Polyethylene pipeline weld joint ultrasonic detection dedicated transducer

Abstract

The invention provides a transducer specialized for polyethylene pipeline weld ultrasonic wave detection, which has a simple detection method, high sensitivity and reliable detecting result. The transducer comprises a metal housing, a wiring pole, sound absorption materials, a piezoelectric wafer and a delaying lump, wherein, the delaying lump comprises a left delaying lump and a right delaying lump, the left delaying lump is connected with the right delaying lump by a connecting rib, the piezoelectric wafer is respectively arranged on the tops of the left and the right delaying lumps, the wiring pole comprises a signal-emitting wiring pole and a signal-receiving wiring pole, wherein, the signal-emitting wiring pole and the signal-receiving wiring pole are respectively connected with the piezoelectric wafer at the two sides. The transducer is characterized in that a magnetic block is arranged in the neutral position between the left and the right delaying lumps below the connecting rib.

Description

(1) Technical field [0001] The invention relates to the field of ultrasonic detection, in particular to a special transducer for ultrasonic detection of welded seams of polyethylene pipes. (2) Background technology [0002] Polyethylene pipes replace steel pipes because of their corrosion resistance, easy forming, and low price, and are widely used in urban underground gas pipelines. The welding method of polyethylene pipes is the heat fusion method. Two straight-through polyethylene pipes are butt-jointed, and the joints of the two polyethylene pipes are partially melted and welded by electric heating to form a butt weld. The prefabricated polyethylene pipe bent at a certain angle such as 90° is put on the turning part of the two straight pipe joints, and then heated by electricity to melt and weld the inner wall of the jacket pipe and the outer wall of the jacket pipe together to form a socket joint at the pipe bend welds. Since polyethylene pipes are welded in trenches ...

AI Technical Summary

Problems solved by technology

Since polyethylene pipes are welded in trenches dug on the open-air construction site, soil, sewage and other dirt on the surface of the pipes are likely to stick to the pipe joints and be brought into the welds, causing the welded pipes to leak. The specific gravity is higher than that of air, and the gas leaked from the weld of the polyethylene pipe is not easy to float away with the wind, but will slowly enter the user from the pipe entrance along the pipe, causing personnel poisoning

At present, metal pipe or forging detectors are usually used for ultrasonic testing of polyethylene pipe welds, but the sound velocity of ultrasonic longitudinal waves of polyethylene pipes varies in the range of 2000m / s to 2200m / s, and the ultrasonic attenuation coefficient of polyethylene materials μ = 490dB / m to 510dB / m (that is, 0.49dB / mm~0.51dB / mm), the ultrasonic attenuation of the material is large, which limits the propagation distance of the ultrasonic wave. The acoustic characteristics of the above two polyethylene materials lead to unsatisfactory detection results.

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