Device for separating a heterogeneous mixture of matter and method for cleaning a filter unit

Abstract

The invention relates to a device (10) for separating a heterogeneous mixture of matter into at least one retentate and one filtrate, comprising a housing (12) which is subdivided into a chamber for the heterogeneous mixture (20) of matter having at least one feed (14) and a filtrate chamber (21) having at least one outlet (16), a filter unit (22) which comprises at least one filter element (24), wherein the filter unit (22) is arranged in the chamber for the heterogeneous mixture (20) of matter, and a rinsing system (46, 47, 50, 50′) for cleaning the filter unit (22),
wherein the rinsing system (46, 47, 50, 50′) has at least one rinsing port (46, 47) which is constructed so as to introduce a stream, oriented tangentially to the shell surface (54), of a first washing medium into the chamber for the heterogeneous mixture (20) of matter. The invention further relates to a method for cleaning a filter unit.

Claims

1. A filtration apparatus comprising: a filter housing (12) having an inlet (14) and an outlet (16); a filter base (26) within said housing dividing said housing into an unfiltered or retentate chamber (20) and a filtrate chamber (21), said base having a plurality of holes (38) extending therethrough; a plurality of filter candles (24) corresponding in number to the number of holes (38) in said base (26), and sealingly extending from said holes into said unfiltered or retentate chamber (20); an open holding system in said unfiltered or retentate section including: a plurality of sleeves (32) corresponding in number and partially enclosing each of said plurality of filter candles (24); and one or more webs (34) connecting said sleeves (32) to each other and/or said filter housing (12); a rinsing system comprising a plurality of rinsing ports (47) which are arranged in the lower region (48) of the housing (12), said rinsing ports including a tubular elongation (60) opening into said unfiltered or retentate chamber, said tubular elongation being constructed and arranged to tangentially deflect a stream of a first washing medium out into said unfiltered or retentate chamber, tangentially at a housing shell surface (54).

Description

(1) The invention will be described in more detail hereinafter with reference to drawings.

(2) In the drawings:

(3) FIG. 1 shows a schematic representation of a device according to the invention for separating a heterogeneous mixture of matter in side view,

(4) FIG. 2 shows a schematic representation of the device according to the invention according to FIG. 1 in plan view including spray rings,

(5) FIG. 3 shows a further embodiment of the rinsing port according to FIG. 2, and

(6) FIG. 4 shows a detail view of the holding system in side view,

(7) FIG. 5 shows a schematic representation of the device according to the invention as shown FIG. 1 in plan view including spray arms.

(8) FIG. 1 shows in diagrammatic representation a sectional view of the device 10 according to the invention. The device 10 according to the invention is not restricted to a field of application and can be used with any desired heterogeneous mixtures of matter which comprise a solids fraction and a liquid fraction. For example, the device 10 according to the invention can be used for preparing process water in the chemical and mechanical industries.

(9) The device 10 according to the invention comprises a housing 12 having a substantially cylindrical shell surface and also a feed 14 and an outlet 16. The housing 12 is further subdivided into a chamber for the heterogeneous mixture of matter chamber 20 and a filtrate chamber 21. The feed 14 is situated in the upper region 18 of the housing 12, wherein a heterogeneous mixture of matter is introduced into the chamber for the heterogeneous mixture 20 of matter via the feed 14.

(10) In the housing 12 a filter unit 22 is introduced which comprises a plurality of filter candles 24 on a filter base 26. The filter candles 24 are typically constructed as cylindrical filter elements, wherein a filter medium, such as a fabric made of plastics, ceramics and/or metal, can be wound or stretched layerwise on a support. In the lower region 36, the filter candles 24 are mounted on a filter base 26 which has, for example, a number of holes 38 corresponding to the number of the filter candles 24. These form the outlet of the filter candles 24, the filtering effect of which consequently occurs in the event of flowthrough from the outside, that is to say the chamber for the heterogeneous mixture of matter, toward the inside.

(11) Owing to the longitudinal extension of the filter candles 24 and the vertical arrangement thereof in the housing 12, in addition, in the upper region 28 of the filter candles 24, a holding system 30 is provided which fixes the filter candles 24 within the housing 12. In the upper region 28, the filter candles 24 are held by a system of sleeves 32 which enclose the individual filter candles 24. The sleeves 32 are, as is shown in FIG. 2, connected to one another by webs 34 and to the housing 12.

(12) If a heterogeneous mixture of matter which can be, for example, a suspension, flows through the filter candles 24, this heterogeneous mixture of matter is substantially separated into a solids fraction as retentate and a liquid fraction as filtrate. In this case the solids fraction, for example an undissolved salt, arises as filter cake outside the filter candles 24 and the liquid fraction is passed as filtrate into the interior of the filter candles 24. Via the outlet 16 on the housing base 40, the filtrate is passed out of the device 10. In addition, a venting opening 42 is provided on the housing cover 44 in order to adjust appropriately the pressure difference between feed- and outlet-side surfaces of the filter candles 24.

(13) During filtration, the retentate accumulates on the surface of the filter candles 20 as filter cake and reduces the filtering efficiency. For regeneration of the filter candles 24, that is to say for erosion of the filter cake, a rinsing system is provided. The rinsing system comprises rinsing ports 46 which are arranged tangentially in the lower region 48 of the housing 12 and open out into the chamber for the heterogeneous mixture 20 of matter and introduce a washing medium, for example water, into the housing 12. The rinsing ports 46, by means of the tangential orientation, generate a circular flow in the lower region 48 of the housing 12 which supports the dissolution, rinsing and/or discharge process of the filter cake.

(14) The rinsing system further comprises rinsing rings 50, 50′, which are situated within the chamber for the heterogeneous mixture 20 of matter. The rinsing rings 50, 50′ are designed in such a manner that, by spraying the filter candles 24 with a washing medium, for example water, the filter cake is mechanically eroded. In the embodiment shown in FIG. 1, two spray rings 50, 50′ are provided with spray nozzles 52, wherein one spray ring 50 is situated above the filter candles 24 and a further spray ring 50′ is introduced between the filter candles 24. The spray rings 50, 50′ can be fastened in this case on the housing 12 or on the filter candles 24 by means of suitable holders.

(15) In the embodiment shown in FIG. 1, the spray ring 50 above the filter candles 24 has a greater diameter than the spray ring 50′ which is situated between the filter candles 24. The arrangement of the spray rings 50, 50′ and the diameter thereof, however, can be adapted to any arrangement of filter candles 24, in such a manner that an optimum mechanical cleaning effect is achieved. The spray nozzles 52 of the spray rings 50, 50′, in the embodiment shown in FIG. 1, are orientated in such a manner that the washing medium is sprayed downwards to the housing base 40. In general, the orientation of the spray nozzles 52 can be selected so as to be pivotable or, according to positioning and number of the spray rings 50, 50′, selected in such a manner that an optimum cleaning effect is achieved.

(16) FIG. 2, in a schematic representation, shows the device 10 according to the invention of FIG. 1 in plan view including spray rings 50, 50′. Through the feed 14 on the housing 12, the heterogeneous mixture of matter that is to be separated is introduced into the chamber for the heterogeneous mixture 20 of matter. The filter unit 22 which comprises a plurality of filter candles 24 that are fastened in the housing 12 is situated there. In the lower region 36, the filter candles 24 are mounted in a filter base 26 which, for example, has a number of holes 38 corresponding to the number of the filter candles 24.

(17) In the upper region 28, the filter candles 24, owing to the length thereof, are further fixed by a holding system 30. The holding system 30 comprises sleeves 32 which enclose the individual filter candles 24 at the periphery. The filter candles 24 are thereby burdened in a planar manner and are therefore held in position in a gentle manner. In order that the cleaning effect of the rinsing system, in particular of the spray rings 50, 50′, is not impaired, the holding system 30 is constructed so as to be open, by connecting the sleeves 32 to one another by means of webs 34. The sleeves 32 which are connected to one another by webs 34 are additionally fastened to the housing 12 by suitable means, for example further webs 34. Thus the holding system can be fixed, for example by means of further webs 34, to the shell surface 54 of the housing 12, the housing base 40, or the housing cover 44.

(18) In addition, the device 10 is equipped with a rinsing system 46, 50, 50′ which erodes the filter cake arising owing to the filtering action on the filter candles 24. The rinsing system 46, 50, 50′ comprises rinsing ports 46 which are arranged tangentially on the shell surface 54 of the cylindrical housing 12. In the embodiment shown in FIG. 2, in total three rinsing ports 46 are arranged regularly on the cylindrical shell surface 54 of the housing 12. This design permits an improved rinsing process to be provided with increased dissolution and discharge capacities.

(19) In general, the number and arrangement of the rinsing ports 46 can be adapted as desired to the desired cleaning effect. Thus, the rinsing ports 46 can be arranged in regular or irregular spacings on the cylindrical shell surface 54 of the housing 12.

(20) In addition to the rinsing ports 46, the rinsing system 46, 50, 50′ comprises spray rings 50, 50′ having spray nozzles 52 which are situated in the chamber for the heterogeneous mixture 20 of matter. The spray rings 50, 50′ with spray nozzles 52 mechanically erode the filter cake by spraying the filter candles 24 with a washing medium, for example water. In the embodiment shown here, the rinsing system 46, 50, 50′ provides two spray rings 50, 50′ with spray nozzles 52 which have different diameters. In this case the spray ring 50′ having the smaller diameter is placed between the filter candles and the spray ring 50 having the larger diameter than spray ring 50′ is situated above the filter candles 24.

(21) In FIG. 3, an alternative embodiment of the rinsing ports 47 of the rinsing system 46, 47, 50, 50′ is shown. The rinsing ports 47 are introduced orthogonally into the shell surface 54 of the housing 12 and comprise means for the tangential deflection of the stream of the first washing medium. The deflection means 58 of the embodiment shown in FIG. 3 are constructed as a tubular elongation 60 of the rinsing ports 47 which project into the chamber for the heterogeneous mixture of matter. Thus, in a simple manner, a circular stream is generated from a tangential stream of washing medium, which provides an improved rinsing process with increased dissolution and discharge capacities.

(22) The embodiments shown in FIGS. 2 and 3 can also be used in combination, wherein the rinsing ports can be arranged regularly or irregularly on the cylindrical shell surface 54 of the housing 12.

(23) FIG. 4 shows a detail view of the above described holding system 30, which comprises sleeves 32 that are connected to one another via webs 34, and fixes the filter candles 24 together with the filter base 26 within the housing 12. The sleeves 30 for this purpose have an internal circumference which substantially corresponds to the outer circumference of the filter candles 24. The sleeves can thereby enclose the filter candles 24 at the periphery. Between the individual sleeves 32 enclosing the filter candles 24, there are further provided webs 34 which connect the individual sleeves 32 to one another. The system of sleeves 32 and webs 34 thus constructed can be fastened by further webs 34 on the housing 12, for example the shell surface 54 of the housing 12, the housing base 40 or the housing cover 44. The webs 34 can be constructed as a web sheet metal which runs between the sleeves 32. In this manner an open holding system 30 can be provided which does not affect the cleaning action of the rinsing system 46, 50, 50′, in particular of a spray ring 50 arranged above the filter candles 24.

(24) FIG. 5, in a schematic representation, shows the device 10 according to the invention of FIG. 1 in plan view including spray arms 51, 51′. The embodiment of FIG. 5 essentially corresponds to the embodiment of FIG. 2. In contrast to FIG. 2 the spray nozzles are provided on spray arms 51, 51′, which are fed by one connection 53. Furthermore, the arrangement of filter elements 24 in a honey comb structure 56 is illustrated.

EXAMPLES

(25) Filter without the cleaning system according to the invention:

(26) For filters with a cleaning system known in the art a cleaning period of about 2 hours is required including 10 m.sup.3 of water. In order to reach the desired cleaning effect, the filter is opened and the candles are further sprayed using a hose assembly. This cleaning step takes about 1 hour and uses up about 1 of 10 m.sup.3 water. This way the cleaning is overall time consuming and involves further danger, as the filter is cleaned with hot water.

(27) Filter including the cleaning system according to the invention:

(28) For filters with a cleaning system according to the invention comprising rinsing port arranged tangentially to the cylindrical shell and two spray rings at different heights a cleaning period of about 1 hour is required including 5 m.sup.3 of water. Opening and closing of the system is not required. Thus the filter can be cleaned in a efficient way reaching the desired cleaning effect. In particular compared to the state of the art, the time and water consumption is drastically reduced.

LIST OF REFERENCE SIGNS

(29) 10 device for separating a heterogeneous mixture of matter 12 housing 14 feed 16 outlet 18 upper region of the housing 20 chamber for the heterogeneous mixture of matter 22 filter unit 24 filter candle 26 filter base 28 upper region of the filter candle 30 holding system 32 sleeve 34 web 36 lower region of the filter candle 38 hole in the filter base 40 housing base 42 venting opening 44 housing cover 46 rinsing port 47 rinsing port 48 lower region of the housing 50, 50′ spray rings 51, 51′ spray arms 52 spray nozzle 53 connection for spray arms 54 cylindrical shell surface 56 honey comb structure