RU1795366C - Pickup for recording of signals of acoustic emission - Google Patents

Abstract

The invention relates to non-destructive testing means and can be used to monitor the condition of extended objects, such as pipelines under water. The purpose of the invention is to increase the reliability of the sensor when exposed to the external environment. The goal is achieved in that the sensor is equipped with a housing with an o-ring, a nozzle 4 for pumping air, a sealed cable outlet, a membrane control element for vacuum and glass bushings to secure the pre-treatment unit, and the simulator is located between the transducers and together with the pre-unit processing installed in the housing. 2 ill.

Description

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The invention relates to non-destructive testing means and can be used to monitor the condition of extended objects, e.g. pipelines.

An ultrasonic transducer for receiving acoustic emission signals is known, comprising a piezoelectric element, a protector, a support, a cable, a nut and a seal, while the protector is glued to the surface of the test object with glue.

The disadvantage of this converter is its low reliability due to the possible impact of the external environment.

A prototype of the invention is a sensor for detecting acoustic emission signals, comprising two transducers and a simulator of acoustic emission signals, as well as a pre-processing unit.

The purpose of the invention is to increase the reliability of the sensor when exposed to an external environment. °

This goal is achieved in that the sensor for recording acoustic emission signals, comprising two transducers and a simulator of acoustic emission signals, a preprocessing unit, is equipped with a housing with an o-ring seal, nozzles for pumping air, a sealed cable outlet, a membrane control element for vacuum and glass passage insulators for attaching the pre-treatment unit, the simulator is placed between the converters and together with the pre-processing unit is installed in the housing.

Figure 1 shows a sectional view of the sensor; figure 2 is the same, a top view when installed on the pipe.

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The sensor comprises a housing 1. Together with an annular seal 2 made of rubber and laid between the housing 1 and the surface of the pipe 3, a vacuum is applied to securely mount anywhere in the pipe, which is created in the space between the housing and the surface area to which it is attached. Evacuation is accomplished by connecting a vacuum pump to the nozzle 4 for pumping air. Vacuum control after air evacuation is carried out using the membrane element of vacuum control 5. If vacuum does not decrease, the nozzle 4 is pressed and sealed. The output cable 6, which is led through a sealed terminal in the form of a seal 7, is attached to the housing 1 through an eyelet 8 and a leash 9 attached to it to the sleeve 10. The device has a sealing seal 11 of the backup cable outlet 6. The acoustic emission transducer 12, the acoustic noise transformer 13 and the acoustic emission signal simulator in the form of a calibration emitter 14 are fixed at an equal distance from each other to ensure acoustic contact between the pipe surface and the acoustic element. The transducers 12, 13 and the emitter 14 are connected to the electronic components of the pre-processing unit on the board 15. The electrical terminals from the board 15 are attached to the cover 16 using glass bushings 17. The top cover 16 is used to seal the cable outlet compartment.

The operation of the sensor is as follows.

On the surface of the pipe 3, previously cleared of all types of corrosion, an annular seal 2 is glued to the sealant, laid in the shape of the housing 1. Inside the housing, a limited seal

A sensor for recording acoustic emission signals, comprising two transducers and a simulator of acoustic emission signals, a pre-processing unit, characterized in that, in order to increase the reliability of the sensor when exposed to an external shaper 2, transducers 12, 13 and emitter 14 are fixed. 1 is applied to the seal 2, pressed tightly to the surface and the vacuum pump is connected to the nozzle 4. Air is pumped out from the cavity of the housing 1. At the same time, the presence or absence is checked e vacuum. The conclusions of the cable 6 can be located both on the left and on the right side. At the same time, a plug is placed on the other sealing seal (7 or 11). The bushing 10 and the leash 9 serve to prevent damage to the cable terminals under mechanical stress. After checking the reliability of sealing, the entire sensor can be coated with an anti-corrosion sealing layer, for example, waterproofing bitumen mastic. The arrival of acoustic emission signals is detected by sensors 12 and 13. Then this information is processed by the elements of the pre-processing unit on the acoustic board 15 and is output in encoded form to the cable 6, which is connected

the other end to the recorder. Calibration emitter 14 automatically checks for acoustic contact of transducers 12 and 13.

Long-term operation of the sensor at an existing facility does not reduce the reliability of its operation for the following reasons. Due to the lack of air under the housing, the stability is significantly increased.

converters 12, 13 and emitter 14 in time. There are no aggressive components on the pipe surface that can adversely affect the operation of all sensor elements. Due to evacuation, a significant force of attraction of the sensor housing to the pipe occurs. This leads to reliable mechanical fixation of the housing ..:.

dy, it is equipped with a housing with an o-ring, a pipe for pumping air,

with a sealed cable outlet, a vacuum control membrane element and glass bushings for fastening the pre-treatment unit, the simulator is placed between the converters and together with the pre-processing unit is installed in the housing.

FIG. i