stuck before the situation affects the
process or final product.
Wireless will connect manual valve
feedback to an increasing number of
automated controls. The result will be
improved operations and safety; one
example is adding a manual clean-out
valve to an interlock where filling the
chemical reactor will not occur unless the
valve is closed. This simple change does
three things to improve process reliability: it protects product quality, it protects
against scrap or rework, and it protects
against clean-up actions. The end result
is a more reliable process and greater
confidence that all is well.
Wireless also enables reduced
resources needed to verify a valve’s state.
Many mistakes are made in batch
processes where valves are left in the
wrong state. Therefore, increasing the
amount of valve information leads to
greater assurance, providing proof to
management that operations and safety
improvement actions are achieving
desired results. Using wireless to improve
awareness has already proven itself in the
chemical industry.
Early successes in wireless lead the
way in addressing other operational pain
points, as well. The industry-wide need
and desire to increase safety means the
percentage of manually operated blind
valves will decline while valves equipped
with feedback will increase.
ADVANTAGES OF VALVE
AUTOMATION
Manually operated valves are automated
for three primary reasons. First, moving
the valve may require too much manual
effort. Second, it may be desirable to
eliminate having personnel in dangerous
conditions such as precarious heights or
hazardous environments. Third, it might
be necessary to reduce complexity and
time needed to coordinate valve adjustments during plant operations.
Valve uses are divided into two uses or
categories: on/off or control. On/off
valves are generally used for bypass,
sampling and batching, as well as used in
series with a control valve for shutdown
or tight shutoff.
A large number of operations have
some on/off valves that are not moni-
tored for position—they are equipped
solely with a solenoid to move the valve.
About half of these semi-automated
valves have no position feedback
because of cost or practicality of obtain-
ing the position feedback information.
Obtaining feedback for an on/off valve
has required the use of two sets of wires,
one for open and another set for closed;
these wires are connected to simple dis-
crete inputs at the control system.
Until now, targeting existing valves
for improvements has been rare because
it has been a hassle and headache to
make changes to wiring infrastructure as
well as control I/O. Wireless is already
changing approaches to new projects and
installations because it eliminates wiring
and creates simplicity. But the largest
opportunity for improvement is with
valves already installed. Knowing more
about a valves’ health enables better
decisions and faster maintenance. It is
just as simple and easy to achieve significant improvements on these old valves as
with new projects. Facilities that implement wireless feedback have the competitive advantages of operating cost reductions, improved product quality,
increased production volumes and
increased levels of safety.
ADVANTAGES OF WIRELESS
In places where valve position monitoring
does not currently exist, wireless monitoring provides a way to use monitoring
technology with minimum risk.
Other compelling advantages of wireless over wired monitoring include:
; Wireless is easier to install because
there are no wires. The devices can
be battery-powered and operate for
5 to 10 years in process environments. WirelessHART position
feedback devices, for example, are
very energy efficient and update
rates of 4 seconds will still provide
10 years of service without changing the power module.
; Wireless devices can be implemented at 10% to 20% of the cost
of wired. An on-going cost of battery-powered devices exists; however, with life expectancies of 7 to
10 years, that burden is reduced
considerably.
; Wireless instruments can be implemented in a matter of minutes and
require fewer people for the
process. Remember, battery-powered devices have no conduits or
wiring at all—they are simply
mounted to the valve. Feedback
from a manual valve has incredible
value, especially for safety. This is
why retrofitting existing valves
makes sense.
