CN204758471U - Water turbidity measurement system based on gating double light path - Google Patents

Abstract

The utility model discloses a water turbidity measurement system based on gating double light path, including water turbidity signal acquisition module, signal processing module, control module and display module, water turbidity signal acquisition module includes light source generator, first spectroscope, second spectroscope, first level crossing, second level crossing, first baffle, second baffle, measuring flume, convex lens and photoelectric detector. The utility model discloses eliminate the turbidity measuring error and the inconsistent error that causes of a plurality of detector performance that lead to owing to the flashing.

Description

Based on the water turbidity measuring system of gating double light path

Technical field

The utility model belongs to liquid turbidity field of measuring technique, particularly based on the water turbidity measuring system of gating double light path.

Background technology

The turbidity of water is a kind of optical effect in water sample, refers to that the solid particulate matter and impurity that suspend in water sample are to the degree of the water sample transparency change caused by the scattering of light and absorption.In recent years, water pollution event happens occasionally and threatens the life and health of the vast name masses, and this causes the popular care to water quality monitoring undoubtedly.Bring, the water quality condition how measuring field water seedbed has just become an important problem rapidly anti-interferencely thereupon.

According to turbidimetry international standard ISO7027, the measurement of turbidity measures scattered light on 90 ° of directions, and this measuring method has good linear relationship in low turbidity region, but result in measuring error because scattered light creates rescattering in high concentrtion region.In water body in the wild, water turbidity is generally easier to produce rescattering effect, makes measuring error larger.Therefore market is generally realize Turbidity measurement by the transmitted light that measuring error is less.And on the other hand, in actual measurement, although the turbidimeter of single light source monochromatic light road type is simple and practical, but its remarkable shortcoming is the increase along with device service time, the stability of light source can be deteriorated, its light intensity sent and theoretical value can there are differences, and photodetector makes hydraulic performance decline along with the change of temperature and the stained of surface, causes the error of measured value and actual value.

In utility model (publication number: CN103454252A) disclosed in, utility model people have employed the mode that single light source 90 ° of scatterings combine with measurement script light intensity, the light of sampling scattered light and light source simultaneously, to solve the error caused due to flashing.But because this measuring method have employed two detectors, therefore inconsistent the brought measuring error of the different and multiple photodetector detection performance of the stained situation caused at diverse location because of different electric explorer cannot be solved.Its scattered light method selected measures turbidity when high concentrtion simultaneously, and the cause due to rescattering makes error comparatively large, and thus the measurement range of the program is restricted.

Utility model content

In order to solve the technical matters that above-mentioned background technology proposes, the utility model aims to provide the water turbidity measuring system based on gating double light path, eliminates the error of the turbidimetry caused due to flashing and inconsistent the caused error of multiple detector performance.

In order to realize above-mentioned technical purpose, the technical solution of the utility model is:

Based on the water turbidity measuring system of gating double light path, comprise water turbidity signal acquisition module, signal processing module, control module and display module; Described water turbidity signal acquisition module comprises light source generator, the first spectroscope, the second spectroscope, the first level crossing, the second level crossing, the first baffle plate, second baffle, measuring flume, convex lens and photodetector; Described first spectroscope, the first baffle plate, the second spectroscope and convex lens are arranged in the same horizontal line successively, described first spectroscope, second baffle and the first level crossing are arranged on same pedal line successively, described first level crossing, measuring flume and the second level crossing are arranged in the same horizontal line successively, described second spectroscope and the second level crossing are positioned on same pedal line, fill testing liquid in described measuring flume; Described control module connects the actuation mechanism of the first baffle plate and second baffle respectively to control the rotation of the first baffle plate and second baffle; Described light source generator is to the first spectroscope emission of light, and this light is divided into the first light splitting in the horizontal direction and the second light splitting along vertical by the first spectroscope; When the first baffle plate turns to the position of not blocking the first light splitting, the first light splitting is incident second spectroscope and convex lens successively; When second baffle turns to the position of not blocking the second light splitting, the second light splitting is incident first level crossing, measuring flume, the second level crossing, the second spectroscope and convex lens successively; The input end of described photodetector gathers the light signal of convex lens injection, and the output terminal of photodetector is connected successively with signal processing module, control module and display module.

Wherein, the top of above-mentioned measuring flume has water inlet, and the bottom of measuring flume has water delivering orifice; Measuring flume is provided with at least one pair of baffle near the inwall of water inlet, and this is separately positioned on the inwall of measuring flume both sides to piece baffle of two in baffle, and every block baffle and the inwall angle near water inlet side are between 45 ° ~ 75 °; Measuring flume is provided with at least one pair of baffle near the inwall of water delivering orifice, and this is separately positioned on the inwall of measuring flume both sides to piece baffle of two in baffle, and every block baffle and the inwall angle near water delivering orifice side are between 45 ° ~ 75 °.

Wherein, above-mentioned light source generator sends the near infrared light of 860nm.

Wherein, above-mentioned first spectroscope, the second spectroscope are raster pattern spectroscope.

Wherein, above-mentioned photodetector adopts phototriode.

Wherein, above-mentioned signal processing module comprises the amplifying circuit, filtering circuit and the AD converter that connect successively, and the input end of described amplifying circuit connects the output terminal of photodetector, the output terminal link control module of AD converter.

Adopt the beneficial effect that technique scheme is brought:

(1) transmitted light of the utility model measurement through testing liquid and the light of script light source, can reduce the stained measuring error caused of flashing and detector effectively, can after working long hours, and retention is stablized;

(2) the utility model is by the gated fashion of baffle plate, a photodetector can be utilized to detect two physical quantitys, reduce the inherent error utilizing multiple detector to cause;

(3) the utility model detection sensitivity is high, and integrated level is higher, more compact structure, can realize the on-line quick detection of water turbidity under complicated environmental condition.

Accompanying drawing explanation

Fig. 1 is system architecture diagram of the present utility model;

Fig. 2 is water turbidity signal acquisition module structural representation in the utility model;

Fig. 3 is the structural representation of measuring flume in the utility model.

Label declaration: 1, light source generator; 2, the first spectroscope; 3, the first level crossing; 4, the second level crossing; 5, measuring flume; 6, the second spectroscope; 7, the first baffle plate; 8, second baffle; 9, convex lens; 10, photodetector; 11, baffle; 12, water inlet; 13, water delivering orifice.

Embodiment

Below with reference to accompanying drawing, the technical solution of the utility model is described in detail.

System architecture diagram of the present utility model as shown in Figure 1, based on the water turbidity measuring system of gating double light path, comprises the water turbidity signal acquisition module, signal processing module, control module and the display module that connect successively.Described water turbidity signal acquisition module as shown in Figure 2, comprise light source generator 1, first spectroscope 2, second spectroscope 6, first level crossing 3, second level crossing 4, first baffle plate 7, second baffle 8, measuring flume 5, convex lens 9 and photodetector 10, described first spectroscope, first baffle plate, second spectroscope and convex lens are arranged in the same horizontal line successively, described first spectroscope, second baffle and the first level crossing are arranged on same pedal line successively, described first level crossing, measuring flume and the second level crossing are arranged in the same horizontal line successively, described second spectroscope and the second level crossing are positioned on same pedal line, testing liquid is filled in described measuring flume, described control module connects the actuation mechanism of the first baffle plate and second baffle respectively, control their rotation.Described light source generator 1 is to the first spectroscope transmitted beam, this light beam is divided into the first light splitting transmitted in the horizontal direction and the second light splitting transmitted along vertical by the first spectroscope, when the position of the first plate washer not facing the first spectroscope, first light splitting can incident second spectroscope, first light splitting is divided into transmission in the horizontal direction and the two-beam along vertical transmission by the second spectroscope, wherein light beam planoconvex lens converges rear directive photodetector in the horizontal direction, when the position of second baffle not facing the first spectroscope, second light splitting can incident first level crossing, first level crossing changes the transmission direction of the second light splitting, make it incident measuring flume in the horizontal direction, the second level crossing is injected in second light splitting after measuring flume, second level crossing changes the transmission direction of the second light splitting again, make it along incident second spectroscope of vertical, second light splitting is divided into transmission in the horizontal direction and the two-beam along vertical transmission by the second spectroscope, wherein light beam planoconvex lens in the horizontal direction converge after directive photodetector.The input end of described photodetector gather convex lens injection light signal and after this light signal being converted to electric signal mirror signal processing module send into control module, control module calculates the turbidity value of testing liquid according to electric signal, and shows on display module.

In the present embodiment, the top of described measuring flume has water inlet 12, and the bottom of measuring flume has water delivering orifice 13, can reduce the flow velocity of water like this, avoids the generation of bubble; Measuring flume is provided with at least one pair of baffle 11 near the inwall of water inlet, and this is separately positioned on the inwall of measuring flume both sides to piece baffle of two in baffle, and every block baffle and the inwall angle near water inlet side are between 45 ° ~ 75 °; Measuring flume is provided with at least one pair of baffle near the inwall of water delivering orifice, and this is separately positioned on the inwall of measuring flume both sides to piece baffle of two in baffle, and every block baffle and the inwall angle near water delivering orifice side are between 45 ° ~ 75 °.These baffles make the bubble in water body adhere to, and avoid bubble on the impact of turbidimetry.

In the present embodiment, light source generator sends the near infrared light of 860nm, can reduce the impact of colourity for turbidimetry of water sample to greatest extent; First spectroscope, the second spectroscope all adopt raster pattern spectroscope, the monochromatic light sent by light source generator is divided into the light of two bundle same frequencys of known light intensity proportionate relationship, it is roughly equal that raster pattern spectroscope produces the assorted district of spectrum, and red light district resolution is higher than lens type; Photodetector adopts phototriode, and phototriode sensitivity is higher, and volume is little, and power consumption is little, and it is overheated to be not easy to, and does not need too much cooling device.

In the present embodiment, signal processing module comprises the amplifying circuit, filtering circuit and the AD converter that connect successively, and the input end of described amplifying circuit connects the output terminal of photodetector, the output terminal link control module of AD converter.

The light that light source generator sends by the first spectroscope is divided into the first light splitting I _awith the second light splitting I _b, when the first baffle plate does not block I _alight path, I _aafter the second spectroscope, the light splitting I of its horizontal direction _a1incident convex lens, and by photoelectric detector, when second baffle does not block I _blight path, I _bincident second spectroscope after the first level crossing, measuring flume, the second level crossing successively, the light splitting I of its horizontal direction _b1incident convex lens, and by photoelectric detector.I _awith I _bfor same light source is by the light wave of two bundle same frequencys of the known light intensity proportionate relationship of the first spectroscope 2 generation.And I _a1with I _b1i _awith I _blight after the second spectroscope 6.I _b1with I _a1business α and currently treat that the turbidity of sample measuring liquid has certain funtcional relationship:

$\mathrm{\α}=\frac{I_{b1}}{I_{a2}}=\frac{S_{a1}}{S_{b1}}---\left(1\right)$

Wherein, S _a1, S _b1for light beam I _aand I _bmagnitude of voltage after photodetector carries out opto-electronic conversion.

According to Bill's Lambert law law, can obtain:

$\mathrm{\α}=\frac{{\mathrm{\β}}_1{I}_a{e}^{-\mathrm{\ϵ}TL}}{{\mathrm{\β}}_2{I}_b}---\left(2\right)$

Wherein, β ₁with β ₂be second spectroscopical point of backscatter extinction logarithmic ratio, ε is the constant relevant with the composition of testing liquid, character, and L is light path, and T is the turbidity value of testing liquid.

Due to I _awith I _bproportionate relationship known, be I _a=mI _b, (3)

Formula (3) is substituted into formula (2) can obtain $\mathrm{\α}=\frac{{\mathrm{\β}}_1{I}_a{e}^{-\mathrm{\ϵ}TL}}{{\mathrm{\β}}_2{I}_b}=\frac{{\mathrm{\β}}_1{\mathrm{mI}}_b{e}^{-\mathrm{\ϵ}TL}}{{\mathrm{\β}}_2{I}_b},---\left(4\right)$

Formula (4) abbreviation can be obtained $\mathrm{\α}=\frac{{\mathrm{\β}}_1{\mathrm{me}}^{-\mathrm{\ϵ}TL}}{{\mathrm{\β}}_2}={\mathrm{Ae}}^{-\mathrm{\ϵ}TL},---\left(5\right)$

By formula (5) known α and e ^{-ε TL}be directly proportional, then can pass through I _a1with I _b1ratio α try to achieve the turbidity value T of testing liquid.

The ratio obtained in this way and the size of light source have nothing to do, simultaneously owing to then there is not the inherent error of multidetector for single photo-detector, constantly switch gating light path in real time simultaneously, make the state forming a kind of self-calibration, then the stained value to measuring of detector also can not have an impact.

Based on the measuring method of above-mentioned water turbidity measuring system, concrete steps are as follows:

1, open water inlet and the water delivering orifice of measuring flume, in measuring flume, be slowly charged into testing liquid.

2, start photodetector and carry out preheating before measuring, after the temperature stabilization of photodetector, measure.

3, light source generator exports corresponding frequencies light beam, the first light splitting and the second light splitting is produced through the first spectroscope, control module controls the light path that the first baffle plate blocks the first light splitting, and control the light path that second baffle does not block the second light splitting, after 1min, inverse operation, control module controls the light path that second baffle blocks the second light splitting, and control the light path that the first baffle plate does not block the first light splitting, the light signal that twice operation receives is converted to electric signal by photodetector, and sends this electric signal to control module through signal processing module.

4, two electric signal demodulation are obtained relevant voltage value by control module, calculate the ratio of two magnitudes of voltage and substitute in the variation relation curve of standard turbidity value and magnitude of voltage ratio, obtaining testing liquid turbidity value, and turbidity value are sent to display module display.

Wherein, the variation relation curve of standard turbidity value and ratio inverse can be obtained by following process: be filled with successively in measuring flume by the formal hydrazine solution of several various criterion, record its corresponding magnitude of voltage respectively, and ratio calculated, using ratio and standard turbidity value as transverse and longitudinal coordinate, draw both relation curves, because both are exponential relationship, therefore the index of ratio and standard turbidity value is demarcated.And utilize least square method to carry out linear fit: y=kx+b, wherein, x represents ratio, y represents the exponential quantity of standard turbidity value, k and b is linear fit parameter, obtains the value of parameter k and b, draws matched curve, the i.e. exponential quantity of standard turbidity value and the variation relation of ratio, as long as will to measure and the ratio calculated substitutes in above-mentioned variation relation curve and just can push away to obtain the size of turbidity.

Above embodiment is only and technological thought of the present utility model is described; protection domain of the present utility model can not be limited with this; every technological thought according to the utility model proposes, any change that technical scheme basis is done, all falls within the utility model protection domain.

Claims (6)

1. based on the water turbidity measuring system of gating double light path, it is characterized in that: comprise water turbidity signal acquisition module, signal processing module, control module and display module; Described water turbidity signal acquisition module comprises light source generator, the first spectroscope, the second spectroscope, the first level crossing, the second level crossing, the first baffle plate, second baffle, measuring flume, convex lens and photodetector; Described first spectroscope, the first baffle plate, the second spectroscope and convex lens are arranged in the same horizontal line successively, described first spectroscope, second baffle and the first level crossing are arranged on same pedal line successively, described first level crossing, measuring flume and the second level crossing are arranged in the same horizontal line successively, described second spectroscope and the second level crossing are positioned on same pedal line, fill testing liquid in described measuring flume; Described control module connects the actuation mechanism of the first baffle plate and second baffle respectively to control the rotation of the first baffle plate and second baffle; Described light source generator is to the first spectroscope emission of light, and this light is divided into the first light splitting in the horizontal direction and the second light splitting along vertical by the first spectroscope; When the first baffle plate turns to the position of not blocking the first light splitting, the first light splitting is incident second spectroscope and convex lens successively; When second baffle turns to the position of not blocking the second light splitting, the second light splitting is incident first level crossing, measuring flume, the second level crossing, the second spectroscope and convex lens successively; The input end of described photodetector gathers the light signal of convex lens injection, and the output terminal of photodetector is connected successively with signal processing module, control module and display module.

2., according to claim 1 based on the water turbidity measuring system of gating double light path, it is characterized in that: the top of described measuring flume has water inlet, the bottom of measuring flume has water delivering orifice; Measuring flume is provided with at least one pair of baffle near the inwall of water inlet, and this is separately positioned on the inwall of measuring flume both sides to piece baffle of two in baffle, and every block baffle and the inwall angle near water inlet side are between 45 ° ~ 75 °; Measuring flume is provided with at least one pair of baffle near the inwall of water delivering orifice, and this is separately positioned on the inwall of measuring flume both sides to piece baffle of two in baffle, and every block baffle and the inwall angle near water delivering orifice side are between 45 ° ~ 75 °.

3., according to claim 1 based on the water turbidity measuring system of gating double light path, it is characterized in that: described light source generator sends the near infrared light of 860nm.

4. according to claim 1 based on the water turbidity measuring system of gating double light path, it is characterized in that: described first spectroscope, the second spectroscope are raster pattern spectroscope.

5. according to claim 1 based on the water turbidity measuring system of gating double light path, it is characterized in that: described photodetector adopts phototriode.

6. according to claim 1 based on the water turbidity measuring system of gating double light path, it is characterized in that: described signal processing module comprises the amplifying circuit, filtering circuit and the AD converter that connect successively, the input end of described amplifying circuit connects the output terminal of photodetector, the output terminal link control module of AD converter.