Pneumatic conveying systems are extensively used in various industries worldwide for transporting various materials and substances. Within these systems, elbows or bends are an essential component. They are crucial in redirecting the process stream at different angles, vital for maintaining the appropriate material flow and preventing system clogging. However, two types of elbows are used in pneumatic conveying systems – short-radius elbows and long-radius Elbows. In this blog post, we’ll explain the key differences and their benefits so you can choose the most suitable option for your next project.
What Is A Short-Radius Elbow?
A short radius elbow is a type of pipe fitting used in plumbing and industrial piping systems. It is designed to change the flow direction in a pipeline at a sharp angle, typically 90 degrees. The important feature of this elbow is its shorter length compared to other types, allowing for tighter turns and more compact installations. This makes it an ideal choice for tight spaces or when obstacles are present. These elbows are typically made from stainless steel, carbon steel, or brass materials and can handle high pressure and temperatures. Their precise design ensures minimal fluid flow disruption through the pipeline.
Definition
Short radius (SR) elbows are typically less than one pipe diameter, and long radius (LR) elbows, alternatively, are about two and a half pipe diameters. LR elbows have a gentler turn than SR elbows, making them less abrupt. The sudden direction change caused by SR bends can increase fluid velocity, increasing wear and tear on the system and potentially affecting the quality of the conveyed materials. On the other hand, the gradual change in the direction of LR elbows lowers the rate of fluid velocity and wear and tear on the system.
Pressure Drops
Another significant difference between short and long-radius elbows in pneumatic conveying is the pressure drop. As mentioned earlier, SR joints have a sharp change in direction, which leads to an increase in fluid velocity and consequent loss in static pressure. It results in a higher pressure drop between the bend’s inlet and exit. The pressure loss caused by SR elbows can lead to considerable energy loss in pneumatic conveying systems. In comparison, the gradual bend in LR elbows causes comparatively less fluid acceleration and less pressure drop.
System Maintenance
Long-radius elbows are better for maintenance as they provide more space to access the elbow compared to short-radius elbows. In SR elbows, limited space is available for cleaning, inspection, and maintenance work.
Material Compatibility
Various materials like abrasive or high-density materials need optimum conveying distance to avoid system clogging, which can damage the material being transported. LR elbows are preferred in such cases because they allow proper material flow without material build-up.
Cost
The cost of the elbow depends on several factors, such as material, size, and make. Typically, the price of a long-radius elbow is higher compared to its SR counterpart. However, the additional cost of LR elbows is worth it, resulting in reduced maintenance costs and lower pressure drops.
Conclusion
In conclusion, selecting the appropriate pipe elbows concerning radius is vital in any pneumatic conveying system. However, it is essential to consider your material’s specific requirements and convey the system before selecting either short or long-radius elbows. Based on the above factors, long-radius elbows are generally better than short-radius elbows, considering their reduced pressure drops, lesser space requirements, and better material compatibility. However, it is always best to seek expert advice before deciding which one to use.
