Yokogawa PH18 Differential pH Sensor User Manual

Page 12

IM 12B6J4-E-A

Example A. Straight weld-in adapter through a vessel
wall.
Example B. 1” Screw-in adapter with existing pipe
nipple through a vessel wall.
Example C. Angled weld-in adapter in large bore pipe.
Example D. Angled weld-in adapter mounted in a
bend
Example E. Screw or weld-in adapter mounted in a
large bore pipe.
Example F. Screw or weld-in adapter mounted on top

Fig. 11 The primary adapter is used to make a
connection to the process used by the transmitter as
the liquid earth (solution ground). This is needed for
optimum stability of the measurement and is used in
the impedance checking circuit.

Note 1:
When measuring in plastic tanks or pipes, ensure that the adapter is
wetted by the process. Avoid installations where an air pocket can
be created (see fig 12 F). This isolates the adapter, and hence loses
the liquid earth connection.

Note 2:
Flow rate from the side of the sensor (Fig 11) should not exceed 2
meters/second in low viscosity fluids. In high viscosity fluids (> 5cP)
use only installation as
shown in Fig. 12 (D).

Fig. 12. Model 18 elements

IM 12B6J4-E-A

3-5. PH18 Installation examples

Note 1:
When measuring in plastic tanks
or pipes, ensure that the adapter is
wetted by the process. Avoid
installations where an air pocket can be
created (see fig 12 F). This isolates the
adapter, and hence loses the liquid earth
connection.
Note 2:
Flow rate from the side of the sensor (Fig
11) should not exceed 2 meters/second
in low viscosity fluids. In high viscosity
fluids (> 5cP) use only installation as
shown in Fig. 12 (D).

Example A. Straight weld-in adapter

through a vessel wall.

Example B. 1” Screw-in adapter with

existing pipe nipple through a
vessel wall.

Example C. Angled weld-in adapter in

large bore pipe.

Example D. Angled weld-in adapter

mounted in a bend

Example E. Screw or weld-in adapter

mounted in a large bore pipe.

Example F. Screw or weld-in adapter

mounted on top of a large
bore pipe

Fig. 11 The primary adapter is used to

make a connection to the process used by
the transmitter as the liquid earth (solution
ground). This is needed for optimum
stability of the measurement and is used in
the impedance checking circuit.

Socket for connection

cable

Primary adapter

pH enamel

Reference enamel

Fig. 12. Model 18 elements

3-5. PH18 Installation examples