AU2002221325B2 - Sediment dispersion device and method - Google Patents

Description

WO 02/48470 PCT/AU01/01591 1 Sediment Dispersion Device and Method Introduction to the Invention This invention relates to the transport and conduiting of fluids through pipes and the like. In particular, the invention relates to mains water piping and to methods and apparatus for modifying the flow of water to minimise the occurrence of sediments accumulating in low flow sections in mains water piping.

Background to the Invention Sediments are a problem in pipes when they accumulate above an acceptable level. An indirect way to measure sediment concentration is through turbidity.

Increases in turbidity can occur when extraneous particulate matter in a fluid source is caused to be disturbed and enter into suspension in the fluid source resulting in cloudiness or manifestation of such particulate matter within the fluid source.

Unacceptable turbidity can occur in any conduiting pipes where a measurable level of impurities occur in the transported fluid.

A particular problem with turbidity occurs when fluid flow rates through a conduit vary such that sedimentary build up of impurities occurs in the bottom of such pipes during times of low flow rate, Any subsequent increase or fluctuation in fluid flow tends to disrupt or dislodge such sediment build ups and results in concentrated blooms of turbidity which interfere with the quality and consistency of fluid supply.

Therefore, whilst most fluid supply systems tolerate a level of impurity in the delivered fluid any inconsistencies of supply are generally much less tolerated as consistency of supply is generally more desirable than absolute purity.

Town water supply is one example of a fluid supply system where the fluid product, being water for general consumption and use, tolerates a measurable level of impurity. Town water supplies generally originate from a natural water source which is stored in dams or tanks and piped to households for use. Such water may be subject to quality control, addition of chemical agents and optionally some filtration. Supplies that are not filtered will contain measurable levels of extraneous particulate matter. Filtered WO 02/48470 PCT/AU01/01591 2 systems, while having lower initial loading of extraneous particulate matter, still accumulate sediments over time. Build up in such systems is due to added chemicals, corrosion and coagulation. The piping system used for town water forms a radiating closed network with pipe size diminishing towards the periphery of the system. Pipe sizes in such systems are designed to cater for consumer needs as well as fire fighting authorities that have access to the same supply system. Fire fighting, although a sporadic occurrence, imposes a very high demand on the water system in excess of general demand. Accordingly, most water piping systems are engineered to cater for such demand where very high water flow may be required. This "over engineering" of the mains water piping means that average day consumption may not impose a high rate of water movement through all of the pipes in a reticulation system. Therefore, the opportunity for sediment to accumulate is escalated. In addition the "closed" nature of the piping system means that water flow is dependent on use rate alone which fluctuates from day to night and season to season. In times of low water use and consequently slow water flow, impurities can fall out of solution and collect as sediment on the bottom of pipes. When water flow increases such sediment are disturbed and results in local areas of high impurity concentration giving rise to "dirLy water" problems. Pipes occurring at the extremities of such reticulation systems, for example in courts and dead ends, are more susceptible to low water velocities and experience more sediment problems.

Another problem area is the region of elbow joints in piping. In particular, elbow joints associated with a vertical section of piping, including fire hydrants, are prone to accumulation of sediment.

To date such problems are addressed by local flushing of mains water pipes or periodic flushing such high maintenance procedures are costly, time consuming, waste considerable quantities of water and are generally only initiated once a problem has occurred.

Similar problems as described for the supply of mains water occur in fluid conduiting systems in other industries.

In order to provide a more consistent water or fluid supply through a conduiting system it would be desirable to average out the concentration of extraneous particulate matter in a fluid source to minimise build up of sediment and sporadic disturbance thereof leading to sporadic escalation in WO 02/48470 PCT/AU01/01591 3 turbidity. However, given the essential nature of mains water supply to the community, any modification of the mains water piping system should limit downtime and interference to the supply.

Statement of Invention In one aspect the invention provides a sediment dispersion device adapted for insertion into a mains water pipe comprising one or a plurality of means for causing water in said pipe to adopt a motion increasing the angular velocity of said water flowing though said pipe wherein said means are sized and configured to allow insertion into said mains water pipe via fire hydrant access points or the like associated with said pipe.

The means for causing water flow in the said pipe to adopt the motion increasing the angular velocity may be a spiral insert. The spiral insert may take the form of a helical screw. The helical screw may be formed as a spiral fin wound about a real or virtual central axle. The central axle is constructed of a length sufficiently short to allow the helical screw to traverse a mains water access point. The mains water access point may include fire hydrants, t-joints, elbow joints and other access points which exist in the mains water piping system.

The sediment dispersion device may comprise a single helical screw unit as previously described including a complete 3600 helix, a partial helix or multiple helicies. The sediment dispersion device may include one or a plurality of previously the described devices which can be connected in series by way of a flexible joint thereby allowing a plurality of devices to be threaded into a mains water pipe in a manner allowing the individual devices to flex around the available access points. The devices can be joined by way of a flexible joint where the flexible joint confers rotational rigidity or potentially confers rotational rigidity between the consecutive devices whilst allowing axial flexibility between consecutive devices. The flexible joint may be a single dimensional pivot clip or may take the form of a universal joint.

Alternatively, the flexible joint can include a flexible line passing through a central hole in the axle of the previously described devices. In this manner, the individual devices can be loosely connected by way of the flexible line so as to allow entry into the mains water piping and once the series of devices have entered the mains water pipe, they can be drawn together by way of the IND 4

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flexible line thereby forming a cooperative series of devices. The ends of the O axles of the devices may be adapted to co-engage upon abutment. The axle Z ends may be provided with dog clutches or similar means allowing engagement of the consecutive devices to ensure control over the rotation of the whole device once installed into the mains water pipe.

IIn order to ensure the inserted device does not rotate within the pipe, a mount may be provided which is adapted for fixing to a free end of the axle of said device and also fitted to the pipe at a convenient point such that rotation r, of the device once installed in the pipe, is prevented.

0 10 The angular velocity of water flowing past the device is preferably generated axially to the primary flow direction of the fluid through the pipe.

The device is preferably passive and adapted for retrofitting to an existing pipe or may be incorporated in the design and manufacture of the pipe or a segment thereof.

The device may occupy the whole cross section of said pipe, or a partial cross-section.

In the case of a partial cross section the helical screw embodiment may be fitted to the inner lining of said pipe as a spiral shaped fin. Alternatively, the helical screw may be positioned at the centre of the pipe. In another aspect a helical screw in the form of a spiral shaped fin may be fitted to the lining of said pipe with a coaxial second pipe passing through the centre thereof to provide circumferential turbulence to said fluid flow whilst ensuring a backup of adequate through flow to cater for fire fighting or other high demands. The helical screw may be formed of any suitable non reactive material including metal, plastic, ceramic, earthenware etc. The fluid may be liquid or gas.

In another aspect the invention provides a sediment dispersion device adapted for insertion into a mains water pipe comprising a plurality of spiral shaped helical inserts joined together in series wherein each insert includes a central axle terminating in a flexible joint adapted for joining consecutive inserts such that said device is sized and configured to allow insertion into said mains water pipe via a fire hydrant access point or the like associated with said pipe and when inserted into said pipe cause water in said pipe to adopt a motion increasing the angular velocity of said water flowing through said pipe.

m:\specifications\500000\501000\501568res1 mawdoc O In another aspect the invention provides a method of reducing sporadic Z high turbidity in a mains water supply pipe comprising introducing a device as previously described into the flow path of water in a mains water pipe so as to cause said water flow to adopt a motion increasing the angular velocity of said water flowing through said pipe on a portion of said pipe.

Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a N stated element, integer or step, or group of elements, integers or steps, but not a 10- the exclusion of any other element, integer or step, or group of elements, integers or steps.

Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application.

Detailed description of the Invention The invention will now be described with reference to Figures 1 to 9 as follows: m:\specifications\500000\501000\501568res1lmawdoc WO 02/48470 PCT/AU01/01591 Figure 1 shows a cut-away view of a section of a pipe having the sediment dispersion device of the invention.

Figure 2 shows the insertion of the device via a mains water pipe insertion point..

Figure 3 shows a flexible joint of the device.

Figure 4 shows an alternative embodiment device of the invention.

Figure 5 shows the insertion of the alternative device.

Figure 6 shows extension tubes used for fitting the device.

Figures 7 and 8 show alternative devices of the invention.

Figure 9 shows a mounting means.

Referring firstly to Figure 1, a particular embodiment of the invention is shown where a fluid transferring pipe 1, which can be adapted for transferring or conduiting any type of fluid including liquid or gas, is of generally circular cross-section. Such fluid transferring pipes allow for the linear transfer of fluid along the length of the pipe with minimal intended turbulence. As detailed in the preamble, such normal piping configurations only allow for a velocity of movement of fluid through the pipe in proportion to demand and the amount and type of movement through the pipe, is limited by such demand and generally linear in the direction of fluid movement. In order to provide an enhanced amount of movement through such a fluid transferring pipe, in addition to the normal linear movement, the invention provides a physical means or device 2 which is adapted for insertion into the pathway of fluid as it traverses the pipe 1. The device 2 most preferably takes the form of a segment of helical screw or spiral 4 which is adapted for insertion into the pipe 1 so as to interrupt fluid flow and cause the fluid to alter its linear flow direction by twisting around and adding a component of angular velocity to the movement of the fluid. This additional rotational moment imposed on the fluid flow, results in increased overall movement of the fluid flow for the passage of a given volume of fluid through the pipe.

Accordingly, the insertion of the device 2 into a fluid transferring pipe causes additional turbulence and movement of fluid that would normally be experienced for a given discharge of water through the pipe. This additional movement and angular velocity imposed on the fluid enhances and assists in the resuspension ability of the fluid to retain any extraneous particular matter in suspension, even when very low demand and discharge of fluid is required from the pipe.

WO 02/48470 PCT/AU01/01591 6 The device can take the form of a solid helical screw 4 having one or more fins 6 dimensioned to fit within the inner lining of the pipe 1. The fin or fins 6 may be adapted to spiral around a central axle 5 thereby causing an impediment to the whole of the fluid flow through the pipe 1.

Referring now to Figure 2 the invention is exemplified as used on a mains water pipe. A typical elbow joint associated with a fire hydrant access point 7 is shown fitted to the terminal end of a mains water pipe 1. The fire hydrant access point provides a ready access means to the mains water pipe without resorting to any interference or work on the mains water pipe per se, thereby eliminating any excavation and prolonged maintenance work. The hydrant access point 7 provides a convenient access to the mains water piping system, however, in order to utilise such an available access point, the curvature of the elbow joint must be traversed or capable of being traversed by the device of the invention in order to allow the device to be installed into the pipe section 1. Accordingly, the helical screw sections 4 are provided in short lengths where each length is sufficiently short to allow traversal of the elbow joint. The flexible joint may take the form of a single or dual pivot mechanism as shown in Figure 3, where the flexible joint 8 can be seen fitted to the end of the axle 5. In this manner, a plurality of helical screw sections 4 can be joined in series and joined in a manner allowing flexibility between individual devices whilst ensuring rotational rigidity is maintained between consecutive devices thereby allowing axial flexibility between consecutive members. In this manner, the device of the invention can be made up of a plurality of helical screw devices joined together in series which can be threaded down the hydrant access point and inserted in to the mains water pipe 1.

Referring now to figures 4, 5 and 6 an alternative embodiment of the device is shown where the flexible joint between consecutive devices is provided as a flexible line 9, adapted for threading through a central hole in the axle 5. The ends of the axles are provided with a dog clutch 11 for cooperation with consecutive devices.

Referring now to figure 5, the installation of this embodiment of the invention is shown where a plurality of devices are threaded down a hydrant access point 7 as a loose assembly of devices connected by way of the flexible line 9. The flexible line allows compliance and movement between the WO 02/48470 PCT/AU01/01591 7 respective devices so as to allow the series of devices to curve around the elbow or other joint and enter the mains water pipe 1.

Referring now to figure 6, the means of installation is further enhanced by the provision of extension tubes 12 which can be used to push the device of the invention further down the mains water pipe 1 to the appropriate position. The extension tubes 12 are of an appropriate length to allow traversal of the elbow or other access points and once the device is suitably installed, it can be held in position by way of a mount shown in figure 9. The mount can be fixed at any point along the pipe but is most conveniently fixed at the interface between the hydrant access 7 and the top of the elbow joint.

In this manner, the housing provides water access through the various apertures 15 and provides a central mount 16 to which the free end of the flexible line 9 or similar attachment can be made.

An alternative embodiment of the helical screw is shown in Figures 7 and 8. Referring to Figure 7, the partial helical screw takes the form of a multiple fin 17 which can be readily inserted into a pipe so as to effect disturbance to the peripheral regions of the pipe whilst allowing the core regions of the fluid flow to pass substantial unimpeded. Figure 8 shows the reverse form of a peripheral fin.

The device of the invention whilst preferably taking the form of a helical screw or Archimedean screw may take the form of other finned means which are sufficient to impart the necessary angular velocity to the fluid flow.

The device can be manufactured out of any non-reactive material including metals, plastics, fibreglass, ceramics etc. The means can be designed for retrofitting to problem areas of piping that are experiencing irregular turbidity. In the example of mains water supply, the means can be inserted into the mains water piping via fire hydrant access.

In use, the invention sees ready application to mains water supply piping where turbidity problems occur, particularly at times of low water use, where sediment can occur at the bottom of piping, for example in dead end streets and courts which experience minimal through flow of water from other users. An example of this application is with a reticulation pipe size of 100mm, which with one user, drawing water from such a pipe, the velocity of water travelling down the pipe is generally in the order of .04 meters per second. It is understood that in such a situation, a water speed of about .4 meters per second is needed to be generated at least once a day in order to WO 02/48470 PCT/AU01/01591 8 keep sediments in suspension. Accordingly, in such a situation, 10 people are required to be drawing water from a 100 millimetre water pipe in order to ensure that sediments do not fall out and subsequently give rise to high levels of intermediate turbidity, thereby causing "dirty water" problems.

With the installation of the means of the invention in a mains water piping system, it has been demonstrated that sufficient angular velocity is introduced into the water flow within the pipe such that the equivalent of only 1 2 people drawing water is sufficient to generate enough movement to ensure that turbidity problems do not occur. In general use, it would be expected that at least two people would be drawing water from a 100 millimetre pipe at least once a day and accordingly the installation of the means of the invention and application of the method of the invention, even in areas of very low velocity locations including courts and dead end streets, is sufficient to provide ample movement to ensure turbidity problems are reduced to a minimum.

The particular modular configuration of the device of the invention provides for the first time the ability to readily install sediment dispersion devices into mains water piping at minimal inconvenience and down time for the mains water piping system. The device of the invention is provided in a short enough length to allow them to squeeze around and traverse the elbow joint at a fire hydrant or t-joints as appropriate using universal joint connections or other flexible means to allow the individual devices sufficient compliance whilst at the same time providing a method of pulling the individual devices together thereby allowing control over the rotational movement of the devices once installed. In practice, devices comprising a single turn of the helical screw and used in lots of three or four tend to provide optimal performance. In order to insert the device of the invention, the fire hydrant access point is exposed by removal of the fire hydrant and a suitable number of the devices of the invention are fed down the hydrant access point into the mains water pipe. In order to move the device away from the elbow, a flexible rod is inserted where each rod has a universal clip or other attachment means thereby allowing the whole assembly to be clipped together on site and fed down the tube. The flexible rod may be of fibreglass or similar construction, or alternatively tightly wound metal spring material with a plastic tubular counter. The device of the invention is preferably made from food grade plastics to reduce and minimise any WO 02/48470 PCT/AU01/01591 9 possible contamination of the water supply. The plastics material is most preferably selected to resist algae build up or the like. The advantages of the invention are many fold, including the economy of manufacture and particularly the economy of installation. The device of the invention is manufactured as a simple snap on or self assembly of the individual devices.

The installation is rapid and requires minimal training and supervision. The device of the invention comprises a minimal number of parts for manufacture and storage thereby minimising maintenance and supply costs. In the event of maintenance being required, the device is readily accessed and removed by reversal of the installation process and once installed, provides a passive means of maintaining an acceptable level of water turbidity in a mains water piping system, thereby preventing the fall out of sediments at times of low water flow.

The invention whilst directly applicable to mains water supply, would be equally applicable to a range of other fluid piping systems, including all manner of liquid chemical transfers and gaseous transfers. Accordingly, whilst the invention has been described with reference to one particularly preferred embodiment, it is not to be seen as limiting to the application to mains water supply.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims (7)

1. 2. A device according to claim 1 wherein said insert is formed as a spiral fin wound about a real or virtual central axle.
2. 3. A device according to claim 1 or 2 wherein said central axle is short enough to allow said helical screw to traverse said mains water access point.
3. 4. A device according to any one of claims 1 to 3 wherein said flexible joint confers rotational rigidity between consecutive inserts while allowing axial flexibility between consecutive inserts. A device according to any one of claims 1 to 4 wherein said flexible joint is a universal joint fitted to the ends of said central axle.
4. 6. A device according to claim 5 wherein the ends of said axles are provided with dog clutches to effect said co-engagement.
5. 7. A device according to any one of claims 1 to 6 further including a mount adapted for fixing a free end of said axle relative to said pipe to prevent isolation of said device once inserted into said pipe.
6. 8. A method of reducing sporadic high turbidity in a mains water supply pipe comprising introducing a device according to any one of claims 1 to 7 into the flow path of water in a mains water pipe so as to cause said water flow to adopt a motion increasing the angular velocity of said water flowing through said pipe on a portion of said pipe and reducing the accumulation of particles from the water in said pipe.
7. 9. A device according to any one of claims 1 to 7 substantially as hereinbefore described with particular reference to the figures. A method according to claim 8 substantially as hereinbefore described. Dated this fifteenth day of November 2006 m:\specifications\500000\501000\501568res1 mawdoc