High pressure pump

Abstract

A pump assembly includes a housing, and first and second rotor that are rotatable within the housing and mesh with each other. The pump assembly includes wear plates arranged on opposing sides of the rotors and a separation mechanism that is engageable with the wear plates and enables axial movement of the wear plates relative to the rotors. The wear plates are normally biased to be disengaged from the rotors and axially moveable to engage the rotors when pressure in the pump assembly exceeds a predetermined pressure threshold. The rotors may be lobe gears that each include a plurality of lobes. The lobes may include wiper retaining recesses that retain wiper inserts and the walls of the wiper retaining recesses may have pressure trapping grooves that enable trapped fluid to flow out of the wiper retaining recesses for pressure relief.

1 . A pump assembly comprising:
 a housing;   a first rotor and a second rotor, each rotor rotatably mounted in the housing and meshing with the other rotor;   a plurality of wear plates including a first wear plate arranged on a first side of the rotors and a second wear plate arranged on a second side of the rotors opposite the first side; and   a separation mechanism that is engageable with the plurality of wear plates to enable axial movement of the plurality of wear plates relative to the rotors, the plurality of wear plates being normally disengaged from the rotors and axially moveable to engage the rotors when pressure in the pump assembly exceeds a predetermined pressure threshold.   
     
     
         2 . The pump assembly according to  claim 1 , wherein the separation mechanism includes at least one pre-loaded spring associated with each of the first wear plate and the second wear plate. 
     
     
         3 . The pump assembly according to  claim 1 , wherein the plurality of wear plates have a first position in which the plurality of wear plates are disengaged from the rotors and a second position in which the plurality of wear plates are engaged against the rotors, the plurality of wear plates being biased towards the first position and moveable from the first position towards the second position. 
     
     
         4 . The pump assembly according to  claim 1 , wherein the first rotor and the second rotor are formed of a metal material and the plurality of wear plates are formed of a plastic material. 
     
     
         5 . The pump assembly according to  claim 1 , wherein the rotors are externally toothed gears. 
     
     
         6 . The pump assembly according to  claim 1 , wherein the rotors are lobe gears each having a plurality of lobes and the housing is a lobe gear pump housing in which the rotors are rotatable without contacting each other. 
     
     
         7 . The pump assembly according to  claim 6  further comprising:
 a centrifugal pump housing attached and fluidly connected to the lobe gear pump housing and having an interior chamber; and 
 an impeller that is arranged within the interior chamber centrifugal pump housing and rotatable within the interior chamber, the impeller being configured to pressurize fluid and direct the fluid to the lobe gear pump housing, 
 wherein the plurality of wear plates axially moves to engage the plurality of lobes when pressure in the lobe gear pump housing exceeds a predetermined pressure threshold. 
 
     
     
         8 . The pump assembly according to  claim 7 , further comprising a plurality of wiper inserts, each wiper insert being interconnected to one of the plurality of lobes of each of the first rotor and the second rotor, each wiper insert being depressibly radially biased outward from the lobe of the respective rotor such that the wiper insert can contact the other of the first rotor and the second rotor and the interior chamber of the lobe gear pump housing upon rotation of the first rotor and the second rotor. 
     
     
         9 . The pump assembly according to  claim 8 , wherein each of the plurality of lobes includes a plurality of wiper retaining recesses, each wiper retaining recess being located at an outermost location of a respective lobe, the respective lobe including a longitudinally extending base and opposing walls extending perpendicularly from the longitudinally extending base to define the wiper retaining recess therebetween for retaining the wiper insert. 
     
     
         10 . The pump assembly according to  claim 9 , further comprising a plurality of pressure trapping grooves defined in each of the opposing walls of the respective lobe. 
     
     
         11 . The pump assembly according to  claim 10 , wherein the plurality of pressure trapping grooves includes a first set of pressure trapping grooves defined in a first wall of the opposing walls and a second set of pressure trapping grooves defined in a second wall of the opposing walls, the first set of pressure trapping grooves facing the second set of pressure trapping grooves, wherein the first set and the second set of pressure trapping grooves enable fluid flow out of the wiper retaining recess. 
     
     
         12 . The pump assembly according to  claim 10 , wherein the pressure trapping grooves are evenly spaced along each of the opposing walls. 
     
     
         13 . A pump assembly comprising:
 a first rotor and a second rotor that are each rotatable about a longitudinal rotor axis, each rotor having a plurality of lobes that each have a longitudinal lobe axis that is parallel with the rotor axis, the first and second rotor meshing upon rotation without contacting each other;   a plurality of wiper retaining recesses defined in each of the plurality of lobes, each lobe including a longitudinally extending base and opposing walls that extend radially outwardly from the longitudinally extending base to define the wiper retaining recess, each of the opposing walls having a plurality of pressure trapping grooves that are defined in the opposing walls and extend radially outwardly for pressure relief in the plurality of wiper retaining recesses; and   a plurality of wiper inserts associated with each of the plurality of lobes and retained within the plurality of wiper retaining recesses, each wiper insert being depressibly radially biased outward from the lobe of the rotor such that the wiper can contact the at least one of the other rotor and the interior chamber of the first housing upon rotation of the rotors.   
     
     
         14 . The pump assembly according to  claim 13 , wherein the plurality of pressure trapping grooves includes a first set of pressure trapping grooves defined in a first wall of the opposing walls and a second set of pressure trapping grooves defined in a second wall of the opposing walls, the first set of pressure trapping grooves facing the second set of pressure trapping grooves, wherein the first set and the second set of pressure trapping grooves enable fluid flow out of the wiper retaining recess. 
     
     
         15 . The pump assembly according to  claim 13 , wherein the pressure trapping grooves are evenly spaced along each of the opposing walls. 
     
     
         16 . The pump assembly according to  claim 13 , further comprising at least one wiper spring that biases the wiper insert radially outwardly, the wiper spring being retained within the wiper retaining recess. 
     
     
         17 . The pump assembly according to  claim 13 , further comprising:
 a first housing having an interior chamber, the first rotor and the second rotor being rotatable within the interior chamber of the first housing;   a second housing attached to the first housing and having an interior chamber, the second housing being fluidly connected to the first housing; and   an impeller rotatable within the interior chamber of the second housing.   
     
     
         18 . The pump assembly according to  claim 17 , further comprising:
 a first drive shaft, the first rotor being mounted on and coupled to the first drive shaft;   a first timing gear mounted on and coupled to the first drive shaft;   a second timing gear driven by the first timing gear and mounted on and coupled to a second driven shaft, the second rotor being mounted on and coupled to the second drive shaft; and   a drive motor rotatably driving the first shaft in a first direction or a second direction, the impeller being configured to pressurize fluid and direct the fluid to the inlet of the first housing when the drive motor is rotating the first drive shaft in the first direction.   
     
     
         19 . A pump assembly comprising:
 a drive motor rotatably driving a first drive shaft in a first direction or a second direction;   a first timing gear mounted on and coupled to the first drive shaft;   a second timing gear driven by the first timing gear and mounted on and coupled to a second driven shaft;   a first rotor and a second rotor, each rotor having a plurality of lobes, the first rotor and the second rotor being rotatable without contacting each other, the first rotor being mounted on and coupled to the first drive shaft and the second rotor being mounted on and coupled to the second drive shaft;   a lobe gear pump housing having an interior chamber in which the first rotor and second rotor are rotatable;   a plurality of wear plates including a first wear plate arranged on a first side of the plurality of lobes and a second wear plate arranged on a second side of the plurality of lobes opposite the first side; and   a separation mechanism that is engageable with the plurality of wear plates to enable axial movement of the plurality of wear plates relative to the plurality of lobes, the plurality of wear plates being normally disengaged from the plurality of lobes and axially moveable to engage the plurality of lobes when pressure in the lobe gear pump housing exceeds a predetermined pressure threshold.   
     
     
         20 . The pump assembly according to  claim 19 , further comprising:
 a plurality of wiper retaining recesses defined by walls of each of the plurality of lobes, each of the plurality of wiper retaining recesses having a plurality of pressure trapping grooves that are defined in the walls to enable pressure relief within the plurality of wiper retaining recesses;   a plurality of wiper inserts associated with each of the plurality of lobes and retained within the plurality of wiper retaining recesses,   a centrifugal pump housing attached and fluidly connected to the lobe gear pump housing and having an interior chamber; and   an impeller that is arranged within the interior chamber centrifugal pump housing and rotatable within the interior chamber, the impeller being configured to pressurize fluid and direct the fluid to the lobe gear pump housing.   
     
     
         21 . (canceled)