Five fundamental features
The following design features lay the foundation for the cement cooler’s superior performance:
1. Separate clinker conveying and cooling systems
Unlike other cooler designs, the FLSmidth Cross-Bar cooler separates the clinker conveying and air distribution systems. Reciprocating cross bars fitted above the stationary air distribution system effectively convey, mix and shear the clinker while at the same time preparing the clinker for efficient exposure to the cooling air. A further benefit to this separation is that gradual wear of the cross bars has no effect on cooler operation, and thermal efficiency stays high.
2. Stationary, sealed grate line
The FLSmidth Cross-Bar cooler has no movable grate plates. There is no fall-through of clinker, and no undergrate clinker conveying system or gap management of grates is required. A static layer of clinker protects the air distribution plates against heat and wear, so the plates are no longer a standard wear part.
A patented sealing design consisting of U- and C-profiles around the drive plates forms a dust trap, preventing clinker from entering the undergrate compartment. The sealing profiles extend throughout the entire cooler length, which means that during the reciprocating movement of the profiles, the ends are never exposed to wear by the clinker.
Five fundamental features
3. Self-adjusting mechanical flow regulators
Each air distribution plate is equipped with a mechanical flow regulator (MFR) that regulates the airflow via a self-adjusting orifice. This optimal principle of continuous airflow
regulation was invented by FLSmidth and helps optimise heat recuperation and distribution of air throughout the entire cooler. In turn, it enables fuel savings and few installed cooling fans.
The MFR maintains a constant airflow through the air distribution plate and clinker bed, irrespective of clinker bed height, particle size distribution or temperature. Should the restriction of airflow through one area of the clinker layer change, the MFR automatically compensates for the variations in restriction and maintains the desired airflow based on simple physics and without operator intervention.
4. Modular concept
The FLSmidth Cross-Bar cooler is designed not only for completely new coolers, but also as an upgrade for most existing cement clinker coolers. To meet these requirements, the cooler is constructed as a modular system with units of varying size.
The cross bar cooler has a fixed inlet module followed by standard units, each measuring 1.2 or 1.8 meters in width and 3.0 or 4.2 meters in length. The standard units are preassembled in the workshop to ensure high quality and swift, simple installation.
Depending on the width (1.2 or 1.8 meters), a unit includes either 2 or 3 movable frames, each of 2 grates wide. Each movable frame rests on two roller bearings and includes a drive plate that penetrates the grateline via a slot that extends throughout the entire unit length. To form a whole clinker cooler, a number of units are put together lengthwise and widthwise, and the movable frames are connected along the length of the cooler.
Five fundamental features
5. Horizontal design with optimised transport method
The cooler’s new drive mechanism is designed to obtain optimal transport efficiency. Each line of movable frames in the cooler is operated by 2 or 4 hydraulic cylinders, depending on the cooler size, and has an independent drive. While all cross bars move in a shuttle motion, the movement of each line can also be separately adjusted to accommodate diverse clinker bed conditions.
High clinker transport efficiency allows horizontal construction in order to minimise installation height or maintain overgrate and kiln hood velocities in cooler upgrades – leading
to low cost of civil work and reduced dust recirculation.
In addition, an Air-Blast Controlled (ABC) fixed inlet as standard prevents the formation of snowmen and gives an optimal start to the cooling process with a more uniform clinker layer.