REFRACTOMETER

Abstract

The present disclosure embodies a refractometer that includes an embodied fitting to the standardized probe with the optical structure to facilitate refractometer optics to the probe tip.

Claims

1. A refractometer comprising a probe tip diameter of ½″ or 12 mm.

2. The refractometer according to claim 1, wherein the refractometer comprises at least one of the following: a prism, fitting to a probe having a tip diameter of 12 mm or ½″. at least one light source, a condenser lens, a collimator lens, a prism seal, an imaging device and an interface to peripheral devices to communicate with the refractometer.

3. The refractometer of claim 1, wherein the refractometer is a process refractometer adapted to industrial temperature measurement by the probe taking the shape with the measures of a thermowell.

4. The refractometer according to claim 1, wherein the prism has a circular brim, to fit the inner diameter of ½″ or 12 mm probe.

5. The refractometer according to claim 1, wherein the prism is mounted into the tip of the refractometer, the prism mirror stretching from the prism's seal to the brim.

6. The refractometer according to claim 1, wherein the prism has a mirror that has a mirror surface angle to the symmetry axis that is at half the steepest measurement angle (α), to direct the reflected rays to leave the prism surface at a right angle parallel to the probe tip pipe inner wall.

7. The refractometer according to claim 1, wherein the refractometer comprises an objective lens in position to create an optical image in a plane perpendicular to the axis of the prism, where the rays of the same measurement angle are focused on a given point of the image.

8. The refractometer according to claim 1, wherein the refractometer comprises such a light source condenser lens that has conical sides to fit closely to the bore of the probe.

9. The refractometer according to claim 1, wherein the refractometer comprises rod-lenses in a plurality of lenses arranged one after the other for transmitting the optical image outside the narrow probe.

10. The refractometer according to claim 1, wherein the refractometer is adapted so as to be suitable for use with an available pharmaceutical retraction device for 12 mm diameter probe.

11. A method for carrying out a pharmaceutical process, wherein the method comprises providing the refractometer of claim 1, installing the refractometer by a standard pH connector, and applying the refractometer to the pharmaceutical process.

12. The refractometer of claim 2, wherein the refractometer is a process refractometer adapted to industrial temperature measurement by the probe taking the shape with the measures of a thermowell.

13. The refractometer according to claim 2, wherein the prism has a circular brim, to fit the inner diameter of ½″ or 12 mm probe.

14. The refractometer according to claim 3, wherein the prism has a circular brim, to fit the inner diameter of ½″ or 12 mm probe.

15. The refractometer according to claim 2, wherein the prism is mounted into the tip of the refractometer, the prism mirror stretching from the prism's seal to the brim.

16. The refractometer according to claim 3, wherein the prism is mounted into the tip of the refractometer, the prism mirror stretching from the prism's seal to the brim.

17. The refractometer according to claim 4, wherein the prism is mounted into the tip of the refractometer, the prism mirror stretching from the prism's seal to the brim.

18. The refractometer according to claim 2, wherein the prism has a mirror that has a mirror surface angle to the symmetry axis that is at half the steepest measurement angle (α), to direct the reflected rays to leave the prism surface at a right angle parallel to the probe tip pipe inner wall.

19. The refractometer according to claim 3, wherein the prism has a mirror that has a mirror surface angle to the symmetry axis that is at half the steepest measurement angle (α), to direct the reflected rays to leave the prism surface at a right angle parallel to the probe tip pipe inner wall.

20. The refractometer according to claim 4, wherein the prism has a mirror that has a mirror surface angle to the symmetry axis that is at half the steepest measurement angle (α), to direct the reflected rays to leave the prism surface at a right angle parallel to the probe tip pipe inner wall.

Description

SHORT DESCRIPTION OF FIGS

[0047] FIGS. 1 to 10 illustrate background techniques as such and the optical aspects thereof as such. In the following, embodiments of the present invention are disclosed with reference to the FIGS. 11 to 18, in which

[0048] FIG. 11 illustrates an example of a prism of an embodied refractometer optics, in combination to one or more embodiments,

[0049] FIG. 12 illustrates ray path example in an embodied prism, in combination to one or more embodiments,

[0050] FIG. 13 illustrates further ray path examples about angles of reflected rays, in combination to one or more embodiments,

[0051] FIG. 14 illustrates objective lens in duty according to an embodied refractometer, in combination to one or more embodiments,

[0052] FIG. 15 illustrates a condenser lens example of an embodied refractometer, in combination to one or more embodiments,

[0053] FIG. 16 illustrates an embodied example of an embodied refractometer system, comprising an embodied refractometer and a certified device to remove a 12 mm probe from the process line, in combination to one or more embodiments,

[0054] FIG. 17 illustrates total optics in an embodied refractometer, in combination to one or more embodiments,

[0055] FIGS. 18a, 18b and 18c illustrate examples on thermowell probe geometries as such.

DETAILED DESCRIPTION OF EMBODIMENT EXAMPLES OF THE PRESENT DISCLOSURE

[0056] According to an embodiment of the present disclosure, the design goal has been made by the prism of a refractometer optics as exemplified in FIG. 10, as comprising a large prism as possible in a 12 mm probe. It means that the prism has fit snugly into the bore of the thermowell or a similar probe.

[0057] That structure sets the design condition on the prism that the brim is advantageously circular with the same diameter as the inner diameter of the pipe according to FIG. 11. Moreover, the efficient mirror area is advantageous to have maximized. That is, the effective mirror area is limited by the prism seal in one end, and by the brim of the prism in the other end.

[0058] But it's not only the prism that have to fit into the bore, that goes also for the whole optics as well (FIG. 17), in contrast to FIG. 10. That is, no incoming or outgoing light rays may bend outwards from the prism brim. And the lenses must stay inside the bore, too. In FIG. 17 embodiment example the optical axis of the lenses shown (collimator, condenser and objective) are tilted in respect to the probe longitudinal central axis, the last mentioned being in alignment in an embodiment with (straight) probe walls of the 12 mm or ½″ probe.

[0059] To stay within the probe pipe, the rays with the steepest measurement angle α as illustrated in FIG. 12, are critical. When the mirror surface angle to the symmetry axis is at half the steepest angle, the reflected rays leaves the prism surface at a right angle parallel to the pipe inner wall. For greater angles, the reflected rays turn away from the wall. The relation between the respective refractive indices (RI, sample and prism):

sin(α)=RI.sub.sample/RI.sub.prism  (2)

[0060] The equation (2) shows that the steepest angle corresponds to the smallest RI to be measured from the sample.

[0061] FIG. 13 exemplifies the angles reflected from two points on the prism's wetted surface. The measurement range is indicated: The steepest angle represents the lowest measured RI value, limited by the brim of the prism. The lowest angle represents the highest measured RI value, limited by the prism seal. The optics forming the optical image by the objective lens is no longer as simple and regular as in FIG. 10.

[0062] The objective lens must create an optical picture in a plane perpendicular to the axis of the prism, where the rays of the same measurement angle are focused on its own point of the image. In fact, no ordinary spherical lens can do that. The shape of both of the convex surfaces must be precisely calculated, and the lens must be cast to its special form (FIG. 14).

[0063] The light source optics is made with two lenses as in FIG. 10, the convex surfaces of the lenses are spherical, as normally. But the condenser lens is otherwise special (FIG. 15) in embodiments, because it must have conical sides to fit closely to the bore of the probe. Then it handles also the light rays entering the prism adjacent to the inner pipe wall. The collimator lens is merely a standard planoconvex lens from a catalogue. The condenser, the collimator and the light source have the same tilted axis in common (FIG. 17). As the measured sample is a thin film of process liquid on the prism window surface, the refractometer can be sensitive to fouling. If there is a layer of impurities on the prism window, the refractometer measures the impurities, instead of the process liquid. In most applications, a prism cleaning nozzle is installed close to the prism, blowing steam or water on the surface.

[0064] In e.g., pharmaceutical fermentation, no cleaning medium is allowed into the process liquid.

[0065] In that case, a 12 mm diameter probe has an additional advantage as it can be used by an existing retraction device. An insertion device can will be used to withdraw the probe tip into an internal chamber where it is isolated from the process liquid (FIG. 16). Steam blows in at B, air for drying at A, blow-out at C. Such an embodied refractometer with its probe is embodied as a refractometer system having a retraction device with its pneumatic cylinder.