-surface drying
Spot surface drying with minimum energy requirements

Using eddy-current technology, not only can the energy consumption during surface drying be reduced considerably – the easy and compact configuration of the system already allows you to spare money during its acquisition in comparison to normal circulation systems.

During the surface drying with eddy-current  (Liquid OFF) developed by Bauer Anlagen, the drying energy is fed to the exact place that it is most effective  – the surface of the workpiece. The surface of the workpiece is heated up within a high-frequency magnetic field in a few seconds to just over  100°C and the surface water is vaporised. Air flowing past it then takes the water vapour with it. This saves considerable amounts of energy when drying and due to the faster process, the system can be designed with smaller components, making it cheaper to assemble.

Requirements and possibilities

To be able to generate a secondary current flow on the workpiece, it must be electrically conductive. Steel is most suitable.

The physical features of high-frequency magnetic fields require as little distance between the coil and the workpiece as possible, i.e. the workpieces must be as flat as possible or rotationally symmetric. Using the modular system of the surface dryer, both the length and width of the coils can be adjusted as well as to concave and convex shapes. When installed on a handling system, the coils can also run through shapes.

Air current takes water with it

The workpieces are fed on a conveyor unit through a high-frequency magnetic field. A high secondary current flow is generated on the surface of the workpiece; when steel is used, there is an added continuous rotation of polarity. The surface of the workpiece – with the water on it – is thereby heated up, allowing the air flowing past it to take the vaporised water with it.

Air and energy consumption lowered

Only electrical current is required. The energy requirement remains low, because only the surface of the workpiece is heated up. The housing and the conveyor are only heated indirectly by the residual heat in the air.

On the strength of past experience, the energy requirement for this air technology is 70% and for heating up it is only 50% in comparison to normal hot-air dryers.

Benefits:

• No heating up time
• Fast drying
• Short cycle times
• Low operating costs
• No air conditioning
• Small, compact systems

Limitations:

• Only suitable for flat or rotationally symmetrical components
• Only suitable for iron and steel

Less and smaller components

It only takes a few seconds to heat up the workpiece to drying temperature. The housing and conveyor are only indirectly heated up; additionally, the air is only slightly above room temperature after absorbing the water. This allows small and simply constructed drying channels. Special attention must be paid to guidance of the damp-enriched air; however, this can be used to recycle deionised rinsing water.

Due to the fast drying time, the eddy-current drying channel can be designed shorter and narrower. As the air is saturated to almost 100 % relative humidity, only a smaller ventilation technology system is required. A separate cooling section, with corresponding air heater, exhaust passage, fuel line and fuel container is not required.

Easy integration

The core technology of eddy-current drying from Bauer Anlagen can be integrated on consultation into the existing design of every system manufacturer.

Enormous savings can be made in both investment and operating costs using the new system technology - as long as the geometry and material used for the workpieces are suitable for eddy-current drying and the run is large.