MODEL DO-03/04 | SECTION 1.0 |
| SPECIFICATIONS |
SECTION 1.0
SPECIFICATIONS
•COMPLETE SYSTEM INCLUDES sensor, analyzer, sensor washer head, mounting hard- ware, and air compressor.
• AIR BLAST CLEANER system can keep DO sensors funtioning up to 3 months or longer.
•SENSOR MAINTENANCE is quick and easy.
•FEATURE-PACKED ANALYZER: on-board pressure sensor for completely automatic air calibration, large backlit display, dual outputs, three fully programmable alarm relays.
FEATURES AND BENEFITS
The Model DO-03/04 is a complete system for the determination of dissolved oxygen in wastewater aeration basins. It consists of a sensor, an analyzer, a handrail mounting assembly, a sensor washer head, and an air compressor. A timer in the analyzer allows the user to customize the air blast cleaning cycle.
The Model DO-03/04 uses a membrane-covered amperometric sensor. A polarizing voltage applied to a gold cathode behind the membrane destroys oxygen diffusing through the membrane and keeps the concentration of oxygen in the sensor equal to zero. The current generated by the cathode reaction is proportional to the rate of diffusion of oxygen through the membrane. Because the concentration of oxygen in the sensor is zero, the diffu- sion rate and the current are proportional to the concentration of oxygen in the sample.
Sensor maintenance is fast and easy. Replacing a membrane requires no special tools or fixtures. A screw cap holds the pre-tensioned membrane in place. Replacing the electrolyte solution takes only minutes.
The Model DO-03/04 includes the rugged, easy-to-use Model 54eA analyzer. The analyzer features two fully pro- grammable 4-20 mA outputs, and three fully programmable alarm relays. The backlit three line display allows the user to read oxygen levels at a glance. The analyzer permits both air calibration and calibration against a labora- tory instrument. Air calibration is completely automatic. All the user does is expose the sensor to water-saturated air and press a few buttons.
The Air Blast Sensor Cleaner, which includes the washer head and air compressor, keeps the sensor membrane clean, helping ensure reliable, trouble-free oxygen measurements and reducing sensor cleaning maintenance to as little as every three months. At programmed intervals, the air blast cleaner blows a stream of air across the membrane to clear bio-film from on the membrane. The frequency and duration of the air blast is programmable from the 54eA analyzer.
The photograph shows a sensor after nine weeks in an aeration basin. The cathode is clearly visible under the membrane. A 60-second air blast every eight hours is keeping the membrane clean.
Plant service air can be used in place of the air compressor. The 54eA analyzer relay is then used to operate a solenoid valve.
