CN203587537U - Catalytic combustion type gas concentration meter based on optical fiber Bragg raster - Google Patents
Catalytic combustion type gas concentration meter based on optical fiber Bragg raster Download PDFInfo
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- CN203587537U CN203587537U CN201320730183.3U CN201320730183U CN203587537U CN 203587537 U CN203587537 U CN 203587537U CN 201320730183 U CN201320730183 U CN 201320730183U CN 203587537 U CN203587537 U CN 203587537U
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- China
- Prior art keywords
- optical fiber
- fiber bragg
- bragg raster
- heat conducting
- temperature measuring
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- 239000013307 optical fiber Substances 0.000 title claims abstract description 60
- 238000007084 catalytic combustion reaction Methods 0.000 title claims abstract description 19
- 238000010438 heat treatment Methods 0.000 claims abstract description 35
- 238000002485 combustion reaction Methods 0.000 claims abstract description 19
- 239000003054 catalyst Substances 0.000 claims abstract description 14
- 230000001681 protective effect Effects 0.000 claims abstract description 6
- 238000007747 plating Methods 0.000 claims description 17
- 239000000835 fiber Substances 0.000 claims description 15
- 238000004880 explosion Methods 0.000 claims description 12
- 238000002955 isolation Methods 0.000 claims description 12
- 238000009529 body temperature measurement Methods 0.000 claims description 10
- 239000003822 epoxy resin Substances 0.000 claims description 4
- 229920000647 polyepoxide Polymers 0.000 claims description 4
- 238000005259 measurement Methods 0.000 abstract description 4
- 239000011248 coating agent Substances 0.000 abstract 3
- 238000000576 coating method Methods 0.000 abstract 3
- 230000000694 effects Effects 0.000 description 6
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 238000001514 detection method Methods 0.000 description 3
- 238000005538 encapsulation Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 238000012544 monitoring process Methods 0.000 description 3
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 3
- 230000003197 catalytic effect Effects 0.000 description 2
- 238000006073 displacement reaction Methods 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000005489 elastic deformation Effects 0.000 description 1
- 238000010892 electric spark Methods 0.000 description 1
- 239000012777 electrically insulating material Substances 0.000 description 1
- 239000003532 endogenous pyrogen Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 239000005350 fused silica glass Substances 0.000 description 1
- 108010052620 leukocyte endogenous mediator Proteins 0.000 description 1
- 238000013178 mathematical model Methods 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
Images
Abstract
The utility model relates to a catalytic combustion type gas concentration meter based on an optical fiber Bragg raster, and belongs to the technical field of photoelectronic measurement. The catalytic combustion type gas concentration meter comprises a temperature measuring device, a gas combustion device and an explosive-proof device, wherein the temperature measuring device comprises the optical fiber Bragg raster, a cylindrical heat conducting wall and an optical fiber leading out line. The optical fiber Bragg raster is packaged as an optical fiber temperature measuring contact by virtue of a protective cover, and the optical fiber temperature measuring contact is attached to an opened inner hole at the fixed radius of the cylindrical heat conducting wall. The gas combustion device comprises a catalyst layer, a coating film of a heating resistor, a heating source lead and an electrode, wherein the catalyst layer is paved on the outer surface of the coating film of the heating resistor, and the coating film of the heating resistor is located on the outer surface of the heat conducting wall. The explosive-proof device comprises an explosive-proof hood and a base, wherein the explosive-proof hood is embedded into the temperature measuring device on the base and covers the gas combustion device. The catalytic combustion type gas concentration meter provided by the utility model is simple in structure, convenient to use and strong in interference resistance at the same time.
Description
Technical field
The utility model relates to a kind of catalytic combustion type gas concentration meter based on optical fiber Bragg raster, belongs to photoelectron field of measuring technique.
Background technology
In flammable explosive gas environment, gas detection sensor is in occupation of critical role, and exceeding standard of combustable gas concentration has a strong impact on staff's personal safety and safety in production generation.Study for a long period of time and show, the Real-Time Monitoring of gas concentration sensor has determined the operational reliability of safety in production to a great extent.Gas sensor timely in reaction environment the concentration of inflammable gas or damage all can make safe less than guarantee, because the combustable gas concentration serious accident causing that exceeds standard at home and abroad all occurs repeatedly.
The detection of inflammable gas is generally used to catalytic combustion type sensor, and it can regard the calorimeter of a miniaturization as, and its detection principle does not have large variation within decades.Catalytic combustion type sensor belongs to pyrostat, is the thermal effect principle of utilizing catalytic combustion to produce.Its inner structure is that detecting element and compensating element, are composed of measuring bridge, if when inflammable gas exists, under the acting in conjunction of detecting element carrier surface and catalyzer, there is flameless burning in inflammable gas, bed temperature is with regard to corresponding rising, thereby also can there is corresponding change in the platinum resistance resistance by its inside, and compensating element, is temperature-resistant, and electric bridge has just lost balance, by circuit, measured the variation of resistance, and export a voltage signal being directly proportional to combustable gas concentration.So, as long as can measure detecting element resistance size, just can calculate the concentration of gas to be measured.In whole measuring process, catalyzer is not consumed, even during well below LEL, also can there is catalyst combustion reaction on this electric bridge in gas concentration to be measured.But that uses in the method is electric signal, be subject to the impact of electromagnetic interference (EMI).
Summary of the invention
The utility model provides a kind of catalytic combustion type gas concentration meter based on optical fiber Bragg raster, for solving ignite inflammable gas in environment of high temperature, has the problem of potential safety hazard and is subject to the problem of the impact of electromagnetic interference (EMI).
The technical solution of the utility model is: a kind of catalytic combustion type gas concentration meter based on optical fiber Bragg raster, comprises temperature measuring equipment, gas combustion apparatus and explosion isolation device; Described temperature measuring equipment comprises optical fiber Bragg raster 1, cylindrical heat conducting wall 7, fiber pigtail 9, wherein optical fiber Bragg raster 1 is encapsulated into optical fiber temperature-measurement contact by protective casing, optical fiber temperature-measurement contact sticks in cylindrical heat conducting wall 7 endoporus that radii fixus place has held successfully, and fiber pigtail 9 is drawn by the fairlead being positioned on explosion isolation device base 6; Described gas combustion apparatus comprises catalyst layer 3, heating resistor film plating layer 4, heating source lead-in wire 5, electrode 8, wherein catalyst layer 3 applies the outside surface at heating resistor film plating layer 4, heating resistor film plating layer 4 is positioned at cylindrical heat conducting wall 7 outside surfaces, and the heating source of drawing from electrode 8 lead-in wire 5 is connected with external power source; Described explosion isolation device comprises flame proof cover 2, base 6, and wherein flame proof cover 2 is by the temperature measuring equipment and the gas combustion apparatus cover that are embedded on base 6.
Described cylindrical heat conducting wall 7 seals by epoxy resin with the junction of fiber pigtail 9.
Principle of work of the present utility model is:
Optical fiber Bragg raster 1 is become to optical fiber temperature-measurement contact after protective casing encapsulation; optical fiber temperature-measurement is lifted one's head and sticked in the endoporus that cylinder heat conducting wall 7 held successfully; and apply heating resistor film plating layer 4 at the outside surface of cylinder; at the outside surface of heating resistor film plating layer 4, apply catalyst layer 3, heating source lead-in wire 5 is connected to external power source.Open after external power source, heating resistor film plating layer 4 heats, for the burning of inflammable gas provides ignition temperature.
The heat difference producing during the gaseous combustion of variable concentrations, cylindrical heat conducting wall 7 in temperature measuring equipment will produce different Temperature Distribution under different thickness, different temperature can cause that the wavelength of temperature measuring optical fiber Bragg grating 1 produces different side-play amounts, by the measurement of the wavelength shift to temperature measuring optical fiber Bragg grating 1, can realize the measurement to combustable gas concentration to be measured.
Mathematics model analysis of the present utility model is as follows:
Temperature increment (temperature increment of the heating resistor film) Δ of cylindrical wall outside surface
tbe directly proportional to the thermal value of gaseous combustion,
In formula,
qthermal value during for gaseous combustion;
c p for heating resistor thermal capacitance;
for catalytic performance constant; Δ
hfor gas fuel burning heat;
cfor gas percentage composition to be measured.
The temperature of cylindrical wall outside surface changes, and according to cylindrical wall conduction model, the optical fiber grating temperature that is positioned at cylindrical wall radii fixus place changes.Cylindrical wall conductive structure is referring to accompanying drawing 2, and conduction model is as follows:
One long hollow cylinder, inside and outside wall temperature is respectively
t w1
with
t w2
, interior external radius is
r 1with
r 2, there is no endogenous pyrogen.By the Heat Conduction Differential Equations abbreviation of circular cylindrical coordinate, one dimension is the differential equation of heat conduction radially:
（2）
Conduction velocity by arbitrary annular surface can be expressed as:
（3）
In formula,
for coefficient of heat conductivity,
afor radius
rthe annular heat-conducting area at place.
The thermal conduction rate that can draw one-dimensional stable cylindrical wall is a constant diametrically.
Enter boundary condition:
r=r 1place,
t=
t w1
;
r=r 2place,
t=
t w2
; The Temperature Distribution that draws cylindrical wall heat conduction is as follows:
In formula,
rfor the distance between optical fiber Bragg raster and the cylindrical heat conducting wall center of circle;
r 1for the inside radius of hollow cylinder heat conducting wall;
r 2for the external radius of hollow cylinder heat conducting wall;
t w1
for the temperature of cylindrical wall inner radius, it is a fixed value;
t w2
for the temperature of cylindrical wall outside surface,
t(
r) for radius be
rthe temperature at place.
According to conduction model, calculate changing into of optical fiber Bragg raster place temperature:
Fiber Bragg Grating Temperature changes, and due to thermal expansion effects and the optical fiber thermo-optic effect of optical fiber, causes the variation of reflection peak wavelength.
The peak wavelength reflecting meets:
（6）
In formula:
it is the grating cycle;
it is effective refractive index.
(6) formula is carried out to temperature
tdifferentiate can obtain:
In formula:
it is the originally elastic deformation under effect of stress of optical fiber;
it is the elasto-optical effect of optical fiber.
(7) formula both sides, divided by (6) formula, can obtain:
In (8) formula,
for the variation of wavelength;
be the thermo-optical coeffecient of fiber grating, its expression formula is
;
be the thermal expansivity of fiber grating, its expression formula is
;
s t for the temperature-sensitivity coefficient of temperature measuring equipment, thus the wavelength shift of the optical fiber Bragg raster of catalytic combustion type gas concentration meter and temperature be varied to linear relationship.Generally concerning fused quartz optical fiber,
,
.
Formula (1), (5) substitution (8) formula are obtained:
Formula (9) has shown gas percentage composition to be measured
cwith optical fiber Bragg raster wavelength-shift
between mathematical model, by measuring optical fiber Bragg grating wavelength displacement, just can calculate the percentage composition of gas to be measured in gaseous environment.
The beneficial effects of the utility model are:
1, realized the on-line monitoring to combustable gas concentration: the utility model is directly pasted the optical fiber Bragg raster after encapsulation in cylinder heat conducting wall, by the measurement that the concentration change of inflammable gas is converted to the centre wavelength displacement to optical fiber Bragg raster, the concentration of inflammable gas has been carried out to real time on-line monitoring.
2, antijamming capability is strong: adopt electrically insulating material optical fiber Bragg raster, signal transmission is light signal, can resist electromagnetic interference (EMI), meanwhile, reduces in addition the ignite effect of inflammable gas gas to be measured of electric spark, has reduced potential safety hazard.Optical fiber Bragg grating sensor is applicable to exist under the special operation condition in electromagnetic interference (EMI) situation and measures in real time.
3, simple in structure, easy to use.
Accompanying drawing explanation
Fig. 1 is structural representation of the present utility model;
Fig. 2 is the heat conduction distribution plan of cylindrical heat conducting wall in the utility model;
Each label in figure: 1 be optical fiber Bragg raster, 2 for flame proof cover, 3 for catalyst layer, 4 for heating resistor film plating layer, 5 for heating source lead-in wire, 6 for base, 7 for cylindrical heat conducting wall, 8 for electrode, 9 be fiber pigtail.
Embodiment
Embodiment 1: as shown in Figure 1-2, a kind of catalytic combustion type gas concentration meter based on optical fiber Bragg raster, comprises temperature measuring equipment, gas combustion apparatus and explosion isolation device; Described temperature measuring equipment comprises optical fiber Bragg raster 1, cylindrical heat conducting wall 7, fiber pigtail 9, wherein optical fiber Bragg raster 1 is encapsulated into optical fiber temperature-measurement contact by protective casing, optical fiber temperature-measurement contact sticks in cylindrical heat conducting wall 7 endoporus that radii fixus place has held successfully, and fiber pigtail 9 is drawn by the fairlead being positioned on explosion isolation device base 6; Described gas combustion apparatus comprises catalyst layer 3, heating resistor film plating layer 4, heating source lead-in wire 5, electrode 8, wherein catalyst layer 3 applies the outside surface at heating resistor film plating layer 4, heating resistor film plating layer 4 is positioned at cylindrical heat conducting wall 7 outside surfaces, and the heating source of drawing from electrode 8 lead-in wire 5 is connected with external power source; Described explosion isolation device comprises flame proof cover 2, base 6, and wherein flame proof cover 2 is by the temperature measuring equipment and the gas combustion apparatus cover that are embedded on base 6.
Described cylindrical heat conducting wall 7 seals by epoxy resin with the junction of fiber pigtail 9.
Embodiment 2: as shown in Figure 1-2, a kind of catalytic combustion type gas concentration meter based on optical fiber Bragg raster, comprises temperature measuring equipment, gas combustion apparatus and explosion isolation device; Described temperature measuring equipment comprises optical fiber Bragg raster 1, cylindrical heat conducting wall 7, fiber pigtail 9, wherein optical fiber Bragg raster 1 is encapsulated into optical fiber temperature-measurement contact by protective casing, optical fiber temperature-measurement contact sticks in cylindrical heat conducting wall 7 endoporus that radii fixus place has held successfully, and fiber pigtail 9 is drawn by the fairlead being positioned on explosion isolation device base 6; Described gas combustion apparatus comprises catalyst layer 3, heating resistor film plating layer 4, heating source lead-in wire 5, electrode 8, wherein catalyst layer 3 applies the outside surface at heating resistor film plating layer 4, heating resistor film plating layer 4 is positioned at cylindrical heat conducting wall 7 outside surfaces, and the heating source of drawing from electrode 8 lead-in wire 5 is connected with external power source; Described explosion isolation device comprises flame proof cover 2, base 6, and wherein flame proof cover 2 is by the temperature measuring equipment and the gas combustion apparatus cover that are embedded on base 6.
Described cylindrical heat conducting wall 7 seals by epoxy resin with the junction of fiber pigtail 9.
Its concrete implementation step is:
1, optical fiber Bragg raster is put into the hole that cylinder heat conducting wall has been held successfully after sleeve pipe encapsulation, guarantee that optical fiber Bragg raster is positioned at the corresponding fixed position of catalyzer.In cylindrical wall, hollow parts is connected with external environment, and in guaranteeing, the temperature of hollow parts is fixed.
2, by accompanying drawing 1, Fig. 2, make this device, the design parameter in actual fabrication is:
Cylindrical wall is selected porous alumina ceramic, mean coefficient of heat conductivity: 0.85W/ (mK); Choose and be of a size of: cylindrical wall external radius 80 mm, inside radius 10 mm, the distance between optical fiber Bragg raster and the cylindrical heat conducting wall center of circle is 15mm, perforate radius is 1mm.
3, heating resistor film plating layer is selected Pt resistance, and its thickness is 1mm, its
c p heating resistor thermal capacitance is 135 J/ (kgK); Catalyst catalytic performance constant is 1; The radius of flame proof cover is 100mm.
4, inflammable gas is selected, methane, and its parameter is as follows:
Heating power: 890.31KJ/mol; Ignition temperature: 538 (℃).
5, select gas temperature to be measured, the temperature of cylindrical wall inner radius is 20 ℃.
6, catalytic combustion type gas concentration meter is positioned in the gaseous environment to be measured that contains methane, connects stabilized voltage supply, with optical fiber Bragg raster (FBG) demodulator, obtain the Bragg wavelength of optical fiber Bragg raster.
7, when the initial wavelength of optical fiber Bragg raster is 1550 nm,
s t =6.0 × 10
-6℃
-1.By known quantity substitution (9) formula
:
Theory is calculated and is shown, the sensitivity of catalytic combustion type gas concentration meter is 72.18 pm/%.Therefore,, when the wavelength resolution of optical fiber Bragg raster (FBG) demodulator is 1 pm, the resolution of being somebody's turn to do the catalytic combustion type gas concentration meter based on optical fiber Bragg raster is 1.43%.
By reference to the accompanying drawings embodiment of the present utility model is explained in detail above, but the utility model is not limited to above-mentioned embodiment, in the ken possessing those of ordinary skills, can also under the prerequisite that does not depart from the utility model aim, make various variations.
Claims (2)
1. the catalytic combustion type gas concentration meter based on optical fiber Bragg raster, is characterized in that: comprise temperature measuring equipment, gas combustion apparatus and explosion isolation device; Described temperature measuring equipment comprises optical fiber Bragg raster (1), cylindrical heat conducting wall (7), fiber pigtail (9), wherein optical fiber Bragg raster (1) is encapsulated into optical fiber temperature-measurement contact by protective casing, optical fiber temperature-measurement contact sticks in cylindrical heat conducting wall (7) endoporus that radii fixus place has held successfully, and fiber pigtail (9) is drawn by the fairlead being positioned on explosion isolation device base (6); Described gas combustion apparatus comprises catalyst layer (3), heating resistor film plating layer (4), heating source lead-in wire (5), electrode (8), wherein catalyst layer (3) applies the outside surface in heating resistor film plating layer (4), heating resistor film plating layer (4) is positioned at cylindrical heat conducting wall (7) outside surface, and the heating source of drawing from electrode (8) lead-in wire (5) is connected with external power source; Described explosion isolation device comprises flame proof cover (2), base (6), and wherein flame proof cover (2) is by the temperature measuring equipment and the gas combustion apparatus cover that are embedded on base (6).
2. the catalytic combustion type gas concentration meter based on optical fiber Bragg raster according to claim 1, is characterized in that: described cylindrical heat conducting wall (7) seals by epoxy resin with the junction of fiber pigtail (9).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320730183.3U CN203587537U (en) | 2013-11-19 | 2013-11-19 | Catalytic combustion type gas concentration meter based on optical fiber Bragg raster |
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|---|---|---|---|
| CN201320730183.3U CN203587537U (en) | 2013-11-19 | 2013-11-19 | Catalytic combustion type gas concentration meter based on optical fiber Bragg raster |
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|---|---|
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103616408A (en) * | 2013-11-19 | 2014-03-05 | 昆明理工大学 | Catalytic combustion type gas concentration meter based on optical fiber Bragg grating and application method thereof |
| CN106949824A (en) * | 2017-04-17 | 2017-07-14 | 中水东北勘测设计研究有限责任公司 | Underwater sludge blasting cavities radius electrode array test method |
-
2013
- 2013-11-19 CN CN201320730183.3U patent/CN203587537U/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103616408A (en) * | 2013-11-19 | 2014-03-05 | 昆明理工大学 | Catalytic combustion type gas concentration meter based on optical fiber Bragg grating and application method thereof |
| CN106949824A (en) * | 2017-04-17 | 2017-07-14 | 中水东北勘测设计研究有限责任公司 | Underwater sludge blasting cavities radius electrode array test method |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20140507 Effective date of abandoning: 20151014 |
|
| AV01 | Patent right actively abandoned |
Granted publication date: 20140507 Effective date of abandoning: 20151014 |
|
| C25 | Abandonment of patent right or utility model to avoid double patenting |