Patent ID: 8608176

Claim:
Sealing arrangement for a rotating shaft through a bore penetrating a housing, said housing having an inside containing a working medium at elevated pressure, a housing projection extending coaxially around the shaft away from the inside of the housing and defining said bore, and a housing outside at ambient pressure, said bore having an inner side facing said shaft and receiving a plurality of lip seals and an outer side exposed to said ambient pressure, comprising: a pressurized fluid chamber within the bore adjacent the shaft; a gap along the shaft, providing direct fluid communication from a first portion of the chamber closer to the inside of the housing to the working medium at elevated pressure inside of the housing; one of said lip seals with a sealing lip in contact with the shaft and facing a second portion of the chamber farther from the inside of the housing; a source of pressurized fluid delivered through a passage in the housing directly into the chamber; wherein the gap throttles outflow of pressurized fluid from the first portion of the chamber to the working medium inside of the housing and thereby maintains sufficient fluid pressure in the second portion of the chamber to load the sealing lip against the shaft; at least one other pressurized fluid chamber arranged axially in series in a direction away from the inside of the housing and situated between the bore and the shaft, each of the other chambers having a first portion closer to the inside of the housing and a second portion farther from the inside of the housing, and a respective other of said lip seals arranged along the shaft, each of said other lip seals facing the second portion of a respective other pressurized chamber, and each having a respective sealing lip in contact with the shaft and facing the inside of the housing; a further lip seal farthest from the inside of the housing with an associated chamber between it and an adjacent other lip seal next closer to the inside of the housing with a respective associated pressurized chamber; and a discharge passage leading from the associated chamber of the further lip seal to said ambient pressure through which discharge passage pressurized fluid escaping from the chamber of the next closer lip seal is discharged.