Title:
CHANGE OF PUMP JET ROTOR HOUSING FOR PERFORMING SPECTRAL CONTROL OF NOISE SIGNAL
Document Type and Number:
Japanese Patent JP2001138990
Kind Code:
A
Abstract:
To change the spectrum of noise generated from a pump jet.
A wear-resistant perforated liner 66' is inserted in a peripheral recess formed on the inner surface of a rotor housing 32, to surround the tip area of a rotor. Through holes or holes 68 are preferably constant in size and regularly spaced. The wear-resistant perforated liner 66' acts as a Helmholtz resonator liner for changing the spectrum of noise emitted from a pump jet during operation. The size, number and spacing of the holes are appropriately selected to control a specific spectrum range of noise emitted from the front and rear lobes of the pump jet, to thereby change a hydrodynamic noise field.
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Inventors:
VARNEY A MICHAEL
MARTINO JOHN D
MARTINO JOHN D
Application Number:
JP2000271390A
Publication Date:
May 22, 2001
Filing Date:
September 07, 2000
Export Citation:
Assignee:
OUTBOARD MARINE CORP
International Classes:
B63B35/73; B63H11/08; (IPC1-7): B63H11/08; B63B35/73
Attorney, Agent or Firm:
Kazuo Shamoto (5 outside)