Pump system with integrated piston-valve actuation

Abstract

A pump system includes a pump chamber and piston. The chamber has a cylindrical wall, an inlet port and a discharge port, both disposed in the wall axially spaced from the closed end and circumferentially spaced from each other. The piston is disposed in the pump chamber for reciprocating and rotational movement. The piston has at least one channel formed therein that is aligned with the inlet port during an intake stroke and is rotated out of alignment with the inlet port during a discharge stroke. The drive system includes a motor, a threaded shaft coupled to the motor and a coupling assembly coupling the shaft to the piston. The coupling assembly is configured to linearly move the piston when the piston is rotationally constrained and to rotationally move the piston when the piston is linearly constrained.

1 . A pump system comprising:
 a pump chamber having a cylindrical wall having a length and a closed end,   an inlet port disposed in the wall axially spaced from the closed end and a discharge port disposed in the wall axially spaced from the closed end and circumferentially spaced from the inlet port;   a piston disposed in the pump chamber and configured for reciprocating movement and rotational movement, the piston having a channel formed therein, the channel extending generally axially from an end thereof, the channel being aligned with the inlet port during an intake stroke and being aligned with the discharge port during a discharge stroke;   a drive system including a motor and a threaded shaft and a coupling assembly coupling the motor to the piston, the coupling assembly configured to linearly move the piston when the piston is rotationally constrained and to rotationally move the piston when the piston is linearly constrained;   means for selectively linearly restraining the piston to effect rotational movement of the piston; and   means for selectively rotationally retraining the piston to effect linear movement of the piston.   
   
   
       2 . The pump system in accordance with  claim 1  wherein the threaded shaft is mounted to the motor and the coupling assembly is disposed at the piston. 
   
   
       3 . The pump system in accordance with  claim 1  wherein the pump chamber and piston are ceramic. 
   
   
       4 . The pump system in accordance with  claim 1  including a cam follower operably connected to the piston. 
   
   
       5 . The pump system in accordance with  claim 4  wherein the means for selectively rotationally restraining the piston includes a track defining a linear path, and wherein the cam follower moves in the track and is restrained from rotational movement by the track. 
   
   
       6 . The pump system in accordance with  claim 1  wherein the means for selectively linearly restraining the piston includes a rotating ring at an end of one of the intake stroke and the discharge stroke, the rotating ring receiving the cam follower, the cam follower rotating with the ring and restrained from linear movement by the ring. 
   
   
       7 . The pump system in accordance with  claim 6  including a ring at the end of the intake stroke and a ring at the end of the discharge stroke. 
   
   
       8 . The pump system in accordance with  claim 7  including rings at the end of the intake stroke and at the end of the discharge stroke. 
   
   
       9 . The pump system in accordance with  claim 6  including two cam followers circumferentially spaced 180 degrees apart, and wherein the rotating ring includes two recesses circumferentially spaced 180 degrees to receive the cam followers when the piston is at the end of the intake or discharge stroke. 
   
   
       10 . The pump system in accordance with  claim 7  including two cam followers circumferentially spaced 180 degrees apart, and wherein the rotating rings each include two recesses circumferentially spaced 180 degrees to receive the cam followers when the piston is at the end of the intake and discharge strokes, respectively, and wherein the means for selectively rotationally restraining the piston includes a track defining a linear path and extending between the rings, and wherein the cam follower moves in the track and is restrained from rotational movement by the track. 
   
   
       11 . The pump system in accordance with  claim 10  wherein the track is a first track, and including a second track parallel to the first track, the first and second tracks configured to receive the cam followers and to restrain the cam followers from rotational movement. 
   
   
       12 . The pump system in accordance with  claim 8  including a one-way clutch associated with each of the rings, the one-way clutches permitting the rings to rotate in opposite directions. 
   
   
       13 . The pump system in accordance with  claim 1  wherein the drive system coupling assembly is a ball screw. 
   
   
       14 . A pump system comprising:
 a pump chamber having a cylindrical wall having a length and a closed end, the chamber having an inlet port disposed in the wall axially spaced from the closed end and a discharge port disposed in the wall axially spaced from the closed end, the inlet and discharge ports spaced about equally from the closed end and circumferentially spaced from one another;   a piston disposed in the pump chamber and configured for reciprocating movement and rotational movement, the piston having a channel formed therein, the channel extending generally axially from an end thereof to a termination along a length of the piston, the channel being aligned with the inlet port during an intake stroke and aligned with the discharge port during a discharge stroke, the piston reciprocating such that the channel termination is about aligned with the inlet or discharge port when the piston is at the end of the discharge stroke;   a drive system including a motor and a threaded shaft coupled to the motor, the drive system including a screw coupling assembly disposed at the piston coupling the threaded shaft to the piston, the coupling configured to linearly and rotationally move the piston;   a cam follower operably connected to the piston;   a linear track configured to receive the cam follower as the piston moves between the end of the discharge stroke and the end of the intake stroke; and   first and second one-way rotating cam receiving elements disposed at opposing ends of the tracks to engage the cam follower when the piston is at the end of the discharge and intake strokes, respectively, the one-way rotating cam receiving elements rotating in opposite directions,   wherein when the piston is at the end of the discharge stroke with the piston channel aligned with the discharge port, the motor rotates and the first one-way rotating cam receiving element permits rotational movement of the piston to align the channel with the inlet port, the motor reverses direction and the first one-way rotating cam receiving element prevents reverse rotational movement and the screw coupling permits linear movement of the piston with the cam follower in the linear track, the piston withdrawing from the pump chamber until the cam follower engages the second one-way rotating cam receiving element to stop linear movement and translate movement to rotational movement to rotate the piston and align the channel with the discharge port, the motor reversing direction and the second one-way rotating cam receiving element prevents rotational movement and screw coupling permits linear movement of the piston with the cam follower in the linear track, the piston inserting into the pump chamber until the cam follower engages the first one-way rotating cam receiving element.   
   
   
       15 . The pump system in accordance with  claim 14  wherein the pump chamber and piston are ceramic. 
   
   
       16 . The pump system in accordance with  claim 14  including two cam followers circumferentially spaced 180 degrees apart, and wherein the rotating cam receiving elements each include two recesses circumferentially spaced 180 degrees to receive the cam followers when the piston is at the end of the intake and discharge strokes, respectively. 
   
   
       17 . The pump system in accordance with  claim 16  including two linear tracks defining parallel to one another and circumferentially spaced from one another, the linear tracks extending between the rotating cam receiving elements, and wherein the cam followers move in the tracks and are restrained from rotational movement by the tracks. 
   
   
       18 . The pump system in accordance with  claim 14  wherein the pump is seal-less. 
   
   
       19 . A pump system comprising:
 a pump chamber having a cylindrical wall having a length and a closed end,   an inlet port disposed in the wall axially spaced from the closed end and a discharge port disposed in the wall axially spaced from the closed end and circumferentially spaced from the inlet port;   a piston disposed in the pump chamber, the piston configured to reciprocate and rotate within the chamber, the piston having an inlet channel formed therein for cooperating with the inlet port and a discharge channel formed therein for cooperating with the discharge port, the channels each extending in a curved profile from a common end of the piston, the inlet channel being aligned with the inlet port during an intake stroke and the discharge channel being aligned with the discharge port during a discharge stroke, the inlet port and discharge port and inlet channel and discharge channel are positioned such that only one port can be aligned with its respective channel at a time; and   a drive system including a motor operably coupled to the piston, the motor configured to reciprocate the piston within the cylinder to effect inlet or discharge and to rotate the piston between aligning the inlet port with the inlet channel during an inlet portion of a pump cycle and aligning the discharge port with the discharge channel during a discharge portion of the pump cycle.   
   
   
       20 . The pump system in accordance with  claim 19  wherein the piston resides in the pump chamber without a seal therebetween. 
   
   
       21 . The pump system in accordance with  claim 19  wherein including a cam follower operably mounted to the piston and a track defining a cam surface for guiding the cam follower. 
   
   
       22 . The pump system in accordance with  claim 21  wherein the track has a substantially oval shape. 
   
   
       23 . The pump system in accordance with  claim 22  wherein the oval has substantially flattened ends. 
   
   
       24 . The pump system in accordance with  claim 19  wherein during a transition between the intake stroke and the discharge stroke and during a transition between the discharge stroke and the intake stroke, the piston is constrained from reciprocating and substantially only rotates. 
   
   
       25 . The pump system in accordance with  claim 19  wherein the inlet and discharge ports are disposed at an angle relative to one another greater than zero degrees and less than or equal to 180 degrees. 
   
   
       26 . A pump system comprising:
 a pump chamber;   an inlet port disposed in a wall of the pump chamber and a discharge port disposed in the wall of the pump chamber spaced from the inlet port;   a piston disposed in the pump chamber and configured for reciprocating movement and rotational movement, the piston having a channel formed therein aligned with the inlet port during an intake stroke and being rotated out of alignment with the inlet port during a discharge stroke;   a drive system including a single motor operably coupled to the piston to linearly move the piston in the intake and discharge strokes and to rotate the piston to align the channel and inlet port during an intake stroke and to rotate the channel out of alignment with the inlet port during a discharge stroke.   
   
   
       27 . The pump system in accordance with  claim 26  wherein the piston channel is in alignment with the discharge port during the discharge stroke. 
   
   
       28 . The pump system in accordance with  claim 26  wherein the piston channel is an inlet channel and wherein the piston includes a discharge channel that is in alignment with the discharge port during the discharge stroke. 
   
   
       29 . A form, fill and seal packaging machine of the type for forming, filling and sealing a package, comprising:
 a pump system having a ceramic pump chamber having a cylindrical wall having a length and a closed end, the pump chamber having an inlet port disposed in the wall axially spaced from the closed end and a discharge port disposed in the wall axially spaced from the closed end and circumferentially spaced from the inlet port, the pump system including a ceramic piston disposed in the pump chamber and configured for reciprocating movement and rotational movement, the piston having a channel formed therein, the channel extending generally axially from an end thereof, the channel being aligned with the inlet port during an intake stroke and being out of alignment with the discharge port during the inlet stroke, the pump system further including a drive system including a motor and a threaded shaft coupled to the motor, the drive system including a coupling assembly coupling the threaded shaft to the piston, the coupling assembly configured to linearly move the piston when the piston is rotationally constrained and to rotationally move the piston when the piston is linearly constrained, the pump system having means for selectively linearly restraining the piston to effect rotational movement of the piston and means for selectively rotationally retraining the piston to effect linear movement of the piston.   
   
   
       30 . The form, fill and seal packaging machine in accordance with  claim 29  wherein the piston includes a cam follower mounted thereto and wherein the means for selectively rotationally restraining the piston includes a track defining a linear path, and wherein the cam follower moves in the track and is restrained from rotational movement by the track. 
   
   
       31 . The form, fill and seal packaging machine in accordance with  claim 30  wherein the means for selectively linearly restraining the piston includes a rotating ring at an end of the intake stroke and the discharge stroke, the rotating rings receiving the cam follower, the rotating rings being rotating in one direction only and rotating in opposite directions from one another, the cam follower rotating with the rings and restrained from linear movement by the ring. 
   
   
       32 . The form, fill and seal packaging machine in accordance with  claim 29  wherein the drive system coupling assembly is a ball screw. 
   
   
       33 . The form, fill and seal packaging machine in accordance with  claim 29  wherein the pump is seal-less. 
   
   
       34 . The form, fill and seal packaging machine in accordance with  claim 29  wherein the piston channel is in alignment with the discharge port during the discharge stroke. 
   
   
       35 . The form, fill and seal packaging machine in accordance with  claim 29  wherein the piston channel is an inlet channel and wherein the piston includes a discharge channel that is in alignment with the discharge port during the discharge stroke.