GB2176175A - Inducing flow of granular or like material within a container - Google Patents

Abstract

A device for inducing flow of granular or like material within a container (23) such as a hopper, silo or bunker comprises a gas discharge opening (19) into the container adjacent an interior wall thereof, means (11) for discharging gas intermittently through the opening into the container and a defector (24) arranged over the opening having a face inclined to the axis of the opening and to the surface of the container such as to deflect the discharge of gas downward as shown by the arrow (25) and to prevent material which is flowing downward in the container from entering the opening. <IMAGE>

Description

SPECIFICATION Device for inducing flow of granular or like material The invention relates to devices for inducing flow of granular or like material within containers such as hoppers, silos or bunkers.

Such devices known as blasters are described for example in UK Patent Specifications 1,426,035 and 1,454,261 and in US Patent Specification 4,496,076.

These devices incorporate a reservoir into which air is supplied from a compressed air source, a discharge pipe communicating with an opening into a container and a fast acting valve which can be opened suddenly to provide an explosive discharge of air into the interior of the container. The sudden discharge tends to aerate material in the container to assist it to flow but also and possibly more importantly, provides an explosive force which tends to loosen material and start it to flow. Other gases besides air may be used when the material in the container should not be exposed to air.

Blasters are used in connection with very fine material such as powders and fine granuiar material but are also used in connection with materials such as coal, which have much larger particle sizes.

An object of the invention is to provide an improved arrangement for the discharge opening of such an installation into a container.

According to one aspect of the invention a device for inducing flow of granular or like material within a container such as a hopper, silo or bunker comprises a gas discharge opening into the container adjacent an interior wall thereof, means for discharging gas intermittently through the opening into the container and a deflector arranged over the opening having a face inclined to the axis of the opening and to the surface of the container such as to deflect the discharge of gas downward and to prevent material which is flowing downward in the containerfrom entering the opening.

Preferably the deflector is in the form of a canopy having an inclined deflector plate substantially flush with the container surface at its upper end and spaced from said surface at its lower end to provide a downwardly directed discharge passage and having side plates to close off space between the sides of the deflector plate and said surface. The device may have a backing plate for mounting substantially flush with said surface and carrying the deflector plate and side plates.

For use in a container having a concrete wall, the device may further comprise a mounting structure arranged to be set in the concrete with a mounting face substantially flush with said surface and mounting means for securing the backing plate to the mounting structure. The mounting structure may be in the form of a box through which a gas discharge pipe providing said opening passes.

The invention also extends to a container such as a hopper, silo or bunker incorporating at least one device for inducing flow of granular or like material as defined above.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic representation of a blaster for providing an intermittent discharge of gas; Figure2 is a diagrammatic representation of a container in the form of a hopper incorporating an installation in accordance with the invention.

Figure 3 is a side elevation of a discharge arrangement into the container; Figure 4 is an end view in the direction of Arrow IV of Figure 3; and Figure 5 is a plan view of the arrangement shown in Figures 3 and 4.

Figure 1 illustrates a biaster 11. The blaster comprises a pressure vessel or reservoir 12 which in use stores air art a pressure of the order of 6 to 10 atmospheres. The air is supplied through a compressed air line 13 to a solenoid operated valve 14 arranged to connect a transfer pipe 15 alternately with the pressure supply 13 or an atmospheric vent 16. The transfer pipe 15 supplies air under pressure to a main vlave 17.

Valve 17 incorporates main ports 18 by which the interior of the reservoir 12 can be exhausted freely to a main outlet 19. A piston 21 controls opening and closing of the valve 17. When air is supplied to the valve 17 behind piston 21 via transfer pipe 15, the pressure of this air moves the piston to the right as shown to close the valve 17. From the interior of main valve 17 the air can flow through a check valve 22 into the interior of the reservoir to build up pressure therein.

At any time after the reservoir has been pressurised adequately, the solenoid valve 14 may be operated with the result that the region behind piston 21 is vented to atmosphere through vent 16.

Check valve 22 prevents discharge of the contents of the reservoir through this route to atmosphere.

Piston 18 incorporates means such as a stepped diameter responsive to pressure in the reservoir whereby it is then retracted to open the ports 18.

This retraction is very fast because immediately upon initial opening, pressure from the reservoir is applied to the whole of the end face of the piston. On opening valve 17, air is discharged explosively from the reservoir 12 through ports 18 and the outlet 19.

Further details of a blaster unit are not necessary for an understanding of the present invention but may be obtained from the prior art referred to above.

Figure 2 is a simplified diagrammatic illustration of a blaster incorporated in a hopper for inducing flow of material therein. The blaster 11 has its outlet 19 connected to the interior of a hopper 23 at a position where there is a possibility of material becoming lodged in the hopper. A deflector canopy 24 which will be described in greater detail with reference to Figures 3 to 5 is arranged over the opening from the blaster into the hopper in order to deflect air in a downward direction as indicated by Arrow 25 and also to prevent flow of material within the hopper through the outlet 19 into the blaster.

Figure 3 to 5 show details of the discharge arrangement into the container. This particular example is concerned with an arrangement for use in a concrete container but the invention can be applied in a simplified form to steel walled containers as will be explained subsequently.

The interior surface of the concrete bunker is represented by the line 26. A mounting structure 27 in the form of a box is set into the concrete with a front face 28 flush with the interior surface of the hopper. The mounting structure or box 27 comprises a rectangular rear plate 29, a corresponding rectan gularfront plate 31, side plates 32 and 33 and top and bottom plates 34 and 35. All of these plates are welded together to form a box like structure. Rear plate 29 incorporates a circular opening to which an air discharge pipe 36 is connected by a spigot 37 and a series of fasteners 38. Pipe 36 is connected to the outlet 19 of the blaster of Figure 1 as illustrated in Figure 2. Pipe 36 extends through the box through a corresponding central opening in the front plate 31 to terminate at a gas discharge opening 37 leading to the interior of the container.The deflector canopy 24 is arranged over the discharge opening 37. The deflector canopy comprises a rectangular backing plate 42 which is slightly smaller than the front plate 31 and in practice is secured thereto by a series of fixing elements such the bolt assembly 43 shown.

The backing plate 42 has a central opening through which the pipe 36 extends so that its opening 37 projects very slightly beyond the backing plate. A deflector canopy comprising a generally triangular deflector plate 44 and two side plates 45 and 46 is positioned over the opening 37. The deflector plate 44 itself is inclined at an angle of 15 (in this example) to the backing plate 42 and thus at this angle to the surface 26 of the container. At its upper end, the deflector plate is welded to the backing plate and thus is substantially flush with the backing plate and with the surface 26. The triangular side plates 45 and 46 close off the space between the sides of the deflector plate and the backing plate 42.

The side plate and deflector plate are welded together and to the backing plate. Two support bars 46 are welded in position and help to support the lower end of the deflector plate on the backing plate.

In use, when air is upplied in an intermittent explosive mannerfrom the blaster th rough the pipe 36, it is deflected downward by the deflector plate 44 and is thus expelled in a downward direction substantially along the face 26 into the interior of the hopper. The device should be fitted in the hopper immediately above a region in which material is likely to become lodged and this burst of air in a downward direction is particularly helpful in dislodging material in this way. Becuase of the explosive nature of the discharge of air, it does also tend to disturb material within other regions of the hopper and generally assist in the flow of air through the hopper.

As material flows downward over the deflector canopy during discharge, the deflector canopy serves the purpose of shielding the opening 37 from the material so that the material does not pass through the opening into the blaster. Abrasive material in a blaster can reduce its life. Also, an opening such as 37 without a deflector plate could have material jammed with it. This is particularly true with large material such as coal.

Over a substantial period of use with abrasive materials, there is a tendency for the canopy to wear out or become damaged so there may be a need to remove and replace it. For this reason it is preferred to emply renewable blind fixings between the backing plate 42 and the front plate 31 of the box so that the fixings can be replaced easily. Nut and bolt assembly 43 is only shown by way of example as a simplified form of fixing. Fixed studs projecting from the plate 31 would not in general be suitable due to the likelihood of damage and the difficulty of replacement.

When the device is used in a hopper or other container having a steel wall as opposed to a concrete wall, the mounting structure or box 27 may be omitted and the backing plate 42 may be mounted directly to the wall of the container.

Claims (7)

1. A device for inducing flow of granular or like material within a container comprising a gas discharge opening into the container adjacent an interior wall thereof, means for discharging gas intermittently through the opening into the container and a deflector arranged over the opening having a face inclined to the axis of the opening and to the surface of the container such as to deflect the discharge of gas downward and to prevent material which is flowing downward in the containerfrom entering the opening.

2. A device as claimed in Claim 1 wherein the deflector is in the form of a canopy having an inclined deflector plate substantially flush with the container surface at its upper end and spaced from said surface at its lower end to provide a downwardly directed discharge passage and having side plates to close off space between the sides of the deflector plate and said surface.

3. A device as claimed in claim 2 having a backing plate for mounting substantially flush with said surface and carrying the deflector plate and side plates.

4. A device as claimed in Claim 3 for use in a container having a concrete wall, further comprising a mounting structure arranged to be set in the concrete with a mounting face substantially flush with said surface and mounting means for securing the backing plate to the mounting structure.

5. A device as claimed in Claim 4 wherein the mounting structure is in the form of a box through which a gas discharge pipe providing said opening passes.

6. A device for inducing flow of granular or like material within a container substantially as described with reference to and as illustrated by Figures 1 to 5 of the accompanying drawings.

7. A container such as a hopper, silo or bunker incorporating at least one device for inducing flow of granular or like material as claimed in any of the preceding claims.