IL91545A - Device for the treatment of seeds - Google Patents

Abstract

Device for the treatment of seeds comprises a rotary drum mounted with its axis 18 substantially horizontal, in the bottom of the drum the bed of seeds to be treated, means for distributing the charge or the treatment agent, means for rotating the drum and directional elements fixed inside the drum for mixing the bed of seeds during the treatment, characterised in that these directional elements consist of at least one pair of vertical rows of blades of opposite inclination such that a) the rows create a vertical central passage for the flow of the seeds b) the blades are inclined with respect to the axis of rotation of the drum c) two adjacent blades belonging to each of the rows determine an angle diverging towards the peripheral wall of the drum d) the blades of one of the rows is offset angularly with respect to the other e) in the or each pair of rows 20, 21, 22 one of the rows is offset vertically with respect to the other so that seeds falling in the vertical central passage follow a sinuous path. <IMAGE> [DE3928202A1]

Description

REF : 1281/89 DEVICE FOR THE TREATMENT OF SEEDS The present invention relates to a device for the treatment of seeds .

"Seed" is understood to mean any vegetable organ which can lead to the regeneration of a plant and which is obtained either sexually, in which case reference will be made to a grain, or by vegetative multiplication, in which case reference will be made to a plant or an explant .

Treatment is understood to mean any contribution of a liquid or solid product to the surface of the seed.

If this contribution is reflected in a change in the form of the seed, for example to permit mechanical sowings of individual seeds, it involves coating techniques. The latter generally comprise, in a first stage, the deposition on the seed of an adhesive product then, possibly after partial drying, the deposition of a liquid charge or of a powder, of a treatment agent, agrochemical product, colorant, or other adjuvant, to fertilize or improve the conditions of germination of the seed.

If this contribution is made without a change in form of the seed, for example in order to give protection and possibly a coloration or an appearance, reference will be made to covering with a film. This technique comprises the deposition on the seed, by spraying, of a liquid, often aqueous, composition of a film-forming product containing a treatment agent without charge, and the simultaneous drying of the deposition obtained.

These techniques of coating and of covering with a film make use, inter alia, of rotating horizontal cylindrical turbines comprising, in addition to the actual turbine, means for placing it in rotation, means for distri-buting the charge and the treatment agent and possibly drying means . In order to ensure homogenisation of the treatment, it is known to fit, inside the turbine, mixing elements. However, despite a considerable improvement in the quality of the covering, the latter is often insuffi-cient in industrial terms when, for example, treating seeds of irregular form, of variable particle size or density, or if it is desired to perform a covering with a film requiring a high-quality deposition, that is to say with a great uniformity, over the entire surface of the seed, of the protection and/or of the coloration.

The requirement therefore exists for having available techniques and apparatuses which make it possible to carry out these treatments for a protection and an improved presentation of these seeds in order to increase the sowing yield.

The Applicant has now found that it was possible to meet this requirement using devices of the above type equipped with means for mixing and guiding which allow each seed to be presented a number of times in a substan- tially identical manner to the means for distributing the treatment agent, and for this to occur throughout the entire treatment.

The invention therefore relates to a device for the treatment of seeds comprising a rotating, substantially horizontal turbine of generally cylindrical form, in the bottom of which is the bed of seeds to be treated, comprising means for distributing the charge or the treatment agent and possibly drying means, means for rotating the turbine and directional elements fixed to the inside of the container, that is to say of the turbine, for mixing the bed of seeds during the treatment, this device being characterized in that the directional elements consist, of at least one pair of vertical rows of blades, in opposite directions, such that: a) each row is located in one of the transverse parts of the volume of the turbine, substantially parallel to the transverse walls of the latter, the two rows together creating a substantially vertical central corridor for the flow of seeds, b) the blades are inclined with respect to the axis of rotation of the turbine, c) two adjacent blades belonging respectively to one of the two rows substantially determine an angle which is open towards the top of the turbine. d) one of the rows is angularly offset with respect to the other, by pivoting with respect to the axis of the turbine, e) the useful part of the blades for mixing and guiding is distant from the cylindrical wall.

The central corridor for the flow of the seeds is an essential characteristic of the device according to the invention, this corridor being substantially vertical. Its width must be sufficient so as not to exert a shovel effect on the seeds, that is to say in order not to entrain the seeds towards the top of the cylinder and to cause them to fall back in an uncontrolled shower, without being too large, in which case the mixing or the guiding of the seeds is insufficient to ensure the homogeneity of the covering of the said seeds. Preferably, the width is from 5 to 45% of the width of the row, in particular from 10 to 40%.

In the terms of the invention, blade denotes a rigid form having a surface which makes it possible to push and above all to accompany a mass of seeds from one point to another of the volume of the turbine, that is to say to turn the seeds over effectively. This surface may be plane, or, alternatively, twisted in order to improve turning over of the seeds from the bottom towards the top and vice versa in order to avoid having to move the seeds up or to project the seeds into the turbine.

Inclination of the blades will hereinafter denote the inclination of the mean plane of the latter, that is to say the plane tangent to the surface at the centre of symmetry of this surface.

The inclination of the blades as defined above, with respect to the axis of rotation of the turbine, determines the speed of flow of the seeds in the central flow corridor.

It has been observed that highly uniform results are obtained when the width of the central corridor is approximately one third of the width of the turbine. Similarly, an inclination' of 30 to 60°, preferably of 40 to 50° , is preferred.

Moreover, the blades in the device according to the invention are such that two adjacent blades, one belonging to one row and the other belonging to the other row in the opposite direction, and which are therefore of different inclination, together form an angle turned towards the top of the turbine such that the seeds leaving the top of the bed of seeds are brought back towards the central flow corridor. This angle is generally between 30 and 60° and preferably between 40 and 50°.

Moreover, the blades in one row are not opposite those in the other row but offset angularly by pivoting with respect to the axis of the turbine. This is important to ensure both a fluidity in the flow of the seeds from top to bottom (no blockage of seeds between the lower part of the blades ) at the same time as a mixing of the seeds coming from an upper blade with those located on an opposite lower blade.

Finally, and unlike several known devices, the useful part of the blades for mixing must end at a certain distance from the adjacent transverse walls of the turbine. This distance is generally small but must be sufficient for the lateral seeds to be able to slide downwards and to fall back into the general cycle of movement towards the centre.

Therefore, the orthogonal projection of the blades on the axis of the turbine is, bearing in mind this condition and the dimensions of the central flow corridor, always less than half the width of the turbine and preferably approximately close to one third of this width.

All the above parameters may be modified as a function of the type, of the form and of the quantity of seeds to be treated, of the type of technique applied and of the effect desired for the seed. In each case, a mixing is obtained of a quality such that, on average, the seeds pass the same number of times under the projection of the treatment product.

The blades described above may be solid or hollow or perforated and made from any material provided that it is sufficiently resistant to abrasion, non-adhesive with respect to the charges provided on the seeds and inert with respect to the treatment products .

Similarly, the turbine may be solid or perforated, in particular if a suction or exterior blowing device is provided, in particular for drying the seeds.

The above description relates to a pair of rows of blades but, obviously, the device according to the invention may comprise, in order to increase the capacity and/or the throughput of the installation, several pairs of rows of blades in series, that is to say coaxial to the first row and which may be of a size and inclination which are identical to or different from the first.

According to a preferred form, the device according to the invention may be improved, principally in the case where it is intended for covering the seeds with a film, by the fact that in each pair of rows, one of the rows is offset vertically with respect to the other so that the substantially vertical central corridor gives the flow of seeds which are falling back a substantially sinuous path. This characteristic further increases the degree of homogeneity of the treatment of the seeds. In a particularly advantageous manner, one of the rows of each pair is offset vertically with respect to the other row by a distance which is approximately equal to half the common pitch of the blades in each row of the pair.

Another improvement to the device according to the invention applied to covering with a film lies in that the width of the central corridor represents 5 to 20% of the total width of the pair of rows of blades.

According to another considerable improvement of the device according to the invention in respect of all these applications, each pair of rows defines, in projection on the axis of the turbine, a zero or negative spacing of a value which is at most equal to half the width of each row. This arrangement affords the advantage that, in projection, the pairs of rows of blades overlap such that a greater density of blade per unit of volume of turbine is obtained which increases the quality of the treatment and the productivity of the device .

Moreover, still concerning productivity, it is advantageous that, against each transverse wall of the turbine, the arrangement of the rows of blades begins or ends in a half pair, that is to say a row of blades oriented towards the transverse wall in question and therefore towards the outside of the turbine in order to create a flow corridor between this row and the transverse wall in question.

The invention is explained in more detail with the aid of Figures (1) to (4) and of the description which follows, by way of illustration, of preferred examples of embodiments of the device according to the invention. These Figures represent: Figure 1: a view in axial transverse section of a device according to the invention .

Figure 2 : a view in transverse section of the device of Figure (1), along a diametral plane.

Figure 3: a view in section of a device according to the invention comprising five coaxial pairs of rows of blades.

Figure 4 : a view in section of a device according to the invention, more particularly adapted for covering with a film, comprising pairs of blades which are vertically offset.

Figures (1) and (2) show a horizontal cylindrical turbine (1) rotating about its axis (2) via drive means which are not shown, in which turbine are arranged means (3) for distributing a treatment product, for example nozzles for spraying an aqueous dispersion of a film-forming product or powder dispensers. Inside the turbine (1), in each of the parts of the volume adjacent respectively to the transverse walls (4) (5), are fixed two rows (6) and (7) of blades (6a, 6b, 6c and 7a, 7b, 7c) by means of fastenings (61, 62, 63 and 71, 72, 73), respectively, on the cylindrical wall of the turbine (1).

These blades are inclined at 45° with respect to the axis of the turbine, are distributed symmetrically with respect to the diametral plane of the turbine (cf. Figure 2), that is to say with an angle of 120° with respect to one another in this plane. Finally, the row (7) is offset by 60" with respect to the row (6). These two rows of blades create a central flow corridor (8) whose width advantageously represents one third of the width (1) of the turbine. The bed of seeds is denoted by (9) when the turbine is at rest and by (10) when it is in operation. It is clearly seen that, due to the arrangement of the blades, the seeds are mixed in a particularly homogeneous manner.

Figure (3) represents diagrammatically a turbine (11) according to the invention, comprising five pairs of rows (12, 13, 14, 15, 16) of blades (12a, 12b, 13a, 13b, 14a, 14b, 15a, 15b, 16a, 16b) of the type described in Figures (1) and (2).

Figure (4) represents diagrammatically a turbine (17) with a horizontal axis (18) comprising three pairs (20, 21, 22) of vertical rows (20a, 20b, 21a, 21b, 22a, 22b) of blades, each pair having a width 1, as well as two rows (19, 23), one at each end against the corresponding transverse wall (24, 25).

Inside each pair of blades (20, 21, 22), the two rows are offset vertically with respect to one another by. a distance equal to half the pitch of each pair and together they define a vertical central corridor of width C equal to approximately 9% of the width 1 and which permits a flow with a sinusoidal path.

The pairs (20, 21, 22), in projection on the axis (18) of the turbine (17), together have a zero spacing e, similar to the pairs (20 and 22) respectively with the end rows (19 and 23). - 11 - 91545/2

Claims (1)

1. CLAIMS 1) Device for the treatment of seeds comprising a rotating, substantially horizontal turbine of generally cylindrical form, in the bottom of which is the bed of 'seeds to be treated, comprising means for distributing the charge or the treatment agent and possibly drying means, means for rotating the turbine and directional elements fixed inside the turbine for mixing and guiding the bed of seeds during the treatment, these directional elements consisting of at least one pair of vertical rows of blades in opposite directions such that: a) each row is located in one of the transverse parts of the volume of the turbine, substantially parallel to the transverse walls of the latter, the two rows together creating a substantially vertical central corridor for the flow of seeds. b) the blades are inclined with respect to the axis of rotation of the turbine. c) two adjacent blades belonging respectively to one of the two rows substantially determine an angle which is open towards the top of the turbine. d) one of the rows is angularly offset with respect to the other, by pivoting with respect to the axis of the turbine . e) the useful part of the blades for mixing and guiding is distant from the cylindrical wall, characterized in that, in each pair of rows, one of the rows is offset vertically with respect to the other such thatTt^e^ vertical central corridor gives the are falling back a substantially sinuous path. 91545/2 - 12 - to Claim 1, characterized in tion of the blades is 30 to 60" to Claim 2, characterized in 5 that the angle of inclination of the blades is 45" · ce according to one of Claims 1 and 3, d in that the central corridor for the flow nas a width which is substantially equal to the width of the row of blades in question. ce according to one of Claims 1 to 4 , charac terized in that one of the rows is offset with respect to , the other by an angle of 60". 6) Device according to one of Claims 1 to 5, ~charac-~ terized in that one of the rows of the pair is offset 20 with respect to the other row by a distance equal to half of the common pitch of the blades in each row of the pair. 7) Device according to one of Claims 1 to 6, characterized in that the central corridor has a width equal to 25 5 to 20% of the total width of the pair of rows of blades . 8) Device according to one of Claims 1 to 7, characterized in that it comprises at least two pairs of rows defining, in projection on the axis of the turbine, a zero or negative spacing of a value which is at most equal to half the width of each row. 9). Device according to one of Claims 1 to 8, characterized in that, against each transverse wall of the turbine, the row arrangement begins with a row in which the blades are oriented towards the transverse wall of the turbine in question and which creates a flow corridor with the corresponding transverse wall. IWNSI JIN 1*>N!