SU523303A1 - Photometric device - Google Patents

Description

one

The invention relates to the field of photometry and can be used, for example, to determine the content of asbestos fiber in ore by its reflectivity.

A two-beam photometer is known, which contains a light source, a reference object, a photodetector that receives light signals transversely from the reference and controlled objects and a recording device. The sensitivity of such a device is relatively small.

It is also known a photometric device containing a light source, a reference object, a photoreceiver, receiving light signals reflected alternately from a reference and controlled objects n amplifier with an automatic gain control circuit, controlled by a signal from a reference object.

A disadvantage of the known instrument is that the signal processing circuit in it contains a switch of non-irradiated PMNCs from a reference image, controlled by a expansion device with additional sensors, which complicate the design and reduce its reliability. In addition, in this device, the signals from the reference sample enter the amount of non-radiation from the test surface, since the latter, after the amplifier, are totally integrated into the integrator. The total recording of signals from the surface under study, as well as from siTuioiniofi, leads to additional measurement and measurement accuracy.

The purpose of the invention is the construction of a measuring system; 1.

The goal is accessible by the fact that the mouth of S / V 5 o is equipped with a diode. Compensation wave 1) Tmetro :. and a separator of pulses of amplitude than, with the diode input of the: voltmeter connected to the input of the difference, the amplitude of the pulses in amplitude and the output of the amplifier with the automatic gain control circuit. output of the pulse separator according to al-, pl: 1t - ;, r plug through resistive 110-caldeasato;): 1y |. chain to the input of the silnet, npii4e: fl; lo; p1l1 object has a surface with

reflective ability. the reflection coefficient of the object to be loosed. The amplitude section of pulses is made in the form of two a 1 nlmt. 1 of the villages KTor ;; -; a power amplifier, with the inputs of the amnlltude selectors connected; ; between cociosi, g: output i of one of the ampltudo selectors plug

to the input of the IMNAL amplifier, output

pogo is connected to the input of the second amp. other selector.

Claims (2)

Fla. I shows lusmo / k; 1a cxoia (a photometric device; Fig. 2 shows a time diagram of pulses at the output of an amplifier with a variable transmission coefficient. The photometric device contains light sources 1, 2, photodetectors 3, 4, receiving the signal from the controlled 5 and reference 6 objects, a modulator, made in the form of a shutter 7 with a sector window 8, a measuring circuit with a bridge circuit 9, an amplifier 10 with an automatic gain control circuit, a diode compensation voltmeter 11, a resistor-capacitor circuit 12 and a pulse amplitude separator, made in the form of amplitude selectors 13, 14 and pulse amplifier 15. The shutter is driven by the electric motor 16. The reflectivity of the surface of the reference object exceeds the greatest reflectivity of the surface of the object to be monitored (asbestos ore sample) due to that it is made, for example, a mirror. The photometric device operates in the following manner. The obturator 7 (Fig. 1) rotates from the electric motor 16 and at some point in time through the sector window 8 transmits the light flux from the light source 1 to the monitored object 5. The luminous flux reflects from the monitored object 5 and enters the photodetector 3, which by means of a bridge 9 converts the light into a voltage pulse 17 (Fig. 2) amplified by the amplifier 10. Next, the voltage pulse 17 arrives at the diode compensation voltmeter I. When the shutter 7 is rotated through an angle of 180 ° through the sector window 8 from source 2, the reference light is illuminated The object is 6, and the object to be monitored 5 is blocked at this time and not illuminated. The luminous flux from the reference object 6 is reflected and converted by the photoreceiver 4 into a voltage pulse 18 (see Fig. 2). The voltage pulse 18 from the reference object 6, due to the high reflectivity of its surface, exceeds the amplitude of the pulse 17 from the object to be monitored 5 and is therefore allocated by the amplitude selector 14. In the ide of the pulse At / (see Fig. 2). Next, the pulse Afy is amplified by the pulse amplifier 15 and in positive polarity is applied to the input of the amplitude selector 13, the input of which also receives the same reference pulse as on the input of the amplitude selector 14. Thus, the voltage at the input of the amplitude selector 13 depends only on amplitude values of reference impulses. The reference pulses from the amplitude selector 13 are accumulated by the resistor-capacitor circuit 12, the voltage of which is controlled by the automatic gain control circuit. When operating in a dusty environment, the front surfaces of the photodetectors 3 and 4 are contaminated and their sensitivity decreases. This could lead to errors in the measurements, but when the sensitivity of the photodetector 4 decreases, the amplitude of the pulse 18 from the reference object decreases, which leads to a decrease in the magnitude of the negative voltage on the resistive-co-capacitor circuit 12. A decrease in the negative voltage on the input of the amplifier 10 leads to move the operating mode of the amplifier 10 in the area of hypersensitivity. Thus, a decrease in the sensitivity of the photodetectors is compensated for by an increase in the sensitivity of the amplifier 10, which reduces the measurement error in a dusty environment. Since the amplitude of the pulses 17 from the object being monitored (working pulses) is obviously less than the amplitude of pulses 18 from the reference object (reference pulses), the working pulses do not pass into the sensitivity adjustment circuit, cut off by the amplitude selector 13. The standard pulses 18 together with the working pulses 17 are fed to the input of a diode compensation voltmeter 11. A diode compensation voltmeter 11 has a reference voltage circuit to compensate for the voltage generated by the reference pulses 18. Therefore, the readings of the diode ompensatsionnogo voltmeter 11 are proportional only to the reflectivity of the controlled object 5, and it is judged on soderl: AANII, for example, free of asbestos fiber in the ore sample. The proposed device eliminates additional photodetectors, light sources, a switch for synchronous detection, which simplifies the design of the device.1 Claim 1. A photometric device containing a light source, a reference object photodetector receiving light signals reflected alternately from the reference and monitored objects, and An amplifier with an automatic gain control circuit controlled by a signal from a reference object, characterized in that, in order to simplify the design and improve measurement accuracy, it is equipped with a diode compensation voltmeter and pulse separator in amplitude, the input of the diode compensation voltmeter connected to the input of the pulse separator in amplitude and output of the amplifier with an automatic power control circuit, the output of the pulse separator in amplitude connected through a resistive-capacitor circuit input amplifier, and the talon object has a surface with a reflective ability that exceeds the greatest reflectivity of the target object. 2. The device according to claim 1, characterized in that the pulse separator in amplitude is made in the form of two amplitude selecto ditch and a pulse amplifier, iric / m inputs of amplitude selectors connect:; eksg megdu by itself, and the output of one of amplitude selectors is connected to the input of a pulse usigltel, is connected to the input; Yuogo 1ltl11g D110go selector. about W y / 7 L,