Types of Elbow Fittings in Piping

1. **90-Degree Elbows**: These elbows are the most common type and provide a 90-degree change in direction. They are available in both right-angle and left-angle configurations. 90-degree elbows can be used for both headers and branch lines and are available in a variety of materials and schedules.

2. **45-Degree Elbows**: As the name suggests, these elbows offer a milder direction change, providing a 45-degree angle. They are often used when a less restrictive flow path is desired or when space is limited.

3. **Straight Through Bends**: Also known as return bends or tee bends, these elbows have a design that allows the pipe to change direction while maintaining a straight run. They are less restrictive than standard elbows and are commonly used in applications where flow efficiency is critical.

4. **Reducing Elbows**: These elbows are designed to connect two pipes of different sizes, reducing the diameter of the flow. They are useful when transitioning from a larger pipe to a smaller one.

5. **Socket Weld Elbows**: These elbows are joined to the pipeline using socket welding, which is a process where the socket on the elbow is heated to allow the pipe to be inserted and then cooled to create a permanent joint.

6. **Butt Weld Elbows**: Butt weld elbows are joined to the pipeline using butt welding, a process that involves melting the ends of the pipe and elbow together to create a strong, permanent bond. They are available in various radii and are often used in high-pressure and high-temperature applications.

7. **Socketless Elbows (Smart Bends)**: These elbows are designed without a socket and are typically push-fit or hammer-welded. They are used in applications where a traditional socket weld or butt weld is not feasible or desired.

8. **LJ (Lined J) Elbows**: These elbows have a lined or jacketed construction, which is often used in applications where there is a risk of corrosion or when different fluids need to be isolated.

9. **Corrugated Elbows**: These elbows have a corrugated or wave-like design, which can provide additional flexibility and reduce stress on the pipeline. They are often used in applications with significant temperature changes or vibrations.

10. **Extra- Heavy Elbows (XX-Highwall)**: These elbows have a thicker wall than standard elbows and are used in applications requiring increased strength or pressure containment.