Efficiency is in the Air
The intelligent use of energy is a high priority for customers. In fact they do
not need to focus on new technologies if they manage to establish new approaches
to use energy efficiently. Within pneumatics combining an intelligent control
with sophisticated pneumatic components already increases a system�s efficiency,
as energy is used more effectively. This combination enables an increase in
efficiency of more than 25 percent.
At first glance, the work of a pneumatic cylinder appears simple. Driven by air
pressure, it moves up to the desired position, exerts the pre-calculated amount
of pressure and returns to the starting point. However, what seems to be a
simple back-and-forth movement, lacking the possibility for a large improvement,
can be accomplished with significantly less energy and maximum protection of the
material by using a situational control.
Savings with intelligent control
An actuator�s motion sequence is divided into various phases in pressure
profiles. Depending on the application, a cylinder�s pre-stroke could be
initiated at 6 bar in order to overcome static friction and inertia. A lower
pressure is then sufficient for further movement in order to arrive at the end
position. As a rule, needed force only has to be applied at the end cylinder
movement. Even if the section, over which the pressure is reduced, appears
short, it is still sufficient to optimize the motion sequence and minimize hard
stops. Small savings over many thousands of repetitions of an individual
movement add up to a noticeable increase in efficiency for the entire process.
Since every application has individual characteristics, energy-efficient
procedures require extremely precise and intelligent pneumatic valves. Rexroth�s
ED series combines innovative proportional valve technology with digital control
electronics. Every unit comprises a direct drive including a proportional
solenoid and a pressure sensor, as well as integrated control electronics.
Valves and electronics work together
Electronics can maintain set points exactly and control processes intelligently
using a combination of an integrated sensor and fast-switching pneumatic valves
with a direct force transmission. Force, flow rate, rpm, position or cylinder
speed can be controlled in order to achieve optimum results with maximum
repetitive precision. The cylinder stroke can be returned in idle at a lower
pressure. Through skillful pressure control, this leads to a hardly noticeable
deceleration, yet positively affects the consumption of compressed air. In
comparison with unregulated usage, energy savings of more than 25 percent can be
achieved if the correct pressure is used consistently for the respective task.
Due to integrated electronics, Rexroth�s electro-pneumatic pressure regulators
work decentrally as well as with a master control. Diverse field bus options are
available, along with standard analog interfaces. The modern valve system of
plug & work components minimizes the engineering effort for pneumatically
controlled machine functions. Their use is very simple, because no additional
adjustments are necessary for commissioning. Integrating various functions into
a single component offers an additional dynamic advantage in complex machines,
as the decentralized control takes on many tasks independently, thereby reducing
run times.
Precision also in continuous operation
The pressure regulators have very modest requirements in terms of compressed
air. The proportional solenoids open and close the valves continuously and
without leakage even at normal air quality with 50 μm filtration. The integrated
pneumatic return compensates for fluctuations in the supply network and other
disturbance variables. Rexroth�s ED line covers the entire range of compressed
air applications, from 100 l/min up to more than 2600 l/min.
Economics and sturdiness make intelligent electro-pneumatics attractive for
tasks such as counter balancing, force compensation, pressure surface
monitoring, paint metering, or press-fitting. Whether it is controlled airflows,
positionable drives or speed control, no energy is dissipated by the pneumatics
during acceleration and braking, which ensures excellent repeatability in
continuous operation. Precision is thus guaranteed even in very difficult work
environments.
Short paths prevent losses
Energy can be lost at many points in a system that generates and uses compressed
air. Rexroth offers modern pneumatic components without leakage loss so they
maintain pressure in the line. Due to its compact dimensions and minimal weight,
the LS04 valve terminal system can be mounted directly on moving parts, such as
those in handling systems. This concentration of pneumatic functions in the
smallest spaces prevents air losses caused by long line lengths from the control
cabinet to the pneumatic drive and additionally reduces cycle times.
Increasing efficiency is one of the most important tasks for the future of
machine and system engineering. On the one hand, minimal consumption leads to
minimal emissions; on the other, higher energy efficiency lowers operating
costs. Calculated over the life cycle, these eat up more than half of the total
costs. As energy becomes ever more expensive, its efficient use will become a
decisive factor for a company�s competitive ability, because costs per unit will
rise more slowly in highly efficient systems.
Investments in energy-efficient methods therefore offer a good return already in
the short term. However, they also require that we rethink proven methods and
critically assess everything from individual components to the entire system.
Only an intelligent interaction of all individual elements opens up the complete
savings potential, as is demonstrated in the development of traditional
pneumatic valves into electro-pneumatic control valves.
Bosch Rexroth Canada is the Canadian partner company of Bosch Rexroth AG, one of
the world�s leading specialists in the field of drive and control technologies.
Under the brand name of Rexroth the company supplies more than 500,000 customers
with tailored solutions for driving, controlling and moving machinery used in
industrial and factory automation as well as in mobile applications. As The
Drive & Control Company, Bosch Rexroth develops, produces and sells components
and systems in more than 80 countries. In 2007 Bosch Rexroth AG, part of the
Bosch Group, achieved sales of about 5.4 billion Euro with approximately 33,000
employees.
Company Information:
Bosch Rexroth Canada
Ontario, CANADA
www.boschrexroth.ca
[email protected]