Static Elimination is a big call for us. We have many amazing products that will eliminate your surface static with ease. Static can cause so many issues, we could (and have) write several blogs on this alone. EXAIR’s Gen 4 static eliminators (also called ionizers) can eliminate static charges. These shockless ionizers are electrically powered and produce a plethora of positive and negative ions. The charged surface then attracts the appropriate number of positive and negative ions from the ionizer to become neutral, or discharged.
The key behind this is the high voltage power supplied to the Ion Points. The power supplies that we offer, are the only power supplies that are compatible with our ionizing products. Each outlet supplies 5kV. This high voltage powers the Ion Points in the products to create the Ions mentioned earlier.
The power supply is sold with either 2 or 4 ports to power that many Gen 4 Products. Each one has a selectable input voltage of 115VAC or 230 VAC, an input current of .2/.1 A max, and a frequency of 50/60Hz. They also have a lighted power switch for easy visualization of power. This light is on a rocker switch, and this can be replaced – here is a blog to do this: How to replace the rocker switch on the Gen 4 Power supply.
The electrical costs associated with generating compressed air make it the most expensive utility in any industrial facility. In order to help offset these costs, it’s imperative that the system is operating as efficiently as possible. I’d like to take a moment to walk you through some of the ways that you can work towards making your compressed air system more efficient.
The first step you should take is to identify and fix any leaks within the distribution piping. According to the Compressed Air Challenge, up to 30% of all compressed air generated is lost through leaks. This ends up accounting for nearly 10% of your overall energy costs!! To put leaks in perspective, take a look at the graphic below from the Best Practices for Compressed Air Systems handbook.
Compressed air leaks don’t just waste energy, but they can also contribute to other operating losses. If enough air is lost through leaks, this can also cause a drop in system pressure. This can affect the functionality of other compressed air operated equipment and processes. This pressure drop can affect the efficiency of the equipment causing it to cycle on/off more frequently or to not work properly. This can lead to anything from rejected products to increased running time. With an increase in running time, there’s also the need for more frequent maintenance and unscheduled downtime.
You can perform a compressed air audit in your facility using an EXAIRModel 9061 Ultrasonic Leak Detector. If you’d prefer someone come in and do this for you, there are several companies that offer energy audit services where this will be a focal point of the process.
Speaking of maintenance, proper compressor maintenance is also critical to the overall efficiency of the system. Like all industrial equipment, a proper maintenance schedule is required in order to ensure things are operating at peak efficiency. Inadequate compressor maintenance can have a significant impact on energy consumption via lower compressor efficiency. A regular preventative maintenance schedule is required in order to keep things in good shape. The compressor, heat exchanger surfaces, lubricant, lubricant filter, air inlet filter, and dryer all need to be maintained. This can be done yourself or through a reputable compressor dealer. The costs associated with these services are outweighed in the improved reliability and performance of the compressor. A well-maintained system will not cause unexpected shutdowns and will also cost less to operate.
The manner in which you use your compressed air at the point of use should also be evaluated. Inefficient, homemade solutions are thought to be a cheap and quick solution. Unfortunately, the costs to supply these inefficient solutions with compressed air can quickly outweigh the costs of an engineered solution. An engineered compressed air nozzle such as EXAIR’s line of Super Air Nozzles are designed to utilize the coanda effect. Free, ambient air from the environment is entrained into the airflow along with the supplied compressed air. This maximizes the force and flow of the nozzle while keeping compressed air usage to a minimum.
Another method of making your compressed air system more efficient is actually quite simple: regulating the supply pressure. By installing pressure regulators at the point of use for each of your various point of use devices, you can reduce the consumption simply by reducing the pressure. This can’t be done for everything, but I’d be willing to bet that several tasks could be accomplished with the same level of efficiency at a reduced pressure. Most shop air runs at around 80-90 psig, but for general blowoff applications you can often get by operating at a lower pressure. Another simple, but often overlooked, method is to simply shut off the compressed air supply when not in use. If you haven’t yet performed an audit to identify compressed air leaks this is even more of a no-brainer. When operators go to lunch or during breaks, what’s stopping you from just simply turning a valve to shut off the supply of air? It seems simple and minute, but each step goes a long way towards reducing your overall air consumption and ultimately your energy costs.
Vortex Tubes are near the top of the list of the most interesting uses of compressed air: Cold (and hot) air, generated instantly, from a device with no moving parts. Why don’t we use them for EVERYTHING? It’s not that it CAN’T be done, but it can be impractical to do so. Consider:
While researching our Cabinet Cooler Systems, some callers will ask about using this technology to cool a space larger than an electrical panel, like a server room. I spoke with just such a caller once, who had 7.5kW worth of heat estimated in a server room that was under construction, and had been asked to research cooling solutions…so we did:
Since 1 watt equals 3.41 Btu/hr, 7.5 kilowatts equals 25,575 Btu/hr worth of cooling required.
Our highest capacity single Cabinet Cooler generates a cooling capacity of 2,800 Btu/hr, so we talked about ten of them, for ~10% safety factor, which was reasonable for the purposes of our discussion.
Each 2,800 Btu/hr Cabinet Cooler uses 40 SCFM @100psig, for a total of 28,000 SCFM. Using a common thumbrule that says a typical industrial air compressor generates 4 SCFM per horsepower, that means they’d need a 100HP compressor (or that much capacity from their whole system) just to run these Cabinet Coolers. Adding that cooling capacity to their HVAC requirements made more sense.
Of course, with every rule, there’s an exception: an independent crane operator carries a Model 3250 Large Vortex Tubewith him for cab cooling in the tower cranes he’s contracted to operate. While the US Department of Energy considers “personnel cooling” to be an inappropriate use of compressed air, the small fans typically found in these cranes’ cabs offer little comfort to an operator spending all day, 50 feet off the ground, in the summer heat of the Deep South!
Another common question regards the use of a Vortex Tube with another EXAIR product…the most common being an Air Knife. These callers want to blow cold air onto something, but instead of the conical and relatively small flow pattern the Vortex Tube discharges, they want to blow a curtain of cold air. The design & function of both the Vortex Tube, and the Air Knife, work against this idea:
The cold air has to exit the Vortex Tube at, or very near, atmospheric pressure. If it encounters much back pressure at all, performance (as measured by the temperature and flow rate of the cold air) will deteriorate.
An Air Knife, by design, is pressurized all the way to the point where the compressed air flow exits the 0.002″ thick gap. That’s far too much back pressure for a Vortex Tube to operate under.
Even if the Vortex Tube DID supply cold air, under pressure, to the Air Knife, the tremendous amount of environmental air entrained by the Air Knife would still result in a total developed flow temperature that was much closer to ambient temperature for the area.
One “workaround” for this is what we informally call a “cold air knife” – that’s when you plumb the cold air from a Vortex Tube into a length of pipe with a series of holes drilled along its length. Let’s say a building products manufacturer wanted to blow cold air across a 10ft wide continuous sheet of roofing material…because they did:
I recommended that they take a PVC (because it’s non-conductive and wouldn’t transfer heat from ambient as fast) pipe a little longer than 10ft, cap the ends, drill 1/8″ holes every inch (total of 120 holes).
From the table below, we see that a 1/8″ diameter hole can flow as much as 1.1 cubic feet per minute @1psig*, so 120 of those holes will pass ~132 cubic feet per minute worth of air flow.
Four Model 3240 Vortex Tubes were specified: when set to an 80% Cold Fraction, 80% of the 40 SCFM that each will consume, or 32 SCFM, is directed to the cold end. 32 SCFM X 4 3240’s = 128 SCFM. Close enough. They plumbed those 4 Vortex Tubes at approximate equal distances along the length.
AModel 3215 Medium Vortex Tube supplied @100psig will flow 10 SCFM worth of cold air when set to a 67% Cold Fraction**, which will give us a curtain of cold air that’s a little more than 71°F colder than the compressed air supply:
If you’ve got an application involving the need for cold air, on demand, EXAIR has a variety of products that’ll do just that. Give me a call to find out more.
Russ Bowman, CCASS
Application Engineer EXAIR Corporation Visit us on the Web Follow me on Twitter Like us on Facebook