Patent ID: 7823412

Claim:
An oil separator including a hermetic vessel, the hermetic vessel comprising: a vessel body; an inflow pipe through which a fluid flows into the vessel body, the inflow pipe being inserted in the vessel body through a side of the vessel body and an outlet of the inflow pipe inside the vessel body being directed along an inner peripheral surface of the vessel body to swirl the fluid entering the vessel body: a discharge pipe which is inserted into the vessel body to discharge the fluid; and an oil pipe which is connected to a bottom wall of the vessel body to discharge oil separated from the fluid, wherein the discharge pipe comprises: a first discharge pipe which guides flow of the fluid in a first direction, and a second discharge pipe which is connected to the first discharge pipe to guide flow of the fluid from the first discharge pipe in a second direction which is different from the first direction, wherein the first discharge pipe is connected to the second discharge pipe in a T-shaped configuration which has a ratio of a diameter to a length in the range of about 1:2 to 1:4 such that a ratio of a length of the first pipe to a length of the second pipe and a ratio of the diameter of the first pipe to the length of the first pipe causes a wave of a higher frequency than an audible frequency.