Keiichi Katayama

Wire-Screen Belt Vibrations in a Fourdrinier Paper Machine.

In a Fourdrinier paper machine, the fiber and water mixture flows to a wire-screen belt. As the wire-screen belt travels horizontally, water is drained through the screen, leaving the fibers on top. In some operating conditions large vertical vibrations of the wire-screen belt occur. The mechanism of this phenomenon is investigated experimentally. Analytical study is also done, which shows qualitative agreement with the experiment results. Consequently, the screen vibration is self-excited vibration due to the pressure variation of the water on the wire screen belt.

Flow Induced Vibrations in Engineering Systems and the Control of Flow Induced Vibrations. Water-Flow Experiment on Acoustic Exciting Force of Tube Bundle in Cross Flow.

Tube bundles in cross flows sometimes excite the acoustic vibration of sound fields in heat exchanger ducts. It is considered that the acoustic vibration has a feedback circuit such as self-excited or self-controlled vibration, because there is synchronization of vortex sheddings from tubes with acoustic vibration. In this case, the fluid force can cause an acoustic vibration with large amplitude when it is in phase with the acoustically oscillating fluid velocity. The authors measured the exciting forces due to a triangularly arranged tube bundle with pitch-to-diameter ratio of 2.O in a water model duct with a transverse forced oscillating flow generator, and the characteristics of oscillating lift during acoustic vibration, such as the phase difference between oscillating lift and acoustic vibration, were clarified.

Polygonal Deformation of Roll-Covering Rubber. Practicability of Prediction Method.

Rubber-covered rolls are in wide use in many machines for processing, pressing and conveying paper and plastic film. We have studied the polygonal deformation caused by viscoelastic deformation of roll-covering rubber under high load and at high speeds. It is said that the above-mentioned phenomenon is influenced by rubber damping and its deformation recovery characteristics. Previously, we reported a prediction method for analysis of this phenomenon, regarding viscoelastic deformation as causing instability due to the time-delay deformation. In this study, we compared experimental with calculated results, and found good agreement between them. Moreover, in this report we describe methods for preventing polygonal deformation.