Model 3225 Vortex Tube (25 SCFM)
- Cooling electronic controls
- Cooling machining operations
- Cooling CCTV cameras
- Setting hot melts
- Cooling soldered parts
- Cooling gas samples
- Electronic component cooling
- Cooling heat seals
- Cooling environmental chambers
- No moving parts
- No electricity or chemicals
- Small, lightweight
- Low cost
- Maintenance free
- Instant cold air
- Durable - stainless steel
- Adjustable temperature
- Interchangeable generators
|3905||Cold Muffler for 2 through 8 SCFM (57 - 227 SLPM) Vortex Tube, Small Size|
|3901||Cold Muffler for 10 through 40 SCFM (283 - 1,133 SLPM) Vortex Tube, Medium Size|
|3906||Cold Muffler for 50 through 150 SCFM (1,416 - 4,248 SLPM) Vortex Tube, Large Size|
|3903||Hot Muffler for 2 through 40 SCFM (57 - 1,133 SLPM) Vortex Tube, Small & Medium Size|
|3907||Hot Muffler for 50 through 150 SCFM (1,416 - 4,248 SLPM) Vortex Tube, Large Size|
|3909||Generator Kit for 2 through 8 SCFM (57 - 227 SLPM) Vortex Tube, Small Size|
|3902||Generator Kit for 10 through 40 SCFM (283 - 1,133 SLPM) Vortex Tube, Medium Size|
|3910||Generator Kit for 50 through 150 SCFM (1,416 - 4,248 SLPM) Vortex Tube, Large Size|
Generator Kits ordered with a vortex tube include all generators for the specified tube. Permits setting the vortex tube for all capacities and styles.
Generator Only —Specify capacity (SCFM) and style (“R” for max. refrigeration, “C” for max. cold temperature).
15-R = 15 SCFM Generator for max. refrigeration
50-C = 50 SCFM Generator for max. cold temperature
Vortex Tube Performance
The Vortex Tube Performance Charts below give approximate temperature drops (and rises) from inlet air temperature produced by a vortex tube set at each cold fraction. Assuming no fluctuation of inlet temperature or pressure, a vortex tube will reliably maintain temperature within ±1°F.
Cold Fraction %
|Numbers in shaded area show temperature drop of cold air (°F).|
|Numbers in unshaded area show temperature rise of hot air (°F).|
Cold Fraction % (METRIC)
|Numbers in shaded area show temperature drop of cold air (°C).|
|Numbers in unshaded area show temperature rise of hot air (°C).|
Back Pressure: The performance of a vortex tube deteriorates with back pressure on the cold air exhaust. Low back pressure, up to 2 PSIG (.1 BAR), will not change performance. 5 PSIG (.3 BAR) will change performance by approximately 5°F (2.8°C).
Filtration: The use of clean air is essential, and filtration of 25 microns or less is recommended. EXAIR filters contain a five micron element and are properly sized for flow.
Inlet Air Temperature: A vortex tube provides a temperature drop from supply air temperature (see Performance Charts above). Elevated inlet temperatures will produce a corresponding rise in cold air temperatures.
Noise Muffling: EXAIR offers mufflers for both the hot and cold air discharge. Normally, muffling is not required if the cold air is ducted.
Regulation: For best performance, use line pressures of 80 to 110 PSIG (5.5 to 7.6 BAR). Maximum pressure rating is 250 PSIG (17.2 BAR), minimum 20 PSIG (1.4 BAR).
Vortex Tube Specifications
3200 Series Vortex Tube Specifications
|3200 series Vortex Tubes optimize temperature drop and airflow to produce maximum cooling power or Btu/hr. (Kcal/hr.). Specify 3200 series Vortex Tubes for most general cooling applications.|
* SCFM (SLPM) at 100 PSIG (6.9 BAR) Inlet Pressure
** Btu/hr. (Kcal/hr.) Cooling Capacity at 100 PSIG (6.9 BAR)
*** Noise levels taken with hot and cold mufflers installed.
3400 Series Vortex Tube Specifications
|3400 series Vortex Tubes provide lowest cold air temperatures, but at low cold airflow (when less than a 50% cold fraction is used). Specify 3400 series Vortex Tubes only where temperatures below 0° (-18°C) are desired.|
* SCFM (SLPM) at 100 PSIG (6.9 BAR) Inlet Pressure
** Not Applicable. 3400 series Vortex Tubes are not normally used in air conditioning applications.
***Noise levels taken with hot and cold mufflers installed.
Vortex Tube Dimensions
How Vortex Tubes Work
Compressed air, normally 80-100 PSIG (5.5 - 6.9 BAR), is ejected tangentially through a generator into the vortex spin chamber. At up to 1,000,000 RPM, this air stream revolves toward the hot end where some escapes through the control valve. The remaining air, still spinning, is forced back through the center of this outer vortex. The inner stream gives off kinetic energy in the form of heat to the outer stream and exits the vortex tube as cold air. The outer stream exits the opposite end as hot air.
Vortex Tube Styles
EXAIR Products Using Vortex Tubes
Over the years, the basic vortex tube has been used in virtually hundreds of industrial cooling applications. A few have become so popular as to warrant the development of an “applied product” designed to suit the specific application. These products include the Adjustable Spot Cooler, Mini Cooler, Cold Gun and Cabinet Coolers.
High temperature vortex tubes for ambient temperatures above 200°F (93°C) are available. Standard vortex tubes are for ambient temperatures up to 125°F (52°C). Contact an Application Engineer at 1-800-903-9247 for more details.
Preset Vortex Tubes
EXAIR can provide vortex tubes preset to any combination of flow and temperature desired. To prevent tampering with the desired setting, a drilled orifice that replaces the adjustable hot valve is available. For more information, please contact an Application Engineer.
Selecting the Right Vortex Tube
EXAIR Vortex Tubes are available in three sizes. Each size can produce a number of flow rates, as determined by a small internal part called a generator. If Btu/hr. (Kcal/hr.) requirements, or flow and temperature requirements are known, simply select the appropriate vortex tube according to the specification information on the Specifications table or the Performance charts shown in FEATURES above.
Keep in mind that the vortex generators are interchangeable. If, for example, a Model 3215 Vortex Tube does not provide sufficient cooling, you need only change generators within the vortex tube to upgrade the flow rate from 15 to 25, 30 or 40 SCFM (425 to 708, 850 or 1,133 SLPM).
Vortex Tube Standards and Certifications
EXAIR Vortex Tubes comply with OSHA's Safety Requirements, the EU General Product Safety Directive (2001/95/EC) and meet the noise limitation requirements of the EU Machinery Directive (2006/42/EC).All sound level measurements are taken at 3 feet away.
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Controlling Temperature and Flow In A Vortex Tube
Cold airflow and temperature are easily controlled by adjusting the slotted valve in the hot air outlet. Opening the valve reduces the cold airflow and the cold air temperature. Closing the valve increases the cold airflow and the cold air temperature. The percentage of air directed to the cold outlet of the vortex tube is called the "cold fraction". In most applications, a cold fraction of 80% produces a combination of cold flow rate and temperature drop that maximizes refrigeration, or Btu/hr. (Kcal/hr.), output of a vortex tube. While low cold fractions (less than 50%) produce lowest temperatures, cold airflow volume is sacrificed to achieve them.
Most industrial applications, i.e., process cooling, part cooling, chamber cooling, require maximum refrigeration and utilize the 3200 series Vortex Tube. Certain "cryogenic" applications, i.e., cooling lab samples, circuit testing, are best served by the 3400 series Vortex Tube.
Setting a vortex tube is easy. Simply insert a thermometer in the cold air exhaust and set the temperature by adjusting the valve at the hot end. Maximum refrigeration (80% cold fraction) is achieved when cold air temperature is 50°F (28°C) below compressed air temperature.
If you are unsure of your flow and temperature requirements, EXAIR recommends the purchase of an EXAIR Cooling Kit. It contains a vortex tube, cold air muffler, air line filter and all generators required to experiment with the full range of airflows and temperatures.
A Phenomenon of Physics
The two questions we’re most often asked about the vortex tube are, “How long has it been around?” and “How does the thing work?” The following is a brief history and theory of the vortex tube.
The vortex tube was invented quite by accident in 1928. George Ranque, a French physics student, was experimenting with a vortex-type pump he had developed when he noticed warm air exhausting from one end, and cold air from the other. Ranque soon forgot about his pump and started a small firm to exploit the commercial potential for this strange device that produced hot and cold air with no moving parts. However, it soon failed and the vortex tube slipped into obscurity until 1945 when Rudolph Hilsch, a German physicist, published a widely read scientific paper on the device.
Much earlier, the great nineteenth century physicist, James Clerk Maxwell, postulated that since heat involves the movement of molecules, we might someday be able to get hot and cold air from the same device with the help of a “friendly little demon” who would sort out and separate the hot and cold molecules of air.
Thus, the vortex tube has been variously known as the “Ranque Vortex Tube”, the “Hilsch Tube”, the “Ranque-Hilsch Tube”, and “Maxwell’s Demon”. By any name, it has in recent years gained acceptance as a simple, reliable and low cost answer to a wide variety of industrial spot cooling problems.
A vortex tube uses compressed air as a power source, has no moving parts, and produces hot air from one end and cold air from the other. The volume and temperature of these two airstreams are adjustable with a valve built into the hot air exhaust. Temperatures as low as -50°F (-46°C) and as high as +260°F (+127°C) are possible.
Theories abound regarding the dynamics of a vortex tube. Here is one widely accepted explanation of the phenomenon:
Compressed air is supplied to the vortex tube and passes through nozzles that are tangent to an internal counterbore. These nozzles set the air in a vortex motion. This spinning stream of air turns 90° and passes down the hot tube in the form of a spinning shell, similar to a tornado. A valve at one end of the tube allows some of the warmed air to escape. What does not escape, heads back down the tube as a second vortex inside the low-pressure area of the larger vortex. This inner vortex loses heat and exhausts through the other end as cold air.
While one airstream moves up the tube and the other down it, both rotate in the same direction at the same angular velocity. That is, a particle in the inner stream completes one rotation in the same amount of time as a particle in the outer stream. However, because of the principle of conservation of angular momentum, the rotational speed of the smaller vortex might be expected to increase. (The conservation principle is demonstrated by spinning skaters who can slow or speed up their spin by extending or drawing in their arms.) But in the vortex tube, the speed of the inner vortex remains the same. Angular momentum has been lost from the inner vortex. The energy that is lost shows up as heat in the outer vortex. Thus the outer vortex becomes warm, and the inner vortex is cooled.