Flange  Facilities  Process 

Flange

Welding Neck

Weld neck pipe flanges attach to the pipe by welding the pipe to the neck of the pipe flange. This allows for the transfer of stress from the weld neck pipe flanges to the pipe itself. This also reduces high stress concentration at the base of the hub of the weld neck pipe flanges. Weld neck pipe flanges are often used for high pressure applications.

Threaded (Screwed)

Screwed or Threaded flanges are attached to the pipe like any other screwed fittings, and may be back-welded to seal the joint between pipe and flange. Although still available in most sizes and pressure ratings, screwed fittings today are used almost exclusively in smaller pipe sizes and at low pressures.

Slip-On

Slip on pipe flanges actually slip over the pipe. These pipe flanges are typically machined with an inside diameter slightly larger than the outside diameter of the pipe. Slip on pipe flanges are secured to the pipe with a fillet weld at the top and the bottom of the slip on pipe flanges.

Compact

A compact flange, similar to a swivel ring flange, is a two-piece constructed flange used extensively for offshore pipelines, offshore industry applications and onshore and sub-sea applications. Its double sealing action prevents hydrocarbon releases to address health and safety issues and concerns.

Spectacle Blind

A spectacle blind is a safety device used to isolate a section of line or piece of equipment when the line or equipment needs to be inspected or removed from service. It is different than a valve in that the blind is a permanent or long term isolation device.

Orifice

An Orifice Flange is intended for use instead of standard pipe Flanges when an orifice plate or flow nozzle must be installed. Pairs of pressure tapings are machined into the Orifice Flange, making separate orifice carriers or tapings in the pipe wall unnecessary.

Socket Welding

Socket Welding flanges have counter bore is slightly larger than the Outer Diameter of the matching pipe, allowing the pipe to be inserted. A restriction is built into the bottom of the bore, which acts as a shoulder for the pipe to rest on, and has the same ID of matching pipe.

Lap Joint

A Lap Joint Flange is usually used in conjunction with Lap Joint Stubs. Lap Joint Flanges in carbon or low alloy steel piping systems are best used when frequent dismantling for inspection and cleaning is required. The use of Lap Joint Flanges at points where severe bending stress occurs should be avoided.

Blind

A Blind Flange has no bore, and is used to close ends of piping systems. A blind flange also permits easy access to a line ones it has been sealed. The blind flange is sometimes machined to accept a pipe of the nominal Size to which reduction is being made. The reduction can be either threaded or welded.