Getting connected

Compact connection and sealing technology now being introduced in Australia spells some significant advantages to process plant operators, from oil, gas and petrochemical to minerals processing and more.

At the top of any process plant operator's priorities will be keeping the plant operating and performing efficiently and perhaps nowhere more so than in the oil, gas and petrochemical sector. Since leakage can be costly in terms of energy consumption and lost product or, worse, potential unscheduled down time, as well as raising issues over emissions and consequent safety or environmental concerns, avoiding leakage inevitably becomes a fundamental requirement in effective plant management.

Any point where piping, pressure vessels, heat exchangers and other interfacing plant components are connected is a potential weak point where leakage can occur. And yet a technology that is widely accepted as prone to leakage, the traditional ANSI flange, is still the most commonly used method for such connections.

Now, with technology being newly introduced to Australia, there are alternatives that are drawing increasing attention among oil, gas and petrochemical plant operators for their compact size, high performance and numerous additional benefits.

Whereas ANSI flanges, which have been around for many years and have not been significantly developed or improved in that time, tend to be large, heavy and cumbersome (particularly where high pressures are involved), are time consuming to install with extensive bolting and require regular maintenance; the latest compact sealing solutions overcome all these issues.

Unlike a traditional ANSI flange which is bolted to hold the two flange faces together (so the loading is on the bolts and joint integrity is largely dependent on bolt torque), connection technology such as Vector's SPO compact flange and Techlok clamp connector incorporates an internal seal ring which, when set up correctly, will provide a leak-free seal. Where leaks are unacceptable but a welded connection (the ultimate leak-free solution) is not practicable due to its permanency, or because welding is not desirable, these compact flanges and connectors provide the best of both worlds: the integrity of a welded joint with the versatility of a mechanical one.

Like an ANSI flange, the SPO compact flange uses radial compression but combines this with a wedging action, placing 90% of the loading on the heel area to ensure a rigid, full contact between seal faces which remains static regardless of load fluctuations, guaranteeing the no-leak capabilities. Neither dynamic nor static loading will degrade seal performance or adversely affect the corresponding pipe or interfacing component. Such is the assurance of the no-leak capabilities that the SPO compact flange (which is claimed never to have leaked in service) is typically used where leaks are unacceptable, making it particularly valuable for process plants where hazardous substances are being produced or used.

The strength of the Techlok seal, on the other hand, lies in its pressure-energised metal-to-metal seal which, unlike a conventional flange, does not rely on bolting to maintain seal integrity. Once the clamp has been made up and bolted in position, the seal becomes effectively self-energised by the pressure within the pipe (whereas with a traditional flange the pressure is effectively trying to force the two faces apart).

Moreover, being compact, both the Techlok clamp connector and SPO compact flange offer significant space and weight savings over ANSI flanges for the equivalent pressure rating ( typically 70 to 80% smaller and lighter), making them particularly suitable for applications in confined spaces or congested plants where clearance can be a problem and are able to withstand pressures in excess of 40,000 psi in temperatures from -254 to 950°C.

A further advantage lies in the connectors' reduced bolting requirements (Techlok uses only four bolts), which make them quicker and easier to install. Several Techlok connectors, for instance, can usually be made up in the same time as one ANSI flange, which would have at least eight bolts and often many more in larger sizes. The bolting arrangement also requires less tightening than a typical flange as leakage is prevented not by bolt torque but by the inner seal ring.

Maintenance requirements, and therefore costs, are also minimised by the design of the connector and compact flange, which protects the seal ring from corrosion. Given the widespread challenge faced by oil, gas and petrochemical maintenance managers to optimise plant performance on minimised budgets, selecting products such as the SPO compact flange and Techlok clamp connector over traditional ANSI flanges can represent a valuable contribution, helping to reduce maintenance engineers' time spent on piping and pressure vessel connections with the assurance of reliable joint integrity. Once pressure-tight after assembly, an SPO compact flange, for example, being a static connection, will remain pressure-tight.

In sectors such as oil and gas refining and petrochemical industries where high pressures and temperatures and hazardous substances are commonplace, the benefits of this compact connection and sealing technology, able to withstand demanding operating conditions with assured joint integrity are extremely valuable, contributing to improved plant efficiency with economic, environmental and safety benefits. Coupled with the space and weight savings (overcoming common issues presented by congested piping systems or the need to install at high level), plus the reduced assembly/disassembly time and minimal maintenance requirements, the advantages and value of this technology are compelling. Not surprisingly, SPO compact flanges and Techlok clamp connectors are attracting growing attention among plant operators across Australia and New Zealand.