Wing Unions

Wing Unions

Wing unions have been used in the oilfield services for almost a century. Wing unions have built a worldwide reputation with generation to generation of field operators.

The applied technologies of  wing unions have proven their high level of efficiency in extremely severe flow conditions such as very high pressure & flowrates, high & low temperatures, multiphase flow, erosive and corrosive agents, vibration in pumping piping systems, etc.

Wing Unions

Wing unions are also often referred to as hammer unions or hammer lug unions dependent upon the customer or manufacturer. Whatever name is used, they are the most common quick connection method for joining piping components together in a temporary system.

FCE is one of the most reputed manufacturers of wing unions approved by the major worldwide service companies. FCE products for oilfield services focus on sour gas service and most severe applications. In addition, FCE has developed wing unions for various industrial market applications including gas bottling plants, pipeline maintenance services & loading systems in LACT units. FCE is also a European leader in railcar couplings using specially modified wing unions.

Wing unions – Hammer unions are one of the most common “quick connection” methods used in the oilfield for joining together components in a temporary pipe work system. They also have expanding applications in fixed installations and also for industrial purposes.

Male & Female Subs

They are the pressure containing parts of the assembly that provide metal-to-metal primary seal.

 Subs are manufactured per different assembly modes:

  • Butt weld assembly
  • NPT threaded assembly
  • NPST threaded assembly
  • Sub profiles are also machined / forged as an integral part of a piping element.

This is a forged part of the assembly that allows connection of the two subs through a specific ACME or ISO thread.

Seal Element
Seal element is an elastomer component which acts as a secondary seal to protect metal-to-metal seal against corrosion. Depending on the union figure it can be a lip type ”Seal Ring” or an ”O-Ring”. Different materials are available to suit fluid service (Buna for standard service or FKM for H2S service).

NPST (Non Pressure Seal Thread)

  • The NPST assembly is a special design for higher pressure service which can replace welded or conventionally threaded union construction.
  • In this instance it can be seen from the illustration that the threads are not exposed to well effluent which is the case with conventional threaded (ie LP) components.
  • This type of construction, on straight flowline and pup joints, is generally more economically priced when compared to integral equipment

Avoid the DANGER for interconnecting 2 “Fig 602 and Fig 1002 with 2” Fig 1502.

Positively identify figure numbers and pressure ratings before connecting together 2 union halves.

  • Never strike, tighten, loosen or attempt repairs on pressurized components or connections.
  • Always apply essential care, handling and inspection to threaded components before, during and after make-up.
  • Never use severely worn, eroded or corroded components.
  • Never strike wing unions nuts having severely flattened and extruded ears.
  • Always use a bronze hammer in order to avoid sparkling while striking onto a wing union nut.


Plugs & Test Plugs

Male and female hammer union plugs are available in all figures and all sizes. When ported, plugs can be used for different purposes (pressure testing, end of line drainage or venting). Port is generally 1/2 “NPT but can be threaded to client requirement.

Grooved Nuts

Grooved nuts are generally used in industrial applications where assembly operation is more popularly done by the use of wrench rather than hammer.

Grooved nuts provide many advantages such as:

  • Fast tightening
  • Zero vibration, shock and deforming while tightening
  • Limited overall dimension for installation and storage

FCE offers grooved nuts for figure 602 in 2 “and 3” as well as suitable “Key Fore” wrenches.

Drilled Holes Nuts

FCE also offers drilled holes nuts for Figures 206 and 602 in 2 “, 3” and 4 “diameters for industrial applications.
With suitable” Weco Rail “wrenches.

Wear Check

Need help to inspect your thread wear? This wear-check trolley will help you.

Identification Kit

This kit allows you to easily identify your material.
You can combine as many figure and diameter as desired.

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