Method and device for mounting shaft seals permitting eccentric motion
A device and method are taught for mounting an annular shaft seal between a bore and a shaft in which the shaft and bore may be subject to radial eccentricity. The device comprises an annular sealing case having a first end and a second end; a shaft sealing case having a first end and a second end; a flexible sealing linkage axially and sealingly connecting the second end of the annular sealing case to the first end of the shaft sealing case. The annular sealing case is shaped to receive a seal to seal against an interior surface of the bore, and the shaft sealing case is shaped to receive a seal to seal against an exterior surface of the shaft, and the flexible sealing linkage provides sealing between the annular sealing case and the shaft sealing case.
1. A method for sealing between a bore and a shaft in a rotating or translating application, while allowing for radial eccentricity between the shaft and bore, said method comprising the steps of:
a. providing a sealing case system comprising:
i. an annular sealing case having a first end and a second end;
ii. a shaft sealing case having a first end and a second end; and
iii. a flexible sealing linkage axially connecting the second end of the annular sealing case to the first end of the shaft sealing case;
b. receiving one or more first seals in the annular sealing case, to statically seal the annular sealing case against an interior surface of the bore;
c. receiving one or more second seals in the shaft sealing case, to dynamically seal the shaft sealing case against an exterior surface of the shaft;
d. inserting the sealing case system with the first and second seals between the bore and the shaft; and
e. sealing between the annular sealing case and the shaft sealing case by the axial connection between the annular sealing case and the shaft sealing case by the flexible sealing linkage;
f. allowing translating of the flexible sealing linkage to accommodate radial eccentricity between the shaft and the bore; and
g. maintaining the annular sealing case in a coaxial relationship with the bore and maintaining the shaft sealing case in a coaxial relationship with the shaft.
2. The method of claim 1 further comprising providing a retaining means to retain the sealing case system in the bore.
3. The method of claim 1 wherein inserting the sealing case system with the first and second seals between the bore and the shaft comprises inserting the sealing case system with the first and second seals into bore; and then inserting the shaft into the seal case system.
4. The method of claim 1 wherein inserting the sealing case system with the first and second seals between the bore and the shaft comprises inserting the sealing case system with the first and second seals onto the shaft; and then inserting the shaft and the sealing case system with the first and second seals into the bore.
5. The method of claim 1 , wherein sealing between a bore and a shaft serves to prevent transfer of any one or more of fluid and pressure from an exterior cavity beyond the bore to an interior cavity of the bore.
6. The method of claim 1 wherein allowing for rotational eccentricity between the shaft and bore comprise allowing the flexible linkage to translate by an amount of rotational eccentricity while maintaining the first seal and annular sealing case to remain coaxial with the bore, and while allowing the second seal and the shaft sealing case to remain coaxial with the shaft.