Safety Hydraulic Dump for a Cryogenic Pump

Abstract

A cryogenic fluid pump includes a drive assembly and a pumping assembly. The drive assembly includes a cylinder. The cylinder includes an annular dump channel formed in and extending about an interior wall of the cylinder. A piston is reciprocatable within the cylinder between a first and second position. A hydraulic pressure chamber is defined by the cylinder and the piston. The piston includes an axial spill passage in communication with the pressure chamber and a transverse spill passage in communication with the axial spill passage. The transverse spill passage includes a piston dump port which is sealed to the cylinder in the first position and in the second position unsealed to the cylinder to permit fluid exit from the pressure chamber. The second position includes an over travel state and the dump area of the piston dump port when unsealed to the cylinder increases as the piston advances.

1 . A cryogenic fluid pump, comprising:
 a drive assembly and a pumping assembly, the drive assembly including a cylinder, the cylinder including an annular dump channel that is formed in and extends about an interior wall of the cylinder;   a piston reciprocatable within the cylinder between a first position and a second position; and   a hydraulic pressure chamber defined by the cylinder and the piston;   the piston including at least one axial spill passage in communication with the hydraulic pressure chamber and a transverse spill passage in communication with the at least one axial spill passage, the transverse spill passage including a piston dump port, the piston dump port sealed to the cylinder in the first position and in the second position unsealed to the cylinder to permit fluid exit from the hydraulic pressure chamber, wherein the second position includes an over travel state and wherein the dump area of the piston dump port unsealed to the cylinder continues to increase as the piston advances in the over travel state.   
     
     
         2 . The cryogenic fluid pump of  claim 1 , wherein the piston dump port is in communication with the annular dump channel in the second position. 
     
     
         3 . The cryogenic fluid pump of  claim 2 , wherein the at least one axial spill passage extends less than half the axial length of the piston. 
     
     
         4 . The cryogenic fluid pump of  claim 1 , wherein the at least one axial spill passage includes a pair of axial spill passages. 
     
     
         5 . The cryogenic fluid pump of  claim 1 , wherein the piston includes a transverse width and the transverse spill passage extends the entire transverse width of the piston. 
     
     
         6 . The cryogenic fluid pump of  claim 1 , wherein the annular dump channel is a rectangular groove. 
     
     
         7 . The cryogenic fluid pump of  claim 1 , wherein the at least one axial spill passage extends more than half the axial length of the piston. 
     
     
         8 . The cryogenic fluid pump of  claim 7 , wherein the piston dump port clears an end portion of the cylinder in the second position, wherein the second position corresponds to greater than or equal to 100 percent of an end of stroke position. 
     
     
         9 . The cryogenic fluid pump of  claim 8 , wherein a top of the piston clears the annular dump channel permitting fluid to exit from the hydraulic pressure chamber directly into the annular dump channel, wherein the second position includes the over travel state. 
     
     
         10 . The cryogenic fluid pump of  claim 1 , wherein the piston dump port includes one of a triangular cross section and a U-shaped cross section. 
     
     
         11 . A pumping system for providing a cryogenic fluid for use as a fuel for an engine, comprising:
 an electronic controller;   a cryogenic pump operably associated with the electronic controller, wherein operation of the cryogenic pump is responsive to pump commands from the electronic controller; the cryogenic pump having a plurality of pumping elements, each of the plurality of pumping elements comprising:   a drive assembly and a pumping assembly, the pumping assembly operably responsive to the drive assembly, the drive assembly including a cylinder, the cylinder including an annular dump channel that is formed in and extends about an interior wall of the cylinder;   a piston reciprocatable within the cylinder between a first position and a second position; and   a hydraulic pressure chamber defined by the cylinder and the piston;   the piston including at least one axial spill passage in communication with the hydraulic pressure chamber and a transverse spill passage in communication with the at least one axial spill passage, the transverse spill passage including a piston dump port, the piston dump port sealed to the cylinder in the first position and in the second position unsealed to the cylinder to permit fluid exit from the hydraulic pressure chamber, wherein the second position includes an over travel state and wherein the dump area of the piston dump port unsealed to the cylinder continues to increase as the piston advances in the over travel state.   
     
     
         12 . The cryogenic fluid pump of  claim 11 , wherein the piston dump port is in communication with the annular dump channel in the second position. 
     
     
         13 . The cryogenic fluid pump of  claim 12 , wherein the at least one axial spill passage extends less than half the axial length of the piston. 
     
     
         14 . The cryogenic fluid pump of  claim 11 , wherein the at least one axial spill passage includes a pair of axial spill passages. 
     
     
         15 . The cryogenic fluid pump of  claim 11 , wherein the piston includes a transverse width and the transverse spill passage extends the entire transverse width of the piston. 
     
     
         16 . The cryogenic fluid pump of  claim 11 , wherein the at least one axial spill passage extends more than half the axial length of the piston. 
     
     
         17 . The cryogenic fluid pump of  claim 16 , wherein the piston dump port clears an end portion of the cylinder in the second position, wherein the second position corresponds to greater than or equal to 100 percent end of an end of stroke position. 
     
     
         18 . The cryogenic fluid pump of  claim 17 , wherein a top of the piston clears the annular dump channel permitting fluid to exit from the hydraulic pressure chamber directly into the annular dump channel, wherein the second position includes the over stroke state. 
     
     
         19 . The cryogenic fluid pump of  claim 11 , wherein the piston dump port is includes one of a triangular cross section and a U-shaped cross section. 
     
     
         20 . A cryogenic fluid pump, comprising:
 a plurality of pumping elements in communication with an electronic controller, each of the pumping elements including:   a drive assembly including an electromechanical actuator having a pin associated therewith, the pin arranged in a bore having a fluid supply passage, a spool valve supply outlet, and a drain outlet, wherein the pin is moveable between a deactivation position, in which the hydraulic oil supply passage is fluidly connected with the spool valve supply outlet, and an activation position, in which the spool valve supply outlet is fluidly connected with the drain outlet;   the drive assembly including a cylinder, the cylinder including an annular dump channel that is formed in and extends about an interior wall of the cylinder, a piston reciprocatable within the cylinder between a first position and a second position, and a hydraulic pressure chamber defined by the cylinder and the piston, the piston including at least one axial spill passage in communication with the hydraulic pressure chamber and a transverse spill passage in communication with the at least one axial spill passage, the transverse spill passage including a piston dump port, the piston dump port sealed to the cylinder in the first position and in the second position unsealed to the cylinder to permit fluid exit from the hydraulic pressure chamber, wherein the second position includes an over travel state and wherein the dump area of the piston dump port unsealed to the cylinder continues to increase as the piston advances in the over travel state;   the drive assembly associated with and configured to selectively activate one end of a pushrod in response to a command by the electronic controller; and   a pump assembly associated with an opposite end of the pushrod wherein the pump assembly is activated for pumping a fluid by the drive assembly;   wherein the electronic controller is configured to selectively activate the drive assembly such that a flow of fluid from the cryogenic fluid pump results from successive activations thereof at selected dwell times between activations.