GB2206059A

GB2206059A - Apparatus for producing cementitious material

Info

Publication number: GB2206059A
Application number: GB08703318A
Authority: GB
Inventors: William Thomas Williams
Original assignee: WORCESTER Ltd
Current assignee: WORCESTER Ltd
Priority date: 1987-02-13
Filing date: 1987-02-13
Publication date: 1988-12-29
Anticipated expiration: 2007-02-13
Also published as: HU199905B; ZA881026B; HUT46749A; ZA88969B; GB8703318D0; GB2206059B; EP0279615A1

Description

2206059 1 - 1 "APPARATUS FOR PRODUCING AERATED CEMENTITIOUS MATERIAL" This

invention relates to apparatus for producing aerated cementitious material.

Apparatus according to the present invention feeds and mixes cement with water and a foaming agent, with or without fillers such as sand and pulverised fuel ash, to produce aerated cementitious material.

3_ Without f i--L'Lers Lhe is;---,a.-Le for filling spaces in double walls of buildings because of its heat insulation, fireproof and vermin proof properties. It can also be used for covering roofs.

The addition of fillers is desirable for making bricks, beams, floors, road paving and swimming pools.

1 r_ In order to produce continuously aerated cement itious material of high and predictable quality it is essential that the proportions of the different ingredients are accurately controlled, and that these ingredients are thoroughly mixed.

The present invention is apparatus for pro ducing aerated cementitious material, including a first hopper for cement, means for conveying cement from the first hopper to a mixing means, a second hopper for a filler material and means for conveying filler material from the second hopper to the mixing means, said conveying - 2 means including a first screw conveyor in the first hopper and a plurality of screw conveyors in the second hopper, each of said screw conveyors having its respective constant speed drive means, and said second hopper having a sidewall which is inclined inwardly to overhang the adjacent screw conveyor An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:- Fig. 1 is a side elevation of apparatus according to the present invention for making aerated cementitious material; Fig. 2 is a rear end elevation of the appara-."s of Fig,. 1; Fig. 3 is a front end elevation of the apparatus of Fig. 1; Fig. 4 is a plan view of the apparatus; and Fig. 5 is a side view of the mixing chamber of the apparatus on an enlarged scale.

Referring now to the drawings, apparatus for making aerated cementitious material comprises a chassis 10 having road wheels 11 arranged to serve as a trailer to a road vehicle. The road wheels 11 are retractable to enable the chassis 10 to be lowered p D to the ground of materials The cement, and a filler such as The for stability and to facilitate supply to the apparatus when in use on site. apparatus includes a first hopper 12 for larger second hopper 13 for sand or other pulverised uel ash for example.

cement is metered through a circular aperture 14 in the front wall of the hopper assembly by means of a round rod helix conveyor 18 whilst the filler is metered through circular apertures 15, 16 and 17 in the front wall by means of respective round rod helix conveyors 19. The helices of the conveyors 18 and 19 are mounted for rotation on shafts whose diameters decrease towards the apertures 114, 15, 16 and 17. This construction ensures a uniform flow of material over the length of the hoppers into the helices along the lengths thereof, and significantly reduces torque load. The common wall 21 between the hoppers 12 and 13 is inclined into the hopper 13. In the embodiment illustrated the wall 21 is at right angles to the inclined base 22 of the hopper to provide an acute angle to the verticaland overhang the adjacent conveyor 19 allowing it to be used on its own without cavitation. The conveyors 18 and 19 have individual constant speed drive motors 24, 25, 26 and 27.

Accurate control of the flow of material 1 4 through the apertures 14 to 17 is obtained by metering valves in the form of respective conical plugs 29, 301 31 and 32 which can be advanced into the apertures 145 15, 16 and 17 respectively or retracted therefrom, to a desired extent by individual control levers (not shown). The plugs have axial bores to accommodate the ends of the conveyor shafts therein.

Generally it will be sufficient for each p lug 29 to 32 to be set in one of three positions giving ful--l flow, half flow and no flow respectively enabling most commonly required mixes of cement to filler such as 1:1, 1:2, 1:3, or 1:4 to be obtained by suitable selection of the plug positions and proper control of the number of conveyors 19 in operation.

Additional control can be had by provision of bulkhead s 34 and 35 slidable over the respective lengths of the hoppers 12 and 13, thereby varying the effective lengths of the hoppers and the amount of the filler and cement entering the helices of the conveyors.

Material s the aDertures 14, transverse endless delivered by the conveyors through 15, 16 and 17 are delivered to a band conveyor 36 which carries them to a mixing chamber 37.

Also delivered to the mixing chamber 37 by L independent pumps 45 and 47 are water from a tank 39 and liquid foaming agent from a tank 38 and a foam injection gun 40, which provides 20 micron indpendent air cells to the chamber 37.

The various ingredients are conveyed from the chamber 37 and thoroughly mixed in an upwardly inclined cylindrical mixing chamber 41 comprised by a flexible tube 42 (typically rubber or P.V.C.) supported within a steel cage 43.

A shaft 44 driven by a motor 49 extends axially through the chamber 41 and carries a short section of two-start full flight helical conveying screw 46 at its lower end for rapid removal of material from the chamber 37, thus to prevent any damming of the incoming materials. Following the screw 46 is an extended length of ribbon helix 48 connected to the shaft 44 by struts 50.

Axially extending bars 52 are provided at intervals between struts 50 to carry freely rotatable round rod helices 53 which contact the inner periphery of the chamber 41. Regardless of the amount of material input the mixing chamber 41- has to be filled completely before any delivery occurs at the outfall.

This arrangement provides for a thorough mixing of the ingredients, regardless of throughput, as they pass upwardly through the chamber 41 for delivery to a placing pump 55.

Throughput may be as little as 0.05m3/min for spray applications and as high as 0.3M3/min for bulk pouring, for example.

The Pump 55 ient delivery tube 54 tiallv horizontally. switch to facilitate is a peristaltic pump whose resiland motor 56 are disposed substanThe motor 56 includes a reversing the replacement of delivery tubes and in the case of blockage, reversing the rotation clears any stoppage. The roller carriage 57 is readily removed for the removal of any material allowed to solidify impeding the rollers.

The electric drive motors in the machine are constant speed motors and the startup sequence is pump motor 56, mixer motor 40, solution pump 47, compressor 60 for supplying air to the foam gun 40, water pump 55, conveyor 30 and the selected combination of conveyors 18 and 19.

Water, solution and air are metered through flow controls to chamber 37 in accordance with the -5y contrel and dens-itv desired.

A control panel contains all the switches, power/on lights, and circuit breakers for the protection of all motors, the panel being mounted in a hinged 1 h 1 blister cabinet 65, to be closed at night for protection against vandalism and against freezing of liquids - in flow controls.

The control side of the machine, flowmeter to monitor and solution, and three water, air, and solution panel is mounted on the right and provides motor controls, a the mixing water flow, and air on/off ball valves which control respectively.

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Claims

CLAIMS:

1. Apparatus for producing aerated cementitious material, including a first hopper for cement, means for conveying cement from the first hopper to a mixing means, a second hopper for a filler material and means for conveying filler material from the second hopper to the mixing means, said conveying means including a first screw conveyor in the first hopper and a plurality of screw conveyors in the second hopper, each of said screw conveyors having its respective constant speed drive means, and said second hopper having a sidewall which is inclined inwardly to overhang the adjacent s2rew c2n,e,.,-,.

2.

Apparatus as claimed in claim 1, in

3. Apparatus for producing aerated cementitious material, substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.

Published 1988 at The Patent Office. State House. C671 High Holborri. London WC1R 4TP. Further copies may be obtained from The Patent Office, S2lec Branch St Ma!.; Oray Orp.r-g.2n Ken', BRE 3RE Printed by M. IC. St. Mary C-ay. Ken. 1 87.

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