CA2366273C - Apparatus and method for storage of wet particulate material - Google Patents

Abstract

A heatable storage system for wet, particulate material such as sand and gravel, comprising a metal container having at least one side defining a chamber for holding the material; heating means adjacent the side to provide heat to the material; to prevent substantial freezing of the side and the material; and agitation and metering means within the chamber to effect agitation of a least a portion of the material and metered dispensation of the material from the chamber.

Description

I

APPARATUS AND METHOD FOR STORAGE OF
WET PARTICULATE MATERIAL

FIELD OF THE INVENTION
This invention relates to a system for the storage of wet particulate material, such as sand and gravel, having heating means and material delivery means, and particularly to said system being adapted to be transportable by a wheeled vehicle.

BACKGROUND TO THE INVENTION

Sand, gravel and like aggregates of use in the construction industry on-site is, at present, dumped from trucks on top of an unprotected area, such as a culvert.
The aggregate materials usually are wet or damp when delivered from a quarry and, when left exposed to the elements under winter conditions, the water contained therewith freezes. This often makes it difficult for the aggregate to be manually shoveled, metered and satisfactorily mixed in a mechanical mixer. The industry, generally, relies on heating the piled material by propane or wood burning in the culvert to prevent freezing or loosen frozen material. This, however, is an expensive preventive and/or remedial way of providing acceptable, workable aggregates.
Such frozen material is also formed if the container carrying the material is transported under adverse weather conditions.
Further, the accurate dispensation of the material from the container is also compromised when the aggregate materials contain ice.
There is, therefore, a need for providing workable, particulate material for use in the construction industry, on demand in a desired, reproducible amount.

2 SUMMARY OF THE INVENTION

It is an object of the present invention to provide a delivery and storage system for wet, aggregate construction materials to and at a construction site that prevents the freezing of the wet materials.
Accordingly, the invention provides a heatable delivery system for wet, particulate material, comprising a metal container having at least one side defining a chamber for holding said material; heating means adjacent said side to provide heat to said side and said material, and adapted to receive an energy source to prevent substantial freezing of said material, and agitation and metering means within said chamber to effect agitation of a least a portion of said material and metered dispensation of said material from said chamber.
By the term "freezing" in relation to the wet material is meant the freezing of the water associated with the particulate matter.
Wheeled vehicle includes trucks, rail cars and the like.
Preferably, the container is of a rectangularly-shaped, open-topped box formed of a metal, such as for example steel, suitable for holding significant amounts, e.g. form 1 - 20 cubic metres, or greater in the case of rail cars, of heavy aggregates, such as sand, gravel and the like. Typical dimensions of a container of use in the .invention are 7 metres long, 3 metres wide and I metre high, formed of 0.5 cm thick steel.
In an alternative embodiment, the container may be a single sided double semi-cone shaped walled barrel adapted to be retained on a truck or like vehicle.
The energy source preferably comprises electrical heating means preferably formed of suitable lengths of heating cable suitable for freeze protection suitably disposed adjacent the metal bottom and/or sides, either inside or outside of the container. The cable conductor is most preferably embraced in a braided metal sheath which provides a good grounding capability and good physical protection. The heating cable preferably has a high temperature rating which provides good "wearing"
qualities at elevated temperatures. A power output rating of 12 - 30 watts/metre may provide continuous operation up to a maximum temperature of up to 250 C.
The aforesaid heating cable is to be disposed more often on the outside of the container than within the container. An alternative electrical heating means for use

3 adjacent the inner walls and bottom is an electrical resistance heating cable buried in a sand bed at the bottom of the container or along and up the inner sides which is buried in the sand or aggregate product shipped and/or stored on site. Most preferably, the cable is suitably affixed to the sides and/or bottom of the container by any suitable means such as by retaining clips or the like. Suitable protection from physical damage caused by shovels or scoops, manually or mechanically operated may be provided by wire retaining mesh disposed adjacent some distance from the cable.
The cable is adapted with suitable junction boxes, plugs, sockets or the like to receive electrical current from the vehicle during transportation or from a generator or main supply.
An alternative form of heating as an energy source is provided by hot water passing through an array or network of metal or plastic pipes or tubes, generally of 1- 2 cm in diameter, fed from a boiler or electrical heating water tank, which the network of pipes may be laid out as for the thermal cable network hereinbefore described.
In an alternative, but less favoured embodiment the hot water circulation pipes may be also embedded in a 2" bed of sand at the base of the container. The piping network may also be provided with high or low capacity manifolds to service form 20 -200 m lengths of pipes, a circulating pump, temperature sensors, valves and the like.
The container metal wall temperature may be maintained at a temperature in relation to the ambient temperature, such that for example, a 1 C increase in the wall temperature my be required for each 5 C drop in the ambient temperature, which may also be related to the wind chill factor.
Thus, a system as hereinbefore described is provided wherein said heating means comprises hot fluid conduit heating means.
By the term "fluid" is meant a gas or liquid. While water is the preferred fluid, a supply of hot exhaust gases of a combustion engine passing through the pipe network may optionally be used.
The metering means, such as for example, an elongated screw threaded member such as an auger is suitably disposed and retained in the container to not only provide a metered amount of particulate matter on demand either, continuously, or in specified quanta, but, optionally, as an agitation means for disturbing the particulate material

4 during storage to assist in heat transfer through the whole or a portion of the material mass.
Alternative metering means may be provided, for example, by a continuous rotary chain holding a plurality of scoops or ribbed conveyer belt. The auger and scoops may deliver the metered aggregate into a suitable heatable container for storage or directly into a mixer.
The container in preferred embodiments has means by which it is liftable onto a track by a crane, sling, fork lift vehicle or the like. A raised base to enable a pair of forks of a fork-lift truck to get beneath the container is most preferred.
Alternatively, apertures or eye-bolts in the sides of the container may be so shaped as to operably receive hooks, bolts or the like.
The system according to the invention may be limited to use of the container as a re-fillable dump-box or silo not intended to be intermittently being delivered with material and transported for re-filling.
The aforesaid system is of use, for example, in maintaining temperatures of materials above freezing, particularly construction materials for use during the winter related to masonry, precast manufacturers, refuse and sanitation companies such that the material can be readily and, optionally, accurately dumped when ready. Ready mix companies normally runs steam pipes underneath products so that they can be used when needed. The invention provides a heated storage upon enclosing for winter storage and during the summer with no contamination of product.

BRIEF DESCRIPTION OF THE DRAWINGS
In order that the invention may be better understood preferred embodiments will now be described by way of example only with reference to the accompanying drawings wherein Fig. 1 is a diagrammatic perspective view of a system according to the invention comprising electrical resistance heating;
Fig. 2 is a diagrammatic perspective view of a system according to the invention comprising hot water conduit heating; and wherein the same numeral denotes like parts.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to Fig. 1, this shows generally as 10 a system according to the

5 invention having a steel container 12 fitted with electric conduit 14 and an attached auger 16.
Container 12 is in the form of an inverted trapezium having four sides 18 defining a chamber 20 for storing sand particulate matter 22. The upper open top 24 of the trapezium is covered with a protective screen 26. Container 12 is filled with the wet sand 22 in the embodiment shown. A tarpaulin (not shown) may be used to assist in rain "run-off'.
Adjacent the four sides 18 of container 12 in close abutment is attached a length of electrical heating cable 14, which provides suitable heating at a desired rate of between 12 - 30 watts/metre. Heating cable 14 is preferably fastened between the cross member supports (not shown) which traverse container 12 at its undersides at generally 0.3 m centres. An average of 6 wires spaced apart by 5 cm one from another between the supports provide sufficient heating. Fiberglass or like insulation within a plywood covering provides some protection from physical damage.
Auger 16 is suitably disposed within chamber 20 and has its upper end 30 connected to electrically driven hydraulic pump 32 connectable by conduit 36 to AC
power supply (not shown). The auger is, preferably, about 15 - 20 cm in diameter, and tilted within chamber 20 with its length running parallel to the inverted apex corner of contoured box 12 and is shorter, by a small margin than the full length of box 12 to insure that all sand is removed as required. A non-metered system vs. a metered one may be chosen depending on the requirements of the user, to calculate the amount of material being extracted for use. The auger brings up sand 22 and optionally pours it into a chute, bobcat, wheel barrow, conveyor belt or similar transportation means (not shown) which carries the sand into a mixer for blending.
System 10 has planar metal sides 33 which embrace container 12 and also provided storage space 34 beneath container 12. This space may be used to cover a hot water or propane burner, control boxes, circulation pumps and the like, shown collectively as 38, when the system uses hot water as shown in Fig. 2.

6 In an alternative embodiment, the system may be `open" around the container 12 while having four legs, one at each corner.
The system may be readily adapted to be picked up and set on a wheeled-vehicle, such as a truck, for transportation from a quarry or like material source to a construction site. A base 40 raised off the ground by feet 42 enables the forks of a forklift vehicle (not shown) to convey the system onto the bed of a vehicle for transportation.
Although this disclosure has described and illustrated certain preferred embodiments of the invention, it is to be understood that the invention is not restricted to those particular embodiments. Rather, the invention includes all embodiments which are functional or mechanical equivalence of the specific embodiments and features that have been described and illustrated.

Claims (8)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A heatable storage system for wet, particulate material, comprising a metal container having at least one side defining a chamber for holding said material;
electrical conduit resistance heating means disposed within or outside of said chamber adjacent said side to heat said side and said material to prevent substantial freezing of said material; and agitation and metering means within said chamber to effect agitation of at least a portion of said material and metered dispensation of said material from said chamber.

2. A system as defined in claim 1 wherein said container is of a rectangular-shaped form having an open top, four sides and a base defining said chamber.

3. A system as defined in claim 1 wherein said container has sides defining an open topped inverted trapezium.

4. A system as defined in claim 1 wherein said container has a single side having a portion defining a cone.

5. A system as defined in any one of claims 1 to 4 wherein said heating means comprises said electrical conduit means disposed within said chamber.

6. A system as defined in any one of claims 1 to 4 wherein said heating means comprises said electrical conduit means outside of said chamber.

7. A system as defined in any one of claims 1 to 6 wherein said agitation and metering means comprises an elongate screw-threaded member.

8. A system as defined in any one of claims 1 to 7 adapted to be transportable by a wheeled vehicle.