GB2159722A

GB2159722A - Mixing machines

Info

Publication number: GB2159722A
Application number: GB08414640A
Authority: GB
Inventors: Ronald Nigel Adams
Original assignee: AERCRETE
Current assignee: AERCRETE
Priority date: 1984-06-08
Filing date: 1984-06-08
Publication date: 1985-12-11
Also published as: GB8414640D0

Abstract

The machine comprises a chassis 10 on which are mounted a power unit 14, storage hoppers 15, 16 for at least two materials to be mixed, a mixing and conveying chamber 21 containing a mixing and conveying screw for mixing the materials and delivering the mixture to an outlet, and feed augers 17, 18, 19 associated with the storage hoppers. The mixing and conveying chamber 21 is disposed with its length extending longitudinally of the chassis 10 and at one side of the machine, and the feed augers 17, 18, 19 extend transversely of the chassis 10 from below the respective hoppers 15, 16 directly to the inlet end of the mixing and conveying chamber 21. Such an arrangement is particularly convenient and long-wearing in use. <IMAGE>

Description

SPECIFICATION Mixing machines This invention relates to mixing machines for materials such as cement, sand and a foaming agent, to produce lightweight concrete. However the apparatus can also be adapted for use in making concrete, using cement, sand and aggregate.

There are in existence machines particularly for producing lightweight concrete and many of these produce successive batches of mixed materials. Another type of machine has the ability to produce the mixed materials on a continuous basis and this is more convenient in many circumstances. Such a machine has hoppers or other storage means for the ingredient materials and these are fed into a chamber containing a mixing and conveying screw which mixes the materials together and delivers them to an outlet of the machine.

Such an existing machine however.has certain shortcomings both in convenience of use and in its construction.

It is therefore the object of the invention to provide a mixing machine which is particularly convenient in use and which is versatile in its ability to produce mixtures for varying requirements.

According to the present invention there is provided a mixing machine comprising a chassis on which are mounted a power unit, storage hoppers for at least two materials to be mixed, a mixing and conveying chamber containing a mixing and conveying screw for mixing the materials and delivering the mixture to an outlet, and feed augers associated with the storage hoppers respectively, the mixing and conveying chamber being disposed with its length extending longitudinally of the chassis and at one side of the machine and the feed augers extending transversely of the chassis from below the respective hoppers directly to the inlet end of the mixing and conveying chamber.

Preferably the machine also includes a foam generator arranged to deliver foaming agent into the mixing and conveying chamber.

Conveniently the hoppers are so shaped that their lower outlets are grouped adjacent each other, the feed augers being positioned below the respective lower outlets and also adjacent each other and substantially parallel with one another.

Screw type augers are preferably used.

Advantageously the power unit is mounted at or near one end of the chassis and the storage hoppers are disposed at or near the other end.

The invention will now be described by way of example and with reference to the accompanying drawing, the single figure of which is a diagrammatic side elevation view of a mixing machine constructed in accordance with the invention.

The machine shown has a chassis, indicated generally at 10, mounted on two pairs of wheels 11 situated near the centre of the chassis and on respective suspensions, indicated generally at 1 2. At one end there is a support leg 1 3 or pair of such legs The chassis carries at one end a housing 14 for a power unit which may conveniently be a diesel engine. Near the other end of the chassis there are storage hoppers, two of which 1 5 1 6 are shown. These are generally of funnel shape having wider tops each having a lid and narrower lower ends which comprise respective outlets. The hoppers can be filled with respective ingredients to be mixed such as cement, sand and aggregate.

In the lower outlet end of each hopper there is an entry to a generally cylindrical channel, each such channel containing an auger of screw type. The augers 17, 18, 19, of which three are fitted in the machine shown, extend in parallel with one another and are inclined at a shallow angle downwardly towards one side of the machine. These serve as respective feed augers for the materials contained in the respective hoppers and each is driven by a separate motor through a control which enables the speeds of the respective augers to be varied as required.

At one side of the machine being that towards which the lower ends of the augers 1 7, 18, 19 are directed, is a mixing and conveying chamber 21. This chamber is in the form of an elongated trough with a semicylindrical base. The upper end may be open or partially closed by a grid. The length of the mixing and conveying chamber 21 extends longitudinally of the machine chassis and the base is upwardly inclined at a shallow angle, as shown in the drawing. Contained within the mixing and conveying chamber is a screw conveyor or auger which is preferably of the kind described and claimed in Patent Application Number 8314083. It comprises a central shaft 22 mounted in bearings 23, 24, at the two opposite ends. One end, in this case the lower, is attached to a drive motor 25 whereby the screw can be rotated.Fixed to the shaft are helical blades 26 most of which are hollow but some of which are solid. Intermediate some of the blades, but not shown in the drawing, are paddles which provide for counter-rotation to aid mixing. In this example, also, the lower end of the screw may be detachable through the joint for this is not illustrated. The lower one quarter, or approximately one quarter of the length of the screw, is thus detachable. It has been found that this portion of the conveyor receives the maximum abrasion from the material and therefore wears out sooner than the remaining parts of the screw. It is therefore possible to remove and replace this without the need for replacing the rest of the screw.

The three augers 1 7, 18, 19, are posi tioned approximately over the lower end of the screw in the mixing and conveying chamber 21 and deliver quantities of the respective ingredients into the lower end. A water supply pipe (not shown) is provided to deliver water at a convenient position in the chamber 21.

This may be positioned between the augers 1 7 and 1 8. There is also a foam generator (not shown) which delivers a foaming agent through a pipe 27, into the mixing and conveying chamber when required. At the upper end of the chamber 21 there is an outlet chute 28 leading into a funnel 29 which in turn connects with a pipe 30. This leads to a pump indicated at 31 which delivers the material to an outlet on the external face of the machine. A flexible hose can be connected to such outlet for delivery of the material to a position remote from the machine.

With this apparatus it is possible to provide a continuous supply of concrete. The proportions of the ingredients can be varied by adjusting the speeds of the augers 17, 18, 19, so as to vary the proportions of the ingredients entering the mixing and conveying chamber Preferably, the sand enters the chamber before the cement since it is found that this is advantageous in reducing abrasion. Furthermore, the sand is wetted as it enters the mixing chamber.

The foam generator may be of variable type so as to vary the expension of the concrete and therefore its strength and specific weight.

Control of the means for varying the ingredients may be computerised.

Although the machine is intended primarily for the production of lightweight concrete comprising a mixture of cement and sand and a foaming agent, it is possible to use it as a concrete mixer for mixing together quantities of sand, cement and aggregate. Furthermore, the apparatus may be on a large scale producing high volumes of materials or, alternatively, it may be built on a small scale.

The positioning of the power unit 14 at one end and the hopper for storing the material at the other end, gives good weight distribution for the chassis. Also, the positioning of the augers 17, 18, 1 9 transversely of the length of the mixing and conveying chamber 21 enables the augers to deliver directly into the mixing and conveying chamber, thus minimis ing wear on parts since the delivery path from the storage hopper to the mixing and convey ing chamber is minimised.

Modular construction of the apparatus enables a number of different combinations to be used according to requirement.

Claims

1. A mixing machine comprising a chassis on which are mounted a power unit, storage hoppers for at least two materials to be mixed, a mixing and conveying chamber containing a mixing and conveying screw for mixing the materials and delivering the mixture to an outlet, and feed augers associated with the storage hoppers respectively, the mixing and conveying chamber being disposed with its length extending longitudinally of the chassis and at one side of the machine and the feed augers extending transversely of the chassis from below the respective hoppers directly to the inlet end of the mixing and conveying chamber.

2. A machine according to claim 1, which also includes a foam generator arranged to deliver foaming agent into the mixing and conveying chamber.

3. A machine according to claim 1 or 2, wherein the hoppers are so shaped that their lower outlets are grouped adjacent each other, the feed augers being positioned in the respective lower outlets and also adjacent each other and substantially parallel to one another.

4. A machine according to any preceding claim, wherein the feed augers are screw type augers.

5. A machine according to any preceding claim, wherein the power unit is mounted at or near one end of the chassis and the storage hoppers are disposed at or near the other end.

6. A machine according to any preceding claim, which also includes a supply conduit for delivering fluid to the mixing and conveying chamber.

7. A mixing machine substantially as hereinbefore described with reference to the acompanying drawing.