WO1995001829A1

WO1995001829A1 - Apparatus and method for dissolving solids

Info

Publication number: WO1995001829A1
Application number: PCT/IB1994/000210
Authority: WO
Inventors: Desmond Graham Prosser; René ASSENBERG
Original assignee: Drew Ameroid Nederland B.V.
Priority date: 1993-07-05
Filing date: 1994-06-27
Publication date: 1995-01-19
Also published as: GB9313862D0; AU7081894A

Abstract

Apparatus for dissolving solid chemical materials in water comprises a container (1) having a top closure member (3), an upper cylinder (2) for loading with solid chemical material to be dissolved, and a dissolving chamber (8) below the cylinder (2). The dissolving chamber (8) includes a containing wall (16) provided with a plurality of orifices (19) through which water passes to the chamber interior. The orifices are so arranged that upon the supply of water therethrough a generally swirling flow of water is provided in the chamber. A support and outlet filter screen (22) is disposed within the container (1) at the base of the dissolving chamber (8) through which water solution may pass, but through which solid material is not able to pass, to an outlet below the filter screen.

Description

APPARATUS AMD METHOD FOR DISSOLVING SOLIDS

This invention relates to apparatus and methods for dissolving solids.

There are many circumstances where it is necessary to provide chemical additives to a water supply, be it the addition of salt to water to provide a saline solution, or the introduction of biocides for water or effluent treatment processes or any solid/solution processes.

Such chemicals can be transported from their place of manufacture to that of intended use in liquid form, such as a concentrated solution in water of the chemical concerned.

However transport of such chemicals in solution is undesirable, both from the point of view of transporting a considerable volume of water with the chemical (which reduces the economics of the transporting operation), and that the transport of liquids which can be corrosive or toxic when in the form of a concentrated solution, is, because of the risk of accident during transport, undesirable.

It has been proposed therefore that such chemicals should be transported in a solid condition and then subjected to processing to dissolve them in water for use at or adjacent to the required usage point.

However the transport of the chemical in solid form does then require apparatus for carrying out the process of dissolving the chemicals in water prior to use, and proposals have been made for such apparatus, typically in which, in a pressurised vessel, water is fed upwardly through the vessel filled with the solid chemical concerned, often either in powder or in tablet form dissolving the chemical during passage, to an outlet via filters for preventing any ongoing transmission of solids. Such devices have not been found to be fully satisfactory, in that to achieve satisfactory throughput, pressure vessels are often used, which usually have restricted openings for refilling the vessel with the chemical solid for dissolving, and the filters within the vessel have been found to be prone to fouling and subsequent blocking by small particles of the product. For this reason, the dissolving capability of the apparatus is severely restricted since the water flow is limited by the tendency of the chemical solids to lodge around the outlet filter. In addition such prior apparatus, with its restricted sized opening for filling, produces handling problems with materials which can be toxic to a greater or lesser extent.

The blocking effect by fine material, it is to be noted, applies not only when powder material is used but equally when material in tablet form for example is used, since the dissolving action necessarily involves an eroding effect of the tablets to produce a quantity of fine material which can block the outlet filter of the apparatus.

It is an object of the present invention to overcome or at least significantly reduce the above mentioned problems and provide apparatus and a method for dissolving solid chemical materials in water of a simple and effective nature.

In accordance with one aspect of the invention there is provided apparatus for dissolving solid chemical materials in water comprising a container having a top closure member; an upper portion for loading with the solid chemical material to be dissolved; a dissolving chamber below and continuing from the upper portion, the dissolving chamber including a containing wall therearσund which is provided with a plurality of orifices therethrough; a supply of water to the orifices from outside the chamber, the orifices being so arranged that upon supply of water therethrough a generally swirling flow of water is provided in the chamber; and a support and outlet filter screen disposed within the container at the base of the dissolving chamber through which water solution may pass, but through which solid material is not able to pass, to a water solution container outlet below the filter screen.

The water supply to the dissolving chamber via the orifices may be by means of a hollow supply compartment disposed around the dissolving chamber, connecting to the orifices and provided with a water inlet.

Each of the orifices may be inclined at an angle to the part of the wall of the chamber through which it passes.

The orifices may all be inclined at an equal angle to the parts of the wall of the chamber through which they pass, and may be aligned in one or more horizontal planes to provide a circulatory motion to the water in the dissolving chamber.

Alternatively a more complex pattern of inclination of orifices may be provided so as to create a more turbulent water motion within the chamber.

The container may have a solution collection compartment below the filter screen connecting to an outlet from the container.

In accordance with another aspect of the invention there is provided a method of dissolving solid chemical materials in water comprising loading the solid chemical material into an upper portion of a container having a top closure member; allowing the material to pass to a dissolving chamber below and continuing from the upper portion; supplying water to the dissolving chamber via a plurality of orifices through a containing wall around the dissolving chamber so arranged that a generally swirling flow of water is provided in the chamber; and passing water solution only through a support and outlet filter screen disposed at the base of the dissolving chamber to a container outlet.

In operation the top closure member is removed, solid chemical to be dissolved is placed in the container through its upper portion so as substantially to fill the same from the mesh screen through the dissolving chamber and into the upper portion to the extent required. The closure member is replaced and water is then fed to and passes through the multiplicity of inclined orifices into the dissolving chamber where it meets the solid material contained therein and provides a swirling force of water upon the solid material within the dissolving container which has the effect of creating abrasion between particles of the solid chemical, and between particles of the solid chemical and the filter screen at the base of the dissolving chamber whereby a rapid dissolving action on the solid material is applied, whilst at the same time the filter screen is prevented from becoming blocked by particles of solid material by the continual movement of the water on the top surface thereof, as well as the passage of water solution therethrough to the outlet disposed therebelow.

In a further aspect, there is provided apparatus for dissolving solid chemical materials in water comprising a container having a top closure member; an upper portion for loading with the solid chemical material to be dissolved; a dissolving chamber below and continuing from the upper portion, the dissolving chamber including a containing wall therearound which is provided with at least two vertically spaced generally horizontal arrays of inclined orifices therethrough; means for supplying water to a supply compartment disposed around the dissolving chamber and in communication with the orifices which are arranged such that the flow of water therethrough produces a generally swirling flow in the chamber; and a support and outlet filter screen disposed within the container at the base of the dissolving chamber through which water may pass, but through which solid material is not able to pass, to a container outlet below the filter screen.

In order that the invention may be more readily understood one embodiment thereof may now be described by way of example with reference to the accompanying drawings in which:-

Figure 1 is a cross section of one embodiment of dissolving apparatus according to the invention; and

Figure 2 is a sectional plan view of a portion of the dissolving chamber of the apparatus of Figure 1.

Referring now to the drawings it is to be noted that the apparatus is predominantly formed of an appropriate plastics material such as polypropylene or polyvinyl chloride. The apparatus comprises a container 1 which includes an upper cylinder 2 having a top cover 3 connectable to a welded on outer annular flange 6 by means of bolts 4 (one only shown) and having a gasket 5 therearound for sealing purposes. The upper cylinder 2 of the container is welded to a lower annular flange 7 and continues into a dissolving chamber 8.

This chamber is of reduced internal diameter compared to that of the upper cylinder 2 and is formed from an outer lower cylinder 9 of slightly greater diameter than the upper cylinder 2 welded at its top to an annular outer flange 10 which is sealingly connected by means of an annular gasket 11 and nuts 12 and bolts 13 (one of each only shown) to a radially outer part of flange 7. Flange 7 has a radially inner funnel shaped part 29 for assisting flow of material therepast to the dissolving chamber 8.

Welded to the cylinder 9 at the upper end thereof are two radially inwardly extending flanges 14, 15, a sleeve 16 being welded between their radially inner ends, thereby defining a water supplying annular compartment 17 about the dissolving chamber.

A water inlet connecter 18 is mounted in the side of the lower cylinder 9 connecting to the annular compartment 17.

It is to be observed from the Figures that the sleeve 16 is provided with a plurality of bored orifices 19,20 therethrough, in two vertically separated rows, each orifice being inclined at a tangent to the inner diameter of the sleeve 16.

At the base of the dissolving chamber is a composite support and filter 22 which comprises a fine mesh filter screen of suitable plastics material (such as polypropylene or polyvinyl chloride) carried by a stainless steel mesh support screen disposed thereunder. The composite support and filter 22 supports the volume of chemical material thereabove and acts as a filter preventing egress of solid material from the dissolving chamber 8 to a solution collecting compartment 24 at the lowermost part of cylinder 9.

It is to be observed that the mesh screen 22 is supported against flange 15 by means of another flange 23 therebelow seated on a shoulder 21 of cylinder 9, and additionally is provided with sealing gaskets 25, 26.

The solution collecting compartment 24 is provided with a water solution outlet connector 27 in the wall of the cylinder.

The bottom end of cylinder 9 of the container is welded to a base 27 for securement and sealing, and may be provided with bores 28 to enable the base to be secured on an appropriate platform.

The total assembly may, for purposes of strength and impact resistance for example, be provided with enwrapment by glass reinforced plastic (not shown).

In operation the container down to and including the dissolving chamber 8 (ie down to the mesh screen 22) may be filled with the chemical to be dissolved, which may be in a granular form for example. Water is then applied to the inlet 18 to fill the annular compartment 17 and pass through the inclined bores 19, 20 in the internal sleeve 16 to form a rotary or swirling flow of water within the dissolving chamber 8 which in turn will have a similar swirling rotational effect upon the granules of solid material within the chamber. This swirling action will cause abrasion between the granules, and between the granules and the mesh screen 22 and will rapidly dissolve the granules which will pass in solution through the mesh screen. This will be kept clear from blockage by fine particles by the swirling action of the water. As dissolved particles pass through the mesh screen, the mass of solid material in the upper portion of the container will move down to take its place until all solid material has been used.

The arrangement of the invention has a number of considerable advantages including the following:-

(a) Because the opening for the solids is for the full width of the cylinder 2 (which is not used under significant pressure) easy filling is possible. In practice the pressure within the container can be limited to three bar.

(b) The mechanics of the operation of the apparatus are such that there is improved water to chemical solid contact by what can be regarded as a partial "fluidising" of the solid chemical bed within the dissolving section.

(c) The swirling water action within the dissolving chamber, having in essence the effect of "fluidising" the material within the dissolving chamber, leads to scouring of the screen mesh and prevention of the build up of particulate material on the screen which in turn protects the screen from blockage. The effect of this is that the apparatus will maintain its desired flow characteristics.

(d) By varying the inlet flow, and by varying the size of the inner sleeve 16, in relation to its internal diameter and/or in relation to its height, and the number and size of the orifices, variable output from the apparatus is obtainable.

(e) With toxic chemicals, where the customer is not willing to, or should not, handle the toxic solid chemical, the plain filling cap can be replaced by a valve sealing unit, for example, capable of coupling to a bulk container, so that the apparatus may then form part of a returnable container system where the user need have no contact in any way with the solid chemical material.

It is to be understood that the foregoing is merely exemplary of apparatus and methods for dissolving solids and that modifications can readily be made thereto without departing from the true scope of the invention as set out in the appended Claims.

Claims

1. Apparatus for dissolving solid chemical materials in water comprising a container having a top closure member; an upper portion for loading with the solid chemical material to be dissolved; a dissolving chamber below and continuing from the upper portion, the dissolving chamber including a containing wall therearound which is provided with a plurality of orifices therethrough; a supply of water to the orifices from outside the chamber , the orifices being so arranged that upon supply of water therethrough a generally swirling flow of water is provided in the chamber; and a support and outlet filter screen disposed within the container at the base of the dissolving chamber through which water solution may pass, but through which solid material is not able to pass, to a water solution container outlet below the filter screen.

2. Apparatus as claimed in Claim 1 wherein the water supply to the dissolving chamber via the orifices by means of a hollow supply compartment disposed around the dissolving chamber, connecting to the orifices and provided with a water inlet.

3. Apparatus as claimed in Claims 1 or 2 wherein each of the orifices is inclined at an angle to the part of the wall of the chamber through which it passes.

4. Apparatus as claimed in Claim 3 wherein the orifices are all inclined at an equal angle to the parts of the wall of the chamber through which they pass.

5. Apparatus as claimed in any one of the preceding Claims wherein the orifices are aligned in one or more horizontal planes in the wall of the chamber through which they pass.

6. Apparatus as claimed in any one of the preceding Claims including a solution collection compartment disposed below the filter screen connecting to an outlet from the container.

7. A method of dissolving solid chemical materials in water comprising loading the solid chemical material into an upper portion of a container having a top closure member; allowing the material to pass to a dissolving chamber below and continuing from the upper portion; supplying water to the dissolving chamber via a plurality of orifices through a containing wall around the dissolving chamber so arranged that a generally swirling flow of water is provided in the chamber; and passing water solution only through a support and outlet filter screen disposed at the base of the dissolving chamber to a container outlet.

8. Apparatus for dissolving solid chemical materials in water comprising a container having a top closure member; an upper portion for loading with the solid chemical material to be dissolved; a dissolving chamber below and continuing from the upper portion, the dissolving chamber including a containing wall therearound which is provided with at least two vertically spaced generally horizontal arrays of inclined orifices therethrough; means for supplying water to a supply compartment disposed around the dissolving chamber and in communication with the orifices which are arranged such that the flow of water therethrough produces a generally swirling flow in the chamber; and a support and outlet filter screen disposed within the container at the base of the dissolving chamber through which water may pass, but through which solid material is not able to pass, to a container outlet below the filter screen.