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Features
·
Guaranteed Longest Lasting
Sensors Available with performance guarantee *
·
Sensors are compatible with most
existing pH/ORP Meters, Transmitters & Analyzers **
·
Application Specific Engineering
results in optimum Lifetime & Performance ***
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Integrated Temperature
Compensation, Preamplifiers & Solution Ground Elements
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Solid State Reference System offers superior resistance to Fouling
& Dehydration
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Applications such as Acid/Fluoride,
Hi-Temp, Saturated Sodium and Sulfide Resistant are available as standard
options
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Custom Applications are available,
often at no additional charge
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Most Installation Styles are
Supported Including: Immersion, Twist Lock, Valve Retractable
& Sanitary
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Available in a wide range of plastics,
from cost effective CPVC to thermally & chemically resilient ULTEM®
and PEEK thermoplastic
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High Pressure Applications up to
100 psi for Valve Retractable & 150 psi for Inline Installations can be
supported for continuous use
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Operating Temperatures from -30
to +150 ºC (-22 to +302 ºF) can be supported
for continuous use
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Case Study No. 14 –
pH & ORP Measurement in Wastewater
Competitively Priced High
Performance pH & ORP Sensors that can retrofit to almost any existing
pH/ORP Transmitter and Controller and Installation Style
Virtually Maintenance Free
conductive polymer solid state reference system minimizes cleaning
requirements, and allows for aggressive chemical and mechanical cleaning
Thick Wall pH glass elements are
nearly impossible to break during normal process operation, cleaning and
calibration
Flat Wall pH Elements offer
excellent “maintenance free” operation for slurry solutions
Multiple sensor body
configurations allows sensors to retrofit to nearly any installation
Embedded temperature
compensation elements, stainless steel solution (liquid earth) grounds, and
conventional & differential high impedance CMOS operational amplifiers
(preamplifiers) allow connection to almost any existing pH/ORP transmitter or
controller
The Problem
A
waste water treatment company wanted to reduce the maintenance time on their
wastewater sensors and standardize on one pH vendor, in spite of having pH
and ORP transmitters from a variety of vendors. The build up of calcium
hydroxide on the reference and pH elements from the neutralization process
required rigorous mechanical cleaning (resulting in sensor breakage), because
the previously used sensors could not handle the use of strong acid solutions
to remove the calcium deposits without significantly shortening its
lifetime. The previously used multi-component re-buildable sensors required
significant maintenance (refilling salt bridges, etc.), reducing the
wastewater crew’s efficiency. pH and ORP transmitters from various
manufacturers meant purchasing pH and ORP sensors from many vendors, causing
stock levels to be high.
The Solution
Integrated, sealed,
“maintenance free” pH and ORP sensors that could retrofit to all of the existing
pH and ORP transmitters were required. Low impedance pH glass elements were
chosen for pH meters with poor internal mV amplification (such as Johnson
Yokogawa). Flat pH elements were chosen for processes were this would
minimize the build-up from inline caustic service. The non-porous conductive
polymer solid state reference junction reduced the cleaning requirements and also
made the sensors more resilient to occasional periods dehydration. The
customer was able to use strong (half-dilute) hydrochloric acid to remove the
calcium deposits and thus minimized breakage by reducing the frequency of
mechanical cleaning. Service lifetime improved up to one to two years, with
little change in the unit price of the individual sensors. Faulty
transmitters were replaced with simple menu driven two or four wire
transmitters. The new transmitters were configured such that the currently
stocked sensors could interface to the new pH and ORP meters.
The pH Sensor Used:
Model: PN 6011-3000JYC-25 pH “Conventional” Sensor
Description: ¾”- ¾” MNPT Immersion CPVC/PVC Bodied Low Impedance
Conventional pH Sensor with integrated 3000 Ohm Balco Temperature Compensator
& Solution Ground; 25 feet of cable; tinned lead wires only to connect
directly to most Johnson Yokogawa pH Transmitters
The Alternate pH Sensor used
for more Rugged Service:
Model: PN 6331-GLI5-10 “Differential” pH Sensor
Description: ¾”- 1” MNPT Immersion ULTEM Slurry/Viscous Material
Resistant pH Sensor; Integrated 301 Ohm Thermistor TC, SS Solution Ground
& GLI Compatible 5-wire differential preamp.; 10 feet cable; to connect
directly to most Great Lakes pH Transmitters & Controllers
The ORP Sensor Used:
Model: PN 6811-0000-25 ORP “Conventional” Sensor
Description: ¾”- ¾” MNPT Immersion CPVC/PVC Bodied General
Purpose Conventional ORP Sensor with No TC Assembly; 25 feet cable; to
connect to any ORP Transmitter or Controller that can accept BNC or tined
lead wire connections (All Major Manufacturers supported)
Choosing the Correct pH/ORP
Sensor
1.
Choose a sensor body type that
suits the physical parameters of the
installation (refer to the Configurations
Portion of pH/ORP and Ion Selective webpages).
2. Choose
a sensor that suits the process application, temperature,
chemistry, and physical
parameters of the installation (refer to Sensor Selection Guides
and call factory or local sales agent for support)
3. Choose a sensor housing material that is compatible
with the process chemistry, temperature & pressure (refer
to Chemical Resistance Charts as posted under the Technical
Documents portion of the website).
4.
Select suitable temperature compensation element, solution
ground & integrated preamplifier based upon the mating pH/ORP Instrument (refer to Electrochemical Instrumentation
Page & ask for factory support).
5.
Specify the required
cable length based
upon installation
location (refer
to Part Numbering Guide).
*
Subject to application qualification and review by an approved ASTI sales
agent and/or factory. Performance guarantee is posted on the ASTI online
application questionnaire page.
**
See list of supported pH/ORP/ISE Instruments webpages as posted on the ASTI website.
***
Completion of Application Questionnaire form is required. Other restrictions
may apply.
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