There are many categories of flanges. This video discusses long weld neck flanges, commonly referred to as nozzles. Long weld neck flanges are often shortened to LWN. LWNs are similar to weld neck flanges.
The main difference between an LWN and a weld neck flange is an LWN has an extended neck that acts as an extension.
LWNs are used most often on columns, barrels, and vessels. For barrels, there are two types of flanges to choose from heavy-duty long weld neck flanges and heavy-heated long weld neck flanges. These specialized long weld neck flanges are most often used in the gas, oil, and petrochemical fields. Unlike many other flanges, long weld neck flanges aren’t designed to be welded directly to pipes.
Long weld neck flanges are square and designed to be utilized with pipes. For this reason, long weld neck flanges aren’t created with scheduled balls. There’s also no universal length for long weld neck flanges. Instead, this equipment is usually made to order per project or customer.