GB2421946A

GB2421946A - Treating water with copper and zinc wire

Info

Publication number: GB2421946A
Application number: GB0526139A
Authority: GB
Inventors: David William Armfield
Original assignee: ARMFIELD HOLDINGS Ltd; SALAMANDER
Current assignee: Salamander Engineering Ltd
Priority date: 2005-01-11
Filing date: 2005-12-22
Publication date: 2006-07-12
Anticipated expiration: 2025-12-22
Also published as: GB2421946B; GB0526139D0; GB0500450D0

Abstract

A method of treating liquid (e.g. water) comprises passing the liquid through a mesh comprising copper wire and zinc wire. The method is particularly suitable for the treatment of hard water and the mesh may be used e.g. in an iron, kettle or a domestic water tank. Preferably the copper and zinc wires are intermingled to form a uniform structure.

Description

The invention relates to treatment of liquid, particularly water, held in

storage e.g. in a kettle or a cold water supply such as a tank in domestic, commercial or large-scale installations.

The presence of hard water is often regarded as a disadvantage as it tends to form scale on pipes, containers and heating appliances. The hard water may be temporary hard water containing calcium bicarbonate or permanent hard water containing calcium and/or magnesium salts. Changes in temperature cause deposits of insoluble calcium and/or magnesium salts to form, which can deposit on the insides of kettles and pipes etc. One object of this invention is to provide a descaling water treatment system which is highly effective against hard water, gives a consistent water treatment over a period, can be easily replaced, has a wide range of applications and is cost-effective.

According to one aspect of the present invention a method of treating liquid comprises passing the liquid through a mesh comprising copper wire and zinc wire.

According to another aspect of the present invention there is provided a method of reducing scale build up in a liquid system by passing liquid through a mesh comprising copper wire combined with zinc wire.

According to another aspect of the present invention there is provided a method of making a liquid treatment system comprising combining together at least one copper wire and at least one zinc wire to form a mesh.

According to another aspect of the present invention a liquid treatment system comprises a mesh comprising copper wire and zinc wire.

When treating water to reduce scale build-up it is believed that the use of zinc and copper are effective because of their relative positions in the electrochemical series.

The invention is particularly applicable to the treatment of static or circulatory water or dilute aqueous solutions, but could also be used to treat other systems such as water / oil mixtures e.g. suds-oil' as used in manufacturing and machine-shop applications.

Examples of applications include use in a water conduit to protect boilers, whole house water systems, water tanks, cylinders or appliances such as washing machines and dishwashers. The mesh can be used loose or in an open container (e.g. a cage) allowing liquid flow through it for use in kettles, cold water tanks or steam generators e.g. modern steam irons.

Steam generators generally come in two versions: One version has a separate cold water top-up tank in which at least one mesh could be positioned. A second (smaller) version has a funnel to allow the unit to be filled, and in this type a mesh could be positioned in the funnel.

A function of the container means e.g. a cage, conduit or cartridge, where used, is to facilitate correct positioning of the mesh and ease of replacement.

By a mesh' is meant a network defining spaces through which water can pass. The mesh may be formed by knitting, stitching, braiding, weaving or matting the copper and zinc wires together. Preferably the mesh is formed so that it is self-supporting, coherent, will remain in one piece and will not fall apart when in use. Preferably there is a majority by surface area of copper compared to zinc e.g. more than 1:1 and up to 6:1 copper to zinc, more preferably in a ratio between 2:1 and 4:1 and advantageously around 3:1 copper to zinc. There may be one continuous wire of each metal or a plurality of one or both. The wires may be straight or crimped prior to being combined together, or may be crimped and/or compressed after combination.

In a preferred embodiment the copper and zinc wires are substantially completely intermingled so that the mesh is substantially uniform throughout, and in another embodiment the copper and zinc wires are layered e.g. in a sandwich arrangement comprising a zinc layer between two layers of copper.

Preferably the wires in the mesh will be bent rather than straight e.g. a continuous copper wire intermingled with a continuous zinc wire. However, it may be possible to use straight lengths of copper and zinc wire bundled together but held in a spaced apart configuration to allow liquid to pass through the construction. The diameter of the wires may be e.g. from 0.25mm to 1mm.

Preferably the copper wire consists substantially completely of copper. Alternatively, the copper wire may consist of copper surrounding another metal or alloy e.g. by plating or coating, but in that case the copper must substantially constitute the exterior or the copper wire i.e. it will be copper in contact with water passing through the mesh.

Preferably the zinc wire consists substantially completely of zinc. Alternatively, the zinc wire may consist of zinc surrounding another metal or alloy e.g. by plating or coating, but in that case the zinc must substantially constitute the exterior of the zinc wire i.e. it will be zinc in contact with water passing through the mesh.

Examples of applications of the mesh are in a kettle, water filter, ball valve, tank or pipe. The mesh of the present invention can be made in various product formats which could vary considerably depending on the end use application. The system can be adapted for use with domestic shower-units and can even be fitted within the showerhead.

The mesh, which is preferably flexible, may be combined with a filter and/or a support means, when installed where required in the flow of liquid. For example, when used in a kettle it would preferably be supported above the normal water level so that it is not permanently in water, but in a position where water filling the kettle would pass through it e.g. it could be in the spout. Alternatively, it could be supported beneath the lid when the kettle is of the type that is filled through the lid. When used in a pipe or boiler or tank, the mesh would usually be permanently submerged in the liquid.

When tested under laboratory conditions the mesh according to the present invention was found to give great improvements in reduction of scale production in synthetically prepared hard water. This was measured accurately by weighing the scale deposited from tap water to which had been added calcium chloride and sodium bicarbonate. The apparatus consisted of a plastic tank, a heating element and means for magnetically stirring the water during the test. Test results varied according to the flow of water. Measured against a control (i.e. no copper/zinc mesh present), there was a scale-forming rate reduction of 78% on the heater and 95% in the water. In the tests, the copper and zinc levels increased slightly but were well below the maximum levels for drinking water as laid down by the World Health Organisation for taste and appearance.

It will be appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable combination.

Claims

CLAIMS: 1. A method of treating a liquid comprises passing the liquid

through a mesh comprising copper wire and zinc wire.
2. A method according to claim 1 wherein the liquid is water.
3. A method according to claim 1 or 2 wherein the mesh is self-supporting.
4. A method according to any preceding claim wherein the mesh is held in a container through which the liquid passes.
5. A method according to any preceding claim wherein there is a majority by surface area of copper compared to zinc.
6. A method according to claim 5 wherein the ratio of copper to zinc by surface area is from more than 1:1 to 6:1.
7. A method according to claim 6 wherein the ratio of copper to zinc by surface area is from 2:1 to 4:1.
8. A method according to claim 7 wherein the ratio of copper to zinc by surface area is 3:1.
9. A method according to any preceding claim wherein the mesh comprises one continuous copper wire and one continuous zinc wire.
10. A method according to any preceding claim wherein the copper wire and zinc wire are substantially completely intermingled.
11. A method according to any preceding claim wherein the copper wire and zinc wire are bent.
12. A method according to any preceding claim wherein the copper wire and zinc wire have a diameter in the range 0.25mm and 1mm.
13. A method according to any preceding claim wherein the copper wire consists substantially of copper.
14. A method according to any preceding claim wherein the zinc wire consists substantially of zinc.
15. A method according to any preceding claim when used to reduce scale build up.
16. A method according to claim I and substantially as herein described.
17. A liquid treatment system comprises a mesh of copper wire and zinc wire.
18. A liquid treatment system according to claim 17 and having the feature of any one of claims 3 to 14.