JPH02276927A - Integral spectroscope and on-line spectral measuring instrument - Google Patents

Abstract

PURPOSE:To use the integral spectroscope and spectral measuring instrument even under severe environmental conditions like the actual site of a manufacture line without difficult maintenance by uniting a light guide-in part and a spectral part whose plane shape is a Rowland circle by using a material which is high in optical spatial homogeneity. CONSTITUTION:A sample of the manufacture line flows in a measurement cell 20. The luminous flux emitted by a light source lamp 18 is transmitted through a condenser lens 8 to reach a filter 14 and an entrance slit 12. Then the luminous flux which is made incident on the spectral part 6 from the slit 12 is dispersed by a concave diffraction grating 10 to form an entrance slit image at a position corresponding to an exit slit. The incidence end surface of an optical fiber 16 is arranged at the position, so monochromatic luminous flux guided by the optical fiber 16 is transmitted through the sample flowing in the measurement cell part 20, guided by an optical fiber 26 to a detector 30, and detected.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a spectrometer for a spectrophotometer and an online spectrometer suitable for use, for example, in a production line of a chemical plant.

(Prior Art) A spectrophotometer is equipped with a spectrometer to select a wavelength. The spectrometer is equipped with a dispersive element and has an entrance slit and an exit slit at predetermined positions. To prevent dust and corrosive gases from entering the spectrometer, it is filled with a purge gas such as air or nitrogen to isolate it from the outside air.

Spectrophotometers are used for analysis on production lines in chemical plants. To measure a sample on the production line, either take the sample from the I2 production line and place it in the sample chamber of a general-purpose spectrophotometer installed in the measurement room, or set up a bypass flow path on the production line. A flow cell is connected to the bypass channel, and the spectrophotometer is installed so that the flow cell is installed in the sample chamber of the spectrophotometer.

(Problem to be solved by the invention) When measuring a sample on a production line, take out the sample and
If the measurement is carried out in a 1 g chamber, there is a risk that the sample may change in quality, for example due to temperature changes while the sample is being delivered to the measurement chamber. Another problem is that it takes a long time for measurement.

The method of providing a bypass flow path in the production line requires extra maintenance work and is likely to cause safety problems.

Further, even if a bypass flow path is provided, a spectrophotometer must be installed at the manufacturing line site. Manufacturing line sites generally have more severe environmental conditions than measurement rooms; for example, they are not air-conditioned like measurement rooms, may be exposed to rain and wind, and may not be at normal temperature or pressure. Conventional spectrophotometer spectrometers are difficult to maintain when used under such harsh conditions.

In an online spectrometer, a sample solution flows through a measurement cell. Dirt gradually accumulates on the inner wall of the measurement cell, that is, on the window plate through which the measurement light passes.

Therefore, if the measurement cell is used for a long period of time, the measured value of the sample absorbance becomes inaccurate.

Therefore, in order to check the degree of dirt on the measurement cell part,
It is sufficient to flow the standard solution into the measurement cell, but replacing the entire flow path related to the main pipe through which the sample flows with the standard solution requires extensive operations.

The present invention can be used not only in a controlled environment such as a measurement room.
The object of the present invention is to provide a spectrometer that can be used without difficult maintenance even under severe environmental conditions such as on a production line.

It is also an object of the present invention to provide a spectroscopic measurement device suitable for on-line use.

A further object of the present invention is to provide an online spectrometer capable of checking the degree of contamination of a measurement cell.

(Means for Solving the Problems) The spectrometer of the present invention achieves the above-mentioned objectives regarding the spectrometer by filling and integrating most of the material with a material having high optical spatial homogeneity.

The light introducing part that takes in the light from the light source and the spectroscopic part whose planar shape forms a Rowland circle are made of a material with high optical spatial homogeneity, and the relative positions of each other are shifted with almost no space between them. A condensing lens is formed by processing the outer surface of the light introduction part, a dispersion element is formed by processing the outer surface of the light splitting part, and a dispersion element is formed on the Rowland circle between the condensation lens and the dispersion element. is provided with an entrance slit.

A material with high optical spatial homogeneity is a transparent material such as quartz glass or optical glass. Measurement range is ultraviolet, visible,
When measuring a wide wavelength range such as near-infrared and infrared, quartz glass is preferable, and when measuring in the visible and near-infrared ranges, optical glass may be used.

The online spectrometer of the present invention includes the above-mentioned integrated spectrometer, a photodetector, a flow cell for feeding a sample solution, a light flux from the integrated spectrometer to the flow cell, and a light flux transmitted through the flow cell. and an optical fiber that guides the light to the photodetector.

Furthermore, in order to check the degree of contamination of the measurement cell, the online spectrometer of the present invention is equipped with a switching flow path that switches between a sample solution and a standard solution and sends them to the flow cell.

(Function) Since the interior of the spectrometer is almost entirely filled with a material with high optical spatial homogeneity, dust and corrosive gases do not enter.

Furthermore, the relative positions of the dispersion element and the inlet slit are fixed, and no adjustment is required due to changes in temperature or the like.

Online spectroscopic measurement equipment equipped with an integrated spectrometer
The light beam from the integrated spectrometer is guided to a flow cell through an optical fiber, and the light beam that has passed through the flow cell is guided through an optical fiber to a photodetector for detection.

The switching channel sends a sample solution to the flow cell during measurement, and sends a standard solution to the flow cell when monitoring the degree of contamination.

(Embodiment) FIG. 1 shows an embodiment in which the present invention is applied to, for example, an online spectrophotometer for a production line of a chemical plant.

2 is a spectrometer of the present invention, which includes a light introduction part 4 and a spectroscopic part 6.
are integrally formed of optical glass such as BK7.

The light introduction portion 4 is formed into a block shape, and a part of the light entrance surface thereof is processed into a convex curved surface outward and polished to form a condenser lens 8.

The spectroscopic section 6 is formed in a cylindrical shape, and a concave diffraction grating 10 is formed by cutting grooves on a convex spherical surface on a part of the side surface of the cylinder. The concave diffraction grating 10 is formed so that the cylindrical circle is a Rowland circle.

An entrance slit 12 is fitted on the Rowland circle on the line connecting the condenser lens 8 and the concave diffraction grating 10, and a filter 14 is fitted near the entrance slit 12 on the light incident side. The entrance slit 12 and the filter 14 are fitted into a narrow gap cut in the optical glass forming the spectrometer.

The input end face of the bundled optical fiber 16 is optically joined to the position corresponding to the exit slit on the Rowland circle of the spectroscopic section 6 .

18 is a light source lamp.

Reference numeral 20 denotes a flow cell section provided in a pipe of a production line of a chemical plant, and the measurement light is transmitted through lenses 22 and 24, forming a measurement cell section. lens 22
．． Reference numeral 24 is provided to allow the light beam emitted from the optical fiber 16 to pass through the sample without wasting it, and to make it enter the end face of the optical fiber 26. A monochromatic light beam guided from the spectrometer 2 is guided to a lens 22 of a measurement cell section 20 by an optical fiber 16. A light-receiving bundle type optical fiber 26 is provided sandwiching the measurement cell section 20 so as to face the output end face of the optical fiber 16, and the light beam emitted from the output end face of the optical fiber 26 is photoelectron-intensified by a condenser lens 28. The detector 30 is installed so that the light is incident on the light receiving surface of the detector 30, such as a multiplier tube.

The operation of this embodiment will be explained.

A sample on the production line is flowing inside the J1q constant cell section 20. The light beam emitted from the light source lamp 18 passes through the condenser lens 8 and reaches the filter 14 and the entrance slit 12. The light beam entering the spectroscopic section 6 from the entrance slit 12 is dispersed by the concave diffraction grating 10, and forms an entrance slit image at the position corresponding to the exit slit. Since the incident end face of the optical fiber 16 is arranged at that position, the monochromatic light beam guided by the optical fiber 16 passes through the sample flowing inside the measurement cell section 20, and is guided by the optical fiber 26 to the detector 30 for detection. be done.

FIG. 2 shows the embodiment of FIG. 1 in which the measurement method is a double beam method.

Although not shown, it is assumed that the same spectrometer as that in FIG. 1 is used. Bundled optical fiber 16
is equally divided into a sample side portion 16a and a control side portion 16b. A chopper 34 rotated by a motor 32 is provided to separate the light beams emitted from the optical fibers 16a and 16b into a sample side and a contrast side, respectively.

The same sample cell section 20 as shown in FIG. 1 is provided on the sample side, and a lens 3 is provided on the contrast side to guide the light beam to the receiving optical fiber.
6.38 is provided. Bundled optical fibers 26a, 2 are installed to receive the light beams on the sample side and the control side, respectively.
6b are installed, and both merge into the bundle type optical fiber 26.

As in FIG. 1, 28 is a condenser lens, and 30 is a detector.

In the case of FIG. 2, in addition to the measurement cell section 20, a motor 32, a chopper 34. Optical fiber 16 a + 16 b t 26 a * 26
It is convenient to assemble it as one unit including b.

The measurement cell section 20 can also be used as a reflective type. However, in the case of a reflective type, the optical path length is twice the gap through which the sample flows.

As in the embodiments shown in Figures 1 and 2, online use is possible by connecting the exit slit corresponding position to the sample measurement point with the optical fiber 16, and connecting the sample measurement point to the detector with the optical fiber 26. becomes even easier.

FIG. 3 shows an embodiment in which switching of the entrance slit and wavelength scanning can be performed.

The entrance slit 12a is switched by a motor 13 for operating the entrance slit. A cut with a minute gap is provided in the optical glass of the spectrometer 2 in the part where the entrance slit 12a is provided, and the slit 12a is formed within the gap of the cut.
can be moved.

Further, in FIG. 3, the input end face of the optical fiber 16 is supported so as to be movable along a Rowland circle corresponding to the exit slit position of the spectroscopic section 6 in order to perform wavelength scanning. When the wavelength scanning range becomes wider, the filter 14 is switched simultaneously with the movement of the optical fiber 16 using a mechanism similar to that of the slit 12a.

In order to provide a gap in which the slit 12a can move, the third
As shown by the broken line in the figure, the light introduction part 4 and the spectroscopic part 6
are configured separately, and the image areas 4 and 6 are separated with a smaller gap.
may be fixed.

In order to perform wavelength scanning in FIG. 3, instead of scanning the optical fiber 16, the optical fiber 16 is fixed, and the spectrometer main body 2 and the light source 18 are rotated about the center O of the spectroscopic section 6. You can also do this.

In the online spectrophotometer shown in FIG. 1 or 2, a sample solution constantly flows through the measurement cell section 2o. Dirt gradually accumulates on the inner wall of the measurement cell section 20, that is, on the window plate through which the measurement light passes. Therefore, if the measurement cell section 20 is used for a long period of time, the measured value of the sample absorbance becomes inaccurate. Therefore, in order to check the degree of contamination of the measurement cell section 20, it is sufficient to flow the standard solution into the measurement cell section 20, but if we replace all the flow paths related to the main pipe through which the sample flows with the standard solution, Large-scale operations are required.

Figure 4 is '6+l! This figure shows an example of a measurement cell section that is equipped with a switching channel that can switch between a sample solution and a standard solution to check the degree of contamination in the constant cell section.

Reference numeral 40 denotes a flow cell in the measurement cell section, which is used in the sample cell section 20 in FIG. An input end of an optical fiber 26a that approaches the other gti 44 of the flow cell 40 and guides the light transmitted through the flow cell 40 to a detector is provided.

A pipe 46 for transporting the sample solution and a pipe 4B for transporting the standard solution (or sample blank solution) are connected to the flow cell 40 so as to join together, and the pipe 46 is provided with an on-off valve 50 . is provided with an on-off valve 52. The on-off valves 50 and 52 are controlled by electrical signals sent from the main body of the measuring device so that one is open and the other is closed.

In the measurement cell section of FIG. 4, the sample solution is normally ii! 1
At regular time, the on-off valve 50 on the sample solution side is opened, the on-off valve 52 on the standard solution side is set in the closed state, and the optical fiber 16a is connected to the integrated spectrometer as shown in FIG. 1 or 3.
A light beam for sample measurement is sent into the flow cell 40 to measure the absorbance.

After the sample solution has been allowed to flow for a certain period of time, the on-off valve 50 on the sample solution side is closed, the on-off valve 52 on the standard solution side is switched to open, and the standard solution is allowed to flow into the flow cell 40. At this time, the degree of dirt inside the cell, that is, on the inner wall surfaces of the window panels 42 and 44, is measured, and the data is stored in a computer that controls the operation of the main body of the measuring device.

Next, the on-off valve 5o is opened again, the on-off valve 52 is returned to the closed sample solution measurement state, and the absorbance of the sample solution is measured. The previous data on the degree of contamination inside the cell was subtracted from the measured data, and if the obtained data differed by more than a certain value from the raw data obtained by simply measuring the sample solution, the degree of contamination was corrected. Use this data as the correct data for absorbance measurement.

The switching flow path shown in FIG. 4 is shown in more detail in FIG.

The sample solution is passed through the pipe 46 from the on-off valve 50 to the flow cell 4o.
It passes through the on-off valve 51 and flows out. On the other hand, the standard solution flows through the circulation channel formed by the pipe 48. That is, the standard solution is transferred from the standard solution storage MJ56 to the circulation pump 5.
8 through the pipe 48, passes through the on-off valve 52, passes through the flow cell 40, passes through the on-off valve 53, and returns to the standard solution storage tank 56 again.

Control signal A is supplied from the measuring device main body to the on-off valves 50.51, control signal B is supplied from the measuring device main body to the on-off valves 52.53, and control signal C is supplied from the measuring device main body to the circulation pump 58. be done.

In the operation mode for measuring the absorbance of a sample solution, the control signal A is turned on and the on-off valves 50 and 51 are opened, the control signal B is turned off and the on-off valves 52 and 53 are closed, and the control signal C is also turned on. The circulation pump 58 is in an off state and is stopped.

On the other hand, in the operation mode for monitoring the degree of dirt inside the flow cell 40, the control signal A is in the OFF state and the on-off valve 5 is in the OFF state.
0.51 is closed, control signal B is on, and on-off valve 5
2.53 is opened, the control signal C is turned on, and the circulation pump 58 is put into operation.

FIG. 6 shows a measurement cell portion of the online spectrometer shown in FIG. 2, in which a flow cell 60 is also provided on the control side, and a standard solution is constantly supplied to the flow cell 60.

A sample solution and a standard solution are alternately supplied to the flow cell 40 on the sample side by switching the on-off valves 50 and 52, and a standard solution is constantly supplied to the flow cell 60 on the control side from the standard solution pipe 48. Similar to the flow path shown in FIG. 5, the flow path of the pipe 48 is a circulation flow path in which the standard solution is supplied from the standard solution storage tank by a circulation pump and returns to the standard solution storage tank again.

The light beam from the spectroscope is split into a sample side optical fiber 16a and a contrast side optical fiber 16b, the sample side light beam is guided to the flow cell 40, and the contrast side light beam is guided to the flow cell 60. The light flux that exits the flow cell 40 is guided to the optical fiber 26a, and the light flux that exits the flow cell 60 is guided to the optical fiber 26b, joins the optical fiber 26, and is guided to the photodetector.

In FIG. 6, when measuring a sample solution, the control signal A from the measuring device main body is turned on, and the on-off valve 50 is opened.
The control signal B is turned off and the on-off valve 52 is closed.

On the other hand, when monitoring the degree of contamination of the flow cell 40,
When the control signal A is turned off, the on-off valve 50 is closed, and when the control signal B is turned on, the on-off valve 52 is opened.

FIG. 7 shows another example of a spectrometer for oscillation, which is equipped with a control side optical system for measuring a standard solution in order to obtain a baseline absorbance.

Reference numeral 64 denotes a measurement cell section, in which a cell chamber 69 is formed between window plates 66 and 68 made of quartz glass or the like. A sample solution flows through the cell chamber 69. The space between the window plates 66 and 68 in the cell chamber 69 forms a predetermined optical path length. Light receiving side optical fiber 26 on the sample side
a is fixed to the measurement cell part 64 with a screw so that its tip end surface is positioned close to the window plate 68 in the measurement cell part 64.

Irradiation side optical fiber 1 that guides light from the spectrometer in the measurement device main body
The distal end surface of the optical fiber 6 is placed at a position facing the distal end surface of the light-receiving optical fiber 26a across the cell chamber 69.

A condensing lens 62 is provided between the optical fiber 16 and the cell chamber 69, which condenses the light beam emitted from the distal end surface of the optical fiber 16 and transmits it through the cell chamber 69. Focus on the surface.

A square cell 4 is provided to accommodate a standard solution for obtaining a baseline absorbance. optical fiber 16
A plane mirror 70 is inserted between the condenser lens 62 and the cell chamber 69 in order to guide the light beam emitted from the condenser lens 62 and condensed by the condenser lens 62 to each sample cell on the sample side or the control side. is attached to the rotating shaft of the percussion motor 72, and has two positions, as shown by the broken line, to reflect the light that has passed through the condenser lens 62 to the target side, and a position to deviate from the optical path and reflect the light to the sample side, as shown by the solid line. Can be moved between threading positions. Optical fiber on receiving side of contrast side/<26
The tip end face of b is positioned so that the light beam reflected by the plane mirror 70 is focused. The square self-container 4 is provided on the optical path that is reflected by the plane mirror 70 and guided to the optical fiber 26b. This square self-container 4 is a fixed type, that is, a non-flow type, and is easily replaceable. The optical path length of the square cell 4 is the cell chamber 69 on the sample side.
is set equal to the optical path length of If a standard solution is placed in the square cell 4, the light beam transmitted through the standard solution can be received by the optical fiber 26b and taken into the main body of the measuring device to obtain a baseline of absorbance.

A stepping motor is used as the active motor 72 in order to correctly determine the rotational angle position. Although not shown in the figure, means for detecting the origin position of the rotation angle is also provided. The light-receiving side optical fibers 26a and 26b join into a bundle of optical fibers 26 from the middle, and the other end of the optical fiber 26 is guided into the main body of the measuring device.

A control signal for the active motor 72 is given from the main body of the measuring device.

The square selfie 4 used in FIG. 7 is shown in FIG.

In the embodiment shown in FIG. 7, a sample solution is poured into the sample-side cell chamber 69, and half a solution is placed in the rectangular self-container 4. The light separated by the spectrometer in the measurement device is sent to optical fiber 1.
6, and the motor 72 switches the plane mirror 7o to the position shown by the solid line or the position shown by the broken line. At the position indicated by the solid line, the light passes through the sample solution in the cell chamber 69 and enters the optical fiber 26a, and the absorbance due to the sample solution is measured. When the plane mirror 70 is switched to the position indicated by the broken line, the light is directed to the square I'! ! The light passes through the solution and enters the control optical fiber 26b, and the baseline absorbance is measured.

In FIG. 7, as means for switching the position of the plane mirror 7o, for example, a solenoid may be used instead of a motor.

If a non-flow type rectangular cell 4 is used as a control cell, it becomes easier to check the baseline using a standard solution. Furthermore, by using the square selfie 4, the standard solution can be easily exchanged depending on the sample to be measured, making it possible to perform absorbance measurements that are consistent with the actual situation on the plant line. However, a flow cell may also be used on the control side.

Furthermore, as shown in FIG. 4 or 6, a standard solution can be flowed into the cell chamber 69 on the sample side instead of a sample solution, so that the degree of dirt on the window plates 66 and 68 can be checked. You can also do this.

It is convenient to assemble the portion surrounded by broken lines in FIG. 7 as one unit.

FIG. 9 represents an embodiment with another means of dividing the light from the optical fiber 16 into a sample side and a control side.

A semi-transparent mirror 76 is used in place of the plane mirror 70 in FIG. The light emitted from the optical fiber 16 and passed through the condenser lens 62 is always divided into two by the semi-transparent mirror 76. The light transmitted through the semi-transparent mirror 76 passes through the sample-side cell 8 and enters the optical fiber 26a, and the light reflected by the semi-transparent mirror 76 passes through the contrast-side cell 80 and enters the optical fiber 26b.

Since light is always incident on the optical fibers 26a and 26b, in order to guide either one of the lights to the main body of the measuring device, the optical fiber 26a is used.

26b are provided with optical switching elements 82 and 84, respectively. 86 is an optical multiplexer, and optical switching element 8
2.84, the lights are collected and connected to the optical fiber 26.
It leads to the main body of the measuring device.

A control signal is sent to the optical switching elements 82 and 84 from the measuring device main body, and the optical switching elements 82 and 84 are turned on and off.
By controlling off, the absorbance of the sample solution can be measured or the baseline can be checked using a standard solution.

The cell 8.80 may be a flow cell.

It may also be a non-flow type rectangular cell. Further, when the sample side self 8 is a flow cell, it may be possible to switch between the sample solution and the standard solution as shown in FIG. 4 or FIG. 6.

(Effects of the Invention) In the present invention, since the spectrometer is almost integrated with a material having high optical spatial homogeneity, the spectrometer is shielded from outside air and dust, eliminating the need for adjustment and inspection. Maintenance becomes easier. Furthermore, the number of processing and assembly steps and the number of parts are reduced, making it possible to lower costs.

By being isolated from outside air and dust, there is no need for air or nitrogen purging devices, which were previously required.

A spectrophotometer using the spectrometer of the present invention can be used even under harsh environmental conditions, so it can be used online in a field such as a production line of a chemical plant.

By providing a switching channel in the flow cell of the measurement cell section that can switch between sample solution and standard solution,
When constantly measuring the absorbance of sample solutions on the production line over a long period of time, it is possible to monitor the degree of contamination caused by the sample solution itself in the flow cell at arbitrary time intervals, and it is possible to correct the absorbance as necessary. become.

[Brief explanation of drawings]

Fig. 1 is a schematic plan view showing an online spectrophotometer using a spectrometer of one embodiment, Fig. 2 is a schematic plan view showing the detector part from the sample measurement part in another usage mode, and Fig. 3 is FIG. 4 is a schematic plan view showing another embodiment of the spectrometer, FIG. 4 is a flow path diagram showing the measurement cell section in the embodiment of the measuring device, FIG. FIG. 6 is a flow path diagram showing a measurement cell section in yet another embodiment of the measuring device, FIG. 7 is a schematic plan view showing yet another embodiment of the measuring device, and FIG. 8 is a square diagram used in FIG. 7. FIG. 9 is a perspective view showing the cell, and a schematic plan view showing another embodiment of the measuring device. 2... Spectrometer main body, 4... Light introduction part, 6... Spectroscopic part, 8... Condensing lens, 10... Concave diffraction grating, 12, 12a...
...Inlet slit, 14...Filter, 16
．． 16a, 16b, 26, 26a. 26b... Optical fiber, 18... Light source lamp, 20.64... Measurement cell section, 30...
...Detector, 40°69...Flow cell,
46... Sample solution pipe, 48...
Standard solution pipe, 50, 51, 52゜53...
・Opening/closing valve, 7o...Flat mirror, 74...
Square cell, 76...Semi-transparent mirror, 78,80...
····cell. Test liquid↓ Patent Demonroku Shimadzu Corporation

Claims (3)

[Claims] (1) The light introducing part that takes in light from the light source and the spectroscopic part whose planar shape forms a Roland circle are made of a material with high optical spatial homogeneity, and are mutually adjacent to each other with almost no space between them. The relative positions are fixed, a condensing lens is formed by processing the outer surface of the light introducing section, a dispersion element is formed by processing the outer surface of the spectroscopic section, and the distance between the condensing lens and the dispersion element is An integrated spectrometer with an entrance slit on the Rowland circle. (2) The light introduction part that takes in light from the light source and the spectroscopic part whose planar shape forms a Rowland circle are made of a material with high optical spatial homogeneity, and are mutually adjacent to each other with almost no space between them. The relative positions are fixed, a condensing lens is formed by processing the outer surface of the light introducing section, a dispersion element is formed by processing the outer surface of the spectroscopic section, and the distance between the condensing lens and the dispersion element is An integrated spectrometer with an entrance slit on the Rowland circle, a photodetector,
An online spectroscopic measurement device comprising a flow cell for feeding a sample solution, and an optical fiber for guiding a light beam from the integrated spectrometer to the flow cell and guiding a light beam transmitted through the flow cell to a photodetector. (3) The online spectrometer according to claim 2, wherein the flow cell is provided with a switching channel that switches between a sample solution and a standard solution and sends them to the flow cell.