A flanged elbow is a pipe fitting that combines a flange and an elbow. It is used to alter the direction of a pipeline, typically by 90 degrees or 45 degrees. The flange portion of this fitting can be bolted to another flanged pipe or fitting, providing a secure and leak-proof connection. This type of fitting is commonly used in piping systems where flow direction needs to be changed while maintaining a robust seal at the joint. Flanged elbows are frequently employed in industries such as pipeline engineering, oil and gas, chemical processing, and water treatment.
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Types of Flanged Elbows
- Single Flanged Elbow
Single Flanged Elbow is a specialized pipe fitting featuring a flange at one end and a socket or pipe opening at the other. This design enables flexible connections between flanged valves, pumps, or equipment and socket-welded piping systems, making it particularly common in water supply, drainage, and fire protection engineering. Its flanged end is secured with bolts, while the other end typically connects via insertion, welding, or rubber gaskets, effectively resolving interface conversion between different pipe types.
Advantages:
Lower cost: Eliminates one flange compared to double-flanged elbows.
Lighter weight: Reduced overall mass.
Fewer leakage points: Welded connections are permanent, offering greater reliability and fewer potential leak points than flanged joints.
Space-saving: Welded connections are more compact than flanged connections at equipment interfaces.
Disadvantages:
Non-removable: Welded ends are permanent; cutting is required for maintenance or replacement, causing significant inconvenience.
High installation requirements: Requires skilled welders for welding operations and quality inspections (e.g., X-ray testing).
- Double Flanged Elbow
Double flanged elbows feature flanges on both ends and are standard components in flanged piping systems. This elbow utilizes flanges, gaskets, and bolts to achieve reliable connections between pipes, offering excellent sealing performance and pressure-bearing capacity. Due to its disassembly capability, the double flanged elbow facilitates maintenance, replacement, or cleaning, making it widely used in industrial piping systems requiring high reliability and ease of maintenance, such as petroleum, chemical, and natural gas sectors.
Advantages:
Easy Installation: Quick connection and disassembly via bolts, facilitating maintenance and replacement.
Good Alignment: Flange connections facilitate pipe alignment.
Standardization: Dimensions and pressure ratings comply with international standards (e.g., ASME B16.9, EN 10253), ensuring high interchangeability.
Disadvantages:
Higher Cost: An additional flange increases material and manufacturing expenses compared to single-flange elbows.
Greater Weight: The extra flange adds significant mass.
Potential Leak Points: An additional flange connection introduces a further potential leakage point.
Material & Grades of Flanges :
Carbon Steel :
ASTM A105 / A105N,ASTM A350 LF2 / LF3, A694 F42 / 46 / 52 / 56 / 65 / 70
Alloy Steel :
ASTM / ASME A/SA 182 & A 387 F1, F5, F9, F11, F12, F22, F91
Stainless Steel :
ASTM A 182, A 240 F 304, 304L, 304H, 316, 316L, 316Ti, 310, 310S, 321, 321H, 317, 347, 347H, 904L
Duplex & Super Duplex Steel :
ASTM / ASME A/SA 182 F 44, F 45, F51, F 53, F 55, F 60, F 61
Copper Alloy Steel :
ASTM SB 61 , SB62 , SB151 , SB152 UNS No. C 70600 (Cu-Ni 90/10), C 71500 (Cu-Ni 70/30), UNS No. C 10100, 10200, 10300, 10800, 12000, 12200
Nickel Alloy :
ASTM SB564, SB160, SB472, SB162 Nickel 200 (UNS No. N02200), Nickel 201 (UNS No. N02201), Monel 400 (UNS No. N04400), Monel 500 (UNS No. N05500), Inconel 800 (UNS No. N08800), Inconel 825 (UNS No. N08825), Inconel 600 (UNS No. N06600), Inconel 625 (UNS No. N06625), Inconel 601 (UNS No. N06601), Hastelloy C 276 (UNS No.N10276), Alloy 20 (UNS No. N08020)
Double Flanged Elbow 90°
| Nominal Size | Outside Diameter at Bevel | Center to End | ||
| 90° Elbows | ||||
| DN | NPS | OD | A | |
| LR | SR | |||
| 15 | 1/2 | 21.3 | 38 | |
| 20 | 3/4 | 26.7 | 38 | |
| 25 | 1 | 33.4 | 38 | 25 |
| 32 | 1 1/4 | 42.2 | 48 | 32 |
| 40 | 1 1/2 | 48.3 | 57 | 38 |
| 50 | 2 | 60.3 | 76 | 51 |
| 65 | 2 1/2 | 73.0 | 95 | 64 |
| 80 | 3 | 88.9 | 114 | 76 |
| 90 | 3 1/2 | 101.6 | 133 | 4、89 |
| 100 | 4 | 114.3 | 152 | 102 |
| 125 | 5 | 141.3 | 190 | 127 |
| 150 | 6 | 168.3 | 229 | 152 |
| 200 | 8 | 219.1 | 305 | 203 |
| 250 | 10 | 273.0 | 381 | 254 |
| 300 | 12 | 323.8 | 457 | 305 |
| 350 | 14 | 355.6 | 533 | 356 |
| 400 | 16 | 406.4 | 610 | 406 |
| 450 | 18 | 457.0 | 686 | 457 |
| 500 | 20 | 508.0 | 762 | 508 |
| 550 | 22 | 559.0 | 838 | 559 |
| 600 | 24 | 610.0 | 914 | 610 |
| 650 | 26 | 660.0 | 991 | 660 |
| 700 | 28 | 711.0 | 1067 | 711 |
| 750 | 30 | 762.0 | 1143 | 762 |
| 800 | 32 | 813.0 | 1219 | 813 |
| 850 | 34 | 864.0 | 1295 | 864 |
| 900 | 36 | 914.0 | 1372 | 914 |
| 950 | 38 | 965.0 | 1448 | 965 |
| 1000 | 40 | 1016.0 | 1524 | 1016 |
| 1050 | 42 | 1067.0 | 1600 | 1067 |
| 1100 | 44 | 1118.0 | 1676 | 1118 |
| 1150 | 46 | 1168.0 | 1753 | 1168 |
| 1200 | 48 | 1219.0 | 1829 | 1219 |
90° Elbow Flanged on Both Sides
Connection Method: Flanged elbows connect pipes using flanges, gaskets, and bolts. This connection method provides excellent sealing, withstands high pressure and temperature, and is easily disassembled for maintenance.
Material: Common materials for flanged elbows include carbon steel, stainless steel, and alloy steel. Different materials suit various media and operating environments.
Bend Angles: The most common flanged elbow angles are 90° and 45°, with 180° and other special angles also available. Different angles accommodate varied pipeline layout requirements.
Specifications: Flanged elbow dimensions are defined by nominal diameter and bend radius. Bend radii are categorized as long radius (Long Radius, typically denoted as 1.5D) and short radius (Short Radius, typically denoted as 1.0D). Long-radius elbows provide smoother fluid flow paths, minimizing pressure loss, while short-radius elbows offer greater space efficiency.
Flanged Elbow Pipe Fittings
90° Flanged Elbow
The most common type, used to make a right-angle change in piping direction.
Applications: Equipment inlets/outlets, vertical pipe transitions.
45° Flanged Elbow
Used to alter pipe direction by 45 degrees.
Applications: Gentle directional changes, often used for branching or bypassing obstacles.
180° Flanged Elbow
Also known as a “U-bend” or “U-turn elbow,” it reverses the pipeline direction completely.
Applications: Commonly used for heat exchanger or tank inlets/outlets, or pipelines requiring a complete reversal.
How to Select the Correct Flange for a Flanged Elbow?
The key to selection lies in matching the system. You need to check the flange specifications of the equipment or pipeline connected to the elbow to ensure the following four points are completely consistent:
| Key Parameter | Explanation | Examples |
| 1. Standard System & Pressure Class | This is the most critical; American and European standards cannot be mixed. | ASME B16.5 Class 150 or EN 1092-1 PN16 |
| 2. Nominal Diameter (DN/NPS) | The connection size must be identical. | DN100 or NPS 4 |
| 3. Sealing Face Type | Determines the type of gasket used for sealing; must match to ensure a seal. | RF (Raised Face): Most common, uses non-metallic gaskets. |
| FF (Flat Face): Often used for low pressure, uses soft full-face gaskets. | ||
| RTJ (Ring Type Joint): For high pressure, uses metal ring gaskets. | ||
| 4. Material | The flange material must be compatible with the pipeline material and the medium. | A105 (Carbon Steel), SS304 (Stainless Steel), F11 (Alloy Steel) |
Applications of Flanged Elbows:
Oil and Gas Industry
Chemical Industry
Power Industry
Water Supply and Drainage Systems
Shipbuilding and Offshore Engineering
Food and Pharmaceutical Industries
Metallurgical Industry
Stainless Steel Flanged Elbow Manufacturer
As a leading manufacturer specializing in the R&D and production of flanged elbows, ZIZI leverages our deep understanding of pipeline system requirements to deliver a comprehensive range of high-quality products, including both single-flanged and double-flanged elbows. We provide reliable pipeline directional solutions for diverse industries such as petroleum, chemical, food and pharmaceutical, and municipal engineering. In manufacturing, we strictly adhere to international standards such as ASME B16.9 and ASME B16.5, implementing rigorous quality control throughout the entire process from raw material selection to finished product shipment: High-purity carbon steel, stainless steel (304/316/316L), and alloy materials are selected, with spectral analysis ensuring composition compliance; Elbow bodies are manufactured through integral forging or precision welding techniques, with flange sealing surfaces precision-machined. The entire product range undergoes hydraulic pressure testing and non-destructive inspection, guaranteeing exceptional structural stability and sealing performance under complex operating conditions including high temperatures, high pressures, and severe corrosion.