Vortex Tubes for spot cooling

Cooling with Compressed Air

Vortex Tubes     |     Cold Air Guns       

Vortex Tubes are available in many sizes offering a range of cooling capacities. Vortex Tubes || Vortex Tubes are available in a wide range of sizes to meet the needs of many process and spot cooling applications. Vortex Tubes offer cooling capacities beyond those available from our Cold Air Guns. Features: Cool without refrigerants (CFCs/HCFCs) or moving parts for reliable, trouble- free operation. Use no electricity -- intrinsically safe, no RF interference. Compact and lightweight for easy installation -- even in tight areas.

Vortex Tube Phenomenon The vortex tube was discovered in 1930 by French physicist Georges Ranque. Vortec was the first company to develop this phenomenon into practical, effective cooling solutions for industrial applications. Here's how it works. Fluid that rotates about an axis -- like a tornado -- is called a vortex. A vortex tube creates a vortex from compressed air and separates it into two air streams -- one hot and one cold. Compressed air enters a cylindrical generator which is proportionately larger than the hot (long) tube where it causes the air to rotate. Then, the rotating air is forced down the inner walls of the hot tube at speeds reaching 1,000,000 rpm. At the end of the hot tube, a small portion of this air exits through a needle valve as hot air exhaust. The remaining air is forced back through the center of the incoming air stream at a slower speed. The heat in the slower moving air is transferred to the faster moving incoming air. This super-cooled air flows through the center of the generator and exits through the cold air exhaust port.

Vortex tube products have been solving industrial cooling problems for years. Using only filtered, factory compressed air as a power source, they convert ordinary compressed air into two air streams -- one hot and one cold. At 100 PSIG (6.9 Bar) and 70° F (21° C) inlet temperature, a vortex tube can produce refrigeration up to 6000 BTUH (1512 kcal/H) or temperatures to -40° F (-40° C).

Choose one of our Cold Air Guns for quick, easy installation or the model from our complete vortex tube line that best fits the specific needs of your application.

Vortex Tube Models and Performance Specifications:
	COMPRESSED AIR PRESSURE -- 100 PSIG			COMPRESSED AIR PRESSURE -- 6.9 BAR
	SCFM CONSUMPTION	TEMP. DROP ° F*		SLPM	TEMP. DROP ° C*
MODEL NO.			BTUH	CONSUMPTION		KCAL/H
106-2-H	2	61	100	57	34	25
106-4-H	4	80	255	113	44	64
106-8-H	8	81	400	227	45	101
208-11-H	11	84	640	312	47	161
208-15-H	15	84	900	425	47	227
208-25-H	25	67	1500	708	37	378
308-35-H	35	76	2650	992	42	668
328-50-H	50	79	3000	1416	44	756
328-75-H	75	85	4500	2125	47	1134
328-100-H	100	78	6000	2833	43	1512

* Airflow temperature can be dropped up to an additional 20° F (11° C). Colder airflow temperatures are produced by adjusting the needle valve to increase the hot airflow. The needle valve is located in the hot exhaust. Vortex Tubes produce less airflow at colder temperatures and have less BTUH (kcal/H) capacity.

Accessories:

MODEL NO.	DESCRIPTION
106GEN	Individual Generator for 106 Vortex Tube -- specify 2, 4 or 8 SCFM
106MC	Cold End Muffler for 106 Vortex Tube
208GEN	Individual Generator for 208 Vortex Tube -- specify 11, 15, 25 or 35 SCFM
208MC	Cold End Muffler for 208 or 308 Vortex Tubes
208MH	Hot End Muffler for 106 or 208 Vortex Tubes
308MH	Hot End Muffler for 308 Vortex Tube
328M	Cold or Hot End Muffler for 328 Vortex Tube
328XB	Individual Generator for 328 Vortex Tube -- specify 50, 75 or 100 SCFM

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Cold Air Guns || Cold Air Guns incorporate a vortex tube in a system designed to fit the needs of many common vortex tube applications.	Use the Model 610 Adjustable Cold Air Gun to increase feed rates and tool life, or cool parts and industrial processes.
Features: Cool without refrigerants (CFCs/HCFCs) or moving parts for reliable, trouble-free operation. Use no electricity -- intrinsically safe, no RF interference. Include an integral muffler for quiet operation -- within OSHA noise specifications. Are powered by filtered compressed air.

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Model 610 Adjustable Cold Air Gun
The Model 610 Adjustable Cold Air Gun is ideal for use in machining applications and for cooling parts and industrial processes. Model 610's adjustable feature allows you to set the cold airflow rate (BTUH) at optimum levels for your application. The Adjustable Cold Air Gun's maximum temperature drop is 100° F (55.6° C) below inlet air temperature and the maximum cooling capacity is 1500 BTUH (378 kcal/H). Model 610's compressed air supply requirement is 15 SCFM (425 SLPM) at 100 PSIG (6.9 Bar).

Model 610 comes complete with a flexible nozzle for directing cold air and a magnetic base for quick, easy installation and use.
ITW Vortec's Mini Cold Air Gun is designed to shave hours off your dry surface grinding operations. By providing a contamination-free source of cooling, it effectively cools parts to reduce normalization time, hold tighter tolerances, reduce wheel loading and improve surface finish quality. Its adjustable magnetic base allows instant installation and positioning near the wheel for maximum cooling performance. Its compact size won't interfere with grinding operations. Model 608's compressed air supply requirement is 8 SCFM (227 SLPM) at 100 PSIG (6.9 Bar).

Model 608 Mini Cold Air Gun Model 608 Mini Cold Air Gun is designed to shave hours off your dry surface grinding operations. By providing a contamination-free source of cooling, it effectively cools parts to reduce normalization time, hold tighter tolerances, reduce wheel loading and improve surface finish quality. Its adjustable magnetic base allows instant installation and positioning near the wheel for maximum cooling performance. Its compact size won't interfere with grinding operations. Model 608's compressed air supply requirement is 8 SCFM (227 SLPM) at 100 PSIG (6.9 Bar).

Drastically reduce dry surface grinding production times with the Model 608 Mini Cold Air Gun

Models:

Model no.	Description
610	Adjustable Cold Air Gun, includes Magnetic Base and 5-micron Auto-Drain filter
610-1	Adjustable Cold Air Gun only
608	Mini Cold Air Gun, includes Adjustable Magnetic Base and 5-micron Auto-Drain filter

Options:

Model no.	Description
611-FNU	Frost-Free Nozzle Upgrade Kit
610-30	Dual-Point Flexible Nozzle (two cold air outlets)

Model 424 Thread Guard® Needle Cooler
Watch your piece rate jump with Model 424 Thread Guard®. The Thread Guard delivers a continuous stream of cold air onto the sewing machine needle to virtually eliminate downtime caused by needle breakage and thread burning caused by overheating. It's effective even in the most challenging sewing operations including belt loops and tough materials. Cooling also prevents holes caused by hot needles burning synthetic fabrics. Model 424's compressed air supply requirement is 4 SCFM (113 SLPM) at 100 PSIG (6.9 Bar).
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Operation
Any fluid that flows and rotates about an axis such as a tornado, is called a vortex. A vortex tube creates a vortex and separates it into two air streams-one hot and one cold. Figure 1 shows how a vortex tube works. Compressed air enters a cylindrical generator which is proportionately larger than the hot (long) tube. The generator causes the air to spiral. The spiraling air is forced down the inner walls of the hot tube at speeds reaching 1,000,000 rpm. At the end of the hot tube, a small portion of this air exits through a needle valve as hot air. The remaining air is forced back through the center of the incoming air stream but at a slower speed. The heat in slower moving air is transferred to the faster moving incoming air. This super-cooled air flows through the center of the generator and exits through the cold air exhaust port.

Temperature Separation Effects
The Vortex Tube Creates two types of vortices: free and forced. In a free vortex (like a whirlpool) the angular velocity of a fluid particle increases as it moves toward the Center of the vortex-that is, the closer a particle of fluid is to the center of a vortex, the faster it rotates. In a forced vortex, the velocity is directly, proportional to the radius of the vortex-the closer the center, the slower the velocity.

In a vortex tube, the outer (hot) air stream is a free vortex. The inner (cold) air stream is a forced vortex. The rotational movement of the forced vortex is controlled by the free vortex (hot air stream). The turbulence of both the hot and cold air streams cause the layers to be locked together in a single, rotational mass.

The inner air stream flows through the hollow core of the outer air stream at a slower velocity than the outer air stream. Since the energy is proportional to the square of the velocity, the cold air stream loses its energy by heat transfer. This allows energy to flow from the inner air stream to the outer air stream as heat creating a cold inner air stream.

Cold Fraction
The percentage of total input air volume released through the cold air exhaust of a Vortex Tube is called the Cold Fraction. A valve located in the hot air exhaust of the Vortex Tube controls the Cold Fraction. For example, if the total compressed air input is 15 SCFM (424.5 SLPM) and the Cold Fraction is 70%, the amount of air exiting the cold end wilt be 10.5 SCFM (297.2 SLPM); 4.5 SCFM (127.4 SLPM) exits the hot end.

Cold Fractions of 60-80% produce maximum efficiency-greatest power (BTUH) output- and are ideal for cooling machining operations, electrical controls and enclosures, liquid baths and workers. Low Cold Fractions (less than 50%) have reduced airflows and produce the lowest temperatures for cooling glass, laboratory experiments and for testing electronic components.

   

Table 1. Humidity Effects

Temperature ° F(° C)		110(43)	100(38)	90(32)	80(27)	70(21)	60(16)	50(10)
Saturation, gr/lb(gr/kg)		375(827)	295(650)	217(478)	154(339)	111(245)	77(170)	54(119)
Temperature ° F(° C)	40(4)	30(-1)	20(-7)	10(-12)	0(-18)	-10(-23)	-20(-29)	-30(-34)
Saturation, gr/lb(gr/kg)	37(82)	24(53)	15(33)	9(20)	5.5(12)	3.2(7)	1.8(4)	1.0(2)

Table 2. Saturation Moisture Content

Temperature ° F(° C)	110(43)	100(38)	90(32)	80(27)	70(21)	60(16)	50(10)	40(4)	30(-1)	20(-7)
Saturation, gr/lb(gr/kg)	48(106)	38(84)	28(62)	20(44)	14(31)	9.8(22)	6.9(15)	4.7(10)	3.1(7)	1.9(4)

Humidity Effects
A Vortex Tube does not separate humidity between hot and cold air-it remains the same as the compressed air input. If the dew point of the air is higher than its temperature, the moisture will condense and/or freeze. The table above shows the amount of moisture in grains (1 grain = 0.000143 pound) that one pound of air can hold in the saturated vapor state as a function of air temperature at one atmosphere, 14.7 PSIG (1 D Bar). Table 1 shows when condensation will begin at various temperatures and moisture contents. For example, if the moisture content is 14 gr/lb (31 gr/kg), condensation will begin when the temperature of the cold air falls below 19 ° F(-7.2° C) At 5 gr/lb (11 gr/kg), condensation will begin at -1° F (-18° C).

If you compare Tables 1 and 2, you can predict the amount of moisture in the compressed air and the temperature at which the moisture will begin to precipitate or freeze in the cold air. For example, if the compressed air is after-cooled to 80° F (27° C) after compression and the precipitated water is drained off, Table 2 shows that the air will hold 20 grains of water vapor per pound of dry air. When this expands in the Vortex Tube, Table 1 shows that precipitation begins in the cold air when the temperature falls below 26° F (-3.3° C) when the pressure is 14.7 PSIG (1.0 Bar)

If the compressed air is cooled under pressure by a chiller to 40° F (4.4° C), it will then hold 4.7 gr/lb of water vapor (see Table 2). When expanded in the Vortex Tube, precipitation will occur at -3° F (-19° C) at 14.4 PSIG (1 .0 Bar).

If some moisture precipitates in the cold air, the temperature of the cold air will rise about 0.75° F (0.4° C) for each grain of moisture precipitated. This is because some of the sensible (apparent) refrigeration of the cold air is consumed in producing latent refrigeration of the moisture. This refrigeration is not lost, but reappears in the cold air as it warms after leaving the Vortex Tube when the precipitated moisture evaporates.

For example, if a 208-15-H Vortex Tube is operating at 100 PSIG (6.9 Bar), it will achieve a cold end temperature of approximately -15° F (-26° C) at a dew point of -40° F (-40° C) and a cold end flow rate of 10.3 SCF (291.5 SLPM). But if the compressed air supply was not dried, and only after-cooled to 80° F (27° C), it would contain 20 gr/lb of moisture. But once the cold air reaches -15° F (-26° C), Table 1 shows that the air can only hold 2.5 grains of moisture and 17.5 grains (20 - 2.5) of moisture would precipitate out. This would cause a temperature rise of over 13° F (7.2° C) causing a loss of 144 BTUH (36 kcal/H).

Tables 1 and 2 show that condensation will not normally occur at moderately cold temperatures. When temperatures are below freezing, the condensation is in the form of snow. This snow has a sticky quality from oil vapor and will eventually collect and block air passages. For continuous operation at low temperatures, use an air dryer or inject an antifreeze mist into the input air. When selecting a dryer, do not use chemical desiccant dyers such as silica-gel or molecular sieve types. They tend to heat the compressed air and cause refrigeration losses.

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