This invention relates to a device for water treatment, as well as to a method for the regeneration of a device for water treatment.

More particularly, it relates to a device of the type whereby the water during treatment is brought into contact with a treatment medium, whereby this treatment medium is regenerated regularly by having a regeneration agent flow through the treatment medium, and whereby the device is provided with a flow rate regulator in order to regulate the flow rate of the regeneration agent during regeneration.

In the first place, the invention is intended for devices which serve for the purpose of water softening, whereby the water to be treated is fed through an ion exchange resin, in such a manner that the calcium and magnesium salts are replaced by sodium salts, and whereby the ion exchange resin is regenerated regularly by means of brine. More generally, however, the invention may also be used in other applications for water treatment, whereby another treatment medium and/or other regeneration agent is applied.

It is important that in such devices, the flow rate of the regeneration agent, at the moment when it is fed through the treatment medium, is limited to a certain value, in such a manner that the regeneration agent gets sufficient time for performing the regeneration. It is also desirable that this flowing takes place with a rather constant average flow rate, as a better efficiency

in regeneration is obtained with a uniform flow of the regeneration agent.

In order to obtain such a relatively uniform flow which is more or less limited to a certain flow rate, it is known to equip the aforementioned devices with a flow rate regulator.

A device of the aforementioned type which is equipped with such flow rate regulator is known, amongst others, from the international patent application WO 98/04349.

The invention aims at an improved device for water treatment, more particularly a device whereby the flow rate regulator applied therewith is improved.

More particularly, it aims at a device having a flow rate regulator which does not only function well, but whereby the constructive design thereof is particularly simple and whereby such flow rate regulator consequently can be realized at a low cost price.

To this aim, the invention in the first place relates to a device for water treatment of the aforementioned type, with the characteristic that the flow rate regulator shows a passage, as well as an element which is elastically bendable under the influence of the pressure exerted thereupon by the flow, which element, by its deflection, closes off the aforementioned passage to a minor or major extent. By using such elastic element, the flow rate can be regulated and/or limited in a simple manner.

Preferably, the device is characterized in that the flow rate regulator has a flow channel with an entry and an exit, and that the elastically bendable element is

designed in the form of an obstruction which is provided in the flow channel, in such a manner that under the influence of the flow, a pressure difference is created over the elastically bendable element and that it is deflected in function of this pressure difference.

In a particular form of embodiment, according to the invention the passage and the elastically bendable element are designed in such a manner that, at least at a certain pressure difference over the elastically bendable element, an oscillation effect is obtained, whereby a pulsating effect is created in the flow of liquid. As a result thereof, the regeneration agent flows through the treatment medium with a repeating shock effect. It turned out that as a result thereof, a better efficiency of the regeneration was obtained. Preferably, the oscillation is such that, globally seen, the uniform flow is not disturbed. To this aim, it is preferred that the oscilla- tion has a frequency of at least 10 Hz.

It is noted that this oscillation effect according to the invention not necessarily has to be realized by means of the flow rate regulator described heretofore and that the invention also extends to devices for water treatment, as well as methods for regenerating the treatment medium, whereby the aforementioned oscillation effect is created in any other manner.

It is also noted that the invention also relates to flow rate regulators which, as mentioned before, use an elastically bendable element which cooperates with a passage, regardless whether these flow rate regulators are intended for being applied in a device for water treatment or not.

With the intention of better showing the characteristics

according to the invention, hereafter, as an example without any limitative character, a preferred form of embodiment is described, with reference to the accompany- ing drawings, wherein : figure 1 schematically represents a device according to the invention ; figure 2 in cross-section represents a practical form of embodiment of the flow rate regulator which is indicated by arrow F2 in figure 1 ; figure 3 represents a cross-section according to line III-III in figure 2 ; figure 4 represents a view similar to that of figure 2, but for another condition.

As represented in figure 1, the invention relates to a device 1 for water treatment, whereby the water during treatment is brought into contact with a treatment medium 2, whereby this treatment medium 2 is regenerated regu- larly by having a regeneration agent 3 flow through the treatment medium 2, and whereby the device 1 is provided with a flow rate regulator 4 for regulating the flow rate of the regeneration agent 3 during regeneration.

As known, and as represented schematically, hereby a treatment agent 2 can be used which is immobilized in a tank 5 around a central conduit 6. The water to be treated is directed through the device 1 in a manner as indicated in dash-dot line 7. During regeneration, as indicated schematically in dashed line 8, the regenera- tion agent 3 is directed through the treatment medium 2, preferably in reverse flow.

The regeneration agent 3 is supplied from, for example, a tank 9.

Normally, the regeneration is controlled automatically by means of a regulator 10 which is provided with the necessary valves. In consideration of the fact that, on one hand, the control of the device 1, as well as the construction of such regulator 10, is sufficiently known from the state of the art, amongst others, from the aforementioned international patent application WO/04349, and, on the other hand, the invention relates to the regulation of the flow rate, the control by means of the regulator 10 will not be discussed in further detail.

As aforementioned, the invention in the first place is intended for water softeners. In such case, the treatment medium 2, for example, consists of an ion exchange resin, the regeneration agent 3 of brine, and the tank 9 of a brine barrel which may form part of a brining device.

The particularity of the invention consists in that the device 1 comprises a flow rate regulator 4 which, as illustrated in figures 2 to 4, substantially consists of a flow channel 11 with an entry 12 and an exit 13, whereby in this flow channel 11, a passage 14 is formed and an elastically bendable element 15 is applied which, under the influence of the pressure exerted thereupon by the flow, can be deflected and thereby closes off the passage 14 to a minor or major degree and thereby regulates the flow.

The elastically bendable element 15 consists of an element which is applied upstream from the aforementioned passage 14 and which is supported freely at its edges in such a manner that it can be bend in the direction of the passage 14 by the pressure exerted thereupon, such that this passage 14 is further closed off with increasing pressure, as the elastically bendable element 15 gets situated closer against this passage 14.

The element 15 itself consists of an elastic material, such as EPDM or silicones, in such a manner that the aforementioned elastic deflection is obtained by the elasticity of the element 15 itself.

The element 15 is also designed as an elastic shield extending through the flow channel 11 of the flow rate regulator 4, more particularly in the form of an elastic disk, whereby an open connection, of a considerably smaller diameter, passage, respectively, than the flow channel 11, consists between the parts of the flow channel 11 which are situated on the respective opposite sides of the aforementioned element 15.

In the represented example, the open connection consists of one opening 16 in the element 15, but principally, this may also be several openings. According to a not- represented variant, the open connection can also be formed by one or more passages which are not applied in the element 15 itself, but, for example, in the housing 17, for example, in the form of grooves along the circumference of the element 15.

The passage 14 also shows a considerably smaller passage, diameter, respectively, than the flow channel 11, but preferably a larger passge than the opening 16. This passage 14 is situated centrally in respect to the elastically bendable disk.

It is obvious that, according to a not-represented variant, the passage 14 in itself may also be formed by several separate openings, although, in respect to the closing-off effect, one opening is preferred.

As represented, the passage 14 and the opening 16 are situated such that they are shifted in respect to each

other, in such a manner that, by the deflection of the element 15, a complete closing-off of the passage 14 is obtained.

Preferably, the whole is of a simple construction, in that the element 15, as aforementioned and as represented in the figures, consists of a simple round disk. The construction of the housing 17 may also be simple by composing the latter, as represented, of two parts 18 and 19 which can be screwed together and consist, for example, of plastics, whereby in between these parts, a seat for the element 15 is formed.

In the represented example, the flow rate regulator 4 is also equipped with a filter 20 which is provided upstream from the element 15 and which preferably has perforations which are smaller than the diameter of the opening 16.

The flow rate regulator 4 can be mounted in the device 1 in different manners. According to figure 1, it is mounted in the draw-off conduit 21, between the tank 9 and the regulator 10. According to a variant, it may also be integrated in the regulator 10.

The flow rate regulator 4 does not necessarily have to be provided directly in the flow of regeneration agent 3.

Preferably, even, the regeneration agent 3 shall be drawn off by means of a water jet pump, or a so-called ejector, and the flow rate regulator 4 is placed in the supply line of the water jet pump in order to provide in this manner indirectly for the regulation of the flow rate.

Practice has shown that in this manner, a very accurate regulation is obtained.

The functioning can simply be deduced from the figures.

When a flow of liquid flows through the flow channel, a

pressure difference over the element 15 is created due to the small passage of the opening 16, as a result of which this element 15, as illustrated in figure 4, is deflec- ted. From a given moment, the element 15 is lying so closely to the passage 14 that the flow to the passage 14 is reduced and the flowing is limited with a further increase of the flow rate.

As a result of a right choice of material for the element 15 and a right positioning of the element 15 in respect to the passage 14, it can also be obtained that an oscillation effect is achieved at a certain pressure difference over the element 14. As a result of the pressure difference, the element 15 hereby is pushed up to the edge 22 of the passage 14, whereby this latter is closed off completely. As after closing-off the passage 14, a higher pressure can build up again at the underside of the element 15, this latter comes back up again.

Subsequently, a flow is created again, with the result that the element 15 again is deflected and closes off the passage 14. This phenomenon is repeated continuously which, of course, results in an oscillation effect.

The functioning of the flow rate regulator 4, thus, can be based, depending on the construction of the latter and on the flow rate, on two principles, namely the partial closing-off of the passage 14 and/or the pulsating closing-off of the passage 14.

The flow rate regulator 4 provides for that a rather constant flow rate is obtained.

The aforementioned oscillation effect does not only have the advantage that a regulation of the flow rate is obtained, but that, as mentioned in the introduction, a better efficiency of the regeneration is achieved. In

order not to disturb the uniformity of the flow through the treatment medium 2, it is preferred that the vibra- tion takes place sufficiently fast and has a frequency of at least 10 Hz.

As already mentioned in the introduction, the invention also relates to flow rate regulators having the construc- tion described heretofore, regardless whether those are intended for application in a water softening device or such.

It is obvious that such flow rate regulators can also show their usefulness in other applications, whereby a relatively simple and reliable regulation of the flow rate, of water or of another liquid, has to be provided.

So, for example, it is not excluded to apply the afore- mentioned flow rate regulator in a reverse-osmotic- membrane filtration in order to guarantee for an almost constant flow rate. Also embodiments which are designed in such a manner that they function in a pulsating manner, are also useful in a reverse-osmotic-membrane filtration, as it is obtained, due to the pulsations, that the stagnant laminate-like layer of dirt and/or salts which is formed at the membrane, is broken and is discharged, as a result of which the reduction of the efficiency as a result of the presence of such layer is excluded.

The present invention is in no way limited to the forms of embodiment described by way of example and represented in the drawings, on the contrary may such device, method and flow rate regulator be realized according to diffe- rent variants without leaving the scope of the invention.