TITLE

FLOATING FILTERING PARTICLE FILTER FOR FLUIDS WITH CLEANING DEVICE AND ANTI-REFLUX DIFFUSER

DESCRIPTION The present patent relates to filters for fluids and in particular concerns filters for fluids with floating particles, biological filters and clarifiers.

Filters for fluids, also called clarifiers, are known, the filtering element of which consists of a mass of floating particles.

Said floating particle filters comprise a reservoir containing a filtering mass of floating particles, typically pellets or granules of plastic material.

The inlet fitting of the fluid to be filtered is positioned in the inner median or lower area of the reservoir and is provided with a diffuser, while the filtered fluid draw-off fitting is located on the top of said reservoir. A mesh or other open-work element is provided below said filtered fluid draw-off fitting suitable for retaining the floating filtering particles while permitting passage of the fluid.

The dirty fluid enters the reservoir at the bottom, filling it.

The mass of filtering particles floats and is always positioned at the top of the reservoir against the mesh or the particle retaining element.

The diffuser positioned on the inlet fitting prevents clogging of said inlet and prevents outflow of the filtering particles towards the basin or tank to be filtered.

The fluid crosses the mass of filtering particles which retain the bodies suspended in the fluid.

The fluid that has crossed the mass of filtering particles, now without any suspended bodies, flows out through the reservoir outlet fitting. The suspended bodies and the dirt in general of larger dimensions retained by the floating filtering particles remain among said particles or sediment on the bottom of the reservoir.

An outlet fitting with valve on the bottom of the reservoir permits evacuation of said bodies and dirt deposited and sedimented on the bottom of the reservoir.

The suspended bodies and the smaller lighter impurities are retained by the floating filtering particles and remain trapped between said filtering particles or adhere to the surface of said filtering particles increasing the efficiency of the filtering mass.

Various operations are performed to recover part of the filtering efficiency of the mass of floating particles.

The material deposited on the bottom of the reservoir is discharged by opening the corresponding discharge valve located in the lower part of the reservoir of the filter while it is operating.

The filtering mass is cleaned by means of a pressurised jet of air directed into the mass of filtering particles.

Said jet of air agitates and moves the particles of the filtering mass in the fluid to be filtered so that they release the dirt retained among them adhering to the surface of each particle.

Said solution with jet of air, although more efficient than backwashing, has a number of drawbacks.

The jet of air is generated by an electric pump or fan not designed for use in a damp environment. Consequently any excess pressure of the fluid to be filtered and/or reflux of it inside the air blowing ducts can reach said fans, flooding them and damaging them. Switch-on of the fan when wet causes short-circuiting and damage; the fan therefore has to be replaced, with consequent machine down time.

Furthermore said short circuit introduces electrical current into the fluid and consequently into the basin or tank, killing the fish or other species farmed in the basin or tank, or even endangering people's lives.

The use of non-return valves does not eliminate the problem as the reflux fluid is viscous and fouls said non-return valves, limiting and/or annulling in certain cases

the operation thereof.

It should also be remembered that all the couplings and connection ducts between the fan and the blowers inside the filter reservoir require sealing so that both the pressure generated by the fan and the pressure of the filtering circulation pump do not cause outflow of the fluid.

Another operation performed to restore the filtering efficiency of the particle mass is backwashing, i.e. the flow direction of the liquid is inverted: the fluid inside the reservoir is extracted from the lower inlet fitting and re-introduced into the reservoir via the upper outlet fitting. Said backwashing permits cleaning of the ducts, the inlet diffuser and the mass of filtering particles.

Furthermore backwashing is performed using the same pump as the one used for the filtering cycle and 4 or 6- way valves which invert the flow of the fluid. To invert the flow of the liquid in the filter, various ducts and various valves or specific multi-way valves are required which are very costly and can be ^' subject to malfunctioning which affects operation of the filter.

The current filters require manual intervention of the operator who must rotate and/or correctly position the multi-way valves. Said operation involves the risk of incorrect positioning of the 4 or 5-way valves, possible re-introduction of the dirt already filtered into the basin or tank of fluid to be filtered and possible damage to the equipment.

Automation of the positioning of the multi-way valve is possible using costly electromechanical actuators which must be controlled by an appropriate control unit. In order to be performed correctly and effectively, backwashing therefore requires a complex system of valves and ducts and/or costly and powerful pumps, also bidirectional, which require periodical maintenance and are subject to frequent malfunctioning.

The known inlet ducts are provided with an inlet diffuser, positioned at the end and having the function of uniformly diffusing the incoming fluid.

The known diffusers are provided with a dense grille, to prevent the floating particles of the filtering mass from leaking out during backwashing or when the pump is at a standstill and consequently retain the suspended bodies of larger dimensions, thus providing a coarse filter.

The known inlet diffusers have numerous drawbacks, however.

Firstly the impurities retained by the grille of the inlet diffusers accumulate on it, progressively reducing the working surface for passage of the flow of fluid. This consequently reduces the pump flow rate, making it necessary to use high power pumps to ensure a given flow of water.

For this reason pumps of at least 1200W are usually used.

Clogging of the grille, furthermore, means that less liquid flows into the tank, reducing the filtering power of the clarifier, which therefore has to work longer, with the same liquid flow rate at the outlet.

In the long run, furthermore, maintenance will be necessary to clean or even replace said grille or said inlet diffuser.

To remedy all the above drawbacks a new floating filtering particle filter for fluids with device for cleaning and washing the floating particles has been designed and produced.

A new type of inlet diffuser for clarifiers and biological filters, with anti-reflux floater, has also been studied.

The aim of the new filter is to efficiently perform rinsing of the floating filtering particles without dangers for the operator and/or for the flora and fauna of the basin or tank of liquid to be filtered.

A further aim of the new filter is to perform complete rinsing of the mass of filtering particles without affecting in any way the other remaining parts of the filtering plant.

A further aim of the new filter is to perform final rinsing of the filtering particles using the circulation pump and related special or additional valves.

A further aim of the new filter is to prevent the filtered dirt from returning to the basin or tank of the fluid to be filtered. A further aim of the new filter is to prevent the dirt removed by the filtering particles, more concentrated than the dirt normally present in the fluid to be filtered, returning and depositing in the pump and in the circulation valves.

A further aim of the new filter is to permit washing of the floating filtering particles also when the circulation pump is at a standstill, for example during maintenance. A further aim of the new filter is to use simple parts and reduce the number of parts that are complex and costly for its production.

A further aim of the present invention is to reduce loss of flow of the fluid intake pump.

A further aim of the present invention is to use pumps with a low head and therefore lower power with the same fluid intake flow rate, with consequent energy saving.

A further aim of the present invention is to create, at the inlet, a uniform flow of fluid, reducing the phenomena of turbulence.

A further aim of the present invention is to prevent reflux of the fluid and floating filtering particles into the inlet duct, during backwashing and/or when the intake pump is at rest.

These and further aims, direct and complementary, are achieved by the new floating filtering particle filter for fluids with device for cleaning the floating particles comprising a reservoir, a mass of floating filtering particles, at least one further pump dedicated to washing the floating filtering particles with related draw-off and delivery ducts, and if necessary provided with a new inlet diffuser for clarifϊers and biological filters, with anti-reflux floater.

The reservoir can have any shape, with the bottom tapered in order to convey the

sediments to one single area.

Said reservoir has at least one lower fitting with valve for discharging the sediments, at least one upper fitting for outlet of the filtered fluid, at least one upper or lateral fitting with duct and diffuser for inlet of the fluid to be filtered. In the upper area of the reservoir, near the fluid outlet fitting, there is a mesh, a membrane or a perforated metal sheet suitable for retaining the floating filtering particles and permitting passage of the fluid.

The mass of floating filtering particles is housed inside the reservoir. Said mass of floating filtering particles can consist of small particles, generally spherical, made of any suitable material, for example suitable plastic material.

A fluid pump is scheduled, specifically dedicated to washing the floating filtering particles, suitable for positioning inside or outside the reservoir. Said fluid pump is preferably of the immersion type, i.e. with the possibility of operating immersed in a fluid without dispersions of current in the fluid. Said dedicated pump is connected to a draw-off duct and to one or more delivery ducts with sprayers or nozzles at the end.

The draw-off duct of the dedicated pump is positioned in the median or lower area of the reservoir so as to withdraw the fluid contained in the reservoir below the mass of filtering particles. The delivery ducts have nozzles or sprayers positioned near or, preferably, corresponding to the mass of filtering particles.

In particular said nozzles or sprayers are located between the centre of the reservoir and its side walls and are facing upwards.

To perform rinsing of the filtering particles, operation of the circulation pump is preferably interrupted and the dedicated pump of the new filter is operated.

The dedicated pump of the new filter takes part of the fluid from the reservoir and sends it under pressure inside the reservoir itself to move the floating filtering

particles.

Said jet of fluid agitates and separates the various floating filtering particles so as to release the bodies retained by the mass of particles and remove the dirt that has adhered to said filtering particles. Filter for fluids with floating filtering particles, comprising a reservoir with at least one lower outlet fitting, at least one upper fitting for outlet of the filtered fluid with mesh or retaining membrane, at least one fitting for inlet of the fluid to be filtered, a mass of floating filtering particles housed inside said reservoir, one or more dedicated pumps for washing the filtering particles, provided with draw-off and delivery ducts, suitable for withdrawing part of the fluid inside the reservoir and sending it under pressure near to said floating filtering particles.

The new inlet diffuser consists in its main parts of a wide-mesh grille containing a floating element, with substantially spherical shape.

Said inlet diffuser is applied at the end of the fluid inlet duct. For said purpose, said wide-mesh grille of the new diffuser comprises a part shaped so that it can be fixed to said inlet duct.

For example, the new invention comprises a sleeve suitable for fixing on said inlet duct, provided with wide-mesh grille which creates a closed space, with a substantially spherical, parallelepiped, tapered, etc. shape, containing said floating element.

The meshes of said grille have dimensions such as to retain said floating element but not the impurities contained in the fluid to be clarified, which is filtered by the floating filtering particles.

Said spherical element has dimensions such as to occlude the fitting of the inlet duct, completely or in any case sufficiently to prevent outflow of the filtering particles.

Said wide-mesh grille therefore prevents the known clogging phenomena, and loss of flow of the pump is thus significantly reduced.

This permits the use of less powerful pumps, with obvious important savings in consumption. In fact 250W pumps can be used, i.e. normal garden pumps.

Said saving is of great interest, above all because the known clarifiers are kept running non-stop round the clock and seven days a week. The use of less powerful pumps reduces the water inlet speed but, since the working surface for passage of the fluid is larger than in the known diffusers, the water flows out, at the same flow rate, more uniformly, i.e. turbulence is reduced.

By installing the new inlet diffuser, the fluid is taken from the outside and introduced into the reservoir via said duct and said new inlet diffuser. The outlet duct takes the fluid from inside the reservoir, so that said fluid, as it crosses the filtering mass of floating particles, is cleaned of the impurities and suspended bodies.

In this way the fluid is clarified and can be discharged to the outside, into the receiver basin. To perform cleaning of the filtering mass, the known techniques can be applied; to carry out backwashing, the cycle is inverted and the fluid inside the reservoir is not extracted via the inlet duct but via the outlet duct located, as is known, near the lower part of the reservoir.

During backwashing, the intake pump stops, the floating element is pushed upwards by the fluid, occluding the fitting and substantially preventing said intake duct from drawing off the fluid and, above all, the floating filtering particles from inside the reservoir.

The backwashing fluid, loaded with the impurities collected from the bottom of the reservoir and coming from cleaning of the filtering mass, is then sent directly to the disposal facility via the outlet duct, considerably simplifying the system of valves and ducts.

In particular, the new inlet diffuser with anti-reflux floater comprises a base and a

perforated cover for insertion of the inlet duct fitting, wherein said base and said cover are integral with one or more substantially vertical partitions suitable for creating a compartment for movement of said floating element.

Preferably said partitions have a curved shape with helical form or, alternatively, they can have, for example, a generically linear shape and be arranged radially.

The attached drawings show, as a non-limiting example, a practical embodiment of the invention.

Figure 1 illustrates a vertical section of an embodiment version of the new filter comprising a reservoir (S) containing a mass of floating filtering particles (F) and a dedicated pump (P) with related draw-off (Pa) and delivery (Pm) ducts for cleaning the filtering particles (F).

In this example the filter reservoir (S) has a generically cylindrical shape with the upper part or roof (Ss) and the lower part or bottom (Si) dome-shaped.

The dome-shaped bottom (Si) features a fitting for discharge (So) of the sediments deposited. Said outlet fitting (So) is provided with related valve (Sv).

The dome-shaped roof (Ss) features a valve (M) having ducts for inlet (I) and outlet

(U) respectively of the fluid to be filtered and the fluid filtered.

In particular the incoming fluid crosses said valve (M) and passes through a central vertical duct (Ma) provided at the bottom with diffuser (Md) for accessing the median/lower part of the reservoir (S).

Below the valve (M) there is a grate or grille (Mg) through which the filtered fluid flows out.

Said grate or grille (Mg) retains the filtering floating particles (F) and permits passage of the fluid. Said valve (M) can be of the multi-way type and consequently provided with lever or knob (Ml) for flow diversion/inversion.

The mass of floating filtering particles (F) is housed inside the reservoir (S).

Said floating filtering particles (F) can be made of any suitable material, preferably plastic.

Said mass of filtering particles (F) ₅ due to its floating property, is pushed and piled up by the fluid below the grille or grate (Mg) of the valve (M). In this example the dedicated pump (P) is applied to the wall of the reservoir (S).

The dedicated pump (P) consists preferably of a pump, the draw-off duct (Pa) of which draws from below the mass of floating filtering particles (F), in the lower area of the reservoir but at a distance from the bottom and from the area where the sedimented dirt is deposited. The delivery duct (Pm) of the dedicated pump (P) preferably splits into several ducts

(Pm) terminating in nozzles or sprayers (Ps) near the area normally occupied by the mass of floating filtering particles (F) and facing upwards.

It is possible to provide for the dedicated pump (P) to be housed inside the reservoir

(S), as can be seen in the example of figure 2, and connected or hooked to the vertical duct (Ma) for intake of the fluid into the reservoir (S).

It is possible to provide for the use of several dedicated pumps (P) each with one or more delivery ducts (Pm). Said pumps can be housed outside and/or inside the filter reservoir (S).

During normal operation of the filter, the fluid is taken into the reservoir (S) via the inlet duct (I), the valve (M), the central vertical duct (Ma) and the related diffuser

(Md).

The fluid passes through the mass of floating filtering particles (F) and finally flows out through the grate or grille (Mg) of the valve (M) and the related outlet duct (U).

During said normal, operation of the filter the dedicated pump (P) remains switched off.

The dirt transported by the fluid falls onto the bottom of the reservoir (S) of the new filter, while the lighter dirt with smaller dimensions in suspension in the fluid is

retained by the mass of filtering particles.

When the mass of floating filtering particles (F) is saturated with dirt, the filtering circuit is stopped, or alternatively the fluid to be filtered is conveyed towards another filter. The dirt already sedimented on the bottom (Si) of the reservoir (S) can already be discharged, together with a small part of fluid, via the outlet fitting (So).

To rinse the mass of floating filtering particles (F), the dedicated pump (P) is operated.

Said dedicated pump (P) takes part of the fluid from inside the reservoir (S), from an area below the mass of filtering particles (F), and blows it under pressure into said mass of filtering particles (F).

Said jet of fluid agitates the various filtering particles (F), generating a circulation that causes said particles (F) to rise towards the roof (Ss), fall back down the outer wall of the reservoir (S) and resume the cycle. Said agitation of the filtering particles (F) moves them away from one another so that the dirt retained between said filtering particles (F) drops and deposits on the bottom

(Si) of the reservoir (S).

In addition to this, said flow of fluid under pressure permits removal of the dirt that has adhered to the filtering particles (F). Said dedicated pump (P) is operated for a pre-set time, in the order of a few minutes.

After the dedicated pump (P) has stopped, the dirt removed from the filtering particles (F), which has deposited on the bottom (Si) of the reservoir (S), can be discharged via said outlet fitting (So).

The new floating filtering particle filter for fluids with device for rinsing the floating particles constituted as described above has considerable advantages.

The new filter is not affected by reflux or overpressure of the fluid towards the dedicated pump (P).

The new filter does not require non-return valves.

The new filter efficiently rinses the whole mass of filtering particles (F) without using the circulation pump and special or additional valves. This means that it is possible to continue the filtering function using two or more alternative filters in parallel: during maintenance and cleaning of a filter another filter is used for the normal filtering function.

The new filter permits rinsing of the filtering particles without increasing or reducing the pressure of the fluid inside or outside the filter.

The new filter can perform cleaning of the filtering particles (F) without requiring intervention of the pump and valves used in the normal filtering cycle. In this way the dirt accumulated among and on the filtering particles (F) ₃ more concentrated than the dirt normally present in the fluid to be filtered, does not affect, foul or deposit in the circulation pump, in the ducts and in the valves used for the normal filtering cycle. The new filter prevents the dirt removed from the filtering particles, more concentrated than the dirt normally present in the fluid to be filtered, from returning and depositing in the pump and in the circulation valves.

The new filter permits washing of the floating filtering particles (F) also with the circulation pump at a standstill, for example during maintenance. With respect to the known technique, the new solution allows backwashing to be performed in total safety.

The new filter permits automatic management, with simple electrical switches.

Figure 3 shows the new invention, while figure 3a-a shows a horizontal section of the new invention. Figure 4 shows the new invention with anti-reflux floater positioned to occlude the intake duct.

The new intake diffuser (Md) is connected and fixed to the fitting (Cl) of the intake

duct (Ma).

Said intake diffuser (Md) comprises a base (B), substantially flat, and an upper cover

(T), provided with aperture (Tl) for insertion of the fitting (Cl) of the intake duct

(Ma). Said base (B) and said upper cover (T) are integral with one or more partitions (V) curved and substantially vertical, arranged square to said base (B).

In particular said partitions (V) are arranged so as to leave the space necessary for positioning of a floating element (G) of substantially spherical shape.

Said spherical floating element (G) has a diameter greater than the diameter of the aperture (Tl) obtained in said cover (T), i.e. it has a diameter sufficient to occlude the fitting (Cl) of the intake duct (Ma), completely or in any case sufficiently to prevent outflow of the filtering particles.

The floating element (G) is therefore constrained to move in a space that is substantially cylindrical-shaped, defined laterally by said partitions (V), at the bottom by said base (B) and at the top by said cover (T).

Said partitions (V) are furthermore positioned so as not to create a closed cylindrical surface but leaving one or more side apertures (A), of dimensions such as to prevent passage of the floating element (G) while permitting passage of the impurities contained in the fluid to be clarified. In particular said partitions (V) can be positioned, as shown in figure la-a, with a substantially helical arrangement, i.e. with one edge (L) facing towards the centre of the base (B) and the other facing outwards, so that the flow of fluid to be clarified is taken in with a circular or vortex-like movement.

Said edge (L) is fine in order to create a blade suitable for removing any impurities that may adhere to the surface of the floating element (G).

During intake of the fluid to be clarified inside the filter reservoir, the flow of incoming fluid tends to push said floating element (G) towards the base (B), thus

keeping the fitting (Cl) of the intake duct (Ma) open.

When the intake pump is switched off, for example to perform backwashing, the thrust of the fluid causes the floating element (G) to rise to the top; said element, constrained at the side by said partitions (V) and at the top by the shape of the cover (T), occludes the aperture (Tl) and therefore the fitting (Cl) of the intake duct (Ma). For said purpose, said cover (T) has a tapered shape, for example, in order to compel the floating element (G) to locate in the correct position corresponding to the aperture (Tl).

Therefore with reference to the preceding description and the accompanying drawings the following claims are made.