VORTEX TUBE HAVING AT LEAST TWO GENERATORS

Abstract

A vortex tube according to an embodiment of the present disclosure includes a cold and heat separation chamber; a cold air outlet provided at an end of the cold and heat separation chamber, a generator provided between the cold air outlet and the cold and heat separation chamber, a hot air outlet provided at another end of the cold and heat separation chamber and including a hot air adjusting valve, and an outer tube cover having a compressed air inlet and surrounding the cold and heat separation chamber at a predetermined gap while blocking the cold and heat separation chamber at an outside thereof, so that introduced compressed air can be supplied into the generator, wherein the compressed air flowing through the compressed air inlet generates rapid rotating wind by passing through the generator to be moved into the cold and heat separation chamber to separate cold and heat from each other.

Description

CROSS REFERENCE TO RELATED APPLICATIONS AND CLAIM OF PRIORITY

This application claims benefit under 35 U.S.C. 119(e), 120, 121, or 365(c), and is a National Stage entry from International Application No. PCT/KR2020/014715, filed Oct. 27, 2020, which claims priority to the benefit of Korean Patent Application No. 10-2020-0106553 filed in the Korean Intellectual Property Office on Aug. 24, 2020, the entire contents of which are incorporated herein by reference.

BACKGROUND

1. Technical Field

The present disclosure relates to a vortex tube and, more particularly, to a vortex tube having at least two generators to have improved performance when compared to a conventional vortex tube.

2. Background Art

The vortex tube (which is also called Ranque-Hilsch vortex tube) separates compressed air into a hot flow and a cold flow. When the compressed air is injected toward a swirl chamber, the air is accelerated and rotated at a high velocity. Only air rotated outside the tube is discharged from the tube due to a conical nozzle at the tube. The rest of the compressed air not discharged from the tube receives a force returning the air in the opposite direction and is returned to generate a vortex inside an outer vortex.

In other words, the vortex tube is a revolutionary cooling device that separates the supplied general compressed air (3-10 kg/cm²) into the hot and cold flows without electricity or any chemicals. When the compressed air is supplied into the vortex tube through a pipe, the compressed air is primarily supplied into the swirl chamber and is rotated at a high velocity of about 1,000,000 RPM. When the rotated air (first vortex) is moved toward a hot air outlet, a portion of the air is discharged through the hot air outlet (30° C.˜90° C.) by an adjusting valve and the rest of the air is returned from the adjusting valve to generate a second vortex and then is discharged through a cold air outlet. A flow of the second vortex loses heat as the second vortex passes through a lower pressure area inside the flow of the first vortex and is moved toward the cold air outlet.

The cold air discharged through the cold air outlet of the vortex tube is used in various industries. For example, the cold air is applied in various field, such as machine operation cooling, CNC milling cutting cooling, grinding, cutting, drill cooling, welding operation cooling in a dockyard, electronic product assembly cooling, and local cooling in a semiconductor factory.

The vortex tube has various advantages in addition to not requiring a refrigerant. For example, the vortex tube has advantages, such as improvement of work efficiency, being maintenance-free, clean cooling, tool life extension, easy maintenance, instantaneous cooling, etc.

Recently, a rapid cooling function is increasingly used in combination with a precision machine or an electronic device by using cold of the vortex tube. In this case, the temperature of the discharged cold becomes an important factor influencing performance.

However, although the vortex tube has been developed for over 150 years and has various uses, there have not been many attempts to improve the performance of the product by changing the structure thereof. The above problem is caused from reasons such that the vortex tube is not composed of many elements and the principle thereof is still not clearly known.

SUMMARY

Accordingly, the present disclosure has been made keeping in mind the above problems occurring in the related art, and an objective of the present disclosure is to provide a vortex tube configured to lower the temperature of discharged cold air, so that the efficiency of rapid cooling required for precision machinery or electronic devices among functions of the vortex tube is improved and precision operation without causing environmental pollution is possible.

Another objective of the present disclosure is to propose a vortex tube having at least two generators generating rapid rotating wind, the generators being partitioned by a sleeve, to lower the temperature of discharged cold air and thus to significantly improve the efficiency of rapid cooling.

A further objective of the present disclosure is to provide a vortex tube having an outer tube cover with a compressed air inlet surrounding a cold and heat separation chamber to facilitate storage and usage and to pre-cooling the cold and heat separation chamber with introduced compressed air.

A further objective of the present disclosure is to provide a vortex tube having a counterflow prevention cap inserted in a temperature adjusting valve in preparation for difficulty of discharging hot air to the outside of the vortex tube when the vortex tube is in an area where outside pressure is high.

An objective of the present disclosure is not limited to the above-mentioned objectives, and other objectives not mentioned will be clearly understood by one of ordinary skill in the art to which the present disclosure belongs (hereinbelow, ‘those skilled in the art’) in the following description.

In order to accomplish the above objective and to perform characteristic features of the present disclosure, the present disclosure provides a vortex tube configured as follows.

The vortex tube includes: a cold and heat separation chamber; a cold air outlet provided at an end of the cold and heat separation chamber; a generator provided between the cold air outlet and the cold and heat separation chamber; a hot air outlet provided at another end of the cold and heat separation chamber and including a hot air adjusting valve; and an outer tube cover having a compressed air inlet and surrounding the cold and heat separation chamber at a predetermined gap while blocking the cold and heat separation chamber at an outside thereof, so that introduced compressed air may be supplied into the generator, wherein the compressed air flowing through the compressed air inlet generates rapid rotating wind by passing through the generator to be moved into the cold and heat separation chamber to separate cold and heat from each other.

According to the above embodiment of the present disclosure, a counterflow prevention cap may be inserted in the hot air outlet including the hot air adjusting valve.

According to another embodiment of the present disclosure, a vortex tube may include: a cold and heat separation chamber; a cold air outlet provided at an end of the cold and heat separation chamber; a first generator, a sleeve, and a second generator provided between the cold air outlet and the cold and heat separation chamber; a compressed air inlet provided at a portion close to the first generator and the second generator and configured to supply compressed air into the first generator and the second generator; and a hot air outlet provided at another end of the cold and heat separation chamber and including a hot air adjusting valve, wherein an outlet of the sleeve may have a diameter larger than a diameter of an entrance of the cold air outlet and smaller than an inner diameter of each of the generators.

In addition, the vortex tube may include a third generator in addition to the second generator.

According to the present disclosure, the vortex tube is configured to lower the temperature of discharged cold air so that the efficiency of rapid cooling required for precision machinery or electronic devices among functions of the vortex tube is improved and precision operation without causing environmental pollution can be realized. Accordingly, since the vortex tube of the present disclosure includes at least two generators generating rapid rotating wind, which are partitioned by the sleeve, to lower the temperature of discharged cold, the efficiency of the rapid cooling can be significantly improved.

The vortex tube of the present disclosure includes the outer tube cover with the compressed air inlet surrounding the cold and heat separation chamber. Accordingly, storage and usage of the vortex tube can be easier and the cold and heat separation chamber can be pre-cooled with the introduced compressed air.

The vortex tube of the present disclosure includes the counterflow prevention cap inserted in the temperature adjusting valve. Accordingly, difficulty for hot air to be discharged from the outside of the vortex tube occurring when the vortex tube is in the area with high outside pressure can be prevented.

Effects of the present disclosure are not limited to the above-mentioned effects, and other effects not mentioned are clearly recognized by those skilled in the art in the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing a conventional vortex tube in contrast to the present disclosure.

FIG. 2 is a view showing a vortex tube having two generators according to a first embodiment of the present disclosure.

FIG. 3 is a view showing a vortex tube having two generators according to a second embodiment of the present disclosure.

FIG. 4 is a view showing a vortex tube having two generators according to a third embodiment of the present disclosure.

FIG. 5 is an exploded-perspective view showing the vortex tube of the third embodiment shown in FIG. 4.

FIG. 6 is a view showing a vortex tube having three generators according to a fourth embodiment of the present disclosure.

FIG. 7 is a view showing a hot air adjusting part of the above embodiments, the hot air adjusting part having a counterflow prevention cap inserted therein to efficiently discharge hot air.

DETAILED DESCRIPTION

In the following description, “cold ratio” is the ratio of the amount of air exiting a cold side to the amount of supplied compressed air. When the cold ratio is 40%, the ratio of the amount of the compressed air consumption to the amount of cold side discharged air is 100:40.

“Rapid rotating wind” means rotating air generated such that compressed air is supplied into a vortex tube through a pipe and is primarily supplied into a vortex (swirl) chamber to be rotated at an ultra-high velocity of about 1,000,000 RPM. The rapid rotating wind is referred to as “vortex” or “cyclone”. These terms have the same meaning.

In the following description, the structural or functional description specified to exemplary embodiments according to the concept of the present disclosure is intended to describe the exemplary embodiments, so it should be understood that the present disclosure may be variously embodied.

It should be understood that the exemplary embodiments according to the concept of the present disclosure are not limited to the embodiments which will be described hereinbelow with reference to the accompanying drawings, but various modifications, equivalents, additions and substitutions are possible, without departing from the scope and spirit of the invention.

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element, from another element. For instance, a first element discussed below could be termed a second element without departing from the teachings of the present disclosure. Similarly, the second element could also be termed the first element.

It will be understood that when an element is referred to as being “coupled” or “connected” to another element, it can be directly coupled or connected to the other element or intervening elements may be present therebetween.

In contrast, it should be understood that when an element is referred to as being “directly coupled” or “directly connected” to another element, there are no intervening elements present.

The terms used herein to describe a relationship between elements, for example, “between”, “directly between”, “adjacent”, or “directly adjacent” should be interpreted in the same manner as those described above.

In the following description, the same reference numerals will be used to refer to the same or like elements. Meanwhile, the terms used herein to describe a relationship between elements, for example, “between”, “directly between”, “adjacent”, or “directly adjacent” should be interpreted in the same manner as those described above.

An element expressed in a singular form in this specification may be plural elements unless it is necessarily singular in the context. The terms “comprise” and/or “comprising” means inclusion of a shape, number, process, operations, member, element, and/or a group of those, but do not mean exclusion of or denial of addition of another shape, number, process, operation, element, and/or a group of those.

Hereinbelow, embodiments of the present disclosure will be described in detail with reference to accompanying drawings.

FIG. 1 is a view showing a conventional vortex tube in contrast to the present disclosure. Furthermore, FIG. 1 is a comparative example in contrast to the embodiments shown in FIGS. 2, 3, and 4 disclosed in the present disclosure.

Figures shown in the drawings represent an actual device produced and tested by the applicant in the drawings, and there is one generator 3000, and six generator wings 3010 are provided for a purpose of the generator. Each of six air intake grooves 3020 has a size of height of 0.3 and width of 0.5 mm. An entrance 305 of the cold air outlet has a diameter of 2.2 mm.

FIGS. 2 and 3 have a difference of having two generators (300 and 400) and a sleeve (500, 510) located between the two generators in comparison with FIG. 1. In case of the generator wings 301, 401 provided for the generator to be serve as the generator, the first generator 300 has three generator wings 301 and the second generator 400 has three generator wings 401.

In case of air intake grooves 302, 402 formed between the generator wings 301, 401, the first generator 300, 310 has three air intake grooves 302, and the second generators 400 has three air intake grooves 402. Each of the air intake grooves 302, 402 has the same size of height of 0.3 and width of 0.5 mm as the air intake grooves provided in the vortex tube shown in FIG. 1.

The reason for limiting the numerical value of the vortex tube as described above is to accurately compare an effect by testing the vortex tube of the present disclosure in the same state as the related art shown in FIG. 1. However, in actual industrial application, those skilled in the art may change the number, size, etc. as much as needed on the basis of the operating principle of the vortex tube.

The reason, the number of the air intake grooves in FIG. 1 is six; FIGS. 2 and 3 respectively have the total six air intake grooves; and all the air intake grooves have the same size, is to control the volume of compressed air, so that the same volume of the compressed air supplied to operate and measure the vortex tube in the same condition. In this way, the effect of the invention shown in FIGS. 2 and 3 may be objectively measured. In FIGS. 1 to 3, the entrance of the cold air outlet has a diameter of 2.2 m.

A thickness of the sleeve 510 in FIG. 2 is not a sensitive problem. However, a diameter of a sleeve entrance 505 and a diameter of a sleeve outlet 507 are the same. Therefore, it is preferable that a rapid rotating wind diameter 307 of the first generator 300 has the same diameter as the diameter of the sleeve entrance 505. In FIG. 2, the diameter of the sleeve entrance 505 is 4.5 mm.

In FIG. 3, a thickness of the sleeve 500 affects the inclination of an inclined portion of the sleeve so as to affect the effectiveness of the vortex tube. Therefore, those skilled in the art may change the number, size, etc. as needed on the basis of the operating principle of the vortex tube. In the embodiment shown in FIG. 3, the sleeve with a thickness of 2 mm is used.

A point in the above configuration is the relationship between a diameter of an entrance 305 of a cold air outlet, an inner diameter of a cold and heat separation chamber 210, diameters of the sleeve entrance 505 and the sleeve outlet 507. It is preferable that the rapid rotating wind diameter 307 of the first generator 300 may be slightly different from the diameter of the sleeve entrance 505, but be equal to the diameter of the sleeve entrance 505.

The diameter of the sleeve entrance 505 may be changed as needed, but the diameter thereof is fundamentally formed equal to or larger than the diameter of the sleeve outlet 507. In addition, the diameter of the sleeve outlet 507 is fundamentally formed larger than the diameter than the diameter of the entrance 305 of the cold air outlet and smaller than the inner diameter of the cold and heat separation chamber 210.

The diameter of the sleeve outlet 507 may be changed as needed on the premise that the first generator 300, 320 and the second generator 400 generate rapid rotating wind on the basis of a value obtained by adding the diameter of the entrance 305 of the cold air outlet and the inner diameter of the cold and heat separation chamber 210 and dividing the sum by 2 to allow the flow in a direction of the cold and heat separation chamber 210 to be efficiently performed.

Whether or not the first generator 300, 320 and the second generator 400 generate the rapid rotating wind to efficiently perform the flow in the direction of the cold and heat separation chamber is significantly affected by the air intake grooves 302, 402 and a value of obtained by subtracting the diameter of the entrance 305 of the cold air outlet from the inner diameter of the cold and heat separation chamber 210.

The size of the air intake grooves 302, 402 is small and the value obtained by subtracting the diameter of the entrance 305 of the cold air outlet from the inner diameter of the cold and heat separation chamber 210 is large. Therefore, the diameter of the sleeve outlet 507 may further deviate from the value optioned by adding the diameter of the entrance 305 of the cold air outlet to the inner diameter of the cold and heat separation chamber 210 and dividing the sum by 2.

Those skilled in the art can determine an appropriate value of the diameter of the sleeve outlet 507 through repeatedly experiments by recognizing the principle of operation of the present disclosure.

Generally, it is preferable that the diameter of the sleeve outlet 507 satisfies [the diameter of the entrance of the cold air outlet+{(the inner diameter of the cold and heat separation chamber−the diameter of the entrance of the cold air outlet)/2±(the inner diameter of the cold and heat separation chamber−the diameter of the entrance of the cold air outlet)/4}].

FIG. 4 is a view showing the vortex tube shown in FIG. 3, wherein an outer tube cover 700 surrounding the cold and heat separation chamber 210 causes an effect that the compressed air flowing into the vortex tube through a compressed air inlet 110 cools the cold and heat separation chamber 210 with high temperature. Furthermore, a hot air adjusting valve 230 with a different shape is shown in the drawing.

Hereinbelow, the derivation of a comparative example and embodiments will be described.

The vortex tubes shown in FIGS. 1 to 3 are tested and compared to each other under the same conditions. The specifications of the manufactured vortex tubes are as shown in FIGS. 1 to 3, and metal used in the vortex tubes is SUS 316L.

The thickness of the sleeve is 2 mm and diameters of the sleeve entrance 505 and the sleeve outlet 507 in FIG. 2 are 4.5 mm. The diameter of the sleeve entrance 505 in FIG. 3 is 7 mm and the diameter of the sleeve outlet 507 is 4.5 mm. The compressed air supplied into the vortex tubes is controlled to remain at 7 bar continuously.

Experiments were conducted 5 times each by dividing the cold ratio into five stages of 30%, 32%, 34%, 36%, 38%, and 40%. Between the experiments, the temperature of the vortex tube was lowered to 15° C. by forcibly cooling so that following experiments were started in a stable state.

As a result of the experiment, discharge temperature at a cold side is measured, and the measurement time was determined in consideration that the temperature reaches a steady state in 1 minute, and cold discharge temperatures, which appear in exactly 3 minutes and 4 minutes after the compressed air supply time, was measured and averaged. In the experiment, the compressed air supplied in the vortex tube is controlled to generate the rapid rotating wind (cyclone) of 1,200,000 RPM.

As a result of the measurement, it was found that the vortex tube with the two generators as shown in FIGS. 2 and 3 is more efficient than the conventional vortex tube in FIG. 1. The reason of the above result is estimated as follows. For example, when 100% of compressed air generates the rapid rotating wind from one generator, a large volume of the compressed air is naturally moved forward along an outside an outer portion of an inside surface of the cold and heat separation chamber 210.

However, a large volume of the compressed air may be absorbed into a cold vortex flowing through a center portion of the cold and heat separation chamber 210 to the entrance of the cold air outlet.

Accordingly, when the vortex tube includes the two generators, a volume of the compressed air supplied into the first generator 300, 310 is a half of the total volume of the compressed air. A volume of a portion of the rapid rotating wind generated by the first generator 300, 310, the portion being absorbed in the cold vortex returned to the entrance 305 of the cold air outlet (volume that is population parameter, actually, is a value of multiplying population parameter by absorption rate) may be theoretically reduced to 50% of the total volume.

When the sleeve is inclined, the rapid rotating wind generated from the first generator 300, 310 is discharged through the sleeve without loss and is moved to the cold and heat separation chamber 210.

Under the above condition, 50% of the compressed air supplied through the compressed air inlet generates the rapid rotating wind through the second generator 400. The rapid rotating wind is generated by the first generator 300, 310 and is located at an outer portion of the rapid rotating wind that has a slightly reduced diameter while passing through the inclined sleeve. Accordingly, 100% of the rapid rotating wind may be moved toward the cold and heat separation chamber without contact with the cold vortex.

Therefore, the vortex tube with the two generators of the present disclosure may be considered to generate cold air colder than the vortex tube with the single generator. Of course, the diameter of the sleeve outlet 507 is larger than the diameter of the entrance 305 of the cold air outlet. Conventionally, it is preferable that the diameter of the sleeve outlet 507 is a value equal to ½ of the sum of the inner diameter of the cold and heat separation chamber 210 and the diameter of the entrance 305 of the cold air outlet.

According to the present disclosure, the inner diameter of the cold and heat separation chamber 210 is 7 mm and the diameter of the entrance 305 of the cold air outlet is 2.2 mm. Therefore, 4.6 mm is suitable as the diameter of the sleeve outlet 507, but the vortex tube may be sufficiently operated with the diameter from 4.1 to 5.1 m. The vortex tube of the present disclosure adopts the diameter of 4.5 mm at the sleeve outlet 507.

TABLE 1
[Comparative Example] Result of measurement
of conventional product shown in FIG. 1
(measure: ° C.)
Classification	30%	32%	34%	36%	38%	40%	Average
Cold	Run 1	−34.2	−33.8	−32.9	−32.4	−31.2	−30.4
discharge	Run 2	−35.2	−34.4	−33.3	−32.9	−30.8	−30.9
temper-	Run 3	−33.8	−33.5	−33.7	−31.9	−30.5	−29.6
ature	Run 4	−34.9	−32.9	−32.4	−32.8	−31.9	−31.1
	Run 5	−35.4	−34.8	−33.8	−31.4	−31.4	−30.2
Deviation	1.6	1.9	1.4	1.4	1.3	1.5	1.5
Average	−34.7	−33.9	−33.2	−32.3	−31.2	−30.4	−32.6

TABLE 2
[Embodiment 1] Result of measurement of product
of present disclosure shown in FIG. 2
(measure: ° C.)
Classification	30%	32%	34%	36%	38%	40%	Average
Cold	Run 1	−36.5	−36.0	−35.8	−34.2	−32.7	−31.8
discharge	Run 2	−37.2	−34.5	−35.1	−33.7	−31.8	−31.2
temper-	Run 3	−34.9	−36.7	−34.1	−32.2	−33.3	−30.1
ature	Run 4	−36.9	−35.3	−33.6	−34.9	−31.9	−32.1
	Run 5	−37.3	−35.9	−34.7	−32.9	−32.4	−31.5
Deviation	2.4	2.2	2.2	2.7	1.5	2.0	2.2
Average	−36.6	−35.7	−34.7	−33.6	−32.4	−1.3	−34.1

TABLE 3
[Embodiment 2] Result of measurement of product
of present disclosure shown in FIG. 3
(measure: ° C.)
Classification	30%	32%	34%	36%	38%	40%	Average
Cold	Run 1	−38.5	−37.9	−37.5	−36.5	−35.2	−33.4
discharge	Run 2	−39.7	−38.8	−36.9	−35.1	−34.1	−32.1
temper-	Run 3	−37.5	−37.2	−38.2	−36.8	−35.5	−33.8
ature	Run 4	−40.3	−38.4	−36.4	−35.4	−33.9	−33.1
	Run 5	−38.8	−38.1	−37.4	−36.2	−34.9	−32.5
Deviation	2.8	1.6	1.8	1.7	1.6	1.7
Average	−39.0	−38.1	−37.2	−36.0	−34.7	−33.0	−36.3

FIG. 6 is a view showing a vortex tube with three generators by adding one generator to the vortex tube in FIG. 3.

The first generator and the second generator in FIG. 6 are designed with the same structure as the first generator and the second generator of the vortex tube in FIG. 3. The third generator in FIG. 6 is manufactured to have three wings and three air intake grooves of the same size like the vortex tube in FIG. 3. Other numerical values are as shown in

FIG. 5. Therefore, the vortex tube in FIG. 6 has nine air intake grooves, so the compressed air is supplied 41 to 43% more than the vortex tube in FIGS. 1 to 3.

TABLE 4
[Embodiment 3] Result of measurement of product
of present disclosure shown in FIG. 6
(measure: ° C.)
Classification	30%	32%	34%	36%	38%	40%	Average
Cold	Run 1	−35.5	−35.8	−35.1	−33.8	−32.2	−31.2
discharge	Run 2	−37.2	−33.9	−34.8	−32.9	−31.5	−30.5
temper-	Run 3	−34.8	−36.2	−34.1	−34.1	−32.9	−29.9
ature	Run 4	−36.1	−35.6	−33.4	−34.5	−33.0	−32.0
	Run 5	−36.7	−35.4	−34.4	−32.6	−32.3	−31.3
Deviation	2.4	2.3	1.7	1.9	1.5	2.1	2.0
Average	−36.1	−35.4	−34.4	−33.6	−32.4	−31.0	−33.8

FIG. 7 is a view showing an embodiment in which a counterflow prevention cap 150 is inserted in the hot air adjusting valve so that the vortex tube may be operated even under external pressure. The counterflow prevention cap 150 is generally made of synthetic resin containing rubber properties, but may be made of metal with elasticity. The counterflow prevention cap 150 does not act as a resistor when heat is discharged to the outside of the vortex tube, but when the outside air flows into the inside of the vortex tube, the counterflow prevention cap 150 spreads to serve as the resistor.

Although a preferred embodiment of the present disclosure has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the present disclosure as disclosed in the accompanying claims.

Claims

1. A vortex tube comprising:

a cold and heat separation chamber;

a cold air outlet provided at an end of the cold and heat separation chamber;

a generator provided between the cold air outlet and the cold and heat separation chamber;

a hot air outlet provided at another end of the cold and heat separation chamber and including a hot air adjusting valve; and

an outer tube cover comprising a compressed air inlet and surrounding the cold and heat separation chamber at a predetermined gap while blocking the cold and heat separation chamber at an outside thereof, so that introduced compressed air can be supplied into the generator,

wherein the compressed air flowing through the compressed air inlet generates rapid rotating wind by passing through the generator to be moved into the cold and heat separation chamber to separate cold and heat from each other.

2. The vortex tube of claim 1, wherein a counterflow prevention cap is inserted in the hot air outlet including the hot air adjusting valve.

3. A vortex tube comprising:

a cold and heat separation chamber;

a cold air outlet provided at an end of the cold and heat separation chamber;

a first generator, a sleeve, and a second generator provided between the cold air outlet and the cold and heat separation chamber;

a compressed air inlet provided at a portion close to the first generator and the second generator and configured to supply compressed air into the first generator and the second generator; and

a hot air outlet provided at another end of the cold and heat separation chamber and including a hot air adjusting valve,

wherein an outlet of the sleeve has a diameter larger than a diameter of an entrance of the cold air outlet and smaller than an inner diameter of each of the generators.

4. The vortex tube of claim 3, wherein the sleeve is inclined such that an entrance of the sleeve has a diameter larger than the diameter of the outlet of the sleeve.

5. The vortex tube of claim 3, wherein a diameter of an entrance of the sleeve coincides with the inner diameter of the first generator.

6. The vortex tube of claim 5, wherein the diameter of the outlet of the sleeve satisfies the following equation.

[diameter of entrance of cold air outlet+{(inner diameter of cold and heat separation chamber−diameter of entrance of cold air outlet)/2±(inner diameter of cold and heat separation chamber−diameter of entrance of cold air outlet)/4}]

7. The vortex tube of claim 3, further comprising:

a third generator in addition to the second generator.

8. The vortex tube of claim 7, further comprising:

a second sleeve in which the third generator is provided, wherein a passage in the second sleeve is inclined such that an entrance of the second sleeve has a diameter larger than a diameter of an outlet thereof.