CN101334322B - Method for measuring temperature, stress-strain and vibration of high-temperature double-layer pipeline - Google Patents

Abstract

A method for measuring temperature, stress-strain, and vibration of a high-temperature double-layer pipeline. The thermocouple and strain gauge are spot-welded at the position to be measured in the inner tube of the double-layer pipe. The accelerometer is installed at the position to be measured in the inner tube. The thermocouple is The wires are directly connected to the interface box, the strain gauge is connected to the interface box through the bridge box and the static strain gauge, the accelerometer is connected to the interface box through the signal conditioner, and the data collected by the interface box is transmitted to the data acquisition and analysis system, wherein, the The leads of primary instruments such as thermocouples, strain gauges, and accelerometers are led out through the mouth of the nozzle welded to the outer tube, and the leads of the nozzle of the nozzle are sealed by welding. The leads of thermocouples, strain gauges, and accelerometers are led out through a nozzle welded to the outer tube, which solves the problem of lead sealing. The measurement method is simple and practical.

Description

Measurement method of temperature, stress-strain and vibration of high-temperature double-layer pipeline

technical field

The invention belongs to the technical field of physical measurement, and in particular relates to a temperature, stress-strain and vibration measurement method of a pipeline.

Background technique

The sodium-cooled fast reactor uses sodium as the coolant, and its main heat transfer system pipe temperature is as high as 515°C, which is much higher than the main pipe temperature of the pressurized water reactor nuclear power plant. Among them, part of the pipe section of the main cooling system of the secondary circuit is a double-sleeve structure, and the maximum working temperature is 495°C. The potential cause of failure is excessive stress, displacement, creep and vibration of the pipe. Temperature, stress-strain, and vibration measurements are carried out during start-up and operation, so that possible defects in the system piping can be found in a timely and effective manner. Through predictive maintenance, the failure hidden dangers that affect the safe operation of the system piping can be eliminated in the bud, and the safety of the reactor can be improved. sex and economy.

At present, the temperature, stress-strain, and vibration measurement technologies for ordinary pipelines are relatively mature at home and abroad, but there is no relevant literature on the measurement of high-temperature double-layer pipelines, especially the measurement technology of high-temperature double-layer pipelines in radioactive environments. .

Contents of the invention

(1) Purpose of the invention

The invention aims at the deficiencies of the prior art and provides a relatively practical method for measuring the temperature, stress-strain and vibration of a high-temperature double-layer pipeline.

(2) Technical solutions

To achieve the above object, the present invention provides the following technical solutions.

A method for measuring temperature, stress-strain, and vibration of a high-temperature double-layer pipeline. The thermocouple and the strain gauge are spot-welded on the position to be measured in the inner tube of the double-layer pipeline, the accelerometer is installed on the position to be measured in the inner tube, and the position of the thermocouple is The wire is directly connected to the interface box, the strain gauge is connected to the interface box through the bridge box and the static strain gauge, the accelerometer is connected to the interface box through the signal conditioner, and the data collected by the interface box is transmitted to the data acquisition and analysis system. The key is that the lead wires of the thermocouple, the strain gauge and the accelerometer are drawn out through the nozzle welded on the outer tube, and are sealed by welding after the nozzle leads are connected.

In order to minimize the attenuation of the measurement signal and ensure the personal safety of the measurement personnel, the above-mentioned secondary instruments are placed near the measurement point, while the data acquisition and analysis system is set in a non-radioactive area, such as a control room.

(3) Implementation effect

Lead wires of thermocouples, strain gauges and accelerometers are led out through a nozzle welded on the outer tube, which solves the problem of lead wire sealing. The measurement method is simple and practical.

Description of drawings

Figure 1 Schematic diagram of the measurement system;

Figure 2 Schematic diagram of the structure of the takeover lead wire.

Among them, 1. Inner tube; 2. Primary instrument; 3. Outer tube; 4. Connector; 5. Lead wire; 6. Secondary instrument.

Detailed ways

The technical solution of the present invention will be further elaborated below in conjunction with the accompanying drawings.

In this embodiment, the temperature, stress-strain and vibration of the inner tube of the main pipeline of the secondary circuit of the sodium-cooled fast reactor are measured. The finite element thermal stress analysis results show that the outer surface of the straight pipe is mainly axial stress, and the hoop tensile stress is basically equal to zero, but sometimes there is hoop shear stress, and hoop strain gauges cannot measure the hoop shear stress, so the outer surface of the straight pipe is measured The point mainly uses two axial strain gauges arranged symmetrically at 180 degrees to measure the axial tensile stress and bending stress of the straight pipe. For straight pipes with large shear stress, measure the maximum principal stress after installing and installing strain gauges with an included angle of 45 degrees to the axial direction. For the bent pipe, due to the complexity of the principal stress direction, three strain gauges are arranged to form a 90-degree right-angle strain rosette. The vibration measurement point is located in the straight pipe section after the second elbow after the outlet of the main pump. The pipeline vibration measurement accelerometer is directly installed on the pipeline with a non-destructive connection method, and the pipeline vibration measurement point consists of three accelerometers to form a three-way measurement point. In addition, the high-temperature strain gauge installed on the pipeline can also measure the vibration stress and stress response spectrum of the pipeline, and connect the dynamic strain gauge to the strain gauge on the pipeline with severe vibration to measure the dynamic stress amplitude.

Refer to Figure 1, a high-temperature double-layer pipeline temperature, stress-strain, vibration measurement system, mainly including primary instrument 2, secondary instrument 6 and data acquisition and analysis system. Check and check primary instruments 2 such as high-temperature strain gauges, thermocouples, and counters before installation, and then spot-weld and install strain gauges, thermocouples, and counters at the predetermined measurement positions of the inner tube 1 . The lead wires 5 of strain gauges, thermocouples and counters are drawn out from the mouth of a connection tube 4 through the outer wall. The connecting pipe 4 and the outer pipe 3 of the main pipe are welded by penetration welding, and the distance from the inner pipe to be tested is 100-300mm. At the melting temperature of the wire 5, the wire 5 will not be damaged. After the wire 5 is drawn out, the wire of the thermocouple is directly connected to the interface box, the strain gauge is connected to the interface box through the bridge box and the static strain gauge, the accelerometer is connected to the interface box through the signal conditioner, and the data collected by the interface box is transmitted to the data acquisition unit. analysis system. In order to minimize the attenuation of the signal, the secondary instrument is placed in the radiation environment near the measurement point, and the data acquisition and analysis system is set in the control room.

Claims (3)

1. high-temperature double-layer pipe temperature, stress-strain, vibration measurement method, be with thermopair, the foil gauge point is welded in the position to be measured of pipe (1) outer wall in the double-skin duct, accelerometer is installed in the position to be measured of interior pipe (1) outer wall, the lead of thermopair directly connects with interface box, foil gauge is by the bridge box, statical strain indicator connects with interface box, accelerometer connects with interface box by the suitable instrument of transferring of signal, the data transmission that interface box is gathered is given data acquisition and analysis system, it is characterized in that: described thermopair, foil gauge, the mouth of the adapter (4) of the lead-in wire (5) of these primary instruments of accelerometer (2) by being welded on outer tube (3) is drawn, and passes through welded seal after taking over the mouth lead-in wire of (4).

2. high-temperature double-layer pipe temperature according to claim 1, stress-strain, vibration measurement method is characterized in that: the straight tube outside surface adopts two axial foil gauges of 180 degree symmetric arrangement to measure straight tube axial tension stress and bending stress; For the bigger straight tube of shear stress, measure major principal stress behind the foil gauge of additional installation and axial angle 45 degree; Bend pipe adopts three foil gauges to be arranged to 90 degree rectangular rosettes and measures principle stress.

3. high-temperature double-layer pipe temperature according to claim 1, stress-strain, vibration measurement method, it is characterized in that: described bridge box, statical strain indicator, suitable instrument, these secondary instruments of interface box (6) transferred of signal are placed near the measurement point, and data acquisition and analysis system is arranged on the cold area.

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