CN111006934A

CN111006934A - Potassium permanganate index analyzer

Info

Publication number: CN111006934A
Application number: CN201911379561.6A
Authority: CN
Inventors: 汤杰; 潘浙钗; 崔海松; 龙见翔; 杨朋飞; 朱竞元
Original assignee: Hangzhou Lujie Environmental Science And Technology Co ltd
Current assignee: Hangzhou Lvjie Technology Co ltd
Priority date: 2019-12-27
Filing date: 2019-12-27
Publication date: 2020-04-14
Anticipated expiration: 2039-12-27
Also published as: CN111006934B

Abstract

The embodiment of the invention discloses a potassium permanganate index analyzer, which comprises a digestion cup body, a heating module arranged on the outer side of the digestion cup body, and a temperature controller connected with the heating module. The heating module comprises a heating belt which is attached and wound on the outer side of the digestion cup body at equal intervals, and is used for fixing the heating belt and arranging a plurality of salient points and two winding posts on the outer side of the digestion cup body. The starting end and the terminal end of the heating belt are respectively connected with the corresponding winding posts through wiring terminals; the first type of salient points are positioned on the left side and the right side of the digestion cup body, the salient points on the same side are distributed at equal intervals, the second type of salient points are positioned below the starting winding ring and the stopping winding ring of the heating belt, the salient points on the same horizontal plane are symmetrically distributed on the front side and the rear side of the digestion cup body, and the number of the salient points is determined by the length and the width of the heating belt. The temperature controller controls the heating power of the heating module according to the real-time temperature and the standard temperature curve of the reaction solution. This application is favorable to realizing high-efficient, accurate water quality testing.

Description

Potassium permanganate index analyzer

Technical Field

The embodiment of the invention relates to the technical field of surface water quality detection, in particular to a potassium permanganate index analyzer.

Background

Along with the rapid development of industry, industrial water and industrial waste are discharged more and more, river and lake pollution accidents occur frequently, the water quality of daily life water also becomes worse gradually, and how to monitor the water quality safely and reliably and conveniently becomes a problem to be solved urgently.

The permanganate index is used as one of the main indexes of the surface water quality, and can effectively represent the organic matter pollution degree in the water body. The determination method of the water quality permanganate index comprises the steps of adding 100mL of sample, 5mL of sulfuric acid and 10mL of potassium permanganate into a 250mL conical flask, putting the conical flask into a water bath kettle, carrying out boiling water bath for 30min, adding 10mL of sodium oxalate, and carrying out back titration by potassium permanganate until the color becomes reddish. Finally, the water quality permanganate index was calculated by titrating the volume of potassium permanganate consumed. However, since many organics are only partially oxidized, volatile organics are not included in the measured values, and the permanganate index is not an indicator of theoretical oxygen demand or total organic content. In addition, potassium permanganate is easily decomposed when being heated, and can also be used as an oxidant to oxidize organic matters to generate redox reaction, and the reaction rate is sensitive to the reaction temperature. Different reaction temperatures can finally cause uncontrollable reaction processes, differences exist, different oxidation rates are obtained, and concentration values obtained by testing water samples containing different substances are also different. Therefore, the measured value is greatly influenced by the time and temperature of the reaction process, and the temperature control curve of the instrument needs to be completely consistent with the temperature control curve of the laboratory method specified by the national standard.

The potassium permanganate index analyzer is a water quality measuring instrument prepared by a water quality permanganate index determination method, and the potassium permanganate index analyzer realizes heating digestion of water quality by installing a digestion cup. However, the digestion cup in the related art has poor temperature control effect in the heating mode, the water quality is heated unevenly, for example, an aluminum block or a heating wire is adopted, the processing technology is complex, the safety and reliability are not high, and the oxidation rate of organic matters is different from the oxidation rate of national standards, so that the measured value of an instrument is unstable or inaccurate.

Disclosure of Invention

The embodiment of the disclosure provides a potassium permanganate index analyzer, which realizes high-efficiency and accurate water quality detection.

In order to solve the above technical problems, embodiments of the present invention provide the following technical solutions:

the embodiment of the invention provides a potassium permanganate index analyzer, which comprises a digestion cup body, a heating module and a temperature controller, wherein the heating module is arranged on the outer side of the digestion cup body;

the heating module comprises a heating belt which is attached and wound on the outer side of the digestion cup body at equal intervals, a plurality of salient points which are used for fixing the heating belt and are arranged on the outer side of the digestion cup body, and two winding posts; the starting end and the terminal end of the heating belt are respectively connected with the corresponding winding posts through wiring terminals; the first type of salient points are positioned on the left side and the right side of the digestion cup body, the salient points on the same side are distributed at equal intervals, the second type of salient points are positioned below the starting winding ring and the ending winding ring of the heating belt, the salient points on the same horizontal plane are symmetrically distributed on the front side and the rear side of the digestion cup body, and the number of the salient points is determined by the length and the width of the heating belt;

the temperature controller is used for controlling the heating power of the heating module according to the real-time temperature of the reaction solution in the digestion cup and a standard temperature curve so as to keep the real-time temperature of the reaction solution consistent with the corresponding target temperature on the standard temperature curve.

Optionally, the digestion cup further comprises a hardware temperature control module connected in series with the heating module, and the hardware temperature control module is used for disconnecting a connection circuit between the heating module and a power supply when the temperature of the digestion cup body exceeds a temperature threshold value, so that the heating module stops heating the reaction solution;

the hardware temperature control module comprises a first wiring terminal, a fuse and a second wiring terminal; one end of the fuse is connected with one end of the heating belt through the first connecting terminal, the other end of the fuse is connected with the winding post through the second connecting terminal, and the fuse is arranged outside the digestion cup body in an adherent manner; the fuse is a soluble alloy type temperature fuse, and the operating temperature of the soluble alloy type temperature fuse is the same as the temperature threshold.

Optionally, the target adherence position of the fuse on the outer side of the digestion cup body is determined according to the position sensing temperature value, the work limitation condition and the optimal position point selection condition of the fuse at different height positions on the outer side of the digestion cup body;

the position sensing temperature value is the sum of a temperature value of the heating belt for heating the digestion cup body, a radiation temperature value in the heating process of the heating belt and a temperature value of the heating belt transmitted to the fuse through a lead; the working limiting conditions are that the fuse position sensing temperature value is smaller than the fuse working temperature in the normal temperature control process, the fuse position sensing temperature value is larger than the fuse action temperature in the empty cup abnormal heating process, and the fuse position sensing temperature value is larger than the fuse action temperature in the water abnormal heating process; the optimal position point selection condition is that the time value of the time required from the start of abnormal heating to the fusing of the fuse at the target adherence position is shortest and not more than a first time threshold value;

the position sensing temperature value is determined according to a prestored temperature-time curve graph; the temperature-time profile comprises a first curve, a second curve, and a third curve; the first curve is generated according to the change relation of the temperature of the heating zone for heating the digestion cup along with time in the normal temperature control process of the digestion cup, the empty cup full-power heating process and the full-power heating process of water in the cup body; the second curve is generated according to the change relation of the radiation temperature in the heating process of the heating belt along with time in the normal temperature control process of the digestion cup, the full-power heating process of an empty cup and the full-power heating process of water in the cup body; and the third curve is generated according to the change relation of the temperature transmitted to the fuse by the heating belt through a wire along with time in the normal temperature control process of the digestion cup, the full-power heating process of the empty cup and the full-power heating process of the water in the cup body.

Optionally, the fuse is a soluble alloy type thermal fuse, and the operating temperature of the soluble alloy type thermal fuse is the same as the temperature threshold;

one end of the soluble alloy type temperature fuse is connected with the first terminal through a third winding post, and the other end of the soluble alloy type temperature fuse is connected with the second terminal through a fourth winding post; the third winding post and the fourth winding post are used for fixing the soluble alloy type temperature fuse at a target height; the distance between the fusible alloy type thermal fuse and the bottom of the digestion cup was 16.5cm, and the distance between the heating coil winding circle closest to the top of the digestion cup was 0.5 cm.

Optionally, the hardware temperature control module further includes an emergency connection sub-module, where the emergency connection sub-module is configured to communicate a circuit between the heating module and the power supply when the temperature of the digestion cup body exceeds a temperature threshold value, so that the heating module continues to heat the reaction solution;

the emergency connection sub-module comprises a first lead and a second lead, one end of the first lead is connected with the first wiring terminal, and the tail end of the other end of the first lead is provided with a first connection end; one end of the second wire is connected with the second wiring terminal, and the tail end of the other end of the second wire is provided with a second connecting end; and when the second connecting end is connected with the second connecting end in an inserting mode, the circuit between the heating module and the power supply is communicated.

Optionally, the digestion cup further comprises a liquid level alarm system arranged on the sample injection pipeline and used for giving an alarm prompt when the volume of the solution inside the digestion cup body is monitored to be lower than a preset volume threshold value within a preset time period;

the liquid level alarm system comprises a photoelectric isolator and a voice alarm, and the photoelectric isolator is connected with the voice alarm.

Optionally, the length of the heating belt is calculated according to the heating power, the resistivity of the heating belt and the working voltage of the heating belt; the heating belt is made of cadmium-nickel materials; the heating belt has a length of 1.4m, a width of 3mm and a thickness of 0.25 mm.

Optionally, the distance between the first type of bumps positioned on the same side is calculated according to the length and the width of the heating belt and the diameter of the cup body of the digestion cup; the spacing between the bumps of the first type, which are located on the same side, is 4.5 mm.

Optionally, the digestion cup further comprises a stirrer positioned at the bottom end inside the cup body of the digestion cup, the rotation speed of the stirrer is increased along with the increase of the volume of the reaction solution, and the rotation speed is automatically adjusted according to the volume of the reaction solution and a preset stirring rotation speed adjusting coefficient.

Optionally, the digestion cup further comprises a heat radiation fan positioned outside the digestion cup body; the rotation speed of the heat radiation fan is increased along with the increase of the temperature of the digestion cup body, and the rotation speed is automatically adjusted according to the temperature of the digestion cup body and a preset fan rotation speed adjusting coefficient.

Optionally, the temperature controller is configured to implement heating temperature control of the digestion cup when executing a PID computer control program stored in the memory; the temperature controller includes:

the first heating module is used for heating by adopting first power and adjusting the first power by utilizing a self-adaptive adjusting coefficient if the current temperature of the reaction solution is not more than 50% of the corresponding target temperature value on the standard temperature curve; the self-adaptive adjusting coefficient is generated according to theoretical time required by the current temperature value to rise to the target temperature value in the first preset power heating process and actual time required by the current temperature value in the actual heating process;

the second heating module is used for heating according to a second power value if the current temperature of the reaction solution is greater than 50% of the corresponding target temperature value on the standard temperature curve and is not greater than 85% of the target temperature value;

the third heating module is used for heating according to a third power value if the current temperature of the reaction solution is more than 85% of the target temperature value and is not more than-0.5 ℃ of the target temperature value;

and the fourth heating module is used for heating according to a fourth power value if the difference value between the current temperature of the reaction solution and the target temperature value is greater than 0.5 ℃ and not greater than 0 ℃.

Optionally, the heating system further comprises a heating module operating state monitor connected with the temperature controller; the heating module running state monitor is used for detecting the using state of the heating module according to self-adaptive adjusting coefficients automatically generated by the temperature controller at different moments in the using process of the heating module; the heating module operating condition monitor comprises:

the delivery standard detection module is used for judging that the heating module meets delivery standards if the self-adaptive adjustment coefficient automatically generated by the temperature controller when the heating module heats for the first time is not greater than a first preset threshold;

and the aging detection module is used for judging that the heating module is aged if the self-generated self-adaptive adjustment coefficients of the temperature controller in the using process of the heating module are all larger than a second preset threshold value within a preset time period.

Optionally, the first heating module is configured to adopt Power _ k₁Value heated, Power _ k₁＝90％*P_max，P_maxIs the maximum heating power;

the second heating module is used for adopting Power _ k₂Value heated, Power _ k₂＝P₂+I₂+D₂，

The preset P power coefficient of the heating stage of the second heating module is shown, and heatRef is the self-adaptive adjusting coefficient;

the preset I power coefficient, Temp _ SubSum, of the heating stage of the second heating module₂The temperature difference Temp _ Sub when the difference between the current temperature and the target temperature is less than 1.5 DEG C₂An accumulated value of (d);

the third heating module is used for adopting Power _ k₃Value heated, Power _ k₃＝P₃+I₃+D₃，

For the preset P power coefficient of the heating stage of the third heating module,

the preset I power coefficient, Temp _ SubSum, of the heating stage in which the third heating module is positioned₃The temperature difference Temp _ Sub between the current temperature and the target temperature is less than 1 DEG C₃An accumulated value of (d);

the fourth heating module is used for adopting Power _ k₄Value heated, Power _ k₄＝P₄+I₄+D₄，

the preset I power coefficient, Temp _ SubSum, of the heating stage in which the third heating module is positioned₄The temperature difference Temp _ Sub when the difference between the current temperature and the target temperature is less than 0.25 DEG C₄The accumulated value of (1).

The technical scheme that this application provided's advantage lies in, adopts the heating tape winding parcel to clear up the cup body as system heating device to adopt bump and wrapping post mode to fix the heating tape in the cup outside of clearing up. The resistivity of the heating belt is low, the heating belt with more windings is densely wound on the outer surface of the digestion cup, the effective heating area is large, the reaction solution in the digestion cup is uniformly heated and has a good heating effect, the digestion cup is extremely in accordance with the temperature curve of the national standard laboratory, the oxidation rate of a sample substance is relatively stable, and the measured value has good stability and accuracy, so that the high-efficiency and accurate detection of water quality is realized, the phenomenon of breaking of the digestion cup due to nonuniform heating is avoided, and the stability, reliability and safety of the system are favorably improved; in addition, the power of heating the area is higher, need not to adopt the mode of preheating to preheat in advance, promotes water quality testing efficiency, has reduced and has cleared up cup temperature control.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the related art, the drawings required to be used in the description of the embodiments or the related art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a structural diagram of a specific embodiment of a potassium permanganate index analyzer according to an embodiment of the present invention;

fig. 2 is a structural diagram of another specific embodiment of the potassium permanganate index analyzer provided in the embodiment of the present invention;

fig. 3 is a top view structural diagram of the potassium permanganate index analyzer shown in fig. 2 according to an embodiment of the present invention;

FIG. 4 is a diagram illustrating a standard temperature curve and an actual temperature variation comparison curve of an instrument according to an embodiment of the present invention;

FIG. 5 is a block diagram of a hardware temperature control module according to an embodiment of the present invention;

fig. 6 is a structural diagram of a specific implementation of an emergency connection sub-module according to an embodiment of the present invention.

Detailed Description

In order that those skilled in the art will better understand the disclosure, the invention will be described in further detail with reference to the accompanying drawings and specific embodiments. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The terms "first," "second," "third," "fourth," and the like in the description and claims of this application and in the above-described drawings are used for distinguishing between different objects and not for describing a particular order. Furthermore, the terms "comprising" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements but may include other steps or elements not expressly listed.

Having described the technical solutions of the embodiments of the present invention, various non-limiting embodiments of the present application are described in detail below.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a potassium permanganate index analyzer according to an embodiment of the present invention, where the embodiment of the present invention includes the following:

potassium permanganate index analyzer 0 can include and resolve a cup body 1, heating module 2 and temperature controller 3. The heating module 2 is arranged on the outer side of the digestion cup body 1, and the temperature controller 3 is connected with the heating module 2.

The digestion cup body 1 can be any one of the digestion cup bodies in the prior art, and the digestion cup body is not limited in this application. Because heating module 2 sets up in clearing up 1 outsides of cup, transmits heat to inside reaction solution through clearing up cup 1, in view of the good heat transfer effect of quartzy material, clears up 1 material of cup and can adopt quartzy material, promotes whole reaction solution's heating effect.

In the embodiment of the present invention, the heating module 2 may include a heating tape 21, a plurality of bumps 22, and a winding post 23. In order to improve the heating uniformity, the heating belt 21 can be wound outside the digestion cup body 1 in an equally spaced and fitting manner, that is, the vertical distance between every two winding turns of the heating belt 21 is the same, and the heating belt 21 is tightly attached to the outside of the digestion cup body 1. Because the heating belt 21 is the strip structure that has certain width, thickness and weight, in order to prevent that the heating belt 21 from coming off from digesting the cup, or two adjacent winding circles because the circumstances such as the circuit short circuit that causes that the influence breaks away from original position coincide together or contact causes the heating homogeneity not good take place, need carry out stable, reliable fixed to heating belt 21.

It can be understood that each salient point 22 and each winding post 23 are arranged on the outer side of the digestion cup body 1 and are used for fixing or installing the heating belt 21, and the number of the salient points 22 is determined according to the length, the width and the fixing mode of the heating belt 21; the winding posts 23 include two, one of which is connected to the beginning of the heating tape 21 through a connection terminal, the other of which is connected to the end of the heating tape 21 through a connection terminal, and the other end of the winding post 23 is connected to a power supply, so that the heating tape 21 is connected to the power supply. The salient points 22 can be divided into two types according to the positions, the first type of salient points are positioned at the left side and the right side of the digestion cup body 1, the salient points at the same side are distributed at equal intervals, the second type of salient points are positioned below the initial winding circle and the ending winding circle of the heating belt, and the salient points at the same horizontal plane are symmetrically distributed at the front side and the rear side of the digestion cup body 1. For example, the digestion cup is a cylinder, the left side and the right side in the embodiment refer to the left side and the right side of the cross section of the cylinder, the front side and the rear side also refer to the front side and the rear side of the cross section of the cylinder, and the front side and the rear side can be determined according to the actual needs and use of a user, which is not limited in this application. It should be noted that if other protruding devices or devices are arranged outside the digestion cup body 1, for example, the temperature sensor 4 may be arranged half inside the digestion cup and half outside the digestion cup, and the position of the digestion cup is half of the volume of the reaction solution, and it is inevitable that the heating tape 21 will pass through the temperature sensor 4 during the winding process, the first type of bumps are distributed with equal spacing in this application scenario, and the distance between two bumps adjacent to the temperature sensor 4 is 2 times the distance between the rest bumps, that is, the distance between the bump and the temperature sensor 4 is the distance between the other bumps, as shown in fig. 2, for example. In this application scenario, since the distance between the two upper and lower windings of the heating belt 21 at the level of the temperature sensor 4 may be larger than the distance between the other windings, in the embodiment of the present invention, the distance between the two particular windings is default to be the same as the distance between the other windings.

In the present application, the temperature controller 3 may be configured to control the heating power of the heating module according to the real-time temperature of the reaction solution in the digestion cup and the standard temperature curve, so that the real-time temperature of the reaction solution is kept consistent with the corresponding target temperature on the standard temperature curve, as shown in fig. 4. The standard temperature curve can also be called a laboratory curve, or a laboratory temperature control curve, and the curve generation process is as follows: adding a water sample and a reagent into the conical flask, then placing the conical flask into a water bath kettle, and recording a function change curve of the solution temperature and the heating time of the conical flask in the whole process from the step of placing the conical flask into the water bath kettle to the step of finishing the boiling water bath, wherein the function change curve is a standard temperature curve. Each target temperature on the standard temperature curve was obtained: according to the national standard test scheme, the conical flask with the sample is placed in a water bath kettle for boiling water bath for 30min, a temperature sensor is positioned in the middle of the solution, numerical values are read every second, each numerical value is a target temperature, and the change of a plurality of target temperatures along with time is a standard temperature curve. Digestion cup reaction solution or digestion cup actual temperature can adopt a temperature sensor to read the digestion cup temperature every 1s in real time, the temperature sensor can be positioned in the middle of the reaction solution, automatically stores data, and transmits the data to a memory of a main control board of a potassium permanganate index analyzer 0. Optionally, the temperature controller 3 may be disposed in the main control board of the potassium permanganate index analyzer 0. The potassium permanganate index analyzer 0 adapts to a corresponding target temperature point on the standard temperature curve according to the initial temperature monitored by the temperature sensor at the initial heating time according to the standard temperature curve written in the main control board, the point on the curve is used as the initial temperature, the subsequent temperature can be compared with the target temperature for 1 time every 1s by a computer control program in the temperature controller 3, and the corresponding heating power is calculated through the temperature difference between the actual temperature of the digestion cup and the target temperature, so that the temperature control requirement is met, and the temperature curve is relatively flat.

It should be noted that, the heating effect may still be good when related technologies such as heating module 2 adopts the heater strip to clear up the cup and heat to the small capacity, but clear up the cup to the large capacity, for example the capacity is not less than 120ml clear up the cup, and the heating homogeneity is relatively poor, can't clear up each position of cup and carry out the even heating, and the homogeneity of the heating effect of cup is cleared up to the large capacity to this application technical scheme is more obvious, can realize that the even heating clears up the inside liquid of cup body. That is to say, the technical scheme of the application is suitable for the digestion cup with the capacity of not less than 120 ml.

According to the technical scheme provided by the embodiment of the invention, the digestion cup body is wrapped by the heating tape as a system heating device, and the heating tape is fixed on the outer side of the digestion cup in a salient point and winding column mode. The resistivity of the heating belt is low, the heating belt with more windings is densely wound on the outer surface of the digestion cup, the effective heating area is large, the reaction solution in the digestion cup is uniformly heated and has a good heating effect, the digestion cup is extremely in accordance with the temperature curve of the national standard laboratory, the oxidation rate of a sample substance is relatively stable, and the measured value has good stability and accuracy, so that the high-efficiency and accurate detection of water quality is realized, the phenomenon of breaking of the digestion cup due to nonuniform heating is avoided, and the stability, reliability and safety of the system are favorably improved; in addition, the power of heating the area is higher, need not to adopt the mode of preheating to preheat in advance, promotes water quality testing efficiency, has reduced and has cleared up cup temperature control.

In a preferred embodiment, the temperature controller 3 controls the heating power of the heating modules by means of a PID computer control program.

The PID computer control program is composed of a proportional unit P, an integral unit I and a differential unit D. In the negative feedback PID control, the output signal of the proportional control is proportional to the deviation of the temperature sensing element, and a fixed static difference is obtained between the result and the set value. When proportional control is added, the integral control can eliminate steady-state error, and the output signal can slowly rise along with time, which is equivalent to the cumulative effect of the input signal on the time. But may increase overshoot. In this case, the differential control is introduced to accelerate the response speed of the large inertia system and reduce the overshoot tendency, because the large inertia component (link) or the delay component has the effect of suppressing the error, and the change always lags behind the error change. By adjusting three different parameters, the adjustment process can be both smooth and rapid.

It will be appreciated that the PID computer control program, when it begins execution, needs to initialize the macro definition variables involved in the whole process to ensure that the macro definition variables in each measurement are adaptive. The macro defining variables include a current temperature and target temperature difference Temp _ Sub, a temperature difference sum accumulation Temp _ SubSum, an adaptive adjustment coefficient heatRef, and heating Power Power _ k, wherein Power _ k is the sum of PIDs and is maximum 1.0. After Power _ k is obtained, Power _ k may be converted into a PWM signal output to control the heating Power of the heating module 2. The PID computer control program carries out staged heating with different powers according to the relation between the target temperature and the actual temperature, and the specific steps can be as follows:

the first stage is as follows: and (4) an adaptive judging stage (suitable for the current temperature being 50% of the target temperature).

And judging the position of the current temperature in the standard temperature curve, and calculating the time required by the current temperature to reach 50% of the target temperature, wherein the self-adaptive judgment process is not limited to a certain stage, and each stage can self-adaptively judge to generate a heatRef variable.

And a second stage: straight line heating phase (applicable to current temperature at target temperature 50%).

For example, 90% full power heating may be used and the time required to reach 50% of the target temperature is calculated and compared to the time in the first stage and a determination is made as to whether to add or subtract or not to change the heating power.

And a third stage: and judging the position in the temperature curve table.

And inquiring the position of the current temperature in the standard temperature curve according to the target temperature of the digestion cup initial temperature corresponding to the standard temperature curve.

A fourth stage: PID heating (applicable to current temperature less than target temperature 85%).

P: p power coefficient + heatRef;

i: i power coefficient Temp _ Sub (accumulated when Temp _ Sub is less than 1.5 ℃);

d: d power coefficient Temp _ Sub (D power is maximum when Temp _ Sub is less than-3 ℃ and D power is 0 when it is greater than 3 ℃);

power _ k ═ P + I + D (converted to PWM output).

The fifth stage: PID heating (suitable for the current temperature is less than the target temperature minus 0.5 ℃).

P: p power coefficient + heatRef;

i: i power coefficient Temp _ Sub (accumulated when Temp _ Sub is less than 1 ℃);

d: d power coefficient Temp _ Sub (D power is maximum when Temp _ Sub is less than-2 ℃ and D power is 0 when it is greater than 2 ℃);

power _ k ═ P + I + D (converted to PWM output).

The sixth stage: PID heating (maintenance at target temperature stage).

P: p power coefficient + heatRef;

i: i power coefficient Temp _ Sub (accumulated when Temp _ Sub is less than 0.25 ℃);

d: d power coefficient Temp _ Sub (D power is maximum when Temp _ Sub is less than-0.5 ℃ and D power is 0 when it is greater than 0.5 ℃);

power _ k ═ P + I + D (converted to PWM output).

It should be noted that the P power coefficient, the I power coefficient, and the D power coefficient of each stage may be preset, and may be the same or different, and those skilled in the art may determine the P power coefficient, the I power coefficient, and the D power coefficient according to actual situations and their own experiences. P + I + D + heatRef is 1, and the heatRef can be controlled to a value of ± 10%.

Accordingly, in correspondence with the above-described staged heating, the temperature controller 3 may include:

the first heating module is used for heating by adopting first power and adjusting the first power by using a self-adaptive adjusting coefficient if the current temperature of the reaction solution is not more than 50% of the corresponding target temperature value on the standard temperature curve; the adaptive adjustment coefficient is generated according to theoretical time required by the current temperature value to rise to the target temperature value in the first preset power heating process and actual time required by the current temperature value to rise to the target temperature value in the first preset power heating process. The self-adaptive adjusting coefficient is automatically generated, and the first preset power is adjusted based on the self-adaptive condition coefficient, so that the final reaction solution temperature and the target temperature are close to the same or completely the same. Due to the use condition of the heating module 2, the actual heating time and the theoretical heating time are different, and the larger the time difference between the actual heating time and the theoretical heating time is, the more serious the aging degree of the heating module is.

And the second heating module is used for heating according to a second power value if the current temperature of the reaction solution is greater than 50% of the corresponding target temperature value on the standard temperature curve and is not greater than 85% of the target temperature value.

And the third heating module is used for heating according to a third power value if the current temperature of the reaction solution is more than 85% of the target temperature value and is not more than-0.5 ℃ of the target temperature value.

In this embodiment, the first power, the second power, the third power, and the fourth power may be preset by a person skilled in the art according to experience of the person in the art according to an actual application scenario, but for more accurate temperature control, the heating power of the corresponding stage may be generated by adaptive calculation according to a use state of the actual heating module 2, and specifically may include:

the first heating module is used for adopting Power _ k₁Value heated, Power _ k₁＝90％*P_max，P_maxIs the maximum heating power.

The preset P power coefficient of the heating stage of the second heating module is shown, and heatRef is a self-adaptive adjusting coefficient;

for the preset I power coefficient of the heating stage of the second heating module, Temp _ SubSum₂The temperature difference Temp _ Sub when the difference between the current temperature and the target temperature is less than 1.5 DEG C₂The accumulated value of (1).

The preset P power coefficient of the heating stage of the third heating module,

is a preset I power coefficient, Temp _ SubSum, of the heating stage in which the third heating module is positioned₃The temperature difference Temp _ Sub when the difference between the current temperature and the target temperature is less than 1 DEG C₃The accumulated value of (1).

is a preset I power coefficient, Temp _ SubSum, of the heating stage in which the third heating module is positioned₄The temperature difference Temp _ Sub when the difference between the current temperature and the target temperature is less than 0.25 DEG C₄The accumulated value of (1).

Wherein,

and

for example, it may be 60%.

As can be seen from the above, the PID computer control program is adopted to control the temperature control process of the digestion cup in strict accordance with the standard temperature curve in the temperature rise process. The instrument has good stability of measured data, avoids interfering the oxidation degree of the instrument to water quality, and has stable oxidation rate to the sample. The problems that in the related art, the heating curve amplitude is large and the oxidation rates of different samples at different moments are difficult to ensure consistency due to the fact that the heating is carried out with full power in the whole process are solved.

It will be appreciated that as the heating module 2 is used, its heating effect may be gradually reduced, or the heating effect may be significantly reduced due to a malfunction or the like. And the heating module of the manufacturer instrument on the market is only used for heating and cannot judge whether the heating module is qualified or not or the aging degree through the heating process. Based on this, the present application may also include a heating module operating condition monitor connected to the temperature controller 3. The heating module running state monitor is used for detecting the using state of the heating module according to the self-adaptive adjusting coefficients automatically generated by the temperature controller at different moments in the using process of the heating module. In particular embodiments, the heating module operating condition monitor may include:

Therefore, when the instrument is tested by a single machine when leaving a factory, the embodiment of the invention can judge whether the heating module meets the factory standard or not and whether the power of the heating module meets the requirement or not according to the value of heatRef. In addition, the upper computer of the potassium permanganate index analyzer 0 records the heatRef value monitored in each measurement, a function curve of time and the heatRef value can be drawn, and the time is taken as an abscissa and corresponds to the measured heatRef value recorded by the upper computer of the potassium permanganate index analyzer. The state of the heating module can be judged according to the trend of the curve, and an upper limit and a lower limit are set through monitoring the value of heatRef. If the current time exceeds the set limit value, the module is prompted to age and needs to be operated, maintained and replaced.

As can be understood, the length of the heating belt has great influence on the heating power of the whole digestion cup, and the heating power can be effectively controlled by selecting the material and the length of the heating belt. The length L of the heating belt can be determined according to the heating power (P ═ U)²and/R, R ═ L × ρ), the resistivity ρ of the heating zone, and the operating voltage U of the heating zone.

Optionally, the heating effect and the fixing effect of the digestion cup are considered, the length of the heating belt 2 can be set to 1.4m, the width can be set to 3mm, and the thickness can be set to 0.25 mm. The contact specific surface area is large, the resistance value is small, the contact of the outer surface of the digestion cup can be better achieved, the winding mode is convenient, the cost performance is high, and a good temperature rising effect is achieved. The material can adopt cadmium-nickel alloy, namely a heating belt made of cadmium-nickel, the material is soft, the material can be well attached to the outer wall of the digestion cup without gaps, and the material does not need to be filled between the heater and the reaction cup, so that the heat conductivity coefficient between the heater and the reaction cup is improved. This way, the breakage of the glass can be greatly reduced.

After the length of the heating belt is calculated, the distance between the first type of salient points positioned on the same side can be calculated according to the length and the width of the heating belt, the height of the liquid level in the cup body of the digestion cup and the diameter of the cup body. In one embodiment, when the heating tape has a length of 1.4m, a width of 3mm and a thickness of 0.25mm, the interval between the first type bumps on the same side can be set to 4.5 mm.

It can be understood that the potassium permanganate index analyzer 0 can have software faults, for example, the main control panel or the circuit is dead or abnormal in heating, the heating belt 21 cannot disconnect the circuit, the heating is carried out for a long time, and the digestion cup is abnormally heated, so that the reagent is splashed or the digestion cup is broken, and the stable and reliable operation of the potassium permanganate index analyzer 0 is not facilitated. Based on this, potassium permanganate index analyzer 0 can also include the hardware temperature control module who establishes ties with heating module 2, and this module is used for when dispelling a cup body temperature and surpassing the temperature threshold value, disconnection heating module and power between the connecting circuit to make heating module stop to the reaction solution heating.

In one embodiment, referring to fig. 5, the hardware temperature control module may include a first connection terminal 51, a fuse 52, and a second connection terminal 53; one end of the fuse is connected with one end of the heating belt through the first wiring terminal, and the other end of the fuse is connected with the winding post through the second wiring terminal. It should be noted here that, since the terminal of the heating tape 21 is connected to the corresponding winding post through the connection terminal, if the hardware temperature control module is connected in series to the terminal of the heating tape 21, the terminal of the heating tape 21 is connected to the first connection terminal 51, and the winding post 23 is connected to the second connection terminal 53. If the fuse uses the mode of hanging, or temperature protection system is insensitive, and unable fusing, or it is great to receive the influence of 0 inside temperature of potassium permanganate index analysis appearance, and hardware temperature control module very easily touches the execution by mistake, leads to 0 measuring value error production of potassium permanganate index analysis appearance and security not high, so fuse 52 can paste the wall and set up in digesting the cup body outside. The fuse may be, for example, an alloy-type thermal fuse, and the operating temperature of the alloy-type thermal fuse is equal to the temperature threshold. After the thermal fuse is fused, even if the ambient temperature is reduced, the thermal fuse can not be conducted any more. The temperature fuse comprises an action temperature and a working temperature, the working temperature is lower than the temperature controlled by the digestion cup, namely a temperature threshold value, and the action temperature refers to the temperature for fusing the fuse.

According to the method, the temperature protection wire is connected in series in the heating system, the digestion cup is protected in a hardware mode, the digestion cup is not influenced by software and a main control board, and the condition of the heating system is monitored constantly. The temperature protection wire adopts a mode of pasting and digesting the cup wall, feels and digests the cup temperature, and is a non-suspended temperature fuse. The method has strong temperature sensitivity and is not easily influenced by the internal environment temperature of the instrument.

In another embodiment, after the hardware temperature control module is triggered to execute, that is, the heating module 2 is not connected with the power supply, the digestion cup is not in a heating state, but if the digestion cup needs to be heated in a special situation, the heating function needs to be temporarily recovered. Based on this, hardware temperature control module still can include the emergent submodule of connecting, and the emergent submodule of connecting is used for dispelling the temperature of cup body and surpassing the temperature threshold, and the circuit between intercommunication heating module and power to make heating module continue to heat reaction solution. Referring to fig. 6, the emergency connection sub-module may include a first conductive wire and a second conductive wire, wherein one end of the first conductive wire is connected to the first connection terminal, and a first connection terminal is disposed at a tail end of the other end of the first conductive wire; one end of the second wire is connected with the second wiring terminal, and the tail end of the other end of the second wire is provided with a second connecting end; when the second connecting end is connected with the second connecting end in an inserting mode, the circuit between the heating module and the power supply is communicated. For example, one copper wire 54 may be provided on each of the two terminals, and the two copper wires may be directly connected when the temporary heating function needs to be recovered.

It will be appreciated that the fuse is important to the protection of the entire system, and that the temperature values experienced by the fuse are related to their height or adherence position outside the digestion cup. The fuse is mainly influenced by the temperature of the heating belt heating digestion cup body, the temperature radiated in the heating process of the heating belt and the temperature transmitted to the fuse by the heating belt through a lead. The wall-attached position of the fuse needs to meet the following requirements: when the digestion cup normally controls the temperature to 95 ℃, the temperature sensed by the fuse does not exceed the normal working temperature of the fuse. When the digestion cup is heated abnormally in an empty cup or in a water state, the temperature sensed by the fuse exceeds the action temperature of the fuse, and the purpose of quick fusing is achieved. In conclusion, the target adherence position or the target height of the fuse at the outer side of the digestion cup body can be determined according to the position sensing temperature value, the work limitation condition and the optimal position point selection condition of the fuse at the disposal position with different height at the outer side of the digestion cup body.

The position sensing temperature value is the sum of the temperature value of the heating belt heating digestion cup body, the radiation temperature value in the heating process of the heating belt and the temperature value transmitted to the fuse by the heating belt through a lead; the working limiting conditions are that the fuse position sensing temperature value is less than the working temperature of the fuse (such as 100 ℃) in the normal temperature control process, the fuse position sensing temperature value is greater than the fuse action temperature in the abnormal heating process of the hollow cup, and the fuse position sensing temperature value is greater than the fuse action temperature (such as 138 ℃) in the abnormal heating process. The optimal position point selection condition is that the time value of the time required from the start of abnormal heating to the fuse blowing at the target adhesion position is shortest and not more than a first time threshold value. That is, the time required from the start of abnormal heating to the fusing of the fuse is calculated at each adhesion position, then the minimum value of the required time is selected from the calculated values, if the value is not more than the first time threshold value, the adhesion position corresponding to the value is taken as the height position or the target adhesion position of the fuse located outside the digestion cup body, and if the value is more than the first time threshold value, the parameter selection or the winding mode of the heating tape is wrong, the parameter of the heating tape and the winding mode need to be determined again, the parameter of the heating tape is such as length, material, width and the like, and the winding mode comprises the spacing distance of each winding circle of the heating tape and the like. The first time threshold may be selected according to an actual application scenario, for example, 10min, which is not limited in this application.

The position sensing temperature value can be determined according to a prestored temperature-time curve graph; the temperature-time profile comprises a first curve, a second curve, and a third curve; the first curve is generated according to the temperature of the heating zone for heating the digestion cup in the normal temperature control process of the digestion cup, the empty cup full-power heating process and the full-power heating process of the water in the cup body along with the change relation of time; the second curve is generated according to the change relation of the radiation temperature in the heating process of the heating belt along with the time in the normal temperature control process of the digestion cup, the full-power heating process of the empty cup and the full-power heating process of the water in the cup body; and the third curve is generated according to the change relation of the temperature transmitted to the fuse by the heating belt through a wire along with time in the normal temperature control process of the digestion cup, the full-power heating process of the empty cup and the full-power heating process of water in the cup body. During the process of drawing each curve, corresponding temperature values can be acquired by an external temperature sensor, for example, every 1 s.

After the position of the fuse is calculated by the method, the fuse can be fixed at the position through the winding post. For example, the fuse is a soluble alloy type temperature fuse, one end of the soluble alloy type temperature fuse is connected with the first terminal through a third winding post, and the other end of the soluble alloy type temperature fuse is connected with the second terminal through a fourth winding post; the third winding post and the fourth winding post are used for fixing the soluble alloy type temperature fuse at a target height; in one embodiment, the target height of the fusible alloy type thermal fuse may be 16.5cm from the bottom of the digestion cup and 0.5cm from the nearest winding turn of the heating belt to the top of the digestion cup.

As a preferred embodiment, the potassium permanganate index analyzer 0 may further include a heat radiation fan located outside the digestion cup body 1. The rotation speed of the cooling fan can be increased along with the increase of the temperature of the digestion cup body, and the rotation speed can be automatically adjusted according to the temperature of the digestion cup body and the preset fan rotation speed adjusting coefficient. After the heating belt 21 stops heating, the surface of the heating belt 21 is cooled to the room temperature very quickly by the heat radiation fan, and the temperature control capability is improved.

Optionally, the potassium permanganate index analyzer 0 may further include a stirrer located at the bottom end inside the digestion cup body 1, the rotation speed of the stirrer may be increased along with the increase of the volume of the reaction solution, and the rotation speed may be automatically adjusted according to the volume of the reaction solution and a preset stirring rotation speed adjustment coefficient. The purpose of uniform reaction and dissolution temperature is achieved by arranging the stirrer with adjustable rotating speed and controlling the rotating speed of the stirring motor according to the liquid level volume.

In addition, the potassium permanganate index analyzer 0 sampling system is in fault or abnormal operation, if full-power heating is still adopted, the phenomenon that the digestion cup is empty and burnt can be caused, the service life of the digestion cup is shortened, and even the digestion cup is broken, so that potential safety hazards are brought. In view of this, the potassium permanganate index analyzer 0 may further include a liquid level alarm system disposed on the sample injection pipeline, and configured to alarm and prompt when the monitored volume of the solution inside the digestion cup body is lower than a preset volume threshold value within a preset time period. Optionally, the liquid level alarm system may include a photoelectric isolator and a voice alarm, and the photoelectric isolator is connected to the voice alarm. And a photoelectric isolator is arranged on the sample injection pipeline, and the state of the pipeline is judged by constantly monitoring the voltage value of the receiving end. When the pipeline enters a water state from a water-free state, the potential can jump, and the second state change occurs in the process of extracting the sample, so that the condition that water is lacking or air bubbles enter the pipeline can be judged, and the sample injection abnormity can be found in time.

Finally, in order to make the technical solutions of the present invention more clear to those skilled in the art, the present application also provides a specific example of water quality detection based on the potassium permanganate index analyzer shown in fig. 2 and fig. 3, which may include the following:

the water quality detection process of the potassium permanganate index analyzer 1 is as follows: the sample is firstly determined by the quantitative cup, and then successfully enters the digestion cup through the sample introduction pipeline by monitoring of the liquid level alarm system. Then, adding sulfuric acid and potassium permanganate; the potassium permanganate index analyzer 1 can read the temperature of the reaction solution in the digestion cup 1 time every 1s by adopting a temperature sensor which is integrally formed with the digestion cup and is arranged in the middle of the reaction solution according to a standard temperature curve written in a main control board and the actual temperature of the reaction solution in the digestion cup, and compares the actual temperature of the digestion cup with the target temperature through a PID control program, so that the real-time temperature of the reaction solution is kept consistent with the corresponding target temperature on the standard temperature curve, namely, the temperature is gradually increased from the normal temperature to 94.7 ℃ after about 5min, and then the temperature is continuously controlled at 94.7 ℃. In the heating process, the hardware temperature control module is connected in series in the heating module, and the digestion cup is protected by adopting a hardware mode and is not influenced by software and a main control board, so that the condition of the heating system is monitored constantly. When the heating system is abnormal, the whole heating module is disconnected. And (3) continuously heating for 30min according to the national standard test requirement, then adding a sodium oxalate reagent, reacting for a period of time, carrying out back titration by using potassium permanganate, and calculating the permanganate index of the water quality by titrating the volume of the consumed potassium permanganate to realize the monitoring of the water quality.

Therefore, the embodiment of the invention is beneficial to realizing efficient and accurate water quality detection.

The embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same or similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.

Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in Random Access Memory (RAM), memory, Read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

The potassium permanganate index analyzer provided by the invention is described in detail above. The principles and embodiments of the present invention are explained herein using specific examples, which are presented only to assist in understanding the method and its core concepts. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

Claims

1. The potassium permanganate index analyzer comprises a digestion cup body, and is characterized by also comprising a heating module and a temperature controller, wherein the heating module is arranged on the outer side of the digestion cup body;

2. The potassium permanganate index analyzer according to claim 1, further comprising a hardware temperature control module connected in series with the heating module, and configured to disconnect a connection circuit between the heating module and a power supply when the temperature of the digestion cup body exceeds a temperature threshold value, so that the heating module stops heating the reaction solution;

the hardware temperature control module comprises a first wiring terminal, a fuse and a second wiring terminal; one end of the fuse is connected with one end of the heating belt through the first wiring terminal, the other end of the fuse is connected with the winding post through the second wiring terminal, and the fuse is arranged on the outer side of the digestion cup body in an adherence mode.

3. The potassium permanganate index analyzer according to claim 2, wherein the target adherence position of the fuse at the outer side of the digestion cup body is determined according to position sensing temperature values, working limitation conditions and optimal position point selection conditions of the fuse at different height positions at the outer side of the digestion cup body;

4. The potassium permanganate index analyzer of claim 3, wherein the fuse is a soluble alloy type temperature fuse, and the operating temperature of the soluble alloy type temperature fuse is the same as the temperature threshold;

5. The potassium permanganate index analyzer of claim 2, wherein the hardware temperature control module further comprises an emergency connection sub-module, and the emergency connection sub-module is used for communicating a circuit between the heating module and a power supply when the temperature of the digestion cup body exceeds a temperature threshold value, so that the heating module continues to heat the reaction solution;

6. The potassium permanganate index analyzer according to claim 1, further comprising a liquid level alarm system disposed on the sample introduction pipeline, for giving an alarm prompt when the volume of the solution inside the digestion cup body is monitored to be lower than a preset volume threshold value within a preset time period;

7. The potassium permanganate index analyzer according to claim 1, wherein the length of the heating zone is calculated from the heating power, the resistivity of the heating zone and the operating voltage of the heating zone; the heating belt is made of cadmium-nickel materials; the heating belt has a length of 1.4m, a width of 3mm and a thickness of 0.25 mm.

8. The potassium permanganate index analyzer according to claim 7, wherein the distance between the first type of bumps on the same side is calculated according to the length and width of the heating belt, the height of the liquid level in the cup body of the digestion cup and the diameter of the cup body; the spacing between the bumps of the first type, which are located on the same side, is 4.5 mm.

9. The potassium permanganate index analyzer of claim 8, further comprising a stirrer positioned at the bottom end inside the digestion cup body, wherein the rotation speed of the stirrer is increased along with the increase of the volume of the reaction solution, and the rotation speed is automatically adjusted according to the volume of the reaction solution and a preset stirring rotation speed adjusting coefficient.

10. The potassium permanganate index analyzer of claim 9, further comprising a heat sink fan located outside the digestion cup body; the rotation speed of the heat radiation fan is increased along with the increase of the temperature of the digestion cup body, and the rotation speed is automatically adjusted according to the temperature of the digestion cup body and a preset fan rotation speed adjusting coefficient.

11. The potassium permanganate index analyzer of any one of claims 1 to 10, wherein the temperature controller is configured to control the heating temperature of the digestion cup when executing a PID computer control program stored in memory; the temperature controller includes:

12. The potassium permanganate index analyzer of claim 11, further comprising a heating module operating condition monitor connected to the temperature controller; the heating module running state monitor is used for detecting the using state of the heating module according to self-adaptive adjusting coefficients automatically generated by the temperature controller at different moments in the using process of the heating module; the heating module operating condition monitor comprises:

13. The potassium permanganate index analyzer of claim 12,

the first heating module is used for adopting Power _ k₁Value heated, Power _ k₁＝90％*P_max，P_maxIs the maximum heating power;

the preset I power coefficient, Temp _ SubSum, of the heating stage in which the third heating module is positioned₃The temperature difference between the current temperature and the target temperature is less than 1 DEG CTemp_Sub₃An accumulated value of (d);