Analyser Systems: “To Pump or Not to Pump…”

In the design of continuous analyser systems many strategic decisions must be made to achieve optimal convergence of performance, cost and reliability. For those systems that have low or negative pressure, a choice between a mechanical pump or eductor must be made.  Choosing to use a pump will necessarily undermine two of the three legs - cost and reliability. Mechanical pumps have significantly higher installation and capital cost, especially when exotic metals or hazardous areas are involved. Moving parts lead to decreased reliability and increased maintenance.

Normally, an eductor is a better choice. Advantages include: Simple design; Reliability – no moving parts; No maintenance required; Intrinsically safe; Low cost; Easy to install; Compact; Powered by air, nitrogen, process fluid, water etc; Tolerant of liquid droplets and small particles; Operates at elevated discharge pressures, e.g. flare return; and Used for sampling, mixing, vacuum, venting. 

Always select a mini-eductor with high efficiency, such as the Motiv-Air-Torr, that delivers higher vacuum and sample flow at lower motive pressure, saving on operating cost.