| 摘要 |
A system for spraying materials on a surface around a common point involving a swivel with supply lines extending to the same and also supply lines extending from the same to a nozzle moving adjacent to such surface. The nozzle is mounted on an elevator which is movable in a tower, the tower itself being movable adjacent to such surface. The nozzle on the tower is connected to a portion of the swivel so as to move therewith so that supply lines extending from the swivel to the nozzle are not tangled or otherwise fouled during movement of the nozzle. The swivel itself may be used in guniting operations and as exemplified is constructed of generally concentric tubular elements which define a first passageway for a cement-sand mixture, a second passageway for the flow of water, and a third passageway for the flow of air for operation of a first air motor used in raising the elevator and also to a second air motor for moving the tower. The passageway for the abrasive cement-sand mixture incorporates a removable liner which normally protects a swivel bearing and seals and an air stream is directed between such liner and said bearing to maintain the same free from the otherwise abrasive effects of the cement-sand mixture and thereby prevent damages to said bearing and seals.
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