YOKOGAWA TB820D, User Manual, Page: 29 / 87

<2. INSTALLATION, PIPING, AND WIRING>
2-18
IM 12B01B30-02EN 2nd Edition : June 09 , 2021-00
4. To prevent clogging or stagnation of air bubbles in the pipe line, install the pipes so that no
bends or stagnation occurs.
(2) Piping of the Sample Line from the Detector
This piping is for draining a sample from the measurement cell of the detector during
measurement. As shown in Figure 2.25, connect a needle valve to the sample outlet of the
detector. By adjusting the opening of this needle valve, the pressure change in the piping
between the sampling point and the detector outlet is controlled, and thus the generation of air
bubbles is prevented.
1. To the sample outlet of the detector, connect a fitting, such as an elbow fitting,
corresponding to the connection size (Rc1/2 or 1/2 NPT female) and a needle valve.
2. To the outlet of the needle valve, connect a fitting corresponding to the valve connection size
and a hose/tube that can withstand the flow and the pressure of a sample. Route this hose/
tube to a drain pipe.
3. As shown in Figure 2.25, the sample from the detector should be discharged to the
atmosphere at a point higher than the measurement cell of the detector. If no, a siphon may
be created and the measurement cell may not be filled with a sample. In addition, if the
sample inflow stops, the sample will be drawn off and the measurement cell will be emptied,
which can cause damage to the ultrasonic transducer, if used.
(3) Drain Piping
This piping is for draining a sample from the measurement cell of the detector during cleaning,
calibration, or other maintenance.
1. The drain of the detector is Rc1/2 (or 1/2 NPT female) thread. Install a fitting corresponding
to the thread and connect a hose/tube with sufficient diameter that provides adequate flow
of sample, to route the sample from the detector to a drain pipe. Take care to install the pipe
so that no stagnation occurs.
2. As shown in Figure 2.25, install a pipe so that the sample drained from the detector to the
drain pipe.
(4) Piping of the Zero Water Line
This piping is for introducing tap water passed through a zero turbidity filter, to the detector for
zero calibration or measurement cell cleaning.
1. As shown in Figure 2.25, install a tap water valve and a zero water drain valve.
2. Connect a zero water supply valve to one end of the 3-way tee fitting attached to the sample
inlet of the detector.
3. Install a fitting corresponding to the piping connection of the zero turbidity filter and connect
an hose/tube that can withstand the pressure of tap water, such as a rigid PVC tube. The
flow rate of zero water supply should be in the range of 1 to 3 L/min.
4. For the specifications of the zero turbidity filter, see “1.3 Specifications”
5. To prevent corrosion of water inside the zero turbidity filter, allow water to flow through
the filter and flow out from the zero water drain valve continuously at a flow rate of
approximately 10 mL/min.