WO2009013072A1

WO2009013072A1 - Method and device for indirectly measuring the depletion of the filtering material of a filter

Info

Publication number: WO2009013072A1
Application number: PCT/EP2008/057531
Authority: WO
Inventors: Roger Prokasky
Original assignee: Brita Gmbh
Priority date: 2007-07-21
Filing date: 2008-06-16
Publication date: 2009-01-29
Also published as: CL2008002134A1; DE102007034158B9; DE102007034158B4; AR067593A1; DE102007034158A1

Abstract

A description is given of a device (1) for measuring the depletion of the filtering material of a filter (3), wherein the depletion occurs after a maximum volume Vm of liquid has flowed through. The device comprises a measuring cell (20) through which the liquid can flow, a rod-shaped measuring head (6), which has an outer circumferential surface (8) and is arranged perpendicularly in relation to the direction of flow of the liquid in the measuring cell (20), wherein at least two pressure measuring channels (12, 14, 16) are arranged in the measuring head (6) and open out into measuring openings (13, 15, 17) in the outer circumferential surface (8) of the measuring head (6). Also provided are a pressure measuring device (40), which is connected to the measuring channels (12, 14, 16), and an evaluation device (30), which is electrically connected to the pressure measuring device (40) and is designed for determining the volume V of the liquid from the pressure measuring signals, over a time period t beginning from a point in time t0 at which the filter (3) is put into operation, and for comparing the volume V with the maximum volume Vm. Also provided is a display device (32), which is electrically connected to the evaluation device (30). A method for indirectly measuring the depletion of a filtering material of a filter is also described.

Description

Method and device for the indirect measurement of the exhaustion of the filter medium of a filter

description

The invention relates to a device for the indirect measurement of the exhaustion of the filter medium of a filter, wherein the exhaustion occurs after the passage of a maximum volume V _{m of} a liquid. The invention also relates to a method for measuring the exhaustion of a filter means of a filter according to the preamble of claim 25.

A filter is understood in particular also filter cartridges.

Devices for the treatment of water have a filter into which a raw water flows and flows out of the filter filtered water. The filters or filter cartridges are filled with filter medium which removes pollutants from the raw water by way of adsorption and / or absorption. Typical filter media for drinking water are in granular form and are used for chemical and / or mechanical removal and / or reduction of organic and / or inorganic impurities.

The filter capacity of the filter medium is exhausted after the flow of a certain amount of raw water, ie a maximum volume V _m , so that the filter cartridge must be replaced. In order to ensure a consistently high quality of the filtered water, it is necessary to indicate to the user this exhaustion of the filter medium on the filter device, so that he makes the necessary replacement of the filter. So far, the following concepts have been pursued.

In gravitation-driven filter devices, a time measurement is performed, as described for example in DE 198 19 098 A1. This method has the disadvantage that in the measured period no conclusions about the actual amounts of water that have passed through the filter are possible. The capacity of the filter medium can therefore already be exhausted before the expiry of the relevant period of time, so that under certain circumstances no effective filtration can be carried out until the end of the period. This is not noticed by the user.

Another approach based on conductivity measurements of the water to be filtered is described in DE 10 2005 035 045 A1.

The object of the invention is to provide a device for the indirect measurement of the exhaustion of a filter medium of filters, which is simple and compact, allows the most accurate detection of the amount of water, is reliable and subject to no wear. The object also relates to the provision of a corresponding measuring method.

This object is achieved by a device for the indirect measurement of the exhaustion of the filter medium of a filter, which is characterized by a measuring cell through which the liquid can flow, a rod-shaped measuring head having a lateral surface which is arranged perpendicular to the flow direction of the liquid in the measuring cell Measuring head are arranged at least two pressure measuring channels, which open into measuring openings in the lateral surface of the measuring head, a pressure measuring device which is connected to the measuring channels, an evaluation device which is electrically connected to the pressure measuring device, and for determining the volume V of Liquid from the pressure measurement signals starting from a time t ₀ , at which the filter is put into operation, over a period of time t and for comparing the volume V with the maximum volume V _{m is} formed and a display device which is electrically connected to the evaluation device.

The device and method are based on the principle of the so-called Prandtl probe, which is a combination of pitot tube and static pressure probe. The Prandtlrohr, which extends parallel to the flow direction, has upstream of its tube tip a measuring port for measuring the total pressure PQ and annular at a distance from the pipe tip lateral holes for the static pressure measurement Ps.

According to the law of Bernoulli, the difference between the two pressures PG and Ps corresponds to the back pressure or dynamic pressure P ₀ :

p _ p _ p - E. _v ²

where p denotes the density of the liquid and v the flow velocity, which can also be provided with a correction factor depending on the installation position of the measuring device. It follows:

The volume flow Q is calculated with the flow cross-section A.

- A -

from which the volume V over a period t starting from a time t ₀ is calculated as follows:

A rod-shaped measuring head, which is arranged perpendicular to the flow direction of the liquid is compact and does not require within the flow cross-section own holding device, which may affect the flow adversely. A rod has the advantage that it has a continuous constant cross section, so that the receiving opening in the measuring cell can be adapted to the cross section and a simple assembly can be achieved by inserting the measuring head into the measuring cell. A rod-shaped measuring head is both manufacturing technology advantageous and easy to install.

The pressure measuring channels can be produced in a simple manner, for example by drilling, in the measurement head consisting of solid material.

The rod can for example be made of an extruded profile of plastic or metal, wherein over the length of the rod, an adaptation to the relevant flow cross section into which the rod is inserted, can be made.

Preferably, the rod-shaped measuring head extends through the entire cross section of the measuring cell. The flow cross section is thereby divided into two equal area sections. The measuring cell is preferably formed by a support tube, the z. B. can be installed in a water pipe. Such a support tube is therefore provided with corresponding connection means.

For insertion of the rod-shaped measuring head, the support tube has a corresponding, preferably adapted to the cross section of the measuring head, receiving opening.

The carrier tube may have a mounting platform, which preferably has fastening means for the measuring head. For this purpose, it is advantageous if the measuring head is attached to a base body which rests upon insertion of the measuring head on the mounting platform and can be fixed there.

The main body is also preferably designed for receiving the pressure measuring device.

Preferably, at least two measuring openings are arranged at an angle of 90 ° in the lateral surface of the rod-shaped measuring head.

It has been shown that with an exact mounting of the measuring head in the measuring cell two measuring openings and thus two pressure measuring channels are sufficient. A first pressure measuring channel opens on the inflow side into the lateral surface and serves to measure the total pressure PQ. A second measuring opening lying in the same cross-sectional plane, which is arranged offset by 90 ° from the measuring opening of the first pressure measuring channel, is provided for the measurement of the static pressure Ps.

In order to improve the accuracy of the measurement of the static pressure Ps, a further second measuring opening may be provided on the opposite side of the second measuring opening in the lateral surface, which is also arranged at an angle of 90 ° to the first measuring opening. Any installation tolerances of the rod-shaped measuring head or the receiving opening can be taken into account in this way by measurement.

A rod has the further advantage that it can be given a streamlined profile in a simple manner, so that the volume flow to be measured can be measured with little pressure loss.

Preferably, the rod-shaped measuring head has a cylindrical cross-section.

Further advantageous embodiments relate to a drop-shaped cross section, an oval cross section or an elliptical cross section.

In the case of the oval or elliptical cross sections, the first measuring opening is arranged in the vertex of the strongly curved peripheral section and a second measuring opening is arranged in the vertex of the slightly curved peripheral section of the rod-shaped measuring head.

The pressure measuring device may be a differential pressure measuring device, wherein the difference of the two pressures in the first and second pressure measuring channels is determined.

According to one alternative, the pressure measuring device may also comprise at least two pressure measuring sensors, which are also arranged at the outlet of the pressure measuring channels.

The evaluation device can be arranged on or in the main body. However, the evaluation device can also be arranged spatially remote from the body and be connected via cable, radio or the like with the pressure measuring device.

The display device and the evaluation device can form an integrated device. It is thereby possible to read the measurement result directly at the evaluation device.

If, for reasons of installation technology, it is not possible to accommodate the display device and the evaluation device in one place, the display device can also be arranged remotely from the evaluation device and be connected to the evaluation device via cable, radio or the like.

In front of the measuring cell may preferably be arranged a guide body. This guide body has the task to equalize the flow of liquid. Turbulence or the like is dissolved by the guide body, whereby the measurement result is improved.

The method for the indirect measurement of the exhaustion of a filter means of a filter, wherein the exhaustion occurs after flowing through a maximum flow V _{m of} the liquid is characterized in that according to the principle of a Prandtl probe the volume flow Q of the liquid is measured that from the volume flow Q starting from a time to, in which the filter is put into operation, determined over the time t, the volume V of the liquid and the volume V is continuously compared with the maximum volume V _m and the latest when reaching the maximum volume V _m, the comparison result is displayed. For determining the volume flow Q, the static pressure Ps is preferably measured at at least two measuring points. These two measuring points are formed by the two second measuring openings.

When the maximum volume V _m is reached, the result of the comparison is visually and / or acoustically displayed.

It is also possible to bring the respective residual volume to the display until the maximum volume is reached.

Exemplary embodiments of the invention are explained below with reference to the drawings. Show it:

FIG. 1 shows a measuring device installed in a water line,

FIG. 2 shows a perspective view of the measuring device,

FIG. 3 shows an exploded view of the measuring device,

FIG. 4 shows a side view of the measuring device,

FIG. 5 shows a section through that shown in FIG

Measuring device along the direction V-V,

FIG. 6 shows a side view of the measuring device according to a further embodiment,

FIG. 7 shows a section through that shown in FIG

Measuring device along the line VII-VII, FIG. 8 shows a section through the measuring head of FIG. 5 along the line VIII-VIII,

Figures 9 and 10 sections through a measuring head according to two further embodiments.

In the figure 1, a water pipe 2 is shown, in which a measuring device 1 and a filter 3 are installed in the form of a filter cartridge. The water pipe 2 has two pipe sections 2a, 2b, between which a support tube 22 is arranged, which includes a measuring cell 20. On the support tube 22, a base body 4 can be seen, on which a measuring head 6 is arranged, which projects into the support tube 22. The measuring head 6 can not be seen in FIG. On the base body 4 is the evaluation device 30, which is combined with a display device 32.

Between the pipe sections 2b and 2c of the filter 3 is installed, which has a filter means not shown. The water flowing in through the pipe section 2b is treated in the filter and leaves the filter 3 as filtered water through the pipe section 2c. The direction of flow is indicated by the arrow. The measuring device 1 is thus connected upstream of the filter 3 and determines the volume V of the liquid flowing through the filter.

FIG. 2 shows a perspective view of the measuring device 1 from FIG. The support tube 22 is formed in the central part cuboid and includes there the measuring cell 20. Further, the support tube 22 has a coupling ring 27 and an external thread 26 for installation in the water pipe. The display device 32 comprises a display 33 on which, for example, the residual volume or the reaching of the maximum volume V _m can be displayed. In the figure 3 is an exploded view of the measuring device 1 can be seen. The support tube 22 has at the inlet end a guide body 25 which consists of a cross-shaped web structure in order to even out the flow of the liquid. The cuboid Mitttelteil the support tube 22 is formed on its upper side as a mounting platform 23. In the middle, an oval receiving opening 24 is provided, which is surrounded by an annular groove 29. Furthermore, in the mounting platform 23 a total of four threaded holes 28th

The actual measuring device 5 has the main body 4 with the measuring head 6, which is designed as a rod. This measuring device 5 is inserted with the measuring head 6 in the receiving opening 24 of the support tube 22 until the bottom of the base body 4 rests on the top of the mounting platform 23.

The main body 4 accommodates the pressure measuring device 40, which communicates with the pressure measuring channels located in the interior of the measuring head 6 (see FIG. 5). The pressure measuring channels, which can not be seen in FIG. 3, open into the measuring openings 13 and 15 in the lateral surface 8 of the measuring head 6. The details of the measuring head 6 are explained in more detail in the following figures.

In addition, the measuring device 1 comprises the evaluation device 30, which is electrically connected to the measuring device 5, in particular to the pressure measuring device 40.

FIG. 4 shows a side view of the measuring device 1. It can be seen that the measuring head 6 extends within the measuring cell 20 through the entire flow cross section. The measuring head 6 divides the flow cross-section into the two halves with the cross-sectional areas A / 2. FIG. 5 shows a section through the measuring device 1 shown in FIG. 4 along the line VV. The measuring head 6 is located in the receiving opening 24, the inner dimensions of which are adapted to the outer contour of the measuring head 6. The measuring head 6 extends through the entire flow cross-section and projects into a recess 21 located inside the support tube 22. The end face 9 of the measuring head thus lies within the recess 21.

On the inflow side, the first measuring opening 13 is arranged, through which the pressure measuring channel 12 with the horizontal and vertical channel sections 12a, 12b opens into the lateral surface 8 of the measuring head 6. The measuring channel 12 is used to measure the total pressure PQ.

For measuring the static pressure Ps, a second pressure measuring channel 14 is provided, which also consists of a horizontal and a vertical channel section 14a, 14b. The channel section 14b opens via the measuring opening 15 (not shown) in the lateral surface 8 of the measuring head 6. The two channel sections 12a and 14a are arranged at right angles to each other.

Upwardly, the base body 4 connects, which is formed substantially rectangular and has an interior space 45 which is surrounded by the peripheral wall 44 and the bottom wall 43. In the interior 45 is the pressure measuring device 40 consisting of the two pressure measuring sensors 41 and 42 which are connected to the respective measuring channels 12 and 14. The main body 4 rests on the mounting platform 23 and is sealed by means of a sealing ring located in the annular groove 29.

FIGS. 6 and 7 show the illustrations corresponding to FIGS. 5 and 6 of a further embodiment. In contrast to FIGS. 4 and 5, the measuring head 6 does not extend completely. constantly through the flow cross section. The end face 9 is arranged at a distance from the tube inner wall of the carrier tube 22.

FIG. 8 shows the oval cross section along the line VIII-VIII of the measuring head 6 shown in FIG. The section lies in the plane of the horizontal channel sections 12a, 14a. It can be seen that the channel sections 12a, 14a and the corresponding measuring openings 13 and 15 are at a right angle to each other. The flow direction is indicated in this figure as well as in other figures by an arrow. The first measuring opening 13 is located at the apex 7a of the strongly curved peripheral section 8a, while the second measuring opening 15 is arranged at the apex 7b of the slightly curved peripheral section 8b.

FIG. 9 shows a further embodiment in which, opposite the second measuring opening 15, a further second measuring opening 17 with a corresponding channel section 16a of the pressure measuring channel 16 is arranged. Since the passage portion 16a opens into the passage portion 14a, the pressure sensing passage 16 in the embodiment consists only of the passage portion 16a. The two pressure measuring channels 14 and 16 both serve to measure the static pressure Ps, wherein from the pressure difference, an offset of the measuring head 6 can be detected within the measuring cell, which is due for example to tolerances. Via a corresponding correction factor, the flow velocity can be corrected accordingly.

FIG. 10 shows a further embodiment in which the cross-section is drop-shaped. LIST OF REFERENCE NUMBERS

measuring device

Water pipe a, b, c water pipe

filter

body

measuring device

Measuring head a, b vertex

Mantle surface a strongly curved Umfangsabschnittb slightly curved peripheral portion

End face 2 first pressure measuring channel 2a, b channel section 3 first measuring opening 4 second pressure measuring channel 4a, b channel section 5 second measuring opening 6 third pressure measuring channel 6a channel section 7 second measuring opening 0 measuring cell 1 recess 2 carrier tube 3 mounting platform 4 receiving opening 5 guide element 6 external thread About union ring

threaded hole

ring groove

seal

evaluation

display

Pressure measuring device

Pressure measuring sensor

bottom wall

peripheral wall

inner space

Claims

claims

1. Device (1) for measuring the exhaustion of the filter means of a filter (3), wherein the exhaustion after the passage of a maximum volume V _{m of} a liquid enters, characterized by

a measuring cell (20) through which the liquid can flow

a rod-shaped, a lateral surface (8) having a measuring head (6) which is arranged perpendicular to the flow direction of the liquid in the measuring cell (20),

wherein in the measuring head (6) at least two pressure measuring channels (12, 14, 16) are arranged, which open into measuring openings (13, 15, 17) in the lateral surface (8) of the measuring head (6),

a pressure measuring device (40) which is connected to the measuring channels (12, 14, 16),

- An evaluation device (30), which is electrically connected to the pressure measuring device (40), and for determining the volume V of the liquid from the pressure measuring signals starting from a time t ₀ , at which the filter (3) is put into operation over a time period t and for comparing the volume V with the maximum volume V _{m is} formed and

a display device (32) which is electrically connected to the evaluation device (30).

2. Apparatus according to claim 1, characterized in that the rod-shaped measuring head (6) in the measuring cell (20) can be inserted.

3. Apparatus according to claim 1 or 2, characterized in that the measuring cell (20) has a receiving opening (24), wherein the opening cross section of the receiving opening (24) is adapted to the cross section of the rod-shaped measuring head (6).

4. Device according to one of claims 1 to 3, characterized in that extending the rod-shaped measuring head (2) through the entire cross section of the measuring cell (20).

5. Device according to one of claims 1 to 4, characterized in that the measuring cell (20) is a support tube (22).

6. Apparatus according to claim 5, characterized in that the carrier tube (22) has a mounting platform (23).

7. Device according to one of claims 1 to 6, characterized in that in the lateral surface (8) of the measuring head (6) at least two measuring openings (13, 15; 13, 17) are arranged at an angle of less than 90 °.

8. Device according to one of claims 1 to 7, characterized in that a first measuring opening (13) is arranged upstream.

9. Apparatus according to claim 8, characterized in that two second measuring openings (15, 17) are arranged opposite one another and in each case form an angle of 90 ° with the inflow-side first measuring opening (13).

10.Vorrichtung according to one of claims 1 to 9, characterized in that the rod-shaped measuring head (6) has a cylindrical cross-section.

11.Vorrichtung according to one of claims 1 to 9, characterized in that the rod-shaped measuring head (6) has a teardrop-shaped cross-section.

12. Device according to one of claims 1 to 9, characterized in that the rod-shaped measuring head (6) has an oval cross-section.

13. Device according to one of claims 1 to 9, characterized in that the measuring head (6) has an elliptical cross-section.

14. Device according to one of claims 12 or 13, characterized in that the first measuring opening (13) in the vertex (7a) of the strongly curved peripheral portion (8a) and at least one second measuring opening (15, 17) in the vertex (7b) of the weak curved peripheral portion (8b) of the rod-shaped measuring head (6) is arranged

15. Device according to one of claims 1 to 14, characterized in that the pressure measuring device (40) is a differential pressure measuring device.

16. Device according to one of claims 1 to 14, characterized in that the pressure measuring device (40) comprises at least two pressure measuring sensors (41, 42) which are each arranged at the output of the pressure measuring channels (12, 14, 16).

17. Device according to one of claims 1 to 16, characterized in that the measuring head (6) on a base body (4) is arranged.

18. Device according to one of claims 1 to 17, characterized in that the base body (4) receives a pressure measuring device (40).

19. Device according to one of claims 1 to 18, characterized in that the base body (4) on the mounting platform (23) is fixable.

20. Device according to one of claims 1 to 19, characterized in that the evaluation device (30) is arranged on or in the base body (10).

21.Vorrichtung according to one of claims 1 to 19, characterized in that the evaluation device (30) is arranged away from the main body (10) and is connected via cable or radio to the pressure measuring device (40)

22. Device according to one of claims 1 to 21, characterized in that the display device (32) and the evaluation device (30) form an integrated device.

23. Device according to one of claims 1 to 22, characterized in that the display device (32) remote from the evaluation device (30) is arranged and connected by cable or radio to the evaluation device (30).

24. Device according to one of claims 1 to 23, characterized in that in front of the measuring cell (20) a guide body (50) is arranged.

25. Method for the indirect measurement of the exhaustion of a filter medium of a filter, wherein the exhaustion occurs after flowing through a maximum flow V _{m of} the fluid, characterized

according to the principle of a Prandtl probe, the volume flow Q of the liquid is measured,

starting from the volume flow Q starting from a time to at which the filter is put into operation, the volume V of the fluid is determined over the time span t and the volume V is continuously compared with the maximum volume V _m and

that at the latest when reaching the maximum volume V _m, the comparison result is displayed.

26. The method according to claim 25, characterized in that for determining the volume flow Q of the static pressure P _{s is} measured at at least two measuring points.

27. The method according to any one of claims 25 or 26, characterized in that the achievement of the maximum volume V _{m is} visually and / or acoustically displayed.

28. The method according to any one of claims 25 to 27, characterized in that until reaching the maximum volume V _m, the respective residual volume is displayed.