Nozzle for introducing and metering a treatment medium into the exhaust gas stream in combustion processes

Abstract

The nozzle for introducing and for metered addition of a treatment medium into the exhaust gas stream in combustion processes comprises a nozzle tube (2) and an inner displacement body (1) having a round cross section to form a nozzle ring gap (14). The displacement body (1) borders a mixing chamber (18) inside the nozzle tube (2) and on this end has a tapered area (3) with which it is held exclusively on a feed tube (5) for the treatment medium. The feed tube (5) crosses through a pressure chamber (6.1), which has two axial bordering walls (4, 7). The feed tube is held in these bordering walls, with a holder (12) being provided in the bordering wall (4), allowing the carrier medium from the pressure chamber (6.1) to flow through to the nozzle gap (14).

Description

The present invention is explained in greater detail below on the basis of an exemplary embodiment. In the drawing are illustrated:

FIG. 1 a longitudinal section through a nozzle and

FIG. 2 an enlarged section of the front area of the nozzle according to FIG. 1.

As shown in the drawing, the nozzle has an outer casing element 2 and an inner displacement body 1 having a round cross section, having a length L2 and extending in to the casing element 2 over a length L1. In this way a nozzle gap 14 is bordered. The casing tube 4 is connected by means of a detachable connector 4.1, such as a nut, to a bordering wall 4.

The displacement body 1 has a tapered area 3 on its rear end with which it is connected to a feed element 5 for a treatment medium. This feed element 5 thus forms the holding device for the displacement body 1.

The feed element 5 is held in the bordering wall 4 of a pressure space 6.1 by means of a holder 12, which allows a carrier medium 11 to flow from the pressure space 6.1 to the nozzle gap 14. A rear bordering wall 7 of the pressure space 6.1 serves to hold the feed element 5. The pressure space 6.1 is bordered on its circumference by a tubular wall 6, which has an inlet opening 10 for a carrier medium 11.

Between the holder 12 and the bordering wall 4 and the tapered area 3, a mixing chamber 18 is provided, a carrier medium 11 flowing into it the axial direction at one end and on the other end a treatment medium 9 flowing out across the direction of flow of the carrier medium 11; this treatment medium is supplied by means of the feed element 5, which has outlet openings 13 on its end facing the tapered area 3, from which the treatment medium 9 flows out and begins to mix with the carrier medium. This process is continued in the nozzle gap 14.

If L2, the length of the displacement body 1, is greater than the depth of immersion L1 in the casing element 2, there is the possibility that when the distal end of this nozzle becomes clogged or destroyed, the distal end of the displacement body might be simply cut off by means of a disk cutter, so that operation of the nozzle can be begin again within a very short period of time.

The functioning of the nozzle is as follows:

The carrier medium 11 enters the pressure chamber 6.1 through the feed opening 10 and passes through the permeable holder 12 into the mixing chamber 18, going from there into the nozzle gap 14. The treatment medium 9 enters the feed element 5 and leaves it through the opening 13, so that it enters the mixing chamber 18 across the direction of flow of the carrier medium, preferably even at a right angle to it. The mixture undergoes acceleration through the tapered area 3, so that the mixing process is continued in the nozzle gap 14.

The diameter ratio of the inside diameter D1 of the nozzle pipe 2 and the outside diameter D2 of the displacement body 1 determines the throughput of the treatment medium and the carrier medium and the momentum in the core area 16 and in the near area 17 of the nozzle, like the ratio of the static pressure p2 of the carrier medium 11 and the total pressure p1 of the treatment medium at the outlet openings 13. The length of the mixing zone, starting from the mixing chamber 18 through the nozzle gap 14, has an influence on the throughput and the momentum, so that these parameters may be used to regulate the operation of the nozzle.

Claims

1. A nozzle for introduction and metered addition of a treatment medium into the exhaust gas stream in combustion processes in which a treatment medium and a carrier medium can be mixed together and sprayed out jointly, whereinthe nozzle has an outer casing element (2) and an inner displacement body (1) to form a nozzle gap (14); the displacement body (1) borders a mixing chamber (18) inside the casing element (2) and has a tapered area (3) in the transitional area between the mixing chamber (18) and the nozzle gap (14), and the mixing chamber (18) communicates with a pressure chamber (6.1) for the carrier medium out of which the carrier medium flows in a direction that is axially parallel to the nozzle gap (14); the feed element (5) for the treatment medium is provided, supplying treatment medium that enters into the mixing chamber (18), whereby after being accelerated in the tapered area (3), the two media enter into the nozzle gap (14) that serves as an additional mixing zone and the displacement body (1) has at least the same length as the casing element (2) in the direction of the nozzle outlet.

2. The nozzle according to claim 1, whereinthe outer casing element (2) and the feed element (5) are round tubular elements.

3. The nozzle according to claim 1, whereinthe treatment medium (9) is introduced into the mixing chamber (18) across the direction of flow, preferably at a right angle to the direction of flow of the carrier medium (11).

4. The nozzle according to claim 1, whereinthe displacement body (1) protrudes beyond the casing element (2).

5. The nozzle according to claim 1, whereinthe displacement body (1) is arranged replaceably with its tapered area (3) at the distal end of the feed element (5) for the treatment medium (9) as seen in the direction of flow, said feed element running through the mixing chamber (18) in the axial direction of the displacement body (1) and having outlet openings (13) for the treatment medium on the circumference in the vicinity of the tapered area (3).

6. The nozzle according to claim 5, whereinthe displacement body (1) is held exclusively by the feed element (5).

7. The nozzle according to claim 1, whereinthe feed element (5) for the treatment medium (9) runs centrally through the pressure chamber (6.1), connecting the two axial bordering walls (4, 7) to one another, and the bordering wall (4) assigned to the mixing chamber (18) has a holder (12) for the feed element (5), said holder being permeable for the carrier medium.

8. The nozzle according to claim 1, whereinthe casing element (2) is made of a heat-resistant material.

9. The nozzle according to claim 1, whereinthe casing element (2) is connected by a detachable connection (4.1) to a bordering wall (4).

10. The method for operating a nozzle according to claim 1, whereinthe throughput of the mixture of carrier medium and treatment medium and the momentum of this mixture in the core area and in the near area of the nozzle mouth are regulable by varying the ratio of the inside diameter of the casing element and the outside diameter of the displacement body, by varying the ratio of the static pressure (p2) of the carrier medium and the total pressure (p1) of the treatment medium at the outlet from the feed element and by varying the length of the mixing zone of the two media.