A vertically movable telescopic air supply pipe with adjustable guide and composite seal

Abstract

The application discloses a vertical movable telescopic air supply pipe with adjustable guide and composite seal and relates to the technical field of industrial ventilation and air conditioning technology, which comprises a rack assembly, a fixed air supply and return pipe line, a vertical nested circular air pipe body, an upper and lower layered pulley guide mechanism, a plate type labyrinth lip composite seal mechanism, a double-wire rod synchronous reciprocating lifting mechanism and a horizontal air blowing branch pipe assembly. The rack assembly is a profile steel welded rectangular bearing rack, the double-wire rod synchronous reciprocating lifting mechanism is fixed on the top beam of the rack assembly, two limiting guide rails are symmetrically and vertically fixed on the inner side of the rack assembly, and limiting switches are fixedly installed on the upper and lower ends of the limiting guide rails. The fixed air supply and return pipe line is connected with an air supply cabinet. The application can effectively solve the problems of airflow blind area and uneven material process quality between layers in the conventional fixed air pipe air supply, and the equipment is stable in operation, long in service life and suitable for long-time continuous air supply operation of various clean food processing workshops.

Description

Technical Field

[0001] This invention relates to the field of industrial ventilation and air conditioning technology, and in particular to a vertically movable telescopic air supply duct with adjustable guidance and composite sealing. Background Technology

[0002] In industrial production scenarios such as meat product air-drying and fermentation, fresh food thawing, agricultural and sideline product storage and air-drying, and clean food processing, raw materials and semi-finished products are usually stacked in layers inside multi-layer material racks. Food fermentation, dehydration, and maturation processes have strict requirements for the uniformity of the flow field in the workshop: the wind speed and temperature in different layer height areas within the space must be kept uniform to ensure that the dehydration rate and fermentation degree of each layer of material are synchronized, and to avoid quality defects such as local over-drying, insufficient surface fermentation, product color difference, and uneven flavor.

[0003] Currently, the mainstream ventilation and air supply solutions in the industry all adopt a fixed duct air distribution structure. The air outlet of the duct is installed at a fixed height, and the air jet can only cover a single horizontal height range. This cannot meet the full coverage air supply requirements of multi-layered carts with upper, middle, and lower layers of materials. Large areas of airflow stagnation blind spots are formed in the upper, middle, and lower layers of the cart. Due to the uneven airflow distribution, the temperature difference between the materials in the layers can generally reach 3℃ to 8℃. The dehydration and fermentation processes are significantly different, and the physical and chemical indicators and appearance quality of the finished products in the same batch are inconsistent, resulting in a high defect rate. This seriously restricts the standardized production of large-scale food processing production lines.

[0004] In summary, the industry urgently needs a vertically movable telescopic air supply duct that can dynamically sweep air throughout the entire area, has adjustable coaxial guidance, and a composite low-leakage seal to meet the production needs of food processing workshops for uniform air supply, long-life stable operation, and clean and pollution-free production. Summary of the Invention

[0005] This invention discloses a vertically movable telescopic air supply pipe with adjustable guidance and composite sealing. It drives the horizontal air spray branch pipe to sweep back and forth throughout the entire stroke through the lifting inner pipe. The airflow from the spray hole covers the entire material layer height of the upper, middle and lower parts of the frame, effectively eliminating the airflow blind zone caused by fixed air supply. The temperature difference between multiple material layers is stably controlled within a small range, and the consistency of dehydration and drying processes is greatly improved.

[0006] It can achieve coaxial operation of the pipe body without jamming and has a long service life: the double-layer pulley guide structure restricts the radial displacement of the pipe body in sections, and the lower pulley group accurately corrects the coaxiality through spring adjusting nuts to adapt to processing and assembly errors; the vertical load is completely borne by the lead screw, and the guide pulley only performs radial limit, with rolling friction throughout the process, avoiding eccentric jamming and pipe wall scraping and wear faults.

[0007] The composite seal balances low friction and low leakage, making it suitable for food production conditions: the multi-layer plate labyrinth uses a non-contact seal to complete the main throttling seal, eliminating rubber friction loss and preventing debris from contaminating the meat processing environment; the downstream lip seal only blocks a small amount of residual air leakage, significantly reducing overall frictional resistance compared to traditional all-rubber seals, and also significantly reducing the air leakage rate compared to traditional seals. It also results in low air volume loss under high-pressure air supply conditions. In summary, it solves the problems in the background technology.

[0008] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:

[0009] The present invention provides a vertically movable telescopic air supply duct with adjustable guidance and composite sealing, comprising a frame assembly, a fixed supply and return air duct, a vertically nested circular air duct body, an upper and lower layered pulley guide mechanism, a plate-type labyrinth lip-shaped composite sealing mechanism, a double screw synchronous reciprocating lifting mechanism, and a horizontal air jet branch duct assembly.

[0010] The frame assembly is a rectangular load-bearing frame welded from steel sections. The top crossbeam of the frame assembly is fixed with a double screw synchronous reciprocating lifting mechanism. Two limit guide rails are symmetrically and vertically fixed inside the frame assembly. Limit switches are fixedly installed at the upper and lower ends of the limit guide rails respectively. One end of the fixed supply and return air duct is connected to the air supply fan, and the other end of the fixed supply and return air duct is flange-sealed and connected to the vertical nested circular air duct body.

[0011] The vertical nested circular duct body is installed inside the frame assembly. The outer wall of the vertical nested circular duct body is equipped with an upper and lower layered pulley guide mechanism and a plate-type labyrinth lip-shaped composite sealing mechanism. The lower end of the vertical nested circular duct body is fixedly connected to the horizontal air jet branch assembly. The horizontal air jet branch assembly is slidably connected to two limit guide rails. The output end of the double screw synchronous reciprocating lifting mechanism is rigidly connected to the horizontal air jet branch assembly. The double screw synchronous reciprocating lifting mechanism and the limit switch are electrically connected to an external PLC programmable controller.

[0012] Furthermore, the vertical nested circular duct body includes a fixed outer duct and a lifting inner duct; the fixed outer duct is rigidly fixed to the top crossbeam of the frame assembly, and the lifting inner duct is coaxially nested inside the fixed outer duct. The lower end of the lifting inner duct is rigidly connected to the horizontal air jet branch duct assembly; the horizontal air jet branch duct assembly includes an outer frame and multiple horizontal branch ducts symmetrically arranged at the lower end of the lifting inner duct. The walls of the horizontal branch ducts are evenly provided with lateral spray holes along their length, and the lower end of the lifting inner duct and the horizontal branch ducts are both located inside the outer frame and are connected and fixed by multiple clamps. The two sides of the outer frame are slidably connected to two limiting guide rails respectively.

[0013] Furthermore, the upper and lower layered pulley guide mechanism includes an upper inner tube fixed pulley group and a lower outer tube spring adjustable pulley group; the upper inner tube fixed pulley group has four pulley brackets evenly arranged at 90° along the outer wall of the top of the lifting inner tube, and the pulley brackets are equipped with wear-resistant pulleys, the outer edge of the wear-resistant pulleys is attached to the inner wall of the fixed outer tube.

[0014] Furthermore, the adjustable pulley assembly of the lower outer tube spring is evenly arranged with four sets of adjustment components at 90° along the outer wall of the lower end of the fixed outer tube. Each set of adjustment components includes a mounting bracket, a pulley body, a compression spring, a locking bolt, and an adjusting nut. The mounting bracket is evenly installed around the outer wall of the lower end of the fixed outer tube. A locking bolt is movably inserted through the mounting bracket. One end of the locking bolt is fixedly connected to a movable pulley frame. The pulley body is assembled inside the movable pulley frame. The adjusting nut is screwed to the locking bolt. One side of the adjusting nut abuts against the outer wall of the mounting bracket. The compression spring is sleeved on the outside of the locking bolt. Both ends of the compression spring are fixedly connected to the movable pulley frame and the mounting bracket, respectively.

[0015] Furthermore, the plate-type labyrinth lip-shaped composite sealing mechanism is located in the annular mating area between the outer wall of the upper section of the lifting inner tube and the inner wall of the fixed outer tube. The plate-type labyrinth lip-shaped composite sealing mechanism includes a multi-layer plate-type straight-through labyrinth throttling section and a food-grade EPDM oblique lip sealing section arranged sequentially along the airflow direction.

[0016] Furthermore, the multi-layer plate-type straight-through labyrinth throttling section is composed of multiple parallel annular baffles, with the number of annular baffles being 3-5. The annular baffles are horizontally welded to the outer wall of the lifting inner tube, and a 3-5mm annular gap is reserved between the annular baffles and the inner wall of the fixed outer tube.

[0017] Furthermore, the food-grade EPDM oblique lip sealing section is provided with an annular groove plate, which is fixedly welded to the outer wall of the lifting inner tube. An outer oblique lip sealing ring is provided inside the groove of the annular groove plate. The outer oblique lip sealing ring is fixed by segmented stainless steel pressure strips and bolts. The outer oblique lip sealing ring is attached to the inner wall of the outer tube with its lip facing outward and downward.

[0018] Furthermore, the dual-screw synchronous reciprocating lifting mechanism includes a stepper motor, a bevel gear commutator, a universal drive shaft, and two sets of RXP screw lifting modules; the output end of the stepper motor is connected to the bevel gear commutator, and the two sides of the bevel gear commutator are respectively connected to the universal drive shaft. Each of the two universal drive shafts is equipped with a set of RXP screw lifting modules, and the RXP screw lifting modules are fixedly installed at the frame assembly.

[0019] Furthermore, the lower flanges of both sets of RXP screw lifting modules are rigidly connected to the horizontal air jet branch pipe assembly; the stepper motor and limit switch are electrically connected to an external PLC programmable controller.

[0020] Furthermore, an annular limiting ring is provided on the inner wall of the lower end of the fixed outer tube. The limiting ring is located below the annular groove plate, and the inner ring size of the limiting ring is smaller than the outer ring size of the annular groove plate. The inner ring of the limiting ring does not contact the outer wall of the lifting inner tube.

[0021] The present invention has the following advantages over the prior art:

[0022] (1) This technical solution can achieve dynamic uniform air supply throughout the entire area and controllable temperature difference between layers: the lifting inner pipe drives the horizontal spray branch pipe to sweep back and forth throughout the entire stroke, and the airflow of the spray hole covers the entire material layer height of the upper, middle and lower parts of the frame, effectively eliminating the airflow blind zone caused by fixed air supply, and the temperature difference between multiple material layers is stably controlled within a small range, greatly improving the consistency of dehydration and drying processes.

[0023] (2) This technical solution can realize the pipe body telescopic and coaxial operation without jamming, and the equipment has a long service life: the double-layer pulley guide structure restricts the radial offset of the pipe body in sections, and the lower pulley group accurately corrects the coaxiality through the spring adjusting nut to adapt to the processing and assembly error; the vertical load is completely borne by the screw, and the guide pulley only performs radial limit, with rolling friction throughout the process, avoiding eccentric jamming and pipe wall scraping and wear faults;

[0024] (3) The composite seal of this technical solution takes into account both low friction and low leakage, and is suitable for food production conditions: the multi-layer plate labyrinth uses non-contact sealing to complete the main throttling seal, without rubber friction loss, and will not generate debris to contaminate the meat processing environment; the downstream lip seal only blocks a small amount of residual air leakage, the overall friction resistance is significantly reduced compared with the traditional all-rubber seal, the air leakage rate is also significantly reduced compared with the traditional seal, and the air volume loss is small under high pressure air supply conditions. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the present invention;

[0027] Figure 2 This is a schematic diagram of the structure of the present invention from another perspective;

[0028] Figure 3This is a schematic diagram of the internal cross-sectional structure of the frame assembly of the present invention;

[0029] Figure 4 This is a schematic diagram of the stepper motor drive connection structure of the present invention;

[0030] Figure 5 This is a schematic diagram of the limiting guide rail installation structure of the present invention;

[0031] Figure 6 This is a schematic diagram of the horizontal branch pipe installation structure of the present invention;

[0032] Figure 7 This is a schematic diagram of the exploded structure of the pulley body of the present invention.

[0033] Figure 8 This is a schematic diagram of the cross-sectional structure of the external oblique lip sealing ring of the present invention.

[0034] In the diagram: 1. Frame assembly; 2. Fixed supply and return air ducts; 3. Limiting ring; 4. Vertical nested circular duct body; 401. Fixed outer duct; 402. Lifting inner duct; 5. Upper and lower layered pulley guide mechanism; 501. Pulley bracket; 502. Wear-resistant pulley; 503. Mounting bracket; 504. Pulley body; 505. Compression spring; 506. Locking bolt; 507. Adjusting nut; 508. Movable pulley bracket; 6. Horizontal jet branch duct assembly; 601. External frame; 602. Horizontal branch duct; 603. Clamp; 7. Double screw synchronous reciprocating lifting mechanism; 701. Stepper motor; 702. Bevel gear commutator; 703. Universal drive shaft; 704. RXP 8. Screw lifting module; 9. Limit guide rail; 10. Limit switch; 11. Air supply unit; 12. Annular partition; 13. Annular groove plate; 14. External oblique lip sealing ring. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] In the description of this invention, it should be understood that the terms "surface", "side", "gap", "peripheral", etc., which indicate orientation or positional relationship, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this invention.

[0037] Reference Figures 1-8A vertically movable telescopic air supply duct with adjustable guidance and composite sealing includes a frame assembly 1, a fixed supply and return air duct 2, a vertical nested circular air duct body 4, an upper and lower layered pulley guide mechanism 5, a plate-type labyrinth lip-shaped composite sealing mechanism, a double screw synchronous reciprocating lifting mechanism 7, and a horizontal air jet branch duct assembly 6.

[0038] The frame assembly 1 is a rectangular load-bearing frame welded from steel. The top crossbeam of the frame assembly 1 is fixed with a double screw synchronous reciprocating lifting mechanism 7. Two limit guide rails 8 are symmetrically and vertically fixed inside the frame assembly 1. Limit switches 9 are fixedly installed at the upper and lower ends of the limit guide rails 8 respectively. One end of the fixed supply and return air duct 2 is connected to the air supply fan 10, and the other end of the fixed supply and return air duct 2 is flange-sealed and connected to the vertically nested round air duct body 4.

[0039] The vertical nested circular duct body 4 is installed inside the frame assembly 1. The outer wall of the vertical nested circular duct body 4 is equipped with an upper and lower layered pulley guide mechanism 5 and a plate-type labyrinth lip-shaped composite sealing mechanism. The lower end of the vertical nested circular duct body 4 is fixedly connected to the horizontal air jet branch pipe assembly 6. The horizontal air jet branch pipe assembly 6 is slidably connected to two limit guide rails 8. The output end of the double screw synchronous reciprocating lifting mechanism 7 is rigidly connected to the horizontal air jet branch pipe assembly 6. The double screw synchronous reciprocating lifting mechanism 7 and the limit switch 9 are electrically connected to an external PLC programmable controller.

[0040] The vertical nested circular duct body 4 includes a fixed outer duct 401 and a lifting inner duct 402. The fixed outer duct 401 is rigidly fixed to the top crossbeam of the frame assembly 1. The lifting inner duct 402 is coaxially nested inside the fixed outer duct 401. The lower end of the lifting inner duct 402 is rigidly connected to the horizontal air jet branch duct assembly 6. The horizontal air jet branch duct assembly 6 includes an outer frame 601 and multiple horizontal branch ducts 602 symmetrically arranged at the lower end of the lifting inner duct 402. The pipe wall of the horizontal branch duct 602 is evenly provided with lateral spray holes along the length direction. The lower end of the lifting inner duct 402 and the horizontal branch duct 602 are both located inside the outer frame 601 and are connected and fixed by multiple clamps 603. The two sides of the outer frame 601 are slidably connected to two limiting guide rails 8 respectively.

[0041] The upper and lower layered pulley guide mechanism 5 includes an upper inner tube fixed pulley group and a lower outer tube spring-adjustable pulley group. The upper inner tube fixed pulley group has four pulley brackets 501 evenly arranged at 90° along the outer wall of the top of the lifting inner tube 402. Each pulley bracket 501 is equipped with a wear-resistant pulley 502, the outer edge of which is fitted against the inner wall of the fixed outer tube 401. The lower outer tube spring-adjustable pulley group has four adjusting components evenly arranged at 90° along the lower outer wall of the fixed outer tube 401. Each adjusting component includes a mounting bracket 503, a pulley body 504, a compression spring 505, a locking bolt 506, and an adjusting nut. 507; Mounting brackets 503 are evenly installed around the lower outer wall of the fixed outer tube 401. A locking bolt 506 is movably inserted through the mounting bracket 503. One end of the locking bolt 506 is fixedly connected to a movable pulley frame 508. The movable pulley frame 508 is equipped with a pulley body 504. An adjusting nut 507 is screwed to the locking bolt 506. One side of the adjusting nut 507 abuts against the outer wall of the mounting bracket 503. A compression spring 505 is sleeved on the outside of the locking bolt 506. The two ends of the compression spring 505 are fixedly connected to the movable pulley frame 508 and the mounting bracket 503, respectively.

[0042] The plate-type labyrinth lip-shaped composite sealing mechanism is located in the annular mating area between the outer wall of the upper section of the lifting inner tube 402 and the inner wall of the fixed outer tube 401. The plate-type labyrinth lip-shaped composite sealing mechanism includes a multi-layer plate-type straight-through labyrinth throttling section and a food-grade EPDM oblique lip sealing section arranged sequentially along the airflow direction. The multi-layer plate-type straight-through labyrinth throttling section is composed of multiple parallel annular baffles 11, with 3-5 annular baffles 11. The annular baffles 11 are horizontally welded to the outer wall of the lifting inner tube 402, and a 3-5mm annular gap is reserved between the annular baffles 11 and the inner wall of the fixed outer tube 401. An annular groove plate 12 is provided at the food-grade EPDM oblique lip sealing section. The annular groove plate 12 is fixedly welded to the outer wall of the lifting inner tube 402. An outer oblique lip sealing ring 13 is provided inside the groove of the annular groove plate 12. The outer oblique lip sealing ring 13 is fixed by segmented stainless steel pressure strips and bolts. The lip of the outer oblique lip sealing ring 13 faces outward and downward and fits against the inner wall of the fixed outer tube 401.

[0043] The dual-screw synchronous reciprocating lifting mechanism 7 includes a stepper motor 701, a bevel gear commutator 702, a universal drive shaft 703, and two sets of RXP screw lifting modules 704. The output end of the stepper motor 701 is connected to the bevel gear commutator 702, and the two sides of the bevel gear commutator 702 are respectively connected to the universal drive shaft 703. Each end of the two universal drive shafts 703 is equipped with a set of RXP screw lifting modules 704, and the RXP screw lifting modules 704 are fixedly installed at the frame assembly 1. The lower flanges of the two sets of RXP screw lifting modules 704 are rigidly connected to the horizontal air jet branch pipe assembly 6. The stepper motor 701 and the limit switch 9 are electrically connected to an external PLC programmable controller.

[0044] An annular retaining ring 3 is provided on the inner wall of the lower end of the fixed outer tube 401. The retaining ring 3 is located below the annular groove plate 12, and the inner ring size of the retaining ring 3 is smaller than the outer ring size of the annular groove plate 12. The inner ring of the retaining ring 3 does not contact the outer wall of the lifting inner tube 402.

[0045] During the specific implementation process, when the equipment is running, the air supply fan 10 continuously outputs constant temperature and pressure process airflow. The airflow is delivered to the inside of the fixed outer pipe 401 through the fixed supply and return air duct 2. After the airflow enters the annular cooperation area of ​​the inner and outer pipes, it first flows through the multi-layer plate-type straight-through labyrinth throttling section. The airflow repeatedly contracts, expands, and turns in the return channel formed by the multi-layer annular partition 11, and the air pressure is continuously dissipated. Most of the airflow flows smoothly into the lifting inner pipe 402. A small amount of airflow that penetrates the labyrinth gap will be blocked by the downstream food-grade EPDM outer oblique lip sealing ring 13, thereby reducing the overall air leakage loss. After the airflow enters the lifting inner pipe 402, it is diverted to multiple horizontal branch pipes 602 at the bottom. The side nozzles on the side walls of the branch pipes send out uniform airflow laterally, which moves up and down synchronously with the lifting inner pipe 402, continuously covering the entire height range of the multi-layer material rack.

[0046] The operator pre-sets operating parameters such as lifting speed, reciprocating stroke, and cycle time in the external PLC programmable controller. After the equipment starts, the PLC continuously outputs control signals to drive the stepper motor 701 to run. The motor power changes the transmission direction through the bevel gear commutator 702, and then is synchronously transmitted to two sets of RXP lead screw lifting modules 704 through the universal drive shafts 703 on both sides. The two lead screws synchronously drive the lower horizontal air spray branch pipe assembly 6 and the lifting inner pipe 402 to move vertically as a whole. The vertical limit guide rail 8 on the inner side of the frame restricts the lateral displacement of the branch pipe assembly. The limit switches 9 at both ends of the guide rail monitor the running position in real time. When the branch pipe assembly reaches the upper and lower stroke limits, the limit switch 9 feeds back an electrical signal to the PLC, and the controller switches the motor direction to realize the continuous reciprocating sweeping of the air spray branch pipe in the set range.

[0047] During the full lifting and sliding of the inner tube 402, the four sets of wear-resistant pulleys 502 at the top continuously adhere to the inner wall of the outer tube 401, constraining the large radial sway of the inner tube from above; the four sets of spring-adjustable pulleys at the lower end of the fixed outer tube 401 simultaneously adhere to the outer wall of the inner tube 402, and the compression springs 505 continuously provide elastic clamping force, which can adapt to dimensional deviations caused by pipe processing and assembly, dynamically fine-tune the support distance, maintain the coaxial state of the inner and outer tubes, and generate only rolling friction throughout the entire process, reducing pipe wall scraping and jamming; the vertical load of the entire duct is borne entirely by the double screw lifting module, and the pulley mechanism is only responsible for radial limiting, and the two loads do not interfere with each other;

[0048] The annular limiting ring 3 on the inner wall of the lower end of the fixed outer tube 401 is located below the annular groove plate 12. The inner ring does not contact the outer wall of the lifting inner tube 402. It only provides physical obstruction when the sealing component moves abnormally downward, so as to prevent the sealing structure from falling out of the mating area. After the airflow from the nozzle and the material complete the temperature and humidity exchange, it flows back to the air supply fan 10 through the workshop return air duct, completing the closed-loop circulation of airflow, continuously and evenly regulating the drying and fermentation environment of each layer of material, and reducing the process differences between layers of material.

[0049] Among them, the frame, together with the limit rail 8 and the limit switch 9, provides a stable installation foundation and stroke protection for the entire mobile air duct, effectively avoiding the problems of lateral swaying and overtravel impact during the operation of the air duct;

[0050] Among them, the nested fixed outer tube 401 and the lifting inner tube 402 work together with the bottom multi-branch side air spray structure, and the airflow can move up and down with the tube body to sweep across the entire material rack, effectively improving the uneven air supply of multi-layer materials.

[0051] Among them, the pulley blocks arranged in upper and lower layers form radial constraints from the upper and lower ends of the tube body, effectively suppressing the swaying and eccentricity of the tube body during the lifting and lowering process;

[0052] Among them, the adjustable pulley assembly with spring and adjusting nut 507 can adaptively compensate for machining and assembly errors, effectively maintain the coaxial operation of the inner and outer sleeves, and reduce lifting friction resistance.

[0053] Among them, the labyrinth throttling section arranged sequentially along the airflow and the lip seal form a two-stage sealing structure, which effectively reduces air volume leakage under high-pressure air supply conditions.

[0054] Among them, the non-contact maze composed of 3 to 5 annular partitions 11 relies on airflow reversal to dissipate wind pressure, effectively reducing frictional loss of seals and making it suitable for clean food production environments.

[0055] Among them, the stainless steel pressure strip locking and fixing of the outer oblique lip sealing ring 13 only intercepts a small amount of residual airflow, with a smaller contact load, effectively delaying the aging and wear of the sealing components;

[0056] Among them, the stepper motor 701, commutator and universal drive shaft 703 work together with two sets of lead screw modules to achieve synchronous lifting and lowering, effectively ensuring that the air jet branch pipe maintains a horizontal posture during the lifting and lowering process.

[0057] Among them, the lower flange of the screw is rigidly connected to the air jet branch pipe, and the electrical components are uniformly connected to the PLC. The lifting speed and reciprocating range of the equipment can be flexibly adjusted to effectively adapt to the drying process requirements of different materials.

[0058] Among them, the annular limiting ring 3 at the lower end of the fixed outer tube 401 can provide lower protection for the sealing assembly, effectively reducing the operational risk of slippage failure of the sealing structure;

[0059] Among them, the coefficient of the compression spring 505 is 10-15 N / mm, the pre-compression amount is 2-3 mm, and the effective adjustment stroke is 5 mm;

[0060] The following is additional information:

[0061] I. Duct body dimensions, materials, and pipe structure parameters

[0062] 1. The vertical nested circular duct is made of 304 stainless steel and adopts a coaxial double circular tube sleeve telescopic structure; the fixed outer tube is 401 with a nominal diameter of φ250, and the lifting inner tube is 402 with a nominal diameter of φ200. The inner and outer tubes form an annular fitting gap to form a telescopic air supply main pipeline.

[0063] 2. The upper end of the fixed outer tube 401 is sealed and connected to the square standard ventilation duct through a flange structure. The outer tube is rigidly fixed to the top beam of the frame. The lifting inner tube 402 is coaxially nested inside the outer tube and can slide back and forth in the vertical direction. The lower end of the inner tube is rigidly welded and fixed to the horizontal air jet branch assembly 6.

[0064] 3. Design parameters for the length of the lifting inner tube 402: The total length of the lifting inner tube 402 is determined by two core dimensions: the height of the sealing section and the installation height of the fixed outer tube 401 above the ground. The formula for calculating the foundation length of the inner tube is: Inner tube length = length of the sealing section + height of the outer tube above the ground;

[0065] 4. Multiple horizontal air jet branches symmetrically branch off from the lower end of the 402 lifting inner pipe. Lateral spray holes are evenly opened on the pipe wall along its own length. The air outlet direction of the spray holes is horizontal or slightly downward, which is suitable for the lateral uniform air supply of materials on multi-layer carts. The specific dimensions of the branch pipes and spray holes are calculated and determined according to the air volume and air pressure conditions of the workshop air supply design.

[0066] 5. The equipment is equipped with conventional supply and return air ducts. The duct material can be selected from galvanized steel plate or 304 stainless steel plate according to the working conditions of the production workshop. It adopts the industry's general standard ventilation duct specifications, without customized sealing or flange modification structures, and only undertakes the function of airflow transmission and connection between the air handling unit and the vertical fixed external pipe 401.

[0067] II. Design parameters for lifting stroke and sleeve overlap length

[0068] 1. Lifting stroke design logic: The vertical reciprocating lifting stroke of the air duct is preset based on the effective height of the workshop material rack. The effective height of the rack does not include the height of the bottom rollers. Taking a typical embodiment as an example, the actual effective height of the rack is 1755mm. When three air supply branches are arranged on each side of the branch pipe, the height is evenly distributed to calculate the single-segment air supply coverage area. The single-segment height = 1755mm ÷ 3 = 585mm, and the corresponding air duct design lifting stroke is 585mm.

[0069] 2. Maximum overlap length of inner and outer pipes: When the inner and outer pipes are fully retracted and the branch pipe is at the upper limit position, the formula for calculating the maximum overlap length of the sleeve is: Maximum overlap length = lifting stroke length + sealing part length + 50mm safety margin.

[0070] 3. Minimum overlap length of inner and outer pipes: When the inner and outer pipes are fully extended and the branch pipe is at the lower limit position, the formula for calculating the minimum overlap length of the sleeve is: Minimum overlap length = length of sealing part + 50mm reserved safety margin; 50mm is a fixed safety overlap margin to ensure that the sealing structure is always completely within the annular mating area of ​​the inner and outer pipes at the limit expansion and contraction position, so as to avoid the seal from leaving the mating surface and causing a large amount of air leakage.

[0071] 4. Limit switches 9 are installed at both ends of the vertical guide rail of the frame. The installation position of the limit switches 9 is marked according to the preset lifting stroke size, which limits the air duct to only be able to circulate up and down within the designed stroke range, so as to achieve full coverage air supply for the corresponding material layers.

[0072] III. Gap, Material, and Assembly Parameters of Plate-Type Labyrinth Composite Sealing Structure

[0073] 1. The composite sealing mechanism is installed on the outer wall of the upper section of the inner pipe 402 and the annular mating area of ​​the inner and outer pipes. Multi-layer plate-type straight-through labyrinth throttling section and food-grade EPDM oblique lip sealing section are arranged sequentially from upstream to downstream along the airflow direction.

[0074] 2. The multi-layer plate-type straight-through labyrinth throttling section is composed of multiple annular plate-type baffles. The baffles are horizontally and parallelly welded to the outer wall of the inner tube. All baffles are arranged equidistantly and parallel along the axial direction of the air duct to form a long-path zigzag airflow pressure relief channel. A non-contact annular gap of 3mm to 5mm is reserved between each baffle and the inner wall of the fixed outer tube 401, and there is no friction contact of rubber parts throughout the entire process.

[0075] 3. The labyrinth sealing section can dissipate more than 95% of the air supply pressure and reduce the leakage air volume in the pipeline; the downstream of the labyrinth is equipped with a food-grade EPDM material external oblique lip sealing ring 13. The sealing ring is fixed by segmented stainless steel pressure strips and bolts. No adhesive is used in the assembly process. The sealing ring lip faces outward and downward and is lightly attached to the inner wall of the outer pipe to seal the residual leakage airflow of the labyrinth structure.

[0076] 4. The sealing system plays a role in leakage suppression under different working conditions: the non-contact labyrinth structure undertakes more than 90% of the leakage reduction and sealing function, and the lip seal serves as an auxiliary finishing seal. Compared with the traditional all-rubber contact sealing ring, the overall motion friction resistance is reduced by about 80%, and the pipeline leakage rate is reduced to less than 1 / 10 of the traditional sealing structure.

[0077] IV. Specifications and Adjustment Parameters of Double-Layer Adjustable Pulley Guide Mechanism

[0078] 1. The guiding mechanism is divided into an upper inner tube fixed pulley group and a lower outer tube spring adjustable pulley group. The two pulley groups only constrain the radial offset of the sleeve. The vertical load of the entire duct is completely borne independently by the top double screw lifting mechanism. The pulleys do not bear the vertical load.

[0079] 2. Upper inner guide pulley: Four sets of pulley brackets 501 are evenly arranged along the circumference at 90° on the outer wall of the top of the inner tube. Each set of brackets is equipped with a wear-resistant nylon pulley or a stainless steel pulley. The outer edge of the pulley is attached to and fixed to the inner wall of the outer tube 401 to achieve basic centering and suppress large radial sway of the inner tube.

[0080] 3. Lower External Adjustable Pulley Assembly: Four sets of independent adjustment components are evenly arranged along the circumference at 90° on the outer wall of the lower end of the outer pipe; each adjustment component includes a pulley body 504, a compression spring 505, an M6 locking bolt 506, and an adjusting nut 507; rotating the adjusting nut 507 can change the spring pre-compression amount, precisely adjust the radial extension of the pulley, compensate for the coaxiality error of the duct processing and assembly, and generate only rolling friction throughout the reciprocating lifting process, without any metal hard scraping or jamming problems;

[0081] V. Model, Configuration and Control Parameters of the Dual-Screw Synchronous Lifting Drive Mechanism

[0082] 1. The top crossbeam of the frame is equipped with a drive assembly, including a stepper motor 701, a bevel gear commutator 702, a universal drive shaft 703, and two sets of RXP type lead screw lifting modules; the power output of the stepper motor 701 is changed in transmission direction by the bevel gear commutator 702, and then synchronously distributed to the two sets of lead screw lifting modules through the universal drive shaft 703 to realize the synchronous lifting action of the two lead screws;

[0083] 2. The lower flange of the screw jack is rigidly connected to the horizontal air jet branch pipe frame. The entire vertical weight of the lifting inner pipe 402 and the horizontal air jet branch pipe is borne synchronously by the two screws. The guide pulley only serves as a radial limit. The load and the limit structure do not interfere with each other. The air jet branch pipe remains horizontal throughout the lifting process.

[0084] 3. The stepper motor 701 is equipped with a PLC programmable control system, which can customize the reciprocating lifting speed and lifting range stroke parameters of the air duct; limit switches 9 are installed at the upper and lower ends of the vertical guide rail of the frame, and the limit switches 9 are connected to the PLC control circuit of the whole machine, serving as a physical protection device for the maximum stroke of the air duct lifting, limiting the full stroke range of the air duct cyclic sweeping.

[0085] VI. Frame structure, limit and assembly dimensions related parameters

[0086] 1. The load-bearing frame adopts a rectangular integral structure welded from steel profiles. The top crossbeam of the frame is used to install the complete set of lifting drive transmission components. The inner side of the frame is integrally equipped with vertical limit guide rails 8 to constrain the lifting trajectory of the horizontal air spray branch pipe and prevent the branch pipe from deviating to the left or right.

[0087] 2. Limit switches 9 are fixed at the upper and lower ends of the vertical guide rail of the frame, and are connected to the PLC control system of the whole machine through the line. The installation position of the limit switch 9 is calibrated according to the preset lifting stroke, which limits the maximum stroke of the air duct to the up and down reciprocating movement. The air duct can only circulate up and down within the stroke range defined by the limit switch 9.

[0088] VII. Test parameters for overall machine operation performance

[0089] 1. The equipment uses PLC control to realize dynamic up-and-down reciprocating air sweeping of the air duct. The dynamic air supply mode can eliminate the dead zone of airflow stratification in multi-layer material racks. The temperature difference between material layers can be stably controlled within 0.5℃, solving the problems of inconsistent dehydration degree of upper and lower materials and uneven finished product quality caused by traditional fixed air duct fixed-point air supply.

[0090] 2. The sealing structure adopts a composite form with non-contact labyrinth as the main component and lip seal as the auxiliary component, which takes into account the dual requirements of low leakage and low motion friction under high pressure conditions, and avoids the defects of high friction loss of pure rubber contact seal and serious air leakage of ordinary gap seal; the double-layer adjustable pulley guide structure can maintain the coaxiality of inner and outer pipes throughout the process, and there are no eccentric jamming or wear problems during long-term reciprocating lifting and lowering, thus extending the overall service life of the equipment.

[0091] VIII. Assembly and Dimensional Parameters of the Whole Machine

[0092] 1. In the standard embodiment, the fixed outer tube 401 is made of pipe with a nominal diameter of φ250, and the lifting inner tube 402 is made of pipe with a nominal diameter of φ200. The top of the inner tube is welded with a guide pulley bracket 501, and the bottom of the inner tube is welded with four horizontal air spray branches with side spray holes. During assembly, the lifting inner tube 402 is coaxially inserted into the fixed outer tube 401 from bottom to top to complete the nested combination.

[0093] 2. Composite seal assembly sequence: Multi-layer annular baffle 11 is welded to the inner wall of the upper section of the φ250 outer tube, and the integrated annular EPDM outer oblique lip seal ring 13 is directly clamped downstream of the labyrinth structure; After the lower spring adjusting pulley assembly is assembled, the coaxiality of the inner and outer tubes is corrected by rotating the adjusting nut 507. After adjustment, the M6 ​​locking bolt 506 is tightened to fix the pulley extension.

[0094] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A vertically movable telescopic air supply duct with adjustable guiding and combined sealing, characterized in that, Includes frame assembly (1), fixed supply and return air duct (2), vertical nested circular duct body (4), upper and lower layered pulley guide mechanism (5), plate labyrinth lip composite sealing mechanism, double screw synchronous reciprocating lifting mechanism (7), and horizontal air jet branch assembly (6). The frame assembly (1) is a rectangular load-bearing frame welded from steel. The top crossbeam of the frame assembly (1) is fixed with a double screw synchronous reciprocating lifting mechanism (7). Two limit guide rails (8) are symmetrically and vertically fixed on the inner side of the frame assembly (1). Limit switches (9) are fixedly installed at the upper and lower ends of the limit guide rails (8). One end of the fixed supply and return air duct (2) is connected to the air supply fan (10). The other end of the fixed supply and return air duct (2) is flange-sealed and connected to the vertical nested circular air duct body (4). The vertical nested circular duct body (4) is installed inside the frame assembly (1). The outer wall of the vertical nested circular duct body (4) is equipped with an upper and lower layered pulley guide mechanism (5) and a plate-type labyrinth lip-shaped composite sealing mechanism. The lower end of the vertical nested circular duct body (4) is fixedly connected to the horizontal air jet branch assembly (6). The horizontal air jet branch assembly (6) is slidably connected to two limit guide rails (8). The output end of the double screw synchronous reciprocating lifting mechanism (7) is rigidly connected to the horizontal air jet branch assembly (6). The double screw synchronous reciprocating lifting mechanism (7) and the limit switch (9) are electrically connected to an external PLC programmable controller.

2. The vertically movable telescopic air supply duct with adjustable guide and composite seal according to claim 1, characterized in that, The vertical nested circular duct body (4) includes a fixed outer tube (401) and a lifting inner tube (402); the fixed outer tube (401) is rigidly fixed to the top crossbeam of the frame assembly (1), and the lifting inner tube (402) is coaxially nested inside the fixed outer tube (401). The lower end of the lifting inner tube (402) is rigidly connected to the horizontal air jet branch assembly (6); the horizontal air jet branch assembly (6) includes an outer frame (601) and multiple horizontal branch tubes (602) symmetrically arranged on the left and right sides at the lower end of the lifting inner tube (402). The pipe wall of the horizontal branch tube (602) is evenly opened with lateral spray holes along the length direction, and the lower end of the lifting inner tube (402) and the horizontal branch tube (602) are both located inside the outer frame (601) and are connected and fixed by multiple clamps (603). The two sides of the outer frame (601) are slidably connected to two limiting guide rails (8).

3. A vertically movable telescopic air supply duct with adjustable guide and composite seal according to claim 2, characterized in that, The upper and lower layered pulley guide mechanism (5) includes an upper inner tube fixed pulley group and a lower outer tube spring adjustable pulley group; the upper inner tube fixed pulley group is evenly arranged with four pulley brackets (501) at 90° along the outer wall of the top end of the lifting inner tube (402), and the pulley brackets (501) are equipped with wear-resistant pulleys (502), and the outer edge of the wear-resistant pulleys (502) is attached to the inner wall of the fixed outer tube (401).

4. A vertically movable telescopic air supply duct with adjustable guide and composite seal according to claim 3, characterized in that, The adjustable pulley assembly of the lower outer tube spring is evenly arranged with four sets of adjustment components at 90° along the lower outer wall of the fixed outer tube (401). Each set of adjustment components includes a mounting bracket (503), a pulley body (504), a compression spring (505), a locking bolt (506), and an adjusting nut (507). The mounting bracket (503) is evenly installed around the lower outer wall of the fixed outer tube (401), and a locking bolt (506) is movably inserted through the mounting bracket (503). 6) One end is fixedly connected to a movable pulley frame (508), and the movable pulley frame (508) is equipped with a pulley body (504). The adjusting nut (507) is screwed to the locking bolt (506). One side of the adjusting nut (507) abuts against the outer wall of the mounting bracket (503). The compression spring (505) is sleeved on the outside of the locking bolt (506). The two ends of the compression spring (505) are fixedly connected to the movable pulley frame (508) and the mounting bracket (503) respectively.

5. A vertically movable telescopic air supply duct with adjustable guide and composite seal according to claim 2, characterized in that, The plate-type labyrinth lip-shaped composite sealing mechanism is located in the annular mating area between the outer wall of the upper section of the lifting inner tube (402) and the inner wall of the fixed outer tube (401). The plate-type labyrinth lip-shaped composite sealing mechanism includes a multi-layer plate-type straight-through labyrinth throttling section and a food-grade EPDM oblique lip sealing section arranged sequentially along the airflow direction.

6. A vertically movable telescopic air supply duct with adjustable guide and composite seal according to claim 5, characterized in that, The multi-layer plate-type straight-through labyrinth throttling section is composed of multiple parallel annular baffles (11), the number of which is 3-5. The annular baffles (11) are horizontally welded to the outer wall of the lifting inner tube (402), and a 3-5mm annular gap is reserved between the annular baffles (11) and the inner wall of the fixed outer tube (401).

7. A vertically movable telescopic air supply duct with adjustable guide and composite seal according to claim 6, characterized in that, The food-grade EPDM oblique lip sealing section is provided with an annular groove plate (12), which is fixedly welded to the outer wall of the lifting inner tube (402). An outer oblique lip sealing ring (13) is provided inside the groove of the annular groove plate (12). The outer oblique lip sealing ring (13) is fixed by segmented stainless steel pressure strips and bolts. The outer oblique lip sealing ring (13) has its lip facing outward and downward to fit and fix the inner wall of the outer tube (401).

8. A vertically movable telescopic air supply duct with adjustable guide and composite seal according to claim 1, characterized in that, The dual-screw synchronous reciprocating lifting mechanism (7) includes a stepper motor (701), a bevel gear commutator (702), a universal drive shaft (703), and two sets of RXP screw lifting modules (704). The output end of the stepper motor (701) is connected to the bevel gear commutator (702), and the two sides of the bevel gear commutator (702) are respectively connected to the universal drive shaft (703). Each of the two universal drive shafts (703) is equipped with a set of RXP screw lifting modules (704), and the RXP screw lifting modules (704) are fixedly installed at the frame assembly (1).

9. A vertically movable telescopic air supply duct with adjustable guide and composite seal according to claim 8, characterized in that, The lower flanges of both sets of RXP screw lifting modules (704) are rigidly connected to the horizontal air jet branch pipe assembly (6); the stepper motor (701) and limit switch (9) are electrically connected to an external PLC programmable controller.

10. A vertically movable telescopic air supply duct with adjustable guide and composite seal according to claim 7, characterized in that, An annular retaining ring (3) is provided on the inner wall of the lower end of the fixed outer tube (401). The retaining ring (3) is located below the annular groove plate (12), and the inner ring size of the retaining ring (3) is smaller than the outer ring size of the annular groove plate (12). The inner ring of the retaining ring (3) does not contact the outer wall of the lifting inner tube (402).

Images