SU1093887A2 - Device for checking cylinder-shaped article diameter - Google Patents

Abstract

DEVICE FOR THE CONTROL OF THE DIAMETER OF CYLINDRICAL PRODUCTS on the author. St. № 1033855, different from the SU .... 1093887 A 3

Description

The invention relates to non-destructive testing of the diameter of cylindrical articles and can be used in the manufacture of pipes. A basic device for controlling the diameter of cylindrical products is known from the main author, No. 1033855, which contains a series-connected auto generator, a block of overhead eddy current transducers, an amplitude detector and an indicator connected between an amplitude detector and an indicator, a series-connected differentiating circuit, a threshold unit, a coincidence circuit pulse duration ts, connected between the amplitude detector and the second input of the coincidence circuit in series connected peak detection , A voltage divider and a comparator, a second input coupled to an output of the amplitude detector G1 3. However, the device is characterized nedos tatochnoy reliability control due to influence of change of the traveling speed izdeTsel invention - Dost zernosti increase control. The goal is achieved by having a device for controlling the diameter of cylindrical items containing a series-connected auto-oscillator, a block of overhead eddy current transducers, an amplitude detector and an indicator connected between an amplitude detector and an indicator connected in series to a differentiating circuit, a threshold unit, a coincidence circuit and a unit pulse duration measurements connected between the amplitude detector and the second input of the coincidence circuit are subsequently connected; The peak detector, voltage divider and comparator, the second input of which is connected to the output of the amplitude detector, are equipped with a second differential circuit, a trigger, and a second unit. measuring the pulse duration and the dividing unit, the input of the second differentiating circuit is connected to the output of the threshold unit, and the output is additionally connected to the reset input of the peak detector voltage, the second input of the dividing unit is connected to the output of the first measuring unit of the pulse duration and the output to the indicator. 10 87J FIG. 1 is a block diagram of the device proposed; in fig. 2 - voltage plots of individual units of the device. The device for monitoring the diameter of cylindrical products contains a series-connected auto-oscillator 1, a block 2 of eddy current transducers, an amplitude detector 3, a differentiating circuit 4, a threshold block 5, a matching circuit 6, a pulse duration measuring unit 7 connected between the amplitude detector 3 and a matching 6 pictodector 8 , voltage divider 9, comparator 10 connected between amplitude detector 3 and coincidence circuit 6, the output of threshold unit 5 is connected to series-connected second differential 11, the trigger 12, the second pulse width measurement unit 13, the dividing unit 14, to the input of which the pulse width measuring unit 7 and the indicator 15 are connected, the second output of the second differentiating circuit 11 connected to the second input of the pick detector 8. The device works as follows . The self-oscillator 1 feeds a sinusoidal current with a block 2 of eddy current transducers, which consists, for example, of two identical overhead transducers connected in a differential circuit and located along a fixed distance of the product (the cylindrical product must move in the transverse direction, for example, roll down an inclined plane ). As a result of the sequential movement of the product in the control zone of both transducers, a voltage appears at the output of unit 2, so that after it is rectified, two bell-shaped pulses appear at the output of the amplitude detector 3 (Fig. 2). These pulses act on a differentiating circuit 4, and two bipolar pulses appear at its output, the transition from one polarity to another occurs when the maximum output voltage module of the converter unit 2 reaches a maximum. Changing the polarity of the output voltage of the differentiating circuit 4 triggers the porous block 5 so that a high potential at its output remains until the voltage of the differentiating circuit 4 again drops to zero or changes to another polarity. At the output of the second differentiating circuit 11, in this case, short pulses of positive polarity appear, corresponding to the leading edges of the pulses of the threshold unit 5, and negative polarity, corresponding to the falling edges of the same pulses. In this case, the negative polarity pulses reset the voltage of the peak detector 8, and the positive polarity pulses the trigger 12 so that at its output a high potential is held for a period of time between the first and second triggering pulses, i.e. during the time the product travels the distance between the two measuring transducers of the tree 2. At a fixed distance, this time is inversely proportional to the speed of the product. The output voltage of the amplitude detector 3 is also fed to the input of the peak detector 8, the output voltage of which increases, reaches the maximum voltage of the amplitude detector 3, and then remains unchanged until the negative pulse of the differentiating circuit 11 arrives. This voltage is through a divider 9 voltages with a division factor of 1 / k (Fig. 2) affect 874 one of the inputs of the comparator 10, and another input of which receives voltage from the output of the amplitude detector 3, while it is greater than the voltage of the divider 9, to the output comparator 10 there is a high potential. The output voltages of the threshold unit 5 and the comparator 10 are fed to the inputs of circuit 6, so that two pulses are obtained at the output of the measurement period, the duration of which is directly proportional to the diameter of the product under test and inversely proportional to the speed of movement of the product. These pulses enter the pulse width measurement unit 7. A similar second unit 13 receives a pulse from the output of the trigger 12. The output voltages of the units 7 and 13 are fed to the inputs of the division unit 14, the signal from which goes to the indicator 15, scaled in units of the diameter of the products. Obviously, the output signal of dividing unit 14 does not depend on the speed of movement of the product. A device for controlling the diameter of cylindrical articles will allow measurements of the outer diameter independently of both the electromagnetic parameters of the material and the wall thickness of the pipe or the thickness of the coating, as well as changes in the speed of movement of the product. This will provide high accuracy to the accuracy of control of products from non-magnetic and ferromagnetic materials.

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Claims (1)

DEVICE FOR CONTROL OF DIAMETER OF CYLINDRICAL PRODUCTS by ed. St. No. 1033855, characterized in that, in order to increase the reliability of the control, it is equipped with a second differentiating circuit, a trigger, a second pulse duration measuring unit and a division unit connected in series, the input of the second differentiating circuit is connected to the output of the threshold unit, and the output is additionally connected to the input peak voltage detector, the second input of the division unit is connected to the output of the first unit for measuring the pulse duration, and the output to the indicator. FIG. 1