Patent ID: 7588426

Claim:
A method of manufacturing an oil rotary vacuum pump of mechanical type ( 100 ), comprising the steps of: providing external ( 1 ) and internal ( 2 ) casings with a suction duct ( 5 ) including a suction port ( 3 ) and an exhaust duct ( 15 ) including and an exhaust port ( 17 ); positioning a rotor ( 9 ) within a chamber ( 7 ) forming within the internal casing; providing an opening ( 12 ) within the external casing; creating an oil bath ( 19 ) by poring through the opening ( 12 ) a requested amount of oil to immerse the internal casing therein; closing the opening ( 12 ); applying a sealing member ( 21 , 23 ) to the suction port ( 3 ) and/or the exhaust port ( 17 ), wherein said sealing member ( 21 , 23 ) comprises a membrane ( 21 , 23 ) formed of a thin film subject to tearing without producing fragments thereof on application of a pressure difference across the film, whereby said oil bath is not diminished from leakage out of said suction port ( 3 ) and/or exhaust port ( 17 ) during shipment or storage; and removing said sealing member ( 21 , 23 ) before starting said pump for the first time.