Pump and fluid displacer for a pump

Abstract

An electrically operated displacement pump includes an electric motor having a stator and a rotor. The rotor is connected to the fluid displacer to drive axial reciprocation of the fluid displacer. A controller controls operation of the motor based on an operating state of the motor to control pumping by the displacement pump. The controller is configured to operate the pump in a priming mode. during priming of the pump, and a pumping mode, during pumping of process fluid. The controller causes the fluid displacer to move differently in the priming mode than in the pumping mode.

1 . A pump for pumping a fluid, the pump comprising:
 a first fluid chamber;   a first inlet check valve and a first outlet check valve positioned, respectively, upstream and downstream of the first fluid chamber and which regulate flow into and out of the first fluid chamber;   an electric motor comprising a stator and a rotor, the rotor configured to generate a rotational output;   a drive that converts the rotational output from the electric motor into a linear reciprocating motion;   a first fluid displacer configured to be linearly reciprocated at least partially within the first fluid chamber by the drive to pump the fluid, wherein the first fluid displacer is reciprocated through a continuous series of pump cycles, each pump cycle comprising a pumping stroke phase, a suction stroke phase, and a changeover phase that occurs in each transition between the pumping stroke phase and the suction stroke phase in which the first fluid displacer reverses direction; and   a controller configured to regulate energy delivery to the electric motor in a priming mode during which the pump is primed and in a pumping mode, and wherein the controller regulates the energy delivery in the priming mode such that the rotor rotates to cause the first fluid displacer to move differently through the changeover phase in the priming mode than through the changeover phase in the pumping mode.   
     
     
         2 . The pump of  claim 1 , wherein the controller is configured to regulate the energy delivery to the electric motor such that the rotor rotates to cause the first fluid displacer to pause in the changeover phase in the priming mode to allow one or both of the first inlet check valve and the first outlet check valve to close. 
     
     
         3 . The pump of  claim 2 , wherein the pause occurs at a point of reversing direction such that the first fluid displacer moves in a first direction along the axis, stops in place for a period of time, then moves in a second direction along the axis. 
     
     
         4 . The pump of  claim 2 , wherein the controller energizes the electric motor during the pause to hold the position of the rotor so that the first fluid displacer can resist moving due to back pressure in the first fluid chamber. 
     
     
         5 . The pump of  claim 1 , wherein the controller is configured to cause the motor to drive the fluid displacer to a first constant speed during one of the pumping stroke phase and the suction stroke phase when operating the pump in the priming mode, and wherein the controller is configured to cause the motor to drive the first fluid displacer to a second constant speed during the one of the pumping stroke phase and the suction stroke phase when operating the pump in the pumping mode, and wherein the first constant speed differs from the second constant speed. 
     
     
         6 .- 9 . (canceled) 
     
     
         10 . The pump of  claim 1 , wherein the controller is configured to energize the electric motor to displace the first fluid displacer through one of the pumping stroke phase and the suction stroke phase based on a first speed setpoint while in the priming mode. 
     
     
         11 . The pump of  claim 10 , wherein the controller is configured to energize the electric motor to displace the first fluid displacer through the one of the pumping stroke phase and the suction stroke phase based on a second speed setpoint in the pumping mode, the second speed setpoint differing from the first speed setpoint. 
     
     
         12 . (canceled) 
     
     
         13 . The pump of  claim 1 , wherein the controller is configured to regulate the energy delivery to the electric motor such that the rotor rotates to cause the first fluid displacer to, in the changeover phase during the priming mode, one or both of pause and move slower as compared to the changeover phase during the pumping mode. 
     
     
         14 . The pump of  claim 1 , wherein the controller is configured to regulate the energy delivery to the electric motor such that the rotor rotates to cause the first fluid displacer to move slower in the pumping and suction phases during the pumping mode as compared to when the first fluid displacer moves in the pumping and suction phases during the priming mode. 
     
     
         15 . The pump of  claim 1 , wherein the controller is configured to exit the priming mode based on a sensed condition, and wherein the sensed condition is an increase in current draw by the electric motor indicating pumping against the fluid under pressure. 
     
     
         16 .- 23 . (canceled) 
     
     
         24 . The pump of  claim 1 , wherein the controller causes the first fluid displacer to move such that in the changeover phase while in the priming mode, the first fluid displacer at least one of pauses and moves slower as compared to movement of the fluid displacer during the changeover phase while in the pumping mode. 
     
     
         25 . The pump of  claim 1 , wherein the changeover phase occurs from a beginning of deceleration in a first axial direction along the axis to a beginning of acceleration in a second axial direction along the axis, the second axial direction opposite the first axial direction. 
     
     
         26 .- 29 . (canceled) 
     
     
         30 . The pump of  claim 1 , wherein the controller is configured to regulate the energy delivery to the electric motor such that the rotor rotates to cause the first fluid displacer to move at a first speed in the changeover phase as compared to each of the pumping stroke phase and the suction stroke phase, wherein the first speed is slower than a maximum speed that the electric motor could cause the first fluid displacer to move at during the changeover phase without causing an internal collision within the pump. 
     
     
         31 . The pump of  claim 1 , wherein the controller is configured to regulate a stroke length of the first fluid displacer during the priming mode and during the pumping mode such that the first fluid displacer has a first stroke length during the priming mode and the fluid displacer has a second stroke length different from the first stroke length during the pumping mode. 
     
     
         32 . (canceled) 
     
     
         33 . (canceled) 
     
     
         34 . The pump of  claim 1 , wherein the controller is configured to control displacement of the first fluid displacer such that the first fluid chamber has a first compression ratio with the pump in the prime mode and a second compression ratio with the pump in the pumping mode, the first compression ratio differing from the second compression ratio. 
     
     
         35 . (canceled) 
     
     
         36 . The pump of  claim 1 , wherein the controller is configured to regulate the energy delivery to the electric motor such that a cycle lag occurs between the pump cycle of the first fluid displacer in the priming mode and the pump cycle of the first fluid displacer in the pumping mode. 
     
     
         37 . (canceled) 
     
     
         38 . (canceled) 
     
     
         39 . The pump of  claim 1 , further comprising a second fluid displacer that is driven in synchrony with the first fluid displacer by the drive, the second fluid displacer linearly reciprocated at least partially within a second fluid chamber through a continuous series of second pump cycles, each second pump cycle comprising a second pumping stroke phase, a second suction stroke phase, and a second changeover phase that occurs in each transition between the second pumping stroke phase and the second suction stroke phase in which the second fluid displacer reverses direction. 
     
     
         40 . The pump of  claim 1 , wherein the controller is configured to regulate the energy delivery to the electric motor in the changeover phase of the priming mode such that the controller energizes the motor to urge the rotor in a first direction with a first driving energy profile and then urges the rotor to spin in a second direction opposite the first direction by delivering a second driving energy profile while the rotor spins in the first direction until the rotor nears stoppage or stops, in which state the controller regulates energy delivery to the electric motor such that no motive energy is delivered to the motor or a third energy profile is delivered to hold the rotor still, and then the controller resumes delivery of the second driving energy profile to accelerate the rotor to spin in the second direction. 
     
     
         41 . A pump for pumping a fluid, the pump comprising:
 a first fluid chamber;   a first inlet check valve and a first outlet check valve positioned, respectively, upstream and downstream of the first fluid chamber and which regulate flow into and out of the first fluid chamber;   an electric motor comprising a stator and a rotor, the rotor configured to generate a rotational output;   a drive that converts the rotational output from the electric motor into a linear reciprocating motion;   a first fluid displacer configured to be linearly reciprocated at least partially within the first fluid chamber by the drive to pump the fluid, wherein the first fluid displacer is reciprocated through a continuous series of pump cycles, each pump cycle comprising a pumping stroke phase, a suction stroke phase, and a changeover phase that occurs in each transition between the pumping stroke phase and the suction stroke phase in which the first fluid displacer reverses direction; and   a controller configured to regulate energy delivery to the electric motor in a priming mode during which the pump is primed and in a pumping mode, wherein the controller regulates the energy delivery based on a target priming speed of the first fluid displacer in the priming mode and based on a target pumping speed of the first fluid displacer in the pumping mode, the target priming speed greater than the target pumping speed.   
     
     
         42 .- 70 . (canceled) 
     
     
         71 . A pump for pumping a fluid, the pump comprising:
 a first fluid chamber;   a first inlet check valve and a first outlet check valve positioned, respectively, upstream and downstream of the first fluid chamber and which regulate flow into and out of the first fluid chamber;   an electric motor comprising a stator and a rotor, the rotor configured to generate a rotational output;   a drive that converts the rotational output from the electric motor into a linear reciprocating motion;   a first fluid displacer configured to be linearly reciprocated along an axis and at least partially within the first fluid chamber by the drive to pump the fluid, wherein the first fluid displacer is reciprocated through a continuous series of pump cycles, each pump cycle comprising a first stroke in a first direction along the axis, a second stroke in a second direction along the axis, a first changeover in which the first fluid displacer reverses direction from the first stroke to the second stroke, and a second changeover in which the first fluid displacer reverses direction from the second stroke to the first stroke; and   a controller configured to regulate energy delivery to the electric motor in a priming mode during which the pump is primed and in a pumping mode, wherein the controller regulates the energy delivery such that the first fluid displacer moves a first distance through the first stroke in the priming mode and the fluid displacer moves a second distance through the first stroke in the pumping mode, the first distance greater than the second distance.   
     
     
         72 .- 98 . (canceled)