FILTER DEVICE AND METHOD TO THEIR INTERPRETATION
The invention relates to a filter device for purification and/or at least for partial dealkalization of raw water, comprising of a raw water inlet and a pure water outlet, with a flow channel segment and with a filter line A with a first filtration segment, and with a dilution valve and a dilution line B with a second filtration segment, which is connected by means of a separation device with the raw water inlet on one side, and with a connection device with the pure water outlet on the other side, whereby both the filtration segments are arranged in an inner container. The invention is also related to an inner container for this kind of filter devices. In the filter devices, in particular those with dealkalization filters, which are used in beverage and coffee vending machines, a dilution device is employed in general. In the latter, usually large water filters are used, which typically have inner containers with volume of the order of 1.5 to 25 I, and are filled, for instance, with an ion exchanger resin or other materials, which can mainly remove the carbonates, and, where applicable, depending on the type of the filter material used, also nitrates, chlorides and sulfates, or other substances, from the water. Since the carbonate hardness of the raw water is not always and everywhere the same, and, on the other hand, since the carbonate hardness has a significant effect on the taste, particularly of coffee, it is necessary to dilute the filtered water with unfiltered raw water. In DE 196 48 405.7, a terminal multiplexer for large sized water filters has been described, which is comprised of an inlet line for inflow into the filter and an outlet line for the outflow of the filtered water from the filter, whereby a metering valve is provided in a bypass connecting the inlet and the outlet lines, which enables adjustment, as required, of the blending of the filtered and unfiltered water in the outlet line. However, it has been found that such dilution equipment can ensure the adjusted dilution portion only if the volume flow is high, that is, if the volume flow, which also depends very much on the suction capacity of the consumer device, is in the range of, for example, 100 to 300 l/h. Volume flow always refers to the volume flow with a continuous flow. If the volume flow is low, there is deviation from the value preset using the dilution valve, such that the unfiltered raw water portion increases with the decreasing volume flow. In that case, it is necessary to correct it with a metering valve, which has hitherto not been easy, because the deviation from the preset amount of dilution is not known in general. Furthermore, there are dilution valves, which effect both the filter line as well as the dilution line during the adjustment. Such dilution valves require a lot of mechanical manipulation and are consequently expensive. DE 199 58 648.9 refers to a water filter device, which is comprised of a separation device for dividing the raw water flowing in through the inlet into two partial flows. Both the partial flows pass in part through different filter lines. Thereby, the ratio of the partial flows can be adjusted by means of a valve. With this filter device, the problem is to be solved in such a fashion that, on one hand, even when the water taken out from the device is not completely dealkalized, all the other undesirable substances are completely removed from the water. In order to achieve this, one partial flow flows through the commonly used ion exchanger resin and, for example, activated carbon, and the other partial flow flows, for example, only through activated carbon. The problem of changing the dilution portion with respect to the total quantity for low flow rates is, however, still not addressed here. In DE-AS 15 36 899 a combined pressure filter with upward flow and downward flow filters is described, in which the filtrate is removed evenly from the entire cross section of the fine grain filter mass with as low pressure decline as possible, without using a device for removal. In this case, the upward flow filter is built within the downward flow filter. The liquid to be filtered is supplied not only from above but also from below, so that both the filtration flows unite in the downward flow filter. Hence, the task of the invention is to create a filter device with a dilution device and an inner container, which forms a constituent part of the filter device, in which the dilution portion remains largely constant with the variations in the total volume of the flow. This task is solved with a filter device, in which the flow characteristics of the component of the dilution line B, defined by the pressure loss function ΔpB(VB) are adapted according to the flow characteristics of the component of the dilution line A, defined by the pressure loss function ΔpA(VA), such that the dilution condition is satisfied for at least one dilution portion X with X=VB/(VA+VB) for volume flows between V1=10 l/h to V2=120 l/h (first volume flow range) for at least a second volume flow range of at least 5 l/h within the first volume flow range: The pressure loss function ΔpB(VB) refers to the function which describes the pressure loss between the branching points of the distributor and the connection devices. Thereby, the throttles that may possibly be arranged in or before the distributor or analogous devices are not taken into consideration. The pressure loss functions are obtained by adding the corresponding functions of the successively arranged components in the lines A and B. Thereby, for the sake of simplification, for instance, the pipe connection of the line A to a flow channel section is shown together as one. The filtration segments are the filters arranged in it, which have decisive influence on the flow characteristic, and consequently on the corresponding pressure loss function, in that segment. It turned out that by adapting the layout of the components, the pressure loss function ΔpB can be adjusted according to the pressure loss function ΔpA to such an extent that for different volume flows, the set dilution portion remains essentially the same. While designing the components of the lines A and B, at first a dilution portion X is given, which preferably corresponds to the dilution portion, with which the filter device is usually to be operated. This dilution portion is also called basic layout. Further, the components are designed for a volume flow range, which responds especially sensitively to the dilution portion. It was found that, while designing the components, it is not necessary to take the entire range of the volume flow area into account, for which the filter device can be used. Rather, it was found that, in the design, a first volume flow range, which can be defined by the thresholds values V1=10 l/h and V2=120 l/h, and within this first range, at least one second volume flow range, with range of at least 5 l/h, is sufficient. Main influence on the flow characteristic of the pressure loss function ΔpB(VB) within this range between V1 and V2 is exercised by the size of the filter device, and, in particular by the volume of the inner container, so that the range of the second volume flow can fluctuate within the limit V1 and V2. When the adaptation of the components of the filter device was undertaken, it was found that even in case of smaller volume flows, that is, in the range from V1 up to the beginning of the second volume flow range, the dilution portion virtually does not change with the variations in the total volume of the flow. Preferably, the threshold value G is 0.10, especially 0.05. Preferred values for the range width of the second volume flow range are at least 10 l/h, especially at least 15 l/h. Preferably the dilution valve and the second filtration section are designed in such a way that, in the second volume flow range, the following condition is fulfilled: ΔpB1(VB)<ΔpB2(VB2), whereby ΔpB1(VB) indicates the pressure loss function of the dilution valve and ΔpB2(VB) indicates the pressure loss function of the second filtration segment. In this case, the flow characteristic of the second filtration segment dominates the flow characteristic of the entire dilution line B. When adapting the components, it is preferable that the dilution valve is in a completely open state and that the flow characteristic ΔpA1(VA) of the flow channel segment is adjusted according to the flow characteristic ΔpA2(VB) of the dilution valve. The layouts of the two filtration segments are then matched to one another in such a way that the pressure loss functions ΔpA2(VA) and ΔpB2(VB) of the first and the second filtration segments are approximately equal to each other. Preferably, the flow areas QA and QB, are expressed in m2, and the distances hA and hB, expressed in m, of the first and the second filtration segments, are designed in such a way that the following equation for the pressure loss factors DA and DB, expressed in kPah/m2, is satisfied for both filtration segments: If there is grist, the distances hA and hB are defined by the heights of the filter beds. In case of sinter blocks, which are built, for example, cylindrically with a central filtrate channel and the flow enters from the outside, the distance is defined by the thickness of the wall of the cylinder. The cylinder jacket forms, in this example, the region of the flow. Preferably, the cross sectional area QA lies in the range of 5 cm2 to 600 cm2 and QB lies in the range of 1 cm2 to 300 cm2. In case of filter grist, the pressure loss coefficients are determined by the grain size and in case of sinter bodies by the pore size. The grain sizes lie preferably in the range of 0.1 to 2 mm, whereby these values correspond to the mean value with normal distribution. Preferably, the activated carbon is used as the filter grist. The filter material of the filter lines A and/or B is preferably a filter block, in particular a sintered filter block, with pore sizes in the range of 0.1 to 100 μm. These values correspond to the mean value of the pore sizes with normal distribution. Instead of the filter grist or the sinter blocks, filter membranes can also be used. In context of this invention, it is also possible to connect the two filtration segments together, so that, for example, the filter material is used in common in both the lines A and B. Preferably, the outlet of the second filtration segment leads the flow into the first filtration segment. The junction can be made in the region of the second half of the first filtration segment. The inner container for such a filter device is characterized in that it comprises of a first filter chamber, in which a second filter chamber is mounted, whereby each filter chamber is connected to the partial flows coming in from above, and a common main collection drain, built below the filter chambers, with pure water outlet for collection of the filtered water from the partial flows. The first filter chamber forms the filtration segment of the filter line A and the second filter chamber forms the filtration segment of the dilution line. A space-saving embodiment is possible through integration of the second filter chamber with the first filter chamber. The two partial flows are assigned to the two filter chambers and can be, if necessary, further subdivided into chamber segments or subchambers. At least one of the two filter chambers is preferably subdivided into at least two chamber segments, in which different filter materials are arranged. It is also possible to arrange the filter material in the main collection chamber and/or in the pure water outlet. It is thus possible to realize a common after-filter. Preferably, both filter chambers extend up to the collection chamber, which is located at the bottom wall of the inner container, whereby the first filter chamber forms an annular jacket encircling the second filter chamber. Thus a layout with rotation symmetry is achieved, which enables central, preferably upward, flow of the fluid in the filter line A and the dilution line B. This type of embodiment can be achieved cost-effectively even with a few components. To that end, preferably an annular drainage plate with filtrate orifices is arranged on the bottom wall of the inner container, which has radial collection channels on the side facing the bottom wall and a copular tray extending upwards from the drainage plate. Another embodiment comprises essentially of three components, placed within one another, and consist of an inner bowl, a filter bowl and an outer bowl. The pure water outlet from the collection chamber can be arranged on the side below the inner container. In order that the outflow of the pure water is at the upper side of the inner container, it is advantageous to build an ascending pipe within the inner container, which can preferably be a double-walled tube, through which a partial flow can also flow into one of the two filter chambers. The double-walled tube is built preferably in the lid and can be built between the copular tray or the inner and outer bowls and the lid. The outer tube of the double-walled tube can project into the first filter chamber or into a corresponding segment of the chamber of the first filter chamber. In this embodiment, the volume range of the first filter chamber of the second partial flow is also shared. In order to be able to deliver the water, a distributor device, which has, in a special embodiment, nozzles along the perimeter of the outer pipe, is mounted preferably at the lower end of the outer tube. The first filter chamber can be filled at least with ion exchanger resin, whereas the second filter chamber is filled, for example, with activated carbon. Exemplary embodiments of the invention are explained in detail below with the help of the following Figures. The Figures shown are: FIG. 1 A circuit diagram of a filter device with a filter line and a dilution line, FIG. 1 FIGS. 2 FIGS. 3 FIG. 4 Diagram showing the dilution portion in dependence of V, FIG. 5 Diagram corresponding to the FIG. 3 FIG. 6 Diagram showing dilution portion in dependence of the volume flow, FIG. 7 Schematic diagram showing a cross sectional view of the filter device, FIG. 8 A cross section of the filter device with the inserts, FIG. 9 A cross section of the filter device according to other layouts, FIG. 10 A cross section of the filter device according to the schematic diagram in FIG. 1 The resistance circuit diagram of the filter device 1 is shown in FIG. 1 The flow from both outlets of the filter line A and the dilution line B goes into the connection device 4, which is connected to the pure water outlet 5. The pressure decline in the filter device 1 between the branch points 6, 7 is marked with Δp. Δp is the value obtained by adding the values ΔpA1, ΔpA2, as well as ΔpB1, ΔpB2, which represent the corresponding pressure declines in the segments 10 The resistance circuit diagram of the filter device, according to an another embodiment, is displayed in FIG. 1 The pressure loss in the filter device 1 between the branching point 6 and the exit point 7′ is also denoted by Δp. Δp is the value obtained by adding the values ΔpA1 and ΔpA2 or ΔpB1 and ΔpB1, which denote the corresponding pressure declines in the segments 10 The pressure declines are functions of volume flow, as shown in the FIGS. 2 For VA<55 l/h, ΔpA2(VA)>ΔpA1(VA), that is, the filter characteristic of the first filtration segment 10 ΔpB and ΔpA resulting from both the functions are shown in FIGS. 3 The two curves shown in FIGS. 3 In FIG. 4, the dilution portions are shown in dependence of the volume flow. In the example shown here, the basic layout of the dilution portion of 50% is taken as the basis. Ideally, the dilution portion must, therefore, be constant for 0.5 over the entire shown volume flow range, and should give a straight line, as it is the case with the “ideal 50%” curve. The actual “Real Basic 50%” curve shows a slight deviation of about 4% from this ideal curve for the volume flow values less than 50 l/h, which is clearly better than the corresponding dilution curves according to the current status of the technology (Current Technology Status Ideal 50%). By adjusting the dilution valve to a dilution portion of 30%, one obtains the curve (30% for basic layout 50%), which rises, for small volume flows, and shows deviation of about 30% from the ideal value 0.3. This deviation is still distinctly smaller than that in the case of currently employed technologies (Current Technology Status Ideal 30%), whereby, for small volume flows, deviations of the dilution portion greater than 50% appear. In FIG. 5, the curves ΔpA and ΔpB for the basic layout with 30% dilution portion are shown. The pressure loss function ΔpB shows a slight deviation from the ideal curve (Total B Ideal), which corresponds to the preset dilution portion of 30%. This leads—as shown in FIG. 6—to the dilution portion curve, which lies above the line 0.3 for large volume flows and lies below this ideal line for volume flows <50 l/h. The corresponding curve according to the current status of the technology (Current Technology Status Ideal 30%) shows significant increase for small volume flows. If the dilution valve is opened further, so that dilution portion of 50% is achieved, one obtains a curve, which lies below the ideal value of 0.5. Here, the corresponding curve shows a deviation to the higher side compared to that resulting from the current status of the technology, whereby the percentwise deviation is significantly larger compared to the design according to the invention. With the adjustment, according to the invention, of the flow characteristic of the dilution line B in the filter line A, the deviation can be maintained below ±5% even for low volume flows for at least a dilution portion X. In FIG. 7, a vertical sectional view of the filter device 1 is shown. In the upper region, the raw water inlet 2 is shown, which leads the flow into the separation device 3, which divides the inflowing raw water into two partial flows. The left partial flow flows through the flow channel segment 10 The first filter chamber 54 surrounds the second filter chamber 55, which forms the second filtration segment 20 In FIG. 8, a schematic vertical sectional view of a filter device 1 is shown, which is comprised of an inner container 50, in which, essentially the filtration segments 10 One partial flow flows through the flow channel segment 10 The first chamber 54 forms the inner space of the inner container 50 in the upper region, which is subdivided into an upper chamber segment 54 In FIG. 9, a vertical cross section of the filter device according an another embodiment is shown. In the upper part, a part of the filter head 8 can be seen, which comprises of the raw water inlet 2, the separation device 3, the dilution valve 20 This head 8 is mounted on the double-walled pipe 60 projecting above, which consists of an outer pipe 61 In the interior space, besides the double-walled pipe 60, essentially three components are present. The inner bowl 100 consists essentially of a cylindrical or conic wall 102, which tapers to the upside, and latches into the inner pipe 61 At the upper side it is encompassed by an outer bowl 120, which also comprises essentially of a cylindrical wall 122, which tapers on the upside, and latches onto the outer pipe 61 In FIG. 10, yet another embodiment of the filter device 1 is shown, which corresponds to the schematic diagram of the FIG. 1 A filter appliance including a dilution device, wherein the diluted portion remains largely constant when the entire volume flow is modified. Said filter device is characterized in that the flow characteristic-defined by the pressure loss function Deltap<SUB>B</SUB>({dot over (V<SUB>B</SUB>)-of the constituents of the dilution line B is adapted to the flow characteristic defined by the pressure loss function Deltap<SUB>A</SUB>({dot over (V<SUB>A</SUB>)-of the constituents of the filter line A, in such a way that the dilution condition holds good for at least one diluted portion X where X={dot over (V<SUB>B</SUB>/{dot over (V<SUB>A</SUB>+{dot over (V<SUB>B </SUB>for volume flows between be {dot over (V<SUB>1</SUB>=10 liters per hour and {dot over (V<SUB>2</SUB>=120 liters per hour, first volume flow range, for at least one second volume flow range of at least 5 liters per hour inside the first volume flow range, Deltap<SUB>A</SUB>({dot over (V<SUB>A</SUB>) designating the pressure drop over the dilution line B according to the respective volume flows {dot over (V<SUB>A</SUB>, {dot over (V<SUB>B </SUB>in liters/min of the water in lines A and B. Method for producing a filter appliance (1) for purifying and/or at least partly dealkalising untreated water, with an untreated water inlet (2) and a treated water outlet (5), with a filter section A comprising a flow channel portion (10a) and a first filtration portion (10b) and with a blending section B comprising an adjustable blending valve (20a) and a second filtration portion (20b), which sections are connected via a separating device (3) to the untreated water inlet (2) and via a connecting device (4) to the treated water outlet (5),
wherein the two filtration portions (10b, 20b) are disposed in an inner vessel, characterised inthat the flow characteristic, defined by a pressure loss function ΔpB(V̇B), of the components of the blending section B is adapted to the flow characteristic, defined by a pressure loss function ΔpA(V̇A), of the components of the filter section A such that there applies to at least one blending proportion X0, set by means of the blending valve, with X0 = V̇B/(V̇A+V̇B) for volumetric flow rates between V̇1= 10 to V̇2 = 120 l/h (first volumetric flow rate range) for at least one second volumetric flow rate range with a range of at least 5 l/h within the first volumetric flow rate range, the blending condition: V˙B1-xx-V˙AV˙A≤0.15=G
wherein G denotes the limit value of the blending condition, X the blending proportion set in accordance with the volumetric flow rate V̇A+V̇B, ΔpA.(V̇A) the pressure drop across the filter section A and ΔpB(V̇B) the pressure drop across the blending section B, in each case in accordance with the volumetric flow rates V̇A, V̇B in [1/min] of the water in the sections A and B,
and that the flow surface areas QA and QB, in each case in m2, and the distances hA and hB, in each case in m, of the first and the second filtration portion (10b, 20b) are dimensioned such that DA=X01-X0DB
applies to the pressure loss factors DA and DB, in each case in kPah/m3, of the two filtration portions (10b, 20b),
wherein DA=∫0hASAhQAhdhDB=∫0hBSBhQBhdh and SA(h) and SB(h), in each case in kPah/m2, are the pressure loss coefficients of the filter materials and QA and hA as well as QB and hB denote the flow surface areas and distances of the filter sections A and B through which water has flowed. Method according to Claim 1, characterised in that the blending valve (20a) and the second filtration portion (20b) are dimensioned such that ΔpB1(V̇B)<ΔpB2(V̇B), wherein ΔpB1(V̇B) is the pressure loss function of the blending valve (20a) and ΔpB2(V̇B) is the pressure loss function of the second filtration portion (20b), applies in the second volumetric flow rate range. Method according to Claim 1 or 2, characterised in that the blending valve (20a) is completely open, wherein the blending valve (20a) has a flow characteristic ΔpB1(V̇B),
that the flow characteristic ΔpA1(V̇A) of the flow channel portion (10a) is adapted to the flow characteristic ΔpB1(V̇B), and
that the pressure loss functions ΔpA2(V̇A) and ΔpB2(V̇B) of the first and the second filtration portions (10b, 20b) are adapted to one another, wherein the adaptation depends on the set blending proportion X0. Filter appliance (1) for purifying and/or at least partly dealkalising untreated water, with an untreated water inlet (2) and a treated water outlet (5), with a filter section A comprising a flow channel portion (10a) and a first filtration portion (10b) and with a blending section B comprising an adjustable blending valve (20a) and a second filtration portion (20b), which two sections are connected via a separating device (3) to the untreated water inlet (2) and via a connecting device (4) to the treated water outlet (5),
wherein the two filtration portions are disposed in an inner vessel comprising a first filter chamber (54) in which a second filter chamber (55) is disposed, wherein each filter chamber (54, 55) is connected to a partial flow supplied by the separating device (3) at the top, and a common collecting chamber (57) with the treated water outlet (5) for collecting the filtered partial flows is disposed below the two filter chambers (54, 55), characterised in that QA lies in the range from 0.0005 m2 to 0.06 m2 and QB in the range from 0.0001 m2 to 0.03 m2, wherein QA denotes the flow surface area of the filter section A and QB the flow surface area of the filter section B, and
that QA and QB, in each case in m2, and the distances hA and hB of the sections A and B through which water has flowed, in each case in m, of the first and the second filtration portion (10b, 20b) are dimensioned such that DA=X01-X0DB
wherein DA=∫0hASAhQAhdhDB=∫0hBSBhQBhdh and SA(h) and SB(h), in each case in kPah/m2, denote the pressure loss coefficients of the filter materials and X0 denotes a blending proportion set by means of the blending valve with X0 = V̇B/(V̇A+V̇B) with the volumetric flow rates V̇A, V̇B in [1/min] in the filter sections A and B, applies to the pressure loss factors DA and DB, in each case in kPah/m3, of the two filtration portions (10b, 20b). Filter appliance according to Claim 4, characterised in that the filter material of the filter section (s) A and/or B is a filter bed with an average grain size in the range from 0.1 to 2 mm. Filter appliance according to Claim 4, characterised in that the filter material of the filter section(s) A and/or B is a filter block with average pore sizes in the range from 0.1 to 100 µm. Filter appliance according to any one of Claims 4 to 6, characterised in that the outlet of the second filtration portion (20b) opens into the first filtration portion (10b). Filter appliance according to Claim 7, characterised in that the outlet of the second filtration portion (20b) opens out in the region of the second half of the first filtration portion (10b). Filter appliance according to any one of Claims 4 to 8, characterised in that at least one of the two filter chambers (54, 55) is divided into at least two chamber portions (54a, 54b) in which different filter materials are disposed. Filter appliance according to any one of Claims 4 to 9, characterised in that filter material is disposed in the collecting chamber (57) and/or in the treated water outlet (5). Filter appliance according to any one of Claims 4 to 10, characterised in that the two filter chambers (54, 55) extend up to the collecting chamber (57), wherein the first filter chamber (54) encloses the second filter chamber (55) in the shape of a ring. Filter appliance according to any one of Claims 4 to 11, characterised in that a ring-shaped drainage plate (71) with filtrate openings (72) is disposed on the bottom wall (52) of the inner vessel (50), which plate comprises, on the side which faces the bottom wall (52), radially extending collecting channels (73) and a cup-shaped insert (70) extending upwards from the drainage plate (71). Filter appliance according to Claim 12, characterised in that the inner vessel (50) comprises a cover (53) in which a double-walled pipe (60) is disposed. Filter appliance according to Claim 13, characterised in that the outer pipe (61a) of the double-walled pipe (60) projects into the first filter chamber (54). Filter appliance according to Claim 14, characterised in that the outer pipe (61a) comprises, in the region of the first filter chamber (54), a distributor device (63) for discharging the supplied water. Filter appliance according to Claim 15, characterised in that the distributor device (63) comprises nozzles (62) distributed over the circumference of the outer pipe (61a). Filter appliance according to any one of Claims 4 to 16, characterised in that the first filter chamber (54) at least is filled with ion exchange resin. Filter appliance according to any one of Claims 4 to 17, characterised in that the second filter chamber (55) at least is filled with activated carbon.REFERENCE SYMBOLS