A wiped film evaporator suitable for use in a test apparatus

Abstract

The utility model discloses a kind of wiped film evaporators suitable for test device, it includes evaporator tank body, evaporator tank body top is equipped with top head, bottom is equipped with lower head. Rotating shaft is equipped in evaporator tank body, the upper end of rotating shaft is connected with the output end of driving motor through rotating shaft upper end fixed bearing, the lower end of rotating shaft is connected with rotating shaft fixed support through rotating shaft lower end fixed bearing;Rotating shaft is equipped with at least a pair of scrapers, each scraper is connected with rotating shaft by a pair of hangers arranged above and below through spring sleeve, the upper and lower sides of scraper are respectively equipped with square body structure, vertical to the round head nail of rotating shaft is inserted in square body structure, the end of round head nail projects on the outside surface of square body structure.The scraper in the application slightly undulates with the actual situation of tank inner wall, and always compresses scraper, guarantee that liquid film thickness is always uniform.

Description

Technical Field

[0001] This utility model relates to a scraped film evaporator suitable for experimental devices, belonging to the field of chemical evaporation technology. Background Technology

[0002] In the purification and concentration of chemical materials, scraped film evaporators have been widely used due to their advantages such as relatively large gas flow space and small pressure drop from the gas to the condenser. However, existing equipment relies solely on the installation distance between the scraper and the inner wall of the tank to achieve the desired film thickness. Some scrapers are connected to the support via hinges, which only assume that the scraper will be close to the inner wall under centrifugal force, but the film thickness still cannot be effectively controlled as required. All mechanical equipment has allowable machining errors; it is impossible to maintain a perfectly consistent installation distance between the scraper and the inner wall at any point to achieve the required film thickness. Generally, a liquid film thickness of 0.5-1.5 mm is required, and it is challenging to reduce the allowable machining error below this requirement. Especially for scraped film evaporators used in experimental setups, research requires examining the impact of different liquid film thicknesses on the evaporation effect, and a consistently constant liquid film thickness is necessary for conclusive results. Sometimes, even a liquid film thickness control of 0.1 mm is required; such high precision cannot be met simply by improving machining and installation accuracy. Therefore, there is an urgent need to improve the design and develop a scraped film evaporator suitable for experimental devices to meet scientific research needs. Summary of the Invention

[0003] The technical problem to be solved by this utility model is to provide a scraped film evaporator suitable for experimental devices.

[0004] To address the aforementioned technical problems, this utility model provides a scraped-film evaporator suitable for experimental devices. It includes an evaporator tank with a top end cap and a bottom end cap. The top end cap has a liquid inlet pipe and a gas outlet, while the bottom end cap has a liquid outlet. A rotating shaft is located within the evaporator tank. The upper end of the rotating shaft is connected to the output end of a drive motor via an upper fixed bearing, and the lower end of the rotating shaft is connected to a fixed support via a lower fixed bearing. At least one pair of scrapers are mounted on the rotating shaft. Each scraper is connected to the rotating shaft via a pair of upper and lower brackets. A square structure is located on the upper and lower sides of each scraper, with a round-headed nail inserted perpendicular to the rotating shaft within the square structure. The end of the round-headed nail protrudes from the outer surface of the square structure. Both ends of the fixed support for the rotating shaft are connected to a double-sided sealing flange, which is clamped between the lower flange and the lower end cap flange of the evaporator tank for fixation. The number of scrapers is determined by process requirements and material characteristics. Depending on the process requirements, the scraper can be set vertically or slightly tilted, so that the concentrated liquid flows quickly to the bottom of the evaporator under the push of the scraper.

[0005] Preferably, the scraper has a bracket sleeve on its inner side; the bracket sleeve is fitted onto the outer side of the bracket, and the upper side of the outer end of the bracket has a cylinder for abutting against the bracket sleeve; a spring is fitted around the inner end of the bracket, and the two ends of the spring are connected to the rotating shaft and the bracket sleeve, respectively. A 3-5mm space is left between the inner side of the spring and the bracket. The strength of the spring must ensure that the scraper is always in close contact with the inner wall of the evaporator tank. A space of about 3mm is left between the bottom surface of the bracket sleeve and the lower surface of the bracket. The strength of the scraper's spine must ensure that it does not deform during rotation, and it is detachably connected to the bracket sleeve. A 5-10mm gap is maintained between the outer end of the bracket and the spine of the scraper.

[0006] Preferably, the outer surface of the square structure is an arc surface. A circular hole penetrating the square structure is opened at the center of the top of the arc surface. Before installing the scraper, a round-headed nail is installed in the circular hole. The round-headed nail is made of wear-resistant material.

[0007] Preferably, the length of the round-headed nail protruding from the outer surface of the square structure is the required liquid film thickness for the test.

[0008] Preferably, an inclined blade is provided on the rotating shaft inside the evaporator tank, above the scraper.

[0009] More preferably, the slant propeller has four or six blades, with the blades pointing downwards.

[0010] Preferably, the evaporator tank is provided with a heating jacket, and the heating surface of the heating jacket covers the moving surface of the scraper.

[0011] Preferably, a demister is provided at the inlet end of the gas outlet.

[0012] Preferably, the lower end cap is a conical end cap; the drive motor is positioned above the top end cap.

[0013] Preferably, after the end of the liquid feed pipe enters the top end cap, it first extends horizontally above the scraper, then extends in an arc towards the inner wall of the evaporator tank; the end of the liquid feed pipe is beveled, with the opening facing the inner wall of the evaporator tank. The inner wall of the evaporator tank is polished. The connection between the liquid feed pipe and the connector on the top end cap allows for the selection of a suitable pipe diameter according to the feed flow rate, enabling the liquid to flow out of the pipe at a suitable flow rate and be distributed along the tangential direction of the inner wall of the tank.

[0014] Currently, most experimental setups use scraped film evaporators where the scraper and rotating shaft are fixedly connected. The liquid film thickness depends entirely on the installation distance between the scraper edge and the inner wall of the tank. Due to manufacturing errors, fixed scraper connections cannot guarantee a consistently uniform liquid film thickness. Furthermore, the rigid, fixed connection requires a deliberate gap to prevent the scraper from scraping the tank wall, making it difficult to conduct thin-film testing and impossible to adjust the film thickness according to experimental requirements. The scraper in this invention uses a spring connection, allowing it to slightly undulate with the actual conditions of the tank's inner wall while maintaining constant pressure, ensuring a consistently uniform liquid film thickness. By replacing the round-headed pins with different protrusion heights at both ends of the scraper, the experimental requirements for different liquid film thicknesses can be met. Attached Figure Description

[0015] Figure 1 A perspective view of the scraped film evaporator provided by this utility model;

[0016] Figure 2 This is a top view of a rectangular structure.

[0017] Figure 3 This is a top view of the liquid feed pipe on the top end cap. Detailed Implementation

[0018] To make this utility model more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings.

[0019] Example

[0020] like Figure 1 As shown, this utility model provides a scraped film evaporator suitable for experimental devices, which includes an evaporator tank 1. The top of the evaporator tank 1 is provided with a top end cap 4 and the bottom is provided with a bottom end cap 20. The top end cap 4 is provided with a liquid feed pipe 3 and a gas outlet 6. The bottom of the bottom end cap 20 is provided with a liquid outlet 21. A rotating shaft 8 is provided inside the evaporator tank 1. The upper end of the rotating shaft 8 is connected to the output end of the drive motor 5 through a rotating shaft upper end fixed bearing 22. To prevent the lower end of the rotating shaft 8 from swinging during rotation, the lower end of the rotating shaft 8 is connected to the rotating shaft fixed support 10 through a rotating shaft lower end fixed bearing 11. A pair of scrapers 16 are provided on the rotating shaft 8. Each scraper 16 is connected to the rotating shaft 8 through a pair of hanging brackets set at the top and bottom. Square structures 19 are provided on the upper and lower sides of the scraper 16 respectively. Round-headed nails 15 perpendicular to the rotating shaft 8 are inserted into the square structures 19. The ends of the round-headed nails 15 protrude from the outer surface of the square structures 19. The two ends of the rotating shaft fixed support 10 are respectively connected to a double-sided sealing flange, which is clamped between the lower flange and the lower head flange of the evaporator tank 1 for fixation. The number of scrapers 16 is determined by the process requirements and material characteristics. According to the process requirements, the scrapers 16 can be set vertically or slightly inclined, so that the concentrated liquid flows quickly to the bottom of the evaporator under the push of the scrapers 16.

[0021] Due to inherent manufacturing errors, the inner wall of the evaporator tank and the rotating shaft cannot be perfectly concentric. Relying solely on the installation distance between the scraper and the tank's inner wall to ensure the liquid film thickness is too difficult; therefore, a flexible connection must be used between the scraper and the rotating shaft. A bracket sleeve 13 is provided on the inner side of the scraper 16. The bracket sleeve 13 is fitted onto the outer side of the bracket, and the upper side of the outer end (square end 17) of the bracket has a cylinder 14 (approximately 2-3 mm high) to abut against the bracket sleeve 13. A spring 12 is fitted over the inner end (circular end 18) of the bracket, with both ends of the spring 12 connected to the rotating shaft 8 and the bracket sleeve 13, respectively. A 3-5 mm space is left between the inner side of the spring and the bracket. The spring 12 cannot be too soft to prevent the scraper 16 from jumping off the tank's inner wall when rotating with the shaft. The scraper 16 must remain firmly against the tank's inner wall at all times under the action of the spring 12. The top surface of the hanger sleeve 13 rests on the cylinder 14 on the upper surface of the square end 17. The inner side of the hanger sleeve 13 is slightly wider than the square end 17 to ensure that the hanger sleeve 13 can slide along the hanger. A space of about 3mm is left between the bottom surface of the hanger sleeve 13 and the lower surface of the hanger to facilitate the up-and-down rotation of the hanger sleeve 13. The strength of the spine of the scraper 16 must ensure that it does not deform during rotation, and it is detachably connected to the hanger sleeve 13. A gap of 5-10mm is maintained between the square end 17 and the spine of the scraper so that when encountering irregular upper and lower dimensions of the inner wall of the tank, the scraper 16 can tilt appropriately or extend and retract horizontally within a certain range under the action of the spring 12. The spine of the scraper 16 (i.e., the inner side facing the rotation axis 8) is relatively wide, while the plate surface near the inner wall of the tank is very narrow, thereby ensuring that the liquid film thickness formed by the scraper 16 on the inner wall of the tank is uniform.

[0022] like Figure 2 As shown, the outer surface of the rectangular structure 19 is curved, and the top of the curved surface is flush with the surface of the scraper 16. A circular hole penetrating the rectangular structure is opened at the center of the top of the curved surface. Before installing the scraper, a round-headed nail is installed in the circular hole. The round-headed nail is made of wear-resistant material to ensure that the wear meets the requirements during the test cycle. The length of the round-headed nail 15 protruding from the outer surface of the rectangular structure 19 is the required liquid film thickness for the test. The nail head height of the round-headed nail 15 can be processed to different heights to adapt to the test requirements for different liquid film thicknesses.

[0023] The evaporator tank 1 is provided with a heating jacket 2, and the heating surface of the heating jacket 2 covers the moving surface of the scraper 16.

[0024] The gas outlet 6 is equipped with a demister 7 with a small pressure drop at its inlet end.

[0025] An inclined blade 9 is mounted on the rotating shaft 8 inside the evaporator tank 1, above the scraper 16. The inclined blade 9 is located between the demister at the outlet and the rotating scraper. The inclined blade 9 has four or six blades, with the blade surface pointing downwards. When rotating with the shaft, it can centrifuge and remove liquid from the evaporated gas. The liquid droplets that coalesce on the blades are thrown onto the tank wall by centrifugal force for further film evaporation.

[0026] The lower end cap 20 is a conical end cap. After the liquid feed is evaporated by the scraper, it flows through the conical surface to the bottom liquid outlet 21. The drive motor 5 is located above the top end cap 4.

[0027] like Figure 3 As shown, after the end of the liquid feed pipe 3 enters the top end cap 4, it first extends horizontally above the scraper 16, and then extends in an arc towards the inner wall of the evaporator tank 1. The end of the liquid feed pipe 3 is beveled, with the opening facing the inner wall of the evaporator tank 1. The inner wall of the evaporator tank needs to be polished to reduce wear on the round-headed nails 15 and ensure a constant liquid film thickness during the test. The liquid feed pipe 3 is connected to the connector on the top end cap 4, and a suitable pipe diameter can be selected according to the feed flow rate, so that the liquid flows out of the pipe at a suitable flow rate and is distributed along the tangential direction of the inner wall of the tank.

Claims

1. A scraped-film evaporator suitable for experimental apparatus, characterized in that, The evaporator tank (1) includes a top end cap (4) and a bottom end cap (20). The top end cap (4) has a liquid inlet pipe (3) and a gas outlet (6), while the bottom end cap (20) has a liquid outlet (21). The evaporator tank (1) contains a rotating shaft (8). The upper end of the rotating shaft (8) is connected to the output end of the drive motor (5) via a fixed bearing (22) at the upper end of the rotating shaft. The lower end of the rotating shaft (8) is connected to the output end of the drive motor (5) via a rotating shaft. The lower end of the shaft is fixed bearing (11) and fixed support (10) of the rotating shaft; at least one pair of scrapers (16) are provided on the rotating shaft (8), each scraper (16) is connected to the rotating shaft (8) through a pair of hanging brackets set above and below, and square structures (19) are provided on the upper and lower sides of the scraper (16), and round-headed nails (15) perpendicular to the rotating shaft (8) are inserted in the square structure (19), and the end of the round-headed nail (15) protrudes from the outer surface of the square structure (19).

2. The scraped-film evaporator suitable for experimental apparatus as described in claim 1, characterized in that, The scraper (16) has a hanging sleeve (13) on its inner side; the hanging sleeve (13) is sleeved on the outer side of the hanging frame, and the upper side of the outer end of the hanging frame has a cylinder (14) for abutting the hanging sleeve (13); the inner end of the hanging frame is sleeved with a spring (12), and the two ends of the spring (12) are respectively connected to the rotating shaft (8) and the hanging sleeve (13).

3. The scraped-film evaporator suitable for experimental apparatus as described in claim 1, characterized in that, The outer surface of the square structure (19) is an arc surface.

4. The scraped-film evaporator suitable for experimental apparatus as described in claim 1 or 3, characterized in that, The length of the round-headed nail (15) protruding from the outer surface of the square structure (19) is the required liquid film thickness for the test.

5. The scraped-film evaporator suitable for experimental apparatus as described in claim 1, characterized in that, An inclined blade (9) is provided on the rotating shaft (8) inside the evaporator tank (1) above the scraper (16).

6. The scraped-film evaporator suitable for experimental apparatus as described in claim 5, characterized in that, The oblique propeller (9) has four or six blades, and the blades of the oblique propeller (9) are obliquely downward.

7. The scraped-film evaporator suitable for experimental apparatus as described in claim 1, characterized in that, The evaporator tank (1) is provided with a heating jacket (2), and the heating surface of the heating jacket (2) covers the moving surface of the scraper (16).

8. The scraped-film evaporator suitable for experimental apparatus as described in claim 1, characterized in that, A demister (7) is provided at the inlet end of the gas outlet (6).

9. The scraped-film evaporator suitable for experimental apparatus as described in claim 1, characterized in that, The lower end cap (20) is a conical end cap; the drive motor (5) is located above the top end cap (4).

10. The scraped-film evaporator suitable for experimental apparatus as described in claim 1, characterized in that, After the end of the liquid feed pipe (3) enters the top sealing head (4), it first extends horizontally above the scraper (16), and then extends in an arc towards the inner wall of the evaporator tank (1); the end of the liquid feed pipe (3) is oblique, and the opening face faces the inner wall of the evaporator tank (1).

Images