Concerns regarding the amount of energy that is con-
sumed—and potentially wasted—by industrial facili-
ties in the United States officially reached the highest
levels of the federal government on Aug. 30, 2012,
when Pres. Barack Obama signed an Executive Order
titled “Accelerating Investment in Industrial Energy
Efficiency.” Noting that “the industrial sector
accounts for (more than) 30 percent of all energy con-
sumed in the United States,” the Executive Order lays
out ways that increased industrial energy efficiency
can provide benefits to manufacturers, utilities and consumers while, at the same time,
improving the nation’s energy system, along with American manufacturing competi-
tiveness and job creation.
The Executive Order acknowledges what the operators and managers of industrial
manufacturing facilities have known for more than a decade: the modern-day definition of a successful industrial manufacturing operation is not one that only satisfactorily meets production quotas. Indeed, as utility costs have steadily risen and increasing
environmental consciousness has moved front of mind, a successful industrial operation is now one that delivers the required production rates in the most cost- and energy-efficient, as well as environmentally friendly manner.
Pumps, which are the second-most widely used machines in the world, play a critical
role in industrial operations around the globe and across a wide array of industries—
from chemical production and mining to water/wastewater treatment and hygienic
applications. In fact, according to the U.S. Department of Energy’s Office of Energy
Efficiency and Renewable Energy (EERE), pumping systems account for anywhere
between 27% and 33% of the total electricity used and consumed in the industrial sector.
Recognizing the importance of pumping systems in industrial applications, The
Hydraulic Institute has commissioned the writing of Optimizing Pumping Systems: A
Guide for Improved Energy Efficiency, Reliability & Profitability, which provides
instruction on how facility operators can recognize inefficient energy usage in their
operations and the steps they can take to remove these inefficiencies. Facility operators
must be fully aware that the initial purchase and installation cost of a new pumping
system is generally only a small part of the total cost to operate it over its lifespan. In
fact, over the 15 to 20 years that a typical pumping system is in operation it is the routine costs of energy, maintenance and other recurring expenses that are the primary
components in total lifetime cost. Therefore, maximizing efficiency when designing
and operating a pumping system is in the best interest of the facility and its customers,
as well as the environment.
Pump manufacturers realize the importance their products play in industry and have
taken great pains to design and develop pumping equipment that satisfies the increased
need for energy efficiency and reduced operating costs. This white paper will illustrate
how a revolutionary new air-distribution technology can help minimize air consumption and improve overall efficiency of reciprocating positive displacement air-operated
double-diaphragm (AODD) pump technology that is used in many of the world’s
industrial liquid-handling applications.
Invented in 1955, AODD pumps were specifically designed for use in a wide variety
of utilitarian liquid-handling and transfer operations. In the ensuing six decades,
AODD pump technology has gained a well-earned reputation for outperforming other
positive displacement pump styles—such as lobe, gear and progressive cavity—in the
most demanding liquid-transfer applications. That’s because the design characteristics
of AODD pumps enable them to run dry, maintain a suction lift up to 30 feet ( 9
meters), withstand deadhead conditions without damage, operate while completely
submerged and pass solids up to 1-3/8 inches ( 35 mm) in size, all while meeting most
flow requirements and requiring little maintenance.
While the operation of an AODD pump has basically remained constant for the past 60
years, improvements have been made in the pump’s air distribution system (ADS) that
addresses its rate of air consumption in relation to the product flow rate and how much
air can be wasted during the pumping cycle, with that wasted air resulting in an added
cost for the plant operator. While these savings are important for the plant operator,
they are actually modest when looking at the total volume of air that is used for these
There remains an opportunity for more significant savings. During the time period
from the end of each stroke to the completed shift of the valve, the air is allowed to
“overfill” the air chamber without any corresponding displacement of fluid. The rate
of this “overfilling,” which is defined as wasted compressed air, can be more adequately controlled. Attempts at improving the ADS in order to eliminate overfilling
have included the incorporation of a control dial that “sets” the pump’s operation at a
point that optimizes both air consumption and flow rate. However, these control dials
need to be manually adjusted by the operator after identifying the point where air
usage and flow rate are both at their most efficient, which can be time-consuming and
place an undue burden on the operator.
Most recently, a new generation of ADS has attempted to eliminate overfilling in
AODD pump operation. This next-generation ADS technology claims to prevent overfilling by cutting off the air supply to the air chamber before the end of the pump
stroke. There are two shortcomings, however, in this approach. First, this ADS technology is electronically monitored and controlled, rather than mechanically actuated,
which raises an entirely different set of energy usage, maintenance and operational
concerns. Second, this electronic ADS technology requires time to “learn,” meaning
that every time the pump is turned on, the electronic system needs a “learning period”
of 30-40 seconds, where it monitors the operation of the pump before it can estimate
when to cut off the air supply prior to the end of the stroke. This can result in erratic
and inconsistent flow rates for up to 40 seconds and a corresponding waste of air, a
drawback that is compounded in dosing operations that feature constant on-off cycles.
So, while AODD pump operation has come a long way in terms of air consumption,
thanks in large part to the invention of the signaled ADS, test pumps fitted with data-acquisition equipment show that air is still being wasted due to overfilling and that
there is the potential for additional energy-saving gains to be realized.
Jim Wilden invented the AODD pump in 1955—he was looking for a quick, easy way
to pump water out of a flooded workshop. The resultant AODD pump technology led
to the formation of the Wilden® Pump & Engineering Company, Grand Terrace, CA,
USA. Today, Wilden, which became a founding member of the Dover Corporation’s
Pump Solutions Group (PSG®) in 2008, continues to design and manufacture cutting-edge AODD technology for use in many industries.
The company has maintained its position because efficiency innovations have been
part of the Wilden DNA since Jim Wilden invented AODD technology.
This commitment to innovation has led to the creation of the Pro-Flo® SHIFT Air
Distribution System, which is not just an incremental improvement in ADS technology, but a true game-changer, one that presents an entirely new way of looking at how
pneumatic pumps operate.
As mentioned, the inefficiency in traditional ADS operation is the time delay the
AODD pump experiences when pressurized air is switched from one air chamber to
the other air chamber, which leads to overfilling of the air chamber, with the excess air
immediately wasted when it is subsequently vented into the atmosphere.
To combat this overfilling, the Pro-Flo SHIFT restricts the air flow into the air chamber near the end of each pump stroke so that only enough air is introduced to keep the
pumping process going. This is accomplished through the incorporation of an air control spool that automatically meters the air to prevent overfilling with no reduction of
product yield. The result is reduced air consumption while still maintaining maximum
operational efficiency and flow rates.
This mode of operation eliminates the need for the
operator to manually adjust the pump for efficiency
since the ADS automatically does it. This creates a
new efficiency point in AODD pump operation high-
lighted by improved energy use with no loss of flow
rate. Additional benefits of the Pro-Flo SHIFT ADS
Reduced total cost of ownership
• Faster setup time
• Ease of maintenance
• Drop-in configuration capability
• Ability to be retrofitted into existing Wilden AODD pumps
Shifting Your Perception of AODD Pumps
Revolutionary new air distribution system enables air-operated double-diaphragm (AODD)
pumps to set new standard in energy-efficiency, as well as optimized production