Sampling detection self-circulation system in hot-dip galvanizing

Abstract

The invention belongs to the field of hot-dip galvanizing, and particularly relates to a sampling detection self-circulation system in hot-dip galvanizing. Comprising a plating pipe pretreatment tank, a circulating pump, a first electromagnetic three-way valve, a sampling pump, a second electromagnetic three-way valve, a detection device and a cleaning liquid storage tank, a liquid inlet and a liquid outlet of the circulating pump are communicated with the plating pipe pretreatment tank through circulating pipes, and the circulating pipe between the liquid outlet of the circulating pump and the plating pipe pretreatment tank is communicated with a sampling pipe; the sampling pipe conveys a sample solution into the detection device through a first electromagnetic three-way valve, a sampling pump and a second electromagnetic three-way valve in sequence, the other port of the first electromagnetic three-way valve is communicated with a waste liquid discharge pipe, the other port of the second electromagnetic three-way valve is communicated with a cleaning liquid storage tank through a flushing pipe, and the sampling pump is a two-way pump. According to the invention, samples can be directly sampled from the circulating pipe and conveyed to the detection device for detection, so that automatic sampling and on-line detection work can be realized, and the detection efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the field of hot dip galvanizing, and particularly relates to a sampling and detection self-circulation system in hot dip galvanizing. Background Art

[0002] Hot dip galvanizing is one of the most effective means to delay the environmental corrosion of steel materials. It immerses the steel products with their surfaces cleaned and activated in molten zinc liquid, and through the reaction and diffusion between iron and zinc, a zinc alloy coating with good adhesion is plated on the surface of the steel products. Compared with other metal protection methods, the hot dip galvanizing process has unparalleled advantages in terms of the combined protection characteristics of the physical barrier and electrochemical protection of the coating, the bonding strength between the coating and the substrate, the density, durability, maintenance-free property and economy of the coating, and its adaptability to the shape and size of the products. For a long time, the hot dip galvanizing process has been favored by people because of its low plating cost, excellent protection characteristics and beautiful appearance, and is widely used in fields such as automobiles, construction, household appliances, chemical engineering, machinery, petroleum, metallurgy, light industry, transportation, electric power, aviation and marine engineering.

[0003] The application of flux in the production process of hot dip galvanized steel pipes is a very important process in the pre-treatment process before zinc dipping. At present, the solvent fluxing method, hydrochloric acid fluxing, redox method and hot dip aluminizing method are studied and applied at home and abroad. Among them, the solvent fluxing method has the simplest and most feasible features. The solvent is an aqueous solution of ammonium chloride and zinc chloride, which covers some advantages generated when hydrochloric acid, zinc chloride and ammonium chloride are used as fluxes, and at the same time overcomes the disadvantages of these single fluxes. Therefore, the zinc layer plated after immersion in this mixed aqueous solution has the characteristics of excellent quality, few defective products, little zinc slag, and not easy to get damp after drying, so it has been widely adopted by the hot dip galvanizing industry at present. The factors affecting the fluxing effect mainly include 4: total flux concentration, fluxing temperature, fluxing pH value and Fe 2+ concentration. Among them, the total flux concentration and the ammonium-zinc ratio therein are the factors that have the greatest influence on the fluxing effect. If the total flux concentration is low or the ammonium-zinc ratio is not within the normal range, the fluxing effect will be reduced, which will in turn affect the subsequent galvanizing of the steel surface and produce defective products. Therefore, during the hot dip galvanizing process, it is necessary to frequently sample and measure the solution to monitor the flux concentration and the concentration ratio of ammonium ions and zinc ions in the solution in real time, so as to ensure the fluxing quality. The existing detection methods mainly rely on manual sampling and off-line detection, which are not only inefficient but also require a waste of a large amount of manpower. Therefore, there is an urgent need to design a sampling and detection self-circulation system in hot dip galvanizing that can automatically sample and quickly detect the relevant parameters of the flux online. Summary of the Invention

[0004] In view of the problems existing in the above-mentioned prior art, the present invention provides a sampling and detection self-circulation system in hot dip galvanizing, and specifically discloses the following technical solutions:

[0005] A self - circulating system for sampling and detection in hot - dip galvanizing, comprising a pre - treatment tank for galvanized pipes, a circulation pump, a first electromagnetic three - way valve, a sampling pump, a second electromagnetic three - way valve, a detection device and a cleaning liquid storage tank. The liquid inlet and outlet of the circulation pump are respectively connected to the pre - treatment tank for galvanized pipes through a circulation pipe. A sampling pipe is connected to the circulation pipe between the outlet of the circulation pump and the pre - treatment tank for galvanized pipes. The sampling pipe sequentially transports the sample solution to the detection device through the first electromagnetic three - way valve, the sampling pump and the second electromagnetic three - way valve. One port of the first electromagnetic three - way valve that is not connected to the sampling pipe is connected to a waste liquid discharge pipe. One port of the second electromagnetic three - way valve that is not connected to the sampling pipe is connected to the cleaning liquid storage tank through a flushing pipe. The sampling pump is a two - way pump.

[0006] Further, the liquid inlet of the circulation pump is connected to the bottom of the pre - treatment tank for galvanized pipes through a circulation pipe, and the liquid outlet of the circulation pump is connected to the top of the pre - treatment tank for galvanized pipes through a circulation pipe.

[0007] Further, a filter screen is installed at the liquid inlet end of the circulation pipe connected to the liquid inlet of the circulation pump.

[0008] Further, the detection device includes a base. A first driving motor is fixedly installed at the center of the base. The output shaft of the first driving motor is vertically upward and fixedly connected to a rotating shaft. The top of the rotating shaft is fixedly connected to a turntable. Three groups of sampling containers are evenly arranged around the upper surface of the turntable. Each group of sampling containers includes two sampling containers. A liquid discharge port is arranged at the bottom end of each sampling container, and a first electromagnetic switch valve is installed at each liquid discharge port. The liquid outlet end of the sampling pipe is fixed above one group of sampling containers through a horizontal driving mechanism. A potentiometric titration mechanism and a cleaning mechanism are respectively arranged above the other two groups of sampling containers. The potentiometric titration mechanism is used to detect the concentrations of ammonium ions and zinc ions in the sample solution, and the cleaning mechanism is used to clean the used sampling containers.

[0009] Further, the horizontal driving mechanism includes a support rod. The lower part of the support rod is fixedly connected to the side surface of the base. The top of the support rod is fixedly connected to a mounting seat. A chute is opened on the upper surface of the mounting seat. A lead screw is rotatably connected in the chute. One end of the lead screw penetrates through the side wall of the chute and is fixedly connected to the output shaft of a second driving motor. A slider is slidably installed in the chute. The slider is sleeved on the lead screw and is threadedly connected to the lead screw. The top of the slider is fixedly connected to a connecting plate. One end of the connecting plate away from the slider is fixedly connected to a fixing seat. The liquid outlet end of the sampling pipe is fixed on the fixing seat, and the liquid outlet end of the sampling pipe is connected to a first electromagnetic flow valve.

[0010] Further, the potentiometric titration mechanism includes a first fixing plate. On both sides of the bottom end of the first fixing plate, a first lifting plate and a second lifting plate are respectively connected through two groups of first hydraulic telescopic rods. A first stirring motor is installed on the upper surface of the first lifting plate. The output shaft of the first stirring motor vertically penetrates the first lifting plate downward and is fixedly connected with a first stirring shaft. Stirring blades are installed on the side wall of the first stirring shaft. A first liquid adding pipe, a first titration pipe, a first indicating electrode and a first reference electrode are installed at the bottom of the first lifting plate. The tops of the first liquid adding pipe and the first titration pipe are respectively communicated with corresponding infusion hoses through second electromagnetic flow valves. Both the first reference electrode and the first indicating electrode are electrically connected to the first potentiometric titration instrument host. A second stirring motor is installed on the upper surface of the second lifting plate. The output shaft of the second stirring motor vertically penetrates the second lifting plate downward and is fixedly connected with a second stirring shaft. Stirring blades are installed on the side wall of the second stirring shaft. A second liquid adding pipe, a third liquid adding pipe, a fourth liquid adding pipe, a second titration pipe, a second indicating electrode and a second reference electrode are installed at the bottom of the second lifting plate. The second liquid adding pipe, the third liquid adding pipe, the fourth liquid adding pipe and the second titration pipe are respectively communicated with corresponding infusion hoses through third electromagnetic flow valves. Both the second reference electrode and the second indicating electrode are electrically connected to the second potentiometric titration instrument host.

[0011] Further, the cleaning mechanism includes a second fixing plate. On both sides of the bottom end of the second fixing plate, a third lifting plate and a fourth lifting plate are respectively connected through two groups of second hydraulic telescopic rods. Cleaning pipes are fixedly installed at the bottoms of the third lifting plate and the fourth lifting plate respectively. Disc nozzles are respectively communicated with the bottoms of the two cleaning pipes. The tops of the two cleaning pipes are respectively communicated with corresponding infusion hoses through second electromagnetic switching valves.

[0012] Further, a waste liquid collection tank is arranged on the base at a position directly below the cleaning mechanism.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0014] In the present invention, the sampling pipe is communicated with the circulation pipe through a second electromagnetic three-way valve, a sampling pump and a first electromagnetic three-way valve, and can directly sample from the circulation pipe and transport it to the detection device for detection, so as to realize automatic sampling and on-line detection work. Moreover, the sampling pump is a two-way pump. One port of the first electromagnetic three-way valve that is not communicated with the sampling pipe is communicated with a waste liquid discharge pipe. One port of the second electromagnetic three-way valve that is not communicated with the sampling pipe is communicated with a cleaning liquid storage tank through a flushing pipe. By changing the running direction of the sampling pump, the cleaning liquid in the cleaning liquid storage tank can be pumped into the sampling pipe to clean the sampling pipe, so as to avoid affecting the next sampling. Description of the Drawings

[0015] Figure 1Schematic diagram of the overall structure of the present invention.

[0016] Figure 2 Top view of the detection device in the present invention.

[0017] Figure 3 Front view of a partial structure of the detection device in the present invention.

[0018] Figure 4 Front view of the potentiometric titration mechanism in the present invention.

[0019] Figure 5 Front view of the cleaning mechanism in the present invention.

[0020] 1 - Pretreatment tank for plating pipes, 2 - Circulation pump, 3 - First electromagnetic three - way valve, 4 - Sampling pump, 5 - Second electromagnetic three - way valve, 6 - Detection device, 61 - Base, 62 - Rotating shaft, 63 - Turntable, 64 - Sampling container, 641 - First electromagnetic switch valve, 65 - Horizontal driving mechanism, 651 - Support rod, 652 - Mounting seat, 653 - Lead screw, 654 - Second driving motor, 655 - Slide block, 656 - Fixed seat, 657 - First electromagnetic flow valve, 66 - Potentiometric titration mechanism, 6601 - First fixing plate, 6602 - First hydraulic telescopic rod, 6603 - First lifting plate, 6604 - Second lifting plate, 6605 - First stirring motor, 6606 - First stirring shaft, 6607 - First liquid adding pipe, 6608 - First burette, 6609 - First indicating electrode, 6610 - First reference electrode, 6611 - Second stirring motor, 6612 - Second stirring shaft, 6613 - Second liquid adding pipe, 6614 - Third liquid adding pipe, 6615 - Fourth liquid adding pipe, 6616 - Second burette, 6617 - Second indicating electrode, 6618 - Second reference electrode, 67 - Cleaning mechanism, 671 - Second fixing plate, 672 - Second hydraulic telescopic rod, 673 - Third lifting plate, 674 - Fourth lifting plate, 675 - Cleaning pipe, 676 - Disk nozzle, 677 - Second electromagnetic switch valve, 68 - Waste liquid collection tank, 7 - Cleaning liquid storage tank, 8 - Sampling pipe, 9 - Waste liquid discharge pipe, 10 - Flushing pipe. Detailed implementation manners

[0021] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0022] Refer to Figures 1-5, A self - circulating sampling and detection system in hot - dip galvanizing, comprising a pre - treatment tank 1 for galvanized pipes, a circulation pump 2, a first electromagnetic three - way valve 3, a sampling pump 4, a second electromagnetic three - way valve 5, a detection device 6 and a cleaning liquid storage tank 7. The inlet and outlet of the circulation pump 2 are respectively connected to the pre - treatment tank 1 for galvanized pipes through a circulation pipe. The circulation pump 2 and the circulation pipe are arranged such that the solution in the pre - treatment tank 1 for galvanized pipes can be circulated, thereby ensuring uniform dissolution of its solutes. A sampling pipe 8 is connected to the circulation pipe between the outlet of the circulation pump 2 and the pre - treatment tank 1 for galvanized pipes. The sampling pipe 8 transports sample solution to the detection device 6 through the first electromagnetic three - way valve 3, the sampling pump 4 and the second electromagnetic three - way valve 5 in sequence. One port of the first electromagnetic three - way valve 3 that is not connected to the sampling pipe 8 is connected to a waste liquid discharge pipe 9. One port of the second electromagnetic three - way valve 5 that is not connected to the sampling pipe 8 is connected to the cleaning liquid storage tank 7 through a flushing pipe 10. The sampling pump 4 is a two - way pump. When sampling is required, the first electromagnetic three - way valve and the second electromagnetic three - way valve 5 can be adjusted so that the entire sampling pipe 8 is connected to the circulation pipe, thereby transporting sample solution to the detection device 6 through the sampling pump 4. After sampling is completed, the working direction of the sampling pump 4 can be changed to make the solution in the sampling pipe 8 return to the circulation pipe again, and then the first electromagnetic three - way valve 3 and the second electromagnetic three - way valve 5 are adjusted so that the cleaning liquid storage tank 7, the flushing pipe 10, the sampling pipe 8 and the waste liquid discharge pipe 9 are connected in sequence, thereby using the cleaning liquid in the cleaning liquid storage tank 7 to clean the above - mentioned pipelines to avoid the influence of the residual solution therein on the next sampling and measurement results.

[0023] In this embodiment, the inlet of the circulation pump 2 is connected to the bottom of the pre - treatment tank 1 for galvanized pipes through a circulation pipe, and the outlet of the circulation pump 2 is connected to the top of the pre - treatment tank 1 for galvanized pipes through a circulation pipe.

[0024] In this embodiment, a filter screen is installed at the inlet end of the circulation pipe connected to the inlet of the circulation pump 2, which can not only prevent the iron sludge in the pre - treatment tank 1 for galvanized pipes from entering the circulation pipe and the sampling pipe 8 and causing blockage of the relevant pipelines, but also ensure that the sampling solution is a clear liquid, thereby avoiding the influence of iron sludge on the detection of relevant ion concentrations.

[0025] In this embodiment, the detection device 6 includes a base 61. A first drive motor is fixedly installed at the center of the base 61. The output shaft of the first drive motor is arranged vertically upward and fixedly connected to a rotating shaft 62. The top end of the rotating shaft 62 is fixedly connected to a turntable 63. Three groups of sampling containers are evenly arranged around the upper surface of the turntable 63. Each group of sampling containers includes two sampling containers 64. A liquid discharge port is arranged at the bottom end of each sampling container 64. A first electromagnetic solenoid valve 641 is installed at each liquid discharge port. The liquid outlet end of the sampling tube 8 is fixed above one group of sampling containers through a horizontal drive mechanism 65. A potentiometric titration mechanism 66 and a cleaning mechanism 67 are respectively arranged above the other two groups of sampling containers. The potentiometric titration mechanism 66 is used to detect the ammonium ion and zinc ion concentrations in the sample solution. The cleaning mechanism 67 is used to clean the used sampling containers 64. The first drive motor can drive the rotation of the rotating shaft 62 and the turntable 63, so that the three groups of sampling containers on the turntable 63 can alternately move below the liquid outlet end of the sampling tube 8, so that the three groups of containers can alternately receive the sample solution. The group of sampling containers that has received the sample solution rotates below the potentiometric titration mechanism 66, and the two sampling containers 64 respectively detect the ammonium ion and zinc ion concentrations to avoid mutual influence during the detection process. After the detection is completed, this group of sampling containers continues to rotate below the cleaning mechanism 67 for cleaning. After the cleaning is completed, the next round of work of receiving the sample solution starts.

[0026] In this embodiment, the horizontal drive mechanism 65 includes a support rod 651. The lower part of the support rod 651 is fixedly connected to the side surface of the base 61. The top end of the support rod 651 is fixedly connected to a mounting seat 652. A chute is opened on the upper surface of the mounting seat 652. A lead screw 653 is rotatably connected in the chute. One end of the lead screw 653 penetrates through the side wall of the chute and is fixedly connected to the output shaft of a second drive motor 654. A slider 655 is slidably installed in the chute. The slider 655 is sleeved on the lead screw 653 and is threadedly connected to the lead screw 653. The top end of the slider 655 is fixedly connected to a connecting plate. One end of the connecting plate away from the slider 655 is fixedly connected to a fixed seat 656. The liquid outlet end of the sampling tube 8 is fixed on the fixed seat 656. The liquid outlet end of the sampling tube 8 is communicated with a first electromagnetic flow valve 657. By driving the rotation of the lead screw 653 by the second drive motor 654, the slider 655 can be moved in the chute, so as to drive the fixed seat 656 and the liquid outlet end of the sampling tube 8 to move through the connecting plate. That is, when one of the sampling containers 64 in a group of sampling containers receives a predetermined amount of sample solution, the liquid outlet end of the sampling tube 8 can move above another sampling container 64 along with the fixed seat 656, so that both sampling containers 64 can receive a predetermined amount of sample solution successively.

[0027] In this embodiment, the potentiometric titration mechanism 66 includes a first fixing plate 6601, which is fixed on the support frame above it. On both sides of the bottom end of the first fixing plate 6601, a first lifting plate 6603 and a second lifting plate 6604 are respectively connected through two groups of first hydraulic telescopic rods 6602. A first stirring motor 6605 is installed on the upper surface of the first lifting plate 6603. The output shaft of the first stirring motor 6605 vertically penetrates the first lifting plate 6603 and is fixedly connected with a first stirring shaft 6606. Stirring blades are installed on the side wall of the first stirring shaft 6606. A first liquid adding pipe 6607, a first titration pipe 6608, a first indicating electrode 6609 and a first reference electrode 6610 are installed at the bottom of the first lifting plate 6603. The tops of the first liquid adding pipe 6607 and the first titration pipe 6608 are respectively communicated with the corresponding infusion hoses through second electromagnetic flow valves. Both the first reference electrode 6610 and the first indicating electrode 6609 are electrically connected to a first potentiometric titrator main unit (not shown in the figure). A second stirring motor 6611 is installed on the upper surface of the second lifting plate 6604. The output shaft of the second stirring motor 6611 vertically penetrates the second lifting plate 6604 and is fixedly connected with a second stirring shaft 6612. Stirring blades are installed on the side wall of the second stirring shaft 6612. A second liquid adding pipe 6613, a third liquid adding pipe 6614, a fourth liquid adding pipe 6615, a second titration pipe 6616, a second indicating electrode 6617 and a second reference electrode 6618 are installed at the bottom of the second lifting plate 6604. The second liquid adding pipe 6613, the third liquid adding pipe 6614, the fourth liquid adding pipe 6615 and the second titration pipe 6616 are respectively communicated with the corresponding infusion hoses through third electromagnetic flow valves. Both the second reference electrode 6618 and the second indicating electrode 6617 are electrically connected to a second potentiometric titrator main unit (not shown in the figure). The first lifting plate 6603 and the second lifting plate 6604 respectively align with two of the sampling containers in a group of sampling containers 64. The sampling container 64 below the first lifting plate 6603 is used for detecting the ammonium ion concentration, and the sampling container 64 below the second lifting plate 6604 is used for detecting the zinc ion concentration.When detecting the ammonium ion concentration, the first hydraulic telescopic rod 6602 drives the first lifting plate 6603 to descend. The first stirring shaft 6606, the first liquid adding pipe 6607, the first burette 6608, the first indicating electrode 6609 and the first reference electrode 6610 are all inserted into the sampling container 64 below. A certain amount of formaldehyde is added to the sampling container 64 through the first liquid adding pipe 6607. The sample solution is fully stirred by the first stirring shaft 6606 and the stirring blades thereon. Then, sodium hydroxide solution is dropped into the sampling container 64 through the first burette 6608, and the titration end point is determined according to the potentiometric titration curve displayed by the first potentiometric titrator main unit. Finally, the ammonium ion concentration in the pre-treatment tank 1 of the plating pipe is calculated by a computer based on the concentration and volume of the dropped sodium hydroxide solution, so as to facilitate judging whether ammonium ions need to be added to the pre-treatment tank 1 of the plating pipe. When detecting the zinc ion concentration, the first hydraulic telescopic rod 6602 drives the second lifting plate 6604 to descend. The second stirring shaft 6612, the second liquid adding pipe 6613, the third liquid adding pipe 6614, the fourth liquid adding pipe 6615, the second burette 6616, the second indicating electrode 6617 and the second reference electrode 6618 are all inserted into the sampling container 64 below. An appropriate amount of ammonia water is added to the sampling container 64 through the second liquid adding pipe 6613 to neutralize the sample solution to neutral. Then, an appropriate amount of ammonia-ammonium chloride buffer solution is added to the sampling container 64 through the third liquid adding pipe 6614. EDTA is dropped into the sampling container 64 through the second burette 6616, and the replacement agent Cu-EDTA is added to the sampling container 64 through the fourth liquid adding pipe 6615. Finally, the titration end point is determined according to the potentiometric titration curve displayed by the second potentiometric titrator main unit, so as to calculate the zinc ion concentration in the pre-treatment tank 1 of the plating pipe according to the concentration and volume of the dropped EDTA, so as to facilitate judging whether zinc ions need to be added to the pre-treatment tank 1 of the plating pipe.

[0028] In this embodiment, the cleaning mechanism 67 includes a second fixing plate 671. The second fixing plate 671 is fixed on the corresponding support frame. The two sides of the bottom end of the second fixing plate 671 are respectively connected with a third lifting plate 673 and a fourth lifting plate 674 through two groups of second hydraulic telescopic rods 672. Cleaning pipes 675 are fixedly installed at the bottom ends of the third lifting plate 673 and the fourth lifting plate 674 respectively. The bottom ends of the two cleaning pipes 675 are respectively communicated with disc nozzles 676. The top ends of the two cleaning pipes 675 are respectively communicated with the corresponding infusion hoses through second electromagnetic solenoid valves 677. The third lifting plate 673 and the fourth lifting plate 674 are respectively driven by the two groups of second hydraulic telescopic rods 672 to descend and respectively extend into the two sampling containers 64 below. Cleaning liquid is sprayed into the two sampling containers 64 through the two disc nozzles 676 respectively to clean the sampling containers 64. When cleaning, the drain ports at the bottoms of the two sampling containers 64 are opened, so that the cleaning waste liquid can be discharged.

[0029] In this embodiment, a waste liquid collection tank 68 is provided at a position directly below the cleaning mechanism 67 on the base 61, which can collect the cleaning waste liquid.

[0030] In the present invention, the sampling tube is connected to the circulation tube through a second electromagnetic three-way valve, a sampling pump, and a first electromagnetic three-way valve, and can directly sample from the circulation tube and transport it to the detection device for detection, so that automatic sampling and on-line detection can be realized. The sampling pump is a two-way pump, and a waste liquid discharge tube is connected to a port of the first electromagnetic three-way valve that is not connected to the sampling tube. A port of the second electromagnetic three-way valve that is not connected to the sampling tube is connected to the cleaning liquid storage tank through a flushing tube. By changing the running direction of the sampling pump, the cleaning liquid in the cleaning liquid storage tank can be pumped into the sampling tube to clean the sampling tube, so as to avoid affecting the next sampling, and thus the accuracy of the detection result can be ensured.

[0031] The above is only a preferred embodiment of the present invention, and does not impose any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A self-circulating system for sampling and testing in hot-dip galvanizing, characterized in that: It includes a plating tube pretreatment tank, a circulation pump, a first electromagnetic three-way valve, a sampling pump, a second electromagnetic three-way valve, a detection device and a cleaning liquid storage tank. The liquid inlet and the liquid outlet of the circulation pump are respectively connected to the plating tube pretreatment tank through a circulation pipe, and a sampling pipe is connected to the circulation pipe between the liquid outlet of the circulation pump and the plating tube pretreatment tank. The sampling pipe transports the sample solution to the detection device through the first electromagnetic three-way valve, the sampling pump and the second electromagnetic three-way valve in sequence. One opening of the first electromagnetic three-way valve that is not connected to the sampling tube is connected to a waste liquid discharge pipe, and one opening of the second electromagnetic three-way valve that is not connected to the sampling tube is connected to the cleaning liquid storage tank through a flushing pipe. The sampling pump is a bidirectional pump.

2. A hot dip galvanizing sampling and detection self-circulation system according to claim 1, characterized in that: The liquid inlet of the circulation pump is connected to the bottom of the plating tube pretreatment tank through a circulation pipe, and the liquid outlet of the circulation pump is connected to the top of the plating tube pretreatment tank through a circulation pipe.

3. A hot dip galvanizing sampling and detection self-circulation system according to claim 2, characterized in that: A filter screen is installed at the liquid inlet end of the circulation pipe connected to the liquid inlet of the circulation pump.

4. The hot-dip galvanizing sampling and detection self-circulation system according to claim 1, characterized in that: The detection device includes a base, a first drive motor is fixedly installed at the center of the base, the output shaft of the first drive motor is vertically arranged upward and fixedly connected to a rotating shaft, the top of the rotating shaft is fixedly connected to a turntable, three groups of sampling containers are evenly arranged on the outer periphery of the upper surface of the turntable, each group of sampling containers includes two sampling containers, the bottom end of each sampling container is provided with a drain port, each drain port is installed with a first electromagnetic switch valve, the liquid outlet end of the sampling tube is fixed to the top of one group of sampling containers through a horizontal driving mechanism, and a potentiometric titration mechanism and a cleaning mechanism are respectively arranged above the other two groups of sampling containers, the potentiometric titration mechanism is used to detect the concentrations of ammonium ions and zinc ions in the sample solution, and the cleaning mechanism is used to clean the used sampling containers.

5. A hot dip galvanizing sampling and detection self-circulation system according to claim 4, characterized in that: The horizontal driving mechanism includes a support rod, the lower part of the support rod is fixedly connected to the side of the base, the top of the support rod is fixedly connected to a mounting seat, the upper surface of the mounting seat is provided with a slide groove, a lead screw is rotatably connected in the slide groove, one end of the lead screw passes through the side wall of the slide groove and is fixedly connected to the output shaft of the second driving motor, a slider is slidably installed in the slide groove, the slider is sleeved on the lead screw and threadedly connected to the lead screw, the top of the slider is fixedly connected to a connecting plate, the end of the connecting plate away from the slider is fixedly connected to a fixing seat, the liquid outlet end of the sampling tube is fixed on the fixing seat, and the liquid outlet end of the sampling tube is connected to a first electromagnetic flow valve.

6. A hot dip galvanizing sampling and detection self-circulation system according to claim 4, characterized in that: The potentiometric titration mechanism comprises a first fixed plate, the bottom end of the first fixed plate is connected to a first lifting plate and a second lifting plate on both sides through two groups of first hydraulic telescopic rods, a first stirring motor is installed on the upper surface of the first lifting plate, the output shaft of the first stirring motor vertically passes through the first lifting plate downward and is fixedly connected to a first stirring shaft, a stirring blade is installed on the side wall of the first stirring shaft, a first liquid adding tube, a first burette, a first indicator electrode and a first reference electrode are installed at the bottom of the first lifting plate, the top ends of the first liquid adding tube and the first burette are respectively connected to corresponding infusion hoses through second electromagnetic flow valves, the first reference electrode and the first indicator electrode are connected to the first reference electrode and the first indicator electrode. The second electrodes are electrically connected to the first potentiometric titrator host, a second stirring motor is installed on the upper surface of the second lifting plate, an output shaft of the second stirring motor vertically passes through the second lifting plate downward and is fixedly connected to the second stirring shaft, a stirring blade is installed on the side wall of the second stirring shaft, a second liquid adding tube, a third liquid adding tube, a fourth liquid adding tube, a second burette, a second indicator electrode and a second reference electrode are installed at the bottom of the second lifting plate, the second liquid adding tube, the third liquid adding tube, the fourth liquid adding tube and the second burette are respectively connected to the corresponding infusion hose through the third electromagnetic flow valve, and the second reference electrode and the second indicator electrode are electrically connected to the second potentiometric titrator host.

7. A hot dip galvanizing sampling and detection self-circulation system according to claim 4, characterized in that: The cleaning mechanism includes a second fixed plate, and the third lifting plate and the fourth lifting plate are connected to the two sides of the bottom end of the second fixed plate through two groups of second hydraulic telescopic rods respectively, and the bottoms of the third lifting plate and the fourth lifting plate are respectively fixedly installed with cleaning pipes, and the bottom ends of the two cleaning pipes are respectively connected to disc nozzles, and the top ends of the two cleaning pipes are respectively connected to the corresponding infusion hoses through second electromagnetic switch valves.

8. The hot-dip galvanizing sampling and detection self-circulation system according to claim 4, characterized in that: A waste liquid collecting tank is arranged on the base directly below the cleaning mechanism.

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