System for improving cleaning for disc filters and disc filter

Abstract

The invention describes a system (1) for improving cleaning for disc filters, which comprises a perforated central tube (5) and a lower valve (6). In filtering mode, when water exits through an outlet port (S), the valve (6) adopts an open position allowing the water to flow through a central hole (61c) and peripheral holes (61p). In cleaning mode, when the water enters through the outlet port (S), it pushes the obturator (62) vertically upwards into a closed position, such that the water flows through the central hole (61c) only, passes through a turbine (4), thereby rotating the tube (5) attached to a rotor, reaches the space inside the tube (5) and is expelled under pressure in an outward radial direction through perforations (51), thus improving the cleaning of the filter.

Description

[0001] CLEANING IMPROVEMENT SYSTEM FOR RING FILTER AND RING FILTER EQUIPPED WITH SUCH SYSTEM

[0002] DESCRIPTION

[0003] OBJECT OF THE INVENTION

[0004] The present invention falls within the field of filtration of wastewater, industrial and / or agricultural waters.

[0005] A first object of the present invention is a new system that can be installed in a ring filter to improve the performance of the cleaning cycle.

[0006] A second object of the present invention is a ring filter provided with a system as described above.

[0007] BACKGROUND OF THE INVENTION

[0008] A ring filter is based on a set of micro-slotted rings that are stacked on top of each other to form an annular filter element.

[0009] Figs. 1A, 1B and 2 show schematically a ring filter (FA) of this type where its main components can be seen. The ring filter (FA) has a filtering element (EF) formed by stacking a set of rings (A), or discs, which have a series of micro-slots arranged on their main faces. The rings (A) are arranged around a central cylindrical frame (AC) that supports them. A cover (C) of essentially cylindrical shape houses inside the filtering element (EF) formed by the rings (A) stacked around the central frame (AC). Thus, in the ring filter (FA), the filtering element (EF) has an essentially cylindrical shape that separates a peripheral space (EP), radially exterior, from a central space (EC), radially interior.The ring filter (FA) further comprises a threaded cap on the upper part of the central cylindrical frame (AC) which, during normal operation of the filter (FA), exerts an axial compression force that compresses the rings (A) of the filter element (EF) against each other. Thanks to this configuration, for the water to be filtered to pass from one of these spaces to the other, it must move in a radial direction passing through the micro-slots of the filter element (EF) that are formed between the discs. The radially outer peripheral space (EP) communicates with an inlet connection (E) and the radially inner central space (EC) communicates with an outlet connection (S).

[0010] A ring filter (RF) of this type mainly has two different operating modes:

[0011] - Filtering mode (Fig. 1A)

[0012] During filtration mode, the water to be filtered is introduced through the inlet (E), thus reaching the radially outer peripheral space (EP) of the filter (FA). Appropriate guidance of the water, for example through baffles, causes it to enter the peripheral space (EP) with a rotary motion. Then, due to the pressure difference, the water flows towards the central space (EC), radially inner space of said filter element (EF), having to pass through the micro-slots of the stacked rings (A) that make up the filter element (EF). These micro-slots allow the passage of water but block the passage of impurities, which are trapped either on the outer surface of the filter element (EF) or, if they are sufficiently small, at some point inside the micro-slots that traverse it. Finally, the water exits the central space (EC) through the outlet (S) of the filter (FA).

[0013] This operating mode continues until the amount of impurities trapped by the filter element (EF) is such that there is a significant pressure drop between the inlet (E) and outlet (S). At that point, the cleaning mode described below is automatically switched to.

[0014] - Cleaning mode (Fig. 1 B)

[0015] In cleaning mode, the position of the system valves is modified to reverse the flow direction. Therefore, water now enters through the outlet (S), i.e., directly into the radially inner central space (EC) of the filter (FA). After passing through the filter element (EF) in the opposite direction to that described in filtering mode, it reaches the peripheral space (EP) and finally exits through the inlet port (E).

[0016] The reversal of the flow direction causes the impurities that had been trapped in the rings (A) that make up the filter element (EF) to be expelled towards the peripheral space (EP) and evacuated through the inlet port (E).

[0017] Although these types of ring filters work properly, sometimes the cleaning mode fails to properly evacuate all the impurities trapped in the filter element.

[0018] In short, there is a need for improvements in the filter cleaning system in this field of technology.

[0019] DESCRIPTION OF THE INVENTION

[0020] The inventors of the present invention have developed a system to improve the performance of the cleaning phase of a ring filter.

[0021] This document describes the system taking into account the orientation it would have when installed in a ring filter in its most common position, where the vertical direction coincides with the axial direction of the various elements comprising it. The terms "upper," "lower," and similar terms should be interpreted in accordance with this position, which is also the one shown in all the figures in this application.

[0022] First aspect: cleaning system

[0023] A first aspect of the invention is directed to a system for improving the cleaning phase of a ring filter. This system essentially comprises the following elements: a central frame, a bearing, a turbine, a tube, and a valve. Each of these elements is described in greater detail below. a) Central frame

[0024] This is a cylindrical frame configured to support a plurality of micro-slotted rings stacked axially. This frame has a lower end configured to couple to a water outlet port of the ring filter. It is a central frame similar to those normally used in this type of filter to support the stack of filter rings. It is usually formed by a set of elongated elements that allow water to pass between its interior and exterior spaces. b) Support bearing

[0025] As will be described later, this is a small bearing that allows the tube inside the cylindrical frame to rotate when the ring filter is cleaned. The bearing has an outer ring fixed to an upper end of the central frame. c) Turbine

[0026] The turbine is the element that provides support to the opposite end of the tube to allow its rotation during the cleaning phase of the ring filter. The turbine has a stator attached to the lower end of the central frame. d) Tube

[0027] The tube is housed inside the central frame and comprises perforations distributed over its surface. More specifically, the tube has an upper end fixed to an inner ring of the bearing and a lower end fixed to a turbine rotor. Thus, when the water flow goes from bottom to top during the filter cleaning phase, it passes through the turbine rotor and causes it to rotate, thereby also causing the tube to rotate. In a preferred embodiment of the invention, the tube's perforations are in the form of an inclined slot to project the water evenly toward the inner wall of the stack of rings, overlapping one slot with another. e) Valve

[0028] The valve is arranged at the lower end of the central frame, and comprises the following components:

[0029] - Body: The body is coupled to said lower end of the central frame and comprises a central hole in communication with an interior space of the tube and a plurality of peripheral holes in communication with a space outside the tube but inside the central frame. For example, in a particularly preferred embodiment of the invention, the body is in the form of an annular disc whose central opening forms the central hole and which is also provided with the peripheral holes.

[0030] - Shutter: The shutter is configured to alternate between an upper position in which it seals the peripheral holes and a lower position in which it does not seal the peripheral holes. To this end, in a preferred embodiment of the invention, it is shaped like an annular disk lacking holes except for its central opening. Naturally, it also has the same dimensions as the annular disk that makes up the body. Thus, when both are compressed against each other, the shutter covers the peripheral holes. However, the central hole of the shutter and body coincide, thus allowing water to pass through at all times.

[0031] - Spring: The spring connects the shutter to the body so that it applies a continuous upward force that tends to move the shutter towards its upper position.

[0032] Thanks to this configuration, the valve works as follows during filter operation.

[0033] During the filter's filtration mode, when water flows out through the outlet port, the valve assumes its open position, allowing water to flow through the central and peripheral orifices. That is, during filtration mode, water normally exits through the outlet port, and therefore adopts a downward axial direction. Thus, the force exerted by the water on the plug is opposite to that exerted by the spring, thus causing the plug to descend against the force of the spring. In this situation, since the water filtered by the stack of rings will remain mostly in the space between the cylindrical frame that supports said rings and the tube located inside, said water will exit mainly through the peripheral orifices of the valve body.

[0034] During filter cleaning mode, however, when water enters through the outlet port, the water flow pushes the shutter vertically upward and combines with the force exerted by the spring, causing the shutter to assume its closed position. Thus, water flows only through the central hole, passes through the turbine by rotating the tube attached to its rotor, reaches the interior space of the tube, and is expelled under pressure in a radial outward direction through the perforations. The projection of water through the perforations, with the tube rotating continuously during this phase, improves filter cleaning.

[0035] Second aspect: ring filter

[0036] A second aspect of the present invention is directed to a ring filter comprising a cleaning improvement system as described in the preceding paragraphs.

[0037] BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figs. 1A and 1B show an example of a prior art ring filter respectively during a filtering phase and during a cleaning phase.

[0039] Fig. 2 shows another example of a partially disassembled ring filter.

[0040] Fig. 3 shows an exploded view of an example of a system according to the present invention.

[0041] Fig. 4 shows a perspective view of a lower portion of the system of the present invention where the valve can be seen in the open position.

[0042] Fig. 5 shows another perspective view of the lower portion of the system of the present invention where the valve can be seen in the closed position.

[0043] PREFERRED EMBODIMENT OF THE INVENTION

[0044] An example of a cleaning improvement system (1) for ring filters according to the present invention is described below, with reference to the attached figures where the different elements that comprise it can be seen.

[0045] The system (1) comprises a central frame (2) of essentially cylindrical shape on which the filter rings (A) are normally arranged stacked vertically, that is, in the axial direction. The frame (2) is formed in this example by four vertical bars connected by horizontal rings, although it could adopt any other configuration as long as it is sized to support the rings (A) and has openings distributed over its entire surface to allow the free passage of water through it in a radial direction.

[0046] The tube (5) is arranged inside the central frame (2). The tube (5) has a smaller diameter than the central frame (2), such that a space in the form of a prism with an annular section is generated between them. The tube (5) is connected to the central frame (2) at both ends through two elements that allow said tube (5) to rotate relative to the central frame (2). Specifically, the upper end of the tube (5) is fixed to the inner ring of a bearing (3) whose outer ring is fixed to the central frame (2), specifically to a piece that constitutes the upper end (2) of said central frame (2). In this example, this piece is fixed to the rest of the central frame (2) by means of a thread. For its part, the lower end of the tube (5) is fixed to the rotor of a turbine (4) whose stator is fixed to the lower end (21) of the central frame (2).Thanks to this configuration, when a flow of water enters the interior space of the tube (5) in a vertical upward direction through the turbine rotor (4), it causes the tube (5) to rotate relative to the central frame (2).

[0047] A valve (6) is fixed to the lower end (21 ) of the central frame (2). The valve (6) has a body (61 ) in the form of an annular disc provided with a central hole (61c) and a set of peripheral holes (61 p). When this body (61 ) is fixed to the lower end (21 ) of the central frame (2), the central hole (61 c) communicates the outlet (S) of the filter with the space inside the tube (5) and the peripheral holes (61 p) communicate the outlet (S) of the filter with the space between the tube (5) and the central frame (2). Note that, although not shown in these figures, the outlet (S) of the filter is connected to the lower end of the filter, in a manner similar to that shown in Figs. 1 and 2 corresponding to filters according to the prior art.

[0048] The valve (6) further comprises a shutter (62) which is also in the form of an annular disc, although in this case lacking peripheral holes of any kind. The shutter (62), naturally, has the same dimensions as the body (61 ), such that when both are compressed against each other, the shutter (62) covers the peripheral holes (61 p) of the body (61 ), thus preventing the passage of water between the outlet (S) and the space between the tube (5) and the cylindrical frame (2). The central opening of the shutter (62), on the contrary, by coinciding with the central hole (61c) of the body (61 ), allows the passage of water between the outlet (S) and the space inside the tube (5). To improve the seal, an upper face of the shutter (62) can have a rubber coating.

[0049] The shutter (62) is connected to the body (61) of the valve (6) by means of a spring (63), which in this example takes the form of a series of spring-loaded screws. This spring (63) is configured so that it exerts a constant force oriented in an upward axial direction, that is, a constant force that tends to keep the shutter (62) in a closed position which is attached to the body (61).

[0050] Thus, when the filter operates in a filtering phase, as previously described in this document, the water flow enters through an inlet (E) located on one side of the cover (C). The water then passes into the space located between the filter element (EF) formed by the stack of rings (A) and the cover (C), passes radially through the stack of rings (A) and the central frame (2) on which said rings (A) are arranged, and reaches the space inside the central frame (2). A small part of the water could then pass through the perforations (51 ) to the inside of the tube (5), although the majority will remain in the space between said tube (5) and the central frame (2). The water flow then adopts a downward axial direction to pass mostly through the peripheral holes (61 p) of the valve (61 ), although it also partly through the central hole (61 c).In this sense, the downward force exerted by the water on the shutter (62) is in the opposite direction to that exerted by the spring (63), so that the shutter (62) remains in the lower open position. Ultimately, the water exits through the outlet duct (S). Fig. 4 shows the valve (6) in the open position.

[0051] On the contrary, when the filter operates in a cleaning phase, the direction of the water flow is reversed. The water then enters through the outlet duct (S), that is, it enters in an axial direction and vertically upwards according to the figures. The first obstacle that the water encounters is the lower face of the shutter (62), and therefore exerts a vertical force upwards on it. The sum of this force with the force exerted by the spring (63) in the same direction and sense moves the shutter (62) from its lower open position to its upper closed position. In the upper position, as mentioned, the shutter (62) is compressed against the body (61 ), thus sealing the peripheral holes (61 p). Consequently, the water flow can only pass through the central hole (61 c) of the body (61 ), thus reaching only the space inside the tube (5).This water then passes in a radial direction through the perforations (51 ) of the tube (5) and is thus, due to the effect of pressure, projected radially against the stack of rings (A). The sealing of the peripheral holes (61 p) by the shutter (62) also ensures that the space between the tube (5) and the central frame (2) is not filled with water, which would prevent the water projected by the tube (5) from impacting against the stack of rings (A). Furthermore, when the water passes through the rotor of the turbine (4), the tube (5) is caused to rotate. The final effect of this entire process is that the tube (5) rotates while emitting, through the perforations (51 ), a plurality of radially oriented pressurized water jets. These rotating radial pressurized water jets impact the radially inner side of the stack of rings (A), significantly improving the cleaning performance.

Claims

CLAIMS 1. Cleaning improvement system (1) for a ring filter, characterized in that it comprises: a) a cylindrical central frame (2) configured to support a plurality of micro-grooved rings (A) stacked in an axial direction, said central frame (2) having a lower end (21) configured to couple to a water outlet port (S) of the ring filter; b) a bearing (3) having an outer ring fixed to an upper end (22) of the central frame (2); c) a turbine (4) having a stator fixed to a lower end (21) of the central frame (2); d) a tube (5) provided with perforations (51) distributed over its surface, housed inside the central frame (2), the tube (5) having an upper end fixed to an inner ring of the bearing (3) and a lower end fixed to a rotor of the turbine (4); ye) a valve (6) arranged at the lower end (21) of the central frame (2), wherein said valve (6) comprises: - a body (61 ), coupled to said lower end (21 ) of the central frame (2), comprising a central hole (61c) in communication with an interior space of the tube (5) and a plurality of peripheral holes (61 p) in communication with a space outside the tube (5) but inside the central frame (2), - a shutter (62) configured to alternate between an upper position in which it closes the peripheral holes (61 p) and a lower position in which it does not close the peripheral holes (61 p); and - a spring (63) connecting the shutter (62) to the body (61) so as to apply a continuous upward force tending to move the shutter (62) towards its upper position, said valve (6) being configured such that: during a filtering mode of the filter, when the flow of water exits through the outlet port (S), the valve (6) adopts its open position allowing water to flow through the central hole (61c) and the peripheral holes (61p); and during a cleaning mode of the filter, when water enters through the outlet port (S), the flow of water pushes the shutter (62) vertically upwards causing it to adopt its closed position, so that the water flows only through the central hole (61c), passes through the turbine (4) rotating the tube (5) fixed to its rotor, reaches the interior space of the tube (5), and is expelled under pressure in an external radial direction through the perforations (51 ), thus improving filter cleanliness.

2. System (1) according to claim 1, wherein the perforations (51) of the tube have the shape of an inclined slot.

3. System (1) according to any of the preceding claims, wherein the spring (63) comprises several spring-loaded screws.

4. System (1) according to any of the preceding claims, wherein the body (61) is in the form of an annular disc whose central opening forms the central hole (61c) and is provided with the peripheral holes (61 p).

5. System (1) according to claim 4, wherein the shutter (62) is in the form of an annular disc lacking holes except for its central opening.

6. System (1) according to claim 5, wherein an upper face of the shutter (62) comprises a rubber coating.

7. Ring filter comprising a cleaning improvement system (1) according to any of the preceding claims.

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