What is the Super Air Knife?
The Super Air Knife is the latest generation of air knife that dramatically reduces compressed air usage and noise when compared to other blowoffs. The Super Air Knife offers a more efficient way to clean, dry or cool parts, webs or conveyors. It delivers a uniform sheet of laminar airflow across the entire length with hard-hitting force.
Noisy blowoffs become a whisper when replaced with the compact Super Air Knife. Even at high pressures of 80 PSIG (5.5 BAR), the sound level is surprisingly quiet at 69 dBA for most applications! Amplification ratios (entrained air to compressed air) of 40:1 are produced. The Super Air Knife meets OSHA dead-ended pressure and noise requirements.
How the Super Air Knife works
Compressed air flows through an inlet (1) into the plenum chamber of the Super Air Knife. The flow is directed to a precise, slotted orifice. As the primary airflow exits the thin slotted nozzle (2), it follows a flat surface that directs the airflow in a perfectly straight line. This creates a uniform sheet of air across the entire length of the Super Air Knife. Velocity loss is minimized and force is maximized as the room air (3) is entrained into the primary airstream at a ratio of 40:1. The result is a well defined sheet of laminar airflow with hard-hitting force and minimal wind shear.
Applications
Part drying after wash
Sheet cleaning in strip mills
Conveyor cleaning
Part or component cooling
Web drying or cleaning
Environmental separation
Pre-paint blowoff
Bag opening/filling operations
Scrap removal on converting operations
Dry
Blowoff
Cool
PVDF (Polyvinylidene Fluoride) Super Air Knife
Super Air Knives in PVDF (Polyvinylidene Fluoride) offers superior strength and are resistant to UV-light, inorganic chemicals, solvents, ozone, weather, fungi, chlorinated hydrocarbons, highly corrosive acids, weak bases and salts. The PVDF Super Air Knife uses PTFE Shims, Type 316 Stainless Steel pipe plugs, and Hastelloy c-276 alloy screws to withstand harsh environments. The PVDF Super Air Knife is suitable for manufacturing processes that involve electroplating, solar cells, lithium ion batteries, transfer of acids and caustic chemicals, brine, solvent recovery, semiconductors, and medical devices. It can withstand temperatures up to 275oF (135oC).
Advantages
Quiet – 69 dBA for most applications
Minimal air consumption
40:1 air amplification
Uniform airflow across entire length
Easy mounting – using Universal Air Knife Mounting System or compressed air inlets on each end and bottom
Compact, rugged, easy to install
Recessed hardware
No moving parts – maintenance free
Variable force and flow
Stainless steel screws in all models
Special lengths available
Unlimited system lengths of uninterrupted airflow available
Stock lengths to 108 ” (2743mm) in aluminum, 303 stainless steel, and 316 stainless steel (ss – for temperatures up to 800°F (427°C), food processing or corrosive environments), and PVDF up to 54″ (1372mm) for superior corrosion resistance.
A Model 110024SS 24″ (610mm) Stainless Steel Super Air Knife dries bolt covers exiting an electro-polishing tank.
Blowoff Comparison
Blowoff Comparison
There are a variety of ways to blow the water from the bottles shown in the photo, but which method is best? The following comparison of drilled pipe, flat air nozzles, a blower and the Super Air Knife proves that EXAIR has the best choice for your blowoff, cooling or drying application.
Our goal for each of the blowoff choices was to use the least amount of air possible to get the job done (lowest energy and noise level). Compressed air pressure required for each was 60 PSIG (4.1 BAR) which provided adequate velocity to blow the water off. The table below summarizes the overall performance. Since your actual part may have an odd configuration, holes or sharp edges, we took sound level measurements in free air (no impinging surface).
Compare these Blowoffs
Drilled Pipe
This common blowoff is very inexpensive and easy to make. For this test, we used (2) drilled pipes, each with (25) 1/16″ (1.6mm) diameter holes on 1/2″ (13mm) centers. As shown in the test results below, the drilled pipe performed poorly. The initial cost of the drilled pipe is overshadowed by its high energy use. The holes are easily blocked and the noise level is excessive – both of which violate OSHA requirements. Velocity across the entire length was very inconsistent with spikes of air and numerous dead spots.
Flat Air Nozzles
As shown below, this inexpensive air nozzle was the worst performer. It is available in plastic, aluminum and stainless steel from several manufacturers. The flat air nozzle provides some entrainment, but suffers from many of the same problems as the drilled pipe. Operating cost and noise level are both high. Some manufacturers offer flat air nozzles where the holes can be blocked – an OSHA violation. Velocity was inconsistent with spikes of air.
Blower Air Knife
The blower proved to be an expensive, noisy option. As noted below, the purchase price is high. Operating cost was considerably lower than the drilled pipe and flat air nozzle, but was comparable to EXAIR’s Super Air Knife. The large blower with its two 3″ (76mm) diameter hoses requires significant mounting space compared to the others. Noise level was high at 90 dBA. There was no option for cycling it on and off to conserve energy like the other blowoffs. Costly bearing and filter maintenance along with downtime were also negative factors.
EXAIR Super Air Knife
The Super Air Knife did an exceptional job of removing the moisture on one pass due to the uniformity of the laminar airflow. The sound level was extremely low. For this application, energy use was slightly higher than the blower but can be less than the blower if cycling on and off is possible. Safe operation is not an issue since the Super Air Knife cannot be dead-ended. Maintenance costs are low since there are no moving parts to wear out.
The target for each blow-off device was to consume the least amount of air possible to perform the task (at the lowest energy and noise levels). The required air pressure for each device was 4.1 bar inlet pressure, (60 PSIG), at which an adequate speed was provided to blow the water off. The table below summarizes the general performance. Since the workpiece you are actually about to blow off may have an irregular structure, holes or sharp edges, the noise level measurements were made in free air (without hitting a surface).
Blowoff Comparison Statistics
Type of Blowoff 24″
PSIG
BAR
SLPM
Horse Power Required
Sound level dBA
Purchase Price
*Annual Electrical Cost
Approx. Annual Maint. Cost
First Year Cost
Drilled Pipe
60
4,1
4.924
26,10
91
45 €
4.669 €
840 €
5.509 €
Flat Air Nozzles
60
4,1
7.273
38,03
102
190 €
6.803 €
1.320 €
8.123 €
Blower Air Knife
3
0,2
N/A
7,46
90
5.000 €
1.334 €
1.370 €
2.704 €
Super Air Knife
60
4,1
1.557
8,20
69
559 €
1.467 €
280 €
1.747 €
*Based on national average electricity cost of 8.6 cents per kWh or 3 cents per standard cubic metre. Annual cost reflects 40 hours per week, 52 weeks per year.
Performance
Airflow field
Super Air Knife Performance with .002″ (.05mm) thick shim installed, tested with Super Air Knife 110012 (30cm long)
