Film evaporator for treating high-viscosity materials

Abstract

The utility model discloses a film evaporator for processing high-viscosity materials, which comprises a barrel body extending along the vertical direction, a heating jacket arranged on the periphery of the barrel body, a feed port connected to the side wall of the upper part of the barrel body, a conical discharge barrel with a big upper part and a small lower part connected to the lower end of the barrel body, and a rotor arranged in an inner cavity of the barrel body and used for scraping the inner wall of the inner cavity of the barrel body, a rotor shaft is arranged along the axis of the rotor, a plurality of scraping blades are uniformly arranged on the periphery of the rotor shaft in a central symmetry manner, each scraping blade extends along a spiral line which is guided downwards, and the outer edge of each scraping blade is close to the inner wall of the barrel body; and a conical discharging paddle for pushing materials downwards is arranged on the periphery of the lower part of the rotor shaft, is positioned in an inner cavity of the conical discharging barrel and is matched with the inner cavity of the conical discharging barrel. According to the film evaporator, a liquid film can be uniformly spread and smoothly flows downwards, the evaporation efficiency is high, materials are prevented from being overheated or blocked, and long-term stable operation of equipment is guaranteed.

Description

Technical Field

[0001] The utility model relates to a thin film evaporator, in particular to a thin film evaporator for processing high-viscosity materials, and belongs to the technical field of evaporation and concentration equipment. Background Art

[0002] Thin-film evaporators are primarily used for material concentration, evaporation, distillation, and desolventization in industries such as petrochemicals, pharmaceuticals, and food processing. They offer high heat transfer coefficients, high evaporation intensity, short flow times, and operational flexibility, making them widely used across the industry. Conventional rotary thin-film evaporators primarily consist of a main shaft, a rotating scraper mechanism driven by the main shaft, a jacket, a cylinder, upper and lower heads, and a motor. The scraper is a key component of the rotary thin-film evaporator, rotating to form a uniform thin film of material on the heated surface, achieving efficient heat transfer and evaporation. The material enters the heating cylinder tangentially through the upper feed port and is evenly spread across the inner wall of the cylinder by a distribution ring. Driven downward by the rotating scraper, the material flows downward in a spiral film along the inner wall of the cylinder. Heat is provided by the heat medium in the outer jacket of the cylinder, which evaporates the light components in the material and discharges them through the upper outlet. The material concentrates as it flows downward, reaching the desired concentration and discharging through the lower cone at the bottom.

[0003] According to the requirements of process and materials, there are currently four main types of scrapers, namely movable scrapers, hinged scrapers, fixed scrapers and spiral scrapers.

[0004] The movable scraper is the most basic and common scraper type. Its specific structure is as follows: The scrapers are installed in the four scraper guide grooves of the rotor. Due to the centrifugal force of the rotating rotor, they are thrown radially toward the inner wall of the evaporator cylinder, while simultaneously moving in a circular motion with the rotor. This scraping motion causes the material to form a turbulent film-like flow on the evaporator wall, greatly improving the heat transfer coefficient. At the same time, this continuous scraping effectively prevents material overheating, dry wall formation, and scaling.

[0005] Both the fixed scraper and the spiral scraper are made of metal. The scraper is rigidly connected to the rotor. The length of the scraper is the same as the evaporator body. The gap between the rotating scraper and the inner wall of the evaporator body is only 1-2mm. It requires high processing and installation progress. It is suitable for evaporation, concentration, desolventization or purification of extremely high viscosity and easily foaming materials.

[0006] Hinged scrapers are suitable for materials prone to scaling on the heating surface. These scrapers are typically non-metallic and mounted on a rotating frame using a movable hinge. As the rotor rotates, centrifugal force presses the scrapers against the inner wall of the evaporator cylinder, where they slide at an angle, scraping the material into a thin film and preventing scaling. Elastic scrapers, on the other hand, utilize springs to ensure they adhere to the inner surface of the main cylinder once installed.

[0007] Highly viscous materials have poor fluidity and are unlikely to flow naturally down the cylinder wall due to their own weight alone. Furthermore, the uniformity and continuity of the liquid film formed on the inner wall of the heating cylinder gradually deteriorate as the viscosity increases. The shear field and viscosity distribution created by the evaporator's scraper structure and operating conditions are key to achieving a good film formation for non-Newtonian fluids within the evaporator.

[0008] Patent publication number CN 101362027B, "A Rotary Thin Film Evaporator," utilizes an improved hinged scraper for the rotor of the scraper thin film evaporator. When processing highly viscous materials, the absence of a gap between the scraper and the inner surface of the cylinder creates significant film resistance. Furthermore, the material easily adheres to the scraper and hinge, resulting in uneven force on the scraper, which affects film formation and degrades rotor balance, affecting proper operation of the equipment.

[0009] The material forms a circular wave at the leading edge of the scraper, achieving axial transmission. Within the gap between the scraper and the wall, it is subjected to high shear strain, causing it to be thinned and scraped into a thin film. Low-viscosity fluids can effectively exchange material between the circular wave and the liquid film within the gap. However, as the viscosity of the fluid increases, the viscosity of the fluid within the circular wave increases, its axial transmission speed decreases, and the material further accumulates. At this time, the relative speed of the circular wave fluid cross-section decreases, and the surface becomes uneven, reducing the chance of contact with the wall and thinning into a film. At the same time, high-viscosity fluids recover a high viscosity after thinning, requiring continuous and timely thinning to ensure the uniformity and integrity of the film. The front end of the scraper forms a certain angle with the tangent direction of the circle, which can assist in the spreading of the high-viscosity fluid film, effectively improving the uniformity and continuity of the liquid film.

[0010] For shear-thinning fluids, the fluid's initial high viscosity recovers when the shear strain decreases or even ceases. In research, this is reflected by a brief recovery of the material's viscosity between two scrapers. This recovery is short-lived, and the film thins again with the next scraper stroke. This requires timely film-thinning by the scrapers, such as adding a sufficient number of scrapers, to maintain the overall low viscosity of the thinned material, thereby ensuring a uniform film. Utility Model Content

[0011] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and utility model title of this application, and such simplifications or omissions shall not be used to limit the scope of the present invention.

[0012] In view of the above-mentioned and / or existing problems in the prior art, the poor fluidity of high-viscosity materials causes the liquid film on the inner wall of the heating cylinder to gradually deteriorate in uniformity and continuity as the viscosity increases, and is prone to scaling. The present utility model is proposed.

[0013] The purpose of the utility model is to provide a thin film evaporator for processing high-viscosity materials, with uniform liquid film spread, smooth downward flow, high evaporation efficiency, and prevention of material overheating or clogging, thereby ensuring long-term stable operation of the equipment.

[0014] In order to solve the above technical problems, the utility model provides a thin film evaporator for processing high-viscosity materials, including a cylinder extending vertically, a heating jacket provided on the outer periphery of the cylinder, a feed port connected to the upper side wall of the cylinder, a conical discharge cylinder with a larger upper portion and a smaller lower portion connected to the lower end of the cylinder, the inner cavity of the cylinder is provided with a rotor for scraping the inner wall thereof, a rotor shaft is provided along the axis of the rotor, a plurality of scraping blades are evenly and centrally symmetrically provided on the outer periphery of the rotor shaft, each scraping blade extends along a downward-guiding spiral line, and the outer edge of each scraping blade is close to the inner wall of the cylinder; a conical discharge paddle is provided on the lower outer periphery of the rotor shaft for pushing the material downward, and the conical discharge paddles are located in the inner cavity of the conical discharge cylinder and fit together.

[0015] As an improvement of the present invention, a discharge seat ring is fixed to the lower end of the conical discharge barrel, and the lower end of the rotor shaft is fixedly connected to a straightening and discharging mechanism by screws. The outer periphery of the center sleeve of the straightening and discharging mechanism is evenly connected with radial support rods, and the outer end of each radial support rod is respectively connected to a sliding wear-resistant block, and the outer end of each sliding wear-resistant block respectively abuts against the inner wall of the discharge seat ring.

[0016] As a further improvement of the present invention, each radial support rod is provided with an inclined pusher corner, and the root of each sliding wear-resistant block is respectively plugged into the end of the corresponding radial support rod and locked by a countersunk screw.

[0017] As a further improvement of the present invention, an annular cooling water channel is provided along the circumferential wall of the discharge seat ring, and a cooling water inlet and a cooling water outlet connected to the cooling water channel are respectively provided on both sides of the outer wall of the discharge seat ring.

[0018] As a further improvement of the present invention, the inner wall of the discharge seat ring is provided with a chrome-plated wear-resistant layer.

[0019] As a further improvement of the present invention, the feed port is symmetrically arranged and extends along the tangential direction of the cylinder, a feed distributor is provided on the upper part of the rotor at a height corresponding to the feed port, and a plurality of feed distribution blades are evenly arranged along the circumference of the feed distributor.

[0020] As a further improvement of the present invention, the outer edge of each scraping blade is provided with a square notch, and the square notches on adjacent scraping blades are staggered.

[0021] As a further improvement of the present invention, the main body of the rotor shaft is a steel pipe, and multiple support rings are evenly mounted along the length of the steel pipe; the roots of each scraper blade are surrounded by the outer periphery of the support ring to form a cylindrical shape and are welded to each other as a whole.

[0022] Compared with the existing technology, the utility model has achieved the following beneficial effects: 1. Under the rotation and downward push of the scraping blade, the high-viscosity fluid liquid film is assisted to spread, effectively improving the uniformity and continuity of the liquid film, preventing the material from being heated for a long time, over-evaporation, a sharp increase in material viscosity, increased resistance, high power consumption and even the risk of equipment stalling.

[0023] 2. Driven by the scraping blades, the material spirals from top to bottom along the inner wall of the heating cylinder, continuously evaporating and concentrating, and the viscosity of the material continues to increase, which means that its fluidity becomes further deteriorated. The inclination angle of the scraping blades can give the material a greater downward thrust. A conical discharging blade with a continuous transition to the scraping blade is set at the lower cone. The angle between the inclination direction of the conical discharging blade and the axial direction of the equipment is increased to give the material a greater downward thrust, ensuring smooth discharge of the material.

[0024] 3. The square notches on adjacent scraper blades are staggered to provide segmented shearing, preventing high-viscosity materials from rolling into columns and forming thin films under the rotation of the scraper blades, resulting in low evaporation efficiency and discharge concentration that does not meet process requirements; it also prevents columnar materials from growing larger and suddenly collapsing, causing large pieces of material to fall directly from the wall of the heating cylinder and block the discharge port, causing equipment shutdown.

[0025] 4. The sliding wear-resistant block supported under the rotor shaft plays a radial centering role and rotates with the rotor shaft to prevent material accumulation and blockage in this area; multiple circumferentially arranged sliding wear-resistant blocks are used at the bottom instead of bearings, which not only ensures the accurate centering of the rotor shaft, but also adopts plug-in installation, which is convenient for maintenance and disassembly; after the wear-resistant sliding block is worn, only this small part needs to be replaced, which reduces the cost of use and avoids sparks generated during the friction between steel and steel; the inner wall of the fixed seat ring is chrome-plated to increase the hardness, and a cooling water interlayer channel is set on the outside to cool the sliding block and increase its service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. 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 work. The drawings are only provided for reference and explanation, and are not intended to limit the present invention. Among them:

[0027] Figure 1 This is a front view of the thin film evaporator for processing high-viscosity materials according to the present invention;

[0028] Figure 2 A perspective view of the rotor in the present invention;

[0029] Figure 3 This is the front view of the rotor in the utility model;

[0030] Figure 4 for Figure 3 Enlarged cross-sectional view along the middle line AA;

[0031] Figure 5 for Figure 3 Magnified view of the base of the middle rotor;

[0032] Figure 6 It is a three-dimensional diagram of the straightening and discharging mechanism in the present utility model;

[0033] Figure 7 This is an enlarged cross-sectional view of the discharge seat ring in the present utility model;

[0034] In the figure: 1. Motor; 2. Transmission mechanism; 3. Motor base; 4. Machine base;

[0035] 5. Cylinder; 5a. Feed inlet; 5b. Air extraction port;

[0036] 6. Heating jacket; 6a. Steam inlet; 6b. Condensate outlet; 6c. Honeycomb short tube;

[0037] 7. Conical discharge barrel;

[0038] 8. Discharge seat ring; 8a. Cooling water inlet; 8b. Cooling water channel; 8c. Cooling water outlet;

[0039] 9. Rotor; 9a. Rotor shaft; 9b. Feed distributor; 9c. Support ring; 9d. Scraper blade; 9e. Conical discharge blade; 9f. Righting and discharge mechanism; 9f1. Radial support rod; 9f2. Sliding wear block. DETAILED DESCRIPTION

[0040] In the following description of the present invention, the terms "upper", "lower", "front", "back", "left", "right", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not mean that the device must have a specific direction.

[0041] In order to make the technical means, creative features, objectives and effects of the present invention easier to understand, the present invention is further described below with reference to specific figures. Obviously, the embodiments described are only a part of the present invention, not all of the embodiments.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0043] like Figures 1 to 7 As shown, the thin film evaporator for processing high-viscosity materials of the present invention includes a cylinder 5 extending vertically, the upper end of the cylinder 5 is fixed in the machine base 4, the upper end of the machine base 4 is fixed with a motor base 3, and the motor 1 and the transmission mechanism 2 are supported on the motor base 3.

[0044] A heating jacket 6 is installed around the outer periphery of the main body of the cylinder 5. The heating jacket 6 is arranged in sections, with a steam inlet 6a on the upper sidewall and a condensate outlet 6b on the lower sidewall. Steam enters the heating jacket 6 through the steam inlet 6a, heating the cylinder 5. After heat exchange, it becomes condensed water and is discharged through the condensate outlet 6b.

[0045] The heating jacket 6 is connected to the cylinder 5 by multiple honeycomb short tubes 6c. Compared with the traditional jacket joint, it has better overall strength, stronger pressure resistance, thinner cylinder wall thickness, improved heat transfer performance, and reduced equipment manufacturing cost.

[0046] A feed port 5a is connected to the side wall of the upper part of the cylinder that is higher than the heating jacket 6. The feed port 5a is symmetrically arranged and extends along the tangential direction of the cylinder. The inner cavity of the cylinder is provided with a rotor 9 for scraping the inner wall thereof. A feed distributor 9b is provided at the upper part of the rotor 9 at a height corresponding to the feed port 5a, and a plurality of feed distribution blades are evenly arranged along the circumference of the feed distributor 9b.

[0047] Motor 1 drives rotor 9 through transmission mechanism 2, which tangentially and symmetrically enters the cylinder cavity through feed port 5a. Feed distributor 9b on the rotor's upper surface quickly and evenly distributes the material around the entire circumference of the cylinder, improving evaporation efficiency. An exhaust port 5b is provided on the upper sidewall of the cylinder to facilitate the extraction of evaporated water vapor, small molecules, or light components.

[0048] Along the rotor's axis lies a rotor shaft 9a. Multiple scraper blades 9d are arranged symmetrically around the rotor shaft 9a. Each scraper blade 9d extends along a downward-directing spiral line, with its outer edge positioned close to the inner wall of the cylinder. This allows the material to be coated onto the inner wall, achieving thin-film evaporation and scraping the inner wall. Driven by the downward pressure angle of the spiral, highly viscous materials flow downward more smoothly. Each scraper blade 9d has a square notch on its outer edge. The staggered notches on adjacent scrapers 9d provide segmented shearing of the material, preventing it from rolling into a columnar shape under the rotation of the scraper blades 9d.

[0049] The rotor shaft 9a is constructed from a steel tube, with multiple support rings 9c uniformly positioned along its length. The roots of the scraper blades 9d are welded together to form a cylindrical shape around the outer circumference of the support rings 9c. This design enhances the rotor's overall rigidity, smooths the transition between the scraper blades, reduces welding distortion, and ensures machining accuracy. It also effectively reduces the surface area of ​​non-scraping areas on the scraper blades where material may adhere, preventing highly viscous materials from adhering to the roots of the scraper blades 9d. This significantly reduces the likelihood of material adhering to the blades during operation, enhances operational stability, and facilitates cleaning.

[0050] In order to further prevent the material from sticking to the surface of the scraper blade 9d, the outer surface of the rotor is polished as a whole, and the finish is not less than 0.4 microns.

[0051] The lower end of the cylinder is connected to a conical discharge cylinder 7 with a larger upper portion and a smaller lower portion. The lower periphery of the rotor shaft 9a is provided with a conical discharge blade 9e for pushing the material downward. The conical discharge blades 9e are located in the inner cavity of the conical discharge cylinder 7 and fit together.

[0052] A discharge seat ring 8 is provided below the flange of the discharge port of the conical discharge barrel 7, and a flange is also provided below the discharge seat ring 8. The two flanges clamp the discharge seat ring 8 by bolts, and the facing end faces of the two flanges are respectively embedded with sealing rings and the discharge seat ring 8 to achieve sealing.

[0053] The lower end of the rotor shaft 9a is screw-secured to a centering and discharging mechanism 9f. Radial support rods 9f1 are evenly connected to the outer circumference of the central sleeve of this mechanism. Each radial support rod 9f1 features an inclined pusher angle to facilitate downward push of material. The outer end of each radial support rod 9f1 is connected to a sliding wear-resistant block 9f2, made of a self-lubricating, impact-resistant non-metallic material.

[0054] The center sleeve is mounted on the lower end of the rotor shaft 9a through a key sleeve to achieve radial positioning. The screws are screwed into the center of the lower end of the rotor shaft 9a from bottom to top to fix the center sleeve. After unscrewing the screws, the straightening and discharging mechanism 9f can be removed. The size is greatly reduced compared to the existing structure, which is convenient for maintenance.

[0055] The root of each sliding wear-resistant block 9f2 is respectively inserted into the end of the corresponding radial support rod 9f1 and locked by a countersunk screw. The outer end of each sliding wear-resistant block 9f2 is respectively against the inner wall of the discharge seat ring 8. The sliding wear-resistant block 9f2 can be replaced individually by removing the countersunk screw, avoiding the overall replacement of the rotor components and reducing maintenance costs.

[0056] The inner wall of the discharge ring 8 is coated with a chrome-plated wear-resistant layer to enhance its wear resistance. Because friction between the sliding wear-resistant block 9f2 and the inner wall of the discharge ring 8 generates heat, an annular cooling water channel 8b is provided along the circumferential wall of the discharge ring 8. A cooling water inlet 8a and a cooling water outlet 8c, both connected to the cooling water channel 8b, are located on either side of the outer wall of the discharge ring 8. Cooling water is introduced into the cooling water channel 8b to dissipate the heat generated by friction and extend the service life of the sliding wear-resistant block 9f2.

[0057] The above description is only a preferred embodiment of the present invention, which shows and describes the basic principles, main features and advantages of the present invention, but does not limit the scope of patent protection of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. In addition to the above embodiments, the present invention may have other implementation methods without departing from the spirit and scope of the present invention. The present invention may also have various changes and improvements, and all technical solutions formed by equivalent replacement or equivalent transformation fall within the scope of protection required by the present invention. The scope of protection required by the present invention is defined by the attached claims and their equivalents. Technical features not described in the present invention can be achieved by or using existing technologies, and will not be described here.

Claims

1. A thin film evaporator for processing highly viscous materials, comprising a vertically extending cylinder, a heating jacket provided on the outer periphery of the cylinder, a feed port connected to the upper sidewall of the cylinder, a tapered discharge barrel with a larger upper portion and a smaller lower portion connected to the lower end of the cylinder, and a rotor provided within the inner cavity of the cylinder for scraping the inner wall thereof, characterized in that: A rotor shaft is provided along the axis of the rotor, and a plurality of scraping blades are evenly and symmetrically provided on the outer circumference of the rotor shaft. Each scraping blade extends along a downward-guiding spiral line, and the outer edge of each scraping blade is close to the inner wall of the cylinder; a conical discharging blade for pushing the material downward is provided on the lower outer circumference of the rotor shaft, and the conical discharging blades are located in the inner cavity of the conical discharging cylinder and coincide with each other.

2. The thin film evaporator for processing high-viscosity materials according to claim 1, characterized in that: A discharge seat ring is fixed to the lower end of the conical discharge barrel, and the lower end of the rotor shaft is fixedly connected to a straightening and discharging mechanism by screws. The outer periphery of the center sleeve of the straightening and discharging mechanism is evenly connected with radial support rods, and the outer end of each radial support rod is respectively connected to a sliding wear-resistant block, and the outer end of each sliding wear-resistant block respectively abuts against the inner wall of the discharge seat ring.

3. The thin film evaporator for processing high-viscosity materials according to claim 2, characterized in that: Each radial support rod is provided with an inclined material pushing corner portion, and the root portion of each sliding wear-resistant block is respectively plugged into the end of the corresponding radial support rod and is respectively locked by a countersunk screw.

4. The thin film evaporator for processing high-viscosity materials according to claim 2, characterized in that: An annular cooling water channel is provided along the circumferential wall of the discharge seat ring, and a cooling water inlet and a cooling water outlet connected to the cooling water channel are respectively provided on both sides of the outer wall of the discharge seat ring.

5. The thin film evaporator for processing high-viscosity materials according to claim 2, characterized in that: The inner wall of the discharge seat ring is provided with a chrome-plated wear-resistant layer.

6. The thin film evaporator for processing high-viscosity materials according to claim 1, characterized in that: The feed inlets are symmetrically arranged and extend along the tangential direction of the cylinder. A feed distributor is provided on the upper part of the rotor at a height corresponding to the feed inlet, and a plurality of feed distribution blades are evenly arranged along the circumference of the feed distributor.

7. The thin film evaporator for processing high-viscosity materials according to claim 1, characterized in that: The outer edge of each scraper blade is respectively provided with a square notch, and the square notches on adjacent scraper blades are staggered.

8. The thin film evaporator for processing high-viscosity materials according to any one of claims 1 to 7, characterized in that: The main body of the rotor shaft is a steel pipe, and a plurality of support rings are evenly mounted along the length of the steel pipe; the roots of the scraping blades are surrounded by the outer periphery of the support ring to form a cylindrical shape and are welded to each other to form a whole.

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