GB2363117A

GB2363117A - Water treatment apparatus

Info

Publication number: GB2363117A
Application number: GB0107845A
Authority: GB
Inventors: Timothy Maurice Shakesby
Original assignee: Shakesby & Sons Ltd
Current assignee: Shakesby & Sons Ltd
Priority date: 2000-05-19
Filing date: 2001-03-29
Publication date: 2001-12-12
Also published as: GB0107845D0; GB0011989D0

Abstract

Water treatment apparatus comprises a water inlet and output manifold (14, 32, see Figs. 1, 2) for receiving input water to be treated and outputting treated water, a pressure vessel (10, 24, see Figs. 1, 2) containing particulate material for treating the input water, a delivery and collection tube inside the vessel (12, 26, see Figs 1,2) for conveying water through the apparatus. The tube is coupled at one end to the manifold and at the other end 46 to the inside of the vessel via a tubelet coupling. The tubelet coupling includes a plurality of water-conveying, flexible tubelets 38, 40 each connected at a first end to the second end 46 of the tube and being closed at their second ends with a number of perforations 42, 44 along their length. The flexible tube/tubelet arrangement can easily be introduced through the restrictive opening of the pressure vessel. The perforations reduce or remove the need for graded gravel or an underbed in the container. The particulate material is typically ion exchange material.

Description

2363117 C879/S Title: I=rovements in and relating to water softeners

5 Field of inventio

This invention concerns water treating apparatus such as water softeners. In particular, the invention concerns an improved collecting and distribution device as is located at the base of a reservoir containing water softening media, typically ion exchange media, through 10 which water is passed during a water treatment process involving the removal of unwanted ions from the water by ion exchange, and generally referred to as water softening.

Background to the inventio

15 A conventional brine-based water softener typically comprises a pressure vessel typically formed from glass fibre reinforced plastics or a homogenous plastics material or metal to which hard water is supplied under mains supply pressure, and from which softened water is retrieved after it has passed through the softening media contained in the vessel.

20 Typically the softener includes a central upper manifold which communicates with a downwardly extending central tube, the lower end of which is positioned just above the inside base of the vessel, and incoming hard water enters the vessel through an annular array of ports in the manifold, radially spaced from the central tube. After descending through the softening media, to the base of the vessel, the treated water passes up to the 25 manifold via the central tube, for connection to a pipe leading to one of more draw-off points, or a storage tank.

After a given volume of water has been processed, the softening media will normally need to be regenerated by flushing the media typically with a brine solution. Valves are 30 provided to direct the flow accordingly, and transfer the brine to a drain after it has passed through the media in the vessel.

It is known to introduce into the vessel a layer of particulate material such as graded gravel or sand, to occupy the lower region of the vessel around the lower open end of the central tube and to increase the effective collection area attributable to the tube during the softening process, and during back flushing, to cause the reverse flow of flushing medium 5 such as water and/or brine to spread out radially before it ascends through the softening media during the back washing and regeneration process.

In order to prevent sand or other particulate material from passing into the tube it is known to fit over or combine with the lower end of the tube a filter or strainer, to allow liquid to 10 pass into and out of the tube but to prevent the ingress of sand or other particulate material. Sometimes the filter or strainer is such that particulate matter could pass, but this can be prevented by surrounding the tube by a graded support bed (more often a graded gravel bed), in which larger particles are located around the tube, too are to pass, and which separate the tube and filter/strainer from smaller particles in the bed. Where 15 the support bed is of a single grade of media, it is sometimes known as an underbed.

This arrangement works adequately for relatively tall, relatively small diameter vessels, but there is a demand for reduced height vessels to permit them to be located below kitchen worksurfaces and the like. The volume of the vessel dictates the volume of 20 softening media which is available for water treatment, and the flow rate and volume of water which can be treated between regenerations. If the vessel height is restricted, its cross-section (typically its diameter since the vessel will normally be circular in crosssection), must be increased proportionately, to maintain a constant vessel volume. A given depth of sand or other particular material is required in the base of the vessel to achieve 25 the spreading action desired, and with a large diameter vessel the volume of sand in the base of the vessel increases quite disproportionately, thereby reducing the efficiency of the unit.

It is an object of the present invention to remove or reduce the need for the support/graded 30 gravel or underbed in a water treatment vessel such as a water softener through which hard water is passed to reduce the dissolved hardness content.

SummaEy of the inventio 5 According to the present invention, there is provided a water treatment apparatus comprising:

(a) a water inlet and output manifold for receiving input water to be treated in the apparatus and for outputting treated output water from the apparatus; (b) a pressure vessel connected to the manifold, the vessel including water treating means 10 for treating the input water to provide the output water; (c) a delivery and collection tube for conveying water through at least part of the apparatus, the tube being included within the vessel, the tube being fluidly coupled at its first end to the manifold and fluidly coupled at its second end via coupling means to the treating means, 15 the coupling means comprising a plurality of water conveying flexible tubelets, each tubelet:

(d) being connected at a first end thereof to the second end of the tube; (e) being closed at a second end thereof; and (f) including a plurality of perforations at spaced-apart regions along its length through 20 which water can flow.

The invention provides the advantage that the coupling means is capable of removing or reducing the need for the support/graded gravel or underbed in water treatment vessels of conventional water treatment apparatus such as water softeners through which hard water 25 is passed to reduce the dissolved hardness content.

Preferably, the tubelets are generally radially laterally extending and sufficiently flexible to enable them to be bent downwardly or upwardly to occupy a smaller area to allow the second end of the tube to be fitted into or removed from the pressure vessel through a 30 restricted opening of the vessel. Such flexibility enables the coupling means to be installed through a smaller opening than would possible if the tubelets were substantially rigid.

Smaller openings are more convenient in water bearing apparatus because standard fixtures such a screw-threaded connectors can be employed.

In order to render that apparatus durable in use, it is preferable that each tubelet is 5 corrugated to render it highly flexible but generally resistant to crushing. Such corrugation makes the tubelets more robust, thereby improving reliability.

Conveniently, the tube is mounted substantially centrally within the vessel. Such central mounting simplifies the design of the apparatus and potentially renders the apparatus easier 10 to manufacture.

In order to reduce the cost of manufacture, each tubelet is formed from plastics material. Use of plastics enables the tubelets with their fine perforations to be quickly and cheaply mass-produced.

The inventor has found that it is preferable for the tubelets to comprise low density polyethylene. Alternatively, the tubelets; can comprise polypropylene. Both polyethylene and polypropylene are flexible durable plastics materials which are well adapted to being submerged over long periods in water without suffering severe degradation or corrosion.

Likewise, the tube preferably comprises medium density polyethylene. Alternatively, the tube can beneficially comprises polypropylene.

The inventor has appreciated that rapid assembly of the apparatus and ease of serviceability 25 are significant attributes of the apparatus. Thus, the tube preferably includes at its second end a plurality of threaded openings for receiving by screw fitting first ends of the tubelets. Alternatively, the tube includes at its second end a plurality of openings having annular ribs for co-operating with corrugations of the tubelets, the interaction between the ribs and the corrugations serving to retain the first ends of the tubelets in place during normal 30 operation of the apparatus.

In one embopdiment of the invention, it is desirable that the restricted opening is a 2 1/2 NPSM threaded circular opening and the manifold is adapted by means of an externally threaded tubular protrusion to be screwed into the 2 1/2 " NPSM opening. Such opening diameters are convenient to employ in the apparatus and result in an easily installable 5 product. More preferably, the tubelets are radially collapsable so as to form a bundle or cluster which be pushed through the 2 1/2" NPSM opening.

In one embodiment, the tube is beneficially fabricated from medium density polyethylene and has an external diameter of the order of 50 mm and the tubelets are formed from low 10 density polyethylene and have an external diameter of the order of 27 min and an internal diameter of the order of 23 mm.

The aforementioned 21/2" NPSM internally threaded circular opening usually referred to as 64 a 21/2" opening" has a corresponding metric dimension of the order of 69mm.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a diagrammatic cross-section through a tall narrow pressure vessel including 20 a central internal tube and a layer of sand in a base region of the vessel; Figure 2 is a diagrammatic cross-section through a low-profile larger- diameter pressure vessel including an internal central tube and a layer of sand in a base region of the vessel; Figure 3 illustrates, in a perspective view, a lower end of the central internal tube of Figure 2 modified in accordance with the invention to comprise flexible lateral tubes; and Figure 4 is a diagrammatic view of the lower end of the tube shown in Figure 3, the flexible tubes being collapsed into a cluster to allow the flexible tubes to pass through a circular opening in the upper end of the vessel of Figure 2.

In Figure 1, a tall narrow vessel 10 has a central internal tube 12 which extends from a manifold 14 which is sealingly secured into a threaded opening in a flange 16 at the upper end of the vessel 10. A lower end of the tube 12 is capped with a perforated wall closure 5 18, which is buried in a layer of sand 20. An annular space 22 around the tube 12 is filled with larger particulate material through which water passes after being introduced into the vessel 10 (typically through apertures (not shown) in the manifold around the central tube 12), from a water supply having a positive head of pressure. The larger particulate material serves to substitute sodium for any dissolved hardness in the water. After passing 10 through the sand layer 20, the now softened water enters the central tube 12 via the perforations in the wall of the closure 18, and after ascending through the pipe 12, the now softened water can be conveyed through porting (not shown) in the manifold 14, for delivery to a tap or water storage unit.

15 Figure 2 shows the more preferred design of vessel for fitting below kitchen worksurfaces, where headroom is insufficient to accommodate vessels of the earlier taller narrow design of Figure 1. Here the vessel is denoted by reference numeral 24, the central tube by 26, the lower closure by 28, and the upper flange by 30. A manifold is denoted by reference numeral 32. The sand layer 34 has to be of greater depth than in Figure 1, and now 20 extends over the larger cross-section of the vessel 24, and because the latter is of reduced height, the volume occupied by the sand relative to the remaining volume 36 available for the water softening medium, is greater than is the case in Figure 1. The unit of figure 2 is therefore less efficient than that of Figure 1 in this context.

25 In accordance with the invention, the sand layer can if desired, be dispensed with, so increasing the volume 36 of the Figure 2 available foi the softening medium, by closing the lower end of the tube 26 and providing a plurality of smaller diameter laterally extending feeder/distributor tubelets such as 38, 40, as shown in Figure 3. The outer end of each of these small diameter tubelets 38, 40 is closed, and the interior communicates 30 centrally with the interior of the central tube 26. The walls of each of the small diameter tubelets are corrugated and are perforated as at 42 and 44 in Figure 3a. The perforations are located at spaced-apart regions along the length of each of the smaller diameter tubelets, and circularly around the corrugations in the wall of each tubelet. The perforations allow the passage of water therethrough, and by forming the small diameter tubelets from resilient plastics material which imparts a degree of flexibility to each of the tubelets such as 38 and 40, each of these laterally extending tubelets can be bent upwardly 5 or downwardly. If all of the tubelets; are thus bent so as to form a cluster, the bounding diameter of the cluster will be much smaller than the bounding diameter of the assembly when unconstrained and extending generally laterally from the central tube 26. The formation of such a cluster by manually collectively bending all of the laterally extending tubelets in the same direction, is shown diagrammatically in Figure 4.

By bending the tubelets to form such a cluster, the area occupied by them is now sufficiently small for the cluster to be pushed through a relatively small opening such as a 21/2" opening in the upper end of a vessel such as 24.

15 Since the tube 26 will normally be formed with an externally threaded lower end onto which the perforated wall closure 28 is screwed, the most convenient way of closing off the end of the tube 26 and providing a mounting for the lateral tubelets such as 38 and 40 is to provide an internally threaded cylindrical cup 40 which is adapted to be screwthreadedly engaged onto the lower end of the tube 26 in place of the closure 28. The cup 20 46 is in fact shown in Figure 3, and it will be understood that the lower end of the cup is closed so that fluid entering the cup from the tube 26 can only exit via the perforations such as 42, 44 in the laterally extending small diameter tubelets 38, 40. Fluid flow in the opposite direction via the perforations in the walls of the small diameter tubelets will be collected in the cup 46 and under continued head of pressure, the liquid will be forced up 25 through the inside of the tube 26 as previously described.

C879/S

Claims

1. A water treatment apparatus comprising:

(a) a water inlet and output manifold for receiving input water to be treated in the apparatus and for outputting treated output water from the apparatus; (b) a pressure vessel connected to the manifold, the vessel including water treating means for treating the input water to provide the output water; (c) a delivery and collection tube for conveying water through at least part of the apparatus, the tube being included within the vessel, the tube being fluidly coupled at its first end to the manifold and fluidly coupled at its second end via coupling means to the treating means, the coupling means comprising a plurality of water conveying flexible tubelets, each tubelet:

(d) being connected at a first end thereof to the second end of the tube; (e) being closed at a second end thereof, and (f) including a plurality of perforations at spaced-apart regions along its length through which water can flow.

2. An apparatus according to Claim I wherein the tubelets are generally radially laterally extending and sufficiently flexible to enable them to be bent downwardly or upwardly to occupy a smaller area to allow the second end of the tube to be fitted into or removed from the pressure vessel through a restricted opening of the vessel.

3. An apparatus according to Claim I or 2 wherein each tubelet is corrugated to render it highly flexible but generally resistant to crushing.

4. An apparatus according to any preceding claim wherein the tube is mounted substantially centrally within the vessel.

5. An apparatus according to Claim 1, 2, 3 or 4 wherein each tubelet is formed from plastics material.

6. An apparatus according to Claim 5 wherein the tubelets comprise low density polyethylene.

7. An apparatus according to Claim 5 wherein the tubelets comprise polypropylene.

8. An apparatus according to any preceding claim wherein the tube comprises medium density polyethylene.

9. An apparatus according to any one of Claims I to 7 wherein the tube comprises polypropylene.

10. An apparatus according to any preceding claim wherein the tube includes at its second end a plurality of threaded openings for receiving by screw fitting first ends of the tubelets.

11. An apparatus according to any one of Claims 1 to 9 wherein the tube includes at its second end a plurality of openings having annular ribs for co-operating with corrugations of the tubelets, the interaction between the ribs and the corrugations serving to retain the first ends of the tubelets in place during normal operation of the apparatus.

12. An apparatus according to Claim 2 wherein the restricted opening is a 2 1/2" NPSM threaded circular opening and the manifold is adapted by means of an externally threaded tubular protrusion to be screwed into the 2 1/2" NPSM opening.

13. An apparatus according to Claim 12 wherein the tubelets are radially collapsable so as to form a bundle or cluster which can be pushed through the 2 1/2" NPSM opening.

t

14. An apparatus according to any one of Claims I to 5 wherein the tube is fabricated from medium density polyethylene and has an external diameter of the order of 50 mm and the tubelets are formed from low density polyethylene and have an external diameter of the order of 27 mm and an internal diameter of the order of 23 mm.

15. An apparatus substantially as herein before described with reference to one or more of Figures 1 to 4.