A Prototipe for the Soil Sterilizing

A machine for the soil thermo - mechanics sterilization, has been designed and realized. It is formed from a loom provided of wheels on which are installed: a soil cutting device, a soil conveyer device and a rotating oven whose axis is tilted of 20° in comparison to the horizontal axis. The working width is 1 m. The working depth is suitable until 30 cm. The speed has been 2 m/s with working capability of 0.72 ha/h and with speed of 3 m/s the working capability has been 1.08 ha/h. The ribbon conveyer, completely closed and sealed, it performs the soil transport to the hopper of the rotating oven. The rotating oven is formed from a rotating cylinder with length of 2.500 mm, with a diameter of 500 mm and with angular speed = 3.2 1/s. A burner, situated at the extremity of the cylinder, it produces a flame along the cylinder axis. It produces a temperatures distribution inside the cylinder that has been determined by mean a thermodynamic study of the considered process. The soil carried upward by the ribbon conveyor, in around 3 s, it comes in the hopper of the rotating cylinder. It moves toward the cylinder outlet, because of the inclination and rotating motion of the cylinder, advancing in counter-current to the heat propagation. Besides the soil, because of the rotating motion of the cylinder considered, is dragged upward for then reverting in the low part of the cylinder, with further soil breaking up. This is also made easy because there is a metallic fin on the cylinder inside surface. Under such operative conditions the heat transfer in the soil is facilitated and therefore it increases the effectiveness of the soil disinfectant treatment during the range time when it crosses the whole length of the cylinder. It has been seen that with the values used of speed during the tests, it is avoided the “cooking” of the contained clay in the considered soil. On the soil samples treated in such way, physical, chemical and microbiological analysis have been performed, and satisfactory data results have been obtained from the point of view of the performed treatment. Besides a moisture loss has been noticed of about 3-4% while macroscopically burnt and pulverized zones and reduction of organic substance are not been underlined. The obtained data results show that such machine perform a good soil sterilization treatment.