Background technology
Generally include the ozone automatic analyzer in the monitoring sub-station of auto-monitor of surrounding air quality system, the ozone automatic analyzer utilizes spectroscopy measurement to go out the content of ozone in the atmosphere.Elongated along with service time, light source and the electronic devices and components in the ozone automatic analyzer can wear out, each position component also can change, and this just needs to use O
3Gas is calibrated the ozone automatic analyzer, guarantees the accuracy of measuring.
O
3Because its extremely strong oxidisability can not use steel cylinder to carry out canned and storage usually, so, when being calibrated, the ozone automatic analyzer need use ozone generating apparatus to transform out O at the scene
3Gas.O
3The generation of gas needs as lower device:
1, O
3Generation device, normally used method have point discharge method or ceramic discharge method or ultraviolet light chemistry method etc.Specifically can be referring to patent CN2427509Y, CN2466135Y, CN2670334Y.
Point discharge method or ceramic discharge method are the most frequently used ozone generating method, can produce the ozone concentration of very high (reaching 50%), are mainly used in industrial generation ozone.But these methods are not suitable for producing the O of normal concentration
3, because the O of its generation
3The concentration precision is relatively poor, and can produce minor N O
2, be applied to timing signal and can produce certain interference.
Ultraviolet light chemistry method can produce O high-precision, low concentration
3, be fit to very much be applied to O
3Demarcate.Ultraviolet light chemistry ratio juris is the UV-irradiation O of ultraviolet source emission
2, a small amount of O
2Can absorb the feature ultraviolet light of 185nm wavelength, be converted into O
3, suc as formula (1).
O
2+hv
185nm→O
3 (1)
2, ozone photometer.The ozoniferous concentration accuracy in order to guarantee need feed the ozone that transforms out in the ozone photometer, utilizes spectral technique to record the concentration of ozone.The ozone photometer can be referring to patent CN2921827Y.
Ozone photometer measurement principle is to utilize O
3Absorption to the ultraviolet light of 254nm wavelength obtains O
3Concentration, ultimate principle is the Beer-Lambert relational expression, i.e. formula (2),
I=I
0·e
-αLC (2)
Wherein, I
0Be light source intensity, I is the light intensity of passing behind the tested gas, and L is a light path, and C is the concentration of tested gas, and α is the absorption coefficient of tested gas at specific wavelength.
Environment temperature and pressure can influence the density of sample gas, and the ultraviolet light that ozone is absorbed changes.According to formula (2), consider the influence of temperature, pressure, then (on average) concentration computing formula is,
Wherein, P is the pressure of sample gas, and T is the temperature of sample gas.
In the prior art, above-mentioned ozone generating apparatus and ozone photometer all are splits, have many deficiencies, as:
1, complex structure need provide two gas compartments, is respectively applied for to produce and measure ozone.Need two ultraviolet sources of launching different characteristic wavelength ultraviolet light in ozone generating apparatus and the ozone photometer: the emission wavelength of ozone generating apparatus inner light source must comprise λ=185nm characteristic spectrum, O
2Absorb this wavelength characteristic spectrum and can produce O
3, and the emission wavelength of light source need comprise λ=254nm characteristic spectrum in the ozone photometer, but need to get rid of λ=185nm characteristic spectrum, avoid producing in the measuring process O
3
2, operation inconvenience is in order to obtain light source intensity I in the ozone photometer
0, at first need in photometric gas compartment, feed the air at zero point and (promptly not comprise O
3Air), the light intensity that detector records promptly is light source intensity I
0And, also to repeat aforesaid operations behind the some cycles at interval.
3, measuring accuracy is lower, owing to be not to monitor in the photometer light source intensity in real time to change, therefore, the light source intensity that prestores that utilizes when at every turn measuring might not be a light source intensity real when measuring, and has influenced measuring accuracy.
4, cost is higher, and when adopting ultraviolet irradiation technique, the ozone reforming unit needs two different ultraviolet sources with the ozone photometer, and the price of ultraviolet source is higher, has improved the cost of device.
Summary of the invention
In order to solve above-mentioned deficiency of the prior art, the invention provides the higher gas supply method of a kind of gas concentration indication accuracy, and accurate, simple in structure, the lower-cost gas supply device of a kind of measurement.
For achieving the above object, the present invention adopts following technical scheme:
A kind of gas supply method may further comprise the steps:
The light that a, light source send passes the original gas that includes oxygen in the conversion unit, and wherein, oxygen is converted into ozone under the effect of special wavelength light;
Gas after the conversion feeds in the measuring unit;
The light that b, described light source send is filtered the light of described specific wavelength, passes the gas in the measuring unit, is received by first detector, and converts electric signal to;
Analysis module is handled the electric signal that records, and obtains ozone concentration;
Gas after c, the conversion is discharged from measuring unit, to the known gas of external world's supply ozone concentration.
As preferably, described specific wavelength is λ=185nm.
As preferably, the light that light source sends passes the length that light that the length of gas sends less than light source passes the gas between the filtering apparatus and first detector when arriving the optical filtering module.
As preferably, in step b, first detector records the light intensity at wavelength X=254nm place.
As preferably, in described converting unit and measuring unit, feed at wavelength X=185nm place ozone free the zero gas that transforms, do not have absorption at λ=254nm place, first detector records light that light source at this moment the sends light intensity at wavelength X=254nm place.
As preferably, feeding at λ=254nm place in described measuring unit does not have the zero gas that absorbs, and first detector records light that light source at this moment the sends light intensity at wavelength X=254nm place.
As preferably, second detector is set, be used to monitor the light intensity that light source sends light, the light that light source sends passes the length that light that the length of gas sends less than light source passes the gas between the optical filtering module and first detector when arriving second detector.
As preferably, the light intensity at described second detector monitors wavelength X=254nm place.
In order to realize said method, the invention allows for a kind of like this gas supply device, comprise light source, optical filtering module, conversion unit, measuring unit, be communicated with by gas circuit between conversion unit and measuring unit, on the described conversion unit air intake opening is set, described measuring unit comprises measuring chamber, first detector, exhausr port and analysis module; The shared light source of conversion unit and measuring unit, the light that described light source sends pass conversion unit and produce ozone, after the light that described light source sends passes optical filtering module, measuring unit, arrive described first detector.
Further, described conversion unit and measuring unit are in the both sides of light source.
As preferably, also be provided with second detector that the monitoring light source sends the light intensity of light, its output terminal connects analysis module, and second detector arrives the distance of optical filtering module less than first detector to the distance of light source.
The present invention compared with prior art has following beneficial effect:
1, simple in structure, maintainable good
The present invention can be designed to one with conversion unit and measuring unit, can only need a light source (or a detector): the special wavelength light in the light source emergent light is an ozone with oxygen conversion, and light source emergent light (or after being filtered specific wavelength) is used to measure ozone concentration.
2, measure accurately
The introducing of second detector can be monitored light source intensity in real time, and is used for follow-up Measurement and analysis, has further improved the accuracy of measuring.
Second detector can be monitored light source intensity in real time and change.
The measured signal of second detector can also be transferred to analysis module, and the driving voltage of FEEDBACK CONTROL ultraviolet source is stablized the output intensity of ultraviolet source, thereby improves ozoniferous precision.
3, cost is lower
Can need not to design two independently gas compartments, need not long breather line, only need a light source (or only needing a detector), these have all reduced cost.
Embodiment
Below in conjunction with embodiment, the present invention is done further detailed description.
Embodiment 1:
As shown in Figure 1, a kind of calibrating gas feeding mechanism is used to provide the ozone gas, and described feeding mechanism comprises light source 11, conversion unit 1 and measuring unit 2.
Described conversion unit 1 is provided with air intake opening 12, and inside is provided with light source 11, as adopting mercury lamp, comprises wavelength X=185nm, 254nm in the light of light source 11 emissions.
Described measuring unit 2 connects conversion unit 1, and the gas in the converting unit 1 can freely flow in the measuring unit 2.Measuring unit 2 is provided with exhausr port 25, and inside is provided with optical filtering module 21, gas compartment 22, first detector 23, analysis module 24.Optical filtering module 21 will filter the light of wavelength X=185nm that light source sends, can adopt optical filter.The spacing L of optical filtering module 21 and light source 11
1Less, as 1mm, L
1Much smaller than the distance L between the optical filtering module 21 and first detector 23.
Therefore the present invention only needs a light source, a gas compartment, need not long breather line, thereby whole apparatus structure is become simply, is convenient to safeguard, has also reduced cost simultaneously.
A kind of calibrating gas Supply Method in order to the ozone gas to be provided, as shown in Figure 2, said method comprising the steps of:
A, with zero gas (transform at wavelength X=185nm place ozone free, at the gas of λ=254nm place nothing absorption, as nitrogen) feed as described in conversion unit 1 and the measuring unit 2, the light intensity at wavelength X=254nm place that first detector 23 records is the light intensity I at wavelength X=254nm that light source 11 sends
0, with light intensity I
0 Analysis module 24 is advanced in storage.
The original gas that includes oxygen enters in the conversion unit 1 by air intake opening 12 with the flow of determining;
The light that light source 11 sends passes the original gas in the conversion unit 1, comprises wavelength X=185nm, 254nm in the light that light source sends; Oxygen in the original gas is converted into ozone under the effect of specific wavelength λ=185nm light;
Gas after the conversion enters in the gas compartment 22 in the measuring unit 2;
In conversion process, (light intensity is I to the light of wavelength X=254nm that
light source 11 sends
0) owing to the absorption of ozone in the
conversion unit 1 be attenuated into
C
1Concentration for ozone in the
conversion unit 1; L
1Distance for
light source 11 and
optical filtering module 21;
B, the light that passes behind the conversion unit 1 pass optical filtering module 21, are filtered described specific wavelength λ=185nm, become measuring light;
Measuring light is passed the gas after transforming in the gas compartments 22 in the measuring unit 2, is absorbed by ozone and the back of decaying is received in the light intensity I at wavelength X=254nm place by first detector 23, and is converted to electric signal.Analysis module 24 utilizes the Beer-Lambert relational expression to obtain following computing formula, thereby obtains the concentration C of ozone in the measuring unit 2 interior gases:
In above-mentioned concentration computing formula, the concentration C of ozone in the conversion unit 1
1Close usually with ozone concentration C in the measuring unit 2, and L
1L is in a small amount relatively, therefore can ignore, and ozone concentration C is:
C, the gas that includes ozone are discharged from measuring unit 2 by exhausr port 25, thereby to the known gas of external world's supply ozone concentration value.
Embodiment 2:
As shown in Figure 3, a kind of calibrating gas feeding mechanism, be used to provide the ozone gas, as different from Example 1: second detector 13 also is set in conversion unit 1, be used for monitoring in real time the light intensity at wavelength X=254nm place that light source 11 sends light, second detector 13 arrives the distance of optical filtering module 21 less than first detector 13 to the distance of light source 11.
When feeding zero gas (transform at wavelength X=185nm place ozone free, at the gas of λ=254nm place nothing absorption, as nitrogen) in conversion unit 1, measuring unit 2, the light intensity that first detector 23 records is the light intensity I of wavelength X=254nm that light source 11 sends
0, the light intensity that second detector 13 records is I
1, light intensity I
0With light intensity I
1Between definite relation be: I
0=kI
1Thereby, obtain scale-up factor k, and store in the analysis module 24.
A kind of calibrating gas Supply Method in order to the ozone gas to be provided, said method comprising the steps of:
A, the original gas that includes oxygen enter in the conversion unit 1 by air intake opening 12 with the flow of determining;
The light that light source 11 sends passes the original gas in the conversion unit 1, comprises wavelength X=185nm, 254nm in the light that light source sends; Oxygen in the original gas is converted into ozone under the effect of specific wavelength λ=185nm light;
Gas after the conversion enters in the gas compartment 22 in the measuring unit 2;
In conversion process, the light of wavelength X=254nm that
light source 11 sends owing to the absorption of ozone in the
conversion unit 1 be attenuated into
C
1Concentration for ozone in the
conversion unit 1; L
1For the distance of
light source 11 and
optical filtering module 21, very little usually, as 1mm, L
1Much smaller than the distance L between the
optical filtering module 21 and
first detector 23.
The light of wavelength X=254nm that
light source 11 sends is received by
second detector 13 after passing ozone in the
conversion unit 1, and the light intensity that
second detector 13 receives is
L
2Be the distance of
second detector 13 to light source, very little usually, as 1mm, L
2Much smaller than the distance L between the
optical filtering module 21 and
first detector 23.
Therefore, by the light intensity that second detector 13 removes to monitor in real time wavelength X=254nm that light source 11 sends, saved and fed zero gas (in order to obtain the light intensity I of wavelength X=254nm that light source 11 sends
0) trouble, solved the deficiency that can not monitor light source intensity in real time, improved the accuracy that ozone concentration is measured.
B, the light that passes behind the conversion unit 1 pass optical filtering module 21, are filtered described specific wavelength λ=185nm, become measuring light;
Measuring light is received in the light intensity I at wavelength X=254nm place by first detector 23, and is converted to electric signal after passing gas after transforming in the gas compartments 22 in the measuring unit 2.The relational expression of the light intensity I that the ozone concentration C and first detector receive in the measuring unit 2 as shown in the formula,
Ozone concentration C in the conversion unit 1
1The light intensity I that receives with second detector 13
2Relational expression as shown in the formula,
So, by top two formulas and relational expression I
0=kI
1Can obtain:
In above-mentioned concentration computing formula, the concentration C of ozone in the conversion unit 1
1Close usually with ozone concentration C in the measuring unit 2, and L
1, L
2L is in a small amount relatively, therefore can ignore C
1L
1And C
1L
2, ozone concentration C is:
C, the gas that includes ozone are discharged from measuring unit 2 by exhausr port 25, thereby to the known gas of external world's supply ozone concentration value.
Embodiment 3:
As shown in Figure 4, a kind of calibrating gas feeding mechanism is used to provide the ozone gas, as different from Example 2: exhausr port 14 is set on conversion unit 1, like this, a gas part that produces in the conversion unit 1 is passed in the measuring unit 2, is used for measuring the concentration value that transforms ozone in the gas of back; Another part is then discharged by exhausr port 14, thereby to the known gas of external world's supply ozone concentration value.
A kind of calibrating gas Supply Method, in order to the ozone gas to be provided, as different from Example 2, in step c, the gas after the conversion is discharged from conversion unit 1 by exhausr port 14, thereby to the known gas of external world's supply ozone concentration value.
Embodiment 4:
As shown in Figure 5, a kind of calibrating gas feeding mechanism is used to provide the ozone gas, and described feeding mechanism comprises light source 11, is in the conversion unit 1 and the measuring unit 2 of light source 11 both sides.
Described conversion unit 1 is provided with air intake opening 12, exhausr port 14.
Described measuring unit 2 is provided with air intake opening 26, exhausr port 25, is provided with first detector 23, analysis module 24. described exhausr ports 14 and air intake opening 26 and is communicated with.
Light source 11 adopts mercury lamp, comprises wavelength X=185nm, 254nm in the light of light source 11 emissions.Optical filtering module 21 is attached on the light source 11, filters the light of wavelength X=185nm.
A kind of calibrating gas Supply Method in order to the ozone gas to be provided, said method comprising the steps of:
A, with in the measuring unit 2 as described in zero gas (not having the gas that absorbs at λ=254nm place) feeding as nitrogen, the light intensity at wavelength X=254nm place that first detector 23 records is the light intensity I at wavelength X=254nm that light source 11 sends
0, with light intensity I
0 Analysis module 24 is advanced in storage.
The original gas that includes oxygen enters in the conversion unit 1 by air intake opening 12 with the flow of determining;
The light that light source 11 sends passes the original gas in the conversion unit 1, and the light that light source 11 sends comprises wavelength X=185nm, 254nm; Oxygen in the original gas is converted into ozone under the effect of specific wavelength λ=185nm light;
Gas after the conversion enters in the measuring unit 2 by exhausr port 14, air intake opening 26;
The light that b, light source 11 send passes optical filtering module 21, is filtered described specific wavelength λ=185nm, becomes measuring light;
Measuring light is received by first detector 23 after passing gas in the measuring unit 2, obtains the light intensity I at wavelength X=254nm place, and is converted to electric signal, and analysis module 24 utilizes following computing formula (formula 3 in the background technology) to obtain the concentration value of ozone:
Wherein, I
0Represent measuring light light intensity at wavelength X=254nm place when entering measuring unit 2, in step a, obtain.
Gas after c, the conversion is discharged from conversion unit 1 by exhausr port 14, thereby to the known gas of external world's supply ozone concentration value.
Supplemental instruction about the foregoing description: all adopt the absorption spectroanalysis technology in the foregoing description, can certainly adopt other spectral analysis technique, these technology all are the common practise of this area, do not repeat them here.
Above-mentioned embodiment should not be construed as limiting the scope of the invention.Key of the present invention is that the special wavelength light that utilizes light source to send acts on the oxygen in the original gas, changes into ozone; The light that light source sends passes the gas after the conversion, utilizes spectral technique to obtain the concentration value of ozone in the gas.Under the situation that does not break away from spirit of the present invention, any type of change that the present invention is made all should fall within protection scope of the present invention.