Abstract: A probe drive system of a precision liquid handler sequentially inserts probe tips of a multiple probe array into a locator well at a known position on a locator bed. The position of each probe tip is determined by driving the probe tip into contact with points on the side wall of the locator well and sensing the contracts. The positions of the probe tips are mapped and checked for skew of the probe array. The probe tip positions are overlaid to determine probe tip scatter. If a probe tip is excessively misaligned, it is inserted into the locator well and driven against the side wall to bend the probe and reduce the misalignment of the probe tip. The center of the probe tip scatter is determined and is used by the probe drive system as a global correction factor. Probe tips with known positions are inserted into spaced apart locator wells to detect skew of the locator bed.

Abstract: A probe drive system of a precision liquid handler sequentially inserts probe tips of a multiple probe array into a locator well at a known position on a locator bed. The position of each probe tip is determined by driving the probe tip into contact with points on the side wall of the locator well and sensing the contracts. The positions of the probe tips are mapped and checked for skew of the probe array. The probe tip positions are overlaid to determine probe tip scatter. If a probe tip is excessively misaligned, it is inserted into the locator well and driven against the side wall to bend the probe and reduce the misalignment of the probe tip. The center of the probe tip scatter is determined and is used by the probe drive system as a global correction factor. Probe tips with known positions are inserted into spaced apart locator wells to detect skew of the locator bed.

Abstract: A probe drive system of a precision liquid handler sequentially inserts probe tips of a multiple probe array into a locator well at a known position on a locator bed. The position of each probe tip is determined by driving the probe tip into contact with points on the side wall of the locator well and sensing the contracts. The positions of the probe tips are mapped and checked for skew of the probe array. The probe tip positions are overlaid to determine probe tip scatter. If a probe tip is excessively misaligned, it is inserted into the locator well and driven against the side wall to bend the probe and reduce the misalignment of the probe tip. The center of the probe tip scatter is determined and is used by the probe drive system as a global correction factor. Probe tips with known positions are inserted into spaced apart locator wells to detect skew of the locator bed.

Abstract: A probe drive system of a precision liquid handler sequentially inserts probe tips of a multiple probe array into a locator well at a known position on a locator bed. The position of each probe tip is determined by driving the probe tip into contact with points on the side wall of the locator well and sensing the contracts. The positions of the probe tips are mapped and checked for skew of the probe array. The probe tip positions are overlaid to determine probe tip scatter. If a probe tip is excessively misaligned, it is inserted into the locator well and driven against the side wall to bend the probe and reduce the misalignment of the probe tip. The center of the probe tip scatter is determined and is used by the probe drive system as a global correction factor. Probe tips with known positions are inserted into spaced apart locator wells to detect skew of the locator bed.

Abstract: A probe drive system of a precision liquid handler sequentially inserts probe tips of a multiple probe array into a locator well at a known position on a locator bed. The position of each probe tip is determined by driving the probe tip into contact with points on the side wall of the locator well and sensing the contracts. The positions of the probe tips are mapped and checked for skew of the probe array. The probe tip positions are overlaid to determine probe tip scatter. If a probe tip is excessively misaligned, it is inserted into the locator well and driven against the side wall to bend the probe and reduce the misalignment of the probe tip. The center of the probe tip scatter is determined and is used by the probe drive system as a global correction factor. Probe tips with known positions are inserted into spaced apart locator wells to detect skew of the locator bed.

Abstract: A probe drive system of a precision liquid handler sequentially inserts probe tips of a multiple probe array into a locator well at a known position on a locator bed. The position of each probe tip is determined by driving the probe tip into contact with points on the side wall of the locator well and sensing the contracts. The positions of the probe tips are mapped and checked for skew of the probe array. The probe tip positions are overlaid to determine probe tip scatter. If a probe tip is excessively misaligned, it is inserted into the locator well and driven against the side wall to bend the probe and reduce the misalignment of the probe tip. The center of the probe tip scatter is determined and is used by the probe drive system as a global correction factor. Probe tips with known positions are inserted into spaced apart locator wells to detect skew of the locator bed.

Abstract: A pipette for transferring liquid samples includes a body having a handle and a base. A piston assembly is axially movable in the body. A movable lower stop is placed in the path of the piston assembly to stop the piston to limit the length of an intake stroke and is withdrawn from the path to permit axial overtravel during a discharge stroke. The lower stop is positively controlled by a manually operated mechanism including a stop control push button at the top of the handle in front of a piston push button. A mechanism for ejecting a tip from the base includes a lever at the top of the handle providing a mechanical advantage when pressed at either end. In an alternate embodiment, a dual spring overtravel arrangement is used, with the piston return spring telescoped within the overtravel spring.

Abstract: A liquid handling apparatus capable of being used as a fraction collector, sampler, dispenser, diluter or the like utilizes a microprocessor and three stepping motors to move a liquid handling tube suitable for dispensing, sampling or the like in two horizontal directions and in a vertical direction with respect to an array of test tubes or similar containers. The apparatus is capable of operating in several modes of dispensing and withdrawal operations, including modes based on the number of drops dispensed or the time spent over each container. The pattern of the movement of the liquid handling tube or dispensing head is selectable to suit the mode of operation of the liquid handling apparatus as well as the type of container and the number of containers being used at a particular time.

Abstract: A precision-delivery and precision-pressure piston pump is actuated by a cam controlled by a finestep stepping motor. The initial delivery pressure is precisely regulated by fixing the commencement of the delivery stroke at the cam with the aid of the stepping motor, as well as the time required for this delivery. Delivery is also regulated very precisely, for example in a ratio of 1 to 1000 by controlling the delivery stroke with the aid of the stepping motor. The pump is of use in particular in high-pressure liquid-phase chromatography.

Abstract: A fraction collector wherein a head is aligned in sequence with individual containers of an array of containers so that fractions or samples may be deposited into the containers from a delivery tube supported by the head. A table surface slidingly supports a number of racks holding rows of containers. The racks are releasably attached to spaced points along a chain moved by a chain drive motor around a closed loop above the table surface. The head is supported above the path of the racks and is moved across the racks and along the rows by a head drive motor. A control circuit controls the chain and head drive motors to advance the chain in increments to position successive rows beneath the head, and moves the head in increments along the container rows to position the head above individual containers.