45° LR Butt Weld Elbow

The function of 45° Butt Weld Elbow in the piping system is to change the fluid direction. About the degree, there are 3 common types, 45°, 90° and 180° which have long radius of LR, in addition, 90° and 180° Elbow also has short radius of SR.

Butt Weld Elbow Types are: LR and SR, which are the distance of direction. The distance from one end of the center to the other is the distance from the center to the end, which is the bend radius of the elbow.

For the LR Elbow, the center to the end of the distance is 1.5x nominal diameter NPS, for the SR Elbow, the distance between the center to elbow end is nominal diameter NPS.

For example,NPS 2 Elbow, the calculation of the distance from the center to the end as follows:

1. 90°- 2″- LR : = 1.1/2 x (25,4 x 2) A = 76,2 mm
2. 180°- 2″- LR : = 1.1/2 x (25,4 x 2) x 2 A = 152,4 mm
3. 3. 90°- 2″- SR : = 25,4 x 2 A = 50,8 mm
4. 4. 180°- 2″- SR : = (25,4 x 2) x 2 A = 101,6 mm

 

45° Elbow

The function of the 45° Butt Weld Elbow is the same as 90° Elbow, but the distance measurement method is different. The bending radius is also same, but the distance from the center to the end is different. 45° Elbow from the Center to the end is the distance from the intersection of the end face to the center perpendicular. See the distance B in the below figure. 45° SR Elbow does not exist.

ASME Elbow

The most commonly used is 90° long radius elbow and 45° butt weld elbow. When room is small, use 90° short radius elbow. The function of the 180° elbow is to change the flow of the fluid to 180°. 180° Elbow has long radius and short radius, its center to center distance is twice time of 90° elbow Center to the end. This type of pipe fittings is mainly used in boiler and heat exchange system. In addition to the above elbow, there is reducing elbow that the size of ends are different. This type of elbow is usually with high cost and price, long delivery, and replaced by a standard elbow and a reducer.

Other degree elbows can be bended by standard elbow. Longer bending radius, such as R=3d. The size and tolerances are according to ASME B16.9. which require minimum wall thickness shall not be less than 87.5% of the nominal.