Oscillating scraped surface evaporator

Abstract

The present application relates to a kind of swing type blade evaporator, including shell, end plate being arranged at the both ends of the shell, further including doctor blade, doctor blade shaft, heat exchange plate, driving motor, the doctor blade shaft is arranged in the shell interior and both ends rotationally sealed on the end plate, multiple the doctor blade is fixedly arranged on the doctor blade shaft, multiple the heat exchange plate is fixedly arranged in the shell, multiple the doctor blade doctor blade blade is respectively located between multiple the heat exchange plate, the doctor blade shaft is located above the heat exchange plate, the driving motor is arranged on the end plate and drives the doctor blade to carry out swing movement with the doctor blade shaft as center.The present application not only reduces the initial investment of equipment and the operation and maintenance cost of whole life cycle, but also can meet the deep concentration demand of complex solution such as high viscosity, high salt, strong corrosion, heat sensitivity, etc., and is widely applicable in industry.

Description

A type of oscillating scraper evaporator Technical Field

[0001] This invention relates to the field of evaporation and concentration, and specifically to a swing-type scraper evaporator. Background Technology

[0002] In the chemical, environmental protection, and pharmaceutical industries, the deep concentration of complex solutions (such as landfill leachate, MVR mother liquor, and multi-effect evaporation residue) has always been a challenging problem. These solutions are rich in various salts and COD, exhibiting high viscosity, easy scaling, easy foaming, and high corrosiveness, severely limiting the applicability of conventional tubular and plate-type evaporation and concentration equipment. To address these issues, the industry has gradually developed horizontal scraper evaporation / crystallization equipment, as exemplified by patents / patent applications CN111803981A, CN200920210579.9, and CN201510444140.2. This equipment utilizes multiple parallel heat exchange plates within a horizontal shell, with rotating scrapers between the plates. A drive motor rotates the scrapers between the heat exchange plates, creating a stirring effect. This scraper-heat exchange plate structure is well-suited for evaporating complex solutions with high viscosity, high COD, and high calcium and magnesium content, enabling deep volume reduction and concentration of complex solutions. However, extensive engineering practice has shown that existing rotary scraper evaporators still have the following technical defects during production and use:

[0003] (1) Difficulty in adjusting and positioning the scraper: Existing technologies all adopt a rotary scraper structure design, with the scraper inside the heat exchange plate. The scraper fixing and position adjustment must be carried out within the narrow gap of the heat exchange plate, making the installation and maintenance of the equipment extremely difficult. The gap error between the heat exchange plate and the scraper is uncontrollable, and the production and equipment debugging takes a long time. (2) Problems of mechanical seal leakage and scraper shaft corrosion: The drive shaft and bearing sealing components of the existing scraper evaporator are all arranged below the liquid level line of the evaporator. Under the complex deep concentration of the liquid, the high chloride ion concentrate is highly corrosive to the scraper shaft. In order to solve the corrosion problem of the scraper shaft, the scraper shaft of the existing technology is generally made of titanium or duplex steel, resulting in a high initial investment in the equipment. In addition, particles and corrosive media in the liquid can easily enter the bearing sealing components, causing wear and failure of the equipment sealing components. (3) Scraper agitation The average Reynolds number is small and the coverage of the scraper on the heat exchange plate is low: The Reynolds number (Re) of the scraper evaporator is proportional to the radius of the scraper. The closer to the outer edge of the scraper, the higher the linear velocity of the scraper sweeping the plate at the same angular velocity, and the larger the Reynolds number of the scraper stirring. In the prior art, the stirring Reynolds number of the low-speed sweeping area near the shaft hole of the heat exchange plate is small, and the strengthening heat transfer effect of the scraper stirring on the heat exchange plate in this area is limited. In addition, in the prior art, the four corners of the heat exchange plate are prone to forming a cleaning blind zone of the scraper, resulting in the waste of the effective heat exchange area of ​​the heat exchange plate. (4) The material deposited in the bottom chamber is easy to cool down and caking, resulting in difficulty in discharge: During the evaporation process, the high-density concentrated material will be deposited in the bottom chamber of the evaporator. Since the bottom chamber lacks temperature maintenance means, high viscosity, high salt content or easy crystallization materials are very easy to caking and solidify after cooling down, resulting in blockage of the bottom chamber discharge port and affecting the normal discharge of the evaporator.

[0004] In summary, existing rotary scraper evaporators have certain technical deficiencies in terms of the ease of scraper adjustment, shaft corrosion resistance reliability, sealing system stability, and heat transfer efficiency, and cannot fully meet the needs of efficient and stable evaporation treatment of various complex liquids in the industrial field. Summary of the Invention

[0005] The present invention aims to provide a swing-type scraper evaporator to solve the problems existing in the prior art, such as difficulty in adjusting and positioning the scraper, mechanical seal leakage, shaft corrosion, low heat exchange plate coverage, and blind spots in cleaning. The technical problems to be solved by the present invention are achieved through the following technical solutions.

[0006] An oscillating scraper evaporator includes a shell and end plates disposed at both ends of the shell. The improvement lies in that it further includes scrapers, a scraper shaft, heat exchange plates, and a drive motor. The scraper shaft is disposed inside the shell and its two ends are rotatably sealed to the end plates. Multiple scrapers are fixedly disposed on the scraper shaft. Multiple heat exchange plates are fixedly disposed inside the shell. The scraper blades of the multiple scrapers are respectively located between the multiple heat exchange plates. The scraper shaft is located above the heat exchange plates. The drive motor is disposed on the end plates and drives the scrapers to oscillate around the scraper shaft.

[0007] Preferably, the end plate is provided with a bearing sealing assembly, and the scraper shaft is rotatably sealed to the end plate through the bearing sealing assembly.

[0008] Preferably, the drive motor drives the scraper to swing around the scraper shaft via the swing assembly.

[0009] Preferably, the oscillating assembly is a crankshaft connecting rod assembly, which includes a crank connected to and driven to rotate by the drive motor, a connecting rod rotatably connected to and driven to move by the crank, and an oscillating rod rotatably connected to and driven to oscillate around the scraper shaft. The scraper is provided with a scraper oscillating rod hole through which the oscillating rod passes. The oscillating rod passes through the scraper oscillating rod hole and drives the scraper to oscillate around the scraper shaft, and the scraper and the oscillating rod rotate relative to each other.

[0010] Preferably, the drive motor is connected to the scraper shaft via a coupling and drives the scraper shaft to rotate. The rotating scraper shaft causes the scraper to swing around the scraper shaft.

[0011] Preferably, the scraper includes a scraper shaft hole seat for being sleeved on the scraper shaft and fixedly connected to the scraper shaft, the scraper shaft hole seat and the scraper blade are connected by a scraper beam, and the scraper beam is provided with a scraper swing rod hole.

[0012] Preferably, the bottom of the housing is provided with a condensate jacket.

[0013] Preferably, the end plate is provided with a swing limit post for limiting the extreme swing position of the scraper.

[0014] Preferably, two parallel core support rails are symmetrically arranged on the lower inner wall of the housing along the length of the housing. A frame is provided on the core support rails, and multiple heat exchange plates are arranged on the frame and fixed inside the housing through the frame.

[0015] Preferably, the heat exchange plate is shaped as a three-sided straight line with a curved bottom edge and a convex top. The heat exchange plate is provided with a steam inlet branch pipe at the top and a condensate branch pipe at the bottom. The steam inlet branch pipes of multiple heat exchange plates are connected to the steam inlet main pipe located above the frame, and the condensate branch pipes of multiple heat exchange plates are connected to the condensate main pipe located below the frame.

[0016] This invention, by positioning the scraper shaft above the heat exchange plate and using a drive motor to drive the scraper to oscillate around the scraper shaft, achieves the basic evaporation and concentration functions of an evaporator while also providing the following beneficial effects:

[0017] 1) Easy adjustment of the gap between the scraper and the heat exchange plate: The scraper shaft is located above the heat exchange plate, and the space in which the heat exchange plate and the scraper are located is independent of each other. Unlike the existing rotary scraper with its shaft built-in design, the positioning and gap adjustment of the scraper can be completed in the open space (upper gas phase zone) of this invention. It can realize the independent adjustment of the gap of a specific scraper to adapt to the assembly error of the inter-plate channel of different heat exchange plates, and greatly shorten the equipment commissioning time.

[0018] 2) Improved operating conditions of shaft seal assembly and significantly reduced initial investment: The scraper shaft and bearing seal assembly of the present invention are located in the upper gas phase zone of the evaporator and do not come into direct contact with the liquid. This avoids the wear and erosion of the scraper shaft and bearing seal assembly by acidic, alkaline or chloride-containing corrosive liquids from the source, and significantly reduces the selection grade of shaft seal assembly materials and initial investment.

[0019] 3) Significantly improved scraper efficiency: The long scraper and scraper blades, combined with the oscillating reciprocating scraping trajectory, can completely cover the heat transfer surface of the vertical heat exchange plate, eliminating defects such as material scaling, adhesion, and bridging in the local blind spots of the heat exchange plate in current technology; the near-fan-shaped heat exchange plate is adapted to the oscillating trajectory of the scraper, and the scraper's sweeping coverage of the heat exchange plate is increased to more than 80%; the oscillating scraper has a large radius, resulting in a higher stirring linear velocity and Reynolds number for the liquid, which significantly enhances the heat transfer effect of the evaporator.

[0020] 4) Significantly improved bottom silo discharge: The bottom of the shell is equipped with a condensate jacket, which can maintain the temperature stability of the bottom silo area through the residual heat of the high-temperature condensate or the additional insulation medium, avoiding the caking, clumping or solidification of the concentrated liquid deposited in the bottom silo due to cooling; the condensate jacket can solve the problem of blockage at the bottom discharge port of the existing evaporator, reduce the frequency of manual cleaning and equipment downtime, and ensure the stability of continuous production.

[0021] 5) Optimization of overall equipment adaptability and operation and maintenance economy: By improving the design of components such as the scraper shaft and scraper, as well as the drive and swing mode, this invention forms a synergistic advantage in terms of compatibility with multiple specifications of liquids, adaptation to strong corrosive environments, and long-term stable operation. It not only reduces the initial investment and operation and maintenance costs throughout the entire life cycle of the equipment, but also meets the deep concentration needs of complex solutions such as high viscosity, high salt, strong corrosion, and heat sensitivity, and is applicable to a wide range of industries. Attached Figure Description

[0022] Figure 1 is a structural schematic diagram of Embodiment 1 of the present invention;

[0023] Figure 2 is a structural schematic diagram of Embodiment 1 of the present invention from another angle;

[0024] Figure 3 is a schematic diagram of the heat exchange plate in this invention;

[0025] Figure 4 is a front view schematic diagram of the scraper structure in this invention;

[0026] Figure 5 is a side view of the scraper structure in this invention;

[0027] Figure 6 is a schematic diagram of the crankshaft connecting rod assembly and scraper in Embodiment 1 of the present invention (along the AA direction in Figure 1).

[0028] Figure 7 is a schematic diagram of the left stop position of the scraper swing in Embodiment 1 of the present invention;

[0029] Figure 8 is a schematic diagram of the right stop position of the scraper swing in Embodiment 1 of the present invention;

[0030] Figure 9 is a structural schematic diagram of Embodiment 2 of the present invention;

[0031] The reference numerals in the attached figures are as follows: 1. Shell, 2. End plate, 3. Secondary steam outlet, 4. Feed inlet, 5. Steam inlet pipe, 6. Steam main pipe, 7. Frame, 8. Core support rail, 9. Condensate outlet pipe, 10. Discharge outlet, 11. Condensate main pipe, 12. Heat exchange plate, 121. Steam branch pipe, 122. Condensate branch pipe, 13. Scraper, 131. Scraper shaft hole seat, 132. Scraper swing rod hole, 133. Scraper beam, 134. Scraper blade, 135. Scraper positioning hole, 14. Crankshaft connecting rod assembly, 141. Crank, 142. Connecting rod, 143. Swing rod, 15. Drive motor, 16. Bearing sealing assembly, 17. Scraper shaft, 18. Swing limit post, 19. Condensate jacket. Detailed Implementation

[0032] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0033] Example 1:

[0034] Referring to Figures 1 to 8, a swing-type scraper evaporator includes a housing 1 and end plates 2 disposed at both ends of the housing 1. The improvement lies in that it further includes scrapers 13, scraper shafts 17, heat exchange plates 12, and a drive motor 15. The scraper shaft 17 is disposed inside the housing 1 and its two ends are rotatably sealed to the end plates 2. Multiple scrapers 13 are fixedly disposed on the scraper shaft 17, and multiple heat exchange plates 12 are fixedly disposed inside the housing 1. The scraper blades 134 of the multiple scrapers 13 are respectively located between the multiple heat exchange plates 12. The scraper shaft 17 is located above the heat exchange plates 12. The drive motor 15 is disposed on the end plates 2 and drives the scrapers 13 to swing around the scraper shaft 17.

[0035] Further, referring to Figures 1 and 2, the end plate 2 includes a left end plate and a right end plate located at the left and right ends of the housing 1. The end plate 2 is connected to the housing 1 by a flange. The left end plate is provided with a DN100 sight glass, and the right end plate is provided with a DN600 manhole. The housing 1 is a cylindrical structure made of carbon steel-titanium composite plate. The inner diameter of the cylinder is 2500mm, the length is 4000mm, and the exterior is provided with circumferential reinforcing ribs. The top of the housing 1 is provided with a DN500 secondary steam outlet 3 and a DN50 feed inlet 4. The side wall of the housing 1 is provided with a DN200 steam inlet pipe 5, and the bottom of the housing 1 is provided with a DN200 discharge outlet 10.

[0036] Furthermore, the interior of the shell 1 is divided into an upper gas phase zone, a middle heat exchange zone, and a lower deposition zone; the height of the upper gas phase zone is 1 / 3 to 1 / 2 of the total height of the shell, and the height of the lower deposition zone is 1 / 5 to 1 / 4 of the total height of the shell. Even further, the height of the upper gas phase zone is approximately 1200 mm, and the height of the lower deposition zone is approximately 200 mm.

[0037] Furthermore, the system also includes a control system, which comprises a PLC controller, a level gauge, a thermometer, a pressure gauge, and a flow meter. The level gauge is a non-contact radar level gauge, installed on the top of the housing 1, for monitoring the liquid level. The thermometer and pressure gauge are respectively installed on the housing 1, the steam pipeline, and the condensate pipeline for monitoring temperature and pressure parameters. The flow meter is installed on the feed, steam, and discharge pipelines for monitoring flow parameters. Based on the collected parameters, the PLC controller uses a PID algorithm to adjust the speed of the drive motor 15, the steam flow rate, the feed rate, and the discharge rate to ensure stable equipment operation.

[0038] This embodiment, by positioning the scraper shaft 17 above the heat exchange plate 12 and using the drive motor 15 to drive the scraper 13 to swing around the scraper shaft 17, achieves the basic evaporation and concentration functions of the evaporator while also having the following beneficial effects:

[0039] The gap between the scraper and the heat exchange plate is easy to adjust: The scraper shaft 17 is located above the heat exchange plate 12. The heat exchange plate 12 and the scraper 13 are in independent spaces. Unlike the existing rotary scraper with its shaft built-in design, the positioning and gap adjustment of the scraper 13 in this embodiment can be completed in the open space (upper gas phase zone). This allows for independent adjustment of the gap between a specific scraper to accommodate the assembly errors of the inter-plate channels of different heat exchange plates, significantly shortening the equipment commissioning time.

[0040] Improved operating conditions of shaft seal assembly and significantly reduced initial investment: In this embodiment, the scraper shaft 17 and bearing seal assembly 16 are both located in the upper gas phase zone of the evaporator and do not come into direct contact with the liquid. This avoids the wear and erosion of the scraper shaft 17 and bearing seal assembly 16 by acidic, alkaline or chloride-containing corrosive liquids from the source, and significantly reduces the selection grade of shaft seal assembly material and initial investment.

[0041] Furthermore, referring to Figures 2 and 6, the end plate 2 is provided with a bearing sealing assembly 16, and the scraper shaft 17 is rotatably sealed on the end plate 2 through the bearing sealing assembly 16.

[0042] Furthermore, the scraper shaft 17 is located in the upper gas phase region inside the housing 1; the scraper shaft 17 is made of carbon steel with an anti-corrosion coating, or carbon steel with laser cladding of 2209 stainless steel or 316L stainless steel; the shaft diameter of the scraper shaft 17 is 120mm; the bearing sealing assembly 16 is sealed using a carbon ring seal, a stuffing box seal, or a silicon carbide single-end mechanical seal.

[0043] Furthermore, referring to Figures 1, 6, 7, and 8, the drive motor 15 drives the scraper 13 to swing around the scraper shaft 17 via the swing assembly.

[0044] In this embodiment, the swing assembly can be a crankshaft connecting rod assembly, a cam drive assembly, a gear and rack assembly, or a stepper motor direct drive assembly. Any swing assembly that can convert the rotation of the drive motor 15 into the swing of the scraper 13 is acceptable.

[0045] Furthermore, the swing assembly is a crankshaft connecting rod assembly 14, which includes a crank 141 connected to and driven to rotate by the drive motor 15, a connecting rod 142 rotatably connected to and driven to move by the crank 141, and a swing rod 143 rotatably connected to and driven to swing about the scraper shaft 17. The scraper 13 is provided with a scraper swing rod hole 132 through which the swing rod 143 passes. The swing rod 143 passes through the scraper swing rod hole 132 and drives the scraper 13 to swing about the scraper shaft 17, and the scraper 13 and the swing rod 143 rotate relative to each other.

[0046] Furthermore, the drive motor 15 is a YVP series variable frequency motor with a power of 30kW. The drive motor 15 is connected to the hardened gear reducer through a flexible coupling. The output shaft of the hardened gear reducer is connected to the crank 141 of the crankshaft connecting rod assembly 14.

[0047] Furthermore, the crank 141, connecting rod 142, and swing rod 143 are all made of 2205 duplex steel. The length of the crank 141 is 152mm, the length of the connecting rod 142 is 354mm, and the length of the swing rod 143 is 3900mm. The crank 141 is fixed to the end plate 2 by bearings and is keyed to the output shaft of the hardened gear reducer. Both ends of the connecting rod 142 are rotatably connected to the crank 141 and the swing rod 143 respectively by universal joints. In this embodiment, the swing frequency of the swing rod 143 is 35 times / minute, and the swing angle range is ±48°.

[0048] Furthermore, referring to Figures 4 and 5, the scraper 13 includes a scraper shaft hole seat 131 for being sleeved on the scraper shaft 17 and fixedly connected to the scraper shaft 17. The scraper shaft hole seat 131 and the scraper blade 134 are connected by a scraper beam 133, and the scraper beam 133 is provided with a scraper swing rod hole 132.

[0049] Furthermore, the width of the scraper blade 134 is adapted to the gap between adjacent heat exchange plates 12, and the length of the scraper 13 is adapted to the radial length of the heat exchange plate 12.

[0050] Furthermore, referring to Figures 4 and 5, the scraper 13 adopts a single-blade paddle structure and is made of titanium. The total length of the scraper 13 is 1350mm, and the length of the scraper blade 134 is 1000mm and the width is 70mm. The scraper 13 is positioned and fixed to the scraper shaft 17 through the scraper positioning hole 135 located on the scraper shaft hole seat 131.

[0051] The long scraper and scraper blades, combined with the oscillating reciprocating scraping trajectory, can completely cover the heat transfer surface of the vertical heat exchange plate, eliminating defects such as material scaling, adhesion, and bridging in the local blind spots of the heat exchange plate in current technology; the near-fan-shaped heat exchange plate 12 is matched with the oscillating trajectory of the scraper 13, and the sweeping coverage of the scraper 13 on the heat exchange plate 12 is increased to more than 80%; the oscillating scraper 13 has a large radius, and the stirring linear velocity and Reynolds number of the liquid are high, which significantly enhances the heat transfer effect of the evaporator.

[0052] Furthermore, referring to Figures 1, 7, and 8, the bottom of the housing 1 is provided with a condensate jacket 19.

[0053] Furthermore, the thickness of the condensate jacket 19 is 8mm, and a DN50 condensate outlet pipe 9 is provided on the outside of the condensate jacket 19. In this embodiment, the high-temperature condensate in the condensate main pipe 11 flows into the condensate jacket 19, and the high-temperature condensate is used to keep the liquid in the lower deposition zone of the shell 1 warm.

[0054] In this embodiment, a condensate jacket 19 is provided at the bottom of the shell 1. The temperature of the bottom compartment area of ​​the shell 1 can be maintained by the residual heat of the high-temperature condensate or by the additional heat-insulating medium, so as to avoid the caking, clumping or solidification of the concentrated liquid deposited in the bottom compartment due to cooling. The condensate jacket 19 can solve the problem of blockage of the discharge port of the bottom compartment of the existing evaporator, reduce the frequency of manual cleaning and equipment downtime, and ensure the stability of continuous production.

[0055] Furthermore, referring to Figures 1, 7, and 8, the end plate 2 is provided with a swing limiting post 18 for limiting the extreme swing position of the scraper 13.

[0056] Furthermore, the swing angle range of the scraper 13 is limited to ±30°~±60° by the swing limiting post 18; even further, the swing angle range of the scraper 13 is ±48°.

[0057] Furthermore, referring to Figures 1, 7, and 8, two parallel core support rails 8 are symmetrically arranged on the lower inner wall of the housing 1 along the length direction of the housing 1. A frame 7 is provided on the core support rails 8, and multiple heat exchange plates 12 are arranged on the frame 7 and fixed inside the housing 1 through the frame 7.

[0058] Furthermore, the frame 7 is welded from 2205 duplex square steel, and 33 equidistant positioning slots with a spacing of 80mm are opened on the inner side along its length direction.

[0059] Furthermore, the core support rail 8 is made of 2205 angle steel.

[0060] Furthermore, referring to Figure 3, the heat exchange plate 12 is shaped as a three-sided straight line with a curved bottom edge and a convex shape at the top. The heat exchange plate 12 is provided with a steam inlet branch pipe 121 at the top and a condensate branch pipe 122 at the bottom. The steam inlet branch pipes 121 of the multiple heat exchange plates 12 are all connected to the steam inlet main pipe 6 located above the frame 7, and the condensate branch pipes 122 of the multiple heat exchange plates 12 are all connected to the condensate main pipe 11 located below the frame 7.

[0061] Furthermore, the heat exchange plate 12 has a length of 2000mm and a bottom arc height of 1000mm; the heat exchange plate 12 has a honeycomb bulging hollow structure and is made of titanium; each heat exchange plate 12 has a steam inlet branch pipe 121 with a diameter of DN45 at the top and a condensate branch pipe 122 with a diameter of DN25 at the bottom; multiple heat exchange plates 12 are inserted parallel and equidistantly into the slots of the frame 7, multiple steam inlet branch pipes 121 are connected to the steam inlet main pipe 6, multiple condensate branch pipes 122 are connected to the condensate main pipe 11, the steam inlet main pipe 6 is connected to the steam inlet pipe 5, the condensate main pipe 11 is connected to the condensate jacket 19, and the condensate is discharged through the condensate outlet pipe 9 on the condensate jacket 19, thereby forming a parallel heating channel of the heat exchange plate 12.

[0062] This embodiment improves the design of components such as the scraper shaft and scraper, as well as the driving and oscillation methods, forming synergistic advantages in terms of compatibility with multiple specifications of liquids, adaptability to highly corrosive environments, and long-term stable operation. It not only reduces the initial investment and maintenance costs throughout the entire life cycle of the equipment, but also meets the deep concentration requirements of complex solutions such as high viscosity, high salt, strong corrosion, and heat sensitivity, making it applicable to a wide range of industries.

[0063] This embodiment uses the deep concentration process of high-COD wastewater containing mixed salts from a chemical plant as an application scenario. Feed liquid physical properties: viscosity 150 mPa·s (25℃), COD content 80000 mg / L, Cl... - The concentration is 5000 mg / L, and the feed concentration is approximately 12%. The discharge concentration is required to be no less than 35%, and the evaporation rate is required to be no less than 5 t / h.

[0064] In this embodiment, wastewater raw material liquid is injected into the shell 1 through the feed inlet 4, and feeding is stopped after the liquid surface completely submerges the heat exchange plates 12; steam at a temperature of 120°C and a pressure of 0.2 MPa (A) is introduced into each heat exchange plate 12 through the steam inlet pipe 5; the drive motor 15 is started, and its speed is set to 35 rpm through the frequency converter. The drive motor 15 drives the crank 141 to rotate, and the connecting rod 142 drives the swing rod 143 to reciprocate; each scraper 13, driven by the swing rod 143, reciprocates within the gap of the heat exchange plates 12 around the scraper shaft 17, with an amplitude of ±4. The scraper 13 oscillates at 8° and a frequency of 35 times / minute to enhance heat exchange between the liquid and the steam in the heat exchange plate 12, while ensuring the cleanliness of the surface of the heat exchange plate 12. When the liquid is heated to about 103~105°C, it begins to evaporate, and the secondary steam is discharged from the evaporator through the secondary steam outlet 3. The condensate in the heat exchange plate 12 is collected by the condensate manifold 11 and discharged into the condensate jacket 19. The condensate insulates the liquid at the bottom of the shell 1. The condensate is discharged from the shell 1 through the condensate outlet 9. When the solid content of the liquid in the shell 1 is greater than 35%, all the liquid is discharged through the outlet 10, and the next batch of feeding and evaporation begins.

[0065] The oscillating scraper evaporator of this embodiment reduces the scraper adjustment time by 80% compared to existing equipment, and the adjustment and positioning of a single scraper's fit gap only takes about 5 minutes. The manufacturing cost of the scraper shaft is reduced by more than 50% compared to a pure titanium shaft, and the procurement cost of sealing components is reduced by about 70%. Engineering practice results show that the evaporator operates continuously for 720 hours, with an average evaporation rate of 6.7 t / h, exceeding the design requirements by 34%. The discharge concentration is about 37.8%, meeting the process requirements, with a feed concentration ratio of 3.2 and a discharge viscosity of 500 mPa·s. The scraper sweeps and covers 86% of the heat exchange plate, with no obvious scaling blind spots. The total heat transfer coefficient of the evaporator reaches 1850 W / (m²·℃). There is no leakage in the bearing sealing components, no blockage at the discharge port, smooth discharge, and no equipment downtime.

[0066] Comparative example:

[0067] The feed liquid treated in this comparative example is the same as that in Example 1, which is high-COD wastewater containing mixed salts from a chemical plant. The feed viscosity is 150 mPa·s (25℃), COD content is 80000 mg / L, and Cl... - The feed concentration is 5000 mg / L, and the discharge concentration is approximately 12%. The discharge concentration is required to be no less than 35%.

[0068] This comparative example uses a conventional rotary scraper evaporator with 1200mm heat exchange plates. The heat exchange plates are 1200mm square, with the scraper shaft hole located at the intersection of the diagonals of the heat exchange plates. The scraper shaft passes through each heat exchange plate, and the scraper rotates circumferentially between the heat exchange plates. The scraper is a two-blade straight blade scraper with a blade rotation diameter of 1000mm.

[0069] The comparison results of the equipment structure and operating performance between this comparative example and Example 1 are shown in the table below:

[0070] Table 1. Comparison results between the comparative example and Example 1

[0071]

[0072] In summary, Example 1, through its swing-type transmission design and the arrangement of the scraper shaft and bearing sealing assembly in the gas phase zone, effectively solves key problems in existing rotary scraper evaporators, such as difficult scraper adjustment, shaft corrosion, and seal failure. Combined with a fully covered single-blade scraper and a condensate insulation structure at the bottom of the shell, it significantly improves heat transfer efficiency and discharge smoothness, while also significantly reducing initial investment and maintenance costs. Example 1 demonstrates superior evaporation rate, concentration ratio, and operational stability compared to existing equipment in complex solution concentration scenarios involving high viscosity, high COD, and strong corrosion, making it suitable for the needs of multiple industries, including chemical, environmental protection, and pharmaceutical. This example achieves performance breakthroughs through structural optimization, providing an efficient and reliable technical solution for the deep concentration of complex solutions, and possesses broad prospects for industrial application and practical value.

[0073] Example 2:

[0074] The difference between this embodiment and Embodiment 1 is that this embodiment uses a stepper motor to directly drive the oscillation of the scraper shaft 17. Referring to Figure 9, the drive motor 15 is connected to the scraper shaft 17 via a coupling and drives the scraper shaft 17 to rotate. The rotating scraper shaft 17 causes the scraper 13 to oscillate around the scraper shaft 17. The rest is the same as in Embodiment 1 and will not be described again.

[0075] Furthermore, the drive motor 15 is a two-phase hybrid stepper motor with a power of 30kW and a step angle of 1.8°. The drive motor 15 is equipped with a digital stepper driver, and the microstepping factor is set to 100 through a DIP switch, that is, the minimum output step angle of the stepper motor is 0.018°, so as to achieve precise control of the scraper swing angle. The drive motor 15 is directly connected to the scraper shaft 17 through a coupling. The forward and reverse rotation and rotation angle of the drive motor 15 are controlled by a PLC controller.

[0076] This embodiment uses the concentration process of traditional Chinese medicine extract in a pharmaceutical company as an application scenario. Feed liquid properties: The feed liquid contains flavonoid active ingredients and is characterized by easy foaming and high viscosity; the viscosity at room temperature is approximately 800 mPa·s. The discharge concentration is required to be ≥35%, and there should be no coking or scaling issues during equipment operation.

[0077] In this embodiment, during operation, the traditional Chinese medicine extract is injected into the shell 1 through the feed inlet 4 at the top of the shell 1. During the feeding process, the liquid level is monitored in real time by a non-contact radar level gauge at the top. Feeding is stopped when the liquid surface completely submerges the heat exchange plate 12 to ensure full contact between the liquid and the heat exchange plate 12. Low-pressure steam at 105°C is introduced into the heat exchange plate 12 through the steam inlet pipe 5 on the side wall of the shell. The steam is distributed to the steam inlet branch pipes 121 of each heat exchange plate 12 through the steam inlet main pipe 6, and enters the honeycomb bulging hollow structure of the heat exchange plate 12 to exchange heat with the traditional Chinese medicine extract outside. The condensate after heat exchange is collected in the condensate main pipe 11 through the condensate branch pipe 122 at the bottom of the heat exchange plate 12, and finally enters the condensate jacket 19 at the bottom of the shell 1. The residual heat of the condensate is used to keep the deposited liquid at the bottom of the shell 1 warm. The condensate is discharged from the evaporator through the condensate outlet pipe 9. The stepper motor is started, and the digital stepper driver receives the instruction signal from the PLC controller. According to the preset parameters, the motor's basic step angle of 1.8° is accurately converted into the minimum output step angle of 0.018°. After the stepper motor runs 2660 steps, the scraper 13 swings 47.88° to the left along the vertical direction, reaching the left stop position of the scraper 13 swing. Then, the stepper motor is controlled to rotate counterclockwise, and 5320 pulse signals are output to the stepper motor through the stepper driver. At this time, the scraper swings to the right side of the vertical line at 47.88°, reaching the right stop position of the scraper swing. The drive motor runs in a cycle between forward and reverse, realizing the scraper's reciprocating swing of 35 times / minute.

[0078] Driven precisely by a stepper motor, the scraper 13 reciprocates across the surface of the heat exchange plate 12. This enhances convective heat transfer between the liquid and the heat exchange plate 12, accelerating the evaporation of the liquid at around 80°C. Simultaneously, it thoroughly removes the liquid adhesion layer from the surface of the heat exchange plate 12, preventing the coking of heat-sensitive components. The secondary steam generated during evaporation is discharged through the secondary steam outlet 3 at the top of the shell 1 and enters the subsequent condensation system. Once the PLC controller detects that the solid content of the liquid exceeds 35% using relevant sensors, it discharges the concentrated herbal extract from the shell 1. During the discharge process, the condensate jacket 19 maintains its temperature to ensure smooth and unobstructed discharge. After discharge, the next batch of evaporation begins.

[0079] In this embodiment, a stepper motor is directly coupled to the scraper shaft 17. Compared with the crankshaft connecting rod assembly used in Embodiment 1, this embodiment has advantages such as a shorter transmission path, lower mechanical loss, higher transmission efficiency, and a more compact equipment structure. The high-precision speed and angle control capability of the stepper motor ensures that the scraper 13 operates uniformly and stably between the heat exchange plates 12.

[0080] It should be noted that the above detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0081] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments described in this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0082] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0083] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or apparatus.

[0084] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways, such as rotated 90 degrees or in other orientations, and the spatial relative descriptions used herein will be interpreted accordingly.

[0085] In the detailed description above, reference has been made to the accompanying drawings, which form part of this document. In the drawings, similar symbols typically identify similar parts unless the context otherwise indicates otherwise. The illustrated embodiments described in the detailed specification, drawings, and claims are not intended to be limiting. Other embodiments may be used and other changes may be made without departing from the spirit or scope of the subject matter presented herein.

[0086] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A swing-type scraped evaporator, comprising a shell (1) and end plates (2) disposed at both ends of the shell (1), characterized in that: It also includes a scraper (13), a scraper shaft (17), a heat exchange plate (12), and a drive motor (15). The scraper shaft (17) is located inside the housing (1) and its two ends are rotatably sealed on the end plate (2). Multiple scrapers (13) are fixedly mounted on the scraper shaft (17). Multiple heat exchange plates (12) are fixedly mounted inside the housing (1). The scraper blades (134) of the multiple scrapers (13) are respectively located between the multiple heat exchange plates (12). The scraper shaft (17) is located above the heat exchange plates (12). The drive motor (15) is mounted on the end plate (2) and drives the scrapers (13) to swing around the scraper shaft (17).

2. The oscillating scraper evaporator according to claim 1, characterized in that: The end plate (2) is provided with a bearing sealing assembly (16), and the scraper shaft (17) is rotatably sealed on the end plate (2) through the bearing sealing assembly (16).

3. The oscillating scraper evaporator according to claim 1, characterized in that: The drive motor (15) drives the scraper (13) to swing around the scraper shaft (17) via the swing assembly.

4. A swing-type scraper evaporator according to claim 3, characterized in that: The swing assembly is a crankshaft connecting rod assembly (14). The crankshaft connecting rod assembly (14) includes a crank (141) connected to the drive motor (15) and driven to rotate by the drive motor (15), a connecting rod (142) rotatably connected to the crank (141) and driven to move by the crank (141), and a swing rod (143) rotatably connected to the connecting rod (142) and driven to swing around the scraper shaft (17). The scraper (13) is provided with a scraper swing rod hole (132) through which the swing rod (143) passes. The swing rod (143) passes through the scraper swing rod hole (132) and drives the scraper (13) to swing around the scraper shaft (17), and the scraper (13) and the swing rod (143) rotate relative to each other.

5. A swing-type scraper evaporator according to claim 1, characterized in that: The drive motor (15) is connected to the scraper shaft (17) via a coupling and drives the scraper shaft (17) to rotate. The rotating scraper shaft (17) drives the scraper (13) to swing around the scraper shaft (17).

6. A swing-type scraper evaporator according to claim 1, characterized in that: The scraper (13) includes a scraper shaft hole seat (131) for being sleeved on the scraper shaft (17) and fixedly connected to the scraper shaft (17). The scraper shaft hole seat (131) and the scraper blade (134) are connected by a scraper beam (133). The scraper beam (133) is provided with a scraper swing rod hole (132).

7. A swing-type scraper evaporator according to claim 1, characterized in that: The bottom of the housing (1) is provided with a condensate jacket (19).

8. A swing-type scraper evaporator according to claim 1, characterized in that: The end plate (2) is provided with a swing limit post (18) for limiting the extreme swing position of the scraper (13).

9. A swing-type scraper evaporator according to claim 1, characterized in that: Two parallel core support rails (8) are symmetrically arranged on the lower inner wall of the shell (1) along the length direction of the shell (1). A frame (7) is provided on the core support rails (8). Multiple heat exchange plates (12) are arranged on the frame (7) and fixed inside the shell (1) through the frame (7).

10. A swing-type scraper evaporator according to claim 1, characterized in that: The heat exchange plate (12) is shaped as a straight line on three sides and an arc at the bottom, with a convex shape at the top. The heat exchange plate (12) is provided with a steam inlet branch pipe (121) at the top and a condensate branch pipe (122) at the bottom. The steam inlet branch pipes (121) of the multiple heat exchange plates (12) are all connected to the steam inlet main pipe (6) located above the frame (7), and the condensate branch pipes (122) of the multiple heat exchange plates (12) are all connected to the condensate main pipe (11) located below the frame (7).

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