Many Air Knife Materials and Shim Options to Suit Your Application

The EXAIR Super Air Knives are used in many applications ranging from part drying, to web cleaning, to conveyor blowoff, and many other uses. For most processes, the aluminum models provide the performance required and withstand the environmental conditions present.

Ambient temperature limits for the aluminum models is 180°F (82°C). EXAIR also offers the air knives in types 303 and 316 Stainless Steel, which increase the temperature limit to 800°F (427°C) and provides a great degree of corrosion resistance. For the harshest, most corrosive environments, an air knife constructed of Polyvinylidene Fluoride (PVDF) with a temperature limit to 275°F (135°C) is available.

Super Air Knives
Aluminum, Stainless Steel and PVDF Super Air Knives

But what can we do about those applications where the increased corrosion resistance isn’t needed and the temperatures do not approach anywhere near to 800°F (427°C)?

The solution to this situation is an aluminum air knife with a custom stainless steel shim. The aluminum material is rated to 400°F (204°C) and the shim is good to 800°F (427°C) so this knife can be used in those hotter environments up to 400°F (204°C). This option helps to keep the cost of the knife low, by utilizing the lower cost aluminum for the body and cap.

The table below details the materials of construction options for the Super Air Knife – a wide array of material offerings to suit even the hottest, harshest conditions.

Air Knife Temperature Table

We recommend consulting with an Application Engineer to review the application, process, and environmental conditions, and we can present best options.

And don’t forget, the shims can be further customized for special blowoff requirements. See the blog that my colleague, Russ Bowman, posted here.

If you have questions about Super Air Knives or any of the 15 different EXAIR Intelligent Compressed Air® Product lines, feel free to contact EXAIR and myself or any of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer
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Special Cabinet Cooler Options – High Temperature, Non-Hazardous Purge and Type 316 Stainless Steel

Recent blog discussions about the EXAIR Cabinet Cooler Systems have covered many topics including correctly sizing one, the NEMA ratings, and how-they-work.  In this blog I will review three special options that are available for the most extreme environmental conditions- high temperatures, dirty environments, and harsh or corrosive areas.

High Temperature – For enclosures that reside in high temperature ambient conditions such as near furnaces, boilers, or ovens, EXAIR offers a High Temp version, with special internal components designed to withstand the elevated temperatures.  Cabinets near sources of high heat certainly need to be kept cool, and the EXAIR High Temperature Cabinet Cooler is specially suited to for use in these locations.

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High Temperature Dual Cabinet Cooler System

Non-Hazardous Purge (NHP) – Cabinet Cooler Systems with this feature provide a continuous positive purge within the enclosure to prevent contaminants from entering through small holes or conduits.  Especially suited for dirty and dusty environments, the NHP Cabinet Cooler Systems provide a slight positive pressure inside the enclosure. This is done by passing 1 SCFM (28 SLPM) of air through the cooler when the the solenoid is in the closed position. When the thermostat reaches the set-point temperature and energizes the solenoid, the full line pressure of air is delivered to the Cabinet Cooler providing the full cooling capability, and still keeping the positive pressure.  When the internal temperature cools to the set-point, the solenoid closes and the system returns to the 1 SCFM (28 SLPM) of air flow condition.

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Non-Hazardous Purge Cabinet Cooler for Dirty, Dusty Environments

Type 316 Stainless Steel NEMA 4X Cabinet Coolers – For enclosures that are in food service, pharmaceutical, harsh, and/or corrosive environments, and any application where 316 stainless steel is preferred, the Cabinet Coolers are available in the Type 316 stainless material. The systems are UL Listed for wash down environments, ensuring the enclosure electrical contents remain cool and dry under any condition. Noted applications include on ocean going ships, power plants, medical device manufacturing facilities, and bakeries.

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Type 316 Stainless Steel NEMA 4X Cabinet Cooler System

Please note that the High Temperature, Non-Hazardous Purge and Type 316 Stainless Steel Cabinet Coolers are each available from stock!  No waiting for these special models.

To discuss your application and how a Cabinet Cooler System or any EXAIR Intelligent Compressed Air Product can improve your process, feel free to contact EXAIR, myself, or one of our other Application Engineers. We can help you determine the best solution!

Brian Bergmann
Application Engineer

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High Temperature Vortex Tube for Sensor Cooling

Last year I worked with a power company that was having issues with Position Feedback Sensors overheating causing erroneous readings and early failures.  The sensors were located above a steam turbine, and the ambient temperatures reached 128°F with spikes to 140-150°F.  The customer had called in looking for a way to keep the sensors cool, using minimal compressed air, and in a robust package.  After reviewing the details, we recommended the High Temperature Vortex Tube, model HT3210.  While using just 10 SCFM of 100 PSIG compressed air, the HT3210 provides 8 SCFM of cold air at a temperature drop of 54°F from the supply air temperature.  Bathing the sensor with this cool air keeps prevents it from heating up and has eliminated the bad readings and prevented the early failures.

The customer recently implemented the same fix for another set of sensors.

Plant Photo
Power Generation Process, with (3) Position Feedback Sensors
Sensor
Position Feedback Sensor

The High Temperature Vortex Tube is a special Vortex Tube offering from EXAIR that utilizes a brass generator and hi-temp seal for use in ambient temperatures up to 200°F.  Simply supply clean, dry compressed air, and get cold air starting at 50-54°F lower than the supply air temperature.  With sizes ranging from 2 to 150 SCFM, there is a Vortex Tube that will meet most applications.

Vortex tube
High Temperature Vortex Tube

If you have questions about the Vortex Tubes, or would like to talk about any of the EXAIR Intelligent Compressed Air® Products, feel free to contact EXAIR and myself or one of our Application Engineers can help you determine the best solution.

Brian Bergmann
Application Engineer

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Cooling An Overheating Pneumatic Positioner

Pneumatic positioner

What can you do when the pneumatic positioner in your high temperature application is overheating?  Call EXAIR!

Or email (and call), as was the case in this application.  An end user in an overseas power plant uses a pneumatic positioner in their steam bypass system.  A pneumatic positioner can best be correlated to a PWM (Pulse Width Modulated) linear actuator.  It will take a supply signal of various forms and provide an output to an actuator or valve, most often to regulate pressure/flow.  So, why not just use a pressure regulator?  Because a pneumatic positoner can be programmed to respond differently to different inputs, and it can function in real time.  Meaning, that when the supply signal reaches a certain threshold the output action can be preset, adding precision to a pneumatically controlled application.  And, as application needs change, the adjustments can be automated.

Some pneumatic positioners are pneumatically controlled (the input signal is a compressed air pressure), but most are electronic.  The end user in this case was using an electrically controlled unit that was experiencing shutdown due to the high ambient temperatures.

When cooling in an application like this it is important to consider the needs (and restrictions) of the application.  To blow ambient air was not an option because of the high ambient temperature, so a Super Air Amplifier, Super Air Knife, or Super Air Nozzle weren’t viable options.  And, the pneumatic positioner was exposed to ambient conditions, with no intent to place within an enclosure.

The lack of an enclosure ruled out a Cabinet Cooler, but a Vortex Tube based solution was still possible.  When considering the heat load and required cooling capacity, the end user determined that with less than 200 BTU/hr. of cooling, the application should run flawlessly. This customer also expressed they may have fluctuations in there pressure supply, and ambient temperatures which would create the need to provide a larger Btu/Hr Vortex Tube in order toake up for lower pressures and increased temperatures. Our smallest Vortex Tube is capable of producing 550 Btu/Hr and was recommended for a successful application.

If you have an application problem in need of compressed air solutions, call an EXAIR Application Engineer.

Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE