It is known to provide portable applicators for dispensing agricultural chemicals, such as pesticides.

In particular, GB-A-2322061 describes a backpack applicator which is to be worn on the back of an operator. The backpack applicator includes a container for holding a supply of flowable material and a flexible hose for feeding the material to a dispenser outlet. The dispenser outlet includes a lever containing a small chamber which is movable between two positions. In one position, the chamber is aligned with a supply pipe for receiving flowable material and, in another position, it is aligned with an outlet for dispensing the material.

Although the dispenser of this previous document works well, it is desirable to provide a dispensing applicator of more simple design and, hence, reduced cost.

In general, previous dispensing applicators have been designed to dispense quantities up to 1g or over 5g.

The present application recognises the need for an applicator design which allows quantities between lg and 5g to be dispensed.

Preferably, the applicator should be adjustable but not complex in design.

According to the present invention, there is provided an applicator for dispensing a predetermined quantity of a flowable material, the applicator comprising: a dispensing chamber having a volume defining the predetermined quantity, the dispensing chamber having an inlet opening for receiving the material and an outlet opening for dispensing the material, wherein:

the inlet and outlet openings are arranged in the dispensing chamber such that with the applicator in one orientation, the material may freely flow through the inlet opening so as to fill the volume of the dispensing chamber without flowing out of the outlet opening and, with the applicator in another orientation, the material held in the volume of the dispensing chamber may be freely dispensed from the outlet opening without material flowing into the dispensing chamber through the inlet opening.

According to the present invention there is also provided a method of dispensing a predetermined quantity of flowable material using the above applicator comprising: orientating the applicator such that flowable material flows into and fills the volume of the dispensing chamber; and orientating the applicator such that flowable material in the volume of the dispensing chamber flows out of the outlet opening.

A reliable applicator may be provided at reduced cost, the applicator also being simple to use, i. e. merely requiring alternation of its orientation.

The applicator is particularly advantageous when used with pellets, for instance of ant bait, since it does not break the bait pellets. Previous applicators with moving parts, for example rotary metering, slides etc, tend to grind the bait to varying degrees. Such bait, once ground in this way is of decreased attraction to the pest in the case of, for instance, ants.

The apparatus is suitable for any granular product, such as an insecticide or bait, which requires accurate measurement and placement without risk of operator contact.

Preferably, the dispensing chamber comprises at least part of an elongate passage. This makes the chamber easy to construct and, also, more versatile. In particular, the volume of the dispensing chamber is

preferably adjustable and, when the dispensing chamber comprises at least part of an elongate passage, an end face of the passage may be movable so as to vary the volume of the dispensing chamber. In this way, a user may selectively vary the amount of flowable material to be dispensed at any one time.

Preferably, the end face of the passage comprises an end face of a plunger which is movably mounted in the passage. In this way, the volume of the dispensing chamber may be conveniently varied.

Preferably, the applicator comprises a feed passage connected to the inlet opening, the inlet and outlet openings being located adjacent one another at a peripheral portion of the dispensing chamber facing the volume of the dispensing chamber and the inlet passage extending generally directly away from the volume of the dispensing chamber. In this way, with the applicator orientated with the dispensing chamber below the inlet and outlet openings, both of the openings will face down into the volume, such that material will flow into the volume through the inlet, but not out through the outlet.

On the otherhand, when the applicator is then in an orientation with the dispensing chamber above the inlet and outlet openings, material in the dispensing chamber can flow out of the outlet opening. In practice, the feed passage connected to the inlet opening will still contain material, such that the material in the dispensing chamber will flow out of the outlet, rather than back out of the inlet. Preferably, the inlet opening and feed passage are positioned and orientated such that this effect is maximised.

Preferably, the feed passage comprises a joint for connection to a supply of material, the joint allowing rotation of at least 180°, thereby allowing rotation of the applicator between said one and said another orientation. This facilitates use of the applicator and reduces wear on the supply pipes, by avoiding the need for them to twist. Additionally, this also enables a

rigid arrangement of supply pipes to be used.

Preferably, a dispensing passage is connected to the outlet opening and extends away from the volume of the dispensing chamber with the angle between the feed and dispensing passages being less than 90° at at least the peripheral portion of the dispensing chamber. In this way, flow of material into the volume from the feed passage is in substantially the opposite direction to flow of material from the volume through the dispensing passage. This facilitates correct operation of the applicator when rotating it between its two orientations.

Preferably, the dispensing chamber and dispensing passage are formed from a single elongate passage and the feed passage branches from the single elongate passage at the division between the dispensing chamber and the dispensing passage.

In this way, the applicator may be constructed in a simple manner.

Preferably, the applicator further comprises an extension to a wall of the feed passage adjacent the outlet opening so as to restrict flow of material from the feed passage to the outlet opening.

In this way, the feed passage is effectively extended into the elongate passage. This can be used to reduce the size of the outlet opening relative to the cross-sectional area of the dispensing chamber volume.

Furthermore, in certain arrangements, it can be used to reduce any flow of material from the inlet opening as the applicator is moved to its dispensing orientation.

Preferably, the flowable material comprises powder or granules. Such materials flow under the influence of gravity, but do exhibit some resistance to flow. In particular, this has the advantage that when one level of the material in the applicator is higher than another, the material will not necessarily flow. For instance, when the applicator is turned to its dispensing orientation, material will not flow back up the feed passage, nor, indeed, will material continue to flow up

out of the feed passage due to any pressure from material in a feeding material container.

The applicator may be incorporated into any form of dispensing device, such as a backpack applicator including a container for holding a supply of the flowable material.

The invention will be more clearly understood from the following description, given by way of example only, with reference to the accompanying drawings, in which: Figure 1 illustrates a portable backpack applicator incorporating an embodiment of the present invention; Figures 2 (a) and (b) illustrate a cross-section of an embodiment of the present invention in its two orientations; and Figures 3 (a) and (b) illustrate an embodiment of the present invention in its two orientations.

Referring to Figure 1, a portable backpack applicator 2 is illustrated. This comprises a frame 4 for supporting a container 6. The container 6 houses a flowable material, such as a powder or granules, and is connected to a supply pipe 8.

As illustrated, the supply pipe 8 in turn connects to an applicator embodying the present invention.

Referring to Figure 2 (a), it will be seen that the flowable material M flows from the supply pipe 8 into a feed passage 12 and, further, into a dispensing chamber 14.

In the illustrated embodiment, the dispensing chamber 14 is formed integrally with a dispensing passage 16 as part of a single elongate passage 18.

In the illustrated embodiment, the end face 20 of the dispensing chamber 14 is defined by the end face of an adjustable plunger 22. It will be seen, therefore, that the volume of the dispensing chamber 14 in the illustrated embodiment is defined by the distance between the inlet opening of the dispensing chamber 14, namely where the feed passage 12 joins the dispensing chamber 14, and the end face 20 of the plunger 22.

For flowable materials, such as powders and granules, orientating the applicator 10 as illustrated in Figure l (a) will result in the material M flowing into and filling the dispensing chamber 14. If, however, the illustrated applicator is then rotated through 180°, as illustrated in Figure 2 (b), then the material will flow out through the dispensing passage 16 and will be dispensed.

As can be seen from Figure 2 (b), because of the relative positioning of the feed passage 12 and the outlet opening 26, although material in the dispensing chamber 14 flows out of the dispensing passage 16, no further material flows from the feed passage 12 into the dispensing chamber 14.

In the preferred embodiment illustrated in the figures, the plunger is adjustably positioned within the elongate passage 18. In particular, the plunger may be selectively moved between various positions along the axis of the elongate passage 18. In this way, the defined volume of the dispensing chamber 14 may be varied, such that the predetermined quantity of material to be dispensed may also be varied.

Various adjustable plunger mechanisms may be used.

The plunger may be freely movable, but gripped by a gripping mechanism. Alternatively, the plunger itself may be threaded, such that it can be turned in and out of the elongate passage 18. As illustrated, a lock nut 28 is provided with a seal 30 to hold and seal the plunger.

As illustrated in Figures 3 (a) and (b), the plunger may be provided with markings along its length enabling the user to set the position of the plunger 22 according to the required amount of material to be dispensed.

By providing applicators with elongate passages 18 of different cross-sectional areas, it is easy to provide a wide variety of adjustable applicators. In particular, it is proposed to provide applicators having a dispensing chamber 14 with a volume which is adjustable between lcc and l0cc and also between l0cc and 30cc.

The inlet and outlet openings of the dispensing chamber 14 are arranged such that material is fed to the dispensing chamber 14 in the first orientation and flows out of the dispensing chamber 14 in the second orientation. This can be achieved with positional arrangements which differ from that illustrated in the figures. However, it will be apparent from the figures that, with the arrangement of the illustrated embodiment, as the angle between the feed passage 12 and dispensing passage 16 is reduced, there is also a reduced possibility of material flowing from the feed passage 12 in the second orientation of Figures 2 (b) and 3 (b).

The illustrated embodiment of Figures 2 (a) and (b) includes an additional feature to assist in preventing flow of material from the feed passage 12 in the second orientation.

In particular, an internal extension 32 is provided to the feed passage 12. The extension 32 enables the feed passage 12 to extend into the elongate passage 18, such that the outlet opening 26 of the dispensing chamber 14 is reduced in size. This also provides a more closely defined volume in the dispensing chamber 14.

As described above, in use, having set the volume of the dispensing chamber 14 by adjusting the position of the plunger 22, the user dispenses predetermined quantities of material by consecutively rotating the actuator 10 between its two orientations. In this way, the dispensing chamber 14 is successively filled and emptied of material.

As illustrated in Figures 3 (a) and (b), a joint 34 may be provided between the supply pipe 8 and the feed passage 12. This joint 34 preferably allows relative rotation between the feed passage 12 and the supply pipe 8. This facilitates rotation of the actuator 10 between its two orientations and also prevents undue wear on the supply pipe 8. Indeed, by using such a joint, it would also be possible to provide a rigid supply pipe 8. In this way, correct functioning of the applicator would not

rely on the user correctly orientating the applicator, since this would be set by the position and orientation of the supply pipe 8.

It will be seen that the feed passage 12 of the illustrated embodiment has a bend 36 along its length.

Clearly, the purpose of this bend is to change the orientation of the applicator as the feed passage 12 rotates about its upstream axis. It will be appreciated that the bend, in itself, is not essential to the invention and that any arrangement which allows the orientation to be changed appropriately is sufficient.

For instance, the feed pipe 12 could be straight, but provided with a joint 34 which rotates at an angle to the axis of the supply passage 12.