A PEEK post-processing device

Abstract

This utility model relates to the field of post-processing technology for polyetheretherketone (PEEK) materials, specifically a PEEK post-processing device. The device includes a high-pressure heating chamber, a hydraulic crushing system, a high-pressure washing system, a closed-loop nitrogen drying system, a filtration and recovery system, and an external crushing device. The high-pressure heating chamber is a double-jacketed pressure vessel with a built-in heat-conducting oil heating chamber to ensure that the material is processed at a temperature of 60-90℃. The hydraulic crushing system uses a hydraulic pump to drive the pressure plate, directly crushing the not-fully-cooled PEEK material at high temperature and recovering solvents such as diphenyl sulfone. Subsequently, the built-in crushing device is activated, and the stirring shaft and stirring scraper crush the cake-like material to a particle size of less than 1mm. The high-pressure washing system uses methanol or ethanol as a single solvent, applying pressure through a high-pressure pump for washing. The closed-loop nitrogen drying system introduces hot nitrogen through a nitrogen pipeline to purge and dry the material.

Description

Technical Field

[0001] This utility model relates to the field of post-processing technology for polyether ether ketone (PEEK) materials, specifically to a PEEK post-processing device. Background Technology

[0002] During the PEEK polymerization process, due to the high degree of cross-linking and crystallization of the molecular chains, the resulting crude products generally exhibit high hardness, with a Shore hardness typically greater than or equal to 85D. In traditional processes, these materials must first be cooled to room temperature (below 25°C) before being crushed using a pulverizer. After crushing, acetone washing is required to remove diphenyl sulfone, followed by water washing to remove sodium fluoride or potassium fluoride, and finally methanol washing to improve the material's drying properties. However, the traditional centrifuge washing process reveals several serious drawbacks: low crushing efficiency; cooling and crushing are performed in separate steps, resulting in a cumbersome and lengthy process; and mechanical impurities are easily introduced during crushing, adversely affecting product purity.

[0003] Poor washing results: The centrifugal pressure provided by the centrifuge is relatively insufficient, with the equivalent pressure generally less than or equal to 1.5 MPa. This results in a moisture content of 20%-30% for the solids after a single wash. To achieve the desired purity, it is often necessary to repeat the washing process more than 10 times, which consumes a great deal of time and resources.

[0004] Severe solvent dependence: It is necessary to strictly adopt a multi-solvent combination of acetone-water-methanol or ethanol, which not only leads to an extremely large total solvent consumption, but also makes the solvent recovery process complex and costly.

[0005] High environmental pollution risk: Solvent evaporation is a significant issue during centrifugation, resulting in substantial waste gas emissions. Furthermore, insufficient equipment sealing poses a high risk of solvent leakage, posing a potential threat to the environment and production safety. Utility Model Content

[0006] (a) Technical problems to be solved

[0007] To address the shortcomings of existing technologies, this utility model provides a PEEK post-processing device.

[0008] (II) Technical Solution

[0009] To achieve the above objectives, this utility model provides the following technical solution: A PEEK post-processing device of this utility model includes a high-temperature, high-pressure, six-in-one processing device. The high-temperature, high-pressure, six-in-one processing device includes a high-pressure resistant heating chamber, a hydraulic crushing system, a high-pressure washing system, a closed-loop nitrogen drying system, a filtration and recovery system, and an external crushing device. The high-pressure resistant heating chamber is a double-jacketed pressure vessel with a built-in heat-conducting oil heating chamber. The hydraulic crushing system is installed at the top of the high-pressure heating chamber. A feed pipe is provided at the top of the high-pressure resistant heating chamber. Filtration and recovery pipes are provided at both the top and bottom of the high-pressure resistant heating chamber. The high-pressure washing system is connected to the feed pipe via a conveying pipe. The closed-loop nitrogen drying system is connected to the feed pipe via a nitrogen pipe. The closed-loop nitrogen drying system is connected to the filtration and recovery pipe via a nitrogen recovery pipe. The external crushing device is connected to the high-pressure resistant heating chamber via a conveying pipe. The external crushing device is connected to the feed pipe via a circulation pipe, and a circulation pump is installed on the circulation pipe.

[0010] Preferably, the hydraulic crushing system includes a hydraulic pump and a pressure plate. The hydraulic pump is installed at the top of the high-pressure heat treatment chamber, and the pressure plate is located inside the high-pressure heat treatment chamber and installed at the output end of the hydraulic pump.

[0011] More preferably, the bottom of the high-pressure heat treatment chamber is equipped with a built-in crushing device, which includes a screw jack, a stirring shaft, and a stirring scraper. The screw jack is fixedly installed at the bottom of the high-pressure heat treatment chamber, the stirring shaft is fitted onto the screw output end of the screw jack and extends into the interior of the high-pressure heat treatment chamber, and the stirring scraper is fixedly installed at the output end of the stirring shaft.

[0012] Preferably, a discharge pipe is installed at the bottom of the high-pressure heat treatment chamber, an air pump is fixedly installed at one end of the discharge pipe, the output end of the air pump extends into the discharge pipe, and a sealing plug is installed at the output end of the air pump. A discharge port is provided at the bottom of the discharge pipe, and a discharge hopper is installed on the discharge port.

[0013] Preferably, the bottom two ends of the high-pressure heat treatment chamber are provided with a heat inlet pipe and a heat outlet pipe, and the side wall of the high-pressure heat treatment chamber is provided with a heat outlet pipe.

[0014] More preferably, a sintered filter screen is installed inside the filter recovery pipe, and the filter recovery pipe is a spiral backflushing pipe.

[0015] Preferably, the nitrogen recovery pipe is equipped with a solution recovery pipe, and both the nitrogen recovery pipe and the solution recovery pipe are equipped with high-pressure pumps.

[0016] Preferably, the high-pressure washing system includes at least four solution tanks for storing hot water, acetone, PEEK material, and methanol or ethanol cleaning solution. A high-pressure pump is installed at the connection between the solution tank and the conveying pipeline, and a high-pressure pump is installed at the connection between the nitrogen pipeline and the circulation pipeline and the feed pipeline.

[0017] (III) Beneficial Effects

[0018] Compared with the prior art, the present invention provides a PEEK post-processing device, which has the following beneficial effects:

[0019] This technical solution is based on a PEEK post-processing method and its dedicated device—a high-temperature and high-pressure six-in-one processing device—which integrates high-temperature crushing, high-pressure washing, and efficient solvent utilization. This device significantly improves the post-processing efficiency and quality of PEEK materials by integrating multiple functional modules.

[0020] High-efficiency crushing and solvent recovery

[0021] High-temperature crushing system: A hydraulic pump drives the pressure plate to directly crush incompletely cooled PEEK material at a high temperature of 300-340℃, eliminating the cooling step in traditional processes and significantly improving processing efficiency. Simultaneously, this process effectively recovers solvents such as diphenyl sulfone, reducing resource waste.

[0022] Built-in crushing device: The screw lifting motor drives the stirring shaft and stirring scraper to ensure that the cake material is quickly crushed to a particle size of less than 1mm, avoiding the introduction of mechanical impurities and improving product purity;

[0023] High-pressure washing optimization

[0024] Single solvent washing: At a temperature of 60-90℃, methanol or ethanol is used as the single solvent, and a pressure of 20-30MPa is applied by a high-pressure pump for washing. After a single wash, the moisture content of the solids is less than 10%. Compared with the traditional centrifuge process (moisture content as high as 20%-30%), the number of washing times is significantly reduced (from 12 times to 5-6 times), which greatly improves production efficiency.

[0025] Multi-solvent stepwise washing: When the inorganic salt content in the material is high, acetone (preferably 60°C) is used first to remove diphenyl sulfone, then hot water (preferably 80°C) is used to remove fluoride salts, and finally methanol is used for displacement drying, which ensures thorough removal of impurities and improves product quality.

[0026] Green and environmentally friendly production

[0027] Closed-loop nitrogen drying system: Hot nitrogen at 100-120℃ is introduced through nitrogen pipeline to purge and dry the material, and nitrogen is recovered through nitrogen recovery pipe to form a closed loop, which effectively reduces solvent evaporation and exhaust emissions, meets the requirements of GB37822-2019 "Standard for the Control of Unorganized Emissions of Volatile Organic Compounds", and realizes green manufacturing.

[0028] High-efficiency filtration and solvent recovery

[0029] Filtration and recovery system: The sintered filter screen intercepts impurities, and the spiral backflush pipeline is periodically purged with high-pressure hot nitrogen to prevent filter pore blockage and ensure smooth filtration. A high-pressure pump is installed at the connection between the solution tank and the delivery pipeline to ensure efficient solvent recovery and reuse, thereby reducing production costs. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the high-temperature and high-pressure six-in-one processing device of this utility model;

[0031] In the diagram: 1. High-pressure heat treatment chamber; 2. Solution tank; 3. Closed-loop nitrogen drying system; 4. External crushing device; 5. Screw jack; 6. Hydraulic pump; 7. Pressure plate; 8. Stirring shaft; 9. Stirring scraper; 10. Feed pipe; 11. Filter recovery pipe; 12. Solution recovery pipe; 13. Nitrogen pipe; 14. Circulation pump; 15. Conveying pipe; 16. Circulation pipe; 17. High-pressure pump; 18. Material conveying pipe; 19. Heat transfer oil heating chamber; 20. Heating inlet pipe; 21. Heating outlet pipe; 22. Nitrogen recovery pipe; 23. Discharge pipe; 24. Air pump; 25. Sealing plug; 26. Discharge hopper. Detailed Implementation

[0032] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0033] Please see Figure 1This utility model discloses a PEEK post-processing device, comprising a high-temperature and high-pressure six-in-one processing unit. The high-temperature and high-pressure six-in-one processing unit includes a high-pressure resistant heating chamber 1, a hydraulic crushing system, a high-pressure washing system, a closed-loop nitrogen drying system 3, a filtration and recovery system, and an external crushing device 4. The high-pressure resistant heating chamber 1 is a double-jacketed pressure vessel, with a built-in heat-conducting oil heating chamber 19. The hydraulic crushing system is installed at the top of the high-pressure heating chamber. A feed pipe 10 is provided at the top of the high-pressure resistant heating chamber 1. The high-pressure heat treatment chamber 1 is equipped with filter recovery pipes 11 at both the top and bottom. The high-pressure washing system is connected to the feed pipe 10 through the conveying pipe 15. The closed nitrogen drying system 3 is connected to the feed pipe 10 through the nitrogen pipe 13. The closed nitrogen drying system 3 is connected to the filter recovery pipe 11 through the nitrogen recovery pipe 22. The external crushing device 4 is connected to the high-pressure heat treatment chamber 1 through the conveying pipe 18. The external crushing device 4 is connected to the feed pipe 10 through the circulation pipe 16. The circulation pipe 16 is equipped with a circulation pump 14.

[0034] This technical solution achieves integrated post-processing of PEEK materials through a high-temperature, high-pressure, six-in-one processing device. The core logic is to use high-temperature crushing to eliminate the cooling step, high-pressure washing to enhance impurity removal, and a closed system to achieve solvent recovery and green drying. The device is centered on a high-pressure resistant heating chamber 1, integrating hydraulic crushing, internal / external crushing, high-pressure washing, filtration and recovery, and closed-loop nitrogen drying systems. Through the coordinated operation of each module, the traditional step-by-step process is integrated into a continuous process, realizing the efficient conversion of PEEK materials from high-temperature crude products to high-purity dried finished products.

[0035] High-pressure heat treatment chamber 1

[0036] Double-layer jacketed heating principle: The double-layer jacketed pressure vessel is made of 316L stainless steel. The inner layer contains the material, and the outer layer is a heat transfer oil heating chamber 19. High-temperature heat transfer oil (100-150℃) is introduced into the industrial heating hot oil storage container through the heating inlet pipe 20. The heat transfer oil circulates (the heating outlet pipe 21 is connected to the industrial heating hot oil storage container for return flow) to stabilize the temperature inside the chamber at 60-90℃, preventing the PEEK material from hardening due to cooling, and providing a constant temperature environment for washing and drying.

[0037] Pressure-resistant and sealing design: The cavity is designed for a pressure of ≥35MPa, and the inner wall is coated with a PEEK coating (thickness 0.2-0.5mm) to prevent material contamination and enhance corrosion resistance, adapting to the high-temperature impact of initial materials at 300-340℃.

[0038] Hydraulic crushing system

[0039] High-pressure compaction principle: The hydraulic pump 6 drives the pressure plate 7 to move downward in the cavity, applying a pressure of 5-10MPa (converted from the output pressure of the hydraulic pump 6), pressing the high-temperature PEEK material (300-340℃) into a cake shape, extruding and recovering solvents such as diphenyl sulfone (discharged through the solution recovery pipe 12 connected to the top or bottom filter recovery pipe 11 of the high-pressure heat treatment chamber 1 in conjunction with the high-pressure pump 17).

[0040] Anti-sticking and efficient pressing: The surface roughness Ra of the pressing plate 7 is ≤0.8μm, which reduces material adhesion. Combined with the high temperature environment, the solvent fluidity is enhanced. After pressing, the moisture content of the material is reduced to below 15%, which lays the foundation for subsequent crushing.

[0041] Crushing devices (built-in + external)

[0042] Built-in crushing device:

[0043] The screw jack 5 drives the mixing shaft 8 to rotate (300-500 rpm), and the mixing scraper 9 (made of tungsten carbide) rotates with the shaft to crush the pressed cake material to a particle size ≤1mm.

[0044] The axial feed function (stroke 50-100mm) of the screw jack can adjust the distance between the scraper and the bottom of the chamber to avoid material accumulation and ensure uniform crushing.

[0045] External crushing device 4:

[0046] The material crushed by the built-in crusher enters the external crushing device 4 through the conveying pipe 18. Driven by the circulating pump 14 (pressure 0.5-1MPa), it is mixed with the ethanol cleaning liquid (solid-liquid ratio 1:3) and crushed by external shearing to a particle size ≤5μm. The external crushing can be any one of a horizontal bead mill with ultra-fine crushing capacity or a high-speed shear crusher.

[0047] After crushing, the slurry is returned to the high-pressure heating chamber 1 via the circulation pipe 16, so as to achieve "crushing-cleaning" at the same time and remove some of the impurities attached to the surface.

[0048] High-pressure washing system

[0049] Single solvent washing principle: High-pressure pump 17 injects methanol / ethanol (at a rate of 1-2 times the material mass) at 50-70℃ into the chamber, raising the pressure to 20-30MPa. Under high temperature and pressure, the solvent penetration is increased by 3 times, simultaneously dissolving diphenyl sulfone and wetting fluoride salt crystals. The solution is then rapidly separated through a sintered filter mesh (pore size ≤10μm), achieving a moisture content ≤10% in a single wash.

[0050] Multi-solvent stepwise washing principle (high-salt scenario):

[0051] Acetone (preferably 60°C) preferentially dissolves diphenyl sulfone, and the solution is discharged through the solution recovery pipe 12 connected to the filter recovery pipe 11 in conjunction with the high-pressure pump 17;

[0052] Hot water (preferably 80℃) utilizes high temperature to increase the solubility of sodium fluoride (30% higher than at 25℃), thereby enhancing salt removal;

[0053] Methanol replaces residual moisture, reducing subsequent drying energy consumption.

[0054] Closed-loop nitrogen drying system 3

[0055] Hot nitrogen purging principle: 100-120℃ hot nitrogen enters the chamber through nitrogen pipeline 13 and purges the material at a flow rate of 0.5-1m / s, carrying away the surface solvent; nitrogen carrying vapor enters nitrogen recovery pipe 22 through filter recovery pipe 11 in conjunction with high pressure pump 17. After condensation and separation, nitrogen is recycled (recovery rate ≥95%), and solvent enters solution recovery pipe 12 connected to filter recovery pipe 11 in conjunction with high pressure pump 17.

[0056] Deep drying control: The moisture content is monitored by an online moisture meter, and the drying process automatically stops when it drops below 1%, avoiding overheating that could lead to material degradation.

[0057] The closed-loop nitrogen drying system 3 in this technical solution can be either a horizontal nitrogen circulation dryer or a closed-loop hot air circulation dryer.

[0058] Filtration and Recycling System

[0059] High-efficiency separation principle: The filter sintered mesh (such as a multi-layer sintered mesh made of 316L stainless steel, 1-15μm) is installed on the filter recovery pipe 11 to intercept PEEK particles. The filter recovery pipe 11 adopts a spiral backflush pipeline (closed nitrogen drying system 3 purges with 1MPa hot nitrogen for 30 seconds every 10 minutes) to prevent clogging and ensure stable filtration throughput.

[0060] Solvent recovery process: The filtrate is processed by a condensation-phase separation device, and the purity of solvents such as diphenyl sulfone and methanol is ≥98%, which can be directly reused, reducing raw material consumption.

[0061] Detailed Workflow

[0062] Equipment startup and pretreatment

[0063] Turn on the heat transfer oil heating system and raise the temperature of the high-pressure heat treatment chamber 1 to 60-90℃ through the heating inlet / outlet pipes to maintain the temperature stability of the double jacket.

[0064] Check the sealing of all pipes and valves to ensure that the high-pressure washing system and the closed-loop nitrogen drying system 3 are unobstructed in connection with the cavity.

[0065] The external crushing device 4 is injected with ethanol cleaning solution, and the circulating pump 14 is adjusted to the working pressure (0.5MPa).

[0066] High-temperature crushing and preliminary crushing (Step 1)

[0067] Feeding: PEEK high-temperature crude product at 300-340℃ is continuously fed into the high-pressure heat treatment chamber 1 through the feed pipe 10. Feeding is stopped after the batch quantity (70% of the chamber volume) is reached.

[0068] Hydraulic pressing: Start hydraulic pump 6, press plate 7 descends at a speed of 50mm / min, apply 5-10MPa pressure to squeeze the material, recover diphenyl sulfone solvent (discharged through top filter recovery pipe 11), continue for 30 minutes until the material is in cake form;

[0069] Built-in crushing: The screw jack 5 drives the mixing shaft 8 to rotate (300 rpm), and the mixing scraper 9 crushes the cake-shaped material to a particle size ≤1 mm in 20 minutes.

[0070] External ultrafine crushing: The material enters the external crushing device 4 through the conveying pipe 18, is mixed with ethanol and crushed to ≤5μm, and then flows back to the cavity through the circulation pipe 16. It is simultaneously cleaned for 30 minutes, and then the hydraulic pump 6 is restarted to dry it (moisture content controlled at 5-10%).

[0071] Solvent washing (Step 2 / Step 3)

[0072] Single solvent washing:

[0073] High-pressure pump 17 injects methanol at 50-70℃ (1.5 times the mass of the material) into the chamber, pressurizes it to 20-30MPa within 3 minutes, and holds the pressure for 8 minutes;

[0074] Open the bottom filter recovery tube 11. The filtrate is separated by the filter sintering mesh. The moisture content is detected to be ≤10%, and a single washing is completed. Repeat the operation 5 times until the purity meets the standard.

[0075] Multi-solvent stepwise washing (enabled on demand):

[0076] First wash: Wash with acetone (twice the mass of the material) at 60℃ and 10MPa pressure for 10 minutes to remove diphenyl sulfone;

[0077] Second wash: Wash with 80℃ hot water (1.2 times the mass of the material) at 10MPa pressure for 5 minutes to reduce the fluoride content (filtrate conductivity ≤150μS / cm);

[0078] Third: Methanol (1 times the mass of the material) is used for displacement under a pressure of 20 MPa, with a moisture content of ≤10%.

[0079] Continuous drying (step 4)

[0080] Nitrogen purging: The closed nitrogen drying system 3 is purged with hot nitrogen at 100-120℃, with the flow rate controlled at twice the volume of the chamber per hour. The purging time is 60 minutes, and the moisture content is reduced to below 5%.

[0081] Deep drying: Activate closed drying mode, reduce nitrogen flow rate to 0.5 times / hour, continue for 30 minutes, moisture content ≤1%;

[0082] Nitrogen recovery: Nitrogen containing solvent vapor is condensed through filter recovery pipe 11, high pressure pump 17 and nitrogen recovery pipe 22. The solvent enters solution recovery pipe 12 through filter recovery pipe 11 and high pressure pump 17, and nitrogen is recycled.

[0083] Discharge and cleaning

[0084] When the air pump 24 is started, the seal blockage 25 is pulled out from the discharge pipe 23. At the same time, the screw jack 5 drives the mixing scraper 9 to push the material to the discharge pipe 23. In actual use, the air pump 24 can be replaced by a hydraulic telescopic pump, which has the same function as the air pump 24.

[0085] The material falls into the discharge hopper 26 through the discharge port, completing the collection process;

[0086] The chamber and pipes are flushed with a mixture of clean water and methanol (1:1). The waste liquid is discharged after being treated by the filtration and recovery system, and the equipment is put into standby mode.

[0087] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A PEEK post-processing device, characterized in that, The device includes a high-temperature and high-pressure six-in-one treatment unit, comprising a high-pressure resistant heating treatment chamber (1), a hydraulic crushing system, a high-pressure washing system, a closed-loop nitrogen drying system (3), a filtration and recovery system, and an external crushing device (4). The high-pressure resistant heating treatment chamber (1) is a double-layer jacketed pressure vessel with a built-in heat transfer oil heating chamber (19). The hydraulic crushing system is installed at the top of the high-pressure heating treatment chamber. The top of the high-pressure resistant heating treatment chamber (1) is provided with a feed pipe (10). The top and bottom of the high-pressure resistant heating treatment chamber (1) are both equipped with... There is a filter recovery pipe (11). The high-pressure washing system is connected to the feed pipe (10) through the conveying pipe (15). The closed nitrogen drying system (3) is connected to the feed pipe (10) through the nitrogen pipe (13). The closed nitrogen drying system (3) is connected to the filter recovery pipe (11) through the nitrogen recovery pipe (22). The external crushing device (4) is connected to the high-pressure heat treatment chamber (1) through the conveying pipe (18). The external crushing device (4) is connected to the feed pipe (10) through the circulation pipe (16). The circulation pipe (16) is equipped with a circulation pump (14).

2. The PEEK post-processing device according to claim 1, characterized in that, The hydraulic crushing system includes a hydraulic pump (6) and a pressure plate (7). The hydraulic pump (6) is installed at the top of the high-pressure heat treatment chamber (1), and the pressure plate (7) is located inside the high-pressure heat treatment chamber (1) and installed at the output end of the hydraulic pump (6).

3. The PEEK post-processing device according to claim 1, characterized in that, The bottom of the high-pressure heat treatment chamber (1) is equipped with a built-in crushing device, which includes a screw jack (5), a stirring shaft (8), and a stirring scraper (9). The screw jack (5) is fixedly installed at the bottom of the high-pressure heat treatment chamber (1). The stirring shaft (8) is fitted onto the screw output end of the screw jack (5) and extends into the interior of the high-pressure heat treatment chamber (1). The stirring scraper (9) is fixedly installed at the output end of the stirring shaft (8).

4. The PEEK post-processing device according to claim 1, characterized in that, The bottom of the high-pressure heat treatment chamber (1) is equipped with a discharge pipe (23), and an air pump (24) is fixedly installed at one end of the discharge pipe (23). The output end of the air pump (24) extends into the discharge pipe (23), and a sealing plug (25) is installed at the output end of the air pump (24). The bottom of the discharge pipe (23) is provided with a discharge port, and a discharge hopper (26) is installed on the discharge port.

5. A PEEK post-processing device according to claim 1, characterized in that, The bottom two ends of the high-pressure heat treatment chamber (1) are provided with a heating inlet pipe (20) and a heating outlet pipe (21), and the side wall of the high-pressure heat treatment chamber (1) is provided with a heating outlet pipe (21).

6. The PEEK post-processing apparatus according to claim 1, characterized in that, The filter recovery pipe (11) is equipped with a filter sintered mesh and is a spiral backflush pipe.

7. A PEEK post-processing apparatus according to claim 1, characterized in that, The nitrogen recovery pipe (22) is equipped with a solution recovery pipe (12), and both the nitrogen recovery pipe (22) and the solution recovery pipe (12) are equipped with a high-pressure pump (17).

8. A PEEK post-processing apparatus according to claim 1, characterized in that, The high-pressure washing system includes at least four solution tanks (2), which are used to store hot water, acetone, PEEK material and methanol or ethanol cleaning solution. A high-pressure pump (17) is provided at the connection between the solution tank (2) and the conveying pipe (15). A high-pressure pump (17) is also provided at the connection between the nitrogen pipe (13) and the circulation pipe (16) and the feed pipe (10).

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