Turbine seal with sealing strip and rubbing strip
AssigneeInnovative Technology Limited
InventorsWilliam P. Sanders, Anthony F. Mitola
Life of this patent
Estimating the term…
Abstract
A rubbing strip is used in conjunction with the sealing strips of a seal to prevent contact between the sealing strips and a rotating member with which the sealing strips form a seal. The rubbing strip comprises a strip of material which is oriented coaxially with the sealing strips and which has a clearance with respect to the rotating member which is less than the least of the clearances provided by the sealing strips with which it is associated. The material and the cross-sectional shape of the rubbing strip may be selected in accordance with desired wear properties. The rubbing strip may be formed integrally with a sealing ring, or may be formed to be inserted into a complementary receiving recess on a sealing ring.
Claims34
A seal for a turbine comprising:
- ring means, supportable by a stationary member of said turbine, for encircling a rotating member of said turbine,
- at least one substantially circular sealing strip supported by said ring means and extending from said ring means toward an exterior surface of said rotating member, and
- a substantially circular rubbing strip supported by said ring means and extending from said ring means toward said exterior surface of said rotating member,
- said rubbing strip having a clearance with respect to said exterior surface of said rotating member which is less than the least of clearances of said at least one sealing strip with respect to said exterior surface of said rotating member,
- said rubbing strip being axially separated from each of said at least one sealing strips.
A shaft end packing for a providing a seal about a rotor of a turbine, comprising:
- packing head means for encircling said rotor and including receiving means for receiving one or more ring segments, and
- a plurality of ring segments mounted to said packing head means, said ring segments each comprising:
- at least one sealing strip segment extending radially inward toward an exterior surface of said rotor, and
- a rubbing strip segment extending radially inward toward said exterior surface of said rotor,
- said rubbing strip segment having a radial clearance with respect to said exterior surface which is less than the least of radial clearances of said at least one sealing strip segment with respect to said exterior surface,
- said rubbing strip segment being axially separated from each of said at least one sealing strip segments.
A ring segment for a shaft end packing for providing a seal about a rotating member of a turbine, said rotating member having an external surface, said packing ring segment comprising:
- a base portion,
- N sealing strip segments, where (N.gtoreq.1), said sealing strip segments being coextensive with said base portion and extending radially inward from said base portion, each sealing strip segment having an interior radius R.sub.Nseal, and each sealing strip segment corresponding to one of N portions of said rotating member, each of said portions of said rotating member having an external radius R.sub.Nrotor, and
- a rubbing strip segment coextensive with said base portion and extending radially inward from said base portion, and having an internal radius R.sub.RUB, said rubbing strip segment corresponding to a portion of said rotor having an external radius R.sub.ROTOR,
- said rubbing strip segment having a radial clearance (R.sub.RUB -R.sub.ROTOR) which is less than the least of radial clearances (R.sub.Nseal -R.sub.Nrotor) of said N sealing strip segments,
- said rubbing strip segment being axially separated from each of said N sealing strip segments.
A rubbing strip segment for use in a ring segment of a steam seal formed about a rotating member of a turbine in an axially separated orientation from all sealing strip segments of said ring segment, said ring segment including N sealing strip segments, where (N.gtoreq.1), said sealing strip segments being coextensive with said ring segment and extending radially inward from said ring segment, each of said sealing strip segments having an interior radius R.sub.Nseal, and each of said sealing strip segments corresponding to one of N portions of said rotating member, each of said portions of said rotating member having an external radius R.sub.Nrotor, said rubbing strip segment comprising:
- an arcuate member having a root portion and a rubbing portion integral with said root portion,
- said rubbing portion having an internal radius R.sub.RUB,
- said rubbing portion corresponding to a portion of said rotating member, said portion of said rotating member having an external radius R.sub.ROTOR,
- said rubbing strip segment providing a radial clearance (R.sub.RUB -R.sub.ROTOR) which is less than the least of respective radial clearances (R.sub.Nseal -R.sub.Nrotor) provided by said N sealing strips.
Dependencies are inferred from the claim text.