Heat exchanger equipment for heating or cooling bulk solids including heating conveyors, cooling conveyors, batch heaters and combined heat transfer and mixing.

AJAX Heat Transfer Equipment

AJAX produce a range of heat exchanger machines for both batch and continuous heat transfer requirements. AJAX heat exchangers are generally designed for particulate materials (powders and granular solids) but have also been used for thick slurries and pastes. A range of cooling or heating mediums can be accommodated including water, water/glycol mixtures, steam, oil and hot or cold gases. External heating elements can also be incorporated into the systems we provide.

Applications and industries include chemical processing, food and beverage production, nuclear power, biomass processing and waste to energy plants.

Our Range of Heat Exchanger Equipment Includes:

• Heating and Cooling Conveyors.


• Heated or Cooled Continuous Mixers.


• Heated or Cooled Batch Mixers.


• Heated Processing Equipment.

Heating and Cooling Conveyors.

These machines consist of a tubular or ‘U’ trough casing with a jacketed exterior and a hollow shaft conveying element with either rotary unions at each end or a single rotary union with a syphon tube. Heat transfer medium is pumped through both the jacket and the conveying element. Our heat transfer conveyors have special designs of flights and paddles that homogenise the material as it is conveyed thus giving better heat transfer and a more even distribution of heat. The capacities of the conveyors depend on the heat transfer characteristics of the product and the difference between the required output temperature of the product and the inlet temperature of the heat transfer medium.

Heated or Cooled Continuous Mixers.

These machines consist of twin mixing elements, either paddles or ribbons, overlapping in a double ‘u’ trough casing. Continuous mixers generally involve a limited amount of heat transfer as the work (machine speed) required for efficient mixing limits the dwell time of product in the machine, nevertheless, heated or cooled jackets and mixing elements are useful for maintaining temperatures of products that need to be above or below ambient during the mixing process. These machines can have capacities of up to 100 cubic metres per hour but are more generally used in the 1 to 8 cubic metre per hour range.

Heated or Cooled Batch Mixers.

These machines consist of a jacketed vessel and with an agitator mechanism. Heat transfer medium is passed through both the jacket and the agitator. These mixers can be used to simultaneously mix and heat different batch ingredients or can be used to heat a single product with the agitating element promoting thermal homogenisation and optimum heat transfer. Volumetric capacities can range from a few litres per batch up to ten cubic meters per batch.

Heated Processing Equipment.

This class of equipment usually involve high temperatures and sometime high pressures and can be used to induce chemical reactions, evaporate moisture, induce a phase change, sterilise a product and facilitate other heat dependant processes. Heating can be via a heat transfer fluid, usually oil, trace heating or direct heating using tube furnaces. Process temperatures of up to 800° can be accommodated. AJAX have produced heated processing equipment on both a commercial and pilot plant scale.

AJAX Heat Exchanger Design

Heating granular materials whether continuously or as a batch requires a degree of mixing. The elements that contribute to the mixing are also the elements that do most of the heat transfer work and so, are designed to combine a large surface area with an effective blending action.

Where a heat transfer fluid is involved, turbulent rather than laminar flow is preferred for optimum heat transfer, however, with our equipment a true turbulent flow regime is rarely achievable. AJAX, therefore, incorporate a series of baffle plates in the fluid flow paths to induce a degree of localised turbulence and to disturb the fluid boundary layer.

AJAX calculate the size and geometry requirements of heat exchangers based on the fundamentals of heat transfer aided with historical data from our previous work which allows us to accurately predict the heat transfer coefficients to be applied to each particular type of equipment.

For freezing or flash chilling of bulk solids see AJAX Cryogenic Coolers

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