Yokogawa pH/ORP Retractable PH97 - Manual

PREPARATION FOR USE:
1. Remove storage boot containing the
storage solution (3.8M KCl) by unwind-
ing the black sealing tape from the sen-
sor housing.
NOTE:
DO NOT remove the wetted fiber pack
from inside the storage boot.
2. Save the storage boot with fiber pack
for future use as a storage container
and bulb protector when sensor is not in
service. Be certain to use 3 to 4 M KCl
as the storage solution. Seal boot to
sensor with black electrician’s tape
using 3 to 5 complete wraps.
3. For first-time use after removing the
storage boot: Inspect the sensor for any
signs of breakage or shipping damage
and commence with Calibration Proced-
ures.
4. For sensors with replaceable o-ring
seals: All o-rings require proper lubrica-
tion. We recommend use of PARKER O
LUBE or equal for this purpose. Follow
the instructions provided with lubricant.
For best results we recommend that all
o-rings be replaced whenever sensor is
removed for service or inspection.
CAUTION:
The Model PH97/DP pH sensor is de-
signed for use only with the Model PH87
retractable assembly. Please refer to the
Model PH87 retractable assembly install-
ation manuals for complete assembly,
installation, and service instructions.
CALIBRATION PROCEDURE:
Refer to the specific instructions for pH
sensor calibration described in the
instruction manual provided with the
EXA pH analyzer. These instructions will
include procedures for automatic and/or
manual calibration.
For best results it is recommended
to perform a two-point pH calibration
using NIST primary buffers.
Recommended Two-Point
Calibration:
Rinse the probe thoroughly with DI
water to remove all traces of storage
solution, process medium or previous
test solution to prevent “carry over” con-
tamination of the pH buffer solutions.
Thoroughly rinse the probe with DI
water after each buffer test.
NOTES:
• Always use “fresh” pH buffer solutions
for best results.
• pH buffer solutions above 7.0 pH are
less stable and have a very limited life.
These high pH buffers will more readily
absorb CO
2
from the atmosphere and
will typically change to a lower pH value
when left open.
• Keep in mind the the “older” a sensor
becomes, it will exhibit slower response
times and will become less efficient in
terms of its ability to span several pH
units with the same repeatability.
CLEANING A MODEL PH 97/DP
WITH IMPAIRED RESPONSE:
Used pH sensors which are physically
intact can sometimes be restored to an
improved level of performance. All pH
sensors have a given useful life span
depending on the conditions of use. One
of the following procedures may prove
helpful in restoring a used pH sensor.
1. Initial Cleaning: Wash with a solu-
tion of liquid detergent or enzyme deter-
gent and warm water by gently scrub-
bing with a soft toothbrush or soft tissue.
Follow with thorough rinse in DI or clean
tap water.
2. Inorganic Scale Deposits: Dissolve
the deposit by immersion of the sensor’s
measurement tip in dilute hydrochloric
acid for a few minutes. Repeat step #1
above.
3. Organic Oil or Grease Films: Per-
form initial cleaning procedure. If film is
known to be soluble in a particular org-
anic solvent, wash with this solvent.
Repeat step #1 above. Depending on
the extent of the oil or grease contami-
nation, it’s possible that the liquid junc-
tion may be damaged beyond recovery.
Soak in 3 to 4M KCl solution for a mini-
mum of 30 minutes before recalibration
and returning sensor to service.
4. Plugged or Dry Liquid Junction:
Remove any observed contaminant with
one of the above procedures, then soak
in 3 to 4M KCl solution for a minimum of
30 minutes.
NOTES:
• Never permit the pH sensor to dehy-
drate or dry-out. Always keep it in a wet-
ted environment especially when not in
service.
• Cracked or broken sensors are not
repairable.
•
Inspect cable and connector to en-
sure that the insulation integrity is intact
and that there are no signs of corrosion
or contaminants on the metal compo-
nents.
STORAGE:
1. Short Term: Immerse sensor meas-
urement tip and liquid junction surface
areas in 3 to 4M KCl. If this solution is
not available, use 4.01 pH buffer, clean
tap water, or lastly, a sample of the pro-
cess being measured to keep the sen-
sor hydrated.
2. Long Term: Fill storage boot that the
sensor was originally shipped in with a
freshly prepared 3 to 4M KCl solution
and insert sensor. Seal boot to sensor
with black electrician’s tape using 3 to 5
complete wraps. The sensor should be
stored in an upright (vertical) position.
Instruction
Sheet
DynaProbe ®
Model PH97/DP
pH Sensor
Yokogawa Corporation of America
2 Dart Road, Newnan, GA 30265
Tel.: 770-254-0400 Fax.: 770-251-6427
U.S. Patent 5,147,524
®DynaProbe is a registered trademark of
Broadley-James Corporation
Doc. Nr. L2531