| 摘要 |
The invention provides a novel impact angle changing shower for spraying a fluid upon a moving belt surface while the belt travels at a selected belt velocity. The shower includes nozzles journaled to rotation about an axis in a plane normal to the belt surface and transverse to the belt direction. The nozzles are continuously supplied with pressurized fluid and direct a fluid stream at a selected nozzle velocity and nozzle angle relative to the plane. The orientation of the nozzles is selected to optimize the desired function namely, to clean the belt surface without damaging the belt fabric or felt, or to penetrate the belt to increase fluid absorption by the belt. The fluid stream nozzle velocity can be decomposed using vector mathematics into two vector components: a belt velocity vector component parallel to the belt direction; and a belt impact velocity vector oriented at an impact angle defined relative to the normal transverse plane. By recognizing the effect of belt velocity on the performance of the nozzles, the optimum nozzle velocity and orientation can be determined for the desired function. Prior art selection of nozzle velocity and orientation relies on experience or trial and error rather than scientific analysis. Rotary actuators are used to rotate the nozzles about the transverse axis between: a belt penetration position where the impact angle equals zero and the belt velocity vector component of the nozzle velocity is equal to the belt velocity; and a belt surface chiselling position where the impact angle is greater than zero and less than 90 degrees, and preferably in the range between 10 to 45 degrees. The rotary actuator can be controlled with a timer to rotate the nozzles in a predetermined timed sequence. To oscillate the nozzles transversely across the belt for uniform coverage over the entire belt surface, either a separate transverse actuator can be provided or a single actuator that rotates and oscillates the nozzle mounting pipe can be included.
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