Low and reverse pressure application hydrodynamic pressurizing seals

Abstract

The present invention relates to circumferential seal ring segments positioned around a rotating shaft so as to prevent fluids from leaking from a lubricant sump during both low and high pressure conditions. The circumferential seal is comprised of a plurality of adjoining annular ring segments facing the rotating shaft. Each sealing ring segment includes a dead end circumferential groove on a shaft-side face of each sealing ring such that, when the segments are joined, the circumferential dead end groove of each segment extends arcuately in the direction of shaft rotation. At least one additional groove is contained on the shaft-side face of each sealing ring segment. The additional groove(s) directs and creates pressurized air within the dead end circumferential groove, either directly or indirectly maintaining a seal between the ring segments and the shaft. A bleed hole may also be provided to create a seal between each sealing segment.

1 . A seal assembly for sealing a liquid region from a gas region across an annular surface of a rotating shaft comprising:
 a plurality of adjoining annularly sealing ring segments facing the rotating shaft wherein each sealing ring segment includes a dead end circumferential groove machined within a shaft-side face of each sealing ring segment such that, when the segments are joined about the shaft surface, the circumferential dead end groove of each segment extends arcuately in the direction of shaft rotation; and   at least one additional groove extending across the shaft-side face of each sealing ring segment leading to the dead end circumferential groove wherein the additional groove(s) is in fluid communication with the dead end circumferential groove and directs fluid into the dead end circumferential groove.   
   
   
       2 . The assembly of  claim 1  further comprising a bleed hole extending from the dead end circumferential groove to a joint between adjoining sealing ring segments such that the dead end circumferential groove is in fluid communication with the joint and fluid flow is directed into the joint by way of the bleed hole. 
   
   
       3 . The assembly of  claim 1  wherein the additional groove(s) may be selected from the group consisting of a hydrodynamic inclined groove, a hydrodynamic shallow pocket, and an axial bore groove. 
   
   
       4 . The assembly of  claim 3  wherein the additional groove(s) is a hydrodynamic inclined pumping groove oriented at an oblique pitch angle relative to the longitudinal axis of the ring seal segment and in concert with the direction of rotation of the rotating shaft so as to direct fluid flow generated from the rotating shaft into the dead end circumferential groove. 
   
   
       5 . The assembly of  claim 4  in which the inclined groove has constant width. 
   
   
       6 . The assembly of  claim 4  wherein the inclined groove has constant depth. 
   
   
       7 . The assembly of  claim 4  wherein the inclined groove has a variable depth. 
   
   
       8 . The assembly of  claim 4  wherein the inclined groove has a depth that is greater at a groove mouth than at a position of communication with the dead end groove. 
   
   
       9 . The assembly of  claim 4  wherein the ring seal segment is comprised of more than one hydrodynamic inclined thread wherein each inclined thread has a unique depth. 
   
   
       10 . The assembly of  claim 4  wherein the inclined groove is wider and deeper at a mouth of the groove than at a position of communication with the dead end circumferential groove. 
   
   
       11 . The assembly of  claim 3  wherein the additional groove(s) is comprised of a hydrodynamic shallow pocket having a pocket, an inlet extending from the pocket away from the dead end circumferential groove, and an outlet extending from the pocket toward the dead end circumferential groove wherein the hydrodynamic shallow pocket, by way of the outlet, is in fluid communication with the dead end circumferential groove so as to direct fluid flow generated from a rotating shaft into the dead end circumferential groove. 
   
   
       12 . The assembly of  claim 11  wherein the pocket, inlet and outlet are of uniform and constant depth. 
   
   
       13 . The assembly of  claim 11  wherein the pocket, inlet and outlet are each of variable depths. 
   
   
       14 . The assembly of  claim 11  wherein the pockets are deeper proximate the inlet than at the outlet. 
   
   
       15 . The assembly of  claim 11  further comprising a dam extending between the pocket and the outlet groove. 
   
   
       16 . The assembly of  claim 15  further comprising a bleed slot passing through the dam and from the outlet to the dead end circumferential groove. 
   
   
       17 . The assembly of  claim 11  wherein the inlet and outlet grooves are inclined and in concert with the direction of rotation of the rotating shaft. 
   
   
       18 . The assembly of  claim 3  wherein the additional groove(s) is comprised of an axial bore groove extending perpendicularly to a longitudinal axis of the seal ring segment in fluid communication with the dead end circumferential groove so as to direct fluid flow generated from a rotating shaft into the dead end circumferential groove. 
   
   
       19 . The assembly of  claim 18  wherein the axial bore groove is in direct fluid communication with the dead end circumferential groove. 
   
   
       20 . The assembly of  claim 18  wherein the axial bore groove is in fluid communication with the dead end circumferential groove by way of a first longitudinal bore groove extending from the axial groove and along the longitudinal axis of the ring seal segment to a first pressure chamber wherein the pressure chamber is in fluid communication with the dead end circumferential groove such that fluid flow into the axial groove is directed into the dead end circumferential groove by way of the axial groove, the first longitudinal bore groove and the first pressure chamber. 
   
   
       21 . The assembly of  claim 20  wherein the first longitudinal bore groove contains at least one hydrodynamic groove on an inner surface of the longitudinal bore groove wherein the hydrodynamic groove(s) extends along the longitudinal bore groove at an oblique angle with respect to the longitudinal axis of the longitudinal bore and is angled such that the hydrodynamic groove directs air from the axial groove into the pressure chamber. 
   
   
       22 . The assembly of  claim 20  further comprising a second longitudinal bore groove extending from the axial groove and along the longitudinal axis of the ring seal segment to a second pressure chamber wherein the second pressure chamber is in fluid communication with a joint between adjoining sealing ring segments such that fluid flow is directed into the joint by way of the axial groove, the second longitudinal bore and the second pressure chamber. 
   
   
       23 . The assembly of  claim 22  wherein the second longitudinal bore groove contains at least one hydrodynamic groove on an inner surface of the longitudinal bore groove wherein the hydrodynamic groove(s) extends along the longitudinal bore groove at an oblique angle with respect to the longitudinal axis of the longitudinal bore groove and is angled such that the hydrodynamic groove directs air from the axial groove into the second pressure chamber. 
   
   
       24 . The assembly of  claim 20  further comprising a dam extending between the pressure chamber and the dead end circumferential groove. 
   
   
       25 . The assembly of  claim 24  further comprising a bleed slot passing through the dam from the pressure chamber to the dead end circumferential groove. 
   
   
       26 . The assembly of  claim 3  wherein the additional groove(s) is comprised of a first and a second axial bore groove extending perpendicularly to a longitudinal axis of the seal ring segment in fluid communication with the dead end circumferential groove so as to direct fluid flow generated from a rotating shaft into the dead end circumferential groove wherein the first axial bore groove is spaced at one end of the seal segment and the second axial bore groove is approximately centered on the seal segment. 
   
   
       27 . The assembly of  claim 26  wherein the first axial bore groove is in fluid communication with the dead end circumferential groove by way of a first longitudinal bore groove extending from the first axial groove and along the longitudinal axis of the ring seal segment to a first pressure chamber wherein the first pressure chamber is in fluid communication with the dead end circumferential groove such that fluid flow into the first axial groove is directed into the dead end circumferential groove by way of the first axial groove, the first longitudinal bore groove and the first pressure chamber and the second axial bore groove is in fluid communication with the dead end circumferential groove by way of a second longitudinal bore groove extending from the second axial groove and along the longitudinal axis of the ring seal segment to a second pressure chamber wherein the second pressure chamber is in fluid communication with the dead end circumferential groove such that fluid flow into the axial groove is directed into the dead end circumferential groove by way of the second axial groove, the second longitudinal bore groove and the second pressure chamber. 
   
   
       28 . The assembly of  claim 27  wherein the first pressure chamber is juxtaposed to the second axial groove. 
   
   
       29 . The assembly of  claim 7  wherein the first longitudinal bore groove contains at least one hydrodynamic groove on an inner surface of the longitudinal bore groove wherein the hydrodynamic groove(s) extends along the longitudinal bore groove at an oblique angle with respect to the longitudinal axis of the longitudinal bore and is angled such that the hydrodynamic groove directs air from the first axial groove into the first pressure chamber. 
   
   
       30 . The assembly of  claim 27  wherein the second longitudinal bore groove contains at least one hydrodynamic groove on an inner surface of the longitudinal bore groove wherein the hydrodynamic groove(s) extends along the second longitudinal bore groove at an oblique angle with respect to the longitudinal axis of the second longitudinal bore and is angled such that the hydrodynamic groove directs air from the second axial groove into the second pressure chamber. 
   
   
       31 . The assembly of  claim 27  further comprising a bleed hole extending from the dead end circumferential groove to a joint between adjoining sealing ring segments such that the dead end circumferential groove is in fluid communication with the joint and fluid flow is directed into the joint by way of the bleed hole. 
   
   
       32 . A method of sealing a liquid region from a gas region across an annular surface of a rotating shaft utilizing a plurality of adjoining annularly sealing ring segments facing the rotating shaft, each sealing ring segment having a dead end circumferential groove formed within a shaft-side face of each sealing ring segment at a position closer to the liquid region than to the gas region such that, when the segments are positioned proximate the shaft surface, the circumferential dead end groove of each segment extends arcuately in the direction of shaft rotation, and at least one additional groove formed on the shaft-side face of each sealing ring segment wherein the additional groove(s) is in fluid communication with the dead end circumferential groove comprising;
 directing fluid flow generated by the rotating shaft along the additional groove(s) and into the dead end circumferential groove such that the fluid is pressured as it flows along the additional groove(s) and into the dead end circumferential groove; and   creating an air seal around the rotating shaft as the pressurized air within the dead end circumferential groove is urged toward the rotating shaft.   
   
   
       33 . The method of  claim 32  further comprising redirecting pressurized air from the dead end circumferential groove to a joint between adjoining sealing ring segments through a bleed slot such that the force of the pressured air is also exerted on the joint between adjoining sealing ring segments, thereby created an air seal within the joint and between the adjoining sealing ring segments. 
   
   
       34 . The method of  claim 32  further comprising directing fluid flow generated by the rotating shaft along the additional groove(s) and into the dead end circumferential groove by way of at least one longitudinal bore groove and pressure chamber. 
   
   
       35 . The method of  claim 34  further comprising redirecting pressurized air from the pressure chamber into a joint between adjoining sealing ring segments through a bleed slot such that the force of the pressurized air is also exerted on a joint between adjoining sealing ring segments, thereby within the joint and between the adjoining sealing ring segments. 
   
   
       36 . A method of sealing a liquid region from a gas region across an annular surface of a rotating shaft utilizing a plurality of adjoining annularly sealing ring segments facing the rotating shaft, each sealing ring segment having a dead end circumferential groove formed within a shaft-side face of each sealing ring segment at a position closer to the liquid region than to the gas region such that, when the segments are positioned proximate the shaft surface, the circumferential dead end groove of each segment extends arcuately in the direction of shaft rotation, and at least one additional groove, selected from the group consisting of a hydrodynamic inclined groove, a hydrodynamic shallow pocket, and an axial bore groove, formed on the shaft-side face of each sealing ring segment wherein the additional groove(s) is in fluid communication with the dead end circumferential groove comprising;
 urging the sealing ring segments toward the shaft such that the sealing ring segments from a seal with the shaft when the shaft is not rotating;   rotating the shaft;   directing fluid flow generated by the rotating shaft along the additional groove(s) and into the dead end circumferential groove such that the fluid is pressured as it flows along the additional groove(s) and into the dead end circumferential groove;   redirecting the pressurized fluid within the dead end circumferential groove toward the rotating shaft so as to provide a lift force on the seal segments that lifts the seal segments away from the rotating shaft; and   creating an air seal around the rotating shaft as the pressurized air within the dead end circumferential groove is urged toward the rotating shaft, thereby, maintaining a seal between the shaft and the sealing ring segments during rotation and non-rotation of the shaft.   
   
   
       37 . The method of  claim 36  further comprising redirecting pressurized air from the dead end circumferential groove to a joint between adjoining sealing ring segments through a bleed slot such that the force of the pressured air is also exerted on the joint between adjoining sealing ring segments, thereby created an air seal within the joint and between the adjoining sealing ring segments. 
   
   
       38 . The method of  claim 36  further comprising directing fluid flow generated by the rotating shaft along the additional groove(s) and into the dead end circumferential groove by way of at least one longitudinal bore groove and pressure chamber. 
   
   
       39 . The method of  claim 38  further comprising redirecting pressurized air from the pressure chamber into a joint between adjoining sealing ring segments through a bleed slot such that the force of the pressurized air is also exerted on a joint between adjoining sealing ring segments, thereby created an air seal within the joint and between the adjoining sealing ring segments. 
   
   
       40 . A seal assembly for sealing a liquid region from a gas region across an annular surface of a rotating shaft comprising:
 a plurality of adjoining annularly sealing ring segments facing the rotating shaft wherein each sealing ring segment includes a dead end circumferential groove machined within a shaft-side face of each sealing ring segment such that, when the segments are joined about the shaft surface, the circumferential dead end groove of each segment extends arcuately in the direction of shaft rotation; and   at least one additional groove extending across the shaft-side face of each sealing ring segment leading to the dead end circumferential groove wherein the additional groove(s) is in fluid communication with the dead end circumferential groove and directs fluid into the dead end circumferential groove wherein the additional groove is a hydrodynamic inclined pumping groove oriented at an oblique pitch angle relative to the longitudinal axis of the ring seal segment and in conceit with the direction of rotation of the rotating shaft so as to direct fluid flow generated from the rotating shaft into the dead end circumferential groove.   
   
   
       41 . A seal assembly for sealing a liquid region from a gas region across an annular surface of a rotating shaft comprising:
 a plurality of adjoining annularly sealing ring segments facing the rotating shaft wherein each sealing ring segment includes a dead end circumferential groove machined within a shaft-side face of each sealing ring segment such that, when the segments are joined about the shaft surface, the circumferential dead end groove of each segment extends arcuately in the direction of shaft rotation; and   at least one additional groove extending across the shaft-side face of each sealing ring segment leading to the dead end circumferential groove wherein the additional groove(s) is in fluid communication with the dead end circumferential groove and directs fluid into the dead end circumferential groove wherein the additional groove(s) is comprised of a hydrodynamic shallow pocket having a pocket, an inlet extending from the pocket away from the dead end circumferential groove, and an outlet extending from the pocket toward the dead end circumferential groove wherein the hydrodynamic shallow pocket, by way of the outlet, is in fluid communication with the dead end circumferential groove so as to direct fluid flow generated from a rotating shaft into the dead end circumferential groove.   
   
   
       42 . A seal assembly for sealing a liquid region from a gas region across an annular surface of a rotating shaft comprising:
 a plurality of adjoining annularly sealing ring segments facing the rotating shaft wherein each sealing ring segment includes a dead end circumferential groove machined within a shaft-side face of each sealing ring segment such that, when the segments are joined about the shaft surface, the circumferential dead end groove of each segment extends arcuately in the direction of shaft rotation; and   at least one additional groove extending across the shaft-side face of each sealing ring segment leading to the dead end circumferential groove wherein the additional groove(s) is in fluid communication with the dead end circumferential groove and directs fluid into the dead end circumferential groove wherein the additional groove is at least one axial bore groove extending perpendicularly to a longitudinal axis of the seal ring segment in fluid communication with the dead end circumferential groove so as to direct fluid flow generated from a rotating shaft into the dead end circumferential groove wherein the axial bore groove is in direct fluid communication with the dead end circumferential groove.   
   
   
       43 . A seal in an assembly for sealing a liquid region from a gas region across an annular surface of a rotating shaft comprising:
 a plurality of adjoining annularly sealing ring segments facing the rotating shaft wherein each sealing ring segment includes a dead end circumferential groove machined within a shaft-side face of each sealing ring segment such that, when the segments are joined about the shaft surface, the circumferential dead end groove of each segment extends arcuately in the direction of shaft rotation; and   at least one additional groove extending across the shaft-side face of each sealing ring segment leading to the dead end circumferential groove wherein the additional groove(s) is in fluid communication with the dead end circumferential groove and directs fluid into the dead end circumferential groove wherein the additional groove is at least one axial bore groove extending perpendicularly to a longitudinal axis of the seal ring segment in fluid communication with the dead end circumferential groove so as to direct fluid flow generated from a rotating shaft into the dead end circumferential groove wherein the axial bore groove is in fluid communication with the dead end circumferential groove by way of a first longitudinal bore groove extending from the axial groove and along the longitudinal axis of the ring seal segment to a first pressure chamber wherein the pressure chamber is in fluid communication with the dead end circumferential groove such that fluid flow into the axial groove is directed into the dead end circumferential groove by way of the axial groove, the first longitudinal bore groove and the first pressure chamber the first longitudinal bore groove contains at least one hydrodynamic groove on an inner surface of the longitudinal bore groove wherein the hydrodynamic groove(s) extends along the longitudinal bore groove at an oblique angle with respect to the longitudinal axis of the longitudinal bore and is angled such that the hydrodynamic groove directs air from the axial groove into the pressure chamber.