U.S. patent application number 13/392097 was filed with the patent office on 2012-08-02 for process analyzer.
This patent application is currently assigned to Hach Lange GMBH. Invention is credited to Kai Berggold, Bas De Heij, Aria Farjam, Ulrich Lundgreen, Rolf Uthemann.
Application Number | 20120195799 13/392097 |
Document ID | / |
Family ID | 41130364 |
Filed Date | 2012-08-02 |
United States Patent
Application |
20120195799 |
Kind Code |
A1 |
Farjam; Aria ; et
al. |
August 2, 2012 |
PROCESS ANALYZER
Abstract
A process analyzer for detection of an analyte in a liquid under
analysis includes a base module and an exchangeable cartridge
module. The exchangeable cartridge module comprises a sample taking
device comprising a membrane configured to obtain a sample from the
liquid under analysis. A first pump mechanism is configured to pump
the sample away from the sample taking device. A second pump
mechanism is configured to introduce a reagent into the sample. A
measuring section is configured to perform a quantitative detection
of the analyte in the sample. A degassing device is arranged
downstream of the first pump mechanism and the second pump
mechanism. The degassing device is configured to degas the
sample.
Inventors: |
Farjam; Aria; (Duesseldorf,
DE) ; Uthemann; Rolf; (Leverkusen, DE) ;
Berggold; Kai; (Koeln, DE) ; Lundgreen; Ulrich;
(Guetersloh, DE) ; De Heij; Bas; (Dormagen,
DE) |
Assignee: |
Hach Lange GMBH
Berlin
DE
|
Family ID: |
41130364 |
Appl. No.: |
13/392097 |
Filed: |
April 1, 2010 |
PCT Filed: |
April 1, 2010 |
PCT NO: |
PCT/EP2010/054402 |
371 Date: |
April 20, 2012 |
Current U.S.
Class: |
422/82.05 ;
422/554 |
Current CPC
Class: |
F04B 43/12 20130101;
G01N 2001/4016 20130101; G01N 2021/054 20130101; B01L 3/50273
20130101; G01N 33/18 20130101; G01N 21/8507 20130101; B01L 2200/10
20130101; G01N 2201/024 20130101; B01L 2300/0627 20130101; G01N
21/05 20130101; G01N 21/645 20130101; G01N 2021/0346 20130101; B01L
2400/0481 20130101; G01N 21/11 20130101; G01N 2021/0325 20130101;
G01N 2021/8411 20130101; G01N 21/78 20130101; G01N 2021/0321
20130101; G01N 35/1095 20130101; B01L 3/502715 20130101; F04B
43/082 20130101; G01N 2201/0218 20130101 |
Class at
Publication: |
422/82.05 ;
422/554 |
International
Class: |
G01N 21/75 20060101
G01N021/75; B01L 3/00 20060101 B01L003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 25, 2009 |
EP |
09168536.2 |
Claims
1-12. (canceled)
13: A process analyzer for detection of an analyte in a liquid
under analysis, the process analyzer consisting of: a base module;
and an exchangeable cartridge module, the exchangeable cartridge
module comprising: a sample taking device comprising a membrane
configured to obtain a sample from the liquid under analysis, a
first pump mechanism configured to pump the sample away from the
sample taking device, a second pump mechanism configured to
introduce a reagent into the sample, a measuring section configured
to perform a quantitative detection of the analyte in the sample,
and a degassing device arranged downstream of the first pump
mechanism and the second pump mechanism, the degassing device being
configured to degas the sample.
14: The process analyzer as recited in claim 13, further comprising
a base-module-side pneumatic pump configured to pneumatically drive
the first pump mechanism and the second pump mechanism, wherein the
degassing device includes a gas-permeable degassing membrane which
is connected to the base-module-side pneumatic pump so as to
generate an underpressure on a gas side of the gas-permeable
degassing membrane.
15: The process analyzer as recited in claim 14, wherein the
degassing device is formed by a degassing channel having a groove
shape, the degassing channel being covered by the gas-permeable
degassing membrane.
16: The process analyzer as recited in claim 15, wherein the
degassing channel has a meandering course.
17: The process analyzer as recited in claim 15, wherein a volume
of the degassing channel is at least as large as a volume of the
measuring section.
18: The process analyzer as recited in claim 15, further comprising
a dialysis chamber disposed proximally to a dialysis membrane and
an introduced reagent, wherein a volume of the degassing channel is
at least as large as a sum of the volumes of the dialysis chamber
and the introduced reagent.
19: The process analyzer as recited in claim 15, wherein the
degassing channel is provided as a reaction chamber in which a
mixture of the sample and the reagent dwells at least 10 seconds
before being pumped to the measuring section.
20: The process analyzer as recited in claim 13, wherein the
degassing device includes a degassing membrane.
21: The process analyzer as recited in claim 20, wherein the
degassing membrane is a hydrophobic membrane.
22: The process analyzer as recited in claim 13, wherein the
exchangeable cartridge module further comprises a carrier liquid
supply tank and a reagent supply tank.
23: The process analyzer as recited in claim 13, wherein the base
module comprises a photometric analyte sensor which is functionally
associated with the measuring section.
24: The process analyzer as recited in claim 13, wherein the
degassing device is arranged between the first pump mechanism and
the second pump mechanism, and the measuring section.
25: The process analyzer as recited in claim 13, wherein the
degassing device is configured to degas the measuring section.
26: A cartridge module for a base module, wherein the cartridge
module comprises: a sample taking device comprising a membrane
configured to obtain a sample from a liquid under analysis, a first
pump mechanism configured to pump the sample away from the sample
taking device, a second pump mechanism configured to introduce a
reagent into the sample, a measuring section configured to perform
a quantitative detection of an analyte in the sample, and a
degassing device arranged downstream of the first pump mechanism
and the second pump mechanism, the degassing device being
configured to degas at least one of the sample and the measuring
section.
27: The cartridge module as recited in claim 26, wherein the
cartridge module further comprises a carrier liquid supply tank and
a reagent supply tank.
28: The cartridge module as recited in claim 26, wherein the
degassing device is arranged between the first pump mechanism and
the second pump mechanism, and the measuring section.
29: A cartridge module for a base module, wherein the cartridge
module comprises: a sample taking device comprising a membrane
configured to obtain a sample from a liquid under analysis, a first
pump mechanism configured to pump the sample away from the sample
taking device, a second pump mechanism configured to introduce a
reagent into the sample, a measuring section configured to perform
a quantitative detection of an analyte in the sample, a degassing
device comprising a gas-permeable degassing membrane, the degassing
device being arranged downstream of the first pump mechanism and
the second pump mechanism, and being configured to degas at least
one of the sample and the measuring section, and a base-module-side
pneumatic pump configured to pneumatically drive the first pump
mechanism and the second pump mechanism, wherein, the gas-permeable
degassing membrane is connected to the base-module-side pneumatic
pump so as to generate an underpressure on a gas side of the
gas-permeable degassing membrane; and the base module comprises: a
photometric analyte sensor which is functionally associated with
the measuring section.
30: The cartridge module as recited in claim 29, wherein the
cartridge module further comprises a carrier liquid supply tank and
a reagent supply tank.
31: The cartridge module as recited in claim 29, wherein the
degassing device is arranged between the first pump mechanism and
the second pump mechanism, and the measuring section.
Description
CROSS REFERENCE TO PRIOR APPLICATIONS
[0001] This application is a U.S. National Phase application under
35 U.S.C. .sctn.371 of International Application No.
PCT/EP2010/054402, filed on Apr. 1, 2010 and which claims benefit
to European Patent Application No. 09168536.2, filed on Aug. 25,
2009. The International Application was published in German on Mar.
3, 2011 as WO 2011/023421 A1 under PCT Article 21(2).
FIELD
[0002] The present invention provides a process analyzer for
determining an analyte in a liquid under analysis, and can be used,
for example, as an immersion probe, a swimming probe, a tube probe
or as a laboratory analyzer.
BACKGROUND
[0003] Process analyzers quasi-continuously perform analyses for a
quantitative determination of an analyte in a liquid under
analysis, such as in water, and find application, for example, in
waste water treatment or drinking water control.
[0004] Since a process analyzer is generally not used in
laboratories, and maintenance, repair, and refilling carrier liquid
and reagents entail considerable effort, modular process analyzers
are now available wherein low-maintenance or maintenance-free
components are arranged in a base module, and components that are
delicate, exposed to wear, or which contain reagents, are arranged
in an exchangeable cartridge module. It is also possible to provide
a plurality of different exchangeable cartridge modules, for
example, comprising reservoir tanks and fluidic systems.
[0005] A modular structure of a process analyzer is described, for
example, in EP 0 706 659 B1. A part of the fluidic system and a
dialysis membrane are therein arranged in a cartridge module,
whereas the pumps and the reservoir tanks for the carrier liquid
and the reagent are provided in the base module.
[0006] It is desirable in principle to also arrange the used
material, i.e., the carrier liquid and the reagent, in the
cartridge module. However, this requires that only rather small
volumes of carrier liquid and reagent are used. This, in turn, can
be achieved by designing the fluidic system as a so-called
microfluidic system, i.e., by designing the liquid conduits with
small sectional areas, for example, sectional areas of less than a
few square millimeters. Microfluidic systems are, however,
inherently more trouble-prone than fluidic systems with larger
sections.
SUMMARY
[0007] An aspect of the present invention is to provide a process
analyzer comprising a base module and an exchangeable cartridge
module, which analyzer is reliable and in which the reagent is
stored in the cartridge module.
[0008] In an embodiment, the present invention provides a process
analyzer for detection of an analyte in a liquid under analysis
which includes a base module and an exchangeable cartridge module.
The exchangeable cartridge module comprises a sample taking device
comprising a membrane configured to obtain a sample from the liquid
under analysis. A first pump mechanism is configured to pump the
sample away from the sample taking device. A second pump mechanism
is configured to introduce a reagent into the sample. A measuring
section is configured to perform a quantitative detection of the
analyte in the sample. A degassing device is arranged downstream of
the first pump mechanism and the second pump mechanism. The
degassing device is configured to degas the sample.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The present invention is described in greater detail below
on the basis of embodiments and of the drawings in which:
[0010] FIG. 1 shows a schematic illustration of a process analyzer
formed by a base module and an exchangeable cartridge module;
[0011] FIG. 2 shows a longitudinal section of an embodiment of an
analyzer;
[0012] FIG. 3 shows a top plan view on the cartridge module of the
analyzer in FIG. 2; and
[0013] FIG. 4 shows an embodiment of a degassing device of an
analyzer cartridge module.
DETAILED DESCRIPTION
[0014] The process analyzer of the present invention is formed by a
base module which is basically not exchangeable and an exchangeable
cartridge module that can be exchanged with little effort at
regular intervals, for example, when the carrier liquid supply or
the reagent supply is depleted or a component is defective. The
cartridge module includes the entire fluidic system which can, for
example, be of a microfluidic design, i.e., all liquid carrying
elements have very small volumes or very small sectional areas of a
few square millimeters at most, for example, a maximum of 10 square
millimeters, or, for example, of less than five square
millimeters.
[0015] In an embodiment of the present invention, the cartridge
module comprises a sample taking device, for example, a dialysis
device, with a membrane, for example, a dialysis membrane, for
obtaining a sample, for example, a dialysate, from the liquid under
analysis. In case of a dialysis, the sample is a dialysate formed
by a carrier liquid and the analyte from the liquid under analysis,
with the analyte migrating through the membrane into the carrier
liquid. A first pump mechanism is provided for the purpose of
pumping the carrier liquid from a carrier liquid reservoir tank
which can, for example, be arranged in the cartridge module, to the
sample taking device. A pump mechanism is to be understood as a
mechanical system that pumps a liquid. The pump mechanism can, for
example, be designed as a displacement pump. The pump mechanism is
driven by an actuator system that can, for example, be arranged in
the base module separately from the pump mechanism. The cartridge
module can thus, for example, not include an actuator system. No
carrier liquid reservoir tank is provided if the sample taking
device is a filter for filtering a sample.
[0016] In an embodiment of the present invention, the cartridge
module comprises a second pump mechanism for introducing a reagent
from a reagent reservoir tank into the sample. It also applies to
the second pump mechanism that the associated actuator system can,
for example, be arranged in the base module. The cartridge module
further comprises a measuring section for the quantitative
determination of the analyte in the sample or in the dialysate. The
measuring section can, for example, be an optical measuring section
for the photometric quantitative determination of an analyte.
[0017] The cartridge module further comprises a degassing device
for degassing the sample or the dialysate in the course of the
liquid conduit that leads from the sample taking device to beyond
the measuring section, the degassing device being arranged behind
the two pump mechanisms. Seen in the flow direction, the degassing
device is thus arranged behind the sample taking device and behind
the two pump mechanisms. By arranging the degassing device behind
the pump mechanisms, it is provided that gas bubbles are removed
from the sample before the same flows into the measuring section.
This is important because gas bubbles can lead to substantial
errors during measurement, for example, in an optical measuring
section in which the analyte is quantitatively determined by
photometry.
[0018] Gas bubbles may be formed in a sample when the sample in the
cartridge module becomes warmer, for example, due to a warm liquid
under analysis that is present at the dialysis membrane. An acid
reagent in the sample can further expel carbon dioxide gas. By
arranging the degassing device behind the point where the reagent
is introduced into the sample, it is provided that the expelled
carbon dioxide gas is also removed from the sample before the
sample flows into the measuring section. Reliability, measuring
certainty and measuring accuracy are thus improved.
[0019] In an embodiment of the present invention, both pump
mechanisms can, for example, be driven pneumatically by a pneumatic
pump on the base module side. The pressure side of the pneumatic
pump may be connected to an overpressure accumulator, and the
suction side may be connected to a vacuum accumulator. The
overpressure accumulator and the vacuum accumulator are arranged in
the base module.
[0020] In an embodiment of the present invention, the degassing
device comprises a gas-permeable degassing membrane which is
connected to the pneumatic pump of the base module to generate a
vacuum on the gas side of the degassing membrane. The pump
mechanisms may, for example, be designed as pneumatically driven
peristaltic pumps, each having two or three pump chambers. A single
pneumatic pump can thus form both the actuator system of the two
pump mechanisms and generate the vacuum on the gas side of the
degassing membrane. For this purpose, it is merely necessary to
provide corresponding valves to control the pump mechanisms or the
peristaltic pumps, respectively. The reduction to a single
pneumatic pump for driving the pump mechanisms and for the
degassing device results in a substantial reduction in design
effort and manufacturing effort. Less energy is further required
for the operation of the analyzer which is of great importance in
particular with battery-powered analyzers.
[0021] In an embodiment of the present invention, the degassing
device can, for example, be formed by a groove-shaped degassing
channel covered by a gas-permeable degassing membrane. The
degassing channel may, for example, be formed as a groove in an
injection molded base plate on which the degassing membrane is
fastened in the region of the degassing device, e.g., by gluing or
welding. The degassing channel can, for example, extend in a
meandering manner. This allows realizing the degassing device and
the degassing membrane with rather small areas. The degassing
membrane can, for example, be configured as a hydrophobic membrane,
for example, a Teflon membrane.
[0022] The volume of the degassing channel can, for example, be at
least as large as the volume of the measuring section. It is
thereby provided that the entire measuring section can be filled
with a degassed sample volume and that there is no part of the
sample in the measuring section that is not degassed.
[0023] In an embodiment of the present invention, the volume of the
degassing channel can, for example, be at least as large as the sum
of the volumes of the space proximal of the membrane of the sample
taking device and the reagent introduced. In this manner, all of
the sample volume of a measuring cycle, mixed with the reagent, can
be degassed in the degassing device. Irrespective of which part of
this sample volume eventually fills the measuring section, it is
thus provided that the sample volume that has reached the measuring
section has been degassed.
[0024] In an embodiment of the present invention, the degassing
channel can, for example, be a reaction space in which the mixture
of sample and reagent dwells for at least 10 seconds before it is
pumped to the measuring section. A separate reaction chamber, used
to wait for the reaction of the reagent with the analyte in the
sample, is not needed. If the reagent is acidic and expels carbon
dioxide gas from the sample, it is thus provided that the carbon
dioxide gas is withdrawn from the sample at the very site at which
it is formed. A change in the volume of the sample during the
reaction with the reagent is thus avoided. The sample/reagent
mixture dwells in the reaction space until the reaction of the
reagent and the analyte is substantially finished. It is thereby
provided that no further carbon dioxide gas is expelled from the
sample after it has left the degassing device, which gas could
impair or corrupt the subsequent measurement in the measuring
section.
[0025] In an embodiment of the present invention, the cartridge
module can, for example, comprise a carrier liquid reservoir tank
and a reagent reservoir tank. The entire fluidic system is thus
arranged in the cartridge module. The volumes of the two reservoir
tanks are designed such that the reservoir will last for the
duration of the normal mechanical functionality of the cartridge
module. In this respect, it is feasible to dimension the entire
fluidic system as a microfluidic system. The reservoir tanks may be
provided on the cartridge module such that they are
exchangeable.
[0026] In an embodiment of the present invention, the base module
can, for example, comprise a photometric analyte sensor that is
functionally associated to the measuring section on the cartridge
module side. The base module thus comprises a photometer, wherein
the measuring section of the photometer is formed by the measuring
section in the cartridge module when the cartridge module is placed
in the base module.
[0027] In an embodiment of the present invention, the degassing
device can, for example, be arranged between the two pump
mechanisms on the one hand and the measuring section on the other
hand. It is thereby provided that the dialysate is completely
degassed before entering the measuring section. The degassing
device or the degassing channel, respectively, can, for example, be
arranged immediately upstream of the measuring section. As an
alternative or in addition, the degassing device may also be
arranged along the measuring section itself. In this manner, the
dialysate can also be degassed during the measurement in the
measuring section. This is feasible for a photometric measuring
section since gas bubbles may corrupt photometric measurement
results, especially if the measuring section is a microfluidic
measuring section.
[0028] FIG. 1 is a schematic illustration of a process analyzer 10
for a continuous or quasi-continuous quantitative photometric
determination of an analyte, for example, phosphate, ammonium or
nitrate, in water. The analyzer 10 is a stationary analyzer 10 and
is mounted immersed in an aqueous liquid 11 under analysis, i.e.,
it is designed as a so-called immersion probe. The analyzer 10
comprises a base module 12 rigidly suspended from a tubing 13 and
hanging in or just above the liquid 11 under analysis, and an
exchangeable cartridge module 14 removably fastened to the base
module 12 and immersed into the liquid 11 under analysis.
[0029] The entire fluidic system of the analyzer 10 is provided in
the cartridge module 14. The cartridge module 14 comprises a
carrier liquid reservoir tank 26 with a carrier liquid 24 connected
to a sample taking device 16 via a conduit, which device is a
dialysis device 16 in the present case. As its membrane 18, the
dialysis device 16 has a dialysis membrane 18 that separates the
dialysis chamber 52, in which the carrier liquid dwells during the
dialysis, from the liquid 11 under analysis. The dialysis chamber
52 may, for example, be formed by a meandering groove whose grove
opening is closed by the dialysis membrane 18. A first pump
mechanism 22 is provided behind the dialysis device 16, the pump
mechanism pumping the sample 20 or the dialysate from the dialysis
device 16 to a degassing device 40.
[0030] The cartridge module 14 comprises a reagent reservoir tank
34 containing a liquid reagent 30 pumped to the degassing device 40
by a second pump mechanism 28. A standard solution reservoir tank
56 containing a standard solution 58 is further provided in the
cartridge module 14, wherein a third pump mechanism 54 is provided
downstream of the standard solution reservoir tank 56, seen in the
flow direction, which pump mechanism pumps the standard solution to
the degassing device 40, if needed
[0031] The three pump mechanisms 22, 28, 54 converge in a
star-shaped manner just before the degassing device 40, as is
particularly well visible in FIG. 3. The degassing device 40 is
formed by a groove-shaped degassing channel 48 covered by a
gas-permeable and liquid-tight degassing membrane 44 which is a
hydrophobic Teflon membrane. The degassing channel extends in a
meandering manner so that a relatively long degassing channel 48 is
realized in a small area. On the side of the degassing membrane 44
opposite the degassing channel 48, the gas side 46 of the degassing
device is arranged whose evacuation is controlled through a
degassing valve 70 on the base module side.
[0032] The sample flows from the degassing device 40 to a
photometer measuring section 32 and from there into a waste liquid
tank 60 in which the waste liquid 62 is collected. The photometer
measuring section 32 is functionally associated to a photometer 50
on the base module side which has a light source 64 and a receiver
66 between which a section of the dialysate conduit is arranged in
the longitudinal direction, which section forms the photometer
measuring section. In the present case, the analyte sensor 50 is
designed as a transmission photometer. Alternatively, the
photometer may, however, also be designed as a reflection
photometer 50', as illustrated in the embodiment in FIG. 2.
[0033] The pressure sources for driving the three pump mechanisms
22, 54, 28 are an overpressure accumulator 72 and a vacuum
accumulator 76 in the base module 12. The three pump mechanisms 22,
54, 28 are designed as pneumatic peristaltic pumps. A respective
pump actuator system 78 is associated to each pump mechanism 22,
54, 28, each actuator system being formed by three change-over
valves 86. Each pump mechanism 21, 54, 28 respectively comprises
three pump chambers 80 with respective elastic pump membrane 82
made of rubber or an elastic plastic material.
[0034] The rear side of each pump membrane 82 is connected to a
change-over valve 86 via a pneumatic control conduit 84 on the
cartridge module side, a control conduit coupling 87 and a
pneumatic control conduit 85 on the base module side, the
change-over valve selectively connecting the pump membrane 82 with
the overpressure accumulator 72 or the vacuum accumulator 76. In
this manner, either an overpressure or a vacuum is applied to the
rear side of the pump membrane 82 so that the pump chambers 80 are
filled or emptied. By successively filling and emptying the three
pump chambers 22, 54, 28, a peristaltic pumping movement is
caused.
[0035] For the purpose of generating a vacuum in the vacuum
accumulator 76 and an overpressure in the overpressure accumulator
72, a pneumatic pump 42 is provided in the base module 12, whose
pump inlet is connected to the vacuum accumulator 76 and whose pump
outlet is connected with the overpressure accumulator 72. The
pneumatic pump 42 is driven continuously by an electric pneumatic
pump motor 43. The vacuum in the vacuum accumulator 76 and the
overpressure in the overpressure accumulator 72 are limited,
respectively, by a corresponding vacuum valve 88 or an overpressure
valve 74, each connected to atmospheric air pressure. As an
alternative, the pressure sensors may be provided in the
accumulators, by means of which the pneumatic pump is activated or
deactivated when pressure falls below a limit pressure or exceeds
the same.
[0036] The degassing valve 70 controlling the vacuum in the
degassing device 40 is connected to the vacuum accumulator 76.
[0037] All valves 86, 70 and the photometer 50 are controlled by a
central control 68. All electric components are arranged in the
base module 12.
[0038] FIGS. 2 and 3 illustrate an embodiment of an analyzer or a
cartridge module 14, respectively. A difference from the embodiment
illustrated merely schematically in FIG. 1 is the concrete design
of the three pump mechanisms 22', whose respective last pump
chamber 80' is formed by a single common pump chamber 80'. Another
difference in FIG. 2 is the design of the analyte sensor 50' as a
reflection photometer.
[0039] As is clearly visible in FIGS. 2 and 3, the cartridge module
14 is substantially formed by a plate-shaped plastic part
comprising the fluidic system conduits, the pump chambers 80, 80',
the dialysis module 16, the degassing device 40 as well as the
measuring section 32', and by the tanks 26, 34, 56, 62 set on the
plate-shaped plastic part.
[0040] FIG. 4 illustrates an embodiment of a degassing device 40',
wherein a part of the degassing channel 48 at the same time forms
the photometer measuring section 32.
[0041] For all embodiments of the degassing device 40, 40', the
volume of the entire degassing channel 48 is at least as large as
the sum of the volumes of the dialysis chamber 52 proximally of the
dialysis membrane 18 and the introduced reagent 30.
[0042] The present invention is not limited to embodiments
described herein; reference should be had to the appended
claims.
* * * * *