EP0261023B1 - Identification method for a laboratory instrument, and pipette identified accordingly by colours - Google Patents

Abstract

The invention relates to a method for identifying a laboratory instrument (1) comprising at least one transparent tube (2) enabling the user to identify immediately and unmistakably at least one of its characteristics - in particular its maximum volume - , in which method identifying means (6) are inserted into the interior (7) of the tube (2) in such a way that they will be visible from the outside in all conditions. <IMAGE>

Description

The invention relates to a method for characterizing a laboratory pipette allowing a user to identify immediately and without possible error at least the maximum or nominal volume by coloring.

It is crucial for a laboratory instrument to be able to be identified quickly and unambiguously as to its main characteristics, even when mixed with other instruments and whatever its position.

This problem arises in particular for laboratory pipettes, in particular disposable disposable pipettes, for which the user must be able to identify the maximum volume at first glance immediately and without possible error. Indeed, the pipettes of different volumes are relatively little different from each other and can be confused as soon as the conditions of use are not perfect (disorder, many pipettes, rapid and / or numerous manipulations ...).

To solve this problem, the first solution consisted in writing on the pipette, above the graduations, the volume of the pipette with the various other information and characteristics (temperatures of use, tolerances ...). This solution is not satisfactory since it is necessary to read the characteristic carefully. Thus, it is not possible to instantly choose a pipette of a given volume in the middle of a group of pipettes of various volumes.

To overcome these drawbacks, we thought of characterizing the pipettes by a color code. The pipette then has a colored mark, the color of which is in one-to-one relation with volume. The simple view of the color makes it possible to immediately and unambiguously identify the volume of the pipette.

In a first known embodiment, a longitudinal strip of paint is applied opposite the graduations. The major drawback of this solution is that the identification of the volume is only possible if the pipette is in a position such that the strip of paint is oriented towards the user. Otherwise, the graduations hide the paint strip. In addition, when this strip of paint is affixed on the periphery of the instrument to be seen in any position (US Pat. No. 3,406,573), it may hinder reading and measurement, and may deteriorate as a result of manipulation or of transportation. The affixing of such a strip is, more expensive to achieve.

In a second known embodiment, a colored plastic tip is used to associate the suction end of the pipette with suction. This tip is made of colored injected plastic and is hermetically associated with the pipette, that is to say without leakage at the junction. Advantageously, a protective filter material can be inserted into the nozzle. The disadvantage of this embodiment is that it is too sophisticated and far too expensive. In particular, the hermetic junction of the injected nozzle or tube poses many problems and must be carried out by expensive techniques (for example ultrasonic welding). In addition, you cannot see from the outside the quality of the protective filter material in the nozzle, or even be sure of its presence.

Finally, in many applications, it is necessary to have laboratory instruments that are completely sterile and inert vis-à-vis chemical and / or biological substances. This is the case in particular in the medical or biological field, in serology or immunology or microbiology ... We know (English patent GB 1,567,325) that to satisfy these constraints, it is advantageous to use sterile disposable pipettes comprising in their suction end a cotton or viscose pad forming sterile protection to define the level maximum of the pipette, absorbing the aspirated liquid enough to retain it in the pipette, and preventing the liquid from flowing through the suction end. A disposable pipette is produced in a known manner from extruded synthetic material.

It is also known (English Patent GB 2,486,78) that it is possible to provide projections or grooves in a cork stopper intended for bottles for medical use. However, such teaching does not solve the problems mentioned above.

The invention aims to remedy the above-mentioned drawbacks of known characterization methods and pipettes, and relates to a method for characterizing a pipette which ensures immediate identification at first sight, perfect and without possible error, does not not altering the sterility properties of the instrument, inert with respect to chemical and / or biological substances and which does not increase or even decrease the cost price of the instrument thus characterized. Another object of the invention is to allow the characterization of a pipette in a safe manner, without possible deterioration of this characterization during handling, transport, or bringing the instrument into contact with aggressive external agents. , and without harming the qualities of the instrument (precision, reliability of use, safety ...). The invention also relates to a pipette whose volume is identifiable immediately and without possible error, which can be completely sterile and inert vis-à-vis chemical and / or biological substances, and whose cost price is less than or equal to that of known pipettes.

To do this, the invention relates to a method for characterizing a laboratory pipette comprising at least one transparent tube by colored characterization means allowing the user to identify immediately and without possible error at least the maximum volume or nominal, characterized in that at least one piece of colored material is inserted, the color of which corresponds to said volume inside the suction end of the pipette, so that this piece of colored material is visible from the outside in all circumstances while being sheltered from external aggressions.

You can use as many colored pieces as there are characteristics to identify. The characterization means are inserted in a part of the tube free of graduations and distant from any graduation or inscription.

The invention also provides a laboratory pipette of the type comprising colored characterization means whose color corresponds to the maximum or nominal volume of the pipette, allowing a user to identify immediately and without possible error the maximum or nominal volume of the pipette , characterized in that the characterization means consist of at least one piece of colored material which is inserted into the suction end of the pipette. In the case where a sterile protection must be provided at the suction end, the latter is colored and constitutes the means for characterizing the volume of the pipette.

The invention therefore makes it possible to produce laboratory instruments of very safe use, at very low cost price and perfectly sterile and inert. It will be more advantageously noted that the coloration is all the more effective the support is a fibrous or cellular material and that it is visible through the tube. It will also be noted that the invention allows the coding of several characteristics on the same laboratory instrument in a visible manner from the outside whatever the position of the instrument and protected from external aggressions, and this, so economical and easy, while this was not possible thanks to the prior art.

Other advantages and characteristics will appear on reading the following description referring to the single appended figure which is a schematic elevation view of a pipette according to the invention.

The invention relates to a method for characterizing a laboratory pipette 1 comprising at least one transparent tube 2. Such a pipette 1 makes it possible to withdraw a precise dose of a chemical and / or biological substance, and comprises a graduated tube 2 on at least part of its external surface 3, a sampling end 4 and a suction end 5. The operation of such a pipette 1 is well known in the prior art and will therefore not be detailed. Such a characterization process is applicable to other laboratory instruments, since they comprise at least one transparent tube 2 (columns, test tubes, etc.), and allows the user to identify immediately, at the first look, and without possible error, at least one characteristic, for example the maximum volume, or useful, or nominal, or the conditions of use ...

According to the invention, means 6 for characterization are inserted inside 7 of the tube 2, so that these means 6 are visible from the outside in all circumstances, that is to say whatever the conditions of use of the instrument and its position vis-à-vis the user's gaze.

The characterization means 6 are preferably inserted into a part 8 of the tube 2 free of graduations 9 and distant from any graduation or inscription, so as to be all the more visible through the transparent tube 2 and not to affect the accuracy, reliability or safety of use of the instrument.

Preferably colored characterization means 6 are used which define a color code in one-to-one relation with the values of the characteristic of the instrument 1. Thus, there is an international standard coding by colors the maximum or nominal volumes of current pipettes . This standard specifies for example that the pipettes of 1 ml are characterized by yellow, those of 2 ml by white, those of 5 ml by blue, those of 10 ml by orange ... etc.

In this case and according to the invention, inside 7 of an end 5 of a transparent tube 2 is inserted through which no chemical and / or biological substance must pass, at least one piece 6 of colored material constituting the means of characterization.

According to the instrument 1 and the application which is made of it, one uses to carry out the means 6 of characterization at least a piece 6 of a material which lets pass the gases (case of a pipette), or hermetic and in this In this case, the characterization means 6 can also serve as means for closing the tube 2.

Preferably, at least one piece 6 made of a hydrophobic material is used so as to limit measurement errors, accidents or deterioration of the chemical and / or biological substances if these come into contact with or in the vicinity of the characterization means 6 .

According to the invention, or uses as many colored pieces 6 as there are characteristics to be identified, each piece 6 being of a single color corresponding to a value of a characteristic, the pieces 6 being superimposed on each other. in tube 2.

The dye used to color a piece 6 constituting the characterization means 6 is inert vis-à-vis the chemical and / or biological substances so that the characterization means 6 do not modify the physical or chemical properties of these substances.

Preferably, the dye used is of the light-resistant type, and advantageously to liquids.

The invention also relates to a laboratory pipette 1 of the type comprising characterization means 6 allowing a user to identify immediately and without possible error the maximum or nominal volume of the pipette 1, characterized in that the characterization means 6 consist of at least one piece 6 of colored material, the color of which corresponds to the maximum or nominal volume of the pipette 1, and which is inserted into the suction end 5 of the pipette 1.

The pipette 1 according to the invention is advantageously of the disposable type. In the case where it must include a sterile protection at its suction end 5, this protection is colored and constitutes in itself means 6 for characterizing the volume of the pipette 1.

The pipette 1 shown is made up of two parts: a graduated dosing tube 2 extruded from a single piece, and a buffer 6 of colored material inserted into the suction end 5 which has the function of producing means for characterizing the volume and protection by forming a sterile barrier between the mouth of the user and the substances used in the pipette 1.

According to the invention, the piece 6 of colored material is preferably of fibrous or cellular hydrophobic material, in particular of wood viscose or cellulose or cotton or other. Other synthetic or natural materials may be used as soon as they can be sterile, inert, hydrophobic, easily colored, low cost, and holding by contact in the tube 2.

The dimensions of the colored buffer 6 will be adapted as a function of the diameter of the tube 2 at its suction end 5 so as to be able to be inserted and to be wedged by itself in the end 5 of the tube 2 by simple contact with the walls internal, as is known from the prior art.

The pad 6 of colored material has a length such that its end 11, facing inward 7 of the pipette 1 is distant from the maximum level 12 of the pipette 1, for example, materialized by a double graduation 12. Thus, the fluid taken from the pipette 1 can normally never come into contact with the buffer 6 of colored material.

The sampling end 4 of the pipette 1 is formed in a point. From a certain nominal volume of pipette 1, in particular for pipettes 1 whose nominal volume is greater than or equal to 5 ml, the suction end 5 has a diameter less than the diameter of the graduated part 10 of the tube 2 The internal diameter of this end 5 is advantageously between 2 mm and 8 mm, in particular of the order of 3 to 5 mm. The length of the buffer 6 is less than that of the suction end 5, so that this buffer 6 does not open into the part 10 of the pipette 1 of large diameter.

It has been noted that the fact of coloring a pad of wood or cotton viscose by dyeing reduces the propensity of the pad 6 to fray in the tube 2, which is another advantage of the invention.

The dye used must be resistant to light, and preferably also to washing, although this is not necessary since the substances dosed in the pipette 1 are not supposed to come into contact with the buffer 6.

Tests carried out on wood viscose or hydrophobic cotton pads 6 have shown that substantive direct dyes such as azo derivatives can be used. Blue 106, red 80, according to the COLOR INDEX classification, for example, gave excellent results. These dyes hang perfectly on viscose and cotton.

To manufacture a pipette 1 according to the invention, the tube 2 is extruded continuously which is graduated, then a protective pad 6 previously tinted is inserted into the suction end 5. The assembly is then packaged and then sterilized, for example with ethylene oxide followed by rinsing with air, or even with nuclear radiation.

Claims (13)

1. Process of characterisation of a laboratory pipette (1) comprising at least one transparent tube by means of coloured characterisation means permitting the user to identify, immediately and without the possibility of error, at least the maximum or nominal volume of the said pipette, characterised in that at least one piece (6) of coloured material, the colour of which corresponds to the said volume, is inserted in the interior (7) of the suction end (5) of the pipette in such a way that this piece of coloured material is visible from the outside in all circumstances while being protected from external aggressions.
2. Process according to Claim 1, characterised in that the piece of coloured material is inserted into a part (8) of the tube (2) which is free from graduations (9) and away from any graduation or inscription.
3. Process according to either of Claims 1 and 2, characterised in that at least one piece (6) of a material is used which allows gases to pass through the end (5).
4. Process according to either of Claims 1 and 2, characterised in that at least one piece (6) of a hermetic material is used.
5. Process according to any one of Claims 1 to 4, characterised in that at least one piece (6) of a hydrophobic material is used.
6. Process according to any one of Claims 1 to 5, characterised in that as many coloured pieces (6) as there are characteristics to identify are used, each piece (6) being of a single colour corresponding to a value of a characteristic, the pieces (6) being superposed on one another in the tube (2).
7. Process according to any one of Claims 1 to 6, characterised in that the colouring of a piece (6) of coloured material is chemically and/or biologically inert - in particular is a direct substantive colouring.
8. Process according to any one of Claims 1 to 7, characterised in that the colouring used is of the type which is resistant to light.
9. Laboratory pipette of the type comprising coloured characterisation means (6), the colour of which corresponds to the maximum or nominal value of the pipette (1), the said characterisation means permitting a user to identify, immediately and without the possibility of error, the maximum or nominal volume of the pipette, characterised in that the characterisation means are composed of at least one piece (6) of coloured material which is inserted into the suction end (5) of the pipette (1).
10. Pipette according to Claim 9 comprising a sterile protection at its suction end (5), characterised in that the protection is coloured and constitutes in itself characterisation means (6) of the volume of the pipette (1).
11. Pipette according to either of Claims 9 and 10, characterised in that it is composed of two pieces: a graduated dosage measuring tube (2) extruded in a single piece, and a wad (6) of coloured material inserted into the suction end (5).
12. Pipette according to any one of Claims 9 to 14, characterised in that the piece (6) of coloured material is made of a fibrous or hydrophobic cellular material, in particular viscose, cellulose or cotton.
13. Pipette according to any one of Claims 9 to 12, characterised in that the piece (6) of coloured material is of a length such that its end (11) directed towards the inside of the pipette (1) is far away from the maximum level (12) of the pipette, the fluid withdrawn never normally being able to come into contact with this piece (6) of coloured material.

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