FILTER FOR FLUIDS

Abstract: A filter for fluids of the type that comprises a hollow body which is closed by a head (12) and contains at least one filtration medium (13), the head comprising a hollow external cap in which through holes (15, 16, 17) are formed which are suitable to connect a corresponding number of ducts and in which a distribution element (18) with through channels can rotate. In the external dome there are at least three through holes (15, 16, 17) and the distribution element (18) is shaped so as to form at least four channels (19, 20, 21, 22): at least one first channel (19), which is a through channel which lies at right angles to this axis of rotation; at least one second channel (20) which has an exit port at an internal regional of the at least one filtration medium; at least one third channel (21) which has an exit port at a corresponding region which lies outside the at least one filtration medium; at least one fourth channel (22) which has the same configuration as one of the three preceding ones; the channels being suitable to arrange themselves in present combinations which are determined by the relative position of the dome and the distribution element, in connection with respective holes of the at least three through holes.

Description: FILTER FOR FLUIDS Technical Field The present invention relates to a filter for fluids. Pressure filters meant to filter fluids and liquids, known in the field as "cartridge filters", which use as a filtration medium a tubular element which is commonly known as filtration cartridge or as filter candle, have long been used. Background art Usual fields of application of these filters are, for example, the filtration of water for domestic uses and for technical, scientific and industrial uses. Despite the variety of their embodiments, cartridge filters are usually constituted by a hollow conveyance body which accommodates at least one filtration cartridge which is associated with a head with two ports, one for intake (inlet) and one for delivery (outlet), which can be connected to the application circuit and to the associated ducts. In turn, said head is furthermore connected hermetically to the body of the filter. Ducts and accesses to the filter are furthermore formed in the head and force, starting from the intake port and up to the delivery port, a very specific path for the fluid to be filtered, which is forced to pass through the filtration cartridge. Filtration cartridges of course oppose a certain resistance to the flow of water or of fluid in general, and accordingly a pressure drop is noted which adds to the pressure drop caused by the characteristics of the filtration system and of the corresponding ducts. This pressure drop is a typical characteristic of each filtration cartridge and can vary according to the materials of which it is made as well as according to its degree of filtration. The extent of the pressure drop must be measured when the cartridge is at the beginning of its life, and experience has shown that said pressure drop increases in value, sometimes even considerably, during its operation as the level of its clogging increases. Accordingly, the deposits retained by the filtration cartridge in the course of time heavily compromise the functionality of said cartridge and therefore must be removed in some way. Substantially two different solutions are currently commercially available: a first solution provides for non-washable or "throwaway" filtration cartridges, in which the filtered particles remain trapped mainly inside the filtering media; when the number of said particles causes excessively high pressure drops, this solution entails complete replacement of the cartridge. A second solution instead provides for washable or regenerable filtration cartridges which, by virtue of their constructive characteristics, can be cleaned and reused in a new cycle after a certain period of activity. These washable or regenerable cartridges are preferable, except for particular cases, with respect to throwaway ones, first of all because of their lower maintenance cost over time and because by virtue of their constructive characteristics they offer better filtration, ensuring a constant and precise degree of filtration over the entire surface of the filtration cartridge. Furthermore, said cartridges have a low pressure drop (and accordingly have more constant flow-rates) which increases only slightly as the level of clogging of said cartridge increases. From the point of view of operation, in most commercially available cartridges filtration, and therefore the flow of the water to be filtered, occurs from the outside toward the inside of the cartridges. This type of cartridge is termed "normal-flow" hereinafter and includes all washable filtration cartridges used to remove suspended solids (solid- liquid separation). However, some types of cartridge are commercially available for which, in order to provide correct operation, the flow of the water to be filtered, and therefore the filtration, must occur from the inside outward. These kinds of cartridge are termed "reverse-flow" cartridges hereinafter, and so-called "granular activated charcoal" cartridges are an example of this kind. The existence of the latter type of cartridge would entail, for manufacturers, the production of filters having a different indication of the intake and delivery holes; i.e., it would entail dual production, with a considerable increase in production costs. In practice, instead, dual production hardly ever occurs, and therefore these cartridges are almost always used by installing them and operating them like "normal-flow" cartridges, reducing their effectiveness. "Reverse-flow" cartridges, too, can be washable; if washing is possible, it must occur by subjecting them to a flow of water that is the reverse of the filtration flow, i.e., from the outside toward the inside of said cartridges. Washing of "normal-flow" regenerable cartridges can be performed somewhat crudely by removing the cartridge from the device and washing it with a jet of clean water while brushing it; this method can be used, in any case, only with cartridges of this type that perform a so-called "mechanical filtration". The best, most practical and effective system for washing in any case consists in cleaning the cartridges by subjecting them, without extracting them from the device, to a back-wash by means of a flow of water in the opposite direction with respect to the filtration direction. Solutions which allow to wash the cartridge are currently commercially available, and the most widely used are described hereinafter. In particular, one solution provides for true back-washing: in this type of embodiment, by operating controls which are external to the filter the flow of water is diverted toward the inside of the cartridge, the outlet is closed and the particles retained by the cartridge that have separated due to the reversal of the flow deposit themselves in the body of the filter and are discharged by means of a valve which is located on the bottom of said filter and is actuated from outside. The flow is diverted by means of pistons and/or movable walls which are built into the filter itself. Another solution instead entails a brushing action, and in practice the filter is provided with brushes which are arranged inside its body so that their respective ends touch the outside walls of the filtration cartridge. The cartridge is fixed at its two ends, which have respective shaped pivots which are connected, on the head, to an external knob and, at the other end, to a valve which is located on the bottom of the filter. By virtue of the actuation of the knob, the filtration cartridge is turned through 90° while the filter is still under pressure, so as to make the walls of the filtration cartridge rub against the brushes located inside the filter while at the same time the pivots of the end of the cartridge, by turning, close the outlet and open the discharge on the bottom of the filter. The particles detached due to the brushing action are propelled by the flow of water toward the discharge. This operation must be performed several times in order to achieve an appreciable result. Filters which combine the two types of washing described above are also commercially available. However, commercially available filters often have the drawback of not ensuring perfect separation between the filtered water and the discharge water, especially during the actuation of the moving parts, be they walls, pistons or the cartridge itself. Another remark also needs to be made regarding filters for fluids of the cartridge type that must be able to perform other tasks, and in particular must allow: to eliminate the air that remains trapped inside the filter whenever maintenance or other reasons make it necessary, after discharging the water from the filter or from the entire system downstream thereof, to refill it or restart it; to discharge the hydraulic pressure from the filter whenever it is necessary to perform maintenance or cleaning of the filter; to replace the filtration cartridge by closing the flow of water both upstream and downstream thereof; to ensure the delivery of water, even if unfiltered, during filter maintenance or during replacement of the filtration cartridge (bypass). Particularly in the domestic field, they must ensure a second service branch with unfiltered water for secondary uses, such as for example for all uses related to gardening and indoor and outdoor cleaning of the house; they must allow to clean the cartridge, if a washable cartridge is used, without having to remove it from the body in which it is accommodated and without interrupting the delivery of water, even if unfiltered. In order to solve all these requirements simultaneously, in the practice of systems design one uses a system of external bypass pipes with a drain branch and with flow control valves which divert the flow toward the filter or outside it or toward the drain branch and allow to perform back-washing and all the other above described operations. However, it is evident that although such a solution solves the operating and maintenance requirements substantially permanently, it entails an increase in the complexity of the system and entails the purchase and installation of components and more space for installation. Filters for fluids have been devised which comprise a hollow body which is closed by a head and contains at least one filtration medium; the head is in turn constituted by a hollow external cap in which two through holes are formed which are suitable to connect a corresponding number of ducts and in which a distribution element can rotate which has a first through channel, a second channel with an exit port at an internal region of said at least one filtration medium, and a third channel with an exit port at a corresponding region which is external to said at least one filtration medium. However, said filters are unable to perform the above mentioned features and requirements, since they are only capable of providing the bypass, filtration and closure of the inlet and outlet in order to perform maintenance. Disclosure of the Invention The aim of the present invention is to provide a filter for fluids which solves all the operating requirements listed above, expanding the operating possibilities of known cartridge filters without requiring external system interventions to be performed at installation, and which at least performs the functions of filtration, back-washing of the filtration medium, bypass with release of pressure and/or closure of said filter (inlet/outlet closure) with pressure release. In relation to this aim, an important object of the present invention is to allow back-washing of the filtration cartridge without having to remove it from the seat inside the body of the filter and without interrupting the delivery of water, even if unfiltered, to the user. Another object of the present invention is to provide a filter which allows delivery on a secondary water line of unfiltered water for particular uses. Another object of the present invention is to provide a filter which allows to close and fully isolate the filter upstream and downstream, with release of the pressure inside it. Another object of the present invention is to provide a filter which allows delivery of filtered water on a secondary water line. Another object of the present invention is to provide a filter which allows to deliver filtered water simultaneously both on the main line and on the secondary line. Another object of the present invention is to provide a filter which allows to deliver filtered water on the main line and at the same time deliver unfiltered water on the secondary water line. Another important object of the present invention is to provide a filter which allows to perform back-washing of the filtration cartridge, interrupting the dispensing of water to the user, and to close the filter without releasing the pressure inside the body. Another object of the present invention is to provide a filter which allows to dispense unfiltered water in bypass on both lines or to dispense unfiltered water in bypass only to the user, without releasing the pressure inside the body of the filter. Another object of the present invention is to provide a filter which is practical, efficient, constructively simple, commercially cheap, highly compact, easy to install and with maintenance reduced to a small number of simple manual operations, which meets all the above listed operating requirements. Another object of the present invention is to provide a filter which can be manufactured with known technologies and systems and at costs which are competitive with respect to commercially available filters. This aim, these objects and others which will become apparent hereinafter are achieved by a filter for fluids of the type that comprises a hollow body which is closed by a head and contains at least one filtration medium, said head comprising a hollow external cap in which through holes are formed which are suitable to connect a corresponding number of ducts and in which a distribution element can rotate about its own axis, said distribution element being shaped like a solid of revolution with through channels, said filter being characterized in that in said external cap there are at least three through holes and in that said distribution element is shaped so as to form at least four channels: ~ at least one first channel, which is a through channel which lies at right angles to the axis of rotation; ~ at least one second channel which has an exit port at an internal region of said at least one filtration medium; ~ at least one third channel which has an exit port at a corresponding region which lies outside said at least one filtration medium; ~ at least one fourth channel which has the same configuration as one of the three preceding ones; said channels being suitable to arrange themselves in preset combinations which are determined by the relative position of said cap and of said distribution element, in connection with respective holes of said at least three through holes. Brief description of the drawings Further characteristics and advantages of the present invention will become apparent from the description of two embodiments thereof, illustrated only by way of non-limitative example in the accompanying drawings, wherein: Figure 1 is a an axonometric view of a filter according to the invention in a first embodiment; Figure 2 is a schematic axonometric exploded sectional view of the head of the filter of Figure 1 ; Figure 3 is an axonometric view of the detail of Figure 2; Figures 4 to 8 are sectional orthographic projection views of the detail of Figure 2 in various steps of operation; Figure 9 is a sectional view, taken along the plane IX-IX of Figure 6; Figures 10 to 14 are sectional orthographic projection views of the head of a filter according to the invention, in a second embodiment, in the various operating steps. Wavs of carrying out the Invention With particular reference to Figures 1 to 9, a filter for fluids according to the invention, in a first embodiment, is generally designated by the reference numeral 10. The filter comprises a hollow body 11 which is closed by a head 12 and contains, in this case, a filtration medium which is constituted by a cylindrical cartridge 13. The head 12 comprises a hollow external cap in which three holes are formed radially; said holes are respectively designated by the reference numerals 15, 16 and 17 and are suitable to connect a corresponding number of ducts of the system, which are not shown; a distribution element 18 can rotate in said cap and is shaped, in this embodiment, so as to form two first diametrical through channels 19 and 20, two second channels, designated by the reference numerals 21 and 22, each of which has an exit port at a corresponding region located inside said cartridge 13, and two third channels, designated by the reference numerals 23 and 24 respectively, with corresponding exit ports in corresponding regions located outside the cartridge 13. The distribution element 18 can be turned in both directions by means of a knob 18a which protrudes from the cap 14, is available for actuation by the user, and can optionally be replaced with other similar means, such as for example a lever. One or more sealing means are arranged between the cap 14 and the distribution element 18 and can be, as in this model, a layer made of elastomer 18b which covers the outer surface of the distribution element 18 except for the passage holes; as an alternative, it is possible to use, for example, a series of annular gaskets or other sealing systems suitable for the purpose. The holes 15 and 17 are, in practice, holes which act as outlet and drain and are mutually interchangeable according to the installation requirements. The hole 16 is instead an inlet hole. The channels 19 to 24 are suitable, in preset combinations determined by the relative position of the cap 14 and of the distribution element 18, to arrange themselves so as to be connected to the respective holes 15, 16 and 17. Figures 4 to 8 illustrate the operating combinations related to use with "normal-flow" cartridges 13. In particular, in this embodiment the two first channels 19 and 20 mutually intersect in an X-shaped arrangement and are meant for the bypass function. The channels 21 and 22 in practice are meant to provide access to the internal region of the filtration cartridge 13 and the channels 23 and 24 are to provide access to the hollow body 11 outside the cartridge 13. Furthermore, the distribution element 18 is externally shaped like a solid of revolution which is cylindrical in the embodiment presented as an example. In practice, operation is as follows: depending on the relative rotation of the distribution element 18 and the cap 14, whose angle is limited in practice only by the diameter of the holes 15, 16 and 17, the various channels, designated by the reference numerals 19 to 24, arrange themselves, with regard to specific combinations, so as to connect to the holes 15, 16 and 17, forming various water circuits which allow to provide various operating conditions. It should also be noted that for optimum operation it is necessary to install, at least on the outlet of the filter, a one-way valve which is suitable to avoid undesirable reverse flow and/or emptying of the system connected thereto. Said valve, not shown in the figures for the sake of simplicity, can be built into the filter. Figures 4 to 8 illustrate the operating combinations related to use with "normal-flow" cartridges 13. Figure 4 illustrates the operating combination that allows water filtration. Figure 5 illustrates the operating combination that allows back-washing of the cartridge 13. Figure 6 illustrates the operating combination that allows bypass with release of the pressure inside the filter. Figure 7 illustrates the operating combination that allows to dispense unfiltered water at the drain, which is used as a secondary or auxiliary water line. Figure 8 illustrates another operating combination which allows bypass with pressure release. In practice, taking the combination related to filtration (Figure 4) as the initial position, by turning the distribution element counterclockwise, with rotations through 45 sexagesimal degrees, one obtains the positions of Figures 5 and 6, while by turning it in the opposite direction (clockwise) one obtains the positions of Figures 7 and 8. In order to use reverse-flow cartridges 13 (for example granular activated-charcoal cartridges) it is sufficient, in order to obtain the initial position (filtration function), to arrange the distribution element 18 so that it is turned through 180 sexagesimal degrees with respect to the initial position used for "normal-flow" cartridges. It is also noted that it is possible to swap the positions of the outlet and of the drain without altering the functions of the filter, bearing in mind that in this case the relative position between the cap 14 and the distribution element 18 for "normal-flow" cartridges is, in this case, the position for "reverse-flow" cartridges and vice versa. On the basis of the described structure, several versions of the filter can be produced and can be substantially grouped into two categories: — versions which provide filtration, back-washing of the filtering element and bypass with pressure release and/or filter closure (inlet/outlet closure) with pressure release (therefore three to four available functions), as in the above described example; ~ versions which in addition to providing the above provide other functions, such as for example dispensing filtered water on a secondary line, simultaneous filtration both on the main line and on the secondary line, dispensing filtered water on the main line and unfiltered water on the secondary line, et cetera. There are three types of version in both categories: ~ version types that can be used only with normal-flow filtration elements; — version types that can be used only with reverse-flow filtration elements; ~ version types that can be used with both types of filtering element (as the above described model). The limit to the number of functions that the various models can perform is dependent on the minimum breadth of each individual rotation of the distribution element with respect to the cap. The limit to this breadth is determined by the space required for each channel of the distribution element, increased by a suitable thickness which must preferably be greater than the breadth of said channel in order to avoid mixing of filtered water, unfiltered water and drain water. Accordingly, by increasing the diameter of the filter, a smaller rotation (with respect to a filter having a smaller diameter) is sufficient to obtain a rotation which is suitable to contain the dimensions of the channels of the distribution element and the above defined thickness. Therefore, building filters having a larger diameter increases the maximum number of internal channels that can be arranged in the distribution element and therefore a thoughtful arrangement of these channels allows to increase the number of functions that the filter can perform. By building a filter having a suitable diameter and by adequately arranging the internal channels of the distribution element it is possible to provide, with a single device, all the functions stated in the aim and objects of the present invention. The model proposed in Figures 1 to 9 has been studied specifically for use with a filtration element of the cartridge type, which generally has a small diameter and is suitable for small flow-rates; we chose this type of filter, despite the size difficulties, due to its wide diffusion in the most disparate applications, from the domestic field to the industrial field. It should also be noted that the diameter of the filter is also linked to the type of filtration medium to be used. With particular reference to Figures 10 to 14, a filter according to the invention, in a second embodiment which is also suitable for the most frequently occurring requirements, is generally designated by the reference numeral 100. The filter 100 comprises a hollow body, which is not shown and is entirely similar to the one described in the preceding embodiment; said body is closed by a head 101 and contains a filtration medium which is constituted, in this case, by a cylindrical cartridge which is also not shown and is fully similar to the cartridge 13. In particular, the head 101 comprises an external cap 102 in which there are three through holes 103, 104 and 105 (which act respectively as outlet, inlet and drain) and which accommodates a distribution element 106 which can rotate about its own axis and is shaped so as to form, in this case, a first through channel 107 which lies at right angles to the rotation axis, three channels 110, 111 and 112 with a common exit port 108 at a corresponding region located inside said cartridge, and a fifth channel 109 with an outlet at a corresponding region located outside the cartridge; between the outer cap 102 and the distribution element 106 there is a sealing gasket 106b which is fully similar to the gasket of the preceding model. In this case also, for optimum operation it is necessary to install, at least on the outlet of the filter, a one-way valve which is suitable to avoid unwanted reverse flow and/or emptying of the system associated therewith. Said valve, not shown in the figures for the sake of simplicity, can be built into in the filter. In practice, in this case operation is as follows: depending on the mutual rotation of the cap 102 and of the distribution element 106, various operating combinations can be obtained. Figures 10 to 14 illustrate the operating combinations related to use with "normal-flow" cartridges 13. Figure 10 illustrates the operating combination that allows filtration. Figure 11 illustrates the operating combination that allows the back- washing operation, dispensing unfiltered water to the user. Figure 12 illustrates the operating combination that allows to deliver unfiltered water to the drain (which in this case acts as auxiliary water line) and closes the outlet duct 103. Figure 13 illustrates the operating combination that allows bypass with pressure release. Figure 14 illustrates the operating combination that allows complete isolation of the filter 100, with release of the pressure inside it. In practice it has been found that the present invention has achieved the intended aim and objects. In particular, it should be noted that the filter according to the invention, despite its constructive simplicity and functional effectiveness, allows at least to provide the functions related to filtration, bypass, back-washing and closure of the filter with pressure release. It can also be used with "reverse-flow" cartridges, even if with slightly different functions: in order to use these cartridges it is necessary to swap the positions of the inlet and the outlet (and therefore the hole 103 becomes the inlet and the hole 104 becomes the outlet). Furthermore, the filter allows back-washing for both types of cartridge, eliminating the wash water by means of the drain; flow reversal and opening of the drain occur with a single operation. It should also be noted that the present invention allows to provide the bypass, for both types of cartridge, without the need to provide any external circuit, consequently eliminating the costs related to the assembly and purchase of the associated components. The bypass position also provides automatic release, which automatically activates pressure venting. The invention can also be configured so as to convert the drain into a second line provided with unfiltered water to be used for gardening or other purposes. It should also be noted that the present invention provides all the described functions without their provision requiring particular technical skills of the personnel assigned to operation. It should also be noted that the filter according to the invention has a structure by virtue of which the extent of the rotations, and therefore of the functions that it can perform, is determined only by the dimensions of the diameter of the holes of the cap and of the channels. The present invention is susceptible of numerous modifications and variations, all of which are within the scope of the same inventive concept; thus, for example, the first channels can intersect in a Y-shaped configuration. The technical details may be replaced with other technically equivalent elements. The materials and the dimensions may be any according to requirements. The disclosures in Italian Patent Application No. PD99A000119 from which this application claims priority are incorporated herein by reference.

Claims: CLAIMS 1. A filter for fluids of the type that comprises a hollow body which is closed by a head and contains at least one filtration medium, said head comprising a hollow external cap in which through holes are formed which are suitable to connect a corresponding number of ducts and in which a distribution element with through channels can rotate about its own axis, said filter being characterized in that in said external cap there are at least three through holes and in that said distribution element is shaped so as to form at least four channels: ~ at least one first channel, which is a through channel which lies at right angles to the axis of rotation; — at least one second channel which has an exit port at an internal region of said at least one filtration medium; ~ at least one third channel which has an exit port at a corresponding region which lies outside said at least one filtration medium; ~ at least one fourth channel which has the same configuration as one of the three preceding ones; said channels being suitable to arrange themselves in preset combinations which are determined by the relative position of said cap and of said distribution element, in connection with respective holes of said $at least three through holes. 2. The filter according to claim 1, characterized in that it comprises at least two first channels which are arranged so as to mutually intersect. 3. The filter according to claim 1, characterized in that each one of said second channels has an exit port in common with the others of the same type, said exit port being located at a corresponding region which is internal to said cartridge. 4. The filter according to one or more of the preceding claims, characterized in that said distribution element is externally shaped like a solid of revolution. 5. The filter according to one or more of the preceding claims, characterized in that said filtration medium is constituted by a filtration cartridge. 6. The filter according to one or more of the preceding claims, characterized in that it comprises, at least on the outlet, a one-way valve. 7. The filter according to one or more of the preceding claims, characterized in that said one-way valve is integrated therein.

Inventors: MINICHIELLO BERARDINO, MINICHIELLO LUIGI, MINICHIELLO, BERARDINO, MINICHIELLO, LUIGI
Applicants: MINICHIELLO BERARDINO, MINICHIELLO LUIGI, MINICHIELLO, BERARDINO, MINICHIELLO, LUIGI
Application year: 2000
Main classification: B01D29
IPC codes: B01D29, B01D46, F16K11