Continuous measurement
The Redox electrode continuously analyses the water in the storage tank or in the pipe.
Measurement and control
LDsRh
The Redox potential (ORP), expressed in mV, indicates the disinfecting power of water: it increases in the presence of oxidants such as chlorine and decreases as contamination increases. The LDsRh system measures it and doses hypochlorite or another disinfectant in proportion to the measured value, up to the set point.
- Range −1,000 / +1,000 mV
- High-linearity electrode for drinking water
- In by-pass, in-line or immersion
- Proportional, ON/OFF, PWM, PID
± 1,000mVMeasuring range
1mVResolution
20minMinimum contact time
3Electrode positions
How it works
Disinfection control by means of Redox
The Redox potential to be maintained is set (set point, for example 450 mV) and the system doses the quantity of disinfectant required to reach it.
Insight: well water →
Proportional dosing
The controller drives one or more dosing pumps that inject hypochlorite into the tank, in proportion to the measured potential, up to the set point.
Continuous disinfection
The incoming water, potentially contaminated by pathogenic organisms, immediately comes into contact with the free chlorine and is disinfected, while the pump restores the set potential.
The action of chlorine requires a contact time appropriate to the organisms present, and in any case not less than 20 minutes. By adding a pulse-output water meter and a dosing pump connected to it, dosing also becomes proportional to the volume of water treated; the controller can also drive solenoid valves or other equipment according to the Redox value.
Applications
Applications
Drinking water
Raw water from wells and springs, private and from public water supply networks.
Insight: well water →Domestic water circuits
Domestic water circuits.
Industry
Industrial process water.
Wastewater
Municipal and industrial wastewater.
Components
System components
The system is supplied pre-assembled on a panel. As an alternative to the wall-mounted controller, panel-mount controllers for installation in an electrical cabinet are available.
Controller
It acquires the mV measured by the electrode and activates the dosing pump until the set point is reached.
Redox electrode
Also available in a high-sensitivity, high-linearity version, designed to detect the very low free chlorine concentrations typical of drinking water.
Redox electrodes →
Dosing pump
Solenoid diaphragm pump with wetted parts in PVDF or PP according to the chemical dosed, with flow rate and back-pressure defined at the time of order (VMS or KMS series, up to 18 l/h and 20 bar). For larger volumes, stepper motor or motor-driven pumps are used, up to 1,000 l/h or up to 100 bar; additional pumps can dose film-forming inhibitors.
The pumps →
Redox
Factors affecting the Redox potential
Chlorine, bromine, hydrogen peroxide, peracetic acid and ozone oxidise organic contaminants, such as bacteria and algae. The Redox potential is positive in the presence of oxidants (chlorine) and negative in the presence of reducing substances (sodium bisulphite).
Insight: the Redox potential →pH
The Redox potential depends directly on pH and, to a lesser extent, on temperature: as the pH increases, the effectiveness of the oxidant decreases and a larger quantity of disinfectant is required to reach the same potential. In certain circumstances pH control may also be necessary.
pH control →Pollutant load
With few oxidisable impurities (micro-organisms, organic matter, iron, copper, manganese), a small quantity of disinfectant is sufficient to obtain a high potential. As the pollutant load increases, the potential decreases and the system increases dosing to restore it.
Direct measurement in mg/l
The Redox measurement does not compensate for pH variations or for the effect of chemicals that may alter it. For the direct measurement of free chlorine in mg/l, with automatic pH compensation, the LDsCL amperometric system is used.
LDsCL system →
Technical data
Probe data sheet
The controller measures the Redox potential from −1,000 to +1,000 mV (resolution 1 mV) and the temperature from 0 to 100 °C (resolution 0.1 °C); electrode self-cleaning on request; electrode in by-pass, in-line or immersion.
Redox electrodes
| Electrode | Range | Pressure | Connection | Body | Minimum conductivity | Junction | Temperature | Cable | Diameter | Notes |
|---|---|---|---|---|---|---|---|---|---|---|
| ERhS | ± 1,000 mV | 7 bar (3.5 bar) | BNC | Epoxy | 100 µS | – | 70 °C (80 °C) | 0.8 m | 12 mm | – |
| ERhM | ± 1,000 mV | 7 bar (3.5 bar) | BNC | Epoxy | 100 µS | – | 70 °C (80 °C) | 4.5 m | 12 mm | – |
| ERhL | ± 1,000 mV | 7 bar (3.5 bar) | BNC | Epoxy | 100 µS | – | 70 °C (80 °C) | 15 m | 12 mm | – |
| ERhHLB SN6 | ± 1,500 mV | 6 bar | SN6 with PG13.5 thread | Glass | 100 µS | – | 80 °C | 10 m | 12 mm | High linearity and sensitivity, for low chlorine concentrations |
| ERhSN6 | ± 1,000 mV | 7 bar | SN6 with PG13.5 thread | Epoxy | 100 µS | – | 100 °C | 1 – 100 m | 12 mm | – |
| ERhMD/100 | ± 1,000 mV | 7 bar | BNC | Epoxy | 100 µS | Double | 100 °C | 4.5 m | 12 mm | – |
| ERhM/D | ± 1,000 mV | 7 bar (3.5 bar) | BNC | Epoxy | 100 µS | Double | 70 °C (80 °C) | 4.5 m | 12 mm | – |
| ERhSC | ± 1,000 mV | 7 bar (3.5 bar) | BNC | Epoxy | 100 µS | Double | 70 °C (80 °C) | 4.5 m | 12 mm | Self-cleaning |
| ERhSC/SN6 | ± 1,000 mV | 7 bar (3.5 bar) | SN6 with PG13.5 thread | Epoxy | 100 µS | Double | 70 °C (80 °C) | 1 – 100 m | 12 mm | Self-cleaning |
All models: combination electrode, resolution 1 mV.
Installation
Electrode positioning
Electrode positioning is defined according to the characteristics of the installation and of the water to be analysed.
In by-pass
The probes are housed in a PEF flow-through probe holder or an NPED probe holder, connected to a water tapping point at the tank outlet and fed with about 30 l/h of sample water. A flow sensor can be added, which stops dosing when there is no flow.
Probe holders →
Immersion
The electrode is immersed directly in the storage tank of the water to be treated, by means of an immersion probe holder.
Probe holders →
Immersion with cleaning
A solution suited to heavily loaded water: at programmed intervals the control panel puts the controller in stand-by and opens a solenoid valve that sends water or air to the nozzle; once cleaning is complete, it closes the valve and, after the electrode repolarisation time has elapsed, resumes dosing.
Probe holders →
In-line
The electrodes are inserted directly into the pipe carrying the water to be treated.
Probe holders →
Controller
The controller
It acquires the measurement from the probe and drives the dosing pump in proportion to the value detected. It is supplied pre-assembled on a panel, ready for connection.
Colour display
Multicolour backlit display that indicates the different operating states by changing colour. Programming via a single knob.
Four modes
Proportional, ON/OFF, PWM and PID dosing, with delayed dosing start.
Data storage
Permanent data storage and a system log viewable on the display; the internal log can be exported to a USB memory stick for processing with a spreadsheet.
Alarms
Chemical level, no flow, maximum dosing time exceeded, probe failure, out-of-range reading; acoustic or visual signalling via the alarm output.
The dosing pump, with flow rate and back-pressure defined at the time of ordering, is connected to the pulse output (and/or 0-4/20 mA) and operates in proportional or ON/OFF mode. A pre-calibrated injection valve and a magnetic level probe with coaxial foot filter, which stops the pump when the chemical runs out, are supplied as standard.
Colour display
Colour-coded status indication
By changing colour, the controller’s backlit display indicates the different operating states, which can be recognised even from a distance.
Normal operation
Measurement and dosing according to the set parameters.
Stand-by
Controller in stand-by.
Warning
Warning signal, for example the chemical level.
Alarm
Alarm signal, for example from the probe.
Settings from the display
Data sheet
Controller data sheet
Inputs, outputs, control modes and alarms of the controller.
Inputs
- Measuring probe
- Temperature
- Flow sensor
- Chemical level
- Pulse-output water meter or mA signal
Outputs
- 1 proportional dosing pump
- 1 digital output
- 2 proportional 0-4/20 mA outputs
Control
- Proportional
- ON/OFF
- PWM
- PID
- Delayed start
Alarms
- Chemical level
- No flow
- Maximum dosing time
- Probe failure
- Out-of-range reading
Power supply
- 230 VAC
- 12 – 24 VDC
Remote control
System remote control
The controllers can be remotely controlled bidirectionally (read and write) from the web portal, from PC, tablet and smartphone: viewing of measurements, modification of set points, dosing and alarms, receipt of alarms and download of logs. Alternatively, integration into your PLC via Modbus is possible.
Ethernet Optional, one of these
Connection to the web portal via network cable: measurements, set points, dosing and alarms accessible from PC, tablet and smartphone.
Wi-Fi Optional, one of these
Wireless connection to the web portal, with the same functions as the cable connection.
4G Optional, one of these
Connection via the cellular network for installations without a local network, with alarm notification by SMS or e-mail.
Modbus RTU Standard (standard models), optional (PLUS)
Integration into your PLC via serial port.
0-4/20 mA output Standard (PLUS), optional (standard models)
Current signal proportional to the measured value, for remote monitoring or for controlling pumps and other instrumentation.
One communication type at a time: Ethernet, Wi-Fi, 4G or Modbus RTU (built into the standard versions, optional on the PLUS versions). 4/20 mA outputs and meter input standard on the PLUS versions, optional on the standard versions.
The NIMBUS portal
A single account brings together all registered installations, each with its own devices: the web portal, free of charge and with no subscription, can be accessed from PC, Mac, tablet and smartphone and allows every parameter to be both viewed and changed, with an encrypted connection and protected access.
Overview
On a single screen: probe readings, chemical levels, pump activation thresholds and active alarms, with the status of installations and devices (normal, warning, alarm, standby, not connected).
Installation map
Installations appear on an interactive map with their status and open with a click; for each one, the local weather conditions and temperature are also shown.
History and charts
Archive of measurements and alarms, available for consultation at any time with charts and numerical reports exportable in Excel format.
Alarms and notifications
Alarm thresholds for readings, dosing, faulty probe and out-of-range readings, with notification by e-mail or SMS depending on the communication system; a warning is also issued when an installation remains disconnected beyond the set time.
Set points and dosing
Remote modification of the set points, of the dosing pump activation thresholds and of the corresponding hourly flow rate.
Inputs and outputs
Status of relays, pulse outputs, digital inputs and current outputs, with the name assigned to each connection.
Maintenance calendar
Tasks are scheduled by installation or by device and assigned to technicians; a reminder is sent by e-mail two days before the due date. Each task is shown as scheduled, due, overdue or completed.
Team and permissions
The main account has full access and creates the technicians’ accounts, each enabled only for the assigned installations and devices; the last login and activity of each technician are visible.
Reports and activity log
Reports on devices, tasks and technicians, downloadable in PDF or CSV with the customer’s logo; the log keeps the history of operations and disconnections.
Customisation
Logo, main colour and light or dark theme; the tiles on the main screen can be rearranged by dragging them. Two installations can be displayed side by side for comparison.
Guided registration
Each device is added through a guided procedure: the model is recognised automatically and associated with the installation, together with the technician to be contacted.
PLC integration
As an alternative to the portal, the Modbus RTU or TCP/IP port allows integration into the plant supervision system.
Optional extras
Optional accessories
Accessories available on request to adapt the system to the requirements of the installation.
Tank
PE tanks for the chemical, with safety bund.
Details →
Pulse-output water meter
Enables dosing proportional to the volume of water actually treated.
Details →
Flow sensor
Installed on the pump delivery line, it verifies that dosing actually takes place.
Details →
Static mixer
Ensures the chemical is mixed with the water and protects the pipe from direct contact.
Details →
Pulsation dampener
Attenuates the pulsations generated by the dosing pump.
Details →
Injection lance
Injects the chemical into the centre of the pipe.
Details →
Multifunction valve
Pressure, safety and anti-siphon functions combined in a single valve.
Details →
Solenoid valve
Operated by the controller according to the measured value.
Which one to choose
From the simplest to the most complete solution
For chlorine and other disinfectants the basic solution is the dosing station; to dose according to the concentration actually present in the water, measuring controllers are used.
Dosing station
The simplest solution: the pump doses at a constant rate or in proportion to the volume of water measured by the pulse-output water meter.
Details → LDsRh
Dosing based on the Redox potential of the water: an economical solution, based on an indirect measurement.
LDsCL
The amperometric cell directly measures the disinfectant concentration in mg/l, ensuring maximum dosing accuracy.
Details →
LD Dual Parameter
Simultaneous management of two parameters, for example pH and chlorine, with a single controller.
Details →
Centurio PRO
Management of up to 10 parameters and of all the pumps in the installation, with touch screen and remote control as standard.
Details →Technical consultancy
Tell us the type of water to be treated and the disinfectant used: we will propose the most suitable electrode, probe holder, pump and accessories.