cement carrier[si′ment ‚kar·ē·ər]
a transport vehicle for bulk cement. Cement carriers include motor vehicles, railroad cars, and river and oceangoing vessels. They may be equipped with horizontal or vertical tanks, and the cement feed from the tanks may be pneumatic (most common) or by gravity.
Motor vehicles are used to transport cement over distances up to 150 km. Those used in the USSR have load capacities of 8, 13.5, and 22 tons. The carrier consists of a tank on a semitrailer. Mounted inside the tank are chutes that feed air into the cement; the chutes consist of a metal trough, a porous partition made of cotton or Lavsan, and a metal incline. An air compressor is mounted on the chassis of the tractor. The carriers are usually loaded by gravity, but vacuum loading may also be used. Unloading is accomplished by starting the air compressor; air then passes through the partition of the chute into the cement in fine jets. The aerated cement flows like a liquid through the chutes (which are inclined at an angle of 6°) to a feed nozzle. Compressed air feeds the cement through the nozzle to a tower, which may be up to 25 m high.
Equipment used to transport cement by railroad over distances up to 1,000 km includes hopper cars with a load capacity of 60 tons, tank cars with a load capacity of 58 tons, and platform cars, on which several tanks may be mounted.
Cement-carrying ships are used in cases where the cement factory is located near waterways. The load capacities of such ships may reach 5,000 tons. Transportation by ship is also used for cement loaded in containers.
REFERENCESPnevmotransportnye ustanovki: Spravochnik. Leningrad, 1969.
Matveev, A. I. Sostoianie i perspektivy razvitiia oborudovaniia dliasistem pnevmotransporta. Moscow, 1975.