WO2015082710A1

WO2015082710A1 - Liquid supply unit

Info

Publication number: WO2015082710A1
Application number: PCT/EP2014/076785
Authority: WO
Inventors: Lucas Carlos TALAMONI
Original assignee: Black Soil Global Corp; SMEE, Anthony James Michael
Priority date: 2013-12-06
Filing date: 2014-12-05
Publication date: 2015-06-11
Also published as: BR102014006167A2; AR097803A1; UY35669A

Abstract

A liquid supply unit, for use with an agricultural machine to deliver a liquid to a furrow, comprises: a liquid product inlet for receiving a source supply of liquid product; a pump, arranged to draw the liquid product into the liquid product inlet; and an outlet, arranged to expel the pumped liquid product to a liquid distribution element of the agricultural machine. The liquid distribution element is arranged to deliver the liquid product to the furrow.

Description

LIQUID SUPPLY UNIT

FIELD OF THE INVENTION The present invention relates to a liquid supply unit, for use with (or part of) an agricultural machine to deliver a liquid to a furrow.

BACKGROUND Conventionally, farmers sow seeds in shallow depths of soil where rainwater provides moisture which encourages germination. Following a spell of rain, the farmer starts sowing as soon as possible in order to take advantage of the moisture in the soil. However, this moisture may soon evaporate and so the farmer has a limited opportunity to complete the sowing.

The present invention aims to alleviate at least to some extent one or more of the problems of the prior art.

SUMMARY OF THE INVENTION

The invention is set out in the accompanying claims.

According to an aspect of the invention, there is provided a liquid supply unit for use with an agricultural machine to deliver a liquid to a furrow, the liquid supply unit comprising: a liquid product inlet for receiving a source supply of liquid product; a pump, arranged to draw the liquid product into the liquid product inlet; and an outlet, arranged to expel the pumped liquid product to a liquid distribution element of the agricultural machine, the liquid distribution element being arranged to deliver the liquid product to the furrow.

The liquid supply unit may include a water inlet for receiving a source supply of water, wherein the pump is arranged to draw one of the liquid product and the water into the respective inlet, and the outlet is arranged to expel the pumped liquid product or water to the liquid distribution element of the agricultural machine, the liquid distribution element being arranged to deliver the liquid product or water to the furrow.

The liquid supply unit may include a selector, for example a selector valve, for selecting between the liquid product inlet and the water inlet.

The liquid product may comprise a fertiliser, an inoculant, a fungicide, or an insecticide. The liquid product may comprise water, for example on its own or premixed with one or more other liquids, for example a fertiliser, an inoculant, a fungicide, or an insecticide.

The liquid supply unit may include a store, for example one or more tanks, for storing the source supply of liquid product. The pump may comprise a positive displacement pump, for example a piston diaphragm pump.

The liquid supply unit may include a motor, for example a hydraulic motor, configured to drive the pump. The liquid supply unit may include a flow control unit, for example a hydraulic flow control unit, for controlling the flow rate of the liquid product, optionally at a constant speed. The hydraulic motor and the hydraulic flow control unit may be configured to connect to a hydraulic system or cardanic system of the agricultural machine. The liquid supply unit may include a pump speed indicator, for example a digital pump speed indicator, for indicating the current speed of the pump.

The liquid supply unit may include a pressure sensor for indicating the pressure of the liquid product at the outlet.

The liquid supply unit may include a flow measurer for determining the flow rate of the liquid product, for example the volumetric flow rate or the mass flow rate. The liquid supply unit may include an electro-hydraulic servo valve which is configured to vary the pressure of the pumped liquid product.

The liquid supply unit may include a closure valve which is configured to open or close in order to permit or prevent expulsion of the liquid product from the outlet.

The liquid supply unit may include a controller for controlling respectively the electro-hydraulic servo valve and the closure valve. The controller may include a console for use by an operator to vary the pressure, flow, and/or frequency of application of the liquid product.

The liquid supply unit may include a venting/operating selector which is configured to direct the liquid product to the liquid product source supply, via a branch outlet of the electro-hydraulic servo valve, or to direct the liquid product to the ground, via a venting outlet.

The liquid supply unit may include an agitation tap which is configured to provide a flow of the pumped liquid product to the source supply of liquid product in order to agitate the source supply of liquid product so as to keep the liquid product properly mixed.

The liquid supply unit may include a venting orifice which is configured to connect to an external pump to circulate water through the distribution element of the agricultural machine, when connected to the outlet, in order to clean the distribution element.

The liquid supply unit may include a non-return valve which is configured to prevent the water from escaping from the venting orifice. The liquid supply unit may include a pressure relief valve which is configured to open to expel the pumped water or liquid product if the pressure thereof exceeds a predetermined value. The liquid supply unit may include an element, for example a hose, which is configured to convey the expelled liquid product to the source supply of liquid product. The liquid supply unit may include a suction filter for filtering the liquid product before the liquid product reaches the pump.

The liquid supply unit may include a line filter which is located downstream of the outlet and configured to connect to the distribution element, for example a manifold of the distribution element.

According to another aspect of the invention, there is provided an agricultural machine, for example a sowing machine, comprising a liquid supply unit as described herein above.

According to another aspect of the invention, there is provided an agricultural machine, for example a sowing machine, configured to deliver a liquid to a furrow and including a liquid supply unit, the liquid supply unit comprising: a liquid product inlet for receiving a source supply of liquid product; a pump, arranged to draw the liquid product into the liquid product inlet; and an outlet, arranged to expel the pumped liquid product to a liquid distribution element of the agricultural machine, the liquid distribution element being arranged to deliver the liquid product to the furrow. According to another aspect of the invention, there is provided a method of delivering a liquid to a furrow, comprising: providing an agricultural machine, for example a sowing machine, configured to deliver a liquid to a furrow and including a liquid supply unit, the liquid supply unit comprising: a liquid product inlet for receiving a source supply of liquid product; a pump, arranged to draw the liquid product into the liquid product inlet; and an outlet, arranged to expel the pumped liquid product to a liquid distribution element of the agricultural machine; pumping a liquid product through the liquid supply unit to the distribution element; and delivering the liquid product to the furrow as seeds are placed in the furrow. The pumping and control system makes possible application of liquid products on agricultural ground. In an embodiment it comprises a pump which is driven by a hydraulic motor, one or more inputs and an output of the liquid(s) to be applied, and intelligent valves which function in association with the distribution system. This distribution system is monitored by the computerised control system which has a front with an easily accessible suction filter, one indicator for the speed, and another which indicates the corresponding pressure. A computerised control console gives the operator complete control over the quantity of liquid to be applied, and the frequency of its application. It is highly versatile, and can be fitted on standard farming machinery, using the existing perforation, hydraulic and electrical system of the latter. A "ploughing irrigation" function permits application of water and fertilisers at the same time and in the same physical place where the (direct/conventional) sowing is carried out. The invention is applicable to any sowing machine, e.g. till (conventional), no till (direct), e.g. with sugar cane or fine crops. In a manner which is unique it permits optimum moistening of the area peripheral to the seed, with minimum evaporation of the liquids, unlike conventional irrigation which does not successfully take place at the appropriate moment, at the optimum depth and in the necessary quantity which is a complement to pivot irrigation saving them the initial 40-60 millimetres, for underground irrigation is fundamentally necessary saver to guarantee start up germination. It is difficult to define the number of days of moisture because this depends on factors such as temperature, soil coverage, soil compaction, porosity, etc, but it is thought that approximately 15 to 25 days without significant evaporation is likely, and the invention provides seed germination and underground moisture. Soil coverage is the most important factor because the coverage protects the soil from the sun and maintains moisture for a long time in the soil.

This "ploughing irrigation" system makes it possible to comply with the necessary sowing dates and maintain moistening which makes possible germination of all of the seeds, without depending on rain in the first few weeks. This increases considerably the yield of the entire sowing process, and makes the system unique.

The "ploughing irrigation" function which permits irrigation in linear form with a capacity from 3000 to 100 litres, which is sufficient to apply the necessary water to irrigate the 19,230 linear metres which exist in 1 hectare (0,52 centimetres between lines).

The system permits application of liquid fertilisers in a totally controlled manner. By this means it is possible to maintain precise and exact control of the products to be applied, in order to comply with the necessary sowing dates and obtain immediate availability of the fertilisers. This "liquid sowing" allows the liquids applied (water or fertilisers) to be in direct contact with the seed, and to provide the ground with the necessary micro-nutrients in a manner which is far more effective than the conventional systems using solids. Not disregarding that liquid fertilizers are mobile in the furrow (granular only 1 cm) and ready to assimilate by the plant. Sowing with granular and applying water in the farrow helps a percentage of granular to be available for the plant. In the case of limited moisture in the furrow, the granular can compete with the seed and absorb the moisture, risking the germination of the seed. This has been proven recently.

Thus it will be seen that the invention comprises a system for pumping and controlling the application of liquid products on ground allocated to agricultural activity, making possible improved use of the productive power of such ground by enhancing the yield of ground of a standard level, and correcting deficiencies of "marginal" sowing areas. Application of liquid on the line makes it possible to optimise the sowing date, to sow with moisture when moisture is lacking, and to keep on sowing when moisture is being lost, and to apply fertilisers and liquids (e.g. inoculants) in the sowing line. 99% germination (from the seed PG) of the seeds implanted in the sowing line can be achieved by means of the moisture which the machine provides in the sowing furrow. (PG is germination power. Each company states the PG on each bag of seed. Some companies sell 95% PG seed bags. Use of the invention can germinate 99%). The invention functions by means of the application of water and fertilising liquids (mixed together or separately) at the same time and in the same physical place where the sowing is carried out, with an irrigation capacity in linear form of 100 to 3,000. For example the quantity may range from 0 to 3,000 Lts with 5 to 30 mm in the sowing line. Consequently, water being the means to add different products to the furrow, the invention makes possible the introduction and definitive establishment of a sowing system consisting of the use of water to guarantee germination and liquid fertiliser to compensate poor soils. The needs and obligations which motivated the design according to the present invention are described hereinafter.

ONE) The first is derived from the need to apply liquid products (water and liquid fertilisers) directly onto the ground during the process of sowing of crops, so as to obtain a better yield (99% germination from the seed PG) from the agricultural activity, thus permitting productive maximisation of regular ground and upgrading and inclusion on the market of marginal areas.

TWO) In turn, during this process, the following information can be controlled electronically:

A - Quantity of liquid used: By this means it is possible to calculate the production costs accurately, precision when carrying out scientific studies can be improved, and the efficiency and effectiveness of treating ground with certain deficiencies and/or defects can be increased.

B - Records of products used: This will make it possible to determine accurately which products are being applied, where they were applied, and with what rate of application (litres/ hectare [Its/ha]), for the purpose of providing statutory reports and scientific or economic analyses of the agricultural activity.

THREE) By this means, and by recording the aforementioned data, the following actions can be applied: A - Application of the liquids on the basis of the studies indicated in section "A", by this means making variations according to the particular needs of each crop, depending on its topographical location, spatial variation and specific yield for each type of ground, in accordance with the deficiencies and defects of this ground, and in accordance with matters relating to parasites or microbes which must be taken into account.

B - Reduction and saving in the amount of water and other liquids used for the treatment of ground, with optimisation of the use of the ground and of the time taken to treat it.

C - When the top soil (10-15 centimetres) is dry, the sowing machine cannot sow and it is necessary to wait for rain to get the top moisture (first 10-15 centimetres). With the invention the farmer can sow any time and not depend on the rain as long as the top moisture is not deeper than 20 centimetres and can quadruple the surface of sowing.

FOUR) Finally, and in line with the reasons and processes indicated, the fourth lies in the need to have constant agitation of the mixture of liquids to be applied, for the purpose of obtaining an appropriate solution or suspension.

The invention makes it possible to introduce the water/liquid products at the same time and in the same place where the sowing is being carried out in the sowing line. The sowing body is designed for a furrow opener (blade which opens up the ground in order to facilitate the entry of the V-disc). The V-disc acts as a protector and double wall where the tube which deposits the seed is located. To this tube which deposits the seed there is coupled the hose for discharge of liquid. For this purpose, the corresponding hoses of the distribution system abut the blades of the sower which perforate the ground and make it possible to deposit the seed from where the seed is deposited in the furrow, where the liquid which moistens and provides humidity all around the seed is applied, then as an option the "beaver tail" is added (that positions all seeds at the same depth, that in the case of corn is very important to geminate at the same time and high so the plants do not compete with each other), or the seed pressing wheel (not recommended) compacts the humidity of the sowing line and then the closing wheels seal the furrow, keeping the humidity intact and available. The system can be controlled by a computerised control system which is responsible for regulating the pressure and flow of liquid supplied by means of its corresponding valves, thus allowing the operator to modify these parameters from the computerised control console (which can be separate from the module). The front of the main module includes a digital display which shows the speed of the pump, and a measurer which shows the pressure and the possibility of carrying out venting of the pump.

In addition, it is possible to add an agitation tank which keeps the liquids correctly mixed. The system has a return which, when the machine is applying liquid, mixes or acts as a beater for the liquids to be applied. When the machine is not applying liquid the return volume decreases depending on the order of the regulating valve. The regulating valve acts as a servo bypass of the return, and that acts as agitation. In the mid-time it is possible to regulate the hydraulic manifold that regulates the hydraulic fluid of the orbital engine and this can increase the volume of water circulating through the pump, increasing the water on the return (more agitation). What is achieved by means of this machine is the application of liquid in the line, providing ploughing irrigation by means of the application of water in the sowing line. BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described, by way of example, with reference to the accompanying figures in which:

Figure 1 schematises an elevated front view of the invention showing the main components which interact physically and visually between the module and the person who is operating it;

Figure 2 schematises an elevated rear view of the invention which shows the main components of the module; Figure 3 shows a computerised control console which may act complementarily with the module of Figures 1 and 2;

Figure 4 schematises an agricultural machine which can be used with/forms part of the invention;

Figure 5 shows a position of moisture around a seed;

Figures 6 and 7 show tables indicating calculations with different furrow distance and water tank capacity; and

Figure 8 shows a table with a comparison between tanks with different volumes. DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

The following elements of the embodiments are identified in the Figures:

a. Suction filter.

b. Digital pump speed indicator.

c. Pressure measurer (0-10 bar or 0-100 kpa) with protection against excess pressure of up to 20 bars.

d. Venting orifice.

e. Source tank selector valve.

f. Venting / operating function selector valve.

g. Piston diaphragm pump.

h. Hydraulic flow control unit

i. Hydraulic motor.

j. Electronic flow measurer,

k. Agitation tap.

I. Non-return valve.

m. Electro-hydraulic servo valve (regulator).

n Electrically operated closure valve.

o Pressure relief valve.

p. Pressure relief valve output.

q. Controlled fluid output.

r. Servo-valve branching output.

s. Venting valve output.

t. Chemical product tank suction orifice.

u. Water tank suction orifice. v. Module case.

1 . Furrow closing disc.

2. Duct where a seed drops.

3. Dual disc.

4. Water channel duct (variable or constant)

5. Moisture in the seed furrow.

Referring to Figures 1 and 2, the main system is contained in a stainless steel case (v) to secure and protect the internal components. Separately, there is the computerised control console (Figure 3) which is connected to the sensors of the module by means of the corresponding cables. This should be positioned in the place preferred by the operator.

Referring to Figure 1 , the front of the system is moulded with a stepped difference in level which separates the lower front part from the upper front part. In this embodiment the lower left area is the source tank selector valve (e), and in the lower right area is the venting / operating function selector valve (f). In the upper right part is located the venting orifice (d) together with the pressure measurer (c). In the upper central part there is positioned the digital pump speed indicator (b). In the upper left part is located the suction filter (a), which is connected to the rear part by means of hoses. This access to the rear part is possible by means of a triangular hole in the front of the case.

Referring to Figure 2, in the rear-upper part there are the connections which come from the front of the module, i.e. the venting orifice hole (d), the pressure measurer tube (c),the cables of the digital pump speed indicator (b), and the hoses of the suction filter (a). In the lower left area is the source tank selector valve (e), and in the lower right area is the venting / operating function selector valve (f).

In the central part is fitted the piston diaphragm pump (g) which is connected to the hydraulic motor (i), and above this is the hydraulic flow control unit (h), with the inputs and outputs to connect to the existing hydraulic system. Adjacent to the pump is the pressure relief valve (o) from which there extends the pressure relief valve output (p). In the centre of the system there are installed the electro- hydraulic servo valve (m) and the agitation tap (k). In the top centre left part there are located the non-return valve (I), the electrically operated closure valve (n) and the controlled fluid output (q).

In the top central lower part, going from left to right, there are the servo-valve branching output (r), the venting valve output (s), the chemical product tank suction orifice (t), and the water tank suction orifice (u), respectively. A piston diaphragm pump (g) with positive displacement makes the liquid circulate. This pump (g) is driven by a hydraulic motor (i) at a constant speed, the maximum value of which is set by the hydraulic flow control unit (h). The digital pump speed indicator (b) shows the machine operator the current speed of the machine. The pressure measurer (c) shows the machine operator the pressure value of the liquid at the output from the pump. The liquid which is impelled by the pump (g) flows through a hose to the electro-hydraulic servo valve (m) and also to the agitation tap (k). This agitation tap (k) can be connected to a tank which contains the chemical products, and provides a flow which permits the agitation of the contents of this tank.

A computerised control system can receive information about the quantity of liquid which is circulating, measured by the flow measurer (j). By this means, the computerised control system sends electric signals to the electro-hydraulic servo valve (m) in order to vary the pressure as required. The electrically operated closure valve (n) opens or closes according to the signals sent by the computerised control system, in order to permit or prevent the flow of liquid to the distribution system via the controlled fluid output (q). The controlled fluid output (q) is monitored by this computerised control system which acts as an interface with the computerised control console. By means of the console the operator can vary the flow, pressure, frequency of application of the products, and other parameters which constitute the requirements of each particular situation. To this controlled fluid output (q) there are connected the hoses of the distribution system through which the liquids circulate until they reach the blades of the sower which insert the seed into the ground and make it possible to apply the liquid products at that same moment.

The source tank selector valve (e) allows the machine operator to switch between two tanks so that one of them is the source of liquid which flows through the pump. The two tanks are connected to the module by means of separate hoses, which are connected to the chemical product tank suction orifice (t) and to the water tank suction orifice (u). The venting / operating function selector valve (f) allows the machine operator to choose whether the flow obtained from the electro-hydraulic servo valve (m) goes (by means of a hose) to the chemical products tank by means of the servo- valve branching output (r), or whether it pours into the ground by means of the venting valve output (s).

The venting orifice (d) allows the operator to connect an external pump in order to make water circulate through the distribution system which is connected to the controlled fluid output (q) in order to clean this distribution system. The nonreturn valve (I) prevents liquid from escaping from the venting orifice (d).

The pressure relief valve (o) opens in order to protect the machine if the pressure is very high. In these cases, the liquid is discharged from the system via the pressure relief valve output (p). This output can be connected by means of a hose to the chemical products tank.

Thus in this embodiment the invention comprises a pumping and control system for application of water and/or liquid products (for example, but not limited to, fertilisers/ inoculants/fungicides/ insecticides) on agricultural ground. For this purpose, it has a pump driven by a hydraulic motor which circulates both the water and the products to be applied. The system has the requisite inputs for water and chemical products, which the operator can select so that the said fluid is supplied to the distribution system. The invention makes it possible to apply mainly water (and also liquid fertilisers) directly in the sowing line. The water/liquid product is applied directly into the furrow by means of hoses which abut the (double disc) blades of the sower (see Figure 4). Thus, when the blades perforate the ground and deposit the seed in the furrow, the device applies the liquid in the exact place where the seed was deposited, which provides the necessary and optimum humidity around the seed so as to permit optimum germination of the latter. Thus, the dynamics of the device allow it to be coupled to any seed drill, irrespective of the model or make, since the main function is fulfilled (in addition to the components of the device itself) by using the elements which are present in any of these seed drills. That it, the device is "retrofittable". The sowing body is designed for a furrow opener (blade which opens up the ground in order to facilitate the entry of the V-disc). The V-disc acts as a protector and double wall where the tube which deposits the seed is located. To the latter there is coupled the hose for discharge of liquid (for this purpose the appropriate hoses of the distribution system are put into place), from where the seed is deposited in the furrow (exactly where the liquid which moistens and provides humidity all around the seed is applied). Then the "beaver tail" or the seed pressing wheel (not recommended) compacts the humidity of the sowing line and then the closing wheels seal the furrow, keeping the humidity intact and available. Its duration depends on the coverage (very important) temperature of the ground and the time of the year. It should be pointed out that the greater the volume of water, the more days the humidity will last in the ground at a depth of 4 to 8 cm, protected by being covered by the soil. The seed can be sown at 4 to 6 cm and the moisture will create a circumference of 25 cm3 around the seed, making it geminate and seek underground moisture.

In turn the distribution system for water and liquid fertilisers is controlled by the computerised control system (see Figure 3) which is responsible for regulating the pressure and flow of liquid supplied by means of its corresponding valves, thus allowing the operator to modify these parameters from the computerised control console (which is separate from the module). The front of the main module includes a digital display which shows the speed of the pump, and a measurer which shows the pressure and the possibility of carrying out venting of the pump. The computer can count with a GPS speed sensor, can measure the hectares sown and the distance (e.g. kilometres) that has been done, and can be extracted with pen-drive, achieving worked surface.

In addition, it is possible to add an agitation tank which keeps the liquids correctly mixed. This is because the system has a return which mixes or acts as a beater for the liquids to be applied when the operator stops the functioning of the distribution system.

Since the system permits application of water or fertilising liquids directly in the sowing line in quantities of, say, 50 litres up to 3000 litres per hectare, there is generation of the supply of water necessary to achieve the effect of ploughing irrigation in the : a) 19,230 linear metres which exist in a hectare (with a distance of 52 cm between sowing furrows); b) 28,571 linear metres which exist in a hectare (with a distance of 35 cm between sowing furrows); c) 57,143 linear metres which exist in a hectare (with a distance of 17.5 cm between sowing furrows); d) 45,454 linear metres which exist in a hectare (with a distance of 22 cm between sowing furrows). For further details see the appended humidity calculation tables in Figures 5 and 6. By this means, the system fulfils the function of providing ploughing irrigation on the sowing line itself. Consequently, and as a direct result of the avoidance of humidity contingencies, the productivity of the ground is increased, since more days of sowing are possible and there is a greater percentage of growth of the seed: a) As liquid is applied in the sowing line, it is possible to optimise the sowing date, sow with moisture even when humidity is scarce, and extend the normal sowing period since the humidity which will be absorbed by the soil will compensate for days when there has been no recent rain; also, fertilisers and inoculating liquids can be applied in the sowing line; b) the system in question permits germination of 99% of the seeds implanted in the sowing line, because of the humidity which our machine provides in the sowing furrow.

While the embodiments described herein above include two inlets, for liquid products and water respectively, it will be understood that only one inlet is required in order for the invention to provide a liquid product to the furrow. The liquid product may be water, or another liquid, or water mixed with another liquid, for example premixed in a tank. Furthermore, in embodiments which do include two inlets, the selector valve, which allows an operator conveniently to select the liquid to be applied to the furrow, is optional. Referring to Figure 4, there is illustrated the internal composition of the dual disc system of a seed drill (which system is generally present in any seed drill), in which there can be seen the arrangement of the duct for application of water or liquid fertilisers which will be applied directly in the sowing line. Figure 5 shows a position of moisture 5 around a seed.

Referring to the humidity calculations shown in Figures 6 and 7, the correlative tables have been produced on the basis that a litre (1 It) represents a millimetre (1 mm) of water poured onto a square metre (1 m²), i.e. 1 mm of depth. The volume of irrigation is only the furrow line, which is equivalent to 1 .5 cm width for the line of all the furrows in the hectare. The unknown factor would be the depth (in mm) of irrigation with X quantity of litres. The volume of irrigation is shown in a water column as such and with the water column positioned on ground with 30% to 40% porosity (porosity is greater in sandy soils and lesser in clay soils). Figure 8 shows a table with a comparison between tanks with different volumes.

It will be understood that the invention has been described in relation to its preferred embodiments and may be modified in many different ways without departing from the scope of the invention as defined by the accompanying claims.

Claims

1 . A liquid supply unit for use with an agricultural machine to deliver a liquid to a furrow, the liquid supply unit comprising:

a liquid product inlet for receiving a source supply of liquid product;

a pump, arranged to draw the liquid product into the liquid product inlet; and

an outlet, arranged to expel the pumped liquid product to a liquid distribution element of the agricultural machine, the liquid distribution element being arranged to deliver the liquid product to the furrow.

2. A liquid supply unit according to claim 1 , including a water inlet for receiving a source supply of water, wherein the pump is arranged to draw one of the liquid product and the water into the respective inlet, and the outlet is arranged to expel the pumped liquid product or water to the liquid distribution element of the agricultural machine, the liquid distribution element being arranged to deliver the liquid product or water to the furrow.

3. A liquid supply unit according to claim 2, including a selector, for example a selector valve, for selecting between the liquid product inlet and the water inlet.

4. A liquid supply unit according to any one of claims 1 to 3, wherein the liquid product comprises a fertiliser, an inoculant, a fungicide, or an insecticide.

5. A liquid supply unit according to any one of claims 1 to 4, wherein the liquid product comprises water.

6. A liquid supply unit according to any one of claims 1 to 5, including a store, for example one or more tanks, for storing the source supply of liquid product.

7. A liquid supply unit according to any one of claims 1 to 6, wherein the pump comprises a positive displacement pump, for example a piston diaphragm pump.

8. A liquid supply unit according to any one of claims 1 to 7, including a motor, for example a hydraulic motor, configured to drive the pump.

9. A liquid supply unit according to claim 8, including a flow control unit, for example a hydraulic flow control unit, for controlling the flow rate of the liquid product, optionally at a constant speed.

10. A liquid supply unit according to claim 9, wherein the hydraulic motor and the hydraulic flow control unit are configured to connect to a hydraulic system or cardanic system of the agricultural machine.

1 1 . A liquid supply unit according to any one of claims 1 to 10, including a pump speed indicator, for example a digital pump speed indicator, for indicating the current speed of the pump.

12. A liquid supply unit according to any one of claims 1 to 1 1 , including a pressure sensor for indicating the pressure of the liquid product at the outlet.

13. A liquid supply unit according to any one of claims 1 to 12, including a flow measurer for determining the flow rate of the liquid product, for example the volumetric flow rate or the mass flow rate.

14. A liquid supply unit according to any one of claims 1 to 13, including an electro-hydraulic servo valve which is configured to vary the pressure of the pumped liquid product.

15. A liquid supply unit according to any one of claims 1 to 14, including a closure valve which is configured to open or close in order to permit or prevent expulsion of the liquid product from the outlet.

16. A liquid supply unit according to claim 14 or 15, including a controller for controlling respectively the electro-hydraulic servo valve and the closure valve.

17. A liquid supply unit according to claim 16, wherein the controller includes a console for use by an operator to vary the pressure, flow, and/or frequency of application of the liquid product.

18. A liquid supply unit according to any one of claims 1 to 17, including a venting/operating selector which is configured to direct the liquid product to the liquid product source supply, via a branch outlet of the electro-hydraulic servo valve, or to direct the liquid product to the ground, via a venting outlet.

19. A liquid supply unit according to any one of claims 1 to 18, including an agitation tap which is configured to provide a flow of the pumped liquid product to the source supply of liquid product in order to agitate the source supply of liquid product so as to keep the liquid product properly mixed.

20. A liquid supply unit according to any one of claims 1 to 19, including a venting orifice which is configured to connect to an external pump to circulate water through the distribution element of the agricultural machine, when connected to the outlet, in order to clean the distribution element.

21 . A liquid supply unit according to claim 20, including a non-return valve which is configured to prevent the water from escaping from the venting orifice.

22. A liquid supply unit according to any one of claims 1 to 21 , including a pressure relief valve which is configured to open to expel the pumped water or liquid product if the pressure thereof exceeds a predetermined value.

23. A liquid supply unit according to claim 22, including an element, for example a hose, which is configured to convey the expelled liquid product to the source supply of liquid product.

24. A liquid supply unit according to any one of claims 1 to 23, including a suction filter for filtering the liquid product before the liquid product reaches the pump.

25. A liquid supply unit according to any one of claims 1 to 24, including a line filter which is located downstream of the outlet and configured to connect to the distribution element, for example a manifold of the distribution element.

26. An agricultural machine, for example a sowing machine, comprising a liquid supply unit according to any one of claims 1 to 25.

27. An agricultural machine, for example a sowing machine, configured to deliver a liquid to a furrow and including a liquid supply unit, the liquid supply unit comprising:

a liquid product inlet for receiving a source supply of liquid product;

a pump, arranged to draw the liquid product into the liquid product inlet; and

28. A method of delivering a liquid to a furrow, comprising:

providing an agricultural machine, for example a sowing machine, configured to deliver a liquid to a furrow and including a liquid supply unit, the liquid supply unit comprising:

a liquid product inlet for receiving a source supply of liquid product;

a pump, arranged to draw the liquid product into the liquid product inlet; and

an outlet, arranged to expel the pumped liquid product to a liquid distribution element of the agricultural machine;

pumping a liquid product through the liquid supply unit to the distribution element; and

delivering the liquid product to the furrow as seeds are placed in the furrow.