporting rollers have a convenient thrust, they must have the same slope as the kiln’s axis, but they also have to be, parallel to each other, and with an adequate skew. Otherwise antagonistic forces might be generated, resulting in overheating of bearings, compromising its service lifetime. It can also produce deformation of rollers and tyres.

Ésta medición permite definir:

• Vertical position of the roller shafts (slope). They should be compared with the kiln’s slope and the necessary corrections should be defined.
• Horizontal position of the roller’s shafts (Skew), through which the necessary adjustments for an adequate alignment in the kiln’s thrust can be planned.

Rollers chassis level measurement

As a complementary measurement, it is useful to measure the chassis level of the rollers bearings as the piers movements usually have an impact on their angle.

This measurement is significant for the purposes of comparing the slope of the chassis with the theoretical slope of the kiln. If the levels are inadequate, they can generate an inappropriate thrust of the rollers.

If necessary, shims are calculated to achieve the leveling position.

Drive system measurement during normal operation (no stop required)

Wobbling:

Run Out:

All these measurements are made with computerized equipment, using non-contact measurements which allows a diagnosis of the equipment under normal working conditions, obtaining real working values without affecting production.

Kiln’s tyres migration measurement.

OBOURG method:

Measurement of diameters of tyres and supporting rollers.

With the purpose of analyzing the need of re surface tyres and rollers, we count with computers that allow the measurement of circumferences with the kiln in motion.

According to the results of this measurement, our company analyzes the wear or damage of the rolling surfaces, and determines if grinding is necessary.

Roller and tyre topography measurement.

This a laser measurement, performed during normal operation of the rotary calcinator. This method has higher accuracy (0,02 mm). The result is a 100 mm * 50 mm topographical mesh of the rolling surfaces.

Tyres Wobbling and run out measurements

Tyre wobbling:

Tyre Run Out:

Additional measurements

The previous measurements are complemented with the following ones to achieve a more accurate diagnosis. :

• Temperature of shell, tyres, roller bearings, and girth gear
• Distance between roller’s centers
• Girth gear’s root clearance and backlash

Visual inspection:

• Contact between rollers and tyres. Thrust roller
• Shims and retaining blocks.
• Inlet and outlet seals.
• Girth gear back lash and root clearance.