Tag: process cooling

High Temperature Vortex Tube for Sensor Cooling

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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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Mini Cooler Provides Cooling Solution In Induction Heating Process

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I was recently contacted by an automation company using an induction heating process to heat the flared end of 2 nickel alloy parts, less than 1″ long with a 7/8″ flared end. The parts are only a few inches apart and they are heating the flared end to around 170°C and holding the temperature for about 1 second. They then cool the flared ends by using compressed air blowing through a homemade manifold with drilled holes directing the air across the parts to cool them to room temperature. The homemade manifolds were being used because they were behind schedule on the original project and needed a “quick fix”. While the current setup was working, they were using approximately 30 SCFM of compressed air with a cooling time of around 10 seconds and the operation was very loud. Looking to make some improvements to reduce the amount of air they were using, decrease the cooling cycle and lower the sound level, they turned to EXAIR for assistance.

I recommended they use our Model # 3308 Mini Cooler System with two cold outlets. The Mini Cooler incorporates a Vortex Tube and provides a 50°F temperature drop from compressed air supply temperature – in this case the outlet temperature from the Mini Cooler will be about 30°F. The dual point hose kit splits the cold airflow into two separate airstreams, allowing for a wider treatment area, or in this particular application, the ability to cool two separate parts with just one device. The unit consumes only 8 SCFM @ 100 PSIG, much less than the current 30 SCFM the customer is using now, and produces a low sound level of only 76 dBA. It also incorporates a swivel magnetic base, so installation is simple, making it easy to replace the existing setup.

Mini Cooler
Model 3308 Mini Cooler System – includes Mini Cooler, Dual Point Hose Kit, Swivel Mag Base and Filter Separator.

If you have a cooling application you would like to discuss, please contact one of our application engineers at 800-903-9247 for assistance.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

 

Vortex Tube Cold Fractions

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Vortex Tubes are the perfect solution when dealing with a variety of spot cooling applications. They use compressed air to produce a cold air stream and a hot air stream, with temperatures ranging from as low as -50°F  up to +260°F (based on ambient supply temperature) and providing as much as 10,200 Btu/hr. of cooling capacity. By simply adjusting the valve in the hot end of the Vortex Tube, you are able to control the “cold fraction” which is the percentage of air consumed by the vortex tube that is exhausted as cold air versus the amount of air exhausted as hot air. Our small, medium and large Vortex Tubes provide the same temperature drop and rise, it’s the volume of air that changes with the various sizes.

Vortex Tubes
Vortex Tubes are available in small, medium and large sizes with various flows and cooling capacities.

When looking at the below performance chart, you will see that “Pressure Supply” and “Cold Fraction %” setting all play a part in changing the performance of the Vortex Tubes. Take for example, an operating pressure of 100 PSIG and cold fraction setting of 20%, you will see a 123°F drop on the cold side versus a 26°F temperature rise on the hot side. By the using the same Vortex Tube and keeping the operating pressure at 100 PSIG but changing the cold fraction to 80%, you will now see a 54°F temperature drop on the cold side and a 191° rise at the hot end.

Vortex Tube Performance Data
Vortex Tube Performance Chart

We’ve looked at how the cold fraction changes the temperature, but how does it change the flow for the various Models?

Say you are using a Model # 3240 Medium Vortex Tube which consumes 40 SCFM @ 100 PSIG. Again with the cold fraction set at 80% (80% of the consumed compressed air out of the cold end), you would flow 32 SCFM at the cold air exhaust.

40 SCFM x 0.8 (80% CF) = 32 SCFM

Using the same Model # 3240 Medium Vortex Tube but now with a 20% cold fraction (20% of consumed compressed air out of the cold end), you would flow 8 SCFM at the cold exhaust.

40 SCFM x 0.20 (20% CF) = 8 SCFM

As you can see, to achieve the colder air temperatures, the volume of cold air being exhausted is reduced as well. This is important to consider when making a Model selection. Some other considerations would be the operating pressure which you can see also has a significant effect on performance. Also the compressed air supply temperature because the above temperatures are temperature differentials, so in the example of the 80% cold fraction there is a 115F temperature drop from your inlet compressed air temperature.

If you need additional assistance, you can always contact myself or another application engineer and we would be happy to make the best selection to fit your specific need.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

 

Calculating Air Flow to Cool Manufacturing Processes

Published on by Lee EvansLeave a comment
IMG_7065
This application needed a way to cool steel plates from 150C to 70C

I’ve written before about using ambient air to cool an application, calculating the required airflow to maintain a temperature.  And, I was recently contacted by an end user in India in need of a way to cool electromagnets in a similar application.

The need was to reduce the temperature of high manganese steel plates (dimensions of 1800mm x 800mm x 500mm) from 150°C to less than 70°C, using air at 40°C.  These steel plates have a specific heat of 0.5107896 J/g°C, weigh 120kg each, and protect the coil and insulation of the electromagnets in this process.  So, just as was the case in previous applications, we started with the process shown below.

heat load calc process
Heat load calculation process

In doing so, we calculated a heat load of 279,245 BTU/hr., which will require an air volume of 1,805 CFM to cool as needed.  (Click the image below for an expanded view of the calculations)

Electromagnet calculations
Heat load calculations

The recommendation to provide this cooling was the use of (6) 120022 Super Air Amplifiers, operated at 80 PSIG and installed along the length of the plates to distribute airflow.  As we can see in the chart below, each 120022 Super Air Amplifier will move an air volume of 341 CFM at the outlet of the unit, making (6) of these units suitable for this application.  And, if we consider entrainment of additional ambient air at distances away from the outlet of the 120022 Super Air Amplifier, we can consider these units may cool the steel faster than the 1 minute cycle time used for calculation purposes.

air amp chart
Super Air Amplifier performance chart

This application is a great example of how an engineered compressed air solution can remove process disturbances effectively, and efficiently solve problems.  If you have a similar application or even one that is entirely different, contact an EXAIR Application Engineer.

Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE