CN100510712C - Infrared gas sensor - Google Patents
Infrared gas sensor Download PDFInfo
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- CN100510712C CN100510712C CN 200710062967 CN200710062967A CN100510712C CN 100510712 C CN100510712 C CN 100510712C CN 200710062967 CN200710062967 CN 200710062967 CN 200710062967 A CN200710062967 A CN 200710062967A CN 100510712 C CN100510712 C CN 100510712C
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Abstract
A gas transducer of infrared type is prepared for using a cavity to contain gas, forming internal wall of said cavity by top plane, bottom plane and arc shaped side wall; coating light reflection material on said internal wall; opening a hole for exchanging air with outside on top plane; arranging a light source and at least one photoelectric element in said cavity; coordinating position and distance of said light source and said photoelectric element to make light from light source be reflected and focused onto said photoelectric element through internal wall of said cavity.
Description
Technical field
The present invention relates to a kind of gas sensor, be specifically related to a kind of infrared gas sensor.
Background technology
Gas detection is in traditional industries such as earthquake prediction, mine safety, petroleum prospecting, atmospheric physics, health care, pollution source monitoring, high-tension apparatus fault diagnosis, Chemical Engineering Process Control, metallurgy, and even all there is application more and more widely in all now new technologies such as fields such as bio-science, microelectronics and new material.
Gas sensor is the core of gas detecting system, is installed in the detecting head usually.In essence, gas sensor is a kind of converter that certain gas volume mark is changed into corresponding electric signal.Gas sensor is classified with gas-sensitive property usually, mainly can be divided into: semi-conductor type gas sensor, galvanochemistry type gas sensor, solid-state electrolyte gas sensor, catalytic combustion type gas sensor, optical type gas sensor, macromolecule gas sensor etc.
Wherein, the infrared gas sensor in the optical type gas sensor is one of focus of research at present, and it possesses following advantage:
(1) energy measurement multiple gases: except monoatomic inert gas and having the diatomic gas of symmetrical junction constitutive element polarity, most of polyatomic molecule gases such as organic and inorganic can be measured with infrared sensor;
(2) measurement range is wide: be limited to 100% on the gas concentration that can measure, and lower limit can be 1,000,000/;
(3) highly sensitive: the subtle change that can measure gas concentration;
(4) precision height, good stability: generally minimumly can reach the 3-5 class precision;
(5) has good selectivity: be specially adapted to measurement, when other concentration of component changes in the combination gas, do not influence the measurement of component to be analyzed to a certain component to be analyzed in the multicomponent gas combination gas;
(6) reliability height, the life-span is long;
(7) can realize analyzing continuously and controlling automatically.
The principle of infrared gas sensor is as follows:
When infrared light passed through gas to be measured, these gas molecules had absorption to the infrared light of specific wavelength, and it absorbs relation and obeys lambert-Bill (Lambert-Beer) absorption law.When light intensity is k, wavelength is that the light beam of λ incides in the air chamber, and the sample in the air chamber has the line of absorption or absorption band at the λ place, and the light intensity of air chamber emergent light then is the k-Δ.
Absorbent properties by medium knows that when light passed through gas to be measured, a part of light was by gas absorption, and a part of light is by gas scattering, and its rule can be described with Beer law: I=Ioe
-α CLWherein Io is for by the preceding light intensity of gas to be measured, and I is the light intensity of light signal after by gas to be measured, and C is the concentration of gas to be measured, and L is the length of the gas to be measured that passes through of light, and α is the absorption coefficient of gas to be measured.For the ease of measuring, following formula is rewritten into:
As can be seen from the above equation, as long as know light, just can try to achieve the concentration of gas to be measured by the ratio of measuring I and Io by the long L of journey of gas to be measured and the absorption coefficient of gas molecule to be measured.
The light wave that light source sends must pass through sufficiently long light path, and gas to be measured could fully absorb light wave, thereby makes measurement result more accurate; Therefore the air chamber in the infrared gas sensor often needs to reach certain-length, and this makes that not only sensor bulk is excessive, and light intensity is difficult for evenly, realizes the also more complicated of gas exchange in the whole air chamber, and therefore the accuracy meeting of measuring is affected.
Summary of the invention
At above deficiency, the invention provides a kind of infrared gas sensor, can realize gasmetry by the less air chamber of enough volumes; Simultaneously, little air chamber can also make gas exchange oversimplify, and improves the accuracy of measuring, and solves the problem of pickup dust-proofing protection against the tide.
The technical solution used in the present invention is:
A kind of infrared gas sensor, comprise a chamber that is used to hold gas, it is characterized in that: the inwall of described chamber is by the plane, top, baseplane and curved wall surround, be coated with reflectorized material on the described inwall, plane, described top has the perforate that is used for extraneous exchanging gas, be placed with a light source and at least one photovalve in the described chamber, described light source matches with the radian of described sidewall and the distance of plane to baseplane, top with the placement location of photovalve, and the light that light source is sent passes through the reflection of described chamber inner wall and converges on the described photovalve;
Described infrared gas sensor also comprises a protective device; Described protective device comprises a housing; Being provided with one deck filtering membrane at least in the described housing, is the boundary line with described filtering membrane, and described housing one side has the perforate that is used for extraneous exchanging gas, and the opposite side sealing is enclosed in described chamber in the described housing.
Further, described light source is visible light-infrared light supply.
Further, the light-sensitive surface of described photovalve is provided with narrow band pass filter, is used to leach the light of respective wavelength to photovalve.
Further, the radian of described sidewall makes sidewall form the part of one first oval ball and the part of at least one second oval ball, first focus of described first and second oval ball coincides with outside the described chamber, second focus lays respectively in the described chamber, described light source is placed at the second focus place at first oval ball, and described photovalve is placed at the second focus place of second oval ball; Described baseplane and top plane parallel, described first focus equates with the distance of plane, described top to the baseplane to the distance on plane, described top.
Further, the projection of focus line on the baseplane of described second oval ball, with the angle of the projection of focus line on the baseplane of described first oval ball be 180 degree.
Further, described at least one photovalve comprises two photovalves, and its light-sensitive surface is provided with narrow band pass filter; Described photovalve is placed on the second focus place of described second oval ball;
The narrow band pass filter that is provided with on the light-sensitive surface of a photovalve leaches the light wave that gas to be measured can absorb and gives this photovalve; The narrow band pass filter that is provided with on the light-sensitive surface of another photovalve leaches the non-absorbent light wave of gas to be measured and gives this photovalve.
Further, the part of described at least one second oval ball comprises the part of two second oval balls; A photovalve is respectively placed at the second focus place of two second oval balls.
Further, two the second oval ball projections of focus line on the baseplane separately equate with the angle of the extended line of the projection of focus line on the baseplane of described first oval ball.
Further, described first oval ball and second oval ball are measure-alike; The subpoint of first focus on the baseplane of described first and second oval ball is in the central point of baseplane.
Further, light sends from light source, and the optical path length that arrives photovalve through the inwall reflection should guarantee that gas to be measured can fully absorb light wave.
Further, described photovalve is rpyroelectric infrared photovalve or infrared thermopile photovalve.
Further, the total area of the perforate on plane, described top is as the criterion be able to satisfy ventilation requirement.
Further, described filtering membrane is a hydrophobic film.
Further, described filtering membrane is a micropore filtering film, and the scope of its micro-pore diameter is 0.2 micron to 3 microns.
Further, also comprise the filtering membrane fixed mount, be used for described filtering membrane is fixed in the described housing.
Further, described filtering membrane fixed mount comprises filtering membrane installing plate and filtering membrane pressing plate;
Described filtering membrane installing plate is fixed in the described housing, its central hollow out, and described filtering membrane is tiled on the described filtering membrane installing plate;
Described filtering membrane pressing plate is an annular slab, has and the corresponding profile of filtering membrane installing plate, is used for the edge of filtering membrane is pressed on described filtering membrane installing plate.
Further, the material of described housing is the ABS engineering plastics.
Further, the perforate of described housing comprises manhole and vertical grizzly bar.
After having adopted technical scheme of the present invention, the volume energy of air chamber obviously dwindles, thereby makes the application of sensor more flexible; In addition, gas exchange is also simple along with dwindling of air chamber volume, makes that gaseous sample and the gas in the external environment in the air chamber is basic identical; Moreover the solution of the present invention has also been eliminated the influence of the inhomogeneous grade of light intensity, has improved the accuracy of gasmetry; And can reach the effect of dust and moisture.
Description of drawings
Fig. 1 is the principle schematic that light path reflects in the infrared gas sensor chamber among the present invention;
Fig. 2 is the structural representation of infrared gas sensor application example one of the present invention;
Fig. 3 is the shell upward view of infrared gas sensor application example one of the present invention;
Fig. 4 is the cut-open view along A-A line among Fig. 3;
Fig. 5 is the air chamber vertical view of infrared gas sensor application example one of the present invention;
Fig. 6 is the cut-open view along A-A line among Fig. 5;
Fig. 7 is the ventilation reflecting plate vertical view of infrared gas sensor application example one of the present invention;
Fig. 8 is the cut-open view along A-A line among Fig. 7;
Fig. 9 is the principle schematic of application example one;
Figure 10 is the structural representation of infrared gas sensor application example two of the present invention;
Figure 11 is the cut-open view along A-A line among Figure 10;
Figure 12 is the front elevation of application example two middle shells;
Figure 13 is the upward view of application example two middle shells;
Figure 14 is the cut-open view along A-A line among Figure 13;
Figure 15 is the front elevation of filtering membrane installing plate in the application example two;
Figure 16 is the left view of filtering membrane installing plate in the application example two;
Figure 17 is the cut-open view along A-A line among Figure 15;
Figure 18 is the front elevation of filtering membrane pressing plate in the application example two;
Figure 19 is the upward view of filtering membrane pressing plate in the application example two.
Embodiment
The present invention is described further below in conjunction with the drawings and specific embodiments.
Hereinafter, gas to be measured is meant the sort of gas that will detect its concentration; Gas is meant the gas in the infrared gas sensor environment of living in, wherein may be mixed with certain density gas to be measured, also may not have gas to be measured; Infrared gas sensor of the present invention can be exported corresponding electric signal according to the difference of gas to be measured concentration in environmental gas.
A kind of infrared gas sensor comprises a chamber that is used to hold gas, and the inwall of described chamber is surrounded by plane, top, baseplane and curved wall; Be coated with reflectorized material on the described inwall, such as can be gold-plated; Plane, described top has the perforate that is used for extraneous exchanging gas; Be placed with a light source and at least one photovalve in the described chamber.Described light source is visible light-infrared light supply, and promptly the spectral range of the light that this light source sent is from the visible light to the infrared light, and just the wavelength coverage of light wave is to 13 μ m from 0.4 μ m.Described photovalve has a light-sensitive surface, is provided with narrow band pass filter above; When irradiate light when this light-sensitive surface, narrow band pass filter leaches the light wave of respective wavelength and gives photovalve, the light wave that is about to that wavelength that gas to be measured can absorb leaches; Photovalve is converted to electric signal output with light intensity.Described light source matches with the radian of described sidewall and the distance of plane to baseplane, top with the placement location of photovalve, and the light that light source is sent passes through the reflection of described chamber inner wall and converges on the described photovalve.The position of perforate is not concrete on the plane, top limits, and the summation of perforated area only needs to guarantee ventilation requirement, promptly should make the area of remainder on the plane, top big as far as possible, is exactly to make the area on the surface that can be used in reflection in the plane, top big as far as possible in fact.
The radian of described sidewall makes sidewall form the part of one first oval ball and the part of at least one second oval ball, is convenient narration, and the part that forms the part of first, second oval ball on the sidewall is called first, second ellipsoidal surface; The first focus P of described first and second oval ball coincides with outside the described chamber, and second focus lays respectively in the described chamber; Described baseplane and top plane parallel, the described first focus P equates with the distance of plane, described top to the baseplane to the distance on plane, described top.
As shown in Figure 1, place described light source at the second focus place of first oval ball, described photovalve is placed at the second focus place of second oval ball; The point subpoint of P on the baseplane is P ', and by above as can be known, some P and some P ' equate to the distance on plane, described chamber top, and 2 line L is perpendicular to plane, described top, and therefore putting P ' can be regarded as the mirror point of a P with respect to plane, described top.The light that light source sent is dispersed after entering chamber, because the characteristics of ellipsoidal surface are can accurately converge the light that sends of a focus to another focus, therefore that part of light that shines first ellipsoidal surface all can converge to a P through after the reflection of this ellipsoidal surface, is reflected into first reflection specifically.But owing to push up stopping of plane, this part light can be reflected when shining the plane, top, is reflected into reflection for the second time specifically; According to the reflection of light principle as can be known, the light path of this part light behind the plane reflection of top, light path when not pushing up the plane is the mirror image symmetry with respect to the plane, top, so this part light all can converge to the mirror point of a P for the plate inside surface after reflecting for the second time, promptly puts on the P '.These light reflex to again on the plane, top through some P ', are reflected into reflection for the third time specifically; By the reflection of light principle as can be known, this part light is light reflected for the third time, with light path after the reflection for the second time be axisymmetric for line L, but the direct of travel of light is opposite; Therefore this part light arrives the process on plane, top through some P ' reflection back, the light path that can regard as after this part light reflects along the second time from P ' point is returned the process of pushing up the plane, by the light path principle of reversibility as can be known, after this part light arrives plane, top and be reflected (this time being reflected into the 4th secondary reflection), the reverse extending line of its light path must all pass through some P, these light can be regarded as by a light that the P place sends, therefore when shining second ellipsoidal surface, they must converge on this ellipsoidal surface second focus, promptly on the photovalve.
By above as can be known, when second ellipsoidal surface and first ellipsoidal surface have same size, or it is bigger than first ellipsoidal surface, and the projection of focus line on the baseplane of second oval ball, with the angle of the projection of focus line on the baseplane of described first oval ball be 180 when spending, can have maximum light to converge on the photovalve.When first oval ball and second oval ball had same size, the subpoint P ' of the first focus P on the baseplane should be in the central point of baseplane.
When light was propagated in chamber, gas to be measured can absorb the light wave of specific wavelength, and the light intensity of the light wave by testing this wavelength just can be extrapolated the concentration of gas to be measured.The light that light source sends, shining the light that also reflects through plane, top, baseplane and second ellipsoidal surface on first ellipsoidal surface can converge on the photovalve, and shine the light of other parts, have only minority can arrive photovalve, so the light wave that photovalve measures mainly come from that part of light that reflects through first ellipsoidal surface, plane, top, baseplane and second ellipsoidal surface.Before this part light is shining photovalve, all through five secondary reflections, the optical path length of light wave process is following optical path length sum: the light path of light from light source to first ellipsoidal surface, the light path from first ellipsoidal surface to the plane, top, light path and the light path from second ellipsoidal surface to photovalve to the light path on plane, top, plane, top to second ellipsoidal surface again from the plane, top to the light path of baseplane, from the baseplane.Part light can guarantee that from the optical path length that light source arrives photovalve gas to be measured fully absorbs light wave and gets final product.Therefore the length that can the less air chamber of enough volumes guarantees light path, and the less air chamber of volume and external environment are also fairly simple when carrying out gas exchange.
For eliminating the influence that factors such as light intensity is inhomogeneous cause measurement result, two photovalves can be set, its light-sensitive surface is provided with narrow band pass filter, and this optical filter is used to leach the light wave of specific wavelength; Described photovalve is placed on the second focus place of described second oval ball; Photovalve is used to measure can be by the intensity of the light wave of that wavelength of gas absorption to be measured, and output measuring-signal, the narrow band pass filter that is provided with on its light-sensitive surface leach the light wave of that wavelength that gas to be measured can absorb and give this photovalve; Another photovalve is used to measure the intensity of the non-absorbent light wave of gas to be measured, the output reference signal, and the narrow band pass filter that is provided with on its light-sensitive surface leaches the non-absorbent light wave of gas to be measured and gives this photovalve.Reference signal can play the effect of correction to measuring-signal, thereby makes measurement result more accurate.
When using two photovalves, can all be placed on them the focus place of second oval ball; Another kind of implementation is that the part of described at least one second oval ball comprises the part of two second oval balls; A photovalve is respectively placed at the second focus place of two second oval balls.At this moment, in order to make, two the second oval ball projections of focus line on the baseplane separately equate with the angle of the extended line of the projection of focus line on the baseplane of described first oval ball.The light that sends from light source is converged to respectively after two the second oval balls reflections respectively on the photovalve of focus separately, thereby has realized the single light source twin-beam.
Described photovalve can adopt rpyroelectric infrared photovalve or infrared thermopile photovalve, in actual applications, also can adopt corresponding photovalve as required.
For dust and moisture, this infrared gas sensor can also comprise a protective device, and described protective device comprises a housing; Being provided with one deck filtering membrane at least in the described housing, is the boundary line with described filtering membrane, and described housing one side has the perforate that is used for extraneous exchanging gas, and the perforate of described housing comprises manhole and vertical grizzly bar; The opposite side of housing has the interface that is used to dock described sensor cavities perforate.
Another implementation that has the infrared gas sensor of protective device is: described protective device comprises a housing; Being provided with one deck filtering membrane at least in the described housing, is the boundary line with described filtering membrane, and described housing one side has the perforate that is used for extraneous exchanging gas, and the perforate of described housing comprises manhole and vertical grizzly bar; The opposite side sealing of described housing is enclosed in described chamber in the housing.
Described protective device also comprises the filtering membrane fixed mount, and this fixed mount comprises filtering membrane installing plate and filtering membrane pressing plate, and described filtering membrane installing plate and filtering membrane pressing plate match filtering membrane is fixed in the described housing; Described filtering membrane installing plate is fixed in the described housing, its central hollow out, and described filtering membrane is tiled on the described filtering membrane installing plate; Described filtering membrane pressing plate is an annular slab, has and the corresponding profile of filtering membrane installing plate, is used for the edge of filtering membrane is pressed on described filtering membrane installing plate.
Described filtering membrane is the hydrophobic micropore filtering membrane, and the scope of its micro-pore diameter is 0.2 micron to 3 microns.The material of described housing is the ABS engineering plastics, also can adopt other material in the practical application.
With an application example the present invention is carried out more detailed elaboration below.
The infrared methane sensor that application example one is used for the colliery can be used for detecting the methane concentration in colliery; Gases methane to be measured has an extremely strong absorption peak to the infrared light of 3.33 mum wavelengths, and water vapor in the common foreign gas in colliery and carbon dioxide there is no obvious absorption to the light wave of this wavelength; Utilize this spectral characteristic to realize the detection of methane.
As shown in Figure 2, infrared methane sensor comprises air chamber shell 1, air chamber 2, ventilation reflecting plate 3, two photovalves, narrow band pass filter, light source and printed boards 4.
Described light source is visible light-infrared light supply.
In this example, photovalve adopts the rpyroelectric infrared photovalve, the spectral range of its energy measurement at least from 3.33 μ m to 3.9 μ m; Wherein, an infrared electro element is as survey sensor, and the narrow band pass filter that is provided with on its light-sensitive surface leaches the light wave that wavelength is 3.33 μ m, and this part light wave can be by methane adsorption, and the electric signal of this infrared sensor output is a measuring-signal; Another infrared electro element is as the reference sensor, and the narrow band pass filter that is provided with on its light-sensitive surface leaches the light wave that wavelength is 3.9 μ m, and the light wave of this part can be by methane adsorption, and the electric signal of this infrared electro element output is a reference signal.Can obtain the concentration of methane in the environmental gas by comparing and measuring signal and reference signal.
Described light source and infrared electro element all are installed in the printed board 4, link to each other with power supply by this printed board 4, and photovalve is also by these printed board 4 output signals.
Shown in Fig. 3,4, described air chamber shell 1 is a stainless steel cylinder, and external diameter is 20mm, and internal diameter is 17.6mm, high 19mm; The thick 0.5mm of its end face has the perforate that diameter is 14.2mm, bottom surface opened; For making air chamber 2 interior gases clean, do not allow dust pollution light path and optical system, top installing screen pack in described air chamber shell 1, should with in the example be with double-layer stainless steel net 5 as screen pack, this stainless (steel) wire 5 is circular, diameter 17.5mm, the thickness of individual layer is 0.4mm, it is placed in the air chamber shell 1, and one side is close to described perforate, another side and described ventilation reflecting plate 3 next-door neighbours; Described air chamber 2 end faces are close to below the ventilation reflecting plate 3; Described printed board 4 is fixed on the bottom surface of air chamber 2 by the bottom of epoxy packages at air chamber shell 1.
Shown in Fig. 5,6, the profile of described air chamber 2 is cylindrical, and external diameter is 17.5mm, high 12.8mm, and the direction of its end face in air chamber has the chamber 6 that is used to hold gas; Described ventilation reflecting plate 3 covers on the end face of air chamber 2, and its lower surface is the circle of diameter 16mm as the plane, top of chamber 6.
Shown in Fig. 7,8, described ventilation reflecting plate 8 is a cylindrical structural, diameter 17.5mm, and thick 0.4mm, its center has the big air hole that a diameter is 2.8mm; In addition, also have the little air hole that 12 diameters are 1.8mm on this ventilation reflecting plate 8, the center of circle of these little air holes is being the center of circle with this plate center of circle, and radius is evenly to distribute on the circumference of 6.2mm.The lower surface of this ventilation reflecting plate is as the plane, top of described chamber 6, and the part on this surface except that air hole is a reflecting surface; In actual applications, this ventilation reflection also can be adopted other design proposal, and its principle of design is can realize under the prerequisite of ventilating, assurance reflecting surface maximum, and promptly the area of perforate can satisfy ventilation requirement just and gets final product on the plate.
As shown in Figure 9, the inwall of described chamber 6 is surrounded by plane, top, baseplane and curved wall.The radian of described sidewall makes sidewall form the part of one first oval ball and the part of two second oval balls, is convenient narration, and the part that forms the part of first, second oval ball on the sidewall is called first, second ellipsoidal surface; First focus of described first and second oval ball coincides with outside the described chamber, and second focus lays respectively in the described chamber; Described baseplane and top plane parallel, described first focus equates with the distance of plane, described top to the baseplane to the distance on plane, described top, is 9.4mm.Light source is placed at the second focus place of first oval ball, and a photovalve is respectively placed at the second focus place of two second oval balls.
As shown in Figure 6, the bottom of air chamber 2 offers three cylindrical channels 7,8,9 that communicate, vertical with air chamber 2 bottom surfaces with described chamber 6, the described printed board that light source and photovalve are installed is fixed on air chamber 2 tops, described light source enters in the described chamber 6 by passage 7, and two photovalves enter in the described cavity 6 by passage 8 and 9 respectively.As shown in Figure 5, the diameter of passage 7 is 3.3mm, and passage 8 and 9 diameter are 5.05mm, and passage 7 and 9 distance of center circle are from being 9.6mm, and the distance of passage 8 centers of circle and passage 7,9 circle center line connectings is 4.8mm.
Gas is entered in the chamber 6 by the air hole on the ventilation reflecting plate 3 through after the filtration of stainless (steel) wire 5 in the external environment; The light of described light emitted is converging to after chamber 6 internal reflections on the light-sensitive surface of the infrared electro element that is provided with narrow band pass filter; Photovalve is converted to electric signal output with light intensity signal.
Application example two is improvement projects of application example one, for having the infrared methane sensor of protective device; Shown in Figure 10,11, in this sensor, all structures in the air chamber shell 1 are with application example one, this air chamber shell 1 is fixed in the shell 30, the only end sealing of this shell 30, air chamber shell 1 has the end of an end of screen pack towards these shell 30 openings, and shell 30 has external thread at this end.
This sensor also comprises a protective device 20 in addition, and this protective device 20 comprises: housing 201, one deck filtering membrane, filtering membrane installing plate 202 and filtering membrane pressing plate 203 at least.
To shown in Figure 14, described housing 201 is formed from can roughly regarding as in shape by four parts as Figure 12, and its bottom is a round platform, and remainder is three cylinders that diameter strengthens successively, and whole housing height is 31.5mm.
Described frustum cone height is 10mm; The center of this round platform bottom surface offers the manhole that diameter is 1.99mm, the manhole that also to offer 6 diameters in addition be 1.99mm, and it is the center of circle that the center of circle of these 6 manholes is evenly distributed on the bottom center, radius is on the circumference of 3.66mm; The side of round platform offers vertical grizzly bar, and the width of each grizzly bar is 3mm, and the angle between the center line of adjacent grill is 30 degree, and these grizzly bars extend on the side of first adjacent cylinder always, and the diameter of this cylinder is 31mm.Perforate on round platform and first column part is used to realize housing 201 inner spaces and extraneous gas exchange, and the perforate of saying here comprises the manhole on housing 201 bottom surfaces and the gap of each grizzly bar.It is under the situation about determining at sectional area that described perforate is distributed on the bottom surface of round platform and the side, has bigger breathing area.In the practical application, the perforate on the housing also can have other design.
Filtering membrane is fixed in the ensuing column part; Described filtering membrane is hydrophobic miillpore filter, and the scope of micro-pore diameter is 0.2 micron to 3 microns.Micro-pore diameter is littler than minimum water droplet and dust granules, than the big hundred times of gas molecule, therefore can reach the function of waterproof and dustproof, does not influence ventilative simultaneously.In the present embodiment, this filtering membrane thickness is 20 to 30 microns.
Described filtering membrane installing plate 202 and filtering membrane pressing plate 203 cooperate, and described filtering membrane is fixed on the housing 201; With this filtering membrane is the boundary line, and described housing 201 1 sides are provided with extraneous carries out the perforate of gas exchange, in the present embodiment, and the perforate on the promptly above said round platform of this perforate and first cylinder; Opposite side has the interface that is used to dock described chamber top plane perforate, and in this enforcement, this interface refers to the internal thread in last cylinder.Can only realize gas exchange by this filtering membrane between the both sides of housing 201, be after ambient atmos enters protective device 20, earlier through this membrane filtration, just can enter the space at perforate place, plane, described chamber top then, so just avoid wet gas and dust to enter chamber and photovalve has been impacted, and do not influenced chamber and extraneous gas exchange.
Certainly, also described shell 30 can be regarded as the part of protective device 20, in this case, be boundary with the filtering membrane in the housing of protective device 20 201, and a side is provided with perforate, and the opposite side sealing is enclosed in described chamber in the housing 201.
To shown in Figure 17, described filtering membrane installing plate 202 is a plectane as Figure 15, and the middle body hollow out is mesh shape, and this is in order to give filtering membrane to support, in case filtering membrane is sagging because of action of gravity in ventilation; Form the taeniae and all wide 1mm of horizontal stripe of grid, the pore size of network is 2mm * 2mm; The periphery of filtering membrane installing plate 202 is provided with two draw-in grooves and two clamps; Relevant positions in the described housing 201 are provided with draw-in groove, and two clamps of filtering membrane installing plate 202 cooperate with the draw-in groove on the described housing, and this installing plate 202 is fixed in the housing 201; Latticed part on the filtering membrane installing plate 202 is than hanging down 0.5mm on every side; Filtering membrane is tiled on this filtering membrane installing plate 202.
Shown in Figure 18,19, described filtering membrane pressing plate 203 is the annular plate, and its periphery is provided with two clamps, is used for cooperating with draw-in groove on the filtering membrane installing plate 202, and this pressing plate 203 is fixed on this installing plate 202; One axially outstanding annulus is arranged on a side surface of pressing plate 203, highly is 0.5mm, and after this pressing plate 203 was fixed on the filtering membrane installing plate 202, this outstanding annulus was pressed on the edge of filtering membrane on the grid part of this installing plate 202.
Last column part is positioned at the top of housing 201, its inside surface has screw thread, be used for being threaded with shell 30 impermeability, the plane---the perforate and the external world on the reflecting plate of promptly ventilating can't directly carry out gas exchange to make the chamber top, that is to say, in the perforate and two spaces that should be in filtering membrane respectively and be separated out of the perforate on the housing 201 of ventilation on the reflecting plate.For increasing friction force, the strip projection is arranged on the outside surface of this part with firmly convenient.
In the present embodiment, the material of described housing 201 adopts the ABS engineering plastics, the ABS engineering plastics are PC+ABS (engineering plastic alloy), at the Chinese name of chemical industry plastic alloy, called after PC+ABS why, be because this material had both had good heat-resisting weatherability, dimensional stability and the impact resistance of PC resin, have the good processing fluidity of ABS resin again.Adopt the ABS engineering plastics can alleviate the weight of protective device, and can be anticorrosion, explosion-proof.In actual applications, also can select the anticorrosion and explosion-proof material of other energy.
Certainly; the present invention also can have other various embodiments; under the situation that does not deviate from spirit of the present invention and essence thereof; those of ordinary skill in the art work as can make various corresponding changes and distortion according to the present invention, but these corresponding changes and distortion all should belong to the protection domain of the appended claim of the present invention.
Claims (18)
1, a kind of infrared gas sensor, comprise a chamber that is used to hold gas, it is characterized in that: the inwall of described chamber is by the plane, top, baseplane and curved wall surround, be coated with reflectorized material on the described inwall, plane, described top has the perforate that is used for extraneous exchanging gas, be placed with a light source and at least one photovalve in the described chamber, described light source matches with the radian of described sidewall and the distance of plane to baseplane, top with the placement location of photovalve, and the light that light source is sent passes through the reflection of described chamber inner wall and converges on the described photovalve;
Described infrared gas sensor also comprises a protective device; Described protective device comprises a housing; Being provided with one deck filtering membrane at least in the described housing, is the boundary line with described filtering membrane, and described housing one side has the perforate that is used for extraneous exchanging gas, and the opposite side sealing is enclosed in described chamber in the described housing.
2, infrared gas sensor as claimed in claim 1 is characterized in that: described light source is visible light-infrared light supply.
3, infrared gas sensor as claimed in claim 1 is characterized in that: the light-sensitive surface of described photovalve is provided with narrow band pass filter, is used to leach the light of respective wavelength to photovalve.
4, infrared gas sensor as claimed in claim 1, it is characterized in that: the radian of described sidewall makes sidewall form the part of one first oval ball and the part of at least one second oval ball, first focus of described first and second oval ball coincides with outside the described chamber, second focus lays respectively in the described chamber, described light source is placed at the second focus place at first oval ball, and described photovalve is placed at the second focus place of second oval ball; Described baseplane and top plane parallel, described first focus equates with the distance of plane, described top to the baseplane to the distance on plane, described top.
5, infrared gas sensor as claimed in claim 4 is characterized in that: the projection of focus line on the baseplane of described second oval ball, with the angle of the projection of focus line on the baseplane of described first oval ball be 180 degree.
6, infrared gas sensor as claimed in claim 4 is characterized in that: described at least one photovalve comprises two photovalves, and its light-sensitive surface is provided with narrow band pass filter; Described photovalve is placed on the second focus place of described second oval ball;
The narrow band pass filter that is provided with on the light-sensitive surface of a photovalve leaches the light wave that gas to be measured can absorb and gives this photovalve; The narrow band pass filter that is provided with on the light-sensitive surface of another photovalve leaches the non-absorbent light wave of gas to be measured and gives this photovalve.
7, infrared gas sensor as claimed in claim 6 is characterized in that: the part of described at least one second oval ball comprises the part of two second oval balls; A photovalve is respectively placed at the second focus place of two second oval balls.
8, infrared gas sensor as claimed in claim 7 is characterized in that: two the second oval ball projections of focus line on the baseplane separately equate with the angle of the extended line of the projection of focus line on the baseplane of described first oval ball.
9, infrared gas sensor as claimed in claim 4 is characterized in that: described first oval ball and second oval ball are measure-alike; The subpoint of first focus on the baseplane of described first and second oval ball is in the central point of baseplane.
10, infrared gas sensor as claimed in claim 1, it is characterized in that: light sends from light source, and the optical path length that arrives photovalve through the inwall reflection should guarantee that gas to be measured can fully absorb light wave.
11, infrared gas sensor as claimed in claim 1 is characterized in that: described photovalve is rpyroelectric infrared photovalve or infrared thermopile photovalve.
12, infrared gas sensor as claimed in claim 1 is characterized in that: the total area of the perforate on plane, described top is as the criterion be able to satisfy ventilation requirement.
13, as each described infrared gas sensor of claim 1 to 12, it is characterized in that: described filtering membrane is a hydrophobic film.
14, as each described infrared gas sensor of claim 1 to 12, it is characterized in that: described filtering membrane is a micropore filtering film, and the scope of its micro-pore diameter is 0.2 micron to 3 microns.
15, as each described infrared gas sensor of claim 1 to 12, it is characterized in that: also comprise the filtering membrane fixed mount, be used for described filtering membrane is fixed in the described housing.
16, infrared gas sensor as claimed in claim 15 is characterized in that: described filtering membrane fixed mount comprises filtering membrane installing plate and filtering membrane pressing plate;
Described filtering membrane installing plate is fixed in the described housing, its central hollow out, and described filtering membrane is tiled on the described filtering membrane installing plate;
Described filtering membrane pressing plate is an annular slab, has and the corresponding profile of filtering membrane installing plate, is used for the edge of filtering membrane is pressed on described filtering membrane installing plate.
17, infrared gas sensor as claimed in claim 16 is characterized in that: the material of described housing is the ABS engineering plastics.
18, as each described infrared gas sensor of claim 1 to 12, it is characterized in that: the perforate of described housing comprises manhole and vertical grizzly bar.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200710062967 CN100510712C (en) | 2007-01-23 | 2007-01-23 | Infrared gas sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200710062967 CN100510712C (en) | 2007-01-23 | 2007-01-23 | Infrared gas sensor |
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| Publication Number | Publication Date |
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| CN101004380A CN101004380A (en) | 2007-07-25 |
| CN100510712C true CN100510712C (en) | 2009-07-08 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN 200710062967 Expired - Fee Related CN100510712C (en) | 2007-01-23 | 2007-01-23 | Infrared gas sensor |
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| CN (1) | CN100510712C (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101105449B (en) * | 2007-08-08 | 2010-09-15 | 天地科技股份有限公司 | Double light source double sensitive element infra-red multiple gas detection sensor |
| CN101567120B (en) * | 2009-04-27 | 2011-04-20 | 中北大学 | Portable infrared gas alarm apparatus |
| US8322191B2 (en) * | 2010-06-30 | 2012-12-04 | Honeywell International Inc. | Enhanced cavity for a photoacoustic gas sensor |
| CN102313702B (en) * | 2010-07-03 | 2013-07-10 | 聚光科技(杭州)股份有限公司 | Photoelectric analysis method and device for gas in pipeline |
| US9907505B2 (en) * | 2011-04-08 | 2018-03-06 | Sentire Medical Systems, Llc | Methods and devices for detecting bowel perforation |
| CN102495003B (en) * | 2011-11-16 | 2013-12-04 | 上海芯敏微系统技术有限公司 | Small long light path infrared gas sensor module |
| CN104198426A (en) * | 2014-09-22 | 2014-12-10 | 合肥工业大学 | Diffuse reflection light gas absorption calculation model for non-dispersive infrared sensor system |
| CN104359850B (en) * | 2014-11-19 | 2018-01-09 | 太原理工大学 | A kind of infrared gas sensor based on three spheroid absorption chamber structures |
| CN105717064A (en) * | 2016-02-04 | 2016-06-29 | 杭州巨之灵科技有限公司 | Expiration alcohol tester and alcohol testing method |
| CN109470644B (en) * | 2018-12-29 | 2024-05-03 | 汉威科技集团股份有限公司 | Compact infrared optical gas absorption cell and infrared gas sensor |
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2007
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| CN101004380A (en) | 2007-07-25 |
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