A paradigm can be shifted (June 2012)
When a plant engineer has to purchase a compressed air dryer his first thought will likely be what dewpoint is required. This will then depend on the application; specifications of machinery using compressed air will guide the engineer as will codes of practice such as BRC/BCAS for the Food Industry. If a negative dewpoint is required then a desiccant dryer will be selected. The genre is likely to be well known to the engineer and will attract a significant capital and running cost particularly if a lower capital cost heatless dryer is selected. However the solution is classic and cannot be faulted.
The alternative scenario is for the positive dewpoint at typically +2degC and again the engineer will know that a refrigeration type dryer will handle this application with relatively low capital and running cost but that he must take care not to have pipework going below the dewpoint temperature.
Membrane type dryer
There is a third solution which is mostly ignored or perhaps is not fully understood. This is the membrane type dryer, and Beko Technologies offers its Drypoint M range of membrane dryers alongside its Everdry and Drypoint RA, desiccant and fridge dryers. Steve Riley, general manager of Beko Technologies in the UK and Ireland commented: “I was amazed at how many Drypoint M’s were being sold when I joined the company. A little research told me that 20,000 units had been sold since launch, in the UK alone. I could guess that many purchasers were ‘original equipment manufacturers’ because the main benefit I had in my mind was the very small footprint. I knew also that some compressor manufacturers had a packaged unit which included a membrane dryer but I couldn’t for the life of me guess the diversity of applications.”
He was correct in his thinking but later researches told him that there were very good reasons for engineers to select Drypoint M just on overall cost. This needs some explanation as what tends to put most engineers off is waste and membrane dryers can lose a quantity of compressed air in purge loss. However this is not fixed and Beko’s sales people have software that enables the choice of a low capital cost, higher purge loss unit or a higher capital cost and lower purge loss unit of energy cost is important (and when isn’t it).
Maintenance revenue
Riley added: “I don’t think anyone will be too surprised to know that one of the other statistics. I wanted to understand quickly was what maintenance revenue I would get from all these units. It was an unbelievable number – nothing, £0 – and it is not such a short-lived product that if a problem should occur it is more economical to throw it away. It is possible to destroy the membrane by having too much liquid ingress but Beko’s experience and design team have produced a dryer with close coupled separator and drain to protect against this eventuality. In fact there are no wearing or replaceable parts.”
|
Dryer type
|
Fridge
|
Heatless desiccant
|
Heat Reactivated desiccant
|
Zero Purge Heat reactivated
|
Membrane
|
|
£ Capital
|
Low
|
Low
|
Medium
|
High
|
Low
|
|
£ Installation
|
Low
|
Medium
|
Medium
|
Medium
|
Low
|
|
Footprint
|
Medium
|
Low
|
Medium
|
Medium
|
Low
|
|
£ energy
|
Low
|
High
|
Low
|
Low
|
Medium
|
|
£ Maintenance
|
Low
|
Medium
|
High
|
High
|
Zero
|
[Fig 1. caption) Beko comments that it is a mistake, certainly on smaller flows, to disregard the option of a membrane dryer.
Events
-
Smart Manufacturing & Engineering Week
05 - 06 June, 2024
NEC, Birmingham -
HILLHEAD 2024
25 June, 2024, 9:00 - 27 June, 2024, 16:00
Hillhead Quarry, Buxton, Derbyshire UK
