Windback device
The present invention relates to a windback device and method of use to prevent lubricant from leaking from a lubricant sump. More specifically, the present invention is comprised of a windback device within a lubricant sump formed from the coupling of an annular sump housing, an annular fluid seal assembly, and a bearing. The annular housing substantially surrounds the runner to form a chamber. The seal assembly is coupled to a sump housing both of which are adapted to receive a rotatable runner such that a sealed chamber is formed around the runner. A plurality of inclined threads extend along an inner face of the windback device and are angled such that lubricant or fluid splashed from the rotating shaft is redirected away from a shaft seal element of the annular fluid seal and through leak off slots leading to the sump housing chamber.
1. A windback device comprising:
an annular collar having an opening therethrough wherein said opening is sized to receive a rotatable runner without contact; and
a plurality of ridges defining a plurality of inclined threads oriented circumferentially, each said inclined thread separately extending from an inner face of said annular collar toward said rotatable runner and oriented along said inner face at an oblique pitch angle with respect to a rotational axis of said rotatable runner, any two adjacent said inclined threads partially overlapping along a portion of a circumference of said annular collar, each said inclined thread having a leak-off slot at one end of said annular collar, each said inclined thread separated from said rotatable runner via a radial clearance, each said inclined thread separately assists a lubricant away from a seal, wherein a depth along each said ridge varies so as to create a positive incline angle or a negative incline angle from one end of each said inclined thread to another end thereof and between adjacent said inclined threads.
2. The windback device of claim 1 , wherein said ridges are sized and spaced equally along said inner face such that said inclined threads are of an equal width, taper angle and pitch angle.
3. The windback device of claim 1 , wherein said ridges are sized and spaced equally along said inner face such that each said inclined thread is bi-symmetrical along a longitudinal axis thereof.
4. The windback device of claim 1 , wherein said oblique pitch angles vary between two or more said inclined threads.
5. An apparatus for preventing a lubricant from leaking from a lubricant sump containing a rotatable runner to an annular fluid seal assembly comprising:
an annular seal housing adapted to receive said rotatable runner and forming a cavity between said annular seal housing and said rotatable runner;
an annular flange extending from said annular seal housing and coupling said annular fluid seal assembly to said lubricant sump;
an annular seal sized to substantially surround said rotatable runner and fit within said cavity such that said annular seal isolates said lubricant sump from said cavity; and
an annular windback extending from an inner face along said annular seal housing toward an interior of said lubricant sump wherein said annular windback is co-axial with said rotatable runner, said annular windback including a plurality of ridges defining a plurality of inclined threads oriented circumferentially, each said inclined thread oriented at an oblique pitch angle with respect to a rotational axis of said rotatable runner, any two adjacent said inclined threads partially overlapping along a portion of a circumference of said annular seal housing, each said inclined thread oriented such that said lubricant splashed from said rotatable runner is redirected into said inclined threads, away from said seal, and back into said lubricant sump through a leak-off slot of each respective said inclined thread, wherein a depth along each said ridge varies so as to create a positive incline angle or a negative incline angle from one end of each said inclined thread to another end thereof and between adjacent said inclined threads.
6. The apparatus of claim 5 , wherein said inclined threads are angled toward direction of rotation of said rotatable runner such that windage and sheer forces created by rotation of said rotatable runner direct said lubricant back into said lubricant sump.
7. The apparatus of claim 5 , wherein said ridges are sized and spaced equally along said inner face such that said inclined threads are of an equal width, taper angle and circumferential angle.
8. The apparatus of claim 5 , wherein said ridges are sized and spaced equally along said inner face such that each said inclined thread is bi-symmetrical along a longitudinal axis of said inclined thread.
9. The apparatus of claim 5 , wherein said ridges forming said inclined threads are at different circumferential angles along said inner face and relative to a longitudinal axis of said rotatable runner such that each said inclined thread is of a unique width, taper angle, and circumferential angle.
10. A method of removing a lubricant entering an opening between a windback and a rotatable runner comprising:
redirecting said lubricant entering said opening to a plurality of inclined threads separately spaced along an inner face of said windback using windage created from said rotatable runner, each said inclined thread separately extends from said inner face toward said rotatable runner and oriented circumferentially along said inner face at an oblique pitch angle with respect to a rotational axis of said rotatable runner, any two adjacent said inclined threads partially overlap along a portion of a circumference of said windback, each said inclined thread has a leak-off slot at one end of said windback, wherein a depth along said plurality of inclined threads varies so as to create a positive incline angle or a negative incline angle from one end of each said inclined thread to another end thereof and between adjacent said inclined threads; and
urging said lubricant to travel along said inclined threads away from a seal using shear forces created from said rotatable runner such that said lubricant separately exits said inclined threads through said leak-off slots.
11. The method of claim 10 , wherein said lubricant travels along said inclined threads at an angle relative to a longitudinal axis of said rotatable runner and with direction of rotation of said rotatable runner.
12. A method of preventing a lubricant from contacting a seal surrounding a rotatable runner using a windback that extends from a seal housing coaxially with said rotatable runner toward an interior of a lubricant sump comprising:
redirecting said lubricant entering an opening between said windback and said rotatable runner to a plurality of inclined threads separately spaced along an inner face of said windback using windage created from said rotatable runner, each said inclined thread separately extends from said inner face toward said rotatable runner and oriented circumferentially along said inner face at an oblique pitch angle with respect to a rotational axis of said rotatable runner, any two adjacent said inclined threads partially overlap along a portion of a circumference of said windback, each said inclined thread has a leak-off slot at one end of said windback, wherein a depth along said plurality of inclined threads varies so as to create a positive incline angle or a negative incline angle from one end of each said inclined thread to another end thereof and between adjacent said inclined threads;
urging said lubricant to travel along said inclined threads away from said seal using shear forces created from said rotatable runner such that said lubricant separately exits said inclined threads through said leak-off slots; and
returning said lubricant to said lubricant sump.