WO2011032583A1

WO2011032583A1 - Water screening

Info

Publication number: WO2011032583A1
Application number: PCT/EP2009/061998
Authority: WO
Inventors: Ole GRØNBORG JENSEN; Jens SKJØLSTRUP
Original assignee: Skjølstrup & Grønborg Aps
Priority date: 2009-09-16
Filing date: 2009-09-16
Publication date: 2011-03-24

Abstract

A pool or spa water treatment plant (1 ) comprising a water inlet (10) adapted for receiving water from a pool or spa (100) and a water outlet (20) adapted for returning water to a pool or a spa (100) characterized in that a micro screen (30) is provided in-between said inlet (10) and said outlet (20) such that water flowing from said inlet (10) to said outlet (20) pass through said micro screen (30).

Description

Water screening

The present invention relates to treatment and maintenance of water contained in swimming pools and the like.

According to one aspect, the present invention relates to a pool water treatment plant. The plant comprise a water inlet adapted for receiving water from a pool and a water outlet adapted for returning water to the pool. The expression pool is, throughout this specification incl. claims, meant to denote any kind bathing facility incl. spas as well as private and public swimming and paddling pools.

The expression particle is, throughout this specification incl. claims, meant to denote any kind of particle incl. larger substances such as cell or flakes etc.

The expression screen is, throughout this specification incl. claims, meant to denote means for filtration, such as a filter element comprising a dew filter or equivalent configured for retaining impurities from a flow of liquid.

Background

In pool facilities, such as public and private swimming pools and the like, water is maintained by a combination of chlorination and filtration of circulated water.

Chlorine is generally used to kill bacteria and break down organic material in pool water, and the filtration serves to remove and retain debris and particles from a stream of water being lead from, and after filtration, to the pool. Chlorine may be consumed by the pool water at a relatively fast, but variable, rate depending on various factors such as the levels of bacteria and algae in the pool, the pool temperature, and the amount of sunlight shining on the water.

Chlorination of swimming pools, in terms of raw material cost, is relatively expensive. It is therefore, together with other drawbacks caused by chlorination, desirable to add no more chlorine than necessary, typically in the range of 0,3 - 3 ppm (parts per million), in order to maintain an acceptable water quality.

A by-product of chlorination of swimming pools and the like is that the chlorine over time reacts with various forms of contamination in the water, such as uric acid contained in the body sweat and urine of swimmers, to produce combined chlorine or chloramine which is the general term for several compounds containing chlorine and nitrogen.

Chloramine produces the chlorine smell of swimming pools, rather than chlorine per se, and it is the chloramine that causes swimmers eyes to itch as well as irritation of the swimmers skin.

Further, it has been found that chloramine can cause asthma, which is the reason why swimmers are more prone to asthma than athletes in other sports.

Generally, chloramine is opposed by increased chlorination of the water. An effective way of breaking down chloramine is to increase the chlorine level in the pool water to 5 or 6 ppm. However, for reasons of environmental issues as well as cost, this is preferably done only when required. Another by-product of chlorination of swimming pools is tri-halomethanes (THM). THM are chemical compounds, such as chloroform, which are formed when water is disinfected with chlorine, and in particular, THM occur when chlorine reacts with organic matter in water.

Therefore, as per the above, chloramines as well as THM will cause harmful and unpleasant conditions for swimmers as well as occupant within the pool areas, and further, chlorination potentially may cause serious disease, especially for children.

Generally seen, there is a strong desire in minimizing the required level of chlorination of pool facilities.

As already mentioned above, the pool water is, in addition to the chlorination, filtrated in order to retain and remove debris and particles from the water. In many, typically large, facilities, the filtration is performed by a sand filter, which generally is considered a very good filter for the purpose of filtrating pool water. As the retained debris and particles are accumulated in the sand, sand filters are, in order to be cleaned, typically back flushed at regular intervals. The intervals are ideally quite long, possibly as long as one or two weeks, as the back flush process requires a substantial volume of, typically heated, pool water, which of course is considered environmentally unfriendly as well as being otherwise costly.

It has been found that a part of the retained particles are skin particles, cells or flakes stemming from the pool guests. The skin particles, cells or flakes are retained by the sand, and over time; the skin particles, cells or flakes dis- solve whereby e.g. chloramine is released from the filter. Background art

Prior art does not address measurement, control or removal of human skin particles from pool water for the purpose of preventing decomposition of the particles into the water of the pool.

Examples of prior art pool treatment techniques are described in the following: FR 2721644 A teaches a self-cleaning swimming pool provided with at least one filter bed on the bottom of the pool to clean the lower layers of pool water as well as a collector for the filtered water which is situated between the filter bed and the bottom of the pool. The filter bed and the collector are, according to the document, linked to a return pipe. The filter bed material is sand and/or gravel and the collector consists of drain-pipes with perforations smaller than the filter bed particles. Additionally, the pool may be provided with an overflow unit which allows the water surface to be skimmed.

US 5833841 A teaches a method and apparatus for purifying pool water as well as and maintaining the purity of the pool water by initially leading the pool water into an ion exchanger in order to render the water acidic and hardness-free. Lime water consisting of a clear and saturated aqueous solution of white lime or white lime hydrate is thereafter added to provide a lime- carbonic acid equilibrium. At least some of the acidic and hardness-free wa- ter is re-circulated over a body of crushed limestone to establish a pH of not less than 7. According to the document, carbon dioxide and oxygen may also be added.

FR 291 1625 A teaches a device including a filtering pump for filtering pool water in accordance to the temperature of the water. A filtering pump is sug- gested started and stopped by a heating pump. A clock indicates water filtering, and two filtering time slots are established in different intervals.

WO 0235032 A teaches a filter pressure monitor for a swimming pool or spa filtration system comprising a pressure sensor in fluid communication with pressurized water from a filter pump. A pressure display and an audible alarm are further provided in order to signal a filter backwash requirement.

EP 2058282 A teaches monitoring and treatment of chlorinated swimming pool water in which chloramine may be present. The pool water is monitored and treated by: sensing the chlorine level of the water and, in dependence thereon, adding chlorine to the water; spectrophotometrically sensing a mixture of the water and a spectrophotometric reagent that is sensitive to chloramine and, in dependence thereon, modifying the addition of chlorine. In another aspect of the disclosed invention, the pool water is monitored and treated by: spectrophotometrically sensing a mixture of the water and a spectrophotometric reagent that is sensitive to copper or silver ions and, in dependence thereon, adding copper or silver ions to the water. Brief description of the invention

The present invention seeks to improve the general quality of pool water while lowering the impacts rendered to the environment by the present water treatment systems.

Up to this day, prior art has failed to teach a simple and yet reliable and inexpensive method of maintaining pool water incl. a pool water treatment plant adapted for realizing the method. According to one aspect of the invention, there is provided an improved pool water treatment plant as per the introductory part of this specification, and in particular upon configuring the pool water treatment plant such that that the plant further comprise a micro screen provided in-between the inlet and the outlet such that water flowing from the inlet to the outlet pass through the micro screen, a pool water treatment plant rendering the issues relating to de- composition or human skin particles in prior art filtration systems is provided.

Consequently, removing the above discussed human skin particles from the pool water before the particles are allowed to decompose, formation of chlo- ramine as well as THM are virtually eliminated.

According to one embodiment, the micro screen is configured for retaining particles having a size of minimum 10 microns, however depending on the size particles which is to be retained, alternative configurations of the micro screen may be applied such at a micro screen configured for retaining human skin particles having a size of at least 12, 15, 18, 20, 25, 30 or even 40 microns.

According to one embodiment, the water treatment may plant further comprises a sand filter.

According to one embodiment, the sand filter may be provided downstream of the micro screen.

According to embodiment, the micro screen may constitute a meshed filter element or a filtration panel having a cellular structure.

According to one embodiment, the treatment plant may be configured such that water flows through the micro screen by means of gravitation only.

According to one embodiment, the water treatment plant operates under atmospheric pressure. According to one embodiment, the micro screen may be arranged on a drum provided within a drum filter.

According to one embodiment, the micro screen may be arranged as panels provided within a disc filter.

According to one embodiment, the disc filter comprises juxtaposed or consecutive discs provided with a micro screen.

According to one embodiment, the micro screen may be arranged on a ro- tatable shaft having a centre of rotation.

According to one embodiment, at least a part of the micro screen may be arranged in a vat provided with means for monitoring water level in a space inter alia defined by the micro screen.

According to one embodiment, the water treatment plant may be provided with means for removing retained particles from the micro screen.

According to one embodiment, the water treatment plant may be provided with means for back flushing the micro screen with water.

According to one embodiment, the water used for back flushing the micro screen may constitute water being delivered through nozzles. The pressure of the pressurized water may be controlled such that virtually all particles and debris retained by the micro screen are washed or flushed away from the micro screen.

According to one embodiment, the water treatment plant may be provided with means for collecting the water used for back flushing the micro screen. According to one embodiment, the means for collecting the water constitute a collector arranged in a space inter alia defined by the micro screen. According to one embodiment, the water treatment plant further may be provided with means for leading the water used for back flushing the micro screen to a second outlet.

According to one embodiment, the water treatment plant further may be pro- vided with means configured for rotating the micro screen a predetermined angular step on basis of readings stemming from the means for monitoring the water level.

According to one embodiment, swimming pool comprising a water treatment plant according to the present invention is provided.

According to a second aspect of the present invention, a method of maintaining pool water is provided. The method inter alia comprises a step of controlling a concentration of human skin particles in the water.

According to one embodiment of the second aspect, the method further comprises the steps of:

- establishing a stream of water from the pool,

- passing the stream of water through a micro screen while retaining the human skin particles, and

- removing the particles from the filter at a predetermined interval,

According to one embodiment of second aspect, the interval may be determined such that the skin particles are removed from the micro screen before the particles dissolve. According to one embodiment of the second aspect, the method further comprises a step of, after the water pass through the micro screen, returning the water to the pool. According to one embodiment of the second aspect, the step of removing the particles from the micro screen comprises the steps of:

- back flushing the micro screen with pressurized flushing water,

- collecting the flushing water, and

- leading the flushing water away from the stream of pool water.

According to one embodiment of the second aspect, the particles constitute particles having a size in the range of 10 - 40 microns.

According to one embodiment of the second aspect, the human skin particles are removed from the micro screen at least three times weekly.

According to one embodiment of the second aspect, the human skin particles are removed from the micro screen at least at intervals of less than 48 hours. Brief description of the drawings

Figure 1 schematically illustrates a water treatment plant for a pool.

Figure 2 is a schematic diagram of a water treatment system for a pool.

Figure 3 is a schematic diagram of a water treatment system for a pool.

Detailed description with reference to the figures Figure 1 shows one embodiment of a pool treatment plant according to the present invention. The plant is in the illustrated embodiment provided with a cylindrical drum filter comprising a filter element constituting a micro screen 30 arranged on the peripheral face of the drum. The micro screen 30 may constitute a textile filtration fabric such as a cloth or canvas and the micro screen 30 may be provided or connected to the drum as a one piece element or as panels or similar.

The water treatment plant is adapted to, via the inlet 10, be in fluid communication with a pool outlet or a pool overflow whereby pool water is fed to the plant.

As can be seen in figure 1 , the inlet 10 supplies water to a space 31 defined inter alia by the micro screen 30.

Upon water flowing into the space 31 , the water, possibly by means of gravity only, seep through the micro screen 30 where particles having a size in excess of 10 microns are removed from the water. The through seeping water is collected or accumulated in a second space 32 from where the water, via the outlet 20, is, possibly by pumping means, lead either back to the pool or a equalisation tank in fluent communication with the pool, or to further treat- ment means such as means for further filtration 60 or additional treatment such as UV treatment and/or chemical treatment incl. monitoring or recordal of various parameters relating to the water quality etc.

Further as can be seen in figure 1 , upon water flowing into the space 31 inter alia defined by the micro screen 30, an internal level of water 39 will, due to flow restriction caused by the micro screen 30, will rise.

The level to which the water rise in the space 31 is determined by factors like the permeability of the micro screen 30, the flow rate of water being supplied to the treatment plant via the inlet 10 and the level of water accumulated in the peripheral space 33 (if any) of the water treatment plant. Over time, the permeability of the micro screen 30 will, as a result of retained particles and debris etc. fall whereby the level of water with in the space 31 , as per the above, rise.

As illustrated by numeral 38 in figure 1 , the water treatment plant may be provided with means or monitoring the level of water 39 present in the space 31 .

The means for monitoring 38 may be connected to not shown means for con- trolling rotation about an axis 50 of the drum accommodating the micro screen 30.

Upon the level of water 39 present in the space 31 rising to a predetermined level, the not shown means for controlling rotation of the drum may initiate rotation of the drum such that a fouled or partially clogged section of the micro screen 30 is rotated into a portion of the treatment plant provided with means for back flushing the micro screen 30.

The means for back flushing the micro screen 30 may constitute any suitable arrangement adapted to remove debris and particles from the micro screen 30. According to the embodiment illustrated in figure 1 , the arrangement for back flushing constitute, on an exterior side of the micro screen 30, an arrangement of nozzles 40 or equivalent connected to a pressurized supply of water, and on an interior side, within the space 31 , means for collecting the flushing water incl. retained particles and debris being sprayed onto and through the micro screen 30 by the nozzles.

The means for collecting the abovementioned flushing water may, as can be seen in figure 1 , constitute a drip tray 41 configured collecting a main part of the applied flushing water. The drip tray 41 may be connected to an outlet 45 in order to lead the collected flushing water incl. retained debris and particles away, possibly to drain or a sewer.

The not shown means for controlling and initiating rotation of the drum ac- commodating the micro screen 30 may be configured for stepwise rotation of the drum. Stepwise rotation of the drum allows the micro screen 30 to remain stationary until the level of water 39 present in the space 31 reaches a predetermined level. Upon a predetermined water level is reached, the drum rotates a predetermined angular step such that a part of the micro screen is conveyed to pass by the means for back flushing, and a part of a clean micro screen is convey into a position below the level of water 39, whereby the flow through the micro screen 30 is increased.

As an equal alternative, the not shown means for initiating rotation of the drum may be configured such that the drum rotates continuously which may be preferred if the water comprise a high level of contamination.

Obviously, stepwise rotation of the drum may, for environmental as well as economical reasons, be preferred as the consumed volume of flushing water may be limited significantly due to the back flushing possibly taking place only upon the drum being rotated.

It is of great importance to the functionality of the water treatment plant according to the present invention that:

- the intervals in-between rotations of the drum are controlled such that particles and debris retained by the micro screen 30 are removed from the water treatment plant before the particles or debris dissolve or disintegrate, and

- the pressure of the applied back flushing water are controlled such that the step of wash down, in an efficient manner, ensures that virtu- ally all the particles and debris retained by the micro screen 30 are washed or flushed away from the micro screen 30.

Further, it may be preferred to control the pressure of the applied back flush- ing water such that the applied flushing water do not mechanically damage or disintegrate the retained debris or particles.

Figures 2 & 3 are schematic flow diagrams of water treatment systems for a pool.

As can be seen, water may be lead from a pool's 100 overflow 105 via piping to the treatment plant 1 as already described above.

The water is, upon removal of debris and particles in excess of 10 microns, lead from the outlet 20 back to the pool 100, possibly via an additional filter 60 (Figure 3) such as a sand filer, or to a equalisation tank 90 typically found in connection pool water treatment plant serving one or more a pools of the type incorporating peripheral overflow. The drawings accompanying the present specification serves the purpose of illustration only.

For reasons relating of clarity, several features and components which may or may not be considered to represent common knowledge, are intentionally left out of the above teachings. One example hereupon is left out teachings relating to sealing or overflows etc.

Claims

C l a i m s

1 . A pool water treatment plant (1 ) comprising a water inlet (10) adapted for receiving water from a pool (100) and a water outlet (20) adapted for returning said water to a pool (100) characterized in that a micro screen (30) is provided in-between said inlet (10) and said outlet (20) such that water flowing from said inlet (10) to said outlet (20) pass through said micro screen (30).

2. A pool water treatment plant according to claim 1 , wherein said micro screen (30) is configured for retaining particles having a size of minimum 10 microns.

3. A pool water treatment plant according to claim 1 or 2, wherein said water treatment plant further comprises a sand filter.

4. A pool water treatment plant according to claim 3, wherein said sand filter is provided downstream of said micro screen.

5. A pool water treatment plant according to any of the preceding claims, wherein said micro screen (30) constitute a meshed filter element or a filtration panel having a cellular structure.

6. A pool water treatment plant according to any of the preceding claims, wherein said treatment plant is configured such that said water flows through said micro screen (30) by means of gravitation only.

7. A pool water treatment plant according to any of the preceding claims, wherein said water treatment plant operates under atmospheric pressure.

8. A pool water treatment plant according to any of the preceding claims, wherein said micro screen (30) is arranged on a drum provided within a drum filter.

9. A pool water treatment plant according to any of the preceding claims 1 -7, wherein said micro screen (30) is arranged as panels provided within a disc filter.

10. A pool water treatment plant according to claim 9, wherein said disc filter comprises juxtaposed or consecutive discs provided with said micro screen.

1 1 . A pool water treatment plant according to any of the preceding claims, wherein said micro screen (30) is arranged on a rotatable shaft having a centre of rotation (50).

12. A pool water treatment plant according to any of the preceding claims, wherein at least a part of said micro screen (30) is arranged in a vat (35) provided with means (38) for monitoring water level (39) in a space (31 ) inter alia defined by said micro screen (30).

13. A pool water treatment plant according to any of the preceding claims, including means for removing retained particles from said micro screen (30).

14. A pool water treatment plant according to any of the preceding claims, including means for back flushing (40) said micro screen (30) with water.

15. A pool water treatment plant according to claim 14, wherein said water used for back flushing said micro screen (30) constitute water being delivered through nozzles, and where the pressure of said pressurized water is con- trolled such that virtually all particles and debris retained by said micro screen (30) are washed or flushed away from said micro screen 30.

16. A pool water treatment plant according to claim 14 or 15, wherein said water treatment plant is provided with means (41 ) for collecting said water used for back flushing said micro screen (30).

17. A pool water treatment plant according to claim 16, wherein said means for collecting said water constitute a collector arranged in a space (31 ) inter alia defined by said micro screen (30).

18. A pool water treatment plant according to claim 17, wherein said water treatment plant further is provided with means for leading said water used for back flushing said micro screen to a second outlet (45).

19. A pool water treatment plant according to any of the claims 12 - 18, wherein said water treatment plant further is provided with means configured for rotating said micro screen (30) a predetermined angular step on basis of readings stemming from said means for monitoring (38) said water level (39).

20. A swimming pool comprising a water treatment plant according to any of the preceding claims.

21 . A method of maintaining pool water inter alia comprising a step of controlling a concentration of particles in said water characterized in that said particles constitute human skin particles.

22. A method of maintaining pool water according to claim 21 , wherein said method further comprises the steps of:

- establishing a stream of water from said pool,

- passing said stream of water through a micro screen while retaining said human skin particles, and

- removing said particles from said filter at a predetermined interval,

23. A method of maintaining pool water according to claim 22, wherein said interval is determined such that said skin particles are removed from said micro screen before said particles dissolve.

24. A method of maintaining pool water according to claim 22 or 23, wherein said method further comprises a step of, after said water pass through said micro screen, returning said water to said pool.

25. A method of maintaining pool water according to any of the claims 22 -

24, wherein said step of removing said particles from said micro screen comprises the steps of:

- back flushing said micro screen with pressurized flushing water,

- collecting said flushing water, and

- leading said flushing water away from said stream of pool water.

26. A method of maintaining pool water according to any of the claims 21 -

25, wherein said particles constitute particles having a size in the range of 10-40 microns.

27. A method of maintaining pool water according to any of the claims 22 -

26, wherein said human skin particles are removed from said micro screen at least three times weekly.

28. A method of maintaining pool water according to any of the claims 22 -

27, wherein said human skin particles are removed from said micro screen at least at intervals of less than 48 hours.