Variable-volume supercritical carbon dioxide spraying device and method
By adopting variable volume control technology in supercritical carbon dioxide spraying devices, the problem of insufficient response of the equipment and large accuracy errors is solved, and the precise regulation and stable mixing of supercritical carbon dioxide and coatings is achieved, which promotes supercritical carbon dioxide spraying technology application.
Patent Information
- Application Number
- CN202411362044.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-27
- Publication Date
- 2024-12-27
AI Technical Summary
The existing supercritical carbon dioxide spraying devices have phase transition problems caused by insufficient equipment response, large accuracy error and instantaneous pressure changes in spraying, which affects the viscosity, solubility and permeability of the coating and limits its application promotion.
Using variable volume supercritical carbon dioxide spraying device, the precise regulation of supercritical carbon dioxide and coatings is achieved through variable volume supercritical carbon dioxide units and coating units, combined with capillary mixing units and selection control units, ensuring a stable temperature during the spraying process. and pressure.
It realizes precise regulation of supercritical carbon dioxide and coatings in temperature, pressure and flow, and mixes them stably, reduces operating energy consumption and equipment investment, which helps the promotion and application of supercritical carbon dioxide spraying technology.
Smart Images
Figure CN119186871A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a carbon dioxide spraying device, and in particular to a variable volume supercritical carbon dioxide spraying device and method. Background Art
[0002] In recent years, under the influence and promotion of various environmental protection policies, water-based coatings have been vigorously developed and promoted, but solvent-based coatings still account for about 70% of the coating market due to their excellent weather resistance and coating effects. The fast-evaporating solvents are the main source of VOCs pollution, so it is extremely important to find a method that can replace solvents and reduce VOCs. Carbon dioxide can reach a supercritical state under the conditions of a temperature of 31.26℃ and a pressure of 7.38Mpa. Its characteristics are high density, strong permeability, excellent solubility and low viscosity in resins in the supercritical state, making it a very potential technology to replace organic solvents in coatings.
[0003] However, when using supercritical carbon dioxide as a solvent, there are the following problems:
[0004] 1. Controlling the pressure and flow of supercritical carbon dioxide requires high-precision sensors, booster pumps and flow pumps, which are expensive and pose challenges to application promotion and subsequent maintenance;
[0005] 2. In order to control the flow rate, carbon dioxide is usually pressurized and cooled to become liquid before being transported through a metering pump. When mixed with the paint, it needs to be heated to above 32°C to form a supercritical state, which increases the operating energy consumption;
[0006] 3. During the spraying process, when the trigger is pulled, the pressure in the pipeline is released quickly, causing the supercritical carbon dioxide to change phase instantly due to the pressure change, affecting its viscosity, solubility and permeability to the coating, thereby deteriorating the spraying effect. These problems have not been effectively solved, resulting in certain restrictions on the application of supercritical carbon dioxide as a solvent in spraying, which is not conducive to the promotion of this technology.
[0007] As the prior art, CN118287279A discloses a supercritical carbon dioxide spraying device, which mainly uses a carbon dioxide compression pump, a carbon dioxide flowmeter, a condenser, a heater, etc., and the equipment operation and equipment costs are high. Patent CN117358539A discloses a supercritical carbon dioxide spraying method controlled by viscosity, which mainly calculates the specific target values of the temperature, pressure and component ratio of the supercritical carbon dioxide and the coating under the set target viscosity value through the viscosity calculation model in the viscosity control module; then the system is controlled in real time according to the target value, so as to spray after reaching the viscosity target value. In the actual application process, the method still needs a high-precision and high-responsive carbon dioxide booster pump and a carbon dioxide flowmeter, but even with a high-precision booster pump and a flowmeter, the control accuracy has an error range of 1-3%, and the maximum error value of the two can reach 6%, so it is still difficult to control the blending viscosity in actual application.
[0008] As the second prior art, CN108855663A discloses a paint spraying system and method using ionic liquid mixed with high-pressure carbon dioxide as a mixed solvent. This method introduces a more expensive ionic liquid for mixing. Although it can increase the dissolution of carbon dioxide, the addition of the ionic liquid changes the original paint formula. Therefore, the impact on the function and application of the paint still needs to be investigated. Summary of the invention
[0009] The present invention aims to solve the problems in the prior art of insufficient response of the equipment itself, large precision error and unstable supercritical carbon dioxide phase change and filling amount caused by pressure changes during spraying, and proposes a variable volume supercritical carbon dioxide spraying device and method.
[0010] In order to solve the above technical problems, the present invention is solved by the following technical solutions:
[0011] A variable volume supercritical carbon dioxide spraying device comprises a spray gun, a variable volume supercritical carbon dioxide unit, a variable volume coating unit, and a capillary mixing unit; the variable volume supercritical carbon dioxide unit is used to provide supercritical carbon dioxide to the capillary mixing unit, the variable volume coating unit is used to provide coating to the capillary mixing unit, the capillary mixing unit is used to mix the received coating and supercritical carbon dioxide, and spray the mixed coating through the spray gun.
[0012] Preferably, a supercritical carbon dioxide selection unit is further included, through which supercritical carbon dioxide with different flow rates is selected to be supplied to the capillary mixing unit.
[0013] Preferably, the variable volume supercritical carbon dioxide unit includes a carbon dioxide cylinder, a carbon dioxide temperature regulating unit, a variable volume carbon dioxide chamber and a carbon dioxide control unit; the carbon dioxide cylinder provides carbon dioxide to the variable volume carbon dioxide chamber via a first solenoid valve, the carbon dioxide temperature regulating unit is used to adjust the temperature of the variable volume carbon dioxide chamber, and the carbon dioxide control unit is used to control the pressure of the variable volume carbon dioxide chamber.
[0014] Preferably, the variable volume paint unit includes a paint tank, a paint temperature adjustment unit, a variable volume paint cavity and a paint control unit; the paint tank provides paint to the variable volume paint cavity via a second solenoid valve, the paint temperature adjustment unit is used to adjust the temperature of the variable volume paint cavity, and the paint control unit is used to control the pressure of the variable volume paint.
[0015] Preferably, the supercritical carbon dioxide selection unit includes a selection control unit, an array of solenoid valves and an array of capillaries, and the number of solenoid valves corresponds to the number of capillaries. The selection control unit controls the conduction and closing of the solenoid valves to control the supercritical carbon dioxide to flow into the capillary mixing unit through different capillaries, thereby achieving the purpose of controlling the flow rate.
[0016] Preferably, the carbon dioxide control unit includes a carbon dioxide main control module, a carbon dioxide screw gear module, a carbon dioxide servo motor and a carbon dioxide piston; the carbon dioxide main control module is used to control the carbon dioxide servo motor, the carbon dioxide servo motor drives the carbon dioxide screw gear module, and the carbon dioxide screw gear module controls the movement of the carbon dioxide piston, thereby adjusting the volume of the variable volume carbon dioxide chamber to achieve the purpose of regulating pressure.
[0017] Preferably, the paint control unit includes a paint main control module, a paint screw gear module, a paint servo motor and a paint piston; the paint main control module is used to control the paint servo motor, the paint servo motor drives the paint screw gear module, and the paint screw gear module controls the movement of the paint piston, thereby adjusting the volume of the variable volume paint cavity.
[0018] In order to solve the above technical problems, the present invention is characterized in that the variable volume supercritical carbon dioxide spraying device is realized by a variable volume supercritical carbon dioxide spraying method.
[0019] Preferably, the pressure and temperature of the supercritical carbon dioxide and the coating are adjusted; the pressure and flow rate of the supercritical carbon dioxide are adjusted by a variable volume supercritical carbon dioxide unit, and the pressure and flow rate of the coating are adjusted by a variable volume coating unit;
[0020] The supercritical carbon dioxide and the coating are mixed by selecting the flow rate of the supercritical carbon dioxide through the supercritical carbon dioxide selection unit according to the different flow rates of the nozzles and entering the capillary mixing unit for mixing the supercritical carbon dioxide and the coating.
[0021] The present invention has significant technical effects due to the adoption of the above technical solution:
[0022] The present invention can realize precise regulation of the temperature, pressure and flow of supercritical carbon dioxide and coating in the process of using a carbon dioxide booster pump and a flow meter, in the case where the equipment itself does not respond fast enough, the accuracy error is large, and the instantaneous pressure change during spraying causes the supercritical carbon dioxide phase change and the filling amount to be unstable. Therefore, the supercritical carbon dioxide can control the solubility and viscosity of the coating, thereby achieving the purpose of stable mixing.
[0023] The method adopted by the invention reduces operating energy consumption and equipment investment, and is helpful for the promotion and application of supercritical carbon dioxide spraying. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 Schematic diagram of the device of the present invention;
[0025] Figure 2 Schematic diagram of a variable volume supercritical carbon dioxide unit of the present invention;
[0026] Figure 3 Schematic diagram of a variable volume coating unit of the present invention.
[0027] Among them, 1—spray gun, 2—variable volume supercritical carbon dioxide unit, 3—variable volume paint unit, 4—capillary mixing unit, 5—supercritical carbon dioxide selection unit, 21—carbon dioxide cylinder, 22—carbon dioxide temperature adjustment unit, 23—variable volume carbon dioxide chamber, 24—carbon dioxide control unit, 25—first solenoid valve, 31—paint tank, 32—paint temperature adjustment unit, 33—variable volume paint chamber, 34—paint control unit, 35—second solenoid valve, 51—selection control unit, 52—array solenoid valve, 53—array capillary, 241—carbon dioxide main control module, 242—carbon dioxide screw gear module, 243—carbon dioxide servo motor, 244—carbon dioxide piston, 341—paint main control module, 342—paint screw gear module, 343—paint servo motor, 344—paint piston. DETAILED DESCRIPTION
[0028] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.
[0029] Example 1
[0030] A variable volume supercritical carbon dioxide spraying device comprises a spray gun 1, which also comprises a variable volume supercritical carbon dioxide unit 2, a variable volume coating unit 3, and a capillary mixing unit 4; the variable volume supercritical carbon dioxide unit 2 is used to provide supercritical carbon dioxide to the capillary mixing unit 4, the variable volume coating unit 3 is used to provide coating to the capillary mixing unit 4, the capillary mixing unit 4 is used to mix the received coating and supercritical carbon dioxide, and spray the mixed coating through the spray gun 1.
[0031] The variable volume supercritical carbon dioxide unit 2 includes a carbon dioxide cylinder 21, a carbon dioxide temperature regulating unit 22, a variable volume carbon dioxide chamber 23 and a carbon dioxide control unit 24; the carbon dioxide cylinder 21 provides carbon dioxide to the variable volume carbon dioxide chamber 23 via a first solenoid valve 25, the carbon dioxide temperature regulating unit 22 is used to adjust the temperature of the variable volume carbon dioxide chamber 23, and the carbon dioxide control unit 24 is used to control the pressure of the variable volume carbon dioxide chamber 23.
[0032] The variable volume paint unit 3 includes a paint tank 31, a paint temperature adjustment unit 32, a variable volume paint cavity 33 and a paint control unit 34; the paint tank 31 provides paint to the variable volume paint cavity 33 via a second solenoid valve 35, the paint temperature adjustment unit 32 is used to adjust the temperature of the variable volume paint cavity 33, and the paint control unit 34 is used to control the pressure of the variable volume paint.
[0033] The carbon dioxide control unit 24 includes a carbon dioxide main control module 241, a carbon dioxide screw gear module 242, a carbon dioxide servo motor 243 and a carbon dioxide piston 244; the carbon dioxide main control module 241 is used to control the carbon dioxide servo motor 243, the carbon dioxide servo motor 243 drives the carbon dioxide screw gear module 242, and the carbon dioxide screw gear module 242 controls the movement of the carbon dioxide piston 244, thereby adjusting the volume of the variable volume carbon dioxide chamber 23 to achieve the purpose of regulating pressure.
[0034] The paint control unit 34 includes a paint main control module 341, a paint screw gear module 342, a paint servo motor 343 and a paint piston 344; the paint main control module 341 is used to control the paint servo motor 343, the paint servo motor 343 drives the paint screw gear module 342, and the paint screw gear module 342 controls the movement of the paint piston 344, thereby adjusting the volume of the variable volume paint cavity 33 to achieve the purpose of regulating pressure.
[0035] Example 2
[0036] Based on Example 1, this example further includes a supercritical carbon dioxide selection unit 5 , through which supercritical carbon dioxide with different flow rates is selected to flow to the capillary mixing unit 4 .
[0037] The supercritical carbon dioxide selection unit 5 includes a selection control unit 51, an array of solenoid valves 52 and an array of capillaries 53, and the number of the solenoid valves corresponds to the number of the capillaries. The selection control unit 51 controls the conduction and closing of the solenoid valves to control the supercritical carbon dioxide to flow into the capillary mixing unit 4 through different capillaries, thereby achieving the purpose of controlling the flow rate.
[0038] The bottom outlet of the variable volume coating unit is connected to the inlet 301 of the capillary mixing unit 4, Figure 1 In the embodiment, the supercritical carbon dioxide selection unit 5 includes three capillaries, namely capillary 1, capillary 2 and capillary 3, which are connected to the capillary mixing unit 4, and the outlet of the capillary mixing unit 4 is connected to the spray gun.
[0039] Example 3
[0040] Based on the above embodiments, this embodiment is a variable volume supercritical carbon dioxide spraying method, which realizes a variable volume supercritical carbon dioxide spraying device through a variable volume supercritical carbon dioxide spraying method.
[0041] Regulating the pressure and temperature of supercritical carbon dioxide and coating; regulating the pressure and flow rate of supercritical carbon dioxide through variable volume supercritical carbon dioxide unit 2, and regulating the pressure and flow rate of coating through variable volume coating unit 3;
[0042] The supercritical carbon dioxide and the coating are mixed by selecting the flow rate of the supercritical carbon dioxide through the supercritical carbon dioxide selection unit 5 according to the different flow rates of the nozzles and entering the capillary mixing unit 4 for mixing the supercritical carbon dioxide and the coating.
[0043] When the supercritical carbon dioxide and paint reach the set value, the spray gun selects a nozzle diameter of 0.27mm and a flow rate of 0.4L / min, and the carbon dioxide selection control unit opens the third solenoid valve to provide stable supercritical carbon dioxide through capillary 1. At this time, the flow ratio of supercritical carbon dioxide 113 and paint is 1:10. When the trigger is pulled to spray through the spray gun, the system pressure drops, and the pressure and temperature probes and the measured data are transmitted to the carbon dioxide main control module and the paint main control module. When the carbon dioxide main control module and the paint main control module do not match the measured data with the preset data, the carbon dioxide servo motor 243 and the paint servo motor 343 are started, and the carbon dioxide piston and the paint piston are lowered to reduce the space of the variable volume carbon dioxide cavity and the paint cavity, thereby providing the pressure required for continuous spraying.
[0044] When the spray piece becomes larger and requires high-flow spraying, the spray gun selects a nozzle diameter of 0.48mm and a flow rate of 1.29L / min. The carbon dioxide main control module closes the fourth solenoid valve, opens the fourth solenoid valve, and provides stable supercritical carbon dioxide through capillary 2. At this time, the flow ratio of supercritical carbon dioxide and paint is 1:10. When the trigger is pulled to spray through the spray gun, the system pressure drops, and the data measured by the pressure and temperature probe is transmitted to the carbon dioxide main control module and the paint main control module. When the carbon dioxide main control module and the paint main control module do not match the measured data and the preset data, the carbon dioxide servo motor 243 and the paint servo motor 343 are started, and the carbon dioxide piston and the paint piston are lowered to reduce the space of the variable volume carbon dioxide cavity 23 and the paint cavity 33, providing the pressure required for continuous spraying.
[0045] When the spray piece becomes larger and requires a larger flow rate for spraying, the spray gun selects a nozzle diameter of 1mm and a flow rate of 3L / min. The carbon dioxide selection control unit closes the fifth solenoid valve, opens the fifth solenoid valve, and provides stable supercritical carbon dioxide through capillary 2. At this time, the flow ratio of supercritical carbon dioxide to paint is 1:10. When the trigger is pulled to spray through the spray gun, the system pressure drops, and the data measured by the pressure and temperature probe is transmitted to the carbon dioxide main control module and the paint main control module. When the carbon dioxide main control module and the paint main control module do not match the measured data and the preset data, the carbon dioxide servo motor 243 and the paint servo motor 343 are started, and the carbon dioxide piston and the paint piston are lowered to reduce the space of the variable volume carbon dioxide cavity 23 and the paint cavity 33, providing the pressure required for continuous spraying.
[0046] When the screw rod descends to 10 cm from the bottom, the third electromagnetic valve, the fourth electromagnetic valve and the fifth electromagnetic valve are closed. The carbon dioxide piston and the paint piston are first raised by the carbon dioxide servo motor 243 and the paint servo motor 343, and then the first electromagnetic valve and the second electromagnetic valve are opened to replenish carbon dioxide and paint. Then the previous steps are repeated.
[0047] The temperature is set between 37-45°C and the pressure is set between 7.6-20 MPa through the carbon dioxide main control module. In order to achieve the set pressure, the carbon dioxide servo motor 243 drives the carbon dioxide screw gearbox and controls the up and down movement of the carbon dioxide piston through the screw connected to it to achieve carbon dioxide injection and pressurization.
[0048] When the set value is activated, the carbon dioxide selection control unit first closes the third solenoid valve, the fourth solenoid valve and the fifth solenoid valve. When the piston is lifted to two-thirds of the variable volume carbon dioxide chamber 23, the first solenoid valve is closed after a sufficient amount of carbon dioxide is inhaled from the carbon dioxide cylinder. The temperature and pressure probe 104 transmits the measured temperature and pressure values to the carbon dioxide selection control unit. When the set pressure is not reached, the carbon dioxide servo motor 243 is started to push the piston downward to apply pressure to the carbon dioxide until the set value is reached. When the set temperature is not reached, the carbon dioxide temperature adjustment unit is turned on to heat the variable volume carbon dioxide chamber 33. Since heating will cause a change in the pressure value, the carbon dioxide control module is used to adjust the up and down movement of the piston to change the volume to reach the supercritical carbon dioxide at the set temperature and pressure.
[0049] First, the temperature is set between 37-45°C and the pressure is set between 7.6-20 MPa through the paint main control module. The pressure of the paint is lower than the pressure of supercritical carbon dioxide, and the pressure difference is 0.05-5 MPa. In order to reach the set pressure, the paint servo motor drives the paint screw gearbox and controls the up and down movement of the paint piston through the screw connected to it to achieve the pressurization of the paint. When the set value is started, the second solenoid valve is opened, and the paint piston is lifted to two-thirds of the variable volume paint cavity, the second solenoid valve is closed after a sufficient amount of paint is sucked from the paint tank. The temperature and pressure probe transmits the measured temperature and pressure values to the paint main control module. When the set pressure is not reached, the paint servo motor is started to push the piston downward to apply pressure to the paint until the set value is reached. When the set temperature is not reached, the paint temperature adjustment unit is turned on to heat the variable volume paint cavity 33. Since heating will cause a change in the pressure value, the paint main control module is used to adjust the up and down movement of the piston to change the volume to reach the set temperature and pressure paint. Specific application project name: Key technology and application demonstration of supercritical carbon dioxide green spraying; Project number: 2019YFE0122100.
Claims
1. A variable volume supercritical carbon dioxide spraying device, comprising a spray gun (1), characterized in that: It also comprises a variable volume supercritical carbon dioxide unit (2), a variable volume coating unit (3), and a capillary mixing unit (4); the variable volume supercritical carbon dioxide unit (2) is used to provide supercritical carbon dioxide to the capillary mixing unit (4), the variable volume coating unit (3) is used to provide coating to the capillary mixing unit (4), and the capillary mixing unit (4) is used to mix the received coating and supercritical carbon dioxide, and spray the mixed coating through the spray gun (1).
2. A variable volume supercritical carbon dioxide spraying device according to claim 1, characterized in that: It also comprises a supercritical carbon dioxide selection unit (5), through which supercritical carbon dioxide with different flow rates is selected to be fed to the capillary mixing unit (4).
3. A variable volume supercritical carbon dioxide spraying device according to claim 1, characterized in that: The variable volume supercritical carbon dioxide unit (2) comprises a carbon dioxide cylinder (21), a carbon dioxide temperature regulating unit (22), a variable volume carbon dioxide chamber (23) and a carbon dioxide control unit (24); the carbon dioxide cylinder (21) provides carbon dioxide to the variable volume carbon dioxide chamber (23) via a first solenoid valve (25), the carbon dioxide temperature regulating unit (22) is used to regulate the temperature of the variable volume carbon dioxide chamber (23), and the carbon dioxide control unit (24) is used to control the pressure of the variable volume carbon dioxide chamber (23).
4. A variable volume supercritical carbon dioxide spraying device according to claim 1, characterized in that: The variable volume coating unit (3) comprises a coating tank (31), a coating temperature regulating unit (32), a variable volume coating cavity (33) and a coating control unit (34); the coating tank (31) provides coating to the variable volume coating cavity (33) via a second solenoid valve (35), the coating temperature regulating unit (32) is used to regulate the temperature of the variable volume coating cavity (33), and the coating control unit (34) is used to control the pressure of the variable volume coating.
5. A variable volume supercritical carbon dioxide spraying device according to claim 1, characterized in that: The supercritical carbon dioxide selection unit (5) comprises a selection control unit (51), an array of electromagnetic valves (52) and an array of capillaries (53), wherein the number of the electromagnetic valves corresponds to the number of the capillaries. The selection control unit (51) controls the conduction and closing of the electromagnetic valves, thereby controlling the supercritical carbon dioxide to flow into the capillary mixing unit (4) through different capillaries, thereby achieving the purpose of controlling the flow rate.
6. A variable volume supercritical carbon dioxide spraying device according to claim 1, characterized in that: The carbon dioxide control unit (24) comprises a carbon dioxide main control module (241), a carbon dioxide screw gear module (242), a carbon dioxide servo motor (243) and a carbon dioxide piston (244); the carbon dioxide main control module (241) is used to control the carbon dioxide servo motor (243), the carbon dioxide servo motor (243) drives the carbon dioxide screw gear module (242), and the carbon dioxide screw gear module (242) controls the movement of the carbon dioxide piston (244), thereby adjusting the volume of the variable volume carbon dioxide chamber (23) to achieve the purpose of regulating the carbon dioxide pressure.
7. A variable volume supercritical carbon dioxide spraying device according to claim 1, characterized in that: The paint control unit (34) comprises a paint main control module (341), a paint screw gear module (342), a paint servo motor (343) and a paint piston (344); the paint main control module (341) is used to control the paint servo motor (343), the paint servo motor (343) drives the paint screw gear module (342), and the paint screw gear module (342) controls the movement of the paint piston (344), thereby adjusting the volume of the variable volume paint cavity (33) to achieve the purpose of regulating the paint pressure.
8. A variable volume supercritical carbon dioxide spraying method, characterized in that: The variable volume supercritical carbon dioxide spraying device described in any one of claims 1 to 7 is realized by a variable volume supercritical carbon dioxide spraying method.
9. A variable volume supercritical carbon dioxide spraying method according to claim 1, characterized in that: Regulating the pressure and temperature of supercritical carbon dioxide and coating; regulating the pressure and flow rate of supercritical carbon dioxide through a variable volume supercritical carbon dioxide unit (2), and regulating the pressure and flow rate of coating through a variable volume coating unit (3); The supercritical carbon dioxide and the coating are mixed by selecting the flow rate of the supercritical carbon dioxide through a supercritical carbon dioxide selection unit (5) according to different flow rates of the nozzles and entering a capillary mixing unit (4) for mixing the supercritical carbon dioxide and the coating.