Feature Compressed air Get your compressor site just right
Huge energy and carbon savings can be achieved by investing in a new, modern compressor, but it’s important to consider where it will be sited, and if the pipework needs updating – as this can have a significant impact on efficiency. Andy Jones, Mattei general manager, explains
A
lthough some compressors are housed in purpose-built, con- trolled plant rooms, it is just as common for them to be sited on
the factory floor. While this is entirely acceptable, factory managers need to be mindful that environmental factors can affect a compressor’s efficiency, performance and wear and tear. The main consideration is air flow into the compressor. It is important to avoid installing a compressor near to any heating equipment or source of heat. The air entering a compressor should be as cool as possible, as being denser, it is more efficient. If the air being drawn into the compressor is warm, the machine must work harder, reducing its efficiency as well as the lifetime of its parts. Cool air also helps ensure a compressor doesn’t overheat. Secondly, the compressor should be sited away from sources of solid and gaseous impurities, as the air being drawn into the compressor needs to be reasonably clean. This can actually be straightforward; it might simply mean rotating the compressor so the air intake isn’t subjected to dust or fumes. Of course, if this isn’t possible then additional filtration can be used. Thirdly, there must be a sufficient volume of air to serve the compressor. Air flow should be unrestricted and where intake ducting is used it should be of a sufficiently large cross sec- tional area to avoid excessive pressure drops. A pressure drop of 10 millibar reduces flow by one per cent.
If housed in a plant room the air vent must be large enough to supply an adequate volume of air. In some fac- tories the door to the plant room is continually left open in an attempt to ensure there’s enough air circulating around the compressor, but even this might not provide suitable air flow, and could lead to pollutants being drawn into the air intake filter, block- ing it prematurely, as well as the risk of unauthorised access to equipment that is often critical, and expensive. Before a new compressor is installed
it’s important to re-evaluate the exist- ing pipework and system design, making changes and investing in upgrades where necessary.
The distance between the compres- sor and where the compressed air is actually used can have important implications, so should be assessed, especially if machinery or production lines have been relocated. Pipe runs should be suitably sized for the air delivery capacity of the compressor/s, with bends kept to a minimum. For systems where the point of use and the compressor are close then a single line could be chosen, whereas for larger systems with many points of use a ring main is preferable. When new energy efficient com- pressors are installed the pipework isn’t always upgraded, and in some cases it’s not even inspected for leaks and damage – meaning any energy efficiency benefits could be negated. In many companies in excess
Where your
compressor is sited can have a major impact on energy savings
of 30 per cent of air generated is wasted through leaks in the system – so it would be entirely false economy to install a new, energy efficient com- pressor without firstly fixing any leaks that might exist. As a guide, for a com- pany using 50m3 of compressed air per minute we estimate annual savings from fixing leaks would potentially be around £63,000.
A company could save thousands of pounds a year as a result of fixing compressor leaks
Mattei’s Maxima is a range of rotary vane compressors designed to meet the needs of those installations where compressed air demand is constant and continuous
Existing pipework might also be damaged, altering the efficiency of a system. If pipework is being replaced aluminium could be considered a more preferable material; it has good properties in terms of minimising fric- tion and reducing energy losses, and is generally easier and quicker to install. With the UK’s focus on energy effi-
ciency, it is possible a new compressor installation will also include heat recovery, perhaps for the delivery of hot water. This needs careful consider- ation if it is to be an efficient addition to the system. If the hot water is, for example, used across the other side of the factory to where the compressor is sited, it isn’t going to be efficient. To achieve optimum savings new compressors should be sited cor- rectly, and the pipework and system layout suitably designed. We recommend a site assessment and audit are carried out before any new compressor is installed, to identify and rectify any issues. Mattei
www.mattei.co.uk
T: 01789 450577 Enter 322
Compressor solution saves insulation board firm £6,000 a year
n a bid to meet production demands for improve- ments in energy efficiency and air quality, Suffolk based insulation board manufacturer Celotex has replaced its compressor installation with an Atlas Copco full-feature, variable speed drive, oil-free com- pressor together with a heat regenerative IMD dryer. This reduced energy consumption and improved air supply quality in the plant and the environmental impact has been a contributory factor in gaining the company its ISO 14001 accreditation. Dry compressed air is an essential factor in the continuous production process for insulation board assembly, which sandwiches PIR foam (polyisocyanu- rate) between two layers of aluminium foil or mineral glass tissue facer. Two existing Atlas Copco ZT37 fixed
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speed, oil-free compressors and associated refrigerant dryers were replaced with a single air-cooled ZT75VSD FF machine incorporating an IMD heat-of-compression technology dryer. The installation provides the com- pletely moisture-free air blanket required for the pro- duction process and, its variable speed drive feature that matches output to production demands, is a major
Factory Equipment JANUARY 2012
factor in reducing energy consumption. Celotex process improvement manager Jason Walker, says the company can expect energy savings of around £6,000 a year. Atlas Copco’s Full Feature concept is a total instal- lation − the compressor is a pre-wired and pre-piped solution. Integrating the IMD dryer and its variable speed drive enables the compact package to supply high quality dry compressed air at the lowest cost. The IMD absorption dryer eliminates the moisture before it enters the air net to ensure a reliable process and a contamination-free end product. No external energy is needed to dry the air, and as the dryer needs no purge air, no compressed air is wasted. Atlas Copco
www.atlascopco.co.uk
T: 01442 261201 Enter 323
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