Air Blast Cleaning System extends maintenance intervals.

Press Release Summary:

Auto Air Blast System blows jet stream of air for 1-3 min over dissolved oxygen sensor membrane at set intervals. Programmable timer in analyzer controls cleaning frequency, and compressor located near sensor provides air supply. Model 499ADO membrane dissolved oxygen sensor features molded Noryl construction and is suited for flow-through or submersion mounting. It incorporates integral temperature sensor and pressure-equalizing bladder.

Original Press Release:

Emerson's New Auto Air Blast Cleaning System Improves Dissolved Oxygen Sensor Reliability and Extends Maintenance Intervals

Proven in field testing, the new system extends cleaning intervals from weekly to four times per year

IRVINE, Calif., October 13, 2003 - The rigorous dissolved oxygen sensor maintenance schedule imposed upon wastewater treatment facilities has been cut from weekly to four times a year as a result of the availability of the new Rosemount Analytical Auto Air Blast System from Emerson Process Management. D.O. measurement is a critical step in the activated sludge process in aeration basins, which represent a high-coating environment and one of the most challenging applications for membrane sensors. To prevent coating, which renders sensors ineffective, manufacturers have traditionally recommended that sensors be cleaned as often as every week. Proven in field-testing, the Auto Air Blast System has been developed to help plant managers and operators meet their maintenance requirements faster and easier than ever before.

According to John Volbeda, water and wastewater industry manager of the Rosemount Analytical division of Emerson Process Management, "Today's plants are struggling to reconcile their need to conduct regularly scheduled maintenance with pressures to increase productivity in spite of fewer resources - without compromising quality. The new Auto Air Blast System is a solution to this struggle, as it enables plants to extend their limited resources cost effectively for maximum productivity."

The Rosemount Analytical Auto Air Blast System enables plants to overcome traditional D.O. sensor maintenance requirements as it blows a jet stream of air for one to three minutes over the sensor membrane at set intervals, such as every eight hours. The programmable timer in the analyzer can control the cleaning frequency, and a small high-efficiency compressor, conveniently located near the sensor, provides the air supply. This kind of air blast system cleans the sensor and eliminates the need for regular sensor removal from the process for weekly cleaning.

Field Test

Recently, as part of a five-month field test, three Rosemount Analytical Model 499ADO membrane sensors were installed at an Orange County, Calif., sanitation municipal wastewater treatment plant. All three sensors were placed near the outfall of the aeration basins. One sensor wasn't cleaned at all. One sensor was mounted on a floating ball, which affords the benefit of being easy to remove from the process for cleaning, but more specifically for the purposes of the study, was tested because it allows the sensor to make the measurement while reducing its exposure to coating elements. Some in the industry believe that the bouncing motion of the ball helps to clean the sensor. The third sensor was cleaned every 60 seconds for 8 hours using the Auto Air Blast System.

Regular visits were made to the site to conduct inspections of the sensors over the course of the study. Notably, by the second week, the only sensor functioning was the sensor cleaned with the Auto Air Blast Cleaning System.

About the Model 499ADO Sensor

Durable, reliable and easy to maintain, the Model 499ADO membrane dissolved oxygen sensor features rugged molded Noryl (PPO) construction and is suitable for flow-through or submersion mounting. An integral temperature sensor allows automatic correction for changes in membrane permeability caused by temperature. A pressure-equalizing bladder maintains correct membrane tension during fluctuations in sample pressure.

The Rosemount Analytical Model 499ADO sensor and Auto Air Blast System are available now.

About Emerson Process Management

Emerson Process Management (, an Emerson business, is a leader in helping businesses automate their production, processing and distribution in the chemical, oil and gas, refining, pulp and paper, power, food and beverage, pharmaceutical and other industries. A division of Emerson, Rosemount Analytical ( includes a Liquid Division in Irvine, Calif. that designs and manufactures analyzers, transmitters and sensors for the on-line measurement of pH, ORP, conductivity, dissolved oxygen, chlorine, ozone, suspended solids and turbidity. The best-in-class technology and expertise of Rosemount Analytical play a key role in Emerson's combination of superior products and technology with industry-specific engineering, consulting, project management and maintenance services. Emerson brands include PlantWeb®; Rosemount®; Fisher®; Micro Motion®; Ovation®; DeltaVTM; and AMS(TM) Suite

About Emerson

St. Louis-based Emerson ( is a global leader in bringing technology and engineering together to provide innovative solutions to customers in process control; electronics and telecommunications; industrial automation; heating, ventilating and air conditioning; and appliances and tools. Sales in fiscal 2002 were $13.8 billion.

PlantWeb, Fisher, Micro Motion, Rosemount, DeltaV ,Ovation, and AMS are marks of Emerson Process Management. All other marks are the property of their respective owners.


Emerson Process Management, Rosemount Analytical, Liquid Division: Jumana Sweis (949) 757-8536

Deborah Jones (714) 957-8880, ext. 113

Emerson Process Management:

Peter Dossing (512) 832-3162

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