WO2007071235A1

WO2007071235A1 - A nozzle arrangement and a method of mounting the nozzle arrangement in a wall of a spray drying apparatus

Info

Publication number: WO2007071235A1
Application number: PCT/DK2005/000808
Authority: WO
Inventors: Martin Nowak
Original assignee: Niro A/S
Priority date: 2005-12-20
Filing date: 2005-12-20
Publication date: 2007-06-28

Abstract

The nozzle arrangement (10) has a nozzle lance (11) and a nozzle having a longitudinal axis. A securing device (20) is adapted to secure the nozzle lance to a ceiling or wall of a drying chamber of the spray drying apparatus. The securing device comprises adjustment means including at least a first and a second adjustment disk (21, 22) releasably connected with each other, by which it is possible to shift the longitudinal axis of the nozzle.

Description

Title of the invention

A nozzle arrangement and a method of mounting the nozzle arrangement in a wall of a spray drying apparatus.

Field of the invention

The present invention relates to a nozzle arrangement for a spray drying apparatus, comprising a nozzle lance, a nozzle having a longitudinal axis defining an axial direction, and a securing device adapted to secure the nozzle lance to a ceiling or wall of a drying chamber of the spray drying apparatus. The invention furthermore relates to a method of mounting the nozzle arrangement.

Background of the invention

In such a nozzle arrangement, a well-defined, symmetrical and homogenous flow of the drying gas in the drying chamber is generally aimed at. This aim is even more pronounced in spray drying apparatus to be utilized in the pharmaceutical field. Thus, a number of precautions are taken in order to secure the desired flow pattern, including accurate positioning of the longitudinal axis of the nozzle, for instance in a substantially vertical direction. However, despite all precautions taken it has proven difficult to achieve this aim. This is, i.a., due to the fact that it is difficult to control the flow conditions in the supply pipe for drying gas, in the nozzle arrangement and in the drying chamber. Furthermore, as such spray drying apparatus in general and the drying chamber thereof in particular assumes relatively large dimensions, even small variations in for instance the inclination of the ceiling or wall supporting the nozzle of the drying chamber may entail relatively large deviations of the longitudinal axis and hence of the mouth of the nozzle. For instance, in an arrangement in which the mouth of the nozzle is located 1 m from the wall of the drying chamber, an inclination of the wall of 2° causes a deviation of approximately 35 mm of the mouth of the nozzle from its intended position. This deviation may entail inaccuracies in the flow pattern, which in turn results in that the spray drying process is not carried out in an optimal manner and that deposits may form on the nozzle and/or the walls of the drying chamber. This is particularly critical when spray drying in the pharmaceutical field.

Summary of the invention With this background it is an object of the invention to provide a nozzle arrangement of the kind mentioned in the introduction, by which it is possible to compensate for slight inaccuracies in the flow.

In a first aspect of the invention, this and further objects are achieved in that the securing device comprises adjustment means including at least a first and a second adjustment disk releasably connected with each other, said adjustment means being adapted to shift the longitudinal axis of the nozzle.

By providing the securing device with adjustment means to shift the longitudinal axis of the nozzle it is possible to adjust the position of the mouth of the nozzle and hence compensate for inaccuracies in the flow resulting from varying positioning and tolerances of parts of the spray drying apparatus or in the nozzle arrangement. The releasable connection of the first and second adjustment disks makes it easy and straightforward to move the adjustment disks relative to each other. Furthermore, the parts of at least the securing device and possibly of the entire nozzle arrangement may be disconnected with a view to maintenance, cleaning and/or replacement of parts.

In an advantageous embodiment, each of the first and second adjustment disks has a cross-section in at least one radial direction transverse to said axial direction, which cross-section tapers at an angle from one peripheral point to a diametrically opposite peripheral point, the first and second adjustment disks being adapted to be releasably connected with each other in a plurality of angular positions relative to each other. This provides for a structurally simple design of the nozzle arrangement and makes it possible to tilt the longitudinal axis of the nozzle to a certain degree by rotating the adjustment disks with respect to each other.

The angle of taper of each of the first and second adjustment disks may vary according to the dimensions of other parts of the nozzle arrangement, but preferred values lie in the interval 0 to 5°. Preferably, the angles of taper of the first and the second adjustment disk are identical. This makes it possible to obtain a position, in which the taper of the respective adjustment disk compensate for each other, i.e. corresponding to an adjustment of 0°.

Depending on the dimensions of the adjustment disks and of the desired degree of adjustment possibilities, the first and second adjustment disks may be releasably connected with each other in any suitable manner. However, in an advantageous embodiment the first adjustment disk is, along a circumference, provided with a plurality of axially extending apertures, preferably four to eight apertures, most preferably six apertures, for accommodation of fastening means adapted to cooperate with apertures in the second adjustment disk. In order to provide a fine adjustment of the angular position, each said axially extending aperture in the first adjustment disk may be a slot extending in the direction of said circumference.

As at least the parts of the securing device may be disconnected from each other, e.g. with a view to cleaning, the angular position of the adjustment disks relative to each other is preferably indicated by a marking on each adjustment disk. Such markings may assume any suitable form; however, in an advantageous embodiment, the marking on the first adjustment disk is a scale on the edge surface of the first adjustment disk, and the marking on the second adjustment disk is an indication, preferably in the form of a number and/or lettering on the top surface of the second adjustment disk.

In a preferred embodiment, the securing device furthermore includes a base disk adapted to be secured to a ceiling or wall of the drying chamber, the second adjustment disk being adapted to be connected with the base disk, the first adjustment disk being connected with the nozzle lance via a flange. This provides for a structurally simple design.

The connection between the second adjustment disk and the base disk may be carried out in any suitable manner. In an advanta- geous design, the second adjustment disk is, along a circumference, provided with a plurality of axially extending apertures, preferably four to eight apertures, most preferably six apertures, for accommodation of fastening means adapted to cooperate with apertures in the base disk. In an advantageous further development of this preferred embodiment, at least the second adjustment disk is adapted to be connected with the base disk in a plurality of positions transversely relative to the axial direction, each of the apertures in the second adjustment disk being formed as a long hole extending in a direction transversely to the axial direction. This design makes it possible to shift the longitudinal axis of the nozzle in the transverse direction as well.

In order to retain the information regarding the position of the adjustment disks relative to the base disk in the direction transversely to the axial direction, this position is preferably indicated by markings on the second adjustment disk and on the base disk. Advantageously, the marking on the second adjustment disk is a scale on the top or edge surface of the second adjustment disk, and the marking on the base disk is a number and/or lettering on the top surface of the base disk.

Furthermore, means for adjusting the position of the nozzle lance in the axial direction may be provided. Preferably, said means comprise an adjusting screw device, and the position of the nozzle lance in the axial direction is preferably indicated by a marking in the form of a scale on the nozzle lance.

The markings may be formed in any suitable manner. Prefera- bly, however, they indicate a combination of numbers and/or lettering providing an unambiguous code for each position of the longitudinal axis of the nozzle. This makes it possible to retain information regarding the positions of the relevant parts of the nozzle arrangement relative to each other and to re-create these positions when the parts are again connected with each other.

In an embodiment, which makes it possible to improve the drying conditions even further, the nozzle arrangement includes a tube for gas surrounding said nozzle lance. The space formed between the tube and the nozzle lance is preferably adapted to receive a conditioning gas. In a development of this embodiment, a connection piece adapted to be connected with a supply pipe for the conditioning gas is preferably positioned eccentrically with respect to the longitudinal axis of the nozzle. In order to suppress the vortex formed by the eccentric position of the supply pipe a plurality of vanes may be positioned near a downstream end of the nozzle lance.

The velocity of the conditioning gas is preferably relatively low and may lie in the interval 5 to 10 m/s, preferably 6 to 8 m/s.

Depending on the field of application of the nozzle arrange- ment, the pressure may vary. Preferably, the nozzle arrangement is designed for approximately 1 bar above atmospheric pressure.

In a further aspect of the invention, a method of mounting a nozzle arrangement in a ceiling or wall of a spray drying apparatus is provided. The method comprises the steps of determining a desired position of the longitudinal axis of the nozzle, and adjusting the adjustment means according to the desired position.

In case the nozzle arrangement comprises markings to indicate the position of the longitudinal axis of the nozzle, the method further comprises the step of reading the markings. In the following the invention will be described in further detail by means of an embodiment thereof and the appended drawings.

Brief description of the drawings

Fig. 1 shows a schematic side view of a spray drying apparatus with an embodiment of a nozzle arrangement according to the invention;

Fig. 2 shows a perspective view, on a larger scale, of a detail of an embodiment of the nozzle arrangement;

Fig. 3 is a cutaway view of the detail shown in Fig. 2; Fig. 4 is an exploded side view of a detail of an embodiment of the nozzle arrangement;

Figs. 5 to 7 show schematic side views of an embodiment of the nozzle arrangement in different positions. Detailed description of the invention and of preferred embodiments

Fig. 1 depicts a spray drying apparatus 1 in which a liquid feed to be atomised and dried is processed. In a manner known per se the spray drying apparatus 1 comprises a drying chamber 2 having any suitable form to which the liquid feed is supplied via a supply pipe 3. Drying air or gas is supplied in a known manner. In the embodiment shown, the drying chamber 2 comprises an upper part 4 and a lower part 5. The upper part has an essentially cylindrical wall 6 closed in the top with a wall forming a ceiling 7, and the lower part having a downward tapering frusto-conical wall 8. The downward tapering frusto- conical wall enters into an outlet 9 (not shown in detail) for collecting the particles attained after the spray drying process. A nozzle arrangement 10 according to the invention is shown mounted in the ceiling 7 of the drying chamber 2. However, a plurality of nozzle arrangements 10 may be provided in the ceiling 7. Alternatively, or additionally, the spray drying apparatus may be provided with one or more nozzle arrangements in the walls 6,8 of the upper and lower parts, respectively, of the drying chamber 2.

Referring now to Figs. 2 to 7 for a more detailed description of the nozzle arrangement, the nozzle arrangement 10 includes a nozzle lance 11 and a nozzle 12, the nozzle being indicated only schematically (cf. Figs. 5 to 7). The nozzle lance 11 extends from an upstream end 11a to a downstream end lib, the nozzle 12 being positioned at the downstream end lib. The nozzle 12 may e.g. be a two-fluid nozzle as described in Applicant's published international application No. WO 2005/061119 (Niro), the contents of which are incorporated herein by reference, a pressure nozzle, or any other kind of nozzle, in which regulation of the nozzle axis is required. At the upstream end 11a, the nozzle lance 11 has a connection piece 13 for connection with the supply pipe 3 for the liquid feed to be atomised. The nozzle 12 and hence the nozzle lance 11 have a longitudinal axis 14 defining an axial direction. In most applications, the nozzle arrangement is positioned in such a way that the longitudinal axis is positioned substantially vertically.

The nozzle lance 11 is connected with the ceiling or wall con- cerned of the spray drying apparatus 1 by means of a securing device generally designated 20. The securing device 20 comprises adjustment means for shifting the longitudinal axis 14 of the nozzle 12 as will be described in further detail below. The adjustment means include a first adjustment disk 21 and a second adjustment disk 22 connected with each other in a releasable manner at a plurality of angular positions relative to each other. Each adjustment disk 21, 22 has an aperture 21a, 22a (cf. Fig. 3) extending in the axial direction and accommodating the nozzle lance 11. In the embodiment shown, the first adjustment disk 21 is connected with a flange 23 which is formed integrally with a tube part 24 having a connection piece 25 adapted to be connected with a supply pipe (not shown) for gas. The tube part 24 is, in turn, connected with a second tube part 26 and a third tube part 27. The nozzle lance 11 is guided through an aperture 27a in the third tube part 27 such that the nozzle lance 11 may be displaced along the longitudinal axis by means of adjustment means to be described in detail further on. The nozzle lance 11 is furthermore guided by means of a centring flange 28 cooperating with the inner walls of the second tube part 26. Eventually, a base disk 29 is connected with the second adjustment disk 22 at the side thereof facing away from the first adjustment disk 21. The side of the base disk 29 facing away from the second adjustment disk 22 forms an abutment surface of the nozzle arrangement with the wall of the drying chamber of the spray drying apparatus. The base disk 29 is formed integrally with a tube 40 extending from the base disk 29 towards the downstream end lib of the nozzle lance 11. A plurality of ring seals and/or grooves for accommodating such ring seals are indicated by reference numerals 30 to 36.

As is shown most clearly in Fig. 3, the connection piece 25 adapted to be connected with a supply tube for gas is positioned eccentrically with respect to the nozzle lance 11 and hence to the longitudinal axis 14 of the nozzle 12. The tube part 24 is in fluid connection with the tube 40 surrounding the nozzle lance 11. The gas is preferably as a conditioning gas flowing in the space between the tube 40 and the nozzle lance 11. The gas may be any suitable kind of gas, such as air, nitrogen etc., including or excluding vapour of the solvent used. The gas may be partially or fully saturated. The conditioning gas may be utilized to influence the droplets coming out of the nozzle 12, such that the droplets are for instance moved to a desired location in the drying chamber 2. Furthermore, the conditioning gas may be utilized to cool or heat the nozzle in order to prevent deposits etc. The velocity of the conditioning gas is relatively low and lies in the interval 5 to 10 m/s, preferably 6 to 8 m/s. The nozzle arrangement is designed for approximately 1 bar above atmospheric pressure. As the conditioning gas is introduced eccentrically via the connection piece 25, a vortex is formed in the space between the tube 40 and the nozzle lance 11. In order to suppress the vortex before the conditioning gas emerges from the tube 40, a plurality of vanes 37 (cf. Fig. 5) is positioned near the downstream end lib of the nozzle lance 11.

The configuration of the adjustment disks 21 and 22 will now be described with particular reference to Fig. 4. As shown in Fig. 4, the first adjustment disk 21 has a cross-section in a radial direction transverse to the axial direction, which tapers at an angle α from one peripheral point 211 to a diametrically opposite peripheral point 212. The cross- section of the first adjustment disk 21 thus forms a trapezoid having bases bi and b₂ and legs Ii and I₂. The angles of the trapezoid shape may, in principle, be arbitrary, for instance isosceles; however, it is preferable that the angles between the leg I₂ and the bases bi and b₂ are substantially 90°. Similarly, the second adjustment disk 22 has an angle of taper β and the cross-section of the second adjustment disk 22 thus forms a trapezoid having bases Bi and B₂ and legs Li and L₂. Also in this adjustment disk 22, the angles of the trapezoid shape may, in principle, be arbitrary, for instance isosceles; however, it is preferable that the angles between the leg L₂ and the bases Bi and B₂ are substantially 90°. The angle of taper α, β of each of the first and second adjustment disks 21, 22 lies in the interval 0 to 5°. Preferably, the angles of taper of the first 21 and the second adjustment disk 22 are identical. In this embodiment, it is thus possible to attain a position of the adjustment disks 21, 22 relative to each other, in which the legs I₂ and L₂ are parallel with each other, as the angles of taper α, β compensate for each other. It is to be understood that as each of the lines referred to in the above represents a line in a three-dimensional body, for instance the term "leg I₁" is a line positioned in the plane defined by the downstream face of the first adjustment disk 21, i.e. the side facing the second adjustment disk 22.

The releasable connection between the first and second adjustment disks 21, 22 in a plurality of angular positions relative to each other is obtained in the following way: The first adjustment disk 21 is, along a circumference 214, provided with a plurality of axially extending apertures 213, in the embodiment shown six apertures, for accommodation of fastening means in the form of for instance screw bolts (not shown) adapted to cooperate with apertures 223 in the second adjustment disk 22. The circumference 214 may be positioned at a suitable distance from the outer rim of the first adjustment disk 21. The number of these apertures may vary according to i.a. the dimensions of the nozzle arrangement, preferably however, there are four to eight such apertures. As it is possible to rotate the first adjustment disk 21 relative to the second adjustment disk 22 to an arbitrary position and then apply the fastening means in corresponding apertures 213 and 223, an adjustment of the inclination of the longitudinal axis 14 of the nozzle 12 is attained. As an example, Fig. 5 corresponds to the mutual positioning of the adjustment disks 21, 22 shown in Fig. 4. By rotating the first adjustment disk 21 through substantially 180°, such that the longer bases bi and B₂ are brought into line with each other, the position shown in Fig. 6 is attained, in which the longitudinal axis 14 has been tilted through an angle substantially corresponding to the sum of the angles of taper α and β. In order to obtain an even finer adjustment of the angular position and thus of the inclination of the longitudinal axis, the apertures 213 in the first adjustment disk 21 may, as shown, be formed as a slot extending in the direction of the circumference chosen. The apertures 223 in the second adjustment disk 22 are formed in a suitable manner, e.g. as threaded holes for the reception of fastening means in the form of threaded screw bolts. A marking on each adjustment disk preferably indicates the particular angular position chosen of the adjustment disks 21, 22 relative to each other. In the embodiment shown, the marking on the first adjustment disk 21 is a scale 215 on the edge surface of the first adjustment disk 21, and the marking on the second adjustment disk is an indication in the form of a numbered line 225 on the top surface of the second adjustment disk 22, i.e. on the surface facing the edge surface of the first adjustment disk 21. The markings may take any suitable form and may be positioned arbitrarily on the first and second adjustment disks 21, 22. For instance, instead of the shown millimetre scale 215 and the number 225, a series of symbols, numbers or lettering may be utilized.

Turning now to the connection between the second adjustment disk 22 and the base disk 29, reference is in particular made to Figs. 2 and 3. Along a circumference 227 the second adjustment disk 22 is provided with a plurality of axially extending apertures 226. In the embodiment shown, there are six apertures equally distributed along the circumference 227 for accommodation of fastening means (not shown) adapted to cooperate with apertures 296 in the base disk 29. Depending on i.a. the dimensions of the nozzle arrangement there may be e.g. four to eight apertures. By positioning the second adjustment disk 22 in an arbitrary angular position with respect to the base disk 29 it is possible to obtain a three-dimensional shift in the position of the longitudinal axis 14 of the nozzle 12 along a cone defined by the inclination determined by the adjustment of the first and second adjustment disks 21, 22 relative to each other.

As a further feature in the adjustment of the longitudinal axis, it is possible to position the second adjustment disk 22 in a plurality of positions transversely relative to the axial direction defined by the longitudinal axis. In the embodiment shown, this is attained by forming each of the apertures 226 in the second adjustment disk 22 as a long hole extending in a direction transversely to the axial direction. The corresponding apertures 296 in the base disk may be formed in any suitable manner, e.g. as threaded holes for the reception of a threaded screw bolt (not shown). The adjustment disk 22 may thus be displaced in these long holes 226, as is indicated in Fig. 7. In order to make it possible to retain information regarding the position of the adjustment disks 21, 22 relative to the base disk 29 in the direction transversely to the axial direction, the position is preferably indicated by markings on the second adjustment disk 22 and on the base disk 29. In the embodiment shown, the marking on the second adjustment disk 22 is a scale 228 on the top of the second adjustment disk 22, and the marking on the base disk 29 is a numbered line 298 on the top surface of the base disk. As in the case of the markings on the first and second adjustment disks 21, 22, these markings may take any suitable form and be positioned arbitrarily.

Eventually, means for adjusting the position of the nozzle lance 11 in the axial direction is provided. In the embodiment shown, these means comprises an adjusting screw device generally designated 275. The position of the nozzle lance 11 in the axial direction is indicated by a marking in the form of a scale 115 on the nozzle lance 11.

In order to retain information of the position of the respective parts of the adjustment means of the securing device, the markings may indicate a combination of numbers and/or lettering providing an unambiguous code for each position of the longitudinal axis of the nozzle.

The nozzle arrangement and its mounting in a spray drying apparatus thus comprises the steps of determining a desired position of the longitudinal axis of the nozzle, and adjusting the adjustment means according to the desired position. The position may then be recreated by reading the markings indicating the position of the longitudinal axis of the nozzle. This eases assembling of the parts in a correct manner after cleaning in between periods of production. The invention should not be regarded as being limited to the embodiment shown and described in the above but various modifications and combinations of features may be carried out without departing from the scope of the following claims.

Claims

C L A I M S

1. A nozzle arrangement for a spray drying apparatus, comprising a nozzle lance, a nozzle having a longitudinal axis defining an axial direction, and a securing device adapted to secure the nozzle lance to a ceiling or wall of a drying chamber of the spray drying apparatus, c h a r a c t e r i z e d in that the securing device comprises adjustment means including at least a first and a second adjustment disk releasably connected with each other, said adjustment means being adapted to shift the longitudinal axis of the nozzle.

2. A nozzle arrangement according to claim 1, wherein each of the first and second adjustment disks has a cross-section in at least one radial direction transverse to said axial direction, which cross-section tapers at an angle from one peripheral point to a diametrically opposite peripheral point, the first and second adjustment disks being adapted to be releasably connected with each other in a plurality of angular positions relative to each other.

3. A nozzle arrangement according to claim 2, wherein the angle of taper of each of the first and second adjustment disks lies in the interval 0 to 5°.

4. A nozzle arrangement according to claim 3, wherein the angles of taper of the first and the second adjustment disk are identical.

5. A nozzle arrangement according to any one of claims 2 to 4, wherein the first adjustment disk along a circumference is provided with a plurality of axially extending apertures, preferably four to eight apertures, most preferably six apertures, for accommodation of fastening means adapted to cooperate with apertures in the second adjustment disk.

6. A nozzle arrangement according to claim 5, wherein each said axially extending aperture in the first adjustment disk is a slot extending in the direction of said circumference.

7. A nozzle arrangement according to any one of claims 2 to 6, wherein the angular position of the adjustment disks relative to each other is indicated by a marking on each adjustment disk.

8. A nozzle arrangement according to claim 7, wherein the marking on the first adjustment disk is a scale on the edge surface of the first adjustment disk, and the marking on the second adjustment disk is an indication, preferably in the form of a number and/or lettering on the top surface of the second adjustment disk.

9. A nozzle arrangement according to any one of claims 1 to 8, wherein the securing device furthermore includes a base disk adapted to be secured to a ceiling or wall of the drying chamber, the second adjustment disk being adapted to be connected with the base disk, the first adjustment disk being connected with the nozzle lance via a flange.

10. A nozzle arrangement according to claim 9, wherein the second adjustment disk along a circumference is provided with a plurality of axially extending apertures, preferably four to eight apertures, most preferably six apertures, for accommodation of fastening means adapted to cooperate with apertures in the base disk.

11. A nozzle arrangement according to claim 10, wherein at least the second adjustment disk is adapted to be connected with the base disk in a plurality of positions transversely relative to the axial direction, each of the apertures in the second adjustment disk being formed as a long hole extending in a direction transversely to the axial direction.

12. A nozzle arrangement according to any one of claims 9 to 11, wherein the position of the adjustment disks relative to the base disk in the direction transversely to the axial direction is indicated by markings on the second adjustment disk and on the base disk.

13. A nozzle arrangement according to claim 12, wherein the marking on the second adjustment disk is a scale on the top or edge surface of the second adjustment disk, and the marking on the base disk is a number and/or lettering on the top surface of the base disk.

14. A nozzle arrangement according to any one of claims 1 to 13, wherein means for adjusting the position of the nozzle lance in the axial direction is provided.

15. A nozzle arrangement according to claim 14, wherein said means comprises an adjusting screw device.

16. A nozzle arrangement according to claim 14 or 15, wherein the position of the nozzle lance in the axial direction is indicated by a marking in the form of a scale on the nozzle lance.

17. A nozzle arrangement according to any one of claims 7 to 16, wherein the markings indicate a combination of numbers and/or lettering providing an unambiguous code for each position of the longitudinal axis of the nozzle.

18. A nozzle arrangement according to any one of the preceding claims, wherein the nozzle arrangement further includes a tube for gas surrounding said nozzle lance.

19. A nozzle arrangement according to claim 18, wherein the space formed between the tube and the nozzle lance is adapted to receive a conditioning gas.

20. A nozzle arrangement according to claim 19, wherein a connection piece adapted to be connected with a supply pipe for the conditioning gas is positioned eccentrically with respect to the longitudinal axis of the nozzle.

21. A nozzle arrangement according to claim 20, wherein a plurality of vanes is positioned near a downstream end of the nozzle lance.

22. A nozzle arrangement according to claim 20 or 21, wherein the velocity of the conditioning gas lies in the interval 5 to 10 m/s, preferably 6 to 8 m/s.

23. A nozzle arrangement according to any one of the preceding claims, wherein the nozzle arrangement is designed for approximately 1 bar above atmospheric pressure.

24. A method of mounting a nozzle arrangement according to any one of claims 1 to 23 in a ceiling or wall of a spray drying apparatus, comprising the steps of: determining a desired position of the longitudinal axis of the nozzle, adjusting the adjustment means according to the desired position.

25. The method of claim 24, wherein the nozzle arrangement comprises markings to indicate the position of the longitudinal axis of the nozzle, further comprising the step of reading the markings.