Pump jet rotor housing modification for noise signature spectral control
AssigneeBombardier Motor Corporation of America
InventorsA. Michael Varney, John D. Martino
Life of this patent
Estimating the term…
Abstract
A pump jet having a perforated wear liner inside the rotor housing for altering the spectrum of noise produced by the pump jet. The perforated wear liner is inserted in a circumferential recess formed on the inner surface of the rotor housing and surrounds the rotor tip region. The throughholes or perforations are preferably constant in size and regularly spaced. The perforated wear liner acts as a Helmholtz resonator liner which alters the spectrum of noise emitted from the pump jet during operation. Proper selection of the size, number and spacing of the holes permits the designer to control the specific noise spectrum range that is emitted from the front and rear lobes of the pump jet, thereby altering the hydrodynamic noise field.
Claims18
A pump jet apparatus for a marine engine, comprising:
- a rotor assembly mounted on a rotatable shaft, said rotor assembly comprising a rotor hub coupled to said rotatable shaft and a plurality of rotor blades, each rotor blade being connected at one end to said rotor hub;
- a rotor housing surrounding said rotor assembly, having an inlet and an outlet, and comprising a circumferential recess surrounding said rotor blades;
- a ring-shaped wear liner installed in said circumferential recess and having a multiplicity of holes extending radially therethrough;
- a stator housing coupled to said rotor housing and having an inlet and an outlet for water flow, said inlet of said stator housing being in flow communication with said outlet of said rotor housing;
- and
- a stator hub positioned rearwardly of said rotor hub and inside said stator housing.
A pump jet apparatus for a marine engine, comprising:
- a rotor assembly mounted on a rotatable shaft, said rotor assembly comprising a rotor hub coupled to said rotatable shaft and a plurality of rotor blades, each rotor blade being connected at one end to said rotor hub;
- a rotor housing surrounding said rotor assembly, having an inlet and an outlet;
- a ring installed between said rotor assembly and said rotor housing, said ring comprising means for altering a hydrodynamic noise field of said pump jet apparatus;
- a stator housing coupled to said rotor housing and having an inlet and an outlet for water flow, said inlet of said stator housing being in flow communication with said outlet of said rotor housing;
- and
- a stator hub positioned rearwardly of said rotor hub and inside said stator housing.
A pump jet apparatus for a marine engine, comprising:
- a rotor assembly mounted on a rotatable shaft, said rotor assembly comprising a rotor hub coupled to said rotatable shaft and a plurality of rotor blades, each rotor blade being connected at one end to said rotor hub;
- and
- a housing surrounding said rotor assembly, having an inlet and an outlet for water flow, and comprising means for altering a hydrodynamic noise field of said pump jet apparatus, said hydrodynamic noise field altering means being arranged in surrounding relationship to said rotor assembly and comprising a multiplicity of recesses, each recess comprising a respective opening in an inner circumferential surface of said housing and not penetrating through to an outer circumferential surface of said housing.
A method for retrofitting a pump jet apparatus, comprising the steps of:
- uncoupling a stator housing from a rotor housing;
- removing an unperforated wear liner from a recess in said rotor housing;
- inserting a perforated wear liner in said recess in said rotor housing;
- and
- coupling said stator housing to said rotor housing.
A method for retrofitting a pump jet apparatus, comprising the steps of:
- uncoupling a stator housing from a rotor housing;
- removing an unperforated wear liner from a recess in said rotor housing;
- forming a multiplicity of perforations in said wear liner after said removing step;
- inserting said perforated wear liner in said recess in said rotor housing;
- and
- coupling said stator housing to said rotor housing.
An apparatus for propelling a watercraft, comprising:
- a rotatable shaft;
- a powerhead coupled to said shaft for driving rotation of said shaft;
- a rotor assembly mounted on said shaft, said rotor assembly comprising a rotor hub coupled to said rotatable shaft and a plurality of rotor blades, each rotor blade being connected at one end to said rotor hub;
- and
- a housing surrounding said rotor assembly, having an inlet and an outlet for water flow, and comprising means for altering a hydrodynamic noise field of said pump jet apparatus during rotation of said shaft, said hydrodynamic noise field altering means being arranged in surrounding relationship to said rotor assembly and comprising a multiplicity of recesses, each recess comprising a respective opening in an inner circumferential surface of said housing and not penetrating through to an outer circumferential surface of said housing.
Dependencies are inferred from the claim text.