EP0990464B1 - Jet pump for compression of a two phase mixture by means of supersonic flow - Google Patents

Abstract

The process comprises forming a foam (21) from the gas and a liquid, where the speed of sound is smaller than the in gas and in the liquid ; directing the foam at supersonic speed through a nozzle (19,20) so condensing the gas; and separating the condensed gas and liquid from one another after the nozzle (19,20). An Independent claim is included for a condensing apparatus (10).

Description

TECHNICAL AREA

The present invention relates to the field of compressor technology. she relates to a method for compressing a gas and a compression device to perform the procedure.

STATE OF THE ART

In the prior art (see e.g. the document US-A-5,083,429) is already different has been proposed to create a flowing gaseous medium to compress it in a suitable device (compression tube) first accelerated to supersonic speed and then generating shock waves and then increasing the pressure again is braked. The heat generated during the compression can, for example by injecting water into the corresponding pipe section be dissipated. The disadvantage of this type of compression is that the speed of sound the gaseous medium (e.g. air) is usually relatively high, and that therefore some effort must be made to keep the gas flow going Bring supersonic speed.

PRESENTATION OF THE INVENTION

It is therefore an object of the invention to provide a method and an apparatus for the Specify compression of a gaseous medium, which with a clear work at reduced speed of sound and therefore with less effort can be realized.

The object is achieved in a method of the type mentioned at the outset by that in a first step a foam from the gas and a liquid is formed in which the speed of sound is significantly lower than that Gas and in the liquid taken that in a second step the Foam passed through a nozzle at supersonic speed and thereby the gas in the foam is compressed, and that in a third step behind the nozzle the compressed gas and the liquid are separated become.

Advantageous further developments of the method according to the invention are the subject of dependent claims 2 to 9.

The essence of the invention is a foam-like for compression Gas-liquid system to use, which is opposed by one the significantly reduced speed of sound in the individual components. This makes it possible for the compression process with reduced effort to achieve the necessary supersonic speed. At the same time can over the liquid that is separated again later on is the one that arises during compression Heat can be dissipated easily.

A preferred embodiment of the method according to the invention is thereby characterized in that a substantially still foam is generated that the nozzle is moved through the foam at supersonic speed, and that the movement of the nozzle is carried out as a circular movement around an axis of rotation becomes. This type of procedure proves to be particularly favorable for the Implementation of the method by apparatus.

A preferred development of this embodiment because of its simplicity is characterized in that the foam behind the nozzle in one with the Nozzle with the moving collecting container is caught, and that when rotating centrifugal force arising in the collecting container for the separation of gas and Liquid is used.

Another preferred embodiment of the method according to the invention is characterized in that to produce the foam, the gas in one volume the liquid is introduced distributed and that the gas from below through a porous bottom into a layer of liquid above the bottom is introduced. This makes it possible to create a fine-pored surface over a large area without moving parts Generate foam that is special for the compression according to the invention suitable is.

The compression device according to the invention for performing the method according to the invention is characterized by a container for the generated Foam, which container with first means for generating the foam is connected, and at least one nozzle, which is relative to the foam The foam can be moved through the nozzle at supersonic speed passes, and second means for separating the foam into gas and Liquid, which second means are arranged behind the nozzle.

Advantageous further developments of the compression device according to the invention are the subject of dependent claims 11 to 16.

A first preferred embodiment of the device according to the invention is characterized in that the first means comprise a porous floor, which closes the container down, and which from the bottom The gas can be acted on over a wide area such that the at least one nozzle is located inside of the container on an arm rotatable about a central axis of rotation and essentially is arranged tangentially to the rotating circle that the arm of a motor is driven that the second means each installed one behind the nozzle and connected to the nozzle collection container, which each on End of the arm is arranged, and that in the collecting container third Means for separate removal of the gaseous particles which separate during the rotation and liquid components are provided.

A preferred development of this embodiment is characterized in that that the arm is each tubular, that the third means each include first inner tube extending within the arm, and that the Liquid through the first inner tube and the gas in the space between the first inner tube and the arm.

BRIEF EXPLANATION OF THE FIGURES

Fig. 1

ein Diagramm der Abhängigkeit der Schallgeschwindigkeit in einem Luft-Wasser-System vom Verhältnis ε des Luftvolumens V_air zum Gesamtvolumen V des Luft-Wasser-Gemisches;

Fig. 2

in der Draufsicht ein bevorzugtes Ausführungsbeispiel einer Kompressionsvorrichtung mit zwei Düsen an zwei Armen; und

Fig. 3

die Kompressionsvorrichtung nach Fig. 2 in der teilweise geschnittenen Seitenansicht.

The invention will be explained in more detail below on the basis of exemplary embodiments in connection with the drawing. Show it

Fig. 1

a diagram of the dependence of the speed of sound in an air-water system on the ratio ε of the air volume V _air to the total volume V of the air-water mixture;

Fig. 2

in plan view a preferred embodiment of a compression device with two nozzles on two arms; and

Fig. 3

2 in the partially sectioned side view.

WAYS OF CARRYING OUT THE INVENTION

An essential feature of the present invention is the use of a Gas-liquid system for compression of the gas itself. In two-phase Gas-liquid flows are often the speed of sound is much lower than the speed of sound of the pure gas or liquid. So e.g. the speed of sound below 40 m / s in an air-water system, if the volume ratio ε of air to the mixture as a whole between 0.1 and 0.9 (Fig. 1). This means that supersonic speed is relative simply generated and that such a mixture through a flow cross-sectional constriction can be highly compressed.

A special form of such a gas-liquid or air-water mixture is the foam. Foam is characterized by high gas or air volume fractions (ε ≈ 0.9). Foam is defined as a dispersion of gas in a liquid, which contains one or more surface-active substances. The liquid is lying mainly in the form of thin films to coat the foam Bubbles before. The size (diameter) of the bubbles varies between a few micrometers (fine foam) and several millimeters (coarse foam). The surface-active substances are soluble in the liquid and reduce their surface tension, so that the formation of stable bubbles allows becomes. In the exemplary air-water mixture, for example, foam by means of a 1-5% butyl glycol / water solution and air.

The method according to the invention can now be done by means of a compression device of which a preferred exemplary embodiment is shown in FIG. 2 and 3 is reproduced. The compression device 10 shown comprises a container 11 in which the desired foam 21 is generated. The container 11 is closed at the bottom by a porous bottom 23, over a layer during the operation of the compression device 10 the liquid 22 used (in particular water plus surface-active Substances). A feed space 24 is arranged below the porous base 23, the via a feed 25 with the used to be compressed Gas (especially air) can be filled. The gas penetrates in the form of small bubbles from the feed chamber 24 through the porous bottom 23 - which also as a perforated plate or the like. Can be formed - in the liquid 22 above and generated when passing through the liquid 22, the foam 21, the container 11 fills more or less strongly above the liquid 22.

In the area of the foam 21 there is a central one inside the container 11 Rotation axis 12 rotatably arranged a system which by means of a motor 26 (or an equivalent drive) moved at a peripheral speed is, which is above the speed of sound of the foam 21, and with this Ultrasound speed captures the foam 21 and by reducing the cross-section flows. This is done on two opposite arms 15, 16 two tangentially directed nozzles 19, 20 are provided, through which the relative flows to the foam 21 at rest, rotating around the axis of rotation 12, nozzles 19, 20 and arrives in the collecting container 17, 18 located behind it. It understands It goes without saying that instead of the two nozzles 19, 20 shown in the example only one nozzle or more than two nozzles can be used.

In the receptacles 17, 18 one ends in front of the container wall of the tubular arm 15, 16 concentrically extending inner tube 29, 30. Die radial inner tubes 29, 30 are to an axial lying in the axis of rotation 12 Inner tube 14 guided and connected to this. The tubular arms 15, 16, connect the receptacles 17, 18 with an axial outer tube 13, which surrounds the axial inner tube 14 concentrically. The axial tubes 13, 14 serve as Wave. You and the arms 15, 16 attached to them are by the below of the container 11 arranged motor 26 rotated. The axial tubes 13, 14 are closed down too. From the outside, they are suitable from the outside Outlets 27, 28 accessible.

The compression device 10 shown in FIGS. 2 and 3 now works as follows: Rotate in the container filled with foam 21 - driven by the engine 26 - the two nozzles 19, 20 with the associated collecting container 17, 18 counterclockwise (rotating arrows in Fig. 2). The speed of rotation in the exemplary and preferred air-water mixture is approx. 100 m / s, i.e. the nozzles 19, 20 move relative to the foam 21 at supersonic speed. Such a speed can be achieved, for example when the rotational frequency of the motor 26 is 50 Hz and the nozzles 19, 20 have a distance of approximately 0.3 m from the axis of rotation 12.

The two-phase mixture is compressed in the nozzles 19, 20. In the Collection containers 17, 18 behind the nozzles 19, 20, the liquid (water) thrown radially outwards due to the centrifugal force and over the radial inner tubes 29, 30 and the axial inner tube 14 transported to the outlet 28. The liquid emerging at outlet 28 can - possibly after heat has been removed - are returned to the container 11 for foam formation. The gas (air) remaining during ejection is in the space between the arms 15, 16 and the radial inner tubes 29, 30 to the axial outer tube 13 out and can (in compressed form) removed at the outlet 27 become.

As already mentioned above, the bottom 23 of the container 11 consists of a porous material or a perforated plate. Is on the floor 23 always a layer of liquid 22. The gas (air) flows through the bottom 23 and forms 22 bubbles when penetrating the liquid layer. It is created this way always a fresh foam 21.

With initial volume ratios of ε = 0.9 (with air-water mixture) the mass ratio of water to air 85.9, i.e. that during compression The heat released from the air is absorbed by the water without it there is a significant temperature increase.

LIST OF REFERENCE NUMBERS

10

compression device

11

container

12

axis of rotation

13

outer tube

14

inner tube

15.16

poor

17.18

receptacle

19.20

jet

21

foam

22

Liquid (liquid layer)

23

Floor (porous)

24

Feed space (gas)

25

Supply (gas)

26

engine

27

Outlet (gas)

28

Outlet (liquid)

29.30

inner tube

Claims (16)

1. Method of compressing a gas, characterized in that, in a first step, a foam (21) is formed from the gas and a liquid, in which foam (21) the sonic velocity is markedly lower than in the gas and in the liquid taken by themselves, in that, in a second step, the foam is directed at supersonic velocity through a nozzle (19, 20) and the gas located in the foam is thereby compressed, and in that, in a third step, the compressed gas and the liquid are separated from one another behind the nozzle (19, 20).
2. Method according to Claim 1, characterized in that an essentially static foam (21) is produced, and in that the nozzle (19, 20) is moved at supersonic velocity through the foam (21).
3. Method according to Claim 2, characterized in that the movement of the nozzle (19, 20) is executed as a circular movement about an axis of rotation (12).
4. Method according to Claim 3, characterized in that the foam is collected behind the nozzle (19, 20) in a collecting container (17, 28) moving along with the nozzle (19, 20), and in that the centrifugal force arising in the collecting container (17, 18) during the rotation is used for the separation of gas and liquid.
5. Method according to one of Claims 1 to 4, characterized in that, to produce the foam (21), the gas is introduced into a volume of the liquid (22) in a distributed manner.
6. Method according to Claim 5, characterized in that the gas is introduced from below through a porous base (23) into a layer of the liquid (22) above the base (23).
7. Method according to one of Claims 1 to 6, characterized in that, to stabilize the foam, at least one surface-active substance is admixed with the liquid (22) before the formation of the foam.
8. Method according to one of Claims 1 to 7, characterized in that air is compressed, and wherein the liquid (22) used is water.
9. Method according to Claim 8, characterized in that butyl-glycol, in particular with the formation of a 1 to 5% solution, is added as a surface-active substance to the water.
10. Compression apparatus (10) for carrying out the method according to Claims 1 to 9, characterized by a container (11) for the foam (21) produced, which container (11) is connected to first means (22-25) for producing the foam (21), as well as at least one nozzle (19, 20), which can be moved relative to the foam in such a way that the foam (21) passes at supersonic velocity through the nozzle (19, 20), as well as second means (17, 18; 29, 30) for the separation of the foam into gas and liquid, which second means are arranged behind the nozzle (19, 20).
11. Compression apparatus according to Claim 10, characterized in that the first means comprise a porous base (23), which closes off the container (11) at the bottom and to which gas can be admitted over the surface area from the underside.
12. Compression apparatus according to either of Claims 10 and 11, characterized in that the at least one nozzle (19, 20) is arranged inside the container (11) on an arm (15, 16) so as to be rotatable about a central axis of rotation (12) and essentially tangentially to the circle of rotation, and in that the arm (15, 16) is driven by a motor (26).
13. Compression apparatus according to Claim 12, characterized in that the second means in each case comprise a collecting container (17, 18), which is attached behind the nozzle (19, 20), is connected to the nozzle (19, 20) and is in each case arranged on the end of the arm (15, 16), and in that in each case third means (29, 30) for the separate discharge of the gaseous and liquid components separating during the rotation are provided in the collecting container (17, 18).
14. Compression apparatus according to Claim 13, in that the arm (15, 16) is in each case of tubular design, in that the third means comprise a first inner tube (29, 30) running in each case inside the arm (15, 16), and in that the liquid is drawn off through the first inner tube (29, 30) and the gas is drawn off in the intermediate space between the first inner tube (29, 30) and the arm (15, 16).
15. Compression apparatus according to Claim 14, characterized in that an outer tube (13) and a second inner tube (14), through which the gas and respectively the liquid are directed out of the container (11) after their separation, are arranged concentrically in the axis of rotation (12), and in that the arm (15, 16) is in each case connected to the outer tube (13) and the first inner tube (29, 30) is in each case connected to the second inner tube (14).
16. Compression apparatus according to one of Claims 12 to 15, characterized in that a plurality of nozzles (19, 20), distributed over the circumference, are arranged so as to be rotatable inside the container (11) on corresponding arms (15, 16) and are driven by the motor (26).

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