Water turbine top cover bolt looseness detection system and design method of detector

Abstract

The invention discloses a water turbine top cover bolt looseness detection system and a design method of a detector. The detection system comprises a strain type pressure detector, a wireless transmitter and a diagnosis alarm unit, the strain type pressure detector adopts a gasket type pressure sensor, a shear beam structure is formed at the position of a transition groove through a gasket body, and forces borne by an inner ring face and an outer ring face act on the two ends of the shear beam respectively, so that axial deformation of the shear beam is caused, and a relation is established between bolt load changes and axial displacement deformation; a strain gauge generates a strain effect, then real-time quantitative detection of pre-tightening force is achieved, the design method of the detector is based on the physical characteristics of a fastening bolt and the assembly requirement of the fastening bolt, meanwhile, the size of the gasket body which ensures that a flange face cannot cause dent deformation is calculated, the sensitivity of looseness detection of the fastening bolt is high, and feedback is timely; and through a wireless transmitter and the diagnosis alarm unit, manual detection and analysis alarm are not needed.

Description

technical field [0001] The invention belongs to the technical field of bolt looseness detection for water pump turbines, and in particular relates to a water turbine top cover bolt looseness detection system and a design method for a detector. Background technique [0002] The pump turbine is an important equipment of the pumped storage power station. The runner rotates clockwise as a water turbine to realize the conversion of water energy to mechanical energy, and is combined with the generator to realize the conversion of mechanical energy to electrical energy; the runner rotates counterclockwise as a water pump to realize mechanical energy. Conversion to water energy. The water pump turbine unit is composed of seat ring, top cover, bottom ring, water turbine, water guide bearing, main shaft seal, guide vane and servomotor. The connection between the top cover and seat ring is fixed by 80 bolts, and the specification is M120*6 , That is, the tooth diameter is 120mm, the t...

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Problems solved by technology

[0007] For the above method 1, the advantage is that it is easy to install, but because the pre-tightening force of the top cover seat ring is 525 MPa, when the bolts are loose, the pre-tightening force will reach tens to hundreds of MPa, and the thread of the screw and the thread of the nut fit tightly. Displacement occurs in the axial direction of the screw, and the angular displacement of the screw is very small, basically less than 5°, which is difficult to detect by the sensor

[0008] For the second method above, the advantage is that the axial displacement of the screw can be quantitatively measured, and the pre-tightening force can be converted according to the axial displacement. However, for the use of optical fiber sensors, the premise is that the bolts and screws need to reserve observation holes, and the actual situation is A pump turbine has 80 bolts, of which only 4 bolts are reserved for observation holes, which is difficult to meet the monitoring requirements of all 80 bolts

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