SU896525A1

SU896525A1 - Radiometric flaw detector

Info

Publication number: SU896525A1
Application number: SU802957857A
Authority: SU
Inventors: Феликс Михайлович Завьялкин; Юрий Олегович Поляков
Priority date: 1980-07-18
Filing date: 1980-07-18
Publication date: 1982-01-07

Description

(54) РАДИОМЕТРИЧЕСКИЙ ДЕФЕКТОСКОП(54) RADIOMETRIC DEFECTIVE

II

Изобретение относитс к технике неразрушающего контрол изделий, узлов и сварных соединений и может быть использовано в разных област х народного хоз йства дл неразрушающих испытаний радиационным методом.The invention relates to a technique for non-destructive testing of products, assemblies and welded joints, and can be used in different areas of national economy for non-destructive testing by a radiation method.

Известен радиометрический дефектоскоп с компенсацией изменений толщины объекта путем применени электромеханического преобразовател перемещени , подключенного к блоку сравнени 1.A radiometric flaw detector is known that compensates for changes in the thickness of an object by applying an electromechanical displacement transducer connected to the comparator unit 1.

Однако этот дефектоскоп имеет низкую достоверность обнаружени внутренних дефектов , так как в радиометрическом детекторе происходит усреднение потока регистрируемого излучени по площади окна коллиматора , а сигнал электромеханического преобразовател пропорционален максимальному значению толщины под базовой поверхностью измерительного наконечника.However, this flaw detector has a low accuracy of detecting internal defects, since the radiometric detector averages the flux of detected radiation over the area of the collimator window, and the signal of the electromechanical transducer is proportional to the maximum thickness below the base surface of the measuring tip.

Наиболее близким к предлагаемому по технической сущности вл етс радиометрический дефектоскоп, содержащий установленный в блоке радиационной защиты с коллимационным каналом детектор излучени , схему сравнени , индикатор, механизм перемещени объектов, блок измерени толщиныThe closest to the proposed technical entity is a radiometric flaw detector containing a radiation detector installed in a radiation protection unit with a collimation channel, a comparison circuit, an indicator, an object moving mechanism, a thickness measurement unit

контролируемого объекта, имеющий эжекторное сопло, индуктивный преобразователь давлени , камеру дл приема сжатого воздуха, причем детектор излучени через схему сравнени св зан с индикатором 2.the object to be monitored, having an ejector nozzle, an inductive pressure transducer, a chamber for receiving compressed air, the radiation detector being connected to the indicator 2 via a comparison circuit.

Недостатком известного устройства вл етс мала достоверность контрол вследствие вли ни флуктуации толщины контролируемого объекта. Это обусловлено тем, что преобразование толщины пневматическим преобразователем производитс с усреднением толщины по периметру измерительного A disadvantage of the known device is the low reliability of the control due to the influence of fluctuations in the thickness of the object being monitored. This is due to the fact that the thickness is converted by a pneumatic converter with the thickness averaged over the perimeter of the measuring

10 сечени сопла, в то врем как сигнал на выходе радиометрического детектора пропорционале : значению толщины, усредненному по площади измерительного сечени , равному полю зрени детектора.10 of the nozzle section, while the signal at the output of the radiometric detector was proportional to: the thickness value averaged over the measuring section area equal to the field of view of the detector.

Целью изобретени вл етс увеличение The aim of the invention is to increase

15 достоверности контрол за счет снижени вли ни флуктуации толщины объекта.15 control reliability by reducing the effect of fluctuations in the thickness of the object.

Claims

This goal is achieved by the fact that a radiometric flaw detector containing a radiation detector installed in a radiation protection unit with a collimation channel, a comparison circuit, an indicator, an object moving mechanism, a thickness measurement unit of the object being monitored and having an ejector one. a nozzle, an inductive pressure transducer, a chamber for receiving compressed air, the radiation detector being connected to an indicator through a comparison circuit and equipped with a means for converting a signal proportional to the average thickness of the object around the perimeter of the chamber for receiving compressed air connected to the pressure transmitter and to the comparison circuit, into a signal proportional to the average value of the object thickness over the area of the window of the collimation channel. The specified signal conversion means is designed as additional nozzles installed along the forward ejection nozzle, an inductive pressure transducer and a chamber for receiving compressed air, an integrator, a delay unit and a reading circuit, one input of which through a delay unit is connected to an additional inductive converter, and the second connected to an inductive transducer of the thickness measuring unit, the output of the subtraction circuit through the integrator is connected to the comparison circuit, with the additional nozzle It is located from the nozzle of the thickness measurement unit at a distance excluding their aerodynamic interaction, and the sum of the cross-sectional areas of both chambers for receiving compressed air is equal to the area around the collimation channel, and their shape absorbs the shape of the window of the collimation tube. its structural scheme. The radiometric flaw detector contains a radiation detector 2 connected to the comparison circuit 1 and a thickness measuring unit for the object being monitored, having an ejector nozzle 3 with a chamber 4 for receiving compressed air and an inductive pressure transducer 5, indicator 6. The flaw detector also contains serially connected reading circuit 7, integrator 8, an additional ejector nozzle 9 with a chamber 10 for receiving compressed air and an inductive pressure transducer 11. One input of the subtraction circuit is connected to an inductive transducer yes laziness thickness measuring unit, the other input through the delay line 12 is connected to a pressure transducer, and additional nozzle is arranged in front of the main nozzle. The drawing also shows the controlled article 13 and the radiation source 14. The device operates as follows. An article 13 with local heterogeneity located on the surface, for example, a hemispherical sink, is illuminated by a radiation source 14 and scanned by a detector

2. When the shell moves under the end of the nozzle of an additional chamber, a change in air pressure occurs, which is recorded by an inductive pressure transducer 11. This change is proportional to the increase in surface area formed by the end of the chamber and the surface of the product. Upon further scanning, the shell enters the field as seen by the radiation detector. The flux of detected radiation increases. This increase is proportional to the change in the thickness of the controlled product, averaged over the area of the collimator window. Along with the time, the main nozzle with the inductive transducer, similarly to the additional nozzle, records the movement of the same shell under the nozzle end. Then, the signal from the converter is fed to the input of the subtraction circuit 7, to another input of which a signal is fed from the additional converter delayed by delay line 12 for a time equal to the ratio of the distance between the inner faces of the nozzle to the scanning speed. The delayed signal from the pressure transducer of the additional and main nozzles is fed to different inputs of the subtraction circuit, and from the output the difference signal is fed to the integrator, the output of which is connected to the comparison unit. As a result, the signal of pressure transducers proportional to the average values along the contours of the measuring sections of the chambers for receiving compressed air are converted into a signal proportional to the average thickness of the product over the total area of the measuring sections equal to the surface of the visible radiation detector. Thus, at the output of the integrator, the signal has a functional transformation of changes in the thickness of products identical to that of the detector. Since both signals at the output of the comparison unit have the same shape, they cancel each other out and thickness fluctuations do not affect the effectiveness of the control. And internal disruption of density will be detected only by a radiation detector and therefore reliably detected. The use of the proposed device allows one to increase the reliability of the control by 1.5–3 times, depending on the frequency characteristics of signals formed by surface irregularities and internal defects. For example, empirically, when controlling molded products made from melted models with a braking layer, reliability increased by 2 times. Claims I. Radiometric flaw detector containing installed in a radiation protection unit with a collimation channel