Super Air Knife Cools Laminated Packaging Material

I recently worked with one of our distributors on a Super Air Knife application for a manufacturer of flexible packaging material. They create the plastic material that is commonly wrapped around the outside of a wide variety of different containers. The material exits the laminating machine at about 129°F (54°C) and must be cooled to close to room temperature before it is able to be rolled without the material sticking together.

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Model 110012, positioned to maximize counter-flow

They performed a test with a Model 110012, recording the temperature after the knife and determined that it would be suitable for them. Prior to using the Super Air Knife, they had been using a series of fans to cool down the material. This worked to some degree, but they had been experiencing quality issues as a result of inadequate levels of cooling and were forced to slow down the laminating machine in order to compensate. By implementing the Super Air Knife, they were able to cool the material down to ambient temperatures without having to slow production. As an added measure, they ordered a second knife to install on the underside to further decrease the temperature of the material.

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Graph showing the effectiveness of a Super Air Knife vs. fans or no cooling method.

The laminar airflow of the Super Air Knife is critical to the success of any cooling application. A fan “slaps” the air which provides random spikes of air at moderate velocities. The uniform, high velocity, laminar sheet of air from the Super Air Knife, in addition to the low compressed air consumption, makes it a much more effective cooling method than fans. The design of the Super Air Knife allows it to entrain ambient air at a rate of 40:1, maximizing the force and flow from the knife while keeping compressed air usage to a minimum.

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The design of the Super Air Knife allows it to entrain air from the top and bottom, creating a 40:1 air amplification ratio.

Super Air Knives are available in a range of different materials and sizes. From stock EXAIR carries knives from 3”-108” in Aluminum, 303 Stainless Steel, 316 Stainless Steel, and 3”-54” in PVDF (Polyvinylidene Fluoride) for superior resistance to highly corrosive materials. In addition to being an excellent tool for cooling, the Super Air Knife can solve a wide range of drying and blowoff applications. If you have an application that would be better served with one of EXAIR’s Super Air Knives, reach out to us today and get yours on order! We ship same day from stock with orders received by 3:00 pm EST, stop wasting time with ineffective cooling or blowoff methods!

Tyler Daniel
Application Engineer
E-mail: TylerDaniel@exair.com
Twitter: @EXAIR_TD

Not a Fan of Fans Because Rising Air Temp Will Kill Your Electronics

Using a fan is a popular method for machine builders to provide cooling for an electrical enclosure.  The electrical panel stays cool for machine acceptance at the factory, and possibly for even the first 6-8 months of operation and then one day, there is a problem, and the machine shuts down due to an over heated component within the panel. This leads to opening up the panel, possibly placing an external fan, and operation of the machine in an unsafe condition, to meet the daily production needs.  What has led to this situation?  Summertime!

To better understand the situation, let’s review the heat formula.  The total heat content of air consists of the sensible and latent heat factors. Latent heat is the heat that is required to change the state of a material, say from liquid to solid.  Water to ice is an easy way to understand this type of heat.  When heat is removed from water at 32°F it turns to ice at 32°F.  There is no temperature change, but heat has been removed. Sensible heat is dry heat, it is a result in change of temperature, but not change in state or moisture.  For fan cooling, the air and moisture only change temperature and not state, we can focus on the sensible heat portion.

In English units:  Q = Cp x ρ x q x ΔT x 60 min/hr

And for air:

Q –  is the sensible heat flow in BTU/hr

Cp – is the specific heat in BTU/lb °F – 0.2388 BTU/lb °F

ρ – is the air density at standard conditions – 0.075 lb/ft3

q – is measured air flow in ft3/min – CFM

ΔT – is the temperature difference in °F – Final Air Temperature – Starting Air Temperature

Plugging in the constant values, gives us:

Q = 1.0746 x CFM x ΔT

It is common to chart the above formula for various ΔT values, plotting Q vs. CFM values on a dual logarithmic scale, as shown below-

BTU-CFMGraph4

As an example, for an internal heat load of 1300 BTU/hr, to ensure that the temperature rise (from ambient) in the cabinet does not exceed 20°F, 60.5 CFM of air flow is required (the red line above).  A fan with this CFM rating is specified and installed in the panel.

This works  when the ambient temperature is a comfortable 75°F, in a climate controlled factory, or the cooler months of the year.  The problem occurs when the ambient temperature increases to 95°, 100°, or even 105°F,  not uncommon in the summer, and in plants that create large amount of heat, like metal production, and near boiler systems and furnaces.  Under these conditions, the fan will still maintain the 20°F difference, but the internal temperature of the cabinet will rise to 115°-125°F, temperatures where electrical components start to fail or shut down.  The solution to this issue?  Lower the Starting Air Temperature.

The EXAIR Cabinet Cooler Systems use our Vortex Tube technology to take compressed air and provide a cold flow of air that enters the enclosure at 5o°F less than the compressed air temperature.  With a compressed air temperature of 70°F, common for industrial compressed air systems, the Cabinet Cooler will deliver cold air at 20°F.  Again using the chart above, flowing just 20 SCFM of this air will absorb the 1300 BTU/hr of heat (the green line), and result in an internal air temperature 80°F no matter the ambient air temperature.  The electronics in this enclosure will run trouble free, for a long time. This ambient air temperature problem is also true of air-to-air heat exchangers, as the ambient air temperature rises the ability to remove heat diminishes.

Another consideration, the fan system is bringing in air from the surroundings, which is hot and dirty, passing it through a filter (which gets clogged, reduces air flow, and needs to be replaced.) The Cabinet Cooler System, includes an automatic drain filter separator, which filters the compressed air to be free of dirt, dust and moisture. The air entering the enclosure is cool, dry and fee of dust and debris.

ETC CC
NEMA 4 Cabinet Cooler System with Optional Electronic Temperature Control

To discuss your application and how the EXAIR Cabinet Cooler System can be a benefit at your facility, feel free to contact EXAIR and myself or one of our other Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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Cabinet Cooler Keeps Large Panel Cool Near Steam Exhaust

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Stainless cabinet near steam vent

The photo above shows a stainless steel Cabinet at left which has been installed near to a steam exhaust (within 1 meter) in a beverage manufacturing plant.

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150 mm diameter fan, lower right side

 

Inside the panel is a 150 mm diameter fan which is pulling in an air and steam mixture which is causing the temperature inside the cabinet to climb to unacceptable levels. The result is that the motor drives located inside the panel are failing, causing a tremendous cost for replacement and downtime.

Our local distributor worked with the customer to acquire the necessary data for us to calculate heat load within the panel. We determined the customer needed our model HT4880SS-240 Cabinet Cooler System to keep their internal panel temperature at a more reasonable level, year round, even in their worst case scenario with constant steam exhaust in the area.

One key component to success in this application will be removal of the fan and covering of the vent that it once occupied in order to keep the steam from being drawn into the inside of the panel. Historically, fans have been the go to strategy for keeping panels like this cool. However, in this situation, as in many others, the fans pull in un-wanted contamination. There isn’t any filter that can keep steam from getting inside and causing all sorts of problems with condensate forming on internal components, thus promoting corrosion and heat related failures.

The Cabinet Cooler System will provide a filtered, and dry source of cooling airflow which will produce a slight positive purge pressure on the panel to keep such harmful outside atmospheres from entering into the panel. This assures, long life for the panel components and much less hassle and problems associated with heat related failures.

Neal Raker, International Sales Manager
nealraker@exair.com
EXAIR_NR