IE20000116A1 - Slurry Spreader - Google Patents

Abstract

A slurry spreader having a roller (1;10;79) which has an array of projecting nozzles (5) for penetrating the soil and injecting slurry into the soil, a slurry distribution mechanism which operates automatically as the roller (1;10;79) undergoes its rolling motion so as to distribute slurry to nozzles (5) which are oriented downwardly; and a mechanism for applying a vaccum from a vaccum source to the nozzles for sucking slurry back from the nozzles (5). The mechanism for applying a vacuum is adjustable so as to apply vacuum to one or more nozzles (5) at a time. The slurry distribution mechanism comprises a stator (17) having an aperture (18;215) connected to a slurry supply and a rotor (14) having a plurality of apertures (15;201) connected to the nozzles (5) each aperture (15;201) in the rotor (14) being brought into register with the aperture (18;215) in the stator (17) during rolling motion of the roller (1;10;79). The mechanism for applying a vacuum may also be a stator (17) and a rotor (14). <Figure 2>

Description

The present invention relates to slurry spreaders.

Prior Art One known arrangement for spreading slurry involves the use of a slurry spreader fitted to the back of a wheeled slurry tank pulled along behind an agricultural tractor.

Another known arrangement involves the use of a slurry spreader connected to and pulled along behind a first agricultural tractor while a separate wheeled slurry tank is connected to and pulled along behind a second agricultural tractor. In use, the two tractors are driven side by side. A hose connects the slurry tank to the slurry spreader so that the latter is continuously supplied with slurry.

A third known arrangement is where slurry is supplied continuously to a slurry spreader from a farm yard, through a long supply hose, which may be wound on a coil, • which allows movement of the spreader in a field etc.

Irish Patent No. 52241 (Twose) describes a slurry spreader for use in connection with the two-tractor arrangement described above. The slurry spreader consists of a disc . cutter which moves along the ground forming a linear incision or cutting in the ground, a ploughshare located just behind the disc cutter for further opening the incision to form a furrow, and a nozzle immediately behind the ploughshare for injecting slurry into the furrow before the latter closes over. Many similar systems are known.

One disadvantage of the slurry spreader described in the above Irish patent is that it causes some damage to the soil on which the slurry is being spread in particular IE 000116 uprooting and damaging grass. This slurry spreader may also pull up sub-surface stones. It is not desirable to create furrows in a field that is used as pasture and/or for fodder crops such as hay or silage. Placing slurry beneath the ground surface is desirable however as it reduces odour and prevents ground surface run-off. It also does '· not spoil pasture.

US patent No. 5,178,078 (Prendergrass) discloses a process and apparatus for improving the friability of soil. Compressed air is blasted through nozzles which penetrate the soil. The nozzles are mounted on a hollow drum mounted upon a frame work in a manner to rotate about a horizontal axis. The cylindrical wall of the drum holds a multitude of nozzles arranged in rows, each nozzle having a plurality of upwardly directed apertures. When a row of nozzles are in a vertically downward position penetrating the soil, a short duration pulse of air is passed through the nozzles. The device is not suitable for the delivery of slurry. Most slurries in particular those such as cattle/pig effluent taken from slatted sheds is quite viscous and contains a high proportion of solids and fibres. Such a slurry would tend to cause the device to clog up and become inoperable even after a very short period of use.

US patent No. 4,677,921 (Brown) relates to a rolling point agricultural spiked wheel injector system for injecting a fluid as a liquid chemical or gas into the ground. However it is apparent that the device described is suitable for use only along vegetable rows etc. and can supply only a very limited quantity of fluid. It is not suitable for the delivery of a slurry to the soil, particularly not on the scale required for economic disposal of large quantities of slurry.

SU 1,824,058 (Central Black Soil etc.) relates to a unit for liquid fertiliser introduction into the soil which has a metering device made as a cassette and drum fitted on a hollow axle and provided with radial baffles. The drum is positioned a relatively large distance above the ground. Needles are used to inject the liquid fertiliser into the ground. The needles are quite long and are easily damaged making it unsuitable for IE 000116 spreading slurry. The needles would also be subject to blockage by solids/fibres in slurry. The drum does not contact the ground and does not therefore function as a roller.

None of these devices provide a mechanism to prevent spillage of liquid from the injection system which is retained by the nozzles/needles after injection is complete.

In conventional slurry spreaders a valve is provided on the slurry pump, in one position of the valve a vacuum is generated to allow slurry to be sucked into the tank of the slurry spreader. In a second position of the valve the interior of the slurry spreader tank is pressurised by air pumped into the tank forcing the slurry from the spreader.

Object and Summary of the Invention An object of the present invention is to provide an improved slurry spreader 15 which may be used in any of the above described arrangements.

. The present invention provides a slurry spreader comprising : a roller which rolls along the ground and which has an array of projecting nozzles for penetrating the soil and injecting slurry into the soil; a slurry distribution mechanism which operates automatically as the roller undergoes its rolling motion so as to distribute slurry to nozzles which are oriented downwardly; and a mechanism for applying a vacuum from a vacuum source to the nozzle for sucking slurry back from the nozzles.

One advantage of the slurry spreader of the invention is that slurry is injected beneath the ground surface without substantial damage to the soil. Furthermore wastage of slurry from the nozzles which are not in contact with the ground is substantially reduced.

Preferably slurry is distributed only to nozzles which are oriented downwardly particularly nozzles which are at, or about, the lowermost position (fully penetrated IE 000116 position ) during rolling motion of the roller, the supply of slurry being effected when the nozzle is close to, but not at, its lowermost position. It is desirable to supply slurry only to nozzles which have passed the lowermost position and are partially retracted from the soil.

In a preferred embodiment the distribution mechanism and the mechanism for applying the vacuum are operable in a continuous cycle. A continuous supply of pressurised slurry can be effected, and a continuous vacuum can be also maintained. Suitably the vacuum mechanism and the distribution mechanism are operable simultaneously and more preferably the mechanism for applying a vacuum exposes a nozzle to a vacuum immediately after the distribution mechanism has supplied slurry to the nozzle and it has been injected into the soil (ground). This helps to keep the nozzles unblocked and/or free of slurry thus eliminating blockage problems and spillage/dribbling of slurry from nozzles, and indeed aids keeping the entire injection system free of clogging etc.

In a more preferred arrangement the distribution mechanism supplies slurry to one nozzle at a time.

In an alternative arrangement the mechanism for applying a vacuum is adjustable so as to apply vacuum to one or more nozzles at a time, while suitably the mechanism for applying a vacuum applies a vacuum to one nozzle at a time.

In a preferred embodiment the nozzles are arranged so that each nozzle is a -25 circumferential distance apart from the others about the roller.

In a more preferred embodiment the nozzles are arranged in a helical or parthelical pattern, or a series of helical or part-helical patterns. This arrangement is particularly favoured as it allows the nozzles to be fed slurry one by one in accordance with rotational motion of the roller.

IE 000116 In a more preferred embodiment the slurry distribution mechanism comprises a stator having an aperture connected to a slurry supply and a rotor having a plurality of apertures, connected to the nozzles, each aperture in the rotor being brought into register with the aperture in the stator during rolling motion of the roller. This arrangement advantageously allows slurry to be continuously supplied to the stator/rotor mechanism and to be continuously distributed to the nozzles while the nozzles undergo rotation with the roller. It also allows a continuous pressure of slurry to be maintained. It is not necessary to apply/remove the pressure on the slurry repetitively.

In one embodiment the rotor is part-cylindrical in shape and has an internal annular groove about an internal circumference, the apertures in the rotor passing from the internal surface of the groove to the exterior of the rotor, the stator being engageable in the groove, the slurry and vacuum apertures in the stator being arranged to come into register one by one with the apertures in the rotor, on rotation of the rotor.

Preferably the mechanism for applying a vacuum comprises a stator having an aperture connected to the vacuum source and a rotor having a plurality of apertures connected to the nozzles, each aperture in the rotor being brought into register with the aperture in the stator during rolling motion of the roller. In a preferred embodiment the apertures in the rotor are elongate. More suitably the slurry distribution mechanism and the mechanism for applying a vacuum comprise the same stator having an aperture connected to a slurry supply and an aperture connected to the vacuum source, and the same rotor having a plurality of apertures, each aperture in the rotor being brought in turn into register with the aperture in the stator connected to the slurry supply and then the aperture in the stator connected to the vacuum source, during rolling motion of the roller. This allows both the vacuum and slurry to be applied to the nozzles by the same mechanism simplifying the internal construction of the device.

In a preferred embodiment a seal is provided between the stator and rotor to prevent leakage of slurry and/or vacuum at the interface between the stator and the rotor. In a preferred construction the seal is provided by a gasket which is suitably constructed of a IE 000116 plastics material such as nylon. In a more preferred construction the gasket is formed by a collar recessed in a groove located in the rotor or the stator. The collar mates with the groove and with a corresponding annular recess in the rotor/stator forming a reliable seal. The collar has apertures corresponding to those of either the stator or the rotor so that the transfer of slurry and/or vacuum between the stator and the rotor is not compromised. In a preferred arrangement the collar is located in a groove on the rotor and mates with an annular recess on the stator to form a reliable seal.

The slurry spreader may comprise a bank of rollers preferably arranged side by side.

The provision of a bank of separate small rollers instead of one large roller is intended to mitigate the problem of clogging which might arise in a larger roller with long internal slurry flow-paths.

The slurry spreader is preferably fitted to a slurry tanker. Suitably the tanker and/or the spreader is provided with a pump for supplying slurry to the spreader and a vacuum pump which provides a vacuum source.

Brief Description of the Drawings • The invention will now be described more particularly with reference to the accompanying drawings which show, by way of example only, various embodiments of a slurry spreader according to the invention. In the drawings: Figure 1 is a perspective view of a first embodiment of a slurry spreader, comprising one large roller; Figure 2 is a diagrammatic front elevation of a slurry spreader of the invention; Figure 3 is a perspective view of the stator shown in Figure 2; IE 000116 Figure 4 is a perspective view of the rotor shown in Figure 2; Figure 5 is a perspective view of a second embodiment of a slurry spreader, comprising a bank of smaller rollers; Figure 6a is a perspective view from the left hand side, of a slurry tanker with a slurry spreader of the invention fitted thereto; Figure 6b is a perspective view from the right hand side, of a slurry tanker with a slurry spreader of the invention fitted thereto; Figure 6c is a rear view of the slurry tanker and slurry spreader shown in Figures 6a and 6b; Figures 7a and 7b show two alternative nozzles; and Figure 8 is a perspective view of an alternative rotor; Figure 9 is a perspective view of an alternative stator; Figure 10 is a perspective view of the rotor of Figure 8 and the stator of Figure 9 assembled together; and Figure 11 is an exploded view of a sealing arrangement between a feed line and the rotor.

Detailed Description of the Preferred Embodiments Referring initially to Figure 1, a slurry spreader comprises a hollow cylinder or roller 1, draw arms 2 for pulling the cylinder or roller along behind a slurry tanker IE 000116 (which in turn may be towed behind a tractor) or directly behind a tractor in the direction indicated by arrow A so that the cylinder or roller rolls along the ground about its horizontal axis as indicated by arrow B, an eccentric inlet 3 having a hose 4 connected thereto for feeding a supply of slurry from the slurry tanker to the cylinder as indicated by arrow C, and an outlet in the form of an array of projecting nozzles 5 (only some of which are shown), with slurry being pumped outwardly through the downwardly facing nozzles as indicated by arrow D, and thus injected into the ground. The roller 1 also comprises a vacuum line 60, the function of which is described in more detail below. The slurry spreader of the invention not only spreads slurry but also aerates the ground. The slurry spreader of the invention could be a self-propelled slurry tanker instead of being towed behind a tractor. The slurry spreader of the invention may also be supplied with slurry from a tanker drawn by a second tractor (as described below) or indeed slurry may be pumped directly to it from a slurry holding tank in a farmyard etc.. It has been found that supplying slurry to a nozzle which has penetrated the ground but has not yet reached its lowermost position on a given revolution of the roller allows for better injection of slurry into the ground, than is the case for injection at the lowermost (deepest penetration) position. It has been noted that injection of the slurry into the ground by nozzles which have just passed their lowermost position and have withdrawn to a partially penetrated position in the soil gives very satisfactory injection. It is thus desirable to arrange the injection system so that injection takes place with penetration of the nozzle to a depth less than full penetration and preferably after the nozzle has passed its fully penetrated position.

Referring now to Figures 2 to 4 the internal construction of a roller 1 of having slurry supply hose 19 connected to an eccentric inlet 31 will be described. The vacuum line 60 is also eccentrically located on the roller 1. The slurry distribution arrangement comprises a rotor 14 (shown in more detail in Figure 4) including a series of apertures 15 respectively corresponding to each nozzle 5, and a stator 17 having a slurry inlet aperture 18 at the lower end thereof. In operation, slurry enters the roller from the hose 19 and into the inlet nozzle 31, and then flows along a further hose or pipe 21 to the aperture 18 in the stator 17 (following the path indicated by the arrows and the dotted IE 000116 line). From there it passes through an aperture 15 in the rotor 14 (which is in register with the aperture 18) into a further pipe 22 to a downwardly orientated nozzle 5 which injects the slurry into the ground. For the sake of clarity only the flow path to one nozzle 5 is shown.

The axle 90 of the roller 1 is stationary when the cylinder 10 is rolling. The stator 17 remains stationary also. A bearing housing 20 houses a bearing about which the rotor 14 is free to rotate, so that the rotor 14 moves independently of the axle 90. As the cylinder 10 undergoes its rolling motion, the rotor 14 which is fixed within the roller 1 undergoes a corresponding rolling motion turning about the axle 90. During the rolling motion of the roller 10, each aperture 15 in the rotor 14 is brought in turn into register with the aperture 18 in the stator 17 (the aperture 18 and the aperture 15 being of approximately the same dimensions). When the apertures 15,18 are in register, slurry flows through the two apertures and into a pipe 22 and then on to a nozzle which ( has just passed its lowermost position on a given revolution of the roller. In the embodiment shown only one nozzle 5 is supplied with slurry at any given time. As a result, slurry is. continuously pumped out through the correctly positioned nozzle 5, but no slurry is pumped out through the other nozzles. A bushing 26 is provided on each side of the roller to retain the axle 90 in its correct position on the roller 1. The bushing 26 also accommodates the slurry inlet 31 and the vacuum line 60, allowing them to remain stationary while the roller 1 rotates. The pipes 22 are unbranched and run each from an aperture 15 in to a single nozzle 5 so that each nozzle 5 has an individual supply of slurry. This arrangement allows the full pressure of the pumped slurry to be applied to each nozzle.

Figures 2 to 4 also show the internal features of the vacuum mechanism of the roller 1 of Figure 1. A vacuum is applied upstream of the nozzles 5 which have just moved out of the ground so as to suck slurry back from the nozzles into a slurry tank (where slurry is supplied from a tank) for subsequent use. Alternatively a trap may be provided to catch slurry removed under vacuum. The source of the vacuum may be a vacuum pump of conventional type which pumps slurry from a slurry tanker to the IE 000116 ίο slurry spreader or may be a separate vacuum pump provided on the spreader. As seen in Figure 2 a vacuum hose 60 leads from a vacuum pump into the roller to the stator 17 which is provided with two vacuum apertures 61 which are located a small arc anticlockwise (as shown in Figure 3) of the slurry aperture 18. As the rotor 14 •5 undergoes its rolling motion, each aperture 15 in the rotor 14 is brought in turn into register with the slurry aperture 18 in the stator 17 in order to pump out slurry into the ground (as described above) and immediately thereafter is brought into register with the vacuum apertures 61 to suck back any slurry which has not been pumped out. Dual apertures 61 have been found to be useful in ensuring that the nozzles 5 are sucked clean of slurry. In particular, the provision of the vacuum suck-back protects the rotor and stator from the build-up of fibres and other debris found in the slurry. In place of dual apertures a single vacuum aperture may be elongated in an arc shape so as to allow vacuum to be applied to more than one nozzle at a time and optionally may be adjusted by means of a slide arrangement which can be moved so that vacuum is applied to a predetermined number of nozzles 5. This is particularly useful where the slurry has a low viscosity/high liquid content. One of the main advantages of the vacuum system is that there is no shut-off mechanism for blocking slurry not injected which can get fouled or clogged by the slurry or fibres in the slurry. For instance if valves are used to close the apertures in the nozzles 5, the valves are likely to become clogged with debris and their performance is adversely affected. Furthermore the removal of slurry retained in the nozzles 5 will help to keep the nozzles 5 clear, and if they should become blocked to help to unblock them. The vacuum is applied individually in turn to each nozzle 5, so that a nozzle 5 receives firstly the full pressure of slurry and then secondly the full vacuum force. The vacuum may be provided from a separate pump (as described below) to the pump supplying the pressurised slurry, though it is also possible to use one pump which can perform both tasks simultaneously. A positive displacement pump is particularly useful. The positive displacement pump throughputs slurry having a direct slurry intake and a slurry output thus pumping the slurry directly rather than the conventional method of pressurising the interior of the slurry tanker to spread the slurry.

IE 000116 π Figure 4 shows a perspective view of the rotor 14, containing a number of 1' apertures 15. The slurry flow to the nozzles 5 is a function of the diameter of the apertures 15 and the time during which each aperture 15 is in full or partial register with the aperture 18. Similar criteria apply to the vacuum applied to the nozzles 5 through apertures 61.

A sealing arrangement between the rotor 14 and the stator 17 is provide by a gasket in the form of a ring or collar 91. The collar 91 is constructed of a nylon material and the apertures 15 extend through it also. The rotor 14 comprises a disc or plate 92 into which is channelled an annular groove or recess 93. The collar 91 is an exact fit within the groove 93 and seals to the disc 92. The disc 92 has a centrally located bearing 94 in a bearing housing 95 fastened to the disc by bolts 96. The rotor is mounted within the roller 1 for rotation about the bearing 94 as described previously. (The bearing housing 94 corresponds to the housing 20 of Figure 2). Holes 97 in the disc 92 allow for ease of handling of the rotor 14.

The stator 17 comprises a disc 100 which has an annular channel or groove 101 located about its periphery. The annular wails of the channel 101 are provided by a peripheral rim 102 machined into the disc 100 and a smaller concentric ring 103 fixed to the disc by fasteners 104. The stator 17 is fixed to the axle 90 by a plate 105 and fasteners 106. The collar 91 of the rotor 14 and the channel 101 of the stator 17 mate to form a slurry/vacuum seal between the stator and the rotor when the slurry spreader is assembled. Extending the vacuum apertures across the entire width of the channel 101 has been found to be very useful as this decreases the likelihood of debris etc. remaining after the vacuum has been applied. Making the slurry supply apertures of the rotor elongate may also be used to increase slurry throughput.

As shown in Figure 5, the slurry spreader may alternatively consist of a bank of smaller rollers 10. The rollers 10 are mounted side by side and are connected by draw bars 11 to a yoke 12 which may be pulled behind an agricultural tractor or attached to a slurry tanker. Any pattern of arrangement of these rollers is possible - e.g. one directly IE 000116 behind the other, offset in any direction from each other or side by side as shown. Each roller has its own inlet 13. The principal advantage of the arrangement shown in Figure 5 over a single roller arrangement is that the path which the slurry must travel within a roller from the roller inlet 13 to the nozzles 5 is relatively short and relatively similar for each different nozzle, and as a result there is more likely to be a consistent application of slurry to the soil. In contrast, in a single roller arrangement the nozzles 5 which are remote from the inlet 3 may experience a lower slurry pressure, and may therefore become more easily clogged, and in general the quantity of slurry applied to the soil may not be constant along the axial length of the roller 1, but instead may be greater at the inlet end and less at the other end. As can be seen from Figure 5 the nozzles may be arranged in pairs. Pairing up the nozzles is one method of increasing the output of the spreader. The system which remains most fibre/debris free is the system where vacuum is applied nozzle by nozzle.

Figures 6a to 6c show a slurry spreader of the invention attached to the rear of a slurry tanker 72. The tanker 72 is a conventional tanker in most respects. It has a cylindrical tank body 73 on a tow-bar/chassis arrangement 74. It has wheels 75 protected by mudguards 76. The tanker has two pumps. The first is a positive displacement pump 77 which pumps slurry directly from the tank body 73 through two feed pipes 120, 121 which in turn supply the rollers 79 with slurry. The pump 77 sucks slurry from the rear of the tank body 73 through a pipe 78 and passes the slurry from the bank body through the body of the pump 77 and into the two slurry feed pipes 120,121. Each roller 79 comprises the distribution system described above, and roller 79 has a plurality of nozzles 5. As also can be seen from Figure 6a to 6c the nozzles 5 are arranged in a part-helical manner (staggered) about the rollers 79. This arrangement, together with the fact that each nozzle 5 is supplied with slurry from an individual feed line ensures that (for each roller) only one nozzle receives pressurised slurry at a time. Each of the rollers 79 is pivotally connected to the tanker 72 by a mounting frame 80, so as to allow movement of the rollers 79 over uneven ground. This may be achieved using a coil spring arrangement. A single hydraulic ram (or dual hydraulic rams, one on each side of the tanker 72) is provided to raise and lower the rollers 79 (simultaneously IE 000116 or individually). A vacuum pump 81 is also provided on the tanker 72. The vacuum pump 81 sits on top the displacement pump 77. The pumps 77 and 81 are each driven from the power-take-off shaft of a tractor by a single shaft 82 to which the power-takeoff shaft is connected. The shaft 82 directly drives the displacement pump 77 while a chain 83 fitted between the shaft 82 and the vacuum pump 81 drives the vacuum pump simultaneously. For separate operation of the vacuum pump and the displacement pump both may be operated hydraulically by individual supplies. The vacuum pump 81 generates a vacuum in a pipe 84 which leads to a secondary trap 85, which in turn is connected to a pipe 86 which runs to a primary trap 87. The primary trap 87 and the secondary trap 85 each have an internal baffle which is designed to remove any slurry in the vacuum and return it to the tank body 73. Typical mechanisms to prevent slurry entering the vacuum line including ball shaped floats which rise with the level of the slurry may be used in the slurry spreader of the present invention. Typically the float cuts off the vacuum line at a position within the traps 85,87. A single pipe 88 exits the rear side of the trap 87 and runs to the rear of the tank where it branches into a T-branch 89. The vacuum is applied from the T-branch 89 to each roller 79 by individual pipes 110 and 111. A valve 113 which can be operated hydraulically is used to close off the vacuum to the rollers. Slurry can be taken into the tank 73 through slurry intake valve 112.

The rollers 79 are shown in the raised position in Figures 6a and 6b. They are lowered in the working position in Figure 6c. As shown in Figure 6c a series of scrapers 114 are arranged on the mounting frame 80 to scrape about the rollers, following a circumferential track between the nozzles 5 to keep the rollers free of caked mud etc.

.« The vacuum source can also be connected to the slurry feed line 4;13; 19/21; 120/121 to remove any slurry left in the feed line when operation of the spreader is halted. This may be done by a valve mechanism (electrically or hydraulically operated) which controls opening of the vacuum source to the feed line or diversion of the vacuum from the nozzles 5. The vacuum line is isolated from the feed line during application of IE 000116 slurry. The positive displacement pump 77 may be turned off while the vacuum pump 81 is used to fill the tank body 73.

Figure 7a shows a front view and a side view of a nozzle 5 in detail. It will be seen that the nozzle aperture 41 is at the side rather than the tip, and that the nozzle '' includes a projecting hood 44 defining an open space 43 in front of the nozzle when in the ground. The nozzle 5 may be used in any of the rollers described herein.

Figure 7b shows a variant, the nozzle 50 is inclined which facilitates entering and leaving the ground.

Figures 8 and 9 respectively show an alternative rotor 14 and stator 17. Figure 10 shows the assembled arrangement of the rotor 14 and stator 17. The rotor 14 is partcylindrical in shape with a side wall 200 which has a series of apertures 201 passing from the exterior of the side wall 200 to its interior. A disc 202 is fixed to the side wall 200. The disc 202 has a central bearing housing 203 which is fastened to the disc 202 by fasteners 204. The bearing housing 203 holds a bearing 205 which allows the rotor 14 to rotate axially, and is also employed to locate the rotor 14 on the axle 90 of the roller 1. A groove or recess 206 is formed about the internal surface of the side wall 200 and follows an internal circumference of the rotor 14. The groove is bounded on either side by raised ring portions or walls 207. The apertures 201 may each be screw threaded for engagement with screw threaded pipe fittings etc. The stator 17 comprises two brackets or shoes 208 disposed on either end of an adjustable frame 230. The frame 230 holds the shoes 208 in a disposition which allows the shoes to slot into the groove 206 in the rotor 14, as shown in Figure 10. The shoes each have a pad 209 of sealing material (such as nylon) to provide a reliable seal between the shoes and the groove 206. The stator 17 further comprises a vacuum nozzle 210 which leads to an vacuum aperture 211 in the shoe 208. In the embodiment shown the lower pad 209 is split into two portions 212 and 213, the break between the two portions 212, 213 coinciding with the vacuum aperture 211. Slurry is supplied to a nozzle 214 which opens to a slurry aperture 215, in IE 000116 the pad portion 213. The shoes 208 and pads 209 resemble a brake shoe and brake pad arrangement found in the wheel assembly of motor vehicles.

The stator 17 has two arms 21 forming part of the frame 230 which are adjustable by means of an extension arrangement 217. The arrangement 217 allows the stator to be extended/retracted for fitting to, or removal from the rotor 14. Alternatively the arms 216 could be telescopic and biased towards an extended position so that a reliable seal is maintained between the stator and rotor.

The assembled stator/rotor is shown in Figure 10. The rotor 14 is attached to the axle 90 by fasteners 220 of the roller and rotates with the rolling motion of the roller. The stator 17 does not rotate and accordingly the slurry aperture 215 and the vacuum aperture 211 move into and out of register with the apertures 201 in the rotor in turn. The apertures 201 are connected one to each nozzles 5 by a series of pipes such as in the arrangement of Figure 2. Optionally a cover may be provided in the form of a disc or such like, for covering over the stator once it has been placed in position in the rotor. Apertures 221 in the stator may be used to fix the stator against rotation with the rotor. It will be noted that the vacuum aperture 211 is dimensioned to provide a vacuum across the entire groove 206 in the stator. This keeps the groove 206 free of debris. The stator/rotor arrangement from a simple yet reliable slurry distribution mechanism and also provides a mechanism for applying a vacuum to the nozzles for sucking back slurry from the nozzles.

Figure 11 shows an alternative arrangement for providing a seal (which is adjustable) between the rotor 14 and stator 17. A nylon collar or sealing washer 36 is fixed to the end of a slurry feed pipe 38 and is biased against the rotor 14 (not shown) by a spring 39 which engages with a flange 37 on the pipe 38. The pipe 38 is held on the stator 17 by a bracket 40 through which the pipe 38 extends. The pipe 38 also extends through a second adjustable bracket 46 which is used to trap the spring 39 between itself and the pipe flange 37. The pressure exerted by the bracket 46 on spring 39 and thus on pipe 38 and nylon collar 36 can be adjusted by means of two bolts (not IE 000116 shown) which connect bracket 46 to the stator. Thus the degree to which the nylon collar 36 is biased against the rotor 14 can be adjusted.

In all of the variants described and illustrated it may be advantageous to pass the slurry through a chopping unit (not shown) to chop the slurry before it reaches the nozzles so as to further reduce the risk of clogging. For instance the slurry can be passed through a chopping unit as it is being loaded into the spreader. The chopping unit chops the slurry reducing the size of fibres, in particular, which are normally found in slurry. This helps to avoid blockage of the nozzles and/or the apertures in the rotor/stator as shorter fibres are less likely to become entrapped.

An optionally retractable cover or hood may be fitted over part of or the entire slurry spreader. The scraper 114 may be provided as part of the hood or cover.

In the most preferred arrangement the spreader comprises the arrangement shown in Figure 6 with two rollers fitted to the rear of the tanker 72. Suitably each roller receives an equal vacuum and slurry pressure from the tanker. Each roller has four rows of nozzles 5; each row having eight nozzles. Each row is arranged in a parthelical pattern. The nozzles 5 have a length of 127 mm, and an internal diameter of 27 mm. The aperture in the nozzle has the dimensions 15 mm by 35 mm. The pressure of slurry supplied to the rollers is typically in the range 10s Pa to 6.0 x 105 Pa (1.0 to 6.0 bar). The vacuum supplied creates a negative pressure of 4.0 x 104 Pa (0.4 bar). Suitably the spreader is towed so that the rollers undergo 8.26 revolutions per minute. The output of such a spreader is typically 4,600 gallons per acre.

Other variants are possible, the aim is to provide consistent even spreading of slurry on the ground, to reduce or eliminate clogging, to reduce or eliminate slurry flow from nozzles not in contact with the ground, and to provide a roller which rolls evenly over the ground.

IE 000116 - ' 17 In use both the displacement pumps 77 and the vacuum pump 81 are operational. The pump 77 supplies slurry to the roller 79 which inject the slurry into the ground.

The vacuum pump 81 sucks back slurry left in the nozzles after injection and returns it to the tank body 73 via the primary trap 87 or the secondary trap 85. In operation the valve 113 is open. The traps 87 and 85 prevent slurry being sucked into the vacuum pump 77.

To fill the tank body 73 with slurry, the valve 113 is closed, a slurry pipe is connected to the intake valve 112, and the vacuum is used to suck slurry into the tank in a conventional manner.

The words “comprises/comprising” and the words “having/including” when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

From a consideration of the foregoing description and drawings, it will be appreciated that the slurry spreader according to the invention is simple in construction, reliable in operation, and will cause little if any damage to the soil on which slurry is being spread.

Claims (24)

1. A slurry spreader comprising : (a) a roller (l;10; 79) which rolls along the ground which has an array of projecting nozzles (5) for penetrating the soil and injecting slurry into the soil; (b) a slurry distribution mechanism which operates automatically as the roller (l;10; 79) undergoes its rolling motion so as to distribute slurry to nozzles (5) which are oriented downwardly; and (c) a mechanism for applying a vacuum from a vacuum source to the nozzles for sucking slurry back from the nozzles (5).

2. A slurry spreader according to claim 1 wherein the slurry is distributed only to nozzles which are oriented downwardly, and preferably wherein slurry is supplied to nozzles which are oriented downwardly for penetrating the soil, for example, the supply of slurry being effected when the nozzle is close to, but not at, its lowermost position.

3. A slurry spreader according to Claim 2 wherein the slurry is distributed to nozzles which have passed through the lowermost position.

4. A slurry spreader according to any preceding claim wherein the distribution mechanism and the mechanism for applying the vacuum are operable in a continuous cycle.

5. A slurry spreader according to any preceding claim wherein the vacuum mechanism and the distribution mechanism are operable simultaneously.

6. A slurry spreader according to any preceding claim wherein the mechanism for applying a vacuum exposes a nozzle (5) to a vacuum immediately after the distribution mechanism has supplied slurry to the nozzle (5) and it has been injected into the ground. IE 000116

7. A slurry spreader according to any preceding claim wherein the distribution mechanism supplies slurry to one nozzle (5) at a time.

8. A slurry spreader according to any preceding claim wherein the mechanism for applying a vacuum is adjustable so as to apply vacuum to one or more nozzles (5) at a time.

9. A slurry spreader according to any preceding claim wherein the mechanism for applying a vacuum applies a vacuum to one nozzle (5) at a time.

10. A slurry spreader according to any preceding claim wherein the nozzles (5) are arranged so that each nozzle (5) is a circumferential distance apart from the others about the roller (l;10;79).

11. A slurry spreader according to any preceding claim wherein the nozzles (5) are arranged in a helical or part-helical pattern, or a series of helical or part-helical patterns.

12. A slurry spreader according to any preceding claim wherein the slurry distribution mechanism comprises a stator (17) having an aperture (18; 215) connected to a slurry supply and a rotor (14) having a plurality of apertures (15;201) connected to the nozzles (5) each aperture (15;201) in the rotor (14) being brought into register with the aperture (18;215) in the stator (17) during rolling motion of the roller (1 ;10;79).

13. A slurry spreader according to any preceding claim wherein the mechanism for applying a vacuum comprises a stator (17) and a rotor (14) the stator having an aperture (61;211) connected to a vacuum supply and a rotor (14) having a plurality of apertures (15) connected to the nozzles (5) each aperture (15) in the rotor (14) being brought into register with the aperture (18) in the stator (17) during rolling motion of the roller (l;10;79). IE 000116

14. A slurry spreader according to claim 12 or Claim 13 wherein the rotor (14) is part-cylindrical in shape and having an internal annular groove (206) about an internal circumference, the apertures (201) in the rotor (14) passing from the internal surface of the groove to the exterior of the rotor, the stator being adapted for engagement in the 5 groove (206), the slurry and vacuum apertures (215;211) in the stator being arranged to come into register one by one with the apertures (201) in the rotor, on rotation of the rotor.

15. A slurry spreader according to any one of claims 12 to 14 wherein the slurry 10 distribution mechanism and the mechanism for applying a vacuum comprise the same - stator (17) having an aperture (18;215) connected to a slurry supply and an aperture (61;211) connected to the vacuum source and the same rotor (14) has a plurality of apertures (15 ;201), each aperture (15;201) in the rotor being brought in turn into register with the aperture (161;211) in the stator connected to the slurry supply and then the 15 aperture (15) in the stator connected to the vacuum source during rolling motion of the roller (l;10;79).

16. A slurry spreader according to any one of Claims 12 to 15 wherein a seal is provided between the stator and the rotor.

17. A slurry spreader according to Claim 16 wherein the seal is provided by a gasket optionally constructed of plastics material such as nylon.

18. A slurry spreader according to Claim 17 wherein the gasket is formed by a collar 25 recessed in a groove in the rotor or the stator.

19. A slurry spreader according to Claim 18 wherein the collar is located in a groove on the rotor and mates with an annular recess on the stator to form a seal. 30

20. A slurry spreader according to any one of claims 12 to 19 wherein the apertures in the rotor are elongate. IE 000116

21. , A slurry spreader according to any one of claims 1 to 20 wherein the slurry spreader comprises a bank of rollers (l;10;79) optionally arranged side by side. 5

22. A slurry spreader according to any one of claims 1 to 21 wherein the slurry spreader further comprising a slurry tanker (72).

23. A slurry spreader according to claim 22 wherein the tanker (72) and/or spreader comprises a pump for supplying slurry to the spreader and/or a vacuum pump which 10 provides a vacuum source.

24. A slurry spreader substantially as described herein with reference to and as illustrated in the drawings.