FESTA, Aldo (Via S. Mercadante 56, Pesaro, I-61122, IT)
| CLAIMS 1) . A liquid filter device (1) for use in water plants, comprising: a chamber (2); a filter cartridge (3) arranged internally of the chamber (2), comprising a wall (4) provided with openings (5) for filtering a liquid; scraping means (6); a liquid outlet (7); the filter cartridge (3) and the scraping means (6) being reciprocally arranged and mobile in such a way that the scraping means (6) can scrape the wall (4) of the filter cartridge (3) in order to remove material deposited thereon; characterised in that: the chamber (2) is arranged such as to receive the liquid to be filtered; the filter cartridge (3) is internally connected to the liquid outlet (7) such that the liquid to be filtered contained in the chamber (2) is filtered across the wall (4) of the filter cartridge (3) and reaches the liquid outlet (7); and in that the scraping means (6) are arranged externally of the filter cartridge (3) and internally of the chamber (2). 2) . The device (1) of the preceding claim, comprising a discharge outlet (8) of the liquid communicating with the chamber (2). 3). The device (1) of any one of the preceding claims, wherein the scraping means (6) comprise a brush (6) and/or a blade (6). 4). The device (1) of the preceding claim, wherein the wall (4) of the filter cartridge (3) has a cylindrical conformation and wherein the brush (6) and/or the blade (6) is arranged such as to act tangentially with respect to the wall (4) of the filter cartridge (3). 5). The device (1) of any one of the preceding claims, comprising a turbine impeller (19) having an outlet for the liquid to be filtered which is directly connected to the inlet of the chamber (2). 6). The device (1) of any one of the preceding claims, comprising a neutralising electrode (30) located internally of the chamber (2) such as to prevent precipitation of limescale. |
TECHNICAL FIELD
The present invention relates to the technical sector of filter devices for liquids in use in water plants.
The water introduced into domestic and industrial water supply grids usually comprises a certain quantity of impurities, such as sand, sludge, rust and limescale, the presence of which can create drawbacks and damage to the water supply grids themselves. To obviate this drawback, filter devices are installed, located for example upstream of the water supply grid, which devices retain the impurities present in the water.
BACKGROUND ART A filter device of known type internally comprises a filter cartridge which can be made of a textile material, or a synthetic or metal net, or stainless steel, etc: the filter cartridge is usually cylindrical and tubular, and the relative lateral wall is provided with through-holes for filtering the water.
As a consequence, however, during the filtering of the water the solid impurities retained by the filter cartridge tend to deposit on the filter wall and progressively clog the through-holes thereof, up to the pont of requiring replacement or periodic cleaning of the filter cartridge.
To manually clean the filter cartridge it is necessary to open it, wash it and brush it. Periodic cleaning of the filter cartridge should be done as often as possible in order to prevent the impurities retained thereby stagnating for a long time on the filter wall, because that gives rise to limescale encrustation that is difficult to remove after a considerable time. The impurities that remain attached to the filter cartridge between one clean and another thicken and increase their adherence, up until they can also become unremovable. With use, the number of blocked through-holes becomes so high as to require replacement of the filter cartridge.
To obviate this drawback, filter devices are known that perform an automatic cleaning of the cartridge together with the filtering of the water.
An example is described in document GB 2 294 887 which discloses a liquid filter device comprising: an inlet for the water to be filtered; a turbine impeller connected to the water inlet; a filter cartridge having a cylindrical-tubular shape, a waterproof bottom wall, an axial opening communicating with the outlet of the turbine impeller such as to receive water to be filtered internally thereof and a lateral wall provided with through-holes for filtering the water; a chamber in which the filter cartridge is contained, which chamber receives the filtered water supplied by the filter cartridge; an outlet of the filtered water connected to the chamber.
The filter device further comprises blades or brushes arranged internally of the filter cartridge. The turbine impeller is predisposed such as to draw the blades or brushes and/or the filter cartridge in rotation with the aim of creating a turbulence in the water to be filtered, contained internally of the filter cartridge, such as to reduce the quantity of solid particles which can deposit on the internal surface of the lateral wall of the filter cartridge. In a first embodiment, the filter cartridge is rotatable with respect to the chamber and is drawn in rotation by the turbine impeller; the brushes originate from the internal surface of the lateral wall of the filter cartridge; the filter cartridge and the brushes are solidly constrained to one another and are mobile with respect to the chamber. ln a second embodiment, the filter cartridge is solidly constrained to the chamber, while a shaft is provided, moved by the turbine impeller which passes axially through the filter cartridge and which bears the brushes; the brushes are arranged internally of the filter cartridge and rotate with respect to the filter cartridge and the chamber. The brushes can have an extension which is such as to brush the internal surface of the lateral wall of the filter cartridge in order to exert a mechanical action of removal of the impurities which can deposit on the lateral wall.
Thus there is a smaller number of impurities depositing on the lateral wall of the filter cartridge: consequently the filter device described in GB 2 294 887 enables less maintenance of the filter cartridge and longer working life thereof.
A drawback of the above-described invention lies in the fact that the impurities which do not deposit on the internal surface of the lateral wall of the filter cartridge remain in suspension internally the filter cartridge itself. The quantity of these suspended impurities increases with the use of the filter device; it is therefore necessary to periodically access the chamber, open the filter cartridge and remove the impurities contained therein, then to re-close the filter cartridge - all of which is considerably time-consuming.
DISCLOSURE OF INVENTION
The aim of the present invention is to obviate the above-described drawback.
The aim is attained with a filter device for liquids as in claim 1 , comprising: a chamber, a filter cartridge arranged internally of the chamber, comprising a wall provided with openings for filtering a liquid; scraping means; a liquid outlet; the filter cartridge and the scraping means being arranged with respect to one another and being reciprocally mobile such that the scraping means can scrape the filter cartridge wall such as to remove material deposited thereon; characterised in that: the chamber is arranged such as to receive the liquid to be filtered; the filter cartridge is internally connected to the liquid outlet; such that the liquid to be filtered contained in the chamber is filtered across the wall of the filter cartridge and reaches the liquid outlet; and in that the scraping means are arranged externally of the filter cartridge and internally of the chamber. The flow of water to be filtered thus reaches the chamber; then the water is filtered by passing through the wall of the filter cartridge; finally the filtered water is conveyed towards the liquid outlet. The scraping means act on the surface of the filter wall which faces the chamber, preventing the depositing of impurities thereon. As a consequence, the impurities remain in suspension internally of the chamber and no longer internally of the cartridge: the removal of the impurities is advantageously much more simple and rapid as it is sufficient to access the chamber. In the prior art it was necessary to access the chamber and open the filter cartridge, clean it and close it. The filter device of the invention preferably comprises a discharge outlet for the liquid which is in communication with the chamber. In this way, it is not necessary to access the chamber with mechanical instruments, such as screwdrivers and the like, but it is sufficient to act from the outside on the discharge outlet in order to periodically drain the liquid contained in the chamber and containing the impurities to be eliminated. The periodic manual operations on the filter device can advantageously be reduced drastically and are only required for cleaning or replacement of the filter cartridge.
Means can be provided to act automatically, or remotely, on the discharge outlet of the liquid such as to avoid the necessity for an operator to perform the task in loco. A single-acting valve, for example, can be provided at the discharge opening, such as to enable discharge of the liquid contained in the chamber towards the outside.
In a preferred embodiment, the scraping means comprise a brush and/or a blade and the wall of the filter cartridge has a cylindrical conformation; the brush and/or the blade is arranged such as to act tangentially with respect to the wall of the filter cartridge. This is particularly advantageous as there is a reduction in friction between parts in relative motion, i.e. between the brush and/or the blade and the wall of the filter cartridge; in the prior art, the brushes have a radial orientation and it was not possible for them to have a tangential arrangement because the brushes were arranged internally of the filter cartridge. Further, the less friction determined between the brush and/or the blade and the wall of the filter cartridge also causes less wear on both the brush and/or the blade and the filter cartridge wall.
BRIEF DESCRIPTION OF THE DRAWINGS
Specific embodiments of the invention, and advantageous technical-functional characteristics correlated to the embodiments, will be described herein below in the present description, in accordance with what is set out in the claims and with the aid of the accompanying figures of the drawings, in which: figure 1 illustrates an axial section of a liquid filter device of the present invention, in a first embodiment; figure 2 is the view along section ll-ll of figure 1 , in enlarged scale; figure 3 is an exploded view of the device of figure 1 ; figure 4 illustrates an axial section of a liquid filter device of the present invention, in accordance with a second embodiment; figure 5 is the view of section V-V of figure 4, in enlarged scale; figure 6 is an exploded view of the device of figure 4; figure 7 illustrates the axial section of a liquid filter device of the present invention, in a third embodiment; figure 8 is the view of section VIII-VIII of figure 7, in enlarged scale; figure 9 is an exploded view of the device of figure 7.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to the accompanying figures of the drawings, 1 denotes in its entirety a liquid filter device of the present invention, comprising: a chamber 2, a filter cartridge 3 arranged internally of the chamber 2, comprising a wall 4 provided with openings 5 for filtering a liquid; scraping means 6; a liquid outlet 7; the filter cartridge 3 and the scraping means 6 being arranged with respect to one another and being reciprocally mobile such that the scraping means 6 can scrape the filter cartridge wall 4 of the filter cartridge 3 such as to remove material, in particular impurities, deposited thereon. Further, the chamber 2 is arranged such as to receive the liquid to be filtered; the filter cartridge 3 is internally connected to the liquid outlet 7; such that the liquid to be filtered contained in the chamber 2 is filtered across the wall 4 of the filter cartridge 3 and reaches the liquid outlet 7; the scraping means 6 are arranged externally of the filter cartridge 3 and internally of the chamber 2.
The device 1 preferably comprises a discharge outlet 8 of the liquid which communicates with the chamber 2; the liquid contained internally of the chamber 2, therefore, can be expelled to the outside by opening the discharge opening 8. Impurities which remain suspended in the liquid contained in the chamber 2 can thus be eliminated via the discharge outlet 8. A single-acting valve 77 can be located at the discharge outlet 8 in order to enable the liquid contained in the chamber 2 to be expelled to the outside.
The scraping means 6 comprise a brush 6 and/or a blade 6. The wall 4 of the filter cartridge 3 preferably has a cylindrical conformation and the brush 6 and/or the blade 6 is arranged such as to act tangentially with respect to the wall 4 of the filter cartridge 3. This is particularly advantageous as there is a reduction in the friction between parts in reciprocal relative motion, i.e. between the brush 6 and/or the blade 6 and the wall 4 of the filter cartridge 3. Further, the lower friction between the brush 6 and/or the blade 6 and the wall 4 of the filter cartridge 3 also causes less wear both on the brush 6 and/or the blade 6 and on the wall 4 of the filter cartridge 3.
The filter device 1 further comprises: a liquid inlet 20; and a turbine impeller 19 the inlet of which is connected to the liquid inlet 20 and the outlet of which communicates directly with the chamber 2, such that the entering liquid to be filtered through the liquid inlet 20 passes through the impeller and activates it, and then reaches the chamber 2. The blades of the turbine impeller 19 are activated by the pressurised liquid which enters from the liquid inlet 20 of the filter device 1 such as to draw the filter cartridge 3 in rotation (first and second embodiments of the invention illustrated in figures 1-3 and 4-6 respectively) or the scraping means 6 in rotation (third embodiment illustrated in figures 7-9), as will emerge herein below.
The water exiting from the turbine impeller 19 and which enters the chamber 2 takes on a swirling cyclone motion, such as to realise a turbulence internally of the chamber 2: thanks to this turbulence the impurities present in the chamber 2 tend advantageously to remain suspended more easily; in other words, it is more difficult for these impurities to deposit on the wall 4 of the filter cartridge 3. It is noteworthy that the depositing of these impurities on the wall 4 of the filter cartridge 3 is further obstructed by the scraping action of the scraping means 6, such that an advantageous combined and synergic effect is obtained such as to prevent stable and permanent depositing of impurities on the wall 4 of the filter cartridge 3. The turbulence inside the chamber 2 is due to the direct connection between the outlet of the turbine impeller 19 and the inlet of the chamber 2; the water exiting from the turbine impeller 19 takes on a swirling motion by effect of the interaction of the pressurised water with the blades of the turbine impeller 19.
In the prior art there is not a direct connection of the above-described type and the turbulence was obtained only with the use of rotating brushes moved by the impeller of the turbine; this required greater masses to be drawn in rotation by the turbine impeller.
A more detailed description now follows of the embodiments illustrated in the figures, in non-limiting forms of the above-described invention and as claimed herein below.
With specific reference to figures 1-3, the liquid filter device 1 comprises a main housing 38 internally of which the filter cartridge 3 is arranged; the main housing 38 has a cylindrical and substantially tubular conformation and is conformed such as to internally contain all the elements which form the filter device 1 of the invention.
The filter device 1 further comprises an inlet mouth 9, destined to be connected to a first end 10 of a first tube which supplies liquid to be filtered to the filter device 1 , and an outlet mouth 12, destined to be connected to a second end 1 of a second tube which has to be supplied with filtered liquid from the filter device 1. The first tube and the second tube are for example integrated parts of a water supply grid, not illustrated, and the liquid is, for example, water.
The inlet mouth 9 and the outlet mouth 12 are provided on the external surface thereof with a first seal 13 gasket and respectively a second seal gasket 14, each adhering to the internal surface of the main housing 38.
A first transversal groove 15 and a second transversal groove 16 are fashioned along the internal surface of the main housing 38. the first transversal groove 15 is made in proximity of the inlet mouth 9 and houses a first seeger ring 17 which prevents detaching of the inlet mouth 9 from the main housing 38, while the second transversal channel 16 is made in proximity of the outlet mouth 12 and houses a second seeger ring 8 which prevents detachment of the outlet mouth 12 from the main housing 38.
The first transversal groove 15, the second transversal groove 16, the first seeger ring 17 and the second seeger ring 18 form blocking means of the inlet mouth 9 and the outlet mouth 12 to the main housing 38.
The filter device 1 further comprises: a first bushing 21 fixed to the inlet mouth 9 at the internal side thereof; and a second bushing 22 fixed to the outlet mouth 12 at the internal side thereof. The first bushing 21 and the second bushing 22 rotatably support the filter cartridge 3.
The turbine impeller 19 is interposed between the inlet mouth 9 and the first bushing 21 , on the one side, and the filter cartridge 3 and the chamber 2 on the other side.
The filter cartridge 3 has a cylindrical and tubular form and exhibits through- holes 5 on the relative wall 4 for filtering the water. A first end of the filter cartridge 3 is closed by the turbine impeller 19, while the second end is sealedly coupled with a disc 23, also an integrated part of the device 1 of the invention.
The turbine impeller 19 is provided with an internal conduit 24, the inlet of which is positioned on the opposite side to the side the filter cartridge 3 is located at, while the outlet faces the side which interfaces with the filter cartridge 3.
The inlet of the turbine impeller 19 comprises a circular hole the centre of which is arranged along the longitudinal axis of the filter cartridge 3, while the outlet of the turbine impeller 19 comprises an annular opening, the internal diameter of which is greater than the external diameter of the filter cartridge 3 and the external diameter of which is smaller than the diameter of the main housing 38.
An annular series of blades is located along the internal conduit 24, shaped in such a way that when the pressurised water hits them during its passage internally of the internal conduit 24, the turbine impeller 19 is set in rotation.
The turbine impeller 19 is provided, on the side facing towards the first mouth 21 , with a first nozzle 26 rotatably inserted internally of the first bushing 21. The second end of the filter cartridge 3, as mentioned, is sealedly coupled to the disc 23; a second nozzle 27 originates from the disc 23, which second nozzle 27 affords a plurality of through-holes or conduits which are orientated parallel to the longitudinal axis of the filter cartridge 3. The second nozzle 27 is fixed to the disc 23, for example by means of glue, and is inserted rotatably internally of the second bushing 22.
The chamber 2 is delimited by the internal walls of the main housing 38, by the impeller turbine 19 and by the outlet mouth 12.
The scraping means 6 are constituted by a brush 6 fixed to the internal wall 4 of the main housing 38 such that the bristles scrape against the external surface of the lateral wall 4 of the filter cartridge 3 when the filter cartridge 3 is rotating.
The brush 6 is preferably positioned such that the terminal tract of the bristles thereof is arranged tangentially with respect to the point of contact thereof against the external surface of the lateral wall 4 of the filter cartridge 3, as can be seen in figure 2.
The filter device 1 further comprises a neutralising electrode 30 located internally of the chamber 2 with the aim of preventing precipitation of limescale. The discharge channel 8 is made in the main housing 38 and is arranged on the bottom of the channel 2, for example downstream of the brush 6.
The single-acting valve 77 is installed at the discharge outlet 8, which enables the impurities contained in the chamber 2 to exit therefrom and be conveyed into a discharge conduit, not illustrated. As can be seen in figure 1 in particular, the axis of the housing coincides with the axis of the first tube and the axis of the second tube; the filter device 1 can therefore assume a horizontal trim if the first tube and the second tube are horizontally arranged. Although the functioning of the filter device 17 of the invention is obvious from the above description, a functional description thereof now follows.
The water to be filtered is supplied by the first liquid inlet tube 20 of the device 1 ; the water then crosses the inlet mouth 9 and the internal conduit 24 of the turbine impeller 19 and strikes the blades with a consequent rotation of the turbine impeller 19 and the filter cartridge 3. The water exits the turbine impeller 19 and returns to the chamber 2; from the chamber 2 the water crosses the through-holes 5 of the lateral wall 4 of the filter cartridge 3 and reaches the inside of the filter cartridge 3, then to be conveyed along the conduits of the second nozzle 27 before exiting from the filter device 1 through the outlet nozzle 12.
The impurities are retained on the external surface of the lateral wall 4 of the filter cartridge 3; the filter cartridge 3 is constantly in movement and it is therefore subjected to the scraping action of the brush 6 which facilitates the detachment of the impurities from the external surface.
The impurities can be automatically removed from the discharge outlet 8, at periodic time intervals or according to the amount of water crossing the filter device 1.
Figures 4-6 illustrate a second embodiment of the filter device 1 of the invention, in which similar or identical components to those illustrated and discussed with reference to the first embodiment have been denoted using the same numerical references.
The first and the second nozzles 27 have been functionally replaced with a shaft 28 the ends of which rotatably engage respectively with a blind hole afforded in the inlet mouth 9 and the outlet mouth 12; the shaft 28 is solidly constrained to the cartridge and the turbine impeller 19.
Figures 7-9 illustrate a third embodiment of the filter device 1 of the invention, in which similar or identical components to those illustrated and discussed with reference to the first embodiment have been denoted using the same numerical references.
In this case the filter cartridge 3 is solidly constrained to the main housing 38, while three brushes 6 are comprised, angularly equidistanced with respect to the longitudinal axis of the filter cartridge 3 which are solidly constrained to the turbine impeller 19 and rotate there-with such as to scrape the external surface of the wall 4 of the filter cartridge 3. In particular, a tubular casing 29 is provided, fixed to the turbine impeller 19 and from the surface of which the brushes 6 originate.
The above is intended as a non-limiting example of the invention, and any constructional variants are intended to fall within the protective ambit of the present technical solution, as claimed herein below.