How does an Air Knife work?

The Supreme Air Products Air Knife Systems feature multiple ¼-20 mounting holes at the rear face for quick and easy installation. We also offer an optional air knife mount on a magnetic base which is equipped with an on/off switch. All Air Knife Systems come pre-installed with a 0.002” shim which is optimal for most applications, however additional shims can be installed for heavy duty wiping, cooling and drying as needed. Our Air Knife Systems are stocked in a variety of sizes. For custom sizes, multiple air knives can be joined together end-to-end and secured with an optional bracket. Since our air knife systems are full flow, joining 2 or more air knives together will produce one continuous air stream without interruption.

What Type of Air Knife do we carry?

The Supreme Air Products Air Knife Systems are offered in two models – regular and supreme. The Regular Air Knife is cost efficient and provides a 30:1 air amplification ratio with air consumption of 3.4 CFM per inch at 80 PSI. The Supreme Air Knife provides the most efficient performance with a 40:1 air amplification ratio and lower air consumption of 2.9 CFM per inch at the same pressure. The Supreme Air Knife also produces lower noise levels, making it the top choice among our clients.

	Supreme Air Knife	Regular Air Knife
Air consumption @80 PSIG	~2.9 SCFM per inch	~3.4 SCFM per inch
Air amplification ratio	40:1	30:1
Corrosion Rating	Excellent	Excellent
Material	Aluminum & Stainless Steel	Aluminum & Stainless Steel
Noise level	Low	Medium
Available Sizes	2″ (51mm) up to 54″ (1372 mm)	3″ (76mm) up to 54″ (1372 mm)
Custom size available	Yes	Yes
Temperature Rating	400°F (204°C)	275°F (135°C)

How does an Air Knife System Work?

1. Compressed air enters the air chamber through a ¼” NPT inlet located at the back or end ports of the air knife.
2. Surrounding air is entrained into the primary air stream due to the coanda effect. This produces an air amplification ratio of 40:1 in the supreme air knife and 30:1 in the regular air knife.
3. The air stream now exits the air knife system. In the supreme air knife, the air flows straight outward, whereas in the regular air knife, the air travels downward at a 90° angle along the front face of the air knife. In both cases, the amplified air stream resembles a hard-hitting curtain of air which reduces energy consumption in blow-off and cooling applications due to the air amplification effect.

Important Information

Regular and supreme air knife systems are available in aluminum or stainless-steel construction and provide quality laminar flow. While our competitors opt for plastic shims and metal screws, Supreme Air Products Corp. takes pride in the quality of its products and uses only stainless-steel shims and screws to ensure durability and longevity.

Air Knife Specifications

Size: We offer both Regular and Supreme Air Knives in aluminum and stainless-steel construction. The following 12 sizes are in stock and ready to ship: 3″ (76 mm), 6″ (152 mm), 8″ (203 mm), 9″ (229 mm), 12″ (305 mm), 18″ (457 mm), 24″ (610 mm), 30″ (762 mm), 36″ (914 mm), 42″ (1067 mm), 48″ (1219 mm), and 54″ (1372 mm). Custom sizes available upon request.

Material: Air Knife Unit: Aluminum or Stainless Steel Shims: Stainless Steel Screws: Stainless Steel

Mounting: Along the rear side of the Air Knifes there are multiple ¼”-20 mounting holes that allow for easy installation without disassembling the unit. We offer an optional Air Knife Mount that can be found in our “Accessories” section. Ridged compressed air pipe can also support your Air Knife!

Compressed Air Inlet(s) Supreme Air Knife incorporates air inlet(s) located at each end (excluding 3″/76mm models) and on the back to allow flexible air use, air inlet choice, and high flow to higher force jets.

Air Supply Filtration To achieve the best performance, it’s vital to use a clean and dry source of compressed air. We recommend using a Supreme Air Products 5-micron auto-drain filter, which is properly sized in order to avoid airflow restrictions.

SUPREME Air Knife Performance

with .002″ (.05mm) thick shim installed. 12″ (305mm) Supreme Air Knife tested.

REGULAR Air Knife

with .002″ (.05mm) thick shim installed. 12″ (305mm) Regular Air Knife tested.

Drilled Pipe Air Consumption: Chart *Compressed Air Flow in Standard Cubic Feet Per Minute (SCFM)

Drilled Pipe

Many of our clients don’t know this, but using a drilled pipe is one of the most expensive and ineffective way to utilize compressed air. As you can see in the above table chart performed in our tests, the drilled pipe performs poorly. Because of its hight compressed air use, drilled pipe cost is quickly overtaken and does not pay off. Besides that, OSHA noise level requirements are not fulfilled and holes located on the drilled pipe can quickly become blocked. Because of the nature of the drilled pipe, airflow that goes across the entire length of the drilled pipe unit is not uniformed and can result in many dead spots and big spikes of air.

Air Knife FAQs

1. If I install blower alongside Air Knife, will it operate?

No, because all our Air Knives are designed to use only compressed air. Besides that, blowers create heavy noise, they are robust and quite expensive with 3” – 6” connections. If used with Air Knife, they won’t be able to produce enough amount of force in order to operate.

2. In order to create a custom length for my needs, can I cut Air Knife?

No. Because our Air Knife is precision-machined, cutting them to the desired length by yourself is not allowed at all. By cutting it would completely expose the internal design of Air Knife with no possibility to reseal the Air Knife in its previous condition as it was manufactured. If you really need custom sizes, we can manufacture them for you.

3. Is it possible to get more force out of my Air Knife and how?

To achieve the higher force of airflow from Air Knife you need to increase the volume of that pass trough Air Knife. That is possible using two (2) ways:

1. increase the maximum safe level of supply pressure which is 250 PSIG
2. or install additional shims. You can order additional shims here.

4. What would be a recommended pressure that we should be used with the Air Knife inside our production line?

No matter in which type of applications our Air Knife will be installed, make sure you always try to use the lowest pressure. Using the pressure regulator is something we strongly suggest also in order to increase force (airflow) to the point where you think your application problem is rectified. You can achieve maximum pressure of 250 PSIG with our Air Knife.

5. How can I install Air Knife in my production line?

Because of stability, it is suggested to mount Air Knife on the rigid compressed air pipe. If something like this is not possible in your case, our Air Knife has multiple 1/4-20 mounting holes which are located on the back of the Air Knife.

6. Is it possible to order larger Air Knife then 54” which is the largest size you offer on sale?

Yes, it is possible. We are capable to produce Air Knife up to 109”, and in addition to that, we can custom machine any Air Knife length upon special requests.

7. Under which mac. and min. temperatures your Air Knife can operate?

Depending on material type, our Air Knife can withstand different temperatures.

Aluminum Air Knife:
275°F (135°C)

Stainless Steel (Type 303) Air Knife:
400°F (204°C)

Stainless Steel (Type 316) Air Knife:
800°F (427°C)

* Using temperatures above 800ºF (427ºC) could produce inter-granular corrosion which can damage Air Knife and eventually plug the air gap opening

8. Do I need to install more shims if there is no enough airflow coming out from Air Knife?

Before and foremost we want to note that it is very important to make sure Air Knife is performing properly before you decide to increase the standard gap opening of .002”. Many factors such as a clogged filter or undersized air compressor can cause low air flow coming from Air Knife. In order to make sure full line pressure is available, we advise you to install a pipe-tee that will go along with a pressure gauge at any available inlet located on Air Knife. If you see that full line pressure is present and no additional flow is required, you can turn off the compress air supply and disassemble your Air Knife. Before reassembling Air Knife back again with additional shim, make sure you clean all its parts such as air knife body, cap, and shim. We also want to note that you need to tighten each screw on the air knife to 7.5 ft/lbs.

9. What should I do if my Air Knife has dead spots?

In order to make sure all our customers are satisfied, we make sure that every Air Knife that comes out from our facility is properly tested in order to ensure it has proper flow characteristics. Below we will show you 3 (three) possibilities that could cause Air Knife dead spots:

1. Air Knife should be inspected for clogging or/and direct contamination. In case cleaning is necessary, we included instructions on how to clean our Air Knifes inside Installation and Maintenance manual that comes with every Air Knife once bought through our web store.
2. It is possible that screws located on Air Knife have been over tightened during installation or mounting. You should tighten screws on Air knife to 7.5 ft/lbs
3. Make sure you do not use undersized lines, filters or restrictive fittings that can lower the amount of airflow to enter into the Air Knife plenum chamber.

Air Knife Applications

Air Knife Dimensions

Supreme Air Knife Dimensions

Regular Air Knife Dimensions

Air Knife 3D CAD FILES

Our 3D CAD files for Air Knives are offered in 3 file formats available for download below.

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