The present invention relates to a filtration net washing method and a filter for using that method. In the filtration process a gradual pollution of the filtration net with particles suspended in the filtered medium is inevitable, leading to clogging of the filter and reduction of the normal filtration ability. All particles bigger than net meshes stop on the net thus creating so called filter cake. Pressure difference between an inlet and outlet rises, and eventually the medium is not filtered. Therefore, it is extremely essential how to proceed with the polluted, clogged filter. In case of disposable filters there is a simple filter or its cartridge exchange for a new one. In turn, half- automatic filters are dismantled and washed by hand, or automatically by reverse rinsing. Automatically cleaned filters are expensive, and, what is more important, big and complex in their structure. In majority, these methods require switching off the filter from work, even temporary, and filters, which do not require switching off, have a complex and expensive structure. The purpose of the present invention is to eliminate the drawbacks of filter washing methods known so far by designing a new filtration net washing method, permitting to use a new simple construction in filter.

A filtration net washing method characterizes in that the medium passes through a filtration net, according to the filtration direction, and after cleaning it is directed to a clean medium outlet and partially compressed, preferably with a pump, which is preferably integrated with a filter, and then after the compression it is reversed to the inside of the filter preferably with a lengthened rotary mechanism, driven rotary with an electric motor and/or an integrated pump, not touching the filtration net, the said mechanism being hollow inside, which through at least one washing ending jets the medium on that net from inside to outside, the touch area of the medium stream with the filtration net is small and preferably is from 0,1 mm ² do 1 cm ² , the net washing medium pressure is higher than the filtration pressure in the filter, being up to several hundreds bars, preferably 3-20 bars, the rotary speed at washing medium application being from several rotations/min. up to 10000 rotations/min., preferably 3500 rotations/min., and the process of filtration net washing is conducted without switching off the filter. The lengthened rotary mechanism is a rotary shaft of a pump or of an electric motor. The medium for washing the net is applied to the inside of the hollow shaft in the center of that shaft or at the end of that shaft through an aperture leading to that hollow being in the pressure chamber, where the washing medium stream is applied rotatably, vibratorily or pulsatorily. The washing ending is small aperture, a jet nozzle, a nozzle with an aperture, a rotary nozzle or a rotor of an integrated pump, and the medium passes through that ending at an angle to the shaft rotation axis, and the size of the washing ending is preferably 0,5mm to 1 cm. In turn, the distance of the medium application is from several mm up to several cm or even greater in cases of huge applications. A filter for using the filtration net washing method, comprising elements with a dirty medium inlet, a clean medium outlet, a sewage outlet and a washing medium inlet, characterizes in that it has a lengthened rotary mechanism not touching a filtration net and hollow inside, driven by a power source, passing through a pressure chamber, a collecting chamber and a filtration chamber, arranged in different order, which mechanism through at least one washing ending jets the medium on that net from inside to outside, and the filtration net length is smaller than the filtration chamber length. The lengthened rotary mechanism is a rotary shaft of a medium compressing pump or of an electric motor, the rotary shaft on its length between the pressure chamber and the filtration chamber has a non-through axial hole and at least one washing ending being a small aperture, a jet nozzle or a nozzle with an aperture, through which aperture the medium passes at an angle to the shaft rotation axis, and the size of the washing ending is preferably 0,5mm to 1 cm. Preferably the filter elements are arranged successively as: the power source, the pressure chamber with a both-side sealing, the collecting chamber, the filtration chamber, or as: the pressure chamber with a one-side sealing, the power source, the collecting chamber, the filtration chamber, or as: the power source, the collecting chamber, the filtration chamber, the pressure chamber with a one-side sealing or as: the pressure chamber with a both-side sealing, the filtration chamber, the collecting chamber, the power source. Besides, the pressure chamber has a washing medium inlet, the collecting chamber has a clean medium outlet, and the filtration chamber has a dirty medium inlet and a sewage outlet.

One version of filter for using the filtration net washing method, comprising elements with a dirty medium inlet, a clean medium outlet, a sewage outlet and a washing medium inlet, characterizes in that it has a self-driven by water rejection force rotary mechanism, with both-side bearings and passing through a pressure chamber with a both-side sealing, a collecting chamber and a filtration chamber with a stationary filtration net having a length smaller than the length of that chamber, said filtration net being sealed in places of both-side fastening, where the rotary mechanism on its length between the pressure chamber and the filtration chamber has a non- through axial hole and at least one washing ending, the washing medium being compressed by an external pump. The rotary mechanism is a rotary shaft, whereas the washing ending is a small aperture, a jet nozzle or a nozzle with an aperture, through which aperture the medium passes at an angle to the shaft rotation axis, and the size of the washing ending is preferably 0,5mm to 1cm. The pressure chamber has a washing medium inlet, the collecting chamber has a clean medium outlet, and the filtration chamber has a dirty medium inlet and a sewage outlet.

Another version of filter for using the filtration net washing method, comprising elements with a dirty medium inlet, a clean medium outlet, a sewage outlet and a washing medium inlet, characterizes in that it has one chamber divided by a flat filtration net into a dirty medium chamber and a clean medium chamber, the filtration net has a both-side sealing, and the dirty medium chamber has an inlet of that medium and a sewage outlet, and the clean medium chamber has a clean medium outlet and inlets of at least one washing ending, a power source is an impulse pump, and washing ending is a small aperture, a jet nozzle or a nozzle with an aperture, through which aperture the medium passes at an angle to the shaft rotation axis, and the size of the washing ending is preferably 0,5mm to 1 cm.

Next version of filter for using the filtration net washing method, comprising elements with a dirty medium inlet, a clean medium outlet, a sewage outlet and a washing medium inlet, characterizes in that it has power sources with a shaft, connected with a filtration chamber, to which chamber the shaft enters, on the shaft there is a rotary filtration net, with bearings and sealed with a sealing, whereas in the filtration chamber casing there is at least one washing ending. The first power source is a pump, and the second one is an electric motor, the pump compresses the washing medium and rotates the filtration net, the washing ending is a small aperture, a jet nozzle or a nozzle with an aperture, through which aperture the medium passes at an angle to the shaft rotation axis, and the size of the washing ending is preferably 0,5mm to 1cm. The filtration chamber has a clean medium outlet and inlets of the washing endings applying the medium, as well as a dirty medium inlet and a sewage outlet.

Another version of filter for using the filtration net washing method, comprising elements with a dirty medium inlet, a clean medium outlet, a sewage outlet and a washing medium inlet, characterizes in that a power source drives at least one rotor of a pump, which pump compresses this medium, and the last rotor applies the washing medium preferably by washing endings or directly on a filtration net, where the filtration chamber with a dirty medium inlet and a sewage outlet comprises inside a collecting chamber with a clean medium outlet and the filtration net opposite the dirty medium inlet and the sewage outlet of the filtration chamber, and the pump is located inside the collecting chamber. The washing ending is a small aperture, a jet nozzle, a nozzle with an aperture or a rotary nozzle, through which ending the medium passes at an angle to the shaft rotation axis, and the size of the washing ending is preferably 0,5mm to 1 cm.

In embodiments of the filter according to the invention, the medium feeding through a rotary shaft hollow is through a hole leading to this hollow, the hole being located in the pressure chamber and at the same time in the center or at the end of the shaft.

The filtration nets are of different shapes, preferably of a cylinder or a flat circle, they are made of different materials, preferably of metal, plastic or ceramics, and the rotary mechanism can be made of different materials, preferably it can be made of metal or plastic.

The filtration net washing method and the filter for that method allow to clean the net during the filtration process, continuously or periodically. The filter cake is not produced or it is ripped off, the filtration net is not changed, there is an elimination of the filter service or washing its net by hand and since the cleaning takes place while filtration there is no need to stop the filtration process for cleaning the filtration net.

Washing of the net according to the invention is touchless, what does not cause its destructions, and filters for that method can work both in very high and very low temperatures, they are very efficient and of a very small size, they are simple in their structure, they are cheap and not too much problematic in use, they have very little parts thus causing their easy service, maintenance and control. Having a smaller size, the filters are more efficient, and besides, they can work in a fluid medium such as for example sweet water, sea water, sewage and industrial wastes, fuels, caustic and flammable substances, as well as in gaseous medium. The proposed filtration net washing method is suitable for nets with meshes of different size, even smaller than 0,01 microns.

The invention is shown by way of example in embodiments on drawings, not limiting the scope of protection, on which:

Fig. 1 shows the first embodiment of the filter for using the filtration net washing method according to the invention in the axial sectional view - a filter driven with an electric motor, with an external pump and a shaft fed in the center,

Fig. 2 shows another embodiment of the filter for using the filtration net washing method according to the invention in the axial sectional view - a filter driven with a pump integrated with it, the shaft being fed by a pump rotor, Fig. 3 shows another embodiment of the filter for using the filtration net washing method according to the invention in the axial sectional view - a self-driven filter, with a shaft fed in the center and with an external pump,

Fig. 4 shows another embodiment of the filter for using the filtration net washing method according to the invention in the axial sectional view - a filter without a shaft, with nozzles, preferably rotary ones and a pulsatory pump,

Fig. 5 shows another embodiment of the filter for using the filtration net washing method according to the invention in the axial sectional view - a filter driven with an integrated pump, with feeding from the top of a long shaft supported by a bearing,

Fig. 6 shows the elements of the filter presented on Fig. 5, Fig. 7 shows another embodiment of the filter for using the filtration net washing method according to the invention in the axial sectional view - a filter with a rotary net, the filter being driven with an integrated pump,

Fig. 8 shows another embodiment of the filter for using the filtration net washing method according to the invention in the axial sectional view - a filter integrated with a pump from the side of an electric motor,

Fig.9 shows another embodiment of the filter for using the filtration net washing method according to the invention in the axial sectional view - a compact filter driven with a pump built inside the construction of the filter, and Fig. 10 shows the elements of the filter presented on Fig. 9 in block diagram, and the medium motion in the filter is presented on the drawings by arrows.

Filtration net washing method according to the invention is that the medium passes through a filtration net 7 accordingly to the filtration direction, and after cleaning it is directed to a clean medium outlet 9 and partially compressed by a pump 2 and reversed to the inside of the filter with a lengthened rotary shaft 5 of the pump 2, the shaft being hollow inside. The medium for washing the net 7 is fed to the inside of the hollow shaft 5 in the center of that shaft, and according to the other embodiment, the medium is fed to the inside of the shaft 5 at its end. The shaft 5 jets the medium rotatably on the net 7 from inside to outside. In other embodiments, there are possible other methods of feeding the medium to the inside of the filter, for example by other rotary mechanism not touching the filtration net 7. The medium stream is fed rotatably, in other embodiments vibratorily or pulsatorily. With a washing ending 2 the cleaned medium ejects and washes the net 7 from the clean side so that after passing the net 7 against the filtration direction to the dirty side it removes a filtration cake which flows further with the medium and goes to the sewage. The washing ending 12 is a small aperture, in another embodiment it is a jet ending (nozzle) and in another embodiment - a special washing nozzle with an aperture through which the medium passes at an angle to the shaft 5 rotation axis. Locating of the medium outlet axis at an angle to the shaft 5 rotation axis results in the medium stream sweeping the net accordingly to the shaft 5 rotations. In another embodiment the washing ending 2 is a rotatable nozzle or a rotor of an integrated pump 2. The medium application distance ranges from several mm to several cm or even greater for huge applications.

The shaft 5 rotates around its own axis and washes the filtration net 7 ejecting the medium rotatably, at high speed changing the place of washing, causing that the filtration is not interrupted for the washing time, as in the place where the stream washes the medium does not flow in the filtration direction due to the pressure difference, and after passing the place of contact of the stream with the filtration net 7 it returns. The contact area of the stream with the filtration net 7 is 0,1mm ² , in other embodiments it rises gradually to 1 cm ² .

The whole filter is fixed on the said shaft 5 and with this shaft the washing medium flows. In other embodiment, a pump 2 can be outside a shaft 5 feeding the medium. The shaft 5 rotates with the pump 2 rotation speed, which pump is used for compressing the medium, preferably at the speed of 3000 rotations/min. In another embodiment the rotation speed is 3500 rotations/min. The rotation speed of the shaft 5, and because of that the influence time of the medium stream on the filtration net 7, and the time of break for another filtration and time for another washing operation can be regulated from several rotations/min. to 10000 rotations/min. depending on the application and speed (depending on the medium and pollution with suspended particles). In another embodiment, the shaft 5 is not located on the pump 2, but it is located on an electric motor 2a of a changing speed, controlled with an inverter, and there is a separate pump for feeding the medium for net washing. The pressure of the medium for net washing exceeds the filtration pressure in the filter so as to overcome the distance between the shaft 5 and the filtration net 7. In one embodiment, pressure of washing is 10 bars and filtration pressure is 1 bar. In another embodiment there was used washing pressure of 2 bars and filtration pressure of 1 bar. In another embodiment, there was used washing pressure of 5 bars and filtration pressure of 1 bar. In other embodiments washing pressure was risen gradually to several hundreds bars.

A filter for using the filtration net washing method according to the invention, shown on Fig. 1 , comprises a pressure chamber 1, connected from one side with an electric motor 2a and an external pump 2 (not shown on the picture), with a separate bearing, from the second side with a collecting chamber 3, with a both-side mechanic sealing 4 of the pressure chamber 1, through which sealing a rotary shaft 5 passes up to a filtration chamber 6 with a filtration net 7. The filtration chamber 6 has a stationary filtration net 7 in a shape of a cylinder of a length smaller than the length of that chamber, sealed in the place of fixing. The pressure chamber 1 has a washing (filtrated) medium inlet 8, the collecting chamber 3 has a clean medium outlet 9, and the filtration chamber 6 has a dirty medium inlet 0 and a sewage outlet 11 The rotary shaft 5 on its length between the pressure chamber 1 and the filtration chamber 6 has a non-through axial hole 5a for passing the medium and at least one nozzle 2 for applying the washing medium. The dirty medium enters at 2 bar pressure, and the washing medium is fed at 10 bar pressure from the inside of the rotary shaft 5 through the nozzles 12 on the filtration net 7 removing contaminations gathered on that net. The shaft speed is 3500 rotations/min.

In another embodiment shown on Fig. 2, a filter for using the filtration net washing method according to the invention comprises a pump 2 connected from one side through an electric motor 2a with a pressure chamber 1 having a one-side sealing 4, and from the other side with a collecting chamber 3, though which elements a rotary shaft 5 passes up to a filtration chamber 6 with a filtration net 7. The filtration chamber 6 has a stationary filtration net 7 in the shape of a cylinder of a length smaller than the length of that chamber, sealed in the place of fixing. The pressure chamber 1 has a washing (filtrated) medium inlet 8, the collecting chamber 3 has a clean medium outlet 9, and the filtration chamber 6 has a dirty medium inlet 10 and a sewage outlet 11 The rotary shaft 5 on its length between the pressure chamber 1 and the filtration chamber 6_ has a non-through axial hole 5a for passing the medium and at least one nozzle 12 for applying the washing medium. The dirty medium enters at 1-2 bar pressure, and the washing medium is fed at 10 bar pressure from the inside of the rotary shaft 5 through the nozzles 12 on the filtration net 7 removing contaminations gathered on that net. The shaft and electric motor speed is 3500 rotations/min.

In another embodiment shown on Fig. 3, a filter for using the filtration net washing method according to the invention comprises a self-driven shaft 5 with a water ejection force, with both-side bearings and passing through a pressure chamber 1 with a both-side sealing 4, a collecting chamber 3 and a filtration chamber 6 with a filtration net 7. The filtration chamber 6 has a stationary filtration being sealed in places of both-side fastening. The pressure chamber 1 has a washing (filtrated) medium inlet 8, the collecting chamber 3 has a clean medium outlet 9, and the filtration chamber 6 has a dirty medium inlet 10 and a sewage outlet H. The rotary shaft 5 on its length between the pressure chamber 1 and the filtration chamber 6 has a non-through axial hole 5a for passing the medium and at least one nozzle 12 for applying the washing medium. The dirty medium enters at 1- 2 bar pressure, and the washing medium is compressed by an external pump (not shown on the picture) and fed at 10 bar pressure from the inside of the rotary shaft 5 through the nozzles 12 on the filtration net 7 removing contaminations gathered on that net.

In another embodiment shown on Fig. 4, a filter for using the filtration net washing method according to the invention comprises one chamber divided by a flat filtration net 7 into a dirty medium chamber 7a and a clean medium chamber 7b- The filtration net 7 is sealed on both sides with orings. The dirty medium chamber 7a has an inlet 0 of that medium and a sewage outlet H, whereas the clean medium chamber 7b has a clean medium outlet 9 and inlets of nozzles 12, preferably rotary nozzles, through which the washing medium is fed pulsatorily at 10 bar pressure by an impulse pump, not shown on the picture.

In another embodiment shown on Figs. 5 and 6, a filter for using the filtration net washing method according to the invention comprises a pump 2 with an electric motor 2a and a rotor, in which a rotary shaft 5 is bearinged, the shaft passing through bearings and a sealing, a collecting chamber 3, a filtration chamber 6, bearings and a sealing up to a pressure chamber 1 with a one- side sealing 4. The pressure chamber 1 has a washing (filtrated) medium inlet 8, the collecting chamber 3 has a clean medium outlet 9, and the filtration chamber 6 has a dirty medium inlet 10 and a sewage outlet 1J_. The filtration chamber 6_has a stationary filtration net 7 of a cylindrical shape, sealed on the both sides. The rotary shaft 5 on its length between the pressure chamber 1 and the filtration chamber 6 has a non-through axial hole 5a for passing the medium and at least one nozzle 12 for applying the washing medium. The dirty medium enters at 2 bar pressure, and the washing medium is fed at 10 bar pressure from the inside of the rotary shaft 5 through the nozzles 12 on the filtration net 7, removing contaminations gathered on that net.

In another embodiment shown on Fig. 7, a filter for using the filtration net washing method according to the invention comprises a pump 2 with a shaft 5, the pump driven with an electric motor 2a with a rotor. The pump 2 is connected with a filtration chamber 6, to which chamber the shaft 5 enters, on said shaft there is a rotary filtration net 7, with bearings and sealed with a sealing 4. The pump 2 compresses the washing medium and rotates the filtration net 7. The filtration chamber 6 has a clean medium outlet 9 and inlets of the nozzles 12 applying the medium, as well as a dirty medium inlet 10 and a sewage outlet . The dirty medium enters at 2 bar pressure, and the washing medium is fed at 10 bar pressure through the nozzles 12, which apertures are in the filtration chamber 6 casing. In another embodiment shown on Fig. 8, a filter for using the filtration net washing method according to the invention comprises a pressure chamber 1, a filtration chamber 6 and a collecting chamber 3 connected in a mirror reflection way while comparing to the connection of these elements on Fig. 5 and 6, and the collecting chamber 3 is connected to an electric motor 2a and a pump 2 supplying a rotary shaft 5 passing through the filter elements, the shaft having both-side bearings and a sealing. The pressure chamber 1 has a washing (filtrated) medium inlet 8, the collecting chamber 3 has a clean medium outlet 9, and the filtration chamber 6 has a dirty medium inlet 10 and a sewage outlet H. The filtration chamber 6 has a stationary filtration net 7 of a cylindrical shape, sealed on the both sides. The rotary shaft 5 on its length between the pressure chamber 1 and the filtration chamber 6 has a non-through axial hole 5a for passing the medium and at least one nozzle 12 for applying the washing medium. The dirty medium enters at 2 bar pressure, and the washing medium is fed at 10 bar pressure from the inside of the rotary shaft 5 through the nozzles 12 on the filtration net 7 removing contaminations gathered on that net.

In another embodiment shown on Figs. 9 and 10, a filter does not comprise a rotary shaft 5 nor a pressure chamber 1, since its electric motor 2a drives at least one rotor of a pump 2, the pump compressing the medium, and the last rotor applies the washing medium through nozzles 12 on a filtration net 7, where a filtration chamber 6 with a dirty medium inlet 10 and a sewage outlet H comprises inside a collecting chamber 3 with a clean medium outlet 9 and the filtration net opposite the dirty medium inlet 10 and the sewage outlet H of the filtration chamber 6. The pump 2 is located inside the collecting chamber 3. In another embodiment, not shown on the picture, the rotor applies the medium directly on the filtration net 7.

In other filter embodiment, not shown on the picture, a rotary shaft 5 and nozzles 12 applying the medium at an angle, were replaced by a rotary nozzle.

Feeding the medium by a hollow 5a of the rotary shaft 5 is through an aperture leading to that hollow, the aperture being in the pressure chamber and at the same time in the center or at the end of the shaft 5.

In filter embodiments, a washing ending 12 is a small aperture, a jet nozzle, a nozzle with an aperture, a rotary nozzle or a rotor of a pump, through that ending the medium passes at an angle, and the size of the washing ending 1_2 is preferably 0,5mm to 1 cm. The filtration nets 7 for using the method according to the invention in the preceding embodiments are of different shapes, preferably cylindrical or a flat circle, and are made of different materials, preferably metal, plastic or ceramics. In turn, the rotary shaft 5 can be made of different materials, preferably metal or plastic.

The proposed filtration net washing method is suitable for a cross filtration "cross-flow" and "dead-end" filtration.