Laboratory microtitration dispensing apparatus

Claim 2

Dispensing apparatus comprising a base, liquid reservoir means comprising a portion of said base, carrier means mounted on said base for horizontal movement between a first nondispensing position at one side of said liquid reservoir means and a second dispensing position in which said carrier means overlies a portion of said liquid reservoir means, liquid receptacle means supported on said carrier means, pickup and dispensing means mounted on said base in operative alignment above said portion of said reservoir means, means for moving said pickup and dispensing means vertically relative to said base, whereby, when said carrier means is in said first position, said pickup and dispensing means may be lowered to a first position to withdraw liquid from said portion of said reservoir means, then raised to permit said carrier means to be placed in said second position, and then lowered to a second position to dispense the withdrawn liquid into said receptacle means.

Claim 3

Dispensing apparatus as in claim 1, said pickup and dispensing means comprising a plurality of dispensing needles and means operative to simultaneously withdraw microquantities of liquid from said reservoir into said needles and then simultaneously dispense the same into said receptacle means.

Claim 4

Dispensing apparatus as in claim 2, said liquid receptacle means comprising a microtitration plate having a plurality of wells corresponding in number to the number of said dispensing needles, means on said carrier means for positioning said microtitration plate to ensure that said needles and wells are operatively aligned when said carrier means is moved to said second position.

Claim 5

Dispensing apparatus as in claim 2, said pickup and dispensing means comprising manifold means having a centered main air passageway intersected by a plurality of side-by-side related angularly directed passageways each of which is intersected by a plurality of generally right angularly related passageways, head means connected to said manifold and having a plurality of apertures aligned with said vertical passageways but separated therefrom by flexible diaphragm means, an actuator assembly mounted in each of said apertures and including piston means normally biased to maintain said flexible diaphragm means out of its respective one of said apertures, means connecting a dispensing needle to each of said actuator assemblies, and means for supplying air to and exhausting air from said manifold passageways whereby the differential pressure on opposite sides of said diaphragm means expands said diaphragm means into each of said plurality of apertures and activates each said actuator assembly to simultaneously pick up from said reservoir means into and thereafter simultaneously dispense from said needles predetermined volumes of liquid.

Claim 6

Dispensing apparatus as in claim 4, said head means apertures each comprising a plurality of cylindrical sections of respectively greater diameter from the bottom to the top of said dispensing head means, each said actuator assembly includes a chuck having a tubular stem extending downwardly through the bottom section of said aperture, an enlarged hollow head portion located within the top section thereof, spring means positioned within an intermediate section for biasing said head portion upwardly into sealing engagement with said diaphragm means, said piston means being slidably mounted within said chuck and comprising a rod within said tubular stem and a piston head of lesser axial length within said enlarged hollow head portion, and spring means mounted between said chuck head end wall and said piston head biasing said piston head into engagement with said diaphragm means, whereby when said diaphragm means is displaced in response to the air pressure in said manifold said piston means is moved to dispense fluid from said needle.

Claim 7

Dispensing apparatus as in claim 4, said air supply means comprising an air pressure source, pressure regulating means connected to said source and regulating the pressure of air supplied to solenoid operated air valve means, conduit means connecting said air valve means to said manifold main passageway, flow restrainer means located in said conduit means and controlling the flow rate of air therethrough, and switch means operative to pass electrical current to said solenoid operated air valve means to open said valve means and pass air through said flow restrainer means to said manifold main passageway.

Claim 8

Dispensing apparatus as in claim 6, said valve means comprising vent means operative when said valve is closed to exhaust said manifold passageways and said conduit means to atmosphere.

Claim 9

Dispensing apparatus as in claim 2, said pickup and dispensing means comprising manifold means, a pipette head unit for supporting said dispensing needles, flexible diaphragm means operatively positioned between said manifold means and pipette head unit, said manifold means having air passage means leading to one side of said diaphragm means, and a pneumatic supply system connected to said air passage means for actuating said diaphragm means to simultaneously pick up predetermined quantities of liquid from said reservoir means into said needles and thereafter simultaneously dispense the quantities of liquid from said needles.

Claim 10

Dispensing apparatus as in claim 1, said liquid reservoir means comprising a trough positioned underneath said pickup and dispensing means, a liquid supply tank remote from and communicating with said trough through a well and connecting channel, outlet means on said tank controlling the flow of liquid therefrom to said well to maintain the liquid level in said trough at a substantially constant level.

Claim 11

Dispensing apparatus as in claim 9, said trough including a plurality of partitions having aligned circular side recesses, the opposing recesses of adjacent partitions defining a plurality of needle pockets which function to eliminate adherent liquid from the external surfaces of said dispensing needles when said needles are raised out of said trough.

Claim 12

Dispensing apparatus as in claim 1, wherein said base comprises a rectangular platelike member having an upstanding support post disposed at the opposite side of said liquid reservoir means and said means for moving said pickup and dispensing means comprises a control gear housing carried by said post in vertically upwardly spaced relation to said platelike member and mounting a vertically movable rack gear carrying at its lower end a bracket fixedly mounting said pickup and dispensing means and pinion gear and shaft means including a handle member for selectively rotating said pinion gear and shaft means in a direction to first drive said rack gear to position said pickup and dispensing means in said first position, then in an opposite direction to its raised position, and finally in said first direction to said second position, said first and second positions being predetermined by dependent stop rods carried by said pickup and dispensing means for end abutting engagement respectively with said portion of said base in said first position and with the top wall of said liquid receptacle means in said second position.