GB2045729A - A discharge device - Google Patents

Abstract

A discharge device (9) for attachment as a hood to the mouth of a drum (1) or like container for discharge of material contents of the drum, after inversion thereof, by a rotor through an outlet from the hood; wherein the hood is a pan (16) of shallow, substantially cylindrical shape with a flanged mouth (17) to fit over the mouth of a drum, a discharge outlet (20) is located in the base of the pan at the periphery (22) thereof and a rotary assembly with a blade or blades (25) is provided to operate over the pan base (19) and across the discharge outlet, the blade or blades being shaped to stir or lift material to be swept around and towards the discharge outlet. Preferably, a wall (21) of an extension of the discharge outlet (20) is a continuation of a side wall (22) of the pan. Also, the blade or at least one of the blades (25) may be provided with a base contacting sealing strip (26) so that the rotary assembly can sweep the pan base across the discharge outlet. <IMAGE>

Description

SPECIFICATION A discharge device This invention relates discharge devices for discharging materials from drums or like transport containers. The particular, but not exclusive, application is to the discharge of granulated, pasty or powdered materials which do not flow freely by gravity alone or which have a tendency to bridge; that is materials not possessing the rheological properties of freely flowing fluids.

In many branches of manufacture, process requirements demand the discharge of granular matter, powders or pastes, frequently very finely ground powders which have a tendency to surface adhesion, through an aperture and into another vessel for mixing or other purposes. It is well known that if the discharge takes place through a conical funnel, difficulties are encountered in this process due to a tendency of powders to depart from a fluid type motion. Even when the container from which the powders are discharged is subjected to vibratory action these difficulties are not fully eliminated. The powder forms bridges or arches and its motion may be totally arrested.

Unless the funnel cone has a very small apex angle and thereby becomes very long and inconvenient in use, bridging of the powder is aggravated by the conical shape of the discharging vessel bottom.

It is an object of the present invention to overcome the above stated disadvantages by replacing the funnel between the cylindrical portion of the drum and the discharge aperture by a novel discharge device which can operate via a relatively small opening in the flat base of a substantially cylindrical pan; the discharge of the powder or other material being urged by the stirring action of a mechanically driven rotating assembly.

According to the present invention, a discharge device for attachment as a hood to the mouth of a drum or like container for discharge of material contents of the drum, after inversion thereof, by a rotor through an outlet from the hood; is characterised in that the hood is a pan of shallow substantially cylindrical shape with a flanged mouth to fit over the mouth of a drum, a discharge outlet is located in the base of the pan at the periphery thereof and a rotary assembly with a blade or blades is provided to operate over the pan base and across the discharge outlet, the blade or blades being shaped to stir or lift material to be swept around and towards the discharge outlet.

In one embodiment of the invention, a wall of an extension of the discharge outlet is a continuation of a side wall of the pan.

In another embodiment of the invention, the blade or at least one of the blades is provided with a base contacting sealing strip so that the rotary assembly can sweep the pan base across the discharge outlet.

The above and other features of the invention are illustrated, by way of example, in the drawings, wherein: Figure 1 is a side, sectional elevation of a discharge device in accordance with the invention attached to the cradle of a drum hoist; Figure 2 is an end elevation of the discharge device and cradle of Fig. 1; and Figure 3 is a plan view of the discharge device and cradle of Fig. 1, but with the cradle foot removed.

A drum 1 (indicated by broken line in Fig.

1) is held inverted in a cradle having two arms 3, 4 extending angularly outwardly from each side of a central, vertical, hollow spine 5 and part way around the periphery of the drum 1. Opposed pairs of arms 3 and 4 respectively terminate at either end of a diameter of the drum. Clearly, a different size cradle is required for different sizes of drum.

At each side, the arm ends 6 are attached to a vertical member 7 to the bottom ends 8 of which a discharge device 9 is attached.

A cradle foot 10 is carried by a screw pillar 11 running vertically down through the cradle spine 5 to a screw clamping mechanism 1 2.

The spine has, approximately at its midlength, a mounting 1 3 for the arm (not shown) of a hoist (not shown) that, jointly, enable the cradle to be lifted vertically, rotated in a vertical plane about the axis of the mounting 1 3 and slewed in a horizontal plane about the turning axis of the hoist. A flexible strap 14 (indicated by broken line in Fig. 1) can be attached to lugs 1 5 on the vertical cradle members 7 to hold a drum in the cradle.

The discharge device 9 is shown to comprise a shallow cylindrical pan 16 with a radially outwardly flanged mouth 17, having a ring seal 18, that can be clamped to the open mouth of a drum by the action of the clamping mechanism 1 2 on the screw pillar 11 to draw the cradle foot 10 towards the discharge device 9.

The internal diameter of the pan 1 6 is, preferably, at least equal to the internal diameter of the drum to be discharged, so that a peripheral ledge is not formed at the junction of the drum and pan mouths against which material could lodge or jam. Alternaiively, the pan walls might flare slightly outwardly down from the pan mouth.

The pan 1 6 has a flat base 1 9 with a discharge outlet 20 therein and having a short cylindrical extension, the side wall 21 of the discharge extension being at one tangential point a continuation of the pan side wall 22.

That is, the discharge outlet is at the internal periphery of the pan 1 6. The bottom of the discharge cylinder is flanged to receive a controllable iris discharge valve, such as a "MUCON" (Trade Mark) valve.

A shaft 23 is journalled to pass through the centre of the pan base 1 9. The innder end of the shaft 23 terminates in a boss 24 carrying a pair of radially extending blades 25. Each blade 25 is mounted in the boss 24 at an angle so that, an rotation of the blade, material in the discharge device is stirred or lifted upwards and around the pan base, that is in the oposite direction to a conventional discharge auger.

The blades 25 may have a streamlined profile and may have many variatios of number, chord, thickness and "angle of attack" depending on the material to be discharged.

A sealing strip 26, which may be a continuous strip of elastomer or a brush, is mounted below each blade to sweep the pan base 1 9 and across the discharge outlet 20 on rotation of the blade assembly.

The outer end of the shaft 23 carries a pulley 27 to which a drive belt 28 runs from an air operated motor 29 mounted on the cradle.

In an un-illustrated alternative, a geared, variable speed electric motor may be used to rotate the rotary assembly of shaft 23, boss 24 and blades 25; the sealing strips 26 being optional.

The height of the pan 1 6 determines, along with other variables including the characteristics of the material to be discharged, the pitch and number of blades and the rotational speed of the blade assembly, the discharge rate of the device; the pan should be as shallow as possible. Obviously, sufficient clearance has to be given for the rotary assembly but, for some applications where the drum has a lining bag of thin plastics film, the edge of which is trapped between the drum mouth and the discharge device's mouth flange 17, additional clearance or pan depth has to be provided to prevent the lining bag from dropping down and fouling the rotary assembly.

The rotary assembly is capable of many special embodiments for related purpose. Its basic function is to make granular, powdered or deformable substances which resemble fluids but are not freely flowing (or possess rheological properties very different from those of freely flowing fluids) behave in a manner more similar to such freely flowing fluids. For example, certain thick non-Newtonian liquids and even dough-like mixtures can be discharged with the help of the stirring action of the rotating blades in a manner similar to freely flowing fluids.

For some applications, more than one discharge opening may be provided in the pan base.

Claims (6)

1. A discharge device for attachment as a hood to the mouth of a drum or like container for discharge of material contents of the drum, after inversion thereof, by a rotor through an outlet from the hood; wherein the hood is a pan of shallow, substantially cylindrical shape with a flanged mouth to fit over the mouth of a drum, a discharge outlet is located in the base of the pan at the periphery thereof and a rotary assembly with a blade or blades is provided to operate over the pan base and across the discharge outlet, the blade or blades being shaped to stir or lift material to be swept around and towards the discharge outlet.

2. A device as claimed in claim 1, wherein a wall of an extension of the discharge outlet is a continuation of a side wall of the pan.

3. A device as claimed in claim 1 or claim 2, wherein the blade or at least one of the blades is provided with a base contacting sealing strip so that the rotary assembly can sweep the pan base across the discharge outlet.

4. A device as claimed in nay of claims 1 to 3, wherein the discharge device is attached to a cradle shaped to receive a drum and having means to clamp the mouth of the drum against the mouth of the discharge device.

5. A device as claimed in claim 4, wherein the cradle has a mounting about which it can be rotated in a vertical plane.

6. A discharge device substantially as described with reference to or as shown by the drawings.