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Vortex Tubes

Cold air to -46°C (-50°F) from your compressed air supply – with no moving parts!

What Is A Vortex Tube?

A low cost, reliable, maintenance free solution to a variety of industrial spot cooling problems. Using an ordinary supply of compressed air as a power source, vortex tubes create two streams of air, one hot and one cold, with no moving parts. Vortex tubes can produce:

• Temperatures from -46° to +127°C (-50° to +260°F)
• Flow rates from 1 to 150 SCFM (28 to 4,248 SLPM)
• Refrigeration up to 10,200 Btu/hr. (2,570 Kcal/hr.)

Temperatures, flows and refrigeration are adjustable over a wide range using the control valve on the hot end exhaust.

EXAIR Vortex Tubes are constructed of stainless steel. The wear resistance of stainless steel, as well as its resistance to corrosion and oxidation, assures that EXAIR Vortex Tubes will provide years of reliable, maintenance-free operation.

How A Vortex Tube Works

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 centre 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.

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 maximises 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 utilise the 32XX series Vortex Tube. Certain “cryogenic” applications, i.e., cooling lab samples, circuit testing, are best served by the 34XX 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 28°C (50°F) below compressed air temperature.

If you are unsure of your flow and temperature requirements, we recommend 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.

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 Temperatures

High temperature vortex tubes for ambient temperatures above 93°C (200°F) are available. Standard vortex tubes are for ambient temperatures up to 52°C (125°F). Contact CAA for details.

Pre-set 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 CAA.

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 ±0.5°C (±1°F).

Pressure Supply Cold Fraction %
PSIG 20 30 40 50 60 70 80
20 62 60 56 51 44 36 28
15 25 36 50 64 83 107
40 88 85 80 73 63 52 38
21 35 52 71 92 117 147
60 104 100 93 84 73 60 46
24 40 59 80 104 132 166
80 115 110 102 92 80 66 50
25 43 63 86 113 143 180
100 123 118 110 100 86 71 54
26 45 67 90 119 151 191
120 129 124 116 104 91 74 55
26 46 69 94 123 156 195

Numbers in shaded area give temperature drop of cold air °F
Numbers in white area give temperature rise of hot air °F

Pressure Supply Cold Fraction % (METRIC)
BAR 20 30 40 50 60 70 80
1.4 34.4 33.3 31.1 28.3 24.4 20 15.6
8.3 13.9 20 28.3 35.6 46.1 59.4
2 40.9 39.6 37.1 33.8 29.2 24 18.1
9.8 16.4 24 33.3 42.6 54.6 69.5
3 50.4 48.7 45.7 41.6 36 29.7 21.9
12 19.9 29.6 40.3 52.3 66.5 83.5
4 56.9 54.7 50.9 46.1 40 32.9 25.1
13.2 21.9 32.4 43.9 57.1 72.5 91.2
5 61.6 59 54.8 49.4 43 35.4 26.9
13.7 23.3 34.2 46.5 60.9 77.2 97.1
6 65.4 62.7 58.2 52.7 45.6 37.6 28.6
14.1 24.3 35.8 48.6 63.9 81 102.1
7 68.6 65.8 61.4 55.7 48 39.6 30
14.4 25.1 37.3 50.2 66.3 84.2 106.3
8 71.1 68.2 63.8 57.3 50 40.8 30.4
14.4 25.4 38.1 51.8 67.9 86.1 107.9

Numbers in shaded area give temperature drop of cold air °C
Numbers in white area give 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 2.8°C (5°F).

Filtration: The use of clean air is essential, and filtration of 25 microns or less is recommended. EXAIR filters contain a 5 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).

Applications

  • 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

Advantages

  • No moving parts
  • No electricity or chemicals
  • Small, lightweight
  • Low cost
  • Maintenance free
  • Instant cold air
  • Durable – stainless steel
  • Adjustable temperature
  • Interchangeable generators

A 1/4 ton of refrigeration in the palm of your hand!

A Model 3225 Vortex Tube keeps plastic dishwasher arms cool during ultrasonic welding.

A pair of medium vortex tubes cool a solenoid coil after a welding operation.

Vortex Tubes with Mufflers attached set chocolate in moulds.

Special high temperature vortex tubes keep a boroscope lens cool while inserted into a 650°C (1200°F) boiler porthole.

(4) Model 3250 Vortex Tubes cool the cutting knives in this pelletiser to prevent irregular shapes.

A Model 3215 Vortex Tube cools a die on a medical tube forming machine.

Application Spotlights

Cooling Vacuum Formed Parts

The Problem

A manufacturer of major appliances vacuum forms the plastic interior shell of refrigerators. The deep draw of the plastic and complex geometry left the four corners unacceptably thin. The corners would tear during assembl...

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Cooling an Ultrasonic Weld

The Problem

A manufacturer of toothpaste seals the ends of plastic tubes with an ultrasonic welder prior to filling. As heat built up at the sealing jaw of the welder, release of the tubes was delayed. Tubes that were too hot would n...

Learn More

Cooling Blow Moulded Fuel Tanks

The Problem

Automobile fuel tanks are blow moulded, then clamped to a fixture to prevent distortion during the cooling cycle. The cooling time of over 3 minutes required for each tank created a bottleneck in the production process

Learn More

Cooling Small Parts After Brazing

The Problem

Air conditioner parts assembled on an automatic brazing machine must be cooled to handling temperature prior to removal. The machine was capable of brazing up to four hundred pieces per hour. However, the time required fo...

Learn More

Vortex Tubes 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?”. 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 -46°C (-50°F) and as high as +127°C (+260°F) 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.

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 shown below or the performance charts.  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 1133 SLPM).

Dimensions

Specifications

32XX series Vortex Tubes optimise temperature drop and airflow to produce maximum cooling power or Btu/hr. (Kcal/hr.). Specify 32XX series Vortex Tubes for most general cooling applications.

32XX Series Vortex Tube Specifications
Model SCFM* SLPM* Btu/hr.** Kcal/hr.** Size dBA***
3202 2 57 135 34 Small 68
3204 4 113 275 69 Small 70
3208 8 227 550 139 Small 76
3210 10 283 650 164 Medium 80
3215 15 425 1000 252 Medium 81
3225 25 708 1700 428 Medium 82
3230 30 850 2000 504 Medium 84
3240 40 1,133 2800 706 Medium 88
3250 50 1,416 3400 857 Large 94
3275 75 2,124 5100 1285 Large 96
3298 100 2,832 6800 1714 Large 96
3299 150 4,248 10,200 2570 Large 97

* 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

34XX series Vortex Tubes optimise temperature drop and airflow to produce maximum cooling power or Btu/hr. (Kcal/hr.). Specify 34XX series Vortex Tubes only where temperatures below -18°C (0°F) are desired.

34XX Series Vortex Tube Specifications
Model SCFM* SLPM* Btu/hr.** Kcal/hr.** Size dBA***
3402 2 57 ——– ——– Small 67
3404 4 113 ——– ——– Small 69
3408 8 227 ——– ——– Small 75
3410 10 283 ——– ——– Medium 78
3415 15 425 ——– ——– Medium 80
3425 25 708 ——– ——– Medium 82
3430 30 850 ——– ——– Medium 84
3440 40 1,133 ——– ——– Medium 87
3450 50 1,416 ——– ——– Large 93
3475 75 2,124 ——– ——– Large 96
3498 100 2,832 ——– ——– Large 96
3499 150 4,248 ——– ——– Large 96

* SCFM (SLPM) at 100 PSIG (6.9 Bar) Inlet Pressure
** Not Applicable. 34XX series Vortex Tubes are not normally used in air conditioning applications
*** Noise levels taken with hot and cold mufflers installed

Models

EXAIR Cooling Kits
Kits include a Vortex Tube, all generators, cold muffler, fitting, tubing and clips to duct cold air, and filter separator (with mounting bracket)
Model Description
BP3908 Small Cooling Kit up to 550 Btu/hr. (139 Kcal/hr.)
BP3930 Medium Cooling Kit up to 2,800 Btu/hr. (706 Kcal/hr.)
BP3998 Large Cooling Kit up to 10,200 Btu/hr. (2,570 Kcal/hr.)
Vortex Tubes For Maximum Refrigeration
Model Description
BP3202 Vortex Tube, 2 SCFM (57 SLPM), 135 Btu/hr. (34 Kcal/hr.) Small Size
BP3204 Vortex Tube, 4 SCFM (113 SLPM), 275 Btu/hr. (69 Kcal/hr.) Small Size
BP3208 Vortex Tube, 8 SCFM (227 SLPM), 550 Btu/hr. (139 Kcal/hr.) Small Size
BP3210 Vortex Tube, 10 SCFM (283 SLPM), 650 Btu/hr. (164 Kcal/hr.) Medium Size
BP3215 Vortex Tube, 15 SCFM (425 SLPM), 1,000 Btu/hr. (252 Kcal/hr.) Medium Size
BP3225 Vortex Tube, 25 SCFM (708 SLPM), 1,700 Btu/hr. (428 Kcal/hr.) Medium Size
BP3230 Vortex Tube, 30 SCFM (850 SLPM), 2,000 Btu/hr. (504 Kcal/hr.) Medium Size
BP3240 Vortex Tube, 40 SCFM (1,133 SLPM), 2,800 Btu/hr. (706 Kcal/hr.) Medium Size
BP3250 Vortex Tube, 50 SCFM (1,416 SLPM), 3,400 Btu/hr. (857 Kcal/hr.) Large Size
BP3275 Vortex Tube, 75 SCFM (2,124 SLPM), 5,100 Btu/hr. (1,285 Kcal/hr.) Large Size
BP3298 Vortex Tube, 100 SCFM (2,832 SLPM), 6,800 Btu/hr. (1,714 Kcal/hr.) Large Size
BP3299 Vortex Tube, 150 SCFM (4,248 SLPM), 10,200 Btu/hr. (2,570 Kcal/hr.) Large Size
Vortex Tubes For Maximum Cold Temperature
Model Description
BP3402 Vortex Tube, 2 SCFM (57 SLPM) Small Size
BP3404 Vortex Tube, 4 SCFM (113 SLPM) Small Size
BP3408 Vortex Tube, 8 SCFM (227 SLPM) Small Size
BP3410 Vortex Tube, 10 SCFM (283 SLPM) Medium Size
BP3415 Vortex Tube, 15 SCFM (425 SLPM) Medium Size
BP3425 Vortex Tube, 25 SCFM (708 SLPM) Medium Size
BP3430 Vortex Tube, 30 SCFM (850 SLPM) Medium Size
BP3440 Vortex Tube, 40 SCFM (1,133 SLPM) Medium Size
BP3450 Vortex Tube, 50 SCFM (1,416 SLPM) Large Size
BP3475 Vortex Tube, 75 SCFM (2,124 SLPM) Large Size
BP3498 Vortex Tube, 100 SCFM (2,832 SLPM) Large Size
BP3499 Vortex Tube, 150 SCFM (4,248 SLPM) Large Size
Vortex Tube Mufflers & Generator Kits
Model# Description
3905 Cold Muffler for 2 to 8 SCFM (57 to 227 SLPM) Small Vortex Tube
3901 Cold Muffler for 10 to 40 SCFM (283 to 1,133 SLPM) Medium Vortex Tube
3906 Cold Muffler for 50 to 150 SCFM (1,416 to 4,248 SLPM) Large Vortex Tube
3903 Hot Muffler for 2 to 40 SCFM (57 to 1,133 SLPM) Small & Medium Vortex Tube
3907 Hot Muffler for 50 to 150 SCFM (1,416 to 4,248 SLPM) Large Vortex Tube
3909 Generator Kit for 2 to 8 SCFM (57 to 227 SLPM) Small Vortex Tube
3902 Generator Kit for 10 to 40 SCFM (283 to 1,133 SLPM) Medium Vortex Tube
3910 Generator Kit for 50 to 150 SCFM (1,416 to 4,248 SLPM) Large Vortex Tube
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)
       Example:
      15-R = 15 SCFM Generator for max. refrigeration
      50-C = 50 SCFM Generator for max. cold temperature

Accessories

Filters, Regulators, Valves & More

With proper filtration of dirt, moisture and oil from the compressed air supply, EXAIR compressed air products will operate for years with no maintenance required. Use a 5 micron or smaller filter separator on the compressed air supply. To prevent problems associated with oil, use a 0.03 micron or smaller oil removal filter on the compressed air supply. Pressure regulators permit easy selection of the operating pressure, providing infinite control of flow, force and air consumption.

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Installation and Maintenance Guides

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Vortex Tubes

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Vortex Tubes & Spot Cooling PDF Brochure

CAD Drawings

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