CN115112826A - Multi-metering-tube water quality measuring device - Google Patents

Abstract

The invention discloses a water quality measuring device. The liquid level sensor is not influenced by light rays and protected by a cassette by using a plurality of metering tubes and capacitors, and can be developed for visual inspection or camera monitoring with scales. The metering tube measures the volume of the water sample and the various reagents. Each reagent is an independent channel, liquid can be fed and metered simultaneously, liquid does not flow through the discharge valve or the nine-way valve, reagent mixing and pollution cannot occur, the liquid channel does not need to be cleaned repeatedly, measuring time is shortened, the influence of abrasion of a transmission pump and change of pipeline flow is avoided, and frequent maintenance and regular error check are not needed. Through the action of the drive pump of metering tube sensor closed-loop control transmission liquid, the multisensor is arranged and is formed the sensor chi, and the titration reagent liquid volume of titration reaction is measured accurately, need not change, and direct substitution chemical formula calculates, and reduction error directly perceived. According to the needs, the number and the channel of the metering pipes can be flexibly expanded, the amount of each chemical liquid is independently formulated, and the chemical liquid metering device is suitable for complex chemical reactions.

Description

Multi-metering-tube water quality measuring device

Technical Field

The invention discloses a water quality measuring device. A plurality of metering tubes are used, each metering tube is provided with a liquid level sensor for measuring the volume of each liquid, and the liquid is sent into the digestion chamber through an independent channel for measuring the water quality parameters through photoelectric analysis.

Background

The country has paid more and more attention to environmental protection, and water resource measurement and water quality analysis, which are important items in environmental protection, are urgently needed to be perfected. The existing water quality measuring instrument has a design principle which is not advanced enough and is not strict enough, and needs to be improved as soon as possible. Taking the online ammonia nitrogen measuring instrument which is most used in water quality detection as an example, the online ammonia nitrogen measuring instrument is classified according to the measuring method, and the online ammonia nitrogen measuring instrument mainly has two types: the first method is to simulate the operation and measurement method of a laboratory, for example, as shown in fig. 3, according to the chemical experiment formula, liquid quantities of various liquids are sequentially extracted by pumps with various quantities, and are sequentially sent into a digestion chamber, a photoelectric tube detects the color of a chemical reaction, and the color is analyzed by voltage, so that water quality parameters are obtained, and the digestion chamber is emptied and cleaned after the measurement is finished. The disadvantages are that: different measurement experiments correspond to different formulas, the experimental formulas correspond to peristaltic pumps with different configuration combinations, the flexibility is poor, and the universal and the expansion are difficult. Because the liquid quantity is measured according to the rotation number and the angle of the peristaltic pump, the liquid volume is not directly measured, the liquid volume is indirectly measured by using an intermediate transmission medium, the influence of flow change such as abrasion of the peristaltic pump and corrosion or bubbles or residue of a transmission channel is not considered, the liquid inlet control method belongs to open-loop control, liquid inlet errors possibly exist, the liquid inlet control method does not conform to an automatic control principle, and the precision can be ensured by timing verification. Because the peristaltic pump is exposed to liquid, it requires cleaning and maintenance. A plurality of peristaltic pumps with different quantities are correspondingly used in each formula, so that the cost is high, and the actual use amount is gradually reduced. The second is a measurement method that shares the metering tube and the discharge valve passage, and a method that uses a relatively large amount is now used. Example fig. 4, a set of common channel apparatus is used, comprising: peristaltic pump, metering tube, discharge valve or rotary nine-way valve, digestion chamber, electromagnetic valve, etc. The motor drives the peristaltic pump to pump liquid, the liquid is sent into a shared metering tube, the photoelectric correlation sensor measures the liquid level of the metering tube, the liquid level of the liquid is metered, the liquid level of a water sample or the liquid level of various reagents are sequentially sent into the digestion chamber according to the switching of the discharge valve or the rotary nine-way valve, the photoelectric tube detects the color of chemical reaction and carries out voltage analysis, the water quality parameter is obtained, and the discharge and cleaning are carried out after the measurement. The disadvantages are that: the shared metering pipe limits the reagent proportion of the chemical formula, the reagent proportion can only be an integral multiple relation, the optimal configuration cannot be achieved, and because the metering pipe and the discharge valve or the rotary nine-way valve all adopt the shared liquid channel, in order to avoid the liquid mixing of various liquids, the step of cleaning the metering pipe and the liquid channel is required to be added in the middle, and the measurement time is prolonged. Even if the cleaning is carried out for multiple times, the cleaning can not be completely carried out theoretically, the physical structures of the exhaust valve and the rotary nine-way valve are shown in figure 5, a shared channel exists, liquid mixing cannot be avoided, and if liquid in the shared channel in the exhaust valve flows back, reagents and reagent barrels can be polluted, so that the subsequent measurement is inaccurate. In a strict sense, the mixing of the chemical reagents in the transmission channel before the chemical reagents enter the reaction kettle is not allowed, and the measurement method cannot meet the definition of a chemical experiment. Therefore, the two types of measuring instruments can only measure, but cannot completely ensure the reliability and the precision of the measurement.

Disclosure of Invention

The invention relates to a water quality measuring device, which is shown in figure 1. The method is characterized in that: using a plurality of metering tubes with sensors, fig. 2, the portion volumes corresponding to the various liquids were measured. The metering tube has a level sensor that measures the liquid in the metering tube. The level sensor may be a photoelectric or capacitive sensor or a transmission-reception correlation sensor, or the like. The recommended adoption electric capacity response level sensor does not receive the change or the interference influence of light, and the measuring tube does not need the magazine protection, can develop the range estimation or the camera control of taking the scale. Each metering tube has at least one level sensor, and if there are multiple level sensors, each liquid can take multiple liquid portions. The water quality measuring device is provided with independent liquid channels corresponding to each reagent, liquid does not flow through a row valve or a rotary nine-way valve, reagent mixing and reagent barrel pollution cannot occur, the liquid channels do not need to be cleaned repeatedly, measuring time is shortened, the abrasion of a transmission pump and the influence of pipeline flow change are avoided, the arrangement number of sensors on a measuring pipe is increased, a sensor ruler is combined, a graph 2 is shown, the state of the sensor ruler is read in a time-sharing mode, and the liquid level change liquid quantity in the measuring pipe is measured. The universal measuring equipment can accurately measure the liquid amount consumed by the titration reagent of the titration reaction and combine to manufacture a plurality of measuring methods. The metering tube is a liquid volume measuring device, is not influenced by a transmission medium, and does not need frequent maintenance and periodic error check. Because each reagent is an independent channel, the simultaneous liquid feeding-metering-feeding into the digestion chamber can be realized, and the measurement time is reduced. The metering tube measures, the action of a driving pump for transmitting liquid is controlled in a closed-loop mode through a metering tube sensor, the liquid level of the liquid in the metering tube is accurately measured, namely the volume of the liquid is measured, conversion is not needed, the liquid is directly substituted into a chemical formula for calculation during titration reaction, and errors are visually reduced. The measuring channels of the multiple metering tubes can flexibly expand the number and the channels of the metering tubes according to requirements, the amount of each chemical liquid in the formula is independent, and the method is suitable for complex chemical reactions. The liquid level can be changed by changing the inner diameter of the metering pipe, and the liquid level measurement accuracy is higher as the inner diameter of the metering pipe is thinner. The liquid level can be changed by changing the installation position of the measuring tube sensor, the liquid level is changed, the fine adjustment of the upper installation position and the lower installation position of the measuring tube sensor can be realized, and the expected liquid level can be accurately adjusted. The quantity of the sensors on the measuring pipe is increased, the sensors are arranged at fixed intervals to form a sensor ruler, the state of the sensor ruler is read in a time-sharing mode, and the liquid quantity of the liquid level change in the measuring pipe is measured. The characteristic of the sensor ruler is utilized, the sensor ruler is applied to titration reaction, and the liquid volume of the titration liquid can be accurately measured. Example potassium permanganate titration reaction: the inner diameter of the measuring tube is 2mm, the radius is 1mm, the sensor mounting interval of the sensor ruler is 10mm, and the liquid volume of the adjacent liquid level sensor in the measuring tube is equal to 0.0314 milliliter when the base area x is high = pi 1 x 10 ═ 31.4 microliter divided by 1000. Because the titration calibration liquid quantity is defined as 1/20 ml, which is equal to 0.05 ml, the measuring liquid quantity of the metering tube is less than the calibration liquid quantity, and the titration accuracy meets the requirement, the titration method is applicable to the titration reaction. At the moment, the titration liquid is firstly sucked to reach the initial high liquid level of the sensor ruler, the liquid level liquid with the length of 10mm is used for each titration by closed-loop control until the titration discoloration reaction is reached, the counting and measuring state of the sensor ruler is read at the moment, the liquid level of the titration liquid which is obtained by measuring and changing twice is compared, and the liquid level is substituted into a chemical calculation formula, so that the water quality parameter of the measured water sample can be calculated. The above is only simple calculation, and has control allowance, if the inner diameter of the measuring pipe is reduced, the installation distance between the adjacent sensors of the sensor ruler is reduced, and the measuring resolution and precision can be further improved. The currently popular titration apparatus has a high precision error area, which is how to improve the precision of each drop, for example, a plunger pump using open loop control, etc., and fig. 6 shows that the error is the precision of the plunger pump multiplied by the number of drops titrated, which is a multiple accumulated error. The control object of the titration device is an intermediate medium-plunger pump, the more the titration number is, the larger the error is, and the high-precision plunger pump is high in cost and needs to be maintained and calibrated. The metering tube-sensor ruler has the advantages that the control object is the final target, namely titration liquid, the error does not need to be measured with high precision, the total error is calculated, the control does not need to be performed with high precision, the realization is easy, the closed-loop control does not need to be calibrated, and the cost is low. The invention relates to a multi-metering-tube measuring device which is mainly designed for water quality measurement. However, the working principle and structure of the multi-metering tube are also applicable to other fields, such as: chemical experimental reactions, chemical industrial control, and the like, all accord with the application of the invention.

Drawings

Fig. 1 is a liquid pipeline structure diagram of a water quality measuring apparatus of the present invention: the peristaltic pump 1 is a flexible fully-sealed hose inside, a motor drives the flexible fully-sealed hose to rotate forwards or reversely, liquid is guided to be sucked upwards or discharged downwards from a metering tube through a sealed pipeline, the liquid flows up and down in a liquid storage tube of the metering tube, the liquid level height is realized by a liquid level sensor closed-loop control peristaltic pump, and a discharge valve above the metering tube and the peristaltic pump are not in contact with the liquid. And 2, a discharge valve is used for gating a driving air channel which corresponds to the liquid and the metering pipe and is connected with the peristaltic pump, and the air channel has no liquid and cannot mix the liquid. 3 is a liquid storage pipe, 4 is an auxiliary observation scale, 5 is a liquid level sensor, a program closed loop controls the peristaltic pump to rotate forwards or backwards and start or stop, a low level liquid level sensor controls the liquid quantity-liquid quantity sent into the digestion chamber, a high level liquid level sensor is an upper limit sensor of the liquid level, the peristaltic pump is controlled to stop rotating forwards, the liquid is guaranteed not to overflow out of the storage pipe of the metering pipe, the liquid is prevented from upwards entering a drain valve and the peristaltic pump, and the metering pipe with the liquid level sensor is formed by combining the 3, 4 and 5. And 6, a sensor ruler which is formed by arranging a plurality of liquid level sensors at fixed intervals and can be used for titration measurement. 7 is a three-way electromagnetic valve, 8 is a two-way electromagnetic valve, 9 is a digestion chamber, and 10 is a photoelectric tube, and the three-way electromagnetic valve is used for color analysis-conversion voltage or current-water quality parameter measurement. The piping structure diagram shows only the connection control relationship and does not represent a specific installation position. Taking distilled water as an example: the discharge valve 2 above the metering tube and the three-way electromagnetic valve 7 below the metering tube gate the upper and lower channels of the distilled water metering tube 3, the peristaltic pump 1 rotates forwards to suck liquid into the metering tube low-level sensor 5 to stop, the three-way electromagnetic valve 7 below the metering tube is switched to a digestion chamber channel, the three-way electromagnetic valve 7 below the digestion chamber is communicated with the electromagnetic valve 8, the peristaltic pump 1 rotates backwards to push the liquid in the metering tube 3 to be completely sent into the digestion chamber, the electromagnetic valve 8 below the digestion chamber is blocked, and the peristaltic pump 1 stops. This is a flow of distilled water into the digestion chamber after being metered through the metering tube. The flow of sending the water sample into the digestion chamber is similar to that of the above: only the lower three-way solenoid valve 7 is gated to the water sampling channel. The flow of feeding the reagent A, B, C liquid into the digestion chamber after being metered through respective metering pipes is as follows: the discharge valve 2 gates the metering pipe channel corresponding to the reagent liquid, the peristaltic pump 1 sucks the liquid into the metering pipe low-level sensor 5 to stop, the three-way electromagnetic valve 7 below the metering pipe is switched to the digestion chamber channel, and the reagent is sent into the digestion chamber 9 from the respective independent channel above the digestion chamber. The distilled water cleaning metering pipe, the digestion chamber and the waste liquid discharge flow: the metering tube channel of the distilled water is gated by the discharge valve 2, the peristaltic pump 1 sucks liquid to the metering tube high-level sensor 5 to stop, the three-way electromagnetic valve 7 is switched and the electromagnetic valve 8 is switched on to clear up the channel below the chamber, the distilled water is sent to clear up the chamber and cleaned, the three-way electromagnetic valve 7 is switched to the waste liquid channel below the chamber, and the waste liquid is discharged to the waste liquid barrel. Depending on the chemical formulation, the liquid in the bulk can be divided into several portions or portions, which are metered into the digestion chamber. And other operation flows are analogized according to the states of the pipeline and the electromagnetic valve. The leftmost side is a special passage for titrating liquid, the electromagnetic valve 8 on the upper left side is turned off and sealed, the idle stroke of a pipeline for titrating liquid is eliminated by manual operation, the titrating liquid reaches a titrating pipe opening in the digestion chamber, and then an automatic titrating program is started: the discharge valve 2 above the metering tube and the three-way electromagnetic valve 7 below the metering tube are switched to a titration liquid channel, the peristaltic pump 1 rotates forwards to suck titration liquid to a high-level sensor of a sensor ruler 6 as an initial liquid level, the peristaltic pump 1 stops, the three-way electromagnetic valve 7 below the metering tube is switched to a digestion chamber channel to prepare for releasing the titration liquid to enter the top end of the digestion chamber, titration is carried out, the peristaltic pump 1 is controlled to rotate reversely in a micro motion way or the electromagnetic valve 8 is controlled to be switched on and off quickly, multi-step micro motion and counting are carried out (for example, the step 10 of debugging and controlling the micro motion is approximately equal to one sensor interval, when the liquid level is reduced to the induction of the next sensor, micro motion counting is cleared), meanwhile, the color of the liquid is detected and judged through a photoelectric tube 10 of the digestion chamber until the liquid in the digestion chamber 9 is changed, the state of the sensor ruler 6 is read, and then (10-micro motion counting) is added as the current liquid level which is determined by the initial liquid level and the current liquid level, the liquid level is compared to obtain the liquid level, namely the liquid amount used by the titration liquid, and the liquid level is substituted into a chemical calculation formula to calculate the water quality parameter of the detected water sample. If the amount of the titrant used exceeds one sensor ruler, the steps can be repeated, and the amount of the titrant is calculated in an accumulated way, and the control precision of the amount of the titrant is about 1/10.

FIG. 2 is a structural diagram of a measuring tube, 1 is a liquid storage tube, 2 is a low level liquid level sensor for controlling the amount of liquid-liquid volume sent into a digestion chamber, 3 is a high level liquid level sensor for controlling the upper limit sensor of the liquid level to stop a peristaltic pump and also for controlling the high level liquid volume of cleaning liquid to be sent into the digestion chamber, 4 is an auxiliary observation scale which is used as a reference object for installing and adjusting the liquid level sensor and is also used for visual observation or camera monitoring, 5 is for increasing the number of the sensors on the measuring tube, the sensors are arranged at fixed intervals to form a sensor ruler, the state of the sensor ruler is read in a time-sharing manner, and the liquid level in the measuring tube is measured to change.

Fig. 3 is a diagram of a liquid pipeline structure of a measuring instrument for detecting ammonia nitrogen parameters of water quality in the early stage, and an example diagram of a measurement method in a simulation laboratory: 1 is a peristaltic pump, 2 is a digestion chamber, 3 is a photocell, and 4 is a solenoid valve. The peristaltic pumps 1 with various quantities are used for sequentially pumping the liquid quantities of various liquids, the liquids are sequentially sent into the digestion chamber 2, the photoelectric tube 3 is used for detecting the color, voltage or current of the chemical reaction and analyzing to obtain water quality parameters, the electromagnetic valve 4 is switched on after the measurement is finished, and the digestion chamber 2 is emptied.

Fig. 4 is a diagram of a liquid pipeline structure of a measuring instrument for detecting ammonia nitrogen parameters of existing popular water quality, and a diagram of a measurement method of a drain valve or a nine-way valve in an example: 1 is a peristaltic pump, 2 is a metering tube with a photoelectric correlation liquid level sensor, 3 is a discharge valve or a nine-way valve, 4 is a high-temperature resistant electromagnetic valve, 5 is a digestion chamber, and 6 is an electromagnetic valve. Using a common channel apparatus comprising: peristaltic pump, metering tube, discharge valve or rotary nine-way valve, digestion chamber, electromagnetic valve, etc. The peristaltic pump 1 pumps liquid and sends the liquid into the shared metering tube 2, the photoelectric correlation sensor measures the liquid level of the metering tube 2 and the liquid amount of the liquid, the liquid amount of a water sample or various reagents is sent into the digestion chamber 5 in sequence according to the switching of the discharge valve or the rotary nine-way valve 3 and the matching control of the electromagnetic valve 6, the photoelectric tube detects the color, voltage or current analysis of chemical reaction to obtain water quality parameters, and the digestion chamber 5 is emptied, cleaned and finished after the measurement. Because of the sharing of the metering tube and the low level sensor, the ratio of various reagents fed into the digestion chamber can only be an integral multiple, for example: the liquid amount of 1 part of low liquid level of the reagent A is matched with the liquid amount of 2 parts of low liquid level of the reagent B, and the formulas of the two reagents are 1: 2, but not 1: 1.5, the shared liquid level sensor cannot be independently arranged, so that the accuracy of a chemical formula is limited, and the reagent cannot reach the optimal configuration.

FIG. 5 is an exemplary illustration of a row valve and a rotary nine-way valve: the liquid pipeline diagram symbol of the row valve or the nine-way valve 1 can be one path of eight paths, 2, 3, 4 and 5 are sectional diagrams of various row valve structures, each interface is controlled by an electromagnetic valve, a middle wide channel is a shared channel, two ends of the shared channel can be connected with a pipe to be used as a main channel, when the selected path is switched, liquid flows through the middle shared channel, mixed liquid exists, if the electromagnetic valve of the interface is in failure or is in error in operation, the liquid of the shared channel flows back, reagent and a reagent barrel can be polluted, and risk factors exist, so that later measurement errors are caused. 6 is a structural example diagram of the rotary nine-way valve: one path is used for selecting eight paths, and the corresponding paths are switched in a rotating mode, because the rotating mode needs rotating gaps, the larger the gaps are, the more liquid leakage and liquid mixing are. The middle short channel is a common channel, and a mixed liquid also exists.

Fig. 6 is a titration example of a plunger or syringe pump: 1 is plunger pump or syringe pump, 2 is the solenoid valve, 3 is cleared up the room, 4 is the photoelectric tube, and linear motor drive plunger pump or syringe pump 1 absorbs the titration liquid, and the program switches on solenoid valve 2, and plunger pump or syringe pump 1 extrudees the titration liquid with fixed stroke and drips into and clears up room 3, and photoelectric tube 4 detects and clears up the interior liquid colour of room, and the repeated titration is until the liquid discolours. The dosage of the titration liquid is the liquid dosage of each titration multiplied by the number of times of titration, and the liquid dosage control precision of the titration liquid depends on the precision of a plunger pump or a syringe pump. The liquid amount per drop is controlled in an open loop manner, requiring regular maintenance and calibration.

Claims (7)

1. A water quality measuring device is characterized in that: the volume of the portion corresponding to each liquid was measured using a plurality of metering tubes with sensors.

2. The water quality measuring apparatus according to claim 1, wherein: the metering tube has a level sensor that measures the liquid in the metering tube.

3. The fluid level sensor of claim 2, wherein: a photoelectric sensing sensor.

4. The fluid level sensor of claim 2, wherein: a capacitive sensing sensor.

5. The fluid level sensor of claim 2, wherein: transmit-receive correlation sensors.

6. The water quality measuring apparatus according to claim 1, wherein: the quantity of the sensors on the measuring pipe is increased, the sensors are arranged at fixed intervals to form a sensor ruler, the state of the sensor ruler is read in a time-sharing mode, and the liquid quantity of the liquid level change in the measuring pipe is measured.

7. The water quality measuring apparatus according to claim 1, wherein: the metering tube is provided with auxiliary observation scales, is used as a reference object for installing and adjusting the liquid level sensor, and is also used for visual inspection or camera monitoring.

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