JPH05503359A - A method for measuring the concentration of a material, an apparatus for implementing the same, an application of the measuring method to a method for changing the concentration of a material contained in a fluid, and its configuration - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] nothing Method for measuring the concentration of materials, equipment for performing the method, and method for changing the concentration of materials contained in/in fluids Application of the above measurement method to and its configuration The present invention is directed to ) Changing the concentration of at least one material contained in the fluid described in the generic concept and included in the fluid described in the nineteenth general concept of claim 19. Involves the use of a method of varying the concentration of at least one material.

When passing light through a partially transparent medium, the intensity of the transmitted ray is equal to the medium, Depends on the material mixed into the medium and the frequency of the light beam. These frequencies From the attenuation value depending on In the case of a material, the concentration of the material within the medium can be measured.

This type of material concentration measurement method is described in German Patent Application No. 25, 25. It is well known from No. 375. This well-known method involves The light beam of the conductor diode is emitted through the measuring medium and detected. in the measuring medium To determine the concentration of the gaseous component to be detected, the emission is measured between the maximum and minimum absorption values. The emission wavelength is switched periodically. intermediate frequency of the light beam emitted by the diode lies on the slope of the absorption line, an alternating current signal is received by the detector and this A signal is sent to a phase sensor whose output signal directly indicates the gas content in the measuring medium. will be the value.

In German Patent Application No. 37 41 026, such material concentration is also mentioned. The method of measuring the degree of oxidation is well known. In this method, the laser beam is is switched, but one of the resonance frequencies is the maximum absorption value of the gas to be detected. and the other resonant frequency is the absorption minimum. Attenuation situation of the strength of both resonant frequencies The concentration of the gas being charged can be derived from The intensity value of each passing ray is Stored in the sample and hold circuit. Value stored in sample and hold circuit is processed using an arithmetic circuit in each measurement cycle.

U.S. Patent No. 3,804,535 also describes this method of measuring material concentration. It is well known. In this case, a light source is used that emits light with two different frequencies. light is emitted through the measuring medium containing the gas whose concentration is to be measured. . The amplifier for detecting the light that passes through it is capable of emitting light at any light frequency. Only the open signal that is received is driven open, thereby reducing signal interference in the received signal.

In the present invention, new signal processing is handled as described in the claims. In this process, the concentration of the material contained in the measurement medium is measured using at least two methods. Performed using different light frequencies. The aforementioned method, its usage, and method The equipment used for the implementation must contain at least one material that has a high degree of reliability regarding signal interference. The problem of changing the concentration of liquids, especially reducing the content of harmful substances in liquids, is resolved.

The method of the present invention, the device of the present invention, its general purpose, and the amount of water contained in the liquid are described below. See the drawing for an example of a configuration for varying the concentration of one material. I will explain in detail. The drawings are as follows.

FIG. 1 is a block circuit diagram of an apparatus for carrying out concentration measurements.

FIG. 2 shows the frequency f of the light beam sent out from the transmitter of the same device.

and r2 indicate the temporal succession of alternating pulsed light beams.

Figure 3 shows the light beam shown in Figure 3 after passing through a comparative bowl of the measuring medium or device. Schematically shows temporal continuity.

Figure 4 is a block circuit diagram of the signal evaluation circuit of the concentration measuring device, and Figure 6 is the signal evaluation circuit. The time after passing through the integrator of the signal evaluation circuit shown in Figure 3 after passing through the bandpass of Idealize and show the continuity.

FIG. 8 shows the low frequency part of the frequency spectrum of successive pulses.

Figure 9 shows a device for measuring the concentration of materials containing harmful substances in diesel engine exhaust gas. , a light emitter 3, and a plurality of small measuring bowls 5a.

0.5z, a light beam if unit 11, a detector I3, and a detector 15. , the plurality of measurement small bowls 5a0. . 5z is related to the light beam emitted from the light emitter 3. contain comparison media whose absorption values and concentrations have already been determined, and each containing Partially transparent mirrors 7a, . . . , 7z and light detectors 9a, .

9Z, and this light detector converts the received light beam into an electrical signal in proportion to its intensity. On the other hand, the beam splitter 11 divides the light beam output from the light emitter 3 into the measuring medium 1 and into the small measuring bowl. 5a, , 5z, and the detector 13 measures the intensity of the light beam passing through the measuring medium It is converted into a light signal and emitted from the light emitter 3 on the detector 15, and the comparative small bowls 5a,...5 A portion of the light beam that has passed through neither z nor the measuring medium 1 is received. Detector 9a, 9 z, 13 and 15 are all connected through wirings 17a, , 17z, 19 and 20. and is connected to signal evaluation circuits 21, 22, and 23.

The signal evaluation circuits 21, 22 and 23 are connected to a judgment circuit 25, which Confirm the concentration value of the material contained in the measurement medium 1. For signal wiring, draw a solid line in Figure 1. The path of the ray is shown as a dotted line. The determination device 25 increases the output. It is connected to the width switch 26 and is explained in the embodiment below and shown in the block circuit diagram of FIG. As shown in the figure, the exhaust gas of internal combustion engines, especially diesel engines51, contains harmful substances. Data and settings can be changed to reduce the amount. In an internal combustion engine, the engine Gin is energy that can be mechanically used by burning chemically synthesized energy. Convert it to Rugi. Known embodiments include diesel engines; These include Otto engines, jet propulsion engines, and gas turbines.

The light emitter 3 is connected to a control device 27 that includes an energy supply 29 and a driver 30. It is connected. The driver 30 is a timer, and the light emitter 3 controls the frequency f1 and pulses of different light beams with f2 and f2 at the same repetition frequency 17T, 4 and constant The energy supply source 29 is controlled so that the energy is delivered at a pulse interval Tr. Pulse interval For Tr, from the beginning of one pulse to the next with a ray with another ray frequency. Interpret it as the temporal interval to the beginning of the pulse. Furthermore, the driver 30 processes measured values. It is synchronously connected to the determination circuit 25. As shown in FIG. A pulsed beam of beam frequency f and f2 is fired with a pulse duration d.

The pulse interval between pulses having the same beam frequency f or f2 is TN. continuous The pulse intervals T a of the pulses that appear alternately are set to be the same length, and the pulse This corresponds to half the length of the space interval T. What is noteworthy about frequency is that every The switching frequency of the pulse is doubled, and the switching frequency of the pulse of light beam frequency 2 or f2 is doubled. It is the same as the switching frequency. The pulse with optical frequency f1 is light A pulse of line frequency r2 exists between the two. Regarding the pulse of light frequency f2 analog is applied.

Known harmful substances contained in the measurement medium 1 and in the comparison small bowl 5a at known concentrations When measuring the concentration of a substance, the light frequency f that is within the range of the known absorption maximum of the substance , is emitted from the emitter 3 with a pulse width d. different light emitters The adjustment of the beam frequencies f1 and f2 in No. 3 will be explained below. ray f 1 passes through the measuring medium 1, its intensity is measured by the detector 13, and the electrical A typical measurement signal is sent to the signal evaluation circuit 22. Partially transparent mirror 7a Other parts of the ray ``1'' fall on the other partially transparent mirrors, excluding 7z. Then, the light beam is split again here.

A portion of the light ray f1 passes through the comparative small bowl 5a. The intensity of the transmitted light is measured by the detector 9a. Then, the electrical measurement signal is further sent to the signal evaluation circuit 21 . The rest of the ray f1 The signal reaches the detector 15 and is further sent to the signal evaluation circuit 23.

The emitter 3 then switches to produce a pulse of pulse width d with a beam of beam frequency f2. is the frequency f mentioned above in analog form.

is emitted in the same way as , but this ray of frequency f2 is completely absorbed by known materials. Not collected. The above steps are repeated exactly.

As shown in FIG. 2, a constant and identical pulse continuous frequency 1/T At t, a pulse with a constant pulse height is emitted, but at that time, a pulse with a beam frequency f, A pulse with a beam frequency f2, followed by a pulse with a beam frequency f2, is emitted alternately.　Light ray frequency f , the intensity of the pulses is weakened by the material in the measurement medium 1 or the comparative small bowl 5a, and the light The intensity of the pulse with the linear frequency f2 hardly weakens when it is detected by the detectors 13a to 9a. The light is received by. The sequence of pulses after leaving the emitter 3 is measured by the detector 15. According to the above, it is as shown in Fig. 2. The sequence of pulses passing through the measuring medium 1 is According to the measurement by the detector 13, the results are as shown in FIG. Comparison small bowl 5a and measurements The successive pulses passing through the medium 1 are at a distance of W44 from each other. Measured by detector 13 A typical continuous pulse is schematically shown in FIG. A succession of these The pulses differ from each other only in the absolute and relative values of the pulse heights. this pulse The difference in height contains criteria regarding the desired material concentration.

To measure the desired concentration, the signals received by detectors 9a, 13 and 15 are signal evaluation circuits 21, 22 and 23. Ratio of two or more as described below Small bowl 5a0. .

When 5Z is used, a switch (not shown) is provided in front of the signal evaluation circuit 21, and the The signals from the detectors 9a, . . . , 9z of the comparative small bowls 5a, . . . , 5z used selected by the team.

The signal evaluation circuits 21, 22 to 23 are connected to the detectors 9a, 13, etc. as shown in FIG. A preamplifier 33 and a filter are used as a series circuit for the electrical signal sent from the switch 15. -35, time and frequency selection gate circuits 37 and 39, and demodulator 41 have. The time selection gate circuit 37 selects when a pulse is output from the light emitter 3. Passes only signals that are generated at a point and have the same pulse shape as the output pulse. It is controlled by the driver 30 so that the The filter 35 filters the light rays f and and the intermediate frequency corresponding to the reciprocal 1/Ta of the pulse interval Ta in the pulses of f2 and f2. It is configured as a bandpass with

That is, the intermediate frequency of the bandpass 35 is the frequency of the bandpass 35 having a light frequency f or f2. This frequency is twice the pulse continuous frequency of the pulse. Its output signal is an amplitude adjustment signal. The signal is sent to a demodulator 41. The frequency selection gate circuit is located in the middle as a bandpass 39. This intermediate frequency is equal to the frequency in the pulse of the light beam ``, or f2. This corresponds to the inverse number 1/T, l of the pulse interval T8.

The output signal of the band pass 39 is sent to the determination circuit 25. bandpass 35 hand The width is the frequency at which the carrier signal at frequency 1/T-a creates interference along with the used signal at frequency 1/T-. It is set so that it can pass through without causing any damage. A band with intermediate frequency 1/T- The hand width of the path 39 is such that signal changes can pass through without interference due to concentration changes. On the other hand, due to temperature noise in the measuring medium I, dust in the light beam, etc. signal degradation due to momentary interruptions in the measurement medium I, or The measurement signal is influenced by changes in the measurement signal as a result of temperature gradients. It is set not to.

The signal detected by the detector 9a is processed as described above in analog form and Similarly, the demodulator (configured as an analog demodulator 41) It is sent to the constant circuit 25. The difference in the signals sent via the wiring is From the known concentration, the desired concentration in the measuring medium l is obtained.

The electrical signals sent directly to the detector 15 are processed in analog form. Demodulator (ana The signal demodulated by the log-format demodulator 41) is Ideally, it is a DC voltage signal of height. However, the ray frequencies f1 and f Frequently the pulse heights of pulses with 2 are not generated with the same pulse height Therefore, we decided to fold these demodulated signals using two demodulated signals. By reshaping different pulse heights of pulses with different beam frequencies f, and f2, can be achieved. The signal from the detector 15 is also used to monitor the output of the light emitter 3. Ru.

The pulses received by the detectors 9a and 13 can be viewed with an oscilloscope, for example. As you can see, the image changes rapidly.

This ends the role of the optical frequencies fl and f2 in the electrical signal. these The frequency of , described below, is again used to confirm the different pulses transmitted. Ru. If you connect a frequency analyzer instead of an oscilloscope, high frequencies can be detected continuously. Next to this, a switching frequency 1/T7 appears based on the pulse shape, but this frequency is the time interval between pulses of the first and second rays fl and f2 that are alternately successive. This switching frequency value 1 corresponds to the reciprocal of Ta, and as shown in FIG. /TT corresponds to two frequency values on the left and right side, and these correspond to the switching frequency value 1/T A, the sum of the alternating successive rays f and the reciprocal of the temporal interval TN of f2, and Corresponds to the difference between Here, if the material concentration in the measurement medium 1 or the comparative small bowl changes, For example, depending on the instantaneous concentration, the frequency values 1/TT+1/TN and 1/TT The amplitude height of l/TN also changes. At this time, the pulse from the light emitter 3 is as described above. If the pulses are emitted with the same interval as shown in the figure, the frequency value 1/Ty The magnitude of 1/TN is halved, and the frequency value 1/T7 is also the same, that is, this The value is 1/T8. of the bandpass 35 and the bandpass 39 after the demodulator 41. The use results in measurements with little noise and interference.

The obtained concentration value is stored within the determination circuit 25 over an adjustable time width. Even if the measurement signal disappears for a short time as described above, the control described below It is also possible to calculate the values via the device 71.

Configuration consisting of small bowls 5a, 5z and detectors 9a, 9z, 13 and 15 A unit may consist of independent structural parts or may be integrated into a single block. It may also be cast. In particular, light guides the path of the light beam before and after the small bowls 5a, 5z. If it can be ensured by It can also be integrally formed into a composite unit.

The continuous emission time of the light pulse can be changed, but it must be set in the judgment circuit (25). Must be.

When storing only the concentration value, in order to estimate the desired measurement value in the future, The driving conditions for the configuration described below, such as engine temperature and fuel injection amount, were measured. The information may also be input and stored together with the density value and the like.

If the pulse width d is extremely short with respect to the pulse repetition frequency 1/Tt, the band The intermediate frequency of path 35 is adjusted to an integral multiple of the repetition frequency 1/'rt. pa When the pulse width is short, the bandpass 35 is removed and the demodulator 41 is used to recover the pulse amplitude. You may also use a cooking device.

If the gate circuit 37 is simply used as a "window" that is always open, the pulse When the water is required, it is changed by absorption in the measurement medium or comparison small bowl 5a. The gate circuit 3 is configured in advance according to the curve shape of the pulse to be received. Identification can also be made within 7.

If the determined concentration of the measuring medium 1 is small, the signal picked up by the detector 13 is It may be significantly affected by noise. In this case, the modified circuit shown in Fig. For optimal signal determination, the pulse duration should match the rest period between pulses. will be carried out. The signals from the detectors 9a (, , 9z) and 13 are sent to the amplifier 33 and the amplifier 33. After the evaluation is performed using the filter 35, the circuit'! Sent to A44, but this time The road network consists of four integrators 47 connected in series according to the control information of the driver 30. Send a signal from a to 47d. Integration must not be performed fixedly at the same time; all measurements must be performed. The integration must be done arbitrarily at a given point at the end of the period, but the integration is performed using one integrator and its This can be done using a generator circuit connected to the stomach.

When the integral I or ■2 is outputted, one pulse with rays f1 or f2 is output. It is done while you are there. The following integrals I3 and ■4 are the parameters with rays f and f2. pulse-free periods between pulses and pulses with rays f2 and f. This is done during the non-pulse period in between. When determining the integral value, the determination circuit 25 determines the integral I, The value of the integral I is subtracted from the value of , and the electrical signal thus determined has a ray f2. Zeroed before firing the pulse. Next, from the value of integral I2, the value of integral I4 is drawn, and its signal similarly goes to zero before emitting a pulse with ray f, Set. The continuous pulses determined in this way during the period are shown in Figure 8. is derived from the difference A to the signal of the detector 9a, shown on the abscissa. signal exists The measurement disturbance that occurs during the period when the This appears as a positive step (not shown).

Integration is performed for each pulse, and during the subsequent rest period, the discharge time constant is used to A discharge takes place, the time constant of which is The discharge is carried out so that it passes through the pot 5a and becomes zero again, so that the electricity The reference for concentration is set to occur before being zeroed by the There is.

In the above explanation, only the comparative small bowl 5a containing a known material at a known concentration is used. It is used. Instead of one small bowl 5a, each one has a different material in a known concentration. You may also use two small bowls. Depending on the material concentration to be measured, the light beam of the emitter 3 partially, a corresponding partially translucent mirror 1. .

7Z is used to emit light to pass through the corresponding small bowls, . . . , 5z.

Emits at least two narrow beams of light with one repetition frequency in the kilohertz band. The light emitting device 3 includes a diode laser 1, a dye material laser, and a CO□ laser. A laser device such as a spectral lamp binary covered by a rotating impeller is suitable. Ru. These laser devices are tuned to two different frequencies and their activation state pulsed by a current, and then emitted at any desired resonant frequency. For example, a grind or a resonant mirror may be adjusted between the pulses to It is. It also uses lamps to create filters that are separated from each other by bands of opacity. An impeller having a rotor may be rotated.

The transmission curve of the filter is set similarly to that described above.

The rotation speed of the filter impeller and the number of filter segments are determined by The switching frequency is set to correspond to the intermediate frequency of the bandpass filter 35.

Frequently used words in which the absorption wavelengths of the material whose concentration in the measurement medium 1 is to be measured are close to each other. The absorption bandwidth is often narrow. Fine tuning of rays f and f2 The setting is such that the light beam of emitter 3 passes through the corresponding comparison bowl filled with the corresponding material. of the emitter 3 until there is a ray within or outside the bandwidth that emits light and is absorbed. This is achieved by varying the frequency f, to f2. Also, the frequency that should be set is It is also possible to configure the wave numbers f and f2 to be automatically observed.

As the light emitter 3, a laser device, especially a solid state laser, a dye material laser, a CO2 When using a laser, the beam splitting mirror 11 is not used, but a resonant mirror is used instead. The laser beam advances into the measuring medium l by a small bowl compared by another resonant mirror. Another laser beam may be emitted as shown in step 5.

The narrower the pulse width d you select, the more the gate circuit 37 can transmit the signal for later processing. The "receiving window" for sending out data can also be set smaller. This causes jamming pulses and erroneous Information is reduced.

Instead of performing concentration measurements using light absorption in measurement medium 1 and comparison bowl, light The diffusion of In this case, from the measurement medium or the comparative small bowl to the original To measure the intensity of the diffused light beam, the detector 13 is placed next to the emitter 3 and the detector 9 a, . . . , 9z are constructed before the comparison small bowls 5a, . . . , 5z.

Compared to the emitted pulse shape, the pulse shape of the pulse diffused toward the source is "dirty". '', and the pulse travel time passing through the measurement medium l and comparison small bowls 5a, 5z. In the above measurement method, as long as d is shorter than the pulse width d of the emitted pulse. must take this contamination into account. By determining the light rays that diffuse towards the source, the flow medium The concentration of particles in the body can be determined.

A filter whose passband is tuned to the corresponding pulse repetition frequency. interference by using a detector and by interpreting the measurement signal as a modulated signal. High reliability can be obtained regardless of the signal.

When changing materials chemically, especially harmful substances that degrade the environment, When changing into a new bond or component, the concentration of that bond or component changes in a short time. When they appear together, a reagent is often used for the chemical change, and the reagent itself is is also harmful to the environment. Therefore, it is necessary to prevent these materials from changing.

Accurate and timely measurement by continuously measuring the exact amount of material to be changed instantaneously Reagents can be mixed in precisely metered amounts; however, such reagents may Those that are not added after a period of time or are added only at a specified concentration It is.

Determine the amount of material or reagent by measuring the exact amount of material to be changed. After the amount has passed through the reaction zone, it can be subjected to subsequent processing with or without concentration measurements. Reagents are loaded so that only the amount of material or reagent is introduced into the reaction zone. amount is set.

This method is not only suitable for measuring materials that are harmful to the environment, but also allows for precise dosing of materials. Manufacturing and processing of highly sensitive products in the chemical industry that require the use of materials and reagents It has also been passed through scientific processing.

The methods already described are suitable for carrying out this chemical method.

Integrally forms a device for measuring the concentration of a material contained in at least one of the fluids mentioned above. Regarding the configuration incorporated in the nitrogen system of the diesel engine 51 as an internal combustion engine, The explanation will be given below using exhaust gas as an example. In this example, nitrogen oxide NO and nitrogen dioxide NO, are harmful substances in the exhaust gas of diesel engines51. will be reduced. This configuration is shown in the block circuit diagram of FIG. exhaust gas is engine After exiting 51, it flows past a particle filter 53 (not required).

Subsequently, the exhaust gas is detected by a sensor in the engine control circuit 59 provided in the exhaust gas pipe 55. 57, the sensor determines the pressure in the exhaust gas pipe 55, for example. This is to control the turbocharger according to the measured pressure. Sensor 5 A reaction zone 61 is provided downstream of 7, and the reaction zone is surrounded by a broken line in FIG. It is shown in A fresh air supply 63 and ammonia supply are provided in the reaction zone 61. A feeding device 63 is inserted. A catalyst 67 is connected to the reaction zone 61, It continues to the concentration measuring section 69. For engines whose exhaust gas temperature exceeds 1000"C In this case, no catalyst may be used. Concentration measuring section 69, fresh air and ammonia The supply units 63 and 65 of A and the engine control circuit 59 are one control system. 71. The control device 71 includes the numerical storage device described above. A supply unit 63 is installed in the storage device according to the engine data. The data for setting 65 and 65 are organized, and the engine data is For example, the temperature, rotation speed, and fresh air amount measuring device 75 connected to the engine control circuit 59 The intake of fresh air is determined by the engine control circuit 59 at the injection nozzle 7. The amount of fuel to be injected is controlled by 7. Control device 71 is connected to output amplifier 26 has been done. The value measured by the concentration measuring section 69 is stored in the numerical storage device 73. input in addition to one or more engine data.

When driving the diesel engine 51, as already mentioned, the supply unit 63 and 65, the data input to the storage device 73 and the concentration measurement unit 69 Ammonia and fresh air are introduced into the reaction zone 61 according to the data measured at Supplied. According to the chemical equation below, the nitrogen oxide NO and NO contained in the exhaust gas are and nitrogen dioxide N Ox in the catalyst 67 as 4NO+4NH, +O□ --- → 4Nz +6Hz 06NO□±8NH, --1 → 7N2 +12H,.

It is converted into water H, O and nitrogen N2. If the exhaust gas temperature exceeds 1000'C, The chemical reactions described above proceed without a catalyst.

The measuring section 69 measures the exhaust gas after the catalyst 67 using a measuring frequency of 500 Hz. Measure the ammonia content in the gas.

Based on measurements, very little ammonia is released from the exhaust gas into the surrounding environment. In addition, in order to keep the NO and NO□ contents as low as possible, The data set to 3 will be rewritten. Internal combustion after reducing nitrogen oxides Significant reductions in dioxin emissions in institutions will be made.

Data entry into the storage device 73 allows measurement values to be missing for a short period of time, as already explained. It is also possible to estimate the measured value when the object is dropped.

The high-speed measurements made by the present invention are made within seconds and are If the load is changed immediately, the hazardous substance content will be significantly reduced.

Instead of measuring ammonia content, No and/or NOx content can be measured. or other substances depending on the light frequency used. Wear. The content of sulfur dioxide in the exhaust gas, as well as the content of other unwanted substances can also be measured. Increase the number of comparative small bowls 9a to 92 with different materials. For example, even if the absorption curves of individual materials partially overlap, the measurement medium 1 The concentration of these substances within the body can be measured. In this case, measured at different frequencies By identifying the concentration, the concentration is determined.

Instead of filling the comparison bowls with different materials, fill some of the comparison bowls 9a to 92 with the same material. It can also be filled with different concentrations of materials. Do not perform measurements over a large concentration range. This method is recommended if necessary.

Depending on the measured concentration value, adjust the amount of reagent mixed and changing the processing parameters i.e. temperature, pressure, flow rate, etc. Method of the invention can be carried out not only for gases but also for liquids.

In the combustion gas, the NOX content changes depending on the combustion temperature. Diesel In the case of engines, for example, as the output increases, the combustion temperature rises, and as a result, the N The Ox content also increases. Supply unit 63 for fresh air and ammonia and 65 and the time until both reagents appear on the reaction zone 61. After further shortening the immobility time based on the elapsed time in In order to perform the processing, the concentration measurement values that have been measured and entered into the storage device 73 are It is estimated in terms of time taking into consideration the operating time, and from there, the Using the diesel engine drive data configured in Calculate the amount of reagent to be supplied to the reaction zone by the supply units 63 and 65. Ru.

frequency Summary book In this method of measuring the concentration of a material, one side of the light is absorbed in the light absorption band of the material. , the other ray is not absorbed, and the method uses the same pulse repetition frequency and pulse spacing. is also performed using the same pulses. has an intermediate frequency equal to the reciprocal of the pulse interval. The detected signal is filtered using a filter. The density of the material that absorbs light rays The intensity is measured from the amplitude change of the filtered signal.

A filter is used in the apparatus for carrying out the method described above, but the filter The filter bands of are each adjusted according to the pulse repetition frequency generated. Modulation signal By interpreting the measured signal as a signal, high reliability is achieved despite interfering signals. can get.

This device is equipped with a supply device for mixing the above-mentioned materials with reagents that change due to chemical reactions. It has a configuration with The concentration of the material can be varied precisely and reduced to (this configuration This is applied, for example, to the removal of nitrogen from the exhaust gas of internal combustion engines.

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Claims (1)

[Claims] 1. A first light having a first frequency (f1) that is at least within the range of the maximum absorption value line and a second line with a frequency (f2) that deviates from said absorption maximum of the material to be measured. A light beam is emitted so as to pass through the measurement medium (1) containing said material, and said measurement The intensities of said first and second rays after passing through the medium (1) are measured by a detector (13). In the method for measuring the concentration of a material, in which the concentration of the material is converted into a proportional electrical signal, ray frequency The pulse interval between pulses with different numbers (f1, f2) is kept constant. The electrical signal is demodulated, and the concentration of the material is calculated from the amplitude height of the demodulated signal. A method for measuring the concentration of a material. 2. Part of the first and second rays is split, and the split part is small. proceeding through at least one comparative medium (5a,...,52), Each of the comparison media contains a known amount of the material whose concentration is to be measured in the measurement medium (1). to determine the concentration of said material in said measuring medium (1). Therefore, the light rays that passed through the measurement medium and each comparison medium (1, 5a, ..., 52) Claim 1, characterized in that the electrical signals indicating the strength of the Concentration measurement method described. 3. Before or after the electrical signal is temporally demodulated in order to isolate it from interference. Said claim, characterized in that the selection of said electrical signal is carried out on the basis of frequency at The concentration measuring method according to item 1 or 2. 4. A frequency-based selection is made in a frequency band to reduce disturbances in the measurement. In order to reduce the frequency, the intermediate frequencies in this frequency band are Comparable to the line pulse time interval (TN) value, its integral multiple, or its inverse value. 4. A method according to claim 3, characterized in that: 5. A first light having a first frequency (f1) that is at least within the range of the maximum absorption value line and a second line with a frequency (f2) that deviates from said absorption maximum of the material to be measured. A light beam is emitted so as to pass through the measurement medium (1) containing said material, and said measurement The intensities of said first and second rays after passing through the medium (1) are measured by a detector (13). In the method for measuring the concentration of a material, in which the concentration of the material is converted into a proportional electrical signal, and the second ray is emitted alternately as pulses with the same repetition frequency, ray frequency The pulse interval between pulses with different numbers (f1, f2) is kept constant. Part of the first and second rays are split, and the split part is at least one proceeding through two comparative media (5a,...,5z), said comparative media; Each body is mixed with a known amount of the material whose temperature is to be measured in the measurement medium (1). that the measurement medium and each comparative medium (1, 5a, ..., 5z) are that the intensities of the first and second rays passed are integrated over an arbitrary period of time; , the integral values are compared to determine the concentration of the material in the measuring medium. A method for measuring the concentration of a material, characterized by: 6. From the electrical signals of the first and second rays after passing through the narrow band width, The wavenumber band is further processed so that the intermediate frequencies of that frequency band are alternately consecutive. the time interval (TT) value of the pulses of the first and second light beams, or an integer thereof; Claim 1, characterized in that it corresponds to a double value or its reciprocal value. The method according to any one of Item 5. 7. The calculated concentration value is stored for a predetermined period of time. , a method according to any one of claims 1 to 6. 8. characterized in that the concentration of said material is determined during a subsequent time interval of several seconds. The concentration measuring method according to any one of claims 1 to 7. 9. To emit at least two light beams (f1, f2) with different frequencies a second light emitter (3); a control device (27) for controlling the light emitter (3); A light beam that has passed through the measurement medium (1) or been diffused by the measurement medium (1) a detector unit (13) for detecting the intensity of the To carry out the method described in one of paragraphs 1 to 4 or 6 to 8. In the device, the control device (27) has a driver (30), and the control device (27) has a driver (30). The light emitter (3) transmits light beams (f1, f2) with different frequencies within a tolerance range. controlling to emit light alternately at a constant and same repetition frequency (1/TT); The detector unit (9a,..., 9z, 13) includes a demodulator (41) and a determination unit. A device characterized in that a unit (25) is connected. 10. A part of the light beams (f1, f2) of the light emitter (3) is passed through, and the concentration is measured. at least one comparison medium (5a, . . . ) containing a known concentration of the material to be determined; ．． , 5z). 11. The rear side of the detector unit (9a,..., 9z, 13) and the demodulator (41) connected to the front or rear side of the time selection or frequency for said electrical signal; Said claim, characterized in that it comprises gate circuits (37, 39) whose number can be selected. The device according to ranges 9 to 10. 12. The frequency selection gate circuit (39) is a bandpass, and its intermediate frequency The number is the inverse of said time interval (TB) between pulses of the first and second rays in alternating succession. 12. Device according to claim 11, characterized in that it corresponds to a number. 13. Emit at least two light beams (f1, f2) with different frequencies a light emitter (3) for controlling the light emitter (3); and a control device (27) for controlling the light emitter (3). , light passed through the measurement medium (1) or diffused by the measurement medium (1) a detector unit (13) for detecting the intensity of the line. An apparatus for carrying out the method according to one of paragraphs 5 to 8, comprising: The emitter (3) divides the pulses consisting of different light beams (f1, f2) into the same pulses within a tolerance. The control device (27) is used to perform control so that the light is emitted alternately at the same repetition frequency. A driver (30) containing a material whose concentration is to be measured and a light emitting device (3). At least one comparative medium (5a, . . . ．． ．． , 5z) and connected to the rear of the detector unit (9a,..., 9z, 13). at least one connected to each other and switched and connected by said driver (30). The integrator (47a, 47b, 47c, 47d) and the similarly connected determination device (2 5). 14. Connected to the rear side of the detector unit (9a,..., 9z, 13), Before the recording integrator (47a, 47b, 47c, 47d) or the demodulator (41) between the pulses of the first and second light beams (f1, f2) that are connected and successive alternately; Equal to the time interval (TT) value, or its integer multiple, or its reciprocal value characterized by comprising a bandpass filter (35) having an intermediate frequency , an apparatus according to any one of claims 9 to 13. 15. A storage device (73) that stores the calculated concentration value for a predetermined period of time. ), according to any one of claims 9 to 14, characterized in that: The device described. 16. Using the apparatus according to any one of claims 9 to 15, To change the concentration of at least one material in the body, especially a harmful substance. In the configuration, at least one reagent that changes the material by a chemical reaction, Arrangement with a feeding device (63, 65) for mixing the fluid stream into the reaction zone. 17. The measuring medium (69) of the device is directed toward the flow direction of the fluid. be provided at the rear of the reaction zone (61), and that the supply device (63, 65) Supply of the reagent by each according to the concentration of the material measured in the measurement medium (69). a control device (71) connected to said device; The configuration according to claim 16. 18. The supply device (63, 65) is connected to the exhaust gas conduit (55) of the internal combustion engine (51). ) twice, each controlled by said control device (71). (63,65) with ammonia on the one hand and fresh air on the other. is supplied to the combustion gas of the internal combustion engine (51); such that the ammonia or nitrogen oxide concentration is measured continuously over a period of several seconds. Claim 16 or 17, characterized in that the device is formed Equipment described in Section. 19. In the method according to any one of claims 1 to 8, contained in the fluid. application to changes in the concentration of at least one material. 20. At least one reaction parameter or the amount of at least one reagent added is changed based on the concentration calculated in the measurement medium (1). The application according to claim 19, wherein: 21. Claims characterized in that the concentration measurement is carried out in a flowing medium. Applications according to paragraphs 19 or 20. 22. measuring the concentration of one or more substances in the combustion gas; Depending on the concentration, the reaction zone connected upstream of the measurement medium (69) Claims characterized in that at least one amount of reagent material is arranged and added. Application of any of paragraphs 19 to 21. 23. Ammonia is metered and added to the combustion gas of the internal combustion engine in the reaction zone. nitrogen oxides or added ammonia in the measuring medium (69); by measuring the concentration of nitrogen oxides, whether nitrogen oxide emissions are prevented or at least reduced; based on the measured concentration so that the release of ammonia is almost completely prevented. Claim 19, characterized in that the amount of ammonia is optimized by 22.