GB2319788A

GB2319788A - Water saving insert for W.C. cistern

Info

Publication number: GB2319788A
Application number: GB9721848A
Authority: GB
Inventors: Colin John Kerwin
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-10-17
Filing date: 1997-10-16
Publication date: 1998-06-03
Anticipated expiration: 2017-10-16
Also published as: GB2319788B; GB9721848D0

Abstract

A water saving device for water storage vessels such as flush cisterns, the device comprising a perforated plastics bag (11) containing, in granular form, a super-absorbent polymer which, when wetted, expands to two hundred times its pre-absorption volume. The bag is preferably weighted and may be simply placed in a cistern (14) where it rapidly expands to displace between 2 and 5 litres of water within a cistern otherwise containing at least 9 litres, thus significantly to reduce wasteful water consumption.

Description

WATER DISPLACEMENT DEVICE THIS INVENTION concerns a device for displacement of water in water storage vessels such as flush cisterns in sanitary installations and individual W.C. appliances.

Considerable emphasis is currently placed on savings of water in residential and particularly commercial premises and educational premises. A modern W.C. cistern contains in excess of 6 litres of water and many older cisterns presently in use contain 9 or 13 litres of water.

Water authorities have established that the majority of W.C. appliances require only 6 to 7.5 litres of water per flush and so many appliances waste at least 30% of their water content every time the cistern is emptied. Not only does this represent a considerable wastage of water being excessively burdensome upon water supply and waste water treatment installations but is also financially wasteful where water usage is measured by a meter, the consumer paying for water according to the volume of usage.

Simply by reducing the volume of water dispensed from a cistern when flushed, will ensure an appreciable saving in cost and resources, and it is to meet this objective that the present invention provides a water displacement device for water storage vessels such as flush cisterns, the device comprising a flexible container within which is provided a material of a kind which is water-absorbent such as to expand to many times its pre-absorption volume.

Preferably, the container is a bag of a plastics material such as polyethylene, and contains a small and compact quantity of a highly absorbent material which is capable of expanding to 200 or more times its pre-absorption volume when submerged in a water storage tank. Conveniently, the bag also includes a weight so that it shall sink to the bottom of the vessel whereby the bag, after expansion of the absorbent material, resides beneath the flotation member attached to the water inlet valve.

Two embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings, in which:-~ Fig. 1 illustrates a flushing cistern in which there is installed a water displacement device made in accordance with the first embodiment, in a pre-absorption condition; Fig. 2 is a similar view after absorption; Fig. 3 illustrates, in elevation, a flushing cistern containing a water displacement device according to a second embodiment, before absorption; Fig. 4 is a plan view thereof; Fig. 5 is a view similar to Fig. 3 after absorption; and Fig. 6 is a plan view similar to Fig. 4, after absorption.

Referring now to Figs. 1 and 2, a cistern 14 contains a flushing siphon 12 and water to a level as illustrated at 13. There is shown introduced into the cistern 14 a water displacement device 11 comprising a generally rectilinear block of a material which is preferably contained within a perforated polyethylene bag and which, as illustrated in Fig. 2, after a period of submersion within the cistern 14 expands to something like four or five times its original volume.

Referring now to Figs. 3 to 6, in a further embodiment, the bag contains a weight and a small quantity of a superabsorbent material such as a double cross-linked sodium polyacrylate, which is capable of expansion to something like 100 or even 200 times its volume upon absorption of water. Such a material is currently available from Allied Colloids Limited under the brand name SALSORB CL21 or SALSORB CL10. The superabsorbent polymer is available in granular form having an extremely high retention capacity and characteristics such that after expansion its volume is retained.

Rewetting, caused by repeated flushes, does not diminish or deteriorate the material which retains a resilient viscous gel-like consistency. The material is non-toxic and effectively inert in water.

The bag 11 is of perforated polyethylene having upper and lower compartments 15 and 16. The lower compartment is of lesser volume and contains a material such as sand, or, for example, a galvanised steel rod, to act as a weight to hold one edge of the bag down on the base of the cistern 14. The larger upper compartment 15, upon introduction into the cistern, contains a small quantity of the granular superabsorbent polymer, occupying only about 0.5% or less of the volume of the compartment 15.

As can be seen in Fig. 4, the bag, when installed, lies alongside the internal front wall of the cistern, well clear of the flush-siphon assembly 12, the float ball 17 and the usual arm 18 attaching it to a water inlet valve 19.

Referring now to Figs. 5 and 6, the device can be seen after the absorbent material in compartment 15 has expanded to its maximum volume after absorption. Thus, the expanded bag lies across the bottom of the cistern 14, one end of the bag being lodged alongside the siphon assembly 12, the remainder of the bag extending towards an opposite corner of the cistern so that the whole bag lies beneath the float ball 17.

Thus, after absorption of water the device occupies a proportion of the volume of the vessel displacing water and reducing the volumetric content by between 2 and 5 litres. Conveniently, the capacity of a 9-litre cistern may be reduced by this device to 7 litres and a 13-litre cistern to, for example, 8 litres thus, in both cases, complying with the volume of water considered to be sufficient for an adequate flush, this being in the region of 7 litres.

It will be appreciated that a water displacement device of this kind is convenient to install requiring no skill or tools, is effectively everlasting, and non-intrusive and for cisterns with excess capacity enables a considerable saving of water. Expansion occurs usually within 30-60 minutes after submersion in a cistern and once introduced it can simply be forgotten as it requires no further attention or renewal.

The bag containing the absorbent material may be of perforated plastics material or fabric or indeed any other material which may be conveniently packaged for purchase and may remain in the cistern once introduced.

While the water-absorbent material is preferably selected in granular form for convenience of packaging, any material which is capable of expansion to many times its pre-absorption volume thus to displace an adequate volume of water, is envisaged within the scope of this invention.

It is preferable for the device to be installed within a cistern in its non-absorbed and compact form and then allowed to expand around any obstacles within the cistern. However, as an alternative it may be permitted to expand by the introduction of water prior to installation and then preferably sealed until required for use.

The device as described herein is clearly distinguished from and advantageous over such known devices for a similar purpose including an open bag or vessel adapted to contain but not release a volume of water, or even a building brick or other solid object simply placed in the cistern.

Claims

1. A water displacement device for water storage vessels such as flush cisterns, the device comprising a flexible container within which is provided a material of the kind which is waterabsorbent such as to expand to many times its pre-absorption volume.

2. A water displacement device according to Claim 1, wherein the flexible container is a perforated plastics bag.

3. A water displacement device according to Claim 1, wherein the water absorbent material is a superabsorbent polymer.

4. A water displacement device according to Claim 3, wherein the polymer is a double cross-linked sodium polyacrylate.

5. A water displacement device according to any preceding claim, wherein the container is weighted to enable it to sink in water.

6. A water displacement device according to any preceding claim, wherein the container is a two-compartment plastics bag in one compartment of which there is provided a material which causes it to sink in water, and in the other compartment is the water-absorbent material in the form of a granular polymer.

7. A water displacement device according to any preceding claim, wherein the water-absorbent material is adapted to expand to at least 100 times its pre-absorption volume.

8. A water displacement device according to any preceding claim, wherein the water absorbent material is adapted to expand to 200 times its pre-absorption volume.