Basic knowledge of elbows

Sources: this site    Click:    Date: 2019-12-25 3:9:59

Steel pipe elbow is an important parts in plumbing pipeline systems and used to change the fluid directions. It ranges in different types as per body material there are stainless steel elbow, carbon steel elbow, and alloy steel; As per fluid directions there are 45 degree , 90 degree elbow and 180 degree; As per elbow length and radius there are short radius elbow (SR elbow) and long radius elbow (LR elbow); As per connections types there are butt weld elbow, socket weld elbow and threaded steel piping elbow.

90 Degree Steel Pipe Elbow

90 degree steel pipe elbow is to change fluid direction by 90 degree, also called the vertical elbow, it is the most used type in all the pipeline systems, since it is easy to compatible with the steel construction and structural.

• 90 degree elbow of long radius
This kind of 90 degree steel pipe elbow is installed between different lengths of pipe or tubing.
It helps to change the direction at an angle of 90 degrees. It’s often used for connection of hoses to water pumps, deck drains, and valves.
• 90 degree elbow of short radius
The main use is just like the previously stated pipe, but the diameter is short. So this kind of piping elbow is often used when shortage of space.

45 degree steel pipe elbow

45 degree elbow is to change pipe direction by 45 degree, it is second common used type in industrial pipelines.

• 45 degree LR steel elbow
This kind of elbow is installed between two pipes so that the direction could be changed at an angle of 45 degrees. Since it creates lower frictional resistance, pressure also be lower.

• 45 degree SR elbow
This kind of elbow is usually attached to copper, plastic, steel, cast iron, and lead. It could also be attached to clamps of stainless steel and rubber. As a result, it’s widely used in chemical, food, facilities of water supply, electronic industrial and chemical pipelines, gardening and agriculture production, piping for solar power facilities, and pipelines for air conditioning.

180 degree steel elbow

This kind of elbow helps to change the direction at an angle of 180 degrees. Since it usually results in low pressure, its applications is limited to minimum deposition and low turbulence systems.

Butt weld elbow

The easiest way to connect the elbow and pipe is to do welding directly to the elbow ends with pipe ends, where we called butt to butt weld (BW Elbow, as showed in above picture). Butt weld elbow mainly used in a higher pressure and temperature than the other connection types of elbow. (Than socket weld elbow or the threaded piping elbow)

Socket weld elbow

Socket weld elbow also connected with ends welding, different with BW elbow is: Socket weld elbow ends has a ladder shaped area, which we can insert the pipe ends to this area (SW elbow ladder diameter fit with pipe outer diameter), after inserting do the welding work to joint them together.

So SW elbow ends actual out diameter is bigger than the elbow diameter. (Same with threaded pipe elbow). Such structural makes welding process more easy for the small diameter elbow and pipes.

Threaded Elbow 

Similar shape with SW elbow, different is ladder area inner surface has been machined to threads, it makes more easy to install and un-install. Which is good for the pipeline repair and maintenance.

Reducer Elbow

Also known as decreasing elbow, is a kind of pipe which applied when both the elbow and closures are different in size. It’s often used so that different sizes of the pipes could be easily distinguished in order to make noteworthy turns.