Dear sir
Re; October issue: Traps for the unwary
Dr Neale’s timely article in the October issue gave an excellent description of all the different types of mechanical steam traps. He also quite rightly highlighted that steam traps are all too often the cause for an unnecessary 10 to 15% rise in fuel consumption.
He estimates that for a typical laundry with a £70 000 annual fuel bill, the steam loss through traps is likely to cost £20 000, “which some laundries seem quite prepared to accept”.
High fuel prices With the highest fuel prices in ten years, Climate Change Levy on the horizon and a very competitive market, only the foolish would not want to grab that £20 000 for their bottom line. It could easily mean the difference between profit or loss for years.
If only it were that simple.
As many a steam specialist will stress, these steam losses can be recovered by testing your existing traps and replacing the faulty ones. If it is that simple, then, why do we not hear of the great steam trap rush? The reason is, as all steam engineers will point out; l as soon as you have your traps tested, the report is out of date as the next day another trap is likely to have failed; l once you replace the faulty traps, or even if you replace all your traps, they start to progressively fail again.
This is a good situation if you charge for surveys and make traps for a living but it is not good news if you have to face ever increasing fuel bills each month.
So what is the answer? The answer is the Venturi orifice steam trap and this is supported by two documents.
Firstly, September’s LCN article “Saving Money” which reports the first-hand experiences of Leighton Hospital laundry managers in permanently overcoming their steam losses with Venturi orifice traps.
Secondly, the DETR’s Energy Efficiency Best Practice Programme has just published ETSU’s case study 120 on the performance of GEM Venturi orifice steam traps at Withington Hospital laundry.
ETSU independently monitored the steam consumption before and after a wholesale replacement of the mechanical traps to Venturi orifice traps. The permanent 19% steam saving equated to a £10 000 annual steam saving in 1998. So, as fuel costs have more than doubled, this correlates with Dr Neale’s more up-to-date figure of £20 000. The case study also reports maintenance savings and no trap failures, reinforcing his statement that orifice traps have “no moving parts and theoretically nothing to go wrong”.
Unfortunately, Dr Neale’s article is misleading in that it simply refers to the ‘orifice trap’ and does not state the type of orifice trap to which he refers.
In the 1960s the orifice-plate trap, with no Venturi configuration, was launched onto the market. It was not successful as it had a fixed capacity and tended to leak live steam at low loads.
This does not happen with the Venturi type and ETSU’s independent case study would not have reported such impressive savings as it did in a laundry with constantly varying loads.
Furthermore, as steam users are all too aware, steam loss though traps pressurises condensate pipework and this back pressure reduces the heat output of ironers and dryers.
The experience of Venturi orifice trap users and the findings of case study 120 show increased output from more effective condensate drainage and a permanent solution to back pressure from failed traps.
Perhaps Dr Neale could therefore clarify the type of orifice trap to which his statements refer and what experience, if any, he has with Venturi orifice traps.
In the meantime, the Energy Efficiency Best Practice Programme, case study 120 can be downloaded from www.eebpp.com alternatively call Christine Westgate of GEM Ltd. on 0117 9077377 for a hard copy.
