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CN-120521780-B - Pressure sensing device and method based on laser interference

CN120521780BCN 120521780 BCN120521780 BCN 120521780BCN-120521780-B

Abstract

The invention discloses a pressure sensing device and a method based on laser interference, which relate to the technical field of pressure sensing and comprise a laser driver, a tunable laser, a polarization maintaining coupler, a coherent coupler and a three-port single coupler, wherein an output end of the tunable laser is connected with an input end of the polarization maintaining coupler, a light beam generated by the laser driver is divided into two paths by the polarization maintaining coupler, the relation between coherent beat frequency and light path is obtained by utilizing a laser coherence principle, the change of the light path depends on the change intensity of external pressure received by a pressure strain gauge, then a pressure value can be obtained, and the sensor can be used for manufacturing an automatic metering tank for liquid ingredients because of high measurement precision.

Inventors

  • SUN XIAORONG
  • ZHANG AIAI

Assignees

  • 逸顿机电科技(上海)有限公司

Dates

Publication Date
20260508
Application Date
20240221

Claims (7)

  1. 1. The pressure sensing device based on laser interference comprises a laser driver (1), a tunable laser (2), a polarization maintaining coupler (3), a coherent coupler (4) and a three-port single-phase coupler (5), wherein an output end of the tunable laser (2) is connected with an input end of the polarization maintaining coupler (3), a light beam generated by the laser driver (1) is divided into two paths through the polarization maintaining coupler (3), one path of reference path optical fiber (16) is transmitted to a first input end of the coherent coupler (4), the other path of measurement path is connected with a 1 port of the three-port single-phase coupler (5), a2 port of the three-port single-phase coupler (5) is connected with the pressure detector (6), a3 port of the three-port single-phase coupler (5) is connected with a second input end of the coherent coupler (4), the pressure detector (6) generates a measurement path output to the coherent coupler (4), one path of the light beam is transmitted to a first input end of the coherent coupler (4), the other path of the pressure detector is connected with a2 port of the three-port single-phase coupler (5) is connected with a second input end of the coherent coupler (4), the pressure detector (7) is connected with a shell (8), the pressure detector (10) is connected with an inductive shell (11), the device comprises a beam shaper (12) and a reflecting mirror (13), wherein the pressure sensing elastic piece (9) is in direct contact with liquid, the polarization maintaining coupler (3) is used for distributing 6:4 power, a reference path is used for distributing 40% power, a measurement path is used for distributing 60% power, the coherent coupler (4) is used for distributing 50:50 light, a shell (10) and the pressure sensing elastic piece (9) are integrated, and the shell (10) is used for supporting a mechanical structure of a measurement cavity (11) formed by an outer cable shell (15), the beam shaper (12), the reflecting mirror (13) and the pressure sensing elastic piece (9).
  2. 2. A pressure sensing device based on laser interference according to claim 1, characterized in that the outer cable shell (15) is a mechanical structure for mounting armoured cables.
  3. 3. A pressure sensing device based on laser interference according to claim 1, characterized in that the reflecting mirror (13) connected to the pressure sensing spring plate (9) is fixed to the measuring cavity (11), the beam shaper (12) for receiving and transmitting laser is set in the reflecting mirror, the laser is emitted from the beam shaper (12), and beam reflection is formed between the end face of the beam shaper (12) and the surface of the reflecting mirror (13).
  4. 4. A pressure sensing device based on laser interferometry according to claim 1, characterized in that the measuring chamber (11), the housing (10) and the pressure sensitive dome (9) are arranged at the inlet end of the optical fiber (14) of the pressure detector (6).
  5. 5. A pressure sensing device based on laser interferometry according to claim 1, characterized in that one port of the three-port single-port coupler (5) is connected to the laser 60% output of the polarization maintaining coupler (3).
  6. 6. A pressure sensing device based on laser interferometry according to claim 1, characterized in that the three-port single coupler (5) has an optical path of 1-2-3-port, whereas the beam is isolated and cannot flow in reverse.
  7. 7. The pressure sensing method based on laser interference is characterized in that the output end of the coherent coupler (4) passes through the photoelectric detector (7) to obtain beat frequency signals of a reference path and a measuring path, the beat frequency of the reference path and the measuring path is calculated to obtain pressure values in the pressure detector (6), the frequency difference between reference light and measuring light is demodulated, the frequency difference between the reference path and the measuring path is correspondingly changed to obtain optical path change, and when the pressure is changed, the pressure sensing spring (9) knows pressure change, so that the distance between the beam shaper (12) and the reflecting mirror (13) is changed, the time for generating return light in the pressure detector (6) by laser is changed, and the pressure value of the pressure sensing spring (9) when the external pressure is changed is obtained.

Description

Pressure sensing device and method based on laser interference The invention relates to the technical field of pressure sensing, in particular to a pressure sensing device and method based on laser interference. Background For the measurement of liquid, liquid canning (container) weighing or a liquid level meter is often adopted, the precision is low and complicated, for example, in industry, liquid ingredients (chemical industry, pharmaceutical industry and the like) are mostly selected to be liquid canning and weighing, and then the liquid is poured into the container, so that the liquid canning and weighing device occupies large area, the manpower for inputting equipment is large, the precision often cannot meet the requirement, and the product quality is affected. The method limits the application of the automatic control technology, influences the development of related industrial departments, and aims to provide the pressure sensor which is high in measurement precision and is mainly used for measuring liquid and gas and is used for operating a cylinder list aiming at the defects in the prior art. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a pressure sensing device and a pressure sensing method based on laser interference, which solve the problem of low measurement precision of the prior device. The pressure sensing device based on laser interference comprises a laser driver, a tunable laser, a polarization maintaining coupler, a coherent coupler and a three-port single coupler, wherein an output end of the tunable laser is connected with an input end of the polarization maintaining coupler, a light beam generated by the laser driver is divided into two paths through the polarization maintaining coupler, one path of reference path is transmitted to a first input end of the coherent coupler, the other path of reference path is connected with a 1-port of the three-port single coupler, a 2-port of the three-port single coupler is connected with the pressure detector, a 3-port of the three-port single coupler is connected with a second input end of the coherent coupler, the pressure detector generates a measuring path to be output to the second input end of the coherent coupler, the output end of the coherent coupler is connected with the light detector and is connected with the upper computer demodulation system, the sensing pressure detector comprises a pressure detector, the sensing path comprises a pressure-sensitive shell, a pressure-side reflector, a pressure-sensitive shell and a pressure-sensitive shell, a pressure-side reflector, a pressure-wave-absorbing shell and a pressure-absorbing shell, wherein the pressure-absorbing shell and the pressure-absorbing shell is in a pressure-absorbing shell, the pressure-absorbing shell is formed by 50%, and the pressure-absorbing shell is directly in a pressure-absorbing shell, and the pressure-absorbing shell is formed by 50% and the pressure-absorbing shell. Preferably, the outer cable casing is a mechanical structure for installing an armoured cable. Preferably, the reflecting mirror connected with the pressure sensing elastic piece is fixed in the measuring cavity, the beam shaper for receiving and transmitting laser is arranged in the reflecting mirror, the laser is emitted from the beam shaper, and light beam reflection is formed between the end face of the beam shaper and the surface of the reflecting mirror. Preferably, the measuring cavity, the housing and the pressure sensing spring are arranged at an optical fiber inlet end of the pressure detector. Preferably, one port of the three-port single-port coupler is connected with the laser 60% output end of the polarization maintaining coupler. Preferably, the optical path of the three-port single coupler is 1-2-3, and the light beam is isolated and cannot flow reversely. The pressure sensing method based on laser interference includes that the output end of a coherent coupler obtains beat frequency signals of a reference path and a measuring path through a photoelectric detector, the beat frequency of the reference path and the measuring path is calculated to obtain pressure values in the pressure detector, the frequency difference between the reference light and the measuring light is demodulated, the frequency difference between the reference path and the measuring path is changed to obtain the change of an optical path, when the pressure is changed, the pressure sensing elastic sheet knows the pressure change, the distance between the beam shaper and a lens is changed, the time of laser generating return light in the pressure detector is changed, and therefore the pressure value of the pressure sensing elastic sheet when the external pressure is changed is obtained. Advantageous effects The invention provides a pressure sensing device and a method based on laser interference, which have the advantages that the invention utilizes the laser coherence princip