Defoaming system and defoaming process of paint production process system

Abstract

This invention discloses a defoaming system and defoaming process for a coating production process, comprising a temporary buffer tank device (a), an intermittent vacuum centrifugal defoaming system, and a temporary buffer tank device (b). The discharge end of the temporary buffer tank device (a) is connected to the feed end of the intermittent vacuum centrifugal defoaming system, and the discharge end of the intermittent vacuum centrifugal defoaming system is connected to the feed end of the temporary buffer tank device (b). The intermittent vacuum centrifugal defoaming system includes a rotating cylinder with a central channel inside; it also includes an upper fixed pipe, a lower fixed pipe, and a centrifugal defoaming bottle; the lower end of the upper fixed pipe is coaxially connected to the upper end of the central channel via a rotary joint, and the upper end of the lower fixed pipe is coaxially connected to the lower end of the central channel via a rotary joint; the emulsion to be defoamed at the discharge end of the temporary buffer tank device (a) is bypassed and connected to the upper fixed pipe; the lower end of the lower fixed pipe is connected to the feed end of the temporary buffer tank device (b); thus achieving efficient removal of microbubbles from the coating emulsion.

Description

Technical Field

[0001] This invention belongs to the field of coating production. Background Technology

[0002] During the paint production process, after processes such as dispersion, grinding, and paint mixing, a large number of microbubbles are often incorporated into the paint emulsion. If these bubbles are not effectively removed before filling, they will affect the smoothness, gloss, and adhesion of the coating film, leading to quality defects such as pinholes and craters.

[0003] The defoaming treatment of existing coating production lines mainly adopts three methods: static defoaming, vacuum defoaming, and centrifugal defoaming.

[0004] Defoaming by letting the bubbles stand still relies on their own buoyancy to rise, which is time-consuming and not very effective for microbubbles.

[0005] Vacuum degassing reduces the pressure above the liquid surface, causing bubbles to expand and burst. However, in high-viscosity coatings, the resistance to bubble migration is high, resulting in limited degassing efficiency.

[0006] Centrifugal degassing utilizes density differences to cause bubbles to gather towards the center. However, in traditional centrifugal degassing equipment, the position of the coating relative to the centrifugal container is fixed during centrifugation, making it difficult for the coating's center of mass to deviate further from the center of rotation, thus limiting the effective enhancement of centrifugal force.

[0007] In addition, most existing equipment operates in batch mode, with feeding, degassing, and discharging processes being separate from each other, making it difficult to efficiently match with continuous coating production lines. Summary of the Invention

[0008] Purpose of the invention: In order to overcome the shortcomings of the existing technology, the present invention provides a defoaming system and defoaming process for a coating production process, which achieves efficient removal of micro bubbles in coating emulsions.

[0009] Technical Solution: To achieve the above objectives, the defoaming system of the coating production process system of the present invention includes a temporary buffer tank device, an intermittent vacuum centrifugal defoaming system, and a temporary buffer tank device. The discharge end of the temporary buffer tank device a is connected to the feed end of the intermittent vacuum centrifugal defoaming system, and the discharge end of the intermittent vacuum centrifugal defoaming system is connected to the feed end of the temporary buffer tank device b. The intermittent vacuum centrifugal defoaming system includes a rotating cylinder with a central channel inside; it also includes an upper fixed pipe, a lower fixed pipe, and a centrifugal defoaming bottle; the lower end of the upper fixed pipe is coaxially connected to the upper end of the central channel through a rotary joint. The upper end of the lower fixed pipe is coaxially connected to the lower end of the central channel via a rotary joint; the outlet pipe of the temporary buffer tank device (a) is connected to the upper fixed pipe via a bypass; the lower end of the lower fixed pipe is connected to the inlet end of the temporary buffer tank device (b); a bypass pipe extending downwards is integrally connected to one side of the lower section of the rotating cylinder, the bypass pipe contains a bypass channel, and the end of the bypass pipe is coaxially connected to the centrifugal defoaming bottle; a solenoid valve (a) is installed in the emulsion pipe to be defoamed, and a solenoid valve (b) is installed at the upper end of the upper fixed pipe. When solenoid valve (b) is turned on, the upper end of the upper fixed pipe is connected to atmospheric pressure; a solenoid valve (c) is installed at the upper end of the lower fixed pipe.

[0010] Furthermore, the upper end of the centrifugal defoaming bottle is coaxially connected to the lower end of the bypass pipe through a conical ring wall, and the tail end of the centrifugal defoaming bottle is integrally provided with a bottle bottom wall; a permanent magnet column is coaxially fixedly installed on the bottle bottom wall; a piston is coaxially movable inside the centrifugal defoaming bottle, and a spring chamber is between the piston and the bottle bottom wall; a thrust spring is coaxially installed in the spring chamber, and the thrust spring applies axial thrust to the piston; a magnetic block is fixedly installed on the side of the piston near the permanent magnet column, and when the distance between the permanent magnet column and the magnetic block is shortened to a certain extent, a significant magnetic attraction force is formed between the permanent magnet column and the magnetic block; the side of the piston away from the permanent magnet column is the defoaming chamber, and the connection between the defoaming chamber and the bypass channel is a conical transition section.

[0011] Furthermore, the bottom wall of the bottle has a perforated air pressure balance hole; the spring chamber is connected to the outside through the air pressure balance hole.

[0012] Furthermore, the centrifugal defoaming bottle includes positions "a", "b", "c", and "d" from top to bottom along the axial direction. When the rotating cylinder is stationary and the defoaming chamber is under atmospheric pressure, the thrust spring pushes the piston upward to position "a" and is limited by the conical ring wall. Position "b" is located in the middle section of the centrifugal defoaming bottle. When the piston is at position "c", a significant magnetic attraction is formed between the permanent magnet column and the magnetic block.

[0013] When the piston is at position "d", the permanent magnet column just makes contact with the magnetic block.

[0014] A distance sensor is installed on the inside of the bottle bottom wall. The distance sensor can monitor the distance between the bottle bottom wall and the piston, thereby enabling real-time knowledge of the piston's position.

[0015] Furthermore, it also includes a fixed bearing support, in which a vertical rotating cylinder is rotatably mounted via a bearing; a belt timing pulley is coaxially and synchronously mounted on the upper end of the vertical rotating cylinder, and a drive device capable of driving the belt timing pulley to rotate is also included.

[0016] Furthermore, it also includes automated metering and feeding units, dispersion kettles, sand mills, paint mixing and stirring kettles, filtration units, a temporary buffer tank device, intermittent vacuum centrifugal degassing system, b temporary buffer tank device, and filling units.

[0017] The discharge end of the automated metering and feeding unit is connected to the feed end of the dispersion tank. The discharge end of the dispersion tank is connected to the feed end of the sand mill. The discharge end of the sand mill is connected to the feed end of the paint mixing tank. The discharge end of the paint mixing tank is connected to the feed end of the filter unit. The discharge end of the filter unit is connected to the feed end of the temporary buffer tank device (a) and the discharge end of the temporary buffer tank device (b) is connected to the feed end of the filling unit.

[0018] Furthermore, any cycle of the intermittent vacuum centrifugal degassing system:

[0019] S1, In the initial state, the piston is in "position a", and the central channel, bypass channel and conical transition section are all filled with paint emulsion; and solenoid valves a, b and c are all in the closed state.

[0020] S2, the drive device drives the belt synchronous pulley to make the rotating drum gradually accelerate around the axis, thereby making the rotating drum, bypass pipe and centrifugal defoaming bottle synchronously accelerate around the axis of the rotating drum. At the same time, the solenoid valve a is individually controlled to enter the conduction state, and at the same time, the distance sensor monitors the position of the piston.

[0021] As the rotational speed gradually increases, the paint emulsion in the bypass channel and conical transition section will begin to push the piston downward along the axial direction under the action of the gradually increasing centrifugal force, overcoming the thrust of the thrust spring. The piston's gradual downward movement along the axial direction creates negative pressure in the defoaming chamber, which gradually increases in volume. This causes the paint emulsion in the temporary buffer tank device to gradually pass through the emulsion to be defoamed pipe, the upper fixed pipe, the central channel, and the bypass channel under the suction of the negative pressure and be introduced into the defoaming chamber, which gradually increases in volume.

[0022] When the distance sensor detects that the piston has reached the "b position", it immediately controls the a solenoid valve to switch to the closed state, so that the defoaming chamber, bypass channel and central channel connected in sequence enter the closed state;

[0023] S3, continue to gradually increase the rotation speed of the rotating cylinder. The centrifugal force on the paint emulsion in the defoaming chamber will gradually increase. When the rotation speed increases to a certain threshold, the paint emulsion in the defoaming chamber will push the piston to overcome the thrust of the thrust spring and gradually move downward under the action of the gradually increasing centrifugal force. Since the liquid volume of the paint emulsion in the defoaming chamber is constant, the further downward movement of the piston will cause the volume of the defoaming chamber to increase further, so that the upper part of the defoaming chamber will form a vacuum chamber with a gradually increasing volume. The paint emulsion in the defoaming chamber will always be in contact with the piston under the action of centrifugal force. As the piston moves further downward, the center of mass of the paint emulsion in the defoaming chamber will gradually deviate from the axis of rotation, so that the centrifugal force on the paint emulsion in the defoaming chamber will gradually increase and enter the negative pressure vacuum state.

[0024] Under the combined action of negative pressure vacuum and gradually increasing centrifugal force, the tiny air bubbles in the paint emulsion in the defoaming chamber are rapidly precipitated into the upper vacuum chamber of the defoaming chamber.

[0025] When the distance sensor detects that the piston has reached "position c", it immediately controls the rotating cylinder to stop accelerating. At this time, the piston quickly reaches "position d" with the help of the magnetic attraction of the permanent magnet column. This allows the center of mass of the paint emulsion in the defoaming chamber to deviate further from the axis of rotation without further acceleration, thereby significantly increasing the strength of the centrifugal force on the paint emulsion in the defoaming chamber and thus improving the defoaming effect. At the same time, the thrust spring enters the extreme compression state.

[0026] After the predetermined running time of S4 and "S3", the rotation speed of the rotating drum is gradually reduced, thereby gradually reducing the intensity of the centrifugal force on the paint emulsion in the defoaming chamber. When the centrifugal force of the paint emulsion in the defoaming chamber is reduced to a certain threshold, the rebound force of the thrust spring begins to exceed the resultant force of the magnetic attraction force of the permanent magnet column and the centrifugal force, thereby causing the piston to move upward along the axis under the thrust of the thrust spring. This causes the volume and vacuum degree of the upper part of the defoaming chamber to gradually decrease. When the piston moves upward to "position b" under the thrust of the thrust spring, a section of gas to be discharged is formed in the upper part, bypass channel or central channel of the defoaming chamber by the precipitation of bubbles during "S3".

[0027] S5, individually control solenoid valve b to switch to the on state, further gradually reducing the rotation speed of the rotating drum, so that the centrifugal force of the paint emulsion in the defoaming chamber is further reduced slowly. Under the thrust of the thrust spring, the piston slowly moves upward, so that the gas to be discharged formed by the bubble precipitation in the upper part of the defoaming chamber, the bypass channel and a section of the central channel is slowly discharged to the outside through solenoid valve b at the upper end of the central channel. After complete discharge, immediately control solenoid valve b to switch to the closed state.

[0028] S6, individually control solenoid valve d to switch to the conducting state, thereby reducing the rotation speed of the rotating drum to stop rotating; at this time, the centrifugal force of the defoamed paint emulsion in the defoaming chamber is completely eliminated, and the piston continues to move upward under the thrust of the thrust spring. The defoamed paint emulsion in the defoaming chamber is discharged into the temporary buffer tank device b through the bypass channel and the lower fixed pipe under the pushing of the piston.

[0029] The periodic operation from "S1" to "S6" causes the lower fixed pipe to intermittently discharge the defoamed paint emulsion into the temporary buffer tank device.

[0030] Beneficial effects: This invention combines centrifugal degassing with vacuum degassing, achieving efficient removal of microbubbles from coating emulsions. The system employs a structure where a rotating cylinder drives a centrifugal degassing bottle to rotate synchronously, utilizing the synergy of centrifugal force and negative pressure suction to actively draw in the coating emulsion.

[0031] During the defoaming stage, the piston is gradually moved downward by controlling the rotation speed, and a high vacuum area is dynamically formed in the upper part of the defoaming chamber, so that the bubbles are rapidly precipitated and broken under the combined action of vacuum and centrifugal force.

[0032] The system introduces a magnetic jump structure of permanent magnet column and magnetic block at the end of the piston stroke, which enables the piston to quickly reach the position without additional energy consumption, effectively increasing the centrifugal radius of the coating emulsion and significantly improving the equivalent centrifugal acceleration, thereby greatly enhancing the defoaming effect.

[0033] During the exhaust phase, the gas is slowly discharged by a solenoid valve at the end of the upper fixed pipe, effectively preventing the generation of secondary foam in the defoamed coating.

[0034] The discharge stage uses a piston pushing method to achieve the discharge of the defoamed coating.

[0035] Throughout the entire working cycle, the piston position is monitored in real time by a distance sensor. Combined with the closed-loop control of multiple solenoid valves and variable frequency motors, precise switching and cyclic operation of each stage of feeding, degassing, venting and discharging are achieved.

[0036] It overcomes the shortcomings of traditional single centrifugal degassing equipment, which is limited by the fixed centrifugal force due to the fixed center of gravity of the coating. It also solves the problem of low efficiency of vacuum degassing equipment due to the long-distance migration of bubbles. It is suitable for the production of high-end coatings with high viscosity, high solid content and strict requirements for bubble content. Attached Figure Description

[0037] Figure 1 This is a flowchart of the overall process flow of the coating production line;

[0038] Figure 2 This is a structural diagram of an intermittent vacuum centrifugal degassing system. Detailed Implementation

[0039] The invention will now be further described with reference to the accompanying drawings.

[0040] like Figure 1 and 2 The defoaming system of the paint production process system shown includes an automated metering and feeding unit, a dispersion kettle, a sand mill, a paint mixing and stirring kettle, a filter unit, a temporary buffer tank (a), an intermittent vacuum centrifugal defoaming system, a temporary buffer tank (b), and a filling unit. The discharge end of the automated metering and feeding unit is connected to the feed end of the dispersion kettle, the discharge end of the dispersion kettle is connected to the feed end of the sand mill, the discharge end of the sand mill is connected to the feed end of the paint mixing and stirring kettle, the discharge end of the paint mixing and stirring kettle is connected to the feed end of the filter unit, the discharge end of the filter unit is connected to the feed end of the temporary buffer tank (a), the discharge end of the temporary buffer tank (a) is connected to the feed end of the intermittent vacuum centrifugal defoaming system, the discharge end of the intermittent vacuum centrifugal defoaming system is connected to the feed end of the temporary buffer tank (b), and the discharge end of the temporary buffer tank (b) is connected to the feed end of the filling unit.

[0041] The intermittent vacuum centrifugal degassing system includes a fixed bearing support 23, within which a vertical rotating cylinder 4 is rotatably mounted via bearings. A belt synchronous pulley 3 is coaxially and synchronously mounted on the upper outer side of the vertical rotating cylinder 4. The system also includes a drive device capable of driving the belt synchronous pulley 3 to rotate. The drive device is a variable frequency speed-regulating motor, connected to the belt synchronous pulley 3 via a synchronous belt.

[0042] The rotating cylinder 4 contains a central channel 5. The intermittent vacuum centrifugal degassing system also includes an upper fixed tube 32, a lower fixed tube 20, and a centrifugal degassing bottle 17. Both the upper fixed tube 32 and the lower fixed tube 20 are fixed structures. The lower end of the upper fixed tube 32 is coaxially connected to the upper end of the central channel 5 through a rotary joint, and the upper end of the lower fixed tube 20 is coaxially connected to the lower end of the central channel 5 through a rotary joint. The rotary joint is equipped with a wear-resistant ceramic sealing ring, which can ensure that the upper fixed tube 32, the lower fixed tube 20, and the central channel 5 maintain a dynamic seal and prevent leakage when the rotating cylinder 4 rotates at high speed.

[0043] The outlet pipe 24 of the temporary buffer tank device is connected to the upper fixed pipe 32 via a bypass; the lower end of the lower fixed pipe 20 is connected to the inlet end of the temporary buffer tank device.

[0044] A bypass pipe 7 extending obliquely downwards is integrally connected to one side of the lower section of the rotating cylinder 4. The bypass pipe 7 contains a bypass channel 19, and the end of the bypass pipe 7 is coaxially and integrally connected to the centrifugal defoaming bottle 17. The angle between the bypass pipe 7 and the horizontal plane is 20° to 30°. A solenoid valve a 25 is installed in the emulsion tube 24 to be defoamed, and a solenoid valve b 2 is installed at the upper end of the upper fixed tube 32. When solenoid valve b 2 is turned on, the upper end of the upper fixed tube 32 is connected to atmospheric pressure. A solenoid valve c 6 is installed at the upper end of the lower fixed tube 20.

[0045] The upper end of the centrifugal defoaming bottle 17 is coaxially connected to the lower end of the bypass pipe 7 through the conical ring wall 8. The tail end of the centrifugal defoaming bottle 17 is integrally provided with a bottle bottom wall 13, and the bottle bottom wall 13 has a hollowed-out air pressure balance hole 14. A permanent magnet column 12 is coaxially fixedly installed on the bottle bottom wall 13. The permanent magnet column 12 is made of neodymium iron boron permanent magnet material.

[0046] A piston 10 is coaxially mounted inside the centrifugal defoaming bottle 17. A spring chamber 16 is located between the piston 10 and the bottom wall 13 of the bottle. The spring chamber 16 is connected to the outside through an air pressure balance hole 14. A thrust spring 15 is coaxially mounted inside the spring chamber 16, and the thrust spring 15 applies an axial thrust to the piston 10.

[0047] A magnetic block 11 is fixedly installed on the side of the piston 10 near the permanent magnet column 12. When the distance between the permanent magnet column 12 and the magnetic block 11 is shortened to a certain extent, a significant magnetic attraction force is formed between the permanent magnet column 12 and the magnetic block 11.

[0048] The side of piston 10 away from permanent magnet column 12 is defoaming chamber 9, and the connection between defoaming chamber 9 and bypass channel 19 is a conical transition section 9a.

[0049] The centrifugal defoaming bottle 17 includes "position a", "position b", "position c" and "position d" from top to bottom along the axial direction.

[0050] When the rotating cylinder 4 is stationary and the defoaming chamber 9 is under atmospheric pressure, the thrust spring 15 pushes the piston 10 upward to "position a" and is limited by the conical ring wall 8.

[0051] "Position b" is located in the middle section of centrifugal defoaming bottle 17.

[0052] When the piston 10 is in the "c position", a significant magnetic attraction is formed between the permanent magnet column 12 and the magnetic block 11;

[0053] When the piston 10 is in the "d position", the permanent magnet column 12 just makes contact with the magnetic block 11.

[0054] A distance sensor 35 is installed on the inner side of the bottle bottom wall 13. The distance sensor 35 can monitor the distance between the bottle bottom wall 13 and the piston 10, thereby realizing the real-time position of the piston 10. The distance sensor 35 adopts a non-contact laser displacement sensor, which can provide real-time and accurate feedback of the position signal of the piston 10 to the control system, providing a closed-loop control basis for the coordinated operation of various solenoid valves and drive devices.

[0055] Any cycle of the intermittent vacuum centrifugal degassing system:

[0056] S1, in the initial state, the piston 10 is in the "a position", and the central channel 5, the bypass channel 19 and the conical transition section 9a are all filled with paint emulsion; and the a solenoid valve 25, the b solenoid valve 2 and the c solenoid valve 6 are all in the closed state.

[0057] S2, the drive device drives the belt synchronous pulley 3 to make the rotating drum 4 gradually accelerate around the axis, thereby making the rotating drum 4, bypass pipe 7, and centrifugal defoaming bottle 17 synchronously accelerate around the axis of the rotating drum 4. At the same time, the solenoid valve 25 is individually controlled to enter the conduction state, and at the same time, the distance sensor 35 monitors the position of the piston 10.

[0058] As the rotational speed gradually increases, the paint emulsion in the bypass channel 19 and the conical transition section 9a will, under the action of the gradually increasing centrifugal force, begin to push the piston 10 to overcome the thrust of the thrust spring 15 and gradually move downward along the axial direction. The piston 10 gradually moves downward along the axial direction, causing the defoaming chamber 9, which gradually increases in volume, to generate negative pressure. This allows the paint emulsion in the temporary buffer tank device to gradually pass through the emulsion to be defoamed pipe 24, the upper fixed pipe 32, the central channel 5, and the bypass channel 19 under the suction of negative pressure and be introduced into the defoaming chamber 9, which gradually increases in volume. This process utilizes the synergistic effect of centrifugal force and negative pressure suction to achieve active quantitative intake of paint emulsion.

[0059] When the distance sensor 35 detects that the piston 10 has reached the "b position", it immediately controls the solenoid valve 25 to switch to the closed state, so that the defoaming chamber 9, the bypass channel 19 and the central channel 5 connected in sequence enter the closed state; at this time, the defoaming chamber 9 has sucked in a preset volume of paint emulsion, which is determined by the stroke volume of the piston 10 from the "a position" to the "b position". By controlling the acceleration curve of the rotating cylinder 4, the feeding rate and feeding amount can be precisely adjusted.

[0060] S3, continue to gradually increase the rotation speed of the rotating cylinder 4. The centrifugal force on the paint emulsion in the defoaming chamber 9 will gradually increase further. When the rotation speed increases to a certain threshold, the paint emulsion in the defoaming chamber 9 will push the piston 10 to gradually move downward under the action of the gradually increasing centrifugal force, thus overcoming the thrust of the thrust spring 15. Since the liquid volume of the paint emulsion in the defoaming chamber 9 is constant, the further downward movement of the piston 10 will cause the volume of the defoaming chamber 9 to further increase, thereby forming a vacuum chamber with a gradually increasing volume in the upper part of the defoaming chamber 9. The absolute pressure of the vacuum chamber can be reduced to 0.02-0.05MPa, forming a high vacuum environment.

[0061] Under the action of centrifugal force, the paint emulsion in the defoaming chamber 9 always adheres to the piston 10. As the piston 10 moves further downward, the center of mass of the paint emulsion in the defoaming chamber 9 gradually deviates from the axis of rotation. As a result, the centrifugal force on the paint emulsion in the defoaming chamber 9 gradually increases, and it enters a negative pressure vacuum state. The vacuum environment greatly reduces the gas-liquid interfacial tension on the surface of the bubbles, which significantly reduces the stability of the bubble wall. At the same time, the pressure difference between the inside and outside of the bubbles increases, which accelerates the bubble breakage. The intensity of centrifugal force causes the bubbles to move faster in the opposite direction of centrifugal force, thereby accelerating precipitation. The combined effect of centrifugal force and negative pressure effectively improves the bubble precipitation efficiency.

[0062] The tiny air bubbles in the paint emulsion inside the defoaming chamber 9 are rapidly released into the upper vacuum chamber inside the defoaming chamber 9 under the combined action of negative pressure vacuum and gradually increasing centrifugal force.

[0063] When the distance sensor 35 detects that the piston 10 has reached the "c position", it immediately controls the rotating cylinder 4 to stop accelerating. At this time, the piston 10 quickly reaches the "d position" with the help of the magnetic attraction of the permanent magnet column 12. This allows the center of mass of the paint emulsion in the defoaming chamber 9 to deviate further from the axis of rotation without further acceleration. This significantly increases the intensity of the centrifugal force on the paint emulsion in the defoaming chamber 9, thereby improving the defoaming effect. By utilizing the magnetic jump characteristic, the effective centrifugal radius is increased instantaneously without additional energy consumption, and the equivalent centrifugal acceleration is further increased from the gravitational acceleration multiple g value at the original rotation speed, thus strengthening the defoaming effect. At the same time, the thrust spring 15 enters the extreme compression state.

[0064] After the predetermined running time of S4 and S3, the rotation speed of the rotating cylinder 4 is gradually reduced, thereby gradually reducing the intensity of the centrifugal force on the paint emulsion in the defoaming chamber 9. When the centrifugal force of the paint emulsion in the defoaming chamber 9 decreases to a certain threshold, the rebound force of the thrust spring 15 begins to exceed the resultant force of the magnetic attraction force of the permanent magnet column 12 and the centrifugal force, causing the piston 10 to move upward along the axis under the thrust of the thrust spring 15. This causes the volume and vacuum degree of the upper part of the defoaming chamber 9 to gradually decrease. When the piston 10 moves upward to the "b position" under the thrust of the thrust spring 15, a section of gas to be discharged is formed in the upper part of the defoaming chamber 9, the bypass channel 19, or the central channel 5, which is formed by the precipitation of bubbles during the "S3" process. This gas to be discharged mainly consists of air precipitated from the paint emulsion, a small amount of solvent vapor, and gas released by the collapse of microbubbles, with a total volume of less than 5% of the volume of the defoaming chamber 9.

[0065] S5, individually control solenoid valve 2 to switch to the conducting state, further gradually reducing the rotation speed of the rotating drum 4, so that the centrifugal force of the paint emulsion in the defoaming chamber 9 is further reduced slowly. The piston 10 slowly moves upward under the thrust of the thrust spring 15, so that the gas to be discharged formed by the bubble precipitation in the upper part of the defoaming chamber 9, the bypass channel 19 and a section of the central channel 5, is slowly discharged to the outside through solenoid valve 2 at the upper end of the central channel 5. After complete discharge, immediately control solenoid valve 2 to switch to the closed state. This exhaust process adopts a slow pressure reduction method to prevent the defoamed paint emulsion from generating secondary foam due to excessive exhaust. The exhaust speed is precisely controlled by the deceleration curve of the rotating drum 4, and the exhaust time is generally 5-15 seconds.

[0066] S6, individually control solenoid valve 6 to switch to the conducting state, thereby reducing the rotation speed of rotating drum 4 to stop rotating; at this time, the centrifugal force of the defoamed paint emulsion in defoaming chamber 9 completely disappears, and piston 10 continues to move upward under the thrust of thrust spring 15. Under the pushing of piston 10, the defoamed paint emulsion in defoaming chamber 9 is discharged into temporary buffer tank device b through bypass channel 19 and lower fixed pipe 20 in sequence.

[0067] The periodic operation from "S1" to "S6" causes the lower fixed pipe 20 to intermittently discharge the defoamed paint emulsion into the temporary buffer tank device.

[0068] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A defoaming system for a coating production process, characterized in that: It includes a temporary buffer tank device (a), an intermittent vacuum centrifugal degassing system, and a temporary buffer tank device (b). The discharge end of the temporary buffer tank device (a) is connected to the feed end of the intermittent vacuum centrifugal degassing system, and the discharge end of the intermittent vacuum centrifugal degassing system is connected to the feed end of the temporary buffer tank device (b). The intermittent vacuum centrifugal degassing system includes a rotating cylinder (4) with a central channel (5) inside; it also includes an upper fixed pipe (32), a lower fixed pipe (20), and a centrifugal degassing bottle (17); the lower end of the upper fixed pipe (32) is coaxially connected to the upper end of the central channel (5) through a rotary joint, and the upper end of the lower fixed pipe (20) is coaxially connected to the lower end of the central channel (5) through a rotary joint; the emulsion pipe (24) to be degassed at the discharge end of the a temporary buffer tank device is bypassed and connected to the upper fixed pipe (32); the lower end of the lower fixed pipe (20) is connected to the feed end of the b temporary buffer tank device; The lower section of the rotating cylinder (4) is integrally connected to a bypass pipe (7) extending obliquely downward. The bypass pipe (7) contains a bypass channel (19), and the end of the bypass pipe (7) is coaxially connected to the centrifugal defoaming bottle (17). The emulsion tube (24) to be defoamed is equipped with a solenoid valve (25), and the upper end of the upper fixed tube (32) is equipped with a solenoid valve (2). When the solenoid valve (2) is turned on, the upper end of the upper fixed tube (32) is connected to atmospheric pressure; the upper end of the lower fixed tube (20) is equipped with a solenoid valve (6).

2. The defoaming system of the coating production process system according to claim 1, characterized in that: The upper end of the centrifugal defoaming bottle (17) is coaxially connected to the lower end of the bypass pipe (7) through the conical ring wall (8), and the tail end of the centrifugal defoaming bottle (17) is integrally provided with a bottle bottom wall (13); a permanent magnet column (12) is coaxially fixedly installed on the bottle bottom wall (13). A piston (10) is coaxially and movably disposed inside the centrifugal defoaming bottle (17), and a spring chamber (16) is located between the piston (10) and the bottom wall (13) of the bottle; a thrust spring (15) is coaxially disposed inside the spring chamber (16), and the thrust spring (15) applies an axial thrust to the piston (10); A magnetic block (11) is fixedly provided on the side of the piston (10) near the permanent magnet column (12). When the distance between the permanent magnet column (12) and the magnetic block (11) is shortened to a certain extent, a significant magnetic attraction force is formed between the permanent magnet column (12) and the magnetic block (11). The side of the piston (10) away from the permanent magnet column (12) is the defoaming chamber (9), and the connection between the defoaming chamber (9) and the bypass channel (19) is a conical transition section (9a).

3. The defoaming system of the coating production process system according to claim 2, characterized in that: The bottom wall (13) of the bottle has a hollowed-out air pressure balance hole (14); the spring chamber (16) is connected to the outside through the air pressure balance hole (14).

4. The defoaming system of the coating production process system according to claim 3, characterized in that: The centrifugal defoaming bottle (17) includes "position a", "position b", "position c" and "position d" from top to bottom along the axial direction; When the rotating cylinder (4) is stationary and the defoaming chamber (9) is under atmospheric pressure, the thrust spring (15) pushes the piston (10) upward to "position a" and is limited by the conical ring wall (8); "Position b" is located in the middle section of the centrifugal defoaming bottle (17); When the piston (10) is in the "c position", a significant magnetic attraction is formed between the permanent magnet column (12) and the magnetic block (11); When the piston (10) is in the "d position", the permanent magnet column (12) just makes contact with the magnetic block (11).

5. The defoaming system of the coating production process system according to claim 4, characterized in that: A distance sensor (35) is installed on the inner side of the bottom wall (13) of the bottle. The distance sensor (35) can monitor the distance between the bottom wall (13) of the bottle and the piston (10), thereby enabling the real-time knowledge of the location of the piston (10).

6. The defoaming system of the coating production process system according to claim 5, characterized in that: It also includes a fixed bearing support (23), in which a vertical rotating cylinder (4) is rotatably mounted via a bearing; a belt synchronous pulley (3) is coaxially mounted on the upper end of the vertical rotating cylinder (4), and it also includes a drive device that can drive the belt synchronous pulley (3) to rotate.

7. The defoaming system of the coating production process system according to claim 1, characterized in that: It also includes automated metering and feeding units, dispersion kettles, sand mills, paint mixing and stirring kettles, filter units, a. temporary buffer tank devices, intermittent vacuum centrifugal degassing systems, b. temporary buffer tank devices, and filling units; The discharge end of the automated metering and feeding unit is connected to the inlet end of the dispersion tank. The discharge end of the dispersion tank is connected to the inlet end of the sand mill. The discharge end of the sand mill is connected to the inlet end of the paint mixing tank. The discharge end of the paint mixing tank is connected to the inlet end of the filter unit. The discharge end of the filter unit is connected to the inlet end of the temporary buffer tank device (a). The discharge end of the temporary buffer tank device (b) is connected to the inlet end of the filling unit.

8. The defoaming process of the defoaming system in the coating production process system according to claim 6, characterized in that: Any cycle of the intermittent vacuum centrifugal degassing system: S1, In the initial state, the piston (10) is in the "a position", and the central channel (5), bypass channel (19) and conical transition section (9a) are filled with paint emulsion; and the a solenoid valve (25), b solenoid valve (2) and c solenoid valve (6) are all in the closed state; S2, the drive device drives the belt synchronous pulley (3) to make the rotating drum (4) gradually accelerate around the axis, thereby making the rotating drum (4), bypass pipe (7), and centrifugal defoaming bottle (17) gradually accelerate around the axis of the rotating drum (4) simultaneously. At the same time, the solenoid valve (25) is individually controlled to enter the conduction state. Meanwhile, the distance sensor (35) monitors the position of the piston (10). As the rotation speed gradually increases, the paint emulsion in the bypass channel (19) and the conical transition section (9a) will begin to push the piston (10) against the thrust of the thrust spring (15) under the action of the gradually increasing centrifugal force. The piston (10) gradually moves downward along the axial direction, causing the defoaming chamber (9) to generate negative pressure, so that the paint emulsion in the temporary buffer tank device is gradually introduced into the defoaming chamber (9) with the gradually increasing volume under the suction of negative pressure through the emulsion pipe (24), the upper fixed pipe (32), the central channel (5) and the bypass channel (19); When the distance sensor (35) detects that the piston (10) has reached the "b position", it immediately controls the a solenoid valve (25) to switch to the closed state, so that the defoaming chamber (9), bypass channel (19) and central channel (5) connected in sequence enter the closed state; S3, continue to gradually increase the rotation speed of the rotating cylinder (4), the centrifugal force on the paint emulsion in the defoaming chamber (9) further gradually increases, when the rotation speed increases to a certain threshold, the paint emulsion in the defoaming chamber (9) pushes the piston (10) to further overcome the thrust of the thrust spring (15) and gradually move downward under the action of the gradually increasing centrifugal force. Since the liquid volume of the paint emulsion in the defoaming chamber (9) is constant, the further downward movement of the piston (10) leads to the further increase of the volume of the defoaming chamber (9), so that the upper part of the defoaming chamber (9) forms a vacuum chamber with a gradually increasing volume. The paint emulsion in the defoaming chamber (9) always sticks to the piston (10) under the action of centrifugal force. As the piston (10) moves further downward, the center of mass of the paint emulsion in the defoaming chamber (9) gradually deviates from the rotation axis, so that the centrifugal force on the paint emulsion in the defoaming chamber (9) gradually increases and enters the negative pressure vacuum state. The tiny bubbles in the paint emulsion in the defoaming chamber (9) are rapidly precipitated into the upper vacuum chamber of the defoaming chamber (9) under the combined action of negative pressure vacuum and gradually increasing centrifugal force. When the distance sensor (35) detects that the piston (10) has reached the "c position", it immediately controls the rotating cylinder (4) to stop accelerating. At this time, the piston (10) quickly reaches the "d position" with the help of the magnetic attraction of the permanent magnet column (12), so that the center of mass of the paint emulsion in the defoaming chamber (9) is further deviated from the axis of rotation without further acceleration, thereby significantly improving the strength of the paint emulsion in the defoaming chamber (9) under the centrifugal force, thereby improving the defoaming effect. At the same time, the thrust spring (15) enters the extreme compression state. After the predetermined time of S4 and "S3", the rotation speed of the rotating cylinder (4) is gradually reduced, thereby gradually reducing the intensity of the centrifugal force on the paint emulsion in the defoaming chamber (9). When the centrifugal force of the paint emulsion in the defoaming chamber (9) is reduced to a certain threshold, the rebound force of the thrust spring (15) begins to be greater than the resultant force of the magnetic attraction force of the permanent magnet column (12) and the centrifugal force, thereby causing the piston (10) to move upward along the axis under the thrust of the thrust spring (15), thereby gradually reducing the volume and vacuum degree of the upper part of the defoaming chamber (9). When the piston (10) moves upward to the "b position" under the thrust of the thrust spring (15), a section of gas to be discharged is formed in the upper part, bypass channel (19) or central channel (5) of the defoaming chamber (9) by the precipitation of bubbles during the "S3" process. S5, control the solenoid valve (2) to switch to the conducting state, further gradually reduce the speed of the rotating drum (4), so that the centrifugal force of the paint emulsion in the defoaming chamber (9) is further reduced slowly. The piston (10) slowly moves upward under the thrust of the thrust spring (15), so that the gas to be discharged formed by the bubble precipitation in the upper part of the defoaming chamber (9), the bypass channel (19) and the central channel (5) is slowly discharged to the outside through the solenoid valve (2) at the upper end of the central channel (5). After it is completely discharged, control the solenoid valve (2) to switch to the closed state immediately. S6, individually control solenoid valve (6) to switch to the conducting state, thereby reducing the rotation speed of the rotating drum (4) to stop rotating; at this time, the centrifugal force of the defoamed paint emulsion in the defoaming chamber (9) completely disappears, and the piston (10) continues to move upward under the thrust of the thrust spring (15). The defoamed paint emulsion in the defoaming chamber (9) is discharged into the temporary buffer tank device (b) through the bypass channel (19) and the lower fixed pipe (20) in sequence under the pushing of the piston (10). The periodic operation from "S1" to "S6" causes the lower fixed pipe (20) to intermittently discharge the defoamed paint emulsion into the temporary buffer tank device.

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