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What's next for compressed air tech

Feb. 20, 2019
New offerings will help your facility reduce artificial demand, achieve greater system control, and realize new levels of compressed air efficiency.

The International Manufacturing and Technology Show (IMTS) that took place in Chicago in September presented great opportunities to learn about new innovations in industry and talk to important players in the world of compressed air efficiency.

The IMTS show is one of the largest expositions of its kind in the country, taking up 1.4 million square feet in Chicago’s McCormick Place. The show focuses on materials manufacturing technology, with 2,563 companies from around the world exhibiting in 2018. This latest show was a record-breaker in terms of attendance, with more than 129,000 on hand people to view an array of eye-popping displays. The 2018 edition also eclipsed previous records for floor space and exhibitors – it seemed, everyone who was anyone in the manufacturing field was there. The big draw for me was the Hannover Messe USA displays – in particular those in the COMVAC section (COMpressed air and VACuum). Having been to the big Hannover Messe show in Germany the past two times it was held (biennially), I was excited to see the same on home soil.

Initially I felt like a kid in a candy shop, with so much technology to see. After deciding to focus my attention on the Hannover Messe USA and COMVAC displays, I was a bit disappointed to find that the compressor and vacuum section had only 24 displays, and none of the major North American compressor brands was represented there. It was good to see that both Kaeser and Sullair had booths in other areas of the show, however.

The focus in my line of work is energy efficiency in compressed air systems, and as such I am always on the hunt for products and services that can help my clients save money. Attendance at a show like this puts me in touch with latest advances in the field and provides the opportunity for serendipity, where I can find something useful that I didn’t expect to see.

Putting it all together: Efficiency, safety, and savings

The main COMVAC area paled in comparison to its big brother, the massive Hannover Messe COMVAC in Germany, but I did find some products that would help my customers. A few of my customers in the food industry wash down their equipment every day during a regular sanitation cycle. This is a problem for electrical panels; sometimes the panel door seals allow water to enter and contaminate or short electrical circuits. Some customers have resorted to hooking the problematic panels to their compressed air system and pressurizing them to prevent water ingress. One of my clients consumes more than 100 cfm of 100 psi compressed air to pressurize its panels to only a few inches of water pressure. Because of compressed air’s energy intensity, this is costly for them, consuming more than $17,000 in electrical costs per year for something that should cost only a few hundred dollars at most.

Other customers of mine find that their panels full of electronic components running their production machinery sometimes overheat due to the density of the heat-producing components. The environment in some of these plants is hot and dusty, and fan-powered ventilation blowers run the risk of introducing contamination into the sensitive circuitry. Some customers use compressed-air-powered enclosure coolers that consume, for example, about 20 cfm of compressed air to produce 2,000 btus of cooling (about 4 kW in equivalent electricity per cooler). Two exhibitors at the show, Pfannenberg and Hoffman offer suitable refrigerated cooling alternatives that could be bolted to the side of these panels to provide the same level of cooling for about one-fifth the energy cost. There were also panel guards offered that could be fitted to panels in a washdown environment to waterproof the seals to protect internal electronics. Efforts are under way to convert two of my clients’ panels to this type of cooling – the electrical savings for these projects will more than pay for my time spent at the show.

Not far from the COMVAC displays in the Hannover Messe section was a display of SMC pneumatics products. I was very impressed with one high-tech item designed to be used on complex pneumatic-powered machines to detect abnormal leakage. The Automatic Leak Detector system is designed to be fitted on the input of a machine and taught the machine’s normal pressure and flow profile. If something inside springs a leak, the detector notices a change in the characteristics and sends an alarm. This detector will be extremely valuable in industries where the production machinery is especially complex and high-speed. Detecting leaks in these conditions using alternative methods such as ultrasonic leak detection systems tends to be very difficult because of the number of pneumatic exhaust ports firing in machine-gun fashion.

Silvent had a nice display of the company’s specialty blow nozzles; more are developed each year. It is common to see blowing using copper tubing or pipes with holes drilled in them to clean or cool things in industrial plants. These homemade devices typically blow wastefully using a “shotgun effect” where very little of the compressed air emitted from the device actually does any good by hitting the target. The specialty nozzles provide a more-focused blow, using less compressed air, while operating quietly, saving energy, and reducing the sound pollution that is often a problem in industrial plants.

Smarter compressed-air control

Kaeser Compressors had a presence at the show but was located in a different area. On display in the Kaeser booth was the company’s impressive Sigma Air Manager 4.0 Master Controller, a recently upgraded version of Kaeser’s powerful SAM controllers. I was familiar with the older versions of the controllers, as some of my clients had installed these in the past, but the new versions are extremely intelligent. The controls, rather than simply operating on fixed pressure settings and a preprogrammed machine operating order, now constantly look at current conditions on the compressed air system and automatically optimize compressors based on the best use combination. The unit has the ability to evaluate the efficiency points of variable-speed-drive-controlled compressors, with internal algorithms programmed to find the best efficiency points of multiple units – even taking into account switching frequencies and unloaded run time of fixed-speed units. Should a better combination of compressors be identified to be more efficient, the system will switch units to reduce operating costs. The control constantly learns about the system and adjusts accordingly. 

Built into the controller are interfaces that allow remote monitoring (even wirelessly) of the compressed air system on any internet-connected device that has access to the network so operators and managers can ensure that the system is working adequately and receive warning of important status changes. The controller also produces nicely formatted reports about the system’s efficiency and costs to help inform energy management efforts in the plant. A big improvement from older SAM versions is super-fast Ethernet communication. The old serial ports we used to have to rely on left many of us waiting for hours while downloading data collected by the control’s data logger.

Kaeser has also improved the ASD range of its variable-speed-drive compressors by adding a motor type called “synchronous reluctance.” This induction motor has a specially designed rotor that functions in a way similar to a synchronous motor, reducing losses, especially at low rotational speeds. A typical problem with variable-speed-drive compressors is that as the motor turns more slowly, the efficiency of the compressor gets worse. Some of this efficiency turndown at partial loads is a factor of the poor efficiency of standard induction motors. Kaeser reports significant improvement in overall compressor efficiency using this motor, especially at partial loads, resulting in a flatter and lower efficiency curve. A quick check of the compressor CAGI sheets of various models confirms that the variable units have extremely good numbers and profiles that are constant over the variable-frequency range.

Sullair also had a booth at the show; it was there that I was able to talk to Brit Thielemann, product manager of Sullair’s stationary products division. Thielemann was extremely proud, for good reason, of Sullair’s new LS series compressors, available in fixed-speed, variable-speed, and variable-capacity models. The LS model compressors have undergone their first major redesign in many years in the lifespan of these solid Sullair machines. The units now have a simplified design that eliminates many of the external pneumatic tubes and porting of the old design. The air ends and redesigned rotor profiles of these machines are larger and more efficient than their older counterparts. And the machines sport an impressive new touchscreen controller that brings all important internal parameters out onto a bright, eye-pleasing display. Built into the controller is an interface that allows as many as 16 compressors to be connected and coordinated within a single group on a common pressure band.

One of the most interesting innovations of this LS series is the introduction of the electronic spiral valve control for the variable-capacity machines. Previous versions of spiral valve control used a pneumatic method of adjusting the valve, which reduces the capacity of the compressor by opening up ports inside the screw housing, reducing the flow output of the machine to match the current loading conditions. This capacity control is a good way to part-load a compressor, allowing the unit to keep producing air but at capacities as low as 50% output before unloading. In previous versions, the spiral valve position was dependent on a pressure band about 10 psi wide when operating between fully open and fully closed valve positions. The new control operates using a stepper motor actuator to move the valve position.  This provides a precise, single-pressure target set point through the valve’s full operating range. This type of control is not unlike the control provided by a typical variable-speed-drive compressor.

One of the disadvantages of variable-frequency drives is limited drive life in extremely hot and dusty conditions with poor ventilation. When faced with these conditions, the new spiral valve control can provide VSD-like capacity adjustment but through a hardened method that can withstand harsh environments. Although the turndown of the spiral valve is only 50% – compared with typically 80% for most competitive VSD machines – the new LS controller allows two or more spiral valve machines to be coupled together to provide excellent turndown and good multiple-machines control through sharing of the load. Having a precise set point rather than a 10 psi band keeps the average pressure low, reducing the artificial demand that wastes energy at higher pressures.

Thielemann reported that the LS series machines have recently been tested through Compressed Air and Gas Institute’s third-party verification program, and the machines passed with flying colors.

In all, the IMTS experience was quite beneficial in helping find some product innovations that will save money for years to come. The experience again showed me that poking my nose outside my office and into the industrial show experience allows me to grow my product knowledge and make some great discoveries. Well worth the experience!

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