If all you know about elbows is that you aren’t supposed to eat with them on the table, you are about to learn a few things.
WHAT DO ELBOWS DO?
In addition to the flex point for your arm, elbows are industrial fittings that change the direction of piping. The connections allow you to reroute regularly threaded pipes to turn corners or fit in limited space without the expense of buying a pipe bender.
Standard elbows come in a few different angles – 45°, 90°, and, although they are less common, 22.5° angles – and can be made of the same materials as any other piping. We have a wide selection of elbows and other fittings in Stainless Steel 304 or 316.
TYPES OF ELBOWS
Although the names are mostly self-explanatory, there are a few variations in the elbows that are worth exploring.
The 90° elbow is also called a “90° ell” (pronounced like the letter “L”) or sometimes a “quarter bend” because the right angle at which flow is redirected is one quarter of 360°.
The 90° elbow is used in spaces that require a major turn. Although this may be a necessity, the flow rate and pressure within the pipe is affected. Just as with any piping system, the material under pressure hits the elbow and would like to continue in the same direction. When it meets the resistance of the elbow wall, it is forced to change direction (deflected) at a cost to the pressure.
The internal length of the elbow plays a part in that resistance. A quarter bend elbow made to fit in a tight space will create more pressure loss because the material being transported has to make the change more rapidly.
Elbows with a center-to-face dimension of 1X the pipe size are called “short radius” bends and force a quick turn.They have greater pressure loss than “long radius” bends which have a center-to-face length of 1.5X the pipe size. The distance traveled within the fitting is farther, creating a smoother transition for the material, which also means less turbulence in the system.
Long radius bends are used when flow rates are more important than space preservation in the plumbing system design. Both 45° and 22.5° ells tend to be long radius, which means they have less pressure loss than 90° ells.
Elbows come in a variety of connections, including threaded, weldable, socketed and flanged. When it comes to threaded elbows, male-x-male and female-x-female connections are most common. “Street elbows”, however, come in male-x-female configurations.
Elbows normally have the same size connection on both ends. When one is smaller than the other, that fitting is called a “reducing elbow”. These should be used with caution, as the change in pipe diameter will result in a change in pressure.
All of these factors should be considered when looking for the right elbow for your project. Otherwise you might end up with the “left” one.
Ahhh, word play is fun.