spiral chute[′spī·rəl ′shüt]
a transport mechanism for discharging bulk and piece-type goods under the force of gravity. It consists of a spiral trough mounted on a column or inside a large-diameter vertical tube; the load slides along the trough. Spiral chutes are usually 20-50 m in height, although some are 100 m or more. When moving bulk goods, their capacity ranges from 300 to 500 tons per hour with a tube of 1.2-1.5 m outside diameter. To reduce wear, the trough is made of durable materials; it also may be covered with fused basalt. Because of their simplicity and reliability, as well as the possibility of accumulating a considerable amount of material in the lower part of the trough (which is of particular importance for mining enterprises, where a spiral chute serves as an intermediate storage area at the junction of two transportation links), spiral chutes have become common in the warehouse and interoperation transportation of industrial enterprises, as well as in the mining industry.
A. A. PARKHOMENKO