WO2017153944A1

WO2017153944A1 - Degerminator

Info

Publication number: WO2017153944A1
Application number: PCT/IB2017/051389
Authority: WO
Inventors: Charl Marais; Christian George Frederick Richter
Original assignee: Roff Industries (Pty) Ltd.
Priority date: 2016-03-10
Filing date: 2017-03-09
Publication date: 2017-09-14
Also published as: ZA201803338B

Abstract

A degerminator for treating grain kernels is disclosed. The degerminator (10) includes an inner member (22) and an outer member (12) which are relatively rotatable about an axis of rotation (X) and which define between them a treatment chamber (32). An outer surface (34) of the inner member (22) and an inner surface (36) of the outer member (12) are provided with a plurality of axially offset spaced apart protrusions (42, 44).

Description

DEGERMINATOR

FIELD OF THE INVENTION

This invention relates, broadly, to degerminators. More particularly, the invention relates to a degerminator for treating grain kernels and to a method of treating grain kernels.

BACKGROUND OF THE INVENTION

A kernel of maize can be regarded as being generally constituted of endosperm, germ and skin. The skin, when the endosperm and germ have been liberated therefrom, is commonly referred to as bran.

It is typically desirable to separate the germ and skin from the endosperm in a process known as degermination. Degermination can be performed prior to or as an initial step in maize processing where the maize endosperm or starch has to be separated from the skin and maize germ. Applications include, but are not limited to, maize milling, processing of maize starch, brewery grits and ethanol plants.

In this specification, the term "degerminator" is used to refer to an apparatus used for separating the germ, endosperm and/or skin of grain, in particular maize kernels, but also other products, such as wheat. The term "product" is used to refer to kernels and/or components of kernels which have been treated by a degerminator or which have been fed into a degerminator and are in the process of being treated. Various types of degerminators have been developed over the years. In one configuration, a treatment chamber is formed between a rotor, which is mounted to a shaft for rotation about an axis, and a stator in the form of a stationary housing. The treatment chamber is typically annular in cross-section.

The rotor and stator may have irregular opposed surfaces so as to define rough surfaces in the treatment chamber. In use, these surfaces impede motion of the product as it turns in and moves through the treatment chamber. The germ is typically dislodged from the endosperm by impact and/or friction as kernels rub against each other and against surfaces of the treatment chamber.

It is desirable to procure particles of endosperm that are largely free of skin and germ. It is also desirable to recover as much as possible of the endosperm from the kernels fed into the degerminator. While known degerminators may effectively remove the skin from a kernel, the Inventors have found that the roughness of surfaces in the treatment chamber can be destructive to kernels. In particular, when removing the germ and skin, relatively large portions of the endosperm may also be removed. As a result, a significant portion of the endosperm of kernels fed into the degerminator may be lost.

The Inventors have identified a need for a degerminator which alleviates these and other problems, at least to some extent.

SUMMARY OF INVENTION

According to one aspect of the invention, there is provided a degerminator for treating grain kernels, in particular maize, comprising an inner member and an outer member which are relatively rotatable about an axis of rotation and which define between them a treatment chamber, wherein an outer surface of the inner member and an inner surface of the outer member are provided with a plurality of axially offset spaced apart protrusions, and wherein at least some of the protrusions have a radial dimension of not less than 15 mm.

Free ends of at least some of the protrusions of the inner member may radially overlap with free ends of at least some of the protrusions of the outer member.

In some embodiments, at least some of the protrusions of the inner member may substantially or entirely radially overlap with at least some of the protrusions of the outer member.

The inner member may be a rotor and the outer member may be a stator. The rotor may define a plurality of spaced apart rotary protrusions, while the stator defines a plurality of spaced apart stationary protrusions.

The rotor may be mounted to a shaft for rotation about the axis of rotation. The stator may be provided by a housing of the degerminator.

The outer surface of the inner member and the inner surface of the outer member may be opposing surfaces that are generally concentric about the axis of rotation. In such cases, the treatment chamber is generally annular in cross section.

The protrusions may be generally rectangular with reference to the cross section of the degerminator. The protrusions may be provided with rounded edges.

As mentioned above, at least some of the protrusions have a radial dimension of not less than 15 mm. In some embodiments, more than 75% or substantially all of the protrusions may have a radial dimension of not less than 15 mm. An axial spacing may be defined between adjacent protrusions of the inner member and outer member which permits the protrusions to pass one another with clearance as the inner member and outer member rotate relative to one another. The axial spacing may be 10 mm or more.

A first radial spacing may be defined between the inner surface of the outer member and a free end of each protrusion of the inner member. A second radial spacing may be defined between the outer surface of the inner member and a free end of each protrusion of the outer member. The first radial spacing may be identical or substantially similar to the second radial spacing. The radial spacings may be identical or substantially similar in size to the axial spacing.

According to another aspect of the invention there is provided a degerminator for treating grain kernels, in particular maize, comprising: an inner member; an outer member, the inner and outer members being relatively rotatable about an axis of rotation; a feed chamber; and a treatment chamber in flow communication with the feed chamber, wherein the feed chamber includes at least one guide vane which is mounted about the inner member to form a generally helical feed arrangement for operatively urging product in a feed direction, and wherein a helix angle of the at least one guide vane varies along at least part of a length of the feed chamber.

The feed chamber and the treatment chamber may be axially arranged between the inner and outer members. The feed direction may be defined along the axis of rotation.

The inner member may be a rotor and the outer member may be a stator. A plurality of guide vanes may be provided which are separated by gaps located between ends of adjacent guide vanes in the feed arrangement.

The helix angle of the at least one guide vane may gradually increase in the feed direction. The helix angle may increase from a starting helix angle of between 30 and 60 degrees (inclusive), preferably about 45 degrees, to an ending helix angle which is greater than 60 degrees and less than or equal to 90 degrees, preferably about 75 degrees.

According to a further aspect of the invention there is provided a degerminator for treating grain kernels, in particular maize, comprising: an inner member; an outer member, the inner and outer members being relatively rotatable about an axis of rotation and defining between them a treatment chamber, the outer member further defining one or more treatment chamber outlets at a discharge end thereof; and a choking arrangement including: one or more choking elements, each choking element being in axial alignment with one of the treatment chamber outlets, wherein an outlet zone is defined between each choking element and its respective treatment chamber outlet; and an adjustment mechanism coupled to the choking elements which is configured to permit the choking elements to be moved axially towards or away from the treatment chamber outlets, thereby to adjust axial lengths of the outlet zones.

A plurality of treatment chamber outlets may be provided, each having a corresponding choking element. The choking elements may be positioned in an outlet chamber which is configured operatively to receive product discharged from the treatment chamber via the treatment chamber outlets.

The inner member may be a rotor and the outer member may be a stator. The stator may be provided by a housing of the degerminator.

The outer member may define two treatment chamber outlets. The treatment chamber may be generally annular in cross section, with the outlets evenly spaced apart about the axis of rotation.

The outer member may be provided with a plurality of screening openings shaped and dimensioned operatively to permit product in the form of germ and/or bran to be discharged from the treatment chamber. The screening openings may be provided in a lower region of the outer member, upstream from the treatment chamber outlets with reference to the feed direction.

According to an even further aspect of the invention there is provided a degerminator for treating grain kernels, in particular maize, comprising an inner member and an outer member which are relatively rotatable about an axis of rotation and which define between them a treatment chamber, wherein an outer surface of the inner member and an inner surface of the outer member are provided with a plurality of axially offset spaced apart protrusions, and wherein free ends of at least some of the protrusions of the inner member radially overlap with free ends of at least some of the protrusions of the outer member.

As mentioned above, the degerminator may in particular be for treating maize. In other embodiments, the degerminator may be a degerminator for treating wheat. The invention extends to a method of treating grain kernels, in particular maize, comprising the steps of: relatively rotating an inner member and an outer member of a degerminator as hereinbefore described; feeding grain kernels into the treatment chamber of the degerminator under pressure; and discharging product from the treatment chamber.

The step of feeding kernels into the treatment chamber may include feeding the kernels into the treatment chamber via a feed chamber as hereinbefore described.

The method may include the step of using the choking arrangement as hereinbefore described to move the choking elements axially towards or away from the treatment chamber outlets, thereby to regulate the pressure inside the treatment chamber and/or a flow rate of product discharged from the treatment chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be further described, by way of example, with reference to the accompanying drawings.

In the drawings:

FIG. 1 shows a perspective view of an embodiment of a degerminator according to the invention;

FIG. 2 shows a side view of the degerminator of FIG. 1 ; FIG. 3 shows another perspective view of the degerminator of FIG. 1 , wherein a rear section thereof is not shown in order to illustrate a choking arrangement;

FIG. 4 shows a sectional side view of the degerminator of FIG. 1 ; FIG. 5 shows a further side view of the degerminator of FIG. 1 , wherein a portion of a housing thereof is not shown in order to illustrate a feed arrangement;

FIG. 6 shows a sectional view of the degerminator of FIG. 1 , taken along the line A-A in FIG. 4; FIG. 7 shows a sectional view of the degerminator of FIG. 1 , taken along the line B-B in FIG. 4;

FIG. 8 shows a sectional view of the degerminator of FIG. 1 , taken along the line C-C in FIG. 4;

FIG. 9 shows an adjuster of the degerminator of FIG. 1 ; and FIG. 10 shows components of the adjuster of FIG. 9;

FIG. 11 shows a perspective view of a degerminator according to the invention including a further exemplary outlet configuration and choking arrangement according to the invention;

FIG. 12 shows another perspective view of the degerminator of FIG. 1 1 ; FIG. 13 shows a sectional side view of the degerminator of FIG. 1 1 ;

FIG. 14 shows an end view of the degerminator of FIG. 1 1 , wherein a portion of the degerminator is not shown in order better to illustrate the outlet configuration and choking arrangement;

FIG. 15 shows an end view of the degerminator of FIG. 1 1 , wherein a portion of the degerminator is not shown in order better to illustrate the outlet configuration and choking arrangement;

FIG. 16 shows an end view of the degerminator of FIG. 1 1 , wherein a portion of the degerminator is not shown in order better to illustrate the outlet configuration and choking arrangement; FIG. 17 shows a perspective view of a choking element of the degerminator of FIG. 1 1 ;

FIG. 18 shows a top view of the choking element of FIG. 17; and FIG. 19 shows a rear view of the choking element of FIG. 17.

DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS

In Figures 1 to 10, reference numeral 10 generally indicates an embodiment of a degerminator according to the invention. The degerminator 10 is configured to treat maize by separating the endosperm, germ and/or skin of maize kernels.

Referring to Figures 1 to 3, the degerminator 10 includes an outer member in the form of a housing 12 having an inlet end 14 and a discharge end 16. An inlet 18 is defined near the inlet end 14. The housing 12 comprises a plurality of annular segments which have complementary flanges 15 which are bolted together. It should be noted that, in other embodiments, the housing may be provided by a single unit and not by a plurality of segments.

An outlet section 20 is mounted to the housing 12 at its discharge end 16.

Referring now also to Figures 4 to 6, the degerminator 10 further includes an inner member in the form of a rotor 22 located inside the housing 12 and mounted to a shaft 24 for operative rotation about an axis of rotation "X", which is shown in Figures 2 to 4. The rotor 22 is mounted to the shaft 24 between bearings 26, 28 for rotation together with the shaft 24 about the axis X.

The housing 12 and rotor 22 are relatively rotatable about the axis X. The housing 12 thus operatively acts as a stator. A feed chamber 30 (Figure 4) and a treatment chamber 32, which are axially spaced apart and in flow communication with each other, are defined between an outer surface 34 of the rotor 22 and a generally concentric inner surface 36 of the housing 12. The feed chamber 30 and treatment chamber 32 are generally annular in cross section.

Referring to Figures 4 and 5, a plurality of guide vanes 37 are mounted about the rotor 22 within the feed chamber 30 to form a generally helical feed arrangement 38 for operatively urging product in a feed direction. The feed direction is defined along the axis X in the direction indicated by the arrow Ύ" in Figures 4 and 5.

Adjacent guide vanes 37 are slightly offset and are separated by gaps 40 located between ends of adjacent guide vanes 37. The feed arrangement 38 has a varying helix angle a. In the illustrated embodiment, and as can be seen in Figure 5 of the drawings, the helix angle a of the guide vanes 37 gradually increases in the feed direction Y. More specifically, a starting helix angle a is approximately 45 degrees, and this gradually increases to an ending helix angle a of approximately 75 degrees. The Inventors have found that the starting helix angle causes kernels to be fed relatively aggressive into the feed chamber 30, while the gradual increase in helix angle maintains a high pressure as well as effective product flow in the treatment chamber 32. This ensures that product cannot easily return or flow upstream once pressure is applied thereto, in use.

In the treatment chamber 32, the outer surface 34 of the rotor 22 and the inner surface 36 of the housing 12 are provided with a plurality of spaced apart protrusions 42, 44, respectively. In use, with the rotor 22 rotating about the axis X, the protrusions 42 on the rotor 22 will thus rotate while the protrusions 44 on the housing 12 will be stationary. Accordingly, the protrusions on the rotor 22 are hereinafter referred to as rotary protrusions 42 and the protrusions on the housing 12 are hereinafter referred to as stationary protrusions 44. The protrusions 42, 44 are generally rectangular with reference to the cross section of the degerminator 10 and have rounded edges. Free ends of the rotary protrusions 42 radially overlap with free ends of the stationary protrusions 44, as is best illustrated in Figure 6. In other words, the radial outer ends of the rotary protrusions 42 are spaced further from the axis X than the radially inner ends of the stationary protrusions 44.

In this embodiment, the protrusions 42, 44 are circular cylindrical in shape and have and have a radial dimension of 20 mm.

As can be seen in Figure 4, an axial spacing exists between adjacent rotary protrusions 42 and stationary protrusions 44. In this embodiment, the axial spacing between adjacent rotary and stationary protrusions is 10 mm. A first radial spacing is defined between the inner surface 36 and free ends of the rotary protrusions 42 and a second radial spacing is defined between the outer surface 34 and free ends of the stationary protrusions 44. In this embodiment, the first and second radial spacings are equal, both being 10 mm. It is envisaged that when wheat is treated instead of maize, the radial spacings will be approximately 1 .5 times the grain diameter.

The housing 12 includes, in a lower region thereof, a plurality of circumferentially spaced screening openings 46. The screening openings 46 are located near the discharge end 16 and are shaped and dimensioned operatively to permit product in the form of germ and/or bran to be discharged from the treatment chamber 32.

The housing 12 further includes three treatment chamber outlets 48 provided in an end wall 49 at the discharge end 16 of the housing 12, as is best illustrated in Figures 6 to 8. The treatment chamber outlets 48 have an arcuate shape and are evenly spaced apart about the axis X. The outlet section 20 defines an outlet chamber 50 (Figure 4) which is configured operatively to receive product discharged from the treatment chamber 32 via the treatment chamber outlets 48. The outlet section also defines a degerminator outlet 51 .

A choking arrangement 52 is provided in the outlet chamber 50 and is configured to restrict the flow of product through the treatment chamber outlets 48 and to enable the pressure inside the treatment chamber 32 to be controlled, in use.

The choking arrangement 52 includes three choking elements 54 and an adjustment mechanism coupled to the choking elements 54.

Referring to Figures 3, 4 and 8, each choking element 54 is of similar cross sectional shape to and in axial alignment with one of the treatment chamber outlets 48. An outlet zone 56 is formed between each choking element 54 and its respective outlet 48. The choking elements 54 are shaped and positioned to be parallel with the end wall 49 such that each outlet zone 56 has a uniform axial length which extends between the choking element 54 and its respective treatment chamber outlet 48.

The choking elements 54 are mounted to a plate member 56. The plate member 56 is coupled to the adjustment mechanism which is configured to move the plate member 56, and thus also the choking elements 54, in an axial direction. The adjustment mechanism includes links 58 which are mounted to a pair of upper fixed brackets 60 and a pair of lower fixed brackets 62. The links 58 are rotatably mounted between the upper fixed brackets 60, which are mounted to a wall of the outlet section 20, and the lower fixed brackets 62, which are mounted to the plate member 56. The links are mounted on shafts 64 which extend between the brackets 60, 62, as is best shown in Figure 3. The adjustment mechanism further includes an adjuster 64. The adjuster 64 includes a rotatable shaft 68 which is coupled to one of the links 58 by a coupling 66, as shown in Figure 3.

Referring to Figures 9 and 10, the adjuster 64 includes a housing 70 which is mounted to an exterior of the outlet section 20. The shaft 68 is rotatably mounted to the housing 70 at a first end 72 thereof and another shaft 74 is rotatably mounted to the housing 70 at a second end 76 thereof.

A gear 78 is mounted to the shaft 68 at the first end 72 of the housing 70. The gear 78 is operatively driven by a pinion 80, which in turn is mounted onto the shaft 74 at the second end 76 of the housing 70. A knob 82 and a ratchet 84 are also mounted to the shaft 74 at the second end 76 of the housing 70.

A threaded ball spring plunger 86 interacts with the ratchet 84 to restrict the turning action of the knob 82, in use.

In use, and as mentioned above, the degerminator 10 is operable to treat maize. The rotor 22 is rotated and maize kernels are fed into the degerminator 10 via the inlet 18.

Maize kernels enter the feed chamber 30 and the guide vanes 37 urge product from the inlet 18 in the feed direction into the treatment chamber 32. The varying helix angle of the feed arrangement 38 ensures that product is moved away from the inlet 18 and increasingly pressurised as it moves towards the treatment chamber 32.

In the treatment chamber 32, motion of product is impeded as it turns in and moves through the treatment chamber 32 under pressure. The skin and germ is dislodged from the endosperm by impact and/or friction as kernels rub against each other and against surfaces of the treatment chamber 32.

The Inventors have found that the spacing between protrusions, the radial dimension of the protrusions and/or the radial overlap between rotary and stationary protrusions cause product to follow a crooked or at least non-linear path through the treatment chamber 32.

Product is discharged from the treatment chamber 32 via the treatment chamber outlets 48, and at least some germ and bran is discharged from the degerminator 10 via the screening openings 46.

By manually turning the knob 24 of the choking arrangement 52, the shaft 23 is driven, which in turn causes the choking elements 54 to be moved axially towards or away from the treatment chamber outlets 48. In this way, the pressure inside the treatment chamber 32 and/or the flow of product discharged from the treatment chamber can be regulated.

Figures 1 1 to 17 illustrate a degerminator 90 which includes another example of an outlet configuration and choking arrangement according to the invention.

The degerminator 90 includes a conventional inlet 94, housing 96 and treatment chamber 98, which will be well understood by those of ordinary skill in the art.

Whereas the degerminator 10 of Figures 1 to 10 includes three treatment chamber outlets spaced evenly about the axis X, the housing 96 of the degerminator 90 provides only two treatment chamber outlets 100 leading into its outlet chamber 102. The outlets 100 have an arcuate shape and are provided on opposite sides of the axis of rotation Z, which is shown in Figures 12 and 13. The Inventors have found that the use of a two treatment chamber outlet design is particularly effective when using the degerminator 90 of the type shown in Figures 1 1 to 19. The Inventors have also found that three treatment chamber outlets can be used if capacity is to be increased.

The outlet chamber 102 is also provided with a choking arrangement 92 configured to restrict the flow of product through the treatment chamber outlets 100 and to enable the pressure inside the treatment chamber 98 to be controlled, in use. The choking arrangement 92 includes two choking elements 104 and an adjustment mechanism coupled to the choking elements 104.

As is the case in the embodiment of Figures 1 to 10, the choking elements 104 are shaped and positioned to be aligned with a corresponding treatment chamber outlet 100. In this example, the choking elements 104 are arcuate in shape but slightly smaller than the treatment chamber outlets 100 when the degerminator 90 is considered in end view, i.e. the angular extent of the treatment chamber outlets 100 is greater than that of the choking elements 104. This is best shown in Figures 14 and 16. The Inventors have found that the use of choking elements that are slightly smaller than their corresponding treatment chamber outlets may improve the general efficiency of the degerminator and/or the pressure regulating capabilities of the choking arrangement.

One of the choking elements 104 is illustrated in greater detail in Figures 17 to 19. The choking element 104 includes an arcuate body 1 12 with 45 degree bevelled front edge regions 1 13, and a generally planar connecting plate 1 14 at its rear. In this case, therefore, an outlet zone of irregular axial length is defined between each choking element 104 and its corresponding treatment chamber outlet 100. The Inventors have found that the use of choking elements with bevelled or rounded front edge regions may in some applications improve the general efficiency of the degerminator and/or the pressure regulating capabilities of the choking arrangement. The adjustment mechanism includes an adjustable knob 106 which is attached to a threaded bar 108. The adjustment mechanism further includes an axially displaceable connecting element 1 10. The bar 108 extends parallel to the axis Z and is drivingly connected to the connecting element 1 10, while the choking elements 104 are in turn fixedly secured to the connecting element 1 10 by their connecting plates 1 14.

In use, by manually turning the knob 106 of the choking arrangement 92, the bar 108 is driven, which in turn causes the connecting element 1 10 and the choking elements 104 to be displaced axially towards or away from the treatment chamber outlets 100. In this way, the pressure inside the treatment chamber 98 and/or the flow of product discharged from the treatment chamber can be regulated.

As mentioned above, it is desirable to recover as much as possible of the endosperm from the kernels fed into a degerminator. The Inventors believe that the degerminator of the present invention may be less destructive to kernels than known degerminators and may thus reduce the portion of endosperm that is lost during degermination, particularly as a result of the flow path caused by the arrangement and/or radial dimensions of protrusions in the treatment chamber.

The Inventors also believe that the feeding arrangement and choking arrangement as described above may improve the control of or the obtained pressure and/or flow in a degerminator.

Although the invention has been described with particular reference to the degermination of maize kernels, it will be appreciated that it may also be applied in the degermination of other kernels. For instance, the degerminator may be configured to treat wheat. It will be understood that while wheat does not have

"germ" in the way as that maize has, embodiments of the present invention may be used to remove some of or all of the bran from the endosperm in wheat. It is believed that this may serve to increase capacity of a wheat mill.

The preceding description of an embodiment of the invention is provided as an enabling teaching of the invention. Those skilled in the relevant art will recognise that many changes can be made to the embodiments described, while still attaining the beneficial results of the present invention. It will also be apparent that some of the desired benefits of the present invention can be attained by selecting some of the features of the present invention without utilising other features. Accordingly, those skilled in the art will recognise that modifications and adaptations to the present invention are possible and can even be desirable in certain circumstances, and are a part of the present invention. The description is therefore provided as illustrative of the principles of the present invention and not as a limitation thereof.

Claims

1 . A degerminator for treating grain kernels, the degerminator including an inner member and an outer member which are relatively rotatable about an axis of rotation and which define between them a treatment chamber, wherein an outer surface of the inner member and an inner surface of the outer member are provided with a plurality of axially offset spaced apart protrusions, and wherein at least some of the protrusions have a radial dimension of not less than 15 mm.

2. The degerminator according to claim 1 , wherein free ends of at least some of the protrusions of the inner member radially overlap with free ends of at least some of the protrusions of the outer member.

3. A degerminator for treating grain kernels, the degerminator including an inner member and an outer member which are relatively rotatable about an axis of rotation and which define between them a treatment chamber, wherein an outer surface of the inner member and an inner surface of the outer member are provided with a plurality of axially offset spaced apart protrusions, and wherein free ends of at least some of the protrusions of the inner member radially overlap with free ends of at least some of the protrusions of the outer member.

4. The degerminator according to any one of the preceding claims, wherein free ends of substantially all of the protrusions of the inner member radially overlap with free ends of substantially all of the protrusions of the outer member.

5. The degerminator according to any one of the preceding claims, wherein the inner member is a rotor and the outer member is a stator, wherein the rotor is mounted or mountable to a shaft for rotation about the axis of rotation, and wherein the inner surface of the outer member and the outer surface of the inner member oppose each other and are generally concentric about the axis of rotation.

6. The degerminator according to any one of the preceding claims, wherein at least some of the protrusions have rounded edges.

7. The degerminator according to any one of the preceding claims, wherein a radial dimension of more than 75% of the protrusions is not less than 15 mm.

8. The degerminator according to any one of the preceding claims, wherein an axial spacing is defined between each pair of adjacent protrusions of the inner member and outer member, and wherein the axial spacing between each pair of adjacent protrusions is at least 10 mm.

9. The degerminator according to any one of the preceding claims, wherein a first radial spacing is defined between the inner surface of the outer member and a free end of each protrusion of the inner member, wherein a second radial spacing is defined between the outer surface of the inner member and a free end of each protrusion of the outer member, and wherein the first radial spacing and the second radial spacing are substantially similar in size.

10. The degerminator according to any one of the preceding claims, further including a feed chamber in flow communication with the treatment chamber, wherein the feed chamber includes at least one guide vane which is mounted about the inner member to form a generally helical feed arrangement for operatively urging product in a feed direction, and wherein a helix angle of the at least one guide vane varies along at least part of a length of the feed chamber.

1 1 . The degerminator according to claim 10, wherein the at least one guide vane is a plurality of guide vanes that are separated by gaps located between ends of adjacent guide vanes.

12. The degerminator according to claim 10 or 1 1 , wherein the helix angle of the at least one guide vane gradually increases in the feed direction, from a starting helix angle which is between 30 degrees and 60 degrees (inclusive) to an ending helix angle which is greater than 60 degrees and less than or equal to 90 degrees.

13. The degerminator according to any one of the preceding claims, wherein the outer member further defines one or more treatment chamber outlets at a discharge end thereof, and wherein the degerminator further includes a choking arrangement including:

one or more choking elements, each choking element being in axial alignment with one of the treatment chamber outlets, wherein an outlet zone is defined between each choking element and its respective treatment chamber outlet; and

an adjustment mechanism coupled to the choking elements which is configured to permit the choking elements to be moved axially towards or away from the treatment chamber outlets, thereby to adjust axial lengths of the outlet zones.

14. The degerminator according to claim 13, wherein the one or more treatment chamber outlets is a plurality of treatment chamber outlets, each having a corresponding choking element.

15. The degerminator according to claim 14, wherein the treatment chamber is generally annular, and wherein the treatment chamber outlets have a generally arcuate shape and are evenly spaced about the axis of rotation.

16. The degerminator according to claim 15, wherein the outer member includes two treatment chamber outlets and the choking arrangement includes two choking elements.

17. The degerminator according to any one of claims 13 to 16, wherein the choking elements are positioned in an outlet chamber which is configured operatively to receive product discharged from the treatment chamber via the treatment chamber outlets.

18. The degerminator according to any one of claims 13 to 17, wherein the outer member is provided with a plurality of screening openings located operatively upstream from the treatment chamber outlets, wherein the screening openings are shaped and dimensioned operatively to permit product to be discharged from the treatment chamber.

19. The degerminator according to any one of the preceding claims, wherein the outer member is a housing of the degerminator.

20. A degerminator for treating grain kernels, including:

an inner member;

an outer member, the inner and outer members being relatively rotatable about an axis of rotation;

a feed chamber; and

a treatment chamber in flow communication with the feed chamber, wherein the feed chamber includes at least one guide vane which is mounted about the inner member to form a generally helical feed arrangement for operatively urging product in a feed direction, and wherein a helix angle of the at least one guide vane varies along at least part of a length of the feed chamber.

21 . A degerminator for treating grain kernels, including:

an inner member; an outer member, the inner and outer members being relatively rotatable about an axis of rotation and defining between them a treatment chamber, the outer member further defining one or more treatment chamber outlets at a discharge end thereof; and

a choking arrangement including:

A method of treating grain kernels including the steps of: relatively rotating an inner member and an outer member of a degerminator according to any one of claims 1 to 21 ; feeding grain kernels into the treatment chamber of the degerminator under pressure; and discharging product from the treatment chamber.