© abb group september 1, 2014 | slide 1 4690 turbidity systems accurate, reliable turbidity...
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© ABB Group April 11, 2023 | Slide 1
4690 Turbidity SystemsAccurate, reliable turbidity measurement
© ABB Group April 11, 2023 | Slide 2
ABB’s Range of Turbidity Sensing SystemsIn-line flow-through and in-situ dip sensors
4690 Range A range of flow-through turbidity
systems available with optional auto-cleaning for reduced maintenance
EPA180.1 & ISO 7027 compliant designs based on light scatter
Ranges available to measure up to 400 NTU
4670 Range A range of flow-through and in-situ dip
sensors with auto-cleaning for reduced maintenance
Measures light absorption to calculate turbidity value
Ranges available to measure up to 2000 FTU
All systems available with dry secondary calibration standards for reduced cost of ownership
© ABB Group April 11, 2023 | Slide 3
4690 Turbidity Range For the measurement of turbidity in drinking water
Turbidity is a critical measurement in drinking water -indicates water quality and filtration effectiveness
ABB’s 4690 range of turbidity systems offer reliable, accurate turbidity measurement with low cost of ownership
Suitable for turbidity measurement throughout the drinking water plant
© ABB Group April 11, 2023 | Slide 4
Accurate, Reliable Turbidity Measurement Throughout the drinking water plant
1. Raw Water/Source Monitoring
Provides an indication of the solids loading entering the treatment plant to enable adjustment of the coagulant dose.
2. Monitoring clarified water
Clarifier supernatant turbidity measurement monitors clarifier efficiency to provide early warning of floc blanket break-up or incorrect coagulant dosing.
3. Filter backwashing control
Monitors filter backwash curve to minimize clean water usage.
4. Monitoring of filtered water
Ensures correct operation of the filters and guards against turbidity breakthrough.
5. Monitoring of final drinking water quality
Provides a final quality check after disinfection before distribution.
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© ABB Group April 11, 2023 | Slide 5
Principle of OperationNephelometric measurement
The 4690 range of turbidity sensors utilize a nephelometric design
Light passes through the sample where it is scattered by any suspended particles
such as silt, clay, algae, organic matter, microorganisms, colloidal material, and large dissolved molecules
This scattered light is measured by a detector that is located at a 90° angle to the incident beam
Detector response correlates to turbidity
A higher level of scattered light reaching the detector results in a higher turbidity value
Ultralow back-scatter allows for very accurate readings as only light scattering due to turbidity is measured
Light is scattered by suspended particles in the water
Ligh
tLight
Source
Lens
Lens
Detector
Scattered light is measured at a 90° angle to the incident beam
© ABB Group April 11, 2023 | Slide 6
Choice of Both ISO and EPA Compliant SensorsSuitable for regulatory monitoring
EPA1 Compliant Sensor
EPA 180.1 compliant sensor uses a “White Light”
White light sensor is good for low level turbidity measurement
Suitable for US EPA reporting of filtered water
ISO2 Compliant Sensor
ISO 7027 compliant sensor uses a “Near Infrared LED”
The wavelength (860-890nm) is less susceptible to color interferences
Good for both low level turbidity measurement and for measuring samples with color
1 United States Environmental Protection Agency
2 International Organization for Standardization
© ABB Group April 11, 2023 | Slide 7
4690 Turbidity Systems Product overview
Wall- or panel-mounted transmitters available
Easy-to-use, ultra-stable electronics with in-built digital filters for bubble rejection
Auto-clean system
Programmable automatic cleaning reduces maintenance and ensures sensor accuracy and reliability
Dry Standard Standards
Simplifies routine instrument verification, eliminates chemical standard preparation errors and reduces cost of ownership
Sample Flow Cell
Flow-through nephelometric design with minimal sample residence time provides fast response to turbidity changes for improved process control
Integral Sample Feed & Drain Valves
Provides simple installation and quick and easy calibration
Emitter & Receiver Assemblies
EPA180.1 or ISO 7027 Compliant design
© ABB Group April 11, 2023 | Slide 8
Flow-Through Sensor DesignFast response and reduced maintenance
Fast Response Time
Minimal sample residence time allows fast response time to process changes
Typically 90% step change in <45 seconds
Up to 75% faster response time than some competitor turbidity designs
Offers improved process control
Reduced Maintenance
Flow-through design does not act as a “sediment trap”
Removes requirement for manual cleaning of settled particles in the sensor body
Reduces cost of ownership
© ABB Group April 11, 2023 | Slide 9
Automatic Cleaning of Optical CellReduces maintenance and ensures accuracy
Optical cell fouling greatly reduces accuracy of turbidity measurement
ABB’s 4690 Sensors feature an Auto-clean system that overcomes the problem of optical cell fouling
Mechanical wiper assembly physically wipes clean the optical cell at user-programmable intervals
No need to regularly disassemble the sensor to inspect/manually clean the photocell window
Reduces maintenance and lowers cost of ownership whilst ensuring accuracy and reliability
© ABB Group April 11, 2023 | Slide 10
Dry Secondary Calibration StandardSimplifies routine instrument verification
Optomechanical filter that diverts a fixed quantity of light to the detector corresponding to a known turbidity value
Each secondary standard is factory calibrated and certified against a primary formazine standard
Quick & simple verification/calibration procedure that minimizes instrument downtime
Reduces cost of ownership by reducing chemical standards and the time taken on-site to prepare such standards
Minimise employee’s exposure to Formazine which is highly toxic and a suspected carcinogen
Simple to use, repeatable and reliable
Insert directly into sensor body during calibration procedure
Available in different turbidity concentrations to suit the application
© ABB Group April 11, 2023 | Slide 11
Patented User Replacement Bulb DesignAllows lamp replacement in under a minute
Changing incandescent bulbs to ensure peak performance used to be a laborious process
With ABB’s replacement bulb design you can throw those cotton gloves away!
Each bulb is supplied fully protected in a patented assembly with integral light guide
No direct contact with the bulb
Ensures maximum lamp life
No threading of wiring
No waiting for the bulb to cool
Simply plug and play
© ABB Group April 11, 2023 | Slide 12
Low MaintenanceMinimises cost of ownership
Task Recommended frequency
Visual check - check sample flow, check for any leaks Weekly
Calibration verification1 with secondary standard2 Monthly
Calibration2 with primary standard4 – as per regulatory guidelines
Quarterly*
Wiper blade replacement Quarterly
“White Light” source (EPA 180.1) replacement Annually
“Infrared” LED source (ISO 7027) replacement Every 5 years
1Calibration verification means a procedure used to check whether or not the calibration of the instrument is within certain limits2Secondary standard means a standard that the manufacturer has certified will give instrument calibration results equivalent to the results obtained when the instrument is calibrated with primary standard such as formazin3Calibration means a procedure which checks or adjusts an instruments accuracy by comparison with a defined standard or reference4Primary standard means a standard, such as formazin, used to calibrate the instrument response with respect to analyte concentration
*Based on EPA guidelines for individual filter effluent
All service tasks can be quickly and easily performed on site without the need for a skilled technician
© ABB Group April 11, 2023 | Slide 13
4690 Turbidity Systems Accurate, reliable turbidity measurement
Flow-through turbidity design Fast response to process turbidity
changes due to minimal sample residence time
Choice of EPA or ISO compliant methods
Automatic sensor cleaning Reduces maintenance requirements Optimises performance sensitivity
Dry secondary calibration standard Accurate, repeatable, simple, safe Realise significant cost savings by
reducing the use of primary standards
Simple to use and maintain Intuitive, user-friendly design Simple-to-perform annual service
Reliable and accurate measurement Ultralow back scatter for accurate
measurement of low turbidity values Automatic bubble rejection to
compensate for erroneous readings due to degassing
© ABB Group April 11, 2023 | Slide 14