Patent ID: 8523015

Claim:
A reciprocating motor pump suitable to generate compressed gas with a reduced noise level, said pump includes a pump casing comprising: a wall; a gas chamber formed above the wall; a cylinder chamber formed below the wall and comprising a piston, an inner volume of the gas chamber being larger than a maximum stroke volume of the cylinder chamber; an inlet valve and an outlet valve formed in the wall; a gas inlet nozzle positioned in the gas chamber; and a gas outlet port positioned in the gas chamber and coupled to the outlet valve, gas enters the gas chamber through the gas inlet nozzle and then flows from said gas chamber to said cylinder chamber through the inlet valve, the ratio of a diameter of an opening of a gas passage of said inlet nozzle to a diameter of an opening of gas passage of said inlet valve is in the range of 1:15 to 1:5 and the noise level generated by the motor pump is at most 55 dB.