Chemical apparatus and process disinfecting – deodorizing – preser – Analyzer – structured indicator – or manipulative laboratory... – Sample mechanical transport means in or for automated...
Reexamination Certificate
1998-12-04
2001-01-30
Wallenhorst, Maureen M. (Department: 1743)
Chemical apparatus and process disinfecting, deodorizing, preser
Analyzer, structured indicator, or manipulative laboratory...
Sample mechanical transport means in or for automated...
C422S065000, C422S067000, C436S043000, C436S046000, C219S385000, C219S386000, C219S521000
Reexamination Certificate
active
06180061
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a pump mechanism for dispensing small aliquots of a fluid, such as a biological reagent. It may serve as part of an apparatus which dispenses a plurality of reagents to be dispensed in small volumes.
Current methods for dispensing reagents generally use pumps which require the priming of tubing lines leading into and out of a pump. When the pumping is finished, the tubing lines must be flushed before a different reagent can be pumped, lest cross-contamination of reagents occur. Because of the need for priming and clearing tubing lines, such types of pumps are not easily interchangeable.
Pumping systems using a syringe housing (“syringe pumps”) are well known to those in the field. The syringe is first filled with a liquid. The liquid can then be accurately dispensed by applying a precise pressure on the plunger, usually by an electromechanical actuator. The distance that the plunger is depressed directly controls the amount of fluid to be dispensed. Such syringe pumps have two advantages: 1) the absence of tubing lines leading into and out of a pump which must be primed and flushed, and 2) a separation of the wetted components from the electromechanical controlling elements.
Such syringe pumps are useful in situations where repetitive dispensing of precise amounts of liquid are required. A drawback of such syringe pumps is that interchanging syringes on a single electromechanical actuator requires that the actuator mechanism be realigned with the position of the syringe plunger that is being inserted. In circumstances where the syringes need to be changed often in order to change the dispensed reagent, the need for repetitive manual intervention to align the electromechanical actuator with the position of the syringe plunger is a disadvantage. This disadvantage will be more acutely felt in a dispensing instrument with many electromechanical actuators.
SUMMARY OF THE INVENTION
In accordance with an aspect of the present invention, a pump cartridge comprises a reagent reservoir for containing a liquid. The reservoir has a liquid flow outlet at the bottom thereof. A metering chamber is directly connected to the liquid flow outlet of the reagent reservoir. The metering chaber comprises a compressible housing having a noncompressed shape. A one-way inlet valve and a one-way outlet valve are provided at respective ends of the compressible housing and are aligned in the same direction to allow unidirectional flow from the reservoir through the housing. The compressible housing may be compressed for the unidirectional ejection of a volume of liquid from the metering chamber. The compressible housing returns to the noncompressed shape after cessation of compression to draw an additional volume of liquid into the metering chamber.
A cartridge pump in accordance with the present invention may be used as a component of a movable platform containing a plurality of electromechanical actuators. In this manner, any desired liquid reagent contained in any of the cartridges can be dispensed at any location underneath the platform's reach. Alternatively, the present invention includes a rotor containing reagents and a rotor containing slides that rotate on the same axis. A single actuator is located on a station enabling the slides to be accessed by the reagents. At the end of the working session, the cartridges can be easily replaced with different cartridges using the same electromechanical actuators without the need for aligning electromechanical actuators with the cartridges. This aspect increases the versatility of the dispensing instrument as a whole.
In a dispensing assembly, a pump cartridge frame may hold the pump cartridge in a fixed position with respect to an actuator capable of compressing the compressible housing of the pump cartridge. Preferably, the actuator is an electromechanical actuator. The dispensing assembly may be mounted on a moveable platform for dispensing various reagents in various sample cells. In one embodiment, a plurality of electromechanical actuators are positioned adjacent to a plurality of receptacles on the frame into which a plurality of pump cartridges can be fit.
The cartridge may have one or more ridges extending outwardly from its external surface to serve as keys in grooves in a supporting frame. Cartridges may be coded by the circumferential positions of ridges to assure that cartridges containing particular reagents are inserted in appropriate locations in the frame.
According to another aspect of the invention, a dispensing assembly comprises an assembly base and a slide rotor adapted to carry a plurality of slides holding tissue samples. This slide rotor is capable of rotating on the assembly base. Further, a reagent rotor adapted to carry a plurality of different reagents sits above the slide rotor and is also capable of rotating on the assembly base.
In preferred embodiments, slide frames are provided for holding the slides in the slide rotor. The slide frames are radially insertable into the slide rotor. These slide frames themselves comprise a slide frame base adapted to support a plurality of slides and containing resistive heating units for heating each one of these slides. A thermocouple can also be provided to detect the temperature of the slides as heated by the resistive heating units. A slide frame housing is adapted to sealably fit over the slide frame base to create cavities over each of the slides and place each of these slides in fluid isolation from each other.
The reagent rotor carries at least one pump cartridge frame that comprises a plurality of receptacles for receiving a plurality of cartridge pumps. These cartridge pumps comprise a reservoir for containing a reagent, a resilient metering chamber in fluid communication with an outlet of the reservoir and a one way inlet valve and one way outlet valve at each end of the resilient metering chamber.
The dispensing assembly further comprises a dispensing station positioned adjacent to each of the slide rotor and the reagent rotor. This dispensing station comprises an actuator adapted to deform the resilient metering chamber in a cartridge pump so that a volume of reagent contained in that cartridge pump is ejected into a slide underneath the cartridge pump held by the slide rotor. This dispensing station also includes a plurality of pressurized rinse bottles and rinse tubes that extend from the rinse station above the slides held by the slide rotor. As such, they can convey rinsing solutions by the opening of pinch valves to the slides underneath the ends of the rinse tubes. Still further, the dispensing station includes a vacuum bottle and vacuum hose that is extendable into a cavity above the slides on the slide rotor to enable removal of rinse solutions covering the slides.
According to another aspect, the reagent reservoir of the cartridge pumps may contain a plunger above the liquid in the reagent reservoir. The plunger is capable of moving within the reservoir as liquid is drawn out of the reservoir through the liquid flow outlet. Preferably, the plunger has a frictional force against the inner wall of the reservoir which is greater than the gravity pressure of the liquid in the reservoir in order to prevent spontaneous dripping of the liquid out of the outlet valve. Alternatively, the outlet valve in its normally closed position may itself have an opening pressure which is greater than the gravity pressure applied by the liquid in the reservoir. Alternatives to the plunger include a one-way valve at the top of the reservoir, a rolling diaphragm at the top of the reservoir and a small aperture at the top of the reservoir.
To reduce the flow velocity of liquid during ejection, a nozzle with an inner diameter which is greater than the opening diameter of the outlet valve may be positioned below the outlet valve.
To absorb some of the initial force upon impact of the actuator against the tubing, the actuator may be a compressible piston hammer mounted on a piston arm.
The interchangeable pump cartridge of the present i
Bogen Steven A.
Loeffler Herbert H.
CytoLogix Corporation
Hamilton, Brook, Smith & Reynold, P.C.
Wallenhorst Maureen M.
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