Method and device for improving coating liquid supply stability

Abstract

The invention provides a method for improving the stability of coating liquid supply, which shortens the time from starting a pump to reaching the pressure stable state of the internal pressure of a liquid supply system and slowing down the pressure stable state to normal pressure when the pump is stopped, so as to improve the film thickness uniformity at the coating starting position and the problems of liquid accumulation at the coating tail end and liquid dripping at the coating end position. Liquid in the liquid supply container flows into the coating head through the liquid supply pump and the coating head liquid inlet pipe, a circulation stop valve is arranged at the feeding position of the coating head, the circulation stop valve is immediately opened after coating is finished, so that the liquid is prevented from flowing into the coating head, a liquid return pipe is further arranged on the upper portion of the circulation stop valve, and the liquid return pipe is communicated with the circulation stop valve. A backflow switch valve is arranged at the starting end of the liquid return pipe, the liquid return pipe enables liquid in a liquid inlet pipe of the coating head to flow back into the liquid supply container, a liquid outlet switch valve is further arranged at the liquid inlet end of the circulation stop valve, and the liquid outlet switch valve is used for supplying liquid to the coating head in the open state; the liquid outlet switch valve and the backflow switch valve are not opened at the same time.

Description

A method and apparatus for improving the stability of coating liquid supply Technical Field

[0001] This invention relates to the technical field of coating liquid supply, specifically to a method for improving the stability of coating liquid supply. This invention also provides an apparatus for improving the stability of coating liquid supply. Background Technology

[0002] The stability of the coating supply system is a key factor in coating technology, significantly impacting film formation and thickness uniformity. This is especially true for sheet coating equipment with vertically downward-facing coating nozzles, which features small coating area, relatively low flow rate, short coating time, and frequent pump start-up and shutdown. Consequently, the stability of the supply system has a substantial influence on film thickness uniformity at the beginning and end of coating, as well as on liquid accumulation or dripping at the coating tip.

[0003] The stability of the existing liquid supply system affects the uniformity of the coating thickness. Currently, the existing technology mainly improves the problem of liquid supply stability at both the beginning and end of the coating process when coating sheets by means of the following methods: (1) Install a pre-coating station and a pass-coating station before and after the sample sheet, respectively. The coating head starts coating from the pre-coating station and ends at the pass-coating station to offset the influence at the beginning and end of the liquid supply. The biggest problem with this method is that it is difficult to control the gaps between the pre-coating station and the sample sheet, and between the pass-coating station and the sample sheet. The solution can easily seep from the gaps to the back of the sample sheet, causing (1) Pollution, and this solution will also cause waste of coating solution due to the increased coating area; (2) Install a back suction device at the end of coating, and when coating is stopped, the coating liquid will be back sucked from the lip of the coating head to improve the problem of excessive solution caused by the pressure release of the liquid supply system at the end and the residual liquid between the coating head and the substrate. This method can improve the problem of liquid accumulation at the end of coating, but back suction is easy to suck air into the coating head and the lip of the coating head. If the solution is contaminated, it is easy to contaminate the solution inside the coating head. At the same time, it cannot solve the problem of unstable liquid supply at the beginning of coating.

[0004] Therefore, there is an urgent need to develop a method to improve the stability of the coating liquid supply, thereby ensuring that the liquid supply to the coating head can be stable and reliable during the coating process. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a method for improving the stability of coating liquid supply. This method shortens the time from pump start-up to the internal pressure of the liquid supply system reaching a stable state and the time when the pressure stabilizes and then returns to normal pressure after pump stop-up. This improves the uniformity of film thickness at the beginning of coating and addresses the issues of liquid accumulation and dripping at the end of coating.

[0006] A method for improving the stability of coating liquid supply is characterized by: liquid in a supply container flowing into the coating head through a supply pump and a coating head inlet pipe; a flow-stop valve is installed at the inlet position of the coating head, which opens immediately after coating to cut off the flow of liquid into the coating head; a return pipe is also installed above the flow-stop valve, and a reflux switch valve is installed at the beginning of the return pipe; the return pipe returns the liquid in the coating head inlet pipe to the supply container; and an outlet switch valve is also installed at the inlet end of the flow-stop valve. The liquid outlet valve is used to supply liquid to the coating head when it is open. The liquid outlet valve and the reflux valve are not open at the same time. At the beginning of the coating process, the liquid outlet valve is closed and the reflux valve is open. When the return pipe flows smoothly back, the liquid pressure in the coating head inlet pipe is sufficient. At this time, the reflux valve is closed and the liquid outlet valve and the flow stop valve are opened, so that the liquid enters the coating head for coating under stable pressure. At the end of the coating process, the flow stop valve is closed, the liquid outlet valve is closed and the reflux valve is open, and the liquid in the coating head inlet pipe flows back to the liquid supply container.

[0007] A further feature is that: the return end of the return pipe is integrated with a sensing device, which is externally connected to a valve controller. During the initial coating stage, the outlet valve is closed and the return valve is open. When the sensing device senses the liquid at the return end of the return pipe, that is, when the liquid pressure in the coating head inlet pipe is sufficient, the sensing device sends a signal to the valve controller. The valve controller controls the return valve to close and opens the outlet valve and the flow stop valve. When the valve controller receives the coating end signal, it drives the flow stop valve to close, the outlet valve to close, and the return valve to open, so that the liquid in the coating head inlet pipe flows back to the supply container. Preferably, the return end of the return pipe flows into the top of the supply container. The bottom of the supply container is externally connected to a pump inlet pipe and then connected to the input end of the coating head inlet pipe through a supply pump.

[0008] An apparatus for improving the stability of coating liquid supply, characterized in that it comprises: a liquid supply container; a liquid supply pump; a three-way liquid valve, which includes an inlet, an outlet, and a return port, wherein the three-way liquid valve is switched to connect the inlet to the outlet or the return port; a flow-stop valve; and a coating head; wherein the liquid supply container is connected to the inlet of the liquid supply pump through a pump inlet pipe, the outlet of the liquid supply pump is connected to the inlet of the three-way liquid pump through a coating head inlet pipe, the flow-stop valve is provided between the outlet and the inlet of the coating head, and the return port is connected to the liquid supply container through a return pipe.

[0009] Its further features are as follows: the three-way liquid valve integrates the functions of a liquid outlet switch valve and a return switch valve, simplifying the pipeline layout and ensuring reliable switching; the flow stop valve is a pneumatic diaphragm valve, which shortens the reaction time of liquid cut-off, reduces the impact on the liquid outlet of the coating head, reduces the liquid accumulation at the tail end at the end of coating, and prevents dripping when the coating head is lifted; the internal pressure relief of the liquid supply section from the liquid supply container to the three-way liquid valve allows the solution to return to the liquid supply container through the return port of the three-way liquid valve; preferably, the return end of the return pipe flows into the top of the liquid supply container; the bottom of the liquid supply container is connected to the external pump inlet pipe and then connected to the input end of the coating head inlet pipe through the liquid supply pump.

[0010] With this invention, at the initial stage of coating, the liquid outlet valve is closed and the reflux valve is open. When the return pipe flows smoothly back, the liquid pressure in the coating head inlet pipe is sufficient. At this time, the reflux valve is closed, and the liquid outlet valve and the flow stop valve are opened, allowing the liquid to enter the coating head for coating under stable pressure. At the end of coating, the liquid supply pump is closed, the flow stop valve is closed, the liquid outlet valve is closed, and the reflux valve is open. The liquid in the coating head inlet pipe flows back to the liquid supply container through internal pressure. This shortens the time from pump start-up to the internal pressure of the liquid supply system reaching a stable pressure state and the time for the pressure to slow down to normal pressure when the pump is stopped, thereby improving the uniformity of film thickness at the beginning of coating and the problems of liquid accumulation and dripping at the end of coating. Attached Figure Description

[0011] Figure 1 is a simplified structural diagram of the device for improving the stability of coating liquid supply according to the present invention; the names corresponding to the serial numbers in the figure are as follows: liquid supply container 1, pump inlet pipe 2, liquid supply pump 3, coating head inlet pipe 4, three-way liquid valve 5, liquid inlet 6, liquid outlet 7, liquid return port 8, pneumatic diaphragm valve 9, coating head 10, liquid return pipe 11. Detailed Implementation

[0012] A method for improving the stability of coating liquid supply: Liquid in the supply container flows into the coating head through a supply pump and the coating head inlet pipe. A flow-stop valve is installed at the inlet position of the coating head. The flow-stop valve opens immediately after coating to cut off the liquid flow into the coating head. A return pipe is also installed above the flow-stop valve. A reflux switch valve is installed at the beginning of the return pipe. The return pipe returns the liquid in the coating head inlet pipe back to the supply container. An outlet switch valve is also installed at the inlet end of the flow-stop valve. The outlet switch valve opens... In this state, it is used to supply liquid to the coating head; the liquid outlet switch valve and the reflux switch valve are not open at the same time; at the beginning of the coating process, the liquid outlet switch valve is closed and the reflux switch valve is open. When the return pipe flows back smoothly, the liquid pressure in the coating head inlet pipe is sufficient. At this time, the reflux switch valve is closed, and the liquid outlet switch valve and the flow stop valve are opened, so that the liquid enters the coating head for coating under stable pressure; at the end of the coating process, the flow stop valve is closed, the liquid outlet switch valve is closed, and the reflux switch valve is open, and the liquid in the coating head inlet pipe flows back to the liquid supply container.

[0013] In the preferred embodiment, a sensing device is integrated at the reflux end of the return pipe, and the sensing device is externally connected to a valve controller. At the beginning of the coating process, the outlet valve is closed and the reflux valve is open. When the sensing device detects the liquid at the reflux end of the return pipe, that is, when the liquid pressure in the coating head inlet pipe is sufficient, the sensing device sends a signal to the valve controller. The valve controller controls the reflux valve to close and opens the outlet valve and the flow stop valve. When the valve controller receives the coating end signal, it immediately drives the flow stop valve to close, the outlet valve to close, and the reflux valve to open, so that the liquid in the coating head inlet pipe flows back to the supply container.

[0014] The device for improving the stability of coating liquid supply, as shown in Figure 1, includes a liquid supply container 1, a liquid supply pump 3, a three-way liquid valve 5, a flow stop valve, and a coating head 10. The three-way liquid valve 5 includes an inlet 6, an outlet 7, and a return port 8. The three-way liquid valve 5 can be switched so that the inlet 6 is connected to the outlet 7 or the return port 8. The liquid supply container 1 is connected to the inlet of the liquid supply pump 3 through the pump inlet pipe 2. The outlet of the liquid supply pump 3 is connected to the inlet 6 of the three-way liquid pump 5 through the coating head inlet pipe 4. A flow stop valve is provided between the outlet 7 and the inlet of the coating head 10. The return port 8 is connected to the liquid supply container 1 through the return pipe 11.

[0015] In practical implementation, the three-way liquid valve 5 integrates the functions of closing the liquid outlet switch valve and the return switch valve, which simplifies the pipeline layout and ensures reliable switching. The flow stop valve is specifically a pneumatic diaphragm valve 9, which shortens the reaction time of liquid cut-off, reduces the impact on the liquid outlet of the coating head 10, reduces the liquid accumulation phenomenon at the tail end at the end of coating, and prevents dripping when the coating head 10 is lifted. The internal pressure relief of the liquid supply section from the liquid supply container 1 to the three-way liquid valve 5 allows the solution to return to the liquid supply container 1 through the return port 8 of the three-way liquid valve 5.

[0016] In a specific embodiment, the liquid supply container 1 is a liquid supply tank; the return end of the return pipe 11 flows into the top of the liquid supply container 1 (liquid supply tank); the bottom of the liquid supply container 1 (liquid supply tank) is connected to the external pump inlet pipe 2 and then connected to the input end of the coating head inlet pipe 4 through the liquid supply pump 3.

[0017] The workflow is as follows: At the start of coating, the supply pump 3 draws solution from the supply container 1 via the pump inlet pipe 2, then through the coating head inlet pipe 4 to the three-way chemical valve 5. The three-way chemical valve 5 first forms a passage between the inlet port 6 and the return port 8, and then a closed loop between the inlet port 6 and the outlet port 7. The solution returns to the supply container 1 from the return port 8, thus ensuring a stable supply system from the supply container 1 to the three-way chemical valve. Then, the pneumatic diaphragm valve 9 is opened, creating a passage, while simultaneously switching the three-way chemical valve 5 to allow the solution to enter. Inlet 6 and outlet 8 form a closed loop, while inlet 6 and outlet 7 form a continuous loop. The solution is extruded through the coating head 10 to complete the coating process. At the end of coating, the pneumatic diaphragm valve is first closed to create a closed loop. Simultaneously, the three-way chemical valve is switched, creating a continuous loop between inlet 6 and outlet 8, and a closed loop between inlet 6 and outlet 7. This blocks the pressure within the supply system from supply container 1 to the three-way chemical valve 5, reducing the impact on the liquid output from the coating head 10, minimizing liquid accumulation at the end of coating, and preventing dripping when the coating head 10 is lifted. When the pressure within the supply system from supply container 1 to the three-way chemical valve 5 is released, the solution returns to supply container 1 through outlet 8.

[0018] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0019] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for improving the stability of coating liquid supply, characterized in that: Liquid from the supply container flows into the coating head via a supply pump and the coating head inlet pipe. A flow-stop valve is installed at the inlet position of the coating head. This valve opens immediately after coating to cut off the flow of liquid into the coating head. A return pipe is installed above the flow-stop valve, with a reflux switch valve at its starting end. The return pipe returns the liquid from the coating head inlet pipe back to the supply container. An outlet switch valve is also installed at the inlet end of the flow-stop valve. When the outlet switch valve is open... Used to supply liquid to the coating head; the liquid outlet valve and the reflux valve do not open simultaneously; at the beginning of coating, the liquid outlet valve is closed and the reflux valve is open. When the return pipe flows smoothly back, the liquid pressure in the coating head inlet pipe is sufficient. At this time, the reflux valve is closed, and the liquid outlet valve and the flow stop valve are opened, so that the liquid enters the coating head for coating under stable pressure; at the end of coating, the flow stop valve is closed, the liquid outlet valve is closed, and the reflux valve is open, and the liquid in the coating head inlet pipe flows back to the liquid supply container.

2. The method for improving coating liquid supply stability according to claim 1, characterized in that: The return end of the return pipe is integrated with a sensing device, which is externally connected to a valve controller. At the beginning of the coating process, the outlet valve is closed and the return valve is open. When the sensing device senses the liquid at the return end of the return pipe, that is, when the liquid pressure in the coating head inlet pipe is sufficient, the sensing device sends a signal to the valve controller. The valve controller controls the return valve to close and opens the outlet valve and the flow stop valve. When the valve controller receives the coating end signal, it drives the flow stop valve to close, the outlet valve to close, and the return valve to open, so that the liquid in the coating head inlet pipe flows back to the supply container.

3. The method for improving coating liquid supply stability according to claim 1, characterized in that: The return end of the return pipe flows into the top of the supply container.

4. The method for improving coating liquid supply stability according to claim 1, characterized in that: The liquid supply container is connected to the bottom of an external pump inlet pipe, which is then connected to the input end of the coating head inlet pipe via a liquid supply pump.

5. An apparatus for improving coating solution supply stability, used for performing a method for improving coating solution supply stability as described in any one of claims 1-4, characterized in that, It includes: liquid supply container; A liquid supply pump; a three-way liquid valve, including an inlet, an outlet, and a return port, wherein the three-way liquid valve can be switched to connect the inlet to the outlet or the return port; a flow-stop valve; and an applicator head; the liquid supply container is connected to the inlet of the liquid supply pump through a pump inlet pipe, the outlet of the liquid supply pump is connected to the inlet of the three-way liquid supply pump through an applicator head inlet pipe, the flow-stop valve is provided between the outlet and the inlet of the applicator head, and the return port is connected to the liquid supply container through a return pipe.

6. The apparatus for improving coating liquid supply stability according to claim 5, characterized in that: The three-way liquid valve integrates the functions of a liquid outlet switch valve and a reflux switch valve.

7. The apparatus for improving coating liquid supply stability according to claim 5, characterized in that: The flow shut-off valve is a pneumatic diaphragm valve.

8. The apparatus for improving coating liquid supply stability according to claim 5, characterized in that: The return end of the return pipe flows into the top of the supply container.

9. The apparatus for improving coating liquid supply stability according to claim 5, characterized in that: The liquid supply container is connected to the bottom of an external pump inlet pipe, which is then connected to the input end of the coating head inlet pipe via a liquid supply pump.

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