GB1565982A - Vortex tubes - Google Patents

Description

(54) VORTEX TUBES (71) We, REDPOINT ASSOCIATES LIMITED a British Company of Lynton Road. Cheney Manor, Swindon SN2 2QN do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to vortex tubes.

A vortex tube is an apparatus which converts a moving stream of gas, usually air, into a hot stream and a cold stream by guiding the incoming gas into a vortex from which the gas moves into a tube of controlled length, cold gas being taken from one end of the tube at one side of the vortex and hot gas from the other end of the tube. Such apparatus is in principle well known.

An object of the present invention is to provide a vortex tube of improved construction which can be manufactured at a substantially lower cost than vortex tubes hitherto known.

The invention accordingly provides a vortex tube comprising a main body defining a cavity and a tube extending in one direction therefrom, said main body being formed as an integral plastics moulding; an inlet communicating with said cavity; a vortex generator positioned within said cavity to define with the main body an outer space for receiving pressurised gas and having an inner vortex chamber communicating by tangential passages in the vortex generator with said outer space; a cold outlet to the side of the vortex generator opposed to said tube; a hot outlet at the other end of the tube; and a valve adjustably positioned across the hot outlet.

It is also known to use a cruciform "brake" at the hot end of the tube, i.e. a member which subdivides the tube into a number of parallel flow passages. The most usual form of brake is a tube or strip formed into a Maltese cross configuration. In accordance with a preferred feature of the present invention, the brake is a simple plane member forming a tranverse division across the hot end of the tube.

Preferably also, the tube is formed in the direction from the vortex chamber as an initial divergent portion leading into a portion of constant cross-section.

An embodiment of the invention will now be described by way of example, with reference to the accompanying drawing, in which: Figure 1 is a longitudinal cross-section through a vortex tube embodying the invention; and Figure 2 is a section on the line 2-2 of Figure 1.

The vortex tube comprises a tube body 10, a vortex generator 12, a cold outlet 14, and a hot end valve 16. The cold outlet 14 and vortex generator 12 are positioned together by means of cooperating shoulders and are locked in position at the cold end of the tube body by means of a nut 20 baring on the cold outlet 14; the latter thus locates the vortex generator 12. An annular space 22 is defined between the radially outer surface of the vortex generator 12 and the inner surface of the tube body 10, and is delimited axially at one end by the cold outlet 14. Compressed air is supplied to the annular space 22 via an inlet 24, and passes from the annular space 22 into a generally cylindrical chamber 26 within the vortex generator 12 via tangential passages 28 in the vortex generator 12 to form a vortex.The vortex generator 12 and cold outlet 14 together define a bore 30 for passage of cold air. The remainder of the tube body 10 is formed internally with a divergent section 32 and a constantdiameter section 34. The use of a tapered section such as 32 permits a rapid expansion of the rotating vortex as it enters the hot tube, and allows the overall length of the tube to be shortened.

Hot air leaves the hot end of the tube via a bore 36 and an outlet 18, the degree of opening to the exterior of the tube being controlled by the position of the valve 16 which is screw threaded in the tube body 10 for positioning by means of a handle 38.

In accordance with the present invention, the entire tube body 10 including the inlet 24 and outlet 18, the portion receiving the vortex generator, the divergent section 32, and the constant-diameter section 34 is formed by a unitary plastics moulding. Preferably this member is produced from glass filled nylon by injection moulding.

A brake 40 is provided at the hot end of the tube 10. The brake 40 comprises a metal strip secured (e.g. by being a press fit) diametrically in the section 34, as may be seen in the end view of Figure 2.

In prior art vortex tubes of which we are aware, the tube body has been fabricated from metal, typically brass, with parts such as the inlet, hot outlet and valve holder secured to the main tube body by screwthreaded connection or by welding. The present invention thus permits a very substantial reduction in manufacturing costs.

The invention also provides a simplified and economical form of brake which has been found to operate with comparable efficiency to prior art brakes in reducing the overall tube length required for desired gas flows and temperature ratios.

WHAT WE CLAIM IS: 1. A vortex tube comprising a main body defining a cavity and a tube extending in one direction therefrom, said main body being formed as an intergal plastics moulding: an inlet communicating with said cavity; a vortex generator positioned within said cavity to define with the main body an outer space for receiving pressurised gas and having an inner vortex chamber communicating by tangential passages in the vortex generator with said outer space; a cold outlet to the side of the vortex generator opposed to said tube; a hot outlet at the other end of the tube; and a valve adjustably positioned across the hot outlet.

2. A vortex tube according to claim 1, in which said moulding is of glass-filled nylon.

3. A vortex tube according to claim 1 or 2, in which the inlet and the hot outlet are also formed integrally with said main body.

4. A vortex tube according to any preceding claim, in which the cold outlet comprises a body partially received within said cavity and delimiting one side of said outer space, the cold outlet body locating the vortex generator by means of interfitting formations on each.

5. A vortex tube according to any preceding claim, in which said tube is formed internally in the direction away from the vortex generator as a divergent section followed by a section of constant diameter.

6. A vortex tube according to any preceding claim, including a brake in the form of a plane member positioned diametrically across said tube adjacent the hot outlet.

7. A vortex tube substantially as hereinbefore described with reference to and as shown in the accompanying drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. hot tube, and allows the overall length of the tube to be shortened. Hot air leaves the hot end of the tube via a bore 36 and an outlet 18, the degree of opening to the exterior of the tube being controlled by the position of the valve 16 which is screw threaded in the tube body 10 for positioning by means of a handle 38. In accordance with the present invention, the entire tube body 10 including the inlet 24 and outlet 18, the portion receiving the vortex generator, the divergent section 32, and the constant-diameter section 34 is formed by a unitary plastics moulding. Preferably this member is produced from glass filled nylon by injection moulding. A brake 40 is provided at the hot end of the tube 10. The brake 40 comprises a metal strip secured (e.g. by being a press fit) diametrically in the section 34, as may be seen in the end view of Figure 2. In prior art vortex tubes of which we are aware, the tube body has been fabricated from metal, typically brass, with parts such as the inlet, hot outlet and valve holder secured to the main tube body by screwthreaded connection or by welding. The present invention thus permits a very substantial reduction in manufacturing costs. The invention also provides a simplified and economical form of brake which has been found to operate with comparable efficiency to prior art brakes in reducing the overall tube length required for desired gas flows and temperature ratios. WHAT WE CLAIM IS:

1. A vortex tube comprising a main body defining a cavity and a tube extending in one direction therefrom, said main body being formed as an intergal plastics moulding: an inlet communicating with said cavity; a vortex generator positioned within said cavity to define with the main body an outer space for receiving pressurised gas and having an inner vortex chamber communicating by tangential passages in the vortex generator with said outer space; a cold outlet to the side of the vortex generator opposed to said tube; a hot outlet at the other end of the tube; and a valve adjustably positioned across the hot outlet.

2. A vortex tube according to claim 1, in which said moulding is of glass-filled nylon.

3. A vortex tube according to claim 1 or 2, in which the inlet and the hot outlet are also formed integrally with said main body.

4. A vortex tube according to any preceding claim, in which the cold outlet comprises a body partially received within said cavity and delimiting one side of said outer space, the cold outlet body locating the vortex generator by means of interfitting formations on each.

5. A vortex tube according to any preceding claim, in which said tube is formed internally in the direction away from the vortex generator as a divergent section followed by a section of constant diameter.

6. A vortex tube according to any preceding claim, including a brake in the form of a plane member positioned diametrically across said tube adjacent the hot outlet.

7. A vortex tube substantially as hereinbefore described with reference to and as shown in the accompanying drawing.