A Method of Controlling Bolt Pretightening Force Based on Axial Force and Elongation

A technology of bolt pre-tightening force and elongation, which is applied in non-electric variable control, mechanical pressure/force control, control/adjustment system, etc. question

Active Publication Date: 2021-05-18
中国大唐集团新能源科学技术研究院有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Among them, the bolt pre-tightening force is insufficient, resulting in loose bolts, excessive vibration of parts or equipment, and shear fracture of bolts under long-term service, resulting in a large proportion of major accidents.
The reason, first, is that the quality of the bolt itself is not good enough, and there are problems in the design and manufacturing process; secondly, the pre-tightening force of the bolt is insufficient during the installation and maintenance process, and the vibration caused by the operation process

Method used

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  • A Method of Controlling Bolt Pretightening Force Based on Axial Force and Elongation
  • A Method of Controlling Bolt Pretightening Force Based on Axial Force and Elongation
  • A Method of Controlling Bolt Pretightening Force Based on Axial Force and Elongation

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Embodiment Construction

[0025] The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0026] This embodiment provides a method for controlling the pretightening force of bolts based on axial force and elongation, including:

[0027] When the bolt is fastened for the first time, the acoustic time difference between the free state and the fastened state of the bolt is measured by ultrasonic waves, the elongation of the bolt is calculated based on the acoustic time difference, and the bolt pretightening force is obtained according to the elongation, so as to calculate the bolt pretightening force precise control;

[0028] For in-service bolts, based on the linear relationship between the propagation time of ultrasonic transverse waves and longitudinal waves i...

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Abstract

The invention relates to a method for controlling the pretightening force of bolts based on axial force and elongation, comprising: when the bolts are fastened for the first time, measuring the acoustic time difference between the free state and the fastened state of the bolt through ultrasonic waves, and calculating the bolt based on the acoustic time difference The elongation of the bolt is obtained according to the elongation, so as to accurately control the bolt pre-tightening force; for the bolts in service, based on the relationship between the time of ultrasonic transverse wave and longitudinal wave propagating in the bolt and the axial stress of the bolt The linear relationship can be used to obtain the residual pre-tightening force of the bolts to determine whether it is necessary to re-tighten the bolts in service. The invention can accurately measure the pre-tightening force of the bolt when it is fastened for the first time and the residual pre-tightening force of the bolt in service, so as to achieve the purpose of accurately controlling the pre-tightening force of the bolt.

Description

technical field [0001] The invention belongs to the technical field of wind power, and in particular relates to a method for controlling the pretightening force of bolts based on axial force and elongation. Background technique [0002] Bolted flange connection is a detachable static sealing connection structure widely used in wind power generation, pressure vessels, petrochemical equipment and pipelines. The main failure mode of the flange bolt connection system is leakage, and bolt preload is one of the important links to ensure that the connection surface does not leak. In the bolt connection, the bolt must be tightened during installation, that is, before the connection bears the working load, it is pre-acted by force. This pre-loaded force is called pre-tightening force. The purpose of pre-tightening is to enhance the reliability of the connection. and tightness to prevent gaps or relative slippage between the connected parts after loading. Therefore, in the flange bo...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01L5/24G05D15/01G01L5/00
Inventor 吴智泉张新刘蕴华吴春冯强孙涛杨佳霖
Owner 中国大唐集团新能源科学技术研究院有限公司
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