Blower Air Knife Systems: Fast Facts

What is an Air Knife? An air knife is a slotted air manifold used to discharge a high-velocity curtain of air for drying or cleaning conveyorized product.

What is a Blower Air Knife System? An air knife system consists of a blower, air knives, and accessories to connect the blower to the air knives (flex hose, clamps, dividers, etc.)

Common Air Knife System Applications:
Metal Finishing Lines - powder coating pretreatment drying and other applications.	Food and Beverage Packaging - bottles, cans, pouches, and other packages must be dried prior to packaging.	Parts Washing / Drying - removal of cleaning solutions and/or water after washing stations.	Continuous Strip / Web Material - removal of water from materials such as plastics or wire mesh.

Save on Compressed Air Energy Costs
by Switching to a Blower Air Knife System

Blower Air Knife Systems are becoming the industry standard tool for applications such as blow-off, drying, and cleaning in industrial facilities. The primary reason is energy cost. The cost of running a compressed air blow-off system on a single conveyor line can easily reach $100,000 per year in electricity alone, depending on factors such as the quantity and size of nozzles used, hours of operation, and local energy cost. In a typical application, a well designed blower air knife system can replace a compressed air blow-off system using only 10-20% of the energy. This means that a plant using $100,000 worth of compressed air to dry parts on a conveyor line has the opportunity to save $90,000 per year by switching to a blower air knife system. This is not an exaggeration but a typical scenario that is seen on a daily basis by those in involved in the business of plant air audits and related fields.

Sounds too good to be true? You are probably asking the question: How can it be possible for a blower air knife system to replace my compressed air equipment at only 10% of the energy cost? One of the reasons is that a large portion of the energy used by your compressed air system is actually being wasted. You may think that your air knives or drilled pipe are putting out 100 psi of compressed air, but this is not true; due to the pressure losses that occur throughout your piping system, your pressure is much lower than 100 psi by the time the air travels from your compressor to your blow-off station. You are paying for 100 psi but you are not getting 100 psi - hence the wasted money. A blower air knife system clearly has the advantage here because the blower can be installed at the point of use - the air does not have to be piped across the plant to to get to the air knives, thus the pressure drop is much lower than what you see with compressed air.

Another reason is the difference in pressure and volume: Compressed air provides high pressure, low volume air, while a blower provides low-pressure, high volume air. Since volume is much cheaper than pressure, a blower air knife system has the advantage. You do not need any more than 3-4 psi from an air knife system to dry or clean parts. In fact, most air knife system applications require only 2.5 psi or less for effective performance. It should be common sense that, if you are using any more pressure than you need, you are wasting money. Low-pressure, high-volume air is a much more effective and much more efficient way to perform drying and cleaning. Vortron's blowers and air knives have been designed specifically for drying and cleaning, and have been sized to provide the optimum amount of pressure and volume for these applications. A 100 psi air compressor was never seriously intended to blow through wide open copper pipe onto a conveyor line; this is only done because it is assumed to be cheap, although a plant air audit will clearly show that this is incorrect.

Vortron's master distributors have extensive experience providing complete plant air audits to end users in many different areas of manufacturing, and are available to do the same for you. They will perform a complete analysis of your plant air system and provide a report informing you of any and all inefficiencies that exist and how to fix them. They will analyze the performance of any compressed air blow-off and/or air knife systems that you may be using, and show you where you have the opportunity to save energy and exactly how much you can save. If your distributor is not able to perform the audit themselves, they will refer you to a local distributor within their network who will be happy to perform the service. You will receive reliable and unbiased information from a distributor who has had extensive experience with both compressed air and blower air knife systems.

How Does a Blower Air Knife System Work?

A Blower Air-Knife System is still a relatively new type of machinery to most individuals in plant engineering and maintenance today. Air Knives have become commonplace only within the last 15 years as an alternative to the costly process of using compressed air for applications such as drying, blow-off, debris removal and others. In addition to energy savings, the effectiveness of an optimized air knife system is the second reason why air knives are now becoming more widely used. How is a blower air knife system able to perform effectively in applications where compressed air and other solutions have failed?

The key to effective drying and debris removal is to have enough velocity and airflow (volume). In order for air knives to function properly, they must be sized, along with a blower, with these two important parameters in mind. A compressed air blow-off system will usually provide insufficient volume for adequate drying. A plant air compressor is capable of producing high-velocity air, but due to the extraordinarily small gap size (often less than 0.005") of most air knives that are designed for use with compressed air, there is not sufficient volume to sustain the velocity all the way to the surface of the product being dried. At the other extreme, fan-type blowers that produce less than 20"H20 pressure are often mistakenly used in air knife applications, often with "home-made" air knives or slotted PVC pipe. This type of blower is capable of producing a high volume of airflow, but insufficient pressure and velocity, thus the air curtain from the air knives is not powerful enough to force water or other debris away from the surface of a product.

Air velocity for a Vortron blower air knife system can range from 25,000 to 40,000 ft/min, which equates to approximately 1.5 to 4 psi and 40 to 110" H20. Our experice has shown that the optimum range of velocity and pressure for the majority of air knife applications (mostly water removal) lies in the range of 30,000 to 35,000 ft/min. Higher velocity is required for more difficult material, such as metal shavings and oil, while lower velocity is required for removal of lighter material such as dust. Each Vortron air knife system is designed with great care to ensure that not only is the proper amount of velocity produced, but also that there is sufficient volume to sustain the velocity from the air knives to the surface of your product.

Vortron does this by selecting the following: (1) an air knife gap size that will allow for sufficient airflow, typically 0.045", or greater if the air knives will be placed at a considerable distance from the surface of your product; (2) an air knife length (and quantity of air knives) that will cover the necessary surfaces and force debris away from the product; (3) an Air Power® centrifugal blower configured at the appropriate speed (RPM) to produce the desired pressure when used in conjunction with the particular air knife system.

Air Knife Dimensions and Inlet Orientations

Gap Size: Standard air knife gaps: 0.035", 0.045" - Custom sizes from 0.020" to 0.070" are possible.

Finish: Both stainless steel and aluminum air knives are polished.

Air Knife Inlet Length: Standard length is 8" - Optional lengths up to 18".

Dimensions
Model
Inlet OD	1.5"	2.0"	2.0"	3.0"
Manifold OD	2.5"	3.0"	3.5"	5.5"
Height	3.5"	5.75"	6.0"	10.0"
Length	Up to 30"	Up to 60"	Up to 60"	Up to 154"
Material	Stainless Steel	Aluminum	Stainless Steel	Stainless Steel
Air-Knife Measurements: This illustration the manifold OD and height measurements for an aluminum extruded air knife. For the diamond air knife models, the manifold OD is the upper-right side (as shown above); the height is the lower-right side. The Micro-Body air knife manifold OD is the top of the triangle, and the height is measured along the right side, or the extended edge of the air knife. For all air knife models, the length is considered to be the effective length, not including the inlets.

Available Inlet Orientations
Right Hand	Vertical Middle	90° Option
Left Hand	Dual, Vertical Middle	45° Option
Dual	Dual, Vertical Middle	Dual, Dual Vertical