Lightweight tee

Abstract

The utility model discloses a kind of lightweight three-way pipe fittings, relate to fluid conveying equipment technical field, for the connection of pipeline system. It mainly includes main pipeline, branch pipeline, reinforcing rib and circular opening. Four trapezoidal reinforcing ribs are evenly arranged in the circumferential direction of the outer wall of the pipeline, and the main pipeline and the branch pipeline are connected vertically to guide the force flow transmission in a streamline configuration. The main body adopts a fish belly-shaped main pipeline and a horn-shaped branch pipe opening, which simultaneously increases the bending stiffness and reduces the weight of the pipe fitting. The eccentric inner passage and the enlarged step are introduced innovatively to reduce the non-uniformity of the internal pressure of the pipeline and improve the sealing performance at the joint. The integrated molding process with silica sol prolongs the hydraulic cycle life, reduces the comprehensive cost under the same pressure-bearing capacity, and finally realizes the improvement of lightweight and high-strength pipe fittings.

Description

Technical Field

[0001] This utility model relates to the field of fluid transport equipment technology, and specifically to a lightweight tee fitting for connecting pipeline systems. Background Technology

[0002] Traditional reducing tees, due to their uniform wall thickness distribution, are prone to stress concentration at branch joints under high-pressure conditions, leading to ruptures or even pipe bursts. In current technology, to meet higher pressure standards, the industry typically adopts a method of increasing the wall thickness throughout the fitting, resulting in a 30%-40% increase in weight (e.g., a DN50 tee fitting increases from 0.9 kg to 1.3 kg). This not only raises raw material costs but also causes an imbalance in the pipeline system load during installation. Furthermore, uneven pressure distribution caused by differences in wall thickness between the fitting and the pipe at the socket further exacerbates the risk of localized failure.

[0003] Publication patent CN221121398U improves the strength and sealing of pipe fittings by setting a saddle-shaped connector. Similar to most pipe fitting patent optimization methods, it adds a structure to increase the strength of the original tee fitting. However, due to the addition of extra components, there are often problems such as increased weight and insufficient stress concentration relief. Therefore, there is an urgent need for a tee fitting that combines high pressure resistance with lightweight characteristics. Utility Model Content

[0004] This invention provides a lightweight tee fitting. By incorporating trapezoidal ribs on the sidewalls, the force transmission path on the sidewalls is optimized. Simultaneously, the fish-belly shaped pipe body and flared nozzle reduce stress concentration at the branch pipe ends, rationally distribute wall thickness, and avoid a surge in weight and material waste, thus achieving a lightweight tee fitting, increasing its strength, and extending its service life. Furthermore, the eccentric design and increased step at the joint solve the problem of localized stress surges caused by wall thickness differences after insertion, further improving the fitting's sealing performance.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a lightweight tee fitting, comprising a main pipe 1 which is a straight circular pipe, with a circular opening 4 on the side of the middle of the pipe; a branch pipe 2 is provided on the circular opening, the axis of the branch pipe 2 being perpendicular to the main pipe 1; four reinforcing ribs 3 are vertically arranged on the outer wall of the connection between the main pipe 1 and the branch pipe 2, distributed at 90° intervals around the perimeter, and two reinforcing ribs 3 are provided on each side of the pipe, and are symmetrically arranged on the outer wall at a quarter position with respect to the axis of the branch pipe 2.

[0006] Preferably, the reinforcing rib 3 is vertically installed on the outer wall of the pipe connection, connecting the main pipe 1 and the branch pipe 2 above and below the circular opening 4; the upper end of the reinforcing rib 3 starts slightly higher than the circular opening, and the lower end extends to the horizontal plane of the axis of the main pipe 1. By setting the reinforcing rib, the strength of the stress concentration point on the side wall of the pipe fitting can be strengthened, and the circumferential deformation of the connection can be suppressed.

[0007] Preferably, the reinforcing rib 3 is a trapezoidal rib plate, with the upper trapezoidal hypotenuse of the reinforcing rib 3 perpendicular to the branch pipe 2 and the lower trapezoidal hypotenuse tangent to the main pipe 1 and perpendicular to the horizontal plane. This structure can optimize the force flow transmission path on the side wall of the pipe fitting and improve local strength.

[0008] Preferably, the main pipe 1 has a large cross-section in the middle, gradually decreasing towards both ends to form a fish-belly structure. This structure has been used in building materials to increase the bending stiffness of the main structure, reduce weight compared to pipes with the same wall thickness, and save materials.

[0009] Preferably, the wall thickness of branch pipe 2 near the circular opening 4 is greater than that further away from the connection, forming a trumpet-shaped gradual transition structure. The outer wall design, which is thinner at the top and wider at the bottom, can reasonably distribute the wall thickness to the pipe connection where it bears greater pressure, thereby avoiding the risk of failure due to excessive burst pressure at the branch pipe opening.

[0010] As a preferred option, the inner side of the circular opening 4 at the connection between the main pipe 1 and the branch pipe 2 is chamfered with a radius of 2mm and an angle of 45° to eliminate stress concentration at the sharp corner of the pipe connection and reduce the stress concentration factor.

[0011] Preferably, the axis 14 of the main pipe 1 at the joint is located 1.8mm-1.9mm above the axis 15 of the inner pipe. The eccentric design avoids overall thickness increase, reduces material costs, and improves the stress distribution uniformity at the joint.

[0012] As a preferred option, both the main pipe socket 12 and the branch pipe socket 22 are provided with enlarged steps 16 to compensate for the difference in pipe wall thickness at the socket after the pipe is inserted, balance the distribution of liquid pressure inside the pipe, and increase installation compatibility.

[0013] As a preferred option, increasing the height of step 16 to match the wall thickness of the inserted pipe will make the socket sealing pressure uniform, enhance the sealing performance, and alleviate stress concentration.

[0014] As a preferred option, the main pipe 1 and the branch pipe 2 are integrally formed, thereby eliminating weak areas in the weld, improving overall strength, and increasing hydraulic cycle life by 3 times.

[0015] Beneficial effects: This utility model guides the force flow path on the side wall of the pipe fitting by setting a special trapezoidal rib plate, and at the same time adopts a fish belly-shaped pipe body and a trumpet-shaped pipe opening to reasonably distribute the pipe fitting wall thickness, which effectively improves the strength of the pipe fitting and achieves the lightweighting of the tee fitting; the eccentric design at the joint and the setting of the increased step further solve the problem of uneven liquid pressure inside the pipe and improve the sealing performance of the pipe fitting. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0017] Figure 2 This is a front structural diagram of the present invention.

[0018] Figure 3 This is a side sectional view of the reinforcing rib of this utility model.

[0019] Figure 4 This is a front structural cross-sectional view of the present invention.

[0020] In the diagram: 1-Main pipe, 2-Branch pipe, 3-Reinforcing rib, 4-Circular opening, 11-Main pipe socket channel, 12-Main pipe inner channel, 13-Enlarged step, 21-Branch pipe socket channel. Detailed Implementation

[0021] Lightweight tee fittings are tee fittings with trapezoidal stiffeners on the outer wall. Through pressure testing and analysis, specially designed stiffeners are placed at the points of maximum pressure on the outer wall of the fitting to guide the flow path and enhance the strength of the outer wall, demonstrating unique engineering value in drainage and water supply systems. Traditional tee fittings often require thicker pipe walls and additional external fixing devices to improve hydraulic resistance, which inevitably leads to excessive weight and material waste. Lightweight tee fittings, however, increase the fitting's pressure resistance and achieve a more rational and even distribution of wall thickness by incorporating trapezoidal stiffeners on the outer wall and a fish-belly structure, thus strengthening the fitting while maintaining a lightweight design.

[0022] like Figure 1 , Figure 2 As shown, the main pipe 1 adopts a straight-through circular pipe structure with a circular opening 4 on the side wall at the axial center point of the pipe body. The diameter of the opening matches the inner diameter of the branch pipe 2. The branch pipe 2 connects to the main pipe 1 through this circular opening, and its axis forms a 90° angle with the axis of the main pipe 1, with a tolerance controlled within ±0.5° to avoid additional bending moments caused by eccentric loading. This main pipe 1 and branch pipe 2 are integrally formed using a silica sol precision casting process, eliminating the structural weaknesses caused by the heat-affected zone of traditional welding, improving the overall strength of the pipe fitting, and extending its service life in hydraulic circulation. This basic structure provides a good foundation for subsequent pipe fitting reinforcement and weight reduction.

[0023] like Figure 2As shown, a reinforcing rib 3 is provided on the outer wall of the tee fitting. The reinforcing rib 3 is located at the connection between the main pipe 1 and the branch pipe 2, installed vertically, and simultaneously connects the main pipe 1 and the branch pipe 2. Unlike the commonly used reinforcing rib placement, this placement reflects a profound consideration of mechanical performance. In simulated hydraulic experiments, the sidewall at the pipe fitting connection is where the stress is greatest. The reinforcing rib 3 is symmetrically placed at approximately halfway points on both sides of the axis of the branch pipe 2, and is also symmetrically placed on both sides of the pipe, evenly distributed at 90° circumferentially. When subjected to high-intensity hydraulic pressure, the reinforcing ribs of traditional pipe fittings are placed on the left and right sides of the connection to prevent side leakage, but cannot protect the sidewall at the stress concentration point, relying only on the strength of the material itself for support; while the reinforcing rib of this utility model is placed precisely on the sidewall, simultaneously connecting the main pipe 1 and the branch pipe 2, greatly ensuring the strength of the sidewall and preventing the sidewall from bursting due to excessive hydraulic pressure.

[0024] like Figure 3 As shown, stiffener 3 is a trapezoidal rib with a height 1.2 times the diameter of the branch pipe (approximately 60mm for a DN50 fitting), covering the stress concentration area. It features two parallel sides, one longer and one shorter, designed in a streamlined manner. The longer lower side conforms to the sidewall of the pipe connection. The shorter upper side connects vertically to the branch pipe 2; the longer lower side connects to the main pipe 1 and is perpendicularly tangential to it, forming a continuous force flow transmission path. This rib structure provides vertical tension on the sidewall, guiding the force flow path for the stress applied to the sidewall by the hydraulic environment. This significantly reduces the impact of stress concentration on the pipe wall, substantially improving the pipe wall's strength and load-bearing capacity. Through ANSYS finite element analysis, the peak stress at the branch pipe inlet of a traditional tee reached 285 MPa under a PN2.5 MPa water pressure, while the peak stress dropped to 172 MPa after adding reinforcing ribs, a reduction of 39.6%; the circumferential deformation decreased from 0.38 mm to 0.12 mm, a reduction of 68.4%. This design optimizes the stress flow propagation path, reducing crack propagation rate by 60% in hydraulic pulse fatigue tests and increasing cycle life from 100,000 cycles to over 300,000 cycles.

[0025] like Figure 2 As shown, the external structural design of the main pipe 1 and the branch pipe 2 is another core design of the lightweight tee fitting.

[0026] The main pipe 1 adopts a fish-belly-shaped tapered pipe design, with the pipe cross-sectional diameter gradually decreasing from the middle to both sides. Specifically, the outer diameter of the middle section of the pipe increases to 1.15 times the standard value (57.5mm for DN50 fittings), and linearly decreases to the standard diameter of 50mm towards both ends, while the wall thickness gradually decreases from 4.5mm to 3.2mm, with a gradient slope of 0.065mm / mm. This design primarily draws inspiration from the fish-belly beam principle in civil engineering. In civil construction, the fish-belly crane beam is a type of beam with a large central section that gradually decreases towards both ends, resembling a fish's belly. It's a beam designed to increase bending strength and save materials. This utility model applies this design concept to the main pipe 1. By increasing the moment of inertia of the section in the middle, where the bending moment is greatest, the bending stiffness can be increased by approximately 40%, while also saving materials. It also utilizes the concept of distributing pipe wall thickness. The fish-belly structure thickens the pipe wall in the middle section, where hydraulic strength and stress are highest, while thinning it at the ends where pressure is relatively lower. Ultimately, without changing the overall weight of the pipe, the wall thickness is rationally distributed according to stress distribution, thereby improving the pipe's strength. Compared with traditional pipe fittings of equal wall thickness, under the same pressure bearing capacity of PN2.5MPa, the weight of the pipe fitting is reduced from 1.3kg to 0.94kg, a weight reduction of 27.7%, while the material cost is reduced by 22%. This achieves lightweighting of tee pipe fittings and improves strength and load-bearing capacity.

[0027] The outer wall of branch pipe 2 adopts a flared structure, with the wall thickness near the circular opening 4 being greater than that further away from the connection point, forming a gradually tapering flared shape that opens downwards. Specifically, the wall thickness at the connection end (near the circular opening 4) is 4.8mm, gradually decreasing to 3.0mm after extending 20mm axially. This gradually tapering flared design strengthens the connection between the main pipe 1 and branch pipe 2, similar to the diagonal stiffening plates commonly used in existing technologies, making stress concentration points less prone to breakage. This design concept is similar to the fish-belly structure of the main pipe 1, featuring a non-uniform wall thickness distribution. The wall is thickened at stress-concentrated, easily broken areas, while thinning at lower stress points. This rational distribution of thickness avoids the excessive weight of the tee fittings resulting from uniform thickness. Overly heavy tee fittings can negatively impact normal use, such as making disassembly difficult and increasing the overall load on the piping system, reducing the lifespan of the pipe connections. This non-uniform wall thickness reinforced tee fitting avoids these problems. According to the burst pressure test, the design increases the burst pressure at the branch pipe outlet from 4.2MPa to 6.5MPa, an increase of 54.8%, and the rupture location shifts from the branch pipe outlet to a non-critical area in the middle of the pipe body.

[0028] like Figure 4As shown, a chamfer is provided on the inner side of the circular opening 4 at the connection between the main pipe 1 and the branch pipe 2. The chamfer radius is 2mm, and the chamfer angle is approximately 45 degrees. The chamfer is precision machined by a CNC machine tool, and the surface roughness Ra≤3.2. The original sharp corner design caused a change in flow velocity when the fluid flowed through this area, resulting in stronger stress inside the pipe fitting. After adopting the chamfer, the flow of fluid from the branch pipe 2 into the main pipe 1 is smoother, the flow velocity change is smaller, and the internal stress of the pipe fitting is reduced. According to experiments, the chamfer can eliminate the stress concentration phenomenon at the sharp corner, reducing the crack propagation rate inside the pipe fitting from 7.8μm / 10,000 cycles to 3.1μm / 10,000 cycles, a reduction of 60.3%. Finite element analysis shows that the stress concentration factor at the pipe connection can be reduced from 3.1 to 1.8, and the peak stress is reduced by 42%, resulting in a significant improvement in pipe strength.

[0029] By incorporating trapezoidal stiffeners on the sidewalls and employing a design scheme with uneven wall thickness, the synergistic effect of these two elements achieves enhanced strength in the tee fitting without excessively increasing material thickness. This design results in a lightweight yet high-strength tee fitting. Using this lightweight design, the final tee fitting achieves a thickness increase of 0.5-1.6 mm in areas with stress >150 MPa and a thinning of 0.3-1.0 mm in areas with stress <80 MPa, thereby maximizing material utilization. The overall weight of the fitting is reduced by 28%, saving approximately 22% in material costs, while simultaneously increasing bending stiffness by 35% and nearly tripling its service life.

[0030] like Figure 4 The image shows the side structure of this tee fitting. The main pipe socket channel 11 of this tee fitting adopts an eccentric design; the axes of the two main pipe socket channels 11 on both sides are not aligned with the axis of the central inner channel 12, but are instead located below the axis of the inner pipe. This results in the inner main pipe channel 12 being slightly recessed. Specifically, the axis of the main pipe socket channel 11 is shifted upwards by 1.85 mm compared to the axis of the inner main pipe channel 12. This eccentric socket design works in conjunction with the uneven wall thickness design to adjust the distribution of pipe wall thickness. The main pipe's inner channel 12 slightly subsides, increasing the wall thickness at the pipe connection point above the socket (where stress is concentrated) and decreasing it below, thus achieving a more balanced wall thickness distribution. Secondly, it compensates for the wall thickness difference, offsetting the 1.3mm thickness difference between the inserted pipe (3.2mm) and the fitting (4.5mm). Finally, by compensating for the bottom gap caused by the pipe's gravity, it reconstructs the pressure distribution at the sealing interface, changing the pressure on the sealing ring from unilateral compression to circumferential uniform compression, thereby improving the device's sealing performance. Fluid dynamics simulations show that when the inserted pipe wall thickness δ = 3.2mm, the 1.85mm eccentric design can improve contact stress uniformity by 90%, reducing stress concentration and enhancing the fitting's pressure-bearing capacity.

[0031] like Figure 4 As shown, Figure 4 This is an internal sectional view of the front structure of the pipeline. The utility model features an annular enlarged step 13 at both the main pipeline socket and the branch pipeline socket. The height h of the enlarged step is the same as the wall thickness δ of the inserted pipe (h = 3.2 ± 0.1 mm when δ = 3.2 mm), and the step width w = 5 mm.

[0032] Enlarging the step can limit the insertion of the pipe, making it easier to insert and secure. In existing pipe fitting sockets, without an enlarged step and instead using a uniform internal channel, deformation at the socket is inevitable after the outer pipe is inserted. This increases the reliability of the pipe-fitting connection, but this uncontrollable deformation is usually not uniform, often resulting in excessive deformation on one side of the fitting, affecting its pressure-bearing capacity. This connection method relies excessively on the reliability of the fitting material itself and does not offer a structural solution. Enlarging the step, however, represents a structural optimization.

[0033] Another effect of the enlarged step is that it offsets the wall thickness difference introduced after pipe insertion, resulting in more uniform fluid pressure within the pipe. Without the enlarged step, the wall thickness at the joint is thicker than that of the inner channel after direct pipe insertion. Furthermore, the flow velocity changes due to this wall thickness difference as fluid flows through the joint, leading to greater stress concentration within the pipe. This is especially true at the joint, where it often faces higher flow velocities and greater pressure, increasing the likelihood of pipe breakage. Therefore, the enlarged step was designed to compensate for the wall thickness difference between the joint and the inner pipe. After pipe insertion, the overall wall thickness becomes more uniform, the fluid velocity remains constant, and the overall structure becomes more stable. Combined with the eccentric design, the synergistic effect reduces the interface stress non-uniformity from 63% to 18% and also improves the sealing performance at the joint.

[0034] This embodiment achieves a synergistic optimization of lightweight and high strength in tee fittings through multi-dimensional structural innovation. In the main pipe design, the main pipe adopts a fish-belly-shaped, gradually tapering pipe body with a central bulge, and the wall thickness smoothly transitions from the middle to both ends, drawing inspiration from the bending beam principle in civil engineering to enhance rigidity. The branch pipe outlet innovatively adopts a downward-opening, trumpet-shaped gradually tapering structure, with the wall thickness at the connection gradually thinning along the axial direction. Regarding stress control, four trapezoidal reinforcing ribs are evenly distributed circumferentially on the outer wall. Their unique streamlined configuration, vertically aligned with the branch pipe above and tangentially aligned with the main pipe below, guides the force flow transmission path, reduces stress peaks at the fitting connection, and decreases the circumferential deformation of the fitting's outer wall. In terms of the connection structure, the inner channel of the main pipe adopts a precise eccentric recessed design of approximately 1.85 mm to compensate for differences in pipe wall thickness and thicken the upper stress concentration area; combined with the annular step (with the same height as the pipe wall thickness) added to the socket, the unevenness of interface stress is sharply reduced. In terms of manufacturing process, the one-piece silica sol casting eliminates weak areas in the weld, improving hydraulic cycle life. Ultimately, while maintaining the same pressure resistance, the pipe fittings were successfully reduced in weight, saving material costs, improving bending and pressure resistance, and achieving a balance between lightweight and high pressure resistance.

Claims

1. A lightweight tee fitting, characterized in that, include: The main pipe (1) is a straight circular pipe, and a circular opening (4) is provided on the side part in the middle of the pipe; A branch pipe (2) is provided on the circular opening (4), and the axis of the branch pipe (2) is perpendicular to the main pipe (1); Four reinforcing ribs (3) are vertically arranged on the outer wall at a circumferential interval of 90° at the connection between the main pipe (1) and the branch pipe (2). Two reinforcing ribs (3) are arranged on each side of the pipe and are symmetrically arranged on the outer wall at a quarter position with respect to the axis of the branch pipe (2).

2. A lightweight tee fitting according to claim 1, characterized in that, The reinforcing rib (3) is vertically installed on the outer wall of the pipe connection, connecting the main pipe (1) and branch pipe (2) above and below the circular opening (4); the upper end of the reinforcing rib (3) is slightly higher than the circular opening, and the lower end extends to the horizontal plane of the axis of the main pipe (1).

3. A lightweight tee fitting according to claim 1 or 2, characterized in that, The reinforcing rib (3) is a trapezoidal rib plate. The upper trapezoidal hypotenuse of the reinforcing rib (3) is perpendicular to the branch pipe (2), and the lower trapezoidal hypotenuse is tangent to the main pipe (1) and perpendicular to the horizontal plane.

4. A lightweight tee fitting according to claim 1 or 2, characterized in that, The main pipe (1) has a large cross-section in the middle, which gradually decreases towards both ends of the pipe, forming a fish-belly structure.

5. A lightweight tee fitting according to claim 1 or 2, characterized in that, The wall thickness of the branch pipe (2) near the circular opening (4) is greater than that away from the connection, forming a trumpet-shaped gradual structure.

6. A lightweight tee fitting according to claim 5, characterized in that, The inner side of the circular opening (4) at the connection between the main pipe (1) and the branch pipe (2) is chamfered with a radius of 2mm and an angle of 45°.

7. A lightweight tee fitting according to claim 1 or 2, characterized in that, The axis of the main pipeline connection channel (11) is located 1.8mm-1.9mm above the axis of the main pipeline inner channel (12).

8. A lightweight tee fitting according to claim 1 or 2, characterized in that, Both the main pipe socket and the branch pipe socket are provided with enlarged steps (13).

9. A lightweight tee fitting according to claim 8, characterized in that, Increase the height of the step (13) to match the wall thickness of the inserted pipe.

10. A lightweight tee fitting according to claim 1 or 2, characterized in that, The main pipe (1) and the branch pipe (2) are integrally formed.

Images