CN216978819U - Water quality chemical oxygen demand online analyzer - Google Patents
Water quality chemical oxygen demand online analyzer Download PDFInfo
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- CN216978819U CN216978819U CN202220153124.3U CN202220153124U CN216978819U CN 216978819 U CN216978819 U CN 216978819U CN 202220153124 U CN202220153124 U CN 202220153124U CN 216978819 U CN216978819 U CN 216978819U
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- peristaltic pump
- metering
- reagent
- oxygen demand
- chemical oxygen
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 96
- 239000000126 substance Substances 0.000 title claims abstract description 39
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 title claims abstract description 34
- 239000001301 oxygen Substances 0.000 title claims abstract description 34
- 229910052760 oxygen Inorganic materials 0.000 title claims abstract description 34
- 230000002572 peristaltic effect Effects 0.000 claims abstract description 90
- 230000029087 digestion Effects 0.000 claims abstract description 79
- 239000003153 chemical reaction reagent Substances 0.000 claims abstract description 70
- 238000001514 detection method Methods 0.000 claims abstract description 40
- 238000006243 chemical reaction Methods 0.000 claims abstract description 29
- 239000012153 distilled water Substances 0.000 claims abstract description 26
- 238000005070 sampling Methods 0.000 claims abstract description 4
- 239000007788 liquid Substances 0.000 claims description 35
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 21
- 239000010453 quartz Substances 0.000 claims description 20
- 238000010438 heat treatment Methods 0.000 claims description 18
- 230000003647 oxidation Effects 0.000 claims description 5
- 238000007254 oxidation reaction Methods 0.000 claims description 5
- 230000007797 corrosion Effects 0.000 claims description 3
- 238000005260 corrosion Methods 0.000 claims description 3
- 239000007789 gas Substances 0.000 claims description 3
- 230000003287 optical effect Effects 0.000 claims description 3
- 238000002156 mixing Methods 0.000 abstract description 2
- 239000012295 chemical reaction liquid Substances 0.000 description 9
- 239000002699 waste material Substances 0.000 description 9
- 238000005259 measurement Methods 0.000 description 8
- 238000011084 recovery Methods 0.000 description 7
- 239000008237 rinsing water Substances 0.000 description 6
- 238000011088 calibration curve Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 238000012544 monitoring process Methods 0.000 description 5
- 238000002835 absorbance Methods 0.000 description 4
- 238000004140 cleaning Methods 0.000 description 4
- KMUONIBRACKNSN-UHFFFAOYSA-N potassium dichromate Chemical compound [K+].[K+].[O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O KMUONIBRACKNSN-UHFFFAOYSA-N 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000005086 pumping Methods 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 238000005406 washing Methods 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 238000005034 decoration Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000005611 electricity Effects 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- DOBUSJIVSSJEDA-UHFFFAOYSA-L 1,3-dioxa-2$l^{6}-thia-4-mercuracyclobutane 2,2-dioxide Chemical compound [Hg+2].[O-]S([O-])(=O)=O DOBUSJIVSSJEDA-UHFFFAOYSA-L 0.000 description 1
- AFCARXCZXQIEQB-UHFFFAOYSA-N N-[3-oxo-3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)propyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C(CCNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)N1CC2=C(CC1)NN=N2 AFCARXCZXQIEQB-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000007865 diluting Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000010842 industrial wastewater Substances 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 229910000370 mercury sulfate Inorganic materials 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000000741 silica gel Substances 0.000 description 1
- 229910002027 silica gel Inorganic materials 0.000 description 1
- 229910000367 silver sulfate Inorganic materials 0.000 description 1
- YPNVIBVEFVRZPJ-UHFFFAOYSA-L silver sulfate Chemical compound [Ag+].[Ag+].[O-]S([O-])(=O)=O YPNVIBVEFVRZPJ-UHFFFAOYSA-L 0.000 description 1
- 238000002798 spectrophotometry method Methods 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
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Abstract
The utility model provides a water quality chemical oxygen demand online analyzer, which comprises a plurality of peristaltic pumps, a plurality of pinch valves, a plurality of three-way joints, a reagent metering unit, a digestion reaction unit, a photoelectric detection unit and a single chip microcomputer; the reagent metering unit is connected to the digestion reaction unit through two reagent sample introduction channels, the digestion reaction unit is connected with the photoelectric detection unit through a detection channel, and the digestion reaction unit is also connected with a distilled water sample introduction channel and a water sample introduction channel; the singlechip is used for controlling each electronic component in the analyzer. The utility model can realize the complete detection steps of the chemical oxygen demand, such as sampling, metering, mixing, digestion, spectrophotometric detection and the like, and realize the automatic, rapid and accurate analysis of the chemical oxygen demand in water. The utility model has 5 sample introduction channels which can be automatically switched according to the needs at regular time, and the light source of the photoelectric detection component uses an LED light source, so that the safe voltage can be lightened, and the safety and the stability of the circuit are improved.
Description
Technical Field
The utility model belongs to the technical field of environmental monitoring, relates to a water quality online analyzer, and particularly relates to a water quality chemical oxygen demand online analyzer.
Background
Chemical Oxygen Demand (COD) is a Chemical method for measuring the amount of reducing substances to be oxidized in a water sample. In the research of river pollution and the property of industrial wastewater and the operation management of wastewater treatment plants, it is an important and relatively fast measurable organic pollution parameter, often denoted by the symbol COD. COD measurement, which is different with the measurement of reducing substances in a water sample and the measurement method; the potassium dichromate oxidation method has high oxidation rate and good reproducibility, and is suitable for determining the total amount of organic matters in a water sample.
The water quality chemical oxygen demand on-line analyzer has become a main means for continuously monitoring the water quality conditions in the district of environmental protection, water conservancy and other departments, can continuously, stably and reliably provide accurate and rapid monitoring data, and has large market demand. The domestic water quality detecting instrument starts late, and the current domestic chemical oxygen demand analyzer has various defects of long analysis time, large reagent consumption, high power consumption, low data accuracy, relatively high failure rate, frequent operation and maintenance, large size and the like.
Disclosure of Invention
Aiming at the defects of long analysis time, high detection cost, low stability and the like of the existing chemical oxygen demand online analysis instrument, the utility model provides the water quality chemical oxygen demand online analyzer which has the advantages of accurate measurement, high stability, less reagent consumption, relatively low detection cost and simple and convenient operation, and provides reliable guarantee for long-term and accurate monitoring of water quality chemical oxygen demand.
In order to achieve the purpose, the technical scheme of the utility model is as follows:
a water quality chemical oxygen demand on-line analyzer comprises a plurality of peristaltic pumps, a plurality of pinch valves, a plurality of three-way joints, a reagent metering unit, a digestion reaction unit, a photoelectric detection unit and a single chip microcomputer; the reagent metering unit is connected to the digestion reaction unit through two reagent sample introduction channels, the digestion reaction unit is connected with the photoelectric detection unit through a detection channel, and the digestion reaction unit is also connected with a distilled water sample introduction channel and a water sample introduction channel; the single chip microcomputer is used for controlling all electronic components in the analyzer;
the reagent metering unit comprises two groups of transparent quartz metering tubes, the lower ends of the two metering tubes are respectively connected with a pinch valve, the outer sides of the two pinch valves are respectively connected with a reagent bottle, and the inner sides of the two pinch valves are connected with the digestion reaction unit; the upper ends of the two metering pipes are connected with three-way electromagnetic air valves, and the three-way electromagnetic air valves are linearly connected in series and are connected with the first peristaltic pump; the side surfaces of the metering pipes are respectively provided with a liquid level meter at the upper part and the lower part, and the generated electric signals indirectly control the three-way electromagnetic air valve, the first pinch valve, the second pinch valve and the first peristaltic pump to operate through the singlechip;
the digestion reaction unit comprises a quartz digestion tank, the bottom of the digestion tank is provided with a sample inlet, the sample inlet is connected with a first two-way valve, and the upper part of the digestion tank is connected with a second two-way valve as a gas pressure balancing port; a heating wire is wrapped outside the whole digestion tank, and a temperature sensor is arranged on the side of the digestion tank; the single chip microcomputer collects data of the temperature sensor and controls the on-off of the heating wire; the first two-way valve is connected with one end of the second peristaltic pump, and the other end of the second peristaltic pump is connected with the third pinch valve;
the shell of the photoelectric detection component is an opaque rectangular box body, one side of the shell is provided with an LED light source, the other side of the shell is provided with a photocell, an optical lens is arranged between the shell and the photocell, a quartz cuvette is arranged at a position close to the photocell, and the lower opening of the cuvette is connected with the outer side of a third pinch valve; the single chip microcomputer controls the LED light source and collects the electric signal of the photocell;
the water sample sampling channel comprises a water sample reagent bottle and a fourth peristaltic pump, the water sample reagent bottle is connected with the fourth peristaltic pump through a pipeline, and the fourth peristaltic pump is connected to a first two-way valve of the digestion reaction unit;
the distilled water sample introduction channel comprises a distilled water reagent bottle and a third peristaltic pump, the distilled water reagent bottle is connected with the third peristaltic pump through a pipeline, and the third peristaltic pump is connected to a first two-way valve of the digestion reaction unit.
Furthermore, one of the two metering pipes is provided with an ellipsoidal cavity in the middle, and the two liquid level meters are respectively positioned at the upper end and the lower end of the ellipsoidal cavity; the lower end of the other metering tube is provided with an ellipsoidal cavity, and the two liquid level meters are both positioned above the ellipsoidal cavity.
Further, the inner side is opened and the outer side is closed when the pinch valve is powered on, the inner side is closed and the outer side is opened when the pinch valve is powered off, and the two-way valve is opened when the pinch valve is powered on and closed when the pinch valve is powered off.
Further, the two-way valve is a high pressure resistant and high temperature resistant two-way valve.
Further, the LED light source is a 470nmLED light source.
Furthermore, the sample introduction channel, the detection channel, the distilled water sample introduction channel and the water sample introduction channel are all formed by oxidation-resistant and corrosion-resistant hoses.
The utility model has the beneficial effects that:
1. the utility model realizes the automatic, rapid and accurate analysis of the chemical oxygen demand in water by fully automating the steps of sampling, metering, mixing, digesting, spectrophotometry detection and the like.
2. The utility model has 5 sample introduction channels, can be automatically switched according to the requirement at regular time, and the light source of the photoelectric detection component uses an LED light source, so that the safe voltage can be lightened, thereby improving the safety and the stability of the circuit.
3. The utility model realizes the full-automatic monitoring of the chemical oxygen demand of water quality, and has the advantages of less reagent consumption, short time consumption, low cost, accurate measurement, high stability, simple and convenient operation and the like, thereby having wide application prospect.
Drawings
FIG. 1 is a schematic structural diagram of an on-line analyzer for chemical oxygen demand of water quality provided by the present invention.
FIG. 2 is a block diagram of the connection of the electrical components of the water quality chemical oxygen demand on-line analyzer provided by the present invention.
List of reference symbols:
R1-R4: first to fourth peristaltic pumps, T1-T3: first to third pinch valves, J: three-way joint, S1-S2: first and second reagent bottles, S3: distilled water reagent bottle, S4: a water sample reagent bottle; each part in the reagent metering unit comprises: q: three-way electromagnetic gas valve, Y1-Y4: first to fourth photoelectric liquid level switches, a1-a 2: first and second quartz metering tubes; the components in the digestion reaction unit include: E1-E2: first and second two-way valves, F: digestion tank, H: heating wires; g: photodetection unit, G1: LED light source, G2: diode detector, G3: a colorimetric pool.
Detailed Description
The technical solutions provided by the present invention will be described in detail with reference to specific examples, which should be understood that the following specific embodiments are only illustrative and not limiting the scope of the present invention. The dimensions of various elements and structures in the drawings are not intended to represent actual dimensions, and the positional or positional relationships are based on the orientations shown in the drawings for simplicity of description only and are not intended to represent the particular orientations of the actual devices or elements; the terms "connect", "open" and the like are to be understood in a broad sense, e.g. "connect" may be a mechanical connection or a connection by a hose or an electrical connection, as the term is understood by those skilled in the art in the specific sense.
The utility model provides a water quality chemical oxygen demand on-line analyzer, as shown in figure 1, comprising: the device comprises a plurality of liquid conveying pipelines, a plurality of peristaltic pumps (R1-R4), a plurality of pinch valves (T1-T3), a plurality of three-way joints J, a reagent metering unit, a digestion reaction unit, a photoelectric detection unit, a single chip microcomputer and the like. Wherein, each liquid conveying pipeline is matched with a plurality of pinch valves (T1-T3), a plurality of tee joints J for connection and the work of different peristaltic pumps to form 5 sample introduction channels, a plurality of reagent sub-channels, a plurality of conveying sub-channels and a plurality of waste liquid sub-channels. The digestion reaction unit is connected with the reagent metering unit through the reagent sub-channel; the photoelectric detection assembly is connected with the digestion tank through the conveying sub-channel; waste liquid generated by each unit is uniformly discharged into the waste liquid recovery barrel through the waste liquid sub-channel, and cleaning water is uniformly discharged into the cleaning water recovery part through the waste liquid sub-channel. Electronic components in the peristaltic pump, the pinch valve, the reagent metering unit, the digestion reaction unit and the photoelectric detection unit are electrically connected with and controlled by the singlechip. The single-chip microcomputer is not depicted in fig. 1. The various liquid conveying channels are made of oxidation-resistant and corrosion-resistant hoses. In the utility model, one side of the pinch valve is opened and the other side is closed inevitably, the inner side of the pinch valve is opened and the outer side is closed when electricity is supplied, and the inner side is closed and the outer side is opened when electricity is cut off. In the initial state, all pumps are closed, and the left outer side of a pinch valve (T1-T3) is opened.
The reagent metering assembly comprises two groups of transparent quartz metering tubes which are respectively used for metering a reagent 1 and a reagent 2. The lower ends of the two metering pipes (A1, A2) are respectively connected with a first pinch valve T1 and a second pinch valve T2, the outer side of the first pinch valve T1 is connected with a first reagent bottle S1, the inner side of the first pinch valve T1 is connected with a first two-way valve E1 in the digestion reaction unit through a three-way joint J, the outer side of the second pinch valve T2 is connected with a second reagent bottle S2, and the inner side of the second pinch valve T2 is connected with a first two-way valve E1 in the digestion reaction unit through the three-way joint J. The upper ends of the two metering pipes are connected with three-way electromagnetic air valves, and the three-way electromagnetic air valves are connected in series linearly and are connected with a peristaltic pump R1 through a pipeline. An ellipsoid cavity is arranged in the middle of the group of transparent quartz metering tubes A1, and the upper end and the lower end of the ellipsoid cavity are respectively provided with a first photoelectric switch liquid level meter and a second photoelectric switch liquid level meter (Y1, Y2); the lower end of the other group of quartz metering tubes is provided with a spherical cavity, a third photoelectric switch liquid level meter and a fourth photoelectric switch liquid level meter (Y3, Y4) are arranged above the ellipsoidal cavity, and the third photoelectric switch liquid level meter and the fourth photoelectric switch liquid level meter are spaced at a certain distance. The spherical cavity can avoid the interference of bubbles generated in the metering process to the metering result. When reagent 1 is metered, the three-way electromagnetic air valve Q on the outer side of the first pinch valve T1 and above A1 of the quartz metering tube A1 is opened, the peristaltic pump R1 rotates clockwise, and the reagent 1 is pumped into the quartz metering tube A1. When the liquid level of the reagent 1 in the metering tube reaches the photoelectric switch Y1 above, the power-on inner side of the three-way pinch valve T1 is opened (the outer side is closed at the moment), the peristaltic pump R1 rotates anticlockwise, and the reagent 1 is injected into the digestion pool. When the liquid level of the reagent 1 drops to the photoelectric switch Y2 at the lower part, the outer side of the pinch valve T1 is opened, and the peristaltic pump R1 is stopped. The metered volume of reagent 1 is equal to the cross-sectional area in the metering tube multiplied by the height difference of the upper and lower level switches. Reagent 2 is metered based on another group of quartz metering tubes, a three-way electromagnetic air valve Q positioned above the metering tube A2 is opened during metering, and other processes are similar to reagent 1 metering. The reagent metering component has high metering precision and good stability, and related results have already applied for invention patent (a liquid volume metering device, CN 108444562A).
The main body of the digestion unit is a quartz digestion tank F, the bottom of the digestion unit is provided with a sample inlet, and the sample inlet is connected with a first two-way valve E1. The upper part of the digestion pool F is connected with a second two-way valve E2 as an air pressure balancing port. The first and second two-way valves are high-pressure-resistant and high-temperature-resistant two-way valves, and are powered on and powered off. The whole external of the digestion tank is wrapped with a heating wire, and the side of the digestion tank is provided with a temperature sensor. The digestion tank is provided with a fixing piece, a limiting supporting bottom support is arranged below the digestion tank, and a protective shell is arranged outside the digestion tank. The outer wall of the digestion tank is provided with a clamping groove, and the heating wire is fixed in the clamping groove. A groove is arranged at the lower position of the middle part of the digestion tank, a temperature sensor is arranged in the groove, and heat-conducting silica gel is filled between the groove and the temperature sensor. The singlechip controls the on-off of the heating wire and collects the data of the temperature sensor; when the digestion is carried out, the reagent and the water sample are sequentially injected into the digestion tank, and the heating wire starts to work. The heating wire is electrically connected with the temperature sensor and the singlechip, the heating wire is controlled by the singlechip, and the singlechip acquires data of the temperature sensor. When the digestion is carried out, a water sample and a reagent are sequentially injected into the digestion tank, and the heating wire starts to work. The first high-pressure-resistant and high-temperature-resistant two-way valve and the second high-pressure-resistant and high-temperature-resistant two-way valve are closed, the digestion pool is in a closed state, and the water sample is ensured to be subjected to thorough digestion reaction. When the temperature value received by the single chip microcomputer from the temperature sensor is lower than a preset low value, the single chip microcomputer keeps the heating wire open to heat the liquid in the digestion tank; when the temperature value received by the single chip microcomputer reaches a preset high value, the heating wire is controlled to be disconnected, heating is stopped, and the phenomenon that the pressure in the cavity is too high due to too high temperature is avoided. And the sample inlet at the bottom is also used as a sample outlet, when the reaction is complete, the first peristaltic pump, the third peristaltic pump and the fourth peristaltic pump are closed, the first two-way valve and the second two-way valve are powered on and opened, the third pinch valve is not powered on, the second peristaltic pump is opened, and the reaction liquid is pumped to the photoelectric detection unit.
The shell of the photoelectric detection unit G is an opaque rectangular box body, one side of the photoelectric detection unit G is provided with a 470nm LED light source G1 with safe voltage, the other side of the photoelectric detection unit G is provided with a diode detector G2, a quartz cuvette G3 is arranged at a position close to the diode detector, and a plurality of optical lenses are arranged among the photoelectric detection unit G, the quartz cuvette G3 and the diode detector, so that light passing through the cuvette can uniformly irradiate the light receiving surface of the whole diode detector. The upper and lower ports of the colorimetric pool G3 are connected with a liquid conveying channel, the upper port of the colorimetric pool G3 is connected with a waste liquid recovery barrel through the liquid conveying channel, the lower port of the colorimetric pool G3 is connected with the outer side of a third pinch valve T3, and the inner side of a third pinch valve T3 is connected with a cleaning water recovery barrel. The LED light source G1 and the diode detector G2 are electrically connected with the single chip microcomputer, and the electric signals collected by the diode detector G2 are transmitted to the single chip microcomputer. During detection, light emitted by the LED light source G1 passes through the cuvette G3 filled with reaction liquid to reach the light receiving surface of the diode detector G2, and the single chip microcomputer collects electric signals from the diode detector G2 and converts the electric signals into light signal intensity.
The 5 sample feeding channels are composed of four peristaltic pumps and three pinch valve matching pipelines, and the 5 sample feeding channels are formed under the working matching of the peristaltic pumps and the pinch valves. The first channel is a reagent 1 sample introduction channel: the second peristaltic pump, the third peristaltic pump and the fourth peristaltic pump (R2-R4) are closed, the first pinch valve T1 is not electrified, after a set amount of solution is extracted, the first two-way valve (E1 and E2) is electrified and opened, the first pinch valve T1 is electrified, the first peristaltic pump R1 is opened, and the reagent 1 is extracted to the digestion unit through the air valve Q; the second channel is a reagent 2 sample feeding channel, the second peristaltic pump, the third peristaltic pump and the fourth peristaltic pump (R2-R4) are closed, the second pinch valve T2 is not electrified, the first two-way valve (E1 and E2) are electrified and opened, the first peristaltic pump R1 is opened, and the reagent 2 is pumped to the digestion unit through the air valve Q; the third channel is a water sample feeding channel, a first peristaltic pump, a second peristaltic pump and a third peristaltic pump (R1-R3) are closed, a first two-way valve and a second two-way valve (E1 and E2) are powered on and opened, and a fourth peristaltic pump R4 is opened to pump a water sample from a water sample reagent bottle S4 into the digestion unit; the fourth channel is a distilled water sample feeding channel, the first, second and fourth peristaltic pumps (R1, R2 and R4) are closed, the first and second two-way valves (E1 and E2) are electrically opened, and the third peristaltic pump R3 is opened to draw distilled water from the distilled water reagent bottle S3 to the digestion unit; the fifth channel is a detection channel, the first, third and fourth peristaltic pumps (R1, R3 and R4) are closed, the first and second two-way valves (E1 and E2) are powered on and opened, the third pinch valve T3 is not powered on, the second peristaltic pump R2 is opened, and the reaction liquid is extracted from the digestion pool F to the photoelectric detection unit.
The second peristaltic pump R2 is connected with a three-way pinch valve T3, the left outer side of the three-way pinch valve T3 is connected with a photoelectric detection unit, and the inner side of the three-way pinch valve T3 is connected with a washing water recovery barrel. One end of the third peristaltic pump R3 is connected with the distilled water reagent bottle S3, the other end of the third peristaltic pump R3 is connected with one end of a three-way connector, one end of the fourth peristaltic pump R4 is connected with the water sample reagent bottle S4, and the other end of the fourth peristaltic pump R4 is connected with the other end of the three-way connector. This three-way connection is also connected to a second peristaltic pump R2 through another three-way connection.
The connection schematic diagram of each electronic element in the utility model is shown in fig. 2, and the singlechip is respectively connected with a three-way electromagnetic air valve Q, first to fourth photoelectric liquid level switches (Y1-Y4), first to fourth peristaltic pumps (R1-R4), first to third pinch valves (T1-T3), a photoelectric detection unit G, a heating wire H, first and second two-way valves (E1, E2) and a temperature sensor.
A water sample test experiment as shown in example 1-2 was performed based on the above water quality chemical oxygen demand online analyzer, and the reagent 1 was a mixed solution of potassium dichromate, silver sulfate and sulfuric acid; the reagent 2 consists of mercury sulfate.
EXAMPLE 1 chemical oxygen demand Low concentration Water sample test (0 to 150mg/L)
The structure of the online analyzer for water quality chemical oxygen demand is shown in fig. 1, before the analyzer operates, reagents 1 and 2 in bottles S1 and S2 and distilled water in a bottle S3 are required to be supplemented, and the analysis is carried out according to the following specific steps:
step 1, pipeline rinsing
And powering on the fourth peristaltic pump, opening the third channel, pumping a proper amount of water sample to rinse the digestion tank, and closing the fourth peristaltic pump. Standing for several seconds, working the second peristaltic pump, opening the fifth channel, pumping the rinsing water sample in the digestion tank into the photoelectric detection unit, and discharging the rinsing water sample into the rinsing water recovery barrel through the colorimetric tank.
And then the second peristaltic pump rotates clockwise, the residual rinsing water in the colorimetric pool is pumped into the pipeline, the third pinch valve is electrified, the second peristaltic pump rotates anticlockwise, and the rinsing water in the pipeline is discharged into the rinsing water recycling bin along the pipeline.
The first pinch valve is not electrified, the module with the air valve Q positioned above the quartz tube A1 is opened, and the first peristaltic pump rotates clockwise to pump the reagent 1 into the reagent metering assembly for metering. After metering is finished, the first and second pinch valves are electrified, the first peristaltic pump rotates anticlockwise to pump the reagent 1 which finishes the metering into the digestion tank, and the module with the air valve Q positioned above the quartz tube A1 is closed. Then the second pinch valve is not electrified, the module with the air valve Q positioned above the quartz tube A2 is opened, the first peristaltic pump rotates clockwise, and the reagent 2 is sequentially pumped into the reagent metering assembly for metering. After metering is completed, the first and second pinch valves are electrified, the first peristaltic pump rotates anticlockwise to pump the reagent 2 which completes the quantitative metering into the digestion tank, and the module with the air valve Q positioned above the quartz tube A2 is closed.
Step 3, sample introduction
And a third channel in the sample introduction channel works, and a certain amount of water sample is extracted to enter the digestion tank to be mixed with the reagent 1/the reagent 2. The flow rate (V) of the peristaltic pump is fixed, the first dosage volume V of the water sample is t multiplied by V, and the water sample is quantified by setting the rotation time (t) of the peristaltic pump.
The sample introduction channels selected in the step 1 and the step 3 need to be the same channel.
Step 4, digestion reaction
A first high-temperature-resistant high-pressure-resistant two-way valve and a second high-temperature-resistant high-pressure-resistant two-way valve in the digestion unit are powered on, and the digestion tank is in a closed state; and (3) opening a heating wire wound around the digestion tank, heating the mixed liquid to 160 ℃, and digesting for 15 minutes to digest the reducing substances in the water sample.
Step 5, colorimetric measurement
After digestion is finished, when the reaction liquid is cooled to a proper temperature, the first two-way valve and the second two-way valve are not electrified, the fifth channel works, the second peristaltic pump rotates anticlockwise, the digested reaction liquid is pumped into the photoelectric detection unit for photoelectric detection, and the absorbance A is measured470。
The mass concentration of the chemical oxygen demand ρ can be calculated by the formula (2)
Wherein,
a-measured target absorbance value (═ A)470)
b1Intercept of calibration curve for low chemical oxygen demand concentration
a1Slope of calibration curve for low COD
After the measurement is finished, the second peristaltic pump rotates clockwise, and the reaction liquid remaining in the colorimetric pool is pumped into the pipeline. And then the third pinch valve is electrified, the second peristaltic pump rotates anticlockwise, and a small amount of color development liquid left in the digestion tank is emptied along the waste liquid pipeline.
Step 6, cleaning the pipeline
And working a fourth sample introduction channel, and extracting distilled water to fill the digestion tank. Subsequently, the second peristaltic pump is turned on to rotate counterclockwise to pump the distilled water into the colorimetric cell in the photoelectric detection unit and to discharge into the washing water recovery tank.
And then the second peristaltic pump rotates clockwise to pump the residual distilled water in the colorimetric pool into the pipeline, then the third pinch valve is electrified, and the fourth peristaltic pump rotates anticlockwise to drain a small amount of distilled water left in the pipeline along the waste liquid pipeline.
The washing was repeated once.
Example 2 chemical oxygen demand high concentration Water sample test (150-1000 mg/L)
The structure and composition, initial state and reagent bottle loading of the water quality chemical oxygen demand online analyzer in the embodiment of the utility model are the same as those in the embodiment 1.
In this example, the chemical oxygen demand high concentration water sample was measured by the same procedure as in example 1 except for the steps 3 and 5. In the step 3, distilled water is required to be introduced to dilute the water sample, and the calibration curve in the step 5 is correspondingly changed, specifically as follows:
and 3, injecting (diluting). For a water sample with high content of reducing substances, the water sample needs to be diluted in the step, distilled water is added through a fourth sample introduction channel according to a certain dilution ratio, and the total volume of the water sample mixed distilled water is consistent with the first dose.
Opening a third channel, namely closing the first peristaltic pump, the second peristaltic pump and the third peristaltic pump, electrically opening the first two-way valve and the second two-way valve, opening the fourth peristaltic pump to extract a water sample, and pumping the water sample into the digestion unit; the third channel is closed, the fourth channel is opened, the first peristaltic pump, the second peristaltic pump and the fourth peristaltic pump are closed, the first two-way valve and the second two-way valve are powered on and opened, and the third peristaltic pump is opened to pump distilled water to the digestion unit; the flow rate (v) of the peristaltic pump is fixed, and the water sample is quantitatively extracted by setting the rotation time (t) of the peristaltic pump
Draw distilled water of volume
The total volume of sample introduction is 10 mL.
Step 5, colorimetric measurement
After digestion is finished, when the reaction liquid is cooled to a proper temperature, the first two-way valve and the second two-way valve are not electrified, the fifth channel works, the second peristaltic pump rotates anticlockwise, the digested reaction liquid is pumped into the photoelectric detection unit for photoelectric detection, and the absorbance A is measured470。
The mass concentration of the chemical oxygen demand ρ can be calculated by the formula (3)
Wherein,
a-measured target absorbance value (═ A)470)
bnIntercept of calibration curve for high chemical oxygen demand concentration
anSlope of calibration curve for high COD
After the measurement is finished, the second peristaltic pump rotates clockwise, and the reaction liquid remaining in the colorimetric pool is pumped into the pipeline. And then the third pinch valve is electrified, the second peristaltic pump rotates anticlockwise, and a small amount of color development liquid left in the digestion tank is emptied along the waste liquid pipeline.
It should be noted that the above-mentioned contents only illustrate the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and it is obvious to those skilled in the art that several modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations fall within the protection scope of the claims of the present invention.
Claims (6)
1. A water quality chemical oxygen demand on-line analyzer is characterized in that: the device comprises a plurality of peristaltic pumps, a plurality of pinch valves, a plurality of three-way joints, a reagent metering unit, a digestion reaction unit, a photoelectric detection unit and a single chip microcomputer; the reagent metering unit is connected to the digestion reaction unit through two reagent sample introduction channels, the digestion reaction unit is connected with the photoelectric detection unit through a detection channel, and the digestion reaction unit is also connected with a distilled water sample introduction channel and a water sample introduction channel; the single chip microcomputer is used for controlling all electronic components in the analyzer;
the reagent metering unit comprises two groups of transparent quartz metering tubes, the lower ends of the two metering tubes are respectively connected with a pinch valve, the outer sides of the two pinch valves are respectively connected with a reagent bottle, and the inner sides of the two pinch valves are connected with the digestion reaction unit; the upper ends of the two metering pipes are connected with three-way electromagnetic air valves, and the three-way electromagnetic air valves are linearly connected in series and connected with the first peristaltic pump; the liquid level meters are respectively arranged on the upper part and the lower part of the side surface of the metering pipe, and the generated electric signals indirectly control the three-way electromagnetic air valve, the first and the second pinch valves and the first peristaltic pump to operate through the singlechip;
the digestion reaction unit comprises a quartz digestion tank, the bottom of the digestion tank is provided with a sample inlet, the sample inlet is connected with a first two-way valve, and the upper part of the digestion tank is connected with a second two-way valve as a gas pressure balancing port; a heating wire is wrapped outside the whole digestion tank, and a temperature sensor is arranged on the side edge of the digestion tank; the single chip microcomputer collects data of the temperature sensor and controls the on-off of the heating wire; the first two-way valve is connected with one end of the second peristaltic pump, and the other end of the second peristaltic pump is connected with the third pinch valve;
the shell of the photoelectric detection component is an opaque rectangular box body, an LED light source is arranged on one side of the shell, a photocell is arranged on the other side of the shell, an optical lens is arranged between the photoelectric detection component and the LED light source, a quartz colorimetric pool is arranged at a position close to the photocell, and a lower opening of the colorimetric pool is connected with the outer side of a third pinch valve; the single chip microcomputer controls the LED light source and collects the electric signal of the photocell;
the water sample sampling channel comprises a water sample reagent bottle and a fourth peristaltic pump, the water sample reagent bottle is connected with the fourth peristaltic pump through a pipeline, and the fourth peristaltic pump is connected to a first two-way valve of the digestion reaction unit;
the distilled water sample introduction channel comprises a distilled water reagent bottle and a third peristaltic pump, the distilled water reagent bottle is connected with the third peristaltic pump through a pipeline, and the third peristaltic pump is connected to a first two-way valve of the digestion reaction unit.
2. A water quality chemical oxygen demand on-line analyzer as claimed in claim 1, wherein: one of the two metering tubes is provided with an ellipsoidal cavity in the middle, and the two liquid level meters are respectively positioned at the upper end and the lower end of the ellipsoidal cavity; the lower end of the other metering tube is provided with an ellipsoidal cavity, and the two liquid level meters are both positioned above the ellipsoidal cavity.
3. A water quality chemical oxygen demand on-line analyzer as claimed in claim 1, wherein: the inner side of the pinch valve is opened and the outer side is closed when the pinch valve is powered on, the inner side of the pinch valve is closed and the outer side is opened when the pinch valve is powered off, and the two-way valve is opened when the pinch valve is powered on and closed when the pinch valve is powered off.
4. A water quality chemical oxygen demand on-line analyzer as claimed in claim 1, wherein: the two-way valve is a high-pressure-resistant and high-temperature-resistant two-way valve.
5. A water quality chemical oxygen demand on-line analyzer as claimed in claim 1, wherein: the LED light source is a 470nmLED light source.
6. The water quality chemical oxygen demand on-line analyzer according to claim 1, characterized in that: the sample introduction channel, the detection channel, the distilled water sample introduction channel and the water sample introduction channel are all formed by oxidation-resistant and corrosion-resistant hoses.
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| CN202220153124.3U CN216978819U (en) | 2022-01-20 | 2022-01-20 | Water quality chemical oxygen demand online analyzer |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115824988A (en) * | 2022-12-26 | 2023-03-21 | 陕西省化工产品质量检验检测站有限公司 | Device and method for automatically and rapidly determining chemical oxygen demand |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115824988A (en) * | 2022-12-26 | 2023-03-21 | 陕西省化工产品质量检验检测站有限公司 | Device and method for automatically and rapidly determining chemical oxygen demand |
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