Method of spray-drying and apparatus for spray-drying

Patent metadata

Field	Value
Publication number	US-9573104-B2
Application number	US-201214239154-A
Country	US
Kind code	B2
Filing date	Aug 15, 2012
Priority date	Aug 16, 2011
Publication date	Feb 21, 2017
Grant date	Feb 21, 2017

Abstract

Method of spray-drying a high-viscosity fluid, e.g. comprising a food product. The method comprises providing a nozzle plate wherein at least one nozzle is provided, said nozzle plate having an inner main surface and an outer main surface. The method comprises providing the high-viscosity fluid in a reservoir that is in fluidum connection with the at least one nozzle. The method comprises pressurizing the high-viscosity fluid in the reservoir, wherein the fluid flows, as a result of said pressurizing, towards the nozzle plate, thus creating a pressure difference over the at least one nozzle so that the fluid flows out of the at least one nozzle, thereby passing the outer main surface after passing the inner main surface. A cross-sectional area of the at least one nozzle in the inner main surface exceeds a cross-sectional area of the at least one nozzle in the outer main surface.

First claim

The invention claimed is:

1. Method of spray-drying a high-viscosity fluid using a spraying device, the method comprising:
providing a nozzle plate wherein at least one nozzle is provided, said nozzle plate having an inner main surface and an outer main surface, the at least one nozzle extending through the nozzle plate from the inner main surface to the outer main surface;
providing the high-viscosity fluid in a reservoir that is in fluidum connection with the at least one nozzle;
pressurizing the high-viscosity fluid in the reservoir, wherein the fluid flows, as a result of said pressurizing, towards the nozzle plate, thus creating a pressure difference over the at least one nozzle so that the fluid flows out of the at least one nozzle, thereby passing the outer main surface after passing the inner main surface; wherein the fluid flowing out of the nozzle forms a jet that breaks up into droplets; and
at least partially drying the droplets in a drying medium, to become particles;
wherein a cross-sectional area of the at least one nozzle in the inner main surface exceeds a cross-sectional area of the at least one nozzle in the outer main surface thereby decreasing a pressure difference over the at least one nozzle needed for spraying the high-viscosity fluid, and
wherein an area ratio, being equal to the cross-sectional area of the at least one nozzle in the inner main surface divided by the cross-sectional area of the at least one nozzle in the outer main surface, is at least five.

2. Method according to claim 1 , wherein the area ratio is at most fifty.

3. Method according to claim 1 , wherein the at least one nozzle comprises a substantially non-widening part that extends from the outer main surface, and comprises a substantially widening part that extends from the substantially non-widening part to the inner main surface.

4. The method of claim 3 , wherein the substantially non-widening part is cylindrical and the substantially widening part is frustoconical.

5. Method according to claim 3 , wherein a pressure difference ratio, being equal to a pressure difference over the substantially widening part divided by a pressure difference over the substantially non-widening part, is at most 1.

6. The method of claim 5 , wherein the pressure difference ratio is at most 0.5.

7. Method according to claim 1 , wherein, during pressurizing, the pressure difference over the at least one nozzle is kept at at most 15 bar.

8. The method of claim 7 , wherein the pressure difference over the at least one nozzle is kept at at most 12 bar.

9. Method according to claim 1 , further comprising the step of generating dynamic pressure variations in the fluid near the nozzle that propagate through the nozzle and cause a controlled breakup of the fluid jet flowing out of the nozzle, the broken up fluid jet forming substantially mono-disperse droplets.

10. The method of claim 1 , wherein the drying medium is air.

11. Apparatus for spray-drying of a high-viscosity fluid, the apparatus comprising:
a reservoir for containing the high-viscosity fluid;
a nozzle plate that is in fluidum connection with the reservoir, has an inner main surface and an outer main surface, and is provided with at least one nozzle extending through the nozzle plate from the inner main surface to the outer main surface; and
drying means;
the apparatus being arranged for pressurizing the fluid in the reservoir so that, in use, the fluid flows towards the nozzle plate, thus creating a pressure difference over the at least one nozzle so that the fluid flows out of the at least one nozzle, thereby passing the outer main surface after passing the inner main surface; wherein the fluid flowing out of the nozzle forms a jet that breaks up into droplets; wherein the drying means is arranged for causing and/or allowing the droplets to dry to become particles
wherein a cross-sectional area of the at least one nozzle in the inner main surface exceeds a cross-sectional area of the at least one nozzle in the outer main surface thereby decreasing a pressure difference over the at least one nozzle needed for spraying the high-viscosity fluid, and
wherein an area ratio, being equal to the cross-sectional area of the at least one nozzle in the inner main surface divided by the cross-sectional area of the at least one nozzle in the outer main surface, is at least five.

12. Apparatus according to claim 11 , wherein the area ratio is at most fifty.

13. Apparatus according to claim 12 , wherein the at least one nozzle comprises a substantially non-widening part that extends from the outer main surface, and comprises a substantially widening part that extends from the substantially non-widening part to the inner main surface.

14. The apparatus of claim 13 , wherein the substantially non-widening part is cylindrical and the substantially widening part is frustoconical.

15. Apparatus according to claim 12 , wherein a length of the substantially non-widening part of the at least one nozzle, measured along an outflow direction of the high-viscosity fluid through said non-widening part, is at least equal to three times a diameter of the at least one nozzle in the outer main surface.

16. Apparatus according to claim 11 , comprising pressurizing means for pressurizing the fluid in the reservoir so that the fluid flows towards the nozzle plate and out of the at least one nozzle, thereby passing the outer main surface after passing the inner main surface.

17. Apparatus according to claim 16 , wherein the pressurizing means are arranged for keeping a pressure difference over the at least one nozzle at at most 15 bar.

18. The apparatus of claim 17 , wherein the pressure difference over the at least one nozzle is kept at at most 12 bar.

19. Apparatus according to claim 11 , further comprising a pressure varying means in the fluid near the nozzle, the pressure varying means arranged for generating dynamic pressure variations in the fluid near the nozzle that propagate through the nozzle and cause a controlled breakup of the fluid jet flowing out of the nozzle, the broken up fluid jet forming substantially mono-disperse droplets.

20. Apparatus according to claim 11 , wherein the pressure varying means comprises a pressure focusing member arranged such that an end of the pressure focusing member facing the nozzle is placed at a distance of 2-1000 μm from the outflow opening and wherein the pressure focusing member and/or the nozzle plate are arranged for vibrating with respect to each other for varying the pressure adjacent the outflow opening.

Assignees

• Rijfers Andries
• Brouwers Leonardus Antonius Maria
• Houben René Jos
• Koldeweij Robin Bernardus Johannes
• Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno

Inventors

• Rijfers Andries
• Brouwers Leonardus Antonius Maria
• Houben René Jos
• Koldeweij Robin Bernardus Johannes

Classifications

• B01J2/04 Primary

  in a gaseous medium {(if combined with suspending the material in a gas, e.g. fluidised beds B01J2/16)} · CPC title

• B01J2/18

  using a vibrating apparatus · CPC title

• B05B1/04

  in flat form, e.g. fan-like, sheet-like · CPC title