Supercharger rotor shaft seal pressure equalization

A pressure equalization system reduces or eliminates a pressure differential across supercharger rotor shaft seals. Under high boost, rotor shaft seals often fail, allowing hot compressed air into an oil lubricated space containing rotor bearings and gears (and vented to ambient pressure), reducing oil lubricating effectiveness and resulting in increased wear and failure. Under low or non boost operation, the pressure differential is reversed causing the lubricating oil to leak into the supercharger interior and accelerated rotor seal wear. The pressure equalization system includes flow restrictive seals on both rotor shafts, separated from the rotor shaft seals by vented spaces, thereby isolating the rotor shaft seals from boost or vacuum in the supercharger interior and reducing or eliminating the pressure differential across the rotor shaft seals. Maintaining close to atmospheric pressure on both sides of the rotor shaft seals during boost and vacuum operation reduces wear and failures.