GB2113182A - Metering device - Google Patents

Abstract

A metering device for granular materials uses opposed chambers (C, D) which alternately fill and empty by gravity as the device is rotated about an inclined axis. The granular material is prevented from entering the chamber in the upper (discharging) position or leaving the chamber in the lower (filling) position by means of weirs. A hand-held fertiliser dispenser consists of a tubular reservoir (A) from which granular fertiliser flows into the lower chamber C. When the whole is rotated about its axis through 180 DEG the fertiliser in the newly upper chamber will flow out via the discharge tube (E), and the newly lower chamber will be filled as before. The volume dispensed each time depends upon the size of the chambers which may be varied by unscrewing threaded caps on the chambers or by selecting appropriate chamber pairs. <IMAGE>

Description

SPECIFICATION Metering device for granular materials In horticultural practice it is frequently necessary to apply granular fertilizers or pesticides in roughly measured doses to plants in pots or in the open ground. Existing machines for this purpose are rather slow to use, costly and complicated, with moving parts which wear or get stuck. The slowness arises partly from the metering machinery being at hand level so that the fertilizer or other granular material then has to travel down a long tube to the ground or pot before the device can be moved to the next plant.

The present invention overcomes these difficulties by having the metering part only a few inches from the ground and having no moving parts.

The invention comprises a metering device for granular materials consisting of two opposed chambers connected to a reservoir above and an outlet below, which are rotated about an axis (running through the reservoir and the outlet) inclined between 100 and 800 from the vertical.

In this way each chamber fills from the reservoir when in the lower position and discharges its contents through the outlet when in the upper position. The invention makes use of the wellknown fact that granular materials have an "angle of repose", commonly in the region of 450, beyond which they cease to flow, and features of the invention are baffles or weirs placed in such a way that the granular material is prevented from flowing from the reservoir into the measuring chamber when the latter is in the upper position, and is prevented from flowing out of the measuring chamber through the outlet when it is in its lower position, in each case by its angle of repose.

One useful application of the invention is illustrated in the attached drawing, Figure 1, which shows the designs of a hand-held device for applying measured quantities of granular materials to plants in pots or in the ground.

In the device shown in Figure 1 granular material is placed in the reservoir, A, which in this particular example consists of an open-ended tube 5 cm wide and 1.1 m long, with a somewhat narrower tube, B, leading from it into two opposed metering chambers, C and D, on the other side of which is a short discharge tube, E, which is about 10 cm long. A baffle, F-G, is placed across and forms part of the two metering chambers.

The reservoir and the discharge tube in this illustration are in the same line and the device may conveniently be he!d so that this iine is inclined at 300 to 400 from the vertical. It can be seen from Figure 1 that the granular material will flow from the reservoir into the lower chamber C, but will cease to flow when the angle of repose is reached at H. At the same time it will not flow into the upper chamber, D, owing to the angle of repost at 1.

it can also be seen that when this device is rotated through 1 800 the chambers will be reversed and the contents of the newly upper chamber will flow out of the discharge tube, E, until material is left only above the baffle, F-G, at its angle of repose J.

Clearly if the baffle F-G, does not reach far enough into the chambers C and D material may be able to flow over the baffle and out, and in this application it is convenient to make the baffle long enough so that the material is retained either at H or at I at whatever angle the device is held (providing it is stationary) between vertical and horizontal.

In operation the hand-held device illustrated in Figure 1 is filled with fertilizer or other granular material and grasped by means of its tubular reservoir. It is then easily rotated through approximately 1800 and back by a simple twist of the wrist, giving a measured amount of fertilizer each time.

It is obvious that the size of the device may be varied to meter out differing quantities of granular material. But the basic device may also be modified so that the quantity metered can be adjusted manually. Several ways of doing this will occur to those skilled in the art. Thus for example the length of the baffle, F-G, may be adjusted, or inserts provide to reduce the metering volume.

Figure 2 illustrates a further method. Here the size of each chamber is adjusted by means of a threaded cap, K, which is screwed in or out to vary the size of the chambers and so the quantity metered. For this application it is clearly convenient that the chambers C and D should be round in cross-section, but for other applications they may be of many other shapes, e.g. square, hexagonal and so forth in cross-section.

A further different shape is shown in the next example, Figure 3, which also illustrates another means of adjusting the metered quantity.

In Figure 3 a tube, L has at one end two pairs of holes in its walls, X1-X2 and Y1-Y2, on either side of a barrier, N, across the tube. The other end of the tube forms the outlet of the device and so is open.

In the intervening space between the tube and the outer case, M, are a number of radial partitions, shown in cross-section in Figure 4.

These partitions divide the intervening space into a number of opposed pairs of segments. The two segments forming each pair are the same size but differ in size from the other pairs. Thus when the tube, L, is rotated pairs of chambers of differing size may be selected by being brought opposite the pairs of holes in the inner tube, L, and when the device is operated in the manner described in the previous examples this variation in the chamber size will enable the metered quantity to be varied.

It will be seen from Figure 3 that the lower chamber will fill through X, and the upper one discharge through Y2 and that these actions will occur and alternately be reversed when the device is operated as previously described.

If it is desired that the granular material should be unable to flow from the reservoir into the outlet when the device is held vertically several possible arrangements will be apparent to those skilled in the art. Thus the wall of the tube, L, may be made much thicker at X1-X2 and Y1-Y2, or baffles projecting into the tube, L, may be fitted just above or just below the pairs of holes. In the example illustrated in Figure 3 a third way is chosen. A groove is made in each partition or segment wall opposite the barrier, N, and a flat ring, P, is inserted into these grooves which acts in exactly the same manner as the baffle G-F in Figure 1.

It will be obvious that while for simplicity the above examples of the invention are described as hand-held devices the required twisting action needed for operating the devices can readily be provided by mechanical means and further that a number of such devices may be mounted and operated together, connected either to a common reservoir or to separate reservoirs.

Claims (6)

Claims

1. A metering device or dispenser for granular fertilizers and other granular materials consisting of opposed chambers connected to a reservoir and an outlet which alternately fill from the reservoir and empty through the outlet as the dispenser is rotated, the device being inclined at an angle of between 100 and 800 so that one chamber in the lower position will fill while the other in the raised position will empty, the granular material being prevented from flowing into the upper chamber or out of the lower chamber by baffles or weirs.

2. such a metering device being hand-held.

3. Such a hand-held metering device being attached to the lower end of a hollow handle acting as a reservoir.

4. Such a metering device being mechanically operated, either singly or as a group of two or more.

5. Such a metering device in which the metered quantity is adjustable by the end-wall of each chamber being movable in or out.

6. Such a metering device in which pairs of chambers of differing size arranged in a ring may be rotated to bring into operation one or other of the pairs of chambers in order to vary the quantity dispensed.