CN205228702U - Optic fibre high pressure sensor based on F -P principle of interference - Google Patents

Abstract

The utility model provides an optic fibre high pressure sensor based on F -P principle of interference, including pressure inlet, pressure source joint, base, shell, optical cable water joint, sensing diaphragm, multimode fiber, SMA metal optic fibre lock pin, armor optic fibre overcoat. The beneficial effects of the utility model are that adopt stainless steel shell encapsulation form, make among its pressure sensing that can be applied to adverse circumstances such as ocean, oil well, passive light sensing anti -electromagnetic interference nature is strong, and only needs to supply power to the low -power light source, sensor signal passes through the low relevant interferometric method demodulation of polarization, and LAMP POWER's fluctuation does not have the influence to the demodulation, sensor structure is simple, easy maintenance, and the processing cost is low, high, the batch production of being convenient for of production efficiency.

Description

A kind of optical fiber high pressure sensor based on F-P principle of interference

Technical field

The utility model belongs to sensory field of optic fibre, especially relates to a kind of optical fiber high pressure sensor based on F-P principle of interference.

Background technology

In the high pressure engineering fields such as marine monitoring, oil, chemical industry, environmental pressure is important Contents for Monitoring, is directly connected to the precision of Monitoring Data, the safety of production environment, the quality of industrial products.

Widely used in existing technology is electronic pressure sensor, and this sensor exists problems such as being difficult to avoid noise and temperature drift problems, volume is large, the life-span is short, lay difficulty, maintenance cost is high.Fibre Optical Sensor has electromagnetism interference, electrical insulating property is good, corrosion-resistant, highly sensitive, lightweight, volume is little, shape variable, be convenient to the plurality of advantages such as multiplexing, be applicable to very much being applied in high pressure field of detecting, but at present not based on the optical fiber high pressure sensor under F-P principle of interference technology platform.

Summary of the invention

Problem to be solved in the utility model is to provide a kind of optical fiber high pressure sensor based on F-P principle of interference, optical fiber F-P pressure sensor is applied to high pressure field of detecting.This sensor electromagnetism interference, install convenient, cost is lower, is especially applicable to the pressure survey in the fields such as marine monitoring, oil, chemical industry.

For solving the problems of the technologies described above, the technical solution adopted in the utility model is:

Based on an optical fiber high pressure sensor for F-P principle of interference, it is characterized in that: sensor comprises pressure entrance, pressure source joint, base, shell, optical cable water joint, pressure-sensitive diaphragm, multimode optical fiber, SMA metal optical fiber lock pin, armored fiber optic overcoat; The side of SMA metal optical fiber lock pin and base is sealed by uniform application epoxide-resin glue, and underrun laser bonding connects; Pressure-sensitive diaphragm is the square diaphragm with cylindrical method amber microcavity, and is fixed by epoxy resin between SMA metal optical fiber lock pin, passes through the centering of polarization low coherence interference (FBG) demodulator observation signal quality assurance diaphragm and lock pin before fixing; The side of pressure source joint and base is sealed by uniform application epoxide-resin glue, and underrun laser bonding connects; All be threaded connection between base and shell, between shell and optical cable water joint; Optical fiber improves the serviceable life of sensor through armouring.

Pressure source joint, base, shell all adopt Stainless steel 316 L material, make sensors being operative in hyperbaric environment, and improve the corrosion resistance of sensor.

All be connected and sealed by epoxy resin sealant and laser bonding between pressure source joint, base, SMA metal optical fiber lock pin, realize the seal isolation to sensing unit, ensure that gas or liquid pressure source medium do not leak.Pressure source joint adopts GB screw thread, can be connected with pressure source or other Devices to tests easily.

Pressure-sensitive diaphragm adopts MEMS process technology, has the Pyrex glass of microcavity to carry out anode linkage monocrystalline silicon piece and corrosion, ensure that dimensional accuracy and the stability of sensing unit.

The advantage that the utility model has and good effect are: adopt Stainless Steel Shell packing forms, increase the range of sensor, and in the pressure making it can be applied to the rugged surroundings such as ocean, oil well detection; Sensor is passive light sensing, and electromagnetism interference is strong, and only needs light source power supply when using, and power consumption is low; Transducing signal by the demodulation of polarization low coherence interference method, the fluctuation of light source power on demodulation without impact; Sensor construction is simple, and easy to maintenance, processing cost is low, production efficiency is high, be convenient to batch production.

Accompanying drawing explanation

Fig. 1 is structural representation of the present utility model

Fig. 2 is vertical view of the present utility model

Fig. 3 is upward view of the present utility model

Fig. 4 is pressure-sensitive diaphragm structural drawing of the present utility model

Fig. 5 is sensing head cellular construction figure of the present utility model

Fig. 6 is embodiment system schematic of the present utility model

In figure:

1, pressure entrance 2, pressure source joint 3, base

4, shell 5, optical cable water joint 6, pressure-sensitive diaphragm

7, multimode optical fiber 8, SMA metal optical fiber lock pin 9, armored fiber optic overcoat

10, sensing silicon chip 11, vacuum F-P cavity 12, Pyrex substrate of glass

13, LED light source 14, three-dB coupler 15, simulating ocean environment head tank

16, this novel sensor 17, signal processing module 18, demodulating unit

19, line array CCD 20, polaroid 21, birefringent wedge

22, optical fiber ceramic lock pin 23, sensing head unit

Embodiment

As shown in Figure 1, 2, 3, a kind of optical fiber high pressure sensor based on F-P principle of interference of the utility model, comprises pressure entrance 1, pressure source joint 2, base 3, shell 4, optical cable water joint 5, pressure-sensitive diaphragm 6, multimode optical fiber 7, SMA metal optical fiber lock pin 8, armored fiber optic overcoat 9.

The side of SMA metal optical fiber lock pin 8 and base 3 is sealed by uniform application epoxide-resin glue, and underrun laser bonding connects; Pressure-sensitive diaphragm 6 is the square diaphragm with cylindrical method amber microcavity, and is fixed by epoxy resin between SMA metal optical fiber lock pin 8, passes through the centering of polarization low coherence interference demodulating unit 18 observation signal quality assurance diaphragm and lock pin before fixing; The side of pressure source joint 2 and base 3 is sealed by uniform application epoxide-resin glue, and underrun laser bonding connects; All be threaded connection between base 3 and shell 4, between shell 4 and optical cable water joint 5; Optical fiber improves the serviceable life of sensor through armouring.

Pressure source joint 2, base 3, shell 4, optical cable water joint 5 form the packaging shell of the utility model sensor; With reference to shown in Fig. 4, sensing silicon chip 10 and Pyrex substrate of glass 12 form pressure-sensitive diaphragm 6, between the two for corrode through MEMS technology the vacuum F-P microcavity 11 obtained through anode linkage; With reference to shown in Fig. 5, pressure-sensitive diaphragm 6 and metal optical fiber lock pin 8 are through epoxide-resin glue bonding formation sensing head unit.

The course of work of this example:

With reference to shown in Fig. 6, the utility model optical fiber high pressure sensor 16 is connected on the pressure interface of simulating ocean environment head tank 15 to be measured.When the pressure in head tank changes, pressure liquid medium in tank acts on pressure-sensitive diaphragm 6, and pressing sensing silicon chip 10 makes it elastic deformation occurs.Known according to Plate Theory, silicon chip deformation quantity and pressure change amount meet formula:

$\mathrm{\Δ}d=\frac{3}{16}\·\frac{(1-{\mathrm{\μ}}^2)-r^4}{E\·h^3}\·\mathrm{\Δ}P$

Namely silicon chip deformation quantity and pressure change amount linear.And silicon chip deformation quantity and F-P cavity chamber are grown also linear, therefore can determine that the F-P cavity chamber in certain moment is long by carrying out demodulation to light signal, and then draw the force value in head tank.

The light that white LED light source 13 sends, enters the utility model sensor 16 through three-dB coupler 14.Light is modulated through F-P cavity 11, and the reflected light with F-P cavity chamber long message enters demodulating unit 18 through three-dB coupler 14 again.Demodulating unit 18 adopts polarization type low coherence interference demodulation method, F-P cavity chamber long message is converted to the positional information on line array CCD 19.The electric signal that line array CCD 19 exports processes through signal processing module 17 again, demodulates force value now.

By the thickness of change sensing silicon chip 10 and the bottom surface radius of vacuum F-P cavity 11, can make the sensor being applicable to different pressures investigative range, range can be 0 ~ 30Mpa, 0 ~ 50Mpa, 0 ~ 70Mpa etc.By accurately controlling the manufactured size of pressure-sensitive diaphragm 6 and accurate demodulation method, high precision real-time pressure detection requirement can be met.

Above an embodiment of the present utility model has been described in detail, but described content being only preferred embodiment of the present utility model, can not being considered to for limiting practical range of the present utility model.All equalizations done according to the utility model application range change and improve, and all should still belong within patent covering scope of the present utility model.

Claims (1)

1. based on an optical fiber high pressure sensor for F-P principle of interference, it is characterized in that: described sensor comprises pressure entrance (1), pressure source joint (2), base (3), shell (4), optical cable water joint (5), pressure-sensitive diaphragm (6), multimode optical fiber (7), SMA metal optical fiber lock pin (8), armored fiber optic overcoat (9); The side of SMA metal optical fiber lock pin (8) and base (3) is sealed by uniform application epoxide-resin glue, and underrun laser bonding connects; Pressure-sensitive diaphragm (6) is the square diaphragm with cylindrical method amber microcavity, and fixed by epoxy resin between SMA metal optical fiber lock pin (8), pass through the centering of polarization low coherence interference (FBG) demodulator observation signal quality assurance diaphragm and lock pin before fixing; The side of pressure source joint (2) and base (3) is sealed by uniform application epoxide-resin glue, and underrun laser bonding connects; All be threaded connection between base (3) and shell (4), between shell (4) and optical cable water joint (5).