ROTARY DRUM DRYING AND COOLING UNIT

Insulated Cabin, Smart Moisture Regulation and Integrated Shock-Cooling Station

A high-technology drying and shock-cooling system for lowering, to ideal standards, the free and internal moisture held in any grain, flour, semolina and various food raw materials by fully natural, controllable thermal methods — without any harm to the product’s molecular and physical structure.

Especially in maize-flour and -semolina processes, it fully eliminates the high-moisture problem that, after packaging, leads to mould, clumping, weight deviations and, above all, aflatoxin formation and returns. It extends the products’ shelf life, ensures food-standard compliance and gives the product high commercial added value.

Dimensional Smart Process Parameters

The system is optimized by the operator according to raw-material characteristics and target moisture index, operating with full synchronization of desired recipes:

1. Feed Flow (Inlet Feed Rate): The volumetric flow of product entering the drum is set by the feed screw under frequency-inverter control.

2. Drum Rotation Speed: The tumbling and homogenization speed of the raw material is controlled via motor-speed control.

3. Drum Tilt Angle: By adjusting the horizontal tilt angle of the drum, it sets the linear advance to the outlet by gravity and ensures precise residence time inside.

4. Cabin Set Temperature: The air temperature inside the insulated cabin is measured by precise sensors and held constant at the target drying threshold.

5. Cabin Saturated-Moisture Level: The moisture passing from the product into the air is tracked in real time by advanced humidity sensors and exhausted from the line by fans according to the set value.

WORKING PRINCIPLE

Speed-adjusted helical flow and homogeneous tumbling — controlled feed and internal thermal process: the product is delivered into the closed space by a speed-adjustable feed screw; inside the cylindrical drum, made entirely of chrome-nickel stainless steel, the product is continuously rotated and tumbled by special angled inner paddles, moving homogeneously toward the outlet on the horizontal axis.

Sustainable heat recovery in the insulated cabin — closed-circuit thermodynamic drying: the rotary drum is enclosed in a fully insulated cabin; the hot air produced by electric heaters or a hot-water heat exchanger is forced onto the drum surface by a medium-pressure fan; the cabin air is circulated in a closed circuit to recover energy, while the moisture-saturated air is automatically exhausted on a sensor signal.

Thermal shock-cooling, shelf life and product quality — chiller-driven vibratory shock-cooling: the product leaving the dryer at high temperature is taken into the chrome-surface shock-cooling section; at this station, powered by an industrial chiller, the product is rapidly cooled without disrupting its structure and made ready for packaging.

KEY ADVANTAGES

- High, optimised energy efficiency: The heat-recovery closed-circuit design prevents thermal energy from escaping outside, minimizing energy use and lowering operating costs.

- End to aflatoxin risk and primitive drying methods: It fully ends the primitive methods of spreading product over large areas, open to outside infection, to try to lower moisture by 1–3%; on fully closed, hygienic chrome surfaces it prevents aflatoxin formation.

- Modular, flexible and customisable industrial design: It offers different size options from small plants to giant industrial complexes; owing to its modular chassis it is extremely easy to integrate into existing flour-semolina production lines.

- Low-moisture (6–7% RH) solution for international markets: It meets the food-standard-compliant production of industrial producers requiring very low, stable moisture of around 6–7% in the raw material (such as instant-soup makers).

- Sectoral application areas and process performance: Grain and flour sector — stable moisture reduction in full compliance with food regulations; capacity regime — optimized with inlet product, speed, and tilt parameters; moisture-reduction degree — net 2% RH - 3% RH net moisture-reduction power; cooling-area geometry — chrome-surface vibratory-flow shock unit; hot-air thermal source — Electric Resistance or Hot-Water Exchanger systems per customer request; system metallurgy — all product-contact surfaces and cylinders entirely of CR/NI (Chrome/Nickel - Stainless Steel).

ENGINEERING NOTE

The rotary-drum drying-and-cooling unit is a refined process station uniting thermodynamic balance and food-safety criteria under a single automation roof in flour and grain technologies. The kinematic flexibility of the drum’s mechanical tilt angle and inverter-supported rotation speed brings the material’s flowability in the drum close to a liquid phase, so each flour particle or grain kernel contacts the hot-air curtain for an equal time and dries homogeneously. The chrome surface of the shock-cooling section, fed by chiller energy, provides a sharp thermal transition, maintains the hygroscopic balance and prevents post-packaging sweating and weight losses.