Industrial Energy Savings    

Pneumatics

Productivity is more reliable when equipment can be monitored to detect incipient failures and take corrective action before the plant goes down. But many devices, such as analog control valves, pneumatic valve terminals and field sensors, often do not offer diagnostic feedback, or it is not being used. This white paper describes how this problem is being addressed, and includes an example of pneumatic valve terminals that can monitor, among other things, open load or coil currents at the specific valve and pressure inside the valve terminal.
Over many years of reviewing industrial compressed air production machinery, of many types and styles, there is one common thread or complaint; “push-to-connect pneumatic tubing connections/fittings are a continual source of compressed air leaks and production interruptions.”  Probably seventy-five to eighty percent of push-to-connect type tubing fittings use flexible tubing selected for lower material cost and assembly rather than an alternate appropriate hard metallic tubing.  
The advent of manifold mounted, plug-in pneumatic valves has been a boon for machine builders. It allows them to mount complete valve packages in a safe and secure location on a machine. Using a D-sub connector, serial interface module, or similar single-point wiring system, all of the electrical control outputs can feed into one location on the manifold, greatly simplifying the wiring. Plumbing issues are reduced, since a single air pressure line can be used to feed a common pressure gallery. The same advantage applies to the common exhaust gallery. No longer would both a plumber and an electrician be required to replace a valve, since any valve can be replaced without disturbing electrical connections or plumbing lines.
Recently the capacity of the Las Palmas, California, waste water treatment operations were expanded by combining two plants and making one centralized filtration center. The new center expanded the flow capacity from 162,000 Gallons per Day (GPD) combined to 288,000 GPD when the manually controlled reclaimed water operations were updated to a state-of-the-art automated system. Reclaimed water from the plant irrigates local community green spaces. The new automated system ensures lower labor costs, consistent quality, and peak efficiency in the process of reclaiming waste water for irrigation.
Currently, and for good reason, much attention is being focused on the conservation of energy. Compressed air, like electricity and gas, is an energy resource. It has often been referred to as the third utility. As with all energy sources, our global environment demands that it be conserved and used wisely.
With the recent and future increases of the cost of energy, operating a wastewater treatment plant (WWTP) as efficiently as possible has become one of the most important factors that operators and managers are facing today. The implementation of a properly designed aeration control system has been reported by the United Sates Environmental Protection Agency to reduce aeration energy by 25 to 40 percent.
The fundamental question this article poses is, “Are factories happy with vendors of manufacturing equipment (using pneumatic components) dictating their energy footprint requirements?” Compressed air is a significant energy consumer in every plant and to fully understand the ramifications of the imbedded misconceptions with respect to compressed air supply, one must take into consideration the actual point of use needs for compressed air.
Back when gasoline was 35 cents a gallon, the term “environmental technology” was not well known. Engineers did not often promote the benefits of building low-energy consumption pneumatic valves among their peers. Recycling or conservation of resources was seldom discussed with any seriousness. In reality, the conversation was more likely to have turned to the muscle cars of the day and how much horsepower they would generate.
A plastics molding plant had engaged us to conduct an ‘on-site’ Energy Assessment of their facility. The annual ‘spend’ for electricity, natural gas, and water was about $3.2 million for this modern 275,000 square foot, fully air-conditioned facility. During the Review, several opportunities were identified and delineated in lighting, HVAC, process ventilation, the water systems and energy supply contracts. However, the most significant savings were in their compressed air system.
Machine builders aiming to improve the energy efficiency of their machines tend to focus on using energy media other than Pneumatics (typically Electro-Mechanical or Hydraulic) since Pneumatics, as traditionally applied, is viewed as inefficient due to factors like leakage and over-pressurization (i.e.: supplying a higher pressure in an actuator to accomplish a task which is endemic in practice). But they shouldn't. When generating and using compressed air, it's true that there are many places in the system where energy can be lost, however targeted measures within a comprehensive energy saving concept can prevent these losses and significantly reduce energy consumption at the machine level.
The PET industry is in a state of flux right now. A number of new bottle blowing facilities are being brought on-line. They are in the “discovery” phase right now as they realize how challenging the required compressed air systems are to manage – from an energy efficiency standpoint. The average high-volume stretch blow molder (SBM) working with PET usually has 2,000 to 4,000 horsepower of installed air compressors with the related energy costs running between $1 to $4 million per year. This typically represents 35-40% of the facilities’ total energy bill.