SU896563A1 - Ultrasonic finder - Google Patents

Description

I

The invention relates to non-destructive agents and methods of control and can be used for ultrasonic testing of welded joints.

An ultrasonic finder is known that contains individual rectangular piezoelectric elements located on a rigid spherical surface of the MS.

 The disadvantage of this finder is the impossibility of smoothly changing the focal distance of the finder due to the rigid attachment of the elements to the spherical surface.

The closest in technical essence to the invention is an ultrasound finder containing a holder and a mosaic of piezoelements 2 fixed on it.

A significant drawback of the known searcher is the inability to change the focal length of the tester, i.e. reliability of detection of defects.

The purpose of the invention is to increase the reliability of control by changing the focal length of the mosaic.

This goal is achieved by the fact that the searcher is equipped with a hollow rod with a mechanism for its movement, a bellows and an elastic sheath encompassing a mosaic of piezoelectric elements fixed along the perimeter in the holding body and through the middle with a hollow rod connected to the bellows, and piezoelements are installed with a gap relative to each other.

Piezo elements are made in the form

IS ring sectors.

The inner side surface of the holder is a truncated cone.

20

Claims (2)

The movement mechanism is made in the form of a nut mounted in the housing with the possibility of rotation relative to the stem. The transfer mechanism is made in the form of a solenoid interacting with a hollow rod. Fig. 1 shows schematically the design of the ultrasound finder; in fig. 2 - a finder in which the movement mechanism is designed as a nut; in fig. 3 elastic shell with a mosaic of piezoelectric elements. The ultrasound control finder contains an acoustic prism 1, a mosaic 2 of piezoelectric elements and a current supply 3 mounted on a holder 4, the mosaic 2 being placed in an elastic sheath 5; Hollow stem 6 connects the elastic sheath 5 with the bellows 7. The periphery of the elastic sheath 5 is fixed to the holder k, and the middle of the hollow rod 6 is connected to the bellows 7. The mechanism for moving the hollow rod 6 is made in the form of a solenoid 8 with soft iron plates 9 and a spring 10. The cavity is closed, formed by the prism 1., the elastic shell 5, the hollow rod 6 and sil oxazolidinone 7 filled with contact fluid 11. Forces pattern 7 is fixed to the bracket 12 taken from interaction with the union nut 13Tokopodvod connector 3 terminates. Mosaic 2 of piezoelectric elements consists of annular sectors 15- The inner side facing to mosaic 2 of piezoelements, the surface of the holder k has the shape of a truncated cone. The searcher works as follows. Electrical high-frequency pulses through the connector 1 and the current lead 3 serves on the mosaic 2 of the piezoelectric elements. Acoustic contact of mosaic 2 with prism 1 of the searcher is made using contact liquid 11, for example glycerol, which is filled with C-ilfon 7. Mosaic 2 from the piezoelectric elements sends ultrasound pulses to the controlled item (see not shown) through prism 1. The ultrasonic vibrations are focused by changing the curvature of the mosaic 2 from piezoelectric elements encased in an elastic (e.g. rubber) casing 5 for which, using a displacement mechanism made in the form of a hollow rod 6 and a nut 13, kinematically connected with the thread of the hollow rod 6 , move the central part of the mosaic 2 in the axial direction. In this case, the peripheral part 4 of the elastic shell 5 slides along the conical surface of the holder k, the hollow rod 6 compresses the bellows 7, the contact liquid 11 through the opening in the FLOOR rod b enters the cavity between the searcher's prism 1 and the mosaic 2. The greater the amount of movement of the central part of the mosaic, the greater its curvature and the smaller the focal length. The spring 10 constantly tightens the nut 13 to the holder C, the limits of the change in focal length are determined by the size of the elements, the distance between them and the elastic properties of the shell 5. The hollow stem 6 is moved by means of a solenoid 8 mounted on the holder 4 coaxially with the hollow stem 6, by changing the polarity of the supply voltage of the windings of the solenoid 8, while the soft iron plates 9 are alternately attracted or repelled. The contact fluid 11 is similar, as in the nep-i BOM case, when the hollow rod 6 moves upwards it enters the cavity between mosaic 2 and prism 1 of the searcher. When the hollow rod 6 moves downward, the contact fluid 11 enters the SNOBE into the bellows 7. The focal length in this case continuously changes from infinity to the value determined by the curvature of the mosaic of elements. When the central part of the mosaic 2 is moved in the axial direction, the individual piezo elements of the mosaic rotate relative to each other at a certain angle, forming a quasispherical surface. To improve the geometry of the quasi-spherical surface, the mosaic piezoelectric elements are made in the form of annular sectors. 15This finder allows changing the focal distance within wide limits, which increases the reliability of the detection of defects, especially in coarse-crystalline structures. Claim 1. Ultrasound finder containing a holder and a mosaic of piezoelements fixed thereon, characterized in that, in order to increase the reliability of control by changing the focal length