Swirl control labyrinth seal
First Claim
1. An apparatus comprising a housing, a rotatable shaft positioned in said housing, a low pressure chamber in said housing for containing a fluid at a low pressure, a high pressure chamber in said housing for containing said fluid at a high pressure, said rotatable shaft constituting a rotatable element, an annular labyrinth seal element positioned coaxially with said rotatable shaft and between a rotatable element and said housing, said annular labyrinth seal element having a plurality of annular teeth facing a radially adjacent surface, said annular labyrinth seal element having a first annular end exposed to said high pressure chamber and a second annular end exposed to said low pressure chamber, said annular teeth being spaced along the longitudinal length of the annular labyrinth seal element between said first and second annular ends, said annular teeth extending radially into sealing relationship with said radially adjacent surface such that a portion of said fluid passes from said high pressure chamber at said first annular end through the annular space between said annular teeth and said radially adjacent surface to said low pressure chamber at said second annular end with the rotation of said rotatable shaft tending to cause a circumferential flow of said portion of said fluid as said portion of said fluid passes through said annular space, a first plurality of flow bypass passageways, each of said first plurality of flow bypass passageways being stationary and extending from a predetermined opening in said high pressure chamber to a respective one of a first plurality of openings located in an annular chamber formed between a predetermined adjacent pair of said annular teeth, said first plurality of openings being spaced at least substantially uniformly about the circumference of said annular chamber, wherein the flow resistance from said high pressure chamber through said first plurality of flow bypass passageways to said annular chamber is substantially less than the flow resistance through the portion of said annular space from said first annular end to said annular chamber, thereby reducing the circumferential flow of said portion of said fluid passing from said high pressure chamber through said annular space to said low pressure chamber.
1 Assignment
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Accused Products
Abstract
A labyrinth seal which reduces the inlet swirl and circumferential flow of fluid within the sealing cavity of a rotating shaft system in order to eliminate the destabilizing influence of the labyrinth seal, has a plurality of primary flow bypass passageways which extend from the high pressure face of the seal to the space between a first set and a second set of labyrinth teeth. The plurality of primary flow bypass passageways are equally spaced around the circumference of the seal and are preferably inclined such that the fluid is introduced into the seal cavity at a desired orientation. Each of the primary flow bypass passageways can be a passageway which is inclined at an acute angle to the shaft axis or a combination of an axial passageway and a radial passageway. The primary flow bypass passageways can be in the form of a plurality of generally radial passageways which intersect a common annular opening in the high pressure face of the seal. Also, multiple sets of secondary flow bypass passageways can be positioned at predetermined locations downstream from the first set of passages to function in a similar manner. Annular grooves can be provided in the outer surface of the seal to connect each adjacent set of secondary flow bypass passageways which straddle a set of labyrinth teeth.
111 Citations
53 Claims
- 1. An apparatus comprising a housing, a rotatable shaft positioned in said housing, a low pressure chamber in said housing for containing a fluid at a low pressure, a high pressure chamber in said housing for containing said fluid at a high pressure, said rotatable shaft constituting a rotatable element, an annular labyrinth seal element positioned coaxially with said rotatable shaft and between a rotatable element and said housing, said annular labyrinth seal element having a plurality of annular teeth facing a radially adjacent surface, said annular labyrinth seal element having a first annular end exposed to said high pressure chamber and a second annular end exposed to said low pressure chamber, said annular teeth being spaced along the longitudinal length of the annular labyrinth seal element between said first and second annular ends, said annular teeth extending radially into sealing relationship with said radially adjacent surface such that a portion of said fluid passes from said high pressure chamber at said first annular end through the annular space between said annular teeth and said radially adjacent surface to said low pressure chamber at said second annular end with the rotation of said rotatable shaft tending to cause a circumferential flow of said portion of said fluid as said portion of said fluid passes through said annular space, a first plurality of flow bypass passageways, each of said first plurality of flow bypass passageways being stationary and extending from a predetermined opening in said high pressure chamber to a respective one of a first plurality of openings located in an annular chamber formed between a predetermined adjacent pair of said annular teeth, said first plurality of openings being spaced at least substantially uniformly about the circumference of said annular chamber, wherein the flow resistance from said high pressure chamber through said first plurality of flow bypass passageways to said annular chamber is substantially less than the flow resistance through the portion of said annular space from said first annular end to said annular chamber, thereby reducing the circumferential flow of said portion of said fluid passing from said high pressure chamber through said annular space to said low pressure chamber.
- 8. An apparatus comprising a housing, a rotatable shaft positioned in said housing, a low pressure chamber in said housing for containing a fluid at a low pressure, a high pressure chamber in said housing for containing said fluid at a high pressure, said rotatable shaft constituting a rotatable element, an annular labyrinth seal element positioned coaxially with said rotatable shaft and between a rotatable element and said housing, said annular labyrinth seal element having a plurality of annular teeth facing a radially adjacent surface, said annular labyrinth seal element having a first annular end exposed to said high pressure chamber and a second annular end exposed to said low pressure chamber, said annular teeth being spaced along the longitudinal length of said annular labyrinth seal element between said first and second annular ends, said annular teeth extending radially into sealing relationship with said radially adjacent surface such that a portion of said fluid passes from said high pressure chamber at said first annular end through the annular space between said annular teeth and said radially adjacent surface to said low pressure chamber at said second annular end with the rotation of said rotatable shaft tending to cause a circumferential flow of said portion of said fluid as said portion of said fluid passes through said annular space, a first plurality of flow bypass passageways being stationary and extending from a predetermined opening in said high pressure chamber to a respective one of a first plurality of openings located in an annular chamber formed between a predetermined adjacent pair of said annular teeth, said first plurality of openings being spaced at least substantially uniformly about the circumference of said annular chamber, wherein the flow resistance from said high pressure chamber through said first plurality of flow bypass passageways to said annular chamber is substantially less than the flow resistance through the portion of said annular space from said first annular end to said annular chamber, thereby reducing the circumferential flow of said portion of said fluid passing from said high pressure chamber through said annular space to said low pressure chamber, wherein said predetermined opening in said high pressure chamber comprises a second plurality of openings in said first annular end which are spaced at least substantially uniformly in a circular array, corresponding in number to said first plurality of flow bypass passageways, each of said first plurality of flow bypass passageways having a first portion extending at least generally parallel to the longitudinal axis of said rotatable shaft to intersect a respective one of said second plurality of openings and having a second portion extending from a respective one of said first plurality of openings in said annular chamber at least generally outwardly with respect to said rotatable shaft to intersect the associated first portion, wherein said second portion of each of said first plurality of flow bypass passageways is inclined with respect to a reference line at an angle of inclination such that fluid enters said annular chamber from the respective one of said first plurality of flow bypass passageways in a direction opposite to the rotation of said rotatable shaft, said reference line being radial to said rotatable shaft.
- 21. An apparatus comprising a housing, a rotatable shaft positioned in said housing, a low pressure chamber in said housing for containing a fluid at a low pressure, a high pressure chamber in said housing for containing said fluid at a high pressure, said rotatable shaft constituting a rotatable element, an annular labyrinth seal element positioned coaxially with said rotatable shaft and between a rotatable element and said housing, said annular labyrinth seal element having a plurality of annular teeth facing a radially adjacent surface, said annular labyrinth seal element having a first annular end exposed to said high pressure chamber and a second annular end exposed to said low pressure chamber, said annular teeth being spaced along the longitudinal length of said annular labyrinth seal element between said first and second annular ends, said annular teeth extending radially into sealing relationship with said radially adjacent surface such that a portion of said fluid passes from said high pressure chamber at said first annular end through the annular space between said annular teeth and said radially adjacent surface to said low pressure chamber at said second annular end with the rotation of said rotatable shaft tending to cause a circumferential flow of said portion of said fluid as said portion of said fluid passes through said annular space, a first plurality of flow bypass passageways, each of said first plurality of flow bypass passageways being stationary and extending from a predetermined opening in said high pressure chamber to a respective one of a first plurality of openings located in an annular chamber formed between a predetermined adjacent pair of said annular teeth, said first plurality of openings being spaced at least substantially uniformly about the circumference of said annular chamber, wherein the flow resistance from said high pressure chamber through said first plurality of flow bypass passageways to said annular chamber is substantially less than the flow resistance through the portion of said annular space from said first annular end to said annular chamber, thereby reducing the circumferential flow of said portion of said fluid passing from said high pressure chamber through said annular space to said low pressure chamber, wherein said predetermined opening in said high pressure chamber comprises an annular slot formed in said first annular end and extending at least substantially coaxially with respect to said rotatable shaft, and wherein each of said first plurality of flow bypass passageways extends at least generally outwardly from said annular chamber with respect to said rotatable shaft to intersect said annular slot, wherein each of said first plurality of flow bypass passageways is inclined with respect to a reference line at an angle of inclination such that fluid enters said annular chamber from the respective one of said first plurality of flow bypass passageways in a direction opposite to the rotation of said rotatable shaft, said reference line being radial to said rotatable shaft.
- 34. An apparatus comprising a housing, a rotatable shaft positioned in said housing, a low pressure chamber in said housing for containing a fluid at a low pressure, a high pressure chamber in said housing for containing said fluid at a high pressure, said rotatable shaft constituting a rotatable element, an annular labyrinth seal element positioned coaxially with said rotatable shaft and between a rotatable element and said housing, said annular labyrinth seal element having a plurality of annular teeth facing a radially adjacent surface, said annular labyrinth seal element having a first annular end exposed to said high pressure chamber and a second annular end exposed to said low pressure chamber, said annular teeth being spaced along the longitudinal length of said annular labyrinth seal element between said first and second annular ends, said annular teeth extending radially into sealing relationship with said radially adjacent surface such that a portion of said fluid passes from said high pressure chamber at said first annular end through the annular space between said annular teeth and said radially adjacent surface to said low pressure chamber at said second annular end with the rotation of said rotatable shaft tending to cause a circumferential flow of said portion of said fluid as said portion of said fluid passes through said annular space, a first plurality of flow bypass passageways, each of said first plurality of flow bypass passageways being stationary and extending from a predetermined opening in said high pressure chamber to a respective one of a first plurality of openings located in an annular chamber formed between a predetermined adjacent pair of said annular teeth, said first plurality of openings being spaced at least substantially uniformly about the circumference of said annular chamber, wherein the flow resistance from said high pressure chamber through said first plurality of flow bypass passageways to said annular chamber is substantially less than the flow resistance through the portion of said annular space from said first annular end to said annular chamber, thereby reducing the circumferential flow of said portion of said fluid passing from said high pressure chamber through said annular space to said low pressure chamber, wherein said predetermined opening in said high pressure chamber comprises an annular groove formed in said first annular end around the circumference of the labyrinth seal element and extending at least substantially coaxially with respect to said rotatable element and wherein each of said flow bypass passageways extends at least generally outwardly from said annular chamber with respect to said rotatable shaft to intersect said annular groove, wherein each of said first plurality of flow bypass passageways is inclined with respect to a reference line at an angle of inclination such that fluid enters said annular chamber from the respective one of said first plurality of flow bypass passageways in a direction opposite to the rotation of said rotatable shaft, said reference line being radial to said rotatable shaft.
- 49. An apparatus comprising a housing, a rotatable shaft positioned in said housing, a low pressure chamber in said housing for containing a fluid at a low pressure, a high pressure chamber in said housing for containing said fluid at a high pressure, said rotatable shaft constituting a rotatable element, an annular labyrinth seal element positioned coaxially with said rotatable shaft and between a rotatable element and said housing, said annular labyrinth seal element having a plurality of annular teeth facing a radially adjacent surface, said annular labyrinth seal element having a first annular end exposed to said high pressure chamber and a second annular end exposed to said low pressure chamber, said annular teeth being spaced along the longitudinal length of said annular labyrinth seal element between said first and second annular ends, said annular teeth extending radially into sealing relationship with said radially adjacent surface such that a portion of said fluid passes from said high pressure chamber at said first annular end through the annular space between said annular teeth and said radially adjacent surface to said low pressure chamber at said second annular end with the rotation of said rotatable shaft tending to cause a circumferential flow of said portion of said fluid as said portion of said fluid passes through said annular space, a first plurality of flow bypass passageways, being stationary and extending from a predetermined opening in said high pressure chamber to a respective one of a first plurality of openings located in an annular chamber formed between a predetermined adjacent pair of said annular teeth, said first plurality of openings being spaced at least substantially uniformly about the circumference of said annular chamber, wherein the flow resistance from said high pressure chamber through said first plurality of flow bypass passageways to said annular chamber is substantially less than the flow resistance through the portion of said annular space from said first annular end to said annular chamber, thereby reducing the circumferential flow of said portion of said fluid passing from said high pressure chamber through said annular space to said low pressure chamber, wherein each of said first plurality of flow bypass passageways is at least substantially a cylindrical bore extending from said first annular end to said annular chamber at an acute angle to the longitudinal axis of said rotatable element, wherein each of said first plurality of flow bypass passageways is inclined with respect to a reference line at an angle of inclination such that fluid enters said annular chamber from the respective one of said first plurality of flow bypass passageways in a direction opposite to the rotation of said rotatable shaft, said reference line being radial to said rotatable shaft.
Specification