Robust & versatile – the ONEJOON rotary kiln

Furnace head with modular ports for integrating various types of product feeding equipment.

Here: Filling of the furnace via water-cooled charging conveyor screw. Frequently used alternatives are vibratory conveyors or simple conveyor chutes.

The inlet area represents the first system boundary to the process chamber and is usually designed with a furnace head and seal. In order to meet the increasingly high demands for tightness, we rely on ONEJOON'S specially developed, patented, technical gas- and dust-tight sealing system.

For convenient maintenance work, the components in this area can be designed in a mobile way to better access the drum and some of the wearing parts. Furthermore, connections for process control and monitoring are installed here. The required measuring devices, instruments, and other "peripherals" are selected according to customer requirements.

Temperature: Standard solutions for T ≤ 1200 °C and customized solutions for T > 1200 °C

Material: stainless steel, Inconel, centrifugal casting, advanced materials (quartz glass, carbon-based)

The rotary tube is the heart of the kiln. Since it integrates the function of heat and mass transfer, it is often the only moving element of the kiln. Its robust design enables the thermal treatment of various products with differing mechanical and chemical properties. Thus, rotary kilns are used for powdery educts, solids, and viscous suspensions.

In many industries, the rotary kiln's simple operating principle is confronted with high demands on material properties and behavior. Thus, a wide variety of phase transformations, chemical reactions, and heat and mass transfer processes have to be carried out reliably, without exceeding the tube's critical material values or causing unwanted reactions between the tube and the material bed.

To ensure product quality at maximum plant safety, ONEJOON focuses on application-specific and customer-specific tube materials, geometries, and process parameters. Thus, inclination angle, speed, tube internals, and filling degrees are designed according to customer specifications.

ONEJOON rotary kilns can be designed for temperatures up to 1,200 °C. For special applications, temperatures up to 2,000 °C are also possible. Heating is realized either by electric heaters, gas burners, or an upstream combustion chamber.

We deploy an integrative system to optimize the entire plant's energy efficiency, thus considering increasingly strict limits, regulations, and growing environmental awareness. This is done by improving the design - based on mechanical and fluidic simulations - as well as operating more efficiently - by using heat exchangers, insulation, and secondary fuels.

The rotary drum furnace's heated area is enclosed by the kiln body, an outer housing, and a refractory lining. The furnace body and housing are made of steel or heat-resistant sheets. The refractory lining often consists of heat-resistant fiber insulation that allows surface temperatures below 60 °C. Alternative insulation materials such as vacuum molded parts or stones can be used in a complementary way.

Depending on the value-added chain, the product must be cooled before being transferred to the next process step or stored. In principle, various types of media can be used for cooling. In industrial practice, however, an air or water-cooled system is the rule. A combination of both concepts is also possible. ONEJOON uses a cooled drum or other indirectly cooled conveying systems, such as a vibratory conveyor, depending on the application.

The furnace is mounted on a base frame to reduce external shocks and achieve maximum stability. By utilizing discrete or continuous mechanisms, the frame can be adjusted in height and inclination. On customer request, this can be automized using a spindle lifting system.

Continuous and trouble-free drum rotation is safety-critical due to the high temperatures and the resulting drum tensions. For particularly critical processes, ONEJOON relies on diversified redundancy, using secondary engines. An electric motor with a chain hoist generally functions as the main drive.

The outlet area is the last system boundary between the process and heating room and the environment. The product discharge channel is an additional component that discharges the heat-treated product from the process area. Depending on the process, this can be done via simple conveyor systems or highly complex systems, including atmosphere exchange and emergency discharge for products with deviating product quality.