Pressure regulated electric pump

A pump for delivering pumped liquid at a substantially constant pressure of pumped liquid despite changes in volume flow rate of pumped liquid, the pump comprising:

• a motor having a rotary output;
• a converter between the motor rotary output and the pump, wherein the converter converts the motor rotary output to a reciprocating output that reciprocates the pump;
• a pressure sensor which senses the pressure of pumped liquid;
• and,
• a controller responsive to the pressure sensor which controls the direction and speed of rotation of the motor rotary output in accordance with the sensed pressure of pumped liquid to maintain a substantially constant pressure of pumped liquid.

A pressure regulated electric pump for delivering at least a minimum volume flow rate of pumped liquid, comprising:

• a positive displacement double acting reciprocating pump having an outlet for delivering pumped liquid and an inlet for connection to a supply of liquid;
• a sensor, the sensor sensing the pressure of pumped liquid;
• a motor which produces an output energy and includes a controller responsive to the sensor;
• a planetary roller screw assembly having a roller screw and a roller screw nut, the roller screw nut being reciprocated by and along the roller screw in a direction and at a speed in accordance with the direction and speed of rotation of the roller screw, wherein the roller screw nut is coupled to the pump to reciprocate the pump conjointly with the roller screw nut;
• and,
• wherein the output energy of the motor is responsive to the sensor and rotates the roller screw alternately in opposite directions at speeds of rotation in accordance with the sensed pressure of pumped liquid to reciprocate the pump through pumping strokes at rates that maintain a substantially constant pressure of pumped liquid despite variations in the volume flow rate of pumped liquid.

A pump for delivering at least a minimum volume flow rate of pumped liquid, the pump comprising:

• an outlet for delivering pumped liquid and an inlet for connection to a supply of liquid;
• a controller connected to a sensor which senses the pressure of pumped liquid;
• a motor connected to the controller and responsive to the sensor;
• a planetary roller screw assembly having a roller screw and a roller screw nut, the roller screw nut being reciprocated by and along the roller screw in a direction and at a speed in accordance with the direction and speed of rotation of the roller screw;
• and,
• wherein the motor is responsive to the sensor such that the roller screw alternately rotated in opposite directions and at speeds of rotation in accordance with the sensed pressure of pumped liquid to reciprocate the pump through pumping strokes at rates that maintain a substantially constant pressure of pumped liquid despite variations in the volume flow rate of pumped liquid.