CN1312467A - Oil measurer with multiple wavelenglth optical filter array detector - Google Patents

Abstract

The instrument for detecting oil content of mineral comprises light source, power supply, modulator, liquid core waveguide absorption cell, multiwavelength filter, array detector, signal processing circuit and chip microprocessor system. The light feedback system capable of directly controlling light, modulator formed from crystal oscillator and chip microprocessor, liquid core waveguide absorption cell with low refractivity and oleophobic and hydrophobic long tube body and spectrum retina can make the invented instrument possess high sensitivity, high precision, high accuracy, good stability, short analysis time, small volume, light weight, simple operation and convenient use, etc.

Description

Oil measurer with multiple wavelenglth optical filter array detector

The invention belongs to a kind of measurement mechanism, particularly measure the instrument of mineral oil content.

Along with a large amount of exploitations of mineral fuel be extensive use of, mineral oil has become a whole world problem that pay close attention to, more and more serious to the pollution of water body and environment, and is no exception in China, now become one of major pollutants of China's environment water.Owing to contain respectively at 2930cm in the mineral oil composition ^-1, 2960cm ^-1And 3030cm ^-1The different component that absorption peak is arranged, thereby, in order accurately to measure the content of mineral oil, need above-mentioned three absorption peaks are measured.

The device close with oil content analyzer of the present invention is multi-functional Infrared Oil Determination Instrument.Multi-functional Infrared Oil Determination Instrument partly is made up of light source chamber, modulator, sample chamber, monochromator, infrared detection system and stabilized voltage supply, signal processing circuit, driving circuit, display, printer etc.Concrete structure can be referring to Fig. 1 and Fig. 2.They are respectively the principle of work block scheme and the optical system schematic diagram of prior art.Among the figure, 1 is power supply, adopts source of stable pressure to give light source 2 power supplies.Light source 2 is tungsten halogen lamps of good stability.3 is modulator, is made up of parts such as chopper wheel 20, synchronous motor and photoelectric coupling circuits, realizes the modulation of light signal and provides synchronizing signal to testing circuit.4 is the sample chamber, is made of absorption cell 24, support plate, sample switching mechanism.Measured sample is receiving optical signals in absorption cell.This instrument adopts the monochromatic light line structure, reference, sample enter light path successively and measure, automatically switch by programmed control reference and sample, the sample switching mechanism adopts the screw gear gear train of stepper motor drive and realizes high-precision location in conjunction with optoelectronic switch, the support plate that is loaded with absorption cell 24 is along the to-and-fro movement of vertical optical axis direction, thereby realization is switched the position of absorption cell 24.5 is monochromator, constitutes sweep limit 3400cm by collimator objective, cosecant type Wavelength scanning mechanism, grating, image-forming objective lens, cutoff filter, entrance slit and exit slit ^-1To 2400cm ^-16 is detecting device, belongs to TGS type pyroelectricity detecting device.7 is signal processing circuit, finishes frequency-selecting amplification, synchronous detection and the analog-digital conversion function of electric signal.Last signal carries out analyzing and processing by Single Chip Microcomputer (SCM) system, and this system comprises single-chip microcomputer 8, LCD 9, printer 10, keyboard 11 etc.In addition, 12 is stepper motor driving circuit, and it accepts single-chip microcomputer 8 control signals and drive stepping motor is rotated the sample switching mechanism of sample chamber 4 and the grating of monochromator 5.Optical system is light source 2, modulator 3, catoptron 21, condenser 22 by the optical propagation direction order, absorption cell 24, and light converges in entrance slit 25 afterwards.After light beam enters monochromator 5, through collimator objective 26, grating 27, imaging object lens 28, with the monochromatic spectrum imaging on exit slit 29.Pass through cutoff filter 30, ellipsoidal mirror 31 at last, monochromatic spectrum is converged on the TGS crystal 32 of detector 6 windows.

The deficiencies in the prior art part shows: instrumental sensitivity is lower, be difficult to satisfy the detection of low content samples such as surface water, by Lambert-Beer's law as can be known, the effective path length of absorption of sample is directly proportional with the sensitivity of instrument detecting, the effective path length of existing instrument absorption cell is subjected to the restriction of space and material, has only about 4cm.Owing to be monochromatic light road scanning survey instrument, the switching of sample, reference be carried out, and the information at two above wavelength places can not be obtained simultaneously, analysis speed is slow.Mechanically operated switching mechanism can cause the difference of light path luminous flux and precision of measurement to reduce unavoidably; Owing to light source stability is required height, and working current is bigger, uses the inaccessible stable requirement of voltage stabilizing powering mode.

The present invention is for overcoming the deficiencies in the prior art, reaches to increase effective light path and improve detection sensitivity, improves accuracy of detection, accuracy and can obtain the purpose that two above wavelength place information improve analysis speeds simultaneously.

The object of the present invention is achieved like this, adopts the liquid core waveguide absorption cell to increase effective light long-range, improves and measure sensitivity; Adopt spectrum retina technology, promptly adopt multi-wavelength optical filter and array detector, realize the while high-precision information in more accurate acquisition two above wavelength place (signal to noise ratio (S/N ratio) is directly proportional with the square root of the number of detecting unit) thereby the raising analysis speed; Thereby do not have mechanisms such as mechanical transmission, mechanical positioning and improve measuring accuracy to greatest extent.

Structure of the present invention is provided by Fig. 3, Fig. 4, and concrete structure is described below:

Among Fig. 3,1 is power supply, is light source 2 power supplies, adopts i.e. " steady light " mode of operation of light feedback system between power supply of the present invention and the light source, makes light source 2 luminous more stable; Light source 2 is a tungsten halogen lamp; Light source 2 places install condenser additional, improve the utilization factor of light source; 3 is modulator, and the optical modulation that light source 2 is sent becomes the square wave light signal; Light source 2 and modulator 3 all adopt 12 volts of direct current supplys portablely to use.Modulator 3 adopts high-precision crystal oscillator to provide accurate frequency to make modulating frequency more stable, the phase place of detection can be regulated by single-chip microcomputer is convenient, the detection synchronizing signal of pin-point accuracy, high precision is provided, thereby guarantees that the detection performance of complete machine and the machine of reduction chopper wheel 20 add difficulty.Press the light order of propagation, be respectively liquid core waveguide absorption cell 40, multi-wavelength optical filter 41, array detector 42 thereafter.The main body of liquid core waveguide absorption cell 40 is one section body 44 of sealing.It can be that (refractive index should less than 1.33) synthetic, low-refraction, the hydrophobic material of oleophobic blow to draw and form, and adorns detected liquid in the body, and light is propagated by the duct propagation rule within it.Because it is very long and flexible that body can make, obtain very long effective light path when volume can be reduced.Multi-wavelength optical filter 41 is that the rete of producing two or more wavelength on substrate constitutes, and is installed in the oil content analyzer light path, can be interrupted to change or change continuously in very big wavelength coverage; Array detector 42 is pyroelectricity detecting devices, is two detecting devices that above detecting unit is integrated, and the detecting device that promptly can adopt linear array or face battle array to arrange as required can obtain the whole spectral informations in the design field simultaneously.Cooperating coupling by multi-wavelength optical filter 41 with array detector 42, be called spectrum retina technology, is the basis of spectrometer miniaturization.Testing circuit is by signal processing circuit 7, single-chip microcomputer 8, and LCD 9, printer 10, keyboard 11 is formed.Before each ingredient of the present invention of chatting, be respectively individual member, their position relation is by the optical system decision of design.

Compared with the prior art, saved stepper motor driving circuit 12 and sample switching mechanism etc., made various member of the present invention be fixed component, thereby improved the measuring accuracy and the stability of instrument, be easy to carry.

Among Fig. 4,44 is the absorption cell body, can make of polytetrafluoroethylmaterial material, and its refractive index is less than the refractive index of detected sample such as optical transmission medium phenixin, zellon.Its two ends are installed in the metallic sheath 47.Metallic sheath 47 is a hollow, both ends open, the end absorption cell body 44 of packing into, and the relative other end is equipped with optical coupling element 48.For fixed optics coupling element 48 and absorption cell body 44, and to accomplish sealing, trim ring 49 is housed, sealed liner 50 is housed in metallic sheath 47 in optical coupling element 48 outsides.For the sample of packing into, sample introduction pipe 45 also is housed respectively on the metallic sheath 47 at absorption cell body 44 two ends, go out sample pipe 46.Adopt PROGRAMMED AUTO or hand gun that sample is introduced mechanism, thus the pollution of avoiding the organic solvent exposed to air to bring, and operating personnel directly do not contact organic reagent in measurement simultaneously, make operation become safe and simple.Liquid core waveguide absorption cell 40 among the present invention has increased effective light path greatly, and has improved measurement sensitivity, and simultaneously, amount of samples is few, can realize continuous monitoring.

Light feedback system between power supply of the present invention and the light source is made of optical sensor, control circuit and regulating circuit.The i.e. radiation of the specific band that light source is sent with sensor is converted to electric signal, and compares with reference signal, obtains adjusting signal and removes the regulating and controlling circuit, regulates supply current, makes the radiation intensity of light source 2 stable.Overcome the light radiation intensity labile factor that the indirect control model of stabilized voltage supply causes in the prior art, thus real realization the " steady light ".

Description of drawings:

Fig. 1 is the principle of work block diagram of prior art.

Fig. 2 is the optical system schematic diagram of prior art.

Fig. 3 is a principle of work block diagram of the present invention.

Fig. 4 is the structural representation of liquid core waveguide absorption cell of the present invention.

Multi-wavelength filter arrays detection type oil content analyzer of the present invention is owing to adopt 12 volts of DCs Electricity adopts liquid Core Waveguide Technique, and has reduced the stepper motor driving mechanism. Thereby volume is little. Heavy Amount is light, is easy to carry, and is applicable to open-air the detection. Because no movable member improves to greatest extent Stability and the certainty of measurement of instrument. Greatly improved detection owing to use liquid Core Waveguide Technique Sensitivity, remolding sensitivity prior art improve 5-10 doubly. Owing to carry out simultaneously two above wavelength Measurement, greatly shortened analysis time, can obtain simultaneously total mineral oil or alkane and aromatic hydrocarbon and contain The testing result of amount, simple to operate, and can realize that the mineral oil in online and the continuous monitoring water body contains Amount.

Claims (4)

1, a kind of multi-wavelength filter arrays detection type oil content analyzer, by light source (2), the modulator (3) that the light that light source (2) is sent is modulated is the power supply (1) of the motor power supply of light source (2) and modulator (3), and signal processing circuit (7), Single Chip Microcomputer (SCM) system constitutes; It is characterized in that by the light path order, modulator (3) is the liquid core waveguide absorption cell afterwards, is multi-wavelength optical filter (41) and the array detector (42) that constitutes spectrum retina technology after again; Said multi-wavelength optical filter (41) is that the rete of producing two or more wavelength on substrate constitutes, to the light interruption or the optical filtering continuously of certain wavelength coverage; Array detector (42) is two integrated detecting devices of above detecting unit of pyroelectricity, through array detector (42) each monochromatic light signal is become electric signal and passes to signal processing circuit (7).

2, according to the described multi-wavelength filter arrays of claim 1 detection type oil content analyzer, it is characterized in that, the structure of liquid core waveguide absorption cell (40) comprises sealing, the body (44) that refractive index is made less than 1.33 oleophobic hydrophobic material, detected liquid time obedience waveguide mechanism is housed in the body (44), the metallic sheath (47) of hollow respectively is equipped with at the body two ends, metallic sheath (47) the one ends absorption cell body (44) of packing into, the relative other end is equipped with optical coupling element (48), in optical coupling element (48) outside trim ring (49) is housed, sealed liner (50) is housed in the metallic sheath (44), sample introduction pipe (45) also is housed respectively on two metallic sheaths (47) at absorption cell body (44) two ends and goes out sample pipe (46).

According to claim 1 or 2 described multi-wavelength filter arrays detection type oil content analyzers, it is characterized in that 3, the light feedback system of directly steady light is housed, and it is made of optical sensor spare, control circuit and circuit conditioning circuit between light source (2) and power supply (1).

According to claim 1 or 2 described multi-wavelength filter arrays detection type oil content analyzers, it is characterized in that 4, modulator (3) is made of Single Chip Microcomputer (SCM) system, photo-coupler, the driving circuit that has crystal oscillator, stepper motor and chopper wheel (20).