Filtering device for filtering water and liquids in general

DESCRIPTION

Technical scope

The present invention relates to a filtering device for filtering water and liquids in general including the features set out in the preamble of the main claim.

State of the art

Such devices are known and widespread in the marketplace owing to their capacity to provide, at a domestic level, drinking water which has improved characteristics, both chemical characteristics (salinity, hardness, etc.) and organoleptic characteristics in comparison with tapwater. A typical example of such devices is described in WO9613318 from the same applicant. The filtering device set out therein is of the type involving a jug with filtration by gravity, wherein the water introduced into the upper reservoir passes slowly into the lower reservoir, running through a filter cartridge which contains filtering elements with activated carbon and ion exchange.

The filtering efficacy of the cartridge depends on various factors, among which the contact time between the filtering means and the water to be filtered has obvious importance. The passage of the water into the cartridge is brought about by gravity and therefore the flow, understood as flow rate over a unit of time, varies in accordance with the pressure differential upstream and downstream of the cartridge, which in turn depends both on the water level in the upper reservoir for collecting the water to be filtered and on the level of filtered water in the lower reservoir.

Consequently, the filtered water has variable characteristics during the filtering phase. There is known on the market a filtering jug, wherein the conduit which receives the filter cartridge is closed at the bottom and has a discharge opening for the filtered water that is positioned in the vicinity of the upper reservoir. In that manner, the influence of the degree of filling of the lower reservoir on the flow of filtered water is substantially cancelled out.

However, this solution involves some obvious disadvantages. A first disadvantage consists in that, although the gradual filling of the lower reservoir does not influence the flow rate at the discharge opening for the filtered water, that flow rate is nevertheless irregular and non-constant with respect to the varying level in the upper reservoir. Furthermore, the conduit for receiving the cartridge is not accessible from below in order to facilitate the removal of the used cartridge during replacement thereof. Therefore, it is necessary to provide geometries and forms for the cartridge portion protruding into the upper reservoir which allow it to be gripped and removed, which, in addition to determining the overall geometry of the cartridge, influences its dimensions and interchangeability with cartridges from other manufacturers. Another disadvantage consists in the difficulty of cleaning the seat for receiving the cartridge during maintenance of the filtering device. Since the conduit is closed at the bottom, it is similarly inaccessible. Another disadvantage concerns the possibility of regulating the filtering flow. That may be required, for example, in order to adapt the flow in accordance with the hardness parameters or the organoleptic conditions of

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the water to be filtered. For example, during summer-time the water may smell strongly of chlorine, the neutralisation of which can require greater filtering times than those necessary during winter-time. Description of the invention The technical problem addressed by the present invention is to provide a filtering device for filtering water and liquids in general, which device is structurally and functionally adapted to overcome the disadvantages set out with reference to the prior art cited.

This problem is solved by the invention with a filtering device for filtering water and liquids in general, which device is constructed in accordance with the appended claims. Brief description of the drawings

The features and advantages of the invention will be better understood from the following detailed description of some of the preferred non-limiting embodiments thereof illustrated, merely by way of non-limiting example, with reference to the appended drawings, in which:

Figure 1 is a longitudinal section of a filtering device according to a first embodiment of this invention, which device is integrated in a jug;

Figure 2 is a partially exploded view of the jug of Figure 1; - Figure 3 is a perspective top view of a detail of the jug of Figure 1;

Figures 4 and 5 are a cross-section and a longitudinal section of the detail of Figure 3, respectively;

Figures Sa and 5b are views, drawn to an enlarged scale, of respective construction variants of the jug of Figure 1; - Figure 6 is a partially exploded longitudinal section of a filtering

device according to a second embodiment of this invention, which device is integrated in a jug;

Figures 7 and 8 are a side view and a front view, drawn to an enlarged scale, of a detail of the jug of Figure 6, respectively; - Figures 9 and 10 are views similar to Figures 7 and 8 of a construction variant of the detail represented therein;

Figure 11 is a perspective view, drawn to an enlarged scale, of another variant of the detail of Figure 7;

Figure 12 is a schematic view, drawn to an enlarged scale, of a construction variant of the device according to the invention.

Preferred embodiments of the invention

In the Figures, a filtering device according to a first embodiment of the invention is generally designated 1. The filtering device 1 is of jug-like form, but similarly the invention could be adapted to devices for preparing infusions, such as tea, coffee and the like. The device 1 comprises a receptacle 2 which is provided with a handle 3 and which is closed, in the upper portion, by a lid 4. The lid is in turn provided with a spring biased flap 5 which automatically closes in an openable manner a pouring spout 6 during pouring. A container 7 is fitted to the interior of the receptacle 2 and secured to the mouth thereof, so as to define a first reservoir 8 for collecting the water to be filtered, in the bottom 9 of which a discharge conduit 10 is open. A filter cartridge 11 is removably arranged in the conduit 10. The remainder of the receptacle 2 defines a second reservoir 12 for collecting the filtered water. The positioning of the above-described elements is such that the water

introduced into the first reservoir 8 flows by means of gravity into the second reservoir 12, passing by way of the conduit 10 through the filtering material which is contained in the filter cartridge 11. All the above-mentioned details are present in each of the embodiments of the present invention and are therefore indicated by the same reference numerals.

With specific reference to the embodiment of Figures 1 and 2, the conduit 10 has an outer surface 13 which is slightly tapered towards a base 14. There is formed in the outer surface 13 and the base 14 a discharge opening 15 which serves both to discharge the filtered water and to facilitate access to the cartridge portion 11 received in the conduit 10 in order to facilitate the removal thereof once used, as well as to allow the conduit 10 to be cleaned over the entire extent thereof. A beaker-like construction 20 having a closed base 21 and outer surface 22 is fitted to the exterior of the conduit 10 in the region of the discharge opening 15 so as to constitute partial closure thereof, as will be explained in greater detail below. The relative position between the beaker-like construction 20 and the opening 15 is such that the filtered water being discharged from the cartridge, or from the lower portion of the discharge opening 15, has to rise up in the beaker-like construction 20 and overflow therefrom through a discharge hole 22a which is defined between the outer surface 22 and the conduit 10, in order to be introduced into the second reservoir 12. Therefore, the beaker-like construction 20 constitutes a flow regulator for the water flowing from the first reservoir to the second in order to minimize the variation in the counter-pressure of the water being

discharged from the cartridge owing to the effect of the variation in water level in the second reservoir. This result is obtained in that there is delimited, between the beaker-like construction 20 and the conduit 10, an upward course for the water being discharged from the cartridge 11 and directed to the discharge hole so that the discharge hole 22a is close to the first reservoir with respect to the discharge of the water from the cartridge so as. to determine a counter-pressure at the outlet from the cartridge that is substantially independent of the water level in the second reservoir. The beaker-like construction is removably secured to the outer surface of the conduit 10 in order to allow it to be cleaned and to facilitate the removal of the cartridge once the filtering capacity thereof has been used. Various removable securing means are envisaged; a first example is constructed by means of a connection with slight interference between a lower portion 23 of the outer surface 22 and the corresponding outer portion of the conduit 10, to which it is fitted. Alternatively, there is provided a snap type connection (see Figure 5a), with teeth 24a on one and/or other of the connection surfaces and respective projections 24b on the respective other surface. In another alternative (see Figure 5b), there is provision for the connection surfaces to be provided with respective screws and nuts 24c in order to bring about an adjustable threaded connection.

Still with a view to adjusting the flow, there is also provision for the outer surface of the beaker 20 to be provided with one or more male threaded connection(s) which is/are able to slide telescopically over the outer surface 22 in order to extend the upward range thereof. The outer portion 23 is affected by a plurality of axially extending recesses

25, which protrude outwards so as to form channels for the passage of the filtered water. To that end, iη the region of the base 21 of the beaker-like construction, there are formed fins 26 which project radially inwards and which limit the fitting of the beaker-like construction to the conduit 10.. The operation of the filtering device 1 is as follows. Introducing water into the first reservoir 8 brings about the flow thereof, by means of gravity, towards the second reservoir 12 through the filtering material of the cartridge 11. The pressure of the water at the inlet of the cartridge 11 varies in accordance with the water level in the first reservoir. The discharge pressure from the cartridge, once the conduit 10 and the beaker-like construction are full, however, remains constant during the filtration operation. By varying the position of the beaker-like construction 20 along the conduit 10, that pressure can be adjusted as desired. In a second embodiment of the invention, the conduit 10 is open at the base 14, removably closed by a stopper 30 and the discharge hole is constituted by a hole 31 in the outer surface of the conduit 10 at a position axially remote from the stopper 30 and near the first reservoir 8. In that case, the upward course of the water being discharged from the cartridge and directed towards the discharge hole is delimited between the conduit 10 and the cartridge 11 so that that course is defined inside the conduit 10. In this case, there is further provided a flow adjuster which comprises means for adjustably closing the discharge hole. In the embodiments of Figures 6 to 10, those closing means comprise a means for adjusting the cross-section of the discharge hole, which means include one or more stopper(s) 33, 33' which is/are alternately inserted, in a replaceable

manner, in the hole 31 and which each have a calibrated hole 34, 34' of different diameter. The discharge hole in this case is defined and adjusted by the above-mentioned calibrated holes. In the case of Figure 11, the means for adjusting the cross-section of the discharge hole is constructed by a shutter 35 which has an adjustable cross- section and which is inserted in the hole 31. In that case, the shutter 35 comprises a sleeve 36 which is in turn fitted in the hole 31 and internally threaded, and in which a stopper 37 is screwed, and can therefore be progressively introduced adjustably, in which stopper 37 there is formed a passage 38 constituting an adjustable discharge hole. Varying the extent to which the stopper 37 is screwed in the sleeve 35 consequently varies the discharge hole. In both cases, it is possible that, in place of the removable stopper 30, the conduit 10 is closed at the bottom by a substantially continuous wall 14. In another variant of the invention, schematically illustrated in Figure 12, the closing means comprise at least one auxiliary discharge hole which is designated 40 and means for intercepting the hole, designated 41. The auxiliary hole in that case is positioned at the bottom of the conduit 10 which is closed or which has a removable stopper 30' (Figure 12), as indicated in the preceding embodiments, or by a bottom wall of the conduit itself. The hole 31 which defines the main discharge hole can also be formed in that wall, or that hole can be constructed elsewhere. The means 41 for intercepting the auxiliary hole are preferably of the level type, which are normally closed and able to release the hole 40 as the water level in the second reservoir increases. An example of such means provides

for a shutter 42 which is connected by means of a rod-like shaft 43 to a float 44. One or more spacers 45 are provided around the hole of the hole 40 in order to prevent the float 44, as it rises towards the cartridge 11, from intercepting the auxiliary hoje 40. It is advantageous to note how, by varying the length of the rod-like shaft 43, it is possible to vary the magnitude of the auxiliary hole 40 with respect to the level of liquid present in the second reservoir 12.

The invention thereby solves the problem addressed leading to a number of advantages. Firstly, there is obtained a decisive stabilisation of the flow rate with respect to variations in the filling states of both reservoirs. It is further possible to expel the cartridge from the conduit by pressing from below, which allows the geometry of the cartridge not to be determined from this viewpoint. Thirdly, the conduit can readily be cleaned over the entire extent thereof with an advantage in terms of the hygiene of the filtering device. It is further possible to adjust the flow of water during filtration to ensure optimum results for that operation.