[compost_tea] FW: Hach LDO Meters

From: Judi Stewart <js_at_olympus.net>
Date: Sat, 15 May 2004 08:52:38 -0700

Terrance Dodge emailed me this information about the
new Hach LDO meters. The price hasn't been listed.
 
Judi

 
"The Hach Dissolved Oxygen (LDO) probe works quite differently from the
galvanic and polarographic methods which have been used for more than 50
years. There are no membranes, no anodes or cathodes and no electrolyte
solutions. Maintenance consists merely of wiping the sensor with a wet
rag!
 
The LDO probe has an inexpensive replaceable sensor cap which is
guaranteed for one year. The sensor cap is coated with a luminescent
material. Blue light from an LED is transmitted to the sensor surface.
The blue light excites the luminescent material. As the material relaxes
it emits red light. The time from when the blue light was sent and the
red light is emitted is measured. The more oxygen that is present, the
shorter the time it takes for the red light to be emitted. This time is
measured and correlated to the oxygen concentration. Between the flashes
of the blue light, a red LED is flashed on the sensor and used as an
internal reference.
 
Calibration is not necessary. Because the sensor is not affected by pH
swings, hydrogen sulfide, wastewater chemicals or heavy metals, the Hach
LDO probe produces more stable and accurate measurements for a longer
time.
 
Warm-up time is not necessary - just turn the analyzer on and start
measuring. Once the analyzer is on, it responds quickly, giving readings
in less than 60 seconds. It provides accurate readings, even with
organic build-up on the sensor. The analyzer can have dual inputs and
outputs.
 
The advantages of the Hach LDO are reduced maintenance, infrequent
calibration, simple operation and replacement, all combined with
accuracy, stability and speed. The technology used to achieve this
represents a world-wide break through in the measurement of dissolved
oxygen."
 

 







Received on Sat May 15 2004 - 13:14:05 EDT

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