AU2006349968A1

AU2006349968A1 - Backwashable filter unit having guide elements

Info

Publication number: AU2006349968A1
Application number: AU2006349968A
Authority: AU
Inventors: Bert Miecznik; Marek Novotny
Original assignee: Honeywell Technologies SARL
Current assignee: Garrett Motion SARL
Priority date: 2006-10-20
Filing date: 2006-10-20
Publication date: 2008-04-24
Also published as: WO2008046442A1; CN101641143A; EP2091627A1

Description

WO 2008/0,46442 PCT/EP2006/010145 FRITZ Patent- und PT 06/178/WO Rechtsanwhlte 10.20.2006/GR/GR/WO Ostentor 9 59757 Arnsberg Honeywell Technologies Sarl ECC Avenue de la Gottaz 34-36 1110 Morges "Backwashable filter unit having guide elements" CONFIRMATION COPY WO 2008/046442 - 2 - PCT/EP2006/010145 The invention relates to a backwashable filter unit for filtering a liquid, in particular in domestic water systems. The invention relates, in particular, to a backwashable filter unit comprising a main filter, through which the liquid flows when the filter unit is operating normally and when the filter unit is operating in a backwash mode. In addition, such a filter unit has a prefilter through which the liquid flows during backwash operation. The filter unit comprises a movable means for generating a cross flow (cross flow means) which is arranged directly upstream of at least part of the prefilter and/or of the main filter for cleaning this during normal operation and/or during backwash operation. The cross flow means comprises drive elements which can be acted upon by a flow of the liquid in order to drive the cross flow means. A backwashable filter unit of this type is known, in particular, from the publication bearing publication number DE 10 2005 004 552 Al. In the backwashable filter unit disclosed there, the liquid flows through the main filter from the outside inward during normal operation and from the inside outward during backwash operation. The displaceable main filter is assigned a prefilter which ensures the uninterrupted filtration function during the backwash processes. Between an inlet of the filter unit and the main filter, a means for shutting off the prefilter from the inlet is arranged, which can be opened or displaced for the purpose of backwashing. The liquid is then conducted from the outside inward via the prefilter. Since the inner space of the prefilter and the inner space of the main filter are connected to one another, the liquid filtered by the prefilter is routed into the interior of the main filter. To clean the main filter, the liquid is then routed outward through the main filter.

WO 2008/046442 - 3 - PCT/EP2006/010145 Cleaning can be reinforced by means of a spraying or splashing device (impeller) which may be mounted rotatably in the inner space of the main filter. To clean the prefilter, in the publication DE 10 2005 004 552 Al, the cross flow means is provided which, with the aid of the drive elements attached to it, can be driven by means of a flow of the washing stream of the liquid. The invention described in said publication basically functions highly reliably and gives satisfactory cleaning results. It was shown in practice, however, that the drive by the cross flow means may not be sufficient under highly unfavorable operating conditions to impart a stable and defined movement upon the cross flow means, particularly when additional frictional forces on the bearing of the cross flow means occur due to an unusually heavy particle load. This is where the present invention comes in. The problem on which the present invention is based is to set the flow in the filter unit such that a reliable and definite drive of the drive means of the cross flow means is possible. The problem on which the invention is based can, on the one hand, be solved by means of a filter unit as claimed in claim 1 and/or by means of a filter unit as claimed in claim 2. Accordingly, a filter unit according to the invention comprises one or more elements, what are known as guide elements, for guiding the flow of the liquid in one direction, the direction which the guide elements impart to the liquid being the direction of a circular path or of a helix. When a direction of this kind is imparted to the flow, the flow having this imparted direction is particularly suitable for driving a cross flow means.

WO 2008/046442 - 4 - PCT/EP2006/010145 Alternatively, it is sufficient, particularly in another design of a cross flow means, if the filter unit comprises one or more elements (guide elements) which are suitable and set up for conducting the flow of liquid in one direction onto the drive elements of the cross flow means. According to the invention, the prefilter of a filter unit according to the invention may be of hollow-cylindrical design. The cross flow means is then arranged upstream of the prefilter. The drive elements of the cross flow means may then be arranged on a circular path or on segments of a circular path. A filter unit according to the invention may have a housing which surrounds the main filter, the prefilter and the cross flow means. The filter unit may have means for shutting off (shut-off means) the prefilter against a liquid flowing into the filter unit during normal operation. The guide elements may be attached to a first of the shut-off means or be connected in one piece to the shut-off means. It is likewise possible for the guide elements to be arranged on the inner wall of the housing. The guide elements are advantageously arranged in a space between the housing and the first shut-off means or project into this space. According to the invention, the guide elements may form, together with the housing and the first shut-off means, one or more ducts. The ducts and/or the guide elements may be of helical design. The helices which form the ducts and/or the guide elements may have an angular circumference of 1900 to 2500, but preferably an angle of 210* to 270*. In the WO 2008/046442 - 5 - PCT/EP2006/010145 region of an outlet-side issue of the duct, the helix or helices may have a pitch of 0* to 200. That is to say, the liquid flows out of the duct virtually along a circular path. An outlet-side issue of the ducts may have a width which is 25% to 50%, but preferably 29% to 36%, of the diameter of the first shut-off means. The filter unit preferably has two guide elements which are arranged symmetrically to one another. The two guide elements then form, together with the first shut-off means and the housing, two ducts. The prefilter of a filter unit according to the invention may be displaceable so as to change from normal operation to backwash operation. The first shut-off means may be of bell-shaped design, and the prefilter can be pushed into the first shut-off means in normal operation and be pulled out of the first shut-off means in backwash operation. A space between the prefilter and the housing, on the one hand, and a space between the main filter and the housing, on the other hand, may be separated from one another in backwash operation, preferably by means of a second shut-off means and a third shut-off means. An inflow of the filter unit is advantageously connected directly to the space between the housing and the main filter in normal operation and directly to the space between the housing and the prefilter in backwash operation. Further features and advantages of the present invention become clear from the following description of preferred exemplary embodiments, with reference to the accompanying figures in which: WO 2008/046442 - 6 - PCT/EP2006/010145 fig. 1 shows a part section through a filter unit according to the invention in normal operation, fig. 2 shows a detail from fig. 1 from the upper region of the filter unit, in section, fig. 3 shows a further detail from the upper region, with further parts shown in section, fig. 4 shows a detail from the lower region of the filter unit in normal operation, fig. 5 shows a part section through the filter unit according to fig. 1 to 4 in backwash operation, fig. 6 shows a detail from the upper region of the filter unit in backwash operation, fig. 7 shows a detail of the filter unit in backwash operation, corresponding to fig. 6, with further parts shown in section, and fig. 8 shows a detail of the filter unit in backwash operation from the lower region. The filter unit 1 according to the invention, illustrated in figures 1 to 8, has a fitting 10 which may be connected via an inflow connection piece 11 and an outflow connection piece 13 respectively to an incoming line and an outgoing line. The inflow region 12 and the outflow region 14 of the fitting are separated from one another. A manometer for monitoring WO 2008/046442 - 7 - PCT/EP2006/010145 the outflow-side pressure is connected to a measuring connection piece 16 in the outflow region. Furthermore, in the inflow-side region 12, a connection piece 17 for connecting a further manometer or other measuring instrument for monitoring the inflow is arranged, which in the present case, however, is closed by means of a plug 140. The fitting 10 has, furthermore, a filter connection piece 15, to which a housing 20 in the form of a filter bowl is connected, as is also customary in the known filter units. The housing 20 has a backwash outflow 21, through which water can emerge from the filter unit in backwash operation. A ball cock 30 for closing the outflow 21 is arranged in the backwash outflow 21. The ball cock 30 and the arrangement of the ball cock 30 in the backwash outflow 21 are in this case configured in the conventional way. The outflow 14 of the fitting 10 is connected via a connection piece 18 projecting into the filter connection piece 15 to the inner space of the housing 20. This connection piece 18 is followed by a first shut-off means 50. This shut-off means is of bell-like design and may have the flow passing through it from the bottom upward (see, in particular, fig. 3). An upper end of a displaceable filter insert 80 of the filter unit 1 is arranged in the first shut-off means. For this purpose, the filter insert 80 has at its upper end a ring 85 which is guided in the bell-shaped shut-off means 50. The filter insert 80 has at its lower end a bottom 83 onto which a bearing journal 84 is integrally formed. This bearing journal 84 is arranged displaceably in a ring 111 of a bearing means 110. This ring 111 forms a bearing bush in which the bearing journal 84 is mounted. The ring 111 of the bearing means 110 is connected to the housing 20 in the region of the backwash outlet 21. Moreover, the filter WO 2008/046442 - 8 - PCT/EP2006/010145 insert is led in the lower region of the housing 20 through a guide means 120 having a ring 121 which, when the filter unit 1 is in normal operation, co-operates with the outside of the filter insert bottom 83, in order to shut off the region of the backwash outlet 21 from the throughflow volume of the fitting 10. Wedge-shaped elements 122 pointing in the direction of the backwash outlet 21 are fastened to the ring 121. The wedge-shaped elements 122 are in this case fastened to the inside of the ring at a uniform distance from one another and guide the filter insert 80 when the latter moves toward the backwash outlet 21 during backwash operation. Since in this case the bottom 83 connected to the filter insert 80 likewise moves away from the ring 121, a throughflow through the interspaces between the wedge-shaped elements 122 is made possible in backwash operation. The guide means 120 is held in the lower region of the housing 20 via the bearing means 110. The filter insert 80 is supported against a spring 130 in the lower region of the filter unit 1. For this purpose, the spring 130 is arranged between the underside of the bottom 83 and the bearing means 110. The spring is prestressed such that the filter insert is pressed upward. This is the position which the filter insert has during the normal operation of the filter unit 1. The filter insert may be subdivided between the bottom 83 and the upper ring 85 into two regions, to be precise the region of the prefilter 81 and the region of the main filter 82. The region of the prefilter is arranged in the upper part of the filter insert and during normal operation lies completely within the first shut-off means 50. By contrast, the main filter is provided in the lower region of the filter insert 80.

WO 2008/046442 - 9 - PCT/EP2006/010145 A second shut-off means 60 is connected firmly to the filter insert between the region of the prefilter 81 and the region of the main filter 82. The second shut-off means 60 is formed by a ring of L-shaped cross section which is arranged on the outside of the essentially hollow-cylindrical filter insert 80. When the filter unit 1 is in normal operation, this second shut-off means co-operates with the first shut-off means 50 and prevents an ingress of water into a space between the first shut-off means 50 and the prefilter 81. By contrast, in backwash operation, the second shut-off means 60 co-operates with a third shut-off means 70 which, designed in the form of a ring, is arranged on the inside of the housing 20. In backwash operation, the co-operation of the second shut-off means and of the third shut-off means 70 prevents a direct connection of the space between the housing 20 and the prefilter 81, on the one hand, and the space between the housing 20 and the main filter 82, on the other hand. A cross flow means 100 for generating a cross flow directly upstream of part of the prefilter 81 is arranged between the first shut-off means 50 and the prefilter 81. This cross flow means is in the form of a hollow cone frustum which is arranged rotatably on the second shut-off means 60. The cross flow means 100 is displaceable together with the filter insert 80 and the second shut-off means 60. The cross flow means has drive elements in the form of turbine blades 101 which, during throughflow, cause rotation when the filter unit 1 is in backwash operation. Moreover, the cross flow means has two elements 102 which route the cross flow via the prefilter 81 and are designated hereafter as guide elements 102. The guide elements 102 are integrally formed, opposite one WO 2008/046442 - 10 - PCT/EP2006/010145 another, on a ring 103 on which the turbine blades 101 are also integrally formed. The guide elements 102 have a concave inner surface which bears against the prefilter 81. A duct is introduced in each case into this concave inner surface. This duct is continued through the ring 103 and terminates with a lower end above the second shut-off means 60. The shut-off means 60 has in the collar 61 running perpendicularly with respect to the filter insert 80, fig. 7, bores at which the ducts of the cross flow means terminate. The duct terminates with its other end in the guide element 102 without issue. A liquid which is inside the prefilter 81 can enter the ducts through the prefilter 81. The liquid is then conducted through the duct through the ring 103 and the bores in the collar 61, so that the liquid can pass through the second shut-off means 60. Consequently, in backwash operation, a liquid stream is possible from the outer space of the prefilter 81, through the prefilter 81 into the interior of the prefilter 81, out of the interior of the prefilter 81 once again through the prefilter 81 into the duct of the cross flow means 100. The liquid can then flow out of the duct through the bores in the collar 62 of the second shut-off means into the space surrounding the main filter 82 and further on to the backwash outlet 21. As a result of the backflow out of the interior of the prefilter through the prefilter 81 into the duct and the cross flow through the duct along the outer surface of the prefilter 81, particles can be released from the prefilter 81 and washed away. This is already described in more detail in the publication DE 2005 004 552 Al. Guide elements 51 are attached on the outside of the first shut-off means 50. These guide elements 51 are laid helically around the bell-shaped body of the first shut-off means 50 and are attached to this or preferably formed in one piece with this. The helix WO 2008/046442 - 11 - PCT/EP2006/010145 formed by the guide elements 51 tapers in the throughflow direction. As a result, the liquid has imparted to it at the helix exit a direction which is approximately perpendicular to the main flow direction of the washing medium. In order to avoid a flow stall edge, the helix exit may have a residual slope of about 50 to 200. The two guide elements are configured axially symmetrically to the mid-axis of the bell-shaped body of the first shut-off means 50. By means of the guide elements, a liquid flowing into the interspace between the first shut-off element 50 and the housing 20 is both accelerated in a vector directed exactly at the turbine blades 101 and acted upon by an internal swirl. In backwash operation, this vector causes a better flow upon the turbine blades 101 of the cross flow means 100. At the same time, due to the internal swirl of the liquid, a better force transmission from the onflowing liquid to the turbine blades 101 is achieved. A continuous drive of the cross flow means 100 can thereby be ensured to a sufficient extent in any operating state of backwash operation. By contrast, when the backwash device 1 is in normal operation, there is no need for a swirl to be generated by means of the guide elements 51. An impeller 90 which has spray nozzles 91 and the function of which is already known from DE 2005 004 552 Al is mounted rotatably in the filter insert 80.

Claims

1. A backwashable filter unit (1) for filtering a liquid, in particular in domestic water systems, characterized in that the filter unit (1) comprises one or more elements (guide elements 51) for guiding the flow of liquid in one direction, and the direction which the guide elements (51) impart to the liquid is the direction of a circular path or of a helix.

2. A backwashable filter unit (1) for filtering a liquid, in particular in domestic water systems, in particular as claimed in claim 1, the filter unit comprising the following features: - the filter unit (1) comprises a main filter (82) through which the liquid flows when the filter unit (1) is in normal operation (fig. 1 to 4) and is in backwash operation (fig. 5 to 6); - the filter unit (1) comprises a prefilter (81) through which the liquid flows during backwash operation (fig. 5 to 6); - the filter unit comprises a displaceable means for generating a cross flow (cross flow means 100) directly upstream of at least part of the prefilter (81) and/or upstream of part of the main filter (82) so as to clean this in normal operation and/or in backwash operation; - the cross flow means (100) comprises drive elements (101) which can be acted upon by a flow of the liquid in order to drive the cross flow means (100); - the filter unit (1) comprises one or more elements (guide elements 51) for guiding the flow of the liquid in one direction onto the drive elements (101). WO 2008/046442 - 13 - PCT/EP2006/010145

3. The filter unit as claimed in claims 1 and 2, characterized in that the prefilter (81) is of hollow-cylindrical design.

4. The filter unit as claimed in claim 3, characterized in that the cross flow means (100) is arranged upstream of the prefilter (81).

5. The filter unit as claimed in claim 3 or 4, characterized in that the drive elements (101) of the cross flow means (100) are arranged on a circular path or on segments of a circular path.

6. The filter unit as claimed in one of claims 2 to 5, characterized in that the filter unit (1) has a housing (2) which surrounds the main filter (82), the prefilter (81) and the cross flow means (100).

7. The filter unit as claimed in one of claims 2 to 6, characterized in that the filter unit (1) has means for shutting off (shut-off means 50, 60) the prefilter against a liquid flowing into the filter unit during normal operation.

8. The filter unit as claimed in claim 7, characterized in that the guide elements (51) are attached to a first of the shut-off means or are connected in one piece to this.

9. The filter unit as claimed in claim 6 and claim 7 or 8, characterized in that the guide elements (51) are arranged in a space between the housing (2) and the first shut-off means (50).

10. The filter unit as claimed in claim 9, characterized in that the guide elements (51) form, WO 2008/046442 - 14 - PCT/EP2006/010145 together with the housing (2) and the first shut-off means (50), one or more ducts.

11. The filter unit as claimed in claim 10, characterized in that the ducts are of helical design.

12. The filter unit as claimed in one of claims 1 to 11, characterized in that the guide elements (51) are of helical design.

13. The filter unit as claimed in claim 11 or 12, characterized in that the helices which form the ducts and/or the guide elements (51) have an angular circumference of 190* to 2500, preferably an angle of 2100 to 2700.

14. The filter unit as claimed in one of claims 11 to 13, characterized in that the helices have a pitch of 00 to 200 at least in the region of an outlet-side issue of the duct.

15. The filter unit as claimed in one of claims 10 to 14, characterized in that the ducts have an outlet-side issue which has a width which is 25% to 50%, preferably 29% to 36%, of the diameter of the first shut-off means (50).

16. The filter unit as claimed in either one of claims 1 and 2, characterized in that the filter unit (1) has two guide elements (51) which are arranged symmetrically to one another.

17. The filter unit as claimed in one of claims 2 to 16, characterized in that the prefilter (81) is displaceable so as to change from normal operation to backwash operation. WO 2008/046442 - 15 - PCT/EP2006/010145

18. The filter unit as claimed in one of claims 7 to 17, characterized in that the first shut-off means (50) is of bell-shaped design.

19. The filter unit as claimed in claims 17 and 18, characterized in that the prefilter (81) is pushed into the first shut-off means in normal operation and is at least partially pulled out of the first shut-off means (51) in backwash operation.

20. The filter unit as claimed in one of claims 6 to 19, characterized in that a space between the prefilter (81) and the housing (2), on the one hand, and a space between the main filter (82) and the housing (2), on the other hand, are separated from one another in backwash operation.

21. The filter unit as claimed in one of claims 6 to 20, characterized in that an inlet (12) of the filter unit (1) is connected to the space between the housing (2) and the main filter (8) in normal operation and is connected directly to the space between the housing (2) and the prefilter (81) in backwash operation.