Georg Fischer 2764-2767 Operating Manual

Signet 2764-2767 Differential DryLoc® pH/ORP Electrodes

4

Features

• Differential design
for stable measure­ments in the most
aggressive applica­tions

• Long service life even
in severe or difficult
chemical applications

Description

The Signet 2764-2767 Differential pH & ORP
electrodes are built with the DryLoc

®

a Ryton

body, and PTFE reference junction to
handle even the most extreme and harshest of
chemical applications.

These differential electrodes use the field­proven 3-electrode differential technique: the pH
and reference electrodes are measured against
a ground electrode, insuring a steady and stable
signal. The key feature of the differential design
is the reference electrode. The reference ele­ment is housed in a glass half-cell embedded
in the reference chamber and is protected from
compounds that may contain sulfides (H
metals, including lead, mercury, and silver. To
ensure a long service life, the reference features
a refillable electrolyte chamber and a replace­able equitransferant salt bridge, both easily
serviced in the field. The patented porous PTFE
reference junction resists fouling, clogging and
chemical attack.

®

connector,

S) and

2

System Overview

In-Line Installation

Panel Mount

Signet Instrument
(sold separately)

5700 8750 8900

Signet 2750 or
Signet 2760
(sold separately)

Signet 2764-2767
Differential pH/ORP Electrodes

4 to 20 mA Input

Chart Recorder

Signet 2750
(sold separately)

OR

Programable

Controller

PLC

Pipe, Tank or Wall Mount

Signet Instrument
(sold separately)

Logic

Signet
Universal
Adapter Kit
(3-8050)
(sold separately)

Signet 2760
(sold separately)

8750

The other elements of the design are the
solution ground, the pH/ORP electrodes,
and the temperature element. The solution
ground eliminates noisy measurements by
draining electrical current away from the
reference electrode. The pH/ORP electrodes
are designed with a flat or bulb measure­ment surface, and a temperature device that
is positioned at the tip of the measurement
surface, making the temperature response of
T

less than 1 minute. Various temperature

95%

devices offered include 3KΩ, 300Ω, or PT-1000
RTD. The electrodes are used with the Signet
2750 Sensor Electronics, which provides a
blind 4 to 20 mA output or using the digital

3

(S

L) output may be used to connect to the
Signet 8900 instrument. The electrodes can
also be used with the Model 2760 preamplifier
to connect to the Signet 5700, 8750, or other
suppliers’ instruments.

Submersible Installation

Other Instruments

Customer supplied

Flow

Signet 2760
(sold separately)

Panel, Pipe, Tank, Wall Mount

678

RELAY 2

10

RELAY 1

pH

12

2

14

0

ENTER

+GF+

SIGNET

Signet or Other Instrument

5700 8750 8900

Pipe extension
or conduit with
3/4 in. FNPT
threads
(customer supplied)

Signet 2750 or
Signet 2760
(sold separately)

Signet 2764-2767
Differential
pH/ORP Electrodes

• Water-tight DryLoc

®

connector with foul­proof gold contacts

• Porous PTFE refer­ence junction

• Rebuildable refer­ence electrode

• Solution ground

• Temperature sensor
(pH)

• Easy sensor replace­ment using DryLoc®
electrode connector

• Quick temperature
response

• Compatible with all
Signet instruments
and other suppliers’
pH/ORP instruments

Applications

• Water and Waste
Water Treatment

• Coagulation and
Flocculation

• Plant Effluent

• Plating Baths

• Scrubbers

• Textile Dye Process

• Harsh Chemical

Applications

• Heavy metal Removal
and Recovery

• Toxics Destruction

• Surface Finishing

Fittings - Customer supplied

96

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Electrode Key Feaures and Benefits:

• Glass encased reference elec­trode protects the Ag/AgCl (sil­ver/silver chloride) element from
reacting with certain chemical
compounds that typically leach
into the reference chambers.
Keeps the pH/ORP reading
stable.

• Large volume reference elec­trolyte chamber resists dilution
over time for a long service life.
Chamber is refillable.

• Salt Bridge serves as a double
reference junction and is the
first line of defense to keep out
process chemicals from the
reference electrolyte chamber. It
is built with a porous PTFE refer­ence junction which is highly
compatible to chemicals , resists
fouling and build-up of dirt.

• Ryton® body for chemical com­patibility to most harsh chemi­cals. Also able to withstand high
temperatures.

• DryLoc® connector with corro­sion resistant gold pins for quick
and easy sensor removal.

• Capillary TC (temperature sen­sor) embedded in tip of pH/ORP
electrode for quicker tempera­ture response than most other
electrodes on the market.

Electrode Cut-away View

Removable/replaceable
reference salt bridge

Solution ground

Glass enclosed
reference silver
chloride element

Reference Chamber
with electrolyte

Temperature
Element

pH/ORP
electrode

Choosing

Products

Instrument

Multi-Pa-

rameter

Flow

pH/ORP

Conductivity/

Resistivity

Pressure, Level

Temperature,

Model 2764-2767 Electrode Compatibility to Sensors, Preamplifiers, and Instruments

Compatible Signet Instruments

Sensor Temp.

2764-1 3 Kohm 2760-1, -2,

2764-2 PT 1000

2764-3 300 ohm - - - - 2760-1, -2, -11, or -21
2765-1 10 Kohm 2760-1, -2,

2765-2 PT 1000 - - - - 2760-1, -2, -11, or -21
2765-3 300 ohm - - - - 2760-1, -2, -11, or -21
2766-1 3 Kohm 2760-1, -2,

2766-2 PT 1000

Compatible Electrodes

2766-3 300 ohm - - - - 2760-1, -2, -11, or -21
2767-1 10 Kohm 2760-1, -2,

2767-2 PT 1000 - - - - 2760-1, -2, -11, or -21
2767-3 300 ohm - - - - 2760-1, -2, -11, or -21

*Must have internal preamplifier in instrument
**Must use sensor with compatible temperature element; contact technical service for questions

Element**

5700 8750 8900 PLC Other Mfr’s Instruments

-11, or -21

-11, or -21

-11, or -21

-11, or -21

2760-1, -2,

-11, or -21

--

2760-1, -2,

-11, or -21

2760-1, -2,

-11, or -21

--

2760-1, -2,

-11, or -21

--

any 2750 w/
digital output

any 2750 w/
digital output

--

any 2750 w/
digital output

any 2750 w/
digital output

any 2750 w/4 to
20 mA output

any 2750 w/4 to
20 mA output

any 2750 w/4 to
20 mA output

any 2750 w/4 to
20 mA output

with internal preamplifiers*

Differential sensors
must use preamplifier
at sensor location;
otherwise, sensor signal
will be too erratic due to
high impedance signals

Other Mfr’s Instruments requiring
external preamplified signals**

2760-1, -2, -11, or -21

2760-1, -2, -11, or -21

2760-1, -2, -11, or -21

2760-1, -2, -11, or -21

2760-1, -2, -11, or -21

2760-1, -2, -11, or -21

Products

Other

Installation

Wiring &

Reference

Technical

Temperature/

Pressure

Graphs

of Terms

Glossary

Reference

Part No.

www.gfsignet.com

Index

97