| 摘要 |
<p>The installation consists of a drum supported on bearing rollers driven at one end by means of a motor and chain-wheel drive. The axis of the drum is inclined to the horizontal at a narrow angle. At the lower end of the drum is an inlet opening which allows the mould blocks to be fed into the drum. Because of the inclination of the drum, the mould blocks fall into a bed of sand and castings which prevent any impact damage occuring. There are longitudinal ribs mounted on the walls of the drum, whose function is to raise the material in the drum and then let it fall, the movement separating the sand from the casting and permitting the sand to dry out. At the lower end the ribs are larger than those at the higher end. At the latter end, it is primarily the castings which are raised and allowed to fall back into the bed of sand. An exhaust fan draws off the steam and vapours from the drum via a suction hood. Spiral ribs forming an angle with the circumference of the drum tends to move the sand and castings back to the lower end of the drum. The material moving toward the upper end of the drum under the influence of the incoming material passes through a zone which is perforated to allow the sand to fall onto a collecting belt and the castings fall through the open mouth of the drum onto a belt. At the end of a work period, the rotational direction is reversed so that the sprial rib causes the sand and castings to be moved towards the mouth of the drum for emptying.</p> |
