Chemical Engineering November 2022 - 13

Siemens
FIGURE 2. Siemens' P320 and P420 transmitters are available with a highprotection
cell for use in processes that contain highly toxic chemicals, such
as phosgene
ent atmosphere, Siemens offers a
new high-protection measuring cell.
" Adequate sealing in highly toxic
applications is always a concern so
you can't rely on tapered threads. A
welded or gasketed seal is necessary
to prevent unintentional leaks
in these applications, " says McNutt.
" In response, we developed a highprotection
cell that adds an extra
stainless-steel-welded barrier between
the process and the electronics.
That is then filled with glass to
prevent more permeation and provide
another layer of protection. "
He continues, " The key to this development
is not just protecting, but
also detecting, so in addition to preventing
the escape of toxic materials,
there is a sensor inside the device
- in the form of a small conductor
strip that will erode if it comes in
contact with the process material -
that will alert users if the primary seal
has failed. " This high-protection cell
is available on Siemens' P320 and
P420 transmitters (Figure 2).
To deal with thermal-induced drift,
another common challenge in the
chemical process industries (CPI),
Endress+Hauser offers TempC, a
unique diaphragm-seal membrane
that helps increase reliability and accuracy
of the measurement in pressure
and differential-pressure applications
where
thermal-induced
drift is known to skew the measurement.
" Typically, when a transmitter is
placed in an area where the ambient
temperature varies, the fill fluid in the
capillary of a pressure device expands
and contracts accordingly, " says
Riley. " The problem is that the expansion
pushes against the diaphragm,
which can only give so much, and the
remaining expansion is forced against
the pressure
sensor, which
will then indicate
a false change
in pressure. The
TempC membrane,
without
giving up durability,
can absorb
more expansion
and contraction,
reducing thermal
drift and providing
a more reliable
and accurate measurement, regardless
of what's happening with the
ambient temperature. "
Also dealing with ambient-related
influences on differential pressure applications
that typically require insulation
or heat tracing to avoid thermalinduced
drift, VEGA developed a new
electronic differential pressure (EDP)
technology. " While more traditional
differential pressure applications
sometimes require insulation and heat
tracing to avoid thermal-induced drift,
our EDP technology provides an alternative, "
says Eric Moore, chemical
industry manager for North America,
Eastern U.S., with VEGA. " EDP features
two separate pressure sensors
connected electronically so they can
share information. Because the wires
are electronic, they are not susceptible
to environmental conditions the
way traditional
differential-pressure
transmitters would be. While it's not
a solution that can be used in every
differential-pressure scenario, where
it fits, it is a fantastic solution
to eliminate ambient-related
influences on the transmitter,
which helps boost reliability
of the measurement. "
Emerson
Benefits of digitalization
" Digitalization is changing
the landscape of the CPI
[chemical process industries]
and users need access
to more data to run the plant
more efficiently, so they are
looking to add more devices
in a cost-effective way, " says
Emerson's Burton. " Wireless
pressure transmitters can
deliver quick instrumentation
measurement points
without the cost of wiring,
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providing the data needed to improve
operations. These devices can
be installed in hard-to-reach areas
or in dangerous plant environments.
This makes reliable pressure measurement
very important in light of
efforts to improve safety by minimizing
the time plant personnel spend in
the field. "
In addition, wireless-enabled pressure
transmitters allow for remote
configuration of the device while providing
access to diagnostic information
without having to physically connect
to the device, continues Burton.
" Operators in the CPI often lack insight
into the health of their pressure
transmitters, so diagnostic alerts
transmitted via the HART protocol
can help users identify the need for
maintenance before measurement
issues result in process downtime, "
he says. Further, investments in advanced
diagnostics, such as loop integrity
and plugged impulse line detection,
such as are available with the
Rosemount 3051 transmitter (Figure
3), help users detect issues in delivering
an accurate reading to host
systems. These diagnostics identify
issues that could result in the control
system receiving incorrect measurements,
potentially leading to safetyand
quality-compromising decisions.
McNutt from Siemens adds that
another recent development includes
the addition of on-board data logging
in pressure transmitters. " This can
be built into the transmitter and independent
from the distributed control
FIGURE 3. Advanced diagnostics, such as loop integrity and
plugged-impulse-line detection, such as are available with Emerson's
Rosemount 3051 transmitter, help users detect issues in
delivering an accurate reading to host systems
NOVEMBER 2022
13
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Chemical Engineering November 2022

Table of Contents for the Digital Edition of Chemical Engineering November 2022
