REFEX pH System for all stages of Potable / Waste

Water Treatment

For more information:www.southforkinst.cominfo@southforkinst.com

T: 925-461-5059

Page 2

Application/Retrofit Index:

> Food and Beverage – Dairy – non-glass – protein resisting > Sulphides – Sour Waters with H2S – Desulphurization of Flue gases – Stack Gas Scrubber waters. > Ultra Pure Waters – Boiler Feed – Power Generation – Refex being non-porous there’s no diffusion potention error (all other leaking reference electrode in UPW produce a pH 0.3 diffusion potential error across the liquid-junction) > Silicates/Chromates/Cyanide/HF – Refex is resistant to chemical and abrasion attack – only the measuring electrode needs to be replaced. > NaOH and KOH and most acids – Refex is resistant to pH extremes > Pigments and Fine particles (Ti02 and Indigo Blue being typical) > Potable Water Treatment (all stages including cold low ionic raw waters with magnesium and iron traces) > Sewage and Effluent Neutralization – being non-porous – Refex does not foul. > Withstands varying pressures up to 20BAR and vacuum. > Withstands varying temperatures 0.90C > Withstands all Oil/LNG and most petrochemical applications.

Retrofits and Cable/connectors:

Refex Cable and Cap Connector Systems

> IP65 Fixed cable – standard lengths 1,3,5,10m > Euro Cap Connector System with PG13, 5 (S.7 type) > Yokogawa Head Cap System > ABB/Emerson 1” NPT process mounting > ¾” BSP Flow Cell process mounting

REFEX pH Sensors Introduction:

Refex is a solid State Ag/AgCl reference electrode.

Refex is unique being the only non-porous/non-leaking reference electrode

Refex has replaced the need to have a liquid-junction and acts as both an immobilized electrolyte and also a non-porous protective interface separating the medium under test from the internal Ag/AgCl half-cell. The entire outside surface of the Refex electrode is electrochemically active – it does not foul – even when completely coated (oily waste water being a good example) Being non-porous Refex continues to perform up to 20BAR pressure and full vacuum. Refex withstands varying temperature between 0.90 C without degrading (no sucking / blowing of electrolyte). Refex being non porous has a higher impedance than leaking/porous reference electrodes – typically Refex has an impedance< 50Kohm – this is not a problem with modern pH transmitters with duel high impedance galvanic ally separated sensor inputs. Refex is a non-glass reference electrode compatible with all electrochemical-measuring electrodes. Refex can be used for anodic corrosion

potential measurements.

Refex Retrofit electrodes for existing pH installations:

> ABB/TBI > Emerson > Yokogawa > Endress and Hauser

fig. 1Conventional pH electrodePorous Junction

Ag/AgClHalf-cell

Porus Junction

pH Glass

Low Ionic Raw Water

fig. 2REFEX pH electrodeNon-Porous Junction

Ag/AgClHalf-cell

pH Glass

Low Ionic Raw Water

Non-porousREFEX ionic

interface

Sealed internal

Ag/AgClReference

and KClElectrlyte

Page 3

The Refex solid state reference system against the Refex pH glass electrode responds instantaneously to pH change. This is a very important quality when titration and chemical dosing is required. The entire wetted outside surface of the Refex reference electrode is electrochemically active – non-porous - without diffusion potential / flow errors – and also resistant to fouling – the instant response and accuracy of the Refex electrodes prevents pH over-shoot and unnecessary wastage of expensive dosing chemicals resulting in significant savings. ( see Fig 1.)

Slow responding conventional electrodes over-shoot and exceed the high and low pH alarm settings –this roller coaster effect results in unnecessary wastage of dosing chemicals ( See Fig 2.)

Evaluation of a New Solid-State Reference Electrode Junction Material for Ion-Selective Electrodes.By Dermot Diarmond, Eamon McEnroe and Mary McCarrick. School of Chemical Sciences, Glasnevin, Dublin 9, IrelandAndrzej Lewenstam. Laboratory for Analytical Chemistry, Ado Akademi, SF-20500 Turku, Finland

Received September 12, 1993

The performance and properties of a new low-resistance material, Refex, suitable for use in reference electrode junctionsis described. The material is a solid polyvinyl acetate that contains a very large loading KC1 (1:1 w/w KC1/PVA). Despite relatively large active surface areas in the designs studied (stand-alone reference and combination Ph), leakage rates of KCI are remarkably low.

pH measurements in ultrapure water and comparative measurements in common buffer solutions against standard refernce electrodes confirm the stability of the potential developed across the junction to be very stable. Impedance studies verify the importance of the KC1 doping for realisation of the low resistance and

attractive electrochemical properties of the material.

Instant response to pH change.

Shaded Areas = pH Overshoot and Wasted Dosing Chemicals

High pH

Low pH

fig. 2Normal pH Sensor with Porous JunctionpH Response = 'Rollercoaster' Overshoot

fig. 1REFEX Non Porous pH Sensor - Solid StatepH Response = Alpine Peaks = No Wastage of Dosing Chemicals

No Wasted Dosing Chemicals

High pH

Low pH

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REFEX pH System for all stages of Potable Water Treatment

Equipment:

Process pH/REFEX Combination Probe

Type: EC-3/4"BSP-2001-TC-1mTC Options: Pt100

Pt1000 3 KOhm Balco

(Please specify required TC when ordering.)

Verification ElectrodeType: EC-FT-PG 13,5-2001-25mm-Pt1000-BNC

1 x PP. Flow Cell1 x PVC Bypass System

1 x Knick pH 2402 Transmitter

1 x Knick Portamess 911 Hand held pH Meter

1 x IP65 Enclosure

1 x Panel Heater

1 x Back Panel

pH Transmittor

IP65 Enclosure

Panel Heater

pH Sensor

Shut OffValve

Shut OffValve

Shut OffValve

Verification pH Combination

MAINS POWER SUPPLY

4/20 mA

FLO

W I

N

BYPASS FLOWFLO

W O

UT

KNICK Portamess Hand Held pH Meter

Flow rate < 5L/min

7.5

7.5

Page 5

A A

B

B

-

SECTION A-AOPTION 1.

Process Comb. & Verification Comb.

SECTION B-BOPTION 2.

Separate pH Glass & REFEX Solid State Reference

Electrostatic

Ground

pH Glass Electrode< 150MOhm

Temp Comp

75mm Dia

Temp Comp

Wetted Surfaces:

> Polypropylene & Polycarbonate

Flow Cell

> Liquid Earth

> pH Glass Electrode & Ryton Body

> Viton 'O' Rings

> REFEX Reference

Specifications:

pH Range

Temp Range

Reference

Process Fitting

Cable Length

Temp Comp

: 0-13.5 <150 MOhm

: 0-60 DegC

: REFEX Solid State

< 20 kOhm

: 3/4" BSP

: 1, 3, 5, 10m (Please Specify)

: Pt100, Pt1000, 3kOhm

(Please Specify on ordering)

Liquid EarthSolution Ground

Equipment:

Transparent Flowcell:

Process Fittings 1/4" NPT (in/out)

Materials: Polypropylene, Polycarbonate

Electrode Option 1:

Process REFEX/pH Combination Electrode

EC-3/4”BSP-2001-Pt1000/Pt100-1m/3m/5m/10m

Verification REFEX/pH Combination

EC-FT-PG 13,5-2001-Pt1000-BNC

Electrode Option 2:

Single pH Electrode

EC-FT-PG13,5-5610-25mm 1m/3m/5m/10m

Refex Reference

EC-3/4”-BSP-5710-25mm 1m/3m/5m10m

With inbuilt TC (Please Specify on ordering)

Pt1000, Pt100, 3Kohm

3/4" BSP Process Fitting

73mm

FLOW IN

Refex Reference = Green

TC = White

TC = Red

pH = Transparent

pH Screen = Braid

Liquid Earth Bolt

PG 13.5 (F)

3/4" BSP (F)

Refex pH System for Potable Water Treatment

Mounting Bracket

FLOW OUT

3/4" BSP Free Turning

KNICK Portamess Hand Held pH Meter

Verification Electrode

Type EC-FT-PG 13.5-2001-Pt1000-BNC

7.5

Process Electrode

Type EC-FT-PG 13.5-2001-Pt1000-BNC

Refex Reference = Green

TC = White

TC = Red

pH = Transparent

pH Screen = BraidREFEX Reference ElectrodeType EC-FT-3/4"BSP-5710-25mm-TC

Single pH Electrode

EC-FT-PG13,5-5610-25mm

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REFEX pH Bypass System for all

stages of Potable Water TreatmentCompatible with all models of pH

Transmitters

Equipment:

Process pH/REFEX Combination Probe

Type: EC-3/4"BSP-2001-TC-1m

TC Options: Pt100 Pt1000

3 KOhm Balco(Please specify required TC when ordering.)

Verification ElectrodeType: EC-FT-PG 13,5-2001-25mm-Pt1000-BNC

1 x PP. Flow Cell

1 x PVC Bypass System

1 x Back Panel

pH Sensor

Shut OffValve

Shut Off

Valve

Shut OffValve

Verification pH Combination

FLO

W I

N

BYPASS FLOW

FLO

W O

UT

Flow rate < 5L/min

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25mm

75mm

Refex pH System for Potable Water Treatment - Electrode Option 1.

Free Turn 3/4" BSP

Black JumboREFEX Reference (16mm Diameter)(20 KOhm)

Temperature CompensatorPt100, Pt1000, 3kOhm

Wrench Flat

pH Glass Electrode(<150 MOhm)

REFEX/pH Combi Electrode (Verification):

pH Range

Temp Range

Process Fitting

Cable Options

Temp Comp

Part No.

pH Meter

: 0-13.5

: 0-60 DegC

: PG 13.5

:1m/3m/5m/10m

: (Please Specify)

: Pt1000

: EC-FT-PG13.5-2001-25mm-Pt1000-11-BNC

: Knick Portamess 911

Temp Comp = White

Temp Comp = RedRefex Reference = Green

REFEX/pH Combination Electrode (Process):

pH Range

Temp Range

Reference

Process Fitting

Cable Options

T.C. Options

Wetted Surfaces

Part No.

: 0 - 13.5 (100mOhm)

: 0-60 DegC

: REFEX Solid State <20kOhm

: 3/4" BSP Free Turning

: 1m/3m/5m/10m (Please Specify)

: Pt100, Pt1000, 3kOhm (Please Specify)

: Refex Reference,

: Ryton Body, Viton 'O' Ring

: EC-FT-3/4"BSP-2001-TC-Cable

25mm

PG 13.5 Free Turn Cap

Viton 'O' Ring Seal

12mm Diameter

pH Glass Impedence <150 MOhm

IP66/NEMA 4

IP66

pH Screen = Braiding

pH Glass Electrode = Transparent

Page 8

25mm

75mm

Refex pH System for Potable Water Treatment - Electrode Option 2.

Free Turn 3/4" BSP

Black JumboREFEX Reference(20 KOhm)

Temperature CompensatorPt100, Pt1000, 3kOhm

Wrench Flat

16mm Diameter

pH Glass Electrode:

pH Range

Temp Range

Process Fitting

Cable Options

Part No.

: 0-13.5

: 0-90 DegC

: PG 13.5

:1m/3m/5m/10m

: (Please Specify)

:EC-FT-PG13.5-5610-25mm

Temp Comp = White

Temp Comp = Red

pH = Transparent

pH Screen = Braid

Refex Reference = Green

REFEX Reference Electrode:

Temp Range

Impedence

Process Fitting

Cable Options

T.C. Options

Wetted Surfaces

Part No.

: 0-90 DegC

: 20 kOhms

: 3/4" BSP

: 1m/3m/5m/10m (Please Specify)

: Pt100, Pt1000, 3kOhm (Please Specify)

: Refex Reference,

: Ryton Body, Viton 'O' Ring

: EC-FT-3/4"BSP-5710-25mm

25mm

PG 13.5 Free Turn Cap

Viton 'O' Ring Seal

12mm Diameter

pH Glass Impedence <50 MOhm

IP66

IP66

Page 9

KNICK Portamess 911 pH Meter

KNICK Portamess 911:

> The Portamess 911 (X) pH is used for pH and temperature

measurement in industry, environment, food processing and waste

water treatment.

> The unit meets the European EMC regulations (89-336-EEC) and the

recommendations of NAMUR NE 21.

> The unit IP 66 protected to EN 60529 (jet water from all directions)

> Temperature Compensation is automatic with a Pt1000 temperature

probe, an NTC 30 kOhm (automatic recognition during power-on)

or through manual temperature input.

> Calibration can be carried out with buffer solutions from various,

preselectable buffer sets. The buffer is then automatically recognised

by the Calimatic.

> You can also calibrate manually by entering individual buffer values.

> The Sensoface electrode monitoring system checks the connected

electrode and provides information on its state.

> Only three alkaline AA batteries are required for uninterrupted

operation for approx. 2,000 hours.

Refex pH System for Potable Water Treatment

Electrode Option 2. - Verification using KNICK 911 Hand-held meter

pH Sensor

Shut OffValve

Shut OffValve

Shut OffValve

Verification pH Combination

FLO

W IN

BYPASS FLOW

FLO

W O

UT

Flow rate < 5L/min

7.5

KNICK Portamess 911Hand-Held pH Meter

Over-flow beakerWater to drain

REFEX pH Combination electrodeType - EC-3/4"-2001-Pt1000-1m-BNC +4mm

Page 10

REFEX IMMERSION/WASHER SYSTEMFor Sewage Treatment Applications

Temp Comp:

PT100PT1000

3K BalcoPlease Specify

Cable Options:

3m5m

10mPlease Specify

Hose Connection

1000mm

Dip System/Immersion System

Moveable Flange

Electrode TypeEC-3/4"-2001-TC

Wash ModuleType PVC-WS

PANEL MOUNTED pH METER PLAN VIEW

Power Supply

Immersion SystemType IMPP

Panel Heater

4 to 20 mA

pH Transmitter

7.5

Page 11

Solution: When new Refex pH sensors are installed into the flow cell - it is advisable to allow the sensors to become conditioned for 2 hours in the flow - before the final pH calibration is made. The electrodes are stored in 3.0mol/l KCl and it will take 2 hours for the sensors to become conditioned to the flowing raw and treated water. The Refex electrode is guaranteed for 12 months in operation - and should be replaced annually as a preventive maintenance protocol.

Conclusion:The Refex pH system provides a technically unrivalled and consistent pH performance - guaranteed for 12 months with the minimum amount of maintenance - no wasted dosing chemicals. High-resolution automatic measurement and dosing control. The most important stages being Raw and treated water waters - the flocculation/coagulations optimized ensuring trouble free treatment at every stage downstream and optimized high yields of top quality compliant final water.

pH Verification between the various stages of Potable Water and Lab.

Problem: To obtain pH verification it is necessary to follow certain protocols. Taking grab samples back to a remote laboratory for pH measurement always results in confusion and pH differences compared to the process pH values. The reasons for this is that the grab sample is exposed and contaminated by air - the sample is static as opposed to flowing with different measuring conditions, pH sensors, pH meters, pH buffers and temperatures.

In order to obtain reliable and accurate pH verification - The verification measurement should be made at the process point in a flowing condition (an overflowing beaker or directly in the pH sensor flow cell beside the process pH sensor) A level playing field must be established - the process and hand held pH instruments should be calibrated at the process point at the same time using the same buffers and also the same electrode type and at the same temperature. PH buffers 4.01 and pH 6.88 should be used - a two-point calibration is sufficient. Working to this protocol pH verification and agreement is assured. Taking grab samples back to a remote laboratory only produces pH anomalies and is never advised.

fig. 1

pH Verification on-site using REFEXSolid-state pH combination electrode-same as process.

fig. 2

pH Verification in the Lab.

Page 12

Solution: Should the pH response start to become sluggish due to pH glass electrode coating, the pH Glass electrode is easily cleaned using detergent, mild HCl acid or caustic wash. Sometimes during the cleaning of the pH electrode (wet wad of cotton wool) the electrode can become statically charged - after cleaning the pH glass membrane the electrode should be given 15 minutes to become discharged and reconditioned to the environment of the medium under pH test before recalibration of the electrodes (2 point calibration is sufficient).

The REFEX reference electrode is a non-porous solid-state reference electrode unaffected by coating build up and being non-porous cannot clog. When the coating build up on the outside surface of the REFEX electrode remains wet and conductive the mV output from the REFEX electrode remains the stable. The outside surfaces can be cleaned off using the same cleaning method as the pH glass electrode. The electrodes pH and REFEX must be kept hydrated at all times - dehydrations of the electrodes increases the impedance of the REFEX (out of range).

Conclusion: The REFEX solid-state electrode has overcome the main problems relating to reference electrode coating and contamination. The non-porous quality has overcome the precipitations problems (sulphides and proteins etc.). The performance is almost maintenance free and the life of the electrodes extended by many times the normal. REFEX continues to perform even in the most highly contaminated sewage, process and industrial effluent waters.

(See Fig 3.)

Effects of fouling and deposit coating of pH and Reference electrodes

Problem: Electrode fouling has to date been one of the major problems requiring frequent electrode cleaning and recalibration. The problems relate to the need for a porous liquid-junction for the reference electrode. The porous junction can be porous ceramic, Teflon, even wood. The liquid junction becomes clogged by the medium this increases the impedance. Typical coating problems are lime scaling, manganese, precipitation between hydrogen sulphides with AgCl, Proteins/fat build up in sewage and industrial effluents. Fine particle clogging –pigments and dye stuffs etc. Reference electrodes are low impedance sensors (typically 5 kOhm) the pH glass electrode is a high impedance sensor (typically 100 MOhm) clogging/coating deposit on sensors increases the impedance by 1Mohm – this is not a major problem for the pH glass electrode – the impedance increases to 101 MOhm (1% increase) however the impedance across the porous liquid junction increases from 5 kOhm to 1005 kOhm – this is exactly where the problem lies. One solution has been the pressurization of the electrolyte to force a positive KCl out-flows across the junction to prevent clogging of the liquid

junction – this method is expensive and still did not over-come precipitation clogging. (See Fig 1 and Fig 2.)

fig. 1

CLEAN POROUS JUNCTION

pH Glass

Electrode

KCl Electrolyte

Ag/AgCl

Half-cell

Porous Liquid

Junction - CLEAN

100 MOhm 5 kOhm

fig. 2

CONTAMINATED POROUS JUNCTION

pH Glass

Electrode

KCl Electrolyte

Ag/AgCl

Half-cell

Porous Liquid

Junction - CLOGGED!

(The Black Death)

(1 MOhm Increase)101 MOhm 1005 kOhm

fig. 3

CONTAMINATED REFEX NON-POROUS JUNCTION

pH Glass

Electrode

KCl Electrolyte

Ag/AgCl

Half-cell

NON POROUS

REFEX - SOLID STATE

(Entire outside surface active)101 MOhm 50 kOhm

For more information:www.southforkinst.cominfo@southforkinst.com

T: 925-461-5059