Coating liquid circulating system of continuous annealing unit

Abstract

The invention relates to the technical field of coating liquid systems of continuous annealing units, in particular to a coating liquid circulating system of a continuous annealing unit. The invention provides a coating liquid circulating system of a continuous annealing unit, which comprises a coating machine, a circulating tank and a pipeline assembly, a first delivery pump is arranged on a first liquid inlet pipe, and a second delivery pump is arranged on a second liquid inlet pipe; the two ends of the liquid return bypass are communicated with the liquid return pipeline respectively, a liquid return pump is arranged on the liquid return bypass, the cleaning ball and the stirrer of the circulating tank are arranged in the circulating tank, the cleaning ball is arranged on the side, close to the top, of the circulating tank, and the cooling device is used for cooling the coating liquid in the circulating tank. The high-viscosity, high-solid-content and high-density coating liquid can be stably supplied and returned, the conveying amount of the coating liquid can be automatically adjusted, the stability and uniformity of roller coating are improved, and the high-viscosity, high-solid-content and high-density coating liquid can be stably conveyed; a liquid return pump is arranged on a liquid return pipeline of the coating machine, so that the coating liquid can be assisted to return to the circulating tank.

Description

Technical Field

[0001] The present disclosure relates to the technical field of coating liquid systems for continuous annealing units, and in particular to a coating liquid circulation system for a continuous annealing unit. Background Art

[0002] The coating process in the continuous annealing unit involves first applying a coating liquid to the strip surface via a coating machine, then drying and curing it in a drying furnace, thereby forming an insulating coating on the strip surface. With technological advancements and increasing environmental awareness, the requirements for the insulation performance and environmental protection of steel strip are becoming increasingly stringent. Consequently, the application of environmentally friendly coatings in continuous annealing units is becoming increasingly widespread. However, environmentally friendly coatings are high-viscosity, high-solids, high-density, and somewhat corrosive fluids with poor fluidity. The C6 environmentally friendly coating has the worst fluidity, with a maximum viscosity of approximately 5000 cP, a maximum solids content of approximately 78%, and a maximum density of approximately 1.9 g / ml. Existing coating circulation systems using diaphragm pumps are no longer able to continuously and stably deliver the C6 environmentally friendly coating to the coating machine. Furthermore, relying solely on gravity return is also extremely difficult, resulting in the coating machine being unable to properly roll coat. In addition, different strip steel products require different types of coating liquids, and the physical properties of various coating liquids vary greatly, which also have different impacts on the delivery capacity of the delivery pump. Therefore, each time the coating liquid type is switched, the coating liquid flow rate needs to be manually adjusted. However, the manually adjusted flow rate error is large, resulting in poor stability and uniformity of roller coating. Summary of the Invention

[0003] The present disclosure aims to solve at least one of the technical problems existing in the prior art or related art.

[0004] To this end, the present disclosure provides a coating liquid circulation system of a continuous annealing unit, including a coating machine, a circulation tank and a pipeline assembly, the pipeline assembly including a first liquid inlet pipe, a second liquid inlet pipe, a third liquid inlet pipe, a liquid return pipe and a liquid return bypass passage, one end of the liquid return pipe is connected to the liquid discharge port of the coating machine, and the other end thereof is connected to the liquid inlet of the circulation tank, and a liquid return valve is provided on the side of the liquid return pipe close to the circulation tank, one end of the first liquid inlet pipe and the second liquid inlet pipe are connected in parallel to the liquid discharge port of the circulation tank, and the other end thereof is connected in parallel to the liquid discharge port of the third liquid inlet pipe. The outlet of the third liquid inlet pipe is connected to the liquid replenishing port of the coating machine, the first liquid inlet pipe is provided with a first delivery pump, and the second liquid inlet pipe is provided with a second delivery pump; the two ends of the return liquid bypass passage are respectively connected to the return liquid pipeline, and the return liquid bypass passage is provided with a return liquid pump, the circulation tank includes a tank body, a cleaning ball, an agitator and a cooling device, the cleaning ball and the agitator are arranged inside the circulation tank, and the cleaning ball is arranged on the side of the circulation tank near the top, and the cooling device is used to cool the coating liquid in the circulation tank.

[0005] In a feasible embodiment, it also includes a first liquid inlet bypass and a second liquid inlet bypass, the first liquid inlet bypass and the second liquid inlet bypass are arranged opposite to each other, the two ends of the first liquid inlet bypass and the second liquid inlet bypass are respectively connected to the third liquid inlet pipe, and the first liquid inlet bypass and the second liquid inlet bypass are arranged on the side close to the discharge inlet, wherein the first liquid inlet bypass is provided with a first filter, and the second liquid inlet bypass is provided with a second filter.

[0006] In a feasible embodiment, the third liquid inlet pipe is provided with a first pressure switch and a second pressure switch, the first pressure switch is provided on the bypass inlet side of the first liquid inlet bypass and the second liquid inlet bypass, and the second pressure switch is provided on the bypass outlet side of the first liquid inlet bypass and the second liquid inlet bypass.

[0007] In a feasible embodiment, the first filter is provided with a first waste discharge pipeline, and a first filter waste discharge valve is provided on the first waste discharge pipeline; the second filter is provided with a second waste discharge pipeline, and a second filter waste discharge valve is provided on the second waste discharge pipeline.

[0008] In a feasible embodiment, the first filter is provided with a first flushing pipeline, and a first filter flushing valve is provided on the first flushing pipeline; the second filter is provided with a second flushing pipeline, and a second filter flushing valve is provided on the second flushing pipeline.

[0009] In a feasible embodiment, a density meter, a thermometer and a sampling valve are provided on the outer side wall of the circulation tank, and the sampling valve is provided on a side of the circulation tank close to the bottom.

[0010] In a feasible implementation manner, a shut-off valve is provided on the third liquid inlet pipe between the first liquid inlet bypass and the second liquid inlet bypass.

[0011] In a feasible implementation manner, a coating liquid flow meter is provided on the third liquid inlet pipe.

[0012] In a feasible embodiment, the third liquid inlet pipe is provided with a liquid supply pipe waste valve and a control valve, and the control valve is provided on a side close to the liquid discharge outlet.

[0013] In a feasible embodiment, the cooling device is provided with a cooling water supply pipe and a cooling water drain pipe, the cooling water supply pipe is provided with a cooling water control valve, and the cooling water drain pipe is provided with a cooling water flow meter.

[0014] Compared with the prior art, the present disclosure has at least the following beneficial effects: the present disclosure can achieve stable liquid supply and liquid return of high-viscosity, high-solid content, and high-density coating liquids, and can automatically adjust the delivery amount of the coating liquid, thereby improving the stability and uniformity of roller coating, and can stably deliver high-viscosity, high-solid content, and high-density coating liquids; a liquid return pump is provided on the coating machine liquid return pipeline to assist the coating liquid in returning to the circulation tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0016] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0017] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the exemplary embodiments below. The accompanying drawings are for illustration purposes only and are not to be considered limiting of the present application. Throughout the accompanying drawings, the same reference symbols denote the same components. In the accompanying drawings:

[0018] Figure 1 It is a structural diagram of the present disclosure.

[0019] in, Figure 1 The corresponding relationship between the reference numerals and component names is as follows:

[0020] 100-coating machine; 200-first liquid inlet pipe; 300-second liquid inlet pipe; 400-third liquid inlet pipe; 500-return liquid pipe; 600-return liquid bypass; 700-cooling device; 800-first liquid inlet bypass; 900-second liquid inlet bypass;

[0021] 1-cleaning ball; 2-agitator; 3-circulation tank; 4-thermometer; 5-sampling valve; 9-refrigerated water flowmeter; 10-refrigerated water control valve; 11-first delivery pump; 12-second delivery pump; 13-first pressure switch; 15-first filter drain valve; 16-second filter drain valve; 17-first filter; 18-first filter flushing valve; 19-second filter; 20-second filter flushing valve; 21-second pressure switch; 22-liquid supply pipe drain valve; 23-coating liquid flowmeter; 24-control valve; 26-stop valve; 27-liquid return pump; 29-liquid return valve; 31-density meter. DETAILED DESCRIPTION

[0022] In order to more clearly understand the above-mentioned objectives, features and advantages of the present disclosure, the scheme of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features therein can be combined with each other in the absence of conflict.

[0023] In the following description, many specific details are set forth to facilitate a full understanding of the present disclosure, but the present disclosure may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present disclosure, rather than all of the embodiments.

[0024] Currently, the coating process in a continuous annealing unit involves first applying a coating liquid to the strip surface via a coating machine, followed by drying and curing in a drying furnace, thereby forming an insulating coating on the strip surface. With technological advancements and growing environmental awareness, the requirements for the strip's insulation performance and environmental protection are becoming increasingly stringent. Consequently, the use of environmentally friendly coatings in continuous annealing units is becoming increasingly widespread. However, environmentally friendly coatings are high-viscosity, high-solids, high-density, and somewhat corrosive fluids with poor fluidity. The C6 environmentally friendly coating has the worst fluidity, with a maximum viscosity of approximately 5000 cP, a maximum solids content of approximately 78%, and a maximum density of approximately 1.9 g / ml. Existing coating circulation systems using diaphragm pumps are no longer able to continuously and stably deliver the C6 environmentally friendly coating to the coating machine. Furthermore, relying solely on gravity return is also extremely difficult, resulting in the coating machine being unable to properly roll coat. In addition, different strip steel products require different types of coating liquids, and the physical properties of various coating liquids vary greatly, which also have different impacts on the delivery capacity of the delivery pump. Therefore, each time the coating liquid type is switched, the coating liquid flow rate needs to be manually adjusted. However, the manually adjusted flow rate error is large, resulting in poor stability and uniformity of roller coating.

[0025] Based on this, the embodiment of the present disclosure provides a coating liquid circulation system for a continuous retreat unit. The present disclosure can achieve stable liquid supply and return of high-viscosity, high-solid content, and high-density coating liquids, and can automatically adjust the delivery amount of the coating liquid, thereby improving the stability and uniformity of roller coating, and can stably deliver high-viscosity, high-solid content, and high-density coating liquids; a return liquid pump is arranged on the coating machine return liquid pipeline to assist the coating liquid in returning to the circulation tank.

[0026] The coating liquid circulation system of the continuous annealing unit is described in detail below through a specific embodiment:

[0027] Reference Figure 1As shown, the present disclosure provides a coating liquid circulation system for a continuous annealing unit, including a coating machine 100, a circulation tank 3 and a pipeline assembly, the pipeline assembly including a first liquid inlet pipe 200, a second liquid inlet pipe 300, a third liquid inlet pipe 400, a return liquid pipe 500 and a return liquid bypass passage 600, one end of the return liquid pipe 500 is connected to the discharge port of the coating machine 100, and the other end thereof is connected to the liquid inlet of the circulation tank 3, and a return liquid valve 29 is provided on the side of the return liquid pipe 500 close to the circulation tank 3, one end of the first liquid inlet pipe 200 and the second liquid inlet pipe 300 are connected in parallel to the discharge port of the circulation tank 3, and the other end thereof is connected in parallel to the third liquid inlet pipe 40 0, the discharge outlet of the third liquid inlet pipe 400 is connected to the liquid replenishing port of the coating machine 100, the first liquid inlet pipe 200 is provided with a first delivery pump 11, and the second liquid inlet pipe 300 is provided with a second delivery pump 12; the two ends of the return liquid bypass passage 600 are respectively connected to the return liquid pipe 500, and the return liquid bypass passage 600 is provided with a return liquid pump 27, the circulation tank 3 includes a tank body, a cleaning ball 1, an agitator 2 and a cooling device 700, the cleaning ball 1 and the agitator 2 are arranged inside the circulation tank 3, and the cleaning ball 1 is arranged on the side of the circulation tank 3 near the top, and the cooling device 700 is used to cool the coating liquid in the circulation tank 3.

[0028] The first delivery pump 11 and the second delivery pump 12 of the present disclosure deliver the coating liquid to the spray beam of the coating machine 100. A portion of the coating liquid is sprayed onto the steel strip through the nozzle on the spray beam, and a portion of the coating liquid enters the coating machine's liquid receiving tray through the guide groove under the spray beam. The coating machine's liquid pickup roller dips the coating liquid in the liquid receiving tray, and then adjusts the appropriate amount of coating liquid on the liquid pickup roller through the metering roller. The coating liquid attached to the surface of the liquid pickup roller is then transferred to the coating roller to coat the surface of the steel strip. If the liquid level of the liquid receiving tray is too low, the pickup roller will dip too little (or even no) coating liquid, resulting in too little coating liquid on the coating roller, affecting the coating effect; if the liquid level of the liquid receiving tray is too high, the pickup roller will dip too much coating liquid, which will exceed the capacity of the metering roller, resulting in too much coating liquid on the coating roller, affecting the coating effect; in addition, since the coating liquid is corrosive to a certain extent, it is also necessary to prevent the coating liquid in the coating machine's liquid receiving tray from overflowing, so the circulation of the coating liquid in the coating machine is particularly important.

[0029] The second delivery pump 12 and the first delivery pump 11 of the present invention serve as backup for each other, forming two sets of liquid inlet pipelines for coating machines. The two liquid inlet pipelines can be fed with liquid at the same time or one of them can be fed with liquid selectively, which greatly improves the online time of the circulation system. The two ends of the return liquid bypass passage 600 are respectively connected to the return liquid pipe 500, and a return liquid pump 27 is provided on the return liquid bypass passage 600. The return liquid pump 27 is used to assist the high-viscosity coating liquid to return to the circulation tank 3; and the return liquid pump 27 is interlocked with the coating liquid flow meter and the coating machine liquid level meter 34 of the coating machine. Under normal circumstances, the flow rate of the return liquid pump 27 is set and corrected based on the liquid supply flow rate detected by the coating liquid flow meter to ensure the balance between liquid supply and return liquid. However, when the coating machine liquid level meter detects that the liquid level of the coating machine receiving tray is too high or too low, the return liquid pump 27 will increase or decrease the flow rate to ensure that the liquid level of the coating machine receiving tray is within the normal range, thereby ensuring the stability of the entire circulation system. The cooling device 700 of the present disclosure is used to cool the side walls and the bottom to prevent the coating liquid in the circulation tank 3 from deteriorating.

[0030] In some embodiments, a first liquid inlet bypass 800 and a second liquid inlet bypass 900 are further included. The first liquid inlet bypass 800 and the second liquid inlet bypass 900 are arranged opposite to each other, and the two ends of the first liquid inlet bypass 800 and the second liquid inlet bypass 900 are respectively connected to the third liquid inlet pipe 400, and the first liquid inlet bypass 800 and the second liquid inlet bypass 900 are arranged on the side close to the drainage inlet, wherein a first filter 17 is provided on the first liquid inlet bypass 800, and a second filter 19 is provided on the second liquid inlet bypass 900.

[0031] In this embodiment, the dual filters are arranged in parallel, enabling uninterrupted switching operation. While one filter set is undergoing maintenance, the other can maintain continuous system operation. The alternating channel design creates turbulent flow during the filtration process, enhancing impurity removal. The alternating trapezoidal and square cross-sections in the flow channel structure extend media retention time and improve filtration accuracy. This design is particularly suitable for continuous production conditions, and its modular structure allows for individual filter unit replacement without affecting overall system operation.

[0032] In some embodiments, the third liquid inlet pipe 400 is provided with a first pressure switch 13 and a second pressure switch 21, the first pressure switch 13 is provided on the bypass inlet side of the first liquid inlet bypass 800 and the second liquid inlet bypass 900, and the second pressure switch 21 is provided on the bypass outlet side of the first liquid inlet bypass 800 and the second liquid inlet bypass 900.

[0033] In this embodiment, the filter pressure drop is accurately calculated through real-time comparison between the first pressure switch 13 and the second pressure switch 21. Specifically, the first pressure switch 13 and the second pressure switch 21 can be T25 diaphragm pressure switches. The T25 diaphragm pressure switch uses a silicon piezoresistive diaphragm oil-filled core as the sensitive measuring element, has a G1 / 2 interface, is made of 316L, and is suitable for acidic coating liquids and high-viscosity acidic coating liquids. The measuring range is 0-1 MPa, with an accuracy of ±0.5% FS. The power supply is 24 VDC, the output is 4-20 mA + 2-way switch, the mounting method is G1 / 2, the electrical interface is an M12 waterproof plug, the liquid contact material is 316L, and it comes with a welded base and sealing ring.

[0034] In some embodiments, the first filter 17 is provided with a first waste pipe, and the first waste pipe is provided with a first filter waste valve 15; the second filter 19 is provided with a second waste pipe, and the second waste pipe is provided with a second filter waste valve 16.

[0035] In this embodiment, the first and second filters 17, 19 are equipped with independent waste valves, which can be precisely opened and closed by electromagnetic / pneumatic actuators, with a wastewater discharge response time of ≤0.5 seconds. These valves utilize stainless steel ball valves with a pressure rating of PN16, capable of handling corrosive media containing solid particles. The dual-line parallel architecture ensures that the system can still drain properly even if a single line fails, preventing excessive pressure loss due to filter clogging and reducing the risk of unplanned downtime.

[0036] In some embodiments, the first filter 17 is provided with a first flushing pipeline, and a first filter flushing valve 18 is provided on the first flushing pipeline; the second filter 19 is provided with a second flushing pipeline, and a second filter flushing valve 20 is provided on the second flushing pipeline.

[0037] In this embodiment, the first filter 17 and the second filter 19 are equipped with independent flushing valves, which are controlled by a PLC to achieve alternating backwashing. When the differential pressure sensor detects a resistance greater than 0.2 MPa, the corresponding valve is triggered to open, using system pressure to reversely flush the filter element, achieving a removal rate of up to 95%. The flushing water is discharged through independent pipelines to avoid cross contamination. The dual-system redundant design allows one filter to maintain normal flow output while the other filter is offline for cleaning. In conjunction with the first filter waste valve 15 and the second filter waste valve 16, a fully automatic waste discharge and flushing cycle can be achieved.

[0038] In some embodiments, a density meter 31 , a thermometer 4 and a sampling valve 5 are provided on the outer side wall of the circulation tank 3 , and the sampling valve 5 is provided on a side of the circulation tank 3 close to the bottom.

[0039] In this embodiment, the density meter 31 and the thermometer 4 are combined to synchronously obtain the density and temperature of the medium, providing a dual-parameter basis for process adjustment. The sampling valve 5 close to the bottom of the circulation tank 3 ensures that a representative bottom medium sample is obtained to avoid stratification errors. Specifically, the sampling valve 5 can adopt a flange connection structure with a pressure rating of ≥PN16 and a leakage rate of <0.001%. In terms of specific layout, the density meter 31 and the thermometer 4 should be spaced ≥300mm to avoid electromagnetic interference. The height of the center line of the sampling valve 5 from the bottom of the tank is 1 / 10 of the diameter of the tank body to ensure that the medium above the sedimentary layer is obtained, and the sampling valve 5 is installed at an inclination angle of 10° to 20° downward to facilitate the discharge of residual medium. This embodiment achieves precise monitoring of process parameters by optimizing the layout of detection points.

[0040] In some embodiments, a shut-off valve 26 is provided on the third liquid inlet pipe 400 between the first liquid inlet bypass 800 and the second liquid inlet bypass 900 .

[0041] In this embodiment, shutoff valve 26 forms an independent control node on third liquid inlet pipe 400. When the first liquid inlet bypass 800 or the second liquid inlet bypass 900 fails, the system can quickly switch to the backup pipeline. The system switching time is ≤ 30 seconds, improving system availability. This embodiment uses the high-reliability shutoff valve 26 to achieve rapid redundant switching of the pipeline system.

[0042] In some embodiments, a coating liquid flow meter 23 is provided on the third liquid inlet pipe 400 .

[0043] In this embodiment, a coating liquid flow meter 23 is provided on the third liquid inlet pipe 400. The coating liquid flow meter 23 monitors the flow of the main line in real time (accuracy ±0.5%) and feeds back the 4-20mA signal to the PLC system to achieve closed-loop control of the liquid supply volume and the coating machine speed.

[0044] In some embodiments, the third liquid inlet pipe 400 is provided with a liquid supply pipe waste valve 22 and a control valve 24 , and the control valve 24 is provided on a side close to the liquid discharge outlet.

[0045] In this embodiment, the third liquid inlet pipe 400 of the present disclosure is provided with a liquid supply pipe waste valve 22 and a control valve 24. The control valve 24 serves as a terminal flow regulating unit. Its installation near the outlet can achieve precise control of the outlet pressure (regulation accuracy ±0.05MPa), avoiding the pressure fluctuation at the end of the pipeline affecting the downstream equipment. The synergistic function of the waste valve 22 forms a dual-valve group structure with the control valve 24, which can isolate the medium and drain the residual liquid in the pipe section during system maintenance. Specifically, the installation of the control valve 24 on the outlet side shortens the adjustment response time (≤1 second), making flow control more timely. The control valve 24 is equipped with a pneumatic actuator to support remote emergency shut-off and flow control.

[0046] In some embodiments, the cooling device is provided with a cooling water supply pipe and a cooling water drain pipe. The cooling water supply pipe is provided with a cooling water control valve 10, and the cooling water drain pipe is provided with a cooling water flow meter 9.

[0047] In this embodiment, the cooling water control valve 10 serves as a dynamic adjustment unit for the cooling water supply pipe. It precisely controls the cooling water flow rate via a pneumatic actuator (with an adjustment accuracy of ±0.5%), ensuring that the heat exchanger inlet pressure remains stable within the range of 0.3-0.5 MPa. The monitoring function of the cooling water flow meter 9 provides real-time feedback on the actual heat exchange rate in the drain pipe, providing data support for energy efficiency optimization. The cooling water flow meter 9 and the cooling water control valve 10 form a closed-loop regulation system, dynamically matching the cooling water flow rate to the equipment heat load (with a temperature differential control accuracy of ±0.5°C). This embodiment utilizes a "monitoring-adjustment" linkage mechanism to achieve optimal energy consumption while ensuring cooling efficiency. Specifically, the cooling device 700 should be selected based on the specific heat capacity of the coating liquid and the circulation flow rate, depending on the cooling requirements of the circulating tank 3. A bottom coil and sidewall jacket cooling method can be used to cool the bottom and sidewalls of the circulating tank 3. The bottom coil and sidewall jacket should preferably adopt a zoned temperature control design with a temperature differential control accuracy of ±1°C. Among them, the bottom coil can be made of spiral titanium tube with a diameter of DN50-DN80 and a flow rate of 0.8-1.2m / s to prevent precipitation; the side wall jacket can be made of a honeycomb plate structure (flow channel height 15-20mm), laser welded with 316L stainless steel, and a pressure bearing capacity of ≥0.6MPa.

[0048] In the present disclosure, the terms "first", "second", and "third" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance; the term "plurality" refers to two or more, unless otherwise expressly defined. Terms such as "installed", "connected", "connected", and "fixed" should be understood in a broad sense. For example, "connected" can mean a fixed connection, a detachable connection, or an integral connection; "connected" can mean a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in the present disclosure can be understood according to the specific circumstances.

[0049] In the description of the present disclosure, it is to be understood that the terms "up", "down", "left", "right", "front", "back", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific direction, and therefore, cannot be understood as a limitation on the present disclosure.

[0050] Throughout this specification, terms such as "one embodiment," "some embodiments," and "specific embodiments" mean that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0051] The above are merely preferred embodiments of the present disclosure and are not intended to limit the present disclosure. Those skilled in the art will readily appreciate that various modifications and variations of the present disclosure are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present disclosure shall be included within the scope of protection of the present disclosure.

Claims

1. A coating liquid circulation system for a continuous annealing unit, characterized in that: The pipe assembly includes a first liquid inlet pipe, a second liquid inlet pipe, a third liquid inlet pipe, a liquid return pipe and a liquid return bypass passage, one end of the liquid return pipe is connected to the liquid discharge port of the coating machine, and the other end thereof is connected to the liquid inlet of the circulation tank, and a liquid return valve is provided on the liquid return pipe close to the circulation tank, one end of the first liquid inlet pipe and the second liquid inlet pipe are connected in parallel to the liquid discharge port of the circulation tank, and the other end thereof is connected in parallel to the liquid discharge inlet of the third liquid inlet pipe, the liquid discharge outlet of the third liquid inlet pipe is connected to the liquid replenishing port of the coating machine, a first delivery pump is provided on the first liquid inlet pipe, and a second delivery pump is provided on the second liquid inlet pipe; both ends of the liquid return bypass passage are respectively connected to the liquid return pipe, and a liquid return pump is provided on the liquid return bypass passage, wherein, The circulation tank includes a tank body, a cleaning ball, an agitator and a cooling device. The cleaning ball and the agitator are arranged inside the circulation tank, and the cleaning ball is arranged on the side of the circulation tank close to the top. The cooling device is used to cool the coating liquid in the circulation tank.

2. The coating liquid circulation system of the continuous annealing unit according to claim 1 is characterized in that: The first liquid inlet bypass and the second liquid inlet bypass are arranged opposite to each other, and both ends of the first liquid inlet bypass and the second liquid inlet bypass are respectively connected to the third liquid inlet pipe, and the first liquid inlet bypass and the second liquid inlet bypass are arranged on a side close to the liquid discharge inlet, wherein, A first filter is provided on the first liquid inlet bypass, and a second filter is provided on the second liquid inlet bypass.

3. The coating liquid circulation system of the continuous annealing unit according to claim 2, characterized in that: The third liquid inlet pipe is provided with a first pressure switch and a second pressure switch, the first pressure switch is provided on the bypass inlet side of the first liquid inlet bypass and the second liquid inlet bypass, and the second pressure switch is provided on the bypass outlet side of the first liquid inlet bypass and the second liquid inlet bypass.

4. The coating liquid circulation system of the continuous annealing unit according to claim 2, characterized in that: The first filter is provided with a first waste discharge pipeline, and a first filter waste discharge valve is provided on the first waste discharge pipeline; the second filter is provided with a second waste discharge pipeline, and a second filter waste discharge valve is provided on the second waste discharge pipeline.

5. The coating liquid circulation system of the continuous annealing unit according to claim 1, characterized in that: The first filter is provided with a first flushing pipeline, and a first filter flushing valve is provided on the first flushing pipeline; the second filter is provided with a second flushing pipeline, and a second filter flushing valve is provided on the second flushing pipeline.

6. The coating liquid circulation system of the continuous annealing unit according to claim 1, characterized in that: A density meter, a thermometer and a sampling valve are arranged on the outer side wall of the circulation tank, and the sampling valve is arranged on one side of the circulation tank close to the bottom.

7. The coating liquid circulation system of the continuous annealing unit according to claim 1, characterized in that: A shut-off valve is provided on the third liquid inlet pipe between the first liquid inlet bypass and the second liquid inlet bypass.

8. The coating liquid circulation system of the continuous annealing unit according to claim 1, characterized in that: The third liquid inlet pipe is provided with a coating liquid flow meter.

9. The coating liquid circulation system of the continuous annealing unit according to claim 1, characterized in that: The third liquid inlet pipe is provided with a liquid supply pipe waste valve and a control valve, and the control valve is provided on a side close to the liquid discharge outlet.

10. The coating liquid circulation system of the continuous annealing unit according to claim 1, characterized in that: The cooling device is provided with a cooling water supply pipe and a cooling water drain pipe. The cooling water supply pipe is provided with a cooling water control valve, and the cooling water drain pipe is provided with a cooling water flow meter.

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