Rosemount Analytical 398, 398VP Data sheet

TUpH REFERENCE TECHNOLOGY ENSURES

LONG LIFE in processes that coat, foul, and poison
most other electrodes.

• Large Surface Area reference junction

• Helical Reference Pathway

• SILCORE™

1

Contaminant Barrier

SUPERIOR CHEMICAL RESISTANCE to tackle
the most aggressive applications, even CHLORINE
DIOXIDE in pulp bleaching towers.

• TITANIUM and TEFZEL

®2

sensor construction

• PEEK internal construction

• Choice of KALREZ

®2

or VITON

®2

seals

RESISTS ATTACK BY MOST ORGANIC SOLVENTS

FEATURES AND APPLICATIONS

The TUpH large area reference junction for mini­mal maintenance requirements: The reference junc-

tion provides an electrical connection between the ref­erence electrode and the sample, and helps maintain
a stable reference potential, regardless of the change
in sample pH. The TUpH reference electrode junction,
the entire plastic tip surrounding the glass pH elec­trode, maintains a steady reference signal even in the
dirtiest of applications because it resists plugging (a
common cause of pH signal drift). This large reference
junction area is made of micron sized reference path­ways used for ionic exchange so it resists plugging by
large particles and will continue to send a steady pH
signal, even in the dirtiest of applications. The TUpH
reference junction technology has been field-proven
for minimum maintenance requirements.

The TUpH helical reference pathway stops refer­ence poisoning. Ions diffuse through the reference

pathways and a charge is passed to the reference
element. The reference element must be protected

from contamination by poisoning ions such as sulfide,
mercury, cyanide, and ammonia or else the pH signal
will drift. The TUpH sensor's long internal helical
reference pathway hinders and slows down the rate
of contaminants migrating to the reference element
thereby providing a longer sensor life. This essential
component is constructed of PEEK thermoplastic,
one of the most durable materials available.

The entire line of TUpH model sensors now incor­porate the new SILCORE technology contaminant
barrier. This triple-seal barrier prevents moisture and

material impurities from migrating to the reference
electrode’s lead wire. By preventing these contaminants
from compromising the integrity of the pH measure­ment, sensor life is increased, especially at higher
temperatures. In addition, the SILCORE technology
provides added protection against sensor failure due
to vibrations and shock by transferring damaging
energy away from the glass-to-metal seal.

1

TUpH, ACCUGLASS, and SILCORE are trademarks of Rosemount Analytical.

2

Tefzel, Kalrez, and Viton are registered trademarks of DuPont Performance

Elastomers.

Models 398 and 398R

pH/ORP Sensors

Product Data Sheet

PDS 71-398/rev.F
October 2010

MODEL 398

INSERTION/SUBMERSION
DESIGN allows for variable insertion
depths and simple sensor removal
without cable twisting

MODEL 398R

RETRACTABLE DESIGN allows sensor to
be removed for calibration and maintenance
without process shutdown

Measured Range:

ORP: -1500 to 1500mV
pH: GPHT hemi bulb or GPLR flat bulb -

ACCUGLASS, 0 - 14 pH

Percent Linearity Over pH Ranges:

Reference: Permeable Tefzel with secondary helical

pathway

Wetted Materials: Titanium, Tefzel, glass, platinum

(ORP only), and choice of Viton or Kalrez

Process Connections: NONE

Must use 1 inch compression process connector
(PN 23166-00 or 23166-01).

Also, Model 398R can be inserted through a ball
valve

Cable: Standard integral 15 ft , optional 9.5 in. (for

Model 398R only);
Recommended Interconnect: PN 9200273

Maximum Process Pressure and Temperature:

250 psig (1825 kPa [abs]) at 212°F (100°C)

Maximum Pressure at Retraction or Insertion

(Model 398R only):

64 psig (524 kPa [abs]) Code 21
35 psig (343 kPa [abs]) Code 25

Minimum Conductivity: 75 µS/cm, nominal 100 µS/cm

Weight/Shipping Weight:

Model 398 sensor: 1.0 lb/2.0 lb (0.45 kg/0.9 kg)

Model 398R sensor:

Code 21; 2.0 lb/3.0 lb (0.9 kg/1.40kg)
Code 25; 3.0 lb/4.0 lb (1.40 kg/1.80kg)

*unless otherwise specified

pH range Hemi Bulb Flat Bulb

0-2 pH 94% 93%

2-12 pH 99% 98%
12-13 pH 97% 95%
13-14 pH 92% —

The ACCUGLASS1pH bulb means the Models 398
and 398R resist cracking and have near theoretical
response even at extreme pH values. A slotted tip
surrounding the glass bulb provides additional protec­tion against breakage. The sensor can be oriented
with the bulb directly in the stream, or it can be turned
ninety degrees, permitting the shroud to protect the
glass bulb from particles.

The TUpH™ reference junction and helical pathway
combined with the AccuG

LASS pH glass performs

exceptionally well in dirty, high solid applications and
requires only minimum maintenance. This is the tough­est pH sensor on the market and is still unmatched by
all other pH sensors.

The chemical-resistant construction of Tefzel

®

2

,
titanium, and the TUpH reference junction makes
Models 398 and 398R the ideal sensors for measuring
pH in harsh process liquids. Use Models 398 and 398R
to measure pH in sour water strippers, in pulp bleaching
towers that use chlorine dioxide, and in process streams
containing a variety of organic solvents.

All TUpH sensor models have been specifically
designed for improved life in harsh, dirty, and abrasive
applications such as lime slurry, waste treatment,
paper machine headbox, and pigment/dye applica­tions, where large quantities of suspended solids are
present. Various sensor materials, depending on the
sensor model, is available for a variety of different
application needs.

Models 398 and 398R are housed in a titanium tube.
The molded Tefzel

®

2

TUpH construction is offered

with a choice of seals (Viton

®

2

or Kalrez

®

2

).
Combining high quality materials with the TUpH refer­ence technology and ACCUGLASS pH bulb allows for
ultimate chemical resistance and makes Models 398
and 398R the perfect choice for measuring pH in
harsh, demanding processes.

Models 398 and 398R are available with 15 ft. of
cable for wiring directly to an analyzer/transmitter or
a remote junction box. The Model 398R retractable
sensor is also available with 9.5 in. of cable for use
with a sensor head junction box which attaches to the
sensor tube via a compression fitting.

A preamplifier converts the high impedance pH
signal into a stable, noise-free signal and must be

used with all pH sensors. The preamplifier can be in a
remote junction box or integral to the analyzer/transmit­ter. All TUpH Sensors are compatible with all Rosemount
Analytical and other manufacturers' instruments.

1

TUpH, ACCUGLASS, and SILCORE are trademarks of Rosemount Analytical.

2

Tefzel, Kalrez, and Viton are registered trademarks of DuPont Performance
Elastomers.

PERFORMANCE AND PHYSICAL SPECIFICATIONS FOR MODELS 398 AND 398R*

2 Rosemount Analytical

JUNCTION BOX IS OPTIONAL

Rosemount Analytical 3

Typical Mounting Details - Model 398R Retraction Version

Note: Sensor must be mounted at an angle between 10° and 90° above the horizontal.

Pipe tees and weldalets provided by customer.

4 Rosemount Analytical

Recommended Flow-Through and Insertion Installation for Model 398

1-1/2 inch Pipe Tee (PN 2002011) with 1 inch threaded connections

Insertion Installations for Model 398

Model 398 can be inserted into a tee, such as the one shown here (PN 2002011, 1-1/2 in. tee with 1 in. threaded process

connection), for angle or straight process flow. Other tees are available; see page 9 for part numbers.

PN 2002011