CN203259462U - Apparatus for measuring equivalent water content in N2O4 through sepectrometry - Google Patents

Abstract

The utility model relates to the measure technology field, and especially relates to a technology for measuring the equivalent water content in N2O4 through sepectrometry, and an apparatus thereof. The apparatus for measuring the equivalent water content in N2O4 through sepectrometry is composed of a water infrared analyzer, a diplopore system 3 and an integrating sphere 5, the diplopore system 3 is placed in a parallel optical path between the slit emitted by a monochromator and a sample chamber, the integrating sphere 5 is placed in the parallel optical path behind the sample chamber, incident light is perpendicular to the injection window of the integrating sphere, and the photosensitive surface of a near infrared photoelectric detector 6 overlaps with the inner surface of the integrating sphere and is not directly irradiated by the incident light. The apparatus and the measure method have the advantages of accuracy, reliability, and simple operation, and are suitable for the accurate test of the equivalent water content in N2O4 and the determination of the standard substance of the equivalent water content in N2O4.

Description

Spectroscopic methodology N 2O 4Middle corresponding water content measurement mechanism

One, technical field

The utility model belongs to field of measuring technique, relates to N ₂O ₄Middle corresponding water content measuring technique, particularly N ₂O ₄Middle corresponding water content measurement mechanism.

Two, background technology

N ₂O ₄Middle corresponding water content generally adopts vapor-phase chromatography and near infrared spectroscopy to measure, before measuring, vapor-phase chromatography needs the standard solution drawing standard curve according to series concentration, therefore operate comparatively loaded down with trivial detailsly, more employing near infrared spectroscopies, namely adopt bright pink outer analysis instrument to measure N ₂O ₄Middle corresponding water content.

Bright pink outer analysis instrument is according to N ₂O ₄In the suitable feature absorbance indicating value of water, contrast N ₂O ₄The corresponding relation of middle corresponding water content standard substance and feature absorbance is determined the value of sample, but due to non-linear, the unevenness of monochromatic light light beam of instrument photodetector response and the unevenness of detector photosurface, cause when absorbance indicating value generation of the transmission deviation of bright pink outer analysis instrument, and then cause N ₂O ₄Middle corresponding water content indicating value produces deviation.

Three, summary of the invention

The purpose of this utility model is to provide a kind of spectroscopic methodology N ₂O ₄Middle corresponding water content measurement mechanism guarantees N ₂O ₄The accuracy of measurement of middle corresponding water content solves N simultaneously ₂O ₄The accuracy problem of middle corresponding water content standard substance definite value.

The utility model is achieved in that the superposition principle based on light, and measurement mechanism adopts the diplopore system to carry out gamma correction to the transmittance indicating value, improves the accuracy of transmittance indicating value; Adopt integrating sphere to be pooled to the photosurface of detector, the impact of the unevenness of the unevenness of reduction monochromatic light light beam and the photosurface of detector on the transmittance indicating value after will the light Multi reflection through sample.

The spectroscopic methodology N that the utility model relates to ₂O ₄Middle corresponding water content measurement mechanism, it is characterized in that: formed by bright pink outer analysis instrument, spectacle plate 3 and integrating sphere 5, spectacle plate 3 is comprised of A, B hole, the Area Ratio N in B hole and A hole is between 1.5～5, spectacle plate 3 is placed in the parallel light path between monochromator exit slit and sample chamber, integrating sphere 5 is placed in the parallel light path behind the sample chamber, incident light is perpendicular to the integrating sphere incidence window, the photosurface of near infrared photodetector 6 overlaps with the integrating sphere inside surface, and incident light is the photosurface of direct irradiation detector 6 not.

The spectroscopic methodology N that the utility model relates to ₂O ₄Middle corresponding water content measurement mechanism is characterized in that: be comprised of bright pink outer analysis instrument, spectacle plate 3 and integrating sphere 5, bright pink outer analysis instrument adopts the twin-beam light path; Spectacle plate 3 is comprised of A, B hole, the Area Ratio N in B hole and A hole is between 1.5～5, spectacle plate 3 is placed in the parallel light path between monochromator exit slit and sample chamber, integrating sphere 5 is placed in the parallel light path behind the sample chamber, incident light is perpendicular to the integrating sphere incidence window, the photosurface of near infrared photodetector 6 overlaps with the integrating sphere inside surface, and incident light is the photosurface of direct irradiation detector 6 not.

The spectroscopic methodology N that the utility model relates to ₂O ₄Middle corresponding water content measurement mechanism is characterized in that: described integrating sphere 5 is spherical structure, and window area is not more than 5% of integrating sphere inner surface area.

The spectroscopic methodology N that the utility model relates to ₂O ₄Middle corresponding water content measurement mechanism is characterized in that: the reflectivity of described integrating sphere inside surface is not less than 80%.

The spectroscopic methodology N that the utility model relates to ₂O ₄Middle corresponding water content measurement mechanism is characterized in that: in described spectacle plate, the Area Ratio N in B hole and A hole is between 2～3.

The spectroscopic methodology N that the utility model relates to ₂O ₄The corresponding water content measurement mechanism, reliable and stable, simple to operate, definite value is accurate, is applicable to N ₂O ₄Middle corresponding water content is accurately measured and N ₂O ₄Middle corresponding water content standard substance definite value.

Four, description of drawings

The spectroscopic methodology N that accompanying drawing 1 the utility model relates to ₂O ₄Middle corresponding water content measurement mechanism single beam structural representation

The spectroscopic methodology N that accompanying drawing 2 the utility model relate to ₂O ₄Middle corresponding water content measurement mechanism twin-beam structural representation

The spectacle plate structural representation that accompanying drawing 3 the utility model relate to

Wherein: 1-light source; 2-monochromator; 3-spectacle plate; 4-sample chamber; 5-integrating sphere; 6-near infrared photodetector; 7-chopper; 8-plane mirror; 9-plane mirror; 10-chopper.

Five, embodiment

Below in conjunction with accompanying drawing, the utility model content is described in further detail, but not as the restriction to the utility model content.

Embodiment one

Take a kind of single beam measurement mechanism as example, its structure is replaced by the detector of the bright pink outer analysis instrument of Spectra-760G the integrating sphere form, adds spectacle plate and form as shown in Figure 1.

The structure of spectacle plate 3 as shown in Figure 3, the A hole is of a size of 2mm * 8mm, the B hole is of a size of 4mm * 8mm, when being placed in respectively the parallel light path after monochromator, makes incident light can be covered with A hole, B hole.

Integrating sphere 5 diameter 60mm, window diameter 18mm, coating barium sulphate (reflectivity 80%), the photosurface of InCaAs detector 6 overlaps with the inwall of integrating sphere 5, its normal is vertical with incident light, and incident light obtains perpendicular to the integrating sphere incidence window single beam N that the utility model relates to ₂O ₄Middle corresponding water content measurement mechanism, the corresponding water content of measurement testing sample after gamma correction, Criterion curve.

(a) gamma correction: by the running program rotating shutter, make the complex light dispersion of light source for measuring the near infrared monochromatic light that needs, regulate the supply current of light-source system 1, make through the Initial Voltage Value=1700mv after the monochromatic light in B hole, the A hole is placed in light path, measures the signal value U that sees through behind the A hole _A0, calculating mean value

By formula (1) radiation flux of calculate seeing through B hole and A hole compares N.

$N=\frac{U_{B0}}{{\stackrel{\‾}{U}}_{A0}}---\left(1\right)$

Reduce successively light intensity, make the magnitude of voltage that sees through behind the B hole be followed successively by 0.8,0.6,0.4,0.2 of initial value, be 1360mv, 1020mv, 680mv, 340mv, by formula (2) calculate transmittance indicating value τ, by formula (3) calculate the non-linear deviation delta τ of transmittance indicating value, and result of calculation is as shown in table 1.

$\mathrm{\&tau;}=\frac{N\&CenterDot;{\stackrel{\&OverBar;}{U}}_{\mathrm{<figure-callout\; id="0"\; label="A\; U\; B"\; filenames="HDA00003258768900013.png"\; state="\{\{state\}\}">A</figure-callout>}}}{U_B}\&times;100\%---\left(2\right)$

$\mathrm{\&Delta;\&tau;}=(\frac{N\&CenterDot;{\stackrel{\&OverBar;}{U}}_A}{U_{B0}}-\frac{{\stackrel{\&OverBar;}{U}}_B}{U_{B0}})\&times;100\%---\left(3\right)$

Table 1 diplopore method corrected value

According to the measurement data of transmittance indicating value τ and non-linear deviation delta τ in table 1, Δ τ _sWith the relation curve (4) of τ be,

Δτ _s=0.009τ ²-0.0095τ+0.0005 （4）

Calculate the non-linear deviation delta τ of transmittance indicating value τ according to formula (4) _s, by formula (5) calculate the transmission ratio τ after gamma correction _s, and calculate τ _sCorresponding absorbance A _s, as shown in table 2.

τ _s=τ-Δτ _s （5）

Value comparison before and after table 2 gamma correction

(b) Criterion curve: the transmittance indicating value of (6) first order calculation standard substance by formula, after by formula gamma correction is carried out in (4), (5), the transmission ratio τ of the material that settles the standard _s, and calculate corresponding absorbance A _si, as shown in table 3.

$\mathrm{\&tau;}=\frac{U_s}{{\mathrm{<figure-callout\; id="0"\; label="U"\; filenames="HDA00003258768900013.png"\; state="\{\{state\}\}">U</figure-callout>}}_0}\&times;100\%---\left(6\right)$

In formula: τ--standard substance transmittance indicating value,

U _s--sample is placed in the signal indicating value of light path,

U ₀--the signal indicating value when light path is blank;

Table 3 measurement mechanism c _iWith A _siCorresponding relation

Numbering	c i/%	A si
			1	0.0122	0.0153
2	0.0292	0.0385
			3	0.0558	0.0726
4	0.1098	0.1457
			5	0.1990	0.2660
6	0.2832	0.3668

According to c in table 3 _iWith A _siCorresponding relation, set up the typical curve of measurement mechanism:

c=0.7649．A _s-0.0005 （7）

(c) measure and the data processing: by formula (6) calculate the transmission ratio τ of testing sample, after gamma correction, calculate the absorbance A of testing sample _s, reference standard curve (7) provides the corresponding water content of testing sample.

The signal fluctuation that the unevenness that measurement mechanism adopts integrating sphere to reduce the photosurface of the unevenness of monochromatic light light beam and detector causes, after adopting the diplopore method to carry out gamma correction to the transmittance indicating value of device, maximum absorbance value deviation is 1/4 before proofreading and correct, according to typical curve (7), and N ₂O ₄The accuracy of corresponding water content measurement mechanism can improve more than 3 times.

Embodiment two

The structure of twin-beam measurement mechanism adds synchronization wave cutter 7,10 as shown in Figure 2 on the basis of embodiment one, and plane mirror 8,9 forms, chopper is parallel with plane mirror, and optical axis is in same plane, and the spacing of sample chamber 4, plane mirror 9, chopper 10, integrating sphere 5 equates.

Measurement mechanism carries out gamma correction in the single beam mode, makes the light through spectacle plate 3 reflex to plane mirror 9 through chopper 7, through the sample chamber 4 and chopper 10 be pooled to integrating sphere 5.When Criterion curve and measurement, the emergent light of monochromator consists of reference light paths through chopper 7, plane mirror 8, chopper 10, consist of the sample light path through chopper 7, plane mirror 9, sample chamber 4, chopper 10, the transmittance indicating value τ of (9) calculation sample by formula, additive method is identical with embodiment one.

$\mathrm{\&tau;}=\frac{U_s}{U_r}\&times;100\%---\left(9\right)$

In formula: τ--the transmittance indicating value before gamma correction,

U _s--the signal indicating value of sample light path,

U _r--the signal indicating value of reference light paths.

Claims (5)

1. spectroscopic methodology N ₂O ₄Middle corresponding water content measurement mechanism, it is characterized in that: formed by bright pink outer analysis instrument, spectacle plate (3) and integrating sphere (5), spectacle plate (3) is comprised of A, B hole, the Area Ratio N in B hole and A hole is between 1.5～5, spectacle plate (3) is placed in the parallel light path between monochromator exit slit and sample chamber, integrating sphere (5) is placed in the parallel light path behind the sample chamber, incident light is perpendicular to the integrating sphere incidence window, the photosurface of near infrared photodetector (6) overlaps with the integrating sphere inside surface, and incident light is the photosurface of direct irradiation detector (6) not.

2. spectroscopic methodology N according to claim 1 ₂O ₄Middle corresponding water content measurement mechanism is characterized in that: be comprised of bright pink outer analysis instrument, spectacle plate (3) and integrating sphere (5), bright pink outer analysis instrument adopts the twin-beam light path; Spectacle plate (3) is comprised of A, B hole, the Area Ratio N in B hole and A hole is between 1.5～5, spectacle plate (3) is placed in the parallel light path between monochromator exit slit and sample chamber, integrating sphere (5) is placed in the parallel light path behind the sample chamber, incident light is perpendicular to the integrating sphere incidence window, the photosurface of near infrared photodetector (6) overlaps with the integrating sphere inside surface, and incident light is the photosurface of direct irradiation detector (6) not.

3. the N of described spectroscopic methodology according to claim 1 and 2 ₂O ₄Middle corresponding water content measurement mechanism is characterized in that: described integrating sphere (5) is spherical structure, and window area is not more than 5% of integrating sphere inner surface area.

4. N according to claim 3 ₂O ₄Middle corresponding water content measurement mechanism is characterized in that: the reflectivity of described integrating sphere inside surface is not less than 80%.

5. spectroscopic methodology N according to claim 1 and 2 ₂O ₄Middle corresponding water content measurement mechanism is characterized in that: in described spectacle plate, the Area Ratio N in B hole and A hole is between 2～3.

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