SU1332153A1 - Photometric analyser - Google Patents

Abstract

The invention relates to the photometry of liquid media and can be used in the chemical, oil refining, food, and other industries, as well as for the protection of the environment. The purpose of the invention is to increase the measurement accuracy. The device introduced additional light sources similar to those used. The special implementation of switching devices allows one to take measurements of radiation from all sources in turn, and further operations carried out in the measuring device make it possible to get a relation from the ignals, (but not excluding the effect of the drift of the characteristics of the photoreceivers , which is especially important for long-term measurements of x. 1, ill. i (L s

Description

one

1332153

The invention relates to photometric analyzers for the composition of liquid media and to be used in chemical, pharmacological, food refining, etc., production facilities, as well as in environmental protection systems and agrochemical service.

The purpose of the invention is to increase the accuracy of measurements, especially with long-term measurements.

The drawing shows a schematic diagram of a photometric analyzer.

The analyzer contains a pulsed power supply unit 1, the first switch 2, the first 3 and second 4 light sources, the first semi-transparent plate 5, the sample cell 6, the second semi-transparent plate 7, the third 8 and fourth 9 light sources, the first 10 and second 11 collectors, the first 12 and 13 second fibers of the first collector, the first 14 and second 15 fibers of the second collector, the first 16 and second 17 photodetectors, a separating device 18, the second switch 19, the first, second, third and fourth memory devices 21 - 23 respectively meter

device 24, synchronization device 25, first, second, third and fourth controlled keys 26–29, respectively, of the first switch, four-channel shift register 30 of the first switch, first, second, third, and fourth controlled keys 31–34, respectively, of the second switch , four-channel shift register 35 of the second switch.

The pulsed power supply unit 1 is connected via the first switch 2 to four light sources. The optical axes on which sources 3 and 4 are mounted are mutually perpendicular. Similarly for sources 8 and 9 of light. At the intersection points, translucent plates 3 and 7 are installed. The light guides 12 and 13 of the first collector 10 are installed behind the corresponding translucent plates on the optical axes of the light sources 4 and 9. The cuvette with sample 6 is mounted on the optical axis of the light source 3. Behind the cuvette 6, the first light guide 14 of the second collector 11 is located. The second light guide 15 is mounted behind the floor

0

five

0

35

40

A transparent plate 7 on the optical axis of the light source 8. The first photodetector 16 and the second photodetector 17 are located behind the first and second collector, respectively.

Photodetectors are connected to a dividing device 18, the output of which is connected via a second switch 19 to memory devices 20 to 23. Measuring device 24 has four inputs to which corresponding memory devices are connected. The synchronization device 25 is connected to the control inputs of the first 2 and second 19 switches, the measuring device 24 and the pulsed power supply unit 1. The control inputs of the keys 26-29 are connected to the corresponding outputs of the four-channel shift register 30 of the first switch 2, and the control inputs of the keys 31-34 of the second switch 19 to the outputs of the four-channel 5 shift register 35. The first 26, second 27, third The 28 and fourth 29 controlled keys of the switch 2 are connected to the first 3, second 4, third 8 and fourth 9 light sources, respectively. The first 31, the second 32, the third 33, and the fourth 34 controlled keys of the switch 19

20-23 are connected to the corresponding devices. The inputs of the switches 2 switches are combined with the output of the switching power supply unit, and the inputs of the switches 19 switches with the output of the dividing device. The control inputs of the switches 2 and 19 are the inputs of the shift registers.

The synchronization device 25 generates a sequence of pulse 0

which goes to the pulsed power supply unit 1, the shift registers 30 and 35, and the measuring device 2.4. Each pulse of the device 25 forms in the pulse power supply unit 1 a corresponding power supply current pulse. Shift register 30 when

The gg of the first pulse closes the key 26 and the current supply pulse arrives at the first light source 3. During the second pulse, the register 30 opens the key 26 and closes the second key 27, which

gg connects the second light source 4 to power supply 1. Similarly, the third 8 and fourth 9 light sources are connected through the corresponding keys 28 and 29

3 one

switch 2. Next, the cycle repeats.

The first pulse from the device 25, arriving at the shift register 35, closes the first key 31 of the switch 19, which connects the first storage device 20 to the output of the dividing device 18. Subsequent pulses through the keys 32 - 34 respectively connect the storage devices 21-23, after which the cycle repeats.

The actual measurements are carried out as follows.

The light source 3 emits light of wavelength 1. One part of the radiation of source 3 passes through the cuvette 6 with the sample and passes through the light guide 14 to the second photodetector 17, the other part of the radiation reflected from the translucent plate 5 passes through the light guide 12 of the collector 10 and hits the photoreceiver 16. The electrical signals from the photodetector are fed to the input of a dividing device 18, at the output of which a signal Uj is formed.

The value of U from the output 18 of the second switch 19 is directed to the first storage device 20. Thereafter, the synchronizing device 25 connects to the power supply unit 1 a radiation source 8, which also emits light of a wavelength L ,. At the output of the device 18, a signal Uj is generated, which is stored by the second memory device 21. Similarly, sources 4 and 9 of light that emit light with a wavelength are included. The received signals Uj and U are stored on storage devices 22 and 23.

At the command of the synchronizing device 25, the values O 1,)) and C- are entered into the measuring device 24, where the operation

Y C Y: -Y-, and Uj r, (

where K is a constant coefficient

proportionality; g is the sample transmittance.

Thus, in the measuring device 24, a signal is formed that is equal to the ratio of the sample transmittance at two wavelengths

five

2

Yu

is

20 25

30 OR 40

45

0

five

534

In the invention, the measurement result does not depend on the current-values of photodetector conversion factors, which ensures that the error is preserved during the measurement time.

When measuring the concentration of absorbing substances, divider 18 is implemented in the form of a subtractive amplifier with logarithm at the input. In this case, the measurement result is

In Ig g, () - Ig) .С (} - С, (Л,),

where C is the concentration measured

substances.

Thus, the measurement is carried out by the differential method.

spectroscopy. I

The invention, in comparison with the known device, allows reducing the number of adjustments and extending the time interval between successive calibrations by half, which reduces the consumption of reagents and simplifies the operation of the analyzer.

Claims (1)

Invention Formula A photometric analyzer containing a pulsed power supply unit is connected through the first switch to the first and second light sources, whose optical axes are perpendicular, a translucent plate located at the intersection point of the optical axes at an angle of 45 to them, and the light sources have different working wavelengths and optical connected to the first photodetector and through the sample cuvette to the second photodetector; the outputs of the photodetectors are connected to a dividing device, which through the second switch to the first and second The output devices are connected to two inputs of the measuring device, as well as a synchronization device connected to the switching power supply unit, the first and second switches and the measuring device, characterized in that, in order to improve the measurement accuracy, it additionally contains the third and fourth light sources, the second translucent plate, the first and 513 the second dvuhsvetsvodnye collectors of light, the third and fourth storage devices, the third and fourth light sources are identical to the first and second sources, respectively, and their optical axes are perpendicular, the second translucent ilastine is installed at the intersection point of the optical axes of the third and fourth sources light at an angle of 45 to them, the first collector is installed in front of the first photodetector, and its light guides behind the first and second translucent plates along the radiation path on the second and fourth optical axes light sources, the second collector is installed in front of the second photodetector, and its light guides behind the cuvette with the sample during the radiation on the optical axis of the first light source and. downstream of the second translucent plate on the optical axis of the third light source. 53 ° the third and fourth memory devices are connected to two additional inputs of the measuring device, and the first and second switches are made in the form of four controllable keys and a four-channel shift register, the outputs of which are connected to the corresponding control inputs of the keys, the inputs of the shift registers of the switches are connected to the output the synchronization device, the inputs of the keys of the first switch are connected to the output of the pulse power supply unit, the inputs of the keys of the second switch - to the output of the splitter device -keeping, vEHOdy first switch keys are connected with respectively a first, second, third and fourth light sources and the outputs of the second switch keys are connected to inputs of the corresponding memory devices. VNIIPI Order 3822/36 Circulation 776 Subscription Arv-polygr. pr-tie, Uzhgorod, st. Project, 4