GB2348195A

GB2348195A - Fluid treatment

Info

Publication number: GB2348195A
Application number: GB9921237A
Authority: GB
Inventors: Christopher Michael Dav Joslin; John Christopher Suth Buchanan
Original assignee: Ion Enterprises Ltd
Current assignee: Ion Enterprises Ltd
Priority date: 1999-03-24
Filing date: 1999-09-08
Publication date: 2000-09-27
Also published as: GB9921237D0

Abstract

At least partial precipitation and removal of solute compounds within a fluid without the use of chemicals is achieved by a fluid treatment systems that includes a fluid inlet 3 for the fluid to be treated, a fluid reservoir 1, a fluid output 20 for treated fluid and a feedback path. The feedback path has an exit 18 from the fluid reservoir, an entrance 17 to the reservoir, and includes a purgeable filter 8 for removing solids from the feedback path, a physical fluid conditioning device 12 for causing solutes in the fluid to be precipitated from the fluid and a pump 14 for circulating the fluid through the feedback path. The physical fluid conditioning device may be an electromagnetic system, an electrostatic system, an a.c. pulse system, a permanent magnet system or a galvanic system. The use of ion supplying means is also discussed.

Description

FLUID TREATMENT The present invention relates to fluid treatment systems, in particular fluid treatment systems employing physical conditioning devices.

Physical Water Conditioning devices (PWC's) exist in several forms, the most common of which are: electromagnetic systems; electrostatic systems; a. c. pulse systems; permanent magnets systems; galvanic systems.

The main purpose, or at least as claimed by the various manufacturers of PWC's, is to change the characteristics of the scale forming compounds present in the water and thereby reduce the detrimental effects of hard scaling that takes place thereafter within water systems. Examples of such water systems are: hot water circulating systems; air conditioning or refrigeration cooling tower systems; steam producing boiler plants.

In exceptionally hard water situations it has been normal in the past to resort to chemical treatment, especially using ion exchange units. However, in the light of current environmental impact considerations around the world and the fact that ion exchange units release sodium chloride salts into the effluent, a means of reducing water hardness more efficiently by non-chemical methods would be considered desirable.

PWC devices are regularly used in circulating water systems whereby in-line strainers, hydrocyclonic separators and filters are also typically included. This well established practice of filtration is intended to trap and remove any particles of breakaway scale and the build-up of accumulated suspended solids in recirculating systems such as cooling towers and hot water systems. However, soluble compounds under these circumstances tend to remain within a circulating system and continue to give rise to unacceptable levels of scaling problems within pipe-lines and heat exchangers, heating surfaces within appliances, etc.

Simply providing an in-line filter in order to remove hardness is typically an unsatisfactory arrangement as a filter medium provides only for the temporary collection of, for example, precipitated calcium carbonate (CaC03), which could subsequently dissolve back into solution within the water stream. Hydrocyclonic separators are incapable of effectively separating precipitated CaC03 from a body of water due to being similar in density to water.

Accordingly, an aim of the present invention is to provide for more effective removal of dissolved or suspended particles from a fluid such as water.

In accordance with one aspect of the invention, there is provided a fluid treatment system for reducing dissolved compounds in fluid to be treated, the fluid treatment system comprising a fluid inlet for fluid to be treated, a fluid reservoir, a fluid output for output of treated fluid, and a feedback path having an exit from the fluid reservoir and an entrance to the reservoir, the feedback path including a purgeable filter for removing solids from the fluid feedback path, a physical fluid conditioning device for causing dissolved solids in the fluid to be precipitated from the fluid and a pump for circulating the fluid through the feedback path.

In accordance with another aspect of the invention, there is provided a method of reducing solutes in a fluid to be treated, the method comprising steps of filtering precipitated solutes and causing solutes to be precipitated in multiple passes through a feedback path which extends from and to a reservoir for the temporary storage of the fluid.

Although in a preferred embodiment, the fluid to be treated is water containing solutes therein to be precipitated and removed, in other embodiments the fluid to be treated can be any fluid body having solutes therein to be precipitated and removed.

An embodiment of the invention seeks to provide an acceptable level of water softness, by significantly reducing the actual level of hardness present in a fluid such as water, without the disadvantages of chemical treatment.

The fluid to be treated may also be a fluid which contains tiny particles held in suspension, for example, a colloidal suspension so that by the same process these particles may be flocculated or coagulated in order that they shall become filtrable enabling their removal from the fluid to be treated.

In an embodiment of the invention, the reservoir holds a body of partially treated water.

An embodiment of the present invention could be described as an electromechanical softener (EMS).

In the following, an exemplary embodiment of the invention will be described with reference to the accompanying figure.

Figure I illustrates, by way of example, an EMS forming an embodiment of the invention. This embodiment provides a fully integrated fluid treatment system, which includes a, preferably enclosed and preferably cylindrical, reservoir 1, a three-port head 2, an untreated water inlet pipe-line 3, a first non-retum valve 4, a fluid flow sensor 5, an automatic air-vent release valve 6, a fluid pressure gauge 7, a back-flushing filter 8, a time pressure differential operated purge valve 9, a pipe-line 10, a first coiled pipeline 11, a Physical Water Conditioner (PWC) 12, a second coiled pipe-line 13, a water pump 14, an ON/OFF pump controller 15, a pipe-line 16, a circulation outlet pipe-line 17, a riser pipe-line 18, a second non-return valve 19, a treated water outlet pipe-line 20 and a bonded bridge earth wire 21 to ground 22. The EMS can be contained within a housing (not shown).

The reservoir, multi-port head, pipe-lines and other components can be formed from suitable materials such as plastics, metals and fibreglass materials. In a preferred embodiment, the reservoir and the pipe-lines are made of a material such as copper, and the multi-port head is made of a metal such as brass. However, other metals and/or plastics materials could be used as appropriate. With particular reference to the physical conditioner, it is preferred that the pipelines either side are made of a metal.

The choice of the metals used should take into account the materials used in the physical conditioners to ensure that they do not impact the operation of the physical conditioner. For example, if a physical conditioner such as the Scalebuster PWC referred to later is used, which employs brass and zinc in its construction, then suitable metals for the pipework and the cylinder would, for example, be copper or iron.

Untreated water enters the EMS via the inlet pipe-line 3 at a point"A"on only three possible occasions during its operation; that is, immediately upon the demand for treated water via the outlet pipe-line 20 at a point"B"or immediately upon the filter purging to waste via the filter outlet at point"C"or upon the demand for treated water and the purging of waste taking place simultaneously.

The untreated water upon entering the EMS by the inlet pipe-line 3 passes through the first non-return valve 4 and the flow sensor device 5 before joining the circulating loop system at a junction where the riser pipe-line 18 is met.

Water undergoes softening treatment by circulating either continuously or for set periods of time through a feedback path with the aid of the pump 14, passing via the pump outlet pipe-line 16, through one of the ports in the three-way head 2, through a tangentially located pipe-line 17 within the reservoir cylinder 1. The tangentially swirling water dynamically enables the previous water flow to fulfil one of two requirements. Firstly, to exit the reservoir cylinder at one of the ports in the three-way head 2 as softened water when under demand for its further use or consumption and/or secondly, the previous water flow is caused to enter the riser pipe-line 18 located centrally and relatively close to the internal base of the reservoir cylinder. This particular water flow is confined to a one-way loop circulation through the feedback path until it reunites with the main body of water within the reservoir.

In this feedback path, the flow passes through the riser pipe-line 18 and the second non-return valve 9, joins any possible incoming untreated water at a junction along the inlet pipe-line 3, passes the automatic air-vent release valve 6, and then passes through the back-flushing filter 8, the filter outlet pipe-line 10, the first coiled pipe-line for water cooling purposes 11, the PWC 12, the second coiled pipe-line for water cooling and the precipitation of solutes 13 and the pump 14 and then passes back into the reservoir cylinder 1 at point"D"via pipe-lines 16 and 17.

The degree of precipitation can be controlled by adjusting the average number of passes that the water makes through the feedback path. This can be controlled, for example by setting the volume of circulating fluid to exceed the demand volume of treated fluid by an appropriate degree, with the size of the reservoir being calculated taking into account the desired demand, pump flow rates and pressure considerations.

The percentage of water which recycles through the feedback path versus being drawn off at the outlet B can be adjusted by suitable dimensioning of the reservoir 1 and the dimensioning and positioning of the pipes 17,18 and 20 with respect to the reservoir 1, It will be noted that the circulation outlet pipe 17 is set to follow the circumference of the reservoir 1 to encourage a circulating flow within the reservoir. In this regard, it is preferable, but not essential, that the reservoir 1 is cylindrical. This provides efficient mixing of the water from the feedback path with that already in the reservoir 1, thus improving the efficiency of treatment. The open end of riser pipe 18 is located well spaced from the circulation outlet pipe 17 around the central part of the bottom of the reservoir 1 in order that the water taken from the reservoir 1 to be passed via the feedback path has been well mixed. The riser pipe 18 rises substantially along the vertical axis of the reservoir 1. The volume of the reservoir should be chosen with respect to the desired demand volume such that on average the water is caused to recycle via the feedback path at least once, and preferably a plurality of times, in order to achieve a desired degree of softening of the water with removal of the precipitated solutes via the purgeable filter 8. In other words, the volume of circulating fluid should be chosen to exceed the demand volume of treated fluid by at least once.

The PWC adopted within the present EMS is preferably, but not exclusively, a PWC marketed under the names ISB and SCALEBUSTER as per European Patent No.

EP-B-680,457. Scalebuster and ISB are trademarks of Ion Enterprises Limited. Tests conducted by Cranfield University's Water Sciences Department have conclusively demonstrated the ability of the Scalebuster PWC consistently to precipitate solutes of calcium in abundance. The Scalebuster PWC has a brass body forming a fluid inlet, a fluid outlet, and a cavity extending between the inlet and the outlet. One or more dielectric channel separators (preferably of plastics material, more preferably PTFE) is located in the cavity between the inlet and the outlet and extends at least part way along the cavity. The dielectric channel separator divides the cavity into a plurality of elongate channels which are mutually coextensive for at least part of their length in the direction of fluid flow from the inlet to the outlet and are at least partially bounded by dielectric material. One or more metallic channel separators, preferably of zinc, are also provided to form a sacrificial anode to provide a degree of protection against corrosion. Each metallic channel separator can include one or more of elongate channels which are mutually coextensive for at least part of their length in the direction of fluid flow from the inlet to the outlet. Adjacent channel separators are configured to encourage turbulence in the fluid flowing through the device to enhance the precipitation of solutes.

If required, for example if the PWC does not incorporate a zinc anode or its equivalent, at least one independent sacrificial anode of an appropriate material (e. g., zinc) can be located within the fluid stream if thus considered appropriate in order to provide a desired degree of protection against corrosion. As an alternative, or in addition to a sacrificial anode, alternative methods can be used for providing appropriate ions (e. g. zinc ions). Thus, for example, means for the controlled injection of a zinc or zinc ion bearing solution, or the use of zinc or zinc ion bearing tablets which slowly dissolve, could be provided.

The back-flushing filter 8, which can be of conventional construction, is caused to operate at regular intervals (e. g. once per hour, although another interval could be used) by opening the purge valve 9. The purge valve 9 could alternatively, or in addition, be operated by a signal from a pressure differential sensor (not shown) indicating that a predetermined degree of blocking of the filter has occurred. The back flushing filter and purge valve form one suitable form of purgeable filter. Another form of purgeable filter arrangement could be used, as long as the filter arrangement is able to remove precipitated solutes from the body of water to be treated. The filter medium in the purgeable filter is chosen, in accordance with well understood principles, such as filter size, materials, etc., to be appropriate to enable the required precipitates to be separated from the main body of the fluid. The automatic backflushing filter could be either substituted by or complimented with at least one cartridge type filter for a semi-automatic mode of operation.

The EMS uniquely combines the PWC together with the back-flushing filter so that the volume of circulated water exceeds that of the volume drawn off for consumption or further use together with the incidental purges from the filter to waste.

This ensures repeated subjection of the water to treatment and a further reduction of the compounds in solution to further soften the water. The filter back-flushes at specific intervals so as to remove the majority of precipitated compounds before the water stream re-dissolves it back into the main body of the water.

In order to enhance precipitation of CaC03, a bonded earth wire 21 is provided to bridge the PWC and a substantial length of each of the coiled pipe-lines 10 and 12.

The bridge wire should preferably but not exclusively be connected to a quality grounding, in the order of < I ohm.

The pump 14 is switched on and off by the controller 15 that is activated by the flow sensor 5 and/or by a softness sensor so that the pump operates during any demand for treated water and for a set period of time thereafter of, for example, ten minutes before switching off after a period of there being no demand for treated water. Further tests will be required in order to simply determine the optimum flow rate and reservoir capacity to suit the demand and softness of the treated water.

The possibility remains for a second PWC (not shown on the drawing) to be located at the beginning of or along the length of the riser pipe-line 18 within the reservoir to act as a booster to the treatment, if this is considered necessary.

Although the described embodiment can be fully integrated within a single housing and thereby form a compact appliance, it may suit on occasions to adjust the arrangement. Thus, for example, any number of the components of the appliance could be spaced apart so that the whole is not confined to a single housing. For example, a header tank within a building may replace that of the reservoir cylinder of the EMS. This is but one example of a case where the reservoir is located separately from the physical conditioner and the purgeable filter and where the reservoir could be open to atmosphere, rather than being enclosed.

Finally, compounds other that CaCO3 solutes, such as soluble iron can be successfully precipitated, filtered and subsequently purged to waste in order to clarify water. This aspect should be of particular interest in a country like Japan that suffers from what is called Red Water Syndrome. The EMS can also incorporate UV treatment and chlorine reducing filter mediums into the system that remains contained.

Also, although in the particular embodiment described, the EMS is operable to treat and reduce the hardness of water, the apparatus could also be used to treat dissolved chemicals in other liquids and fluids, subject to the provision of a suitable physical conditioning device in the feedback path, or other means of adding zinc ions.

Thus, there has been described an embodiment of the present invention that seeks to provide a means to achieve at least partial precipitation of solute compounds within fluids and its subsequent removal from the main body of the fluid without the use of chemicals, whereby there is provided an untreated fluid inlet, a treated fluid outlet and a precipitated concentrates outlet, the inlet pipe-line section having a nonreturn valve and a fluid flow sensor, interconnecting with another section comprising an enclosed reservoir with a sealed multi-port head, a loop pipe-line flow system that incorporates, in the direction of the flow, a riser pipe-line from within the reservoir, a non-return valve, an automatic air-vent, a pressure gauge, a back-flushing filter, a timer/pressure differential operated purge valve, coiled pipe-lines encompassing a PWC, a bonded electrical earth wire bridging the PWC together with a substantial length of each of the coiled pipe-lines, a pump, an ON/OFF pump controller and a pipe-line to complete the loop back into the interior of the reservoir, the termination of the inner pipe-line being open and located so that the returning flow is preferably but not exclusively tangential to create a vortex and that the volume of the circulating fluid exceeds the demand volume for the treated fluid by at least once.

Although a specific embodiment of the invention has been described, it will of course be appreciated that the invention is not limited thereto and that many modifications, substitutions, additions and deletions with respect to the specific embodiment may be made within the scope of the invention.

For example, although the inlet pipe-line 3 leads to a function with the riser pipe-line 18, in the described embodiment, the inlet pipe-line could join with the feedback path at another point, or indeed be fed directly into the reservoir, for example if a further PWC is included in the inlet pipe-line. Also, although a particular sequence of elements is shown in the feedback path, another order or constitution of elements may be provided. For example, the PWC 12 could precede the back-flushing filter 8.

Also, for example, a purgeable filter can form the last component within the flow stream. For example, such a purgeable filter could be in the form of a backflushing sand-filter (e. g., in an embodiment forming a water treatment works) whose main function would be to remove flocculated colloids from the water flow as a final "polishing"treatment.

Claims

CLAIMS 1. A fluid treatment system for reducing solutes in fluid to be treated, the fluid treatment system comprising a fluid inlet for fluid to be treated, a fluid reservoir, a fluid output for output of treated fluid, and a feedback path providing an exit from the fluid reservoir and an entrance to the reservoir, the feedback path including a purgeable filter for removing precipitated solutes from the fluid feedback path, a physical fluid conditioning device for causing solutes in the fluid to be precipitated from the fluid and a pump for circulating the fluid through the feedback path.
2. A fluid treatment system according to Claim 1, wherein the fluid to be treated is water to be softened.
3. A fluid treatment system according to Claim 1 or Claim 2, wherein the physical conditioner is selected as one or more of : an electromagnetic system; an electrostatic system; an a. c. pulse system; a permanent magnet system; a galvanic system; ion bearing tablets; and means for injecting ion bearing solutions.
4. A fluid treatment system according to any preceding Claim, wherein a sacrificial anode is located within the fluid stream.
5. A fluid treatment system according to any preceding Claim 3, wherein the physical conditioner comprises a zinc anode.
6. A fluid treatment system according to any preceding Claim 1, wherein the volume of circulating fluid exceeds the demand volume of treated fluid by at least once.
7. A fluid treatment system according to any preceding Claim, comprising a further physical conditioner.
8. A fluid treatment system according to any preceding Claims, wherein at least one of the components of the appliance is spaced apart from the others so that the whole is not confined to a single housing.
9. A fluid treatment system and method according to Claim 8, wherein the reservoir is located separately from the physical conditioner and the purgeable filter.
10. A fluid treatment system according to any preceding Claim, wherein the reservoir is open to atmosphere.
11. A fluid treatment system according to any preceding Claim, wherein an electrical wire bridges the physical conditioner together with a substantial length of each of the upstream and downstream pipe-lines from the physical conditioner.
12. A fluid treatment system according to Claim 11, wherein the wire bridge is connected to a quality grounding to earth in the region of < 1 ohm.
13. A fluid treatment system according to any preceding Claim, comprising, an inlet pipe-line section having a non-return valve and a fluid flow sensor.
14. A fluid treatment system according to Claim 13, wherein the inlet pipe section merges with the feedback path.
15. A fluid treatment system according to any preceding Claim, wherein the purgeable filter comprises a back-flushing filter, in combination with timer and/or pressure differential sensor operated purge valve.
16. A fluid treatment system according to any preceding Claim, wherein the physical conditioner is downstream of the purgeable filter in the flow direction within the feedback path.
17. A fluid treatment system according to any preceding Claim, wherein the feedback path comprises, in the direction of flow, a riser pipe-line from within the reservoir, a non-return valve, a connection to the fluid inlet, an automatic air-vent, a pressure gauge, the purgeable filter, the physical conditioner, the pump and a return pipe into the interior of the reservoir.
18. A fluid treatment system according to any preceding Claim, wherein the feedback path comprises a riser pipe-line from within the reservoir forming an entry to the feedback path and a return pipe into the interior of the reservoir forming an exit from the feedback path, the termination of the return pipe being open and located so that the returning flow substantially follows an inner circumference of the reservoir to encourage creation of a vortex within the reservoir.
19. A fluid treatment system according to claim 18, wherein the riser pipe is located substantially at a vertical axis of the reservoir.
20. A method of reducing solutes in a fluid to be treated, the method comprising steps of filtering precipitated solutes and causing solutes to be precipitated in multiple passes through a feedback path which extends from and to a reservoir for the temporary storage of the fluid.
21. A method according to claim 20, wherein the reservoir provides temporary storage of partially treated fluid.
22. A method according to claim 20 or claim 21, wherein the fluid to be treated comprises water.
23. A fluid treatment substantially as hereinbefore described with reference to the accompanying drawing.
24. A method of reducing solutes in a fluid to be treated substantially as hereinbefore described with reference to the accompanying drawing.