WO2013117918A1

WO2013117918A1 - Dispensing apparatus

Info

Publication number: WO2013117918A1
Application number: PCT/GB2013/050267
Authority: WO
Inventors: Stephen Tarrant
Original assignee: Stephen Tarrant
Priority date: 2012-02-07
Filing date: 2013-02-06
Publication date: 2013-08-15
Also published as: GB201202086D0; GB2499383A

Abstract

The present invention relates to a dispensing apparatus and, in particular, to an apparatus for dispensing a measured amount of a first concentrated fluid, e.g. a fertiliser solution, into a flowing fluid stream, e.g. water. A dispensing apparatus for dispensing a measured amount of a first fluid into a flow of a second fluid comprises a main fluid flow conduit through which, in use, the second fluid flows, drive means mounted at least partially in the conduit such that the flow of the second fluid acts on a portion of the drive means, a storage vessel for holding a volume of the first fluid, and pump means connected to and driven by the drive means, the pump means being arranged to dispense an amount of the first fluid from the storage vessel into the main fluid flow conduit, wherein the amount of the first fluid that is dispensed by the pump means in a given time is dependent on the flow rate of the second fluid acting on the drive means.

Description

Dispensing Apparatus

BACKGROUND a. Field of the Invention

The present invention relates to a dispensing apparatus and, in particular, to an apparatus for dispensing a measured amount of a first concentrated fluid, e.g. fertiliser, into a flowing fluid stream, e.g. water. b. Related Art

A variety of devices exist which permit a concentrated liquid such as a fertiliser to be added to a fluid stream such as water flowing through a hose. These devices are typically in the form of hose end feeders or in-line hose diluters that comprise a reservoir of concentrated fertiliser solution that is dispensed into the main fluid/water stream. Many of the prior art devices work by allowing a portion of the main fluid stream to enter the reservoir, to replace the concentrated liquid that is dispensed. However, the disadvantage of these systems is that the concentrated liquid in the reservoir becomes more dilute over time. As such, the amount of fertiliser actually delivered via the stream of water decreases over time, even though the device may be indicating that the dilution ratio is constant.

Other prior art devices allow a user to adjust the size of the outlet of the reservoir to change the amount of concentrated liquid that is delivered. However, these devices to not account for changes in water pressure that affect the volume of water flowing through the hose in a given time, and, as such, do not provide a constant level of dilution. !t is an object of the present invention to provide an improved dispensing apparatus that overcomes the above problems.

SUMMARY OF THE INVENTION

According to the invention there is provided a dispensing apparatus for dispensing a measured amount of a first fluid into a flow of a second fluid, the apparatus comprising:

a main fluid flow conduit through which, in use, the second fluid flows;

drive means mounted at least partially in the conduit such that the flow of the second fluid acts on a portion of the drive means;

a storage vessel for holding a volume of the first fluid; and

pump means connected to and driven by the drive means, the pump means being arranged to dispense an amount of the first fluid from the storage vessel into the main fluid flow conduit,

wherein the amount of the first fluid that is dispensed by the pump means in a given time is dependent on the flow rate of the second fluid acting on the drive means.

Also according to the invention there is provided a method of dispensing a first fluid into a flow of a second fluid, the method comprising the steps of:

providing a main fluid flow conduit through which, in use, the second fluid flows;

- mounting drive means at least partially in the conduit such that the flow of the second fluid acts on a portion of the drive means;

providing a storage vessel for holding a volume of the first fluid; and connecting pump means to the drive means such that the pump means is driven by the drive means, the pump means being arranged to dispense an amount of the first fluid from the storage vessel into the main fluid flow conduit, wherein the amount of the first fluid that is dispensed by the pump means in a given time is dependent on the flow rate of the second fluid acting on the drive means.

Typically the first fluid is a liquid, and the second fluid may also be a liquid. In preferred embodiments of the invention the first fluid is a liquid fertiliser solution and the second fluid is water. In other embodiments, the first fluid is a liquid detergent solution and the second fluid is water.

The pump means is arranged such that a part of the pump means is in fluid communication with the storage vessel and a part of the pump means is in fluid communication with the fluid flow conduit, such that the pump means controls the amount of the first fluid drawn from the storage vessel and dispensed into the fluid flow conduit when a second fluid flows through the main fluid flow conduit and acts on the drive means. Preferably the drive means comprises a wheel having a plurality of blades on which the flow of the second fluid acts to turn the wheel. In this way, the drive means harnesses a portion of the kinetic energy of the flowing second fluid and uses this to power the pump means. In certain embodiments it is preferable if the wheel is located fully within the main fluid flow conduit.

Preferably the pump means comprises a cylinder and a piston, and the drive means comprises a gear and crank to convert the rotational movement of the wheel into linear motion of the piston. In these embodiments, the pump means and drive means are typically arranged such that during a first half of a revolution of the wheel the piston moves in a first direction and during a second half of a revolution of the wheel the piston moves in a second direction, opposite to the first direction. The pump means may further comprise a first valve means located between the storage vessel and the cylinder and a second valve means located between the cylinder and the main fluid flow conduit, the valve means being arranged such that, in use, when the piston moves in the first direction the first valve means opens to permit fluid from the storage vessel to enter the cylinder and when the piston moves in the second direction the second valve means opens to permit fluid to flow out of the cylinder into the main fluid flow conduit. As such, in these embodiments of the invention an amount of the first fluid is dispensed into the fluid flow conduit during half of each revolution of the wheel. In other embodiments it may be desirable for the pump means to comprise two cylinders, in these embodiments, the drive means is preferably connected to the cylinders such that during a first half of a revolution of the wheel a first cylinder fills with the first fluid from the storage vessel and a second cylinder dispenses a volume of the first fluid into the main fluid flow conduit, and during a second half of a revolution of the wheel the first cylinder dispenses a volume of the first fluid into the main fluid flow conduit and a second cylinder fills with the first fluid from the storage vessel. As such, in these embodiments, the first fluid is continuously dispensed into the flow of the second fluid. In other preferred embodiments, the pump means comprises a gear pump. Preferably the gear pump is an external gear pump and a shaft of a first spur gear is connected to a shaft of the wheel. Typically, an inlet of the gear pump is in fluid communication with the storage vessel, and an outlet of the gear pump is in fluid communication with the fluid flow conduit.

In further preferred embodiments, the pump means may comprise a screw pump. The pump means may additionally comprise a gear pump, an inlet of the gear pump being in fluid communication with an outlet of the screw pump. Typically the main fluid flow conduit is a hose.

Preferably the main fluid flow conduit includes valve means to permit flow of the second fluid in only one direction along the conduit. This prevents an amount of the first fluid that is dispensed into the fluid flow conduit from contaminating a source of the second fluid which is connected to an inlet of the main fluid flow conduit. Preferably the apparatus further comprises agitation means located in the storage vessel for agitating a volume of the first fluid held in the vessel, The agitation means may be used to stir a first liquid solution, for example, to prevent a solute settling out of solution in the storage vessel. Preferably the agitation means is connected to the drive means, such that a separate power source is not required.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be further described, by way of example only and with reference to the accompanying drawings, in which:

Figure 1 is a cross-sectional view from the side of a first preferred embodiment of a dispensing apparatus according to the present invention;

Figure 2 is a cross-sectional view along the line i i— 11 of Figure 1 of part of the dispensing apparatus;

Figure 3 is a plan view from above of a second preferred embodiment of a dispensing apparatus according to the present invention;

Figure 4 is a cross-sectional view from the side of the dispensing apparatus of Figure 3; Figure 5 is plan view from the side of a third preferred embodiment of a dispensing apparatus according to the present invention;

Figure 6 is a plan view of a gear pump forming part of the dispensing apparatus of Figure 5;

Figure 7 is plan view from the side of a fourth preferred embodiment of a dispensing apparatus according to the present invention; and Figure 8 is plan view from the side of a fifth preferred embodiment of a dispensing apparatus according to the present invention.

DETAILED DESCRIPTION

Figures 1 to 8 show embodiments of a dispensing apparatus 1 , 101 , 201 , 301 , 401 according to preferred embodiments of the present invention.

The apparatus 1 , 101 , 201 , 301 , 401 is arranged to dispense a pre-determined quantity of a first fluid into a flow of a second fluid, depending on the flow rate of the second fluid. Typically the dispensing apparatus 1 , 101 , 201 , 301 , 401 is used to deliver a quantity of a first liquid into a flow of a second liquid. In particular, the apparatus 1 , 101 , 201 , 301 , 401 may be used to dispense a concentrated liquid, such as a fertiliser or cleaning soiution, into a flow of a bulk carrier liquid, such as water.

The dispensing apparatus 1 , 101 , 201 , 301 , 401 generally comprises a conduit or channel 2, 102, 202, 302, 402 along which the second fluid flows, a storage vessel 4, 104, 204, 304, 404 containing a volume of the first fluid to be dispensed, pump means 6, 06, 206, 306, 406 for transferring a fixed volume of the first fluid from the storage vessel into the channel, and drive means 8, 108, 208, 308, 408 arranged such that the drive means is powered by the flow of the second fluid through the channel and operates the pump means to dispense the first fluid.

The drive means and pump means are arranged such that a first pre-determined volume of the first fluid is dispensed when a second pre-determined volume of the second fluid flows past the drive means. For example, a dispensing apparatus according to the invention may be arranged to dispense 2 ml of a concentrated fertiliser solution (a first liquid) for every 1 litre of water (a second liquid) that flows through the conduit or channel. A first preferred embodiment of the dispensing apparatus 1 is shown in Figures 1 and 2. The apparatus 1 includes a main liquid flow channel 2 which comprises a section of pipe 10. At a first end 12 of the pipe 10 there is attachment means 14 to enable the pipe 10 to be connected to a source of liquid, !n this example the attachment means 14 comprises a standard fitting to enable connection to a tap (not shown). The pipe 10 additionally includes a one-way valve or non-return valve 18 that permits liquid, in this example water, to only flow in one direction through the pipe 10, as indicated by the arrows in Figure 2. A second end 18 of the pipe 10 may be adapted to be connected to a further length of pipe or hose (not shown), or alternatively may be integrally formed with a length of hose.

A water wheel 20, forming part of the drive means 8, is located in the channel 2. Because the diameter of the water wheel 20 is greater than the width of the pipe 10, part of the channel 2 is shaped to form a housing 22 that surrounds the water wheel 20, as shown most clearly in Figure 2. Although the water wheel 20 has been shown as being horizontal, that is with a shaft 24 of the water wheel 20 being positioned vertically, the water wheel 20 may, alternatively, be vertical or may be positioned in any other suitable orientation with respect to the flow of liquid through the channel 2, as will be appreciated by a person skilled in the art.

The water wheel 20 includes a central shaft 24 and a plurality of blades 26 extending radially outwards from the shaft 24. Preferably the blades 26 are spaced equidistantly around the shaft 24 so that there is a fixed volume of space between any two adjacent blades 26. The number of blades 26 may be tailored to maximise the efficiency of the system as is known by a person of skill in the art. Typically the number of blades 26 will be adjusted based on various factors such as the cross-sectional area of the pipe 10 and the average flow rate of water along the channel 2.

At least a part of one blade 26 is located in the flow path of the water in the channel 2 at any given time. As water flows along the channel 2, the pressure of the water acting on the blades 26 of the water wheel 20 causes the water wheel to turn, which drives the pump means 6 as described below. In addition, the length of the blades 26 and, therefore, the overall diameter of the water wheel 20, determines the volume of water that flows past the water wheel 20 in one revolution of the wheel 20. The size of the water wheel 20 can, therefore, be chosen so that, for example, 1 litre of water flows past the water wheel 20 during each revolution.

An end 28 of the shaft 24 forms the central drive shaft of a gear 30, which, in turn, engages with or meshes with one or more additional gears to form a transmission. A crank rod 32 is connected at a first end 34 to the final gear in the transmission and is connected at its second end 36 to the pump means 6. In alternative embodiments, the crank rod 32 may be connected, at a first end 34, to a connecting rod extending between the gear 30 and the crank 32.

In this way, rotation of the water wheel 20 due to the flow of water through the channel 2 drives the rotation of one or more gears. The crank rod 32 then converts this rotational movement to a linear movement to actuate the pump means 6. A series of gears in a transmission may be used to vary both the number of strokes made by the crank rod 32 per revolution of the water wheel 20, and the length of each stroke. The pump means 6 comprises a single cylinder 38 and piston 40. The crank rod 32 is connected, at its second end 36, to a first end 42 of the piston 40 so that movement of the crank rod 32 causes reciprocating movement of the piston 40 within the cylinder 38. An inlet 44 of the cylinder 38 is in fluid communication with the storage vessel or tank 4 that contains the concentrated liquid to be dispensed, which in this example is fertiliser concentrate. A non-return valve 46 is located in the inlet 44 so that !iquid cannot flow back into the storage tank 4 from the cylinder 38. An outlet 48 of the cylinder 38 is in fluid communication with the channel 2, downstream of the water wheel 20. A one-way valve 50 is located in the outlet 48 so that liquid is only able to flow out of the cylinder 38 into the channel 2. In preferred embodiments the valves 46, 50 are ball valves.

The gear 30 and crank rod 32 are arranged such that the piston 40 makes two strokes for every one complete revolution of the water wheel 20. in this way, during a first half of a revolution of the water wheel 20, the piston 40 is drawn out of the cylinder 38, the valve 50 in the outlet 48 is dosed, the valve 46 in the inlet 44 opens and liquid flows from the storage tank 4 into the cylinder 38. During the second half of a revolution of the water wheel 20, the piston 40 is pushed into the cylinder 38, the valve 46 in the inlet 44 is closed, the valve 50 in the outlet opens and liquid is forced out of the cylinder 38 into the channel 2 and, therefore, into the flow of water.

The volume of the cylinder 38 can be chosen so that a required volume of concentrate liquid is dispensed for each revolution of the water wheel 20. As explained above, the water wheel 20 can also be chosen so that a fixed volume of water flows past the wheel for a single revolution. In this way, the dispensing apparatus can be used to accurately and consistently dispense a required volume of concentrate into a given volume of water.

The ratio of concentrate to water will not vary due to changes in water pressure because the water pressure varies in proportion to the flow rate, i.e. as the water pressure increases, the flow rate increases, and the dispensing of the concentrate is directly linked to the flow of the water turning the water wheel 20.

Figures 3 and 4 illustrate a second preferred embodiment of the dispensing apparatus 101. This embodiment includes many of the same features and components of the previous embodiment, and like features have been indicated by reference numerals incremented by 100. ln this embodiment the drive means 108 are the same as the drive means 8 of the previous embodiment. The shaft 124 of the water wheel 120 drives a first gear 130 which engages with a second gear 131 . The crank rod 132 is connected to the second gear 131 to actuate the pump means 06.

The pump means 106 comprises two cylinders 138, 139 both in fluid communication with a single storage tank 104. The crank rod 132 is connected, via a connecting arm 152, to two pistons 140, 141 , each one being associated with a respective cylinder 138, 139. The cylinders 138, 139 and pistons 140, 141 are oriented in opposing directions, such that as one piston 140 is pushed into a first cylinder 138, the other piston 141 is drawn out of the second cylinder 139. In this example, the two pistons 140, 141 are integrally formed such that there is a single piston rod 154 having two heads 156 at opposing ends, most clearly shown in Figure s.

The inlet 144, 145 of each of the cylinders 138, 139 is in fluid communication with the storage tank 104 and the outlet 148, 149 of each of the cylinders 138, 139 is in fluid communication with the channel 02. As previously described, each of the inlets 144, 145 and outlets 148, 149 includes a valve 146, 147, 150, 151 to permit flow of the concentrate liquid in only one direction.

The gears 130, 131 and crank rod 132 are again arranged such that each of the pistons 140, 141 makes two strokes for every one complete revolution of the water wheel 120. in this way, during a first half of a revolution of the water wheel 120, the piston 140 is drawn out of the cylinder 138, the valve 150 in the outlet 148 is closed, the valve 146 in the inlet 144 opens and liquid flows from the storage tank 104 into the cylinder 138. At the same time, the other piston 141 is pushed into its cylinder 139, the valve 147 in the inlet 145 is closed, the valve 151 in the outlet 149 opens and liquid is forced out of the cylinder 139 into the channel 102. During the second half of a revolution of the water wheel 120, the piston 140 is pushed into the cylinder 138, the valve 146 in the inlet 144 is closed, the valve 150 in the outlet 148 opens and liquid is forced out of the cylinder 138 into the channel 2, At the same time, the piston 141 is drawn out of the cylinder 139, the valve 151 in the outlet 149 is closed, the valve 147 in the inlet 145 opens and liquid flows from the storage tank 104 into the cylinder 139.

Arranging two cylinders 138, 139 in this way means that concentrate liquid is constantly injected or dispensed into the water stream, rather than concentrate liquid only being injected during half of each revolution of the water wheel.

In order to dispense the same volume of concentrate liquid for a given volume of water flowing past the water wheel 120 as in the previous embodiment, the cylinders 138, 139 may be designed to each have half the volume of the single cylinder 38 of the previous embodiment. Alternatively, in other embodiments, the volume of each of the two cylinders 138, 139 may be the same as the volume of the single cylinder 38 so that twice the volume of concentrate liquid can be dispensed for each revolution of the water wheel 120.

Figures 5 and 6 show a further alternative embodiment of a dispensing apparatus 201 according to the present invention. In this embodiment, the drive means 208 comprises a water wheel 220 located in the channel 202. The shaft 224 of the water wheel 220 is connected directly to the pump means 206, so that there are no gears or crank rod.

The pump means 206 comprises a gear pump 254 as shown most clearly in Figure 6. The gear pump 254 is an external gear pump and includes two spur gears 256, 257 arranged in a housing 258 such that the teeth 260, 261 of the spur gears 256, 257 mesh together in a central region of the gear pump 254, as is known in the art. An end portion 262 of the shaft 224 of the water wheel 220 forms the drive shaft of one of the spur gears 256 in the gear pump 254, such that rotation of this gear 256 is driven directly by rotation of the water wheel 220. Rotation of the second spur gear 257 is driven by the first spur gear 356 due to the engagement of their respective teeth 260, 261 , so that both gears 256, 257 rotate at the same speed but in opposite directions.

An inlet 284 of the gear pump 254 is in fluid communication with an inlet tube 266 that extends into the storage tank 204. An outlet 268 of the gear pump 254 is in fluid communication with the channel 202, and in this example is connected to the channel 202 downstream of the water wheel 220 by means of an outlet tube 270.

As the water wheel 220 rotates due to a flow of water along the channel 202, the spur gears 256, 257 of the gear pump 254 are driven to rotate in the directions indicated by the arrows in Figure 6. This causes concentrate liquid to be drawn from the storage tank 204 up through the inlet tube 268 and the inlet 284 of the gear pump 254. The concentrate liquid in then forced, due to the rotation of the spur gears 256, 257 around the outside of the gears 256, 257, between the gear teeth 260, 261 and an internal surface 272 of the housing 258, as indicated by the arrow in Figure 6. Meshing of the gears 258, 257 on the outlet side of the gear pump 254 then forces the concentrate liquid out of the outlet 268 of the pump 254, along the outlet tube 270 and into the channel 202.

The size of the gear pump 254 can be chosen to deliver a required volume of concentrate liquid per revolution of the water wheel 220, and because the gear pump 254 is driven directly by rotation of the water wheel 220, a desired ratio of concentrate liquid to water can be achieved.

Advantages of this pump means 208 is that it is able to deliver a wider range of liquid types, including higher viscosity substances. In addition, the gear pump 254 delivers concentrate liquid continuously into the water stream while the water wheel 220 is rotating.

This embodiment of the dispensing apparatus 201 also includes a bypass valve 274 located in the outlet tube 270 of the pump means 208. In a first position, the bypass valve 274 permits concentrate liquid from the outlet 268 of the gear pump 254 to flow through the outlet tube 270 and into the channel 202. In a second position, the bypass valve 274 prevents a flow of concentrate liquid along the outlet tube 270, and the concentrate liquid from the outlet 288 of the gear pump 254 is, instead, returned to the storage tank 204. The bypass valve 274 can, therefore, be used to stop concentrate liquid being delivered into the water flow, if a user requires pure water, without having to disengage the drive means 208 or the pump means 206, or disconnect the whole dispensing apparatus 201 .

Figure 7 shows a further preferred embodiment of a dispensing apparatus 301 according to the present invention, As in the previous embodiment, the drive means 308 comprises a water wheel 320 located in the channel 302. The shaft 324 of the water wheel 320 is connected directly to the pump means 306, so that there are no gears or crank rod.

The pump means 308 comprises a screw pump, or Archimedes' screw, 376, the shaft 378 of the screw 378 being integrally formed with the shaft 324 of the water wheel 320. The screw pump 376 further comprises a helical blade 380, extending around and along the length of the shaft 378, and a tubular housing 382 surrounding the helical blade 380. The screw pump 378 extends into the storage tank 304 such that a lower, open end 384 of the tubular housing 382, forming an inlet, is located near the bottom of the storage tank 304 and will be submerged when the storage tank 304 is filled with concentrate liquid.

As the water wheel 320 rotates due to a flow of water along the channel 302, the screw 376 turns and concentrate liquid is drawn up from the storage tank 304 through the tubular housing 382 by the helical blade 380, as is known in the art. An outlet 388 of the screw pump 376 is located at an upper end 388 of the tubular housing 382. The outlet 386 is in fluid communication with the channel 302, and in this example is connected to the channel 302 downstream of the water wheel 320 by means of an outlet tube 370. This example of the dispensing apparatus 301 also includes a bypass valve 374 located in the outlet tube 370 of the pump means 306 for diverting the concentrate liquid back into the storage tank 304, as described in relation to the previous embodiment.

The dispensing apparatus 301 further includes agitating means 390 to stir and mix the concentrate liquid within the storage tank 304. The agitating means 390 comprises a pair of blades or paddles 392 extending radially outwards from the free end 394 of the shaft 378 of the screw 376. As the water wheel 320 rotates, the shaft 378 rotates, which in turn causes the paddles 392 to rotate. In this way, the concentrate liquid in the storage tank 304 is continuously stirred during operation of the dispensing apparatus 301 . This stirring can, for example, prevent any solids settling out of the concentrate liquid.

Although in this embodiment the agitating means 390 is in the form of a pair of paddies 392 driven directly by the rotation of the water wheel 320, in other embodiments the agitation means 390 may be of any suitable form for stirring the contents of the storage tank 304, and may be driven independently of the drive means 308.

A further embodiment of the dispensing apparatus 401 , shown in Figure 8, combines both a screw pump 476 and a gear pump 454.

The screw pump 476 and gear pump 454 are substantially identical to the screw pump 376 and gear pump 254 described in relation to previous embodiments and, as such, details of there components and their operation will not be described further.

In this embodiment, the drive shaft of one of the spur gears 456 in the gear pump 454 and the shaft 478 of the screw 476 are both integrally formed with the shaft 424 of the water wheel 420. In this way, the speed of rotation of the water wheel 420, the spur gears 456 and the screw 476 are all equal. In other embodiments additional gears or linkages may be included between the water wheel 420 and one or both of the gear pump 454 and screw pump 476, so that one or both of these pumps 454, 476 rotate at a different speed to the water wheel 420. The lower, open end 484 of the tubular housing 482 of the screw pump 478 is located near the bottom of the storage tank 404 and as such will be submerged when the storage tank 404 is filled with concentrate liquid. The outlet 488 of the screw pump 476 is in fluid communication with the inlet 464 of the gear pump 454, and in this example the outlet 488 is connected to the inlet 464 by a connecting tube 496. The outlet 468 of the gear pump 454 is connected to the channel 402 downstream of the water wheel 420 by means of an outlet tube 470.

As the water wheel 420 rotates due to a flow of water along the channel 402, the screw 476 rotates and the helical blade 480 draws concentrate liquid up through the tubular housing 482. The gear pump 454 additionally draws liquid from the outlet 486 of the screw pump 476 and limits or controls the rate at which the concentrate liquid enters the channel 402.

In this embodiment the dispensing apparatus 401 further comprises both a bypass valve 474 located in the outlet tube 470 and agitating means 490 connected to the shaft 478 of the screw pump 476. These components are identical to the same components described in relation to previous embodiments and will not be described further here.

Although the drive means of each of the specific embodiments described above have included a water wheel located within the channel and driven by the flow of the second liquid through the channel, other embodiments of the present invention may include other suitable drive means that are powered by a flow of liquid. As such, the drive means may be of any suitable design to harness a portion of the kinetic energy of the second liquid flowing through the fluid flow conduit and use this to power the pump means. The output of drive means may be directly related to the flow rate of the liquid or to the pressure of the liquid within the channel, or both. Of importance is the requirement that the drive means is powered solely by the flow of liquid and that the drive means is, in turn, connected in such a way to the pump means that the dispensing of the first liquid is directly related to the vo!umetric flow of the second liquid.

The present invention, therefore, provides an improved dispensing apparatus that controls the addition of a quantify of a first liquid, such as concentrated fertilizer, into a flow of a second liquid, such as water, depending on the flow rate of the second liquid, so that the volume ratio of first liquid to second liquid may be kept constant regardless of fluctuations in flow rate of the second liquid.

Claims

1 . A dispensing apparatus for dispensing a measured amount of a first fluid into a flow of a second fluid, the apparatus comprising:

- a main fluid flow conduit through which, in use, the second fluid flows;

a storage vessel for holding a volume of the first fluid; and

2. A dispensing apparatus as claimed in Claim 1 , wherein the first fluid is a liquid.

3. A dispensing apparatus as claimed in Claim 1 or Claim 2, wherein the second fluid is a liquid.

4. A dispensing apparatus as claimed in any preceding claim, wherein the drive means comprises a wheel having a plurality of blades on which the flow of the second fluid acts to turn the wheel.

5. A dispensing apparatus as claimed in Claim 4, wherein the wheel is located fully within the main fluid flow conduit.

6. A dispensing apparatus as claimed in Claim 4 or Claim 5, wherein the pump means comprises a cylinder and a piston, and the drive means comprises a gear and crank to convert the rotational movement of the wheel into linear motion of the piston.

7. A dispensing apparatus as claimed in Claim 8, wherein the pump means and drive means are arranged such that during a first half of a revolution of the wheel the piston moves in a first direction and during a second half of a revolution of the wheel the piston moves in a second direction, opposite to the first direction,

8. A dispensing apparatus as claimed in Claim 7, wherein the pump means further comprises a first valve means located between the storage vessel and the cylinder and a second valve means located between the cylinder and the main fluid flow conduit, said valve means arranged such that, in use, when the piston moves in the first direction the first valve means opens to permit fluid from the storage vessel to enter the cylinder and when the piston moves in the second direction the second valve means opens to permit fluid to flow out of the cylinder into the main fluid flow conduit.

9. A dispensing apparatus as claimed in any of Claims 4 to 8, wherein the pump means comprises two cylinders.

10. A dispensing apparatus as claimed in Claim 9, wherein the drive means is connected to the cylinders such that during a first half of a revolution of the wheel a first cylinder fills with the first fluid from the storage vessel and a second cylinder dispenses a volume of the first fluid into the main fluid flow conduit, and during a second half of a revolution of the wheel the first cylinder dispenses a volume of the first fluid into the main fluid flow conduit and a second cylinder fills with the first fluid from the storage vessel.

1 1. A dispensing apparatus as claimed in Claim 4 or Claim 5, wherein the pump means comprises a gear pump.

12. A dispensing apparatus as claimed in Claim 1 1 , wherein the gear pump is an external gear pump and a shaft of a first spur gear is connected to a shaft of the wheel.

13, A dispensing apparatus as claimed in Claim 1 1 or Claim 12, wherein an inlet of the gear pump is in fluid communication with the storage vessel.

14. A dispensing apparatus, as claimed in Claim 4 or Claim 5, wherein the pump means comprises a screw pump.

15. A dispensing apparatus as claimed in Claim 14, wherein the pump means further comprises a gear pump, an inlet of the gear pump being in fluid communication with an outlet of the screw pump.

16. A dispensing apparatus as claimed in any preceding claim, wherein the main fluid flow conduit is a hose.

17. A dispensing apparatus as claimed in any preceding claim, wherein the main fluid flow conduit includes valve means to permit flow of the second fluid in only one direction.

18. A dispensing apparatus as claimed in any preceding claim, wherein the apparatus further comprises agitation means located in the storage vessel for agitating a volume of the first fluid held in the vessel.

19. A dispensing apparatus as claimed in Claim 18, wherein the agitation means is connected to the drive means.

20. A dispensing apparatus as claimed in any preceding claim, wherein the first fluid is a fertiliser solution and the second fluid is water.

21. A dispensing apparatus as claimed in any of Claims 1 to 19, wherein the first fluid is a detergent solution and the second fluid is water.

22. A method of dispensing a first fluid into a flow of a second fluid, the method comprising the steps of:

mounting drive means at least partially in the conduit such that the flow of the second fluid acts on a portion of the drive means;

23. A dispensing apparatus substantially as herein described with reference to, or as shown in, the accompanying drawings.

24. A method of dispensing a first fluid into a flow of a second fluid substantially as herein described with reference to the accompanying drawings.