RECIPROCATING PISTON COMPRESSOR HAVING IMPROVED NOISE ATTENUATION
A reciprocating piston compressor having a suction muffler and a pair of discharge mufflers to attenuate noise created by the primary pumping frequency in the primary pumping pulse. The suction muffler is disposed along a suction tube extending between the motor cap and the cylinder head of the compressor. The discharge mufflers are positioned in series within the compressor to receive discharge gases from the compression mechanism and are spaced one quarter of a wavelength from each other so as to sequentially diminish the problematic or noisy frequencies created during compressor operation. The motor/compressor assembly including the motor and compression mechanism is mounted to the interior surface of the compressor housing by spring mounts. These mounted are secured to the housing to define the position of the nodes and anti-nodes of the frequency created in the housing to reduce noise produced by natural frequencies during compressor operation.
1 - 25 . (canceled)
26 . A compressor assembly comprising:
a housing having at least one natural frequency having a wave form with amplitude large enough for said housing, when vibrated at that frequency, to produce an objectionable noise, said natural frequency wave form having a plurality of natural nodes equally distributed about the circumference of said housing and natural anti-nodes located between adjacent natural nodes;
a motor/compressor assembly comprising a compression mechanism in which gas is compressed from substantially a suction pressure to substantially a discharge pressure, and a motor operably engaged with said compressor mechanism; and
a plurality of mounts unequally distributed about the circumference of said housing, said motor/compressor assembly being supported within said housing by said mounts;
wherein each said mount is attached to said housing at a first point, said first points not coinciding with the natural nodes of said natural frequency wave form and defining forced nodes on the circumference of said housing to which the nodes of said natural frequency wave form are forced, said natural frequency wave form being altered in response to the natural nodes being forced to the forced nodes, whereby said housing is prevented from vibrating at said natural frequency.
27 . The compressor assembly of claim 26 , wherein each said mount is attached to said housing at a second point, said second points defining positions about the circumference of said housing at which forced anti-nodes of said altered wave form are located.
28 . The compressor assembly of claim 26 , wherein said motor/compressor assembly is resiliently supported within said housing.