Pipette system

A pipette system with a syringe comprising a syringe flange and a syringe plunger, and with a pipette which in a pipette body comprises an accommodation for the syringe flange and in an accommodation body comprises a plunger accommodation for the syringe plunger, further comprising fastening mechanism for releasably fixing the syringe flange and the syringe plunger to their accommodations, and plunger adjusting device for displacing the accommodation body within the pipette body, the syringe comprising a data carrier with an information about the syringe and/or the condition thereof, and the pipette comprising a sensing device for the information on the data carrier, the syringe flange and the syringe plunger being axially movable into their positions of attachment in the pipette through axial openings of their accommodations, the data carrier being placed into a sensing position with respect to the sensing device and the syringe flange comprising a ring having at least one axially directed sensed area as a data carrier in an axial position.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The object of the invention relates to a pipette system including a syringe 
having a syringe flange adapted to be received in an accommodation 
provided in the pipette body, an accommodation body displaceable within 
the pipette body and having a plunger accommodation for receiving the 
syringe plunger, and sensing means for detecting information provided on a 
data carrier associated with the syringe. 
2. Description of the Prior Art 
Pipette systems of the type referred to at the beginning often are defined 
as repeating or multipipette systems which allow the gradual delivery of a 
liquid from a syringe. Such a repeating system is known from the DE-C2 29 
26 691 which especially is directed to the repeating mechanism of the 
repeating pipette. It also describes how to secure a syringe of the system 
to said repeating pipette. For this purpose, the syringe is provided with 
a syringe flange adapted to be inserted from the side into a substantially 
U-shaped groove being open at the side. An axial pressure spring secures 
the inserted syringe flange to the nut. For the connection of the syringe 
plunger to a plunger adjusting means an insertion element is provided 
which receives an end section of the syringe plunger between two jaws. The 
jaws can be pressed against said syringe plunger by means of a flap-like 
clamping element, the actuating lever of which projects from the body 
through an opening. 
According to this system, the syringe flange besides may comprise a 
profiling upon which a spring-actuated lever of the repeating pipette is 
acting. The lever is connected to the plunger adjusting means and adjusts 
the dosing volume. Thereat the syringe flange is profiled so that in 
dependence on its rotary position in its body accommodation different 
dosage volumes are adjusted. This enables the user to adjust the dosage 
quantity of the syringe by its rotation in the syringe accommodation. For 
the same repeating pipette, however, syringes with different absorption 
capacities are provided. They differ from each other by different cross 
sections of absorption, with the total length being the same. Identical 
profilings of the syringe flange of different syringes, therefore, do not 
allow the dosage quantities to be adjusted coincidently. On the contrary, 
the use of syringes of different capacities makes a conversion necessary. 
As a result of the limited available space the different syringes namely 
cannot be profiled individually. Moreover, the profiling also allows the 
adjustment of discrete dosage quantities only. Any intermediate values or 
values beyond the range of adjustment determined by the profiling cannot 
be achieved. 
Taking all these facts into consideration, it is the object of the 
invention to provide a pipette system which allows an identification of an 
inserted syringe or the condition of the same. Especially, the system 
should allow a simple adjustment of the dosage quantity without making any 
conversion necessary. 
SUMMARY OF THE INVENTION 
The object of the invention is achieved by providing axial openings in the 
syringe flange and plunger accommodations, through which the syringe 
flange and plunger move into their attachment positions, with the data 
carrier being formed as a ring supported on the syringe flange and having 
at least one axially extending sensed area. 
According to an inventive pipette system, the syringe comprises a data 
carrier informing about the syringe and/or the condition thereof. There 
may be concerned any specific dates of the syringe, such as the syringe 
volume, or any other constant data. The information may also relate to any 
other data of the syringe, such as its condition of cleanness or any 
filling substance. Furthermore, the pipette comprises a sensing means 
which reads the information on the data carrier. The pipette thus is in 
the position to identify the syringe associated thereto and/or to 
determine the condition thereof. Consequently, the inventive pipette 
system can automatically determine or adjust the respective pipetting 
parameters. Any time-consuming activities of the user are not necessary 
therefor any more. Especially, an evaluation means may be provided which, 
in consideration of a set value of the plunger adjusting means, converts 
the information read by the sensing means into the value of the actually 
adjusted dosage quantity. This enables the operator to use the syringe 
type according to the practical requirements and to adjust the dosage 
quantity without any time-consuming conversion work. In addition, this 
allows the continuous selection of the dosage quantity within the dosage 
area available. Therefor, the plunger adjusting means only need to be 
adjusted, the dosage quantity being directly displayed by the display 
means. 
According to the physical provision of the information on the data carrier, 
the sensing means can sense mechanically, electrically, optically, 
magnetically, inductively, capacitively and/or acoustically. Mechanical, 
electrical and/or optical modes of operation are acceptable to the 
evaluation means or display means, too. Thereat a miniaturized electric 
circuit or a LCD display may be concerned. 
The syringe can be connected to the pipette by an all-axial movement, 
whereby the mutual alignment of the data carrier and the sensing means may 
be favored. For this purpose, the accommodations for the syringe flange 
and the syringe plunger are provided with axial openings. 
Preferably, the syringe flange of the syringe serves as a data carrier. Any 
large-volume syringes may be of such a big size that there is required an 
adapter comprising a syringe flange for fixing them to a pipette. In that 
case the data carrier can be provided on the syringe flange of the 
adapter. Preferably, the syringe flange is a syringe flange or an adapter 
flange which, at the same time, can serve as a data carrier. 
The information can be contained in the arrangement and axial position of 
sensed areas. The sensed areas are arranged within a ring (e.g. as a 
crenellated ring) to allow the syringe to be inserted into the repeating 
pipette in different rotary positions. Preferably, only two possible 
different axial positions on the syringe are provided for all sensed 
areas. Hereby a binary notation of the information is achieved which makes 
sensing errors largely impossible. Seven sensed areas altogether allow the 
representation of a sufficient number of different syringe volumes which 
fully meets the practical requirements. Thereat any incorrect sensing can 
be noted as well. 
Aligning noses may be provided on the syringe flange and guiding grooves 
may be provided in the flange accommodation of the repeating pipette for a 
reproducible alignment of the syringe and its data carrier with the 
sensing means. Several aligning noses and several guiding grooves allow 
the user to fix the syringe at any desired angle whereat, after an 
automatic alignment, the valuation means determines the volume of the 
syringe, irrespective of the respective angular position. The guides only 
have to cause the sensing means to be in a correct alignment with the data 
carrier. 
The sensing means may be position sensors for detecting the position of 
sensed areas. The position sensors may comprise sensing pins which by 
means of spring means are pressed axially towards the sensed areas of the 
syringe. Thereat the sensing pins preferably can be pressed axially beyond 
the flange abutment for the syringe flange. 
The conversion of the sensed information into the reading for the dosage 
quantity may be made all-mechanically. The sensing pins, however, also may 
be connected to microswitches for making an electronic evaluation. 
According to a preferred embodiment, the sensing pins are defined as axial 
knots of an annular disc of elastic soft material such as silicone. At the 
bottom of a hollow space the knots are provided with an electrically 
conductive material. The annular disc with its knot-free side is secured 
to an annular printed board, whereat several printed boards are associated 
to each knot which printed boards are electrically interconnectable from 
the electrically conductive material. Thereat the knotted side of the 
annular disc may be fixed to the printed board by an annular fastening 
disc having through holes for the knots. In addition, said annular 
fastening disc protects the knots from an excessive compression by the 
syringe flange. This sensing means can be manufactured and installed at 
low cost and features a high operational reliability. 
Moreover, the position sensors may be pressure sensor which in a certain 
position are pressed and switched. Suitable pressure sensors are known 
from the publication "Touch me--Tastaturen mit Druck- und 
Positions-sensoren", Konstruktionspraxis No. 5, May 1993, 23rd year, pages 
84, 85. 
They are also designated as FSR-TM pressure sensors (Force Sensing Resistor 
Touch me pressure sensors). The basic type thereof comprises two polymer 
layers which are laminated together. One layer is covered with 
interdigitating electrodes, the other one with any king of semiconductor 
material. In a no-load condition the output resistance usually is 1M 
.OMEGA. or more. The output resistance falls to typically 400 to 40 k 
.OMEGA. with the surface being in an on-load condition. This change of the 
resistance is used as switching commands. Such pressure sensors feature a 
minimum contact travel only so that, in compensation of any dosage 
differences, they can be kept in the pipette body while being supported by 
a spring. 
Finally, an embodiment provides a repeating system which allows the 
sensing, evaluation and/or display means to be retrofitted. The 
retrofitting, especially, is relevant for electrical systems of the type 
referred to.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 shows a special syringe 1 which allows the absorption capacity to be 
seen. A cylindrical syringe body 2 is provided in a conventional way which 
at the bottom comprises a slip-on cone 3 for a syringe. The end of a 
syringe plunger 4 which is provided with pierces 5 projects from the 
syringe body 2 above. The upper pierce 5 is limited by a plunger collar 6 
above which allows the syringe to be fixed to an accommodation body of a 
repeating pipette. 
Moreover, syringe body 2 comprises a syringe flange 7 at the upper end. The 
syringe flange 7 has a ring 8 consisting of sensed areas 9 which are 
defined as upper side recesses. There are two different kinds of sensed 
areas 9 which correspond to two different depths of said recesses. The 
different kinds of sensed areas 9 thus differ from each other by their 
axial position on the syringe body 2. Ring 8 comprises seven sensed areas 
9 altogether, the information about the maximum absorption volume of the 
syringe 1 being contained in the numbers and arrangements of the different 
recesses. 
FIG. 2 with its parts A to I diagrammatically shows the development of 
various sensed areas 9. Thereat the seven sensed areas 9 are shown 
rectangularly, while the raised sensed areas which activate a sensing pin 
15 of the sensing means 11 are shown blackened. The arrangement of these 
sensed areas shows a pattern of nine different (A to I) possibilities 
which, irrespective of the rotary position of the syringe 1 towards the 
sensing means 11, can be clearly detected and evaluated by the sensing 
means provided in the repeating pipette 23. At the same time, in view of 
the fact that there always is to be evaluated an odd number of raised 
sensed areas only, a false detection in consequence of a defect of a 
sensing pin 15 of said sensing means 11 may be possible which can be 
indicated by the display means since the sensing means then will detect an 
even number of raised areas to be sensed. 
As can be seen from FIG. 1 furthermore, the syringe flange comprises 
aligning noses 10 which taper uwardly. There are provided seven aligning 
noses 10, each of which being arranged between adjacent sensed areas 9. 
A sensing means 11 for the information on the syringe flange 7 will now be 
explained by means of FIG. 3 to 7. The sensing means 11 comprises an 
annular printed circuit board 12 having conducting paths 13 at the upper 
surface. At the side of the conducting paths of the printed circuit board 
12 an annular disc 14 of silicone is arranged. The annular disc 14 
comprises seven knots 15 which, according to the sensed areas 9 of the 
syringe 1, are uniformly distributed around the central axis and thus are 
arranged at an angular distance .alpha. of 51.4.degree.. The knots 15 
comprise a hollow space 16 which towards the side of the conducting path 
13 is open. At the bottom of the hollow space 16 the knots 15 are provided 
with an electrically conductive material 17 in the form of a conductive 
dot or a conductive lacquer. Below the electrically conductive material 17 
the printed circuit board 12 is provided with various conducting paths 13 
which can be electrically connected to each other from the conductive 
material 17 by axially compressing the knot 15. Knots 15 are elastically 
compressible so that they spring back to their basic shape after release. 
The knotted disc 14 is secured to the printed circuit board 12 by means of 
an annular fastening disc 18. The annular fastening disc 18 comprises 
through holes 19 through which the knots 15 do project upwardly. 
Conductor connections 20, 21 are led outwardly at opposite edges of the 
sensing means 11, each of which conductor connection 20, 21 is capable of 
establishing a number of electric connections. Besides, the sensing means 
11 comprises a centering recess 22 on its periphery. 
If pressing the sensing means 11 against the upper side of the syringe 
flange 7 by aligning the knots 15 to the sensed areas 9, the knots 15 are 
compressed by the less deep sensed areas 9 so as to allow the subjacent 
conducting paths 13 to be interconnected by the electrically conductive 
material 17. The remaining knots 15 which penetrate into the deeper 
recesses are not placed into a corresponding switching condition. The 
switching conditions of each of the knots 15 and thus the information 
contained on the syringe flange 7 can be calipered on the electric 
conductor connections 20, 21. 
In FIG. 8 to 11 a repeating pipette system is shown which comprises the 
sensing means 11 and the corresponding syringe 1. The system comprises a 
repeating pipette 23 which in a pipette body 24 has an accommodation 25 
for the syringe flange 7. In the pipette body 24 above the accommodation 
25 a spring-supported abutment 26 is provided which is divided 
perpendicular to the plane of the drawing. 
Moreover, in the pipette body 24 an accommodation body 27 comprising a 
plunger accommodation (not shown) for the syringe plunger 4 is arranged. 
The accommodation body 27 is axially displaceable by means of a driving 
rod 23 and a repeating mechanism (not shown) (e.g. DE-C2 29 26 691). 
In radial breakthroughs of the pipette body 24 gripping levers 29 for the 
syringe flange 7 are arranged so as to face each other diametrically. In 
addition, in radial breakthroughs 30 of the accommodation body 27 gripping 
levers 31 for the plunger collar 6 are arranged in positions facing each 
other diametrically. The syringe gripping levers 29 are provided with cams 
32 inside which can be pivoted against the outside of the collar gripping 
lever 31. 
The pipette body 24 comprises an axial opening 33 for the syringe flange 7 
and the accommodation body 27 is provided with an axial opening 34 for the 
plunger 4. 
According to this pipette means 23, the sensing means 11 is fixed to the 
bottom side of the flange abutment 26, with the knots 15 being directed to 
the axial opening 33 of the body 24. In the proximity of the axial opening 
33 the flange accommodation 25 is equipped with guiding grooves 35 between 
which the aligning noses 10 of the inserted syringe 1 are guided. 
The insertion of the syringe 1 into the repeating pipette 23 and the 
removal therefrom takes place by inserting the syringe 1 with its flange 7 
through the axial opening 33 into the flange accommodation 25. At the same 
time, the syringe plunger 4 is led through the axial opening 34 into the 
accommodation body 27. In their accommodations 25, 27 the syringe flange 7 
and the plunger collar 6 are engaged round and retained by the 
pretensioned gripping levers 29, 31. The guiding grooves 35 cause the 
syringe 1 to be aligned during insertion so that each sensed area 9 is 
associated to exactly one knot 15 of the sending means. 
As soon as the syringe flange is fixed to its accommodation by the syringe 
gripping levers 29 having snapped into place knots 15 of higher sensed 
areas 9 are compressed so as to get into electric contact while the other 
knots remain contactless. In consideration of a desired value of the 
dosage quantity the evaluation and display means (not shown) arranged in 
the repeating pipette 23 evaluate the switching commands provided by the 
sensing means 11 and indicate the respective dosage quantity. 
The ejection of the syringe 1 takes place by actuating the syringe gripping 
levers 29 which with their cams 32 pivot the collar gripping levers 31 so 
as to place them into the release position as well. Thereat the elastic 
knots 15 return to their undeformed initial position in which they project 
from their annular fastening disc 18. They then are ready for the 
detection of another coded syringe 1. 
Needless to say that also compatible uncoded syringes can be inserted which 
can be signalized by the display. If no syringe is inserted the evaluation 
means becomes aware of this and disconnected the display automatically.