What Is an Elbow Pipe Fitting?
An Elbow Pipe Fitting is a type of pipe fitting used to bend a pipeline flow path 90 or 45 degrees. They are called 90-degree elbows and 45-degree elbows, respectively. Bends are similar to elbows in that they are manufactured in a different way.
The connection method of elbow pipe fittings vary depending on the surrounding environment and the bore size. There are several types, such as flange connections when open piping is expected, and welded connections when leakage prevention is desired.
Uses of Elbow Pipe Fittings
Elbow Pipe Fittings are used to change the direction of piping. For example, in everyday life, elbows are found in water and sewage piping, and in industrial applications, elbows are often used in factory water piping.
Elbow pipe fittings cause pressure loss, so they must be designed according to Fanning’s formula to minimize the number of elbows.
There are two types of elbows: long elbows and short elbows. Short elbows have a small radius of curvature and thus save space. Long elbows have a large radius of curvature but are available at a lower cost. Generally, long elbows are used.
Principle of Elbow Pipe Fittings
The working principle of an elbow pipe fitting is to bend the flow of fluid by decelerating the fluid at the point of bending. Elbows play an essential role in properly controlling the flow of fluid inside a piping system and ensuring that the piping system functions properly.
Elbows are made of metals such as chrome or nickel, depending on the material. Depending on the material, elbows are characterized by high corrosion and wear resistance and can withstand repeated use.
Elbows can be connected by either a screwed-in or welded connection method. The screw-in type is connected by screwing it into the piping, which is easy to remove, but is not as strong and may cause leakage. On the other hand, the welding type connects pipes by welding them together, which is stronger and less likely to cause leakage, but has the disadvantage of being difficult to remove.
Other Information on Elbow Pipe Fittings
1. Elbow Pipe Fitting Materials
There are various types of elbow fittings depending on the material. The most commonly used is made of malleable cast iron. They are called black fittings because of the color of the material. A hot-dip galvanized joint made of the same material is called a white joint.
Stainless steel fittings are used to prevent corrosion.
2. Types of Elbows and Piping
There are two types of connections between elbows and piping: threaded and welded.
1. Screwed-in type
This is a method in which the elbow and piping are each threaded. Since the elbow and piping are simply screwed together, there is no need for bolts and nuts. Also, on-site welding is not required, so it can be installed in fire-prohibited areas. However, the larger the bore size, the more difficult it is to seal and install. Therefore, flanged or welded connections should be used for larger diameters.
Threaded elbows are generally installed with sealing tape wrapped around them. The direction of the sealing tape should be in the direction of tightening.
2. Welding type
Elbows are connected to pipes by welding. Accurate welding prevents leakage. However, the degree of completion depends on the skill of the welder. There is a risk of corrosion due to poor welding.
Difference Between Elbows and Bends
Elbows and bends are manufactured in different ways. Bends themselves are manufactured by secondary processing of formed pipes. In other words, the pipe is manufactured by bending it.
Elbows, on the other hand, use a process called Hamburg bending (hot expanding mandrel process). By bending a steel pipe while expanding it, this manufacturing method prevents differences in wall thickness between the inside and outside of the elbow.