AU741090B2

AU741090B2 - Improvements in or relating to water supply

Info

Publication number: AU741090B2
Application number: AU48926/00A
Authority: AU
Inventors: Kelvin Denis Thomas
Original assignee: Yarra Valley Water Ltd
Current assignee: Yarra Valley Water Ltd
Priority date: 1999-07-30
Filing date: 2000-07-31
Publication date: 2001-11-22
Anticipated expiration: 2020-07-31
Also published as: AU4892600A

Description

t P/00/01 1 Regulation 3.2

AUSTRALIA

Patents Act 1990 lP Australia Documnents receiv ed on' 2 4SEP 200 1

NO:D

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Improvements In Or Relating To Water Supply Invention title: The following statement is a full description of this invention, including the best method of performing it known to us: WM 1l1073449202304600819 19.09.2001 IMPROVEMENTS IN OR RELATING TO WATER SUPPLY Field of the invention The present invention is directed to improvements in or relating to water supply, and more particularly but not exclusively to improvements to methods and apparatus for modifying the flow of water to a facility through a pipe network.

Background of the invention In this specification, where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was at the priority date: ooooo S 10 part of common general knowledge; or S: (ii) known to be relevant to an attempt to solve any problem with which this specification is concerned.

.:The supply of, and access to, potable water at acceptable water pressure is seen as a right by many if not all water consumers, be they private house dwellers or commercial 15 customers. However, the contract between the water service provider and the consumer ooo.

requires certain obligations to be fulfilled on the part of the consumer. In return for the continuous supply of potable water at an acceptable pressure, the consumer pays the water service provider on account within a time limit set by the provider. The amount payable is nowadays generally linked to the amount of water usage according to the "user-pays" S 20 principle. A contribution is also usually made for sewerage, sewerage disposal and drainage.

At times, financial hardship means that some customers find it difficult to pay their water account in a timely manner. Allowance is as a general rule made by the water service provider for such financial hardship, and an agreed payment plan may be implemented between the water service provider and the customer in such circumstances. It has been observed however that there is a certain class of customer who, notwithstanding a financial ability to pay the water supply account in a timely manner, elects for whatever reason not to pay the account. In such circumstances, the water service provider has fulfilled its part of the contract but the customer has breached the contract by declining to pay the account.

In these circumstances, the water service provider is entitled to restrict the flow of water entering the customer's facility. The traditional method used to restrict the flow of Swater to the customer is by turning the isolating stop valve on the stop tap to the facility to tvim MO110734492v2 304600819 19.9.2001 only enable a significantly reduced water flow rate. A box is then placed over the stop tap and the box padlocked in place.

It will be readily appreciated that the belligerence of such customers means that in many cases attempts are made to remove the box fitted over the stop tap. In the case of a padlock, this can be a relatively simple task for a determined person, who can break the padlock such as by the use of a metal saw or a hammer and can then remove or lever the box away from around the stop tap to gain access to the stop tap. The water supply can then be simply resumed by turning the stop tap to re-open the stop valve.

Whilst damage to equipment in this way is a prosecutable offence, it will be S10 appreciated that the relative ease with which a determined person can resume the water oo supply, notwithstanding the attempt by the water service provider to restrict the flow of water to the customer, can be of serious concern to the water service provider, and such a practice has the potential to cause economic loss to the water service provider.

Summary of the invention The present invention accordingly provides in one embodiment a method for restricting the flow of water to a facility through a water service pipe, the method comprising the steps of temporarily stopping the flow of water to the facility through the water service pipe by freezing water in said water service pipe, introducing flow restriction means into part of the pipe to reduce the cross-sectional area available for the passage of water through that o o 20 part of the pipe, and resuming the flow of water to the facility through the pipe by unfreezing S* water in said pipe, wherein the flow of water to the facility following resumption is restricted by the flow restriction means as compared to the flow of water to the facility in the absence of said means.

The flow of water may be temporarily stopped in any suitable manner. In one presently preferred embodiment the flow stream is temporarily frozen using liquid nitrogen.

Other arrangements for temporarily stopping the flow of water are envisaged within the scope of the invention.

The water service pipe may be part of a pipe network.

The step of introducing the flow restriction means preferably comprises securing the restriction means to the pipe so as to resist removal of the restriction means from the pipe.

The present invention provides in another embodiment a method for modifying a tap having a pipework connection to restrict the flow of water to a facility through the tap, the tvlmMO110734492v2 304600819 19.9.2001 method including the steps of temporarily stopping the flow of water to the tap by freezing water to the tap, removing the pipework connection from the tap, inserting flow restriction means into the flow stream, and resuming the flow of water to the facility by unfreezing water to said tap, wherein the flow of water to the facility following resumption is restricted by the flow restriction means as compared to the flow of water in the absence of said means.

10 In one arrangement of this embodiment the flow restriction means may be inserted into the pipework in the region of its connection with the tap and secured so as to resist its removal from the pipework. In this embodiment the flow restriction means may extend at 99 least partly into the tap. In another arrangement of this embodiment the flow restriction means may be inserted into part of the tap.

The isolating stop valve of the stop tap may be removed from the chamber of the stop tap to facilitate the positioning of the flow restriction means. Once the restriction means has been positioned the stop valve may be returned to the chamber of the stop tap.

In one particularly preferred embodiment, pipework on an upstream side of the isolating stop valve of the stop tap is frozen using liquid nitrogen and the stop valve is 20 removed from the stop tap chamber. In one arrangement of this embodiment, the flow S" restriction means is inserted into the pipework and seated in a flange of the pipe. The stop valve is then reconnected and the water supply unfrozen. This procedure may be reversed to remove the flow restriction means from the pipework.

The present invention provides in another separate embodiment a method for modifying a tap having a pipework connection to restrict the flow of water to a facility through the tap, the method including the steps of temporarily stopping the flow of water to the tap along pipework on an upstream side of the tap, removing the pipework connection from the upstream side of the tap, inserting flow restriction means into the flow stream on the upstream side of the tap, and resuming the flow of water to the facility, wherein the flow of water to the facility following resumption is restricted by the flow restriction means as compared to the flow of water in the absence of said means.

tvlm MO110734492v2304600819 19.9.2001 A consequence of the introduction of flow restriction means in accordance with the invention is that the water pressure to the facility is significantly less than normal mains pressure or an otherwise agreed acceptable pressure provided to the facility by the water service provider in the absence of the flow restriction means. The degree of restriction of water flow to the facility is preferably significant. In one preferred embodiment the water flow is reduced to a minimum flow rate of 2 litres per minute as measured at the nearest tap to the water meter. This translates approximately to the customer's ability to fill and flush their toilet twice a day and fulfils health requirements, but is insufficient to comfortably undertake a domestic activity which requires significant water pressure such as the taking of a shower, the 10 filling of a bath or the watering of a garden.

o0 o:o ~The present invention provides in another separate embodiment flow restriction means capable of being inserted into a pipe on the pressure side of the pipe, the flow restriction means including a body portion and positioning means for positioning the flow oo °restriction means in the pipe by an interference fit, the arrangement being such that when 15 inserted in the pipe the flow of water on a downstream side of the flow restriction means is significantly less than the flow of water to the flow restriction means at an upstream side of oro o S"the flow restriction means.

The present invention provides in another separate embodiment flow restriction oo means capable of being inserted into a pipe, the flow restriction means including a body 20 portion having a passage therein and positioning means for positioning the flow restriction 0 means in the pipe, the arrangement being such that when inserted in the pipe the flow of water on a downstream side of the flow restriction means is significantly less than the flow of water to the flow restriction means at an upstream side of the flow restriction means.

The present invention provides in another embodiment a stop tap to which is connected a pipe having flow restriction means as disclosed.

The present invention provides in another embodiment a stop tap including flow restriction means as described.

Flow restriction means according to the present invention may take any suitable form.

The flow restriction means is preferably positioned near the stop tap of the pipe network or water service pipe to the facility. In a particularly preferred embodiment the flow restriction means is positioned on an upstream side of the stop tap, that is, on the mains side of the stop tap. The flow restriction means is preferably seated in a flange of the water service pipe in the STk region of its normal connection to the stop tap at an upstream side of the tap. The tvlm MO110734492v2304600819 19.9.2001 connection between the stop tap and the pipe is typically a screw-threaded connection, the internal thread of the pipe flange engaging with an external thread on the upstream side of the tap. A locking nut or other locking arrangement may be provided to establish a secure connection between the pipe flange and the tap.

The flow restriction means may extend at least partly into the stop tap in the region of its connection with the flange of the pipe. Preferably the arrangement is such that the flow restriction means has positioning means which seats in complementary fashion in the flared end of the pipe.

For larger diameter pipes, the stop tap may be spaced from the water meter. The stop 99 10 tap may for larger diameter pipes be replaced by a gate valve.

The flow restriction means may be in the form of a plug. The plug may provide a narrow annulus around which only a small volume of water may flow into the valve chamber o of the stop tap. In this way the amount of water available for discharge by the stop tap to the downstream side of the tap is severely curtailed even if the stop tap valve is full open.

The passage of the flow restriction means may include a bore. The bore may be 9 narrow. In this embodiment the arrangement is such that only a significantly reduced volume of water may pass through the narrow bore. The diameter of at least part of the bore is preferably significantly less than the diameter of the water service pipe in which the flow restriction means is positioned. The bore may be a substantially central bore extending 20 through the body portion of the flow restriction means.

The passage may include a chamber in which a reducer can be positioned. The reducer may be removable. The reducer may be in the form of a grub screw. The grub screw may be capable of being removed from the chamber by means of a tool such as an allen key or similar tool. In one embodiment the passage comprises a chamber of sufficient dimension to receive a reducer in the form of a grub screw and a narrow bore at one end of the chamber.

It will be apparent that belligerent customers may seek to tamper with the flow restriction means according to the invention with a view to removing, modifying or destroying the restriction means and thereby resuming the water flow at increased or approximately normal volumes and pressures. Accordingly in a further embodiment securing means is provided to secure the flow restriction means to the pipe and/or to the stop tap so as to resist removal of the restriction means. The arrangement is such that removal of the flow restriction tvlm MO110734492v2304600819 19.9.2001 means from the flange and/or the stop tap is resisted in cases where a tool such as a spanner or screwdriver may be used to try and remove the flow restriction means from the pipe or tap.

The arrangement is preferably such that the restriction means can only be removed using a security key of a predetermined configuration. The flow restriction means may accordingly include a keyway corresponding to the predetermined configuration of the security key. The keyway is typically provided on an inner surface of an aperture extending through the restriction means. Where the restriction means is secured to the flange of a pipe in the region of the upstream edge of the stop tap, access to the keyway may be through the chamber of the stop tap. In this embodiment the stop valve is removed from the chamber to gain access to the keyway by the security key.

o The security key may take any suitable form. It may be in the form of a key having a shape generally approximating that of a normal access key to engage with the keyway of the 0o restriction means. It may be elongated. In another embodiment it may comprise a tool such as an allen key or other tool such as a screwdriver having an engaging portion adapted to engage with the keyway of the restriction means. In one particularly preferred embodiment the security key has a predetermined thread arrangement capable of mating with a corresponding thread on the flow restriction means whereby the application of the key to the °ooo flow restriction means permits the flow restriction means to be removed from the pipe flange.

•o ooo The security key may also be provided to ensure that a technician's fingers do not a 20 contact the pipe directly in cases where the pipe is frozen for the purpose of temporarily stopping the water supply.

Brief description of preferred embodiment The invention will now be described with reference to a particularly preferred embodiment.

In the drawings, in which like integers are given like reference numerals: Figure 1 is a schematic elevation of a water meter assembly having a stop tap arranged on the mains side of the meter; Figure 2 is a part cross-sectional elevation of a stop tap having flow restriction means according to one embodiment of the invention inserted in a pipe connected thereto; and Figure 3 is a cross-sectional elevation of the flow restriction means of Figure 2.

tvlm MO11O734492v2304600819 19.9.2001 Turning to the drawings, Figure 1 shows generally a source of mains water 10 supplied via pipework 11 through a stop tap 12 and metering assembly 13 to pipework 14 for a facility (not shown). Pipework 14 in the embodiment shown passes under the ground 15 to the facility to supply potable water at or near mains pressure or at an agreed acceptable pressure.

Stop tap 12 includes a stop valve chamber 16 and a stop valve 17 of a configuration as is known in the art. Stop tap 12 includes at an upstream side thereof an externally threaded member 18 adapted to engage a corresponding internal thread carried by the flange 21 of pipe 11. A locking nut 19 or other locking arrangement may be provided on the outside of the tap/pipework connection to assist in securing the pipe 11 to the stop tap 12.

Flow restriction means 20 in the form of a plug having a flared end approximately corresponding to the shape of flange 21 and having a narrow central bore 22, is seated in the •flange 21 of pipe 11. In the embodiment shown in Figure 2, flow restriction means p°°4° extends at least partly into the stop tap 12 past the end 23 of stop tap 12.

o :66 A chamber 24 in the passage of flow restriction means 20 is provided. Chamber 24 is capable of receiving a reducer such as a grub screw removable from the chamber 24 only by the use of a tool such as an allen key so that the technician's fingers don't come into contact with a frozen pipe (see below) when installing the flow restriction means In use, once it has been established that a customer refusing to pay a water supply account has the financial ability to pay, a technician is dispatched to the customers facility.

600 20 The flow of water from the mains connection through pipe 11 is temporarily stopped by providing a source of liquid nitrogen and freezing the pipe 11 and hence the water contained therein. This can be accomplished such as by making a clay pot around the pipe on the pressure side of the pipe and pouring liquid nitrogen into the clay pot, following which the water flow stops.

Stop valve 17 of stop tap 12 is removed from its chamber and the pipe connection between stop tap 12 and pipe flange 21 is disengaged by loosening and/or removing locking nut 19 to gain access to the flange 21. The flow restriction means 20 is inserted into the pipe 11 in the region of flange 21 and a grub screw inserted into chamber 24 of the flow restriction means 20 to secure the flow restriction means 20 to the end 23 of the stop tap 12. Once this has been effected, stop valve 17 is reinserted into chamber 16 and the pipework connection re-established. Pipe 11 is unfrozen such as by pouring water over the pipe in the frozen region so that the water temperature returns to a temperature approaching ambient, and the Twater supply resumed.

tvlm MO110734492v2304600819 19.9.2001 By virtue of the very narrow bore 22 in flow restriction means 20, a significantly reduced volume of water at a significantly reduced pressure passes from bore 22 into chamber 16 of stop valve 12. Even with the stop valve 17 fully open, the flow of water to downstream pipe 14 is significantly reduced compared to the flow of water in the absence of the flow restriction means 20. In this way, the volume and the pressure of water available to the customer is significantly reduced.

The word 'comprising' and forms of the word 'comprising' as used in this description and in the claims does not limit the invention claimed to exclude any variants or additions.

Modifications and improvements to the invention will be readily apparent to those skilled in the art. Such modifications and improvements are intended to be within the scope of this invention.

S* t S.e So

S.

tvim M0110734492v2 304600819 19.9.2001

Claims

1. A method for restricting the flow of water to a facility through a water service pipe, the method comprising the steps of temporarily stopping the flow of water to the facility through the water service pipe by freezing water in said water service pipe, introducing flow restriction means into part of the pipe to reduce the cross-sectional area available for the passage of water through that part of the pipe, and resuming the flow of water to the facility through the pipe by unfreezing water in said pipe, wherein the flow of water to the facility following resumption is restricted by the flow restriction means as compared to the flow of water to the facility in the absence of said means.

2. A method according to claim 1 wherein the water is frozen using liquid nitrogen.

3. A method according to claim 2 wherein said freezing of the flow of water comprises forming a clay pot around the pipe on the pressure side of the pipe and pouring the liquid nitrogen in to the clay pot. 15

4. A method according to any one of claims 1 to 3 ,wherein said flow restriction means is secured to the pipe so as to resist removal of the restriction means from the pipe.

A method for modifying a tap having a pipework connection to restrict the flow of water to a facility through the tap, the method comprising the steps of temporarily stopping the flow of water to the tap by freezing water to the tap, removing the pipework connection from the tap, inserting flow restriction means into the said tap, and resuming the flow of water to the facility by unfreezing water to said tap, wherein the flow of water to the S•facility following resumption is restricted by the flow restriction means as compared to the flow of water in the absence of said means.

6. A method according to claim 5 wherein the water is frozen using liquid nitrogen.

7. A method according to claim 6 wherein said freezing of the flow of water comprises forming a clay pot around the pipe on the pressure side of the pipe and pouring the liquid nitrogen in to the clay pot.

8. A method according to any of claims 5 to 7, wherein said pipework connection is on an upstream side of the tap. tvim MO110734492v2304600819 24.9.2001

9. A method according to claim any one of claims 5 to 8, wherein said flow restriction means is inserted into the pipework in the region of its connection with the tap and secured to resist removal from the pipework.

A method according to any one of claims 5 to 9, wherein said flow restriction means when inserted into said flow stream extends at least partly into the tap.

11. A method according to any one of claims 5 to 10, wherein said flow restriction means is inserted into part of the tap.

12. A method according to any one of claims 5 to 11, wherein said flow restriction means is introduced into the flow stream by removing the tap valve of said tap from the tap chamber of said tap, inserting said flow restriction means into said chamber, and re-placing said valve in said chamber.

13. A method according to any one of claims 1 to 12, wherein said flow restriction *".means is inserted into said flow stream and seated in a pipe flange.

14. A method for restricting the flow of water to a facility through a water service 15 pipe, substantially as hereinbefore described and with reference to any one of the accompanying drawings.

A method for modifying a tap having a pipework connection to restrict the flow of water to a facility through the tap, substantially as hereinbefore described and with reference to any one of the accompanying drawings.

16. A flow restriction means capable of use in the method of any one of the preceding claims, said flow restriction means comprising a body portion and positioning i means for positioning the flow restriction means in the pipe or tap.

17. A flow restriction means according to claim 16, wherein said body portion has a passage for the flow of water.

18. A flow restriction means according to claim 17, wherein said passage comprises a bore for the flow of water through the bore.

19. A flow restriction means according to claim 17, wherein the diameter of at least part of the bore is less than the diameter of a pipe in which the flow restriction means is positioned.

20. A flow restriction means according to any one of claims 16 to 19, wherein said S restriction means is positioned in said pipe by an interference fit. tvim M0110734492v2 304600819 19.9.2001 11

21. A flow restriction means, substantially as hereinbefore described and with reference to any one of the accompanying drawings. YARRA VALLEY WATER LTD 19 September, 2001 S* S S SS** S S S S.. S S S 55 S S tvlm MO11O734492v2 304600819 19.9.2001