A method for monitoring flange connection bolt looseness

Abstract

The invention provides a method for monitoring the looseness of flange connection bolts. First, a split displacement sensor is installed at the flange connection, and connected with a data acquisition instrument or an edge computing gateway; when abnormal conditions such as loosening and fracture occur, the high The precision electromagnetic induction chip captures changes in the magnetic field, the temperature sensor chip collects ambient temperature data, and the vibration sensor chip samples external vibration signals and converts them into level signals. All three signals are transmitted to the single-chip microcomputer; the single-chip microcomputer performs data processing on the received signals. Conversion, and then correct the displacement data based on the ambient temperature data and vibration data, and finally send the data to the data collector or edge computing gateway; the collector or edge computing gateway counts and analyzes the received data, and then judges the flange Whether the connecting bolts are loose, broken or other abnormal conditions. The monitoring method provided by the invention has the advantages of accurate monitoring results, stable and reliable operation, and low cost.

Description

technical field [0001] The invention relates to a split-type displacement sensor for gap monitoring, in particular to a method for monitoring flange connection bolt looseness based on the split-type sensor. Background technique [0002] Flange connection refers to a detachable connection consisting of flanges, gaskets and bolts connected to each other as a combined sealing structure. Flange connection structures are extremely common in the current industrial field and play a very important role. The bolts in the flange connection structure are subjected to tension and compression cycles under alternating loads. Under the action of alternating tension and compression loads, the plastic deformation of the thread leads to relaxation, which will lead to a decrease in the pre-tightening force of the bolt. If the pre-tightening force is too small, the connection will be unreliable, and phenomena such as vibration relaxation, leakage, and structural slippage will occur during work...

AI Technical Summary

Problems solved by technology

This work is time-consuming and labor-intensive, coupled with the multi-factor influence of personal subjective and objective aspects of the staff, it cannot guarantee that the problem of bolt looseness can be found and eliminated in time every time, so it is necessary to carry out online monitoring of bolt looseness

[0003] At present, there are usually three methods for monitoring bolt looseness: the first method is based on the measurement method of the gasket type force sensor, and a special force sensor is set on the bolt like a gasket, and the pressure of the sensor is the axial direction of the bolt. This method requires a special sensor according to the space and bolt size. The process is cumbersome and the cost is high. The second method is the ultrasonic method. This method calculates the elongation of the bolt according to the ultrasonic time and speed, and calculates it based on the axial stiffness of the bolt. The axial force of the bolt, this method needs to install a specific sensor on the bolt head; the third method is based on the camera technology to monitor whether the nut of the bolt connection pair rotates, if it occurs, it is loose

The first two methods need to monitor the pre-tightening force of each bolt, and each bolt needs to be processed or adopted. The process is complicated and the cost is high; the third method, in order to realize the monitoring of all bolts in the flange connection, Usually at least two high-precision cameras need to be installed, which has high requirements for the installation environment and high cost

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