Fitting Used To Change Direction Of A Pipe -Material And Type Selection Options

Fitting Used To Change Direction Of A Pipe Core Function

In industrial piping systems, there are many scenarios where the direction of the fluid needs to be changed. Our steel pipes are straight and cannot be bent. At this time, fitting used to change direction of a pipe comes into play. Its core is to achieve fluid transmission by changing direction.

Fitting used to change direction of a pipe: classified by bending angle

• 45° elbow: It is a common pipe fitting for changing the direction of fluid. This bending angle is not common, and it will not cause much flow resistance to the fluid, and it can reduce local stress.
• 90° elbow: This is the most common type of elbows of all angles. This type of elbow accounts for 60% of all elbows used. It is used for right-angle turns and can quickly change the direction of the fluid.
• 180° elbow: Also known as a return elbow, it achieves the reversal of the flow direction of the pipeline and forms a straight loop. Elbows at this angle will withstand greater fluid impact, so they are usually designed to be very strong and can withstand greater pressure.
• Special angle elbow: This elbow is used for direction changes at non-classical angles. The angle can be customized according to your needs, meeting the requirements of diversified, complex, and special angle transformation pipeline layout.

Fitting used to change direction of a pipe: classified by the radius of curvature

Definition of curvature radius: The classification of elbows by curvature radius means that the arc bend is made according to the ratio between the radius of the bending part and the diameter of the pipe.

• Long radius elbow (LR)
  Bending radius R=1.5D
  This bending radius is longer, so the turning angle is gentler, so that the fluid resistance is less affected by the turning and the wear is lower.

• Short radius elbow (SR)
  Bending radius R=1D
  This bending radius is shorter, so the turning angle is more abrupt, and the fluid is subject to greater resistance, but this type of elbow will save more space than the long radius elbow and is suitable for use when space is limited.

Material selection for fitting used to change direction of a pipe

To avoid electrochemical corrosion or thermal expansion differences caused by material differences, the material of the elbow should be consistent with that of the connected pipe.

• Carbon steel elbow
  The elbow of this material has low cost and high strength, but it is not corrosion-resistant and easy to rust, so it needs anti-corrosion treatment.
  Standard: GB/T 12459, ASTM A234 WPB
• Stainless steel elbow: This type of elbow is resistant to high temperature and high pressure, and corrosion-resistant. 316 is suitable for use when the fluid medium contains chloride ions.
  Standard: GB/T 12459, ASTM A403 WP304
• Plastic elbow: This type of elbow is light in weight and corrosion-resistant, but not resistant to high temperature. Commonly used plastic materials include PVC, PP-R, etc.
  Standard: GB/T 20041, ISO 15874}
• Alloy steel elbow: This type of elbow contains other metal elements (chromium, molybdenum, etc.), is resistant to high temperature and high pressure, and can be improved through heat treatment.
  Standard: GB/T 12459, ASTM A234 WP11

FAQs:

1. What is the difference between elbows and pipe bends?
Elbows are standard pipe fittings prefabricated in factories, while pipe bends are customized pipe fittings that need to be processed on site.
2. How should these elbows be connected to the pipes?
They can be connected by welding, socket welding, flange connection, and threaded connection.