Yokogawa FU20/PH20 All-in-One pH/ORP Sensor - Manual (Page 7)

IM 12B6J3-E-H
3
3. INSTALLATION OF PH20
For optimum measurement results, the PH20
should be installed in a location that offers an
acceptable representation of the process
composition and DOES NOT exceed the
specifications of the sensor. The PH20 is
designed with threads on either end of the
body to allow installation via a selection of
adapters, in a wide variety of applications.
3-1. Typical Installation
The PH20 sensor is designed for in-line
installation, via a bypass loop as an immer-
sion assembly. For best results the PH20
should be mounted with the process coming
towards the sensor (see Fig 1) and positio-
ned at least 15° above the horizontal plane
to eliminate air bubbles in the glass bulb.
3-2. Preparing the Sensor for Use
Remove the sensor from its shipping box
and slide off the "wet pocket" (the tube filled
with solution to keep the measuring ele-
ments from drying out in storage or ship-
ment).
Two sets of O-rings are provided with the
sensor, a Viton set and an EPDM set. The
wet pocket is sealed on the sensor with (2)
Viton O-rings (K1511DP is 5 sets of 2 each
Viton O-rings). An EPDM set is supplied in a
plastic bag as an alternative (K1511DQ is 5
sets of 2 each EPDM O-rings).
IMPORTANT NOTICE
Before installing the sensor in the process it
should be calibrated. The calibration proce-
dure is normally described in the instrument
Instruction Manual, but a general Guide is
provided in Section 7.
3-3. Mounting the Sensor
Apply Teflon (PTFE) tape to the threaded end
of the appropriate adapter (step 2). Then
install the selected adapter (/FN4, /FR4,
/SNE, /SR3) in the process, tightening it by
applying a suitable torque using a spanner
on the adapter flats see Steps 1 & 3).
Next, screw the PH20 sensor into the adap-
ter making sure that there are (2) O-rings
mounted in the correct grooves (step 4).
These O-rings form a seal on the straight
section inside the adapter. This means that
the sensor needs only to be hand tightened,
(until the O-rings are completely covered) for
the seal to be completed (step 5).
NOTE 1:
DO NOT over tighten the sensor, as damage
may result.
NOTE 2:
Installing the PH20, requires approximately
seven turns. Take care, to leave enough
slack so that the cable is not twisted and
damaged.
If you are using one of the FF40, FS40 or
FD40 holders, simply screw the adapter
(/SF4) on the sensor body at the cable end
ensuring the O-rings are correctly installed.
See Section 6 for instructions to wire the
sensor to the instrument.
15º Minimum
5
t ape
2 3 1
4
Figure 1. Sensor Installation
Wrench
Flats
Teflon Tape
Process Flow
Do NOT
overtighten
Hand
tighten
Sealing
O-rings