Vibrating wire type pressure sensor

Abstract

The invention provides a vibrating wire type pressure sensor comprising a shell, a stress membrane, a force transmission piston, a piston cylinder body, a vibrating wire, a vibrating wire clamping device, a magnetic coil and a force transmission piston. The stress membrane is a circular membrane; a dowel bar is arranged in the center of one side of the stress membrane and a convex block is arranged in the center of the other side of the stress membrane; and a stress membrane shell with the same shape as the shell is arranged outside the stress membrane. The two ends of the stress membrane shell are connected with the shell and the piston cylinder body respectively. A hydraulic cavity communicated with the piston cylinder body is formed in the force transmission piston at one side of the dowel bar of the stress membrane; a free end of the dowel bar is directly connected with the force transmission piston through the bottom of the piston cylinder and the piston cavity. The cavity openingof the hydraulic cavity is formed in the outer end face of the force transmission piston; and a flexible contact film making contact with a measured object is arranged at the cavity opening of the hydraulic cavity in a sealed mode. The vibrating wire is fixed on the convex block. Therefore, the pressure measurement precision is improved; the performance is stable and reliable; and the vibrating wire type pressure sensor is suitable for measurement of liquid pressure, internal forces of concrete and rock-soil bodies, and an interface contact pressure.

Description

technical field [0001] The invention belongs to the technical field of civil engineering detection, and relates to a rock-soil pressure detection instrument, in particular to a vibrating wire pressure sensor. Background technique [0002] Due to the advantages of high accuracy, reliable performance, long life, convenient data acquisition, simple manufacture and low cost, vibrating wire sensors have been widely used in geotechnical engineering. Vibrating wire sensors mainly include strain gauges, displacement gauges, piezometers, steel bar gauges, pressure cells and earth pressure gauges, etc. These sensors obtain the strain of the string by collecting the frequency of the vibrating wire, and obtain the displacement, deformation and stress. The main components of the vibrating wire pressure sensor include vibrating wires, deformable membranes, soft iron, magnets and exciters composed of coils. The deformable membrane is a metal thin circular plate fixed around it, the vibra...

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Problems solved by technology

[0003] The vibrating wire pressure sensor mainly has the following types. One is to directly introduce liquid to the side of the deformable membrane, and the deformable membrane is deformed under the action of liquid pressure. In this way, the side wall of the deformable membrane cavity is deformed by the liquid pressure, which affects the deformation of the deformable membrane. The uniformity and small range are suitable for measuring liquid pressure, such as osmometer; the second is to use the piston and liquid to transmit to the deformable membrane multiple times. And there are defects in the first method; the third is to use the force transmission pad to act on the middle part of the deformable membrane with the pressure of the measured object. In this way, the force transmission pad directly acts on the middle part of the force transmission membrane, and the force transmission pad and the deformation membrane are connected If it is a plane, the contact area will gradually decrease with the increase of pressure. If the contact end is a hemisphere, the contact area will gradually increase with the increase of pressure. The fourth is that the steel plate deformed by the pressure acting on the shell drives the base of the vibrating wire fixed on the steel plate to displace, thereby changing the length of the steel string. This method of force transmission using steel plate deformation will cause a certain loss of pressure. The measured The pressure is the average force on the steel plate surface, such as earth pressure gauge (box), anchor cable dynamometer

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