GB2623874A - Dribble boom - Google Patents

Abstract

A dribble boom for slurry distribution comprises a tubular boom 210; means for attachment of the tubular boom to a slurry tanker; a conduit (130, fig 2) for providing fluid communication between slurry tanker contents and the boom, the tubular boom 210 having a plurality of orifices 240 along its length as outlets for slurry; a shaft (150, fig 8) extending through the length of the boom and a motor configured to rotate the shaft. The shaft has one or more appendages 240, 260 configured to rotate within the tubular boom. The appendages may be paddles 240, 260 wherein the paddles may be disposed at an angle between 0 and 90 degrees, preferably the angle maybe 45 degrees in the form of an Archimedes screw. The paddles may have a flexible rim that passes over a respective orifice. The motor maybe configured to cause the shaft to oscillate longitudinally along the length of the boom. The orifices 240 can be raised from the surface of the boom and protected by wear blocks 242. The wear blocks 242 can prevent stones from blocking the orifaces.

Description

Dribble Boom

Background

Slurry is often used as a fertiliser in agriculture. The 5 combination of its availability from farm animal waste and its efficacy as a fertiliser makes it a go-to choice for many farmers.

When it comes to distributing the slurry onto the land, the traditional method is to distribute using a splash plate slurry spreading technique. In this method, slurry from a tanker is fired at an angled splash plate, causing the slurry to be redirected and sprayed out in a fan like manner.

Whilst this has historically been the method of choice, it comes with many associated disadvantages. By sending the slurry 15 through the air in a partially vaporised manner, the slurry experiences ammonia losses of between 80% and 100% whilst airborne. This drastically reduces the amount of nitrogen available for crops in the fertilised ground and therefore reduces the efficacy of the slurry. Further, approximately 88% of ammonia emissions in the UK come from agriculture. This loss of ammonia therefore not only negatively impacts potential crop yield by rendering the slurry a less nutritious fertiliser, but contributes to the pollution of our atmosphere. Another downside of this traditional method is the odour, the smell from 25 the slurry can be carried long distances in the area as a result of its partial reduction to vapour.

To counteract this problem, low emission slurry spreading equipment has been developed to reduce the ammonia loss. These include the trailing hose spreading system, sometimes referred 30 to as a dribble bar. Slurry is pumped from the tanker and into a number of small diameter hoses. These hoses distribute (dribble) slurry onto the ground. To minimise ammonia loss, the tubes are kept as close to the ground as possible.

Another low emission slurry spreading method is the trailing shoe slurry spreading system. This is similar to the trailing hose system; however, it includes "shoes" that ride along the ground to part the vegetation and ensure that the slurry is deposited onto the soil as opposed to on top of the crops.

Yet another low emission slurry spreading mechanism is 10 "slurry injection systems". In these systems, cutting discs cut troughs into the ground and the slurry is poured from tubes into these slots.

The above-mentioned low emission systems all require the slurry to be finely separated, chopped or macerated prior to use to reduce the chances of the low diameter tubes becoming blocked. Further, these methods also require pumping of the slurry from the tanker into the tube. Both these steps require time and power to achieve and if not performed correctly cause inefficient spreading, such as from blockage.

There is a need in the art for systems and methods of slurry distribution which reduce ammonia losses to the atmosphere, but do not require as much energy input and have less risk of blockage and other defects.

Summary

The present invention in its various aspects is as set out in the appended claims.

As such, the present invention provides an apparatus for slurry distribution. The apparatus comprising: a tubular boom; 30 means for attachment of the tubular boom to a slurry tanker; a conduit for providing fluid communication between slurry tanker contents and the boom, the tubular boom having a plurality of orifices along its length as outlets for slurry; a shaft extending through the length of the boom and a motor configured to rotate the shaft. The shaft comprises one or more appendages configured to rotate within the tubular boom.

The shaft is preferably hydraulically driven, this allows for high resistance without motor burnout or stalling.

As such, the present invention provides means for slurry to be taken from the tanker and distributed onto the ground.

The shaft is preferably configured to rotate at a low rpm speed of shaft compared to a macerator. As such the invention has the advantage of lower power consumption and reduced maintenance over prior art examples using a macerator. Preferably the shaft rotates at between 60 and 300rpm. This reduces the power input required.

In prior art examples, the slurry must be pumped from the top of the tanker as the slurry must travel through metres of small diameter (50mm diameter) pipes, such pipes provide resistance to flow and the potential for blockage.

Preferably the slurry is pumped into the dribble boom via the conduit, the pumping action being provided by a pump that is present on the tanker. Slurry tankers in general have such a pump in situ and the pump may be turned from vacuum to pressure through the use of a valve.

Advantageously for the present invention a pump in the slurry tanker for pumping the slurry from the tanker into the boom, may be omitted as the shaft and paddles in the boom can provide sufficient pumping, thus reducing complexity and increasing reliability. In this respect advantageously the conduit can be, and is preferably connected to the base of the tanker and therefore the boom can be gravity fed.

The apparatus may further comprise a plurality of dribble tubes, each tube attached at a proximal end to the tube boom at one of the orifices, the tubes being open at a distal end. These dribble tubes serve to direct the slurry and deposit it closer to the ground, reducing the ammonia loss and the intensity of the odour associated with slurry spreading. The dribble tubes may preferably be between band 60 cm in length. The short length of the tubes reduces the chance of blockages.

The dribble tubes are preferably between 25 and 75 ram in 10 diameter. The small diameter allows the slurry to be distributed accurately, reducing the amount of slurry deposited on crop leaves.

The boom is preferably between 2.5 and 36 m in length.

The dribble tubes preferably have a diameter larger than the diameter of the orifices. This ensures that anything that passes through the orifices will certainly be able to pass through the dribble tubes, reducing the chances of a blockage occurring in one of the tubes.

The apparatus may further comprise a plurality of wear blocks associated with the orifices and located between the appendages and the orifices. By including wear blocks in the booms between the appendages and the orifices the advantage is provided that the blocks extend the orifices up above the bottom surface of the boom meaning that denser materials such as rocks are less likely to come into contact with the orifices, reducing the chances of blockages occurring and encouraging the stones towards the stone traps at the end of the boom. Furthermore, the wear blocks can be easily replaced in the event of them becoming worn by the interaction of stones with the appendages.

In a preferred embodiment a gap is provided between the wear blocks and the appendages. That gap is preferably between 2 and lOmm and ideally 5mm. A small gap between the appendages and wear blocks that is anything between 3 and 40%, and ideally 10%, of the diameter of the tube minimises the wear between the appendages and the wear block that results from stones mixed into the slurry and reduces the chances of stones becoming jammed into the orifices.

The dribble tubes may be flexible. This allows the tubes to be positioned closer to the ground. Variations in the surface will be less likely to damage flexible tubes, therefore the tubes can be positioned closer to the ground.

Alternatively, the dribble tubes may be rigid. This is more suitable with the distal end of the dribble tubes further comprising a shoe configured to keep the dribble tube distal end on the floor and also configured to part the grass or crop to get the slurry on the surface of the soil and avoid contact with crop leaves. The shoe is preferably positioned on the side of the tubes that will face in the direction of travel in use.

As a further alternative the apparatus may further comprise a plurality of cutting discs equal to the number of dribble tubes, the cutting disks disc configured to cut a line into soil, wherein each dribble tube is configured such that its distal end is proximate to its associated disk. This provides deeper penetration of nutrients into the soil, making it more readily available for roots and further reduces ammonia loss to the atmosphere.

Preferably the plurality of orifices are spaced equally along the length of the boom. This allows for even slurry distribution. The shaft and appendages enable such distribution to be even in contrast to multiple pipe systems each pipe being of different length or with a boom with no shaft and appendages.

The appendages are preferably paddles. The paddles will churn the slurry and assist its movement through the boom. The paddles may preferably extend between 4 and 15 cm from the centre of the shaft.

Preferably, there are an equal number of orifices to paddles and the paddles are each positioned such that they pass 5 over, i.e., sweep over a respective orifice as the shaft rotates. As such, the paddles effectively clean the orifices each time the shaft rotates. If matter such as lumps or stones have become stuck over an orifice, then the paddles will dislodge the stuck matter, unblocking the orifice and allowing free flow of slurry. 10 This provides the benefit that there is no need for maceration of the slurry prior to spreading. The invention allows for the orifices to be cleaned by the paddles, preventing blockages.

Preferably at least one paddle is positioned within 30cm of the conduit. Paddles positioned close to the conduit in this 15 way may provide a cutting and/or macerating effect to the slurry that comes from the conduit.

The paddles may be disposed at an angle of between 0 and 90 degrees to the shaft.

The paddles may preferably be disposed at an angle between 20 S and 85 degrees to the longitudinal axis of the shaft. Further preferably, the angle is between 20 and 70 degree and ideally the angle is 45 degrees. Having the paddles disposed at an angle to the shaft in this manner provides that the paddles can unblock the orifice in a single rotation whilst having the 25 further benefit of drawing the slurry along the boom.

Alternatively, the paddles may be disposed at an angle of 85 to 90 degrees to the longitudinal axis of the shaft. In this case the paddles perform a slicing action cutting up any lumps covering the orifice. Stubborn lumps may therefore be reduced in size gradually until they are small enough or break up enough to go through the orifice.

As a further alternative, the paddles may be disposed at an angle between 0 and 5 degrees to the shaft. 0 degrees here meaning parallel to the shaft.

The paddles may each have a flexible rim on the edge of the paddle that passes over the respective orifice. This prevents the paddles from becoming damaged if stones are blocking the orifice, and also provides the benefit that the paddles can have contact with the orifices. That is, they sweep over in contact.

The paddles may have a metal rim. Such paddles may be used 10 to slice lumps in the slurry into smaller pieces.

The paddles may have removable rims. This allows the rims to be replaced if damaged.

Instead of paddles, the one or more appendages may be an Archimedes screw. In this case, the appendages transform the shaft into an Archimedes screw, as the shaft rotates, slurry will be drawn along the boom, the screw blade will also pass over the orifices, removing any blockages.

The appendages may each be portions of an Archimedes screw between 10 and 250cm in length. This provides a balance between 20 pumping and ensuring equal spread of slurry through the dribble tubes.

The orifices may comprise a raised lip on an internal surface of the boom. This prevents larger objects from becoming trapped in the orifices and encourages the liquid component of the slurry to exit the boom through the orifices. These orifices protrude into the shaft and as such are less readily blocked by stones (for example) as such objects cannot then 'drop in' to the orifices as the orifice is proud of the boom wall.

The protruding portion of the orifices may comprise a 30 removable collar. This collar may be affixed to and proud of the raised lip at the point of the lip most proud of the internal

S

wall of the boom. As such the collar can ensure that the point most proud of the boom wall is replaceable in case of damage.

The motor may be positioned at the centre or Inboard end of the boom. This prevents the motor from becoming damaged if 5 the end of the boom is knocked.

The cross section of the tubular boom may be rectangular. This allows for stones to collect in at least one of the corners of the rectangle, away from the appendages.

Alternatively, the cross section of the tubular boom is rectangular with a semicircle at one of the short ends of the rectangle, the shaft configured to pass through the centre of the diameter of the semicircle. This provides space above the shaft for slurry to move. In this case the appendages may be configured to wipe over the semi-circular portion as the shaft rotates.

The motor may be configured to rotate the shaft in both clockwise and anticlockwise directions as selected by a user. If there ever were to be a blockage, reversing the motors may help to unblock the system by moving the appendages in the opposite direction. This can, with angled appendages produce revers pumping action to free up any blockage.

The motor may be configured to cause the shaft to oscillate longitudinally along the length of the boom. This may be instead of, or in addition to the rotation of the shaft. This serves 25 to further agitate the slurry, preventing blockages.

The Motor may preferably be housed within the tubular boom. This protects the motor from the elements and external impact.

The motor may be alternatively housed external to the tubular boom. To keep the motor separate from the slurry reducing the risk of motor failure.

The tubular boom may comprise one or more removable panels. The panels may preferably be on a side of the boom that will face substantially towards the ground when the boom is in use. This will allow for stones and other items too large to fit through the orifices to be removed from the boom.

The apparatus of any preceding claim further comprising a stone collection compartment at the opposite end of the boom to the motor. The stone collection compartment may be an area at the end of the boom having increased volume (such as radially).

The motor preferably propels the slurry away from the motor i e., as mediated through the motor rotating the shaft on which the propelling means (such as the appendages are located The boom may preferably be configured to separate at its centre point so that the resulting halves of the boom can be raised for transportation. In addition to increased ease of transportation, raising the halves of the boom will allow any stones or large waste moved on by the paddles to fall out of the boom. In this case, it may further be preferable that the motor is housed in the centre of the boom, between the two halves so as to drive the slurry away from the motor, down the boom and to the orifices.

Alternatively, the boom may be a 3 section boom. In this configuration a centre section remains attached to the tanker and may be lifted enough to clear the ground for transportation.

The two remaining portions are disposed either side of the centre section and configured to be raised for transportation. This configuration reduces the overall transport height and avoids breakages on tree branches etc. One or more sections of the boom may preferably be bi30 folding so as to reduce transport size. This is especially of use in cases where the unfolded boom is 24 to 36m wide. The apparatus may include a "break back system" which allows the boom to fold back, substantially parallel to the ground, if an obstruction like a tree or pole is struck by the boom.

This prevents damage to the boom from such impacts. It is preferable that the apparatus is configured to be pulled behind a tanker as it moves in a forward direction. However, it is envisaged that the apparatus be positioned ahead of the tanker as it moves forwards.

The boom may be configured, in use, to slope downwards on each side from its centre point.

This encourages the gravity feed of the orifices and helps to ensure stones fall to the end of the boom. In this case it may be further preferable that any dribble tubes vary in length so that they all terminate at the same distance from the ground/all trail on the ground to the same extent.

The boom may be configured to be rotatable, such as centred on an outlet from a tank, to an upright posture for transport and storage.

The apparatus may additionally include one or more attachment means for securing the apparatus to a slurry tanker. 20 This may be in the form of a tube acting both as conduit and pivot point for simplicity of construction.

The apparatus may additionally or alternatively include means of attaching the device to an umbilical system such that there is be fluid communication between slurry in a static tank and the boom via a flexible (umbilical) pipe. The slurry will then be pumped directly from the static tanker and into the boom.

The apparatus may further Include a hose reel unit to reel off the flexible pipe of the umbilical system to prevent tangles in the pipe.

In another aspect, the present invention provides a slurry tank towed by and powered by a farm tractor and the apparatus as described above.

In another aspect, the present invention provides a self-5 propelled slurry tank pulling the apparatus described above.

Detailed Description

The following description references the following figures: Figure I Boom according to the present invention attached to a 10 slurry tanker being pulled by a tractor.

Figure 2 Boom according to the present invention attached to a slurry tanker being pulled by a tractor.

Figure 3 Boom according to the present invention attached to a slurry tanker being pulled by a tractor.

Figure 4 Boom according to the present invention attached to a slurry tanker being pulled by a tractor.

Figure 5 A cross section of a boom according to the present invention with dribble tubes.

Figure 6 the cross section of figure 5 in a perspective view.

Figure 7 A cross section of a boom according to the present invention with dribble tubes.

Figure 8 the cross section of figure 7 in a perspective view.

Figure 9 A cross section of a section of a boom according to the present invention.

Figure 10 A close up of an orifice and appendage according to the present invention.

Figure 11 A close up of an orifice and appendage according to the present invention.

Figure 12 A cross section of a boom according to the present invention.

Figure 13 A stone trap according to the present invention.

Figure 14 End view of a boom of an alternative embodiment of the 5 present invention.

Figure 15 Perspective end view of boom of the alternative embodiment of figure 14.

The present invention will now be described in terms of the following features.

In the description, like features are assigned like numerals.

Apparatus Boom Dribble tube Conduit 140 Orifice Shaft Paddle Raised lip 180 Stone trap Figure 1 shows an apparatus 100 attached to a slurry tanker being pulled by a tractor. The apparatus 100 comprising a boom 110, and a plurality of dribble tubes 120 attached to the boom. The apparatus further comprises a conduit 130 that provides fluid communication between a slurry tanker (pictured) and the boom 110. In figure 1, the apparatus is in position for distributing slurry, with the dribble tubes 120 below the boom, the distal ends of the dribble tubes proximal to the ground.

Figure 2 shows the apparatus 100 of figure 1 in a position for transit. The boom 110 is separated into 2 portions and the two portions have been raised to reduce the overall width of the apparatus thus allowing it to be transported on roads between

fields.

Figure 3 shows the apparatus 100 of figure 1 in a side on view. Here it is seen that the boom 100 is parallel to the ground when in use. The distal end of the dribble tubes 120 are directed towards the ground at a 45 degree angle to the ground.

However, it is envisaged that any angle between 90 degrees (vertically downward), and 10 degrees would be suitable.

Figure 4 shows the apparatus 100 of figure 2 in a side on view. The boom 110 is separated into 2 portions and the two portions have been raised to reduce the overall width of the apparatus thus allowing it to be transported on roads between fields.

Figures 5 and 6 show an example boom 110 according to the present invention. Figure 5 shows a cross section, and figure 6 shows the cross section in perspective view. In this case, the cross section of the tubular boom 110 is rectangular with a semicircle at one of the short ends of the rectangle, the shaft 150 is passing through the centre of the diameter of the semicircle. Paddles 160 can be seen extending from the shaft 150. The paddles are quarter circular in shape and configured to match the curvature of the boom 110 on the paddle's circumferential side.

Each paddle is configured to pass over an orifice 140 as the shaft rotates. This is more clearly seen in figure 6 where the separation between the paddles 160 is more easily seen. A dribble tube 120 extends from each of the orifices. The diameter of the dribble tubes is larger than the diameter of the orifices to ensure that matter that passes through the orifices will be able to pass through the dribble tubes.

Each paddle 160 is preferably disposed 90 degrees around the shaft from the paddles 160 either side. This creates a helical arrangement of paddles 160 that can assist in the transport of slurry along the boom.

The paddles are shown having bolt-on removable edges. This is optional and provides the benefit that the paddles can easily be more easily repaired if their edges become damaged.

Figures 7 and 8 show an example boom 110 according to the present invention. Figure 7 shows a cross section, and figure 8 shows the cross section in perspective view. In this case, the cross section of the tubular boom 110 is rectangular.

Paddles 160 can be seen extending from the shaft 150. The paddles 160 are quarter circular in shape and configured to pass over the orifice 140. The orifice 140 in this case further comprises a raised lip 170 to raise the orifice 140 away from the internal surface of the boom 110. This has the benefit of providing a region below the orifice in which stones or larger matter in the slurry can rest if it cannot pass through the orifice. A dribble tube 120 extends from each of the orifices. The diameter of the dribble tubes is larger than the diameter of the orifices to ensure that matter that passes through the orifices will be able to pass through the dribble tubes.

Figure 9 shows a boom with the cross section of the boom shown in figures 5 and 6 with the back plate of the boom 110 removed. Here the spacing between the paddles 160 along the shaft 150 can be seen. The spacing of the paddles 160 is equal to the spacing between the dribble tubes 120.

Preferably the space between the dribble tubes is between and 50 cm.

Figure 10 shows a close up of a paddle 160 attached to a shaft 150 and passing over an orifice 140. The Orifice provides fluid communication between the inside of the tubular boom and the dribble tube 120 associated with the orifice 140. In this case, the paddles are set at an angle to the shaft of approximately 45 degrees. This is an example angle, and any angle between 0 and 90 degrees is envisaged. Preferably the angle is between 20 and 70 degrees.

Figure 11 shows an alternative arrangement to figure 10.

Figure 11 shows a close up of a paddle 160 attached to a shaft 150 and passing over an orifice 140. The Orifice provides fluid communication between the inside of the tubular boom and the dribble tube 120 associated with the orifice 140. In this case, the paddles are set at an angle to the shaft of 90 degrees (perpendicular to the shaft. Instead of, or as well as rotating, the shaft 150 is configured to move side to side as indicated by the arrows on the figure. The shaft 150 moving in this way causes the paddle 160 to move back and forth across the orifice 140, dislodging stones and matter too large to pass through the orifice and pushing suitable matter through the orifice and into the dribble tube 120.

Figure 12 shows the arrangement of figure 11 extended across the length of the boom 110.

Here it is seen that when the shaft oscillates back and 25 forth as in figure 11, the paddles 160 are all disposed along over orifices 140 as opposed to being disposed helically around Lhe sha L 150 as in for example, figure 6.

Figure 13 shows an end of a boom 110 having a stone trap 180. The stone trap comprises an area of higher volume at an end of the boom 110. Any matter that cannot pass through an orifice 140 into a dribble tube 120 will travel along the boom 110, aided by the rotation of the paddles 160 until they come to rest in the stone trap. The stone trap provides an area for the larger lumps of matter present in the slurry to rest in without causing damage or blockages. Having a stone trap increases the amount of time the apparatus can be used for before 5 the stones have to be removed.

Referring now to figures 14 and 15, an alternative embodiment of the present invention is shown in which equivalent features are indicated with like reference numerals increased by 100. The apparatus 200 operates in the manner set out above but some features are structurally different. For example, the bottom surface 212 of the boom 210, this being the surface that contains the orifices 240, is provided with wear blocks 242 which surround each orifice. The wear blocks 242 are easily replaceable components formed from cast steel which makes them hard wearing and easy to mass produce at a low cost. Eventually, these plates will become worn as a result of the interactions of stones and the like and the moving paddles 260 and can be replaced. The wear blocks 242 also lift the orifices 240 away from the bottom surface 212 meaning that larger and denser particles, such as rocks and stones, are likely to sink and move along that bottom surface 212 by the flow of slurry, to be collected in the stone trap (not shown in figures 14 and 15). The stones are therefore kept away from the paddles and orifices reducing the likelihood of damage to either of these components.

The paddles 260 are formed from steel with a straight outer edge 262, this being the edge closest to the wear block 242. There is small gap, typically between 2 and 10mm and ideally 5mm, between the edge 262 of the paddle 260 and the wear block 242. As a result, the damage on the wear blocks is limited to that caused by material larger than 5mm getting between the paddles 260 and the block 242. It should also be noted that with the design of the embodiment in figures 14 and 15 and that in the previous embodiment, there is significant space within the boom around the paddles and in particular above. This is because the primary purpose of the movement of the paddles is not to move the slurry along the boom, this is achieved by the pressure from the tank (gravitational or pumped) causing the boom to substantially fill. Instead, the paddles are primarily for ensuring that the orifices do not get blocked by the inevitably present lumps of solid material by forcing such lumps to be broken up and pass through the orifices. To further assist with this purpose the hydraulic motor which drives the axel carrying the paddles 260 can be reversed in order to dislodge any stones which become jammed in the orifices against the rotation of the paddles.

In the extremely rare cases where a blockage does occur within the boom 210, a series of windows 214 are provided to 15 give access to the inside of the boom to allow any such blockages to be cleared and for servicing of the apparatus to be performed.

It will be appreciated by persons skilled in the art that the above embodiments have been described by way of example only and not in any limitative sense, and that various alterations and modifications are possible without departure from the scope of the protection which is defined by the appended claims. For example, in the above embodiment the motor is located at the centre of the apparatus between the two boom portions. However, the motor could be located in any suitable position including at the ends of the booms or partially along the length of the boom.

Claims (25)

1. Claims 1. Apparatus for slurry distribution comprising: a tubular boom; means for attachment of the tubular boom to a slurry tanker; a conduit for providing fluid communication between the slurry tanker contents and the boom; the tubular boom having a plurality of orifices along its length as outlets for slurry; a shaft, extending through the length of the boom; 10 a motor configured to rotate the shaft; wherein the shaft comprises one or more appendages configured to rotate within the tubular boom.
2. 2. The apparatus of claim 1 further comprising a plurality of dribble tubes, each tube attached at a proximal end to the tube 15 boom at one of the orifices, the tubes being open at a distal end.
3. 3. The apparatus of claim 2 wherein the dribble tubes have a diameter larger than the diameter of the orifices.
4. 4. The apparatus of any preceding claim further comprising a plurality of wear block associated with said orifices and located between said appendages and said orifices.
5. 5. The apparatus of claim 4, wherein a gap is provided between said wear blocks and said appendages.
6. 6. The apparatus of claim 5, wherein the gap is between 2 and 10mm.
7. 7. The apparatus of any of claims 2 to 6 wherein the dribble tubes are rigid and a distal end of the dribble tubes comprise a shoe configured to keep the dribble tube distal end on the -18 -floor and also parts the grass or crop to get the slurry on the surface of the soil and avoid contact with crop leaves.
8. 8. The apparatus of any of claims 2 to 6 wherein the apparatus further comprises a plurality of cutting discs equal to the number of dribble tubes, the cutting disks disc configured to cut a line into soil, wherein each dribble tube is configured such that its distal end is proximate to its associated disk.
9. 9. The apparatus of any preceding claim wherein the appendages are paddles.
10. 10. The apparatus of any preceding claim wherein there are an equal number of orifices to paddles and the paddles are each positioned such that they pass over an orifice as the shaft rotates.
11. 11. The apparatus of claim 8 or claim 9 wherein the paddles are 15 disposed at an angle between 0 and 90 degrees to the shaft.
12. 12. The apparatus of claim 11 wherein the angle is between 20 and 70 degrees.
13. 13. The apparatus of claim 11 wherein the angle is 45 degrees.
14. 14. The apparatus of any of claims 9 to 13 wherein the paddles 20 each have a flexible rim on the edge of the paddle that passes over the respective orifice.
15. 15. The apparatus of any preceding claim wherein the orifices comprise a raised lip on an internal surface of the boom.
16. 16. The apparatus of any preceding claim wherein the motor is 25 positioned at the centre of the boom.
17. 17. The apparatus of any preceding claim wherein the cross section of the tubular boom is rectangular.
18. 18. The apparatus of any of claims 1 to 15 wherein the cross section of the tube is rectangular with a semicircle at one of -19 -the short ends of the rectangle, the shaft configured to pass through the centre of the diameter of the semicircle.
19. 19. The apparatus of any preceding claim wherein the motor is configured to rotate the shaft both clockwise and anticlockwise 5 directions as selected by a user.
20. 20. The apparatus of any preceding claim wherein the motor is configured to cause the shaft to oscillate longitudinally along the length of the boom.
21. 21. The apparatus of any preceding claim wherein the motor is 10 housed within the tubular boom.
22. 22. The apparatus of any preceding claim wherein the tubular boom comprises one or more removeable panels.
23. 23. The apparatus of any preceding claim further comprising a stone collection at the opposite end of the boom to the motor.
24. 24. The apparatus of any preceding claim wherein the motor propels the slurry away from the motor.
25. 25. Slurry tank towed by and powered by a farm tractor comprising the apparatus of any of claims 1 to 24.-20 -