Forged valve stem packing set
AssigneeGarlock Inc.
InventorMichael J. Webb
Life of this patent
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Abstract
A three-ring packing set for a forged valve stem is disclosed which includes upper and lower adapter rings formed from fiber reinforced graphite tape and each having a first density and a first axial thickness, and an intermediate preform ring formed from graphite tape and having a second density that is less than the density of the upper and lower adapter rings and a second axial thickness that is less than the axial thickness of each of the adapter rings.
Claims30
A stuffing box packing for a valve stem, comprising:
- a) an upper adapter ring formed from reinforced graphite tape, having a first density and a first axial thickness;
- b) an intermediate preform ring formed from graphite tape, having a second density less than the density of the upper adapter ring and a second axial thickness less than the axial thickness of the upper adapter ring;
- and
- c) a lower adapter ring formed from reinforced graphite tape, having a density equal to the density of the upper adapter ring and having an axial thickness equal to the axial thickness of the upper adapter ring, wherein the upper and lower adapter rings are formed by means other than braiding and the intermediate preform ring is nested between the upper and lower adapter rings.
A stuffing box packing for a valve stem comprising:
- a) an upper adapter ring formed from reinforced graphite tape, having a first density and a first axial thickness, said upper adapter ring having a lower concave facing surface;
- b) an intermediate preform ring formed from graphite tape, having a second density less than the density of the upper adapter ring and a second axial thickness less than the axial thickness of the upper adapter ring, said intermediate preform ring having opposed upper convex and lower concave facing surfaces;
- and
- c) a lower adapter ring formed from reinforced graphite tape, having a density equal to the density of the upper adapter ring and having an axial thickness equal to the axial thickness of the upper adapter ring, said lower adapter ring having an upper convex facing surface, wherein the upper and lower adapter rings are formed by means other than braiding and the intermediate preform ring is nested between the upper and lower adapter rings.
A three-ring stuffing box packing set for a valve stem, wherein the stuffing box has a diameter “D” and the valve stem has a diameter “d” such that the stuffing box has a cross-sectional dimension “CS” expressed by (D−d)2, the packing set comprising:
- a) an upper adapter ring formed from reinforced graphite tape having a first density and a first axial thickness in the range of about approximately 0.5·CS to about approximately 3·CS;
- b) an intermediate preform ring formed from graphite tape having a second density less than the density of the upper adapter ring and a second axial thickness less than the axial thickness of the upper adapter ring in the range of about approximately 0.75·CS to about approximately 2·CS;
- and
- c) a lower adapter ring formed from reinforced graphite having a density equal to the density of the upper adapter ring and having an axial thickness equal to the axial thickness of the upper adapter ring, wherein the upper and lower adapter rings are formed by means other than braiding and the intermediate preform ring is nested between the upper and lower adapter rings.
Dependencies are inferred from the claim text.