Application Notes

The Problem – Stable Furnace Draft Pressure Measurement

If you are running a steel mill or glass plant, much of your operating expenses are in energy costs. The fuel required to melt large amount of steel or glass is not trivial. Also, too much fuel or too little air and your furnace starts to smoke, triggering environmental concerns. The optimum mixture of fuel and air must be maintained in the combustion chamber for the best efficiency and lowest costs.

The amount of air introduced into the combustion chamber is typically controlled by the position of a large damper. The difference in pressure between the inside of the combustion chamber and the outside ambient atmosphere is what determines the damper position. A very slight negative pressure, perhaps as little as 0.05 In H2O, is maintained to provide the optimum flow of air into the combustion process.

The pressure transmitter used to make this measurement must have several exacting performance characteristics:

  • Sensitivity to Low Pressures
  • Ability to Provide a Stable Signal
  • Little or no Change in Output as a Result of Severe Ambient Temperature Changes

The Solution – VR Sensor Technology

Variable reluctance technology provides for sensors whose full-scale pressure ranges are as low as 0.1 In H2O. Competing technologies often over-amplify a sensor whose range is much higher than the furnace draft measurement requires. Because the gain is lower for a variable reluctance sensor, its performance in ambient temperature change is typically ten times better than others. In the rugged industrial environment of a steel mill or glass furnace, Validyne products have the edge in reliability and performance.

Validyne Products – The DR800

The Validyne DR800 Draft Range Transmitter was designed to meet the challenges of industrial furnace draft measurement. The DR800 is available in full scale ranges as low as 0.1 In H2O, and the zero elevation and suppression feature allows the industry standard offset calibrations to be easily supplied. In addition, the output filter time constant of the DR800 may be set to as much as 8 seconds. A rugged enclosure completes the best draft range package available.

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Phone: 818.886.2057 || Email: Sales@validyne.com