Open end to atmosphere

20 June, 2014

All of these combine to ensure that the condensate volumes are different from day to day, morning to evening, winter to summer, UK to China. Product of choice To be sure to get rid of the condensate then the blow down time will be set for the worst case, which will mean considerable wastage on every occasion that does not equate to this set time. The solution to this is the zero loss drain, which is becoming the product of choice because there are no losses of the expensive resource of compressed air. There is an investment cost but in nearly all cases the return on investment can be shown as being acceptable. There may be as many as 100 drain points in a large plant with outdoor piping so it is a simple but important area to consider for the maintenance routine. A customer in the Midlands recently asked Beko Technologiess to attend site because of a perceived drying problem. This problem existed and was being dealt with but as part of the routine checks the air receiver drain was checked. With no exaggeration 15 minutes was required to drain the large air storage vessel. If the condensate level had become much higher than serious amounts of the contaminated condensate would have been re-entrained into their system. The company are involved in an industry where it is vital to be ‘just in time’ and deliver direct to production lines. It is easy to imagine the large scale problems for this company and its customers if a large scale ingress of condensate had occurred. The installation of an efficient level sensing Bekomat solves a potentially disastrous situation at a small investment cost The other area where compressed air is wasted is in the drying process. There are many processes which require a dew point below the -3degC, which refrigeration dryers are capable of reaching. This could be for instrument air, for pneumatic conveying, food, beverage or medical grade compressed air to name a few processes. The lower dew point typically -40degC is achieved by use of a desiccant material which is unchanged by the process of attracting water vapour via molecular forces but will need to be regenerated in order to be used over multiple drying/regenerating cycles. One of the regeneration methods is heatless or cold regeneration which requires a part of the dried compressed air to be expanded to become super dry and then flowed through the wet desiccant bed. Nature does not like large gradients and the difference between the water content of the desiccant and the regeneration air will create the migration across to the compressed air which is then vented to atmosphere. In this method 15 per cent of the compressed air is used solely for drying which if we equate back to our 75kW compressor would mean a cost of £10,000 or more. The reason this genre of dryer was popular was because of low price and simplicity but it is clear that for systems above the 75kW level other methods should be applied. Controlling cost Zero Purge dryers are becoming the norm for larger installations. They use external heat to regenerate the desiccant and blown external air to cool meaning that the costs are kept to a sensible level for the drying process. An example given at Air-Tech was of a company in the automotive industry who had a part purge drying system so lost a smaller notionally 5 per cent of the compressed air but had heating costs and cooling costs. The offer of a zero purge system showed a payback of

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