Pneumatic conveying short-radius elbow structure

Abstract

The utility model belongs to the technical field of fluid pipe fittings, and particularly relates to a pneumatic conveying short-radius elbow structure, which is formed by sequentially connecting a first pipe joint, an elbow joint and a second pipe joint, and is characterized in that the first pipe joint and the second pipe joint are both variable-diameter pipe bodies with large ends and small ends, and small-diameter pipe orifices are connected with the elbow joint; a lining is arranged in the bent joint and is of a smooth pipe body structure, the inner diameter of the lining is continuously variable in cross section, the two ends of the lining are reduced towards the middle section along the axis, the diameter r of the middle portion is the smallest, and the eccentric distance a which is 5-10 mm and deviates towards the small-diameter direction is formed between the lining and the axis of an inlet. The bent joint is connected with the first pipe joint and the second pipe joint through flanges or welding. Compared with the prior art, the ceramic elbow has the advantages that the lining layer of the elbow joint is formed by sintering ceramic materials, the ceramic materials have the advantages of being high in hardness, good in abrasion resistance, high in chemical stability and the like, scouring and impacting of fluid and particle materials can be effectively resisted, the service life of the elbow is prolonged, and the problem of local excessive abrasion is solved.

Description

Technical Field

[0001] This utility model belongs to the field of fluid pipe fittings technology, and in particular relates to a short-radius elbow structure for pneumatic conveying. Background Technology

[0002] Piping systems are widely used in various fluid transport processes. Elbows, as key components in piping systems that change the direction of fluid flow, are subject to wear and tear over long-term use due to factors such as scouring by high-speed fluids and impacts from particulate matter. Most abrasive perforation caused by particles does not occur in the straight pipe sections but rather on the inner wall of the elbow. Elbows are highly susceptible to wear, and particle groups moving through the elbow can cause this wear. Figure 4 As shown, because the density of particulate matter is much greater than that of gas, the centrifugal force of solid particles in motion is much greater than that of gaseous media. This causes the particle group to separate from the gas at the bend, colliding with a region outside the bend channel in the form of a jet. When the average flow velocity of the material transported in the pipeline is 15-20 m / s, the abrasion of the pipe wall by the material flow at the right-angle bend is 30-40 times greater than that in the horizontal section. Under this severe test, the local pipeline is severely eroded, forming erosion grooves. The bend after long-term wear will not only reduce the conveying efficiency of the pipeline system, but may also lead to pipeline leakage, causing safety accidents, increasing maintenance costs and production interruption time.

[0003] Commonly used elbow types include long-radius elbows, short-radius elbows, and T-shaped pipes with one end closed. The structure of long-radius elbows results in violent impacts between the material and the pipe wall. Furthermore, the larger the elbow radius, the more wear points are created, leading to greater energy loss. T-shaped pipes with one end closed offer advantages such as smaller bend size, easier pipe layout, significantly improved wear resistance, and energy saving. However, they are prone to clogging when conveying viscous materials that easily absorb water and clump. Short-radius elbows combine the advantages of the two types, better meeting the requirements of low wear, low energy loss, and conveying large particles. Short-radius elbows are available in 90°, 60°, and 45° angles. The larger the D / d value, the more impact erosion points are created. Figure 5 As shown, the shaded area represents the abrasion under different values.

[0004] Existing methods in the industry address elbow wear, such as manufacturing elbows with wear-resistant materials, but these are costly; or periodically replacing worn elbows, which is complex and wasteful of resources. Therefore, there is a need for an improved structure that can effectively reduce elbow wear, extend elbow service life, and is cost-effective. Utility Model Content

[0005] The purpose of this utility model is to provide a pneumatic conveying short-radius elbow structure, which overcomes the shortcomings of the existing technology, upgrades and redesigns the existing short-radius elbow structure, optimizes the structure, enhances the wear resistance of the elbow, extends its service life, reduces maintenance costs, and makes it suitable for the pneumatic conveying needs of granular materials in the fields of building materials, chemical raw materials, food raw materials, and pharmaceutical raw materials.

[0006] To achieve the above objectives, this utility model employs the following technical solution:

[0007] A pneumatic conveying short-radius elbow structure includes a first pipe section, an elbow, and a second pipe section connected sequentially. Both the first and second pipe sections are variable-diameter pipes with one end larger than the other, and the smaller diameter inlet is connected to the elbow. The elbow has an inner liner, which is a smooth pipe structure with a continuously variable inner diameter. The inner liner narrows at both ends along the axis towards the middle, with the smallest diameter r at the middle and an eccentricity a = 5-10 mm from the axis at the inlet towards the smaller diameter. The elbow is connected to the first and second pipe sections by flanges or welding.

[0008] Furthermore, in the first and second pipe sections, at least one minor diameter d1: major diameter d = 1:1.2-2.

[0009] Furthermore, the bending radius of the bend is R = (0.8 - 0.85)d.

[0010] Furthermore, the liner is a layer of ceramic, rubber, plastic or metal material.

[0011] Furthermore, the diameter r at the reduced diameter is 80%-90% of the inlet pipe diameter d1 of the bend.

[0012] Furthermore, a narrowed annular band is formed at the center of the bend axis, and the length of the annular band is e = 0.1-0.2r.

[0013] Furthermore, the liner is a prefabricated component, which is mechanically pressed into the bend by applying adhesive; or it is manufactured on the inner wall of the bend by sintering, vulcanization, injection molding, or metal additive manufacturing.

[0014] Compared with the prior art, the beneficial effects of this utility model are:

[0015] 1) The inner lining of the elbow is made of sintered ceramic material. Ceramic has the advantages of high hardness, good wear resistance and strong chemical stability, which can effectively resist the scouring and impact of fluid and particulate materials and extend the service life of the elbow.

[0016] 2) The irregular internal structure of the elbow can guide the fluid to flow along the center of the pipe diameter by changing the shape of the flow channel and the fluid path, preventing the fluid from deviating, and can also compensate for the effect of centrifugal force, so that the particles are all concentrated in the center of the pipe path.

[0017] 3) The reduced diameter structure can prevent impurities in the fluid from settling and adhering, promote fluid turbulence, and reduce the possibility of pipe blockage. It is especially suitable for conveying fluids containing impurities such as sewage and rainwater. Inside the bend, the reduced diameter can buffer particulate matter and reduce the problem of excessive local wear. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of this utility model;

[0019] Figure 2 This is a schematic diagram of the structure of Embodiment 2 of this utility model;

[0020] Figure 3 This is a schematic diagram of the fluid turbulence structure in Embodiment 2 of this utility model;

[0021] Figure 4 This is a schematic diagram of the movement trajectory of a particle group through a bend in the prior art;

[0022] Figure 5 This is a comparative diagram of erosion conditions under different D / d values ​​in existing technologies;

[0023] In the diagram: 1-first pipe section, 2-bend, 3-lining, 4-second pipe section, 5-ring. Detailed Implementation

[0024] The technical solution of this utility model will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are some embodiments of this utility model, but not all embodiments.

[0025] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the specific embodiments used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the specific embodiments described below are some embodiments of this utility model. For those skilled in the art, other specific embodiments can be obtained based on these specific embodiments without creative effort.

[0026] The components of the present invention described and shown in the specific embodiments herein can be arranged and designed in numerous different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the specific embodiments is not intended to limit the scope of the claimed invention, but only to illustrate selected embodiments of the invention.

[0027] See Figure 1This is a schematic diagram of a pneumatic conveying short-radius elbow structure according to an embodiment of the present invention. It includes a first pipe section 1, an elbow 2, and a second pipe section 4 connected in sequence. Both the first pipe section 1 and the second pipe section 4 are variable-diameter pipes with one end larger than the other. The smaller diameter pipe opening is connected to the elbow 2. The elbow 2 is provided with an inner liner 3. The inner liner 3 is a smooth pipe structure with a continuously variable cross-section of the inner diameter. The diameter of the inner liner 3 decreases from the two ends along the axis towards the middle section. The diameter r at the middle section is the smallest and forms an eccentricity a = 5-10 mm with the axis at the inlet towards the smaller diameter. The inner wall of the inner liner is smooth and rounded. The two ends of the elbow 2 are connected to the first pipe section 1 and the second pipe section 4 by flanges or welding.

[0028] In the first pipe section 1 and the second pipe section 4, at least one small diameter d1:large diameter d = 1:1.2-2, with a preferred value of 1:1.5. The linear and continuous change of the inner diameter of the pipe section allows for linear flow regulation. According to the continuity equation, when the flow rate is constant, a change in the pipe diameter at the bend will correspondingly change the flow velocity. When the fluid flows from the large diameter end to the small diameter end, the cross-sectional area decreases, and the flow velocity increases, which can, to some extent, prevent material deposition. The bending radius R of bend 2 is 0.8-0.85d, with a preferred value of R = 0.83d. After modification, bend 2 has sufficient thickness to maintain its strength and rigidity. The size of the bending radius R of bend 2 has a significant impact on the resistance, abrasion, and stability when fluid or material passes through. A larger bending radius reduces resistance and wear but increases space occupation, while a smaller bending radius increases resistance and wear but saves space. The interior of the liner 3 adopts a smooth transition arc design, facilitating processing, manufacturing, and molding.

[0029] The inner liner 3 features a necking structure in the middle, with the diameter r at the necking point being 80%-90% of the inlet pipe diameter d1 of the bend, preferably 85% d. By reducing the pipe diameter, the airflow velocity is increased, enhancing the material carrying capacity and preventing material deposition. Simultaneously, an eccentricity a = 5-10 mm is designed in the middle of the inner liner 3, not only to compensate for centrifugal force but also to increase the liner thickness and improve its resistance to erosion and wear.

[0030] The inner liner 3 can be made of ceramic, rubber, plastic, or metal. It is manufactured on the inner wall of the bend 2 through sintering, vulcanization, injection molding, or metal additive manufacturing. The material selection depends on the particle size and hardness of the conveyed material. Ceramic materials, such as alumina ceramic, silicon carbide ceramic, and zirconia ceramic, are preferred. The inner liner 3 is a prefabricated component and can be mechanically installed into the bend 2, which consists of two separate parts. However, an adhesive or similar substance needs to be applied to the inside of the bend 2 before installation. Ceramic inner liners 3 are suitable for conveying materials with a Mohs hardness of less than 10.

[0031] See Figure 2-3This is a schematic diagram of a pneumatic conveying short-radius elbow structure according to a second embodiment of this utility model. A narrowed annular band 5 is formed at the center of the axis of the elbow 2, with a length e = 0.1-0.2r. The arrows indicate the material flow direction. The annular band 5 at the necking point between the outlet inner wall of the first pipe section 1 and the inner lining 3 is connected by an arc design, forming a P-region. This buffers the incoming material. Furthermore, the pipe diameter in the P-region continuously changes, decreasing in size. According to the continuity equation A1v1 = A2v2 (where A is the cross-sectional area of ​​the pipe and v is the flow velocity), the flow velocity changes accordingly when the pipe diameter changes. For example, when the pipe diameter decreases at the necking point, the cross-sectional area decreases, and the flow velocity increases. From the moment the material enters the P-region, the material velocity gradually increases, and the material bounces off the side wall of the inner lining 3, causing airflow disturbance in the P-region. This effectively disperses any potential material accumulation, maintaining the material in a good suspended state, allowing it to smoothly pass through the elbow with the airflow and reducing the risk of blockage. When passing through the ring zone 5, the material velocity is the highest. After a certain degree of brief turbulence, the material enters the Q zone. The Q zone and the P zone are symmetrical structures. The pipe diameter also changes in the Q zone, gradually increasing. According to the continuity equation, the velocity decreases and the pressure increases, returning to the straight pipe flow state.

[0032] Because the pipe diameter changes continuously within the liner 3, the material flow rate and pressure are regulated, which can prevent impurities in the fluid from settling and adhering, reduce the possibility of pipe blockage, improve the material conveying condition, and increase conveying efficiency.

[0033] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A pneumatic conveying short radius elbow structure comprising a first pipe section, an elbow section and a second pipe section connected in sequence, characterized in that, The first pipe section and the second pipe section are both variable-diameter pipe bodies with one large end and one small end, wherein the small-diameter pipe openings are connected with the bend section; the bend section is provided with an inner liner, the inner liner is a smooth pipe body structure, the inner diameter is continuously variable cross-section, the two ends of the inner liner are reduced in diameter along the axis to the middle section, the diameter r is smallest at the middle and forms an eccentricity a of 5-10 mm in the small-diameter direction with the axis at the inlet; the bend section is connected with the first pipe section and the second pipe section through flanges or welding.

2. A short radius elbow structure for pneumatic conveying according to claim 1, characterized in that At least one of the first pipe section and the second pipe section has a small-diameter d1: large-diameter d = 1:1.2-2.

3. A short radius elbow structure for pneumatic conveying according to claim 1, wherein The bend section has a bending radius R = (0.8-0.85)d.

4. A short radius elbow structure for pneumatic conveying according to claim 1, wherein The inner liner is a layer of ceramic, rubber, plastic or metal material.

5. A short radius elbow structure for pneumatic conveying according to claim 1, wherein The diameter r at the reduced-diameter section is 80%-90% of the inlet pipe diameter d1 of the bend section.

6. A short radius elbow structure for pneumatic conveying according to claim 1, wherein The axis of the bend section forms a reduced-diameter ring band at the middle, the length of the ring band is e = 0.1-0.2r.

7. A short radius elbow structure for pneumatic conveying according to claim 1, wherein The inner liner is a prefabricated part, which is installed in the bend section by mechanical pressing and gluing, or is formed on the inner wall of the bend section by sintering, vulcanization, injection molding or metal additive manufacturing.

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