Patent ID: 7866955

Claim:
A suction muffler for a reciprocating hermetic compressor mounted inside a hermetic shell, said suction muffler comprising: a hollow body defining at least one acoustic chamber, said at least one acoustic chamber having a lower wall provided with a restricting orifice for draining oil; the hollow body being provided with a gas inlet connected to a suction line by means of a tubular connector and a gas outlet connected to a suction valve of the compressor; the hollow body further comprising an equalizing chamber having an opening to the interior of the hermetic shell on one side, and a fluid communication with the acoustic chamber on the other side; wherein said equalizing chamber has an elongated shape and an internal volume with a cross section that is substantially uniform along the extension of said internal volume, the fluid communication being defined by a second orifice provided adjacent to the gas outlet of the hollow body, said second orifice being disposed in a wall different from the lower wall of the hollow body and common to only the acoustic chamber and the equalizing chamber; wherein the equalizing chamber and said second orifice are dimensioned to prevent gas contained inside the hermetic shell from entering the acoustic chamber, said equalizing chamber having only one portion of its internal volume, defined adjacent to the second orifice, alternatively filled with the gas coming from the acoustic chamber and with the gas coming from the remaining internal volume of the equalizing chamber upon normal operation of the compressor; wherein said equalizing chamber opening being dimensioned to allow said remaining internal volume of the equalizing chamber to be filled with gas from the inside of the hermetic shell; and wherein the equalizing chamber and said second orifice are also dimensioned to minimize the noises from the gas pulses inside the suction muffler, the mixture of said gas with the gas contained within the hermetic shell, and the pressure differential between the exterior of the hermetic shell and the suction line, upon operation of the compressor after a stop period.