Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The present inven~ion relates to an apparatus
for use in connection with spectroscopic analysis of
properties of test samples, and more particularly to an
5 apparatus for providing the capability of spectro-
scopically analy~ing a plurality of tes~ samples in a
relatively quick and efficient manner. The present
invention may be used in connection with many different
types of spectroscopic analysis systems, including those
10 for making both quantitative and qualitative. analysis oftest samples. For example, the apparatus of the present
invention may be used in connection with spectroscopic
analysis based upon light absorption principles and
fluorescence emission principles.
Spectroscopic analysis of substances yenerally
involves exposing a test sample or substance to a beam of
radiation, and then detecting and analyzing the output
radiation from the test sample. The information derived
20 from such analysis may be used for quantitatively and/or
qualitatively determinin~ properties of the test sample.
For exarnple, spectroscopic analysis may be used in con-
nection with qualitatively determining the concentration
of a particular substance in a test solution, such as by
25 determining the drop in intensity of radiation translnit-
ted through the test soluti.on. An example of qualitativc
analysis is the determination of the particular materials
or elements contained in the test solution by virt~e of a
determir;ation of the wavelength of light either absorbed
30 or emitted from the test solution. ~s is wel]. kno,n~
spectroscopic anaylsis may be based upon eit~er the
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dbsorption speetrum, in vlhich the substallce is studied by
its selective absorption of radiation, or the
fluorescence spectrum, in which the substance is studied
by the radiation it emits when excited by radiation of
5 another frequency.
When spectroscopic analysis is to be performed
with respect to a large number of samples, such as for
eY~ample in determining -t}le concentra-tion of substances in
various solutions, it is desirable to conduct such
lO spectroscopic analysis as rapidly as possible so that the
same basic scanning and detector apparatus may be used in
connection with a plurality of samples. In analyzing
multip~e samples, most prior art systems employ various
means for moving the samples into and out of position for
15 testing with the scanning and detector apparatus. For
example, one known prior art system employs a carousel
arrangement in which samples are disposed around the
carousel and the carousel then rotated on its axis so
that the samples pass sequentially between a light source
20 and detector. Other prior art systems involve the move-
ment of the test sample in a linear mode between a li~ht
source and detector.
Another known technique for spectroscopically
analyzing a plurality of test samples has been to provide
25 a stationary test ccll or container and then to introduce
and withdraw sample solutions therefrom. This technique
is particularly useful in connection ~ith spectroscopic
analysis of varying or changin~ test solutions in which
it is clesired to o~tain multiple readings over a period
30 of time. Thus, in known systems for analyzing a single
test solution, a vial or test cell is placed between a
scanner and a dctector, and the test solution continu-
ously pumped throu~3h the~ test cell. This may be
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accomp]ished by connectirl~ inlet alld outle~ corlduits to
the test ce1l. In t~lis manner, repeated anaiysis may be
preferred on t~le test solution at periodic intervals or
even continuously to provide a continuous updating of the
5 properties being analy~ed.
~ hile such known prior art systems for spectro-
scopically analyzincJ a plurality of test samples havc
proven to be generally satisfactory either with respect
to self-contained test samples, or with respect -to a
10 single varyin~ or changing test solution, difficulties
have arisen in connection with spectroscopica]ly
analyzing a plurality of varying or changing test
samples. This is for the reason that with conventional
systems in which the sample cells are moved relative to
15 the spectroscopic analysis equipment, some means must be
provided for allowing movement of the test cells having
input and output conduits coupled to each of a plurality
of individual test cells. That is, where the spectro-
scopic analysis system is being used to conduct spectro-
20 scopic analysis of a plurality of constantly changingtest solutions, the test cells include fluid lines
coupled thereto for the continuous introduction and with-
drawal of the solution to be tested. Thus, when a
plurality of such test cells are to be analyzed with the
25 same scanning and detector equipment, provision must be
made for physical movement of the test cells without
completely tangling or fouling the fluid lines. Accord-
ingly, with one known apparatus, a small plurality of
test cells are supported on a movable support member,
30 such as for example a turret, with the f]uid lines for
the various cells leadinc~ thereawayfrom. In order to
prevent tanglin~ or fouling of the fluid lines, it is
necessary to reverse the movement of the movable support
member after all of the cells ilave been tested so as to
~5 untangle the lines. Sucl-l an arrangement, however, wo~lc~
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be totally unsatisfactory for ~s~ in conn~?etion with
cond~ting an analysis of a lar~ye num~er of tcst cclls.
~urthermore, with prior art syst~ms in ~hich test cel]s
are movecl into and out of alignment ~ith the scanner and
5 detector equipment, the rate at which the test cells are
moved is relatively slow. This is most significant and
limits the usefulness of the prior art systems in con-
nection with spectroscopical analysis of test samples in
which fast chemical reactions take place and/or test
lO samples in flow through test cells where the properties
of the test samples rapidly change.
In accordance with the present invention there is
provided an apparatus for use in spectroscopically analyzing
properties of a plurality of test samples, said apparatus5 comprising:
annular support means for stationarily supporting a
plurality of test cells for containing test samples to be
analyzed, said plurality of test cells supported in an annular
array about the central axis of said annular support means, said
20 support means including passageways aligned with said test cells
to permit light to pass therethrough;
radiation directing means positioned on said central
axis for directing a beam of radiation at said test cells;
radiation detector means positioned on the opposite
25 sides of said test cells from said radiation directing means for
receiving radiation transmitted through said test cells;
mounting means for mounting said radiation directing
means and said radiation detector means in a fixed relationship
to one another, said mounting means being arranged with respect
30 to said support means so that when said beam of radiation from
said radiation directing means is directed at one of said test
cells, said radiation detector means receives radiation
transmitted through said one test cell; and
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rotating means for eotating said mounting means about
said central axis so as to successively direct a beam of
radiation from said radiation directing means radially outwardly
reLative to said central axis and at each of said plurality of
test cells so that said radiation detector means will
successively receive radiation radially transmitted through each
of said plurality of test cells.
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Such an arral-lyelnent in which the test samples
are stationarilY supported relative to t~le beam of radia-
tion ar~ the detec,~or means is most. advarltageous itl
connection with an apparatus for use in spectr.oscopically
s analyzing propcrties of a plurality of tcst cells whose
contents arc constantly changing. More sp,ecifically, with
the apparatus of the present invention, the introduction
into and withdrawal of the test solution from the test
cells may be easily facilitated since the test cells
10 remain stationary; there is no necessity of having to
provide for physical movement of the introduction and
withdrawal conduits.
In acoordance Wlt:ll a preferr~d ~mbx~ent, the radiation directing means
is arranged at the central axis of the annular arra~ and
carries a support arm which extends radially outward from
the radiation directing means. The radiation detector
means is supported by the support arm so as to be in a,
20 position to receive output radiation from the corre-
sponding test cells at which the radiation directing
means directs the beam of radiation. Thc radiation direct~
ing means, detector means and radially extending support
arm are rotated together about the axis of the annular
25 array of test cells so as to sùccessively direct the beam
of radiation from the radiation directin~ means at test
cells. When the apparatus is being used in connection
with spectroscopic concentration analysis of the test
cells, the radiation directing means directs a beam of
30 radiation through the test cell and the radi.ation
detector means is located on the opposi~e side of the
test cells to receive the output radiation passiny there-
through.
Still further in accordance with the preferred
35 embodiment, a source of radiation is provided f'or
transmit~ing a source beam of radiation alorlg the axis o~
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l:he annular array of test cc~ls. Th(- ra~ial:ion direc~ing
means comprises a rnirror and lens arrangerllcnt for direct-
ir~g tlle beam of radiation from the source ra~ially out-
ward from ~he axis of the annular s~pport towards the
5 detector nleans.
These and further features and characteristics
of the present invention will be apparent from the
following detailed description in which reference is made
to the enclosed drawings which illustrate a preferred
lO e~n~odiment of the present invention.
In the accompanying drawlngs:
Figure l is a schematic plan view illustratin~
operation of the apparatus in accordance ~ith the pre-
ferred embodiment of the present invention.
Figure ~ is a perspective view, partially
broken away, of the preferred embodiment of the apparatus
in accordance with the present invention.
Figure 3 is a top plan view of the apparatus
shown in ~igure Z.
Figure 4 is a side sectional view of the
apparatus taken along lines 4-4 of Figure 3 and illus-
trating schematically a suitable radiation source for
transmitting a beam of radiation along the axis of rota-
tion of the apparatus.
Figure 5 is a sectional view taken along
lines 5-5 of Figure 4.
As the apparatus lO of the present invention is
particularly useful in connection with obtaining concen-
30 tration measurements of a plurality of constantly chang-
ing test solutions, the present invention will be
described rnainly with respect to an apparatus for such
particular use. However, it should be appreciated that
the prcsent invention is not limited to such use; rather,
3~ the apparatus 10 may be used in connection with spectro-
scopic analysis of many other types of properties of test
salnp~cs, both from the vicwpo-int of qllalitative analysis
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and c~u~ntitative analysis arlc~ mcly be llsed in connection
with such analysis blsed on either absorption or
flourescence spectra. Furthermore the present invention
may be used in connection with spec-troscopically
5 analyzing other types of test samples.
Referring now to the dra~ings wherein like
reference characters represent like elements there is
illustrated in Figure 1 an apparatus in accordance with
the preferred embodiment of the present invention for use
10 in spectroscopically analyzing properties of a plurality
of fluid test samples. The basic operation of the
apparatus 10 in accordance with the presen-t invention is
illustrated schematically in Figure 1. The apparatus 10
includes a suitable stationary support means 12 for
15 stationarily supporting a plurality of test cells 1~ to
be analyzed. As the apparatus 10 in the preferred embodi-
ment comprises a spectrophotometer for use in connection
with obtaining concentration data of fluid test samples,
the support means 12 includes a plurality of tes-t cells
20 or cavities 14 for receiving and holding fluid
containers 16 into which fluid test samples are
deposited. In the preferred embodiment th~ test cells 14
are arranged in an annular array about the central
axis 18 of the apparatus 10. The appara-tus 10 also
25 includes radiation directing means 20 for directing a
beam of radiation radially outward from the central
axis 1~ for impinging on the test cells 14 annularly
arranged thereabout. In this regard each of the test
cells 14 includes suitab]e passagewa~s 2~. 2~ arranged
30 with respect to the fluid samples for a:Llo~ing lighl or
other radiation to pass thereinto and through the
solution and to then exit from the cells 1~. The passage-
ways 22 2~ for example may comprise openings in the
walls defining the inner and ou-ter annular surfaces 25,
28 of the test cells 1~,. I`he ra~iation directing means 20
is axially arranged with respect to the support means 12
and test cells 14 so that the radially outwardl~ directed
5 beam of radiation will pass through the inner radiation
passageways 22 of the cells 14 and be intercepted by the
test solutions in each of the various cells 14. A suit-
able radiation detector 30 is arranged with respect to
the stationarily supported test cells 14 for receiving
10 output radiation exiting from the test cells 14. As the
apparatus 10 is mainly intended for use in connection
with obtaining concentration measurements, based on the
amount of radiation absorbed by the substance in the
solutions being tested, the detector 30 in the preferred
15 embodiment is arranged in alignment with the radially
outwardly d:irected beam so that when the beam passes
through the solution in one of the test cells 14 and
exits through the outer radiation passageway 24, the
detector 30 will detect the intensity of the radiation
20 exiting from the cells 14.
In order to insure alignment between the
radially outward directed beam and the detector 30, the
detector 30 is fixedly mounted on a support arm 32
extending radially outward from the radiation directing
25 means 20 so as to be in direct alignment with the
outwardly directed beam exiting from the radiation
directing means 20 and so as to rotate with rotation of
the radiation directing means 20. As the arm 32 is
rotated, it will be appreciated from Figure 1 that the
30 beam of radiation will successively impinge upon the test
solution contained in the various test cells 14. Because
of the alignment between the outcoming beam of radiation
and the detector 30, the detector 30 wi~.l receive the
output radiation exiting fronl the same test cell 14 into
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which the b~am has been clirected. In oth~r words, ~,~hen
the bcam lS direct,ecl at test: cell 3~, l,he detect.or 30
will be in pos.ition -to receive output racli~tl,on from test
cell 34. Consequently, as thc beam of radi,a-tion :i,s
5 rotated about the central axis 18 of the ~pparatus 10, a
beam of radi.ation will be successively directed ~t each
of the test samples supported in the anrlular array, and
the detector 30 will in t~rn receive output radiation
from the corresponding test samples on whirh the radia-
10 tion has been directed. In this manner, it can b~appreciated that a multitude of test samples may be
quickly and effieiently analyzed.
In the preferred embodiment, the radiation
directing means 20 comprises a mirror 36 arranyed along
15 the eentral axis 18 of the apparatus 10 to recei.ve a beam
of radiation along the central axis 18 and r~direct t~e
beam radially outward towards the tes-t cel].s 14 and
deteetcr 3u. In or~e:- t-~ d-~le~ t;-r~ be~ of r~ iGIl
successively at the various annularly arranc3ed test
20 cells 14, the mirror 36 or other direeti,ng means is
rotated about the central axis 18. A suitable lens 3~ may
be also employed for focusing and eoneentrating the beam
of radiation at the test cells 14. Preferabl,y, the
lens 38 is fixedly mounted with respect to the reflectirlg
25 mirror 36 and also rotates there~Ji.th.
Referring now -to Figures 2-5 w}-ich illust,rate a
preferred embodiment of the present invelltion, the
apparatus 10 ineludes a suitable base melllber 40 whicl
houses the souree 42 of radiation and on which is
30 supported the test cell support rneans 1~. The test cell
support means 12 includes a ~ower circul~r plat:e 4~. ancl
an upper annular plate 46 fi~edly suppcrt,ed toclether in
coaxial alignment by Ineanx of a series of posts ~.P,
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arranged abo~t t,he circumfercnce of the ~.o~ler and upper
plates 44, 46. The upper annular suppori- plate ~t6 in turn
supports an annular test cell assenlbly 5C) ~hich includes
an annular array of test cells or chambers 14 therein.
5 More particularly, the test cell assembly 50 includes
inner anci outer spaced cylindrical ring sections 52, 54
- interconnected by a series of radial wall sections 56
circumferentially spaced about the inner and outer
cylindrical ring sections 52, 54, the inner and outer
lO cylindrical ring sections 52, 54 and radial wall
section 56 together defining the plurality of test cells
or chambers 14. As best seen in Figures 2 and 3, the test
cells l~ are arranged in an annular array. The tops of
each of the test cells 14 are opened for insertion and
15 removal of the fluid containers 16, and the bottoms are
closed by a suitable plate member 58. Each of the tes
cells 14 is of a rectangular cross sectional configura-
tion and is adapted to receive a corresponding shaped
fluid container 16 into which the sample solutions to be
20 tested will be introduced. The test cell assembly 50 is
suitably supported about the inner annular edge of ~he
upper support plate ~6 by suitable fasteners 60, such as
for example screws.
The inner and outer cylindrical ring
25 sections 52, 54 each include a- series of passageways or
apertures 22, 24 communicating with the i.nterior of the
test cells 14, the passageway 22 in the inner cylindrical
ring section 52 being radially aligned with the passage-
way 2~ in the outer cylindrical ring section 5~ so that a
30 beam of radiation directed radially outward from the
central axis l~ and at the same elevation as the-passage-
ways 22, 24 will pass tl-rouyh the passageway 22 in the
inner cylindrical ring section 52 thro~gh the cell l~t and
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exit. t,heref`rom through the corresponcli.ny passacJeway 2~. in
the ou~er cylindrlc~ll ring sect:iorl 5~. T~e fluid
containers ]6 for being received in each o~ the test
cells 14 may either be constructed of a clear, light
5 trallsmittiny material or may tlave suitable light transmit-
ting windows therein for -the passage of radiation into
and out of the fluid containers 16.
The test cell assembly 50 also carries and
supports the radiation directing device 20 for rotation
10 about the central axis 18 of the apparatus 10. More
particularly, the test cell assembly 50 includes a down-
wardly depending support ring 62 which earries at its
inner annular edge suitable bearings 64 for rotatably
supporting a eylindrical support housing 66. The support
15 housing 66 is of a generally hollow construetion and
supports at its upper end a hollo~ tubular ~ember 68 to
which a refleeting mirror 36 is mounted at an angle to
receive a beam of radiation along the axis 18 of the
apparatus 10 and to redireet same radially outward in a
20 generally horizontal direetion. ~ore particularly in this
regard, the hollow tubular member 68 ineludes an inelined
upper end to whieh a eover plate 70 is mounted. The
ref]eeting mirror 36 in turn is supported by the lower
inelined surface of the eover member 70. Also, the
2~ mirror 36 is located so that the beam of radiation
redirected thereby will be at the same axial elevation as
the optical passageways 22, 24 in the test cell
assembly 50. An optieal eondensing lens 38 is suitably
mountecl in the side of the hollow tubular member 68 for
~,0 focusi.ng and concentratincJ the beam of radiation
redirected by the reflecting mirror 36.
A radially extending support arm 32 is suitably
connec-t.ed to the side of the eylindrieal support
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housil,g 66 an~ ext~ncls r~]ial~y outwar~ b(-r,ea~h l:he t,est
cell assernbl~ 50. 'r'he support arm 7,2 in ~urn carries a
suitable radiation detector 30 at its outer end. The
radiation detector 30 includes a suitable radiation
5 receiving aperture (not shown) arranged at an elevation
- corresponding to the elevation at which the beam of
radiation exits from the optical lens 3~. A]so, the radia-
tion detector 30 is supported from the support arm 32 so
that the radiation receiving aperture thereof is circum-
10 ferentially located in alignment with the beanl ofradiation which exits from the optical lens 38.
Accordingly, since the test cell passage~ays 22, 24 are
at the same elevation as the beam of radiation redirected
by the mirror 36, when the support housing 66 is rotated
15 in its bearing 64, the beam of radiation exiting from the
optical lens 38 will be directed radially outward and
pass successively through the te,st cell passageways 22,
24 of each of the test cells 14, with output radiation
exiting from the outer passageways 24 in turn being
20 received by the radiation detector 30.
The cylindrical support housing 66 also
includes a gear ring 72 mounted thereto directly below
the position at which the support arm 32 is mounted
thereto. A motor 74 and drive gear 76 is supported by the
25 lower support plate 44 of the apparatus 10 for driving a
chain 78 entrained about the drive gear 76 and gear
ring 72. As best seen in Figure 5, as the drive gear 76
is rotated, it will rotate the support housing 66 about
the central axis 18 of the apparatus lO, which in turn
30 will cause the directing device 20, the support arln 32,
and the radiation detector 30 to rotate about the central
axis 18 of the apparatus lO. Of course, it will be
appreciated that other suitable dl-ive arrarlgell~en.:s could
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bc provided ror rotating the direct,ing d~v:ice 20, the
support arm 3~, anc] radiation detector 30, such as for
exarllpLe be1t drive systems, direct gear driven systems,
etc. The drive motor 74 can be controlled in any conven-
5 tional manner to in turn control the speed and timing ofro-tat:ion of the directing device 20, the support arm 32
and the radiation detector 30. For example, the motor may
be driven continuously, in which case the directing
device 20 and detector 30 will continuously rotate about
10 the central axis 18 of the apparatus 10, or may be driven
intermittently to index the directing device 20 and
detector 30 from one test cell 14 to the next, etc.
A second hollow tube 80 is secured to the lower
end of the support housing 66 for rotation therewith. The
15 lower end of the second hollow tube 80 passes downwardly
through a central aperture 82 provided in the lower
support plate 44. In the preferred embodiment, electrical
leads 84 for powering the detector 30 and for tran'smit-
ting electronic information from the detector 30 pass
20 radially inward along the support arm 32 and downwardly
through the central aperture 82 in the lower support
plate 44. Excess electrical leads (not shown) are
provided beneath the lower support plate 44 so as to
provide a wire-wrap mechanism while the directing
25 device 20, support arm 32 and radiation detector 30
rotate. In this regard the amount of excess leads is
sufficient to permit the detector 30 to complete at least
one revolution about the test cells 14. With this type of
arrangement, it will thus be appreciated that movement of
30 the detector 30 must be reversed and the detector 30
returned to its initia] start position after the
electrical leads 84 have wrapped around the lower
tube 80. ~owever, it will also be appreciated that such a
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wire-~Jrap arrangement can he avoided by the use of a slip
away assembly, sli.ding electrical contacts or otl~er known
electrical transmission devices for mal~ing electrical
connections between stationary portions of an apparatus
5 and rotating portions~
The electrical output from the detector
device 30 is transmitted to a suitable readout or display
device 86 for displaying the readings made of the various
test samples. Of course, it will be appreciated that such
10 readout or display device 8h may include a central proces--
sor unit for processing the electrical output and
providing different sets of readings and information
respecting the test samples based upon the readings of
the detector 30. The display device 86 and the types of
15 information generated as a result of the radiation
received by the detecting device 30 form no part of the
present invention, and therefore a description of same
will not be presented. In this regard, it is noted
however that such devices and types of information
20 generated with the information from the detector
device 30 are well known to persons skilled in the art.
In order to provide a beam of racdiation for
impingement upon the tcst samples 14, a suitable
source 42 of radiation is provided for transmitting a
25 beam of light along the axis 18 of rotation of the
directing device 20. A sui-table system in this regard is
shown schematically in Figure 3 housed within the lo~er
support housing 40 of the apparatus 10. A suitable light
source 88 is provided which when energi~ed directs radia-
30 tion onto a mirror 90 which in turn reflects the li~htthrough an aperture 92 onto a defractiorl grating 94. 'rhe
defraction grating 94 is rotatable so as t.o provicte an
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essen~:ialiy ,mollocllronl~ltic bearn of radiatic,n of a desi.red
wavelength, clependinc, upon the nature of the l,est
samples, the properties of the test samples to be
measured, etc. Generally, the ~avelength of the radiation
5 will lie in the visible and ultraviole~ ligh1- ranges,
although lower and higher ~avelength rad:iation may be
used in connection with some types of spectroscopic
analysis. From the defrac~ion cJrating 9~t, the beam of
essentially monochromatic light is directed onto a
10 mirror 96 which in turn transrnits the beam of radiation
axially upward along the axis 18 of the apparatus 10. The
beam of radiation is received and reflected by the
rr.irror 36 located on the directing device 20 and
redirected radially outward through the optical lens 38.
15 It will be appreciated that since the beam of monochro-
matic radiation from the radiation source is directed
along the axis 18 of rotation of the directing device 20
and since the mirror 36 of the directing device 20 is
also located along the axis 18, rotation of the directing
20 device 2b will not affect transmission of the radiation;
the directing device 20 will still receive the radiation
and direet same radially outward during rotation. The
radiation source 42 schematically shown in Figure 4 is of
a conventional construction and well known in the art,
25 and only constitutes a schematic representation of a
suitable source of radiation. Of course, depending upon
the properties of the test sarnples being analyzed and the
type of spectroscopic analysis to be made, other types of
radiation sources may be utilizied. The only requirement
30 in aecordance with the preferreci embodiment is that the
beam of radiation be directed along the axis 18 of
rotation of the radiation directing device 20.
The apparatus 10 in accordclrlce with the present
inventiorl i.s par~.ic~llar].y useful in connectioll with
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corlducting spectroscopic arla.Lysis of t ecjt sa~ les whose
properties are constal~ltly varying. For eY~alllplc ,:~len
concentration type ana~ysis is being performed such as
for example in connection with dissolution testing the
5 concentration leve]s of particular samples vlill vary over
- time. In order to evaluate such changes in concen~ration
it is desirable to continuously or per.iodically test the
various solut:ions ov~r time. This rnay be easily
accomplished with the apparatus 10 of the present inven-
10 tion which provides for stationarily supporting the testcells 14. More particularly in accordance with the pre-
ferred embodiment the fluid containers 16 received
within each of the test cells 14 includes a pair of fluid
conduits 17a 17b coupled thereto which are connected
15 respectively to the source of samplc fluid and to an
output device or drain. A test solution is continuously
pumped .nto and then withdrawn from each fluid con-
tainers 16 mourted in the test cells 14. ~ecause the test
cells 14 are stationary with respect to the directing
20 device 20 and radiation detector ~o problems in intro-
ducing and withdrawing fluid from the tcst cells 14 are
minimized since the lines 17a 17b may simply be attached
to the stationary test cells 14. Consequently a
relatively large number of test cells 14 may be provided
25 in the apparatus 10. In the embodiment shown in the
figures the number of test cells annularly suppolted by
the support means 12 is on the order of 50. Of course
larger numbers of test cells 1~ or few test cells 14
could be provided if desired.
As is well known the type of radiation
detector 30 utilized must be compa~ible ~ith the radia-
tion soure 42 being uti~iæed in conneclion with the
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spectroscopic ana]ysis. In other wol-ds, th~re m~st he a
matching bet~eerl the radic~tion detectol- 30 and the
radiation source ~2, althou~h a number of different radia-
tion detectors can be utilized with respect to a number
5 of different types of sources. In the embodimen-ts shown
and described hereinabove, the radiation source ~2 may
comprise the radiation source component of a ~litachi
lodel 100-20 single beam spectrophotomeler, and the
radiation detector device 30 may comprise the detector
lO component of the same Hitachi Model 100-20 machine.
Generally, suitable radiation detector devices which may
be used in connection with conducting concentration
measurements include photomultiplier tubes, solid state
photodiodes, and vacuum photodiodes. Of course, it will
15 be appreciated that when other types of spectroscopic
ana]ysis are to be performed with respect to test
samples, other types oi detector devices may be employed.
~ lso, in the preferred embodiment, a suitable
sensing device 98, such as for example an LED optical
20 pick-up is provided for sensing when the radiation
detector device 30 is in a reference or "0'~ position. The
sensing device 98 is mounted adjacent the location of the
rnotor 74, and a suitable flag 99 for activating the
sensor device 98 is secured to the radiation detector
25 device 30. When the flag 99 passes the sensing
device 98, a signal will be generated to stop the
motor 74 to thereby stop rotation of the directing
device 20 and detector 30. Such sensing devices 98 for
use in precise positioning of moving elements or compo-
30 nents are well known, and therefore the operation andcontrol thereof need not be described in detail. In the
present apparatus, the sensing device 98 may be used in
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connectioll with poslt:ionin~ of the d]rec~ 3 device 20,
supporl arm 32 and radiation detector 30 for conduc-t;-in(J a
new set o~ spectroscop-ic analysis and/or for unwlindirlg o~
the electrical leads 8~ from the hollo~ tuhe 80. Furt}ler,
5 the sensing device 98 may be useful in connection ~Jith
repeatinc~ certain specificd measurements or analysis of
selected cells 1~ by providinc3 a reference or start posi-
tion. Still furth--r, conven~ional techniques for the
control of the position of the radiation detector
10 device 30 and directing device 20, the speed of rotation,
etc. may be eMployed. For example, when continuous
measurements are to be made, i.e., when the detector 30
and the directing device 20 are being rotated on a
continuous basis, suitable controls may be provided for
15 determining at which points or positions meaningful infor-
mation is being received, i.e., at what point in time the
beam of radiation is being directed onto t.he varjo~s test
cells 14. In this regard, the accuracy of the detector
device 30 and the speed of processing (i.e., the rate at
20 which the detector 30 may receive and process informa-
tion) will govern the rate at which sarnples may be
analyzed. However, with the present day equipment, it is
possible to achieve accurate readings of the test samples
at scanning speeds on the order of one cell per second.
As noted above, although the prefel-red
embodiment of the present invention is directed for use
in connection with obtaining concentrat;ion meas~lrements
of fluid test samples, the apparatus 10 i5 equally
applicable for use in connection with other absorption,
30 transmission, and excitation measurselllents in the
analytical chemistry field whel-e the main cost in the
equipment i.s in the source ~.2 and the c~etec~or ~0, and
~2~S~
-lC3-
not in t-.he .sarmpLec thenlselves. ~ith the apparatus ].0 of
the pr~--sent lnvention multiple test samples ca-n be
measured rapidlY and effi.ciently with the same scanning
and detector apparatus. This is particularly importan-t
5 with respect to systems for spectroscopically analyzing
test samples in which fast chemical reactions take place
and/or test samples in flow through test cells where the
properties of the test samples rapldly change.
Accordingly it is seen that in accordance with
10 the present invention there is provided an apparatus 10
for use in spectroscopically analyzing properties of a
plurality of test samples. Support means 12 are provided
for stationarily supportinc~ a plurality of test cells 14
containing test samples to be analyzed and radiation
15 directing means 20 are provided for directing a beam of
radiation towards the suppo-rt means 12. Radiation
detector means 30 are also provided for reeeiving radia-
tion output from the support means 12 the radiation
detector means 30 and radiation direeting means 20 being
20 mounted by mounting means 32 in fixed relationship to one
another. The rnounting means 32 is arranged with respect
to the support means 12 so that when a beam of radiation
from the radiation directing means 20 is direeted at one
of the test cells 14 the radiation detector means 30
25 will receive output radiation from the sarne test cell 14.
Moving means 72 7~ 76 7~ are provided for moving the
mounting means 32 so as to sueeessively direet the beam
of radiation from the radiation direeting means 20 at the
plurality of test cells 1~ so that the radi.ation
30 detecting means 30 will suecessively receive output radia-
tion from the plurality of test cells 14. In the pre-
ferred ernbodin~ent the test cells 1~ i.nclude fluid
containers l6 havin~ input and output fluid conduits 17a
17b coup~ecl theretc) for the continuous introduction and
~S withc.rclwal of test so1utions.
~2~S~:48,
-- ~o--
~ lhilc the preferred embodirnc~rlt. o~ the pre~ent
inveotion has becn shown and describcd, it will be under-
s~ood that such is rnerely illus~rative arld that changes
may be rnade without departing form the scope o~ the
5 invention as claimed.
