PROBE & MEMBRANE MAINTENANCE
11
10. PROBE & MEMBRANE MAINTENANCE
The D.O. probe body is made of reinforced plastic for maximum
durability.
A thermistor temperature sensor provides temperature
measurements of the tested sample. It is always recommended to
keep the protective cap on the probe when not in use, to protect it
against damage and dirt.
To replace the membrane
or refill it with electrolyte, proceed
as follows:
y
Remove protective cap by gently twisting
and pulling it off the probe's body.
y
Unscrew the membrane by turning it
counterclockwise with the other hand.
y
Wet the sensor by soaking the bottom 2.5 cm
of the probe in electrolyte (
MA9071
) for
5 minutes.
y
Rinse new membrane supplied with meter
with electrolyte, while shaking it gently.
Refill with clean electrolyte.
y
Gently tap the sides of the membrane with
the finger tip to ensure that no air bubbles
remain trapped. Do no directly tap the
bottom with the finger as this will damage
the membrane.
y
Make sure that the rubber O-ring is seated
properly inside the membrane cap.
y
With the sensor facing down, screw
the membrane cap clockwise. Some
electrolyte will overflow.
If the Platinum cathode is tarnished or stained, which could be
due to contact with certain gases or to an extended use with a
loose or damaged membrane, it should be cleaned.
Use a clean lint-free cloth and rub the cathode very gently side
to side 4-5 times. This will be enough to polish it and remove any
stains without damaging the Platinum tip.
Afterwards, rinse the probe with deionized or distilled water and
install a new membrane cap using fresh electrolyte and follow the
steps above. Recalibrate the instrument.
TWIST
AND
PULL
UNSCREW
SILVER
CHLORIDE
ANODE
SILVER
CHLORIDE
ANODE
PLATINUM
CATHODE
OXYGEN
PERMEABLE
TEFLON
MEMBRANE
