A solvent automatic circulation cleaning process

Abstract

The invention discloses a solvent automatic circulation cleaning process, step 1, placing a paint bucket: clamping the paint bucket in a protective cover, and the opening of the paint bucket faces downward; step 2, first flushing: opening the first control valve, extending the high-pressure nozzle into the paint bucket, starting the pump group, and the solvent is sprayed on the inner wall of the paint bucket in a solid umbrella shape through the high-pressure nozzle, and the paint in the paint bucket is high-pressure flushed, and the mixed liquid after flushing flows into the temporary storage tank along the inner wall of the paint bucket; step 3, circulation flushing: when the high liquid level switch on the top of the temporary storage tank is triggered, the first control valve is closed, the second control valve is opened, and the pump group transports the mixed liquid in the temporary storage tank to the high-pressure nozzle, and the paint bucket is circulated and flushed, and the mixed liquid after flushing still flows into the temporary storage tank. All pipelines are controlled by solenoid valves, without manual intervention, and the entire control process is controlled by PLC closed loop, with a high degree of automation.

Description

Technical Field

[0001] The invention relates to the field of paint bucket cleaning, in particular to an automatic solvent circulation cleaning process. Background Art

[0002] With the rapid development of various industries, the amount of paint used by a large number of equipment and facilities has also increased. Especially in the shipbuilding industry, the large-area multi-layer coating of the hull requires a large amount of paint, resulting in a large number of paint buckets to be handled;

[0003] In recent years, a method of cleaning paint barrels with solvents has appeared on the market. This method can not only clean the paint, but the recycled paint can also be used as an auxiliary material for ink printers, killing two birds with one stone;

[0004] The solvents currently on the market include acetone, ether or other blending solvents. Due to the lack of systematic process and data support, the solvents are used improperly. Although the paint is cleaned off, the solvent is wasted, and the wasted solvent even exceeds the value of cleaning the paint itself. Therefore, how to improve the efficiency of solvent use has become a problem that needs to be solved urgently.

[0005] At present, there are two ways to clean paint buckets with solvents. One is immersion, which is to immerse the paint bucket in solvent to dissolve the paint. The disadvantage of this immersion method is that the immersion time cannot be digitally managed. It can only be immersed for a long time to achieve the purpose of complete dissolution. However, for large agglomerated paint, there are dead corners where the paint is not fully dissolved, and the cleaning effect is not ideal.

[0006] The other is flushing, which involves manually flushing the paint in the barrel with a high-pressure spray gun. This type of flushing is cleaner than the immersion cleaning method, but repeated flushing results in a large amount of solvent waste, and the solvent utilization rate is relatively low. In addition, the labor intensity of the operator is high and the working environment is poor. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide an efficient circulating automatic cleaning process for cleaning paint buckets while improving the utilization rate of solvents in view of the deficiencies of the above-mentioned prior art.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0009] An automatic circulation cleaning process with efficient use of solvents, step 1, placing a paint bucket: clamping the paint bucket in a protective cover with the opening of the paint bucket facing downward; step 2, first flushing: opening a first control valve, extending a high-pressure nozzle into the paint bucket, starting a pump group, and spraying the solvent in a solid umbrella shape through the high-pressure nozzle onto the inner wall of the paint bucket, performing high-pressure flushing on the paint in the paint bucket, and the mixed liquid after flushing flows into a temporary storage tank along the inner wall of the paint bucket; step 3, circulation flushing: when a high liquid level switch on the top of the temporary storage tank is triggered, closing the first control valve, opening the second control valve, and the pump group transports the mixed liquid in the temporary storage tank to the high-pressure nozzle, circulates and flushes the paint bucket, and the mixed liquid after flushing still flows into the temporary storage tank.

[0010] As a further preferred embodiment of the present invention, step 4 of collecting the mixture is also included: when the mixed liquid in step 3 has a poor effect on flushing and dissolving the paint in the paint bucket, the second control valve is closed, the third control valve is opened, and the solvent and paint mixture in the temporary storage tank flows into the collection tank.

[0011] As a further preferred embodiment of the present invention, there are five high-pressure nozzles, which are evenly arranged around and on the top of the solvent outlet end, so that the solvent can be flushed to all angles in the paint bucket.

[0012] As a further preferred embodiment of the present invention, the spray angle of each high-pressure nozzle is a solid fan with a spray angle of 55°.

[0013] As a further preferred embodiment of the present invention, the working pressure of the high-pressure nozzle is 1.2 bar, and the flow rate is 22 L / min. Under the action of the centrifugal pump, the solvent passes through the high-pressure nozzle to produce a solid cone spray shape, and the spray area is circular.

[0014] As further preferred embodiment of the present invention, the solvent is ethyl acetate, n-butanol or anisole.

[0015] As a further preferred embodiment of the present invention, the solvent formula is 59% anisole, 12% N-methylpyrrolidone, and 24% 15% reduction accelerator solution.

[0016] As a further preferred embodiment of the present invention, the solvent tank, temporary storage tank and collection tank are all provided with low liquid level switches at the bottom and high liquid level switches at the top.

[0017] As a further preferred embodiment of the present invention, the first control valve, the second control valve and the third control valve are all solenoid valves, all pipelines are controlled by the solenoid valves, and the entire control process is controlled by PLC closed-loop control.

[0018] As a further preferred embodiment of the present invention, a weighing step is also included before step one, in which the paint bucket is weighed and compared with a bucket without paint to obtain the weight of the paint, which is transmitted to the PLC to control the number and duration of cleaning.

[0019] The present invention has the following beneficial effects:

[0020] Repeated high-pressure flushing without dead angles

[0021] This patent adopts high-pressure spraying to repeatedly flush the paint bucket without dead corners. It can quickly merge the paint and solvent in the bucket and quickly flush away the dissolved paint. This method is more effective than traditional hand-held flushing and greatly reduces labor intensity.

[0022] Fully automated closed-loop real-time control

[0023] All tanks are equipped with high and low level switches to monitor the liquid level in the tank to prevent the liquid from overflowing due to excessively high liquid level. At the same time, the low level switch is used to monitor the presence of liquid in the tank, to provide low level warning, and to avoid ineffective operation of the liquid and mixing of new and old liquids.

[0024] All pipelines are controlled by solenoid valves without manual intervention, and the entire control process is controlled by PLC closed loop with a high degree of automation.

[0025] Highly adaptable

[0026] This patented cleaning method is not only suitable for the small paint bucket shown in the figure, but also for large-sized paint buckets; at the same time, by changing the solvent, it can meet the timing and quantitative cleaning of different paints.

[0027] This patent can not only be operated as a single machine, but also can be used in conjunction with a weighing system to realize a digital management program and perform quantitative cleaning of the paint in the paint bucket. It can also be used in conjunction with robot handling to achieve automatic loading and unloading.

[0028] Safety and environmental protection

[0029] The flushing process is carried out in a closed space, which effectively avoids the volatilization and diffusion of solvents, greatly reduces the concentration of flammable and explosive substances, improves safety, and achieves environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0031] Figure 2 It is the front view of the high pressure nozzle arrangement;

[0032] Figure 3 It is a top view of the high-pressure nozzle arrangement. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific preferred embodiments.

[0034] In the description of the present invention, it should be understood that the terms "left side", "right side", "upper part", "lower part" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. "First", "second" and the like do not indicate the importance of the components, and therefore cannot be understood as limiting the present invention. The specific dimensions used in this embodiment are only for illustrating the technical solution, and do not limit the scope of protection of the present invention.

[0035] As shown in the figure, the automatic cleaning component includes a solvent tank, a collection tank, a temporary storage tank, a pump group, a high-pressure nozzle, a first control valve, a second control valve, a third control valve, a first pipeline, a second pipeline, a third pipeline and a fourth pipeline; the solvent tank is connected to the pump group through the first pipeline, the first control valve is arranged on the first pipeline, the temporary storage tank is arranged below the high-pressure nozzle, the temporary storage tank is connected to the pump group through the second pipeline, the second control valve is arranged on the second pipeline, the collection tank is connected to the temporary storage tank through the third pipeline, the third control valve is arranged on the third pipeline, and the high-pressure nozzle is connected to the pump group through the fourth pipeline. The solvent tank, the collection pipe and the temporary storage tank are all provided with liquid level switches.

[0036] In the initial state, the first control valve, the second control valve and the third control valve are all in the closed state, and the high liquid level switch of the solvent tank detects that the solvent tank is full of solvent. At this time, there is no liquid in the collection tank and the temporary storage tank, and the shield is in the open state.

[0037] During operation: the operator or manipulator places the paint bucket at the spraying position. After the equipment is started, the shield descends to clamp the paint bucket upside down.

[0038] The first control valve is opened, the pump group is started, and the solvent is sprayed on the inner wall of the barrel through the high-pressure nozzle in a solid umbrella shape, and the paint in the barrel is flushed with high pressure. The fan-shaped area of ​​the nozzle covers all the inner walls of the barrel and continuously flushes the inner walls. The flushed solvent enters the temporary storage tank.

[0039] Generally, after flushing multiple paint buckets, the liquid in the temporary storage tank will trigger the high liquid level switch. At this time, the first control valve is closed and the second control valve is opened. At this time, the liquid in the temporary storage tank is circulated through the pump group to repaint the bucket until the solvent has a poor effect on the paint in the bucket. At this time, the second control valve is closed, and the third control valve is opened to send the mixture of solvent and paint in the temporary storage tank to the collection tank.

[0040] Then the above process is repeated to achieve the purpose and effect of repeated circulation flushing of limited solvent.

[0041] This patent adopts high-pressure spraying to repeatedly flush the paint bucket without dead corners. It can quickly merge the paint and solvent in the bucket and quickly flush away the dissolved paint. This method is more effective than traditional hand-held flushing and greatly reduces labor intensity.

[0042] There are 5 nozzles in total, all of which are solid fan-shaped with a spray angle of 55°, a working pressure of 1.2 bar, and a flow rate of 22L / min. Under the action of the centrifugal pump, the solvent passes through the nozzle to produce a solid cone spray shape, and the spray area is circular. The nozzle can produce a uniformly distributed spray with medium to large droplet size under a wide range of flow rates and pressures. This uniform spray distribution comes from the unique blade design, large and unobstructed flow channel, and excellent control characteristics. The purpose of cleaning the paint in the barrel has been achieved by flushing the barrel in all directions without dead angles.

[0043] High solvent utilization circulation method

[0044] After a single flushing, if the solvent is discharged directly, a large amount of solvent will be wasted. The temporary storage tank will collect the underutilized solvent and re-enter the cleaning pipeline by switching the pipeline for cleaning new paint barrels. This circulating flushing method greatly improves the utilization rate of the solvent.

[0045] Generally, the utilization rate of a single cleaning solvent is only 5%-10%, that is, about 90% of the solvent does not fully dissolve the paint. By collecting the mixed liquid containing unused solvent and reusing it for washing and dissolving the paint, the utilization rate of the solvent can be maximized;

[0046] The experiment used n-butanol, ethyl acetate, formic acid, anisole and other different solvents to pre-soak the lid of the waste paint bucket. Ethyl acetate, n-butanol and anisole can complete the cleaning task, but anisole has more prominent swelling and dissolving effects and takes less time. Anisole is selected as the main solvent, and other solvents can also be used as additives in subsequent cleaning formulas.

[0047] Finally, the optimal formula of the compound solvent was determined: 59% anisole, 12% N-methylpyrrolidone, and 24% 15% reduction accelerator solution, which can achieve a cleaning efficiency of 99.5% for epoxy coatings of 100±15 μm.

[0048] All tanks are equipped with high and low level switches to monitor the liquid level in the tank to avoid liquid overflow due to excessively high liquid level. At the same time, the low level switch is used to monitor the presence of liquid in the tank, to provide low level warning, and to avoid ineffective operation of the liquid and the mixing of new and old liquids.

[0049] All pipelines are controlled by solenoid valves without manual intervention, and the entire control process is controlled by PLC closed loop with a high degree of automation.

[0050] This patented cleaning method is not only suitable for the small paint bucket shown in the figure, but also for large-sized paint buckets; at the same time, by changing the solvent, it can meet the timing and quantitative cleaning of different paints.

[0051] This patent can not only be operated as a single machine, but also can be used in conjunction with a weighing system to realize a digital management program and perform quantitative cleaning of the paint in the paint bucket. It can also be used in conjunction with robot handling to achieve automatic loading and unloading.

[0052] The flushing process is carried out in a closed space, which effectively avoids the volatilization and diffusion of solvents, greatly reduces the concentration of flammable and explosive substances, improves safety, and achieves environmental protection.

[0053] The preferred embodiments of the present invention are described in detail above; however, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all belong to the protection scope of the present invention.

Claims

1. A solvent automatic circulation cleaning process, which is implemented by an automatic cleaning component, the automatic cleaning component includes a solvent tank, a collection tank, a temporary storage tank, a pump group, a high-pressure nozzle, a first control valve, a second control valve, a third control valve, a first pipeline, a second pipeline, a third pipeline and a fourth pipeline; the solvent tank is connected to the pump group through a first pipeline, the first control valve is arranged on the first pipeline, the temporary storage tank is arranged below the high-pressure nozzle, the temporary storage tank is connected to the pump group through a second pipeline, the second control valve is arranged on the second pipeline, the collection tank is connected to the temporary storage tank through a third pipeline, the third control valve is arranged on the third pipeline, and the high-pressure nozzle is connected to the pump group through a fourth pipeline, characterized in that: Step 1: Place the paint bucket: Clamp the paint bucket in the protective cover with the opening of the paint bucket facing downwards; Step 2: First flushing: Open the first control valve, extend the high-pressure nozzle into the paint bucket, start the pump group, and the solvent is sprayed on the inner wall of the paint bucket in a solid umbrella shape through the high-pressure nozzle to perform high-pressure flushing on the paint in the paint bucket, and the mixed liquid after flushing flows into the temporary storage tank along the inner wall of the paint bucket; Step 3: Circular flushing: When the high liquid level switch on the top of the temporary storage tank is triggered, the first control valve is closed, the second control valve is opened, and the pump group transports the mixed liquid in the temporary storage tank to the high-pressure nozzle to circulate and flush the paint bucket. The mixed liquid after flushing still flows into the temporary storage tank; The invention also includes the step of collecting the mixture: when the mixed liquid in step 3 has a poor effect on washing and dissolving the paint in the paint bucket, the second control valve is closed, the third control valve is opened, and the solvent and paint mixture in the temporary storage tank flows into the collection tank; The solvent tank, temporary storage tank and collection tank are all equipped with low liquid level switches at the bottom and high liquid level switches at the top; The first control valve, the second control valve and the third control valve are all solenoid valves, all pipelines are controlled by solenoid valves, and the entire control process is controlled by PLC closed loop.

2. The solvent automatic circulation cleaning process according to claim 1, characterized in that: There are five high-pressure nozzles, which are evenly arranged around and on the top of the solvent outlet end of the fourth pipeline, so that the solvent can be flushed to all angles in the paint bucket.

3. The solvent automatic circulation cleaning process according to claim 2 is characterized in that: The spray angle of each high-pressure nozzle is a solid fan with a spray angle of 55°.

4. The solvent automatic circulation cleaning process according to claim 3 is characterized in that: The working pressure of the high-pressure nozzle is 1.2 bar and the flow rate is 22L / min. Under the action of the centrifugal pump, the solvent passes through the high-pressure nozzle to produce a solid cone spray shape, and the spray area is circular.

5. The solvent automatic circulation cleaning process according to claim 1 is characterized in that: The solvent is ethyl acetate, n-butanol or anisole.

6. The solvent automatic circulation cleaning process according to claim 1 is characterized in that: The solvent formula is 59% anisole, 12% N-methylpyrrolidone, and 24% 15% reduction accelerator solution.

7. The solvent automatic circulation cleaning process according to claim 1 is characterized in that: Before step one, a weighing step is also included, in which the paint bucket is weighed and compared with a bucket without paint to obtain the weight of the paint, which is transmitted to the PLC to control the number and duration of cleaning.

Images