DE1255085B - Filters for liquids that contain fine solid particles in suspension - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

BOId

German class: 12d-27

Number: 1255 085

File number: L 46141VII b / 12 d

Filing date: October 23, 1963

Open date: November 30, 1967

The invention relates to a filter for liquids containing fine solid particles in suspension, for example for wastewater from paper production, in which the liquid to be filtered is in a chamber formed from essentially perpendicular filter walls is introduced and in the one Cleaning device for these walls is arranged outside the chamber, which extends parallel to the fixed chamber walls moved.

There are known filter devices in which a movable or stationary cleaning device is used Row of nozzles is used, by means of which a flushing liquid is sprayed against the filter walls. A major disadvantage of the known filter devices is that for cleaning the filter the filtration process must be interrupted. That is, the liquid in the filter must drained, and the inlet openings must be closed before the cleaning process can use. The liquid to be filtered can only be let in again after cleaning has taken place. and the filtering process can begin again.

In contrast, the operation of the device according to the present invention is not intermittently, but this device works continuously.

This is achieved according to the invention by the fact that the arranged outside on the filtrate side of the chamber movable cleaning device has nozzles, through the flushing liquid against the filter walls the chamber and channels below the walls for separate collection of the clear filtrate and the cloudy rinsing liquid are arranged with the prefiltrate, with deflecting surfaces forming the filtrate channels at least temporarily cover and inside the chamber a lower drain to discharge the heavy particles as well as the thickened slurry is provided.

The invention is described on the basis of the exemplary embodiments. It shows

F i g. 1 schematically shows an axial section through a first embodiment of the subject matter of the invention,

F i g. 2 shows a section along the line II-II in FIG. 1,

3 shows a development of the filter wall according to FIG. 1,

Fig. 4 shows a section through the filter wall according to the line IV-IV in Fig. 3,

F i g. 5 is a partial view of the deflecting surfaces;

F i g. 6 or 7 each an enlarged representation of horizontal sections through the cleaning device,

Filter for liquids that contain fine solid particles in
Suspension included

Applicant:

Societe dite: E. & M. Lamort FiIs,

Vitry-le-Francois, Marne (France)

Representative:

Dr. H. Feder, patent attorney,

Düsseldorf, Pempelforter Str. 18

Named as inventor:

Pierre Louis Emile Marie Lamort,

Vitry-le-Francois, Marne (France)

8 shows an enlarged section through another embodiment of the cleaning device,

F i g. 9 is a plan view of the FIG. 8 part of the cleaning device shown,

Fig. 10 is a vertical section through another Embodiment of a device according to the invention,

FIG. 11 is a side view of that shown in FIG Device and

12 shows a section on an enlarged scale through part of the device according to FIG. 10.

In the case of the FIGS. The device shown in FIGS. 1 to 7 are two cylinders 1 which are concentric with one another and 2 arranged with a vertical axis on a base plate 3 such that between the cylinders annular chamber 4 is formed. On the outside of the filter walls 1 and 2 there are metal frames 5 and 6 are provided, which carry a filter cloth made of metal mesh, for example. The frames 5 and 6 are made of horizontal bars 8 and vertical bars 7, the thickness of the horizontal bars is significantly less than the thickness of the vertical bars and the tops of the bars 7 beveled are.

The base plate 3 forms the bottom of the chamber 4 and has annular channels 9, 10, 11 and 12 on both sides of this chamber.

709 690/448

The channels 9 and 12 can through a common system of drainage pipes 13 and the channels 10 and 11 can be emptied through a common system of pipes 14.

The liquid to be filtered is fed into the chamber 4 through a pipe 15 in the middle of the chamber 4 introduced, with a helical distributor device 16, the liquid in the chamber evenly distributed. The chamber 4 also has two outlets, namely a drain 17 in the lower part and in the upper part a drain 18 for the discharge of the light particles.

A vertical shaft 19 carries arms 20 and 21 which in turn support the pipes 22 and 23 of the flushing device wear, which are provided over the entire height of the filter spiral and 2 with spray openings. This arm and the flushing device form the moving part, which is driven by a motor 24 with adjustable speed around the shaft 19 rotates.

The shaft 19 itself is hollow at least in its upper part and is connected to the flushing pipes 22 and 23 by pipes 25 and 25 α . A rotatable connection 26 allows the flushing devices 22 and 23 to be supplied with a pressure fluid while the movable part of the device is rotating.

The purging pipes 22 and 23 carry by means of a not shown in the drawing, each connecting a deflector 27 and 28. These baffles thus move together with the rinsing device and cover the channels 10 and 11 through an adjustable angle range a, in the sense of movement behind the Flush pipes 22 and 23 is from (Fig. 5). In order to be able to change the angle α , there are deflecting surfaces 27 and 28, as in FIG. 5 shown for the deflecting surface 27, each consisting of two mutually displaceable parts 27 a and 27 b.

The frames 5 and 6, which carry the filter cloths 1 and 2, respectively, have drip edges at their lower end 29 under which the baffles 27 and 28 move.

The flushing devices 22 and 23 consist, as shown in FIGS. 6 and 7 is shown, each from a tube 30 to which the nozzles 31 are attached. These nozzles are designed and arranged so that the Hydraulic fluid emerges from them in the form of a fan-shaped jet, with the various Connect the jets to one another in such a way that a total of an uninterrupted liquid band is created. the Nozzles 31 are suitably self-cleaning nozzles, and each nozzle is subject to movement an inner piston 32 thereby self-cleaning that in the event of a sudden drop in the fluid pressure a retraction of the piston 32 occurs, whereby the outlet opening 33 is enlarged and is cleaned in the process. Such flushing devices are known per se in the paper industry.

The movable arm 20 carries a cam 20 a, which closes a contact 34 with each revolution, the brief closure of the valve 35 a, which is in the supply line 35, which the flushing devices 22 and 23 dines, lies. In this way, with every revolution of the moving part, the nozzles become the Device cleaned once.

The tubes 22 and 23 of the flushing device are not parallel to the cylinder walls 1 and 2, but rather form an angle b with them (FIG. 1), the meaning of which will be explained below. The nozzles 31 are not equally spaced from one another, but are arranged on the tubes 30 in such a way that the fan-shaped liquid jets on the cylinder walls 1 and 2 adjoin one another without any gaps.

The device according to the invention works as follows:

The liquid to be filtered is through the pipe

15 introduced into chamber 4. The guiding device

16 gives the liquid a slight rotating movement, due to which it moves evenly in the chamber 4 distributed so that the formation of dead water areas is prevented. The liquid passes through the filter walls 1 and 2, which are supported by the frames 5 and 6, trickles through to the Outer sides of the walls 1 and 2 descend and drip into the channels 10 and 11, which are located on the base plate 3 are located below walls 1 and 2.

A part of the solid particles suspended in the liquid becomes when passing through the filter walls 1 and 2 held back and forms a layer on the inside of these walls with increasing Thickness. This layer very quickly forms a filter element that is much finer and more effective than that Walls 1 and 2 themselves, which only serve as a carrier for this filter layer. The longer the filtration continued becomes, the clearer the filtrate becomes, but the more the penetration through the filter surfaces increases Amount from. Without the flushing devices 22 and 23, the amount filtered would very quickly up to one Volume that is almost zero decrease. As a result of the regular rotation of the flushing device each surface line of cylinders 1 and 2 is periodically subjected to the action of the liquid jets, which emerge from the nozzles 31. These jets of liquid penetrate the filter walls 1 and 2 of outwards inwards, which causes a cleaning of the walls in countercurrent and the filter layer, which is has formed on the insides, destroyed.

In this way, the flushing devices 22, 23 begin along a surface line after each passage the filtering process all over again. Immediately after passing the flushing devices 22, 23 in front of a Surface line, the emerging filtrate is cloudy until the filter layer has formed again. This is insufficient Filtered cloudy filtrate (Vorfiitrat) trickles along the vertical walls 1 and 2 together with the rinsing liquid down and falls on the deflection surfaces 27 and 28, through which it in the channels 9 and 12, from which it is derived through the pipeline 13.

This cloudy rinsing liquid is carried through with the prefiltrate except for a part which flows to the pump 36 the pipe 15 is fed back into the chamber 4 together with the pulp. After a certain Time during which the filtrate obtained has cleared sufficiently through the formation of the filter layer, give the deflection surfaces 27 and 28, which move evenly together with the cleaning device, the channels 10 and 11 free again, into which the clear filtrate then falls and from which it passes through the Pipes 14 is derived.

It is readily apparent that by changing the speed of the rinsing devices 22 and 23 and the angle a covered by the plates 27 and 28, the ratio of the prefiltrate to the clear filtrate can be adjusted so that a filtrate which is clarified at will can be obtained .

ίο

Those retained by the filter in chamber 4 Solid particles generally form three groups:

a) The heavy particles that settle on the bottom and pass through the pipe 17 continuously or can be discharged at regular intervals;

b) the light particles floating on the surface and discharged through the tube 18 can be;

c) the substances which have almost the same density as the liquid and which float in the liquid in indifferent equilibrium. These particles can be removed from the liquid due to the following phenomenon. The liquid jets of the flushing devices 22 and 23 bring air in the form of fine bubbles into the suspension in the chamber 4. These fine air bubbles have a tendency to deposit on these solid particles and carry them ^ao upwards, from where they are discharged through the pipe 18 can.

The flushing devices 22 and 23 are carried out by a pump 36 which generates a high pressure a part of the cloudy rinsing liquid with prefiltrate from the channels 9 and 12, which through the pipe 13 are derived, fed.

In this way the device is self-sufficient and there is no need for external liquid to feed. Since the flushing devices 22 and 23 are fed with a cloudy liquid it is necessary to use nozzles that clean themselves, as well as the device as described above, this cleaning is effected once with each rotation.

The jets of liquid from the flushing devices 22 and 23 have to overcome the static liquid pressure in the interior of the chamber 4 so that they can cause the filter walls 1 and 2 to be cleaned. This fluid pressure is not uniform, but increases from top to bottom. For this reason, the tubes 22 and 23 of the flushing device, on which the cleaning nozzles 31 are arranged, are slightly inclined towards the walls 1 and 2 (angle b), and the distances between the nozzles 31 are chosen so that the cleaning effect over the whole The height of the filter walls is uniform.

In order to obtain a very clear final filtrate, it is necessary to make the separation from the pre-filtrate as complete as possible. For this reason, the frames 5 and 6, the vertical rods 7 are provided, which are arranged so close to each other that the filter walls 1 and 2 are divided into relatively narrow vertical bands and so the filtrate between the rods is practically directed vertically downwards. This prevents the filtrate from trickling down, for example in helical paths, following the threads of the fabric that forms the walls, which could be the case if this were not prevented by the construction of the frames 5, 6, without the proper separation the filtrate would not be possible. For the same reason, the horizontal bars 8 are less thick than the bars Ί, and their upper edge is beveled. This is intended to prevent the filtrate from making its way in the horizontal direction along the rods 8.

In order to avoid mixing of the clear filtrate with the prefiltrate, the rinsing devices are used 11 and 23 are provided with a casing 37 through which the cloudy liquid can splash out from the side is prevented. As shown in FIG. 7, the jacket 37 is provided with four flexible lips 38, the distances between which are slightly larger than the distances between successive rods 7 and each of which bend when passing the rods 7.

Furthermore, if this is deemed necessary, there can be a dependency between the liquid level in the chamber 4 and the speed of rotation of the movable part of the device may be provided in such a way that the liquid level is kept constant if changes occur in the amount of fluid to be filtered.

Furthermore, in cases in which it is desired to obtain filtrates of different clarity, provision can be made to subdivide the annular channels further into additional channels 9 a and 9 b, which are between channels 9 and 10 or between channels 11 and 12 are arranged. The deflecting surfaces 27, 28 are then also composed of parts 27, 27 c, 27 d of different widths, as shown in FIG. By changing the length of the various parts 27 c and 27 d of the plates 27 and 28, the desired distribution of the various filtrates in the channels can easily be achieved.

The device according to the invention has the following advantages:

The principle of filtration through a layer that is formed from particles that are suspended in the turbidity is known per se. This principle is generally applied to devices in which the filter surface is carried by a drum rotating around a horizontal axis. In these well-known Devices is the movable filter surface and the cleaning device, in general a flushing device that works with an externally supplied liquid, fixedly arranged. Around To filter large amounts of liquid and to obtain a clear filtrate, a large filter surface is required, so that, in order to obtain devices with a large filter area, they quickly become very complicated and get heavy.

In contrast to these known arrangements is in the device according to the invention Filter surface firmly, which makes it possible to large without difficulty and at no high cost Surfaces, while on the other hand the filter walls can be supported by frames, so that no very high precision is required in the construction and the frames are handcrafted can be made. The base plate 3 can be made of concrete, which again Making large devices easier. The only moving part is the flushing device with the deflection surfaces connected to it, which are mechanically very simple and light and which also does not require high precision in manufacture, since it does not involve fixed parts must be connected. There are therefore no difficulties in these moving parts for Manufacture devices with large dimensions.

Maintenance and operation of the device according to the invention are very simple and easy, as a result the simplicity of the mechanical elements used. The cleaning of the device is also

easy to perform because it is completely open and to allow access to the interior of the chamber 4 and to the To facilitate attachment of the filter fabric, the frame 5 can be dismantled.

Thanks to the precautions taken in the construction of frames 5 and 6 and the shielding of the flushing devices 22 and 23, it is also easier to obtain a complete separation of the filtrates without that there is a possibility that prefiltrate gets into the clear filtrate, which is a necessary requirement for effective filtration.

In the foregoing, only exemplary embodiments are described with reference to the figures. The device according to the invention, however, can also be carried out in a manner other than that described. So can Devices constructed according to the same principle to achieve a very large filter surface, contain a plurality of chambers in the manner of the chamber 4, which are arranged concentrically with one another can that they are provided with a common mobile equipment for the flushing devices are.

It is also possible to construct the devices so that the filter walls are not in the form of Cylindrical surfaces are arranged, but in the form of mutually parallel, perpendicular planes, each of which two form a chamber that contains the liquid to be filtered, the cleaning device, the also stand vertically here, be guided back and forth along the planes of the filter walls. Such a one Apparatus is shown in Figs. In this device, too, filter walls 1 and 2, which are supported by frame 5, a chamber 4. There are flushing pipes 22 attached for cleaning and a first channel 10 for the clear filtrate and a second channel 9 for the cloudy rinsing liquid and the prefiltrate.

The in the F i g. 10 to 12 shown device differs from the device according to FIG the F i g. 1 to 7 in the following points:

a) The filter walls 1 and 2 are not cylindrical, but flat, and the chamber 4 has one rectangular plan;

b) the cleaning device does not rotate, but is attached to a carriage 40 which is on a Rail 41 runs back and forth;

c) the deflection surfaces 42 are fixed with respect to the movement of the cleaning device, but in their inclination arranged adjustable, and their inclination can be adjusted so that a Clear filtrate slowly flowing down the filter walls 1 and 2 into the first channel 10, on the other hand a rapidly flowing down prefiltrate and cloudy rinsing liquid is directed into the second channel 9 will.

In this case, the filtrates are separated as follows:

If the cleaning device has passed a point, prefiltrate is present and flows with it high speed together with the cloudy rinsing liquid. This liquid is through deflecting the baffles 42 into the channel 9. After a certain period of time, the prefiltrate becomes clear, and the amount decreases significantly. The baffles 42 give this filtrate that slowly trickling down, less distraction, d. that is, the clear filtrate drips off into channel 10, as in FIG F i g. 12 shown. The surfaces 42 make it possible in this way to remove the pre-filtrate from the clear filtrate separate.

The inclination of the surfaces 42, which can be changed by rotating about the axes 43, causes So in this case the separation of the filtrates, which can also depend on the inclination of the Areas 42 from the level of the liquid in the chamber 4 may be provided.

Claims (10)

Patent claims: 1. Filters for liquids that contain fine solid particles in suspension, for example for Wastewater from paper manufacturing, in which the liquid to be filtered is essentially in one of vertically standing filter walls formed chamber is introduced and in which a cleaning device for these walls is arranged outside the chamber, which moves parallel to the fixed chamber walls, thereby characterized in that the outside arranged on the filtrate side of the chamber movable Cleaning device has nozzles (31) through which the rinsing liquid against the filter walls (1, 2) the chamber (4) is injected and channels below the walls (1, 2) for separate reception the clear filtrate (11, 10) and the cloudy rinsing liquid with the prefiltrate (9, 12) are, with deflection surfaces (27, 28 and 42) the Cover the filtrate channels (11, 10) at least temporarily and a lower one inside the chamber (4) Drain (17) is provided to remove the heavy particles and the thickened sludge is. 2. Apparatus according to claim 1, characterized in that on the outer sides of the filter walls (1, 2) frames (S, 6) are provided, which consist of horizontal bars (8) and vertical bars (7), the thickness of the horizontal Bars is much less than the thickness of the vertical bars and the tops of the horizontal bars are beveled. 3. Apparatus according to claim 2, characterized in that the vertical rods (7) so are arranged close together so that the filtrate between the rods is practically vertical is directed downwards. 4. Device according to one of claims 1, 2 or 3, characterized in that the tubes So (22, 23) on which the cleaning nozzles (31) are arranged are slightly inclined against the walls (1, 2) and the distances between the nozzles a (31) are chosen so that the cleaning effect is uniform over the entire height of the filter walls is. 5. Apparatus according to claim 4, characterized ge ~ kenzeicb.net that each nozzle by the movement an inner piston is subject to self-cleaning. 6. Apparatus according to claim 5, characterized in that the nozzles at least for Part with the prefiltrate from the second channels (9, 12) are fed. 7. Device according to one of claims 1 to 6, characterized in that the to be filtered Liquid is supplied in the middle of the chamber via a distributor device (16) will. 8. Device according to one of claims 1 to 7, characterized in that the chamber (4) has an upper drain (18) for discharging the light particles. 9. Device according to one of claims 1 to 8, characterized in that the deflecting surfaces (27, 28) through which the cloudy rinsing liquid and the prefiltrate are directed into the channels (9, 12) move evenly with the cleaning device. 10. Device according to one of claims 1 to 8, characterized in that the deflecting surfaces (42) fixed with respect to the movement of the cleaning device, but its inclination IO are adjustable and their inclination can be adjusted so that a clear fiI flowing slowly down the filter walls (1, 2) entered the first channel (10), on the other hand, the rapidly flowing cloudy rinsing liquid or the prefiltrate into the second channel (9 ) is steered. Considered publications:
German Patent No. 935 424;
German interpretative document No. 1112046. Legacy Patents Considered:
German Patent No. 1163 292. For this purpose 2 sheets of drawings 709 690/448 11.67 © Bundesdruckerei Berlin