DE3401993A1 - Cooling device - Google Patents

Abstract

A cooling device which utilises the Joule-Thomson effect and has a substrate element 4 which supports the object to be cooled has a sleeve 6 in which a capillary tube 1 provided with fins is arranged. Vortex-producing means are provided in order to cause the flow medium, which emerges through outlet openings 3,3' of the pipe 1, to be swirled over the surface of the substrate. The flow medium can be caused to form vortices in that the openings 3,3' are oriented such that the flow medium emerges tangentially. <IMAGE>

Description

The invention relates to a cooling device, which is a source of pressurized gas, for example argon or Uses air and works on the basis of the Joule Thomson effect to achieve a low absolute temperature produce.

The Joule Thomson effect is defined as the change in temperature of a gas that passes through an orifice is expanded, for example an opening or a porous plug is fed to the high pressure, and by the gas is expanded to low pressure.

In a known cooling device is a metal pipe, which acts as a heat exchanger, wound on a molded body and one end to a pressure medium source while an opening is provided at the other end through which the fluid is blown to produce a cooling effect. In operation, the fluid is blown out through the opening so that that it strikes perpendicularly to the surface of the substrate at a point that is that point opposite to which the object to be cooled is attached is, for example, an infrared detector. After the fluid impinges on the substrate, the expelled cooled fluid caused to flow back over the coils of the tube, thereby releasing the pressurized fluid is precooled upstream of the opening, which results in a regenerative effect that the Temperature of the discharged fluid noticeable lowers. In the known cooling devices, the working medium is usually argon or air and it has

it has been shown that after only a short period of work the cooling and regenerative effects of the Vorrichtunq have the consequence that the gas liquefies upstream of the opening.

In the known state of the art, one seeks to make the substrate as small as possible, in such a way that that its small surface area limits the cooling effect, both in terms of cooling time and with regard to the minimum continuous temperature reached. Because the fluid is normally on the surface of the substrate, its velocity is reduced considerably and this causes the temperature increases near the central region of the substrate.

According to the invention, the object of improved cooling in a cooling device of the generic type is achieved in that it has a substrate element, ^{x to} carry an object, that a continuously extending wall attaches sealingly to a surface of the substrate element around a vortex chamber to provide that means for producing the Joule Thomson effect are provided which comprises a channel which is at least partially enclosed within the continuous wall and which is connected at one end to a source of pressurized fluid and at the other end has openings but which are adjacent are arranged at a distance from the one surface of the substrate in order to blow out the fluid into the chamber, and that the openings are arranged and designed in such a way that the escaping fluid

34CT993

is swirled in the chamber.

The openings are preferably opposite the substrate element oriented so that the fluid exits generally tangentially.

Expediently, there are two openings in one end area of the channel arranged at a distance from one another opposite side regions of the substrate, wherein the Fluid is blown out of the two openings in opposite, generally tangential directions will.

A sleeve is expediently arranged in a sealing manner around the circumference of the substrate element.

In this case, the edge areas of the substrate and the peripheral wall is provided with a metal plating to improve the heat transfer between them.

According to a further feature of the invention, the object set is achieved in that it is a substrate element for holding an object has that a sleeve sealingly on a surface of the substrate element is attached that a shaped body is arranged within the sleeve that the channel is helical between the molded body and the sleeve extends that the channel with one end to a DruckströmunqsmittelquelIe is connected and has openings to the fluid in the area between to blow out the substrate element and the adjoining end of the shaped body and cause vortex generators,

that the fluid emerging from the openings is entwined over the surface of the substrate element.

Embodiments of the invention are shown below described with reference to the drawing. Mark in the drawing:

1 shows a schematic side view of a known cooling device;

Fig. 2 is a schematic side view of one designed according to the invention Cooling device.

According to FIG. 1, the known cooling device has a ribbed capillary tube 1 wound on a cylindrical support 2, wherein one end of the tube is connected to a pressurized gas source, not shown, while the other Has a single opening 3 at the end. The tube 1 and the cylindrical shaped body 2 are surrounded by a sleeve 6 enclosed, which is sealingly connected to a substrate disc made of thermally conductive material, for example made of sapphire or aluminum oxide. The sleeve is made of a metal with low conductivity an expansion coefficient equal to that of the substrate wafer is adapted. The object to be cooled is usually in the center of the outer surface of the Substrate disc 4 housed. In this embodiment of the cooling device, it hits from the opening

exiting fluid jet normally on the center of the inner surface of the substrate wafer 4. As mentioned above, however, the temperature of the fluid increase in that area, since the Fluid velocity decreased considerably depending on the direction of impact. That area usually coincides with the area where the object to be cooled is located.

Reference is now made to FIG. In this cooling device according to the invention, there is again a capillary tube 1 provided with ribs wound onto a molded body 2. The right end of the pipe (on the right according to FIG. 2) has two openings 3, 3 'which are spaced apart from one another and which in the typical case 0.05 mm (0.002 inches) in diameter and over spaced side panels the substrate wafer 4 come to rest and are oriented so that they the fluid in blow out opposite tangential directions over the substrate 4, so that the exiting from the tube 1 Fluid swirls over the inner surface of the substrate wafer 4 about an axis is offset, which coincides with the longitudinal axis of the sleeve 6. Adjacent peripheral areas of the Substrate wafer 4 and the sleeve 3 are with a continuous Metal coating 7, e.g. made of silver, is provided to prevent heat transfer between the substrate and the end of the tube 6 to improve. The coating 7 formed by the metal plating can be arranged outside as shown in the drawing, but instead and / or in addition to

the inside can be applied by electroplating.

The object to be cooled can be manufactured separately and in the middle on the outer surface of the Substrate wafer 4 are fixed by a suitable adhesive. For special applications however, the substrate itself forms part of the object to be cooled.

It is believed that the turbulence of the fluid exiting from the openings 3, 3 ^1, an improved cooling for the following reasons effects: First, it is the fluid with the substrate element longer in contact in comparison with a configuration in which it strikes the substrate perpendicularly, resulting in a greater mass flow over the substrate! Second, it is assumed that the coolant can reach the corner regions between the sleeve 6 and the substrate 4. This is an advantage since a significant amount of the cooling of the substrate takes place via the end of the sleeve 6, and accordingly this advantage is achieved by the cladding 7. In addition, the movement of the fluid creates a vortex in which the lowest temperature occurs in the vicinity of its center and since this coincides with the point at which the object to be cooled comes to rest, there is improved cooling.

AO

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Claims (5)

Patent Attorneys .-; :::: Öi.p1: -Ing. C urt Wallach ··· u _n * *. *,. Dipl.-Ing. Günther Koch European patent agent ^ ^β " ₄ . . “Dipl.-Phys. Dr Tino Haibach European Patent Attorneys ^K ' Dipl.-Ing. Rainer Feldkamp D-8000 Munich 2 Kaufingerstraße 8 Telephone (0 89) 2 60 80 78 Telex 5 29 513 wakai d Date: ^{January 20} , 1984 Our reference: 17 849 - K / Ap British Aerospace
Public Limited Company
100, Pall Mall
London, SW1Y 5HR
England Cooling device
Patent claims: Cooling device for cooling an object, characterized in that it comprises a substrate element (4) for an object wear that a continuously extending wall (6) sealingly on a surface of the Substrate element (4) attaches to create a vortex chamber that means for generating the Joule Thomson effect are provided, which have a channel (1) which is at least partially is enclosed within the continuous wall (6) and at one end with a pressurized fluid source is connected and at the other end openings (3,3 ') carries, which are arranged adjacent but at a distance from one surface of the substrate (4) are to blow the fluid into the chamber, and that the openings (3,3 ') such are arranged and designed so that the exiting fluid swirls in the chamber will. 2. Cooling device according to claim 1, characterized in that the openings (3, 3 ') are arranged opposite the substrate element (4) so that the fluid exits substantially tangentially, causing the exiting Fluid is swirled in the swirl chamber. 3. Cooling device according to claims 1 or 2, characterized in that the openings of two openings (3, 3 ') are formed, which are arranged in an end region of the channel (1) and are distributed at a distance over the lateral regions of the substrate element (4), and that each orifice blows the fluid out in opposite generally tangential directions, thereby causing the blown fluid within the swirl chamber in Vortex movement is displaced. 4. Cooling device according to one of the preceding - Expectations, characterized in that the continuously extending wall (6) is arranged sealingly around the circumference of the substrate element (4). 5. Cooling device according to claim 4, characterized in that abutting corner regions of the substrate (4) and the continuous Wall (6) provided with a meta 11 coating (7) are to improve the heat transfer between them. Cooling device according to one of the claims 1 to 5, characterized in that it is a substrate element (4) for holding an object comprises that a sleeve (6) is sealingly attached to a surface of the substrate element (4) is that a molded body (2) is arranged within the sleeve (16) that the channel (1) is extends helically between the shaped body (2) and the sleeve (6) that the channel (10) one end connected to a source of pressurized fluid and ports (3,3 ') to the fluid in the area between the substrate element and the blow out adjacent end of the molded body and that vortex generators cause that from the fluid exiting the openings is swirled over the surface of the substrate element will .