Portable automated pipette for accurately pipetting and/or titrating liquids

The combination of:

• a linear actuator for connection to a pipetting displacement assembly having a displacing piston with a first limit of travel after the maximum intake of liquid and a second limit of travel after the discharge of liquid from the displacement assembly;
• a motor for driving the linear actuator;
• and
• a control circuit means for energizing the motor to (1) drive the piston to the second limit of travel and the motor to slip and (2) then to retract the piston a predetermined distance.

A handheld self-contained automated pipette for portable operation, comprising:

• an electrically operated linear actuator in a hand-holdable and portable housing;
• a pipetting displacement assembly having one of various sizes removably attached to and for actuation by the linear actuator and including a displacing piston in a displacement cylinder for drawing liquid into and dispensing liquid from a tip connected to the displacement assembly in fluid communication with the cylinder;
• and
• an operator actuatable control and display means in the portable housing to selectively allow for selecting one of various modes of operation for the pipette, for programming movement of the displacing piston in the displacement cylinder to optimize air interface volume, for neutralizing variations in vacuum pipette effects and for providing an accommodated stroke and readout for improved accuracy while pipetting and/or titrating different ranges of volume with the pipette, the control and display means including
• an operator programmable control circuit for selectively actuating and precisely driving the linear actuator in several different modes of pipette operation,
• a display in circuit with the programmable control circuit and carried by the portable housing for visually displaying the selected operating mode and liquid volume to be handled by the pipette, and
• a keyboard in circuit with the programmable control circuit and carried by the portable housing for actuation by the operator to select the mode of pipette operation and the liquid volume to be handled by the pipette during the selected mode of operation.

A compact electronically programmable handheld self contained automated pipette for portable operation, comprising:

• a linear actuator drive module including
• a motor supported in a hand-holdable housing for the drive module,
• a control circuit within the drive module housing for supplying power to and controlling operation of the motor in selective accordance with preset and/or operator actuated instructions,
• a shaft connected to the motor for moving in precise lengthwise increments in response to operation of the motor,
• a keyboard connected to the control circuit and carried by the drive module housing for actuation by an operator to deliver electronic instructions to the control circuit, and
• a display connected to the control circuit and carried by the drive module housing adjacent the keyboard for selectively displaying operating modes and/or the preset and operator actuated instructions for the pipette;
• and
• a pipette displacement assembly secured to the drive module in line with the shaft and including
• a displacement cylinder,
• a displacing piston within the cylinder,
• means for communicating linear translation of the shaft to the piston when the displacement assembly is secured to the drive module, and
• a displacement chamber within the cylinder having a first end in communication with the piston and having a second end with an aperture in communication with a tip for receiving liquid to be pipetted.