A very interesting project was developed for Bekaert. This is of particular interest because on the one hand much emphasis was put on energy efficiency (especially in comparison with the older dryers) and on the other hand on account of the demands on the degree of automation and the safety aspects connected to it and also the special handling demands to be solved. In this unit very thin wires are dried, which are wound on to spools. Before they reach the dryer they are rinsed. The rinsing fluid is then dried.
Assembly of the actual dryer
This concerns a pulsating air dryer with an operating temperature of up to a maximum of 300°C whose stainless steel housing is completely sealed by welding from within. The heating is effected by means of an electro-damper register, the control unit over a Thyristor actuator. A separate exhaust ventilator ensures the specific discharge of the moisture absorbed during the drying process. Large insulated service doors on the operator’s side ensure optimal maintenance possibilities. Special sound proofing measures ensure a low sound emission of < 75 dB[A].
Special energy saving measures
In order to achieve an optimal energy efficiency of the unit special precautions pertaining to a project have been taken.
- In the case in question complete high-grade heat insulation ensures high energy efficiency (surface temperature on average only 5K above ambient temperature).
- The doors at the dryer's entrance and exit are pneumatically driven and are opened only when required and ensure that a minimum of heat loss occurs.
Optimised material handling
Apart from the process engineering the material handling technology plays an important role in the dryer. The conveyor belt throughout the unit is also made from stainless-steel. The conveyor is designed for a continuous operation in the oven with up to 300°C is integrated into the drier and is aligned to the geometry and movement of the dryer doors. The hauling speed involved amounts to up to 10 metres per minute. The transfer of the product to the chain conveyor is carried out by a portal robot.
An exactly milled product shot on the conveying chain with a tolerance of ± 1 mm ensures a very exact positioning and repeat accuracy when approaching or leaving the loading or unloading position. In addition, a well-thought-out safety concept was implemented which covers the complete conveyor and the danger areas with cable control switches.