YOKOGAWA PH8ECP, User Manual, Page: 21 / 27

< 3. USE OF pH SENSOR >
3-2
IM 12B7J3-01E
3.1.3 Replenishment of KCl Solution
When the KCl solution in the tank seems to be nearly exhausted while using a pH sensor with general
type reserve tank, replace the reserve tank with new one (provided separately as spare part). Instead
of replacing the reserve tank, it can be replenished with a prepared KCl solution. Dissolve 246 g
powder deionized water and dilute to one liter to make an approximately 3.3 mol/L KCl solution.Put
the solution in the tank, taking care not allow the KCl solution to spout from the vent hole of the tank.
When a pH sensor with a medium pressure reserve tank is used, replenish the KCl solution when the
KCl solution in the tank seems to be nearly exhausted. Carry out replenishment of KCl solution as
follows:
(1) Close the valves to shut off the flow or measured solution (see Figure 3.1), first in the inlet then
the outlet valves in the flow-through type holder.
Outlet
Stop valve
Inlet
Stop valve
F3.1E.ai
Figure 3.1 Process Piping of Flow-through Type Holder
(2) Remove the socket type connector on the reserve tank and stop the air pressurizing the tank
(see Figure 3.2).
F3.2E.ai
Socket type Connector
Press this part,
connector can be removed.
Figure 3.2 Socket type Connector
(3) Remove the nut fixing the reserve tank cap and remove the cap.
7th Edition : Nov.20,2018-00