The ultimate connection

Grayloc Products designs and manufactures the original high performance Grayloc clamp connector, and has the largest installed base worldwide.

The Grayloc connector has been a unique device for connecting piping systems for over 50 years, these connectors are used extensively in production manifold, flow line, and valve installations and the Grayloc brand has become the recognised standard for clamp connectors and is synonymous with quality and reliability.

Lighter and stronger than a flange, it seals through the elastic action of a reusable metal seal ring. The Grayloc connector provides immediate savings in weight, space, fabrication and assembly time, as well as continuing advantages in maintenance costs and improved performance. Grayloc connectors have applications in a wide range of industries, including oil and gas production, petroleum refining and industrial gas manufacturing.

The Grayloc product line is manufactured in three locations: Houston, Texas; Aberdeen, Scotland and Dubai in the Middle East. This gives the company the ability to offer worldwide customer support, and the new site in Dubai also offers additional capacity and a logistical advantage. The highly skilled and dedicated workforce is supported by field sales and service personnel that are available to provide training, inspection, installation and on-site machining/supervisory services 24 hours a day, seven days a week.

The engineering and technical support available includes numerous in-house computer programmes that have been developed to provide sizing information, stress calculations, finite element analysis and product application assistance to customers on a timely basis. There are also engineers available who are experienced in testing, materials application and stress analysis to assist customers with special applications.

Working in partnership with its clients is also a big part of the ethos at Grayloc, and it routinely co-ordinates and provides OEM companies the machining details for interfacing their equipment with the specified Grayloc hub profiles. Often, components are co-ordinated and separated for shipment to OEM equipment manufacturers, piping contractors and the project site.

The product
A Grayloc connector has three components: a metal seal ring, two hubs and a clamp assembly. The seal ring is a ‘T’ in cross section. The leg of the ‘T’ forms a rib that is held by the hub faces as the connection is made. The two arms form lip seals that create an area of sealing surface with the inner surface of the hub. The clamp fits over the two hubs and forces them against the seal ring rib.

As the hubs are drawn together by the clamp assembly, the seal ring lips deflect against the inner sealing surfaces of the hubs. This deflection elastically loads the lips of the seal ring against the inner sealing surface of the hub, forming a self-energised seal. Internal pressure reinforces this seal, so that the sealing action of the Grayloc connector is both self-energised and pressure-energised.

When manufactured from the same material as the pipe, the Grayloc connector surpasses the strength of the pipe and that of most other components. The rib of the seal ring prevents the seal lip from being crushed by over-tightening. While it acts as a positive stop during makeup, the rib also transfers compressive and bending loads from one hub element to another. The rib has bearing area ample to carry the most severe loading that the piping system can withstand.

There are a multitude of benefits offered by the Grayloc connector in comparison to bolted flanges for example. In the fabrication of piping systems, less time is required to weld Grayloc hubs to the pipe. In the installation of piping systems, less time is required for assembly of Grayloc connectors since there are no bolt hole alignment problems and only four bolts to tighten rather than eight to 24 as on a conventional flange, and the torque required to make up a Grayloc connection is less than that of a ring joint flange – as much as 75 per cent less. Maintenance is considerably simplified by the fact that removing four bolts will free a connection. Make and break times are much shorter, usually in the range of three to eight Grayloc connectors in the same time as one flanged connection. No periodic retightening of bolting is required once the connection is in service and seal rings can be reused when service conditions allow.

Compared to conventional ANSI or API ring joint flanges, the Grayloc connector is significantly lighter and smaller. The diameter of the clamp is less than that of a flange and the length of the weldneck is also shorter than that of a comparable flange, further reducing weight and space. The clamp may be rotated a full 360° around the hub to orient the bolts for most convenient tightening. As opposed to flanges, Grayloc connectors allow components, such as valves, to be installed with no regard to bolt hole alignment.

These four factors – smaller diameter, shorter length, freedom to rotate the clamp with no bolthole alignment constraint – provide an opportunity to design lightweight and compact systems. For example, a reduction of more than 15 inches in length and 11 tons in the production unit for an offshore platform in the Gulf of Mexico was achieved using Grayloc connectors.

The standard Grayloc assembly has two hubs arranged for butt-welding to pipe. However, a complete line of other piping components is available, including branch fittings, socket weld, threaded hubs, compact flanges and remotely operated connectors.

After reading the benefits of the device, the fact that the Grayloc connector has become the recognised standard for clamp connectors is not surprising. Added to the benefits of the connector is the expertise of Grayloc and the fact that the company is part of Oceaneering, a global oilfield provider of engineered services and products primarily to the offshore oil and gas industry. Grayloc became part of Oceaneering in 2005, and at the time of the agreement, John Huff, chairman and chief executive officer, stated: “We intend to jointly endeavour to grow clamp connector sales worldwide, develop synergies with our current pipeline connectors, and explore growth opportunities with the acquired technology.” The past four years have delivered on these aims – and the future promises further growth and development.


Products: Connectors