Weld Neck Flange is flanges that designed to be joined to a piping system by butt welding. This kind of flange include lots of specification. Weld Neck Flange is expensive because of its long neck and cost of people for contact WN flange with pipeline or fitting but is preferred for high-stress applications. The necks, or hubs, transmits stresses to the pipeline.

Slip on flange also named as SO flange. SO flanges slip over pipes and are designed to bit slightly bigger on the inside than the pipe. They connect to the pipe through a fillet weld at the flange top and bottom. It is used to insert the pipe into the inner hole of flange, as the flange inner diameter is little bigger than the pipe’s outer diameter, pipe and flange could be connected by lap welding at the top and bottom of the flange.

Blind flanges, just like standard pipe flanges, can be raised face (RF) or flat faced (FF). If the flange is RF we would recommend a standard ring gasket that is appropriate for the service and/or test. If it is FF we would TYPICALLY use a full face gasket, because the most common reason the flange is FF is that it is not designed to handle the bending forces that result when using a ring gasket or a RF flange against the FF flange. Again, we treat a blind flange just like any other pipe flange.

Socket weld flange simplified as SW flange, it has a recessed area (like a shoulder) in the flange bore, this shoulder serves as a guide to set the depth of the pipe that inserted to the flange. Socket welding flange initially designed for high pressure small diameters piping system.

Threaded pipe flanges are the special type of flanges which can be attached to the pipe without welding. Threaded flanges are threaded in the bore which matches an external thread on the pipe. Threaded pipe flanges is just like to slip-on pipe flanges that are used with pipes that have external threads. It is used where small diameter and high pressure is required. These flanges are available in all materials, specifications, sizes and grades.

Spectacle Blinds are generally applied to permanently separating pipe systems, or just to connect with each other. A Spectacle Blind is a steel plate cut into two discs of a certain thickness. The two discs are attached to each other by section of steel similar to the nose piece of a pair of glasses. One of the discs is a solid plate, and the other is a ring, whose inside diameter is equal to that of a flange.

Lap joint flanges are popular in both piping and duct system design. But as with all flanges and piping system components, understanding both how the component functions and how various design differences will impact performance are essential to safe, reliable operation and optimal cost-effectiveness.