FR2730712A1 - Granular product distributor esp. grain - Google Patents

Abstract

The granular distributor for grain supplied form a hopper comprises a distribution casing (22) provided with a perforated a rotating disc. Each perforation holds a granule by a vacuum applied through a first connector (26). An auxiliary tank (3) discharging into the distribution casing has a second connector (27) through which it is filled with granular products. A transmission casing (28) contains the drive for the rotating disc. The transmission casing has a third connector (29), which is connected to a source of compressed air, and is also connected to the distribution casing by a channel (30). The compressed air introduced through the transmission casing agitates the granular products entering into the distribution casing.

Description

 The present invention relates to a device for dispensing granular products in metering dispensing machines.

 The invention relates more particularly to a device for distributing grain products comprising an auxiliary distributor tank filled from a hopper or main tank containing these grain products.

 Seeders are known provided with a device for transporting granular products, in particular grains, from a main tank in at least one auxiliary tank of a distribution device by suspending the granules in a gas stream. which is guided from the main tank to the auxiliary tank by a sealed conduit.

 Document FR-1,588,490 describes a precision sowing device comprising several coulters, each of which is associated with an individual distributor comprising an auxiliary tank connected by piping to a main tank mounted on the chassis. The pipes between the main tank and each respective auxiliary tank each form an airtight elbow located higher than their ends, which plunge inside the auxiliary and main tanks. The main tank is connected by its base to a compressed air blower.

 In this known sowing device, each auxiliary tank is supplied individually and automatically with granules directly blown out of the main tank.

 The filling state of the auxiliary tank is used to regulate the quantity of granules transported.

 The document FR-2.315.834 describes a device for regulating the transport of grain products which allows the precise distribution of all types of grain whether they are "heavy" or "light", large or small. In this known device, the granules are extracted from a main tank by means of a vacuum obtained by a first air flow and the granules are presented to a second air flow to transport them to an auxiliary tank associated with a individual distributor. The two air flows are dissociated.

 The granules taken are presented to the second air flow at a point where there is either a vacuum when the auxiliary tank is in the least filling state, or a zero or positive pressure when this tank is filled or too full. When the pressure drop at the end of the duct connecting the main and auxiliary tanks reaches a certain level by accumulation of grains in the auxiliary tank of the metering distributor, the first air flow is canceled, or even reversed, thus the supply of grain to be transported is interrupted. This eliminates the risk of accumulation of granules in the transport conduit when the auxiliary tank is full, the supply of granules to transport the conduit ceasing long before the second flow becomes insufficient to ensure transport.

 The document FR-2.340.031 describes a device for the pneumatic supply of at least one auxiliary tank of an individual distributor of a seed drill from a main tank containing grain products, which comprises two intake venturis and for transporting the grains placed side by side on the same side of the main tank and supplied with air by a single conduit.

 In this known device, the grains exit from the main tank through an orifice made laterally at the bottom of the tank and directed towards the side of the latter, an inclined ascending duct directly connecting the bottom of the tank to an elevated transport pipe which communicates with the auxiliary tanks of individual distributors. Thanks to this arrangement, the risks of "stuffing" of the grains which accumulate by gravity at the bottom of the tank are reduced.

 The precision seeders used up to now also include distribution devices, also called individual distributors, which consist of a distribution casing formed so as to define, inside, a volume serving as an auxiliary reservoir for the granules or grains transferred from the main tank. The distribution casing has a first side wall into which opens a supply duct for the granules arriving at the auxiliary tank, a second side wall and a rotary distribution disc. The two side walls and the disc extend in planes approximately parallel to each other.

 The second side wall is provided with a connection fitting for a suction duct connected to a vacuum source and intended to generate a vacuum on the opposite side of the distribution disc relative to the auxiliary tank.

 The dispensing disc is provided with at least one row of calibrated holes disposed along the edge of the disc and at a distance therefrom. The holes serve to single out the granules for the suction exerted through them.

 The size of the holes is chosen according to the size, shape and nature of the granules to be distributed.

The granules can be "heavy" or "light", large or small; they can have a simple or tormented form; and they can be in their natural state or be coated for example with a treatment powder.

 To avoid a "blockage" of the granules which accumulate by gravity at the bottom of the auxiliary tank and to thus facilitate the aspiration of the granules through the holes of the distribution disc, the granules are agitated mechanically by fingers or by attached blades to the distribution disc.

 When the granules arrive in the auxiliary tank, they are sucked towards the distribution disc so that each hole of the disc is closed, or at least occupied, by a granule. Thus, each granule is kept on the disc by suction for the time of transport to an outlet of the dispensing device. Arrived in front of the outlet, the granule is detached from the disc and falls into an outlet conduit from where it falls in a furrow previously made in the ground, as the seed drill advances on the field, by a ploughshare associated with the dispensing device and closed correspondingly after introduction of the granule.

 Thus, the seed is distributed by the precision seed drill in rows of granules. The distance between two neighboring rows depends on the type of seed to be distributed; for example, it is around 20 cm for corn and around 12.5 cm for wheat.

 However, when it comes to distributing granules in tighter rows, the arrangement of the granule supply conduits and the suction conduits respectively on the first and second walls of each of the distribution devices makes it difficult, even impossible, the arrangement of the distribution devices so close to each other that one can descend below a minimum distance from the rows.

 As for the distribution discs used in the distribution devices, the number of rows of holes made in each of these discs as well as the distance between two neighboring holes depends on the quantity of granules to be distributed over a given length of a row of granules .

 However, the number of rows is generally limited to 1 or 2, since it is impossible to place stirring blades on the disc when there are more rows.

 The object of the invention is to overcome the drawbacks set out above of devices for dispensing granular products comprising an auxiliary reservoir, of a metering dispensing machine.

 The subject of the invention is a device for dispensing granular products for a metering dispensing machine, comprising a dispensing casing comprising two half-shells separated by a rotary disc provided with perforations, each of which is intended to grip and hold a granule by means a vacuum applied inside the distribution housing on a first side of the rotary distribution disc through a first connection integral with the distribution housing, an auxiliary tank provided with a second connection through which it is filled with granular products from a main tank, opening into the distribution housing on the second side of the rotary distribution disc, means for agitating the granular products and a transmission housing intended to connect the rotary distribution disc to training means.

 According to the invention, the transmission case is provided with a third connector intended to be connected to a source of compressed air and is connected to the distribution case by a channel opening into the distribution case, the compressed air introduced. through the transmission housing ensuring agitation of the granular products arriving in the distribution housing.

 Advantageously, the source of compressed air is provided with means making it possible to vary the pressure of the compressed air.

The invention also relates to the characteristics below considered in isolation or in all their technically possible combinations:
- The distribution casing comprises a first half-shell integral with the transmission casing and provided with the first connection and a second half-shell attached to the first half-hull;
- the distribution casing comprises a first half-shell integral with the transmission casing and a second half-shell attached to the first half-shell, and the first connector comprises a first essentially straight tubular element and disposed on the first half-shell and a second tubular element angled disposed on the second half-shell and opening into it;
- The channel connecting the transmission housing to the distribution housing opens into the distribution housing near the mouth of the auxiliary tank;
- The three fittings develop mainly around axes located in planes approximately parallel to a plane defined by the extent of the rotary distribution disc;
- the second half-shell of the timing cover is pivotally attached to the first half-shell;
- The timing case, the timing case and the auxiliary tank are made of a single block obtained by molding and forming at the same time the bodies of the timing case, of the timing case and of the auxiliary tank provided with first, second respectively and third fittings, completed with the other half of the timing case of the timing case and a cover of the timing case.

 The invention also relates to a precision seed drill for grain products of variable sizes comprising a main reservoir intended to receive the grain products, and at least one auxiliary reservoir associated with an individual distributor.

 In accordance with the invention, the seed drill comprises a device for distributing granular products as defined above.

 Advantageously, the source of compressed air necessary for the pneumatic supply of granular products to the auxiliary tanks is provided with at least one additional connector intended to be connected to the third connector of the transmission device for the pneumatic agitation of the granules in the tanks. auxiliaries. Thus, the granules can be agitated with air having the same pressure as the air used to transport them. This arrangement is all the more advantageous since, generally, the source of compressed air is provided with means making it possible to vary the air pressure in order to adapt it to the particular type of granules to be dispensed.

Other characteristics and advantages of the invention will emerge from the description of an exemplary embodiment made with reference to the drawing:
Figure 1 shows a seed drill fitted with a device according to the invention.

 Figure 2 shows a simplified section of a preferred embodiment of the seed drill feeder of Figure 1.

 Figure 3 shows an assembly of venturis for the device shown in Figure 2.

 Figure 4 shows a modular element of the assembly of Figure 3.

 Figures 5 and 6 show in side views from one side and the other, a preferred embodiment of the dispensing device according to the invention.

Figure 7 shows a top view of the device of the
Figure 5.

 Figures 8 and 9 show distribution discs respectively with one and two rows of perforations.

 The precision seed drill shown in Figure 1 comprises a main tank or hopper 1 intended to receive grain products of variable sizes, at least one individual distributor 2 with which is associated an auxiliary tank 3 and a device 4 for the pneumatic supply of the individual dispenser 2 from hopper 1 with grain products.

 The hopper 1 is provided with a cover 101 and an outlet 102 formed laterally below. The individual distributor 2, with which an auxiliary tank 3 is associated, is provided with a ploughshare 21. The pneumatic supply device 4 is provided with a pressure gauge 41. The hopper 1, the individual distributor 2, the pneumatic supply distributor 4 as well as a first fan 5 intended to supply compressed air and a second fan 51 intended to constitute a vacuum source are mounted on a frame 6 provided with at least one load wheel 7. The individual distributor 2 is mounted on the chassis 6 by means of two parallelograms 8 and 9 and receives the grain products through a first flexible conduit 10 subsequently called transport piping.

 A second flexible conduit 11 also connecting the individual distributor 2 to the pneumatic supply device 4 is intended for the agitation by compressed air of the grains coming from the hopper 1.

 A third flexible duct 12 connects the pneumatic supply device to the fan 5.

 The second fan 51 is connected to a distributor 14 by means of a fourth flexible duct 15. The distributor 14 is housed for example below the device 4 for the pneumatic supply of the individual distributor 2 and is connected to the latter by means of a fifth flexible conduit 16.

 The precision seed drill is also provided with a coupling 13, essentially consisting of two lower arms 131 and an upper arm 132 forming a three-point attachment, which makes it possible to attach the precision seed drill to a towing vehicle in such a way that it can be raised on the movement paths of the seed drill without sowing, on the one hand, and lowered on a field, the carrier wheel resting on the ground, during the sowing phases, on the other hand.

 The fan 5 can be fitted with one or two blades and the inlet face of its housing can be fitted with flaps.

While the flaps make it possible to regulate the air flow entering the fan, the air outlet is adjustable by an artificial leak installed near, or on, the pneumatic supply device 4.

 The operating principle of the seed drill is as follows: when the seed drill is lowered on the field, the carrying wheel 7 rests on the ground and drives, when the seed drill is towed, an individual distributor 2. Simultaneously the fan 5 provides compressed air to the pneumatic supply device 4 which extracts the grains from the hopper 1 so as to send them to the individual distributor 2 through the conduit 10.

 In embodiments comprising a second flexible conduit 11 connecting the auxiliary tank 3 of the individual distributor 2 to the pneumatic supply device 4, part of the compressed air is used to pneumatically agitate the grains arriving at the auxiliary tank 3.

In the preferred embodiment shown in the
Figure 2, the pneumatic supply device 4 is mounted adjacent to the lower part of the hopper 1 and connected to the outlet 102 thereof. It comprises a duct 31 of which at least a portion 311 is inclined upward, as well as a first venturi 32, a second venturi 33 and a wind box 34 supplying the two venturis 32 and 33. The duct 31 directly connects the bottom of the hopper 1 to the elevated transport pipe 10 which communicates with the auxiliary tanks 3.

 The first venturi 32 opens into the conduit 31 near the outlet 102 of the hopper 1, behind the latter, in the extension of said conduit. The second venturi 33 opens slightly upstream of a connection section 35 of the conduit 31 for the piping 10.

 The air flow emitted by the first venturi 32 is used to take grains descending by gravity towards the outlet 102 of the hopper 1 and to send them to the connection section 35 where they are taken up by the air flow emitted by the second venturi 33 which transports them to the auxiliary tanks 3 by the piping 10.

 The convergent of the first venturi 32 for taking the grains opens out at the upper part of the duct 31 near the outlet 102 of the hopper 1. This venturi 32 is oriented downwards to direct the air flow substantially transversely to the lateral outlet 102 which at the same time constitutes a connection section between the hopper 1 and the inclined conduit 31.

 The convergent of the second venturi 33 is oriented obliquely with respect to the duct 31 so as to direct the air flow substantially in the axis of the piping 10.

Due to their location on the same side of the hopper 1 and their substantially orthogonal orientations, the convergers of the two venturis 32 and 33 have their inputs joined. Thus, they can be supplied with compressed air by a single source of compressed air, the wind box 34. As a variant of the embodiment shown in the
Figure 2, the adjoining inputs of the two venturis 32 and 33 can be connected to the wind box 34 by a conduit.

 In operation, the pile of grains contained in the hopper 1 collapses and flows through the section of the outlet 102 thanks to the air current created by the first venturi 32 in this section. This air stream takes off the grains and routes them towards the piping 10 through the duct 31. Arrived in the connection section 35, they are entrained by the air stream emitted by the second venturi 33 and sent to the auxiliary tanks 3 through piping 10.

 Thanks to the arrangement of the inclined conduit 31 and to the lateral connection of the latter at the bottom of the hopper 1, the risks of grain jamming which would otherwise accumulate by gravity at the bottom of the hopper are reduced. Furthermore, the arrangement and orientation of the convergent of the first venturi 32 makes it possible to create a zone of high turbulence in the outlet 102 of the hopper, which causes a continuous landslide of the grains through said section as well as their detachment and their transfer. through conduit 31.

 Similarly, during periods of non-supply of the auxiliary tanks, that is to say when the auxiliary tanks 3 are full, the air jets emitted by the first venturi 32 are deflected towards the hopper 1 by the overpressure established then in the duct 31. This creates a zone of high turbulence at the bottom of the hopper 1 preventing the blocking of the grains.

 Finally, the proximity of the venturis 32 and 33 allows them to be supplied by a single wind box 34, which simplifies the construction of the supply device. The difference in resistance to the flow of the air blown by the venturis 32 and 33 to the transport piping 10 varies according to the filling rate of the auxiliary tank (s) 3, the flow d air passing through the second venturi 33 being the most important.

 Another simplification of the construction of the feed device is obtained by placing the first venturi 32 in such a way that the latter has a wall 36 in common with the bottom of the hopper 1.

To improve the fluidization of the grains at the time of their aspiration by the first venturi 32, and moreover to facilitate the initiation of the operation of the seed drill, a stick 37 is attached to the wall 36 inside and at the bottom of the hopper 1 The butt 37 is constituted by a wall whose upper part is curved and fixed on the wall 36 at the bottom of the hopper 1, and whose two side edges are attached to the corresponding side walls of the bottom of the hopper. Thus, the butt 37 forms with the wall 36 and the corresponding sections of the side walls of the bottom of the hopper, a volume whose cross section shown on the
Figure 2 has the shape of a U open at the bottom. This volume has no other opening to the air than said downward opening arranged near or at a short distance from the outlet 102 of the hopper 1.

 Alternatively, the butt can be disposed outside the hopper. In this case, the stick consists of a curved wall in its upper part which is either made by a sheet fixed to the outside face of the wall 36 of the hopper, or made in the same way as the venturis and preferably in a single block with them.

 The supply device comprises a drain hatch 38 articulated at the outlet of the inclined conduit 31 in its lower part, that is to say approximately opposite the second venturi 33. This drain hatch 38 makes it possible to ensure draining complete the hopper during cleaning and recover grains that could not have been used by the machine.

 The pneumatic supply device is also provided with two air intakes 39 and 40. The air intake 39 is disposed at the outlet, or close to it, of the wind box 34. This air intake allows the windbox 34 to be connected to the auxiliary tanks 3 of the individual distributors 2.

The air flow passing through this air intake 39 has a pressure allowing the transport of grains. It helps to fluidize them in individual distributors. This arrangement makes it possible to avoid the mechanical stirring generally used and makes it possible to obtain a stirring power which is directly a function of the main transport pressure and therefore automatically adapted to the size of the grains used.

 The second air intake 40 allows for example to mount a pressure gauge 41 on the wind box 34, and thus to continuously measure the internal pressure of the latter.

 It is also possible to equip the wind box 34 with other air intakes making it possible to use the air pressure also for additional functions which supplement or facilitate the operation of the precision seed drill.

 The pneumatic supply device 4 comprises a plurality of modular elements 50 each of which is formed so as to constitute, when assembled with another, part of the envelope of the wind box 34, a set of a first venturi 32 and a second venturi 33 and a sealed conduit 31. Together, two assembled modular elements have an air intake 39 for the connection of a flexible conduit 11 and an orifice 42 for the connection of a pipe 10.

 One of the modular elements 50 is further provided with an air intake 40 intended for mounting a pressure gauge 41. Each of the modular elements 50 is formed symmetrically and is obtained by molding, advantageously by shell molding.

 Another modular element 50 can be provided with a vent 43 allowing the regulation of the air pressure inside the wind box 34 by constituting an artificial leak.

As a variant, the vent 43 can be placed for example on the conduit 12.

 Each modular element 50 has a wall 51 intended to form, with the corresponding walls 51 of the other modular elements 50, an envelope of the wind box 34, as well as a partition 52 forming with the corresponding separation of an adjacent modular element a assembly of first and second venturis 32, 33 and advantageously but not necessarily, a sealed conduit 31. Indeed, the sealed conduits can be formed separately so as to obtain a block of sealed conduits on which is mounted the wind box 34 provided with first and second venturis 32, 33.

 The wall 51 of each of the modular elements 50 is provided at its parallel edges with openings 55, 56 and 57, 58 in the form of a semicircle, intended to form, with the corresponding openings of an adjacent modular element 50, sockets d 39 and connection orifices 42.

 The modular design of the wind box 34 makes it possible to assemble a variable number of venturis, the number corresponding to that of the individual distributors 2 with which the precision seed drill is provided.

 The wind box 34 is obtained by assembling a number of modular elements 50 which is 1 greater than that of the number of first and second venturis to be obtained. The ends of the plurality of assembled modular elements are covered by covers 61 and 62, at least one of which is provided with a connection 63 making it possible to connect the wind box 34 to the fan 5. In the embodiment shown in Figure 3, the two covers are provided with connections 63, 64. The exterior lights 57 and 58 of the modular elements on which the covers 61 and 62 are fixed, such as the orifices 42 which are not used for the connection of any pipe are closed by plates or by studs formed by joint compound to ensure the tightness of the wind box.

 Likewise, the openings 55, 56 and the air intakes 39 are closed by plates or by studs formed by joint compound when no pipe is connected. This is for example the case when the individual distributors 2 comprise mechanical agitation of the grains.

 The modular design of the pneumatic supply device and in particular the formation of each set of first and second venturis and orifices 42 intended for the connection of the grain transport piping, by assembling two identical modular elements also has the advantage of to be able to adapt more easily than until now the width of the venturis to the width of the individual distributors. This is particularly advantageous in the case where the precision seed drill must be provided with thin individual distributors allowing high-density sowing, that is to say sowing of small grains in tight rows.

 In addition, the modular design by assembling molded parts in molds without cores allows non-destructive quality control of the venturis and sealed conduits, which reduces the time and costs of control.

 The dispensing device of the invention generally comprises a plurality of individual dispensers 2 assembled adjacent to each other and is carried by at least one wheel ensuring at the same time their drive.

 The individual distributor 2 which will be described below, is shown in Figure 5 in a side view of the distribution side, in Figure 6 in a side view of the drive side and in Figure 7 in a top view.

 The individual distributor 2 comprises a distribution casing 22 for the actual distribution of the grains or granules, an auxiliary tank 3 receiving the grains from the main tank 1 and acting as a buffer tank between the latter and the distribution casing 22, and a casing of transmission 28 for driving the individual distributor 2. A distribution housing 22 comprises two demicoques 221, 222 attached to one another by a hinge 223. Inside the distribution housing 22 is mounted a rotating disc 23 or 24, respectively provided with a single row of perforations or two rows of perforations 25.

Each of the perforations 25 is intended to grip and hold a granule by means of a vacuum applied to the inside of the distribution housing 22 through a first connector 26 secured to the distribution housing 22.

 The first connector 26 consists of a first tubular element 261 essentially straight and disposed on the first half-shell 221 and a second tubular element 262 bent and disposed on the second half-shell 222. The connector 26 therefore opens out at the inside the distribution casing 22, seen in relation to the rotary disc 23 or 24, on the side of the demicoque 222 Mobile which constitutes a pivotally fixed cover on the half-shell 221.

 This arrangement allows both a flat design of the distribution casing and easy access to the connector 26 thereof for the connection of a suction duct 16.

The rotary disc can be provided with one or more rows of perforations 25. In general, variants 23 and 24 are used, respectively shown on the
Figures 8 and 9. The rotary disc 23 is provided with a single row 251 of perforations 25. The rotary disc 24 is however provided with two rows 252, 253 of perforations 25. The diameter of the perforations 25 as well as the distance between two perforations of the same row and the radial distance between two rows are chosen according to the characteristics of the granular products to be distributed.

 As an indication, the rotary discs 23 and 24 have a diameter of the order of 10 cm to 40 cm and the dimensions of the perforations vary between approximately 0.2 mm (tobacco seeds) and 1 cm (beans).

 The circumferential distance between two perforations depends on the desired distribution density, that is to say on the distance of sowing to be obtained.

 On the rotary disc 24, the radial distance between the two rows 252, 253 of perforations 25 is of the order of 1 to 2 cm.

 The auxiliary tank 3 has an essentially tubular shape, bent in its lower part, and is integral with the distribution housing 22 into which it opens out by the demicoque 221, that is to say by that of the two half-shells 221, 222 which is provided with the first tubular element 261 of the first fitting 26. The free end of the auxiliary tank 3 is provided with a second fitting 27 through which it is filled with granular products coming from the main tank 1.

 The transmission casing 28 is provided with a cover 281 allowing access to the interior of the casing and a third connector 29 intended to be connected by the conduit 11 to the source of compressed air 4. The transmission casing 28 is connected to the distribution housing 22 by a channel 30 opening into the distribution housing 22 near a mouth 225 of the auxiliary tank 3. Thus, the transmission housing 28 fulfills a double function, one being mechanical and l other tire.

 The mechanical function essentially consists in connecting the distribution disc 23 or 24 to an axis driven in rotation by the wheel or wheels 7 when the seed drill is in motion. Transmission can then be achieved by two toothed wheels connected themselves by a chain as shown in broken lines in Figure 6, or by a gear consisting only of toothed wheels.

 The pneumatic function consists in conveying compressed air to the distribution housing 22 for the pneumatic agitation of the granules in a way which at the same time makes possible a narrow design of the individual distributor 2, guarantees easy access to the fittings for connection different conduits and avoids transverse leads of the conduits.

 The first, second and third connections 26, 27 and 29 are each arranged so as to develop around axes extending in planes parallel to a plane defined by the rotating disc 23 or 24, and they do not exceed the outline of the individual dispenser as shown in Figure 7.

 The individual distributor 2 operates as follows. The granules taken from the hopper 1 are transported through the conduit 10 to the auxiliary tank 3. To avoid clogging of the granules which accumulate in quantity at the bottom of the auxiliary tank 3, compressed air is supplied from the source d compressed air 4 through the conduit 11 and the transmission casing 28 and the channel 30 for pneumatically agitating the granules. This arrangement thus facilitates the aspiration of the granules through the perforations 25 of the disc 23 so that each perforation receives a granule to transport it to an outlet of the distribution casing 22, from which the granule falls to the ground.

 The reference signs inserted after the technical characteristics mentioned in the claims, have the sole purpose of facilitating the understanding of the latter, and in no way limit their scope.

Claims (9)

 1. A device for distributing granular products for a metering dispensing machine, comprising a distribution casing (22) comprising two half-shells (221, 222) separated by a rotary disc (23, 24) provided with perforations (25) each of which is intended to grip and hold a granule by means of a vacuum applied inside the distribution casing (22) on a first side of the rotary distribution disc (23, 24) through a first connector ( 26) integral with the distribution casing (22), an auxiliary tank (3) provided with a second connector (27) through which it is filled with granular products from a main tank (1), and opening into the distribution housing (22) on the second side of the rotary distribution disc (23, 24), means for agitating the granular products and a transmission housing (28) intended to connect the rotary distribution disc (23, 24) to drive means, characterized in c e that the transmission case (28) is provided with a third fitting (29) intended to be connected to the distribution case (22) by a channel (30) opening into the distribution case (22), the compressed air introduced through the transmission casing (28) ensuring agitation of the granular products arriving in the distribution casing (22).  2. Distribution device according to claim 1, characterized in that the distribution housing (22) comprises a first half-shell (221) integral with the transmission housing (28) and provided with the first connector (26) and a second half -hull (222) movable attached to the first half-hull (221).  3. Distribution device according to claim 1, characterized in that the distribution housing (22) comprises a first half-shell (221) integral with the transmission housing (28) and a second half-shell (222) attached movably to the first half-shell (221) and in that the first connector (26) comprises a first essentially straight tubular element (261) and disposed on the first demicoque (221), and a second bent tubular element (262) disposed on second half-shell (222) and opening into it.  4. Dispensing device according to one of claims 1 to 3, characterized in that the channel (30) connecting the transmission housing (28) to the distribution housing (22) opens into the nearby distribution housing (22) a mouth (225) of the auxiliary tank (3).  5. Dispensing device according to one of claims 1 to 4, characterized in that the first, second and third fittings (26, 27, 29) develop mainly around axes located in planes approximately parallel to a defined plane by the extent of the rotary distribution disc (23, 24).  6. Distribution device according to one of claims 1 to 5, characterized in that the second half-hull (222) of the distribution housing (22) is pivotally attached (23) to the first half-shell (221).  7. Distribution device according to one of claims 1 to 6, characterized in that one (221) of the demicoques of the distribution casing (22), the transmission casing (28) and the auxiliary tank (3) are formed in a single block obtained by molding and forming at the same time the bodies of the distribution casing, of the transmission casing and of the auxiliary tank provided respectively with the first, second and third connections (26, 27, 29) supplemented with the other ( 222) of the half-shells of the timing case (22) and of a cover (281) of the transmission case (28).  8. Precision seed drill for grain products of variable sizes, comprising a main tank (1) intended to receive the grain products, and at least one auxiliary tank (3) associated with an individual distributor (2), characterized in that 'It comprises a device for distributing granular products according to any one of Claims 1 to 7.  9. Seeder according to claim 8, characterized in that the compressed air source (4) necessary for the pneumatic supply of the auxiliary tanks (3) is provided with at least one connector (39) intended to be connected to the third connection (29) of the transmission device (28) for pneumatic agitation of the granules in the auxiliary tanks (3).