Film distributing head capable of stabilizing flow and forming film in falling-film evaporator
By designing a film-forming head structure with multiple speed reductions and tangential orifices, the problem of unstable feed liquid entry was solved, achieving uniform and stable distribution and spiral flow of the feed liquid in the heat exchange tube, thus improving the evaporation and separation efficiency.
Patent Information
- Application Number
- CN202520364968.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-04
- Publication Date
- 2026-01-23
- Estimated Expiration
- 2035-03-04
AI Technical Summary
In existing falling film evaporators, the film-forming head becomes unstable due to the impact force during the feed liquid entry process, which affects the film formation effect of the feed liquid and reduces the evaporation and separation efficiency.
Design a film distribution head structure including a head, a downcomer plate, an overflow plate, and a film distribution tube. Through multiple speed reductions and tangential hole designs, the liquid is stably distributed before entering the heat exchange tube. It enters the heat exchange tube in a spiral flow manner to ensure a uniform and stable liquid film thickness.
It improves the film-forming effect of the feed liquid in the heat exchange tube, enhances the evaporation and separation efficiency, ensures that the feed liquid enters the heat exchange tube uniformly and stably, and improves the evaporation and separation effect.
Smart Images
Figure CN223818187U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to heat exchange evaporation equipment especially membrane head that can steady flow film formation in falling film evaporator. BACKGROUND
[0002] Falling film evaporator is a kind of high-efficiency evaporation equipment, and the core structure design aims at realizing the efficient evaporation and separation of liquid film. The feed liquid is added from the head of the falling film evaporator, and the feed liquid is uniformly distributed into each heat exchange tube under the flow guiding effect of the membrane head in the head. Under the action of gravity, the liquid film formed on the inner wall of the heat exchange tube flows downward, and the high-temperature steam heats the heat exchange tube, so that the feed liquid completes evaporation and separation in the flowing process. The membrane head that can steady flow film formation in the falling film evaporator is the most important component, which ensures whether the feed liquid can form a uniform liquid film in the heat exchange tube. At present, the membrane tube in the membrane head on the market is inserted into the heat exchange tube, and a membrane gap is left between the membrane tube and the heat exchange tube. The feed liquid in the head enters the heat exchange tube from the membrane gap to form a liquid film. However, due to the continuous entry of the feed liquid into the head, the feed liquid in the head will shake under the impact force, so that the amount of feed liquid entering the membrane gap is unstable, which affects the film formation effect of the feed liquid, and finally reduces the evaporation and separation efficiency of the feed liquid. SUMMARY
[0003] The utility model aims at providing a membrane head that can steady flow film formation in falling film evaporator, which can make the feed liquid enter the heat exchange tube stably and improve the film formation effect.
[0004] To achieve the above-mentioned purpose, the utility model adopts the technical scheme of a membrane head that can steady flow film formation in falling film evaporator, comprising: a head, the head is sealingly connected with the upper tube plate of the barrel body, a plurality of heat exchange tubes are uniformly distributed in the upper tube plate, a plurality of membrane tubes are inserted into the heat exchange tubes and are uniformly distributed on the upper tube plate, the outer side wall of the membrane tube abuts against the inner side wall of the heat exchange tube, two tangent holes tangent to the inner wall are symmetrically arranged on the tube wall of the membrane tube, the bottom of the membrane tube is designed as a horn mouth that gradually opens from top to bottom, the thickness between the inner wall and the outer wall of the horn mouth gradually thins from top to bottom, a liquid falling tray is arranged above the membrane tube, a plurality of liquid falling tubes are sealingly arranged in the liquid falling tray, the liquid falling tubes are staggered with the membrane tubes, the liquid outlet end of the liquid falling tube extends downward beyond the liquid falling tray and is located below the tangent hole, an overflow hole is arranged on the liquid falling tube in the liquid falling tray, an overflow tray is arranged above the liquid falling tray, the outer diameter of the overflow tray is smaller than the inner diameter of the liquid falling tray, a plurality of liquid distribution holes are uniformly distributed on the bottom wall of the overflow tray and are staggered with the liquid falling tubes, a liquid inlet tube is sealingly arranged on the head, the liquid inlet end of the liquid inlet tube extends out of the head, the liquid outlet end of the liquid inlet tube is sealingly welded on the bottom wall of the overflow tray and is staggered with the liquid distribution holes, and a liquid outlet hole is arranged on the side wall of the liquid inlet tube.
[0005] Furthermore, in the aforementioned falling film evaporator, the film-forming head capable of stable flow has two inlet pipes symmetrically arranged on the end cap, and two outlet holes symmetrically arranged on the side wall of the inlet pipes.
[0006] Furthermore, in the aforementioned falling film evaporator, the film-forming head capable of stable flow has several ribs evenly distributed around the circumference of the outer wall of the overflow plate. The ribs are welded to the inner wall of the end cap, and the overflow plate is coaxially aligned with the end cap.
[0007] Furthermore, in the aforementioned falling film evaporator, the film-forming head capable of stable flow has several threaded tie rods welded to the circumference of the upper tube sheet, and several connecting holes evenly distributed around the circumference of the bottom wall of the downcomer. Each threaded tie rod extends into the corresponding connecting hole, and the threaded tie rod is fully welded to the connecting hole. A locking nut is threaded onto the threaded tie rod, and the locking nut is screwed and abuts against the bottom inner wall of the downcomer. The downcomer and the overflow plate are coaxially aligned vertically.
[0008] Furthermore, in the aforementioned falling film evaporator, the film-forming head capable of stable flow has four overflow holes evenly distributed around the circumference of the downcomer.
[0009] Furthermore, in the aforementioned falling film evaporator, the film-forming head capable of stable flow has two auxiliary flow holes symmetrically arranged on the wall of the film-forming tube. The two auxiliary flow holes are higher than the bottom wall of the tangential holes, and the line connecting the two auxiliary flow holes is perpendicular to the line connecting the two tangential holes.
[0010] Furthermore, in the aforementioned falling film evaporator, the membrane head capable of stable film formation has the following connection structure between the upper tube sheet, the heat exchange tube, and the membrane tube: several inverted T-shaped holes are evenly distributed in the upper tube sheet; the heat exchange tube is inserted into the large end of the inverted T-shaped hole and then welded to the upper tube sheet; the top of the heat exchange tube abuts against the inner shoulder of the inverted T-shaped hole; an outer shoulder is provided on the outer wall of the membrane tube; the membrane tube passes through the small end of the inverted T-shaped hole and is inserted into the heat exchange tube; the outer shoulder on the membrane tube abuts against the upper tube sheet and is welded to the upper tube sheet.
[0011] The advantages of this invention are as follows: when the liquid enters the overflow plate from the inlet pipe, it experiences a first reduction in speed due to the obstruction of the overflow plate; when the liquid flows from the overflow plate into the downcomer, it experiences a second reduction in speed; and when the liquid flows from the downcomer into the upper tube sheet, it experiences a third reduction in speed. These three reductions in speed ensure a stable liquid level on the upper tube sheet, allowing the liquid to enter the film distribution tube evenly and stably for film distribution. Furthermore, the symmetrically arranged tangential holes on the film distribution tube allow the liquid to enter the film distribution tube... The liquid enters the membrane tube tangentially. The liquid flows downward spirally around the axis of the membrane tube. During the spiral flow, the liquid adheres to the inner wall of the membrane tube under the action of centrifugal force and flows downward along the inner wall of the membrane tube. Since the membrane tube is inserted into the heat exchange tube, the liquid also flows in the heat exchange tube in a spiral manner after transitioning from the membrane tube to the heat exchange tube. This makes the liquid film thickness in the heat exchange tube uniform and stable, improving the membrane effect of the liquid in the heat exchange tube. Attached Figure Description
[0012] Figure 1 This is a schematic diagram of the structure of the film-forming head in the falling film evaporator of this utility model, which is capable of stable flow film formation.
[0013] Figure 2 yes Figure 1 A schematic diagram of the arrangement structure between the downcomer and the membrane distribution tube.
[0014] Figure 3 yes Figure 1 A schematic diagram of the arrangement structure between the liquid inlet pipe and the liquid distribution holes in the overflow plate.
[0015] Figure 4 yes Figure 1 A schematic diagram of the structure of the membrane tube.
[0016] Figure 5 yes Figure 4 A top view of the structure of the membrane tube.
[0017] Figure 6 yes Figure 1 A schematic diagram of the structure of the downcomer. Detailed Implementation
[0018] The technical solution of this utility model will be further described below with reference to the accompanying drawings and preferred embodiments.
[0019] like Figures 1-6As shown, the falling film evaporator of this invention, which is capable of stable film formation, includes: a sealing head 1, which is sealed to the upper tube sheet 2 of the cylinder body; a plurality of heat exchange tubes 21 are evenly distributed in the upper tube sheet 2; and a plurality of film-forming tubes 22 are evenly distributed on the upper tube sheet 2 and inserted into the heat exchange tubes 21. The connection structure between the upper tube sheet 2, the heat exchange tubes 21, and the film-forming tubes 22 is as follows: a plurality of inverted T-shaped holes are evenly distributed in the upper tube sheet 2; the heat exchange tubes 21 are inserted into the large end of the inverted T-shaped holes and then welded to the upper tube sheet 2; the top of the heat exchange tubes 21 abuts against the inner shoulder of the inverted T-shaped holes; an outer shoulder 221 is provided on the outer wall of the film-forming tubes 22; and the film-forming tubes 22 are inserted into the heat exchange tubes 21 after passing through the small end of the inverted T-shaped holes. In heat pipe 21, the outer wall of the film-coated tube 22 abuts against the inner wall of the heat exchange tube 21. The outer shoulder 221 on the film-coated tube 22 abuts against the upper tube sheet 2 and is welded to the upper tube sheet 2. This ensures that the film-coated tube 22 and the heat exchange tube 21 are coaxially aligned. Two tangential holes 222 tangential to the inner wall are symmetrically arranged on the wall of the film-coated tube 22. When the liquid flows into the film-coated tube 22 through the tangential holes 222, the liquid has an initial angular momentum due to the tangential holes 222. The liquid will enter the film-coated tube 22 along the tangential direction. The liquid flows downward spirally around the axis of the film-coated tube 22. When the liquid flows spirally, it will abut against the film-coated tube 22 under the action of centrifugal force. The liquid flows downwards along the inner wall of the membrane tube 22. Since the membrane tube 22 is inserted into the heat exchange tube 21, the liquid also flows in a spiral manner in the heat exchange tube 21 after transitioning from the membrane tube 22 to the heat exchange tube 21. To ensure that the liquid in the membrane tube 22 can transition to the heat exchange tube 21 in a stable spiral flow manner, the bottom of the membrane tube 22 is designed as a funnel-shaped opening 223 that gradually widens from top to bottom. The thickness between the inner and outer walls of the funnel-shaped opening 223 gradually decreases from top to bottom, thereby reducing the height difference between the inner wall of the membrane tube 22 and the inner wall of the heat exchange tube 21. In this embodiment, the thinnest wall at the bottom of the funnel-shaped opening 223 is 0.55 to 0.6 mm, thus enabling... To ensure that the liquid enters the heat exchange tube 21 from the membrane tube 22 without disrupting the spiral flow of the liquid due to excessive height difference, and to improve the film formation effect of the liquid in the heat exchange tube 21, two auxiliary flow holes 224 are symmetrically arranged on the wall of the membrane tube 22. The two auxiliary flow holes 224 are higher than the bottom wall of the tangential holes 222, and the line connecting the two auxiliary flow holes 224 is perpendicular to the line connecting the two tangential holes 222. When the liquid level in the end cap 1 is too high, the liquid will flow into the membrane tube 22 from the two auxiliary flow holes 224, increasing the discharge speed of the liquid. After the liquid enters the membrane tube 22 from the two auxiliary flow holes 224, it will also form a spiral flow under the action of the spiral flow of the liquid.
[0020] A downcomer plate 3 is installed in the end cap 1, located above the membrane distribution tube 22. Several threaded tie rods 23 are welded to the circumference of the upper tube sheet 2. Several connecting holes are evenly distributed on the bottom wall of the downcomer plate 3. Each threaded tie rod 23 extends into the corresponding connecting hole and is fully welded to the connecting hole. A locking nut 231 is threaded onto the threaded tie rod 23 and screwed against the bottom inner wall of the downcomer plate 3. The downcomer plate 3 is coaxially aligned with the upper tube sheet 2. Several downcomer tubes 31 are sealed in the downcomer plate 3. The downcomer tubes 31 are offset from the membrane distribution tube 22, and the liquid outlet end of the downcomer tube 31 extends downwards from the downcomer plate 3 and is located below the tangential hole 222. Four overflow holes 311 are evenly distributed around the circumference of the downcomer 31 located in the downcomer 3. When the liquid enters the downcomer 3, it will accumulate in the downcomer 3. When the liquid level in the downcomer 3 is higher than the overflow holes 311, the liquid in the downcomer 3 will be poured into the downcomer 31 from the overflow holes 311, and then flow from the downcomer 31 into the upper tube sheet 2. Since the downcomer 31 and the membrane tube 22 are misaligned, the liquid will not flow directly from the downcomer 31 into the membrane tube 22. The liquid needs to accumulate on the upper tube sheet 2. When the liquid level in the upper tube sheet 2 reaches the position of the tangential hole 222 in the membrane tube 22, the liquid will flow from the tangential hole 222 into the membrane tube 22 and flow downward spirally.
[0021] Above the downcomer 3, an overflow plate 4 is provided, coaxially aligned vertically. Several reinforcing ribs 41 are evenly distributed circumferentially on the outer wall of the overflow plate 4, welded to the inner wall of the end cap 1. The overflow plate 4 is also coaxially aligned vertically with the end cap 1. The outer diameter of the overflow plate 4 is smaller than the inner diameter of the downcomer 3. Several distributing holes 42 are evenly distributed on the bottom wall of the overflow plate 4, offset from the downcomer 31. Two inlet pipes 5 are sealed and symmetrically arranged on the end cap 1. The inlet end of the inlet pipe 5 extends out of the end cap 1, and the outlet end of the inlet pipe 5 is sealed and welded to the bottom wall of the overflow plate 4, offset from the distributing holes 42. Two outlet holes 51 are symmetrically arranged on the side wall of the inlet pipe 5. The liquid enters the overflow plate 4 from the two inlet pipes 5. Because the distribution holes 42 of the inlet pipe 5 are misaligned, the liquid in the inlet pipe 5 will impact the bottom wall of the overflow plate 4, reducing the flow velocity, and then flow out from the outlet hole 51. It will then flow from the distribution hole 42 of the overflow plate 4 into the downcomer 3. Since the distribution hole 42 and the downcomer 31 are misaligned, the liquid flowing out from the distribution hole 42 will not directly enter the downcomer 31, but will accumulate in the downcomer 3 until the liquid level in the downcomer 3 reaches the overflow hole 311 in the downcomer 31 before flowing into the downcomer 31 for discharge. When the amount of liquid entering the two inlet pipes 5 is too large, the distribution hole 42 of the overflow plate 4 cannot discharge the liquid in time, and the liquid will accumulate in the overflow plate 4. When the liquid level is higher than the overflow plate 4, it will overflow from the overflow plate 4 and enter the downcomer 3.
[0022] In use, the liquid is transported from two inlet pipes 5 to the overflow plate 4. The liquid in the inlet pipes 5 impacts the bottom wall of the overflow plate 4 for initial deceleration, and then discharges from the two outlet holes 51 of the inlet pipes 5 into the overflow plate 4. The liquid then flows downwards through the distribution holes 42 of the overflow plate 4 into the downcomer plate 3 for accumulation. When too much liquid is discharged from the inlet pipes 5 and the distribution holes 42 cannot discharge it in time, the liquid accumulates in the overflow plate 4. When the liquid level is higher than the overflow plate 4, the liquid will overflow from the overflow plate 4 into the downcomer plate 3. The liquid flows from the overflow plate 4 into the downcomer plate 3, achieving a second reduction in flow rate. At this time, the flow rate of the liquid in the downcomer plate 3 is significantly reduced. After entering the downcomer plate 3, the liquid will accumulate there. When the liquid level in the downcomer plate 3 reaches the overflow hole 311 on the downcomer pipe 31, the liquid will flow from the overflow hole 311 into the downcomer pipe 31. The liquid flows into the upper tube sheet 2 through the downcomer 31 and accumulates on the upper tube sheet 2 to achieve a third reduction in speed. When the liquid level on the upper tube sheet 2 reaches the position of the tangential hole 222 of the film-forming tube 22, the liquid enters the film-forming tube 22 and flows downward along the inner wall of the film-forming tube 22 in a spiral flow manner, so that the liquid enters the heat exchange tube 21 in a spiral flow manner and maintains a spiral downward flow, thereby improving the film-forming effect of the liquid in the heat exchange tube 21. Since the liquid outlet end of the downcomer 31 is lower than the tangential hole 222 in the film-forming tube 22, the downcomer 31 will not cause disturbance to the liquid level when discharging the liquid, and the liquid can enter the film-forming tube 22 stably. If the two tangential holes 222 in the film-forming tube 22 cannot discharge the liquid into the heat exchanger 21 in time, the liquid level on the upper tube sheet 2 will be too high. The liquid can enter the film-forming tube 22 faster through the auxiliary flow hole 224.
[0023] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it. Although the utility model has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of this utility model. Any modifications or equivalent substitutions that do not depart from the spirit and scope of this utility model should be covered within the protection scope of the claims of this utility model.
Claims
1. A film-forming head in a falling film evaporator capable of stable film formation, including: The end cap is sealed to the upper tube sheet of the cylinder body. A plurality of heat exchange tubes are evenly distributed in the upper tube sheet. The feature is that a plurality of film-coated tubes are evenly distributed on the upper tube sheet and inserted into the heat exchange tubes. The outer wall of the film-coated tubes abuts against the inner wall of the heat exchange tubes. Two tangential holes tangential to the inner wall are symmetrically arranged on the wall of the film-coated tubes. The bottom of the film-coated tubes is configured as a funnel opening that gradually widens from top to bottom. The thickness between the inner and outer walls of the funnel opening gradually decreases from top to bottom. A downcomer is arranged above the film-coated tubes, and a plurality of downcomer tubes are sealed within the downcomer. The liquid pipe and the membrane pipe are offset. The outlet end of the downcomer extends downwards from the downcomer plate and is located below the tangential hole. An overflow hole is provided on the downcomer located in the downcomer plate. An overflow plate is provided above the downcomer plate. The outer diameter of the overflow plate is smaller than the inner diameter of the downcomer plate. Several distribution holes are evenly distributed on the bottom wall of the overflow plate. The distribution holes are offset from the downcomer. An inlet pipe is sealed on the end cap. The inlet end of the inlet pipe extends out of the end cap. The outlet end of the inlet pipe is sealed and welded to the bottom wall of the overflow plate and is offset from the distribution hole. An outlet hole is provided on the side wall of the inlet pipe.
2. The film-forming head in the falling film evaporator according to claim 1, characterized in that: Two liquid inlet pipes are symmetrically arranged on the end cap, and two liquid outlet holes are symmetrically arranged on the side wall of the liquid inlet pipes.
3. The film-forming head in the falling film evaporator according to claim 1, characterized in that: Several stiffening plates are evenly distributed around the outer wall of the overflow plate. The stiffening plates are welded to the inner wall of the end cap, and the overflow plate is aligned coaxially with the end cap.
4. The film-forming head in the falling film evaporator according to claim 1, characterized in that: Several threaded tie rods are welded around the circumference of the upper tube sheet. Several connecting holes are evenly distributed around the circumference of the bottom wall of the downcomer. Each threaded tie rod extends into the corresponding connecting hole. The threaded tie rod is fully welded to the connecting hole. A locking nut is threaded onto the threaded tie rod. The locking nut is screwed and abuts against the bottom inner wall of the downcomer. The downcomer and the overflow plate are aligned coaxially.
5. The film-forming head in the falling film evaporator according to claim 1, characterized in that: There are four overflow holes evenly distributed around the circumference of the downcomer.
6. The film-forming head in the falling film evaporator according to claim 1, characterized in that: Two auxiliary flow holes are symmetrically arranged on the wall of the membrane tube. The two auxiliary flow holes are higher than the bottom wall of the tangential holes, and the line connecting the two auxiliary flow holes is perpendicular to the line connecting the two tangential holes.
7. The film-forming head in the falling film evaporator according to claim 1, characterized in that: The connection structure between the upper tube sheet, heat exchange tubes, and membrane tubes is as follows: several inverted T-shaped holes are evenly distributed in the upper tube sheet. The heat exchange tubes are inserted into the large end of the inverted T-shaped holes and then welded to the upper tube sheet. The top of the heat exchange tubes abuts against the inner shoulder of the inverted T-shaped holes. An outer shoulder is provided on the outer wall of the membrane tubes. The membrane tubes are inserted into the heat exchange tubes after passing through the small end of the inverted T-shaped holes. The outer shoulder on the membrane tubes abuts against the upper tube sheet and is welded to the upper tube sheet.