Tapered throttling valve

1. A throttling valve comprising:

a valve housing ( 21 ) including a fluid inlet ( 29 ) and a fluid outlet ( 27 );

a perforated sleeve ( 323 ) axially arranged within the valve housing about a central axis ( 11 ) extending from the fluid inlet ( 29 ) to the fluid outlet ( 27 ) such that a flow path from the fluid inlet to the fluid outlet passes from an outside of the perforated sleeve to an inside of the perforated sleeve, the perforated sleeve ( 323 ) having a plurality of openings ( 330 );

wherein a flux of a fluid stream flowing via the flow path from the fluid inlet ( 29 ) to the fluid outlet ( 27 ) is controllable via the plurality of openings ( 330 ) of the perforated sleeve which, in use, create a pressure reduction over the throttling valve and thereby a cooling effect of the fluid stream,

wherein each of the openings ( 330 ) widens from the outside of the perforated sleeve ( 323 ) to the inside of the perforated sleeve ( 323 ) in a downstream direction of the flow path along longitudinal axes ( 12 ) of the openings ( 330 ); and

wherein the longitudinal axes ( 12 ) of the openings ( 330 ′″) have a substantial axial component relative to the central axis.

2. The throttling valve according to claim 1 , wherein the openings ( 330 ) have a divergent angle φin the range 10°-50°.

3. The throttling valve according to claim 1 , wherein the throttling valve further comprises a piston type valve body ( 22 ), the piston type valve body ( 22 ) being slideably arranged with respect to the perforated sleeve ( 323 ), to control the flux of the fluid stream through the openings ( 330 ).

4. The throttling valve according to claim 1 , wherein the openings ( 330 ′) have a substantial radial orientation with respect to a central axis of the perforated sleeve ( 3 ).

5. The throttling valve according to claim 1 , wherein longitudinal axes ( 12 ) of the openings ( 330 ″) have a substantial tangential component relative to a central axis of the perforated sleeve ( 323 ).

6. The throttling valve according to claim 1 , wherein the longitudinal axes ( 12 ) of the openings ( 330 ″″) have a substantial tangential component relative to a central axis of the perforated sleeve ( 323 ) and a substantial axial component relative to a central axis of the perforated sleeve ( 323 ).

7. The throttling valve according to claim 1 , wherein the axial component of the longitudinal axes ( 12 ) is at an angle α with respect to a central axis 11 of the throttling valve which is in the range 20°<α<70°, or in the range 20°<α<30°.

8. The throttling valve according to claim 1 , wherein the interior surface of the openings ( 330 , 330 ′, 330 ″, 330 ′″, 330 ″″) having an average surface roughness (Ra) below 2 micron.

9. The throttling valve according to claim 8 wherein the interior surface of the openings ( 330 , 330 ′, 330 ″, 330 ′″, 330 ″″) exerts a water contact angle hysteresis below 25°.

10. The throttling valve according to claim 9 wherein the interior surface is coated with a Diamond Like Carbon layer with a layer thickness of more than 3 micron.

11. The throttling valve according to claim 10 wherein the Diamond Like Carbon layer comprises one or more of the bonds Carbon-Fluor, Carbon-Silicon, Carbon-Oxygen, Carbon-Hydrogen.

12. A method for controlling flux of a fluid stream, the method comprising:

providing a fluid stream to a fluid inlet of a throttling valve including a valve housing defining a flow path extending from the fluid inlet to a fluid outlet, and a perforated shield axially arranged about a central axis of the valve housing extending between the fluid inlet and the fluid outlet such that a flow path from the fluid inlet to the fluid outlet passes from an outside of the perforated sleeve to an inside of the perforated sleeve; and

operating the throttling valve to control the flux of the fluid stream via the flow path,

wherein a plurality of openings of the perforated shield create a pressure reduction over the throttling valve and thereby a cooling effect on the fluid stream,

wherein each of the openings widens from the outside of the perforated sleeve to the inside of the perforated sleeve and in a downstream direction of the flow path along longitudinal axes ( 12 ) of the openings ( 330 );

wherein the longitudinal axes of the openings have a substantial axial component relative to a central axis of the perforated sleeve.

13. A throttling valve comprising:

a valve housing having a fluid inlet and a fluid outlet;

a flow path through the valve housing extending from the fluid inlet to the fluid outlet; and

a perforated sleeve axially arranged within the flow path about a central axis of the valve housing extending from the fluid inlet to the fluid outlet such that the flow path from the fluid inlet to the fluid outlet passes from an outside of the perforated sleeve to an inside of the perforated sleeve and including a plurality of openings adapted to create a pressure reduction over the throttling valve to thereby cool a fluid stream moving along the flow path from the fluid inlet to the fluid outlet;

wherein the width of each of the openings widens from the outside of the perforated sleeve to the inside of the perforated sleeve and in a downstream direction of the flow path along longitudinal axes ( 12 ) of the openings ( 330 ); and

wherein the longitudinal axes of the openings have a substantial axial component relative to a central axis of the perforated sleeve.

14. The throttling valve of claim 13 , wherein the openings have a divergent angle φin the range of 10° to 50°.

15. The throttling valve of claim 13 , further comprising a piston type valve body slideably arranged with respect to the perforated sleeve to control the flux of the fluid stream through the openings.

16. The throttling valve of claim 13 , wherein the openings have a substantial radial orientation with respect to a central axis of the perforated sleeve.

17. The throttling valve of claim 13 , wherein an interior surface of the openings is coated with a Diamond-like carbon layer with a layer thickness of more than 3 micron.