GB2292132A - Screed pump feeder - Google Patents

Abstract

The Apparatus consists of a conduit or pipe 24 through which materials (sand or aggregate) are conveyed by a suction device 22. This entails a combination of agitation and fluid flow movement of the said materials into the screed pump until it is fully loaded or charged. One end of this conduit is placed in or on the pile 30 of material to be conveyed. The discharge end of the conduit may be connected to the screed pump in various ways, including being permanently connected to an inlet in the screed pump vessel in which case a shut off valve means would be required to isolate the delivery conduit during the emptying process of the screed pump. <IMAGE>

Description

BATCH CONVEYING OF MATERIALS SUCH AS FLOOR SCREED MATERIALS This invention relates to apparatus for pneumatically conveying, for example, batches of floor screed material, concrete and other bulk materials such as sand and aggregates, and in particular to the loading of such apparatus.

A known batch feed apparatus comprises a diesel-engined compressor mounted on a wheeled chassis, the chassis also supporting a cylindrical batch holding vessel in which is mounted a rotatable mixer paddle assembly adapted to be driven by the compressor engine.

The cylinder is mounted with its axis horizontal, and the mixer drive shaft is on the axis of the cylinder.

The vessel has a large charging opening in the upper part of the cylindrical side wall, the opening being closable by a lid provided with a suitable air-tight seal to seal the vessel on closure of the lid. A delivery hose is connected to an outlet leading from the lower part of one end of the vessel. A first pneumatic supply line is connected to the upper part of the mixing vessel, and a second pneumatic supply line is connected to the delivery hose connection.

When the known apparatus is to be used with floor screed material, the empty vessel has first to be charged with a batch of sand, cement and water. The requisite quantity of cement would be discharged into the charging opening and sand is shovelled into the charging opening.

A retractable funnel-shaped hopper may be provided over the opening to assist in directing these materials into the charging opening.

When the apparatus is used for laying floor screeds, a very large volume of material may need to be shovelled during the course of a day. It has been proposed to mount a large pivotable charging skip on the chassis, the skip being pivotable by pneumatic rams to a position which allows the contents of the skip to be discharged into the charging opening.

Whilst the pivotable skip does assist in loading of the charging vessel, the skip is relatively bulky and relatively costly.

The present invention provides a less costly means for loading the charging vessel.

Once the known apparatus has been charged with the requisite batch of materials, the hopper is pivotally retracted to permit the lid to be closed. The mixer paddle assembly is rotated for a suitable period to mix the components. Then the first and second supply lines are pressurised. The shape of the paddle assembly, and the pneumatic pressure generated in the mixing vessel urges the material contained in the vessel towards the outlet, to be conveyed by pneumatic pressure through the delivery hose, flow through the delivery hose being assisted if necessary by air supplied through the second supply line.

The known apparatus can also be used for conveying batches of particulate material such as sand or potting compost, for example, in which case it will be appreciated that no actual mixing step will be performed. It should be appreciated that the present invention also relates to loading into a charging vessel of batches of particulate material that do not require mixing.

According to one aspect of the present invention apparatus for pneumatically conveying batches of material from a batch holding vessel is provided with batch loading means adapted to load the batch holding vessel with material and comprising a delivery conduit through which the material is conveyed by fluid flow means.

The fluid flow means preferably comprises a flow inducing device which is commonly termed an 'air mover device'. Such a flow inducing device comprises a generally tubular body provided on the internal walls thereof with one or more slots extending circumferentially of the internal wall, or with a series of circumferentially-spaced orifices, the configuration being arranged such that a relatively small flow of fluid through the slot/s or holes induces a much larger volume of fluid flow through the bore of the device. The configuration required to achieve this effect is generally a venturi shape.

A typical air mover device is the Beck RINGJET(TM) motorless fan produced by O N Beck & Co Ltd of 104 Fox Lane, London N13 4AX.

Such flow inducing devices have the advantage in applications of the present invention that there are no wearable moving parts situated in the air flow.

Such a flow inducing device is conveniently provided with compressed air by the same pneumatic source that is subsequently used for pneumatically delivering the batch of material from the batch holding vessel. Alternatively, an independent pneumatic source could be provided, such as an electrically-driven compressor.

The flow inducing device can be located at any convenient point in the length of the delivery conduit.

That portion of the delivery conduit which is applied to a heap of material to be sucked into the conduit may conveniently take the form of a lance which an operative can hold and re-position as the heap is eaten away.

The lance may be supported on legs or on a suitable stand. Such legs may take the form of prongs which can be stuck into the pile of material.

The discharge end of the delivery conduit may be connected to the batch holding vessel in various ways. When the batch holding vessel is provided with a large inlet opening, then the delivery end of the conduit may simply be directed at said opening, or into a hopper positioned above said opening during loading of the vessel.

Alternatively the discharge end of the delivery conduit may be permanently connected to an inlet to the vessel, in which case shut-off valve means could be required to isolate the delivery conduit during pressurisation of the vessel for expelling a batch from the vessel.

Suitable monitoring means may be provided to record or estimate the quantity of material that has been directed into the vessel, the fluid flow to the fluid flow means being terminated when the appropriate quantity of material for a batch has been delivered to the vessel. The monitoring means may comprise a timer for timing the length of time that the fluid flow means is operative.

According to a second aspect of the invention a method of conveying batches of a material to a remote location comprises supplying a predetermined quantity of material to a batch holding vessel by conveying the material with a fluid flow means from a bulk supply to the batch holding vessel, terminating the supply to the vessel, sealing the vessel, apart from the outlet therefrom, and subjecting the vessel to super-atmospheric pressure so as to discharge the batch of material through an outlet conduit leading from the vessel.

Embodiments of the invention will now be briefly described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic side elevation, partly in vertical section, of a batch conveying unit in accordance with the invention, Figure 2 is a schematic longitudinal cross-section of an air mover device as used in the unit of Figure 1, and Figure 3 is a view similar to Figure 1 of a modified batch loading means in accordance with the invention.

With reference to Figure 1, a diesel-driven compressor 1 and a cylindrical batch holding vessel 2 are mounted on a chassis 3 supported on a pair of wheels 4. The vessel 2 has a wide charging opening 5 closeable by a pivoted lid 6 carrying a seal, not shown, to seal the opening 5 against atmosphere when it is required to pressurise the vessel 1. A mechanical agitator assembly 7 is adapted to be driven by a drive shaft 8 by the compressor motor, preferably through a clutch. The blades 10 of the agitator assembly 7 are configured to urge the material in the vessel 1 towards an outlet 11 when the shaft 8 is rotated in the appropriate direction.

A first pneumatic supply line 12 containing an on/off valve 13 is connected to the upper part of the vessel 1 for pressurising the vessel, and an optional second pneumatic supply line 14 containing an on/off valve 15 is connected to an outlet adaptor 16 connected between outlet 11 and a supply hose 17 which conveys material, such a floor screed material, to a remote location, which can be one or more storeys above ground level 18.

What has been described so far is essentially a conventional batch mixer and pneumatic supply unit.

The inventive batch loading means comprises a fluid supply conduit 18 in the form of a tubular lance 19 with carrying handle 20 and integral air mover device 22, a flexible hose 21 leading from the lance 19 to a discharge pipe 24. The discharge pipe 24 is suitably mounted to extend into a frusto-conical hopper 25 which is capable of being positioned over the opening 5 but is swingable to a retracted position to enable the lid 6 to be brought into the closed condition.

Figure 3 shows a modified arrangement in which the discharge pipe 24 is pivotally mounted at 30 on a fixed bracket 31 and is counterbalanced by a weight 32.

In the operative position of the hopper 25, as shown in Figure 1, the pipe 24 is directed into the interior of the vessel 1 so that material blown from pipe 24 is dispensed into the vessel 1.

In a further alternative arrangement, not shown, the pipe 24 is permanently connected to an independent inlet to the vessel, the pipe 24 then incorporating a shut-off valve for isolating pipe 24 when it is desired to pressurise the vessel 1.

As shown in Figure 2, the air mover device is generally tubular. In use air is forced through an annular slot 27 to induce a flow of air of much larger volume through the bore of the device.

The operation of the batch conveying unit will now be described with reference to its use with floor screed.

In order to load the vessel 1, the requisite number of bags of cement are emptied into the hopper 25 and then a quantity of water is dispensed into the vessel 1.

The air supply to the air mover, conveniently fed from the compressor 1 is then turned on and the lance 19 is stuck into a pile 30 of sand or aggregate where it is supported by legs or prongs 19'.

The suction created by the induced flow of air through the bore of air mover 22 results in sand or aggregate being sucked from the pile 30 to be blown through pipe 24 into the vessel 1.

When the requisite amount of sand or aggregate has been fed into the vessel 1, the hopper 25 is swung aside, and the lid 6 is closed to seal the vessel 1.

The agitator assembly 7 is rotated for a suitable time to mix the cement and sand to form the screed material. Then the valves 13 and 15 are opened by predetermined amounts, and the rotation of the agitator assembly 7, in conjunction with the pressure in vessel 1, directs the screed to hose 17 for supply to a delivery point.

Injection of air from supply line 14 into the outlet adaptor 16 can assist in conveying the screed on cushions of air through hose 17.

Claims (1)

1. THE CLAIMS

   THE INVENTION SHALL BE KNOWN AS A "SCREED PUMP FEEDER" This invention is a means of charging or loading a screed pump with sand or aggregate to be conveyed by fluid flow, the apparatus can or may be assisted by compressed air from the screed pump itself.