Fluidborne noise attenuator
AssigneeCaterpillar Tractor Co.
InventorRobert C. Hansen
Life of this patent
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Abstract
A fluidborne noise attenuator (14) comprises a dampening medium (27) which exhibits a bulk modulus (e.g., 50,000 psi to 180,000 psi) substantially greater than that of an inert gas, such as nitrogen, and substantially less than that of a hydraulic working fluid (e.g., 225,000 psi). The attenuator (14) is capable of attenuating noise levels of hydraulic fluid over wide frequency and mean system pressure ranges in contrast to conventional attenuators which are "tuned" for the attenuation of noise levels at a specific frequency and mean system pressure.
Claims15
A hydraulic fluidborne noise attenuator (14) comprising
- a rigid, tubular outer casing (22),
- flow passage means (14') for communicating hydraulic fluid through said attenuator (14), said flow passage means (14') having an inlet (13) at a first end thereof and an outlet (15) at a second end thereof, and
- fluidborne noise means (27) for exhibiting a bulk modulus substantially greater than the bulk modulus of a gas and substantially less then the bulk modulus of said hydraulic fluid to attenuate noise levels at frequencies that vary over at least substantially the entire frequency range of from 100 to 5,000 Hz generated by flow and pressure fluctuations of said hydraulic fluid by tuning said fluidborne noise attenuator (14) to various portions of said entire frequency range, said fluidborne noise means (27) being at least generally tubular in shape and tapered downwardly at least approximately uniformly from said first end towards said second end of said attenuator with the diametrical size of said fluidborne noise means (27) being larger at said first end than at said second end.
A hydraulic fluidborne noise attenuator (14) comprising
- a rigid, tubular outer casing (22),
- flow passage means (14') for communicating hydraulic fluid through said attenuator (14), said flow passage means (14') having an inlet (13) at a first end thereof and an outlet (15) at a second end thereof, and
- fluidborne noise means (27) for exhibiting a bulk modulus substantially greater than the bulk modulus of a gas and substantially less than the bulk modulus of said hydraulic fluid to attenuate noise levels at frequencies that vary over at least substantially the entire frequency range of from 100 to 5,000 Hz generated by flow and pressure fluctuations of said hydraulic fluid, said fluidborne noise means (27) being at least generally tubular in shape and tapered downwardly at least approximately uniformly from said first end towards said second end of said attenuator with the diametrical size of said fluidborne noise means (27) being larger at said first end than at said second end, said fluidborne noise means (27) including a plurality of tuned compartment means for tuning said fluidborne noise attenuator (14) to various portions of said entire frequency range.
Dependencies are inferred from the claim text.