GB2376655A

GB2376655A - A dispenser for a flowable and settable material

Info

Publication number: GB2376655A
Application number: GB0201386A
Authority: GB
Inventors: Roger Curtois Brandon Taylor
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-01-26
Filing date: 2002-01-23
Publication date: 2002-12-24
Anticipated expiration: 2022-01-23
Also published as: GB0201386D0; GB0102031D0; GB2376655B

Abstract

A dispenser, particularly for lightweight concretes, and comprises a plurality of ducts (10) each with a dispensing nozzle (15) and a poker vibrator (16) disposed within the dispensing nozzle (15) to cause agitation of the concrete passing through the nozzle. The vibration causes pre-compaction of the concrete and controls the flow through the nozzle. Flow of the concrete is discontinued with the poker vibrator in a non-operative condition. The dispenser may be mounted at the base of a supply hopper 22 mounted on a carriage 23 for travel along rails 24 for passage across a mould table 26 upon which are located plural moulds 25. A float levelling plate (20) (Figure 5 - not shown) may be adjustably fixed to the trailing size of the nozzle section 15. An external vibrator may cause the nozzle section itself to vibrate.

Description

A DISPENSER FOR A FLOWABLE AND SETTABLE MATERIAL THIS INVENTION concerns a dispenser for a flowable and settable material such as thixotropic lightweight concrete.

Lightweight concrete mixes are advantageous in certain applications. However, the properties of such materials make it important for them to be placed rapidly and very accurately into moulds.

In the production of, for example, fencing posts, where a number of elongate moulds are placed side-by-side, conventional dispensers do not feed the concrete rapidly into narrow moulds without overdosing which results in spilling of the concrete around the moulds and the need subsequently to spoon concrete from places where there is an overdose to places where there is an underdose. This operation, apart from being wasteful in time and personnel is particularly difficult with lightweight concretes, since such materials do not respond well to physical manipulation. This results in badly formed products.

An object of the present invention is to provide a dispenser, particularly though not exclusively, for lightweight concretes, which is designed to suit a narrow mould aperture and to assist the flow using a

device which partially pre-compacts the concrete during its passage through the dispenser.

According to the present invention there is provided a dispenser for flowable and settable materials, comprising a duct with a dispensing nozzle at its lowermost end, means disposed with respect to the dispensing nozzle to cause agitation of the material passing there through, and means selectively operable to enable and disable material flow from the duct through the nozzle.

Preferably, the agitation means comprises a poker vibrator, and the relative dispositions of the poker vibrator and the dispensing nozzle are determined such that flow of material is discontinued with the poker vibrator in a non-operative condition.

The poker vibrator may be adjustable in height relative to the dispensing nozzle.

The nozzle may have side skirts to prevent splashing.

The nozzle may have a float leveller disposed so as to float upon and to level, the material dispensed from the hopper.

The side skirts and float leveller may be adjustable relative to the hopper.

Several such ducts/nozzles may be mounted side-by-side thus to dispense material simultaneously into several moulds.

The ducts may be mounted on a carriage thus to traverse across the moulds.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which :- Fig. 1 is an end elevation of a multiple dispenser made in accordance with the invention; Fig. 2 is a side elevation thereof ; Fig. 3 is a plan thereof; Fig. 4 illustrates a practical application of the dispenser; and Fig. 5 illustrates, in perspective, a single duct and nozzle forming a part of the dispenser with ancillary parts.

Referring now to the drawing, a dispenser made in accordance with the invention may comprise several tapered ducts 10 mounted side-by-side on a manifold frame 11. Each duct comprises a first converging section 12 at its upper end, feeding a section 13 of uniform rectangular cross-section. This in turn feeds a second converging section 14 leading to a nozzle section 15 of uniform rectangular cross-section at its lowermost end which is open to feed the contents into a mould.

Each duct 10 includes a poker vibrator 16 suspended therewithin so that its lowermost end region 17 is disposed within the nozzle section 15, and extends downwardly therein almost to its open lower end.

As can be seen from Figs. 1 to 3, each nozzle section 15 is elongate in shape being equal in width to the section 13 in one dimension but narrowed by the converging section 14 in the other.

The diameter of the poker vibrator 16, particularly in its lowermost region 17, occupies approximately three quarters of the width of the nozzle section in its narrower dimension and approximately one half of its width in the wider dimension. In this way, by a careful selection of the overall dimensions of the nozzle sections when related to the thixotropic nature of the material to be dispensed, the poker vibrator within each nozzle section can enable and disable flow of the material

when it is operative and in-operative respectively. Thus, discontinued vibration serves to stop the flow of material and so the poker vibrator serves effectively as a flow control valve.

Referring now to Fig. 4 the dispenser may be mounted at the base of a supply hopper 22 mounted on a carriage 23 for travel along rails 24. Thus the assembly may pass across a mould table 26 upon which are located a plurality of moulds 25 for example for concrete fencing posts, such that all moulds may be filled simultaneously by the traversing motion of the carriage 23.

Referring now to Fig. 5 it will be seen that a pair of side members or skirts 19 may be adjustably affixed to the longer sides of each nozzle section 15, and a float levelling plate 20 may be adjustably fixed to the trailing side of the nozzle section, the arrow 21 depicting the direction of travel of the assembly. Thus, the float leveller 20 rides upon the surface of the dispensed concrete thus to have a levelling and smoothing action.

The poker vibrators 16 serve not only to control the flow of concrete through each nozzle section but also partially to pre-compact the concrete as it flows into the mould thus requiring little or no further compaction within the mould. This is of particular advantage with the use of certain lightweight concretes which respond poorly to physical

manipulation. The pre-compaction also helps to prevent segregation of those components of the mix which vary in density.

Poker and nozzle sizes can be determined to suit particular mould widths. A typical application is to produce fence posts having a length up to 5metres with a cross-section of, for example, 92mm by 120mm. In this example the nozzles will be 75mm by 100mm in crosssection and the poker diameter will be 45mm.

By placing the nozzles, with or without side skirts 19, closely above each mould top, accurate and rapid dosing of the concrete into the moulds is achieved with no overspill or splashing. This is of particular advantage when using lightweight concrete mixes. The side skirts may be equipped with a lateral flange 22 to determine the height of the nozzle relative to that of a mould top.

The float leveller 20 is set just above the lowest level of the skirts 19 thus to produce an overlay or ridge of concrete at a level just above the top of the mould. Subsequent vibration of the mould itself causes the concrete to settle to the required level of the top of the mould, thus further compacting the material. In practice, the material is precompacted by the poker vibrator, to about 80% of full compaction, the remaining 20% being achieved, if required, by vibrating the mould after filling.

In an alternative arrangement, lightweight concrete mixes may be dispensed from nozzles having a further reduced cross-section, with an external vibrator causing the nozzle section itself to vibrate thus to assist the flow and partially to pre-compact the material. In this case however, an additional valving arrangement might be needed to stop the flow when required.

A benefit of providing the agitation means in the form of an internal poker vibrator disposed within the material in the nozzle is a substantial reduction in noise level when the dispenser is operating.

It may be advantageous to enable vertical adjustment of the poker vibrators in relation to the dispensing nozzles in order to provide a control over the rate of flow of concrete through the nozzle. This can be particularly useful when compensating for changes in the viscosity or thixotropicity of the concrete mix. The height adjustment means of the poker vibrators may be automated with a feedback system which detects the rate of flow of concrete and makes adjustments in height of the individual poker vibrators to provide a constant flow rate. Alternatively, the flow rate may be modified during dispensing of the concrete so that, for example, an initial period of rapid flow is followed by a gradual reduction as the mould fills.

If required, the nozzle outlet formation may be modified by extending it at an inclined angle which would prevent concrete dripping from the nozzle and also may be more effective in directing the concrete into smaller apertures, for example, by narrowing the outlet cross-section.

Claims

1. A dispenser for flowable and settable materials, comprising a duct with a dispensing nozzle at its lowermost end, means disposed with respect to the dispensing nozzle to cause agitation of the material passing there through, and means selectively operable to enable and disable material flow from the duct through the nozzle.

2. A dispenser according to Claim 1, wherein the agitation means is a poker vibrator disposed within the dispensing nozzle and the relative dispositions of the poker vibrator and the nozzle are determined such that flow of the material is discontinued with the poker vibrator in a non-operative condition.

3. A dispenser according to Claim 1 or Claim 2, wherein the nozzle has at least one side skirt to prevent splashing of the material.

4. A dispenser according to any preceding claim, wherein the nozzle includes a float leveller disposed so as to float upon and to level, the material dispensed from the hopper.

5. A dispenser according to Claim 3 and 4, wherein said at least one side skirt and said float leveller are adjustable relative to the hopper.

6. A dispenser according to any preceding claim, including several of such ducts and nozzle assemblies mounted side-by-side thus to dispense material simultaneously into several moulds.

7. A dispenser according to any preceding claim, wherein said duct or ducts are mounted on a carriage thus to traverse across the mould or moulds.

8. A dispenser according to Claim 2, wherein the poker vibrator is adjustable vertically with respect to its associated nozzle whereby to control the flow of material there through.

9. A dispenser according to any preceding claim, wherein the dispensing nozzle is disposed at an inclined angle thus to direct the material in a direction other than vertically.