Spray nozzle and method for producing non-round spray cones

A spray nozzle having a nozzle housing, at least one swirl chamber which is disposed in the nozzle housing, and at least one exit opening, wherein the exit opening is disposed at the end of an exit duct which emanates from the swirl chamber and widens in the direction towards the exit opening, wherein a constriction is disposed at the transition from the swirl chamber to the exit duct, and wherein the angle of the wall steadily increases in the direction towards the exit opening or in portions remains identical, in which an angle of the wall of the exit duct at the exit opening, when viewed in the circumferential direction of the exit opening, is not constant.

CROSS-REFERENCE TO RELATED APPLICATIONS

This claims priority from German Patent Application No. 10 2015 207 741.1, filed on Apr. 28, 2015, the disclosure of which is hereby incorporated by reference in its entirety into this application.

FIELD OF THE INVENTION

The invention relates to a spray nozzle having a nozzle housing, at least one swirl chamber which is disposed in the nozzle housing, and at least one exit opening, wherein the exit opening is disposed at the end of an exit duct which emanates from the swirl chamber and widens in the direction towards the exit opening, wherein a constriction is provided at the transition from the swirl chamber to the exit duct, and the angle of the wall of the exit duct, starting from the constriction, steadily increases in the direction towards the exit opening or in portions remains identical. The invention also relates to a method for producing a spray cone having a cross section which is non-round, that is to say deviates from the circular shape.

BACKGROUND OF THE INVENTION

A double-swirl spray nozzle which has two swirl chambers, one exit duct which widens in the direction towards an exit opening emanating from each of said swirl chambers, is disclosed in European Patent Document EP 1 491 260 B1. An angle of the wall of the exit duct in relation to a longitudinal central axis of the exit duct steadily increases in a few portions in the direction towards the exit opening while said angle remains identical in other portions. The double-swirl spray nozzle shown has both exit openings on the same side of the nozzle housing. The two exit openings are disposed at an angle in relation to one another. The double-swirl spray nozzle described is employed in flue gas purification plants, for example, in particular in gas scrubbers.

German Patent Document DE 100 33 781 C1 describes a double-swirl spray nozzle which has two swirl chambers and exit ducts which in each case emanate from the swirl chambers and run up to an exit opening. The exit openings are oriented towards opposite sides of the housing.

SUMMARY OF THE INVENTION

By way of the invention a spray nozzle is intended to be improved in terms of the flexibility of the application thereof.

According to the invention, to this end a spray nozzle having a nozzle housing, at least one swirl chamber which is disposed in the nozzle housing, and at least one exit opening is provided, wherein the exit opening is disposed at the end of an exit duct which emanates from the swirl chamber and widens in the direction towards the exit opening, wherein a constriction is disposed at the transition from the swirl chamber to the exit duct, and wherein the angle of the wall of the exit duct, starting from the constriction, steadily increases in the direction towards the exit opening or in portions remains identical, in which a shape of the exit opening deviates from a circular shape, and in which an angle of the wall of the exit duct at the exit opening, when viewed in the circumferential direction of the exit opening, is not constant.

By virtue of a shape of the exit opening deviating from a circular shape and an angle of the wall of the exit duct at the exit opening, when viewed in the circumferential direction of the exit opening, not being constant, a cross-sectional shape of the delivered spray cone may deviate from a circular shape. This is especially advantageous when the spatial conditions make a non-circular spray cone appear to be ideal in order for as good a coverage as possible to be achieved with the spray cone. This may be the case in particular in gas scrubbers, for example, when spray nozzles are disposed in the region of the wall of a gas scrubber having a circular-cylindrical shape. Here, liquid which is being sprayed into the gas scrubber by the spray nozzle should typically be prevented from impacting directly on the wall of the gas scrubber. By way of the nozzle according to the invention a cross-sectional shape of the spray cone that deviates from the circular shape may be set such that the spray cone delivered by the spray nozzle is propagated into the interior space of the gas scrubber and not in the direction towards the wall. A constriction between the swirl chamber and the exit duct may be formed by an encircling edge and/or by an initial portion of the exit duct, wherein the wall of the exit duct in this initial portion runs substantially parallel with a longitudinal central axis of the exit duct. The invention may be applied in any type of nozzle having a swirl chamber, for example in tangential nozzles, axial nozzles, and also in spill-back nozzles. An incident flow to the swirl chamber in the case of axial nozzles and spill-back nozzles is typically performed in an axial manner such that a swirl insert is optionally provided.

In a refinement of the invention the exit duct at the transition from the swirl chamber to the exit duct has a circular cross section.

Such a circular cross section of the exit duct at the transition from the swirl chamber to the exit duct is advantageous for good distribution of the liquid to be sprayed in the delivered spray cone. A hollow-cone spray is delivered, for example. The circular cross section of the exit duct at the transition from the swirl chamber to the exit duct then provides uniform distribution of the liquid in the delivered hollow-cone spray.

In a refinement of the invention the angle of the wall of the exit duct in relation to the longitudinal central axis of the exit duct at the exit opening is in a range between 0° and 90°.

Surprisingly, it has been established that the angle of the wall of the exit duct at the exit opening may vary in a very large range, specifically between 0° and 90° in relation to the longitudinal central axis of the exit duct, the spray behaviour of the spray nozzle nevertheless still remaining good. Despite the large angle at which the angle of the wall of the exit duct may lie in relation to the longitudinal central axis, good and uniform distribution of the liquid in the delivered spray cone may especially still be achieved.

In a refinement of the invention an angle of the wall of the exit duct at the exit opening, when viewed across the circumference of the exit opening, varies between 32.5° and 65° in relation to the longitudinal central axis of the exit duct.

Such dimensioning of the variation of the angle of the wall leads to an oval spray jet having very uniform liquid distribution within the spray jet being configured. If the angle between mutually opposite points of the wall of the exit duct at the exit opening is measured, the angle of the wall varies between 75° and 130°.

In a refinement of the invention the exit opening has an oval or elliptic shape.

In this way an individual spray cone may be imparted an oval or elliptic cross-sectional shape. On account of the design of the spray nozzle according to the invention, this is possible with good liquid distribution within the spray cone.

In a refinement of the invention two swirl chambers and two exit openings are provided, wherein the exit openings are disposed such that spray jets exit through the two exit openings on the same side of the housing.

In a refinement of the invention two swirl chambers and two exit openings are provided, wherein the exit openings are disposed such that spray jets exit through the two exit openings on opposite sides of the housing.

In a refinement of the invention the nozzle housing is cast or injection-moulded and is subsequently fired or sintered.

In this way, the variable angles of the wall of the exit duct and the shape of the exit opening that deviates from the circular shape may be implemented in a highly precise and simultaneously economical manner.

The underlying issue of the invention is also solved by a method having the features of claim9.

DETAILED DESCRIPTION

FIGS. 1 and 2show a spray nozzle10according to the invention, which has a nozzle housing12having two swirl chambers14,16, and two exit openings18,20. InFIG. 1the observer sees into the two exit ducts22,24, which then each transition into one of the swirl chambers14,16, respectively. The two swirl chambers14,16are connected to a common connector26. Liquid to be sprayed is supplied via the connector26, reaches the interior of the two swirl chambers14,16, and is supplied to each of the swirl chambers14,16in a tangential manner, from there through in each case one constriction28,30reaches the respective exit duct22,24, and in the form of a respective hollow-cone spray then departs from the housing12.

It can be seen already by means of the illustration ofFIG. 1that the shape of the two exit openings18,20in each case deviates from a circular shape. The exit openings18,20each have an elliptic shape, wherein it has to be considered that the longitudinal central axes of the two exit ducts22,24that end at the exit openings18,20are not disposed so as to be perpendicular to the drawing plane ofFIG. 1. Rather, the longitudinal central axes of the exit ducts22,24are disposed so as to diverge. On account thereof, the two spray jets generated are mutually diverging. A respective configuration of a double-swirl spray nozzle is known from European Patent Document EP 1 491 260 B1 to which reference is made in this context.

Despite the illustration ofFIG. 1being slightly distorted due to the oblique arrangement, it may also be derived from this figure that a cross section of the exit ducts22,24at a point28or30, respectively, that is to say in each case at the transition from the swirl chambers14,16to the exit duct22,24, respectively, is circular. On account of the circular cross section at the transition from the respective swirl chamber14,16to the exit ducts22,24, uniform distribution of the liquid within the delivered spray jet is achieved.

Now, by virtue of the exit openings20deviating from the circular shape, a cross-sectional shape which in each case deviates from the circular shape may be imparted to both delivered spray cones. In the nozzle illustrated inFIG. 1a hollow-cone spray having an elliptic cross section exits from each of the exit openings18,20. An approximately oval spray cone (cf.FIG. 8) results from superimposing these two elliptic spray cones.

The illustration ofFIG. 3shows in portions a schematic sectional view onto the sectional plane III-III ofFIG. 2. It is the intention ofFIG. 3to clarify the shape of the exit openings18,20and of the exit ducts22,24in the sectional plane III-III. For this reason, only the exit opening20and the exit duct24were illustrated in a sectional manner inFIG. 3; the exit opening18and the exit duct22are however identically configured. The same applies to the illustration ofFIG. 4. Double spray nozzles or multiple spray nozzles having exit ducts configured in various manners are also possible in the context of the invention. A longitudinal central axis32of the exit duct24of the spray nozzle10is indicated in the illustration ofFIG. 3. A portion of the swirl chamber16can still be identified at the upper end of the illustration ofFIG. 3. The swirl chamber16ends at a slightly rounded edge34, and the exit duct24begins there. As can be seen, a wall of the exit duct24is disposed so as to be substantially parallel with the longitudinal central axis32at the beginning of the exit duct24, that is to say directly after the rounded edge34. In fact, the wall of the exit duct24in this region in relation to the longitudinal central axis32has an angle of approx. 3° such that the exit duct24opens in the flow direction starting from the beginning thereof. On account thereof, a draft angle which is advantageous in the manufacture of the spray nozzle is formed. In the further profile of the exit duct24, that is to say in the flow direction which is indicated by means of an arrow36, an angle between the longitudinal central axis32and a wall of the exit duct24steadily increases until reaching a value of 65° and then continues at this constant angle up to the exit opening20. On account thereof, a linear delimitation having an opening angle of 130° is disposed upstream of the exit opening20in the sectional plane III-III, as is illustrated inFIG. 3. Proceeding from a value of approx. 0° in relation to the longitudinal central axis, in the shown embodiment of 3°, that is to say from an arrangement in which the longitudinal central axis and the wall of the exit duct24are substantially parallel at the beginning of the exit duct, the angle of the wall of the exit duct24thus either steadily increases or is constant in portions.

A spray disintegrating into individual droplets and departing in the flow direction36will widen when passing through the exit duct24as soon as said spray has passed through the constriction30which is formed substantially by the encircling edge34, to the extent that this is permitted by the wall of the exit duct24. In the sectional plane III-III the spray cone will thus depart from the exit opening20having a spray angle of somewhat less than 130°.

The illustration ofFIG. 4shows in portions a schematic sectional view onto the sectional plane IV-IV inFIG. 2. The exit duct24at the beginning thereof, that is to say at the transition from the swirl chamber16to the rounded edge34, firstly has a wall which is disposed so as to be substantially parallel with the longitudinal central axis32and in fact assumes an angle of 3° in relation to the longitudinal central axis32. In the flow direction, which is indicated by the arrow36, the angle of the wall of the exit duct24in relation to the longitudinal central axis32then steadily increases until reaching a value of 32.5°. The wall of the exit duct24then runs at this constant angle up to the exit opening20. The region directly upstream of the exit opening20in the sectional view of the plane IV-IV thus runs in a linear manner. On account thereof, a linear delimitation having an opening angle of 75° is disposed upstream of the exit opening20in the sectional plane IV-IV. However, it should be remembered that the angle of the wall of the exit duct24varies along the circumference of the exit opening20and in the section plane III-III ofFIG. 2, cf.FIG. 3, assumes an angle of 65° in relation to the longitudinal central axis32. The region directly upstream of the exit opening20is thus not circular-conically shaped but has an irregular shape which is determined in that the angle of the wall of the exit duct24across half of the length of the circumference of the exit opening20varies from a value of 32.5° in relation to the longitudinal central axis to a value of 65° in relation to the longitudinal central axis and then back to the former value.

A spray of droplets exiting from the exit duct24will widen as far as the exit opening20as soon as said spray has passed through the constriction formed by the edge34, and to the extent that this is permitted by the wall of the exit duct24, such that said spray will exit at the exit opening in the plane IV-IV having a spray angle of somewhat less than 75°.

As a result, a spray cone exiting the exit duct24thus has a geometry having a non-round and in the illustrated embodiment elliptic cross section. The spray angle in the sectional plane is somewhat less than 130°, cf.FIGS. 2 and 3. The spray angle in the sectional plane IV-IV is somewhat less than 75°, cf.FIGS. 2 and 4.

The significant advantage of the nozzle according to the invention here is that such a cross section of an exiting spray cone, which generally deviates from a circular shape, is achieved only by way of the design of the wall and especially of the angle of the wall of the exit duct24in relation to the longitudinal central axis32. By contrast, the construction of the swirl chamber16and of the housing of the nozzle does not have to be modified. The exit duct24may be adapted according to the required type of application and to the desired cross-sectional shape of the exiting spray cone. In order for the spray cone having a non-round cross section or one deviating from a circular shape, respectively, to be produced, a swirl is generated in the swirl chamber14,16, in order to generate centrifugal forces which act on the liquid flowing through and in order to thus set the latter in rotation. By means of the constriction28,30which is formed substantially by the encircling edge34and lies between the swirl chamber14,16and the exit duct22,24, the volumetric flow through the nozzle is throttled and set. The tapering which is formed by the edge34and the subsequent beginning of the exit duct22,24here is configured such that the liquid flowing therethrough is uniformly distributed on the circumference of this constriction. Here, the swirl generated in the swirl chamber and the liquid thus rotating in the swirl chamber play an important part. The non-round spray cone is then shaped in the exit duct22,24by the wall of the exit duct, which is constructed in a non-rotationally symmetrical manner. On account of dissimilar gradients or of dissimilar angles, respectively, the departure angle of the droplets up to the exit opening18,20is individually predefined. The departure angle of the droplets is predefined depending on the wall portion in which the droplets are located and on which angle this wall portion assumes in relation to the central axis, and as a result a spray cone having a non-round cross section is shaped on account thereof.

This enables a very flexible manufacturing method in the case of nozzles made from ceramics or sintered materials. The nozzle housing12having the two swirl chambers and the connector26may always be manufactured by means of the same moulds. Only the nozzle mouths, that is to say the exit ducts22,24are modified according to the desired type of application. Modified moulds may then be used to this end. A ceramic compound is thus shaped as desired and subsequently fired. Nozzles having various cross-sectional shapes of the delivered spray jets may be manufactured in a comparatively simple and cost-effective manner in this way. Accordingly, one may proceed in an analogous manner in the case of nozzles which are manufactured from sintered materials. For example, a metal powder is mixed here with a plastics binder, injected into a mould, and subsequently sintered so as to then obtain a nozzle which is composed of a metallic sintered material. However, the spray nozzle according to the invention may also be cast from plastics or metal, for example, be manufactured in a layered construction or else made mechanically by means of subtractive machining methods.

A significant advantage of the nozzle according to the invention is that uniform distribution of the liquid in the delivered spray jets may be guaranteed by maintaining the shape of the swirl chambers and also the circular shape of the exit duct at the beginning of the exit ducts22,24. Only the cross-sectional shape of the spray jets is modified by the design of the exit ducts and the shape of the exit openings18,20.

The illustration ofFIG. 5in a plan view shows a spray nozzle50according to the invention, according to a further embodiment of the invention. The spray nozzle50is also configured as a swirl-spray nozzle and has a housing having a swirl chamber52and an exit duct54which extends from a transition from the swirl chamber52to the exit duct54up to an exit opening56. InFIG. 5, the observer sees, counter to the spray direction of the spray nozzle50, into the exit duct54and into the swirl chamber52.

It can be seen that the exit duct at the transition from the swirl chamber52to the exit duct54has a circular cross section. In the further profile of the exit duct54towards the exit opening56, the cross section of the exit duct54changes, the latter also widening in this direction. The exit duct54in the direction towards the exit opening56assumes a cross-sectional shape which approximately corresponds to a flattened circle on one side. A spray cone which is delivered by the spray nozzle50during operation is also shaped by this shaping of the exit duct54. On a planar area which lies perpendicular to a central axis58of the swirl chamber52, the spray nozzle50would generate a spray impingement having an area which is approximately the shape of the exit opening56or larger. Such a spray impingement is advantageous, for example, when the spray nozzle50is to be disposed close to the wall of a processing space and when it is undesirable for the wall of the processing space to be conjointly sprayed.

The illustration ofFIG. 6shows an arrangement having a conventional double-swirl spray nozzle60which has two exit openings which are disposed beside one another and which in each case deliver a spray cone which has a circular cross section. The spray cones here are not mutually parallel but oriented away from one another such that the central axes of the two swirl chambers of the spray nozzle60diverge as the spacing from the exit openings increases when viewed in the spray direction.

On account thereof a spray geometry62which has a shape which narrows in the centre results when the two spray cones are superimposed. However, it is particularly disadvantageous that a proportion64of a spray geometry that is drawn with shaded lines inFIG. 6does not in fact become effective. Rather, this proportion64of the spray geometry would impact a wall66of a processing space.

This can also be seen in the side view ofFIG. 7. The spray which in the side view ofFIG. 7itself per se is conical impacts the wall66of the processing space such that the hatched proportion64of the spray geometry62in fact impacts the wall66and can no longer be utilized.

The illustration ofFIG. 8schematically shows the spray nozzle10according to the invention ofFIGS. 1 to 4, in the installed state, especially in a gas scrubber40which is schematically illustrated in portions and of which only a portion of the wall66thereof is illustrated. The observer, inFIG. 4, sees inside the circular-cylindrical gas scrubber from above. The spray nozzle10is disposed in the peripheral region of the gas scrubber40, fastenings not being illustrated. The spray nozzle10delivers two spray cones, only the resulting superimposed spray geometry72being illustrated. As has been discussed, one spray cone having an approximately elliptic shape exits each of the exit openings18,20. When superimposed, a spray geometry72having an oval cross section then results. It can be readily seen that such an oval cross-sectional shape of the spray jet72is desired on account of the arrangement of the spray nozzle10in the peripheral region of the gas scrubber40. This is because it can be ensured on account thereof that in comparison with a spray cone having a circular cross section only very little of the sprayed liquid reaches the wall of the gas scrubber40at the defined spacing.

The cross-sectional shape of a delivered spray geometry, regardless of whether this is the cross-sectional shape of an individual delivered spray cone or the cross-sectional shape of two or a plurality of superimposed spray cones, may be set within wide limits by way of the spray nozzle according to the invention. Depending on the given type of application and on the cross-sectional shape desired in the special type of application, an optimal spraying result may be achieved on account of the above.

The embodiment illustrated shows a double-swirl spray nozzle having two exit openings which deliver spray jets in the same direction. It is obvious that the invention may also be applied in other types of spray nozzles, especially in swirl spray nozzles which have only one exit opening, or in double-swirl spray nozzles which have two exit openings from which spray jets exit in opposite directions. The invention may also be applied in multiple spray nozzles which have more than two exit openings.

In relation to the wall66of the processing space, the double-swirl spray nozzle10according to the invention, according toFIG. 8, is disposed at the same point as the spray nozzle60inFIG. 6. However, it can be seen inFIG. 8that a spray geometry72which has an oval cross-sectional shape may be generated by the double-swirl spray nozzle10according to the invention. This is achieved by superimposing the two spray cones which are generated by the double-swirl spray nozzle10. It can be seen already inFIG. 8that only a very small proportion74of the spray geometry72generated impacts the wall66and is thus lost.

This can also be seen in the side view ofFIG. 9. The spray geometry72having an oval cross-sectional shape has a significantly lower loss on the wall, since the spray geometry72impacts the wall66only by way of the extreme periphery of the former. In comparison to the arrangement having the conventional double-swirl spray nozzle60ofFIGS. 6 and 7, an obviously reduced loss on the wall may be achieved on account thereof, and coverage across a large area of the processing space may nevertheless be achieved with the double-swirl spray nozzle10according to the invention.

The double-swirl spray nozzle10according to the invention thus enables the shaping of the delivered spray geometry72and, on account thereof, the use of large spray angles without losing any unused sprayed medium on the wall66.

The illustration ofFIG. 10shows a plan view onto an arrangement having two conventional double-swirl spray nozzles60. The double-swirl spray nozzles60each generate two spray cones, each having a circular cross-sectional shape. When superimposed, a spray geometry76which in the plan view has approximately the shape of a balloon which has been narrowed twice results. It can be seen that by superimposing the four spray cones delivered by the double-swirl spray nozzles60in conjunction with a large spray angle, coverage across a large area may be achieved by the spray geometry76. However, a significant proportion78of the spray geometry76impacts the wall66of the processing space, this being indicated by the hatched proportion78of the spray geometry76.

The side view ofFIG. 11clearly shows the delivered spray geometry76which in part impacts the wall66such that the proportion78of the spray geometry76is lost, and the sprayed medium of this proportion78can no longer be utilized in the processing space, for example for gas scrubbing.

The illustration ofFIG. 12shows an arrangement having two double-swirl spray nozzles80according to the invention, according to a further embodiment of the invention. The respective exit duct and the respective exit opening of the double-swirl spray nozzles80according to the invention are shaped such that, when superimposed, a spray geometry82which in the plan view ofFIG. 12has the shape of a rectangle having rounded corners results. It can be clearly seen that coverage across a large area may be achieved by the spray geometry82, as is the case in the arrangement ofFIG. 10, but that the proportions84which are hatched inFIG. 12are obviously smaller than the proportions78of the arrangement ofFIG. 10. The shaping of the spray cones to form a non-round cross-sectional shape in the double-swirl spray nozzles80according to the invention leads to an obvious reduction of the losses on the wall, this being clearly identifiable on account of the hatched proportions84of the spray geometry82being obviously smaller than the proportions78in the case of the arrangement ofFIG. 10. Using the arrangement having the two double-swirl spray nozzles80according to the invention, the sprayed medium may thus be utilized in a substantially better manner.

The side view ofFIG. 13shows the arrangement ofFIG. 12in a side view. It can be seen that only a very small proportion of the spray geometry82impacts the wall66of the processing space.

The illustration ofFIG. 14shows an arrangement having two double-spray nozzles81according to the invention, according to a further embodiment of the invention. The respective exit duct and the respective exit opening of the double-swirl spray nozzles81according to the invention are shaped such that, when superimposed, a spray geometry83results. The spray geometry83is non-symmetrical to the extent that the former, proceeding from the spray nozzles81, extends farther to the interior space of the circular wall66than to the wall66.

The view ofFIG. 15shows the arrangement ofFIG. 14in a side view. It can be seen that on account of the non-symmetrical spray geometry83, only a very small proportion of the generated spray of droplets impacts the wall66, and that a large area of the processing space in the radial direction from the wall66to the inside, that is to say towards the right inFIG. 15, may be covered.

The illustration ofFIG. 16shows an arrangement having two conventional swirl spray nozzles86in a plan view. The two swirl spray nozzles86each generate one spray cone having a circular cross-sectional shape. The swirl spray nozzles86are supplied with a medium to be sprayed from a common collective pipeline88. The swirl spray nozzles86are chosen such that they have a large spray angle and, on account thereof, are able to impinge as large a proportion of a processing space as possible with the delivered spray cone.

However, this results in a proportion94of the respectively delivered spray cone92, which is hatched inFIG. 16, impacting the collective pipeline88. On account thereof, sprayed medium is lost which may not be used for gas scrubbing, for example; there is moreover the risk of the delivered spray cones92in the long term damaging the collective pipeline88.

FIG. 17shows a side view of the arrangement ofFIG. 16. It can be clearly seen that the proportions94of the delivered spray cones92impact the collective pipeline88.

The illustration ofFIG. 18shows a plan view onto a further arrangement having two conventional swirl spray nozzles96. The spray angle of the two swirl spray nozzles96has now been chosen to be smaller than in the case of the swirl spray nozzles86ofFIGS. 16 and 17. On account thereof, it is indeed avoided that the delivered spray cone98impacts the collective pipeline88, cf. also the side view ofFIG. 19. However, at the same time it has to be taken into account that the impingement by the delivered spray cones98is substantially smaller than in the case of the swirl spray nozzles86ofFIGS. 16 and 17.

FIG. 20shows a plan view onto an arrangement having two swirl spray nozzles90according to the invention. The two swirl spray nozzles90each deliver a spray cone102which have an oval-shaped cross section. It can be seen by means ofFIG. 20that an impingement across a large area of the processing space may be achieved by superimposing the two spray cones102. It can be seen from the side view ofFIG. 21that it is at the same time avoided that the delivered spray cones102impact the collective pipeline88.

The illustration ofFIG. 22shows a plan view onto an arrangement having two swirl spray nozzles91according to the invention. The two swirl spray nozzles91each deliver a spray cone103which has an irregularly-shaped cross section. The spray cones103extend further in the direction away from the collective pipeline88into the processing space than in the direction towards the collective pipeline88. On account thereof, an impingement of the processing space across a large area may be achieved, on the one hand, and it is avoided, on the other hand, that the delivered spray cones103impact the collective pipeline88, cf. the side view inFIG. 23.

The illustration ofFIG. 24shows an arrangement of two conventional double-swirl spray nozzles104wherein each of the double-swirl spray nozzles104delivers an upwardly directed spray cone106and a downwardly directed spray cone108, cf. also the side view ofFIG. 25.

The two double-swirl spray nozzles104are fed from the common collective pipeline88. Large spray angles are chosen in order to achieve impingement across a large area by the spray cones106,108. However, it can be seen in the side view ofFIG. 25that the upwardly exiting spray cone106in part impacts the collective pipeline88. On account thereof, medium to be sprayed is lost, on the one hand, and there is the risk of damaging the collective pipeline88, on the other hand.

The illustration ofFIG. 26shows a plan view onto an arrangement having two conventional double-swirl spray nozzles110. The double-swirl spray nozzles110each deliver a spray cone112having a small spray angle upwardly, and a spray cone114having a large spray angle downwardly, cf. also the side view ofFIG. 27. On account thereof, spraying of the collective pipeline88by the upwardly delivered spray cones112may indeed be prevented, cf. the side view ofFIG. 27. However, the impingement of the processing space by the upwardly delivered spray cones112is comparatively small and unsatisfactory.

The illustration ofFIG. 28shows an arrangement having two double-swirl spray nozzles100according to the invention. The double-swirl spray nozzles100each deliver a spray cone114having a circular cross section downwardly and each a upwardly, spray cone116having an oval cross section cf. also the side view ofFIG. 29. On account thereof, by way of the superimposition of the two spray cones116which have an oval-shaped cross section, an impingement across a large area of the processing space is also achieved in the upward spray direction; at the same time, however, it can also be ensured that the collective pipeline88is not sprayed by the upwardly delivered spray cones116.

The illustration ofFIG. 30shows an arrangement having two double-swirl spray cones101according to the invention. Each of the double-swirl spray cones101delivers a spray cone105having a circular cross section downwardly and a spray cone107having an irregularly-shaped cross section upwardly. As can be seen from the side view ofFIG. 31, it is achieved by the irregularly-shaped spray cone107that the processing space is impinged across a large area, but that the collective pipeline88is not hit by the upwardly delivered spray jet107. The upwardly directed exit openings of the double-swirl spray nozzles101to this end are configured such that the spray jet107extends away from the collective pipeline88further into the processing space than in the direction towards the collective pipeline88. As has been discussed, this is achieved in that the wall of the exit opening on that side that faces the collective pipeline88has a steeper angle than on that side that faces away from the collective pipeline88.

The illustration ofFIG. 32shows an arrangement having two conventional double-swirl spray nozzles118. Each of the double-swirl spray nozzles118delivers two spray cones each having a circular cross section, wherein the central axes of the swirl chambers of each double-swirl spray nozzle118, when viewed in the spray direction, diverge slightly, as can be seen in the side view ofFIG. 33. The delivered spray geometry120indeed ensures coverage across a large area, but in portions sprays the collective pipeline88, cf. alsoFIG. 33.

FIG. 34shows a further arrangement having two conventional double-swirl spray nozzles122, wherein a smaller spray angle has been chosen in comparison to the double-swirl spray nozzles118ofFIGS. 32 and 33. As can be derived fromFIG. 35, spraying of the collective pipeline88may now be avoided; however, only an obviously smaller area of the processing space is impinged by the sprayed medium, as can be readily established by means of a comparison betweenFIGS. 32 and 34, or33and35, respectively.

The illustration ofFIG. 36shows a plan view onto an arrangement having two double-swirl spray nozzles130according to the invention. Each of the double-swirl spray nozzles130delivers two spray cones, wherein the first delivered spray cone132has a circular cross section, and the second delivered spray cone134has an oval cross section.

The two swirl chambers of the double-swirl spray nozzles130are disposed at an angle to one another such that a spacing between the central axes of the two swirl chambers is enlarged when viewed in the spray direction.

The total spray jet resulting from the superimposition of the spray jets132,134now has an irregular shape. It may, however, be achieved by superimposition that impingement across a large area of the processing space is achieved and at the same time that spraying of the collective pipeline88is avoided, cf. also the side view ofFIG. 37. It can be seen in the illustration ofFIG. 37that the spray cones132,134are mutually penetrating and on account thereof the resulting superimposed spray geometry excludes the region of the collective pipeline88.

The illustration ofFIG. 38shows a further arrangement having two double-swirl spray nozzles136according to the invention. Each of the double-swirl spray nozzles delivers two spray cones in the approximately the same downward direction, wherein a first spray cone138has a circular cross section, and a second spray cone140has an irregularly-shaped cross section. The irregularly-shaped cross section here is configured such that the spray cone140extends away from the double-swirl spray nozzle136further into the processing space, that is to say away from the collective pipeline, than in the direction towards the collective pipeline88. The spray geometry illustrated in the side view inFIG. 39results from the superimposition of the two spray jets138and the two spray jets140. It can be seen that the processing space is covered across a large area but that the collective pipeline88is not impinged.

A significant aspect of the invention thus lies in generating a desired shape of spray impingement by superimposing at least two spray cones, wherein at least one of the two spray cones has a non-circular cross section.