An obvious first step towards cost saving when  producing compressed air might be to instal the most economical compressor for the job. But that is only a part of the story. Moving from traditional galvanised steel to Legris

Once installed, pressure drops through galvanised pipework can be extensive, so the compressor must work harder - and at greater cost - to supply the required quantity of air. Condensation building in this type of pipework leads to internal rusting which will quickly contaminate the air supply and, of course, lower the pressure through the system even further. If left unattended, the rust perforates the pipework leading to actual leaks.

Ease of installation

Recognising that, although time-honoured, galvanised steel is often far from the best method through which to transmit compressed air, a number of companies have begun to develop alternatives in recent years. With most of them, quite rightly, the attention has been on ease of installation to minimise downtime, and of a guaranteed supply of good, clean - though not necessarily economical - air.

These new systems have relied on different materials for pipework, principally to eliminate the age-old problem of rust. Nylon or plastic tubing, used in a variety of other applications, was certainly clean, but  glued connections required curing time - which translates into system downtime - of anything up to 24 hours.
The development of push-fit  connections overcame the need to glue lengths of plastic pipework,  but for most serious compressed air operations the problems of economic air supply through these types of material have been insurmountable.

Particularly in a warm environment,  plastic or nylon tends to sag, collecting moisture and reducing the flow of air, while ultra-violet light will ultimately cause it to become brittle, leading to cracks and leaks.

Aluminium tubing

Box-shaped aluminium tubing, again produced originally for an entirely different purpose, has proved effective against corrosion, but less so in terms of best air flow. Flow paths are not consistent and are hampered even further by the insertion of connectors that reduce the pipework’s internal bore.

When specialist pneumatic equipment manufacturer Legris looked at the requirements of compressed air pipework and connectors to match the growing sophistication of modern compressors, the need to design a  system specifically for the purpose became evident. Key criteria in developing the Transair range were corrosion resistant tubing that offered the lowest pressure drops,  and instant push-fit connectors that did not affect flow.

System assembly and modification had to be rapid, for the least possible downtime, and components interchangeable and reusable for best economy. Since its introduction 10 years ago, the Transair range has grown to six sizes, from 16.5mm to 101mm pipework sizes, with flow rates far greater than for galvanised systems of larger diameters. Pressure drops are much lower than for box aluminium and plastic systems.

Changing needs

The larger versions are suitable for ring or sub ring main use, while the 25mm and 16.5 sizes are ideal for branch networks or for drops direct to machinery, workbenches and air tools. Once installed, the system can be modified by the user with no specialist knowledge, making it particularly suitable for the changing needs of industry where new supplies of compressed air must be introduced to different workplaces with the minimum of downtime. Pipework is supplied in powder coated blue

In effect, Transair can be used straight from the compressor to the workplace, or as an immediate extension to an existing galvanised network.

The three and six-metre lengths of aluminium pipework are much lighter than galvanised steel, making them easier to handle on site and offering far greater opportunities to position the network at high levels. Flexible hoses are also available and enable the installation to be adapted further where building layouts demand.

The aluminium tubing which is to form the system is fixed into position by a snap-shut pipe clip and the network is then linked by instant push-to-fit connectors. These components are manufactured in engineering grade polymer and supplied ready for assembly. There is no need to tighten or untighten nuts as they are delivered screwed and aligned to their location marks for ease of insertion and installation. The connection is sealed and secured with just a simple push of the pipe into the fitting. A location mark on the tube also confirms that the connection has been made.              

Disconnection - perhaps to adapt the system further - is achieved with just a half-turn of the connector nut and the pipe can be removed. No tools are required for either operation.

Branching off the  system is achieved almost as quickly, with a unique “fool proof” pipe cutter and drilling kit which can be hired from the Transair distributor. The drill bit and jig are specially designed to ensure that the hole is cut quickly and easily, giving a perfectly clean, champhered cut. After drilling, the pipe is de-burred and connected with a locating pin ensuring that the bracket is easily centred into position.

Maximum versatility
Various types of bracket provide Transair with maximum versatility when changes must be made to the direction  of the system.

A quick assembly bracket is used to connect a main horizontal or vertical branch line, while more compact threaded mini-bracket allow the installation of a quick acting coupler with single passage - ideal for installing a flexible drop to a work station. A quick assembly reducing bracket is also available to connect, for example, a wall bracket from a 40mm main line via a 25mm diameter drop.
Continuing the clean air theme, Legris have integrated a preformed upward “swan’s neck” loop within the bracket to prevent the transfer of condensate from the main airline to the machine feed. There is consequently no need to spend time installing 180-degree bends as in traditional systems. Control of the Transair system can be achieved manually with just a quarter-turn of the Transair ball-valve, or remotely by using Legris’ compact self-actuating axial valve.

The system is also available in stainless steel, with all Transair pipework and components guaranteed for 10 years. Highly energy efficient, it qualifies for 100 per cent interest free loans from the Carbon Trust when used for compressed air.
Maximum working pressure for Transair is 16 bar, with operating temperatures from -20ºC to +60ºC. The system is totally compatible with Legris’ range of LF3000 push-in fittings, ball valves, couplers, tubing and blowguns.

Legris Limited
 Tel 01452 623500.
Fax 01452 623501.
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web: www.transair.legris.com