Guidelines for selection of various types of flanges?
A pipe flange is a protruding rib, rim, edge, or collar used to create a connection between two pipes or between a pipe and any other type of fitting or piece of equipment. Pipe flanges are used for temporary or mobile installations, dismantling piping systems, and connections in environments that are not conducive to solvent bonding. They are well known, reliable, cost-effective, and readily available from a wide range of providers.
What are the different types of flanges?
Blind Flanges are referred to as circular plates without a clamping center, used to close the ends of pipes, valves, or equipment. They facilitate easy access to the line after sealing it. Blind flanges are used to install standard pipes of various sizes at higher pressure ratings than other types of flanges.
The Slip-on Flanges are designed to be slipped over the end of the pipe and then welded into place. They offer simple, low-cost installation and are ideal for low voltage applications.
Lap Flanges are used on pipelines equipped with lap pipes or short ends of lap joints. Even after welding is complete, they can be rotated around the pipe for easy alignment and mounting of bolt holes. The pressure rating of lap flanges is lower but higher than that of slip-on flanges.
Socket Weld Flanges are ideal for small high-pressure pipelines. They are manufactured similar to slip-on flanges, but the internal pocket design allows for smooth holes and better fluid flow.
Threaded Flanges are a special type of pipe flange that can be connected to the pipeline without welding. They are threaded into the hole to match the external pipe threads and are tapered to create a seal between the flange and the pipe.
Buttweld Flanges have a long tapered hub for high-pressure applications. The tapered hub transfers stress from the flange to the pipe and provide strength reinforcement to counteract buckling.
What are the criteria for selecting various types of flanges?
1. Flange Size
In order to choose the best quality flanges, it’s important to have a proper fit. Other than functional flange design, flange size is the most likely factor affecting flange selection when designing, maintaining, or upgrading a piping system. Before choosing, you must consider how the flange interacts with the pipe and joint in use to ensure correct sizing. Some of the common considerations may include:
a. Outside diameter: The distance between two opposite edges of the flange face
b. Thickness: A measure of the thickness of the outer connecting edge
c. Bolt Circle Diameter: The distance between opposing bolt holes when measured center to center
d. Pipe Size: The name of the pipe size corresponding to the flange
e. Nominal Bore Size: The measured value of the inside diameter of the flange connector
2. Flange Subject
There are a wide variety of flanges having different subjects available in the market. The forged carbon steel pipe flanges are the most common type found in the market. Besides that, one can also find flanges made of stainless steel, aluminum, cast iron, and bronze. You can also find flanges made of specialty metals like monel, Inconel, and chrome molybdenum. The type of material used depends on the industrial application and the piping system. This is to ensure that they are strong enough in the long run.
3. Flange Marking
For the easy purpose of distinction, the flanges meet global standards set by the American Society of Mechanical Engineers (ASME): ASME B16.5 and B16.47. If you are trying to replace or verify an existing part, all flanges should include markings, usually on their outer perimeter, to aid in the process. Flanges carrying verification marks are a testimonial of high quality and durable material, which will serve you well in the longer run.
It is hence a fact that flanges have become one of the crucial additions of the industry, which has a wide variety of uses and benefits. Due to extensive features, these flanges have become one of the popular products of today’s age.