The EXAIRSuper Air Knife is the most efficient compressed air knife on the market. We know this because we’ve tested them, and our competitors’ offerings, for performance, using the same instruments, controls, and procedures. We’re not going to publish data that we can’t back up, and that’s a fact.
They’re also ideally suited to a wide variety of applications – they come in lengths from 3 inches to 9 feet long (and can actually be coupled together for uninterrupted air flows of even longer lengths,) a variety of materials for just about any environment. But the best thing about our Super Air Knives is how you can adjust the air pressure and flow to complete a wide variety of tasks. You can adjust them in two different ways, Replacing or adding Shims, or regulating the incoming air pressure.
Changing out your shim!
A larger shim gap will give you higher flow and force from your Air Knife. Honestly, the 0.002″ shim that comes pre-installed in all of our Air Knives is perfectly suitable for most blow off applications, and appropriate air supply conditions are the first thing you should check for before going with thicker shims, but if you do indeed need a boost, a thicker shim will indeed give you one…here’s a blog with the video to show you how it’s done:
Another advantage to having a Pressure Regulator at every point of use is the flexibility of making pressure adjustments to quickly change to varying production requirements. Not every application will require a strong blast sometimes a gentle breeze will accomplish the task. As an example one user of the EXAIR Super Air Knife employs it as an air curtain to prevent product contamination (strong blast) and another to dry different size parts (gentle breeze) coming down their conveyor. For Performance at different supply pressures see the chart below.
EXAIR products are highly engineered and are so efficient that they can be operated at lower pressures and still provide exceptional performance! This save’s you money considering compressed air on the average cost’s .25 cents per 1000 SCFM.
If you’d like to discuss altering the performance of your Super Air Knife, give us a call.
If you’re a regular reader of the EXAIR blog, you’re likely familiar with our:
This guideline is as comprehensive as you want it to be. It’s been applied, in small & large facilities, as the framework for a formal set of procedures, followed in order, with the goal of large scale reductions in the costs associated with the operation of compressed air systems…and it works like a charm. Others have “stepped” in and out, knowing already where some of their larger problems were – if you can actually hear or see evidence of leaks, your first step doesn’t necessarily have to be the installation of a Digital Flowmeter.
Here are some ways you may be able to “step” in and out to realize opportunities for savings on your use of compressed air:
Power: I’m not saying you need to run out & buy a new compressor, but if yours is
aging, requires more frequent maintenance, doesn’t have any particular energy efficiency ratings, etc…you might need to run out & buy a new compressor. Or at least consult with a reputable air compressor dealer about power consumption. You might not need to replace the whole compressor system if it can be retrofitted with more efficient controls.
Pressure: Not every use of your compressed air requires full header pressure. In fact, sometimes it’s downright detrimental for the pressure to be too high. Depending on the layout of your compressed air supply lines, your header pressure may be set a little higher than the load with the highest required pressure, and that’s OK. If it’s significantly higher, intermediate storage (like EXAIR’s Model 9500-60 Receiver Tank, shown on the right) may be worth looking into. Keep in mind, every 2psi increase in your header pressure means a 1% increase (approximately) in electric cost for your compressor operation. Higher than needed pressures also increase wear and tear on pneumatic tools, and increase the chances of leaks developing.
Consumption: Much like newer technologies in compressor design contribute to higher efficiency & lower electric power consumption, engineered compressed air products will use much less air than other methods. A 1/4″ copper tube is more than capable of blowing chips & debris away from a machine tool chuck, but it’s going to use as much as 33 SCFM. A Model 1100 Super Air Nozzle (shown on the right) can do the same job and use only 14 SCFM. This one was installed directly on to the end of the copper tube, quickly and easily, with a compression fitting.
Leaks: These are part of your consumption, whether you like it or not. And you shouldn’t like it, because they’re not doing anything for you, AND they’re costing you money. Fix all the leaks you can…and you can fix them all. Our Model 9061 Ultrasonic Leak Detector (right) can be critical to your efforts in finding these leaks, wherever they may be.
Pressure, part 2: Not every use of your compressed air requires full header pressure (seems I’ve heard that before?) Controlling the pressure required for individual applications, at the point of use, keeps your header pressure where it needs to be. All EXAIR Intelligent Compressed Air Product Kits come with a Pressure Regulator (like the one shown on the right) for this exact purpose.
Imagine you’re enjoying a nice shower. A cascade of warm water is soothing your body – and spirit – then, someone starts the dishwasher. Or a load of laundry. Or flushes the toilet. Suddenly, the “soothe” turns to “scald” or “freeze,” depending on whether you’ve been robbed of hot, or cold water. So, what happened?
What happened is, all of those “loads” on your house’s water supply that can ruin your shower experience are controlled by simple on/off valves…they open to permit a certain amount of water FLOW to pass. When the dishwasher starts, or someone decides to wash a load of whites, the HOT water from your nice warm shower is diverted, leaving a stream of cold water. When a toilet flushes, or it’s a load of colors, the COLD water is diverted…and that’s not just unpleasant, but downright painful. Either way, (in my house anyway,) a teenager is getting read the riot act.
The same phenomenon can apply in a compressed air system, if simple flow control valves are used to throttle the appropriate supply of air to a pneumatic device. If someone, for example, hooks up an air gun to blow off their tools or parts, the valves on EVERYTHING else will need to be opened up some to keep those devices working the same. In the case of an air gun like this, it usually happens too quick to make the necessary adjustments (by hand) and you’re probably left with a machine tripped off-line, or a ruined part.
Pressure Regulators can prevent this by keeping (or regulating) their downstream pressure to a set value. If a load elsewhere in the system is activated, the Pressure Regulator opens up, automatically, to keep its output constant. When that load is secured, the Pressure Regulator closes back down accordingly. Either way, no single load affects the operation of any others.
That’s only half the value of the use of Pressure Regulators, though. The other half is, well…the value. Just looking at a typical function of many EXAIR Intelligent Compressed Air Products – blow off – they’ll all pretty much accomplish the task if you run them, unrestricted, straight off your header. That’ll give you a good, strong blast of air flow…and it may be more than what’s required, and a waste of good air. Pressure Regulators will prevent this by allowing you to “dial in” the supply pressure to whatever it takes to get the job done, and no more.
Compressed air isn’t free. Heck, it isn’t even cheap. Don’t use any more than you have to, and get the most out of what you do use. Pressure Regulators are one important step in doing this. If you’d like to talk about optimizing your use of your compressed air system, give me a call.
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To understand the value of a having a Pressure Regulator at every point of use we should start with identifying the two types of Pressure Regulators, Direct Acting & Pilot Operated. Direct Acting are the least expensive and most common (as shown above), however they may provide less control over the outlet pressure, especially if they are not sized properly. However when sized properly they do an outstanding job. Pilot Operated Regulators incorporate a smaller auxiliary regulator to supply the required system pressure to a large diaphragm located on the main valve that in turn regulates the pressure. The Pilot Operated Regulators are more accurate and more expensive making them less attractive to purchase. The focus of this Blog will be on the Direct Acting Pressure Regulator.
The Direct Acting Pressure Regulator is designed to maintain a constant and steady air pressure downstream to ensure whatever device is attached to it is operated at the minimum pressure required to achieve efficient operation. If the end use is operated without a regulator or at a higher pressure than required, it result’s in increased air demand and energy use. To clarify this point, if you operate your compressed air system at 102 PSI it will cost you 1% more in electric costs than if the system was set to run at 100 PSI! Also noteworthy is that unregulated air demands consume about 1% more flow for every PSI of additional pressure. Higher pressure levels can also increase equipment wear which results in higher maintenance costs and shorter equipment life.
Sizing of the Air Regulator is crucial, if it is too small to deliver the air volume required by the point of use it can cause a pressure drop in that line which is called “droop”. Droop is defined as “the drop in pressure at the outlet of a pressure regulator, when a demand for compressed air occurs”. One commonly used practice is to slightly oversize the pressure regulator to minimize droop. Fortunately we at EXAIR specify the correct sized Air Regulator required to operate our devices so you will not experience the dreaded “droop”!
Another advantage to having a Pressure Regulator at every point of use is the flexibilty of making pressure adjustments to quickly change to varying production requirements. Not every application will require a strong blast sometimes a gentle breeze will accomplish the task. As an example one user of the EXAIR Super Air Knife employs it as an air curtain to prevent product contamination (strong blast) and another to dry different size parts (gentle breeze) coming down their conveyor.
EXAIR products are highly engineered and are so efficient that they can be operated at lower pressures and still provide exceptional performance! This save’s you money considering compressed air on the average cost’s .25 cents per 1000 SCFM.
Compressed air regulators are a pressure reducing valve that are used to maintain a proper downstream pressure for pneumatic systems. There are a variety of styles but the concept is very similar; “maintain a downstream pressure regardless of the variations in flow”. Regulators are very important in protecting downstream pneumatic systems as well as a useful tool in saving compressed air in blow-off applications.
The basic design of a regulator includes a diaphragm, a stem, a poppet valve, an orifice, compression springs and an adjusting screw. I will break down the function of each item as follows:
Diaphragm – it separates the internal air pressure from the ambient pressure. They are typically made of a rubber material so that it can stretch and deflect. They come in two different styles, relieving and non-relieving. Relieving style has a small hole in the diaphragm to allow the downstream pressure to escape to atmosphere when you need to decrease the output pressure. The non-relieving style does not allow this, and they are mainly used for gases that are expensive or dangerous.
Stem – It connects the poppet valve to the diaphragm. This is the “linkage” to move the poppet valve to allow compressed air to pass. As the diaphragm flexes up and down, the stem will close and open the poppet valve.
Poppet valve – it is used to block the orifice inside the regulator. It has a sealing surface to stop the flowing of compressed air during zero-flow conditions. The poppet valve is assisted by a spring to help “squeeze” the seal against the orifice face.
Orifice – it is an opening that determines the maximum amount of air flow that can be supplied by the regulator. The bigger the orifice, the more air that can pass and be supplied to downstream equipment.
Compression springs – they create the forces to balance between zero pressure to maximum downstream pressure. One spring is below the poppet valve to keep it closed and sealed. The other spring sits on top of the diaphragm and is called the adjusting spring. This spring is much larger than the poppet valve spring, and it is the main component to determine the downstream pressure ranges. The higher the spring force, the higher the downstream pressure.
Adjusting screw – it is the mechanism that “squeezes” the adjusting spring. To increase downstream pressure, the adjusting screw decreases the overall length of the adjusting spring. The compression force increases, allowing for the poppet valve to stay open for a higher pressure. It works in the opposite direction to decrease the downstream pressure.
With the above items working together, the regulator is designed to keep the downstream pressure at a constant rate. This constant rate is maintained during zero flow to max flow demands. But, it does have some inefficiencies. One of those issues is called “droop”. Droop is the amount of loss in downstream pressure when air starts flowing through a regulator. At steady state (the downstream system is not requiring any air flow), the regulator will produce the adjusted pressure (If you have a gage on the regulator, it will show you the downstream pressure). Once the regulator starts flowing, the downstream pressure will fall. The amount that it falls is dependent on the size of the orifice inside the regulator and the stem diameter. Charts are created to show the amount of droop at different set pressures and flow ranges (reference chart below). This is very important in sizing the correct regulator. If the regulator is too small, it will affect the performance of the pneumatic system.
The basic ideology on how a regulator works can be explained by the forces created by the springs and the downstream air pressures. The downstream air pressure is acting against the surface area of the diaphragm creating a force. (Force is pressure times area). The adjusting spring force is working against the diaphragm and the spring force under the poppet valve. A simple balanced force equation can be written as:
Fa ≡ Fp + (P2 * SA)
Fa – Adjusting Spring Force
Fp – Poppet Valve Spring Force
P2 – Downstream pressure
SA – Surface Area of diaphragm
If we look at the forces as a vector, the left side of the Equation 1 will indicate a positive force vector. This indicates that the poppet valve is open and compressed air is allowed to pass through the regulator. The right side of Equation 1 will show a negative vector. With a negative force vector, the poppet valve is closed, and the compressed air is unable to pass through the regulator (zero flow).
Let’s start at an initial condition where the force of the adjusting spring is at zero (the adjusting screw is not compressing the spring), the downstream pressure will be zero. Then the equation above will show a value of only Fp. This is a negative force vector and the poppet valve is closed. To increase the downstream pressure, the adjusting screw is turned to compress the adjusting spring. The additional spring force pushes down on the diaphragm. The diaphragm will deflect to push the stem and open the poppet valve. This will allow the compressed air to flow through the regulator. The equation will show a positive force vector: Fa > Fp + (P2 * SA). As the pressure downstream builds, the force under the diaphragm will build, counteracting the force of the adjusting spring. The diaphragm will start to close the poppet valve. When a pneumatic system calls for compressed air, the downstream pressure will begin to drop. The adjusting spring force will become dominant, and it will push the diaphragm again into a positive force vector. The poppet valve will open, allowing the air to flow to the pneumatic device. If we want to decrease the downstream air pressure, the adjusting screw is turned to reduce the adjusting spring force. This now becomes a negative force vector; Fa < Fp + (P2 * SA). The diaphragm will deflect in the opposite direction. This is important for relieving style diaphragms. This deflection will open a small hole in the diaphragm to allow the downstream air pressure to escape until it reaches an equal force vector, Fa = Fp + (P2 * SA). As the pneumatic system operates, the components of the regulator work together to open and close the poppet valve to supply pressurized air downstream.
Compressed air is expensive to make; and for a system that is unregulated, the inefficiencies are much greater, wasting money in your company. For blow-off applications, you can over-use the amount of compressed air required to “do the job”. EXAIR offers a line of regulators to control the amount of compressed air to our products. EXAIR is a leader in manufacturing very efficient products for compressed air use, but in conjunction with a regulator, you will be able to save even more money. Also, to make it easy for you to purchase, EXAIR offer kits with our products which will include a regulator. The regulators are already properly sized to provide the correct amount of compressed air with very little droop. If you need help in finding the correct kit for your blow-off application, an Application Engineer at EXAIR will be able to help you.
EXAIR offers 5 different styles of Safety Air Guns; Precision, VariBlast, Soft Grip, Heavy Duty and Super Blast. You can read more about the different styles of Safety Air Guns from a previous EXAIR blog “Not All Compressed Air Guns Are The Same” written by Justin Nichol. I will be targeting the accessories that can enhance the features of the EXAIR Safety Air Guns. These additions will make the Safety Air Guns more dynamic without sacrificing safety, efficiency, or durability.
OSHA 1910.242(b) requires chip guarding when compressed air is used for cleaning. EXAIR offers Chip Shields with our Safety Air Guns to meet this requirement. They are made from a polycarbonate disc which is practically unbreakable and protects the operator from any blow back of metal shavings or coolant. They come with a durable rubber grommet that squeezes onto the extensions and can be adjusted to maximize protection. We offer Chip Shields for the Precision, VariBlast, Soft Grip, and Heavy Duty Safety Air Guns with or without aluminum extensions.
For those far away targets and hard-to-reach areas, EXAIR offers aluminum extension pipes to attach to the Safety Air Guns. They can range from 6” (15 cm) to 72” (183 cm) in length. This light-weight and durable material allows for easy handling to reach high above your head or to span across unsafe areas. With the EXAIR air nozzles at the end, the blowing force is not sacrificed as the back pressure will generate a high velocity air stream. The aluminum extensions are offered with the Variblast, Soft Grip, and Heavy Duty Safety Air Guns. The Super Blast Safety Air Guns has the option for two different lengths of extensions, 3 feet (91cm) and 6 feet (183 cm).
In certain situations, you may need a way to blow air around a corner or in a tight space. The Stay Set Hose gives you that possibility of manually adjusting or re-adjusting the nozzles to target the correct areas. The hose has a “memory” function, and it will not creep or droop until you physically move it again. They come in lengths from 6” (15cm) to 36” (91cm), and they are offered with the Soft Grip and the Heavy Duty Safety Air Guns.
To get the proper amount of compressed air from the piping system to the Safety Air Guns, EXAIR offers a series of Coiled Hoses. They are made of a durable abrasion-resistant nylon material that is 12 feet long (3.6 meters). They have swivel fittings to allow for easy uncoiling, and a spring strain relief to keep the hose from kinking at the ends. The coiled design makes it easy to reach around the work area and retract back to the substation. This will help to keep the hose off the ground where potential dangers could occur. We offer 3 different connection sizes of 1/8” NPT, ¼” NPT, and 3/8” NPT. They can be used with our Precision, VariBlast, Soft Grip, and Heavy Duty Safety Air Guns. With the proper size, the Coiled Hoses can connect easily to the Safety Air Guns and supply the required amount of air with a minimal amount of pressure drop.
To improve the use of the Safety Air Guns, EXAIR offers a series of filters and regulators. The filters will remove dirty particles and liquid water from the compressed air that can affect the performance of the Safety Air Gun as well as contaminate the surface that you are cleaning. The regulators can control the amount of air pressure used for the Safety Air Gun; making them even more efficient. The idea for compressed air savings is to use the least amount of compressed air to do the job. If you only need 40 PSIG (2.8 Bar) to blow off an area, then you can save almost 40% of your compressed air as compared to doing that same job at 80 PSIG (5.5 Bar). The combination of a filter and regulator will allow you to control the proper amount of clean dry air to be used.
All of our Safety Air Guns are fitted with our engineered Air Nozzles which make them OSHA compliant for noise and dead-end pressure. With the accessories, you can optimize the use of the Safety Air Guns to better fit your application. If you need help in determine the correct Safety Air Guns and accessory items, you can contact an Application Engineer for help. If you are within the U.S. or Canada, you can take advantage of our 30-day unconditional guarantee to trial any of our stocked Safety Air Guns.
The Super Air Amplifier is a powerful, efficient, and quiet air mover. Applications currently in place include blowoff, drying, cooling, circulation and ventilation. Sizes from 3/4″ to 8″ are available to best match the air volume that is necessary to achieve the process goals. There are a couple of ways to change the performance of the Super Air Amplifier if either a small or large change to the output flow is required.
The chart below shows the Total Output Flow for each of the 6 models. As an example, the Model 120021 or 121021, when operated at 60 PSIG of compressed air supply, will have a total output flow of 120 SCFM. These same devices when operated at 80 PSIG will have a total flow of 146 SCFM. By simply using a pressure regulation device on the compressed air supply, the output performance can be tuned to match the desired outcome.
For those applications where much greater flow and/or force is needed, the option of installing a thicker shim is available. The Super Air Amplifiers are supplied with a 0.003″ shim installed (the 8″ model 120028, has a 0.009″ shim as standard) and can be fitted with shims of thicknesses of 0.006″ or 0.009″ (the 8″ model has an optional 0.015″ shim.) Installation of a thicker shim increases the slotted air gap, allowing for a greater amount of controlled air flow. As a general rule, doubling the shim thickness will double the air flow rates.
The Super Air Amplifier design provides for a constant, high velocity outlet flow across the entire cross sectional area,. The balanced outlet flow minimizes wind shear to produce sound levels that are typically three times quieter than other air movers. By regulating the compressed air supply pressure and use of the optional shims, adjustability and flexibility of the unit is wide ranging and sure to meet your process needs.
If you have questions regarding the Super Air Amplifier, or would like to talk about any EXAIR Intelligent Compressed Air® Product, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.