APPARATUS, PROCESS AND USE

Abstract

A scraped surface heat exchanger comprising a heat exchange surface, a rotatable shaft, said shaft having at least one mounting means, and a sweeping element wherein said sweeping element comprises, a blade having at least one aperture for engaging with the mounting means such that the sweeping element is connected to the mounting means and characterised in that when the rotatable shaft is rotating relative to the heat exchange surface the sweeping element has substantially no movement relative to the rotating shaft and said sweeping element has substantially no contact with the inner surface of the heat exchanger.

Claims

1. A scraped surface heat exchanger comprising: a heat exchange surface, a rotatable shaft, the shaft having at least one mounting member, and a sweeping element comprising a blade having at least one aperture for engaging with the mounting member such that the sweeping element is connected to the mounting member, when the rotatable shaft rotates relative to the heat exchange surface the sweeping element has substantially no movement relative to the rotating shaft and the sweeping element has substantially no contact with the inner surface of the heat exchanger.

2. A scraped surface heat exchanger according to claim 1 wherein the sweeping element comprises a blade having a leading edge with a distance of 0.05 mm to 10 mm from the inner surface of the heat exchanger.

3. A scraped heat exchanger according to claim 1 wherein the mounting member comprises at least one engagement member, the engagement member comprises a projection extending outwardly at a substantially right angle to the rotatable shaft for engagement with the sweeping element so as to engage the sweeping element such that the sweeping element is connected to the mounting member wherein when the rotatable shaft is rotating relative to the heat exchange surface the sweeping element has substantially no movement relative to the rotating shaft and the sweeping element has substantially no contact with the inner surface of the heat exchanger.

4. A scraped heat exchanger according to claim 1 wherein the projection is a substantially T-shaped element extending outwardly at a substantially right angle to the rotatable shaft for engagement with the sweeping element.

5. A scraped heat exchanger according to claim 1 wherein the rotatable shaft comprises a rotational speed of from 350 and 1000 ppm.

6. A sweeping element comprising a blade having an edge for sweeping contact with a heat exchange surface wherein the blade comprises at least one aperture for engaging with a mounting member such that the blade is connected to the mounting member, when the rotatable shaft rotates relative to the heat exchange surface the sweeping element has substantially no movement relative to the rotating shaft and the sweeping element has substantially no contact with the inner surface of the heat exchanger.

7. A sweeping element according to claim 6 wherein the sweeping element comprises a blade having a plurality of substantially T-shaped apertures longitudinally arranged through the blade body for engaging with the mounting member.

8. A sweeping element according to claim 7 wherein the substantially T-shaped apertures are linearly arranged adjacent between 2 and 10 mm from the trailing edge of the blade.

9. A scraped heat exchanger according to claim 1 wherein substantially T-shaped element extend outwardly at a substantially right angle to the rotatable shaft and engage with the sweeping element comprising a blade having a plurality of mating substantially T-shaped apertures longitudinally arranged through the blade body such that the blade is connected to the substantially T-shaped element.

10. (canceled)

11. A method for preparing a food product by heating or cooling and agitating a mixture in a scraped surface heat exchanger comprising a heat exchange surface, a rotatable shaft, the shaft having at least one mounting member, and a sweeping element wherein the sweeping element comprises a blade having at least one aperture for engaging with the mounting member such that the sweeping element is connected to the mounting member and when the rotatable shaft rotates relative to the heat exchange surface the sweeping element has substantially no movement relative to the rotating shaft and said sweeping element has substantially no contact with the inner surface of the heat exchanger.

12. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0100] FIG. 1 is a perspective view illustrating the overall appearance of a scraped-surface heat exchanger according to one embodiment of the present invention.

[0101] FIG. 2 is a more detailed partially sectional view of a scraped surface heat exchanger according to one embodiment of the present invention

[0102] FIG. 3 is a perspective view of a blade according to one embodiment of the present invention.

[0103] FIG. 4a is an elevational view of a T-shaped element relative to the rotatable shaft and a blade with a T-shaped aperture according to one embodiment of the invention.

[0104] FIG. 4b is as FIG. 4a but showing an elevational view of a blade locked into position on to the surface of the heat exchanger according to one embodiment of the invention.

[0105] FIG. 5 is a perspective view illustrating the overall appearance of a scraped-surface heat exchanger according to another embodiment of the present invention.

[0106] FIG. 6 is a view of a blade showing wear and burnt product accumulation.

EXAMPLES AND FURTHER EMBODIMENTS

[0107] As illustrated in FIG. 1 a preferred embodiment of the present invention provides a scraped surface heat exchanger comprising a cylindrical chamber having a heat exchange surface (4) through which a mixture is caused to travel. This chamber is surrounded by a jacket (X) through which a heating or cooling means may be circulated which provides heat exchange by a usual heat exchange process. At one end of the chamber is provided an inlet (X) and at its opposite end is an outlet (X) through which the mixture may pass. Inside the chamber a rotatable shaft (2) is rotatably mounted and on the rotatable shaft a longitudinal blade (3) for sweeping mixtures is securely mounted.

[0108] FIG. 2 illustrates a preferred embodiment of the present invention wherein the blade (3) with a non-contacting blade edge (X) is at a distance away from the inner surface of the heat exchange surface (X). The rotatable shaft (2) and the inner surface of the heat exchange surface (X) are defining an annular space (X) therein.

[0109] FIG. 2a illustrates a preferred embodiment of the present invention wherein the blade (3) with a blade edge (X) bearing on the inner surface of the heat exchange surface (X). The rotatable shaft (2) and the inner surface of the heat exchange surface (X) are defining an annular space (X) therein

[0110] FIG. 3 is showing the geometry of a preferred embodiment of the blade (3) according to the present invention. The blade comprising a plurality of substantially T-shaped apertures (X) longitudinally arranged through the blade body for engaging with the mounting means (1).

[0111] FIGS. 4a and 4b illustrates how the blade (3) is attached to the rotatable shaft (2). The blade (3) is offered to the mounting means (1) such that the mounting means on the shaft can pass through the blade until the blade rests on the broadest planar surface of the mounting means. The blade is then slid in a direction parallel to the rotatable shaft's main axis until the aperture in the blade aligns with the projected mounting means. A fixing bolt is inserted and tightened.

[0112] FIG. 5 is a photograph of a heat exchanger according to another embodiment of the present invention

[0113] FIG. 6 shows a damaged scraper blade from a prior art heat exchanger, where the blade is not arranged in the manner described herein for heat exchangers of the invention and thus scrapes the inner surface of the heat exchanger and moves tangentially and radially relative to the shaft.

[0114] According to the present invention a ‘scraped surface heat exchanger’ includes any heat exchanger comprising a heat exchange surface, a rotatable shaft and a sweeping element. In one embodiment the scraped surface heat exchanger may be a non-cylindrical heat exchanger such as oval shaped. In a preferred embodiment the scraped surface heat exchanger is a cylindrical heat exchanger.

[0115] Preferably according to the invention the rotatable shaft may be mounted concentrically or eccentrically to the heat exchanger, more preferably the rotatable shaft is preferably mounted concentrically relative to the cylindrical heat exchanger.

[0116] As used herein, the rotatable shaft is defined as a revolving rod that transmits rotational motion. In a preferred embodiment of the invention the rotatable shaft bears at least one mounting means for engaging with the scraping element, preferably between 3 and 15 mounting means for engaging with the scraping element, more preferably between 5 and 10 mounting means for engaging with the scraping element.

[0117] According to another preferred embodiment of the present invention the rotatable shaft has an optimal rotational speed of from 350 and 1000 rpm, more preferably from 400 to 800 rpm, even more preferably between 500 and 700 rpm, most preferably from 550 to 650 rpm, for example from 575 to 625 rpm, e.g. about 600 rpm.

[0118] A further aspect of the invention comprises a method of operating a heat exchanger of the invention as described herein, in which the shaft is a rotatable shaft; the method comprising the step of rotating the shaft at a rotational speed as given herein.

[0119] As used herein, substantially no movement is defined as no movement, preferably as locked against moment, more preferably as no radial and no tangential movement of the blades relative to the rotatable shaft.

[0120] As used herein, substantially no contact is defined as no contact, or no scraping contact or non-touching or no touching.

[0121] As used herein sweeping element is defined as a blade, preferably a blade having a leading edge wherein leading edge having no direct contact with the inner surface of the heat exchanger or even more preferably a blade having a leading edge with a distance of 0.05 mm to 10 mm, preferably 0.1 mm to 8 mm, more preferably 0.2 to 5 mm from the inner surface of the heat exchanger.

[0122] Preferably according to the present invention, the sweeping element comprises blades having as more preferably between 95 to 99% of the time, more preferably 100% of the time no movement relative to the rotatable shaft, when the rotatable shaft is rotating relative to the heat exchange surface.

[0123] Preferably according to the present invention, the sweeping element comprises blades having as more preferably between 95 to 99% of the time, more preferably 100% of the time no contact with the inner surface of the heat exchanger, when the rotatable shaft is rotating relative to the heat exchange surface.

[0124] Preferably in one embodiment of the present invention the sweeping element comprises at least one blade having a leading edge with a distance of 0.1 mm to 10 mm, preferably 0.1 mm to 5 mm, more preferably 0.2 to 3 mm, most preferably 0.25 to 2 mm from the inner surface of the heat exchanger.6

[0125] Preferably according to the invention the mounting means comprises at least one engagement means so as to engage the scraping element, preferably the mounting means comprises between 3 and 15 engagement means, more preferably between 5 and 10 engagement means.

[0126] In a preferred embodiment of the invention the engagement means comprises a projection extending outwardly at a substantially right angle to the rotatable shaft for engagement with the sweeping element.

[0127] In a preferred embodiment the engagement means is a projection wherein said projection is a substantially T-shaped element.

[0128] In a preferred embodiment of the invention the engagement means comprises a substantially T-shaped element extending outwardly at a substantially right angle to the rotatable shaft for engagement with the sweeping element.

[0129] In one embodiment of the present invention the substantially T-shaped element extending outwardly at a substantially right angle to the rotatable shaft is suitable for engagement with a sweeping element wherein said sweeping element comprises a blade having a plurality of mating substantially T-shaped apertures longitudinally arranged through the blade body.

[0130] In one embodiment of the present invention the substantially T-shaped element extending outwardly at a substantially right angle to the rotatable shaft are suitable for engagement with a sweeping element wherein said sweeping element comprises a blade having a plurality of mating substantially T-shaped apertures longitudinally arranged through the blade body such that the blade is connected to the substantially T-shaped element characterised in that when the rotatable shaft is moving in periodic motion (preferably rotating) relative to the heat exchange surface the sweeping element has substantially no contact with the inner surface of the heat exchanger.

[0131] In a preferred embodiment of the invention the substantially T-shaped element extending outwardly at a substantially right angle to the rotatable shaft engages with a blade having a plurality of mating substantially T-shaped apertures such that when the rotatable shaft is rotating relative to the heat exchange surface the sweeping element is substantially locked against movement relative to the rotatable shaft and said sweeping element has substantially no contact with the inner surface of the heat exchanger.

[0132] In a preferred embodiment of the invention the substantially T-shaped element extending outwardly at a substantially right angle to the rotatable shaft engages with a blade having a plurality of mating substantially T-shaped apertures such that when the rotatable shaft is rotating relative to the heat exchange surface the sweeping element is substantially locked against movement relative to the rotatable shaft and said sweeping element is not touching the inner surface of the heat exchanger.

[0133] In a preferred embodiment of the invention the substantially T-shaped element extending outwardly at a substantially right angle to the rotatable shaft engages with a blade having a plurality of mating substantially T-shaped apertures such that when the rotatable shaft is rotating relative to the heat exchange surface the sweeping element is substantially locked against movement relative to the rotatable shaft and said sweeping element is clear of the inner surface of the heat exchanger.

[0134] Preferably according to the invention the sweeping element comprises a blade having a plurality of apertures longitudinally arranged through the blade body for engaging with the mounting means.

[0135] More preferably according to the invention the sweeping element comprises a blade having a plurality of substantially T-shaped apertures longitudinally arranged through the blade body for engaging with the mounting means.

[0136] Preferably, the apertures are proximate to the trailing edge of the blade, said apertures being linearly arranged adjacent to the trailing edge of the blade.

[0137] Preferably, the apertures are substantially T-shaped and are proximate to the trailing edge of the blade, said substantially T-shaped apertures being linearly arranged adjacent to the trailing edge of the blade.

[0138] More preferably, the substantially T-shaped apertures are linearly arranged between 2 and 10 mm, preferably 3 and 8 mm, more preferably 5 to 7 mm from the trailing edge of the blade.

[0139] In a preferred embodiment the apertures comprise a longitudinal portion having between 10 and 30 mm, preferably 15 and 25 mm and more preferably 17 and 20 mm in length.

[0140] Preferably the T-shaped aperture comprises a vertical section having a width of between 3 and 15 mm, preferably 5 and 10 mm, most preferably between 6 and 8 mm.

[0141] Preferably the T-shaped aperture comprises a horizontal section, perpendicular to the rotatable shaft having a width 30 and 50 mm, preferably 20 and 40 mm and more preferably 15 and 20 mm.

[0142] Preferably according to the invention the sweeping element comprises a blade, preferably an elongated blade, more preferably a plurality of elongated blades.

[0143] Suitable materials for use as a blade include metal preferably steel or any polymeric material.

[0144] As used herein, substantially no contact is defined as no contact, or no scraping contact or non-touching or no touching or non-scraping

[0145] As used herein, substantially no movement is defined as no movement, preferably as locked against moment, more preferably as no radial and no tangential movement of the blades relative to the rotatable shaft.

[0146] As used herein non pivotal connection is defined as connection whereby there is no tangential or radial movements relative to the connection point.

[0147] Preferably according to the invention there is no tangential movement of the blade relative to the rotatable shaft.

[0148] Preferably according to the invention there is no radial movement of the blade relative to the rotatable shaft.

[0149] As used here herein substantially right angle is defined as 90 degrees.

[0150] A preferred embodiment of the present invention also relates to a sweeping element for use in a scraped-surface heat exchanger wherein said sweeping element comprises at least one aperture for engaging with the mounting means such that the sweeping element is connected to the mounting means and characterised in that when the rotatable shaft is rotating relative to the heat exchange surface the sweeping element has substantially no movement relative to the rotating shaft and said sweeping element has substantially no contact with the inner surface of the heat exchanger.

[0151] A preferred embodiment of the present invention also relates to a method for preparing a food product by heating and agitating a mixture in a scraped surface heat exchanger comprising a heat exchange surface, a rotatable shaft, said shaft having at least one mounting means, and a sweeping element wherein said sweeping element comprises, a blade having at least one aperture for engaging with the mounting means such that the sweeping element is connected to the mounting means and characterised in that when the rotatable shaft is rotating relative to the heat exchange surface the sweeping element has substantially no movement relative to the rotating shaft and said sweeping element has substantially no contact with the inner surface of the heat exchanger

[0152] A preferred embodiment of the present invention also relates to a method for preparing a food product by cooling and agitating a mixture in a scraped surface heat exchanger comprising a heat exchange surface, a rotatable shaft, said shaft having at least one mounting means, and a sweeping element wherein said sweeping element comprises, a blade having at least one aperture for engaging with the mounting means such that the scraping element is connected to the mounting means and characterised in that when the rotatable shaft is rotating relative to the heat exchange surface the sweeping element has substantially no movement relative to the rotating shaft and said sweeping element has substantially no contact with the inner surface of the heat exchanger.

[0153] A method according to the present invention wherein said food product may include, confectionery or fat based product or beverages such as coffee, tea or ice cream confectionery or dairy products or bakery products.

[0154] More preferably method for preparing a confectionery product by heating and agitating a chocolate mixture in a scraped surface heat exchanger comprising a heat exchange surface, a rotatable shaft, said shaft having at least one mounting means, and a sweeping element wherein said sweeping element comprises, a blade having at least one aperture for engaging with the mounting means such that the sweeping element is connected to the mounting means and characterised in that when the rotatable shaft is rotating relative to the heat exchange surface the sweeping element has substantially no movement relative to the rotating shaft and said sweeping element has substantially no contact with the inner surface of the heat exchanger.

[0155] More preferably method for preparing a confectionery product by cooling and agitating a chocolate mixture in a scraped surface heat exchanger comprising a heat exchange surface, a rotatable shaft, said shaft having at least one mounting means, and a scraping element wherein said scraping element comprises, a blade having at least one aperture for engaging with the mounting means such that the scraping element is connected to the mounting means and characterised in that when the rotatable shaft is rotating relative to the heat exchange surface the sweeping element has substantially no movement relative to the rotating shaft and said sweeping element has substantially no contact with the inner surface of the heat exchanger.

[0156] The many features and advantages of the invention are apparent from the detailed specification and it is intended by the appended claims to cover all such features and advantages of the invention which fall within the spirit and scope of the invention. Further since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.