Chemical analyser, method for sample-based analysis, device for handling cuvettes,
and loading method
The present invention relates to automatic devices and methods intended for chemical
analyses, In particular, the invention relates to the analysis in automatic analysers of
solutions formed by samples and reagent substances. More specifically, the invention
relates to an analyser and method according to the preambles of Claims 1,10,13, and
20.
Samples have traditionally been examined using analysers, which have changed from
manually operated test devices to automated multi-purpose devices. Present analysers
can perform several different tests and can be used to achieve comparatively short
throughput times, as well as good productivity with low personnel costs. In conventional
automatic analysers, a circular rotatable incubator is traditionally used, on the outer
circumference of which openings are made to receive cuvettes. The cuvettes placed in
the incubators are usually reaction vessels, into which the analyser doses the substance
to be analysed and the reagent substances causing reactions.
A move has taken place from the individual reaction vessels of traditional incubators to
cuvettes, which contain several reaction vessels, which has increased the efficiency of
analysers.
A problem with the type of device described has been the low degree of modularity of
the analysers and the cuvettes they use. In analysers designed for present systems for
large numbers of analyses, there are large incubators, into which a significant number of
cuvettes can be loaded. However, these cuvettes cannot be utilized in analysers intended
for smaller numbers of samples, so that a special type of cuvette is required for each size
of device, which leads to additional purchase and storage costs.
The present invention is intended to eliminate at least some of the defects of the prior art
and for this purpose create a chemical analyser and analysis method, in connection with
which it is possible to use standardized bendable cuvettes, which can receive several
samples.
The chemical analyser according to the invention comprises a rotatable incubator, which
is equipped with openings to receive the cuvettes loaded into it In the analyser, there
are, in addition, analysis means arranged around the incubator and a loading device for
loading the cuvettes into the openings, which are curved. For its part, the analyser-
loading device comprises a feed funnel, by means of which a straight cuvette is bent to
fit into the curved openings of the incubator, and a ram, by means of which the cuvettes
are loaded into the openings of the incubator, through the feed funnel.
More specifically, the chemical analyser according to the invention is characterized by
what is stated in the characterizing portion of Claim 1.
In the method according to the invention for analysing samples, the analysis sequence is
defined sample-specifically, after which a cuvette, which comprises at least two reaction
vessels, into which the sample and the reagent are dosed, is loaded into an opening in the
incubator. In the analysis of the sample, at least one sample in the cuvette is analysed,
the sample being in a reaction vessel.
More specifically, the method according to the invention for analysing sample is
characterized by what is stated in the characterizing portion of Claim 10.
The device according to the invention for handling cuvettes comprises a rotatable
incubator and a loading device. In the incubator, there is at least one curved opening for
receiving and transporting a cuvette. The loading device comprises a loading track for
storing unloaded straight cuvettes and transporting them to the incubator, as well as a
ram, which is arranged to press the cuvette at the incubator end of the loading track into
an opening in the incubator. The loading device also comprises a feed funnel, which is
arranged to receive the straight cuvette pressed by the ram and to bend it to allow it to be
pushed into the curved opening of the incubator.
More specifically, the device according to the invention for handling cuvettes is
characterized by what is stated in the characterizing portion of Claim 13.
In the loading method according to the invention for loading a cuvette into an opening in
an incubator, the cuvette is transported to the location of the opening in the incubator
and loading into the opening in the incubator by moving the ram. During loading, the
cuvette is shaped to fit the opening in the incubator by using the ram to load it through
the curved feed funnel.
More specifically, the loading method according to the invention is characterized by
what is stated in the characterizing portion of Claim 20.
Considerable advantages are gained with the aid of the invention. Thanks to the feed
funnel of the analyser, analysers of different sizes can use same-size standard cuvettes,
which contain several sample vessels. Analysers suitable for standardized cuvettes
receiving many samples permit volume benefits when purchasing cuvettes. The storage
of the cuvettes too is cheap, as only one type of cuvette is required, so that additional
resources are not needed to maintain the articles. In addition, because the cuvette is
straight, it is easier to store than, for example, a curved cuvette.
In the following, embodiments of the invention are examined in greater detail with
reference to the accompanying drawings.
Figure 1 shows a top view of the analyser according to the invention.
Figure 2 shows a perspective view of the analyser of Figure 1.
Figure 3 shows the feed funnel of Figures 1 and 2.
Figure 4 shows the difference between sample-based and test-batch-based analysis.
As can be seen from Figures 1 and 2, the analyser 1 according to the invention
comprises a heated incubator 20, on the outer edge of which openings 21 are made, to
receive cuvettes. The incubator according to the invention is particularly suited for use
with cuvettes that are made from a sufficiently elastic and clear material. The elasticity
permits elastic bending of the connecting web part of the cuvettes relative to its longest
side, while the clearness permits the sample contained in the cuvette to be analysed
through the wall of the cuvette, so that it is not necessary to remove the sample from the
cuvette during analysis. According to the invention, a cuvette 70, which consists of
several reaction vessels and web parts connecting them, is loaded into the openings 21 of
the incubator 20. The cuvette 70 can contain, for example, 10 reaction vessels next to
each other, in such a way that their connecting web parts are parallel to each other, in
which case the orientation of the cuvette 70 is straight and it can receive 10 different
samples. The outermost reaction vessels of a particularly advantageous cuvette 70 are, in
addition, equipped with flexible tongues, with the aid of which the cuvette 70 can be
bent into a curve, without immediately compressing the outermost sample vessels.
Cuvettes like those described, which are especially well suited to the invention, are
disclosed in Finnish patent application 20085509.
The circular incubator 20 according to the invention is mounted on bearings in the centre
and rotation means (not shown) are fitted to it, with the aid of which the incubator 20
can be rotated to the desired extent in the desired direction. The rotation means can
comprise, for example, a servomotor, which has excellent positioning precision, but the
price of which is extremely high. Indeed, the power transmission of the incubator 20 can
be implemented with sufficient precision by fitting it directly to the shaft of a cost-
effective stepped motor, which is sufficiently precise for the purpose, so that there are
only the essential number of moving parts, and thus the minimum number of causes of
play, in the transmission. In the power transmission of the rotation means, it is essential
that the rotational speed and positioning precision are sufficiently great and that
accelerations of the incubator 20 are controlled and soft.
The analyser 1 also comprises a loading device 40 fitted in connection with the incubator
20. The loading device 40 comprises means for delivering the cuvettes 70 to the
incubator 20. The loading device 40 comprises a loading track 50, along which the
cuvettes 70 are brought for loading into the opening 21 of the incubator 20. At its
simplest, the loading track 50 is a trough with a U-shaped cross-section, the bottom of
which is dimensioned to be as wide as the lower edge of the cuvette 70 being loaded and
that the vertical edges of the trough are essentially higher than the cuvette 70. Thus, the
cuvette 70 can be transported on the loading track 50 from its lugs, in such a way that
the lugs of the cuvette 70 are set on top of the vertical edges of the loading track 50, thus
keeping the lower edges of the sample vessel at a distance from the bottom of the
loading track 50. The gap remaining between the lower edge of the cuvette 70 and the
bottom of the loading track 50 ensures that the lower edge of the cuvette 70 does not
drag along the bottom of the loading track 50, and thus does not cause noise or
scratching. Because the cuvettes 70 transported on the loading track 50 are straight, their
transportation is easy and they will not easily jam when being pushed. The cuvettes 70
are transported by a pusher (not shown), which pushes a row of cuvettes 70 suspended
by their lugs forwards to the incubator 20. The pusher can be, for example, a simple
pneumatic cylinder, which can be controlled by remote commands. Alternatively, the
loading track 50 can be sloping, in which case the cuvettes 50 move along the track by
gravitational acceleration, so that there will always be a cuvette 70 at the feed funnel 30,
ready to be loaded. However, more than one cuvette 70 cannot be in the feed funnel 30
at one time, because the shaft of the ram 41 prevents the next cuvette 70 from entering
the funnel during the loading movement.
The feed funnel 30, which is part of the loading device 40 and through which the
cuvettes 70 are fed to the openings 21 of the incubator, is fitted to the end of the loading
track 50 next to the incubator 20. In loading, the loading device's 40 ram 41 is used, the
lower edge of which is arranged to press the cuvette 70 with a single movement into the
feed funnel 30, in which it is arranged to be shaped to fit the opening 21. The curvature
of the opening 21 conforms to the curvature of the outer circumference of incubator 20.
Due to the flexibility of the cuvette 70, it can be used for incubators 20 of several
different sizes, which have different radii of curvature. In this connection, the term
straight refers to a cuvette, the curvature of which has not been changed by bending the
cuvette. Correspondingly, the term a curved cuvette refers to a cuvette, the curvature of
which has been changed by bending the cuvette.
As can be seen from Figure 3, the feed funnel 30 is shaped in such a way that when
travelling through it, a cuvette 70 takes a curved shape suitable for the opening 21, by
means of a single movement of the ram 41. The side 31 of the feed funnel 30 receiving
the cuvette 70 is convex, when examined from the direction of arrival of the cuvette 70,
so that, when pressed against it, the cuvette 70 bends to conform to the circumference of
the incubator 20. The feed funnel 30 is dimensioned in such a way that the curvature of
its lower edge corresponds to the curvature of the openings 21 in the incubator 20. In
other words, it is possible to manufacture different types of feed funnel 30, which suit
incubators 20 of different sizes, in which, however, the same type of cuvette 70 can be
used, which leads to the cost benefits sought by me invention. Because the cuvettes 70
used in the analyser 1 are straight when not in use, they are economical to store.
The curvature of the side 31 of the loading device 40 receiving the feed funnel 30 can be
flat, i.e. constant, or can vary in the vertical direction, in which case the receiving side
31 is planar on its upper edge and curves more steeply convexly when examined
downwards. In that case, the cuvette 70 is arranged to bend in stages according to the
receiving side 31, whereas, when the side 31 is evenly curved, the cuvette 70 is arranged
to bend immediately into the desired curve. The feed funnel 30 is also equipped with
lugs on the receiving side edges, which guide the cuvette laterally. Thus, the cuvette 70
is firmly in contact through only the lugs, so that they take the wear and scratching
caused by bending. Thus, the delicate surfaces of the cuvette 70 are protected from wear.
In addition, the side edges of the feed funnel are equipped which guides 33, which bend
the cuvette into a curve. When the cuvette 70 is pressed onto the lower edge of the feed
funnel 30, its lugs are pressed inwards and its partitions are bent, so that the cuvette 70
lies tightly against the receiving side 31 of the feed funnel 30 and is ready to be loaded
as tightly into the opening 21 of the incubator 20. With the aid of the lugs, the cuvette 70
is positioned and centres itself into the opening 21 of the incubator 20, even though the
incubator 20 may not be in precisely the correct position.
The loading device 40 comprises a vertical guide post 42, to the outer edge of which the
vertically moving ram 41 is fitted. The ram 41 can be moved, for example, by means of
a vertical linear drive, or an electric motor, to the shaft of which a toothed belt is fitted.
The movement of the ram 41 is long enough that, when it presses the cuvette 70
downwards, its upper edge is pressed into the opening 21 at the desired height. The
vertical positioning is thus defined according to the press depth of the ram 41, which
press depth can preferably be adjusted to be suitably programmatically, for example, by
limiting the angle of rotation of the electric motor. As above, when loading the cuvette
70 into the opening 21, its lugs take most of the wear, from which its other surfaces are
protected. After the successful loading of the cuvette 70 pressed into the opening 21 in
the incubator 20, the sample to be analysed, or the reagent substance is dosed into it.
The incubator 20 is heated by electric resistances. There can also be thermal insulation
around the incubator, in order to stabilize the temperature. The heating is intended to
maintain the most favourable analysis conditions, due to which heat is conducted to the
sample vessels of the cuvette 70 and from there to me samples that they contain. For
example, when analysing human samples, the target temperature can be 37°C. However,
when using cuvettes 70 of the type described above, due to the partitions and lugs they
contain, the reaction vessels are separated from each other and from the ends of the
openings 21, so that temperature distortions between the sample vessels are avoided.
Alternatively, the incubator 20 can also be cooled to a target temperature, if the
prevailing temperature is too high. Cooling can be implemented using, for example, a
Peltier element.
The analysis means 60 are arranged around the incubator 20, so that the cuvettes 70 need
not be removed from the opening 21 during the test. For example, according to one
preferred embodiment, the lower part of the cuvette 70 is manufactured from a clear and
transparent material, through which optical tests can be performed directly, without
removing the cuvette 70 from the opening 21. Thus, the recesses of the cuvette 70
loaded into an opening 21 of the incubator 20 from the loading track 50 are arranged to
receive substances from several manipulators, simply by altering the position of the
incubator 20. The analysis procedure can then be arranged, for example, in such a way
that the reagent is dosed into the reaction vessel of the cuvette 70 using a reagent doser,
which takes the substance from a reagent store. The reagent store and doser too are
arranged around the incubator 20. Dosing of a reagent requires the incubator 20 to be
rotated to the correct position, so that the correct reaction vessel of the correct cuvette 70
will be at the reagent reception position. The basic idea of the arrangement is indeed that
the sample is moved in the cuvette 70 that has received it, the position of which is
altered by rotating the incubator 20, so that movements and directions of movement in
the analyser 1 will be as few as possible. The analysis means 60 can also comprise an
analysis device, which sucks the sample from the reaction vessel of the cuvette 70 and
measures its properties inside the device. A conventional analysis device like that
described can be, for example, an ion-selective electrode. The samples are analysed
using an optical analysis method, for instance, photometrically.
The samples to be analysed are dosed under the same conditions as the reagent
substances using a sample doser, which takes the substance from a sample store. The
dosing sequence of sample and reagent substance can vary in a manner required by the
tests in the analysis. The sample and reagent stores are usually carousel-type indexed
stores, the storage locations and positions of which are controlled by remote control as
part of the control of the entire analyser 1. The reagent and sample can be mixed by
rotating the incubator 20 into the vicinity of a separate mixer and starting the mixer. The
content of each reaction vessel can be analysed optically as described above and, for
example, by using a manipulating analyser, which is arranged to suck the sample into its
test chamber and measure its voltage compared to a reference value. The setting and
programming of the test periods and movements is known. There is at least one analysis
station. The number and locations of the analysis devices is limited by the number of
stations that will fit around the incubator.
In the method according to the invention, an apparatus like that described above is used
by sample analysis, in which the analysis event is controlled sample-specifically. A
sample-specific and based test sequence is based on an analyser construction that
permits the flexible arrangement of the periods of the test to be performed, in such a way
that the tests required by each sample can be run one after the other as required. The said
flexibility is based on the analysis means, substance stores, and mixers arranged around
a rotatable incubator. The reaction vessel transporting the sample is then not bound to a
specific path, but can be moved to a desired station as required.
Thus, a sample is dosed into the analyser's 1 reaction vessel, where it remains only for
the time required for dosing, incubation, and mixing. The difference between sample and
test-based analysis is shown in Figure 4. Sample-based analysis leads to a short through-
put time and a possibility to change the test sequence flexibly. The changing of the test
sequence allows, for example, an urgent test to be prioritized to be made before the
analysis of the other samples, without having to wait for the right types of test.
Once the tests for all of the sample vessels used in the cuvette 70 are ready, the cuvette
70 can be removed from the opening 21, in such a way that the ram 41 mat performed
loading pushes the cuvette 70 out of the opening 21 into a separate receiving trash
container, or an exit opening 11 in the frame 10. Alternatively, the ram 41 can load a
new cuvette 70 into the feed funnel 30 through the opening 21, in which case the used
cuvette 70 is pushed by a new cuvette to fall into a separate trash container, or an exit
opening 11 in the frame 10. Alternatively, the analyser 1 can be constructed in such a
way that the cuvettes 70 are loaded into the openings 21 from below, in which case the
loading device 40 with the feed funnel 30 would be arranged beneath the incubator 20.
In that case, however, it would be more difficult to remove the cuvettes 70 from the
openings 21, due to which it is not a preferred embodiment of the invention.
In order to ensure a short throughput time and high productivity, the analyser 1
according to the invention is also, according to one preferred embodiment, equipped
with at least one incubator 20, one reagent store and one sample store, as well as their
dosers or combinations of them, one mixer, and one optical analysis means 60. Thus,
during a single test period, several operations can be performed simultaneously on
different samples. According to one embodiment, for example during an eight-second
period, one sample and one reagent substance can be dosed, two mixtures can be mixed,
and five samples can be analysed.
Claims
1. Chemical analyser (1), which comprises:
- a rotatable incubator (20), in which there are openings (21) for receiving
cuvettes (70);
- analysis means (60) arranged around the incubator (20);
- a loading device (40) for loading cuvettes (70) into the openings (21),
characterized in that
- the openings (21) in the incubator (20) are curved, and that
- the loading device (40) comprises a feed funnel (30), which is arranged to bend
a straight cuvette (70) to fit the opening (21), and a ram (41), which is arranged
to load a cuvette (70) into an opening (21) in the incubator (20) through the feed
funnel (30).
2. Analyser (1) according to Claim 1,
characterized in that
at least some of the analysis means (60) are arranged to analyse the samples
when they are in a cuvette.
3. Analyser (1) according to Claim 1 or 2,
characterized in that
the analyser further comprises a loading track (50), which carries the cuvettes
(70).
4. Analyser (1) according to any of the above Claims,
characterized in that
there is a loading track (50) in it, which has a U-shaped cross-section.
5. Analyser (1) according to any of the above Claims,
characterized in that
the frame (10) is equipped with an exit opening (11), which is arranged to
receive a cuvette (70) removed from an opening (21).
6. Analyser (1) according to any of the above Claims,
characterized in that
the analyser (1) further comprises reagent-substance dosing means, for dosing
reagent substances into the sample vessels.
7. Analyser (1) according to any of the above Claims,
characterized in that
the analyser (1) further comprises sample-dosing means, for dosing samples in
the sample vessels.
8. Analyser (1) according to any of the above Claims,
characterized in that
the analyser (1) further comprises a reagent store, which is at most at the distance
of the operating reach of the reagent-substance dosing means from the incubator
(20).
9. Analyser (1) according to any of the above Claims,
characterized in that
the analyser (1) further comprises a sample store, which is at most at the distance
of the operating reach of the sample-dosing means from the incubator (20).
10. Method for analysing samples on a sample basis, in which method:
- a reaction vessel is loaded into an opening (21) in the incubator (20);
- a reagent and a sample are dosed into the reaction vessel and mixed;
- the sample is measured; and
- the reaction vessel is removed from the incubator (20),
characterized in that
- the analysis sequence is determined sample-specifically;
- a cuvette (70), which comprises more than one reaction vessel, is loaded into
the incubator (20) by shaping it (70) with the aid of a feed funnel (30) to fit the
curved opening (21) in the incubator (20);
- at least one sample in the cuvette (70) is analysed optically when it is in the
sample chamber.
11. Method according to Claim 10
characterized in that
a reagent substance is dosed into the reaction vessel of the cuvette (70).
12. Method according to Claim 10 or 11
characterized in that
the sample is analysed using an optical method.
13. Device for handling cuvettes (70), which device comprises:
- a rotatable incubator (20), in which there is at least one curved opening (21) for
receiving and transporting a cuvette (70);
- a loading device (40), which comprises a loading track (50) for storing empty
straight cuvettes (70) and transporting them to the incubator (20), as well as a
ram (41), which is arranged to push a cuvette (70) at the end of the loading track
(50) next to the incubator (20) into an opening (21) in the incubator (20),
characterized in that
- the loading device (40) further comprises a feed funnel (30), which is arranged
to receive a straight cuvette (70) pushed by the ram (41) and to bend it to be able
to be pushed into the curved opening (21) in the incubator (20).
14. Device according to Claim 13,
characterized in that
the ram (41) of the loading device (40) is arranged to push the cuvette (70)
through the feed funnel (30) in a single movement.
15. Device according to Claim 13 or 14,
characterized in that
the ram (41) of the loading device (40) is arranged to push a used cuvette (70)
out of the opening (21) in the incubator (20).
16. Device according to Claim 15,
characterized in that
the ram (41) of the loading device (40) is arranged to push the used cuvette (70)
out of the opening (21) in the incubator (20) by loading a new cuvette (70) in its
place, so that this displaces the used cuvette (70).
17. Device according to any of Claims 13-16,
characterized in that
the feed funnel (30) is fitted between the ram (41) and the incubator (20).
18. Device according to any of Claims 13 -17,
characterized in that
the feed funnel's (30) surface (31) receiving the cuvette (70) is evenly curved,
which curvature corresponds to the curvature of the opening (21) in the incubator
(20).
19. Device according to any of Claims 13 -17,
characterized in that
the feed runners (30) surface (31) receiving the cuvette (70) is more steeply
curved in the direction of the opening (21) in the incubator (20), in such a way
that the receiving surface (31) corresponds to the curvature of the opening (21) at
the opening (21) end.
20. Loading method for loading a cuvette (70) into an opening (21) in an incubator
(20), in which method:
- the cuvette (70) is transported to the position of the opening (21) in the
incubator (20);
- the cuvette (70) is loaded into the opening (21) in the incubator (20) by moving
a ram (41),
characterized in that
- the cuvette (70) is shaped to fit the opening (21) in the incubator (20) by using
the ram (41) to load it through a curved feed funnel (30).

A chemical analyser, a
method for sample-based analysis, a device
for handling cuvettes, and a loading
method are provided. The chemical analyser
(1) according to the invention comprises
a rotatable incubator (20), in
which there are openings (21) for receiving
cuvettes (70), and analysis means
(60) arranged around the incubator (20),
as well as a loading device (40) for loading
cuvettes (70) into the openings (21).
The loading device (40) of the analyser
(1) comprises a feed funnel (30), which
is arranged to bend a straight cuvette (70)
to fit the opening (21), and a ram (41),
which is arranged to load a cuvette (70)
into an opening (21) in the incubator (20)
through the feed funnel (30).