CN105136984A - Detection device and method for volatile methanol in experimental environment - Google Patents

Abstract

The invention discloses a detection device and method for volatile methanol in an experimental environment. The detection device comprises a controller, a memory, and a bottom board, a gas chamber with a rectangular cross section and a support frame that are arranged on the bottom board, and a guide structure and a transverse screw rod that are disposed on the support frame. The gas chamber inner wall top is equipped with several fans for blowing air downward, the upper part of the gas chamber is internally equipped with a first metal net and a second metal net that are composed of heating wires, several gas sensitive films in interval distribution are arranged between the first metal net and the second metal net, the gas chamber below the second metal net is internally provided with a horizontal partition plate dividing the gas chamber into an upper part and a lower part, and a detection head is provided with an MQ-2 sensor, an MQ-135 sensor and a methanol sensor. The detection device and method provided by the invention have the characteristics of high sensitivity, good stability and short response time, good selectivity to methanol, detectability of lower concentration trace methanol gas, and effective guarantee of people's health.

Description

To volatilize in laboratory environment methanol detection device and method

Technical field

The present invention relates to Environmental security technical field, especially relate to a kind of can fast, accurately in test experience room environmental methanol concentration laboratory environment in volatilize methanol detection device and method.

Background technology

The toxicity of methyl alcohol has the greatest impact to the nervous system of human body and hematological system, and it is taken in through alimentary canal, respiratory tract or skin all can produce toxic reaction, the respiratory mucosa that methanol vapor energy loss victimizes and eyesight.

Acute poisoning symptom has: headache, feel sick, stomachache, tired, eye-blurred so that blind, then have difficulty in breathing, finally cause respiratory center to be benumbed and dead.Slow poisoning reaction is: dizzy, lethargic sleep, headache, tinnitus, hypopsia, gastricism.

At present low concentration methanol detection method is mainly relied on to the method for instrumental analysis, as vapor-phase chromatography etc.Although above-mentioned detection method can the concentration of Trace Methanol in testing environment accurately, but the deficiencies such as ubiquity sense cycle length, cost intensive, and, need the those of skill in the art's operating instrument equipment through professional training, the scene of Trace Methanol in environment that cannot realize accurately is detected fast.

Therefore, the detection system for Trace Methanol used at present exists that sensitivity is low, poor selectivity, poor stability or can not the problem of Long-Time Service.

Chinese patent Authorization Notice No.: CN101846610A, authorized announcement date on September 29th, 2010, disclose a kind of gas-detecting device and gas detecting system, it comprises quartz plate, first electrode, second electrode and adsorbed layer, described quartz plate has relative first surface and second surface, described first electrode is formed at first surface, described second electrode is formed at second surface, described adsorbed layer is formed at the first electrode surface, described adsorbed layer is made up of iridium-iridium dioxide nanometer rods, for adsorbing gas to be detected, change to make the quality of gas-detecting device, thus obtain the concentration of gas to be detected.It is slow to there is detection speed in this invention, the deficiency that accuracy of detection is low.

Summary of the invention

The present invention is that the sense cycle in order to overcome gas detection method of the prior art is long, cost is high, the deficiency of apparatus expensive, provide a kind of can fast, accurately in test experience room environmental methanol concentration laboratory environment in volatilize methanol detection device and method.

To achieve these goals, the present invention is by the following technical solutions:

Volatilize in a kind of laboratory environment methanol detection device, comprises controller, storer, base plate, is located at the rectangular air chamber of xsect on base plate and bracing frame, is located at the guide frame on bracing frame and cross lead screw;

Described air chamber inwall top is provided with for several fans to canyon, the first wire netting and the second wire netting that are made up of heating wire is provided with in air chamber top, the gas sensitization film of some block gaps distribution is provided with between first wire netting and the second wire netting, be provided with for air chamber being divided into upper and lower two-part horizontal baffle in the air chamber of the second wire netting bottom, air chamber inner bottom part is provided with supporting plate, detection head and the track along splint upper surface Spiral distribution, and detection head is provided with MQ-2 sensor, MQ-135 sensor and methanol sensor;

Cross lead screw one end is connected with the rotating shaft of the first motor be located on bracing frame, described air chamber is provided with the opening for inserting horizontal baffle, horizontal baffle outer end is provided with web joint, detection head bottom is provided with the second motor for driving detection head orbital motion, web joint is connected with wire rod thread, web joint and guide frame are slidably connected, and the air chamber being positioned at horizontal baffle upper and lower is respectively equipped with one group of draft tube and escape pipe; Draft tube and escape pipe are equipped with solenoid valve; Hermetically-sealed construction is provided with between opening and horizontal baffle;

Controller is electrically connected with storer, each electric fan, each solenoid valve, the first wire netting, the second wire netting, the first motor, the second motor, MQ-2 sensor, MQ-135 sensor and methanol sensor respectively.

Gas sensitization film is used for adsorption experiment room gas, and gas sensitization film has gas inrichment, can by gas sensitization film successively ultrasonic cleaning 15min in HNO3 (1: 1), acetone and distilled water, and the electrode after cleaning dries for subsequent use under being placed in room temperature; Mixed with polyglycol solution by cider by a certain percentage, evenly obtain potpourri with sonic oscillation, drawing 5 μ L massfractions with micro syringe is the potpourri of 5%Nafion, drips and is applied to gas sensitization film surface, dry stand-by under room temperature.

First wire netting and the second wire netting are used for heated air sensitive membrane, and each fan is used for the gas come out from gas sensitization film through overbaking to blow to air chamber bottom, are convenient to each sensor and detect; Horizontal baffle is used for partitioned air chambers upper and lower, thus facilitates air chamber upper and lower to carry out gas enrichment and sensor cleaning simultaneously; Bracing frame, guide frame, cross lead screw and the first motor move horizontally for driving horizontal baffle, thus make controller will be divided into upper and lower two parts by the first Electric Machine Control horizontal baffle in air chamber or make air chamber recover as a whole; Supporting plate provides support to track, and track provides the guiding moving to supporting plate different parts to detection head, and MQ-2 sensor and MQ-135 sensor are respectively used to testing environment signal, and methanol sensor is for detecting methanol gas signal; Second motor is for driving detection head along rail moving.

Because sensor all has cross sensitivity to detected object gas, therefore the present invention adopts MQ-2 sensor and MQ-135 sensor as aiding sensors, methanol sensor is as the master reference detecting methanol gas, the signal that MQ-2 sensor, MQ-135 sensor and methanol sensor detect is merged, obtain sensor fusion signal signal (t), thus both remained the Detection Information of master reference, remain again the signal difference information between master reference and aiding sensors, improve accuracy of detection.

Therefore, the present invention there is highly sensitive, good stability and the response time short, to methyl alcohol, there is good selectivity, the Trace Methanol gas that concentration is lower can be detected, thus effectively ensure the feature that people are healthy.

As preferably, described track comprises substrate, is located at two spaced grooves of upper surface of base plate, and described groove floor is provided with the tooth bar arranged at equal intervals; Be provided with bottom described detection head two with the gear of fit depressions; The rotating shaft of described second motor is connected with the coupling shaft be located between two gears.

As preferably, described substrate is provided with the first baffle plate, the second baffle relative with the first baffle plate; First baffle plate, second baffle are provided with corresponding guide chute; The coupling shaft two ends of described gear are provided with the outrigger shaft of guide chute for inserting the first baffle plate, second baffle; Detection head lower surface is provided with several balls with the first baffle plate, second baffle upper surface Structure deformation.The setting of guide chute, outrigger shaft and ball, make the stability of detection head better, friction force is less.

As preferably, support frame as described above comprises the U-shaped frame that Open Side Down, is located at the L shape frame of air chamber front and rear; Described guide frame is be located at two crossbeams between U-shaped frame and two L shape framves; Described web joint is rectangular, and web joint bottom is provided with for 2 through holes through two crossbeams, and web joint top is provided with the screw hole for coordinating with cross lead screw.

As preferably, in gas sensitization film, be provided with the cavity that several are spaced apart, in cavity, be provided with the carbon nano-tube of stretching out outside gas sensitization film upper and lower surface.Cavity and carbon nano-tube add the adsorptive power of gas sensitization film to gas.

To volatilize in laboratory environment the control method of methanol detection device, comprise the steps:

(6-1) solenoid valve that controller controls on the draft tube of air chamber bottom and escape pipe is all opened, in air chamber bottom, pure air is filled with by draft tube, to MQ-2 sensor, MQ-135 sensor and methanol sensor cleaning 6 to 20 minutes, after cleaning, the solenoid valve that controller controls on the draft tube of air chamber bottom and escape pipe all cuts out;

(6-2) solenoid valve that controller controls on the draft tube on air chamber top and escape pipe is opened, laboratory air to be detected is filled with to air chamber Inner eycle by draft tube, each gas sensitization film adsorbed gas, after 10 to 20 minutes, controller controls the closed electromagnetic valve on the draft tube on air chamber top and escape pipe;

(6-3) controller controls the first driven by motor cross lead screw and rotates, and cross lead screw drives horizontal baffle to move horizontally outside air chamber by web joint, and when horizontal baffle the inner being moved to contact with opening position, controller controls the first motor and quits work;

(6-4) controller controls the first wire netting and the energising of the second wire netting, control each electric fan work, the gas of gas sensitization film absorption enters air chamber bottom, after 5 to 10 minutes simultaneously, controller controls the first wire netting and the second wire netting power-off, and each electric fan quits work;

(6-5) controller controls the first driven by motor cross lead screw rotation, cross lead screw drives horizontal baffle to move horizontally in air chamber by web joint, when horizontal baffle outer end being moved to contact with opening position to contact, controller controls the first motor and quits work;

(6-6) controller passes through the second driven by motor detection head along rail moving, MQ-2 sensor, MQ-135 sensor and methanol sensor detect gas signal, controller receives detection signal S1 (t) of methanol sensor, detection signal S2 (t) of MQ-2 sensor, detection signal S3 (t) of MQ-135 sensor; Controller utilizes formula signal (t)=S1 ²(t)+(S1 (t)-S2 (t)) ²+ (S1 (t)-S3 (t)) ²calculating sensor merges signal signal (t);

(6-7) be previously stored with accidental resonance model and methanol concentration forecast model in storer, inputted by signal (t) in accidental resonance model, controller calculates the output signal-to-noise ratio SNR during resonance of accidental resonance model,

SNR is inputted in methanol concentration forecast model, obtain the methanol concentration of the laboratory air be detected.

Because sensor all has cross sensitivity to detected object gas, therefore the present invention adopts MQ-2 sensor and MQ-135 sensor as aiding sensors, methanol sensor is as the master reference detecting methanol gas, detection signal S1 (t) of methanol sensor, detection signal S2 (t) of MQ-2 sensor, detection signal S3 (t) of MQ-135 sensor, the present invention utilizes formula

Signal (t)=S1 ²(t)+(S1 (t)-S2 (t)) ²+ (S1 (t)-S3 (t)) ²the signal that MQ-2 sensor, MQ-135 sensor and methanol sensor detect is merged, obtain sensor fusion signal signal (t), thus both remained the Detection Information of master reference, remain again the signal difference information between master reference and aiding sensors, improve accuracy of detection.

As preferably, described step (6-1) is replaced by following step:

(7-1) solenoid valve that controller controls on the draft tube of air chamber bottom and escape pipe was all opened, and is filled with pure air by draft tube in air chamber bottom, to MQ-2 sensor, MQ-135 sensor and methanol sensor cleaning 5 to 10 minutes;

(7-2) be filled with to air chamber bottom the laboratory air that known methanol concentration is S by draft tube, ventilate after 3 to 10 minutes, the solenoid valve that controller controls on the draft tube of air chamber bottom and escape pipe all cuts out;

Controller passes through the second driven by motor detection head along rail moving, MQ-2 sensor, MQ-135 sensor and methanol sensor detect gas signal, controller receives detection signal S1 (t) of methanol sensor, detection signal S2 (t) of MQ-2 sensor, detection signal S3 (t) of MQ-135 sensor;

(7-3) n the sample value S11 be spacedly distributed of S1 (t) chosen by controller, S12 ..., S1n, choose n the sample value S21 be spacedly distributed of S2 (t), S22 ..., S2n, choose n the sample value S31 be spacedly distributed of S3 (t), S32 ..., S3n;

Utilize formula

Di ²=(S1i-S) ²+ (S2i-S) ²+ (S3i-S) ², i=1,2 ..., n, calculated difference distance di ²;

Utilize following formula $A=\left[\begin{array}{c}{(S11-S)}^2\\ {(S12-S)}^2\\ .\\ .\\ .\\ {(S1n-S)}^2\end{array}\right],B=\left[\begin{array}{c}{(S21-S)}^2\\ {(S22-S)}^2\\ .\\ .\\ .\\ {(S2n-S)}^2\end{array}\right],C=\left[\begin{array}{c}{(S31-S)}^2\\ {(S32-S)}^2\\ .\\ .\\ .\\ {(S3n-S)}^2\end{array}\right],$ $D=\left[\begin{array}{c}d{1}^2\\ d{2}^2\\ .\\ .\\ .\\ {\mathrm{dn}}^2\end{array}\right]$ Compute matrix A respectively, B, C and D; Minimum threshold e is provided with in storer;

(7-4) when data in A have 85%≤e at least and in D, data have 85%≤e at least, step (6-2) is proceeded to; Otherwise, proceed to step (7-1).

Step (7-2) to (7-4) is the trimming process to MQ-2 sensor, MQ-135 sensor and methanol sensor, only have and meet data in A and have 80%≤e at least and in D, data have the MQ-2 sensor of the correcting condition of 80%≤e, MQ-135 sensor and methanol sensor at least just for detecting gas to be detected, otherwise need repetition trimming process, thus improve the precision of sensor detection.

As preferably, the computation process of described output signal-to-noise ratio SNR comprises the steps:

Signal (t) is inputted one deck accidental resonance model

in;

Wherein, V (x, t, α) is potential function, the movement locus that x (t) is Brownian Particles, and t is run duration, and α is particle transient motion acceleration, D ₂for external noise intensity, N (t) grasps noise in being, for periodic sinusoidal signal, A ₁be signal amplitude, f is signal frequency, for phase place; A, b are the constant of setting; If

Controller calculates the first order derivative of V (x, t, α) for x, second derivative and three order derivatives, and makes equation equal 0, obtains two layers of accidental resonance model:

Setting noise intensity D ₂=0, signal (t)=0, N (t)=0; Calculate A ₁critical value be

By A ₁critical value substitute in one deck accidental resonance model, and set X ₀(t)=0, sn ₀=0, with quadravalence jade for asking rain Ge Kuta Algorithm for Solving one deck accidental resonance model, obtain

$x_{m1}\left(t\right)=x_m\left(t\right)+1/6\[{\left(k_1\right)}_m+(2-\sqrt{2}){\left(k_2\right)}_m+(2+\sqrt{2}){\left(k_3\right)}_m+{\left(k_4\right)}_m\],$

M=0,1 ..., N-1; And calculate:

(k ₁) _m＝4(aαx _m-1(t) ²-bαx _m-1(t) ³+sn _m-1(t))

${\left(k_2\right)}_m=4\[a\left({\mathrm{\αx}}_{m-1}\left(t\right)+\frac{{\left(k_1\right)}_{m-1}}{3}\right)-b{\left({\mathrm{\αx}}_{m-1}\left(t\right)+\frac{{\left(k_1\right)}_{m-1}}{3}\right)}^3+{\mathrm{sn}}_{m-1}\]$

${\left(k_3\right)}_m=4\[a\left({\mathrm{\αx}}_{m-1}\left(t\right)+\frac{{\left(k_2\right)}_{m-1}}{3}\right)-b{\left({\mathrm{\αx}}_{m-1}\left(t\right)+\frac{\sqrt{2}-1}{3}{\left(k_1\right)}_{m-1}+\frac{2-\sqrt{2}}{3}{\left(k_2\right)}_{m-1}\right)}^3+{\mathrm{sn}}_{m+1}\]$

${\left(k_4\right)}_n=4\[a\left(3{\mathrm{\αx}}_{m-1}\left(t\right)+{\left(k_3\right)}_{m-1}\right)-b{\left({\mathrm{\αx}}_{m-1}\left(t\right)-\frac{\sqrt{2}}{3}{\left(k_2\right)}_{m-1}+\frac{2+\sqrt{2}}{3}{\left(k_3\right)}_{m-1}\right)}^3+{\mathrm{sn}}_{m+1}\]$

Wherein, x _mt m order derivative that () is x (t), sn _m-1the value of m-1 order derivative at t=0 place of S (t), sn _m+1the m+1 order derivative being S (t), in the value at t=0 place, obtains x ₁(t), x ₂(t) ..., x _m+1the value of (t);

Controller is to x ₁(t), x ₂(t) ..., x _m+1t () carries out integration, obtain x (t), and obtains x (t) produces accidental resonance moment position x in the double-deck stochastic system of one deck accidental resonance model and two layers of accidental resonance model composition ₁value and x ₁corresponding resonance moment t ₁, optimum transient motion acceleration alpha ₁, and and t ₁and α ₁corresponding noise D ₁, D ₁for D ₂in a value; D ₂with a function of 0.01 loop cycle stepping in [0,1] scope, D ₂value and time correlation, be aware of t ₁moment, D ₁just determine.

Controller utilizes formula $SNR=2{\left({\mathrm{\ΔU}}^2\frac{4a^3/27b}{D_1}\right)}^3{e}^{-{\left(\mathrm{\Δ}U\right)}^3/D_1^2}$ Calculate the signal to noise ratio snr that double-deck stochastic resonance system exports; Wherein, Δ U=a ²/ 4b.

As preferably, controller calculates and obtains the averaged amplitude value SS of signal (t) in testing process, described A ₁≤ 0.48SS, the 11SS≤D in one deck accidental resonance model and two layers of accidental resonance model ₂≤ 19SS; A and b all≤0.91SS.

To A ₁, D ₂with the restriction of a and b span, guarantee that one deck accidental resonance model and two layers of accidental resonance model have good sensitivity, thus make the signal to noise ratio snr of output more accurate.

As preferably, methanol concentration forecast model is methanol concentration W=3.74+0.1068 × SNR.

Therefore, the present invention has following beneficial effect: (1) is highly sensitive, good stability and the response time short, to methyl alcohol, there is good selectivity, the Trace Methanol gas that concentration is lower can be detected, thus effective ensure that people are healthy; (2) simple to operate, testing cost is low.

Accompanying drawing explanation

Fig. 1 is a kind of theory diagram of the present invention;

Fig. 2 is a kind of cut-open view of air chamber of the present invention;

Fig. 3 is a kind of vertical view of methanol concentration pick-up unit of the present invention;

Fig. 4 is a kind of structural representation of web joint of the present invention;

Fig. 5 is a kind of cross-sectional structure schematic diagram of track of the present invention;

Fig. 6 is a kind of vertical view of track of the present invention;

Fig. 7 is a kind of process flow diagram of embodiments of the invention.

In figure: controller 1, base plate 2, air chamber 3, bracing frame 4, guide frame 5, cross lead screw 6, fan 7, gas sensitization film 8, second wire netting 9, horizontal baffle 10, supporting plate 11, track 12, detection head 13, first motor 14, web joint 15, second motor 16, solenoid valve 17, first wire netting 18, MQ-2 sensor 20, MQ-135 sensor 21, methanol sensor 22, draft tube 23, escape pipe 24, storer 25, substrate 121, groove 122, gear 123, coupling shaft 124, first baffle plate 125, second baffle 126, guide chute 127, outrigger shaft 128, U-shaped frame 41, L shape frame 42, crossbeam 51, through hole 151, screw hole 152, ball 129.

Embodiment

Below in conjunction with the drawings and specific embodiments, the present invention will be further described.

Embodiment 1

Embodiment is as shown in Figure 1 and Figure 2 the methanol detection device that volatilizees in a kind of laboratory environment, comprise controller 1, storer 25, base plate 2, be located at the rectangular air chamber 3 of xsect on base plate and bracing frame 4, be located at the guide frame 5 on bracing frame and cross lead screw 6;

As shown in Figure 2, air chamber inwall top is provided with for 5 fans 7 to canyon, the first wire netting 18 and the second wire netting 9 be made up of heating wire is provided with in air chamber top, the gas sensitization film 8 of 5 block gap distributions is provided with between first wire netting and the second wire netting, be provided with for air chamber being divided into upper and lower two-part horizontal baffle 10 in the air chamber of the second wire netting bottom, air chamber inner bottom part is provided with supporting plate 11, detection head 13 and the track 12 along splint upper surface Spiral distribution, and detection head is provided with MQ-2 sensor 20, MQ-135 sensor 21 and methanol sensor 22;

As shown in Figure 3, cross lead screw one end is connected with the rotating shaft of the first motor 14 be located on bracing frame, air chamber is provided with the opening for inserting horizontal baffle, horizontal baffle outer end is provided with web joint 15, detection head bottom is provided with the second motor 16 for driving detection head orbital motion, web joint is connected with wire rod thread, and web joint and guide frame are slidably connected, and the air chamber being positioned at horizontal baffle upper and lower is respectively equipped with one group of draft tube 23 and escape pipe 24; Draft tube and escape pipe are equipped with solenoid valve 17; Hermetically-sealed construction is provided with between opening and horizontal baffle;

As shown in Figure 1, controller is electrically connected with storer, each electric fan, each solenoid valve, the first wire netting, the second wire netting, the first motor, the second motor, MQ-2 sensor, MQ-135 sensor and methanol sensor respectively.

As shown in Figure 5, Figure 6, track comprises substrate 121, is located at two of upper surface of base plate spaced grooves 122, and groove floor is provided with the tooth bar arranged at equal intervals; Be provided with bottom detection head two with the gear 123 of fit depressions; The rotating shaft of the second motor is connected with the coupling shaft 124 be located between two gears.

Substrate is provided with the first baffle plate 125, the second baffle 126 relative with the first baffle plate; First baffle plate, second baffle are provided with corresponding guide chute 127; The coupling shaft two ends of gear are provided with the outrigger shaft 128 of guide chute for inserting the first baffle plate, second baffle; Detection head lower surface is provided with the multiple balls 129 with the first baffle plate, second baffle upper surface Structure deformation.

As shown in Figure 3, bracing frame comprises the U-shaped frame 41 that Open Side Down, is located at the L shape frame 42 of air chamber front and rear; Guide frame is be located at two crossbeams 51 between U-shaped frame and two L shape framves; As shown in Figure 4, web joint is rectangular, and web joint bottom is provided with for 2 through holes 151 through two crossbeams, and web joint top is provided with the screw hole 152 for coordinating with cross lead screw.

Be provided with multiple cavity spaced apart in gas sensitization film, in cavity, be provided with the carbon nano-tube of stretching out outside gas sensitization film upper and lower surface.

As shown in Figure 7, the control method of the methanol detection device that volatilizees in a kind of laboratory environment, comprises the steps:

Step 100, sensor cleans

The solenoid valve that controller controls on the draft tube of air chamber bottom and escape pipe is all opened, in air chamber bottom, pure air is filled with by draft tube, 20 minutes are cleaned to MQ-2 sensor, MQ-135 sensor and methanol sensor, after cleaning, the solenoid valve that controller controls on the draft tube of air chamber bottom and escape pipe all cuts out;

Step 200, the adsorbed gas of gas sensitization film

The solenoid valve that controller controls on the draft tube on air chamber top and escape pipe is opened, laboratory air to be detected is filled with to air chamber Inner eycle by draft tube, each gas sensitization film adsorbed gas, after 20 minutes, controller controls the closed electromagnetic valve on the draft tube on air chamber top and escape pipe;

Step 300, takes out boiling water flat partition board

Controller controls the first driven by motor cross lead screw and rotates, and cross lead screw drives horizontal baffle to move horizontally outside air chamber by web joint, and when horizontal baffle the inner being moved to contact with opening position, controller controls the first motor and quits work;

Step 400, heated air sensitive membrane, and the gas that gas sensitization film discharges is blowed to air chamber bottom

Controller controls the first wire netting and the energising of the second wire netting, controls each electric fan work simultaneously, and the gas of gas sensitization film absorption enters air chamber bottom, and after 5 to 10 minutes, controller controls the first wire netting and the second wire netting power-off, and each electric fan quits work;

Step 500, closed horizontal baffle

Controller controls the first driven by motor cross lead screw and rotates, and cross lead screw drives horizontal baffle to move horizontally in air chamber by web joint, and when horizontal baffle outer end being moved to contact with opening position to contact, controller controls the first motor and quits work;

Step 600, each sensor detects gas signal and obtains sensor fusion signal

Controller passes through the second driven by motor detection head along rail moving, MQ-2 sensor, MQ-135 sensor and methanol sensor detect gas signal, controller receives detection signal S1 (t) of methanol sensor, detection signal S2 (t) of MQ-2 sensor, detection signal S3 (t) of MQ-135 sensor; Controller utilizes formula signal (t)=S1 ²(t)+(S1 (t)-S2 (t)) ²+ (S1 (t)-S3 (t)) ²calculating sensor merges signal signal (t);

Step 700, calculates and obtains the methanol concentration of laboratory air that detects

Be previously stored with accidental resonance model and methanol concentration forecast model in storer, inputted by signal (t) in accidental resonance model, controller calculates the output signal-to-noise ratio SNR during resonance of accidental resonance model,

SNR is inputted methanol concentration forecast model: in methanol concentration W=3.74+0.1068 × SNR, obtain the methanol concentration of the laboratory air be detected.

Methanol concentration forecast model utilizes step 100 to detect various concentration known to 700 to be respectively W1, W2 ..., the methanol gas of W100, obtains the output signal-to-noise ratio SNR1 corresponding with often kind of methanol concentration, SNR2 ..., SNR100; Utilize point (W1, SNR1), (W2, SNR2),, (W100, SNR100) does a little in rectangular coordinate system, obtain the formula of the matched curve of each point, the formula of matched curve is converted, obtains methanol concentration forecast model of the present invention.

The computation process of described output signal-to-noise ratio SNR comprises the steps:

Signal (t) is inputted one deck accidental resonance model

in;

Wherein, V (x, t, α) is potential function, the movement locus that x (t) is Brownian Particles, and t is run duration, and α is particle transient motion acceleration, D ₂for external noise intensity, N (t) grasps noise in being, for periodic sinusoidal signal, A ₁be signal amplitude, f is signal frequency, for phase place; A, b are the constant of setting; If controller calculates and obtains the averaged amplitude value SS of signal (t) in testing process, A ₁≤ 0.5SS, the 10SS≤D in one deck accidental resonance model and two layers of accidental resonance model ₂≤ 20SS; A and b all≤SS.

Controller calculates the first order derivative of V (x, t, α) for x, second derivative and three order derivatives, and makes equation equal 0, obtains two layers of accidental resonance model:

Setting noise intensity D ₂=0, signal (t)=0, N (t)=0; Calculate A ₁critical value be

By A ₁critical value substitute in one deck accidental resonance model, and set X ₀(t)=0, sn ₀=0, with quadravalence jade for asking rain Ge Kuta Algorithm for Solving one deck accidental resonance model, obtain

$x_{m1}\left(t\right)=x_m\left(t\right)+1/6\[{\left(k_1\right)}_m+(2-\sqrt{2}){\left(k_2\right)}_m+(2+\sqrt{2}){\left(k_3\right)}_m+{\left(k_4\right)}_m\],$

M=0,1 ..., N-1; And calculate:

(k ₁) _m＝4(aαx _m-1(t) ²-bαx _m-1(t) ³+sn _m-1(t))

${\left(k_2\right)}_m=4\[a\left({\mathrm{\αx}}_{m-1}\left(t\right)+\frac{{\left(k_1\right)}_{m-1}}{3}\right)-b{\left({\mathrm{\αx}}_{m-1}\left(t\right)+\frac{{\left(k_1\right)}_{m-1}}{3}\right)}^3+{\mathrm{sn}}_{m-1}\]$

${\left(k_3\right)}_m=4\[a\left({\mathrm{\αx}}_{m-1}\left(t\right)+\frac{{\left(k_2\right)}_{m-1}}{3}\right)-b{\left({\mathrm{\αx}}_{m-1}\left(t\right)+\frac{\sqrt{2}-1}{3}{\left(k_1\right)}_{m-1}+\frac{2-\sqrt{2}}{3}{\left(k_2\right)}_{m-1}\right)}^3+{\mathrm{sn}}_{m+1}\]$

${\left(k_4\right)}_n=4\[a\left(3{\mathrm{\αx}}_{m-1}\left(t\right)+{\left(k_3\right)}_{m-1}\right)-b{\left({\mathrm{\αx}}_{m-1}\left(t\right)-\frac{\sqrt{2}}{3}{\left(k_2\right)}_{m-1}+\frac{2+\sqrt{2}}{3}{\left(k_3\right)}_{m-1}\right)}^3+{\mathrm{sn}}_{m+1}\]$

Wherein, x _mt m order derivative that () is x (t), sn _m-1the value of m-1 order derivative at t=0 place of S (t), sn _m+1the m+1 order derivative being S (t), in the value at t=0 place, obtains x ₁(t), x ₂(t) ..., x _m+1the value of (t);

Controller is to x ₁(t), x ₂(t) ..., x _m+1t () carries out integration, obtain x (t), and obtains x (t) produces accidental resonance moment position x in the double-deck stochastic system of one deck accidental resonance model and two layers of accidental resonance model composition ₁value and x ₁corresponding resonance moment t ₁, optimum transient motion acceleration alpha ₁, and and t ₁and α ₁corresponding noise D ₁, D ₁for D ₂in a value;

Controller utilizes formula $SNR=2{\left({\mathrm{\ΔU}}^2\frac{4a^3/27b}{D_1}\right)}^3{e}^{-{\left(\mathrm{\Δ}U\right)}^3/D_1^2}$ Calculate the signal to noise ratio snr that double-deck stochastic resonance system exports; Wherein, Δ U=a ²/ 4b.

Embodiment 2

Embodiment 2 comprises all structures in embodiment 1 and step part, the step 100 of embodiment 2 in following steps alternative embodiment 1:

Step 110, sensor cleans

The solenoid valve that controller controls on the draft tube of air chamber bottom and escape pipe is all opened, and is filled with pure air, cleans 10 minutes to MQ-2 sensor, MQ-135 sensor and methanol sensor by draft tube in air chamber bottom;

Step 120, sensor calibration

Be filled with to air chamber bottom the laboratory air that known methanol concentration is S by draft tube, duration of ventilation is 200 seconds, and the solenoid valve that controller controls on the draft tube of air chamber bottom and escape pipe all cuts out;

Controller passes through the second driven by motor detection head along rail moving, MQ-2 sensor, MQ-135 sensor and methanol sensor detect gas signal, controller receives detection signal S1 (t) of methanol sensor, detection signal S2 (t) of MQ-2 sensor, detection signal S3 (t) of MQ-135 sensor;

Step 130, n=20 the sample value S11 be spacedly distributed of S1 (t) chosen by controller, S12, ..., S1n, chooses n the sample value S21 be spacedly distributed of S2 (t), S22, ..., S2n, chooses n the sample value S31 be spacedly distributed of S3 (t), S32, ..., S3n;

Utilize formula

Di ²=(S1i-S) ²+ (S2i-S) ²+ (S3i-S) ², i=1,2 ..., n, calculated difference distance di ²;

Utilize following formula $A=\left[\begin{array}{c}{(S11-S)}^2\\ {(S12-S)}^2\\ .\\ .\\ .\\ {(S1n-S)}^2\end{array}\right],B=\left[\begin{array}{c}{(S21-S)}^2\\ {(S22-S)}^2\\ .\\ .\\ .\\ {(S2n-S)}^2\end{array}\right],C=\left[\begin{array}{c}{(S31-S)}^2\\ {(S32-S)}^2\\ .\\ .\\ .\\ {(S3n-S)}^2\end{array}\right],$ $D=\left[\begin{array}{c}d{1}^2\\ d{2}^2\\ .\\ .\\ .\\ {\mathrm{dn}}^2\end{array}\right]$ Compute matrix A respectively, B, C and D; Minimum threshold e is provided with in storer;

Step 140, as A+B+C=D and in A every item number according to have 80%≤e at least and in D, every item number certificate has 80%≤e at least time, proceed to step 200; Otherwise, proceed to step 110.

Should be understood that the present embodiment is only not used in for illustration of the present invention to limit the scope of the invention.In addition should be understood that those skilled in the art can make various changes or modifications the present invention, and these equivalent form of values fall within the application's appended claims limited range equally after the content of having read the present invention's instruction.

Claims (10)

1. volatilize in a laboratory environment methanol detection device, it is characterized in that, comprise controller (1), storer (25), base plate (2), be located at the rectangular air chamber (3) of xsect on base plate and bracing frame (4), be located at the guide frame (5) on bracing frame and cross lead screw (6);

Described air chamber inwall top is provided with for several fans (7) to canyon, the first wire netting (18) and the second wire netting (9) that are made up of heating wire is provided with in air chamber top, the gas sensitization film (8) of some block gaps distribution is provided with between first wire netting and the second wire netting, be provided with for air chamber being divided into upper and lower two-part horizontal baffle (10) in the air chamber of the second wire netting bottom, air chamber inner bottom part is provided with supporting plate (11), detection head (13) and the track (12) along splint upper surface Spiral distribution, detection head is provided with MQ-2 sensor (20), MQ-135 sensor (21) and methanol sensor (22),

Cross lead screw one end is connected with the rotating shaft of the first motor (14) be located on bracing frame, described air chamber is provided with the opening for inserting horizontal baffle, horizontal baffle outer end is provided with web joint (15), detection head bottom is provided with the second motor (16) for driving detection head orbital motion, web joint is connected with wire rod thread, web joint and guide frame are slidably connected, and the air chamber being positioned at horizontal baffle upper and lower is respectively equipped with one group of draft tube (23) and escape pipe (24); Draft tube and escape pipe are equipped with solenoid valve (17); Hermetically-sealed construction is provided with between opening and horizontal baffle;

Controller is electrically connected with storer, each electric fan, each solenoid valve, the first wire netting, the second wire netting, the first motor, the second motor, MQ-2 sensor, MQ-135 sensor and methanol sensor respectively.

2. volatilize in laboratory environment according to claim 1 methanol detection device, it is characterized in that, described track comprises substrate (121), is located at two spaced grooves (122) of upper surface of base plate, and described groove floor is provided with the tooth bar arranged at equal intervals; Be provided with bottom described detection head two with the gear (123) of fit depressions; The rotating shaft of described second motor is connected with the coupling shaft be located between two gears (124).

3. volatilize in laboratory environment according to claim 2 methanol detection device, and it is characterized in that, described substrate is provided with the first baffle plate (125), the second baffle (126) relative with the first baffle plate; First baffle plate, second baffle are provided with corresponding guide chute (127); The coupling shaft two ends of described gear are provided with the outrigger shaft (128) of guide chute for inserting the first baffle plate, second baffle; Detection head lower surface is provided with several balls (129) with the first baffle plate, second baffle upper surface Structure deformation.

4. volatilize in laboratory environment according to claim 1 methanol detection device, it is characterized in that, support frame as described above comprises the U-shaped frame (41) that Open Side Down, is located at the L shape frame (42) of air chamber front and rear; Described guide frame is two crossbeams (51) be located between U-shaped frame and two L shape framves; Described web joint is rectangular, and web joint bottom is provided with for 2 through holes (151) through two crossbeams, and web joint top is provided with the screw hole (152) for coordinating with cross lead screw.

5. volatilize in the laboratory environment according to claim 1 or 2 or 3 or 4 or 5 methanol detection device, it is characterized in that, be provided with the cavity that several are spaced apart in gas sensitization film, be provided with the carbon nano-tube of stretching out outside gas sensitization film upper and lower surface in cavity.

6. to volatilize in laboratory environment according to claim 1 the control method of methanol detection device, it is characterized in that, comprise the steps:

(6-1) solenoid valve that controller controls on the draft tube of air chamber bottom and escape pipe is all opened, in air chamber bottom, pure air is filled with by draft tube, to MQ-2 sensor, MQ-135 sensor and methanol sensor cleaning 6 to 20 minutes, after cleaning, the solenoid valve that controller controls on the draft tube of air chamber bottom and escape pipe all cuts out;

(6-2) solenoid valve that controller controls on the draft tube on air chamber top and escape pipe is opened, laboratory air to be detected is filled with to air chamber Inner eycle by draft tube, each gas sensitization film adsorbed gas, after 10 to 20 minutes, controller controls the closed electromagnetic valve on the draft tube on air chamber top and escape pipe;

(6-3) controller controls the first driven by motor cross lead screw and rotates, and cross lead screw drives horizontal baffle to move horizontally outside air chamber by web joint, and when horizontal baffle the inner being moved to contact with opening position, controller controls the first motor and quits work;

(6-4) controller controls the first wire netting and the energising of the second wire netting, control each electric fan work, the gas of gas sensitization film absorption enters air chamber bottom, after 5 to 10 minutes simultaneously, controller controls the first wire netting and the second wire netting power-off, and each electric fan quits work;

(6-5) controller controls the first driven by motor cross lead screw rotation, cross lead screw drives horizontal baffle to move horizontally in air chamber by web joint, when horizontal baffle outer end being moved to contact with opening position to contact, controller controls the first motor and quits work;

(6-6) controller passes through the second driven by motor detection head along rail moving, MQ-2 sensor, MQ-135 sensor and methanol sensor detect gas signal, controller receives detection signal S1 (t) of methanol sensor, detection signal S2 (t) of MQ-2 sensor, detection signal S3 (t) of MQ-135 sensor; Controller utilizes formula signal (t)=S1 ²(t)+(S1 (t)-S2 (t)) ²+ (S1 (t)-S3 (t)) ²calculating sensor merges signal signal (t);

(6-7) be previously stored with accidental resonance model and methanol concentration forecast model in storer, inputted by signal (t) in accidental resonance model, controller calculates the output signal-to-noise ratio SNR during resonance of accidental resonance model,

SNR is inputted in methanol concentration forecast model, obtain the methanol concentration of the laboratory air be detected.

7. volatilize in laboratory environment according to claim 1 the control method of methanol detection device, it is characterized in that, described step (6-1) is replaced by following step:

(7-1) solenoid valve that controller controls on the draft tube of air chamber bottom and escape pipe was all opened, and is filled with pure air by draft tube in air chamber bottom, to MQ-2 sensor, MQ-135 sensor and methanol sensor cleaning 5 to 10 minutes;

(7-2) be filled with to air chamber bottom the laboratory air that known methanol concentration is S by draft tube, ventilate after 3 to 10 minutes, the solenoid valve that controller controls on the draft tube of air chamber bottom and escape pipe all cuts out;

Controller passes through the second driven by motor detection head along rail moving, MQ-2 sensor, MQ-135 sensor and methanol sensor detect gas signal, controller receives detection signal S1 (t) of methanol sensor, detection signal S2 (t) of MQ-2 sensor, detection signal S3 (t) of MQ-135 sensor;

(7-3) n the sample value S11 be spacedly distributed of S1 (t) chosen by controller, S12 ..., S1n, choose n the sample value S21 be spacedly distributed of S2 (t), S22 ..., S2n, choose n the sample value S31 be spacedly distributed of S3 (t), S32 ..., S3n;

Utilize formula

Di ²=(S1i-S) ²+ (S2i-S) ²+ (S3i-S) ², i=1,2 ..., n, calculated difference distance di ²;

Utilize following formula $A=\left[\begin{array}{c}{(S11-S)}^2\\ {(S12-S)}^2\\ .\\ .\\ .\\ {(S1n-S)}^2\end{array}\right],B=\left[\begin{array}{c}{(S21-S)}^2\\ {(S22-S)}^2\\ .\\ .\\ .\\ {(S2n-S)}^2\end{array}\right],C=\left[\begin{array}{c}{(S31-S)}^2\\ {(S32-S)}^2\\ .\\ .\\ .\\ {(S3n-S)}^2\end{array}\right],$ $D=\left[\begin{array}{c}d{1}^2\\ d{2}^2\\ .\\ .\\ .\\ {\mathrm{dn}}^2\end{array}\right]$ Compute matrix A respectively, B, C and D; Minimum threshold e is provided with in storer;

(7-4) when data in A have 85%≤e at least and in D, data have 85%≤e at least, step (6-2) is proceeded to; Otherwise, proceed to step (7-1).

8. volatilize in laboratory environment according to claim 1 the control method of methanol detection device, it is characterized in that, the computation process of described output signal-to-noise ratio SNR comprises the steps:

Signal (t) is inputted one deck accidental resonance model

in;

Wherein, V (x, t, α) is potential function, the movement locus that x (t) is Brownian Particles, and t is run duration, and α is particle transient motion acceleration, D ₂for external noise intensity, N (t) grasps noise in being, for periodic sinusoidal signal, A ₁be signal amplitude, f is signal frequency, for phase place; A, b are the constant of setting; If

Controller calculates the first order derivative of V (x, t, α) for x, second derivative and three order derivatives, and makes equation equal 0, obtains two layers of accidental resonance model:

Setting noise intensity D ₂=0, signal (t)=0, N (t)=0; Calculate A ₁critical value be

By A ₁critical value substitute in one deck accidental resonance model, and set X ₀(t)=0, sn ₀=0, with quadravalence jade for asking rain Ge Kuta Algorithm for Solving one deck accidental resonance model, obtain

$x_{m1}\left(t\right)=x_m\left(t\right)+1/6\[{\left(k_1\right)}_m+(2-\sqrt{2}){\left(k_2\right)}_m+(2+\sqrt{2}){\left(k_3\right)}_m+{\left(k_4\right)}_m\],$

M=0,1 ..., N-1; And calculate:

(k ₁) _m＝4(aαx _m-1(t) ²-bαx _m-1(t) ³+sn _m-1(t))

${\left(k_2\right)}_m=4\[a\left({\mathrm{\αx}}_{m-1}\left(t\right)+\frac{{\left(k_1\right)}_{m-1}}{3}\right)-b{\left({\mathrm{\αx}}_{m-1}\left(t\right)+\frac{{\left(k_1\right)}_{m-1}}{3}\right)}^3+{\mathrm{sn}}_{m-1}\]$

${\left(k_3\right)}_m=4\[a\left({\mathrm{\αx}}_{m-1}\left(t\right)+\frac{{\left(k_2\right)}_{m-1}}{3}\right)-b{\left({\mathrm{\αx}}_{m-1}\left(t\right)+\frac{\sqrt{2}-1}{3}{\left(k_1\right)}_{m-1}+\frac{2-\sqrt{2}}{3}{\left(k_2\right)}_{m-1}\right)}^3+{\mathrm{sn}}_{m+1}\]$

${\left(k_4\right)}_n=4\[a\left(3{\mathrm{\αx}}_{m-1}\left(t\right)+{\left(k_3\right)}_{m-1}\right)-b{\left({\mathrm{\αx}}_{m-1}\left(t\right)-\frac{\sqrt{2}}{3}{\left(k_2\right)}_{m-1}+\frac{2+\sqrt{2}}{3}{\left(k_3\right)}_{m-1}\right)}^3+{\mathrm{sn}}_{m+1}\]$

Wherein, x _mt m order derivative that () is x (t), sn _m-1the value of m-1 order derivative at t=0 place of S (t), sn _m+1the m+1 order derivative being S (t), in the value at t=0 place, obtains x ₁(t), x ₂(t) ..., x _m+1the value of (t);

Controller is to x ₁(t), x ₂(t) ..., x _m+1t () carries out integration, obtain x (t), and obtains x (t) produces accidental resonance moment position x in the double-deck stochastic system of one deck accidental resonance model and two layers of accidental resonance model composition ₁value and x ₁corresponding resonance moment t ₁, optimum transient motion acceleration alpha ₁, and and t ₁and α ₁corresponding noise D ₁, D ₁for D ₂in a value;

Controller utilizes formula $SNR=2{\left({\mathrm{\ΔU}}^2\frac{4a^3/27b}{D_1}\right)}^3{e}^{-{\left(\mathrm{\Δ}U\right)}^3/D_1^2}$ Calculate the signal to noise ratio snr that double-deck stochastic resonance system exports; Wherein, Δ U=a ²/ 4b.

9. volatilize in laboratory environment according to claim 8 the control method of methanol detection device, it is characterized in that, controller calculates and obtains the averaged amplitude value SS of signal (t) in testing process, described A ₁≤ 0.48SS, the 11SS≤D in one deck accidental resonance model and two layers of accidental resonance model ₂≤ 19SS; A and b all≤0.91SS.

10. volatilize in the laboratory environment according to claim 6 or 7 or 8 or 9 control method of methanol detection device, it is characterized in that, methanol concentration forecast model is methanol concentration W=3.74+0.1068 × SNR.