One of the most common applications of angle bending is to form complete rings which are called rolled angle rings, angle flanges, or companion angle rings. Such rings are made of angles as small as ½ x ½ x 1/8 and as large as 8 x 8 x 1. These rings are used as flanges to connect pipe, as stiffeners on cylinders, and as housing frames among other applications.
Over the decades, two types of angle rings were developed as stock items: standard angle rings and blowpipe rings. The two types of rings differ in their inside diameter, the angle size used, the bolt circles, the number of holes and hole sizes, and the weight of a ring.
For example, a 16in standard angle ring has an inside diameter of 16-1/4in, is made of 1-3/4 x 1-3/4 x 3/16 angle with a 18-1/8 bolt circle for 16 ea. 13/32 holes, and weighs 9.50lbs. A 16in blowpipe angle ring has an inside diameter of 16-1/8in, is made of 1-1/2 x 1-1/2 x 3/16 angle with an 18in bolt circle for 8 ea. 7/16 holes, and weighs 8lbs.
Standard angle rings tend to be a little heavier with a larger angle and more bolt holes. Standard angle rings are used in heavier applications, for example, in conveying grain. Blowpipe rings are used in lighter applications, for example, in conveying air, dust or other light particulate. Both types of rings work well in pneumatic conveying systems. They are welded to the outside of the pipe and therefore cause no interference to the flow inside the pipe.
The differences can be seen on charts that are provided by angle ring producers: one for standard rings and one for blow pipe rings.
Angle rings are available in most cases within a day of order placement. Since they do not involve custom fabrication, they can be purchased very economically. The inside diameters of the angle rings can accommodate welded, lock-seam and spiral pipe.
