GB2304060A - Cartridges for agricultural sprays - Google Patents

Abstract

A cartridge 18 containing an additive to be added to a diluent (eg water) for spraying crops is retained in a holder 20. The contents of the cartridge are expelled into the diluent by means of piston 22 driven by motor 24. Different proportions of additive in the diluent are provided by using cartridges of various sizes. The holder 20 is adapted to accept a range of these sizes, for example, by means of the retaining springs 28. This obviates the need for controlling the speed of the motor and allows it to be driven at one rate.

Description

LIQUID DISPENSING METHOD AND APPARATUS This invention relates to a method and apparatus for liquid dispensing, particularly for use in agricultural or horticultural boom-type spraying apparatus comprising multiple spray nozzles located at intervals along the length of such boom, to supply a liquid spray medium to such nozzles. The invention may find application otherwise than strictly in relation to such spraying apparatus.

The liquid spray medium supplied to the spray nozzles of agricultural and horticultural sprayers usually comprises a mixture of a liquid diluent, namely water, and a liquid concentrate which is adapted to the spraying purpose in hand.

Examples include herbicides, insecticides, nematicides etc.

It is a well known fact that agricultural and horticultural spraying concentrates are hazardous to health and that steps need to be taken to minimise exposure of personnel to such materials, particularly in their concentrated form. Accordingly, the conventional approach to the production of a liquid spray medium by means of a manual process of addition of the concentrate to water in the main spray tank is now seen to be unacceptably hazardous.

There has been proposed in W092/11759 (Prolion) (published 23 July 1992) a spraying device having a system whereby the water diluent is mixed with the liquid concentrate in a dynamic manner during the course of the passage of the water from the main tank to the spray nozzles.

Such an arrangement substantially reduces the risk to personnel arising from the use of the concentrated spray medium and, in this respect, the disclosure in the above specification is an improvement in relation to the conventional technique of producing spray medium as discussed above.

Nevertheless, there are significant shortcomings in the disclosure in the above WO specification in relation to the important feature of simplicity of construction and usage, and related matters.

As disclosed in Fig 3 of the above WO specification there is provided a cartridge or container for the liquid spray concentrate, and this container is piston-actuated and provided with a needle valve member to open and close it.

There are also disclosed elsewhere in the WO specification various valve arrangements for alternative embodiments of the cartridge or container.

In order to install the cartridge of the Fig 3 embodiment of the WO specification it is necessary to screw-fit the cartridge to an associated threaded collar and to insert a valve member into the open end aperture in the cartridge.

Accordingly, the cartridge necessarily has an open end aperture, at least temporarily prior to its fitment to the remainder of the apparatus, which represents a significant health hazard.

Moreover, the embodiments in the above WO specification are all relatively complex and do not permit the safe removal of the cartridge from the apparatus before it is emptied.

Additionally, the actuation mechanism for the dispensing of the concentrate from the cartridges requires multi-speed actuation of the pumping system by the associated motor and this leads to significant technical complication and cost due to the well known technical difficulties of providing a drive motor which has a range of very well defined operating speeds which are maintained substantially regardless of load.

Systems exist for the provision of such performance but they tend to be expensive and in any case require to be programmed by the user, which leads to a further lack of simplicity of operation.

One aspect of the difficulties of providing reliable and accurate motor speed control concerns the inter-related questions of motor temperature, voltage and speed. While it is a matter of well-established technology to control the output speed of an electric motor by means of well-recognised motor control systems, nevertheless, the limitations of these arise from their use of voltage control to control speed.

While, under ideal conditions such a system can reliably and accurately control motor speed, in practice under normal working conditions the result is less than satisfactory. Due to the corresponding increase in motor current at lower motor speeds and the consequential heating effect on the motor, which is proportional to the square of the current, the net result is that the motor temperature rises significantly and this in itself has a direct effect upon motor speed, whereby a further compensation effect needs to be introduced in order to maintain accurately the motor output speed.

The complications inherent in introducing such a second level of motor speed control are substantial and effectively quite unacceptable for practical purposes. Hence the need for a radically different approach is seen to be paramount. A system in accordance with the present invention which allows varying dispensing speed to be achieved, while running the motor at its optimum speed is seen to be extremely desirable.

We have identified a requirement for significant simplification of the systems provided for admixture of liquid concentrate with liquid diluent in spraying systems whereby manufacture and/or use of the system is/are significantly simplified, or improvements generally therein are provided.

According to the invention there is provided liquid dispensing apparatus and a corresponding method as defined in the independent claims of the accompanying claims. There is also hereby incorporated into the description portion of this text the entire text of the claims filed herewith.

In the described embodiments of the invention the receptor apparatus for the concentrate cartridges is adapted to receive and connect two cartridges of differing crosssectional area. In this way, the advantage is provided that the concentrate supply apparatus can dispense the concentrate at two or more corresponding rates without changing the rate or speed of the drive to the dispensing mechanism. In other words, the drive for the concentrate dispensing mechanism can operate at a constant speed. This has significant technical advantages since electric motors for the purpose can be readily constructed to provide a reliable and well regulated constant speed at the chosen optimum speed of the motor in question.When such a motor is required to operate at significantly different speeds, although such can be achieved by means of motor regulation systems, these are complex and not always adequately accurate in performance.

In the embodiment, there is provided yieldable support means to receive the cartridges of different cross sectional areas, whereby such cartridges can be loaded quickly and in a simple manner without the need for any adjustment or adaptation of the mechanism.

Also in the embodiments, there is provided a system in which two or more cartridges of concentrate are provided to contain different liquid concentrates which require to be dispensed at differing rates with respect to a given rate of dispensing of the water diluent. The cartridges have differing cross-sectional sizes which differ in area to an extent corresponding to the difference in the required dispensing rates. Thus, in use, a farmer can be provided with a cartridge of concentrate which is of such a cross sectional area as to correspond exactly to the required dilution ratio of the material in question. Accordingly, the user merely has to install the cartridge by a simple push-fit action which causes automatic connection of the cartridge to the hydraulic systems of the sprayer. The cartridge is then connected to the actuation mechanism, the latter being driven at the same speed as is used for all other cartridges, but the required dispensing rate for the concentrate is achieved due to the accurately defined cross sectional area of the cartridge. The total volume of the cartridge (and thus the area of crop or field which can be covered) may be varied at will by varying its axial length.

The push-fit facility provided for the cartridge whereby it is connected to the hydraulic systems of the sprayer simplifies its installation, and indeed its removal.

Moreover, there is provided liquid sealing means which seals the cartridge not only prior to such fitting, but after removal therefrom. It often happens of course that a given period of spraying in a field does not conveniently consume the exact amount of concentrate provided in a given cartridge, and therefore it is desirable for the user to be able to remove the cartridge so that, if so desired, a different cartridge can be used next time. For this purpose, the liquid sealing means of the cartridge comprises a penetrable diaphragm or closure which is adapted to be penetrated by a hollow needle in the cartridge receptor apparatus, so that the needle can remove concentrate. Moreover, the diaphragm or closure is adapted to re-seal after removable of the needle.

This can be provided by means of a suitable resilient elastomer as the material of the penetrable diaphragm.

Alternatively, a valve member may be provided which is biased inwardly to a closed position and is adapted to be opened by pressure generated within the cartridge by the piston.

A self-aligning thrust connector is provided for the pistons of the cartridges to simplify their connection to their actuation motor.

A further aspect of the invention concerns the question of dealing with the residue of concentrate which remains in a concentrate cartridge or other container after use of same, when the container is substantially empty.

In the case of concentrate containers which have hitherto been used in a conventional way for manual admixture of the contents with water in the main spray tank of a sprayer, there is a need to dispose of the concentrate container after the mixing operation. It has been found that the cost of such disposal makes a very substantial addition to the cost of the spraying operation.

Much the sane question arises in the case of spent cartridge of spray concentrate which have been used in spraying apparatus according to the present invention. These require either to be disposed of or else to be refilled. Even in the case where they are to be refilled there are cost implications in the transportation of the spent cartridges from the farm to the refilling station arising from the presence of the relatively small amounts of chemical concentrate still present in the spent cartridges.

An object of the present invention is to provide a method and apparatus for eliminating or reducing these problems.

according to the invention there is provided a method and apparatus as defined in claims 17 to 24 of the accompanying claims.

In the embodiments of this aspect of the invention there is provided a cartridge or other container for spray concentrate wherein the container has located therein a releasable supply of a neutralising of flushing medium for the concentrate. In one embodiment, the supply is in the form of a frangible container such as a sachet which is arranged to be broken or perforated at the end of the cycle of use of the cartridge so as to release the neutralising or flushing medium. Thus, in this embodiment the neutralising medium is automatically released. This can be achieved by means of the movement of the piston within the cartridge, the arrangement being such that the movement of the piston brings the frangible container into engagement with a piercing or perforating structure.Of course, an inverse arrangement could be provided in which the container of neutralising medium would be provided within the cartridge at the discharge end thereof for perforation or rupture by the piston at its stroke end, instead of being mounted on the piston itself for movement therewith.

It is also envisaged that for certain applications the supply of neutralising medium might be provided at an exterior location with respect to the concentrate container, for example mounted at its exterior surface and connected to its interior so that the neutralising medium can be delivered at the relevant time.

By providing neutralising or flushing means associated with a chemical concentrate container, together with the means for effecting such neutralisation or flushing, the container is provided in a state whereby, when its spray concentrate has been expended it is automatically or readily changed in state to a chemically neutral condition so that the container can be handled and processed without the need for toxicity precautions. Thus, in this way, a chemical concentrate container is rendered chemically neutral and easily handleable, without the cost implications which have hitherto been associated with it. Moreover, such provision can be readily made at the time of initial manufacture of the cartridge.In the case where the supply of neutralising medium is provided within the cartridge, this has no effect on the space requirements of the cartridge, and it can be handled after use in a straightforward manner and disposed of without substantial cost.

With regard to the neutralising medium, this is chosen in accordance with the nature of the spray concentrate in question. Usually, the neutralising medium will be a chemical reactant or reagent which reacts with the concentrate residue to provide an inactive or inert or neutral product which is less harmful or non-harmful to life. Thus, for each spray concentrate, the chemical nature of the principal active ingredients will enable the development of a corresponding neutralising or antidoting medium. This latter may not always be one particular chemical compound or reagent for any given spray concentrate since the options for the production of a relatively inert or neutral reaction product may be various in any given case.At the simplest level, it might be sufficient in some cases merely to adjust the pH of the concentrate residue by addition of a base or alkali or acid, according to the circumstances of the case.

In some cases it may be sufficient to provide, instead of a neutralising or antidoting medium, simply a flushing medium which is released at the time when the cartridge or container is exhausted and simply dilutes or flushes out the residue of concentrate into the supply of diluent from the main tank and can be discharged through the spray nozzles.

Where a flushing function is required, this may be provided by means of a supply of flushing medium in a container within the cartridge or other container, for release in the same manner as a neutralising or antidoting medium.

The flushing medium might be no more than a supply of water sufficient to dilute the concentrate residue enough to render it relatively harmless and inactive. The flushing medium could even be a gas. Alternatively, there could be provided an additional connector on the cartridge for coupling to the supply of diluent and arranged to deliver a supply of diluent to the interior of the cartridge after the latter has been exhausted. In the illustrated embodiment, this arrangement is provided by means of an inlet through the piston which serves to discharge the spray concentrate.

Embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which Fig 1 shows a side elevation view of a cartridge in position in liquid dispensing apparatus according to the invention and the cartridge being shown engaged with receptor apparatus for the cartridge and a drive for the piston of the cartridge; Fig lA shows an end view of the cartridge and its associated yieldable support means; Fig 2 shows one portion of Fig 1 on a larger scale; Figs 3 and 4 show two cartridge assemblies with alternative sealing arrangements; Figs 5 and 6 show the sealing arrangements of Figs 4 and 3 respectively on a larger scale; and Figs 7 and 8 show modifications of the embodiment of Fig 2 in which provision is made for the use of a neutralising or flushing medium to deal with the residue of spray concentrate after discharge of the cartridge.

The apparatus described herein is intended for use in agricultural or horticultural boom-type spraying apparatus, for example such apparatus as described in our prior specifications EP - A - 05 39 360 and/or EP - A - 06 00 919.

We hereby incorporate in the present application the entire disclosure of these prior specifications as part of the disclosure of the present application. It is to be understood that the sprayer comprises a main water tank and an associated pump for delivery of same to the spray nozzles. The dispensing apparatus described below is located downstream of the main tank and its pump, and upstream of the spray nozzles of the boom.

As shown in Fig 1, liquid dispensing apparatus 10 connected as described above, to agricultural or horticultural boom type spraying apparatus comprising multiple spray nozzles located at intervals along the length of the boom, comprises diluent supply apparatus in the form of a conduit 14 through which water from the pump and main tank is delivered.

Apparatus 10 further comprises concentrate supply apparatus 16 adapted to supply a flow of liquid concentrate to the diluent supply.

Concentrate supply apparatus 16 comprises a cartridge 18 and receptor apparatus 20 to receive the cartridge and to interconnect it with the diluent supply 12.

Cartridge 18 comprises a piston 22 and a drive 24 therefor.

Receptor 20 is adapted to receive and connect to cartridges 18 of differing cross-sectional areas so that the apparatus 10 can dispense concentrate at two or more corresponding rates without changing the rate or speed of drive 24.

Receptor apparatus 20 is adapted to receive the cartridges of differing cross-sectional area by means of yieldable support means 26 comprising curved support elements 28 of spring steel.

Drive 24 has only one speed of operation for normal dispensing of concentrate. Moreover, cartridge 18 is a pushfit into receptor apparatus 20 and has liquid sealing means 30 shown in more detail in Figs 3 and 4 and 5.

In the embodiment of Figs 4 and 6, the liquid sealing means 30 is in the form of a penetrable diaphragm or seal 32 adapted to be penetrated by a hollow needle (not shown) of receptor 20 for removal of concentrate, and which is likewise adapted to re-seal after removal of the needle. The diaphragm or seal 32 is of a resilient polymer such as natural rubber which readily re-seals.

In the embodiment of Figs 3 and 5, the liquid sealing means comprises a valve member 34 which is resilient biased inwardly with respect to cartridge 18 by a coiled spring 36 to a closed position in which a valve head 38 seats on a complementarily-profiled seat 40 formed in the neck portion 42 of cartridge 18. Pressure generated within the cartridge by piston 22 in use is able to open the valve provided by valve member 34 and spring 36.

As shown in Fig 1, drive 24 for piston 22 is delivered through a thrust member 44 having a self-aligning thrust connector 46 comprising complementary male and female conical formations 48 formed in piston 22 and thrust member 44.

Reverting to Fig 1, it will be noted that receptor apparatus 20 further comprises an outer housing 50 in which the cartridge 18 is received and which provides a mounting for the curved support elements 28. Housing 50 receives a casing 52 extending from drive 24 for thrust member 44.

As shown in Fig 2 in more detail, conduit 14 supplies water to a mixing chamber 54 where an impeller 56 driven by a motor 58 mixes concentrate with water and the resulting liquid spray medium is delivered through an outlet conduit 60.

It will be noted that receptor apparatus 20 further comprises a nose portion 62 having a tapering form and serving to guide the corresponding nose portion 64 of cartridge 18 during manual loading of the cartridge between the curved support elements 28.

Drive 24 comprises an electric motor and transmission means for actuating thrust member 44. Such mechanisms are known in themselves and no further description is deemed necessary.

In use, cartridge 18 is manually loaded by simple insertion between the curved support elements 28 and engagement with nose 62 of receptor apparatus 20 until positioned as shown in Figs 1 and 2. Drive 24 including thrust member 44 is offered up to piston 22 and thereby connected thereto, whereupon the apparatus is ready for operation. Removal of a partly or fully exhausted cartridge is performed by a reverse sequence of operations. The rate of dispensing of concentrate is determined by the cross sectional area of cartridge 18 in association with the fixed rate of extension of thrust member 44.

Cartridge 18 could be loaded radially instead of axially to avoid the need to re-position thrust member 44.

In the embodiment of Fig 7, provision is made for dealing with the residue of spray concentrate after discharge of the main body of concentrate. Otherwise, this embodiment is constructed and arranged substantially as described above in relation to Fig 2. Therefore, only structure and operations differing from that of Fig 2 will be described.

As shown in Fig 7 cartridge 70 has an outlet connector 72, as described previously, adapted to be connected to the supply of diluent, for admixture of the spray concentrate therewith.

Cartridge 70 is provided with supply apparatus 74 for a neutralising or flushing fluid 76, whereby the fluid can be delivered to the interior of cartridge 70 to neutralise or dilute the spray concentrate residue after discharge.

In this embodiment, parts corresponding to the embodiment of Fig 2, which are relevant to this description of the operation of the embodiment of Fig 7 are numbered as in Fig Supply apparatus 74 comprises a frangible container 76 mounted on piston 22 for actuation by thrust member 44 and adapted to be cut or perforated or ruptured at the end of the stroke of piston 22 by engagement of container 78 with a cutting or perforating device 80 mounted in the conical discharge end of cartridge 70.

Thus, container 78 is installed when cartridge 70 is filled and is automatically cut or opened at the end of the stroke of piston 22 so as to release the fluid 76 to neutralise or dilute the residue of concentrate. Some at least of this can then be discharged by further advancement of piston 22.

In the embodiment of Fig 8 the supply apparatus for the neutralising or flushing fluid comprises connection apparatus 82 adapted to connect to an external supply of neutralising or cleaning or flushing fluid. Thus, piston 222 is in this case provided with a bore 84 having a connection tube 86 which is connected to the supply of neutralising or cleaning or flushing fluid.

A ball valve 88 in bore 84 prevents flow-back of concentrate and/or the cleaning/neutralising/flushing fluid during use.

In use,in this embodiment the supply through connection tube 86 of the relevant fluid is provided at the end of the stroke of piston 22 and may be signalled automatically by a proximity sensor or other means capable of sensing the end of the stroke of the piston, or a related function.

In the above embodiments, a remarkable degree of practicality is achieved in relation to the ability to accommodate differing rates of chemical concentrate dispensing.

For example, a ratio 200 : 1 can be readily provided in terms of accommodating one spray concentrate which requires a volume of 20 litres per hectare covered, and another concentrate which requires merely 100 millimetres per hectare. This very substantial difference in ratio can be achieved, for example, by means of cartridges having respective cross-sectional diameters in the region of 300 millimetres and 14 millimetres respectively.

Moreover, the provision of a motor having a controlled constant speed for drive purposes in relation to the cartridge is a relatively straightforward matter since the provision of regulation systems to take account of the variation in input voltage from the electrical supply system of an agricultural tractor hauling the sprayer in question, is a simple and relatively low-cost requirement. The step-down (torqueincreasing) drive transmission from the motor to the cartridge actuation system ensures that there is ample torque for the purpose of achieving constant linear actuation speed in the cartridge. Thus, for example, the motor drive ratio is of the order of 33 x 33 : 1 = 1089 : 1.

For attraction purposes there is provided a higher speed reverse drive for the motor. This can be achieved by means of a third brush in the motor itself. Alternative rapid rewind arrangements may be provided but in general there is usually sufficient time at this stage in the cycle of spraying operations for a complete rewind to be achieved using reversal of the motor.

In the above embodiments, the provision in Fig 7 of a conical formation on piston 22 represents merely one possible format for the frangible container 76 and it is expected that a concave piston formation is likely to produce beneficial results in relation to fluid flow within the cartridge internal volume.

In the cartridge of Fig 7, the outlet connection 72 may be a screw or other fitting adapted to be readily connected and disconnected from the main body of the cartridge itself, possibly using a special tool for opening purposes. This enables flushing of washing to be readily carried out a reprocessing site, followed by recharging.

The structure of the cartridge itself may be adapted for production by a blow-moulding technique based upon the use of a synthetic polymeric material for the cartridge body.

In a modification, not shown in the drawings, the arrangement is such that the concentrate delivery from the cartridge is delivered, not into the conduit leading from the main spray tank to the spray nozzles, but into the tank itself. As a result, the cartridge can be arranged to dispense its entire contents into the tank, and thus into a defined volume of water therein, so as to achieve a specified dilution rate. Mixing means may be provided in the tank. The delivery of concentrate from the cartridge to the tank is effected totally safely and without intervention on the part of the operator.

By virtue of this modification, the advantages of the cartridge system in terms of safety and accuracy are retained.

Moreover, in the same way that differing sizes of cartridge can be utilised in the previously described embodiments to achieve required dilution rates, so, in this embodiment a similar result is achieved by discharging the entire contents of a cartridge into a known volume of water in the tank.

Obviously, in the case where a larger amount of concentrate is required, a larger cartridge will be employed. Likewise, there is no particular need in this case for an accurately constant rate of discharge. In such a case, it can be arranged that the cartridge will be discharged relatively quickly. In some cases it might be possible to arrange matters so that the cartridge itself is calibrated and the operated might have a control system enabling him to discharge an observable volume or proportion of the liquid in the cartridge into the tank.

In a further modification, the invention is employed in apparatus other than the strictly conventional type of boom sprayer. For example, the apparatus could be used in spraying apparatus of the kind employed for irrigation purposes in which the apparatus is conencted to a delivery pipe or conduit for irrigation fluid and the invention provides the means for injecting liquid concentrate into the feed of irrigation fluid in the manner discussed above.

Accordingly, the term agricultural or horticultural boom type spraying apparatus as used herein is to be interpreted as including all kinds of irrigation apparatus likewise.

In a modification, the cartridge outlet is provided in the cartridge piston and dispensed liquid is derived directly from that outlet in the system. Before use, the cartridges are stored in an upright attitude so that any sludge developing within the cartridge moves away from, rather than towards the cartridge outlet. The cartridge may be provided with a flat standing surface or the like for this purpose.

A further modification envisages the provision of piston position monitoring means with remote sensing of same and electronic display of the instantaneous piston position in order to enable the operator to take account of same as spraying progresses.

In the case of spray boom treatment of weed-infested crop there is a requirement for some economical means for weed treatment as appropriate. As weed growth is often confined to particular regions in a crop, blanket treatment of the entire crop with an appropriate herbicide is wasteful and unacceptable environmentally. The invention permits appropriate steps to be taken to enable selective application of a herbicide. This can be achieved by the provision of at least one herbicide cartridge, additional to other liquid being sprayed, so that the herbicide can be injected into the liquid supplied. This feature in combination with a facility to control injection from the driver's position enables injection to commence a few seconds before a weed-infested region is reached.

Accordingly, the provision of one or more additional injectors containing appropriate herbicides together with associated control equipment enables selective application of same to relatively well-defined and confined regions of the crop.

Claims (28)

CLAIMS :

1 Liquid dispensing apparatus adapted for use in agricultural or horticultural boom type spraying apparatus comprising multiple spray nozzles located at intervals along the length of such boom, to supply a liquid spray medium to such nozzles, said medium comprising a mixture of a liquid diluent and a liquid concentrate, said apparatus comprising a) diluent supply apparatus adapted to supply a flow of said liquid diluent; b) concentrate supply apparatus adapted to supply a flow of said liquid concentrate; c) said concentrate supply apparatus comprising a cartridge or like container to contain said concentrate; d) said concentrate supply apparatus further comprising receptor apparatus for said cartridge and adapted to receive same and to interconnect same with said diluent supply apparatus for admixture of said concentrate to said diluent; and e) said concentrate supply apparatus comprising piston apparatus and a drive therefor to expel said concentrate from said cartridge to dispense same into said diluent; characterised by f) said receptor apparatus being adapted to receive and connect to cartridges of differing cross-sectional area whereby said concentrate supply apparatus can dispense said concentrate at two or more corresponding rates without changing the rate or speed of said drive.

2 Liquid dispensing apparatus adapted for use in agricultural or horticultural boom type spraying apparatus comprising multiple spray nozzles located at intervals along the length of such boom, to supply a liquid spray medium to such nozzles, said medium comprising a mixture of a liquid diluent and a liquid concentrate, said apparatus being characterised by being adapted to receive and connect to cartridges or containers of differing cross-sectional size whereby the concentrate can be dispensed at two or more corresponding rates without changing the rate or speed of the drive to the cartridges.

3 Liquid dispensing apparatus adapted for use in agricultural or horticultural boom type spraying apparatus comprising multiple spray nozzles located at intervals along the length of such boom, to supply a liquid spray medium to such nozzles, said medium comprising a mixture of a liquid diluent and a liquid concentrate.

4 Apparatus according to any one of claims 1 to 3 characterised by said receptor apparatus being adapted to receive said cartridges of said differing cross-sectional area by means of yieldable support means therefor.

5 Apparatus according to claim 4 characterised by said yieldable support means comprising spaced resilient support elements adapted to engage yieldingly the external surface of said cartridges at corresponding spaced intervals to provide support therefor at locations spaced lengthwise and/or circumferentially of said cartridges.

6 Apparatus according to claim 5 characterised by said yieldable support means comprising curved support elements of spring steel.

7 Apparatus according to any one of the preceding claims characterised by said drive for said piston apparatus having only one speed of operation for normal dispensing of said concentrate.

8 Apparatus according to claim 7 characterised by said liquid dispensing apparatus comprising at least two cartridges for said concentrate, said cartridges being adapted to contain different liquid concentrates which require to be dispensed at differing rates with respect to a given rate of dispensing said diluent, and said cartridges being of differing cross sectional sizes which differ in area to an extent corresponding to the difference in said required dispensing rates.

9 Apparatus according to any one of the preceding claims characterised by said cartridge being adapted to be received in said apparatus as a push-fit into said receptor apparatus and said cartridge having liquid sealing means adapted to seal said cartridge firstly prior to such fitting into said receptor and secondly after removal therefrom.

10 Apparatus according to claim 9 characterised by said liquid sealing means comprising a penetrable diaphragm or closure adapted firstly to be penetrated by a hollow needle of said receptor apparatus for removal of concentrate, and secondly to re-seal after removal of said needle.

11 Apparatus according to claim 9 characterised by said liquid sealing means comprising a valve member resilientlybiased inwardly with respect to said cartridge to its closed position and adapted to be opened by pressure generated within said cartridge by said concentrate supply apparatus.

12 Apparatus according to any one of the preceding claims characterised by said concentrate supply apparatus comprising said piston apparatus and said drive therefor, said drive therefor comprising a thrust member adapted to connect to said piston through a self-aligning thrust connector.

13 Liquid dispensing apparatus adapted for use in agricultural or horticultural boom type spraying apparatus comprising multiple spray nozzles located at intervals along the length of such boom, to supply a liquid spray medium to such nozzles, said medium comprising a mixture of a liquid diluent and a liquid concentrate, said apparatus comprising a) diluent supply apparatus adapted to supply a flow of said liquid diluent; b) concentrate supply apparatus adapted to supply a flow of said liquid concentrate; c) said concentrate supply apparatus comprising a cartridge or like container to contain said concentrate; characterised by d) said cartridge having liquid sealing means adapted to seal said cartridge firstly prior to fitting into said receptor and secondly after removal therefrom.

14 Apparatus according claim 13 characterised by said liquid sealing means comprising a penetrable diaphragm or closure adapted firstly to be penetrated by a hollow needle of said receptor apparatus for removal or concentrate, and secondly to re-seal after removal of said needle.

15 Apparatus according to claim 13 characterised by said liquid sealing means comprising a valve member resiliently biased inwardly with respect to said cartridge to its closed position and adapted to be opened by pressure generated within said cartridge by said concentrate supply apparatus.

16 Agricultural or horticultural spraying apparatus comprising liquid dispensing apparatus according to any one of the preceding claims.

17 A cartridge or other container to contain spray concentrate and adapted for use in agricultural or horticultural spraying apparatus, the container comprising : a) an outlet connector adapted to be connected to said agricultural or horticultural spraying apparatus for delivery of said concentrate for admixture with a diluent prior to spraying; characterised by b) supply apparatus for neutralising or flushing fluid adapted to be delivered to the interior of said container to neutralise or dilute the spray concentrate residue after discharge.

18 A cartridge or other container to contain spray concentrate characterised by supply apparatus for neutralising or flushing fluid adapted to neutralise or flush or dilute the spray concentrate residue after discharge.

19 Apparatus according to claim 18 or claim 19 characterised by said supply apparatus comprising an interior supply of said neutralising or flushing fluid located within said cartridge or container and separated from said spray concentrate and adapted to be released after discharge of said concentrate.

20 Apparatus according to claim 19 characterised by automatic means for release of said supply after said discharge.

21 Apparatus according to claim 20 characterised by said automatic means comprising opening apparatus adapted to open the separated supply of said neutralising or flushing fluid at the end of the stroke of a discharge piston within said cartridge or container.

22 Apparatus according to claim 17 or claim 18 characterised by said supply apparatus comprising connection apparatus adapted to connect an external supply of neutralising or flushing or cleaning fluid to the interior of said cartridge or other container.

23 Apparatus according to claim 22 characterised by said connection apparatus being provided in the form of a connector duct extending through a discharge piston provided within said cartridge or container.

24 Claim 24 agricultural or horticultural spraying apparatus comprising a cartridge or other container as defined in any one of the preceding claims.

25 Liquid dispensing apparatus according to any one of the preceding claims adapted for use in agricultural or horticultural spraying and/or irrigation apparatus.

26 Apparatus according to any one of the preceding claims characterised in that the arrangement is such that cartridges or containers of differing size (not necessarily just cross-sectional size) can be received whereby the concentrate therefrom can be dispensed into a defined volume of diluent so as to achieve a dilution corresponding to the respective volumes of the diluent and the cartridge contents.

27 A method of agricultural or horticultural boom-type spraying comprising providing apparatus as defined in claim 2 and changing the rate of dispensing of concentrate by changing from a cartridge or container of one cross-sectional size to another cross-sectional size.

28 Agricultural or horticultural boom-type spraying apparatus comprising multiple spray nozzles located at intervals along the length of a boom, and means to supply a liquid spray medium to such nozzles, and at least one cartridge or container adapted to deliver a liquid concentrate into said liquid spray medium, together with remote control means for said cartridge or container to enable same to be actuated and de-actuated according to the need to dispense said concentrate into said liquid spray medium, whereby spraying with said concentrate from said cartridge or container eg herbicide can be selectively controlled remotely, in use.