DESC:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)

COMPLETE SPECIFICATION

(See Section 10; Rule 13)

TITLE

Electronic Filler

APPLICANT
MICROLIT, an Indian Company of
Kursi Road, 629, Pakramau, Lucknow, U.P.-223026, India

AADHAR JAIN, an Indian citizen, of
A-22, Aliganj, Lucknow,U.P.-223024, India

ATUL JAIN, an Indian citizen, of
A-22, Aliganj, Lucknow,U.P.-223024, India

The following specification particularly describes the invention and the manner in which it is to be performed

Electronic Filler
FIELD OF INVENTION

The present invention relates to Electronic Filler or Controller or Pipette Gun with AutoStop technology. More particularly, the present invention discloses electronic filler for pipettes including a wired attachment that enables the user to fill plastic or glass serological pipettes up to any specific volume that they desire.

BACKGROUND ART

Typically, pipettes have a means to set a desired dispensing volume by adjusting a manual setting in the handle. Pipette such as micro-pipette may be spring-loaded and operated using manual power or they may be equipped with an electronic controller and an electrical motor that actuates fluid loading and dispensing. While using a pipette dispenser during the performance of various tasks, a technician repetitively raises and lowers the pipette dispenser with his arm.
The pipettes have a few limitations as it is used to dispense the liquids in microliters and can go up to a maximum of 10000 microliters. Also, depending on the length of the pipette, the height of the technician and the task to be performed over time, the range of motion required by the technician's arm may be great enough to cause discomfort or injury. Pipetting requires repetitive movement which with time may lead to musculoskeletal disorders or MSDs. Several injuries among laboratory workers are CTS or carpal tunnel syndrome, tension neck syndrome, epicondylitis (tennis elbow), tarsal tunnel syndrome, and more. The poor ergonomics of the pipettes, more plunger force, more tip ejection force, or long duration of pipetting contribute to these injuries.

To minimize the limitations of micropipettes, bottle top dispensers were introduced which helped the transfer of liquid up to 100 milliliters from the mouth of the large containers and reagent bottles. The dispensers helped to achieve better reproducibility and ease to work with aggressive reagents, fuming liquids or acids, and sterile liquids. Despite having the advantage over the pipette, the dispensers have limitations. These can only be used to transfer volumes from bottles. Before operating the dispensers, one has to purge them to remove the air bubble from the liquid column. This often leads to loss of reagent (dispensers without recirculation valve) and sometimes causes injury due to splash of the reagent. Furthermore, mounting and dismounting the dispenser can be tricky and may lead to accidents.

Serological or volumetric pipettes are the traditional and convenient mode of liquid transfer in milliliters from reservoirs with either small diameter or long neck, by minimizing the chances of cross contamination. These can be disposable or autoclavable. To draw liquid into a serological pipette, traditionally mouth pipetting was preferred, where the liquid was being drawn using the suction created by mouth. This technique has been banned worldwide due to the serious health risks associated with this. To overcome this, pipette controllers were introduced. The simplest type of pipette controller is the bulb (with no precise dispensing controls) and rubber bulb (with triple valve) which controls air evacuation, liquid uptake, and dispensing.

To make the pipetting easier, manual pumps were introduced. They consist of an exhaust valve (to dispense the liquid), wheel control (to aspirate the volume), and a plunger (to expel the residual liquid). However, to achieve even better precision, electronic pumps were introduced. The electronic pipette filler made the pipetting faster and more accurate with desirable precision.

The electronic pipette filler comprises a collet (to hold the pipette), a hydrophobic filter, separate buttons for aspirating and dispensing, motor controlled speed (with different speeds).

In a prior art by Kenney in U.S. Pat. No. 4,624,147, discloses a pipet gun for drawing liquid into and expelling it from a pipet comprises a housing which includes a hand grip portion and a barrel portion with a pipet-supporting portion connected to the barrel portion, conduits in the housing adapted to connect an air pressure source and a vacuum source to the pipet-supporting portion, valves carried by the hand grip portion in operative engagement with the conduit and operable to selectively establish, and cut off, communication between the pipet supporting portion, air pressure source, and vacuum source. The valves include a molded plastic valve body with a molded plastic back portion connected to a molded plastic front portion with a gasket positioned there between, and the necessity of precision drilling of long bores is eliminated. The pipette gun is operated by depressing one of the two finger-operated triggers to draw fluid into the pipette or expel fluid from the pipette

In another prior art, an US specification US20040074318A1 discloses Foot operated pipette dispenser which includes a pipette dispenser unit having a handheld pipette dispenser having a pipette connector and a handle, a source of positive and negative air pressure in fluid connection with said pipette connector, and a foot-operated controller for regulating the flow of air between said air pressure source and said pipette connector. A method of metering fluid through a pipette by connecting the pipette to the pipette dispenser, holding the dispenser with one hand, and controlling fluid flow through the pipette by operating the controller with at least one foot.

In yet another prior art, an US specification US 7,396,512 B2 discloses automatic precision non-contact open-loop fluid dispensing system including an electronic, hand held fluid dispensing system for use with a laboratory pipette, comprising: a housing capable of being held in one hand; a coupler disposed at least partially within said housing, said coupler being adapted to be removably connected to said pipette; a source of pressure and/or vacuum; a valve pneumatically coupled between said source and said coupler; at least one pressure transducer pneumatically coupled to said coupler, said pressure transducer generating at least one output; and an electronic controller electrically coupled to control at least said valve and also electrically coupled to said pressure transducer, said electronic controller operating in an open-loop mode to control said valve in accordance with a valve control timing parameter derived from said pressure transducer output and a stored quantity parameter relating to a desired quantity of fluid to be dispensed, said valve control timing parameter controlling said valve so that said system automatically, repetitively dispenses Substantially a predetermined quantity of fluid from said pipette.

To fill plastic or glass pipettes up to a specific volume using an electronic pipette filler / gun, users usually use the following method:

GRAVITY DISPENSE
a. Aspirate more than the required liquid
b. Dispense excessive liquid gently until the liquid meniscus aligns with the required mark on the serological pipette
c. Examples (i). Corning Ultra Pipette Controller
(ii). Brand Accuject
(iii). Eppendorf EasyPet

These methods have the following disadvantages:

a) Users have to use their eyesight to match the meniscus of the liquid with the marking on the serological pipette. This leads to human errors and inaccurate liquid dispensing which may hurt the integrity of the experiment
b) Users have to iterate multiple times to achieve exact volume. This is time consuming and frustrating and also leads to quicker discharge of the electronic device.

The shortcomings of conventional techniques mentioned above are not intended to be exhaustive but, rather, are among many that tend to impair the effectiveness of previously known techniques concerning fluid handling. Other noteworthy problems also exist; however, those mentioned here are sufficient to demonstrate that a significant need exists for the techniques described herein.

SUMMARY OF INVENTION

This invention enables lab scientists and technicians to fill serological pipettes up to any desired volume and dispense that accurate amount of liquid for their experiments in an accurate and time-efficient manner by using a wireless attachment to a programmed Electronic Filler or Controller or Pipette Gun. The attachment (Refer to image 1) houses 2 capacitive proximity sensors to detect the position of the aspirated liquid. The lower sensor acts as the first detection point to slow down the speed of aspiration to accurately stop aspiration at the level of the upper sensor. This configuration enables precise stopping of the aspirated liquid at a desired volume.

The primary application of any electronic filler/controller is to enable lab users to precisely fill a serological pipette to a certain specific volume and dispense that aspirated volume of liquid into a container for their experiments. However, pipette controllers in the market do not provide any direct mechanism for the lab user to precisely aspirate and dispense a required volume. The methods employed by lab users to achieve this are inaccurate and time-consuming. Users have to either:

a) Manipulate the speed controller of the pipette filler to precisely fill gently up to the desired volume
b) Fill more than the required volume and dispense slowly (using gravity) to achieve the desired volume

Therefore such as herein described there is provided an auto-stop electronic filler, for dispensing fluid, comprising at least two non-contact liquid level sensor disposed on a pipette configured to detect the presence of liquid; a control apparatus, operably connected with the said level sensor which comprises a data processor capable to execute a control program for controlling at least one electronically controllable function of the said electronic filler using input data, an user interface device for receiving a user input, the user interface device comprising a data input device for providing programmable level and flow data of the said filler and for providing at least flow sequence, which contains subsequently measured real time data, a data memory for storing the at least one flow sequence, and an evaluation device configured to determine the input data in dependence on the evaluation of the flow sequence.

In another embodiment there is also provided a method for operating an auto-stop electronic filler, for dispensing fluid according to any one of claim 1 to 8, comprising the steps of receiving user input and thereby physically regulating the position of the vertically spaced combination of two capacitive non-contact liquid level sensors and executing a control program for controlling at least one electronically controllable function of the said electronic filler using input data and flow data of the pump and the aspiring liquid; storing the at least one flow sequence in a flow data memory; determine the input data in dependence on the evaluation of the at least flow sequence, and controlling at least one electronically controllable function of the said electronic filler using the input data and real time flow data.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Fig 1 illustrates electronic filler with auto-stop feature in accordance with the present invention;

Fig 2 illustrates the image of a prototype electronic filler in accordance with the present invention.

DETAILED DESCRIPTION

The invention is a wireless attachment to a programmed Electronic Filler / Controller that enables the laboratory user to indicate the precise volume on the serological pipette that he/she would like to aspirate/fill to and then dispense that accurate volume of liquid for their experiments.

The user may position the attachment housing at the exact point on the serological pipette till where he/she would like the liquid to be aspirated. The attachment houses a combination of 2 capacitive Non-contact liquid level sensors to detect the presence of liquid. The lower sensor acts as the first detection point to signal to the firmware on the IC to slow down the speed of aspiration (to avoid overshooting of liquid past the selected volume). When the upper sensor detects the presence of liquid, it signals to the IC to stop the pump from aspirating any more liquid thereby stopping the aspirated liquid only up to the desired level. This sensor combination enables the user to aspirate the liquid to a precise level WITHOUT any hit-and-trial methods or any human intervention, saving time and introducing high accuracy to the aspiration process.

The working principle employed to detect the presence of the liquid is based on capacitance variation. When there is no liquid approaching the sensor, there will be some static capacitance to ground on the sensor due to the presence of distributed capacitance. When the liquid level rises slowly to approach the sensor, the liquid parasitic capacitor will be coupled to the static capacitance so that the final capacitance value will increase. A regular flow of energy is established by connecting the sensor electrodes to an alternating current measurement circuit. The more energy flows to the electrodes, the greater the capacitance, meaning more liquid between the electrodes. The change in voltage is due to the presence or absence of medium between two leads of capacitive probes. Now, the changed capacitance signal will be input to the control IC in the pipette controller device for signal conversion, by which to transform the changed capacitance value into the variation of a certain electric signal. Then the degree of the variation can be detected and determined through specific algorithms. When the variation exceeds a threshold value, it means the liquid level has reached the sensing point. The experimental range of sensing is found to be between 0.5 V to 3.3 V DC voltage.

There is provided a control apparatus operably connected with the said level sensor which comprises a data processor capable to execute a control program for controlling at least one electronically controllable function of the said electronic filler using input data. Also provided is an user interface device for receiving a user input, the user interface device comprising a data input device for providing programmable level and flow data of the said filler and for providing at least flow sequence, which contains subsequently measured real-time data. A data memory for storing the at least one flow sequence, and said evaluation device configured to determine the input data in dependence on the evaluation of the flow sequence.

During the filling operation, when the liquid has reached sensing point (the top liquid level sensor) and the control apparatus including a data processor has detected the liquid, it will command the pump to stop operating and the filling valve to close. This will result in the liquid to be stationary at the sensing point due to the vacuum created by the valves in the connecting tubes. The data processor is configured to execute a control program for controlling at least one electronically controllable function of the said electronic filler using input data vide an user interface. The user may achieve the desired amount of reagent liquid in the serological pipette. If the user further tries to fill the pipette, the filling function will not operate and the display will indicate to the user that the sensing point has been achieved. Now, the user may change the sensing point by disengaging the sensor attachment and placing it a different point on the serological pipette. In this scenario, the user may further fill the serological pipette up to the new sensing point.

There is also provided a user interface device (mobile / keyboard) for receiving a user input. The said user interface device includes a data input device for providing programmable level and flow data of the said liquid reagent and for providing at least flow sequence, which contains subsequently measured realtime data. A data memory is provided for storing the at least one flow sequence, and an evaluation device configured to determine the input data in dependence on the evaluation of the said flow sequence.

Once the sensing point is achieved and the filling function is deactivated by the control apparatus, the user may dispense the aspirated liquid in the required container. To achieve this, the user may press the dispense plunger and the control apparatus may command the pump and the dispense valve to activate. The user may dispense specific programmed / all the aspirated liquid, thus achieving the accurate transfer of the desired volume of the reagent. The user may also set the capacity of the serological pipette in use to optimize the speed of aspiration and dispense of the reagent.

Inventive step

1. Wired attachment to an Electronic Pipette Controller to detect liquid level during aspiration
2. Dual capacitive sensor combination to stop liquid aspiration at a desired point
3. Firmware on the microprocessor to take feedback from capacitive sensors and control pump speed

Various aspiration speeds were tested with AutoStop mechanism for different pipette capacities. After thorough experimentation, the following speeds were found to be optimal to work with AutoStop mechanism:

Pipette capacity Max Speed
1ml 0.3 ml / sec
2ml 0.6 ml / sec
5ml 1.5 ml / sec
10ml 3ml / sec
25ml 8ml / sec
50ml 8ml / sec
100ml 8ml / sec

Many modifications may readily be contemplated by those skilled in the art to which the invention relates. Many further modifications may readily be contemplated. The description set out above is particularly applicable to high-rate clarification applications. However, in conventional clarification where the upstream or downstream processes herein described are not used, the teachings according to the invention may have considerable merit and are also applicable. The specific embodiments described, therefore, should be taken as illustrative of the invention only and not as limiting its scope as defined herein
,CLAIMS:We Claim:

1. An auto-stop electronic filler, for dispensing fluid, comprising

at least two non-contact liquid level sensor disposed on a pipette configured to detect the presence of liquid;
a control apparatus, operably connected with the said level sensor which comprises a data processor capable to execute a control program for controlling at least one electronically controllable function of the said electronic filler using input data,
an user interface device for receiving a user input, the user interface device comprising a data input device for providing programmable level and flow data of the said filler and for providing at least flow sequence, which contains subsequently measured realtime data,
a data memory for storing the at least one flow sequence, and
an evaluation device configured to determine the input data in dependence on the evaluation of the flow sequence.

2. The auto-stop electronic filler as claimed in claim 1, wherein the position for said liquid level sensors on said serological pipette is carried out vide attachment housing at the exact point where the liquid needs to be aspirated.

3. The auto-stop electronic filler as claimed in claim 2, wherein the said attachment houses vertically positioned combination of two capacitive non-contact liquid level sensors to detect the presence of liquid.

4. The auto-stop electronic filler as claimed in claim 3, wherein the lower sensor acts as the first detection point to signal to the said control apparatus to slow down the speed of aspiration in order to avoid overshooting of liquid past the selected input volume.

5. The auto-stop electronic filler as claimed in claim 1, wherein under condition that the upper sensor detects the presence of liquid, it signals to said control apparatus to stop the pump from aspirating any more liquid thereby stopping the aspirated liquid only up to the desired level.

6. The auto-stop electronic filler as claimed in claim 3, wherein the said capacitive non-contact liquid level sensors is configured to detect the presence of the liquid is based on capacitance variation; and
under condition that when there is no liquid approaching the sensor, there will be some static capacitance to ground on the sensor due to the presence of distributed capacitance.

7. The auto-stop electronic filler as claimed in claim 1, wherein under condition of aspiration when the liquid level rises to approach the said level sensor, the liquid parasitic capacitor is coupled to the static capacitance so that the final capacitance value gets increased.
8. The auto-stop electronic filler as claimed in claim 1, wherein a regular flow of energy is established by connecting the said liquid sensor electrodes to an alternating current measurement circuit of said control apparatus.

9. A method for operating an auto-stop electronic filler, for dispensing fluid according to any one of claim 1 to 8, comprising the steps of
receiving user input and thereby physically regulating the position of the vertically spaced combination of two capacitive non-contact liquid level sensors and executing a control program for controlling at least one electronically controllable function of the said electronic filler using input data and flow data of the pump and the aspiring liquid;
storing the at least one flow sequence in a flow data memory,
determine the input data in dependence on the evaluation of the at least flow sequence, and
controlling at least one electronically controllable function of the said electronic filler using the input data and real time flow data.

10. The auto-stop electronic filler as claimed in claim 1, wherein said capacitive liquid level sensor combination is configured to stop liquid aspiration at a desired point and the said control apparatus is configured to take feedback from said capacitive sensors and control pump speed.