SU1509779A1 - Device for detecting metal inclusions in flow of raw materials - Google Patents

Abstract

The invention relates to instrumentation technology and can be used in the detection of metallic objects and particles in a stream of raw materials that are non-conductive or weakly conductive material. The purpose of the invention is to increase the sensitivity and noise immunity of the device. For this purpose, the device uses a sensor with four sections spaced apart and oriented at different angles to the direction of movement of the raw material. The receiving coils of the sections to compensate for the primary field and the noise field are switched on in pairs and form two channels of signal processing. The use of a prohibition scheme and delay links allows for the spatial-temporal separation of signals, which makes it possible to eliminate false positives of the device while simultaneously acting on interference in both channels, in the event of interference in one of the channels. 4 il.

Description

The invention relates to instrumentation engineering, in particular, to devices for detecting metallic objects and particles in a stream of raw material that is a non-conductive or weakly conductive material.

The purpose of the invention is to increase the sensitivity and noise immunity of the device while reducing the size and weight of the sensor.

FIG. 1 shows a block diagram of a device for detecting metallic inclusions in a stream of raw materials; in fig. 2-4 are time diagrams for the operation of the device.

 A device for detecting metal particles contains induction, sensor 1, made of sections 2-5, generator 6, amplifiers-formers 7 and 8, standby multivibrators 9 and 10, first delay link 11, second delay link 12, OR element 13, circuit 14 ban, the element And 15, the waiting multivibrator 16, the majority scheme 2 of 3 17 and the indicator 18.

The device works as follows.

Useful signals arising in the chains of counter-switched receiver coils of sections 2, 5 and 3, 4 received

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They are input to the amplifiers 7 and 8, where they are amplified, detected, extracted and amplified by video pulses and the formation of logical signals of standard amplification. These signals then go directly to the inputs of the waiting multivibrators 9 and 10. Since sections 2 and 5 are spaced far enough apart, the pulses appearing in one channel (channel I) are noticeably shifted in time. This circumstance is used as a temporary indication of the separation of signals. Sections 3 and 4 are located close to each other, therefore the signal in their circuit (channel II) is obtained as one radio pulse

Let us assume that signals occur in sections 2 and 5 (first in section 2, then in section 5, figs, 2). This is possible when an elongated metal particle passes, I is oriented parallel to the turns of sections 3 and 4. This starts the waiting multivibrator 9 from the pulse induced by the metal particle in the measuring section 2, the potential from the output of the waiting multivibrator 9 enters to the input of the delay section 11 the delay time of which is chosen greater than the duration of the output pulse of the amplifier 7, Therefore, the resolving potential from the link 11 of the delay element 11 arrives later than the pulse from the amplifier — bodies 7, the element 15 does not give permission for the triggers of the waiting multivibrator 16. By the moment of arrival of the pulse caused by the same particle, but already from section 5, the output of the delay link 11 will be a high voltage level, which through the element OR 13 element 15 and the standby multivibrator 16 is launched. The prohibition scheme 14 serves to prohibit a signal from the waiting multi-vibrator 9 with a signal from the waiting multi-vibrator 10 and is designed so that it is triggered if the signal from the waiting multi-vibrator 10 comes first, and the second from the waiting multi-vibrator 9, otherwise the circuit .14 prohibition does not work, t, e, does not prohibit the passage of a signal from the waiting multivibrator 9. So

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as the waiting multivibrator 10 is turned off, the prohibition circuit 14 does not work, and the signals of the waiting multivibrators 9 and 16 affect the majority 2 of 3 17, which generates a signal at the output, and the indicator 18 goes off,

When signals appear sequentially, in sections 2 and 3 (FIG. 3), pending multivibrators 9 and 10 are triggered and act on the majority circuit 17, which generates a signal to trigger the indicator 18,

When a signal occurs in section 3, and then in section 5 (FIG. 4), the waiting multivibrator 10 is triggered first, the potential from the output of which is fed through delay link 12 to the OR 13 element and the prohibition circuit 14. When a pulse arrives on channel 1 from section 5, the waiting multivibrators 9 and 16 are simultaneously triggered, since the second input of the AND 15 element by this time already has a resolving potential coming from the OR 13 element, but since the waiting multivibrator 10 is triggered earlier than the waiting multivibrator 9, the prohibition scheme 14 does not pass the signal of the latter to the majority scheme 17; Thus, the majority scheme 17 is affected by the signal from the ARRAY of multivibrators 10 and 16, thereby aligning the temporal and spatial distribution position of signals and their sources (sensor sections),

The use of a prohibition scheme allows the device to be protected from the simultaneous action of impulse noise in both channels. When interference occurs in the sections (for example, in sections 2 and 3), the waiting multivibrators 9 and 10 are triggered at the same time. However, the prohibition circuit 14 does not pass the signal of the pending multivibrator 9 ipa to the majority circuit 17, and the time delay introduced by the link 12 prevents the trigger standby multivibrator 16 simultaneously with multivibrator 10,

The proposed device can significantly increase the noise immunity and sensitivity of the device in comparison with the known, reduce | dimensions and weight of the sensor with the same geometric dimensions of the receiving meshes.

51509779

Claims (1)

Invention Formula A device for detecting metallic inclusions in the flow of raw materials, containing an induction sensor, made of three separate sections, each containing a receiver coil and inductor, a generator, the output of which is connected to the reference inputs of two amplifiers of the formers, an indicator, a majority of , element IL1, element I, the first, second and third standby multivibrators, the generator output being connected to the input of the induction sensor 15, the outputs of which are connected to the inputs of driver amplifiers whose outputs are below They are connected to the inputs of the first and second multivibrators, respectively, and the output of the majoritarian scheme 2 of 3 is connected to the input of the indicator, characterized in that, in order to increase the sensitivity and interference tolerance, they are spaced apart and contain each inducing and receiving coils, combined in space, with the receiving coils of sections located symmetrically relative to the center of the sensor, included in pairs and counter and contain the first and second delay elements and the prohibition circuit, the input of the first waiting multivar The selector is connected to the first input of the I element, and the output is connected to the input of the first delay level and the input of the inhibit circuit, the output of the second standby multivibrator is connected to the second input of the inhibit circuit, to the first input of the majority scheme and through the second delay link to the first input of the majority scheme, the output of the first delay element - to the second input of the element .OR, whose output is connected to the second input of the element And, the output of the element And is connected to the input of the third waiting multivibrability, into the inductive sensor of the additional 25 dkgaochen introduced to secondary tively fourth section, rum entry majority circuit. the sections are spaced apart and contain each inducting and receiving coils combined in space, while the receiving coils of sections symmetrically relative to the center of the sensor are pairwise-opposite and contain the first and second delay elements and the inhibitor circuit, the input of the first waiting multivibrator is connected to the first input element is And, and the output is connected to the input of the first delay level and the input of the inhibit circuit, the output of the second multivibrator is connected to the second input of the inhibit circuit, to the first input the majority scheme and through the second delay link - to the primary input of the majority scheme, the output of the first delay element - to the second input of the element .OR, the output of which is connected to the second input of the element And, the output of the element And connected to the input of the third waiting multivibr FIG. one Fie.2 SES D Section 5 FIG. J Section J. Section 5 I n ъ. Take out I flwx.W 5WX / 5 I -R ;