exhaust unit in addition a control valve is employed at an inlet section of an exhaust pipe one end of this exhaust pipe is opened inside a muffler which forms airtight space within a closed case this control valve is actuated by means of a slider valve body by receiving specific pressure application_number US 7792387 A description referring now to fig3 there is shown a fragmentary sectional view of a rotary compressor according to one preferred embodiment of the invention it should be noted that the same reference numerals shown in fig1 and 2 will be employed as those for denoting the same elements shown in fig3 the rotary compressor 1 as illustrated in fig3 employs the closed case 7 the closed case 7 contains the compression element 8 electrically powered drive element 9 an exhaust valve 14 disposed on a part of the compressor mechanism and a muffler 13 made of a sheet metal for covering the exhaust valve 14 the exhaust valve 14 is opened or closed by the pressure difference between the internal pressure of the muffler 13 and the pressure in the cylinder when the valve 14 is opened the exhaust gas is exhausted from the cylinder into the muffler and when the valve is closed the reverse flow of the gas in the muffler into the cylinder is blocked one end of the exhaust pipe 11 is directly connected to the refrigerant circuit outside the closed case 7 and the other end thereof is opened to this sheet metal muffler 13 via a part of thrust bearing 16 of the compression element 8 then a control valve 30 is positioned adjacent an opening 17 this control valve 30 is constructed by.