An investigation of the factors affecting the design of drum dryers

This work is concerned with the investigation of the factors affecting the design of drum dryers. In the experimental procedure, AISI 4140 was used as a drum material, while HSS was used for a scraping knife. In order to increase the hardness and wear resistance, the drum was coated with the harder chromium, and then it was ground for the improvement of the surface quality. The micro-hardness of the drum was increased more than 10 times of the original drum; as a result better wear resistance was obtained. In addition, electrical measurements were done via a digital ohmmeter to calculate the real contact area between the drum and the scraping knife and the resistance was decreased with the increment of load. Finally, the contact between the couple (drum and knife) was increased with the increment of temperature.