ON-LINE OPTICAL ANALYSIS OF A SUBSTANCE THROUGH A CONDUIT SECTION OF A PROCESS LINE

ANALYSE OPTIQUE EN LIGNE D'UNE SUBSTANCE A TRAVERS UNE SECTION DE CONDUITE D'UNE LIGNE DE PROCESSUS

English Abstract

A conduit-mounted light-transmitting device (10) for allowing optical analysis
of a substance through a process line conduit (14) made of a light-
transmitting material. The device (10) comprises a clip (24) adapted to be
detachably secured about the conduit section. The clip (24) defines an optical
path intersecting the conduit section when the clip (24) is mounted thereon.

French Abstract

La présente invention concerne un dispositif de transmission lumineuse (10) monté sur une conduite et conçu pour permettre une analyse optique d'une substance à travers une conduite (14) de ligne de processus constituée d'un matériau transmettant la lumière. Ce dispositif (10) comprend un clip (24) conçu pour être fixé de manière amovible autour de la section de la conduite. Ce clip (24) définit un trajet optique qui coupe la section de la conduite lorsque le clip (24) est monté sur cette dernière.

Claims

CLAIMS:
1. A non-intrusive device for allowing spectrum analysis of a confined
process stream through a light-transmitting conduit section of a process line,
comprising a clip adapted to be externally mounted on the light-transmitting
conduit
section, the clip having a substantially hollow body defining a slot for
allowing
mounting of the hollow body on the light-transmitting conduit section, the
slot being
bounded by sidewalls, means for allowing light to pass through said sidewalls,
an
input fiber optic cable connectable to said clip and having a light delivery
end
disposed outside of the conduit section on a first side thereof for directing
a beam of
light from a source of light through said sidewalls and a wall of the conduit
section
and transversally through the confined process stream flowing through the
conduit
section, an output fiber optic cable connectable to said clip and having a
receiving
end disposed outside of the conduit section for transmitting light emanating
from the
wall of the conduit section to a light-receiving sensor, and wherein the
hollow body
of the clip houses at least one optical element, the optical element focussing
the light
transmitted across the conduit section and the wall thereof into the output
fiber optic
cable, the optical element being disposed on a second side of the conduit
opposite
said first side between an outer surface of the conduit section and the
receiving end of
the output fiber optic cable.
2. A non-intrusive device as defined in claim 1, wherein said clip is
adapted to be releasably secured about the light-transmitting conduit section.
3. A non-intrusive device as defined in claim 1, wherein said clip is
adjustable so as to be securable on light-transmitting conduits having
different cross-
sectional dimensions.
4. A non-intrusive device as defined in claim 1, wherein the slot is
configured for receiving interchangeable conduit adapters adapted to grip
conduits of
different external diameters.
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5. A non-intrusive device as defined in claim 4, wherein said
clip further
includes a removable cover for maintaining a selected one of said
interchangeable
conduit adapters captive in said peripheral slot.
6. A non-intrusive device as defined in claim 1, wherein said
sidewalls
are made of a light-transmitting material, thereby providing said means for
allowing
light to pass through said sidewalls.
7. A non-intrusive device as defined in claim 6, wherein said
body has a
first connector adapted to be connected to the input fiber optic cable to
direct the
beam of light through said slot and through the light-transmitting conduit
section on
which the clip is mounted, and wherein said at least one optical element
comprises a
lens.
8. A non-intrusive device as defined in claim 7, wherein said
body has a
second connector adapted to be connected to a light-receiving sensor for
receiving the
light emanating from the process stream through the light-transmitting conduit
and
the slot of the clip.
9. A non-intrusive device as defined in claim 8, wherein said
second
connector is connectable to said light-receiving sensor via the output fiber
optic
cable.
1 0 . A non-intrusive device as defined in claim 1, wherein said
means
comprises a pair of opposed light transmitting windows in said sidewalls and
defining an optical path for receiving and conducting the beam of light
through the
light-transmitting conduit section of the process line.
1 1. A non-intrusive device as defined in claim 10, wherein a
conduit
adapter is removably installed in said slot, said conduit adapter having a
base wall
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from which extends a pair of spaced-apart conduit gripping arms adapted to
receive
therebetween the light-transmitting conduit section, wherein said conduit
adapter is at
least partly made of a light-transmitting material.
12. A conduit-mounted light-transmitting device in combination
with a
light-transmitting conduit section mounted in a process line for allowing
optical
analysis of a substance in the process line, the conduit-mounted light-
transmitting
device comprising a clip detachably securable about the conduit section, said
clip
defining an optical path intersecting the conduit section when said clip is
secured
thereabout, wherein said clip has a substantially hollow body defining a slot
having a
conduit engaging section by which said body is releasably mounted directly on
the
light-transmitting conduit section, said optical path extending through
sidewalls of
the slot for receiving and conducting a beam of light through the light-
transmitting
conduit section, and at least one optical element housed within said body for
collecting the light transmitted through the conduit section, said optical
element
focussing the light transmitted through a wall of the conduit section into an
output
fiber optic cable removably coupled to the clip via a connector provided on
said
body, the optical element being disposed externally of the light transmitting
conduit
section between an outer surface of the light transmitting conduit section and
the
output fiber optic cable.
13. A combination as defined in claim 12, wherein said conduit
engaging
section includes an open ended slot defined in one face of the body, and a
conduit
adapter removably installed in said open ended slot, said conduit adapter
having a
base wall from which extends a pair of spaced-apart conduit gripping arms for
receiving therebetween the light-transmitting conduit section, wherein said
conduit
adapter is partly made of a light-transmitting material.
14. A combination as defined on claim 12, wherein said body has
a first
connector adapted to be connected to an input fiber optic cable to direct a
beam of
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light through said conduit engaging section and tffi-ough the light-
transmitting conduit
section on which the clip is mounted.
15. A combination as defined in claim 12, wherein light-transmitting
material is selected from a group consisting of: near infrared transmitting
material
and infrared transmitting material.
16. A combination as defined in claim 14, said conduit engaging
section is
made of a light-transmitting material.
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Description

CA 02463851 2004-04-16
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ON-LINE OPTICAL ANALYSIS OF A SUBSTANCE THROUGH A
CONDUIT SECTION OF A PROCESS LINE
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention generally relates to spectroscopy and, more
particularly, to a non-intrusive device for allowing spectrum analysis of a
substance through a conduit section of a process line of a given processing
plant.
Description of the Prior Art
It is known to carry out spectroscopy for monitoring the chemical
composition and physical properties of various solutions used in processing
plants, such as chemical, pharmaceutical, petroleum, semiconductors and food
product processing industries. Typically, such a spectrum analysis is
performed
by extracting a sample of the substance to be analyzed from the process line
of
the processing plant and carrying out a spectrometric analysis of the
collected
sample by passing near to far infrared radiation therethrough.
Instead of the above-mentioned method, it would be preferable to
perform the test on-line directly through a conduit section of the process
line, and
if the process line includes a conduit section made of a light-transmitting
material
directly through this existing conduit section, to avoid process line
modifications.
SUMMARY OF THE INVENTION
It is therefore an aim of the present invention to provide a light-
transmitting device adapted to be mounted on a processing line externally of a
conduit section thereof for allowing spectrum analysis of a substance
circulated
through the conduit section.
It is also an aim of the present invention to provide for on-line
analysis of a substance without having to extract a sample of the substance
from
the process line through which the substance is circulated.
It is a further aim of the present invention to provide a light-
transmitting device for allowing spectrum analysis of a substance circulated
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through a process line without having to modify the process line when the
latter
includes a conduit section made of a light-transmitting material.
Therefore, in accordance with the present invention, there is
provided a non-intrusive device fox allowing spectrum analysis of a confined
process stream through a light-transmitting conduit section of a process line,
comprising a clip adapted to be externally mounted on the light-transmitting
conduit section, said clip being at least partly made of a light-transmitting
material and connectable to a source of Iight to direct a beam of light
transversally through the conduit section.
The expression spectrum analysis is herein intended to mean the
investigation of substances or bodies by means of their electromagnetic
spectra,
specifically chemical composition and physical properties analysis thereof.
The expression light is herein intended to mean all wavelengths
included in the electromagnetic spectrum, including the ultraviolet, visible
and
infrared portions of the electromagnetic spectrum.
W accordance with a further general aspect of the present
invention, there is provided a conduit-mounted light-transmitting device for
allowing optical analysis of a substance through a conduit section of a
process
Line, wherein said conduit section is made of a light-transmitting material,
the
conduit-mounted light-transmitting device comprising a clip adapted to be
detachably secured about the conduit section, said clip defining an optical
path
intersecting the conduit section when said clip is secured thereabout.
BRIEF DESCRIPTION OF THE DRAWllVGS
Having thus generally described the nature of, the invention,
reference will now be made to the accompanying drawings, showing by way of
illustration a preferred embodiment thereof, and in which:
Fig. 1 is a schematic perspective view of a process line upon
which a light-transmitting device in accordance with the present invention is
externally mounted for allowing spectrum analysis of a process stream through
the process line tubing;
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Fig. 2 is an enlarged view of the light-transmitting device mounted
on a section of the process line;
Fig. 3 is an enlarged partly exploded view of the light-transmitting
device illustrating how the device is removably secured about a section of the
process line; and
Fig. 4 is a cross-sectional view of the light-transmitting device
mounted on the process line.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention, as will be explained hereinafter, is
generally directed to a light-transmitting device 10 adapted to be removably
secured about a process line of a given processing plant to permit optical
analysis
of the composition and/or physical properties of a substance circulated
through
the process line. More specifically, the light-transmitting device 10 is
adapted to
be externally mounted on a conduit section of an existing process line to
direct a
light beam (visible near infrared or infrared) from a remote light source (not
shown), through the conduit section and then carry the light emerging from the
illuminated substance through the conduit section to a light receiving sensor
(not
shown), such as a spectrophotometer. It is understood that the conduit section
of
the process line has to be made of optically transparent or translucent
material
such as polytetrafluoroethylene (PTFE), other fluorinated hydrocarbon
polymers,
and any other light/infrared transmitting material for allowing the light to
pass
transversally therethrough. For instance, the conduit section could be made of
TeflonTM, glass, polypropylene, polystyrene or other polymers.
As will be seen hereinafter the present invention advantageously
allows on-line control and monitoring of a process stream without having to
extract a product sample from the process line. There is thus no risl~ of
contamination of the process stream. The present invention is even more
advantageous in industrial applications comprising a process line including
light-
transmitting conduit sections in that control and monitoring of the process
stream
can be performed by simply installing the light-transmitting device 10 on the
process line externally of a light-transmitting conduit section thereof, that
is
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without having to replace a segment of the process line by a light-
transmitting
conduit section, thereby obviating any process interruption. That is to say
that in
those applications, the process line does not have to be modified in any way.
One
has only to mount the Light-transmitting device 10 externally on a Iight-
transmitting conduit section of the process line.
Fig. 1 exemplifies one possible application of the present
invention. More specifically, Fig. 1 depicts a wet station 12, such as those
found
in semiconductor industries. The wet station 12 essentially comprises a re-
circulation line 14 composed of a bath 16, a filter 18, and a pump 20
connected
IO together in a closed circuit via TeflonTM tubing 22. The bath 16 can
contained
various solutions, such as cleaning, stripping or etching solutions.
As seen in Fig. 1, the light-transmitting device 10 is directly
installed on a selected conduit section of the existing process line 14
externally of
the TefIonTM tubing 22. The light-transmitting device 10 generally comprises a
IS clip 24 adapted to be detachably secured on a variety of conduits or tubes
having
different external diameters.
The clip 24 has a hollow body 26 defining a peripheral open-ended
elongated slot 28 adapted to receive one of a plurality of interchangeable
conduit
adapters, one of which is illustrated at 30 in Fig. 3. A different conduit
adapter is
20 used for each diameter of conduit, thereby allowing the body 26 to be
mounted on
a wide variety of conduits. The conduit adapter 30,includes a pair of spaced-
apart
conduit gripping arms 32 extending perpendicularly from a base wall 33 for
' tightly grasping a conduit or tube having an external diameter slightly
greater than
the spacing between the gripping arms 32. At least the base wall 33 of the
adapter
25 30 is made of a light-transmitting material, such as but not Limited to
PTFE or
other fluorinated hydrocarbon polymers. Once the right adapter has been chosen
and fitted over the selected conduit section of the process line 14, the body
26 is
brought over the adapter 30 to locate the same within the slot 28 in the body
26.
The adapter 30 is retained captive in the slot 28 by a cover plate 34. The
cover
30 plate 34 is removably secured to the body 26 by means of screws 36. The
cover
plate 34 is provided on an undersurface thereof with an elongated locking rib
38
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for engagement between a pair of axially spaced-apart locking fingers 40
extending laterally outwardly from one of the gripping arms 32 of the conduit
adapter 30 to lock the latter against axial sliding movement in the slot 28.
As shown in Fig. 4, the body 26 is provided on one side of the slot
28 thereof with a first connector 41 for receiving the distal end portion of a
first
fiber optic cable 42. The first fiber optic cable 42 is connected at an
opposed
proximal end thereof to a light source (not shown) for directing a light beam,
such
as but not limited to an infrared beam (IR beam) or a near infrared beam (NIR
beam), transversally through the conduit section of the TeflonTM tubing 22 of
the
process line 14. The sidewalls of the slot 28 can be made of a light-
transmitting
material for allowing the light beam to pass therethrough or, alternatively a
pair
of opposed aligned light-transmitting windows 44 could be formed therein. The
windows 44 could be provided in the form of holes. The light beam is directed
so
as to perpendicularly intersect the central axis of the' conduit section on
which the
clip 24 is mounted.
According to the illustrated embodiment of the present invention,
the Iight that emerges from the illuminated process solution through the
conduit
section of the TeflonTM tubing 22, the base wall 33 of the conduit adapter 30
and
one of the sidewalk of the slot 28 is diverted 180 degrees by a pair of flat
mirrors
46 (see Fig. 4) before being transmitted to alight receiving sensor via a
second
fiber optic cable 48 connected at a distal end portion thereof to the body 26
of the
clip 24 by a second connector 50. According to one embodiment of the present
invention, the flat mirrors 46 are mounted within the hollow body 26 of the
clip
24 by means of an aluminum frame (not shown). It is noted that a lens could
also
be provided to focus the transmitted light into the second fiber optic cable
48 or,
alternatively, directly into the light receiving sensor. Furthermore, it is
noted that
the second connector 50 could be disposed on a side of the slot 28 opposite
the
first connector and in alignment therewith. In fact, a variety of optical
elements
could be integrated within the hollow body 26 of the clip 24 to cause the
light to
follow various optical paths between the light source and the light-receiving
sensor.
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According to an embodiment of the present invention, the hollow
body 26 of the clip 24 is made of TeflonTM to protect the optical elements
housed
therein from a corrosive surrounding environment. However, it is understood
that
the clip 24 could be made out of a wide variety of materials.
In the case of a tubing 22 made of non optically transparent or
translucent material, a section of such tubing could be replaced once by an
appropriate conduit section, and then the light-transmitting device 10 could
be
used, when required, thereon, i.e. without further changes to the tubing of
the
process line.
As can be appreciated from the foregoing, the present invention
allows for on-line spectnun measurement for determiung the chemical
composition andlor properties of a substance through an existing conduit
section
in which the substance is circulated.
It is easily seen that the present invention as described above has
many advantages that can be summarized as follows: no sample preparation,
rapid installation with no process interruption, totally non-contact, non-
intrusive
for no possibility of contamination, etc.
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Representative Drawing