Components; Mode Of Operation Of The System - Grundfos Oxiperm OCD-164 Montage- Und Betriebsanleitung

4.2 Components

4.2.1 Suction lines
The suction lines must be matched to the tank size and the
system performance (diameter of suction line). They have a dual
level-control unit.
If the level of the components (HCl/NaClO
stage ("Min" contact/pre-empty signal), the alarm "HCl- MIN" or
"NaClO MIN" is output. This is indicated by flashing of a LED on
2
the controller display. The system remains in operation, the relay
"pre-empty signal NaClO /HCl" is activated.
2
The system is switched off when the second stage is reached
("Min"-"Min"contact/empty signal), and the alarm "HCl empty
signal" or "NaClO empty signal" is displayed, the "Alarm" is
2
activated and the alarm LED lights up red permanently.
If a buzzer is connected to the potential-free output relay, an
audible signal is output.
4.2.2 Dosing pumps
The dosing pumps are mounted at the supporting frame. They
operate according to the pulse/pause procedure. The stroke
length is adjusted with a rotary knob. The stroke length is preset,
but may have to be corrected following gauging of the pumps
since the local pressure conditions depend on the application.
The dosing pumps for the systems OCD-164-30 to OCD-164-220
are delivered with an integral gauging system. Gauging of the
dosing pumps for the systems OCD-164-350 to OCD-164-2000 is
carried out using calibration cylinders on the suction side.
Refer to the table 2.1.1 Performance and consumption data
the dosing rate to be set for the pumps.
The dosing rates of the pumps should be set approximately the
same (± 10-15 %) to guarantee uniform consumption of the
chemicals.
The stroke length must not be adjusted any further following
gauging.
4.2.3 Dosing controller
The dosing controllers guarantee that both chemicals flow into
the system during operation. If the volume flow of one of the
chemicals drops by more than 25-30 %, the dosing controller
outputs an alarm and switches off the system.
The working point must be correctly set to guarantee safe
functioning of the dosing controller, see section
A correctly set working point is indicated by the flashing LEDs on
the controller flowchart, see section
elements.
4.2.4 Reactor
The reactor is installed at the rear of the supporting frame. The
non-return valves on the reactor inlet and outlet must be selected
depending on the system pressure. Standard valves are suitable
for a system pressure of less than 3 bar.
4.2.5 Bypass
The bypass water line dilutes the chlorine dioxide solution
generated in the reactor (approx. 20 g/l) and routes it to the main
water flow. Several versions of the bypass line are available:
• Bypass with solenoid valve and flow limiter
• Bypass with circulation pump
• Bypass with solenoid valve and dosing ball valve (batch mode)
• Bypass for external booster pump (and load unit), see section
10.9 Bypass for external booster
The water in the bypass is monitored by a flowmeter. The
flowmeter switches the system off, if the bypass water falls below
a minimum flow; the LED on the flowchart flashes. The LED lights
up permanently, if the water flow is above the minimum quantity,
see section 6.2 Control and display
Fit a particle filter upstream, if the bypass water is not
Note
free of solids.
12
) drops to the first
2
for
7. Commissioning.
6.2 Control and display
pump.
elements.
4.2.6 Post-mixer
The chlorine dioxide solution is mixed with the bypass water in
the post-mixer (standard).
4.2.7 Options
Power Supply
• 230 V, 50/60 Hz
• 115 V, 50/60 Hz.
Bypass
• Bypass with pump 230 V, 50/60 Hz
• Bypass with pump 115 V, 60 Hz
• Bypass with solenoid valve 230 V, 50/60 Hz and flow limiter
(standard)
• Bypass with solenoid valve 115 V, 50/60 Hz and flow limiter
• Bypass for external booster pump, see section
external booster pump.
Suction lines
• Suction line 1.3 m for 30/60-litre tank (standard)
• Suction line 2.5 m for 30/60-litre tank
• Suction line 2.5 m for 200-litre tank.
Exhaust device
• Exhaust device, DN 20, 230 V 50/60 Hz (standard)
• Exhaust device, DN 20, 115 V 50/60 Hz
• Without exhaust device.
Reactor non-return valves
• System pressure less than 3 bar (standard)
• System pressure more than 3 bar.
Bus systems
• Profibus DP module
• Ethernet TCP/IP module.
Interface
• RS-232 interface
• RS-422 and RS-485 interface.

4.3 Mode of operation of the system

Positions in brackets, see fig. 4.
When the system is started in normal mode, the solenoid valve
(3.1) opens. Dilution water flows to the post-mixer (5), the flow is
controlled via the impeller counter (3.2).
The two dosing pumps simultaneously pass 9 % hydrochloric acid
and 7.5 % sodium chlorite solution with a ratio of 1:1 into the
reactor (4). The flow quantities of the chemicals are monitored by
the dosing controllers (1.3 and 2.3).
The reaction between sodium chlorite and hydrochloric acid results
in a chlorine dioxide solution with a concentration of 20 g/l in the
reactor (4). The dwell time in the reactor is approx. 10 minutes.
In the subsequent mixer, this solution is diluted down to a
concentration of max. 3.3 g ClO
and performance setting, and passed on to the injection unit.
The system is switched off immediately, if one of the dosing
controllers or the impeller counters detects a low flow.
Warning
Chlorine dioxide is a toxic gas, hydrochloric acid and
sodium chlorite are highly corrosive chemicals which
must be handled properly.
Installation and operating personnel must therefore
be acquainted with the regulations concerning the
handling of chlorine dioxide, hydrochloric acid and
sodium chlorite.
In Germany, the accident prevention regulations UVV
are applicable.
10.9 Bypass for
/l, depending on the system size
2