A sludge dryer blade with enhanced heat transfer on both sides

Abstract

The present application belongs to the technical field of sludge drying, and specifically discloses a sludge dryer paddle with double-side enhanced heat transfer, which comprises a dryer rotating shaft and a paddle body arranged on the dryer rotating shaft, wherein the paddle body is provided with a paddle inner cavity, the paddle inner cavity is communicated with the inner cavity of the dryer rotating shaft, the left outer wall and / or the right outer wall of the paddle body is provided with a plurality of protrusions, and the left inner wall and / or the right inner wall of the paddle inner cavity is provided with a hydrophobic coating. Compared with the prior art, the unique design of arranging protrusions on the outer side wall surface and arranging a hydrophobic coating on the inner side wall surface can respectively enhance the heat transfer performance of the sludge side and the steam side, overcome the shortcoming of low drying efficiency of the traditional paddle dryer, and effectively improve the overall drying efficiency of the sludge dryer.

Description

Technical Field

[0001] The invention belongs to the technical field of sludge drying, and in particular relates to a sludge drying machine blade with double-sided enhanced heat transfer. Background Art

[0002] With the development of my country's national economy and the acceleration of urbanization, the amount of municipal sludge discharged is increasing. Stable, efficient, and harmless sludge treatment technology is key to ensuring environmental safety and the health of residents. Sludge drying is a key step in sludge treatment. Domestic sludge drying technology started relatively late, so the development of efficient and energy-saving sludge drying equipment is of great significance.

[0003] Paddle dryers are one of the most widely used and mature sludge drying equipment due to their low energy consumption, low system cost, simple structure, and strong adaptability. The main structure of a paddle dryer consists of a jacketed shell, a hollow low-speed rotating shaft, and several hollow paddles welded to the shaft. A heat medium such as steam or thermal oil can be introduced into both the jacket and the hollow paddles, providing inter-wall heating for the sludge inside the dryer. This reduces the moisture content of the sludge outside the paddles and jacket, ultimately drying the sludge.

[0004] Although paddle dryers are widely used, the drying effect of existing designs remains suboptimal. Improving the drying efficiency of paddle dryers is crucial for addressing environmental challenges in sludge treatment. Research has shown that using enhanced heat transfer technology to improve the heat transfer capacity on both sides of the dryer blades can increase evaporation of sludge water, thereby improving the drying efficiency of paddle dryers. Due to significant differences in operating conditions and the physical properties of the media on either side of the dryer blade, the application of enhanced heat transfer technology requires targeted application. For example, on the outer side of the blade, sludge has higher viscosity and is more susceptible to corrosion and erosion. Therefore, enhanced heat transfer on this side must address issues such as sludge adhesion and wear. On the inner side of the blade, steam is used as the working medium, where the flow rate is lower and the working environment is clean and stable. This makes it feasible to apply advanced enhanced heat transfer technologies, not yet widely used in traditional heat exchangers, to the inner side of the blade. Taking into account the characteristics of both sides of the dryer blade and to improve the drying efficiency of paddle dryers, this paper designs a sludge dryer blade structure with enhanced heat transfer on both sides for dryers using steam as the heat medium. Summary of the Invention

[0005] In order to make up for the deficiencies of the prior art, the present invention provides a technical solution for sludge dryer blades with enhanced heat transfer on both sides.

[0006] A sludge dryer blade with double-sided enhanced heat transfer includes a dryer shaft and a blade body arranged on the dryer shaft, the blade body having a blade inner cavity, the blade inner cavity being connected to the inner cavity of the dryer shaft, a plurality of protrusions being provided on the left outer wall and / or the right outer wall of the blade body, and a hydrophobic coating being provided on the left inner wall and / or the right inner wall of the blade inner cavity.

[0007] Furthermore, the left and right outer walls of the blade body are respectively covered with protrusions; and the left and right inner walls of the blade cavity are respectively provided with a hydrophobic coating.

[0008] Furthermore, the protrusion is one or more of a hemispherical structure, a rectangular parallelepiped structure, and a cylindrical structure.

[0009] Furthermore, a drainage baffle is provided in the inner cavity of the blade. The drainage baffle is provided at the rear end of the bottom of the inner cavity of the blade and is laid along the bottom of the inner cavity of the blade toward the top of the inner cavity of the blade.

[0010] Furthermore, the bottom of the drainage baffle is connected to the bottom inner wall of the blade cavity, the top of the drainage baffle and the top inner wall of the blade cavity form a flow opening, and the left and right sides of the drainage baffle are respectively connected to the left and right inner walls of the blade cavity.

[0011] Furthermore, the blade body includes two left and right side panels, an outer sealing plate and a rear end sealing plate. The two side panels are arranged at an angle relative to each other. The front ends of the two side panels are connected, and the rear ends are connected through the rear end sealing plate. The tops of the two side panels are connected through the outer sealing plate, and the bottoms of the two side panels are connected to the dryer shaft.

[0012] Furthermore, the distance between the two side panels gradually increases from bottom to top, and also gradually increases from front to back.

[0013] Furthermore, the side panels are of a fan-ring structure; the front ends of the two side panels together form a blade-shaped structure.

[0014] Furthermore, the width of the outer sealing plate gradually increases from front to back; and the width of the rear end sealing plate gradually increases from bottom to top.

[0015] Furthermore, a communication pipe is provided in the inner cavity of the dryer shaft, and the communication pipe is used to connect the inner cavity of the blade with the cavity of the dryer shaft.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention provides a new paddle dryer with enhanced heat transfer on both sides. The unique design of arranging protrusions on the outer wall and a hydrophobic coating on the inner wall can specifically enhance the heat transfer performance on the sludge side and the steam side respectively, overcoming the shortcoming of low drying efficiency of traditional paddle dryers and effectively improving the overall drying efficiency of the sludge dryer.

[0018] The present invention provides a novel paddle-type sludge dryer blade that is easy to process, flexible in size, and can be mass-produced, and is suitable for existing dryer designs. The blade is processed by assembling multiple components with relatively regular shapes, and each component can be mass-processed. The protrusions for enhancing heat transfer on the sludge side and the hydrophobic coating for enhancing heat transfer on the steam side have a simple and stable structure, low difficulty in mass production, and flexible size. The novel blade provided by the present invention can directly replace the existing traditional dryer blade without changing the overall structural design of the dryer.

[0019] In summary, the present invention overcomes the technical difficulties of low overall drying efficiency and difficulty in improving drying efficiency of existing paddle dryers. Without changing the structural design and rated working fluid parameters of the existing paddle dryer, a new paddle design is proposed that can simultaneously improve the heat transfer capacity of the sludge side and the steam side and the overall drying efficiency of the dryer. The paddle has the advantages of simple structure, flexible size, mass production, and strong versatility. It provides technical support for improving the drying efficiency of existing paddle dryers and has important engineering practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the main schematic diagram of the external structure of the present invention;

[0021] Figure 2 Schematic diagram of the internal structure of the present invention;

[0022] Figure 3 Schematic diagram of the raised structure of the outer wall of the side panel in the present invention.

[0023] In the figure: 1-side plate, 100-protrusion, 101-hydrophobic coating, 2-external sealing plate, 3-rear end sealing plate, 4-dryer shaft, 5-connecting pipe, 6-drainage baffle. DETAILED DESCRIPTION

[0024] In the description of the present invention, it should be understood that the terms "top," "bottom," "outside," "inside," "front," "back," "left," "right," and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. The term "top" refers to the end of the paddle body away from the dryer shaft, and the term "bottom" refers to the end of the paddle body closer to the dryer shaft.

[0025] The present invention will be further described below with reference to the accompanying drawings.

[0026] See also Figure 1-3 A sludge dryer blade with double-sided enhanced heat transfer includes a dryer shaft 4 and a blade body installed on the outer wall of the dryer shaft 4. The number and size of the blade body can be selected according to actual needs. The blade body has a blade inner cavity. Several holes are opened on the wall surface connecting the dryer shaft 4 and the blade inner cavity, and a connecting pipe 5 is installed. The connecting pipe 5 connects the blade body cavity with the inner cavity of the dryer shaft 4.

[0027] Continue reading Figure 1 and Figure 2 The blade body includes two left and right side panels 1, an outer sealing panel 2 and a rear end sealing panel 3. The side panel 1 is a metal plate with a projected shape of a fan ring structure. The front ends of the two side panels 1 are processed with a slope surface at a certain angle, which is welded after splicing to form a knife-shaped end face, so as to better cut the sludge during rotation. The rear end of the side panel 1 is welded to the edge of the rear end sealing panel 3, the bottom is welded to the outer wall of the dryer shaft 4 of the sludge dryer, and the top is welded to the edge of the outer sealing panel 2. The two side panels 1 are arranged relative to each other at a certain angle to form an internal cavity with a gradient structure of narrow bottom and wide top, narrow front end and wide rear end for steam flow. The knife-shaped end face at the front end has the function of cutting the sludge during rotation. The outer sealing panel 2 is an arc-shaped metal plate whose width gradually increases from front to back, and its projected shape is approximately a triangle. The rear end sealing plate 3 is a trapezoidal metal plate, the width of which gradually increases from bottom to top. The bottom is welded to the outer wall of the dryer shaft 4 of the sludge dryer, the top is welded to the edge of the outer sealing plate 2, and the left and right sides are welded to the two side plates 1, finally forming a closed blade cavity inside the blade body to completely separate the sludge from the steam.

[0028] Continue reading Figure 1-3 The outer wall of the side plate 1 is in contact with the sludge to achieve drying. The outer wall is arranged with a certain number and size of protrusions 100 by machining or welding. The preferred structure of the hemispherical protrusion 100 is as follows: Figure 3As shown, a hemispherical structure is adopted. In addition, it can also be set as a rectangular parallelepiped structure, a cylindrical structure, etc. The protrusion 100 can significantly increase the contact area between the dirt and the outer wall, thereby improving the heat transfer. At the same time, the wall surface of the protrusion 100 helps to avoid the large-area wall crusting formed by the excessive gradient of the sludge moisture content, so that the dry sludge is separated from the wall as soon as possible, indirectly improving the heat transfer performance of the outer wall of the side plate 1. The inner wall surface of the side plate 1 is in contact with high-temperature steam with a very low flow rate, providing heat to the sludge side through condensation heat transfer. The inner wall surface is prepared into a micro-nano structure by chemical corrosion, electrochemical deposition, anodization, etc., and then modified with low-surface-energy organic materials to form a hydrophobic coating 101 of a certain thickness. Low-surface-energy materials such as organic polymers, polyethylene, polypropylene, etc. The hydrophobic coating 101 can transform the film condensation on the inner wall of the side plate 1 into beaded condensation, thereby significantly improving the heat transfer coefficient of the inner wall surface of the side plate 1 and accelerating the detachment of droplets. The design requirements can be met as long as the contact angle of the hydrophobic coating 101 is less than 90°, and there is no need to excessively pursue an excessively small contact angle.

[0029] Continue reading Figure 2 The drainage baffle 6 is a trapezoidal metal plate, which is arranged in the area near the bottom rear end inside the blade body. It is arranged radially, that is, in the direction from the bottom to the top, and its length is 1 / 4-1 / 2 of the width of the fan ring of the side plate 1 to form a flow opening with the top of the blade inner cavity. Its bottom is welded to the outer wall of the dryer shaft 4 of the sludge dryer, and the left and right sides are welded to the two side plates 1. Its function is to cooperate with the rotation of the dryer shaft 4 to collect and constrain the condensate at the bottom rear end of the blade body to ensure that the condensate is discharged in time.

[0030] Continue reading Figure 1 and Figure 2 The connecting pipe 5 is a metal circular tube of a certain length, welded to the dryer shaft 4, connecting the paddle cavity with the internal cavity of the dryer shaft 4. During the rotation of the dryer shaft 4, when the paddle body is in the upper position, the condensate accumulated at the bottom is discharged from the paddle body through the connecting pipe 5 and enters the dryer shaft 4. When the paddle body is in the other positions, steam enters the paddle body through the connecting pipe 5 to replenish the condensed steam.

[0031] Optionally, the side panels 1, outer sealing panels 2, rear end sealing panels 3, dryer shaft 4, connecting pipes 5, and drainage baffles 6 together constitute the main structure of this embodiment, and are made of metals such as cast iron, carbon steel, and stainless steel. Other metal materials can also be selected according to actual conditions.

[0032] The manufacturing process of this embodiment is as follows:

[0033] According to the design size, the side plate 1, the outer sealing plate 2, the rear end sealing plate 3, the communication pipeline 5 and the drainage baffle 6 are sequentially machined by machining, and welding positions are reserved at edges of the components, and the drying machine rotating shaft 4 is prepared for installation.

[0034] According to the design size, a plurality of protrusions 100 with certain size and arrangement interval are machined or installed on the outer wall surface of the side plate 1 by machining or welding, and the size of the protrusions 100 is constant or variable.

[0035] According to the design size, a hydrophobic coating 101 with certain size is machined on the inner wall surface of the side plate 1 by chemical corrosion, electrochemical deposition, anodic oxidation or the like, and the thickness of the coating is constant or variable.

[0036] The installation positions of the paddle bodies are determined at the specified positions of the drying machine rotating shaft 4, and three communication holes are machined at the positions, and three communication pipelines 5 are sequentially installed and welded at the communication holes.

[0037] The front end faces of the two side plates 1 with double-side reinforced heat transfer are aligned and welded.

[0038] The drainage baffle 6 is welded at the specified assembly positions of the two side plates 1.

[0039] The outer sealing plate 2 is welded with the top positions of the two side plates 1.

[0040] The rear end sealing plate 3 is welded with the rear end positions of the two side plates 1 to jointly form a paddle main body structure.

[0041] The paddle main body structure welded above is matched with the specified positions of the drying machine rotating shaft 4 and welded to complete the connection of the paddle main body and the drying machine rotating shaft and the sealing of the internal cavity.

[0042] The assembly and welding quality is checked, and the welding slag is cleaned.

[0043] The paddle drying machine of the embodiment overcomes the technical problems that the drying efficiency of the existing paddle drying machine is not high and the efficiency is difficult to improve, and under the premise that the overall structure of the drying machine and the rotating shaft is not changed, a new paddle capable of simultaneously reinforcing the double-side heat transfer capacity and the overall efficiency of the drying machine is provided, the paddle has simple structure, small batch processing difficulty and strong universality, and technical support is provided for improving the drying efficiency of the existing paddle drying machine.

[0044] It should be noted that the protrusions 100 in the application are not completely limited to the standard hemispherical shape, and when the size or shape of the protrusions 100 is changed, it should be covered within the protection scope of the application. Similarly, the drainage baffle 6 is not limited to being arranged in the direction from the bottom to the top of the fan ring structure, and when the drainage baffle 6 is changed to a state close thereto, it should be covered within the protection scope of the application.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A sludge dryer blade with enhanced heat transfer on both sides, comprising a dryer shaft (4) and a blade body arranged on the dryer shaft (4), wherein the blade body has a blade inner cavity, and the blade inner cavity is communicated with the inner cavity of the dryer shaft (4), characterized in that: A plurality of protrusions (100) are provided on the left outer wall and / or the right outer wall of the blade body, and a hydrophobic coating (101) is provided on the left inner wall and / or the right inner wall of the blade cavity; The blade body comprises two left and right side panels (1), an outer sealing panel (2) and a rear end sealing panel (3); the two side panels (1) are arranged to be inclined relative to each other; the front ends of the two side panels (1) are connected; the rear ends are connected via the rear end sealing panel (3); the tops of the two side panels (1) are connected via the outer sealing panel (2); and the bottoms of the two side panels (1) are connected to the dryer shaft (4); The distance between the two side panels (1) gradually increases from bottom to top and also gradually increases from front to back; The side plates (1) are of a fan-ring structure; the front ends of the two side plates (1) together form a blade-shaped structure; The width of the outer sealing plate (2) gradually increases from front to back; and the width of the rear end sealing plate (3) gradually increases from bottom to top.

2. The double-sided heat transfer enhanced sludge dryer blade according to claim 1, characterized in that: The protrusion (100) is one or more of a hemispherical structure, a rectangular parallelepiped structure, and a cylindrical structure.

3. The double-sided heat transfer enhanced sludge dryer blade according to claim 1, characterized in that: A drainage baffle (6) is provided in the blade inner cavity, and the drainage baffle (6) is provided at the rear end of the bottom of the blade inner cavity and is laid along the bottom of the blade inner cavity toward the top of the blade inner cavity.

4. The double-sided heat transfer enhanced sludge dryer blade according to claim 3, characterized in that: The bottom of the drainage baffle (6) is connected to the bottom inner wall of the blade cavity, the top of the drainage baffle (6) and the top inner wall of the blade cavity form a flow opening, and the left and right sides of the drainage baffle (6) are respectively connected to the left and right inner walls of the blade cavity.

5. The double-sided heat transfer enhanced sludge dryer blade according to claim 1, characterized in that: A communication pipe (5) is provided in the inner cavity of the dryer rotating shaft (4), and the communication pipe (5) is used to connect the inner cavity of the blade with the cavity of the dryer rotating shaft (4).

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