Mechanical Seal Including Recovery Port For Use With Pumps

Abstract

A mechanical seal for an axial flow pump may include an annular seal housing configured to be received in a pump housing, the annular seal housing defining a shaft aperture configured for passage therethrough by a pump shaft of the axial flow pump. The annular seal housing may include a second seal housing face at least partially defining an annular first seal recess having a first inner diameter and configured to receive therein an annular stationary seal, such that the annular stationary seal provides a stationary seal against the pump shaft, an annular face seal recess having a second inner diameter greater than the first inner diameter and configured to receive therein a stationary face seal, and a recovery port extending from one or more of the first seal recess or the face seal recess to an exterior of the annular seal housing.

What is claimed is: 
     
         1 . A mechanical seal for an axial flow pump, the mechanical seal comprising:
 an annular seal housing configured to be received in a pump housing, the annular seal housing defining a shaft aperture configured for passage therethrough by a pump shaft of the axial flow pump, the annular seal housing comprising:
 a first seal housing face; 
 a second seal housing face opposite the first seal housing face and at least partially defining:
 an annular first seal recess having a first inner diameter and configured to receive therein an annular stationary seal, such that the annular stationary seal provides a stationary seal against the pump shaft; 
 an annular face seal recess having a second inner diameter greater than the first inner diameter and configured to receive therein a stationary face seal; and 
 a recovery port extending from one or more of the first seal recess or the face seal recess to an exterior of the annular seal housing; 
 
   a stationary seal received in the annular first seal recess;   a stationary face seal received in the annular face seal recess;   an inner sleeve coupled to the annular seal housing and configured to receive therethrough the pump shaft and rotate with the pump shaft, such that the inner sleeve rotates relative to the annular seal housing, the inner sleeve comprising a substantially hollow cylindrical body defining an internal recess configured to receive therein a shaft seal configured to abut the pump shaft and rotate with the pump shaft;   a rotating face seal retainer configured to receive therein a rotating face seal;   a rotating face seal received in the rotating face seal retainer and configured to abut against the stationary face seal and rotate with the pump shaft, such that the stationary face seal and the rotating face seal form a sliding seal interface; and   a biasing member positioned to press the rotating face seal against the stationary face seal.   
     
     
         2 . The mechanical seal of  claim 1 , wherein the recovery port extends radially outward relative to the one or more of the first seal recess or the face seal recess. 
     
     
         3 . The mechanical seal of  claim 1 , wherein the recovery port is positioned such that fluid passing the rotating face seal and the stationary face seal flows into the recovery port and away from the mechanical seal. 
     
     
         4 . The mechanical seal of  claim 1 , further comprising a biasing member retainer radially exterior relative to the biasing member and extending substantially from a first end of the inner sleeve toward the rotating face seal. 
     
     
         5 . The mechanical seal of  claim 4 , wherein the inner sleeve is radially interior relative to the biasing member. 
     
     
         6 . The mechanical seal of  claim 1 , further comprising a preload spacer longitudinally opposite the biasing member relative to the seal housing. 
     
     
         7 . The mechanical seal of  claim 1 , further comprising a shaft collar configured to be coupled to the pump shaft, the shaft collar being longitudinally opposite the biasing member relative to the seal housing. 
     
     
         8 . The mechanical seal of  claim 1 , wherein the seal housing further defines a vent port extending from one or more of the first seal recess or the face seal recess to the exterior of the annular seal housing. 
     
     
         9 . The mechanical seal of  claim 8 , wherein the vent port extends radially outward relative to the one or more of the first seal recess or the face seal recess. 
     
     
         10 . The mechanical seal of  claim 1 , wherein one or more of the annular stationary seal or the shaft seal comprises one or more of an O-ring seal or an energized lip seal. 
     
     
         11 . The mechanical seal of  claim 1 , wherein the recovery port is configured to be in flow communication with a containment chamber associated with the axial flow pump, and wherein pressure in the containment chamber is at a lower pressure than pressure at the discharge passage of the axial flow pump, thereby creating a suction pressure at the recovery port. 
     
     
         12 . The mechanical seal of  claim 1 , wherein the annular stationary seal is configured to provide one or more of a maximum seal pressure ranging from about 30 pounds per square inch (psi) to about 75 psi or a minimum pressure ranging from about minus 5 psi to about minus 40 psi. 
     
     
         13 . An axial flow pump and mechanical seal assembly comprising:
 an axial flow pump configured to pump fluid, the axial flow pump comprising:
 a longitudinal containment chamber; 
 a pump shaft extending longitudinally within the containment chamber; 
 at least one pump housing coupled to an entry end of the pump shaft, such that the pump shaft rotates relative to the at least one pump housing; 
 at least one impeller coupled to the pump shaft and configured to rotate with the pump shaft; and 
 a discharge passage at a discharge end of the axial flow pump opposite the entry end of the pump shaft; and 
   a mechanical seal coupled to the pump shaft opposite the entry end of the pump shaft relative to discharge passage, the mechanical seal comprising:
 an annular seal housing received in one of the at least one pump housings, the annular seal housing defining a shaft aperture through which the pump shaft of the axial flow pump passes, the annular seal housing comprising:
 a first seal housing face; 
 a second seal housing face opposite the first seal housing face and at least partially defining:
 an annular first seal recess having a first inner diameter and configured to receive therein an annular stationary seal, such that the annular stationary seal provides a stationary seal against the pump shaft; 
 an annular face seal recess having a second inner diameter greater than the first inner diameter and configured to receive therein a stationary face seal; and 
 a recovery port extending from one or more of the first seal recess or the face seal recess to an exterior of the annular seal housing; 
 
 
 a stationary seal received in the annular first seal recess; 
 a stationary face seal received in the annular face seal recess; 
 an inner sleeve coupled to the annular seal housing and receiving therethrough the pump shaft and configured to rotate with the pump shaft, such that the inner sleeve rotates relative to the annular seal housing, the inner sleeve comprising a substantially hollow cylindrical body defining an internal recess configured to receive therein a shaft seal configured to abut the pump shaft and rotate with the pump shaft; 
 a rotating face seal retainer configured to receive therein a rotating face seal; 
 a rotating face seal received in the rotating face seal retainer and configured to abut against the stationary face seal and rotate with the pump shaft, such that the stationary face seal and the rotating face seal form a sliding seal interface; and 
 a biasing member positioned to press the rotating face seal against the stationary face seal. 
   
     
     
         14 . The assembly of  claim 13 , wherein the axial flow pump is configured to extend downward into a barge interior, the longitudinal containment chamber defining a port configured to be coupled to a conduit of the barge to receive therethrough fluid from the barge interior. 
     
     
         15 . The assembly of  claim 13 , wherein the axial flow pump comprises a vertical barge pump. 
     
     
         16 . The assembly of  claim 13 , wherein the axial flow pump comprises a mounting flange configured to be coupled to a support surface of a barge. 
     
     
         17 . The assembly of  claim 13 , wherein the recovery port provides fluid flow between the one or more of the first seal recess or the face seal recess to an interior of the longitudinal containment chamber of the axial flow pump. 
     
     
         18 . The assembly of  claim 13 , wherein the seal housing further defines a vent port extending from one or more of the first seal recess or the face seal recess to the exterior of the annular seal housing. 
     
     
         19 . The assembly of  claim 18 , wherein the vent port provides fluid flow between the one or more of the first seal recess or the face seal recess and the barge interior. 
     
     
         20 . The assembly of  claim 13 , wherein the recovery port extends radially outward relative to the one or more of the first seal recess or the face seal recess. 
     
     
         21 . The assembly of  claim 13 , wherein the recovery port is positioned such that fluid passing the rotating face seal and the stationary face seal flows into the recovery port and away from the mechanical seal. 
     
     
         22 . The assembly of  claim 13 , further comprising biasing member retainer radially exterior relative to the biasing member and extending substantially from a first end of the inner sleeve toward the rotating face seal. 
     
     
         23 . The assembly of  claim 22 , wherein the inner sleeve is radially interior relative to the biasing member. 
     
     
         24 . The assembly of  claim 13 , further comprising a preload spacer longitudinally opposite the biasing member relative to the seal housing. 
     
     
         25 . The assembly of  claim 13 , further comprising a shaft collar coupled to the pump shaft, the shaft collar being longitudinally opposite the biasing member relative to the seal housing. 
     
     
         26 . The assembly of  claim 13 , wherein the seal housing further defines a vent port extending from one or more of the first seal recess or the face seal recess to the exterior of the annular seal housing. 
     
     
         27 . The assembly of  claim 26 , wherein the vent port extends radially outward relative to the one or more of the first seal recess or the face seal recess. 
     
     
         28 . The assembly of  claim 13 , wherein one or more of the annular stationary seal or the shaft seal comprises one or more of an O-ring seal or an energized lip seal. 
     
     
         29 . The assembly of  claim 13 , wherein the recovery port is in flow communication with a containment chamber associated with the axial flow pump, and wherein pressure in the containment chamber is at a lower pressure than pressure at the discharge passage of the axial flow pump, thereby creating a suction pressure at the recovery port. 
     
     
         30 . The assembly of  claim 13 , wherein the annular stationary seal is configured to provide one or more of a maximum seal pressure ranging from about 30 pounds per square inch (psi) to about 75 psi or a minimum pressure ranging from about minus 5 psi to about minus 40 psi.