Connections through pipes are a crucial channel for transporting steam and fluids along with gas from refineries to factories or across continents as well. Flanges are one of the efficient components in a method to connect pipes. Along with forging connections in a piping system,
flanges regularly permit the worker with inspection points which are easy to modify and clean these systems. Different alloy grades are useful to produce various flanges that are a part of piping systems in the gas and oil industry.
Therefore, these flanges are required to not only be durable, but they must also be easy to install and maintain.
Below are a few of the commonly sighted flange types used in the gas and oil industry:
Weld Neck Flange
Useful in high-pressure environments, it is easy to recognize the weld neck flanges because of the beveled hub. Moreover, weld neck flanges are particularly well suited to be used in repeat bending conditions. These flanges are attached to a piping system by means of welding the pipe to the flange neck.
Therefore, stainless steel grades have good weldable properties preferred for its manufacture. Weld neck types not only reduce the stress concentration from the base of the hub but also aid the transference of stress from the flange to the pipe.
Slip-on Flange
Slip-on flanges are designed to be used in lower-pressure, low-temperature processes. These are favored by the engineers in the gas and oil industry due to their economical value in comparison to the weld neck flanges.
This kind of flange is slipped over the pipe, following which they are welded both on the outside and inside to increase its strength and prevent leakage.
Lap joint
A lap joint flange is a two-part attachment preferred to be used in processes where space constraints and frequent dismantling are primary requirements. In this type of attachment, the lap joint stub end is welded to the pipe, and the loose backing flange is used in conjunction to slip over the pipe or stub end.
As the backing flange is not in contact with the product in the piping systems, moderate corrosion resistance and less expensive material with high hardness like carbon steel is good to use. Also, the stub ends need to be highly corrosion-resistant material with good mechanical properties.
Threaded Flange
It is useful in circumstances where there’s a need for quick fixes. Threaded flanges or as referred to as screwed flanges are produced with threaded bores that aid in a fast and simple attachment.
A threaded flange is usually attached to the pipe without a need to carry out a welding operation due to the pre-existing threads. Typically, threaded flanges are seen in the processes where the pipes in the systems are used to transport water or air. Threaded flanges are best used in low-pressure environments and temperatures.
Blind Flange
The production of blind flange is done without a bore at the center and the main purpose of using it is to blank off the end of valves or piping systems or even pressure vessel openings.
Blind flanges could also be used in conjunction with any other flange to isolate a piping system in the gas and oil industry. Furthermore, they make an excellent manhole, especially if they perform the tasks of terminating the flow in the vessel or a piping system.
Socket Weld Flange
It is recommended to be used for low-temperature and low-pressure settings, the socket weld has a static strength that is equal to a slip-on flange. A socket-weld connection is made with the pipe by using a filler weld performed on the outside of the flange.
Socket weld flanges are designed to be used in processes where small bore piping is needed. However, due to some corrosion issues, it is best to avoid these in a few processes.
If you still have any doubts about how to select flanges for the oil and gas industry and what to look for, do let us know in the comment section or call us today!
