Venturi steam traps minimise steam loss

Venturi orifice steam traps, fitted to feedwater heat exchangers, air heater batteries and distribution lines, are minimising steam loss at a UK food manufacturing plant.

Gardner Energy Management's (GEM) Venturi orifice steam traps are minimising steam loss at Kraft Foods site in Banbury.

Fitted to feedwater heat exchangers, air heater batteries and distribution lines, the GEM steam traps are operating over variable loads with a turndown ratio on the heat exchangers of 3:1.

Kraft Food's Banbury site boasts the world's largest soluble coffee facility, manufacturing coffee for the global Kraft business as well as UK household brands such as 'Kenco', 'Maxwell House' and 'Mellow Bird's'.

The site produces some 11 billion cups of coffee a year and also houses the company's leading research and development facility.

The company raises some 40 tonnes of steam an hour costing around GBP 6.5 million/year.

Although steam is utilised throughout the site it is principally used in feedwater heat exchangers feeding the extraction sets.

Kraft operates banks of heat exchangers, which handle a total of between 6,000 and 45,000 litres of water/h.

A total of 120 steam traps are used throughout with site with the majority of mechanical steam traps having now been replaced by the GEM Venturi orifice trap.

Conscious that existing mechanical traps were failing, resulting in lost steam and reduced plant performance, John Weir, utilities manager at Kraft Foods decided to investigate Gardner Energy Management's patented GEM steam trap and asked the company to carry out a site survey.

The report from Gardner Energy Management explained that by replacing the existing traps with the GEM venturi orifice design, blocked steam traps could be prevented from impacting on production and by efficiently returning condensate back to the boilers energy savings would be made.

The GEM steam traps work by using the difference in density between steam and condensate.

Steam is 1000 times less dense than condensate, so at the entrance of the trap's orifice, the low-density steam is literally squeezed out of the condensate.

The high density, low moving condensate is then preferentially discharged through the orifice, trapping the low-density steam behind it.

What makes the GEM trap different is its venturi orifice configuration, which works well over varying loads by using the 'flash' steam that comes out of condensate as it passes from high to low pressure to give a self-regulating, varying capacity.

As the GEM steam traps have no moving parts to wedge open or fail, it provides the ultimate in reliability necessitating only minimal maintenance and requiring no spares, testing or monitoring equipment.

"The GEM steam traps perform well over a wide range of loads," said Weir.

"In addition to saving down time with maintenance and replacement traps, the GEM traps have provided us with a short term payback through energy savings from steam wastage." He is particularly pleased that as the traps are individually sized dependent on load and up and downstream pressures, if there are any problems GEM will replace the trap until the duty is correctly matched.

This is useful where exact loads may not be known.

Such has been the success of the GEM traps that they have been specified for Kraft Foods leading research and development facility also located at Banbury.

Back to top