Hach Lange 2100AN, Instrument Manual

Page: 55 / 108

SECTION 5,
continued
55
The discharge end of the drain tube must be unrestricted and lower than the
instrument to prevent air locking and ensure proper drain flow. Locate the
instrument as close to the drain as is practical using the shortest length of
drain tubing possible.
The kit is supplied with 152 cm (5
′
) of
1
/
4
" tubing. The system will not drain
properly if this length is exceeded. If the entire 152 cm is used, the end of the
drain tubing must discharge at a point at least 46 cm (15") below the center
line of the instrument to ensure proper flow.
6. Connect the power supply to the Power jack on the Flow Valve Module.
Plug the power supply into an appropriate wall receptacle.
7. Connect the Remote jack on the back of the 2100AN Turbidimeter to the
Remote jack on the back of the Flow Valve Module using the remote cable.
5.2.2.2 Using the Automated Flow-Cell Kit
Note: Assemble the Flow Cell,
tubing and stand. Then, fill the
system with water to ensure all
connections are water tight before
inserting the Flow Cell into the
sample compartment of the
instrument. Once filled, inspect the
system for leaks. Also, make sure
the cell is clean, and there are no air
bubbles present. Air bubbles tend to
collect in areas that are not cleaned
thoroughly.
Thoroughly clean the Flow Cell (refer to Section 5.2.5 on page 63), and then apply
a thin coat of silicone oil to the outside of the cell (see Section 2.3.2.1 on page 19).
Install the Flow Cell in the sample compartment, and press the inlet and outlet
tubes into the slots provided on the instrument's top enclosure (see Figure 11).
Cover the cell with the Flow-Cell Light Cover.
The Flow-Cell Light Cover must be installed at all times when the Flow Cell is in
use. The instrument's cell cover does not close when the Flow Cell is installed.
Manual flow through the Flow Cell is controlled by using the valve-control switch
on the Flow Valve Module. The valve control is a three-position switch:
Continuous Open, Closed, and Momentary Open. The valve is closed in the center
(Closed) position. The valve remains open when the switch is in the up
(Continuous Open) position until the switch is moved to the center (Closed)
position. The down (Momentary Open) position must be pressed and held to open
the valve; when released it automatically returns to the center (Closed) position.
Leave the control switch in the center (Closed) position for automated, remote
control operation of the Flow Valve Module with the 2100AN Turbidimeter. Static
or Dynamic measurement is selectable on the 2100AN Turbidimeter during
automated operation; fill time and measurement time also are programmable.
Carefully add sample to the Inlet Reservoir to minimize entrapment of air bubbles
in the sample. Air bubbles create a false positive interference in turbidity
measurement. Always slowly pour sample down the inside edge of the reservoir.
5.2.2.3 Selecting
Static
or
Dynamic
Modes
The 2100AN Turbidimeter is programmable for making static (discrete sample
volume) or dynamic (continuous flow) sample measurements during automatic
operation. The flow valve opens for a programmed fill time when the Static mode
is selected; the Flow Cell fills and purges the previous sample. The flow valve
closes when the specified time period ends, trapping the last portion of sample
flowing through the cell so that a discrete, non-flowing (static) sample volume is
measured. When the measurement cycle is complete, the final reading in the
instrument's display is held and automatically transmitted to the built-in printer
(and/or through the RS232 output to an external printer or computer if connected).