ATEX Corrosion Resistant Fans in Asphalt & Cement Production
Corrosion resistant ATEX fans are required through many processing stages of cement and asphalt production. Large duty fans are typically used to enhance combustion, exhaust toxic gases, or for material handling. Selecting the correct specification of fans is crucial for both safety and ensuring the overall efficiency of the plant, for example, air supplied to fuel combustion helps to maximise the end product yield meet high demands. This is especially fundamental in an ecomony focused on increased housebuilding and supporting infrastructure development.
Some processes undertaken during the manufacture of cement and asphalt lead to the by-production of flammable fumes and vapours, or combustible dust particles which if left undiluted or unexhausted, will accumulate in the air. Ventilation systems used to dilute or exhaust these fume, therefore maintain a safe and comfortable working environment for operators and prevent possible high risk areas. ATEX fan selection is a difficult and niche task for those specifying ventilation for applications handling potentially explosive or combustible materials. Fan suppliers have extensive ATEX knowledge to enable them to recognise the requirements, but DSEAR specifications must come dirctly from the user to ensure no assumptions are made. In line with the ATEX guidelines for explosive atmospheres, ATEX fans offer spark proof protected to prevent the risk of it being a source of ignition from sparks and arcs within the motor, or from friction, and therefore their construction and properties are specifically designed to meet the correct ATEX requirements. Corrosion of fans, moving parts and other components is a significant problem in the cement and asphalt industry due to the aggressive nature of the toxic fumes and vapours present. Material compatibility is assessed during the fan specification process by the technical team, providing longevity to the fan. Our corrosion resistant ATEX fans are suitable for gas zone 1, gas zone 2 and dust zone 22.
The Cement Production Process
To initiate the process of cement manufacturing, raw materials such as limestone, sand and clay are extracted and sent to the cement plant where they are crushed and milled into fine powders. The powders are combined and then sent through two kilns, where it is first pre heated to burn off impurities and then travels through an extremely high temperature kiln where the CO2 is removed from the limestone and the powders are converted into a solid product referred to as clinker. ATEX explosion proof fans operate safely in these zones and provide efficient cooling through the kilns, preventing overheating to extreme temperatures which could cause damage to components.
The clinker, otherwise referred to as ‘Raw Meal’, is then transported by air supply from material handling fans, along with any gases, to the next stage of the process where it is then ground to a fine powder and cooled in a tube or ball mill. Cooling fans are required at this stage to blow air into the cooler which significantly reduces the temperature of the product before it can be conveyed for packaging and dispatch. Inefficient cooling fans can lead to poor quality product and damage to conveyor systems.
The Asphalt Production Process
Asphalt cement contains a mixture of asphalt, aggregates such as gravel, sand and crushed rocks and bitumen, a binder that holds the aggregates together. At the first stage of asphalt production the aggregates need drying as quickly as possible in a drying burner. ATEX fans are required to provide a consistent and reliable airflow into the burner to enhance the temperature of the boiler and speed up the drying process. The aggregates are then mixed with hot bitumen which is stored in preheated tanks to maintain temperature. Another issue that needs to be controlled with cement and asphalt production is the generation of air pollution. ATEX exhaust fans, integrated into dust collector systems, work alongside filters, to capture fine dust and toxic air particles through a set of filters to help maintain low emissions.
To discuss your fan requirements and get help with ATEX fan selection, contact one of our fan integration specialists on 01782 349 430 or speak to our technical team via our live web chat in the lower right of the screen.