Degerminator, in particular for degerming cereals
Technical field
The present invention concerns a degerminator, in particular for degerming cereals, according to the preamble of main claim No. 1. Technological background
Machines having the above-mentioned characteristics are widely used in the technical field of degerming of cereals for separating the germ and the cereal part closest to the germ from the cereal grain. Since the major quantity of fats is in fact concentrated principally in the germ, such separation makes it possible to reduce drastically the amount of fats present in the cereal. For example, in the specific field of degerming of maize, the content of fats in the germ is of the order of 4%-5% by weight and is reduced even to less than 1% as a result of splitting and separation of the germ from the remainder of the grain. The reduction of the content of fats improves the quality of the flours or grist which can be obtained in the subsequent milling operations. In this technical field, degerminators are known which are provided with a rotor with one or more beater members protruding from the outer surface of the rotor and capable of impacting the material to be degermed. This material is fed into an area defined annularly between the rotor and an outer scouring jacket which receives the rotor itself. The splitting of the cereal is effected by friction caused principally by the centrifugal action imposed by the rotatory motion of the beater members between grains and between grain and scouring jacket. The product to be degermed is loaded at one axial end of the rotor and is discharged at the opposite end, while the rejected material, consisting of the cereal germs and fatty flour dust (that in contact with the germ), is discharged via through-apertures provided in the scouring jacket and is eliminated for example via a collecting hopper.
In known machines of the aforesaid type, the rotor and the beater members are conventionally obtained, according to a first type, in one piece with one another and in a single casting. As an alternative, according to a second known type,, the rotor may be obtained by fabrication, starting from two half-rotors subsequently welded and on which the beater members are in
turn secured by welding. The two half-rotors are further typically welded with a slight mutual axial offset so as to produce a slightly eccentric rotational movement which makes it easier to obtain a tangential path of the cereal in the impact with the beater member. One of the limits encountered in these known types of degerminators lies in the fact that the consumption of the beater members due to wear necessarily requires the replacement of the entire rotor, or at least the complete dismantling of the rotor for the restoration of the beater members, which operation, apart from being rather complex, necessitates the shutdown of the machine, with a consequent reduction in productivity and an increase in maintenance costs.
Another limit is linked to the fact that, whenever different splitting characteristics are required (for example in the splitting of cereals of different kinds), such as to involve different geometry and/or dimensions of the beater members, it is necessary to replace the rotor with another having the preselected configuration, with a consequent increase in the times and costs involved.
Yet another limit lies in the relative complexity of construction and machining of the rotors currently used. Description of the invention
The problem underlying the present invention is that of providing a degerminator, in particular for degerming cereals, structurally and functionally designed so as to make it possible to overcome the limits mentioned with reference to the prior art cited. This problem is solved by the invention by means of a degerminator produced in accordance with the claims which follow. Brief description of the drawings
Further characteristics and advantages of the invention will become clearer from the following detailed description of one of its preferred exemplary embodiments illustrated, by way of non-limiting example, with reference to the appended drawings, in which:
Figure 1 is a perspective view of a degerminator according to the present invention,
Figure 2 is a partial perspective view of a detail of the machine of Figure 1, - Figure 3 is a partial view in axial section of the rotor unit of the machine of the preceding figures,
Figure 4 is a view in side elevation of a detail of the machine according to the invention,
Figure 5 is a view in section along the line V-V in Figure 4, - Figure 6 is a perspective view of the detail of Figure 4,
Figure 7 is a perspective view of a further detail of the machine according to the invention. Preferred way of carrying out the invention
With reference to the drawings mentioned, the reference 1 indicates as a whole a degerminator, particularly but not exclusively designed for degerming cereals, and produced according to the present invention.
The machine 1 comprises an axially symmetrical rotor 2, rotatably supported about an axis of rotation X and coaxially connected to a transmission shaft 3. The rotor is driven in rotation via a belt transmission, looped between a first pulley 4, keyed on the shaft 3, and a second, motorized pulley (not shown) driven by an electric motor 5. It is to be understood that other transmissions may be provided for the rotational drive of the rotor 2, the one described representing a preferred choice.
The rotor 2 is rotatable within a scouring jacket 6, of conventional configuration p_er se, conveniently produced as two half-jackets 6a, 6b. The jacket 6 is in turn enclosed in a box-like casing 7 with one or more casing portions 7a pivotable to open for access to the rotor 2.
Between the rotor 1 and the inner surface of the scouring jacket 6 a substantially annular chamber 8 is defined into which the product to be degermed is introduced axially. In particular, the product is introduced into the chamber at one axial end of the rotor 2, by means of a worm conveyor 9, in its turn fed by gravity from a feed aperture 10.
The degermed product is discharged at the opposite axial end of the rotor 2, via a discharge aperture 11, while the rejected material, consisting of the product germs and of fattier flour dust (that in contact with the germ) is discharged via a plurality of through-apertures (not shown) provided in the thickness of the scouring jacket 6, being configured and arranged conventionally p_er se.
To split the product fed into the chamber 8, the rotor 2 is provided with two or more beater members, both indicated by 12, which extend longitudinally in the direction of the axis X and have a radial projection beyond the cylindrical outer profile of the rotor 2. Although two beater members are provided in the example described, it is to be understood that any required number of such members may be provided, depending on the requirements for preparation of the product to the degermed.
According to a principal characteristic of the invention, each beater member 12 is structurally independent of the rotor 2 and is removably secured to the rotor itself, as will appear clearly in the continuation of the description.
Each beater member 12 comprises a base 13 for attachment to the rotor, which base is provided with a plurality of axially aligned through-holes
14 which are capable of superposition with corresponding threaded holes 15 provided in the thickness of the rotor 2 for screw fixing of the beater member
12 on the rotor. At the seat of the attachment base 13 a flattening of the rotor 2 may also be provided to increase the contact surface of the base 13 on the cylindrical jacket of the rotor. e
From the base 13 of the beater member 12 a portion 16 is raised on which is defined a beating surface 17 capable of impacting the material in the splitting phase within the chamber 8. Said surface 17 extends from the base
13 in the direction of a free edge 16a of the portion 16.
The base 13 of the beater member is also provided with a chamfer 13a formed along the side of the base opposed to the portion 16. The chamfered shape of the profile of the base 13 makes it possible to deflect the material being split which impacts the beater member 12 in the direction of the free
edge of the beating surface 17 in order to facilitate splitting of the product to be degermed.
According to a further characteristic of the invention, the projection of the beater member 12 from the cylindrical profile of the rotor 2 is adjustable in a radial direction via spacer means comprising one or more plate-like members
18, of preselected thickness, capable of being inserted between the rotor and the beater member at the attachment base 13.
Said spacer members 18, made for example from sheet metal, have through-holes 18a corresponding in number and position to those of the attachment base 13 in order to be rigidly fixed to the beater member 12 by means of the same screw means for locking same on the rotor. It should be noted that to adjust the radial projection of the beater member 12 it is possible to provide one or more of the spacer members 18 having a preselected thickness in order to obtain a shimming equal to the desired adjustment.
In order to guide the product being split along an optimum tangential path in the direction of the beater member 12, the rotor 2 may further be provided with deflector means, indicated as a whole by 20, capable of deflecting the product to be split. More particularly, said deflector means comprise at least one raised portion 21 (two in the example described) extending axially in the direction of the axis X and protruding radially from the . rotor 2 and also spaced circumferentially from the beater member 12. Said raised portion 21 is prolonged in a plate-like portion 22 removably secured to the rotor 2 by screw means engaged in a plurality of through-holes provided in the portion 22 and capable of superposition with corresponding threaded holes provided axially in the outer surface of the rotor.
Said plate-like portion 22 is conveniently received, at least partially, in a seat 23 provided in the rotor. The raised portion 21 together with the chamfer 13a of the base 13 serves gradually to deflect the product to be split and to divert the path thereof radially away from the rotor in the direction of the free edge of the beating surface 17 for greater efficiency of splitting of the product.
Figure 5 indicates diagrammatically, by dashed lines, the theoretical tangential trajectory induced by the deflection produced by the effect of the raised portion 21 and of the chamfer 13a.
The invention thus solves the problem posed while providing numerous advantages with respect to the known solutions.
A first advantage lies in the fact that, owing to the provision of beater members removably secured to the rotor according to the invention, the replacement of such members, because of wear, is particularly rapid and such as not to require either the dismantling or the replacement of the rotor. A second advantage is that the removable beater members according to the invention permit the interchange of same with others of different dimensions and geometry if required, depending on the requirements for preparation of the product.
A further advantage lies in the fact that, in the machines according to the invention, owing to the adjustability of the projection of the beater member with respect to the rotor, it is possible to improve the splitting efficiency and consequently the productivity, even in the presence of products of different kinds to be degermed which require different dimensions and geometry of the beater members. Moreover, owing to the increased splitting efficiency obtainable; the machines according to the invention make it possible to reduce drastically the percentage of fats present in the degermed product.
Yet another advantage lies in the constructional simplification of the rotor, which, differing from the known solutions, has an axially symmetrical (not eccentric) configuration and is obtained by simple mechanical machining operations, while at the same time guaranteeing, if not imprpving, the performances obtained with rotors of conventional configuration.