CA2320818C - A liquid applicator device - Google Patents
A liquid applicator device Download PDFInfo
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- CA2320818C CA2320818C CA002320818A CA2320818A CA2320818C CA 2320818 C CA2320818 C CA 2320818C CA 002320818 A CA002320818 A CA 002320818A CA 2320818 A CA2320818 A CA 2320818A CA 2320818 C CA2320818 C CA 2320818C
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- liquid
- air
- main reservoir
- valve
- applicator device
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- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01M—CATCHING, TRAPPING OR SCARING OF ANIMALS; APPARATUS FOR THE DESTRUCTION OF NOXIOUS ANIMALS OR NOXIOUS PLANTS
- A01M21/00—Apparatus for the destruction of unwanted vegetation, e.g. weeds
- A01M21/04—Apparatus for destruction by steam, chemicals, burning, or electricity
- A01M21/043—Apparatus for destruction by steam, chemicals, burning, or electricity by chemicals
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C17/00—Hand tools or apparatus using hand held tools, for applying liquids or other fluent materials to, for spreading applied liquids or other fluent materials on, or for partially removing applied liquids or other fluent materials from, surfaces
- B05C17/002—Hand tools or apparatus using hand held tools, for applying liquids or other fluent materials to, for spreading applied liquids or other fluent materials on, or for partially removing applied liquids or other fluent materials from, surfaces with feed system for supplying material from an external source; Supply controls therefor
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- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Pest Control & Pesticides (AREA)
- Toxicology (AREA)
- General Health & Medical Sciences (AREA)
- Insects & Arthropods (AREA)
- Health & Medical Sciences (AREA)
- Wood Science & Technology (AREA)
- Zoology (AREA)
- Environmental Sciences (AREA)
- Mechanical Engineering (AREA)
- Catching Or Destruction (AREA)
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Abstract
A weedkiller applicator (1) comprises an elongated tube (2) forming a liquid inlet at one end having an end cap (3). A block of sponge/foam (12) is provided at the other end of the tube (2) for applying weedkiller by contact with a leaf. Weedkiller is delivered to the foam block (12) through an intermediate chamber (6). The weedkiller is delivered into the chamber (6) by a valve assembly comprising a liquid valve plunger (8) and a non-return air valve (20) having a diaphragm (24). The air inlet to the tube (2) is located above the liquid discharge opening from the tube (2) to provide a uniform rate of flow of liquid to the foam block (12) irrespective of the head of liquid in the tube (2).
Description
~~A liquid applicator device"
Introduction The present invention relates to a liquid applicator device particularly for applying weedkiller.
One of the major problems encountered in gardening, particularly for the amateur in the small garden, is the need to apply weedkiller to weeds in a controlled 1o manner, whereby the weedkiller is not applied to the plants that it is desired to keep, such as flowers, vegetables and the like. It has been known to tackle this problem by the use of a number of different weed applicators however, none of the conventional weed applicators is entirely satisfactory.
~ s One particular problem is in applying the weedkiller in a manner that is effective and yet easily implemented by the user. Conventional applicators require careful use to avoid spreading the weedkiller to adjacent plants. There are also diffllculties in controlling the amount of weedkiller applied and to controlling the flow of weedkiller generally.
The present invention is therefore directed towards providing a liquid applicator device which will overcome at least some of these problems.
Another related problem in horticultural situations is the controlled feeding and or 2s watering of seedlings and plants.
The invention also relates to liquid dispensing devices in general which conventionally incorporate either a permanent air intake or an air inlet that can be opened and shut as required together with a discharge opening remote from the 3o inlet. One problem with such conventional liquid dispensing devices is that the flow rate varies. In particular, in the case of a container the flow rate varies WO 98/34476 PCTlIE98/00009 depending on the quantity of liquid within the container, as the head of liquid above the outlet determines the flow rate. When it is desired to provide containers which, irrespective of the amount of liquid contained therein, will discharge at a constant flow rate, relatively expensive pieces of equipment are required such as s for example positive displacement pumps and the like metering devices.
There are many situations where such expensive equipment is impractical and in which it is required to control the rate of discharge of a liquid, especially from a container, which rate of discharge is independent of the head height of liquid stored within the container. One can readily consider such medical uses as intravenous feeding, saline drips and the like. Similarly, in industry and in the home and ofl~ce there are many situations where the discharge of liquid in a controlled manner is extremely desirable whether it be for such mundane tasks as the application of adhesives, paints, nail polishes, or indeed any form of liquid 15 within a container.
The invention is also directed to a liquid dispensing device which will overcome at least some of the problems described above.
2o Statements of Invention According to the invention there is provided a weedkiller liquid applicator device comprising:
25 a main reservoir for weedkiller liquid to be applied; and a liquid retention means for receiving an amount of liquid from the main reservoir corresponding to multiple applicator doses and to deliver a substantially uniform single dose of liquid on application.
WO 98/34476 p~/~9g~pppp9 In one particularly preferred embodiment of the invention the liquid retention means is of a material to store multiple applicator doses and to apply a single dose on contact application.
Preferably the liquid retention means is of cellular structure. Most preferably the liquid retention means is of a foam material, especially a polyurethane foam material.
In an especially preferred embodiment of the invention the device includes control t o means for regulating the delivery of liquid through a discharge opening from the main reservoir.
Preferably the control means includes an air regulator for controlling the flow of air through an air inlet to provide substantially uniform flow of liquid from the main reservoir means.
Most preferably the control means includes a liquid discharge valve which is movable by an actuating means from a closed position closing the liquid discharge opening to an open position for delivery of liquid.
Ideally the air inlet to the main reservoir is located above the liquid discharge opening from the main reservoir. Most preferably the air inlet is located a distance above the liquid discharge outlet corresponding to a desired delivery flow rate through the liquid discharge opening.
In one embodiment of the invention the air regulator is provided by a non-return valve to prevent flow of liquid through the air inlet. Preferably the non-return valve includes a diaphragm which is movable by air pressure from a normally closed position closing the air inlet to an open position for delivery of air through the air inlet.
Introduction The present invention relates to a liquid applicator device particularly for applying weedkiller.
One of the major problems encountered in gardening, particularly for the amateur in the small garden, is the need to apply weedkiller to weeds in a controlled 1o manner, whereby the weedkiller is not applied to the plants that it is desired to keep, such as flowers, vegetables and the like. It has been known to tackle this problem by the use of a number of different weed applicators however, none of the conventional weed applicators is entirely satisfactory.
~ s One particular problem is in applying the weedkiller in a manner that is effective and yet easily implemented by the user. Conventional applicators require careful use to avoid spreading the weedkiller to adjacent plants. There are also diffllculties in controlling the amount of weedkiller applied and to controlling the flow of weedkiller generally.
The present invention is therefore directed towards providing a liquid applicator device which will overcome at least some of these problems.
Another related problem in horticultural situations is the controlled feeding and or 2s watering of seedlings and plants.
The invention also relates to liquid dispensing devices in general which conventionally incorporate either a permanent air intake or an air inlet that can be opened and shut as required together with a discharge opening remote from the 3o inlet. One problem with such conventional liquid dispensing devices is that the flow rate varies. In particular, in the case of a container the flow rate varies WO 98/34476 PCTlIE98/00009 depending on the quantity of liquid within the container, as the head of liquid above the outlet determines the flow rate. When it is desired to provide containers which, irrespective of the amount of liquid contained therein, will discharge at a constant flow rate, relatively expensive pieces of equipment are required such as s for example positive displacement pumps and the like metering devices.
There are many situations where such expensive equipment is impractical and in which it is required to control the rate of discharge of a liquid, especially from a container, which rate of discharge is independent of the head height of liquid stored within the container. One can readily consider such medical uses as intravenous feeding, saline drips and the like. Similarly, in industry and in the home and ofl~ce there are many situations where the discharge of liquid in a controlled manner is extremely desirable whether it be for such mundane tasks as the application of adhesives, paints, nail polishes, or indeed any form of liquid 15 within a container.
The invention is also directed to a liquid dispensing device which will overcome at least some of the problems described above.
2o Statements of Invention According to the invention there is provided a weedkiller liquid applicator device comprising:
25 a main reservoir for weedkiller liquid to be applied; and a liquid retention means for receiving an amount of liquid from the main reservoir corresponding to multiple applicator doses and to deliver a substantially uniform single dose of liquid on application.
WO 98/34476 p~/~9g~pppp9 In one particularly preferred embodiment of the invention the liquid retention means is of a material to store multiple applicator doses and to apply a single dose on contact application.
Preferably the liquid retention means is of cellular structure. Most preferably the liquid retention means is of a foam material, especially a polyurethane foam material.
In an especially preferred embodiment of the invention the device includes control t o means for regulating the delivery of liquid through a discharge opening from the main reservoir.
Preferably the control means includes an air regulator for controlling the flow of air through an air inlet to provide substantially uniform flow of liquid from the main reservoir means.
Most preferably the control means includes a liquid discharge valve which is movable by an actuating means from a closed position closing the liquid discharge opening to an open position for delivery of liquid.
Ideally the air inlet to the main reservoir is located above the liquid discharge opening from the main reservoir. Most preferably the air inlet is located a distance above the liquid discharge outlet corresponding to a desired delivery flow rate through the liquid discharge opening.
In one embodiment of the invention the air regulator is provided by a non-return valve to prevent flow of liquid through the air inlet. Preferably the non-return valve includes a diaphragm which is movable by air pressure from a normally closed position closing the air inlet to an open position for delivery of air through the air inlet.
In one arrangement the liquid discharge valve actuating means comprises a plunger projecting from the valve, the plunger being pushed against a surface to open the valve.
In a preferred embodiment of the invention the device includes an intermediate chamber between the main reservoir and the liquid retention means, liquid being delivered from the main reservoir into the intermediate chamber. The intermediate chamber assists in controlled delivery of liquid to the liquid retention means.
to Preferably the main reservoir comprises an elongate tube, one end of the tube defining a liquid inlet and the liquid retention means being mounted at the other end of the tube. Usually the liquid inlet is closed by a closure cap.
t 5 In another aspect the invention provides a liquid dispensing device having a liquid discharge opening and an air inlet wherein the air inlet is located above the liquid discharge opening to provide a substantially uniform flow of liquid from the dispensing device. Preferably the air inlet is located a distance above the liauid discharge outlet corresponding to a desired delivery flow rate through the 2o discharge opening.
In a preferred embodiment of the invention the device includes an air regulator for controlling the flow of air through the air inlet to provide a substantially uniform flow of liquid. Preferably the air regulator is provided by a non-return valve to 25 prevent the flow of liquid through the air inlet. In a preferred arrangement the non-return valve includes a diaphragm which is movable by air pressure from a normally closed position closing the air inlet to an open position for delivery of air through the air inlet.
In one embodiment of the invention the device includes a liquid discharge valve which is movable by an actuating means from a closed position closing the liquid discharge opening to an open position for delivery of liquid.
s Ideally the non-return air valve is located above the discharge opening, and preferably when this happens the air inlet is at a position where its outlet into the container will always be within the liquid in the container until almost all the last bit of liquid has been discharged out of the container.
to The discharge opening may incorporate a normally closed liquid outlet valve operative by a plunger projecting therefrom whereby on pushing the plunger against the surface the valve opens and liquid is discharged.
In an embodiment of the invention a liquid containing material may be mounted ~ 5 adjacent the discharge opening for retention of liquid discharged therefrom.
A particularly suitable construction is to incorporate both the normally closed liquid outlet and the non-return air valve in the one discharge opening assembly.
With this arrangement which is particularly suitable for example for the 2o application of weedkiller the liquid container is an elongated tube, the bore forming a closure at one end for liquid inlet and a discharge opening at the other end for reception of the combined air inlet and discharge valve as hereinbefore described.
2s It is also envisaged that a discharge valve for a sealed liquid container may be provided according to the invention in which the discharge valve incorporates a non-return air inlet. It will be appreciated that such a valve can be used for almost any liquid container requiring a relatively steady discharge output.
WO 98134476 p~~9g/pppp9 For example, when a saline drip needs to be dispensed the discharge valve may be a separate unit connected to tubing and having an inlet for connection to an infusion bottle.
s Brief Description of t_he Drawings The invention will be more clearly understood from the following description thereof given by way of example only with reference to the accompanying drawings, in which:-Fig. 1 is a perspective view from one end of a weedkiller applicator according to the invention;
Fig. 2 is a perspective view from the other end of the applicator;
is Fig. 3 is an exploded perspective, partially cross sectional view of the applicator;
Fig. 4 is a perspective view of some of the parts, assembled;
Fig. 5 is a cross sectional view of the applicator with a liquid discharge valve closed;
Fig. 6 is a cross sectional view of an air regulator part of the applicator in the position of Fig. 6;
Fig. 7 is a cross sectional view of the applicator with a liquid discharge valve open; and 3o Fig. 8 is a cross sectional view of an air regulator part of the applicator in the position of Fig. 7.
Detailed Description Referring to the drawings there is illustrated a weedkiller applicator indicated generally by the reference numeral 1, comprising a main reservoir for liquid s defined by a container 2 in the shape of an elongated tube forming a liquid inlet having an end cap 3 mounted on the end of the container 2. Remote from the end cap 3 is a discharge valve assembly indicated generally by the reference numeral 4.
The discharge valve assembly 4 comprises a cylindrical body member divided into two compartments, namely an interior compartment 5 communicating directly 1o with the interior of the container 2 and an intermediate chamber defined by an exterior compartment 6 separated therefrom by a partition wall 7. Mounted in the partition wall 7 is a valve plunger 8 having a plurality of axially arranged liquid passageways 9. A spring 10 biases the valve plunger 8 into a normally closed position. Mounted on the end of the valve plunger 8 projecting into the exterior t s compartment 6 is an in-line actuator 11. A block of liquid retaining material, in this case a portion of foam/sponge 12, surrounds the actuator 11 and bears against an annular flange 13 having a plurality of holes 14. The flange 13 is a press-fit within the discharge valve assembly 4 and the sponge 12 which is of polyurethane material is cut to have an undersize bore and an oversize outer 2o diameter to form a force-fit due to its own elasticity.
The foam/sponge block 12 defines a liquid retention means for receiving an amount of liquid from the main reservoir defined by the tube 2 corresponding to multiple applicator doses. The cellular structure of the foam/sponge material also 2s delivers a substantially uniform dose of liquid by contact application to the leaves of a weed. The flow of weedkiller liquid from the container 2 into the intermediate chamber 6 is controlled by a control means which regulates the delivery of liquid through a discharge opening into the liquid passageways 9.
The control means comprises an air regulator for controlling the flow of air through an 3o air inlet to provide substantially uniform flow of liquid from the container 2 into the intermediate chamber 6. The control means also includes the liquid discharge valve 8 which is movable by the actuator 11 from a closed position closing the liquid discharge opening (Fig. 5) to an upper position (Fig. 7) for delivery of liquid into the intermediate chamber 6. The chamber 6 spreads the liquid partially across the top of the sponge/foam 12 which soaks the liquid through the holes s in the wall 13.
The control means defined in this case by the air regulator and liquid discharge valve are mounted together in the valve assembly 4.
The air regulator comprises a non-return air valve 20 which is mounted on a spigot 26 extending upwardly from the partition wall 7. The non-return air valve 20 comprises a bored valve stem 21 having a bore 22 mounted within a rigid tube 23. A diaphragm 24 covers the bore 22 and is retained in position by an end cap 25 having openings 27 communicating with the interior of the container 2.
In use, depression of the actuator 11 against any hard surface causes the plunger 8 to move upwards within the interior compartment 5 and thus within the container 2 allowing weedkiller liquid to flow down the liquid passageways 9 into the exterior compartment 6 and then through the holes 14 in the annular Mange 13 onto the sponge 12 which is then wetted with the weedkiller: The flow of liquid is indicated by single headed arrows in Fig. 7. The air valve 20 ensures that there is a constant rate of flow. There will always be air in the exterior comparnnent which will act on the underneath of the diaphragm 24 and will raise it to allow air discharge out through the end cap 25 into the liquid in the container 2 until equalisation of pressure on the diaphragm 24. Thus the pressure for discharge will always be constant and equal to the pressure obtained at the bottom of a liquid column of height x, where x is the difference between B and C on the drawing, i.e.
between liquid outlet and air outlet.
3o The diaphragm 24 effectively floats between an open or sealed position and once the container is open to the atmosphere e.g. on filling it will be sealed shut by the WO 98134476 p~~gg/pppp9 head of the liquid. The flow of air is schematically illustrated by double-headed arrows in Figs. 7 and 8.
In the applicator of the invention when the liquid valve is opened, the liquid wants to discharge at a rate that is consistent with pressure generated by the water column at the valve. For this to happen air must enter the enclosed tube.
However, the air intake is governed by the liquid pressure opposing the entry of air at the air entry point. Should that point be just above the discharge valve then the pressure opposing air entry will approximate to the liquid pressure at the t o discharge valve. As a consequence the rate at which air can enter is dependent on a small pressure differential. This in turn determines the rate at which liquid can discharge, irrespective of the height of liquid within the tube.
In the invention, the air valve is fitted with a diaphragm so that it too acts as a one ~ s way valve. This is important to prevent liquid leakage when the tube is being filled, otherwise the system would work without the diaphragm. It is however true to say that the diaphragm senses every minute variation of pressure in the liquid column and responds by instantly correcting the rate of air intake.
2o Given a constant flow rate the dose size is now determined by the time interval between the opening and closing of the liquid discharge valve. In the invention the sponge receives a full dose (equivalent to some 30 weed doses) when the valve plunger is quickly pressed and released.
2s The applicator of the invention may be used substantially continuously or on an intermittent basis. For example, it may be used to treat a concentration of weeds in a small area or a number of weeds spread over a large area. Because of the liquid retention means, especially in the form of a cellular structure, particularly a foam or sponge a reservoir of a multitude of doses (such as 30 doses) is provided.
3o This retention means may be used after a single charge to treat weeds in a local area or spread over a wide area without interruption to re-charge the applicator.
WO 98/3447b PCT/IE98/U0009 More particularly because of the construction of the liquid retention means, a contact liquid film is easily applied to the leaves of the weed for effective treatment.
s In addition, by virtue of the liquid retention means blockages of the working parts of the applicator are avoided. Because only a single charge is required for multiple applications contact with the soil is minimised. Weed treatment is achieved by sponge/foam to leaf contact, without pressing. The sponge/foam effectively acts as a barrier, preventing soil from contacting the moving parts.
s o Further, each re-charge flushes the sponge/foam.
The applicator is readily refilled without contacting parts through which weedkiller has passed. For charging weedkiller concentrate to which water may be added in the tube the closure ca.p may be of a volume or have an indicator 1 s marks) corresponding to a desired amount of liquid concentrate required for make-up of a weedkiller liquid.
It is believed that there is a constant flow of liquid because effectively the in-flow of the air at the level C as indicated in the drawing is in the form of bubbles which 2o will be relatively regular sized. Bubble formation requires a certain excess pressure, more or less independent of flow rate. Thus, the following appears to be the position when the container 2 is sealed. Air enters the container at the level C
and liquid is flowing out of the container at level B. The following appears to be a possible mathematical explanation.
~P = pa - p~ (1) p, = air pressure p~ = liquid pressure at C
p~ - pn = - p g x (2) pd = liquid pressure at B where:x -3o height difference between B and C
p = density/specific gravity Flow rate cQ = pn - pa (3) Q = Flow rate c = constant {Posseuilles Law}
Pn = pa + cQ (4) adding (2) + (4) pr=pa+cQ-p g x pr - pa = CQ - P g x - Op=cQ_P 8 x cQ=P g x-~P
when p g x = 0p no flow will occur For flow then x > DP
Pg 2o This is a possible explanation of why constant flow is achieved.
Another possible way of viewing how tire invention works is that as the entry of the air is through the liquid this entry is being opposed by the pressure generated by the column of liquid above the entry point and it is the differential between the negative pressure generated above the liquid and this positive pressure that controls the flow of air. It is the natural balance between these two opposite pressures that occurs as the liquid empties which achieves this steady flow rate.
The invention is particularly applicable to constant rate watering or feeding 3o systems for horticultural use. It will work particularly well with remotely sited containers.
It is envisaged that with the correct choice of air valve very accurate control of flow can be obtained either through varying the height of the air outlet above the liquid discharge outlet, the so called x dimension.
s The invention is not limited to the embodiments hereinbefore described which may be varied in both construction and detail.
In a preferred embodiment of the invention the device includes an intermediate chamber between the main reservoir and the liquid retention means, liquid being delivered from the main reservoir into the intermediate chamber. The intermediate chamber assists in controlled delivery of liquid to the liquid retention means.
to Preferably the main reservoir comprises an elongate tube, one end of the tube defining a liquid inlet and the liquid retention means being mounted at the other end of the tube. Usually the liquid inlet is closed by a closure cap.
t 5 In another aspect the invention provides a liquid dispensing device having a liquid discharge opening and an air inlet wherein the air inlet is located above the liquid discharge opening to provide a substantially uniform flow of liquid from the dispensing device. Preferably the air inlet is located a distance above the liauid discharge outlet corresponding to a desired delivery flow rate through the 2o discharge opening.
In a preferred embodiment of the invention the device includes an air regulator for controlling the flow of air through the air inlet to provide a substantially uniform flow of liquid. Preferably the air regulator is provided by a non-return valve to 25 prevent the flow of liquid through the air inlet. In a preferred arrangement the non-return valve includes a diaphragm which is movable by air pressure from a normally closed position closing the air inlet to an open position for delivery of air through the air inlet.
In one embodiment of the invention the device includes a liquid discharge valve which is movable by an actuating means from a closed position closing the liquid discharge opening to an open position for delivery of liquid.
s Ideally the non-return air valve is located above the discharge opening, and preferably when this happens the air inlet is at a position where its outlet into the container will always be within the liquid in the container until almost all the last bit of liquid has been discharged out of the container.
to The discharge opening may incorporate a normally closed liquid outlet valve operative by a plunger projecting therefrom whereby on pushing the plunger against the surface the valve opens and liquid is discharged.
In an embodiment of the invention a liquid containing material may be mounted ~ 5 adjacent the discharge opening for retention of liquid discharged therefrom.
A particularly suitable construction is to incorporate both the normally closed liquid outlet and the non-return air valve in the one discharge opening assembly.
With this arrangement which is particularly suitable for example for the 2o application of weedkiller the liquid container is an elongated tube, the bore forming a closure at one end for liquid inlet and a discharge opening at the other end for reception of the combined air inlet and discharge valve as hereinbefore described.
2s It is also envisaged that a discharge valve for a sealed liquid container may be provided according to the invention in which the discharge valve incorporates a non-return air inlet. It will be appreciated that such a valve can be used for almost any liquid container requiring a relatively steady discharge output.
WO 98134476 p~~9g/pppp9 For example, when a saline drip needs to be dispensed the discharge valve may be a separate unit connected to tubing and having an inlet for connection to an infusion bottle.
s Brief Description of t_he Drawings The invention will be more clearly understood from the following description thereof given by way of example only with reference to the accompanying drawings, in which:-Fig. 1 is a perspective view from one end of a weedkiller applicator according to the invention;
Fig. 2 is a perspective view from the other end of the applicator;
is Fig. 3 is an exploded perspective, partially cross sectional view of the applicator;
Fig. 4 is a perspective view of some of the parts, assembled;
Fig. 5 is a cross sectional view of the applicator with a liquid discharge valve closed;
Fig. 6 is a cross sectional view of an air regulator part of the applicator in the position of Fig. 6;
Fig. 7 is a cross sectional view of the applicator with a liquid discharge valve open; and 3o Fig. 8 is a cross sectional view of an air regulator part of the applicator in the position of Fig. 7.
Detailed Description Referring to the drawings there is illustrated a weedkiller applicator indicated generally by the reference numeral 1, comprising a main reservoir for liquid s defined by a container 2 in the shape of an elongated tube forming a liquid inlet having an end cap 3 mounted on the end of the container 2. Remote from the end cap 3 is a discharge valve assembly indicated generally by the reference numeral 4.
The discharge valve assembly 4 comprises a cylindrical body member divided into two compartments, namely an interior compartment 5 communicating directly 1o with the interior of the container 2 and an intermediate chamber defined by an exterior compartment 6 separated therefrom by a partition wall 7. Mounted in the partition wall 7 is a valve plunger 8 having a plurality of axially arranged liquid passageways 9. A spring 10 biases the valve plunger 8 into a normally closed position. Mounted on the end of the valve plunger 8 projecting into the exterior t s compartment 6 is an in-line actuator 11. A block of liquid retaining material, in this case a portion of foam/sponge 12, surrounds the actuator 11 and bears against an annular flange 13 having a plurality of holes 14. The flange 13 is a press-fit within the discharge valve assembly 4 and the sponge 12 which is of polyurethane material is cut to have an undersize bore and an oversize outer 2o diameter to form a force-fit due to its own elasticity.
The foam/sponge block 12 defines a liquid retention means for receiving an amount of liquid from the main reservoir defined by the tube 2 corresponding to multiple applicator doses. The cellular structure of the foam/sponge material also 2s delivers a substantially uniform dose of liquid by contact application to the leaves of a weed. The flow of weedkiller liquid from the container 2 into the intermediate chamber 6 is controlled by a control means which regulates the delivery of liquid through a discharge opening into the liquid passageways 9.
The control means comprises an air regulator for controlling the flow of air through an 3o air inlet to provide substantially uniform flow of liquid from the container 2 into the intermediate chamber 6. The control means also includes the liquid discharge valve 8 which is movable by the actuator 11 from a closed position closing the liquid discharge opening (Fig. 5) to an upper position (Fig. 7) for delivery of liquid into the intermediate chamber 6. The chamber 6 spreads the liquid partially across the top of the sponge/foam 12 which soaks the liquid through the holes s in the wall 13.
The control means defined in this case by the air regulator and liquid discharge valve are mounted together in the valve assembly 4.
The air regulator comprises a non-return air valve 20 which is mounted on a spigot 26 extending upwardly from the partition wall 7. The non-return air valve 20 comprises a bored valve stem 21 having a bore 22 mounted within a rigid tube 23. A diaphragm 24 covers the bore 22 and is retained in position by an end cap 25 having openings 27 communicating with the interior of the container 2.
In use, depression of the actuator 11 against any hard surface causes the plunger 8 to move upwards within the interior compartment 5 and thus within the container 2 allowing weedkiller liquid to flow down the liquid passageways 9 into the exterior compartment 6 and then through the holes 14 in the annular Mange 13 onto the sponge 12 which is then wetted with the weedkiller: The flow of liquid is indicated by single headed arrows in Fig. 7. The air valve 20 ensures that there is a constant rate of flow. There will always be air in the exterior comparnnent which will act on the underneath of the diaphragm 24 and will raise it to allow air discharge out through the end cap 25 into the liquid in the container 2 until equalisation of pressure on the diaphragm 24. Thus the pressure for discharge will always be constant and equal to the pressure obtained at the bottom of a liquid column of height x, where x is the difference between B and C on the drawing, i.e.
between liquid outlet and air outlet.
3o The diaphragm 24 effectively floats between an open or sealed position and once the container is open to the atmosphere e.g. on filling it will be sealed shut by the WO 98134476 p~~gg/pppp9 head of the liquid. The flow of air is schematically illustrated by double-headed arrows in Figs. 7 and 8.
In the applicator of the invention when the liquid valve is opened, the liquid wants to discharge at a rate that is consistent with pressure generated by the water column at the valve. For this to happen air must enter the enclosed tube.
However, the air intake is governed by the liquid pressure opposing the entry of air at the air entry point. Should that point be just above the discharge valve then the pressure opposing air entry will approximate to the liquid pressure at the t o discharge valve. As a consequence the rate at which air can enter is dependent on a small pressure differential. This in turn determines the rate at which liquid can discharge, irrespective of the height of liquid within the tube.
In the invention, the air valve is fitted with a diaphragm so that it too acts as a one ~ s way valve. This is important to prevent liquid leakage when the tube is being filled, otherwise the system would work without the diaphragm. It is however true to say that the diaphragm senses every minute variation of pressure in the liquid column and responds by instantly correcting the rate of air intake.
2o Given a constant flow rate the dose size is now determined by the time interval between the opening and closing of the liquid discharge valve. In the invention the sponge receives a full dose (equivalent to some 30 weed doses) when the valve plunger is quickly pressed and released.
2s The applicator of the invention may be used substantially continuously or on an intermittent basis. For example, it may be used to treat a concentration of weeds in a small area or a number of weeds spread over a large area. Because of the liquid retention means, especially in the form of a cellular structure, particularly a foam or sponge a reservoir of a multitude of doses (such as 30 doses) is provided.
3o This retention means may be used after a single charge to treat weeds in a local area or spread over a wide area without interruption to re-charge the applicator.
WO 98/3447b PCT/IE98/U0009 More particularly because of the construction of the liquid retention means, a contact liquid film is easily applied to the leaves of the weed for effective treatment.
s In addition, by virtue of the liquid retention means blockages of the working parts of the applicator are avoided. Because only a single charge is required for multiple applications contact with the soil is minimised. Weed treatment is achieved by sponge/foam to leaf contact, without pressing. The sponge/foam effectively acts as a barrier, preventing soil from contacting the moving parts.
s o Further, each re-charge flushes the sponge/foam.
The applicator is readily refilled without contacting parts through which weedkiller has passed. For charging weedkiller concentrate to which water may be added in the tube the closure ca.p may be of a volume or have an indicator 1 s marks) corresponding to a desired amount of liquid concentrate required for make-up of a weedkiller liquid.
It is believed that there is a constant flow of liquid because effectively the in-flow of the air at the level C as indicated in the drawing is in the form of bubbles which 2o will be relatively regular sized. Bubble formation requires a certain excess pressure, more or less independent of flow rate. Thus, the following appears to be the position when the container 2 is sealed. Air enters the container at the level C
and liquid is flowing out of the container at level B. The following appears to be a possible mathematical explanation.
~P = pa - p~ (1) p, = air pressure p~ = liquid pressure at C
p~ - pn = - p g x (2) pd = liquid pressure at B where:x -3o height difference between B and C
p = density/specific gravity Flow rate cQ = pn - pa (3) Q = Flow rate c = constant {Posseuilles Law}
Pn = pa + cQ (4) adding (2) + (4) pr=pa+cQ-p g x pr - pa = CQ - P g x - Op=cQ_P 8 x cQ=P g x-~P
when p g x = 0p no flow will occur For flow then x > DP
Pg 2o This is a possible explanation of why constant flow is achieved.
Another possible way of viewing how tire invention works is that as the entry of the air is through the liquid this entry is being opposed by the pressure generated by the column of liquid above the entry point and it is the differential between the negative pressure generated above the liquid and this positive pressure that controls the flow of air. It is the natural balance between these two opposite pressures that occurs as the liquid empties which achieves this steady flow rate.
The invention is particularly applicable to constant rate watering or feeding 3o systems for horticultural use. It will work particularly well with remotely sited containers.
It is envisaged that with the correct choice of air valve very accurate control of flow can be obtained either through varying the height of the air outlet above the liquid discharge outlet, the so called x dimension.
s The invention is not limited to the embodiments hereinbefore described which may be varied in both construction and detail.
Claims (11)
1. A weedkiller liquid applicator device comprising:
a main reservoir for weedkiller liquid;
a liquid retention means for receiving an amount of liquid from the main reservoir corresponding to multiple doses and for delivery of a substantially uniform single dose of liquid, on application;
an intermediate chamber between the main reservoir and the liquid retention means, the intermediate chamber being separated from the main reservoir by a partition;
the partition having an air opening from the exterior compartment and a liquid discharge opening to the exterior compartment;
a liquid discharge valve which is movable by an actuation means from a closed position closing the liquid discharge opening to an open position for delivery of liquid from the main reservoir into the exterior compartment;
a tubular member extending into the main reservoir from the air opening in the partition, the tubular member having an outlet through which air is delivered into the main reservoir;
the air outlet from the tubular member into the main reservoir being located above the liquid discharge opening in the partition; and an air regulator for controlling the flow of air from the exterior compartment into the main reservoir.
a main reservoir for weedkiller liquid;
a liquid retention means for receiving an amount of liquid from the main reservoir corresponding to multiple doses and for delivery of a substantially uniform single dose of liquid, on application;
an intermediate chamber between the main reservoir and the liquid retention means, the intermediate chamber being separated from the main reservoir by a partition;
the partition having an air opening from the exterior compartment and a liquid discharge opening to the exterior compartment;
a liquid discharge valve which is movable by an actuation means from a closed position closing the liquid discharge opening to an open position for delivery of liquid from the main reservoir into the exterior compartment;
a tubular member extending into the main reservoir from the air opening in the partition, the tubular member having an outlet through which air is delivered into the main reservoir;
the air outlet from the tubular member into the main reservoir being located above the liquid discharge opening in the partition; and an air regulator for controlling the flow of air from the exterior compartment into the main reservoir.
2. A liquid applicator device as claimed in claim 1 wherein the liquid retention means is of a material to store multiple applicator doses and to apply a single dose on contact application.
3. A liquid applicator device as claimed in claim 1 or 2 wherein the liquid retention means is of cellular structure.
4. A liquid applicator means as claimed in claim 3 wherein the liquid retention means is of a foam material.
5. A liquid applicator means as claimed in claim 4 wherein the foam material is a polyurethane foam.
6. A liquid applicator device as claimed in any one of claims 1 to 5 wherein the air inlet is located a distance above the liquid discharge outlet corresponding to a desired delivery flow rate through the liquid discharge opening.
7. A liquid applicator device as claimed in any one of claims 1 to 6 wherein the air regulator is provided by a non-return valve to prevent flow of liquid into the tubular member from the main reservoir.
8. A liquid applicator device as claimed in claim 7 wherein the non-return valve includes a diaphragm which is movable by air pressure from a normally closed position closing the air opening into the main reservoir to an open position for delivery of air from the exterior compartment through the air opening into the main reservoir.
9. A liquid applicator device as claimed in any one of claims 1 to 8 wherein the liquid discharge valve actuation means comprises a plunger projecting from the valve, the plunger being pushed against a surface to open the valve.
10. A liquid applicator device as claimed in any one of claims 1 to 9 wherein the main reservoir comprises an elongate tube, one end of the tube defining a liquid inlet and the liquid retention means being mounted at the other end of the tube.
11. A liquid applicator device as claimed in claim 10 wherein the liquid inlet is closed by a closure cap.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IES970087 | 1997-02-11 | ||
| IE970087 | 1997-02-11 | ||
| PCT/IE1998/000009 WO1998034476A1 (en) | 1997-02-11 | 1998-02-11 | A liquid applicator device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2320818A1 CA2320818A1 (en) | 1998-08-13 |
| CA2320818C true CA2320818C (en) | 2004-03-16 |
Family
ID=11041369
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002320818A Expired - Fee Related CA2320818C (en) | 1997-02-11 | 1998-02-11 | A liquid applicator device |
Country Status (5)
| Country | Link |
|---|---|
| AU (1) | AU6004898A (en) |
| CA (1) | CA2320818C (en) |
| GB (1) | GB2321848B (en) |
| IE (1) | IE980100A1 (en) |
| WO (1) | WO1998034476A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2363977B (en) * | 2000-06-20 | 2003-07-02 | London Oil Refining Company Lt | A toilet cleaning apparatus |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2979757A (en) * | 1959-11-16 | 1961-04-18 | Smith Norman | Weed-killer applicator |
| FR1286174A (en) * | 1961-04-05 | 1962-03-02 | Device for weed control using chemicals harmful to plants | |
| GB1303967A (en) * | 1971-07-19 | 1973-01-24 | ||
| US4357779A (en) * | 1979-09-04 | 1982-11-09 | Maddock Mitchell E | Hand held liquid herbicide applicator |
| GB2082449A (en) * | 1980-07-26 | 1982-03-10 | Walker William Edward | Liquid applicators |
| GB2120915B (en) * | 1982-05-11 | 1985-05-22 | Richard John Cox | Application device |
| CA1297071C (en) * | 1985-04-24 | 1992-03-10 | Kevin Geoffrey Baumber | Applicator |
| US5216833A (en) * | 1991-09-06 | 1993-06-08 | Longer David E | Herbicide applicator |
| US5555673A (en) * | 1994-11-14 | 1996-09-17 | Smith; Wayne H. | Method and apparatus for applying liquid |
-
1998
- 1998-02-11 AU AU60048/98A patent/AU6004898A/en not_active Abandoned
- 1998-02-11 GB GB9802939A patent/GB2321848B/en not_active Expired - Fee Related
- 1998-02-11 WO PCT/IE1998/000009 patent/WO1998034476A1/en active Application Filing
- 1998-02-11 IE IE980100A patent/IE980100A1/en not_active IP Right Cessation
- 1998-02-11 CA CA002320818A patent/CA2320818C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| GB9802939D0 (en) | 1998-04-08 |
| IE980100A1 (en) | 1998-08-12 |
| WO1998034476A1 (en) | 1998-08-13 |
| CA2320818A1 (en) | 1998-08-13 |
| GB2321848A (en) | 1998-08-12 |
| GB2321848B (en) | 2000-12-27 |
| AU6004898A (en) | 1998-08-26 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |
Effective date: 20130211 |