The object of the invention relates to filtering equipment for the cleaning of water-based liquids with diatomaceous earth microfiltration, which contains a filter body suitable for accommodating and supporting a microfiltration layer, a base body having a receipt space and a housing suitable for accommodating the base body and the filter body, the filter body has a feed aperture located on the input side of the microfiltration layer and connected to the microfiltration layer so as to permit the flow of liquid, which is bordered by the internal covering surface of the filter body and is suitable for receiving the water-based liquid to be filtered, while the base body has at least one outlet passage serving for discharging the filtered water-based liquid, the internal delimiting surface of the base body and the external surface of the filter body are separated by a gap, and in the gap there is a discharge space part serving for transporting the filtered water-based liquid, the feed aperture of the filter body is connected to an intake passage suitable for transporting the liquid to be filtered into the feed aperture, while the intake passage is connected to a supply pipe, the equipment has at least one pressure sensor body connected to the supply pipe and/or to the intake passage and/or to the feed aperture, where the pressure sensor body has a connection with a control unit suitable for transmitting information, and the control unit is connected to a regulation body that influences the introduction of the water-based liquid to be filtered into the intake passage.

The object of the invention also relates to a method for the cleaning of water-based liquids with diatomaceous earth micro-filtration, during which a liquid containing diatomaceous earth is made to flow through the filter body of the filtering equipment from the direction corresponding to the flow direction of the water-based liquid to be filtered, and a microfiltration layer is created on this surface of the filter body, following this the water-based liquid to be filtered is passed through the created microfiltration layer, and the filtered water-based liquid is created in this way.

Water-based liquids are used in numerous places for industrial and private purposes. During use these water-based substances become contaminated in various ways. However, for reasons of environmental protection, contaminated water-based substances must be cleaned before they are returned to the water catchment.

Numerous examples of equipment and methods have been developed for the cleaning and filtering of such contaminated water-based substances. One possible form of cleaning is so-called diatomaceous earth filtration. The essence of diatomaceous earth filtration is that the contaminated water-based liquid is passed through a filtration layer consisting of a given composition of diatomaceous earth and cellulose. The pore size and so the effectiveness of the filtration may be regulated by mixing the diatomaceous earth and the cellulose at the appropriate ratio.

Patent specification registration number HU 215.752 discloses a diatomaceous earth- based filter plate that may be used, for example, for disinfecting water and a method for the production of the filter plate. While publication document base number HU P0800128 presents a device for the filtration of oily contaminants in which diatomaceous earth is used as a component of the filtration layer.

A significant disadvantage of these solutions is that they only use filtration bodies of a given composition, which may not be reused after use. A further disadvantage is that a filtration body of a given composition is only suitable for treating certain substances, therefore in the case of various materials various different pre-manufactured filtration bodies have to be used, which makes wide-ranging use difficult and also increases the cost of the use of the equipment.

A general deficiency of the known solutions is also that as a result of the origin of the liquid to be cleaned it is not always possible to use a filtration layer consisting of a mixture of the usual proportions of diatomaceous earth and cellulose in order to perform microfiltration.

Another deficiency of the known solutions is that in many cases the water-based substance to be cleaned cannot be cleaned with a filtration layer made of diatomaceous earth, as filtration resistance cannot be created on the filter surface, it ruptures and unfiltered liquid becomes partly mixed again with the filtered liquid. The objective of the solution according to the invention was to create equipment that makes it possible to improve the cleaning efficiency of microfiltration of contaminated water-based liquids irrespective of their origin so that a given amount of contaminated water-based liquid to be cleaned can be more effectively cleaned, and through which the specific cleaning costs and the treatment time required for the cleaning can be reduced.

The recognition that led to the solution according to the invention was that if the water- based liquid to be cleaned is filtered in an imconventional way not with a pre-set filter layer combination, instead, with consideration to the nature of the contaminated water- based liquid, the conventionally used diatomaceous earth is mixed in a novel way with pearlite, activated carbon, and optionally broken glass, and a filtration surface is created from the material mixed in this way, then a mixture may be created that corresponds to the composition of the contaminated water-based liquid that is intended to be cleaned, and so the cleaning efficiency may be increased, and the specific cleaning costs and the treatment time required for the cleaning can be reduced, and so the task may be solved.

The idea behind the invention also involved that if the filtration resistance is monitored in a suitable way during the filtration process, and in an unconventional way the filtration process is interrupted before a given value is reached, and the saturated microfiltration layer is removed from the filtration space in a novel way, and a new filtration layer is established, that is intermitted filtration is performed by establishing an optimal filtration layer on site, then the rupturing of the filtration layer can be avoided, enabling the further improvement of the efficiency of the filtration process, and the task may be more reliably solved.

In accordance with the set objective filtering equipment according to the invention for the cleaning of water-based liquids with diatomaceous earth micro -filtration, - which contains a filter body suitable for accommodating and supporting a microfiltration layer, a base body having a receipt space and a housing suitable for accommodating the base body and the filter body, the filter body has a feed aperture located on the input side of the microfiltration layer and connected to the microfiltration layer so as to permit the flow of liquid, which is bordered by the internal covering surface of the filter body and is suitable for receiving the water-based liquid to be filtered, while the base body has at least one outlet passage serving for discharging the filtered water-based liquid, the internal delimiting surface of the base body and the external surface of the filter body are separated by a gap, and in the gap there is a discharge space part serving for transporting the filtered water-based liquid, the feed aperture of the filter body is connected to an intake passage suitable for transporting the liquid to be filtered into the feed aperture, while the intake passage is connected to a supply pipe, the equipment has at least one pressure sensor body connected to the supply pipe and/or to the intake passage and/or to the feed aperture, where the pressure sensor body has a connection with a control unit suitable for transmitting information, and the control unit is connected to a regulation body that influences the introduction of the water-based liquid to be filtered into the intake passage, - is set up is such a way that the microfiltration layer of the filter body consists of a mixture of solid grains containing 50-95% diatomaceous earth and 5-50% cellulose and 5-50% pearlite and/or 5-50% zeolite and/or 5-50% activated carbon and/or 1-5% Si0 ₂ with respect to total solids.

A further feature of the filtering equipment according to the invention may be that the filter body has filter passages that have a strictly monotonously increasing cross-section from the direction of the internal covering surface delimiting the feed aperture towards the direction of the external covering surface of the filter body, and the microfiltration layer is at least partially established in the filter passages.

In the case of a possible embodiment of the filter equipment, at least a part of the filter body is formed by micro-gap elements delimiting the filter passages.

In the case of another different embodiment of the invention the filtration resistance of the established micro filtration layer is between 0.1 and 1.5 bar.

From the point of view of the filter equipment it may be favourable if the filter body is a pipe with cylindrical mantle shaped internal covering surface and an also cylindrical mantle shaped external covering surface, and, optionally, the internal delimiting surface of the base body encompassing the filter body has a cylindrical mantle shape, and furthermore the external covering surface of the filter body and the internal delimiting surface of the base body are coaxial with each other. In the case of another different embodiment of the invention the intake passage is established in the base body.

In the case of another embodiment of the filter equipment the filter body has a first end surface and a second end surface in a plane perpendicular to the longitudinal axis of the filter body, and the filter body is firmly fixed to the base body at the first end surface.

In accordance with the set objective the method according to the invention for the cleaning of water-based liquids with diatomaceous earth micro-filtration, - during which a liquid containing diatomaceous earth is made to flow through the filter body of the filtering equipment from the direction corresponding to the flow direction of the water-based liquid to be filtered, and a microfiltration layer is created on this surface of the filter body, following this the water-based liquid to be filtered is passed through the created microfiltration layer, and the filtered water-based liquid is created in this way, - is based on the principle that in order to produce the microfiltration layer of the filter body solid grains containing 50-95% diatomaceous earth and 5-50% cellulose and 5-50% pearlite and/or 5- 50% zeolite and/or 5-50% activated carbon and/or 1-5% Si0 ₂ with respect to total solids are mixed together, and using the liquid this mixture is transported to the filter body, after the microfiltration layer has been established the water-based liquid to be filtered is made to flow through the microfiltration layer of the filter body while in the mean time the filtration resistance of the filter equipment is measured, and the filtration process is continued until the filtration resistance increases to 5 bar, when a filtration resistance level of 5 bar is achieved the supply of the water-based liquid to be filtered is interrupted, the water-based liquid to be filtered is forced out of the receipt space of the base body suitable for accommodating the filter body by blowing in a gaseous medium, the used microfiltration layer is removed from the filter body, and the filtration is continued with the construction of a new microfiltration layer.

A further feature of the method according to the invention may be that in order to create the microfiltration layer the solid grains containing diatomaceous earth and cellulose and pearlite and/or zeolite and/or activated carbon and/or Si0 ₂ are mixed in clean water and this mixture is placed on the filter body. In the case of another embodiment of the method in order to create the microfiltration layer the solid grains containing diatomaceous earth and cellulose and pearlite and/or zeolite and/or activated carbon and/or Si0 ₂ are mixed into the water-based liquid to be filtered and this mixture is placed on the filter body.

In the case of another embodiment of the method according to the invention a scraping device running along the surface carrying the microfiltration layer is used to remove the used microfiltration layer. A piston corresponding to the size and shape of the surface carrying the micro filtration layer is used as the scraping device in the method.

From the point of view of the method it may be favourable if the fabrication of the microfiltration layer is continued for a duration of 10 to 300 seconds depending on the composition of the water-based liquid to be filtered.

The filtering equipment according to the invention and the method implemented with it have numerous preferable characteristics. The most important of these is that the efficiency of filtration is increased in such a way that pre-manufactured filter bodies with a constant composition do not have to be used and replaced in the equipment to correspond with the material that is being currently treated.

Another advantage is that due to the novel filtration layer composition and structure the risk of the filtration layer becoming damaged is reduced, and so the filtration becomes more reliable and more secure.

It is also an important advantage that the filtration layer that can be“fabricated” in a novel way in the filter body of the filter equipment may in all cases be adjusted to the composition of the substance to be treated and to the filtration requirement, and in this way, because the filter body does not have to be replaced, the specific filtration costs are also reduced.

Yet another advantage is that the filtering equipment is constructed from simple structural elements, its operation does not require special know-how, and the chances of it becoming faulty are low, therefore it acquisition and operation costs may be maintained at a favourable level. Further details of the filtering equipment according to the invention are presented on the basis of embodiments with reference to figures, wherein:

Figure 1 depicts a longitudinal cross-section of a possible version of the filtering equipment according to the invention.

Figure 1 shows a version of the filtering equipment according to the invention which may be used, among other applications, for cleaning the wastewater of paint plants. It may be observed that the base body 10 is located in the housing 1 , which encloses the receipt space 11. The filter body 20 may be found in the receipt space 1 1 of the base body 10, the first end surface 24 and second end surface 25 of which are fixed to the base body 10 so that the water-based liquid to be filtered 2 cannot pass between the base body 10 and the first end surface 24 not between the base body 10 and the second end surface 25.

In the case of the given embodiment the internal delimiting surface 13 of the base body 10 is a cylindrical mantle, and the filter body 20 is a cylindrical ring. The axis 14 of the internal delimiting surface 13 of the base body 10 is coaxial with the longitudinal axis 20a of the filter body 20. As a consequence of this the size of the space“T” taken in the radial direction between the internal delimiting surface 13 of the base body 10 and the external delimiting surface 23 of the filter body is constant.

Figure 1 illustrates well that the water-based liquid to be filtered 2 gets into the feed aperture 21 delimited by the internal delimiting surface 22 of the filter body 20 and the second end surface 25 of the filter body via the intake passage 4 established in the base body 10. While the filtered water-based liquid 3 may be discharged from the discharge space part“ET” of the receipt space 11 through the outlet passage 12 of the base body 10. This discharge space part“ET” is encompassed by the internal delimiting surface 13 of the base body 10 and the external covering surface 23 of the filter body 20.

The supply pipe 5 is connected to the intake passage 4, through which the water -based liquid to be filtered 2 is introduced into the filtering equipment. The supply pipe 5, in the given embodiment, is fitted with a pressure sensor body 41 and a regulation body 42. The pressure sensor body 41 and the regulation body 42 are connected to the control unit 40 in such a way that information may be transmitted between them. The control unit 40, and the connected pressure sensor body 41 and regulation body 42 are responsible for ensuring that the treatment of the water-based liquid to be filtered 2 is performed in the most favourable way. As the pressure sensor body 41 monitors the pressure and pressure change of the water-based liquid to be filtered 2 entering the intake passage 4. While the regulation body 42 prevents further water-based liquid to be filtered 2 from getting into the intake passage 4 if the value measured by the pressure sensor body 41 reaches a predetermined level on the basis of the evaluation performed by the control unit 40. It must be noted here that the control unit 40 is preferably a microcomputer programmed to perform a given task.

With regard to its structure the filter body 20 contains a series of filter passages 26 that have a strictly monotonously increasing cross-section“A” from the direction of the internal covering surface 22 delimiting the feed aperture 21 towards the direction of the external covering surface 23 that delimits the discharge space part“ET” from within, where the individual filter passages 26 are formed by micro-gap elements 27.

The micro filtration layer 30 actually performing the filtering is established on the internal covering surface 22 of the filter body 20 in such a way that the water-based liquid to be filtered 2 gets into the micro filtration layer 30 on the input side 31 of the microfiltration layer 30 opposite the internal covering surface 22 and leaves the microfiltration layer 30 from the internal covering surface 22 of the filter body 20.

The microfiltration layer 30 fabricated on the internal covering surface 22 of the filter body 20 must be removed after it has deteriorated from the internal covering surface 22 of the filter body 20. This is performed by the scraping device 50, which in this case is a piston 51 that is located in the housing 1 of the filtering equipment in the vicinity of the second end surface 25 of the filter body 20, and its diameter dimension and shape correspond to the diameter dimension and shape of the internal covering surface 22 of the filter body 20. Optionally the piston 51 is a flat circular disc.

The microfiltration layer 30 fabricated in the course of the operation of the filtering equipment in all cases corresponds to the composition of the water-based liquid to be filtered 2, as well as to the physical and/or chemical characteristics that the filtered water- based liquid 3 must be in possession of. After fabrication the microfiltration layer 30 created is formed by a mixture of solid grains containing 50% diatomaceous earth and 30% cellulose and 5% pearlite and 7% zeolite and 4% activated carbon and 4% Si0 ₂ . The microfiltration layer 30 is deemed to be “fabricated” when the filtration resistance of the microfiltration layer 30 falls between 0.1 to 1.5 bar, and the value measured by the pressure sensing body 41 does not reach the value of 5 bar.

It should be noted here that the given percentage values relate to the dry weight of the total amount of the given components, i.e. the dry proportions in total equal 100%. It is obvious then that the given percentage values will have different magnitudes in aqueous suspension. As the dry proportion as compared to the liquid must vary between 0.1 and 10 mass% in aqueous suspension so that it can be appropriately circulated for good fabrication of the microfiltration layer 30.

The operation of the filtering equipment according to the invention is presented in the following in detail in connection with method examples:

Example 1 :

In the given example swimming pool water is cleaned in the following way. First of all the microfiltration layer 30 is fabricated on the internal covering surface 22 of the filter body 20. In the course of this, outside of the filtering equipment, with respect to the total dry mixture, solid grains containing 50-95% diatomaceous earth, in this case 50% diatomaceous earth, 5-50% cellulose, in this case 34% cellulose, 5-50% pearlite, in this case 5% pearlite, 5-50% activated carbon, in this case 5% activated carbon, 5-50% zeolite, in this case 5% zeolite, and 1-5% Si0 ₂ , in this case 1% Si0 ₂ were mixed together, then the mixture made in this way was transported to the intake passage 4 of the filtering equipment with the help of clean water.

With the help of the water the mixture introduced into the intake passage 4 was first transported to the feed aperture 21 of the base body 10 of the housing 1 encompassed by the internal covering surface 22 of the filter body 20 inserted into the receipt space 11. As the water progressed along the filter passages 26 of the filter body 20 the solid grains in the aqueous mixture adhered to the internal covering surface 22 of the filter body. In this way the micro filtration layer 30 was gradually fabricated. When the filtration resistance of the microfiltration layer 30 reached the level of 0.1-305 bar required to treat the water-based liquid to be filtered 2, the value of 3.5 bar in the present case, the introduction of the aqueous mixture into the intake passage 4 was stopped.

It should be noted here that the filtration resistance of the fabricated microfiltration layer 30 was determined by the control unit 40 evaluating the signals arriving from the pressure sensing body 41 installed in the supply pipe 5. When the pressure sensing body 41 signalled the expected value to the control unit 40, then the control unit 40 shut off the regulation body 42, and so the transporting of the aqueous mixture to the filter body 20 serving for the fabrication of the microfiltration layer 30 was stopped.

The fabrication of the micro filtration layer 30 was performed during the course of 10- 300 seconds, which duration in the case of this water-based liquid to be filtered 2 was 150 seconds.

After the micro filtration layer 30 with the appropriate filtration resistance had been fabricated, the water-based liquid to be filtered 2 was released into the supply pipe 2, and at the same time as this the regulation body 42 was opened with the help of the control unit 40. In this way now the water-based liquid to be filtered 2 was released into the feed aperture 21 of the filter body 20 through the intake passage 4. The water-based liquid to be filtered 2 arriving into the feed aperture 21 was guided to the input side 31 of the microfiltration layer 30. In the way the water-based liquid to be filtered 2 was filtered by being passed through the fabricated microfiltration layer 30. In this way filtered water- based liquid 3 was produced from the water-based liquid to be filtered 2 that had passed through the microfiltration layer 30.

This filtered water-based liquid 3 was transported over the external covering surface 23 of the filter body 20 from the filter body 20 and then after being collected in the discharge space part“ET” forming a part of the receipt space 11 it was released from the receipt space 1 1 of the filtering equipment through the outlet passage 12.

The treatment of the water-based liquid to be filtered 2 was continued until the pressure sensing body 41 sent a signal to the control unit 40 that the filtration resistance of the filtering equipment measured at the intake passage 4 had reached 5 bar. At this time the regulation body 42 was closed with the help of the control unit 40, and the supply of the water-based liquid to be filtered 2 was suspended.

Following this the saturated microfiltration layer 30 was removed from the internal covering surface 22 of the filter body 20 with the help of the piston 51 of the scraping device 50. The cleaning of the internal covering surface 22 of the filter body 20 was performed by pushing the piston 51 all the way in the direction of the longitudinal axis 20a of the filter body 20 in the feed aperture 21 of the filter body 20. As the piston 51 progressed forwards the contaminated microfiltration layer 30 was separated off the internal covering surface 21 of the filter body 20 and pushed out of the feed aperture 21 through the opening of the base body 10 established in the vicinity of the first end surface 24 of the filter body 20.

In this way the cleaned internal covering surface 22 of the filter body 20 was brought into a state ready for the fabrication of a new microfiltration layer 30. Then in the way presented previously another clean water mixture was transported into the intake passage 4, and the treatment of the water-based liquid to be filtered 2 was performed intermittently.

Filtered water-based liquid 3 with an NTU value of 1 was created from the originally contaminated water-based liquid to be filtered 2 with an NTU value of 10, which was discharged from the filtering equipment through the outlet passage 12 of the filtering equipment.

Example 2:

In the given example the cleaning of the oil-contaminated water of an assembly plant as water-based liquid to be filtered 2 was carried out in the following way. In this case 50- 95% diatomaceous earth, in this case 50% diatomaceous earth, 5-50% cellulose, in this case 20% cellulose, and 5-50% activated carbon, in this case 10% activated carbon, furthermore 5-50% zeolite, in this case 20% zeolite were mixed into the water-based liquid to be filtered 2, in this way creating the mixture that was transported into the feed aperture 21 of the filter body 20. The cleaning process was performed in the same way as that disclosed in the case of example 1 with the difference that here the water-based liquid to be fdtered 2 itself was used as“carrier material” in order to fabricate the microfiltration layer 30.

In this way then the mixture is transported into the feed aperture 21 of the filter body 20 through the intake passage 4 with the help of the water-based liquid to be fdtered 2 an the microfiltration layer 30 was created from the grains coming to rest on the internal covering surface 22 of the filter body 20 from the water-based liquid to be filtered 2 flowing through the filter passage 26 of the filter body 20.

In this case in accordance with the different composition of water-based liquid to be filtered 2 the fabrication of the microfiltration layer 30 was performed for 120 seconds, when the filtration resistance of the microfiltration layer 30 reached the value of 4 bar.

In this case also the treatment of the water-based liquid to be filtered 2 was continued with the help of the fabricated microfiltration layer 30 until the filtration resistance measured by the pressure sensor body 41 reached the value of 5 bar.

Then the filtration was interrupted and the used microfiltration layer 30 was removed from the feed aperture 21 in the way illustrated in figure 1. Then a new microfiltration layer 30 was fabricated and the filtering was continued intermittently.

It should be noted here that not only the piston 51 but other suitable devices may also be used as the scraping device 50, with the help of which the used up microfiltration layer 30 may be removed from the surface of the filter body 20 carrying the microfiltration layer 30 without damaging the filter body 20.

It must also be mentioned here that the composition of the mixture serving for the fabrication of the microfiltration layer 30 is in all cases selected to correspond with the composition of the water-based liquid to be filtered 2 and the degree of filtration. In all cases, however, it is important that the microfiltration layer 30 itself is not used in the form of a prefabricated, solid filter insert, instead it is created as a part of the filtering process with the simultaneous monitoring of the filtration resistance, because in this way damage to the microfiltration layer 3 can be avoided. The filtering equipment according to the invention and the method that may be implemented with it may be used in all cases where water-based liquids to be filtered need to be reliably treated in a simple way, with good effectiveness and at a favourable operation cost level, and a given level of cleaning needs to be achieved in such a way that the treatment of different materials needs to be performed with the given filtering equipment.

List of references

housing water-based liquid to be filtered filtered water-based liquid intake passage supply pipe 0 base body 11 receipt space

12 outlet passage

13 internal delimiting surface

14 axis 0 filter body 20a longitudinal axis

21 feed aperture

22 internal covering surface

23 external covering surface

24 first end surface

25 second end surface

26 filter passage

27 micro-gap elements

30 microfiltration layer 31 input side 40 control unit 41 pressure sensing body

42 regulation body

50 scraping device 51 piston “A” cross-section “ET” discharge space part

“T” gap