- Closed - causing water-logging, corrosion and in some cases water hammer, or
- Open - leaking live steam and energy.
Additionally when such traps fail open and discharge into condensate return systems, they cause pressurisation of the condensate lines which inhibits trap drainage and often reduces heat output and hence productivity.
Over the last decade a new type of steam trap with no moving parts has gained UK market acceptance in overcoming these operational problems. As it has no parts to fail or wear out, its use obviates the need for continual trap testing, repair and replacement.
Like all previous types of orifice trap, the ‘GEM Trap’ uses the condensate within its orifice to hold back steam, rather than any valve arrangement. However, unlike previous orifice plate traps, it is claimed that a unique staged venturi allows the trap to operate efficiently over the varying load conditions that predominate in industrial steam systems. The operating principle is to use the flash steam emitting from the condensate as it discharges through the venturi to provide a local back pressure to regulate flow. This principle is described by a demonstration program on the manufacturer’s web site www.gemtrap.com. However the purpose of this analysis is to test this theory by measuring the comparative efficiency of the GEM trap over variable loads.