GB2190493A

GB2190493A - Ultrasonic wheel probe with means for supplying coupling fluid to a workpiece

Info

Publication number: GB2190493A
Application number: GB08611861A
Authority: GB
Inventors: Viktor Alexandrovich Bobrov; Vyacheslav Dmitrievich Mischuk
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-05-15
Filing date: 1986-05-15
Publication date: 1987-11-18
Anticipated expiration: 2006-05-15
Also published as: DE3615392A1; GB8611861D0; FR2599509A1; GB2190493B; FR2599509B1

Abstract

A device for ultrasonic inspection of workpieces comprises a chamber 1, containing an acoustically transmissive medium 2, made up of two disks 3,4 and an annular rim 7 which is acoustically and hydraulically transmissive and is hermetically secured to the disks 3,4. A shaft 12 extends through the disks 3,4 and axial passages 16,17 are provided in the ends of the shaft 12. One passage 16 has an outlet to the lateral surface of the shaft 12, and contains an RF cable 42 while the other passage 17 has an outlet to a recess 18 made in the body of the shaft 12 between the passages 16,17. An attachment assembly 21 is fitted into the recess 18 and provided with a holder 28 to which an ultrasonic transducer 40 is mechanically connected. The rim 7 is a laminate of a draining layer eg a metallic screen, a reverse osmosis membrane 10 eg cellulose and a substrate 11 eg a nylon screen. <IMAGE>

Description

SPECIFICATION Device for ultrasonic inspection of workpieces This invention relates to non-destructive testing of materials and, more particularly, to ultrasonic inspection devices. Such devices can be used for ultrasonic product quality control, e.g. of welded joints and rolled sheets.

Known in the art is a device for ultrasonic inspection comprising a chamber with an acousticallytransmissive medium, which is made up oftwo disks and an annular rim which is made acousticallytransmissive and hermetically sealed when secured to the disks, the chamber being provided with a device for input ofthe acoustically transmissive medium, an axle arranged inside the chamber, one end of the axle being furnished with a duct along the geometrical axis thereof, which has an outletto the lateral surface of the axle which extends through the disks, a mounting attachment with a holder, which is fitted into the duct in the body of the axle, and an ultrasonictransducer mechanically secured to the holder.

In this device for ultrasonic inspection the acousticallytransmissive medium input element is an opening in one of the disks. The device also comprises a means for supplying the acoustically transmissive medium to the point where the external surface of the rim is in contact with the inspected workpiece.

Butthis device is deficient in that the opening is provided in one disk,sincethe acoustically transmissive medium is let in and out of the chamber only once. Uninterrupted supply of the acoustically transmissive medium to the area between the annular rim and the inspected workpiece carried on in orderto provide a permanent contact therebetweenisdonefrom outside. Anyinterruption in the supply of the medium can result in gaps, formation of bubbles and, consequently, poor quality of control.

What is desired is a device for ultrasonic inspection which can ensure better quality of inspection.

The present invention provides a device for ultrasonic inspection, comprising a chamberwith an acoustically transmissive medium, which is made up oftwo disks and annular rim which is made acoustically transmissive and hermetically secured to said disks, and provided with an element for letting in the acousticallytransmissive medium and an axle arranged inside said chamber and having at one end thereof and along the geometrical axis thereof a duct emerging to the lateral surface of the axlewhich extendsthrough both disks, an attachment assembly featu ring a holder, which is fit into a recess made in the body of the axle so that it communicates with the duct, and an ultrasonic transducer mechanically secured to the holder of the attachment assembly, in which the element for letting the acoustically transmissive medium into the chamber is a passage for letting the acoustically transmissive medium into the chamber, provided at the other end of the axle along the geometrical axis thereof and communicating with the recess, while the annular rim is additionally made hydraulically transmissive so that the acoustically transmissive medium can be let out of the chamber.

It is advisable that in a device for ultrasonic inspection the annular rim should be made hydraulicallytransmissive for letting the acoustically transmissive medium out of the chamber by combining a draining layer, a reverse osmosis membrane, and a substrate arranged in this sequence in relation to one another and to the workpiece.

The holder of the attachment assembly preferably comprises a carriage provided with wheels touching the substrate.

The device according to the invention can provide uninterrupted supply of the acoustically transmissive medium during inspection and thus improves the quality of inspection.

The invention will now be described in more detail, by way of example, with reference to the accompanying drawings, in which: Figure lisa longitudinal sectional view of a device for ultrasonic inspection; and Figure2 shows an enlarged view of detail A of Figure 1.

The illustrated device for ultrasonic inspection comprises a chamber 1 (Figure 1) containing an acousticallytransmissive medium 2. The chamber 1 is made up oftwo disks 3 and 4, with annularseals5 and 6, and an annular rim 7 which is made acoustically and hydraulicallytransmissive for letting the acousticallytransmissive medium 2 out of the chamber 1. The rim 7 comprises (Figure 2) a draining layer9 (for example, a metallic screen), a reverse osmosis membrane 10 (for example, cellulose), and a substrate 11 (for example, a nylon screen).

A shaft 12 is arranged inside the chamber 1 so that it extends through the disks 3 and 4. Passages 16 and 17 are provided in ends 13and 1 4 of the shaft 1 2 along its geometrical axis 15.

The passage 16 has an outletto the lateral surface of the shaft 12, while the passage 17 has an outlettoa recess 18 provided in the body of the shaft 12, in the central portion thereof between the passages 16 and 17. The recess 18 has openings 19 and 20. An attachment assembly 21 is arranged in the recess 18.

The assembly 21 comprises a rod 22 extending through the openings 19 and 20 of the recess 18, and a spring 23 fitted on the rod 22. A screw 24 is screwed into the opening 20 of the recess 18 coaxially with the rod 22. A slot 25 is provided in the rod 22 to accommodate a fixing arm 26. A carriage 27 of a holder 28 is secured to the rod 22. The carriage 27 is provided with wheels 29 resting on the substrate 11 ofthe rim 7. Inputs ofthe passages 16 and 17 are provided with, respectively, an RF connector 30 and a nipple31. Casings32 and 33 aresymmetrically arranged on the shaft 12, on both sides of the recess 18 so that they are rigidly secured, respectively, with the disks 3 and 4 by bolted connections 34.Seals 35 and 36 and bearings 37 and 38 are respectively installed inside the casings 32 and 33 on the shaft 12, on both sides on the assembly 21. A prism 39 of an ultrasonictransducer40with a piezoelectric plate 41 isfitted into the carriage 27 of the holder 28. The piezoelectric plate 41 is electrically coupled with the connector 30 by means of a cable 42 passed through the passage 16.

The above-described device for ultrasonic inspection operates as follows.

The device is placed on a scanning mount (not shown) and the assembly is placed on a workpiece 8 (Figure 1) to be inspected. Afterthat, the acoustically transmissive medium 2 is supplied, via the nipple 31, to the chamber 1 and expels the air in the chamber 1 through the acoustically and hydraulically transmissive rim 7. The seals 35 and 36 preventthe acousticallytransmissive medium 2from penetrating to the bearings 37 and 38. When a specific pressure of the medium 2 is obtained, it starts seeping through the rim 7 and produces a permanently moist layer on the external surface of the rim 7, particularly on the draining layer 9. The annular seals 5 and 6 reliably keep the rim 7 from being dislocated by the pressure ofthe medium 2 in the chamber 1.

The device is then transported along the workpiece 8. During the movement the rim 7 rolls on the workpiece 8 and wets the surface of the workpiece 8 owing to the permanently moist draining layer 9. In this manner reliable acoustical contact of the workpiece with the ultrasonic transducer40 is maintained, and ultrasonic vibrations are introduced into the workpiece 8. The workpiece 8 is being inspected by the transducer 40.

The reverse osmosis membrane 10 is only permeable in one direction, that istowards the workpiece 8.

As the device is transported overthe workpiece 8, the wheels 29 roll on the internal surface ofthe substrate 11 ofthe annular rim 7, but the substrate 11 is at no time in contact with the ultrasonictransducer 40. Wear of the substrate 11 and the transducer 40 is therefore minimal.

When irregularities, such as scale, dents, or bulges, occur on the surface ofthe workpiece 8, the rod 22 allows the holder 28 to rise before the obstacle and lowers it afterthe obstacle has been negotiated, the gap between the substrate 11 and the transducer 40 being maintained constant. The holder 28 cannot rotate about its axis, because of the fixing arm 26.

The acousticallytransmissive medium 2 is supplied to the recess 18 via the passage 17.

Echo signals ofthe defects are supplied via the piezoelectric plate 41,the high-frequency cable 42, and the connector 30 to an inspection unit (not shown).

This device permits ultrasonic inspection in vacuum, which is an important addition to the application field of such devices.

The device can be also used for ultrasonic inspection of overhead welds, which is another addition to the field of application of such devices.

Claims

1. A device for ultrasonic inspection of workpieces, comprising a chamberfor containing an acoustically transmissive medium, the chamber comprising two disks and an annular rim which is acoustically and hydrau lical Iy transmissive in order to let the acoustically transmissive medium out of the chamber and is hermetically secured to the disks; a shaft extending through the disks and having axial passages in its respective ends, one passage having an outlet to the lateral surface ofthe shaft inside the chamber, and the other passage having an outlet to a recess in the body of the shaft between the passages; an attachment assembly fitted into the recess and having a holder; and an ultrasonic transducer mechanically connected to the holder.

2. A device as claimed in claim 1, in which the annular rim comprises, in sequence, a draining layer, a reverse osmosis membrane, and a substrate.

3. A device as claimed in claim 2, in which the holder comprises a carriage having wheels which are in contact with the substrate.

4. Adeviceforultrasonic inspection of workpieces substantially as described above with reference to, and as shown in, the accompanying drawings.