Abstract: A curved area is a jet surface for jetting the air from air jet openings formed in a zigzag state. Two rollers are disposed in parallel with a turn bar so as to be adjacent to both ends of the jet surface in a transporting direction of a web. The roller rotates, contacting with a surface opposite to a levitation surface of the web, when the web is transported. Oscillation of the web is prevented and the web is prevented from coming into contact with the turn bar. Further, the air jetted from the jet surface is prevented from leaking in the transporting direction. The air leaks in a width direction of the web. An air pressure is prevented from lowering at both ends of the jet surface so that a levitation amount of the web becomes uniform.

Abstract: A fluid-pulsation preventing method and apparatus are disclosed. A fluid is pressure-fed by means of a pump along a path, a flexible pipe is provided in the path, and the volume of the flexible pipe is externally elastically controlled. This external control is such that the sectional area of the flexible pipe is controlled in accordance with pulsation by increasing or decreasing the area depending upon variations in the amount of pulsation, to thereby absorb and prevent the pulsation. This control is achieved using coil springs and rigid plates disposed so that motion of the coil springs deforms the flexible pipe through the rigid plates. The force to be applied to each of the coil springs is set to 5 to 120 Kgf or the spring constant is 0.5 to 3.0 Kgf/mm.