Grain rolling mills are assets responsible for processing cereals in order to turn them into food suitable for animal digestion. Grain rolling takes place by passing the grain between two rollers, which can be smooth, knurled or grooved. This process crushes and fragments the grains. The nutritional value of the processed cereals is thus altered, as the protein matrix that connects and covers the starch granules is broken down, making the grains more digestible. In addition, these actives can also be used in the food industry, processing cereals for human consumption.
Types of grain rolling mills
There are two main categories of grain rolling mills: hydraulic and pneumatic. The difference between them is the drive and pressure control system used.
Hydraulic rolling mills
These assets operate by means of hydraulic systems, which are responsible for controlling the force and pressure that the rollers apply to the grain. In this equipment, fluids pumped into a hydraulic cylinder generate the pressure. In other words, pistons transfer the force to the rollers, causing continuous and uniform pressure. The main advantages of hydraulic rolling mills are the precision of control, as well as the possibility of making adjustments according to the needs of the operation.
Pneumatic rolling mills
Pneumatic rolling mills are active machines that use air pressure to apply force to the processing rolls. In this way, the pressure is adjustable, which guarantees the precision required for the process. These assets can be more compact compared to other types of rolling mills, but they usually consume more energy to operate. In addition, the production capacity of pneumatic rolling mills is lower.
Grain rolling mill components
Rolling mills are configured as follows:
- A rotary feeder;
- Split bearings where the rollers fit;
- Rolling mill made up of two sturdy, adjustable rollers, both of which can rotate or one of which is fixed;
- Automatic feed system, adjustable according to speed;
- Sealing system;
- Access doors for maintenance and inspection;
- Roller scrapers.
In the case of grain rolling mills, the rollers are the components that tend to fail the most, in this case failure due to wear. Good maintenance practices for these components include frequent cleaning, proper lubrication, adjustment and alignment, temperature monitoring and periodic visual inspections for signs of wear and other faults that could compromise grain quality.
Faults due to wear in grain rolling mills
As mentioned, wear is the most common cause of failure in grain mills. This problem usually occurs thanks to a confluence of operational factors considered normal, such as maintaining the parallelism and alignment of the rolls, uniform end-to-end feeding and proper adjustment of the roll stops. Or factors related to the characteristics of the material, such as grain cleanliness, humidity and weight.
Wear due to abrasion of the material
The composition of grain mill rolls is generally chilled cast iron, centrifuged iron alloys or solid steel forging. These materials ensure that the surface of the roll has the necessary rigidity to withstand the friction of the rolling process. Naturally, cereals have abrasive characteristics or impurities that contribute to wear. The effects of abrasive substances on rolls are evident in cases such as the rolling of rapeseed and tapioca chips, which contain abrasive minerals in their composition and accelerate wear.
Frictional wear
Another factor that contributes to wear on the rolling surface is direct contact between the metal rolls. Even though they are very resistant to accidental contact, it is not recommended to operate them without material being processed. Direct contact between the rolls can be seen in corrugations with flat tops, sharp or broken edges for rolls with grooves. In many cases, circumferential grooves or scratches on the rollers and an increase in noise are also evident.
Preventive and corrective actions
When wear is identified on the roller surface, it is not always necessary to replace the component. The roller can be subjected to a process in which the thin layers of the surface are removed with the intention of restoring the original geometry of the roller and extending the life of the component, called grinding. However, this procedure can only be carried out a few times.
For this reason, it is essential that wear is identified early, so that the failure has not yet caused deep cracks or significant loss of the roller’s surface material. To this end, continuous monitoring of the asset is indispensable.
Continuous condition monitoring of grain rolling mills
By implementing a continuous monitoring system for grain rolling mill rolls, it is possible to identify wear faults on the surface of these components at an early stage. This ensures proper maintenance and efficient monitoring of this equipment, as well as ensuring the production of high-quality products.
Dynamox’s online monitoring system enables continuous monitoring of the health indicators of grain rolling mills, helping to identify early signs of wear and potential failures in this equipment, thus helping to raise the reliability and availability levels of industrial plants.
Wireless vibration and temperature sensors
The vibration and temperature monitoring devices continuously monitor the health of the assets. In addition, they are IP66 / IP68 / IP69 and Ex certified, which ensures safe use even in hazardous areas. Using these devices to monitor rolling mills makes it possible to detect variations in the levels of vibration and temperature signals, and to distinguish these variations from normal operating patterns.
Automated collection Gateway
Data can be collected automatically using a Gateway connected via Ethernet or Wi-Fi. This allows communication with the sensors, sending the information for analysis on the Dynamox Web Platform. In addition, there is no limit on the number of sensors per Gateway, making it possible for a single device to collect data from dozens or hundreds of sensors simultaneously. The solution also includes an Ex Gateway for classified areas.
Web platform for analysis and diagnosis
Once the sensors have been applied to the asset and the Gateway has been installed on the plant perimeter, the Dynamox Web Platform and App can be configured. The tools available on the platform support maintenance teams in making more assertive decisions. Thus, it is possible to carry out telemetry analysis and identify patterns in the evolution of rolling mill failures. In addition, using the spectral analysis and correlation tools, frequency ranges and behavior shown by faults become evident.
Rely on the Dynamox solution to monitor these assets and avoid failures, downtime and accidents. Get in touch and find out more.