SU1278683A2 - Photoelectric method for measuring dimensions and concentration of suspended particles - Google Patents

Abstract

The invention relates to instrumentation technology and can be used to monitor environmental pollution for measuring the size and concentration of suspended particles. The purpose of the invention is the measurement accuracy. The device contains a light source 1, a baffle 2 with a control unit 3, a focusing lens 4, an absorber 5, a receiving lens 6, a diaphragm of the field of view 7, a photodetector 8. The device also contains a threshold element 9, an analog switch 14, a processing unit with an amplitude analyzer J5, one-shot 16. Increased accuracy is achieved by adding an additional one-shot 17, three elements AND 10, 12, 19, two inverters 11, 18 and (L element OR 13.1 Il.

Description

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00 to 1 The invention relates to the control of the NS-measuring technique and can be used in meteorology, biology, chemical technology, control of pollution O1: the surface of the medium for measuring the size and concentration of suspended particles. The purpose of the invention is to improve the accuracy of measurements. The drawing shows a diagram of the device. The device contains a light source - laser 1. A deflector 2 with a block is installed on the path of the light beam, a focusing lens 4 and an absorber 5. A device for forming a particle flow (not shown) ensures the movement of particles with a non-KOTopoii speed V through the focal area1, shutdown 4 in directional, 11gr.g1.nd.icular plane of the drawing, Irismtta system: consists of object 6, a diaphragm of 7th zero. of length and a photodetector 8. To exit photoreceiver 8 connected threshold element 9 g First log The common element AND 10 is connected by one input through the threshold element 9 to the output of the photodetector 8. The first inverter I1 is connected to the output of the element I.K) with its output, and the output to one of the inputs of the second element I12, Logical e.pement. the input is connected to the output of the element I 12, and the output to.: - - to the control; it is analog input. about KJ.no4a 14. The signal input of this is connected to the output of the photodetector 8, and the output of the key - to the unit processing with an amplitude analyzer 15, the output of control unit 3 is connected in parallel to one of the inputs of the second one 16 pulse (pulse length. 1 pulse. The pulses are equal to the duration of the scattered light pulses) to the single vibrator 17 (specifying the beginning and end of the recording time, the duration of the pulses is equal to the recording time), the output of the single vibrator 16 is connected to the second input element And 10, the output of one. vibrato. 17 is hampered in parallel to the second input of the second element And 12 and to the input of the second inverter 18, the output of the last, and klgoche.n parallel to one short circuit Exo.qoH of the third element And 19 and to; vtsro .- .. at the entrance of the one-shot. 16, the second input of the element And 19 is connected 3 to the output of the element And 10, and the output - to the second input of the element OR 1,3, The device works as follows. The light beam from source 1 is focused by a lens 4 B on the flow of particles under study and scan this beam in the drawing drawing using deflector 2 with frequency f and amplitude AJ, the frequency f is chosen based on the condition where V is the speed of movement of particles, / A is the size of focal in terms of the level, by depleting the thrusts, the predetermined degree of uniformity of illumination of the countable volume (if, for example, the degree of uniformity is 90%, then l is determined by the level of 0.9 of the maximum light value of 1 point). The light beam is scanned at a constant speed (similar to scanning in oscilloscopes), the non-propagating light is extinguished by the trap 5, a. the light scattered by the particles under study is assembled by the lens 6 onto the photodrunker 8. Aperture 7 limits the size of the counting volume along the optical axis of the lens 4. When particles pass through the counting volume from each of them, a packet of scattered light pulses (converted by the photoreceiver 8 into the corresponding electrical .1-. Pulses). And the temporal position of each pulse in the stack relative to the beginning of the corresponding forward scan stroke is uniquely determined by the coordinate of the particle in the scanning direction. The control unit 3 generates pulses delayed with respect to each of the forward crawl steps of a scan, by a specified amount. These pulses trigger the one-shot 7, which forms a pulse with a duration equal to the nominal time of registration-1 and longer than twice the duration of the scattered light pulses (as the duration of this duration changes, the value of the counting volume changes). Simultaneously with the one-shot 7, the one-shot 16 is also started with a pulse duration equal to the duration of the output pulses of the photodetector 8 (i.e., the duration of the scattered light pulses). The second time (in one scan cycle) the odometer: the driver 16 is triggered by the rear 31 front of the pulse from the one-shot 17, i.e. at the end of the nominal measurement time. When the pulses from the photodetector do not coincide in time with either the beginning or the end of the nominal registration time (ie, with the front and rear edges of the pulse from the one-shot 17), if there is a logical potential at the output of the one-shot 16 and respectively at one of the inputs of the element And 10 the potential at the output of element 9 and respectively at the second input of the element And 10 is logical O, respectively, at the output of the element And 10 the potential is O, and at the output of the inverter 11 (and at the output of the element 12) the potential is 1, and the potential is output element Ta and 12, the output of OR gate 13 is equal to 1 during the pulse width monostable 17 is connected to the second input of AND gate 12 (at this time, the potential at the second input member 12 is equal to 1). Thus, the analog switch 14 is opened for the duration of the pulse from the one-shot 17 defining the nominal recording time. At this time, the pulses from the photodetector 8 arrive at the processing unit with an amplitude analyzer 15 measuring the amplitudes of the impulse packs. In this case, the potentials at the outputs of the inverter 18 and the element And 19 are unimportant. 35

When the pulse from the photodetector 8 coincides in time with the specified start of the registration time, if there is potential 1, the output of the one-shot 16 will also have potential 1 at the output of the threshold element 9. the output element And 12 potential is also equal to O. At this time, the potential at the output of the one-shot 17 is equal to 1, at the output of the inverter 18 O, respectively, at the output of the element And 19 the potential is zero.

Thus, since the potential at both inputs of the OR 13 element is zero, it is also equal to zero at the output, and the key 14 is closed.

At the end of the pulse from the photodetector 8 (this pulse ends no later than the pulse from the one-shot 16, and potential 1 is established at the corresponding input of the element 10 (from the moment of the end of the registration time to the end of

impulse from element 9). After the end of the pulse from the one-shot 17 at the output of the element And 12, the potential is equal to O regardless of the potential of the output of the inverter 11. However

the potential at the output of the inverter 18 is also equal to 1 (since the pulse from the one-shot 17 is already completed) And the potential at the output of the element And 19 is also equal to 1 (since

its input potential is 1). As a result, the key 14 will not be closed at the moment of the end of the pulse from the one-shot 17, but at the moment of the end of the corresponding pulse from the photo-receiver 8, and this pulse from the photo-receiver passes without distortion through the key 14. At each subsequent scanning cycle, the work is repeated. 3 ratora 16, since it starts earlier, and the duration of these pulses are equal) at the output of the element And 10 the potential O is established, at the output of the inverter 11 - potential 1, as a result, the key 14 opens before the end of the impulse receipt from the one-oscillator 17. Thus, if a scattered light pulse with a given start of recording time; this start is delayed until the end of said pulse. When the pulse from the photodetector 8 coincides in time with a given end of the registration time, i.e. with the back of the pulse from the one-shot 17 (before the start of the specified pulse from the 8V photodetector but after the end of the pulse from the one-shot 16), the potential at the output of the element And 10 is 0, the potential at the output of the inverter 11 is 1, the potential at the output of the one-vibration 17 is 1 (nominal registration time has not yet ended), the potential at the output of the element And 12 is 1, and the key 14 is open. At the moment of arrival of the pulse from the photodetector 8 at the input of the element And 10 connected to the inverter, potential 1 is established. At the time of termination of the nominal recording time, the back edge of the pulse from the single vibrator 17 through the inverter 18 starts the single vibrator

Claims (1)

Invention Formula A device for measuring the size and concentration of suspended particles, including a light source along which radiation a deflector with a control unit, a focusing lens, an absorber, a receiving lens and a photodetector, to which the threshold element and the analog key are connected, a processing unit with an amplitude analyzer are installed. five 0 five connected to the output of the analog key, and the first one-shot, connected by its input to the output of the deflector control unit, is about: In order to improve the measurement accuracy, a second one-shot, three I elements, two inverters and the OR element, the first input of the second mono-vibrator is connected to the output of the control unit, and the output is connected to the input of the first element AND, the second input of which is connected to the output of the threshold element, and the output to the input of the first inverter whose output is connected to the first input of the second element nA And, the output of which is connected to the first input of the RSHI element, the output of which is connected to the control input of the analog switch, the output of the first one-vibrator is connected in parallel to the second input of the second element And and to the input of the second inverter whose output is connected to the first input of the third element Both to the second input of the second one-shot, the second input of the third element AND is connected to the output of the first element AND, and the output to the second input of the element OR. Compiled by A. Churbakov Editor N. Margolin Tehred A. Kravchuk Proofreader S. Cherni Order 6825/39. Circulation 778 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4