Device and method for measuring ammonia nitrogen in water

Abstract

The invention belongs to the technical field of ammonia nitrogen detection, and discloses a water quality ammonia nitrogen determination device and method.The device comprises a stirring barrel and an ammonia gas sensitive electrode movably arranged in the stirring barrel, the stirring barrel is provided with a heat exchange cavity defined by an inner wall and an outer wall, the device further comprises a cooling assembly, and the cooling assembly is used for conveying a cooling working medium into the heat exchange cavity; the through groove is formed in the inner wall and the outer wall, and the ammonia gas sensitive electrode penetrates through the through groove; the lifting assembly comprises a sliding block and a pull wire connected with the sliding block, one end of the sliding block is arranged in the heat exchange cavity, the sliding block is connected with a reset piece, and the free end of the pull wire is connected with the ammonia gas sensitive electrode; according to the scheme, the ammonia gas sensitive electrode is obtained by changing the flow speed and size of the working medium, and the potential value measured by the ammonia gas sensitive electrode is prevented from being influenced by temperature change; the problem that in the prior art, stirring is adopted, so that the measuring potential of the ammonia gas sensitive electrode is not accurate is solved, and the method is suitable for measuring the ammonia nitrogen content through an ammonia gas sensitive electrode method.

Description

Technical Field

[0001] The present invention belongs to the technical field of ammonia nitrogen detection, and specifically relates to a device and method for determining ammonia nitrogen in water quality. Background Art

[0002] Referring to the existing disclosure (announcement) number CN105738452A, a method and device for detecting ammonia nitrogen using a fully solid-state ammonia nitrogen sensor, according to the chemical characteristics and physical properties of ammonia nitrogen, there are three main analytical methods for detecting ammonia nitrogen content in the world, namely spectrophotometry, Kjeldahl nitrogen determination and ammonia sensitive electrode method. Spectrophotometry has the disadvantages of more sampling and being easily disturbed by the surrounding environment. The Kjeldahl nitrogen determination method takes a long time and requires complicated steps. The biggest advantage of the ammonia sensitive electrode method is that the sampling amount is small, the operation is simple, the speed is fast, the cost is low, it is not affected by colorimetric interference, and it is particularly suitable for on-site detection.

[0003] Referring to the ammonia nitrogen detection equipment with the existing publication (announcement) number CN116413315A, the principle of the ammonia sensitive electrode method is as follows: the ammonia sensitive electrode is a composite electrode with a pH glass electrode as the indicator electrode and a silver-silver chloride electrode as the reference electrode. This electrode is placed in pairs in a plastic sleeve filled with ammonium chloride liquid. A hydrophobic semi-permeable film is installed at the end of the tube close to the sensitive membrane of the indicator electrode to separate the internal electrolyte from the external test solution. There is a very thin film between the semi-permeable membrane and the pH glass electrode. When a strong alkaline solution is added to the water sample to raise the pH to above 11, the ammonium salt is converted into ammonia, and the generated ammonia passes through the semi-permeable membrane due to diffusion (water and other ions cannot pass through). The NH4 + =NH3+H + The reaction moves to the left, causing the hydrogen ion concentration to change, which is measured by the pH glass electrode. Under constant ionic strength, the measured electromotive force and the logarithm of the ammonia nitrogen concentration in the water sample have a certain linear relationship. Therefore, the ammonia nitrogen content in the sample can be determined from the measured potential value.

[0004] Referring to the existing disclosure (announcement) number CN103512932A, the ammonia nitrogen detection method and device based on electrodialysis ion transformation, in the electrodialysis ammonia nitrogen detection, it is necessary to ensure that the pH value of the solution after mixing is higher than 11 to meet the alkalization demand, and when the water sample to be tested is mixed with the strongly alkaline electrolyzed water, it is generally necessary to use a stirrer for stirring, mainly to break the local concentration gradient in the water sample, ensure uniform mixing, and accelerate the acid-base reaction rate to reach the required pH value. However, when the acidic water sample to be tested is stirred and mixed with alkaline electrolyzed water, an exothermic neutralization reaction will occur. This is because acid-base neutralization is an exothermic process, and the hydrogen ions (H+) in the acid are combined with the hydroxide ions (OH-) in the alkali to generate water, while releasing heat, causing the temperature of the mixed solution to rise. And the high temperature will promote the volatilization of ammonia nitrogen, increase the concentration of ammonia in the solution, thereby affecting the measurement potential of the ammonia sensitive electrode, so the ammonia sensitive electrode is greatly affected by the ambient temperature, and drift is prone to occur, resulting in the measurement voltage being difficult to stabilize (see CN110108769A). At the same time, when the water body is stirred by an existing stirring device (such as a stirring rod), the rotation of the stirring rod will generate eddy currents in the water body. Although the eddy currents help to mix the water sample to be tested with the alkaline solution, the stirring process will also cause air to be drawn into the liquid to form bubbles. Bubbles are easy to adhere to the boundary between the semipermeable membrane and the liquid, resulting in deviations in the electrode measurement potential (see CN106645343A). In addition, the generation and rupture of bubbles may cause local turbulence and solution flow, which will also interfere with the measurement accuracy of the electrode. Summary of the invention

[0005] The purpose of this scheme is to provide a device for determining ammonia nitrogen in water quality to solve the problem of inaccurate potential measurement of ammonia sensitive electrodes caused by stirring.

[0006] In order to achieve the above-mentioned purpose, the present invention provides a water quality ammonia nitrogen determination device, comprising a mixing drum and an ammonia sensitive electrode movably arranged in the mixing drum, wherein the mixing drum is provided with a heat exchange cavity formed by an inner wall and an outer wall, and further comprising:

[0007] A cooling component, which is used to transport cooling medium into the heat exchange cavity;

[0008] A through groove, the through groove is formed on the inner wall and the outer wall, and the ammonia sensitive electrode passes through the through groove;

[0009] A lifting component includes a slider and a traction line connected to the slider, one end of the slider is arranged in the heat exchange cavity, the slider is connected to a reset piece, and the free end of the traction line is connected to the ammonia sensitive electrode.

[0010] The principle of this scheme is: by controlling the flow rate of the cooling medium delivered by the cooling component, when the flow rate is large, the medium will push the slider to move to the maximum stroke, and the slider will pull the traction line to pull the ammonia sensitive electrode out of the water sample. When the flow rate decreases, the slider is reset under the drive of the reset component, so that the ammonia sensitive electrode is reinserted into the water sample.

[0011] The effects of this solution are as follows: (1) By setting a cooling component and a heat exchange cavity in the mixing drum, the temperature of the water sample can be controlled. When the pH value of the water sample is lower than 11, alkali solution needs to be added to the water sample to adjust the pH value, and the alkali solution needs to be stirred and mixed after being added, and the acid-base reaction releases heat. By increasing the flow rate of the cooling medium, the flow rate of the medium in the heat exchange cavity is faster, thereby taking away the heat in the mixing drum faster. At the same time, the ammonia sensitive electrode is pulled out of the water surface by increasing the flow rate of the medium, avoiding the problem of inaccurate electrode potential value measurement caused by uneven temperature and solution mixing during the acid-base mixing process. Furthermore, when the acid and base are mixed, due to the rapid change in the pH value of the water sample and the uneven acid-base mixing, if the electrode is always placed in the water at this time, it will also affect its measured potential value. Therefore, it is also necessary to remove the ammonia sensitive electrode from the water sample at this stage. (2) After the pH value is adjusted to greater than 11, the acid-base reaction has been completed and the water sample temperature has decreased under the action of the cooling medium. At this time, it is necessary to reduce the flow rate of the medium to avoid the temperature being too low to affect the measurement data of the ammonia sensitive electrode. Therefore, when the working fluid flow rate is reduced, the ammonia sensitive electrode is reinserted into the water sample to continue measuring it.

[0012] Furthermore, the lifting assembly also includes a gear and a fixed pulley, the slider is fixedly connected to a rack, the rack is meshed with the gear, the gear is coaxially connected to a winding roller, one end of the traction line passes around the fixed pulley and is fixedly connected to the winding roller; the reset member is a spring, one end of the spring is connected to the slider, and the other end is connected to the outer wall.

[0013] The principle and effect of this scheme are: (1) When the working fluid flow rate increases, the movement of the slider drives the rack to move, and the rack drives the gear to rotate, so that the winding roller rotates to store the traction line, thereby lifting the ammonia sensitive electrode. When the working fluid flow rate decreases, the slider and the rack are reset under the drive of the spring, thereby releasing the traction line and reinserting the ammonia sensitive electrode into the water sample. (2) Compared with the method of directly pulling the ammonia sensitive electrode through the slider, this scheme can make the storage and release of the traction line of the ammonia sensitive electrode smoother during the lifting and lowering process through the transmission of the gear, rack and fixed pulley, making the lifting and lowering of the ammonia sensitive electrode smoother.

[0014] Furthermore, a touch switch is provided on the outer wall, and the touch switch is electrically connected to the ammonia sensitive electrode. When the slider moves away from the touch switch, the ammonia sensitive electrode is powered off.

[0015] The principle and effect of this solution are as follows: since the ammonia sensitive electrode is always in a powered state in the water sample, when the electrode is away from the water sample and exposed to the air, it does not need to be powered on for detection at this stage. Therefore, when the slider is away from the touch switch, the ammonia sensitive electrode is powered off. When the slider is reset and contacts the touch switch, the ammonia sensitive electrode has been reinserted into the water sample and can be powered on.

[0016] Furthermore, the cooling component includes a first water wheel disposed in the heat exchange cavity, one end of the first water wheel is fixedly connected to the inner wall, and the other end is rotatably connected to the outer wall.

[0017] The principle and effect of this scheme are as follows: (1) The first water wheel rotates under the action of the cooling medium flow, thereby driving the inner wall of the mixing drum to rotate, and then stirring the water sample in the mixing drum. (2) In the stage of adding alkali solution to adjust the pH, the water temperature rises due to the heat release of the acid-base reaction. At this time, the water sample needs to be quickly stirred to promote rapid mixing and heat dissipation. By increasing the flow rate of the cooling medium, the medium can take away heat faster, and the increase in flow rate drives the first water wheel to rotate faster, so that the water sample stirring speed is faster, which promotes rapid mixing of the water sample and the alkali solution and heat dissipation of the water sample. In addition, after the pH is adjusted to greater than 11, constant temperature is required, and there is no need to stir and dissipate the water sample quickly. At this time, the rotation speed of the water wheel is adjusted by reducing the flow rate of the working medium to reduce the stirring intensity. (3) This scheme achieves stirring through the first water wheel and the inner wall. Compared with the prior art using an additional stirring device (such as a stirring rod), it can reduce the generation of eddy currents and bubbles caused by the stirring rod directly contacting the water sample rotation, thereby avoiding the interference of bubbles on the measurement accuracy of the ammonia sensitive electrode.

[0018] Furthermore, the heat exchange cavity is a heat exchange cavity with a spiral structure, and a water outlet hole is opened on the rotating shaft of the first water wheel; the cooling component also includes a water inlet pipe and a manual valve arranged on the water inlet pipe, and the water outlet end of the water inlet pipe is arranged in the heat exchange cavity; the water outlet hole is connected to the water outlet pipe through a rotating joint, and the water outlet pipe and the water inlet pipe are connected through a circulating pump.

[0019] The principle and effect of this scheme are as follows: (1) The water inlet pipe transports the cooling medium into the heat exchange cavity, and the medium flows along the spiral structure of the heat exchange cavity, thereby covering the inner wall to maintain constant temperature and cool the water sample, and the medium flows out through the water outlet hole, flows to the water inlet pipe through the water outlet pipe and the circulation pump, and realizes the recycling of the cooling medium. (2) This scheme opens the water outlet hole on the rotating shaft of the first water wheel, which can achieve better cooling and constant temperature effect compared with the prior art that opens the water outlet hole on the outer wall. Specifically, since the inner wall of the mixing drum is in a rotating state and the rotating shaft of the first water wheel is at the center of rotation, the medium that first enters the heat exchange cavity will move away from the water outlet hole of the first water wheel due to the centrifugal force generated by the rotation of the inner wall. Only when the heat exchange cavity is full of the medium can the medium flow out from the water outlet hole under the pressure of the circulation pump. If the water outlet is opened at other positions, the working fluid will not fill the heat exchange cavity before flowing out, so the working fluid cannot completely cover the inner wall of the mixing drum, resulting in a poor cooling and constant temperature effect.

[0020] Furthermore, it also includes a second water wheel, which is arranged in the through groove, and the two ends of the second water wheel are rotatably connected to the inner wall and the outer wall respectively. The second water wheel is a through hole structure, and a brush is arranged inside the through hole.

[0021] The principle and effect of this scheme are as follows: (1) Since the salt content in the water sample is high and the ammonia sensitive electrode is immersed in the water sample, the charge on the electrode surface will attract these ions and cause them to gather on the electrode surface. Over time, these salt substances will crystallize and scale on the electrode surface, thereby affecting the potential value measured by the electrode. At the same time, due to the rotation of the stirring drum, bubbles in the water sample will inevitably adhere to the electrode surface, which will also affect the measurement of the electrode. (2) In this scheme, the second water wheel rotates under the action of the flow of the cooling medium. When the ammonia sensitive electrode is lifted to the through hole in the second water wheel, the second water wheel drives the brush to rotate to clean the salt crystals and bubbles on the outer wall of the electrode.

[0022] Furthermore, it also includes an alkali adding component, which includes a pH meter arranged in the mixing drum and a first box body arranged on the mixing drum, the first box body is connected to an alkali adding pipeline, the end of the alkali adding pipeline is arranged in the mixing drum, a piston is arranged in the first box body, and it also includes a cylinder, the piston rod of the cylinder is connected to the piston, the pH meter is electrically connected to a controller, and the controller is electrically connected to the cylinder; a limit groove is provided on the handle of the manual valve, and a bolt is provided on the piston rod of the cylinder, and one end of the bolt is slidably arranged in the limit groove.

[0023] The principle and effect of this scheme are as follows: (1) The pH value in the water sample is measured by a pH meter. When the pH value is lower than 11, the piston rod of the cylinder is controlled by a controller to extend to squeeze the alkali solution in the first box into the mixing drum. At the same time, the extension of the piston rod will drive the bolt to move to the maximum stroke, thereby turning the handle of the manual valve to increase the flow rate of the working fluid. When the pH meter detects that the pH value of the water sample is greater than 11, the controller controls the piston rod of the cylinder to retract and reversely rotate the manual valve to reduce the flow rate of the working fluid. (2) Since the temperature change of the water sample is mainly due to the heat release of the acid-base reaction between the water sample and the alkali solution, the temperature will only change dramatically when the alkali solution is added. By adding the necessary operation of adjusting the pH value by adding alkali heat to link the opening and closing degree of the manual valve, the flow rate of the cooling working fluid can be synchronously adjusted to achieve stirring and heat dissipation of the water sample in the mixing drum and the lifting and lowering of the ammonia sensitive electrode. (3) Compared with the prior art, which uses multiple control elements to control each operation individually, it reduces the need for multiple independent control elements and reduces the complexity of the system.

[0024] Furthermore, the alkali adding assembly also includes a second box body, in which alkali solution is arranged, and the second box body is connected with the first box body through an alkali delivery pipeline; a one-way valve is arranged on the alkali delivery pipeline.

[0025] The principle and effect of this solution are as follows: (1) When the piston rod of the cylinder is retracted, there is no alkali solution in the first box. The piston in the first box is moved by the retraction of the piston rod, forming a negative pressure in the first box, and the alkali solution pre-stored in the second box is pumped into the first box. (2) A one-way valve is provided to prevent the alkali solution in the first box from flowing into the second box when it is squeezed.

[0026] A method for determining ammonia nitrogen in water quality, including using a device for determining ammonia nitrogen in water quality, including the following steps:

[0027] Step S10: preheating, placing the mixing drum 1 on a support, heating it to 38° C. in a constant temperature water bath, and keeping the temperature constant for 5 minutes;

[0028] Step S20: taking samples, respectively taking 10 mL of ammonium standard solutions with concentrations of 0.1 mg / L, 1 mg / L, 10 mg / L, and 100 mg / L into the mixing drum 1;

[0029] Step S30: electrolysis, slowly inserting the ammonia sensitive electrode 2 into the stirring drum 1, so that the semipermeable membrane of the ammonia sensitive electrode 2 is completely immersed in the water sample, and then adding 1 mL of sodium hydroxide-Na2-EDTA solution;

[0030] Step S40: measuring, during the stirring process of the mixing drum 1, observing the potential value measured by the ammonia sensitive electrode 2, and recording the reading when the potential value changes by no more than 1 mV within 1 minute;

[0031] Step S50: Determine, by recording the readings, select three or four standard points, and then draw a calibration curve of E-logc on a semi-logarithmic coordinate line.

[0032] Furthermore, in the step S30, the following steps are specifically included:

[0033] Step S31: When the pH meter detects that the pH value of the water sample is lower than 11, the controller controls the piston rod of the cylinder 64 to extend and squeeze the alkali solution in the first box 61 into the mixing drum 1 until the pH value of the water sample is not less than 11; then the controller controls the piston rod of the cylinder 64 to retract and pump the alkali solution in the second box 65 into the first box 61;

[0034] Step S32: When the piston rod of the cylinder 64 is extended, the handle of the manual valve 33 is driven to rotate, thereby increasing the flow rate of the cooling medium to make the mixing drum 1 rotate faster, and pushing the slider 41 to move to the maximum stroke to extract the ammonia sensitive electrode 2 out of the water sample; when the piston rod of the cylinder 64 is retracted, the handle of the handle valve 33 is driven to rotate in the opposite direction, thereby reducing the flow rate of the cooling medium to make the mixing drum 1 rotate slower, and the slider 41 is reset to insert the ammonia sensitive electrode 2 into the water sample;

[0035] Step S33: cleaning the ammonia sensitive electrode 2 after entering the second water wheel 5 . BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The structure of a water quality ammonia nitrogen determination device of the present invention is shown in FIG. Figure 1 ;

[0037] Figure 2 for Figure 1 Magnified view at A in the middle;

[0038] Figure 3 The structure of a water quality ammonia nitrogen determination device of the present invention is shown in FIG. Figure 2 ;

[0039] Figure 4 It is the ammonia nitrogen standard curve diagram of the present invention.

[0040] The figure marks in the drawings of the specification include: mixing drum 1, inner wall 11, outer wall 12, heat exchange cavity 13, through groove 14, ammonia sensitive electrode 2, touch switch 21, cooling component 3, first water wheel 31, water outlet 311, water inlet pipe 32, manual valve 33, lifting component 4, slider 41, traction line 42, gear 43, fixed pulley 44, rack 45, spring 46, second water wheel 5, alkali adding component 6, first box body 61, alkali adding pipeline 62, piston 63, cylinder 64, second box body 65. DETAILED DESCRIPTION

[0041] The following will clearly and completely describe the concept and technical effects of the present invention in combination with the embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention:

[0042] Example:

[0043] Please refer to 1- Figure 3 A device for measuring ammonia nitrogen in water quality comprises a mixing drum 1, wherein the mixing drum 1 is provided with an inner wall 11 and an outer wall 12, wherein the inner wall 11 and the outer wall 12 enclose a heat exchange cavity 13, wherein the interior of the heat exchange cavity 13 is a spiral structure, and the flow direction of the cooling medium in the heat exchange cavity 13 is as follows: Figure 1 The mixing drum 1 has through grooves 14 on the inner wall 11 and the outer wall 12 , and an ammonia gas sensitive electrode 2 is arranged in the mixing drum 1 , and the ammonia gas sensitive electrode 2 can pass through the through grooves 14 .

[0044] The cooling assembly 3 is also included. The cooling assembly 3 includes a first water wheel 31 disposed in the heat exchange cavity 13. One end of the first water wheel 31 is fixedly connected to the inner wall 11, and the other end is rotatably connected to the outer wall 12. A water outlet hole 311 is provided on the rotating shaft of the first water wheel 31. The water outlet hole 311 is connected to a water outlet pipe through a rotating joint. The first water wheel 31 rotates under the action of the flow of the cooling medium, thereby driving the inner wall 11 of the mixing drum 1 to rotate, and then stirring the water sample in the mixing drum 1.

[0045] It also includes a lifting component 4, which includes a slider 41 and a traction line 42 connected to the slider 41, and the lifting component 4 also includes a gear 43 and a fixed pulley 44. The slider 41 is fixedly connected to a rack 45, the rack 45 is meshed with the gear 43, the gear 43 is coaxially connected to a winding roller, one end of the traction line 42 passes around the fixed pulley 44 and is fixedly connected to the winding roller, the slider 41 is connected to a spring 46, the free end of the spring 46 is fixedly connected to the outer wall 12, and the free end of the traction line 42 is connected to the ammonia sensitive electrode 2. By controlling the flow rate of the cooling medium delivered by the cooling component 3, when the flow rate is large, the rack 45 is driven to move by the movement of the slider 41, and the rack 45 drives the gear 43 to rotate, so that the winding roller rotates to receive the traction line 42, and then the ammonia sensitive electrode 2 is pulled out of the water sample. When the working medium flow rate decreases, the slider 41 and the rack 45 are reset under the drive of the spring 46, thereby releasing the traction line 42 and reinserting the ammonia sensitive electrode 2 into the water sample.

[0046] Since the ammonia sensitive electrode 2 is always in a powered-on state in the water sample, when the ammonia sensitive electrode 2 is away from the water sample and exposed to the air, it is not necessary to power it on and detect it at this stage. Therefore, a touch switch 21 is provided on the outer wall 12, and the touch switch 21 is electrically connected to the ammonia sensitive electrode 2. When the slider 41 is away from the touch switch 21, the ammonia sensitive electrode 2 is powered off. When the slider 41 is away from the touch switch 21, the ammonia sensitive electrode 2 is powered off. When the slider 41 is reset and contacts the touch switch 21, the ammonia sensitive electrode 2 has been reinserted into the water sample and can be powered on.

[0047] The cooling component 3 also includes a water inlet pipe 32 and a manual valve 33 arranged on the water inlet pipe 32. The water outlet end of the water inlet pipe 32 is arranged in the heat exchange cavity 13, and the water outlet pipe is connected to the water inlet pipe 32 through a circulation pump. The water inlet pipe 32 transports cooling medium into the heat exchange cavity 13, and the medium flows along the heat exchange cavity 13 with a spiral structure, thereby covering the inner wall 11 to keep the water sample at a constant temperature and cool it down. The medium flows out through the water outlet hole, and flows to the water inlet pipe 32 through the water outlet pipe and the circulation pump, thereby realizing the recycling of the cooling medium.

[0048] During the pH adjustment stage by adding alkali solution, the water temperature rises due to the heat release of the acid-base reaction. At this time, the water sample needs to be quickly stirred to promote rapid mixing and heat dissipation. By increasing the flow rate of the cooling working fluid, the working fluid can take away heat faster, and the increase in flow rate drives the first water wheel 31 to rotate faster, so that the water sample is stirred faster, which promotes rapid mixing of the water sample and the alkali solution and heat dissipation of the water sample. In addition, after the pH is adjusted to greater than 11, constant temperature is required, and there is no need to quickly stir and dissipate heat for the water sample. At this time, the rotation speed of the first water wheel 31 is adjusted by reducing the flow rate of the working fluid to reduce the stirring intensity.

[0049] Since the salt content in the water sample is high, and the ammonia sensitive electrode 2 is immersed in the water sample, the charge on the electrode surface will attract these ions, causing them to gather on the electrode surface. Over time, these salt substances will crystallize and scale on the electrode surface, thereby affecting the potential value measured by the electrode. At the same time, due to the rotation of the mixing drum 1, bubbles will inevitably appear in the water sample and adhere to the electrode surface, which will also affect the measurement of the electrode. Therefore, this scheme also includes a second water wheel 5, which is arranged in the through groove 14, and the two ends of the second water wheel 5 are respectively connected to the inner wall 11 and the outer wall 12 for rotation. The second water wheel 5 is a hollow through-hole structure, and a brush is arranged in the through hole, and the ammonia sensitive electrode 2 can pass through so that it contacts the brush. The second water wheel 5 rotates under the action of the cooling working medium flow. When the ammonia sensitive electrode 2 is lifted to the through hole in the second water wheel 5, the second water wheel 5 drives the brush to rotate so as to clean the salt crystals and bubbles on the outer wall of the electrode.

[0050] It also includes an alkali adding component 6, which includes a pH meter arranged in the mixing drum 1 and a first box 61 arranged on the mixing drum 1, the first box 61 is connected to an alkali adding pipeline 62, the end of the alkali adding pipeline 62 is arranged in the mixing drum 1, a piston 63 is arranged in the first box 61, and a cylinder 64 is also included, the piston rod of the cylinder 64 is connected to the piston 63, the pH meter is electrically connected to a controller, and the controller is electrically connected to the cylinder 64; a limit groove 331 is provided on the handle of the manual valve 33, a bolt is provided on the piston rod of the cylinder 64, and one end of the bolt is slidably arranged in the limit groove 331. The pH value in the water sample is measured by the pH meter, and when the pH value is lower than 11, the piston rod of the cylinder 64 is controlled by the controller to extend to squeeze the alkali solution in the first box 61 into the mixing drum 1. At the same time, the extension of the piston rod will drive the bolt to move to the maximum stroke, thereby rotating the handle of the manual valve 33 to increase the flow rate of the working medium. When the pH meter detects that the pH value of the water sample is greater than 11, the controller controls the piston rod of the air cylinder 64 to retract and reversely rotate the manual valve 33 to reduce the flow rate of the working medium. Since the temperature change of the water sample is mainly due to the heat release of the acid-base reaction between the water sample and the alkali solution, the temperature will only change dramatically when the alkali solution is added. By adding alkali heat to adjust the pH value, the opening and closing degree of the manual valve 33 can be linked to the necessary operation, and the flow rate of the cooling working medium can be synchronously adjusted to achieve stirring and heat dissipation of the water sample in the mixing drum 1 and the lifting and lowering of the ammonia sensitive electrode 2.

[0051] Since there is no alkali solution in the first box 61 when the piston rod of the air cylinder 64 is retracted, the alkali adding assembly 6 further includes a second box 65, in which alkali solution is arranged, and the second box 65 is connected to the first box 61 through an alkali delivery pipeline, on which a one-way valve is arranged. The piston in the first box 61 is moved by the retraction of the piston rod of the air cylinder 64, forming a negative pressure in the first box 61, and pumping the alkali solution pre-stored in the second box 65 into the first box 61.

[0052] See also Figure 4 In order to realize the above-mentioned water quality ammonia nitrogen determination device, the present invention also provides a water quality ammonia nitrogen determination method, including the use of a water quality ammonia nitrogen determination device, including the following steps:

[0053] Step S10: preheating, placing the mixing drum 1 on a support, heating it to 38° C. in a constant temperature water bath, and keeping the temperature constant for 5 minutes;

[0054] Step S20: taking samples, respectively taking 10 mL of ammonium standard solutions with concentrations of 0.1 mg / L, 1 mg / L, 10 mg / L, and 100 mg / L into the mixing drum 1;

[0055] Step S30: electrolysis, slowly inserting the ammonia sensitive electrode 2 into the stirring drum 1, so that the semipermeable membrane of the ammonia sensitive electrode 2 is completely immersed in the water sample, and then adding 1 mL of sodium hydroxide-Na2-EDTA solution;

[0056] Step S40: measuring, during the stirring process of the mixing drum 1, observing the potential value measured by the ammonia sensitive electrode 2, and recording the reading when the potential value changes by no more than 1 mV within 1 minute;

[0057] Step S50: Determine, by recording the readings, select three or four standard points, and then draw a calibration curve of E-logc on a semi-logarithmic coordinate line.

[0058] Furthermore, in the step S30, the following steps are specifically included:

[0059] Step S31: When the pH meter detects that the pH value of the water sample is lower than 11, the controller controls the piston rod of the cylinder 64 to extend and squeeze the alkali solution in the first box 61 into the mixing drum 1 until the pH value of the water sample is not less than 11; then the controller controls the piston rod of the cylinder 64 to retract and pump the alkali solution in the second box 65 into the first box 61;

[0060] Step S32: When the piston rod of the cylinder 64 is extended, the handle of the manual valve 33 is driven to rotate, thereby increasing the flow rate of the cooling medium to make the mixing drum 1 rotate faster, and pushing the slider 41 to move to the maximum stroke to extract the ammonia sensitive electrode 2 out of the water sample; when the piston rod of the cylinder 64 is retracted, the handle of the handle valve 33 is driven to rotate in the opposite direction, thereby reducing the flow rate of the cooling medium to make the mixing drum 1 rotate slower, and the slider 41 is reset to insert the ammonia sensitive electrode 2 into the water sample;

[0061] Step S33: cleaning the ammonia sensitive electrode 2 after entering the second water wheel 5 .

[0062] The above is only an embodiment of the present invention, and the common knowledge such as the known specific structure and characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A device for measuring ammonia nitrogen in water quality, comprising a mixing drum (1) and an ammonia sensitive electrode (2) movably arranged in the mixing drum (1), wherein the mixing drum (1) is provided with a heat exchange cavity (13) formed by an inner wall (11) and an outer wall (12), wherein: Also includes: A cooling component (3), the cooling component (3) being used to transport a cooling medium into the heat exchange cavity (13); A through groove (14), wherein the through groove (14) is formed on the inner wall (11) and the outer wall (12), and the ammonia sensitive electrode (2) passes through the through groove (14); A lifting assembly (4), the lifting assembly (4) comprising a slider (41) and a traction line (42) connected to the slider (41), one end of the slider (41) being arranged in a heat exchange cavity (13), the slider (41) being connected to a reset member, and the free end of the traction line (42) being connected to an ammonia sensitive electrode (2).

2. The device for measuring ammonia nitrogen in water according to claim 1, characterized in that: The lifting assembly (4) also includes a gear (43) and a fixed pulley (44); the slider (41) is fixedly connected to a rack (45), the rack (45) is meshed with the gear (43), the gear (43) is coaxially connected to a winding roller, one end of the traction line (42) passes around the fixed pulley (44) and is fixedly connected to the winding roller; the reset member is a spring (46), one end of the spring (46) is connected to the slider (41), and the other end is connected to the outer wall (12).

3. The device for measuring ammonia nitrogen in water according to claim 1, characterized in that: A touch switch (21) is provided on the outer wall (12), and the touch switch (21) is electrically connected to the ammonia sensitive electrode (2). When the slider (41) moves away from the touch switch (21), the ammonia sensitive electrode (2) is powered off.

4. The device for measuring ammonia nitrogen in water according to claim 1, characterized in that: The cooling component (3) comprises a first water wheel (31) arranged in the heat exchange cavity (13); one end of the first water wheel (31) is fixedly connected to the inner wall (11), and the other end is rotatably connected to the outer wall (12).

5. A water quality ammonia nitrogen measuring device according to claim 4, characterized in that: The heat exchange cavity (13) is a heat exchange cavity (13) with a spiral structure, and a water outlet hole (311) is provided on the rotating shaft of the first water wheel (31); the cooling component (3) also includes a water inlet pipe (32) and a manual valve (33) arranged on the water inlet pipe (32), and the water outlet end of the water inlet pipe (32) is arranged in the heat exchange cavity (13); the water outlet hole (311) is connected to the water outlet pipe through a rotating joint, and the water outlet pipe and the water inlet pipe (32) are connected through a circulating pump.

6. The device for measuring ammonia nitrogen in water according to claim 1, characterized in that: It also includes a second water wheel (5), which is arranged in the through groove (14), and the two ends of the second water wheel (5) are rotatably connected to the inner wall (11) and the outer wall (12) respectively, and the second water wheel (5) is a through hole structure, and a brush is arranged inside the through hole.

7. The device for measuring ammonia nitrogen in water according to claim 5, characterized in that: The invention also comprises an alkali adding component (6), the alkali adding component (6) comprising a pH meter arranged in the mixing drum (1) and a first box body (61) arranged on the mixing drum (1), the first box body (61) being connected to an alkali adding pipeline (62), the end of the alkali adding pipeline (62) being arranged in the mixing drum (1), a piston (63) being arranged in the first box body (61), and a cylinder (64), the piston rod of the cylinder (64) being connected to the piston (63), the pH meter being electrically connected to a controller, and the controller being electrically connected to the cylinder (64); a limit groove (331) being provided on the handle of the manual valve (33), a bolt being provided on the piston rod of the cylinder (64), one end of the bolt being slidably arranged in the limit groove (331).

8. The device for measuring ammonia nitrogen in water according to claim 7, characterized in that: The alkali adding assembly (6) further comprises a second box (65), wherein the second box (54) is provided with alkali solution, and the second box (65) is connected to the first box (61) via an alkali delivery pipeline; a one-way valve is provided on the alkali delivery pipeline.

9. A method for determining ammonia nitrogen in water quality, comprising using a device for determining ammonia nitrogen in water quality as claimed in any one of claims 1 to 8, characterized in that: The steps include: Step S10: preheating, placing the mixing drum (1) on a support, heating it to 38° C. in a constant temperature water bath, and maintaining the temperature for 5 minutes; Step S20: taking samples, respectively taking 10 mL of ammonium standard solutions with concentrations of 0.1 mg / L, 1 mg / L, 10 mg / L, and 100 mg / L into the mixing drum (1); Step S30: electrolysis, slowly inserting the ammonia sensitive electrode (2) into the stirring drum (1) so that the semipermeable membrane of the ammonia sensitive electrode (2) is completely immersed in the water sample, and then adding 1 mL of sodium hydroxide-Na2-EDTA solution; Step S40: measuring, during the stirring process of the stirring drum (1), observing the potential value measured by the ammonia sensitive electrode (2), and recording the reading when the potential value changes by no more than 1 mV within 1 minute; Step S50: Determine, by recording the readings, select three or four standard points, and then draw a calibration curve of E-logc on a semi-logarithmic coordinate line.

10. A method for determining ammonia nitrogen in water according to claim 9, characterized in that: In the step S30, the following steps are specifically included: Step S31: When the pH meter detects that the pH value of the water sample is lower than 11, the controller controls the piston rod of the air cylinder (64) to extend and squeeze the alkali solution in the first box (61) into the mixing drum (1) until the pH value of the water sample is not less than 11; then the controller controls the piston rod of the air cylinder (64) to retract and pump the alkali solution in the second box (65) into the first box (61); Step S32: When the piston rod of the air cylinder (64) is extended, the handle of the manual valve (33) is driven to rotate, thereby increasing the flow rate of the cooling medium so that the mixing drum (1) rotates faster, and the slider (41) is pushed to move to the maximum stroke so that the ammonia sensitive electrode (2) is pulled out of the water sample; when the piston rod of the air cylinder (64) is retracted, the handle of the handle valve (33) is driven to rotate in the opposite direction, thereby reducing the flow rate of the cooling medium so that the mixing drum (1) rotates slower, and the slider (41) is reset so that the ammonia sensitive electrode (2) is inserted into the water sample; Step S33: cleaning the ammonia sensitive electrode (2) after entering the second water wheel (5).

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