A falling film evaporator for refrigeration

Abstract

The application belongs to the evaporator technical field, and particularly relates to a falling film evaporator for refrigeration, which comprises a cylinder body, a liquid refrigerant inlet and a gas refrigerant outlet are arranged at the top of the cylinder body, a distributor is arranged above the inside of the cylinder body, a first heat exchange pipe group is arranged below the distributor, a second heat exchange pipe group is arranged below the first heat exchange pipe group, the heat exchange pipe groups are rotationally installed on end covers, the same end of the first heat exchange pipe group and the second heat exchange pipe group is communicated, the free end of the first heat exchange pipe group is communicated with a heat source inlet, and the free end of the second heat exchange pipe group is communicated with a heat source outlet; a power assembly is transmissionally connected with the heat exchange pipe groups to generate disturbance to the falling film and increase the heat transfer area; the falling film is disturbed and cleaned by the rotation of the heat exchange pipes and the axial movement of the slip rings, the heat transfer performance is improved, and meanwhile, the center heat exchange pipe with the through slot structure is actively opened and avoided when the slip rings move, and the pipe body integrity is automatically restored after leaving to maintain the falling film function of the heat exchange pipe.

Description

Technical Field

[0001] This invention belongs to the field of evaporator technology, and specifically relates to a falling film evaporator for refrigeration. Background Technology

[0002] A falling film evaporator relies on gravity to evenly distribute liquid refrigerant to the top of the heat exchange tube bundle. The liquid refrigerant then flows downwards along the outer wall of the vertical or near-vertical heat exchange tubes under gravity, forming a thin liquid film covering the tube wall. Simultaneously, a refrigerant with a temperature higher than the refrigerant's boiling point (such as chilled water) flows inside the heat exchange tubes. Heat is transferred through the tube wall to the refrigerant liquid film outside the tubes. The refrigerant inside the liquid film absorbs heat and rapidly evaporates into gas. The resulting refrigerant vapor is usually drawn away by the suction port located above the evaporator or by the compressor. The advantage of this design is that it utilizes a thin liquid film to achieve extremely low thermal resistance and extremely high heat transfer efficiency between the refrigerant and the tube wall, significantly improving heat exchange performance. At the same time, since the refrigerant only covers the tube wall rather than immersing the entire tube bundle, it greatly reduces the amount of refrigerant required for the system.

[0003] Chinese patent document (publication number: CN103925749B) discloses a falling film evaporator, including a cylindrical body. An upper distributor is located at the top of the cylindrical body, with baffles on both sides of the top of the upper distributor. At least one baffle has serrated edges, forming an air passage with the inner wall of the cylindrical body. The air passage communicates with the gas refrigerant outlet. Baffles are located at the bottom of both sides of the upper distributor. Below the upper distributor is an upper heat exchange tube group, and below the upper heat exchange tube group are a lower heat exchange tube group and an oil-rich zone. The oil-rich zone is equipped with a level sensor for a chiller (heat pump) unit, and has an oil return port. This evaporator can switch between a full falling film heat exchange mode and a mixed falling film heat exchange mode under the control of a chiller (heat pump) unit, avoiding problems such as insufficient refrigerant dripping at the bottom or excessive refrigerant charge. It also prevents liquid carryover during air intake, improving the heat transfer coefficient and heat exchange efficiency.

[0004] When a falling film evaporator is in normal use, the refrigerant liquid film flows downward along the tube wall, mainly in a laminar flow state. This results in relatively high heat transfer resistance and a relatively low heat transfer coefficient. Furthermore, a stable temperature boundary layer is easily formed on the tube wall, which reduces heat exchange efficiency. In addition, dirt and deposits can easily accumulate on the tube wall during long-term operation, which may disrupt the formation of the falling film and reduce heat transfer performance. Moreover, heat-conducting tubes with through-grooves may have their outer wall integrity damaged, making it difficult to form a falling film and reducing overall heat exchange efficiency. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a falling film evaporator for refrigeration. Through the rotational design surrounding the heat exchange tubes and the reciprocating movement of the slip ring on the tubes, tangential disturbances are generated in the falling film outside the tubes, disrupting the static boundary layer and promoting liquid film renewal. This enhances the activity of the heat transfer boundary layer, increases the area of ​​falling film heat exchange, and cleans the heat exchange tubes. By coordinating the unfolding and pushing components and the opening and closing unit, the central heat exchange tube with a slotted structure actively opens to avoid the connecting rod when the slip ring moves. After the connecting rod leaves, it automatically merges back to restore the integrity of the tube body, preserving the falling film function of the central heat exchange tube with the slotted design and further improving the overall heat exchange efficiency.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A falling film evaporator for refrigeration includes a horizontally arranged cylindrical body with end caps at both ends. The top of the cylindrical body has a liquid refrigerant inlet and a gaseous refrigerant outlet. A distributor is located above the interior of the cylindrical body, with a first heat exchange tube group below the distributor and a second heat exchange tube group below the first heat exchange tube group. The heat exchange tube groups are rotatably mounted on the end caps. The first and second heat exchange tube groups are connected at the same end. The free end of the first heat exchange tube group is connected to a heat source inlet, and the free end of the second heat exchange tube group is connected to a heat source outlet. A power assembly is located at one end of the cylindrical body near the heat source inlet and outlet. The power assembly is connected to the heat exchange tube groups, causing disturbance to the falling film and increasing the heat transfer area.

[0008] Preferably, a first chamber and a second chamber are respectively provided at both ends of the cylinder. A layer plate is provided in the middle of the first chamber to form a heat source inlet chamber and a heat source outlet chamber distributed vertically. The heat source inlet chamber is provided with a heat source inlet, and the heat source outlet chamber is provided with a heat source outlet. A first heat exchange tube group connects the heat source inlet chamber and the second chamber, and a second heat exchange tube group connects the second chamber and the heat source outlet chamber. A transmission chamber is provided adjacent to the first chamber along the axial direction of the cylinder. The transmission chamber includes an intermediate plate and a bottom plate. The transmission chamber shares an intermediate plate with the first chamber. Multiple transmission gear sets are provided on the intermediate plate located in the transmission chamber.

[0009] Preferably, the first and second heat exchanger tube groups are symmetrically arranged. Each group of linkage tubes includes five rotatably arranged surrounding heat exchanger tubes and one fixed central heat exchanger tube, wherein the five surrounding heat exchanger tubes are arranged around the central heat exchanger tube. Gear sets are arranged corresponding to the linkage tubes, and each transmission gear set includes one central gear and five surrounding gears. The five surrounding heat exchanger tubes extend into the second chamber, and their other ends pass through the first chamber and enter the transmission chamber. Surrounding gears are respectively arranged at the ends of the surrounding heat exchanger tubes. Air holes are provided on the surrounding heat exchanger tubes located in the first chamber. A through groove is opened on the side wall of the central heat exchanger tube and fixed on the end cap. A conveying channel is integrally formed inside the tube body of the central heat exchanger tube. The conveying channel of the central heat exchanger tube connects the first chamber and the second chamber. A reciprocating screw is rotatably arranged inside the central heat exchanger tube. A scraper ring assembly is arranged on the reciprocating screw. The optical shaft part of one end of the reciprocating screw extends into the transmission chamber and is arranged with a central gear. The five surrounding gears mesh with the central gear respectively. The optical shaft part is connected to the power assembly.

[0010] Preferably, a second distribution box is provided between the first heat exchange tube group and the second heat exchange tube group, and the two heat exchange tube groups are symmetrically arranged with respect to the second distribution box; the heat exchange tubes are rotatably connected to the end caps and the intermediate plate through bearings; the optical shaft of the reciprocating screw is rotatably connected to the end caps and the intermediate plate through bearings.

[0011] Preferably, the scraper ring assembly includes a first slip ring and a nut mounted on a reciprocating screw. An annular gap is maintained between the inner wall of the central heat exchange tube and the outer wall of the reciprocating screw, with the nut located within the annular gap. The first slip ring is slidably fitted onto the outer circumference of the central heat exchange tube. A connecting rod is fixed between the nut and the first slip ring, and the connecting rod is slidably installed in a through groove on the central heat exchange tube. Five second slip rings are respectively fitted onto five surrounding heat exchange tubes adjacent to the central heat exchange tube, and all five second slip rings are fixedly connected to the outer wall of the first slip ring via connecting rods. When the reciprocating screw is driven to rotate, it drives the nut to move the slip rings at the corresponding heat exchange tubes, disturbing the falling film, increasing the heat transfer area, and cleaning the tube walls.

[0012] Preferably, the central heat exchange tube has an opening and closing unit inside the through groove. The opening and closing unit includes an isosceles trapezoidal column and an arc-shaped guide rod that are fixedly connected. Alternating clearance grooves are formed on the opposite inner walls of the central heat exchange tube through groove. An arc-shaped guide groove is formed within the circumferential direction of the clearance groove. The arc-shaped guide rod is slidably installed within the arc-shaped guide groove. The small end faces of two oppositely arranged isosceles trapezoidal columns in the same radial direction abut against each other. Arc-shaped plates are provided at the bottom of each isosceles trapezoidal column. The abutting arrangement of the two arc-shaped plates in the same radial direction fills the central heat exchange tube through groove, forming a complete outer circumference. An unfolding and pushing component is provided on the connecting rod. When the nut is driven, the unfolding and pushing component pushes the adjacent arc-shaped plates into the clearance grooves on both sides, forming clearance channels.

[0013] Preferably, the unfolding and pushing component includes a lifting plate and a side-pushing block, which are fixed to the connecting rod from top to bottom and maintain a vertical distance. The lifting plate and the side-pushing block are respectively formed on the connecting rod extending axially towards both sides along the central heat exchange tube, and the length of the lifting plate is greater than that of the side-pushing block. A wedge structure is provided on the side of the lifting plate near the arc-shaped plate, and an isosceles triangular prism is fixed on the side of the side-pushing block near the isosceles trapezoidal prism. The arc-shaped guide groove is deepened along the radial center direction to form a lifting and clearance groove, which increases the clearance space for the arc-shaped guide rod to move along the center direction. When the unfolding and pushing component is driven to move along the length of the groove, the lifting plate first lifts the arc-shaped plate to the height of the clearance groove. Then, the isosceles triangular prism of the side-pushing block abuts against the isosceles trapezoidal prisms on both sides and pushes the arc-shaped plate and the isosceles trapezoidal prism together into the clearance grooves on both sides to form a clearance channel.

[0014] Preferably, the power component includes a motor and a bidirectional gear ring. An annular groove is formed on the base plate on the side away from the transmission cavity, and the bidirectional gear ring, having an inner gear ring and an outer gear ring, slides inside the groove. A cover is provided on the base plate, with an annular limiting groove corresponding to the bidirectional gear ring. An outer flange is provided on the cover, and the outer flange is fixedly connected to the base plate. An opening is provided at the bottom of the cover, and a motor is located near the bottom of the cover. A drive gear is installed at the output end of the motor, and the drive gear meshes with the outer gear ring after passing through the opening. A transmission unit is provided on the base plate located inside the inner gear ring. The input end of the transmission unit meshes with the inner gear ring, and the output end of the transmission unit is transmitted to the optical shaft via a magnetic coupling element.

[0015] Preferably, the transmission unit includes a first clamping plate and a second clamping plate spaced apart. The first clamping plate and the second clamping plate are fixedly connected by multiple connecting columns. The connecting columns extend toward the base plate and are fixedly connected to the base plate, and a distance is maintained between the base plate and the second clamping plate. Blind slots are opened on one side of the base plate near several optical shafts. The optical shafts extend into the blind slots and are fixedly provided with second magnetic coupling elements at their ends. A transmission shaft is arranged coaxially with the second magnetic coupling elements on the other side of the base plate. The transmission shaft extends through the space between the two clamping plates. A sandwich gear is fixed on the transmission shaft located between the two clamping plates and near the internal gear ring. The sandwich gear and the internal gear ring are driven by meshing with a connecting gear. A sprocket is provided on the transmission shaft with the sandwich gear and the adjacent transmission shaft. The two sprockets are connected by a chain drive. The transmission shaft extends between the base plate and the second clamping plate and is provided with first magnetic coupling elements at its ends. The first magnetic coupling elements and the second magnetic coupling elements are connected by magnetic force for transmission.

[0016] Preferably, a baffle is provided inside the cylinder to facilitate gas-liquid separation, and a liquid refrigerant outlet is provided at the bottom of the cylinder; baffles are provided on both sides of the top of the distributor above, and the edges of the baffles are serrated. The serrations and the inner wall of the cylinder form an air passage, which is connected to the gas refrigerant outlet.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The present invention generates disturbance and cleaning effects on the falling film by the rotation design of the surrounding heat exchange tube and the axial movement design of the slip ring, thereby improving the heat transfer performance. At the same time, it also ensures that the central heat exchange tube with the through groove structure actively opens to avoid the slip ring when it moves, and automatically merges back to restore the integrity of the tube body after it leaves, thus preserving the falling film function of the heat exchange tube.

[0019] Specifically, the motor drives a bidirectional gear ring via a drive gear, which then transmits power to the optical shaft via a connecting gear, a sandwich gear, a transmission shaft, and a magnetic coupling component. The optical shaft drives a surrounding gear via a central gear, causing the surrounding heat exchange tube to rotate. This generates tangential disturbance to the falling film outside the tube, disrupting the static boundary layer. Simultaneously, the optical shaft drives a reciprocating screw to rotate, which in turn drives a slip ring via a nut to reciprocate on the central and surrounding heat exchange tubes. This generates longitudinal disturbance to the falling film and cleans the tube wall. When the slip ring moves to the slot position, the lifting plate lifts the arc-shaped plate via the inclined surface of the wedge structure, causing it to move radially with the arc-shaped guide rod and compress the second spring. Subsequently, the side pusher pushes the isosceles trapezoidal column into the clearance slot and compresses the first return spring, providing a travel channel for the connecting rod. After the slip ring leaves, the arc-shaped plate and the isosceles trapezoidal column are reset under the action of the first and second return springs, restoring the central heat exchange tube to a complete circumferential tube wall. This achieves the synergistic effect of rotational disturbance, axial cleaning, and intelligent clearance, significantly improving heat transfer efficiency and system reliability.

[0020] 2. In this invention, by designing the rotation around the heat exchange tube and the reciprocating movement of the slip ring on the heat exchange tube, tangential disturbance is generated to the falling film outside the tube, which destroys the static boundary layer and promotes liquid film renewal, enhances the activity of the heat transfer boundary layer, increases the area of ​​falling film heat exchange, and cleans the heat exchange tube.

[0021] Specifically, the motor drives a bidirectional gear ring to rotate via a drive gear. The bidirectional gear ring meshes with a connecting gear, causing the sandwich gear and the drive shaft to rotate together. The drive shaft with the sandwich gear is connected to an adjacent drive shaft via a sprocket and chain. The drive shaft located on one side of the base plate is connected to the optical shaft on the other side via a magnetic coupling device. The optical shaft is connected to several surrounding gears via a fixed central gear. The surrounding gears drive the fixed surrounding heat exchange tube to rotate. During the rotation of the surrounding heat exchange tube, the optical shaft drives the reciprocating screw to rotate together. The reciprocating screw drives the nut to reciprocate along the axis. The nut drives the slip ring to reciprocate on the corresponding central heat exchange tube and surrounding heat exchange tube. While cleaning the impurities attached to the tube wall, it generates longitudinal disturbance to the falling film, optimizes the liquid film distribution and flow state, generates tangential disturbance to the falling film outside the tube, destroys the static boundary layer and promotes liquid film renewal, increases the area of ​​falling film heat exchange, and improves the efficiency of heat exchange.

[0022] 3. In this invention, by cooperating with the unfolding and pushing components and the opening and closing unit, it is ensured that the central heat exchange tube with the through groove structure actively opens to avoid the connecting rod when the slip ring moves. After the connecting rod leaves, it automatically merges to restore the integrity of the tube body, thus preserving the falling film function of the central heat exchange tube with the through groove design and further improving the heat exchange efficiency of the overall structure.

[0023] Specifically, as the unfolding and pushing component slides inside the through groove of the central heat exchange tube along with the nut, the lifting plate first lifts the bottom of the arc-shaped plate through the inclined surface of the wedge structure, causing the arc-shaped plate and the arc-shaped guide rod to move together in the radial direction towards the center. The arc-shaped guide rod slides radially in the arc-shaped guide groove and compresses the second spring, moving the arc-shaped plate, which was originally flush with the outer wall of the central heat exchange tube, to above the bottom height of the clearance groove. Immediately afterwards, the isosceles triangular prism of the side push block contacts the two adjacent isosceles trapezoidal prisms and pushes them into the clearance grooves on both sides, providing a smooth passage for the connecting rod. At this time, the arc-shaped guide rod compresses the first and second return springs. After the connecting rod and the unfolding and pushing component leave, under the return force of the first return spring, the arc-shaped plates and isosceles trapezoidal prisms on both sides are pushed into the through groove. The return action of the second return spring pushes the arc-shaped plate to be flush with the outer wall of the central heat exchange tube, so that the central heat exchange tube with the through groove forms a complete circumferential tube wall, which is conducive to the formation of the falling film and enhances the heat transfer effect. Attached Figure Description

[0024] Figure 1 This is a three-dimensional schematic diagram of the overall installation structure of the present invention;

[0025] Figure 2 This is a three-dimensional schematic diagram of the clamping plate and gear ring in the engagement state of the present invention;

[0026] Figure 3 This is a three-dimensional schematic diagram of the disassembled transmission unit structure of the present invention. Figure 1 ;

[0027] Figure 4 This is a three-dimensional schematic diagram of the disassembled transmission unit structure of the present invention. Figure 2 ;

[0028] Figure 5 This is a three-dimensional schematic diagram of the transmission gear set mounting structure of the present invention;

[0029] Figure 6 This is a three-dimensional schematic diagram of the heat exchange tube and slip ring in the engagement state of the present invention;

[0030] Figure 7 This is a three-dimensional schematic diagram of the heat exchange tube and slip ring disassembled structure of the present invention;

[0031] Figure 8 This is a three-dimensional schematic diagram of the overall installation structure of the opening and closing unit of the present invention;

[0032] Figure 9 This is a three-dimensional schematic diagram of a partial structure of the opening and closing unit of the present invention. Figure 1 ;

[0033] Figure 10 This is a three-dimensional schematic diagram of a partial structure of the opening and closing unit of the present invention. Figure 2 ;

[0034] Figure 11 A three-dimensional schematic diagram of the engagement state of the unfolding and pushing component of the present invention squeezing out the arc-shaped plate;

[0035] Figure 12 This is a three-dimensional schematic diagram of the magnetic coupling structure between the drive shaft and the optical shaft of the present invention.

[0036] In the diagram: 11. Cylinder body; 12. End cap; 13. First heat exchange tube group; 14. Second heat exchange tube group; 15. Second distribution box; 16. Liquid refrigerant inlet; 17. Liquid refrigerant outlet; 18. First chamber; 19. Second chamber; 20. Heat source inlet; 21. Heat source outlet; 22. Partition plate; 23. Bottom plate; 24. Bidirectional gear ring; 25. Motor; 26. Sealing cap; 27. Optical shaft; 28. Central gear; 29. ​​Surrounding heat exchange tubes; 30. Surrounding gear; 31. Transmission gear set; 32. Internal gear ring; 33. External gear ring; 34. First clamping plate. Second clamping plate - 35; connecting column - 36; chain - 37; connecting gear - 38; central heat exchange tube - 39; first slip ring - 40; second slip ring - 41; connecting rod - 42; nut - 43; reciprocating screw - 44; arc plate - 45; lifting plate - 46; side push block - 47; isosceles trapezoidal column - 48; arc guide rod - 49; clearance groove - 50; arc guide groove - 51; first return spring - 52; drive shaft - 53; sandwich gear - 54; rotating bearing - 55; first magnetic coupling element - 56; second magnetic coupling element - 57; outer flange - 58. Detailed Implementation

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

[0038] Contents not described in detail in this specification are prior art known to those skilled in the art. In the description of this invention, it should be understood that terms such as "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, terms such as "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0039] Figures 1-12 As shown, a falling film evaporator for refrigeration includes a horizontally arranged cylindrical body 11, with end caps 12 at both ends. The top of the cylindrical body 11 has a liquid refrigerant inlet 16 and a gaseous refrigerant outlet. A distributor is located above the interior of the cylindrical body 11, with a first heat exchange tube group 13 below the distributor and a second heat exchange tube group 14 below the first heat exchange tube group 13. The heat exchange tube groups are rotatably mounted on the end caps 12. The first and second heat exchange tube groups 13 and 14 are connected at the same end. The free end of the first heat exchange tube group 13 is connected to a heat source inlet 20, and the free end of the second heat exchange tube group 14 is connected to a heat source outlet 21. A power assembly is located at one end of the cylindrical body near the heat source inlet / outlet. The power assembly is connected to the heat exchange tube groups, causing disturbance to the falling film and increasing the heat transfer area.

[0040] This invention improves heat transfer performance by disturbing and cleaning the falling film through the rotational movement of the heat exchange tube and the axial movement of the slip ring. At the same time, it also ensures that the central heat exchange tube with the through-groove structure actively opens to avoid the slip ring when it moves, and automatically merges back to restore the integrity of the tube body after it leaves, thus preserving the falling film function of the heat exchange tube.

[0041] Motor 25 drives bidirectional gear ring 24 via drive gear, which is then transmitted to optical shaft 27 via connecting gear 38, sandwich gear 54, drive shaft 53, and magnetic coupling component. Optical shaft 27 drives surrounding gear 30 via central gear 28, causing the surrounding heat exchange tube 29 to rotate, generating tangential disturbance to the falling film outside the tube and disrupting the static boundary layer. Simultaneously, optical shaft 27 drives reciprocating screw 44 to rotate, which drives slip ring to reciprocate on the central heat exchange tube 39 and surrounding heat exchange tube 29 via nut 43, generating longitudinal disturbance to the falling film and cleaning the tube wall. When the slip ring moves to the through slot position, lifting plate 46 passes through... The inclined surface of the wedge structure supports the arc plate 45, causing it to move radially with the arc guide rod 49 and compress the second spring. Subsequently, the side push block 47 pushes the isosceles trapezoidal column 48 into the clearance groove 50 and compresses the first return spring 52, providing a travel channel for the connecting rod 42. After the slip ring leaves, the arc plate 45 and the isosceles trapezoidal column 48 are reset under the action of the first return spring 52 and the second return spring, so that the central heat exchange tube 39 restores its complete circumferential tube wall, realizing the synergistic effect of rotational disturbance, axial cleaning and intelligent clearance, significantly improving heat transfer efficiency and system reliability. The following paragraphs will provide a detailed explanation.

[0042] Furthermore, a first chamber 18 and a second chamber 19 are respectively provided at both ends of the cylinder 11. A heat source inlet chamber and a heat source outlet chamber are formed by a layer plate in the middle of the first chamber 18. The heat source inlet chamber is provided with a heat source inlet 20, and the heat source outlet chamber is provided with a heat source outlet 21. The first heat exchange tube group 13 connects the heat source inlet chamber and the second chamber 19, and the second heat exchange tube group 14 connects the second chamber 19 and the heat source outlet chamber. A transmission chamber is provided adjacent to the first chamber 18 along the axial direction of the cylinder. The transmission chamber includes an intermediate plate 22 and a bottom plate 23. The transmission chamber and the first chamber 18 share the intermediate plate 22. Multiple transmission gear sets 31 are provided on the intermediate plate 22 located in the transmission chamber.

[0043] Furthermore, a second distribution box 15 is provided between the first heat exchange tube group 13 and the second heat exchange tube group 14. The two heat exchange tube groups are symmetrically arranged with respect to the second distribution box. Each group of linkage tubes includes 5 surrounding heat exchange tubes 29 and 1 central heat exchange tube 39, wherein the 5 surrounding heat exchange tubes 29 are arranged around the central heat exchange tube 39. The transmission gear set 31 includes 1 central gear 28 and 5 surrounding gears 30. The 5 surrounding heat exchange tubes 29 extend into the second chamber 19, and their other ends extend through the first chamber 18 and enter the transmission chamber. The ends of the surrounding heat exchange tubes 29 are respectively provided with surrounding gears 30. The surrounding heat exchange tubes 29 are rotatably connected to the end cap 12 and the intermediate plate 22 through bearings. The surrounding heat exchange tubes 29 located in the first chamber 18 are provided with air holes, and reinforcing rings are fixed at the air holes. A through groove is opened on the upper or lower top wall of the central heat exchange tube 39. The tube body of the central heat exchange tube 39 has an integrally formed conveying channel, which is located inside the tube wall of the central heat exchange tube 39. The two ends of the conveying channel pass through the ends of the central heat exchange tube 39. The conveying channel of the central heat exchange tube 39 connects the first chamber 18 and the second chamber 19 and is fixed on the end cover 12. A reciprocating screw 44 is installed inside the central heat exchange tube 39. A scraper ring assembly is installed on the reciprocating screw 44. The optical shaft part 27 at one end of the reciprocating screw 44 passes through the first chamber 18 and enters the transmission chamber, where a central gear 28 is installed. Five surrounding gears 30 mesh with the central gear 28 for transmission. The optical shaft part 27 adjacent to the central gear 28 is connected to the power assembly for transmission. The optical shaft part 27 of the reciprocating screw 44 is rotatably connected to the end cover 12 and the intermediate plate 22 through bearings.

[0044] Depending on the location of the linkage tubes, the through slot of the central heat exchange tube 39 can be set at the top or the bottom, which is conducive to the overall distribution of heat exchange tubes and promotes the falling film heat exchange.

[0045] In this invention, the rotating design of the heat exchange tube generates tangential disturbance to the falling film outside the tube, which destroys the static boundary layer and promotes liquid film renewal, enhances the activity of the heat transfer boundary layer, and increases the area of ​​falling film heat exchange.

[0046] The motor 25 drives the bidirectional gear ring 24 to rotate via the drive gear. The bidirectional gear ring 24 meshes with the connecting gear 38, which drives the sandwich gear 54 and the drive shaft 53 to rotate together. The drive shaft with the sandwich gear 54 is connected to the adjacent drive shaft via a sprocket and chain. The drive shaft 53 located on one side of the base plate 23 is connected to the optical shaft part 27 on the other side via a magnetic coupling component. The optical shaft part 27 meshes with several surrounding gears 30 via a fixed central gear 28. The surrounding gears 30 drive the fixed surrounding heat exchange tube 29 to rotate. During the rotation of the surrounding heat exchange tube 29, tangential disturbance is generated to the falling film outside the tube, which destroys the static boundary layer and promotes liquid film renewal, increases the area of ​​falling film heat exchange, and improves the efficiency of heat exchange.

[0047] Furthermore, the scraper assembly includes a first slip ring 40 and a nut 43 mounted on a reciprocating screw 44. An annular gap is maintained between the inner wall of the central heat exchange tube 39 and the outer wall of the reciprocating screw 44, and the nut 43 is located within this annular gap. The first slip ring 40 is slidably sleeved on the outer circumference of the central heat exchange tube 39. A connecting rod 42 is fixed between the nut 43 and the first slip ring 40, and the connecting rod 42 is slidably installed in a through groove on the central heat exchange tube 39. Five second slip rings 41 are respectively sleeved on the five surrounding heat exchange tubes 29 adjacent to the central heat exchange tube 39, and all five second slip rings 41 are fixedly connected to the outer wall of the first slip ring 40 via connecting rods. When the reciprocating screw 44 is driven to rotate, the nut 43 causes the slip rings to move at the corresponding heat exchange tubes, disturbing the falling film, increasing the heat transfer area, and cleaning impurities from the tube wall.

[0048] A guide groove can also be opened on the inner wall of the central heat exchange tube 39, and a protruding guide rod can be provided on the outer wall of the sliding nut 43. The guide rod slides in the guide groove to enhance the smooth sliding of the nut 43 and the stability of the overall structure.

[0049] In this invention, by cooperating with the unfolding and pushing components and the opening and closing unit, the central heat exchange tube with the through-groove structure is ensured to actively open and avoid the connecting rod 42 when the slip ring moves. After the connecting rod 42 leaves, it automatically merges to restore the integrity of the tube body, thus preserving the falling film function of the central heat exchange tube 39 with the through-groove design and further improving the heat exchange efficiency of the overall structure. The following paragraphs will provide a detailed description.

[0050] Furthermore, an opening and closing unit is provided inside the through groove of the central heat exchange tube 39. The opening and closing unit includes an isosceles trapezoidal column 48 and an arc-shaped guide rod 49 fixedly connected. Avoidance grooves 50 are respectively formed on the opposite inner walls of the through groove of the central heat exchange tube 39. An arc-shaped guide groove 51 is formed within the avoidance groove 50, deepening along the circumferential direction. The arc-shaped guide rod 49 is slidably installed within the arc-shaped guide groove 51. A first return spring 52 is installed between the bottom of the arc-shaped guide groove 51 and the arc-shaped guide rod 49. The arc-shaped guide groove 51 is close to the center of the central heat exchange tube 39. A second reset spring is provided between the inner wall of the line and the side of the adjacent arc-shaped guide rod 49; the small end faces of two isosceles trapezoidal columns 48 arranged in the same radial direction are abutted and installed, and the bottom of each isosceles trapezoidal column 48 is provided with an arc plate 45. The two arc plates 45 in the same radial direction are abutted and installed to fill the through groove of the central heat exchange tube 39 to form a complete outer circumference; an unfolding and pushing component is provided on the connecting rod 42. When the nut 43 is driven, the unfolding and pushing component drives the adjacent arc plate 45 to the avoidance grooves 50 on both sides to form an avoidance channel.

[0051] It should be noted that there is relative sliding between the second return spring and the arc-shaped guide rod 49. A sliding cover is sleeved on the end of the second return spring that contacts the arc-shaped guide rod 49, which facilitates the normal movement of the arc-shaped guide rod 49 and the normal compression and release of the second spring. The sliding cover can be a cylindrical sliding cover or a cuboid sliding cover. The cuboid sliding cover slides in contact with two opposite sides of the arc-shaped guide groove 51, ensuring that the second return spring pushes the arc-shaped plate 45 to be flush with the outer wall of the central heat exchange tube 39 under normal conditions, thereby achieving the reset function.

[0052] A sliding plate is fixed to the end of the first return spring 52. The two opposite sides of the sliding plate are slidably disposed inside the arc-shaped guide groove 51. The sliding plate is located between the first return spring 52 and the arc-shaped guide rod 49, which facilitates the normal functioning of the first return spring 52 while ensuring the smooth sliding between the sliding plate and the arc-shaped guide rod 49 and ensuring the stability of the structure.

[0053] It is worth noting that a limiting block is fixed on the side of the isosceles trapezoidal column 48 near the clearance groove 50. The limiting block can be a cuboid structure. Under normal installation conditions, the limiting blocks of adjacent isosceles trapezoidal columns 48 slide against each other. When the isosceles trapezoidal column 48 is pushed by the side push block 47, the adjacent limiting blocks can play an auxiliary support role to ensure the stability of the isosceles trapezoidal column 48 during movement.

[0054] Furthermore, the unfolding and pushing component includes a lifting plate 46 and a side-pushing block 47. The side-pushing block 47 and the lifting plate 46 are fixed to the connecting rod 42 from top to bottom and maintain a vertical distance. Both the lifting plate 46 and the side-pushing block 47 are self-symmetrical structures, extending axially along the central heat exchange tube 39 on the connecting rod 42 and towards both sides. The length of the lifting plate 46 is greater than that of the side-pushing block 47. A wedge structure is provided on the side of the lifting plate 46 near the arc-shaped plate 45, and the inclined surface of the wedge structure is slightly lower than that of the arc-shaped plate 45. An isosceles triangular prism is fixed on one side of the push block 47 near the isosceles trapezoidal column 48; the arc-shaped guide groove 51 is deepened along the radial center direction to open a lifting clearance groove, which increases the clearance space for the arc-shaped guide rod 49 to move along the center direction; when the unfolding push component is driven to move along the length of the through groove, the lifting plate 46 first lifts the arc plate 45 to the height of the clearance groove 50, and then the isosceles triangular prism of the side push block 47 abuts against the isosceles trapezoidal columns 48 on both sides, and pushes the arc plate 45 and the isosceles trapezoidal column 48 together into the clearance grooves 50 on both sides to form a clearance channel.

[0055] Specifically, the optical axis 27 drives the reciprocating screw 44 to rotate together. The reciprocating screw 44 drives the nut 43 to reciprocate along the axis. The nut drives the slip ring to reciprocate on the corresponding central heat exchange tube 39 and the surrounding heat exchange tube 29. While cleaning the impurities attached to the tube wall, it generates longitudinal disturbance to the falling film, optimizes the liquid film distribution and flow state, increases the heat exchange area, and improves working efficiency. When the pusher component slides inside the through groove of the central heat exchange tube 39 with the nut 43, the lifting plate 46 first lifts the bottom of the arc plate 45 through the inclined surface of the wedge structure, so that the arc plate 45 and the arc guide rod 49 move together in the direction towards the radial center. The arc guide rod 49 slides radially in the arc guide groove 51 and compresses the second spring, which originally moved away from the central heat exchange tube 39. The arc-shaped plate 45 with its outer wall flush with the ground moves to a height above the bottom of the clearance groove 50; immediately afterward, the isosceles triangular prism of the side push block 47 contacts the two adjacent isosceles trapezoidal prisms 48 and pushes them into the clearance grooves 50 on both sides, providing a smooth passage for the connecting rod 42; at this time, the arc-shaped guide rod 49 compresses the first return spring 52 and the second return spring. After the connecting rod 42 and the unfolding push component leave, under the reset force of the first return spring 52, the arc-shaped plates 45 and the isosceles trapezoidal prisms 48 on both sides are pushed into the through groove. The reset action of the second return spring pushes the arc-shaped plate 45 to a position flush with the outer wall of the central heat exchange tube 39, so that the central heat exchange tube 39 with the through groove forms a complete circumferential tube wall, which is conducive to the formation of the falling film and enhances the heat transfer effect.

[0056] Furthermore, the power assembly includes a motor 25 and a bidirectional gear ring 24. An annular groove is formed on the side of the base plate 23 away from the transmission cavity, and the bidirectional gear ring 24 is slidably disposed inside the annular groove. The bidirectional gear ring 24 has an inner gear ring 32 and an outer gear ring 33. A cover 26 is provided on the base plate 23, and an annular limiting groove is provided on the cover 26 corresponding to the bidirectional gear ring 24. An outer flange 58 is provided on the cover 26, and the outer flange 58 is fixedly connected to the base plate 23 by bolts. An opening is provided at the bottom of the cover 26, and a motor 25 is provided near the bottom of the cover 26. A drive gear is installed at the output end of the motor 25, and the drive gear meshes with the outer gear ring 33 after passing through the opening. A transmission unit is provided on the base plate 23 located inside the inner gear ring 32. The input end of the transmission unit meshes with the inner gear ring 32, and the output end of the transmission unit is transmitted to the optical shaft part 27 through a magnetic coupling component.

[0057] The bidirectional gear ring 24 extends axially to both sides to form connecting rings. The connecting ring on one side is installed in the ring groove, and the connecting ring on the other side is installed in the annular limiting groove on the cover 26 to form a stable transmission.

[0058] Furthermore, the transmission unit includes a first clamping plate 34 and a second clamping plate 35 spaced apart. The first clamping plate 34 and the second clamping plate 35 are fixedly connected by a plurality of connecting posts 36. The connecting posts 36 extend toward the base plate 23 and are fixedly connected to the base plate 23, and a distance is maintained between the base plate 23 and the second clamping plate 35. Blind slots are correspondingly formed on one side of the base plate 23 near several optical axis portions 27. The optical axis portions 27 extend into the blind slots and a second magnetic coupling member 57 is fixed at their ends. The optical axis portions 27 are connected to the base plate 23 by a rotating bearing 55. On the other side of the base plate 23, a second magnetic coupling member 57 is coaxially arranged. A drive shaft 53 extends through the space between two clamping plates and is connected to the clamping plates via bearings. A sandwich gear 54 is fixedly mounted on the drive shaft 53 located between the two clamping plates and near the internal gear ring 32. The sandwich gear 54 meshes with the internal gear ring 32 via a connecting gear 38. A sprocket is mounted on both the drive shaft with the sandwich gear 54 and the adjacent drive shaft, and the two sprockets are connected by a chain 37. The drive shaft 53 extends between the base plate 23 and the second clamping plate 35, and a first magnetic coupling element 56 is mounted at each end. The first magnetic coupling element 56 and the second magnetic coupling element 57 are connected by magnetic force for transmission.

[0059] Magnetic couplings achieve contactless torque transmission via magnetic fields. Their core consists of a driving rotor mounted at the input end and a driven rotor at the output end, physically separated by a non-magnetic insulating sleeve (such as Hastelloy or ceramic). When the driving rotor rotates, the high-intensity magnetic field generated by its permanent magnets (usually neodymium iron boron) or electromagnetic coils penetrates the insulating sleeve, driving the magnetic poles or conductor disks on the driven rotor to move synchronously. This design avoids mechanical contact and automatically disengages under torque overload to prevent mechanical damage.

[0060] Furthermore, a liquid refrigerant outlet 17 is provided at the bottom of the cylinder 11, and a baffle is provided inside the cylinder 11 to facilitate gas-liquid separation.

[0061] The top of the distributor is provided with baffles on both sides. The edges of the baffles are serrated. The serrations and the inner wall of the cylinder form an air passage. The air passage is connected to the gas refrigerant outlet.

[0062] It should be noted that the base plate 23 is made of non-magnetic material to avoid interference with the magnetic coupling components; the base plate 23 and the partition plate 22 are connected by a sealed connection at their axial outer edges.

[0063] The motor in this invention uses an external power supply and control system, which is existing technology and will not be described in detail here; the evaporator's channel ports are all connected to the corresponding medium input and output terminals, which are also existing technology and will not be described in detail here.

[0064] The present invention has been illustrated through the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that all related improvements to the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A falling film evaporator for refrigeration, comprising a horizontally arranged cylinder (11), both ends of the cylinder (11) being provided with end covers (12), and the top of the cylinder (11) being provided with a liquid refrigerant inlet (16) and a gaseous refrigerant outlet, characterized in that, The distributor is arranged on the top of the inner part of the cylinder (11), the first heat exchange pipe group (13) is arranged below the distributor, the second heat exchange pipe group (14) is arranged below the first heat exchange pipe group (13), the heat exchange pipe groups are rotatably arranged on the end cover (12), the same end of the first heat exchange pipe group (13) and the second heat exchange pipe group (14) is communicated, the free end of the first heat exchange pipe group (13) is communicated with the heat source inlet (20), the free end of the second heat exchange pipe group (14) is communicated with the heat source outlet (21); the power assembly is arranged on one end of the cylinder close to the heat source inlet and outlet, the power assembly is drivingly connected with the heat exchange pipe groups to generate disturbance to the falling film and increase the heat transfer area; the first chamber (18) and the second chamber (19) are arranged on the two ends of the cylinder (11) respectively, the middle part of the first chamber (18) is provided with a layer plate to form the heat source liquid inlet chamber and the heat source liquid outlet chamber which are distributed in upper and lower positions, the heat source liquid inlet chamber is provided with the heat source inlet (20), the heat source liquid outlet chamber is provided with the heat source outlet (21), the first heat exchange pipe group (13) is communicated with the heat source liquid inlet chamber and the second chamber (19), the second heat exchange pipe group (14) is communicated with the second chamber (19) and the heat source liquid outlet chamber; the transmission chamber is arranged along the axial direction of the cylinder close to the first chamber (18), the transmission chamber comprises the middle plate (22) and the bottom plate (23), the transmission chamber shares the middle plate (22) with the first chamber (18), a plurality of transmission gear sets (31) are arranged on the middle plate (22) in the transmission chamber; the first heat exchange pipe group (13) and the second heat exchange pipe group (14) are symmetrically arranged, each linkage pipe comprises five rotating surrounding heat exchange pipes (29) and one fixed central heat exchange pipe (39), wherein the five rotating surrounding heat exchange pipes (29) are arranged outside the central heat exchange pipe (39); the gear sets (31) are arranged corresponding to the linkage pipes, each transmission gear set (31) comprises one central gear (28) and five surrounding gears (30); the five rotating surrounding heat exchange pipes (29) extend into the second chamber (19), the other ends of the five rotating surrounding heat exchange pipes (29) all penetrate through the first chamber (18) to enter the transmission chamber, the end parts of the rotating surrounding heat exchange pipes (29) are respectively provided with the surrounding gears (30); the rotating surrounding heat exchange pipes (29) in the first chamber (18) are all provided with air holes; the side wall of the central heat exchange pipe (39) is provided with a through groove and is fixed on the end cover (12), the inner part of the pipe body of the central heat exchange pipe (39) is integrally formed with a conveying channel; the conveying channel of the central heat exchange pipe (39) is communicated with the first chamber (18) and the second chamber (19); the reciprocating screw rod (44) is rotatably arranged in the central heat exchange pipe (39), the reciprocating screw rod (44) is provided with a scraping ring assembly, the optical shaft part (27) of one end of the reciprocating screw rod (44) extends into the transmission chamber to be provided with the central gear (28), the five surrounding gears (30) are respectively engaged with the central gear (28); the optical shaft part (27) is drivingly connected with the power assembly; the scraping ring assembly comprises the first sliding ring (40) and the nut (43) mounted on the reciprocating screw rod (44), the inner wall of the central heat exchange pipe (39) and the outer wall of the reciprocating screw rod (44) keep an annular space, and the nut (43) is located in the annular space.The first sliding ring (40) is sleeved on the outer periphery of the central heat exchange pipe (39), the nut (43) is fixed with the first sliding ring (40), and the connecting rod (42) is slidingly installed in the through groove on the central heat exchange pipe (39).

2. Falling film evaporator for refrigeration according to claim 1, characterized in that The second distribution box (15) is arranged between the first heat exchange pipe group (13) and the second heat exchange pipe group (14), and the two heat exchange pipe groups are symmetrically arranged relative to the second distribution box; the surrounding heat exchange pipe (29) is rotatably connected between the end cover (12) and the intermediate plate (22) through a bearing; and the optical axis part (27) of the reciprocating lead screw (44) is rotatably connected between the end cover (12) and the intermediate plate (22) through a bearing.

3. The falling film evaporator for refrigeration according to claim 1, characterized in that, The second sliding ring (41) is arranged on the five surrounding heat exchange pipes (29) adjacent to the central heat exchange pipe (39), the five second sliding rings (41) are fixedly connected with the outer wall of the first sliding ring (40) through a connecting rod; when the reciprocating lead screw (44) is driven to rotate, the nut (43) drives the sliding ring to move at the corresponding heat exchange pipe to generate disturbance to the falling film, increase the heat transfer area and clean the pipe wall.

4. The falling film evaporator for refrigeration according to claim 3, characterized in that, The through slot of the central heat exchange pipe (39) is provided with an opening and closing unit, the opening and closing unit comprises isosceles trapezoidal columns (48) and arc-shaped guide rods (49) fixedly connected, the opposite inner walls of the through slot of the central heat exchange pipe (39) are respectively provided with avoiding grooves (50), the avoiding grooves (50) are provided with arc-shaped guide grooves (51) in the circumferential direction, and the arc-shaped guide rods (49) are slidably installed in the arc-shaped guide grooves (51); the small end faces of the two isosceles trapezoidal columns (48) of the same diameter are arranged in opposite directions and abut against each other, the bottoms of the isosceles trapezoidal columns (48) are provided with arc-shaped plates (45), and the two arc-shaped plates (45) of the same diameter are arranged in abutment to fill the through slot of the central heat exchange pipe (39) and form a complete outer circumference; the link rod (42) is provided with an unfolding and pushing part, when the nut (43) is driven, the unfolding and pushing part drives the arc-shaped plate (45) adjacent to the arc-shaped plate (45) to move to the avoiding grooves (50) on both sides to form an avoiding channel.

5. Falling film evaporator for refrigeration according to claim 4, characterized in that The unfolding and pushing part comprises a lifting plate (46) and a side pushing block (47), the side pushing block (47) and the lifting plate (46) are fixed on the link rod (42) from top to bottom and maintain a distance therebetween; the lifting plate (46) and the side pushing block (47) extend in the axial direction of the central heat exchange pipe (39) on the link rod (42) to form two sides, and the length of the lifting plate (46) is greater than that of the side pushing block (47); a wedge structure is arranged on one side of the lifting plate (46) close to the arc-shaped plate (45), an isosceles triangular column is fixed on one side of the side pushing block (47) close to the isosceles trapezoidal column (48); the arc-shaped guide groove (51) is provided with a lifting avoiding groove in the radial direction of the center, so that the arc-shaped guide rod (49) moves in the radial direction of the center to increase the avoiding space; when the unfolding and pushing part is driven to move in the length direction of the through slot, the lifting plate (46) first lifts the arc-shaped plate (45) to the height of the avoiding groove (50), then the isosceles triangular column of the side pushing block (47) abuts against the isosceles trapezoidal columns (48) on both sides, and the arc-shaped plate (45) and the isosceles trapezoidal column (48) are pushed into the avoiding grooves (50) on both sides to form an avoiding channel.

6. The falling film evaporator for refrigeration according to claim 1, characterized in that, The motor (25) and the bidirectional gear ring (24) of the power assembly, a ring groove is formed on the side of the bottom plate (23) away from the transmission cavity, the bidirectional gear ring (24) is slidably arranged in the ring groove, and the bidirectional gear ring (24) has an inner gear ring (32) and an outer gear ring (33); a cover (26) is arranged on the bottom plate (23), an annular limiting groove is arranged on the cover (26) corresponding to the bidirectional gear ring (24), an outer flange (58) is arranged on the cover (26), and the outer flange (58) is fixedly connected to the bottom plate (23); an opening is arranged at the bottom of the cover (26), a motor (25) is arranged near the bottom of the cover (26), an output end of the motor (25) is provided with a driving gear, and the driving gear is engaged with the outer gear ring (33) after passing through the opening; a transmission unit is arranged on the bottom plate (23) in the inner gear ring (32), an input end of the transmission unit is engaged with the inner gear ring (32), and an output end of the transmission unit is transmitted to the optical shaft part (27) through a magnetic coupling.

7. Falling film evaporator for refrigeration according to claim 6, characterized in that The transmission unit comprises a first clamping plate (34) and a second clamping plate (35) arranged at intervals, the first clamping plate (34) and the second clamping plate (35) are fixedly connected through a plurality of connecting columns (36), the connecting columns (36) extend towards the bottom plate (23) and are fixedly connected to the bottom plate (23), and a distance is maintained between the bottom plate (23) and the second clamping plate (35); a blind groove is formed on one side of the bottom plate (23) near the plurality of optical shaft parts (27), the optical shaft part (27) extends into the blind groove and is fixedly provided with a second magnetic coupling (57) at the end portion; a transmission shaft (53) is coaxially arranged on the other side of the bottom plate (23) corresponding to the second magnetic coupling (57), the transmission shaft (53) extends through to between the two clamping plates, the transmission shaft (53) between the two clamping plates and close to the inner gear ring (32) is respectively fixedly provided with a clamping gear (54), and the clamping gear (54) and the inner gear ring (32) are engaged and transmitted through a connecting gear (38); a sprocket is arranged on the transmission shaft on which the clamping gear (54) is arranged and the adjacent transmission shaft; the two sprockets are transmissionally connected through a chain (37); the transmission shaft (53) extends to between the bottom plate (23) and the second clamping plate (35) and is respectively provided with a first magnetic coupling (56) at the end portion, and the first magnetic coupling (56) and the second magnetic coupling (57) are transmissionally connected through magnetic force.

8. The falling film evaporator for refrigeration according to claim 2, characterized in that, A spoiler is arranged in the cylinder (11), which is beneficial to gas-liquid separation, and a liquid refrigerant outlet (17) is arranged at the bottom of the cylinder (11); The upper distributor is provided with air baffles on both sides of the top, the edges of the air baffles are provided with sawteeth, the sawteeth and the inner wall of the cylinder form a gas passage, and the gas passage is communicated with the gas refrigerant outlet.

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