DE2241385C2 - Method and device for clarifying liquid - Google Patents

Description

The invention relates to a method and a device for clarifying contaminants Liquid as specified in the preamble of claims 1 and 11, respectively.

A corresponding method and a corresponding device are described in US Pat. No. 3,497,452.

When operating this known device, which has a first and a second filter chamber, to clarifying liquid passed through the first filter chamber until the primary filter located there has been used up and needs to be replaced. The filtering process is then interrupted and the am Primary filter removed filter cake from the filter partition. The one with the suspended Filter cake laden unclarified liquid is exposed to the high pressure in the first filter chamber and by a arranged in the second filter chamber Secondary filter put through again in circulation, with the filter cake suspension on the secondary filter is transmitted. The clarified liquid is transferred directly from the secondary filter to the high pressure side of the Primary filter returned, where they used to detach the filter cake from the primary filter can be. The filter cake accumulated on the secondary filter is detached from it and outwards applied.

The invention is based on the object, based on a method and a device of type mentioned at the beginning of the implementation of the filtration process and the application of the separated Make impurities so that the sewage plant

"5 i nt only very short breaks for the relocation of the Impurities can occur and the impurities themselves end up in a form that theirs immediate deposit permitted without further treatment.

The object set is achieved according to the invention by a method and a device such as characterized in claim 1 or in claim 11 are; advantageous refinements of the invention emerge from the subclaims.

With the help of the invention, the time in which the filters are used to purify unclarified liquid is reduced to one Brought maximum while, conversely, the time in which

the filters are made functional again on one Minimum is lowered. The primary filter, which is used to clarify contaminated liquid, is automatically activated cleaned to the required extent and charged with new filter material for continued operation. The used filter material is removed from the first filter container, collected and disposed of, while the primary filter resumes the filtration process. Those discharged from the second filter chamber In the final state, impurities take the form of more or less compacted balls on. their moisture content is determined by varying the heating for the conveyor in the Can be adjusted to a desired value connection to the second filter chamber. If necessary, leaves So a practically dry waste product is preserved, while the originally contaminated liquid can be recovered almost completely in the pure state by removing the in Dampffortn Share is brought to condensation.

In a device designed according to the invention contaminated liquid to be clarified is pushed through the primary filter in the first filter chamber. The filtering pressure can either be through an overpressure on the inlet side or through a vacuum can be obtained on the outlet side of the primary filter. In the process of pushing through Liquid through the primary filter will rise as a result of the increasing accumulation of filter cake on the The high pressure side of the primary filter is its flow resistance and thus the pressure drop across the primary filter on As soon as this pressure drop has reached a specifiable value. the filter medium of the primary filter is in a sense used up. the filtration process for the liquid to be clarified is interrupted and that Completed filter system, especially the Filtrate discharge on the low-pressure side of the primary filter ceases. Then that on the primary filter ceases accumulated filter cake detached from it, for example using brushes, and in the unclarified liquid is suspended in the first filter chamber. Then the content of the first Filter chamber into the one serving as a desludging room transferred to the second filter chamber, with the addition of filter material to the suspension from the detached filter cake in the uncleared liquid the formation of a filter medium on the high pressure side of the secondary filter in the second filter chamber can be accelerated. The suspended filter cake as well as the approx added feed auxiliaries deposited, the The process is continued until all solid particles are separated and the liquid is in clarified state escapes on the low-pressure side of the secondary filter. From there she becomes one part a precoat forming mixing chamber supplied and therein with an addition of filter material offset. The resulting mixture of liquid and filter material is then on the high pressure side of the Primary filter introduced into the first filter chamber and leads there to accelerated formation of a filter medium on the primary filter: as soon as this is done, the filtering process is interrupted for the clarifying liquid resumed at the primary filter. During this filtering process, the The secondary filter in the second filter chamber frees the filter cake that has accumulated on it The bottom of the second filter chamber settles. The used filter cake is passed through a sludge as a sludge central screw at the solids outlet of the second filter chamber transported to a horizontal screw, which delivers it to a vertical snail. This vertical screw is surrounded by a heating jacket and thus enables the filler cake sludge to be heated up, thereby increasing it to a desired level Solidified consistency. At the same time, the vertical screw recycles the sludge that has solidified in this way

ίο outside in a waste bin, taking the heater of the sludge in the screw facilitates the spreading of the sludge.

In the drawing, the invention is based on a preferred embodiment for a according to the invention trained device for clarifying contaminated liquids illustrated: here shows

Fig. I is a perspective view of the entire clarification device to visualize the connections between its individual parts,

F i g. 2 the primary filter chamber of the clarifier of FIG. 1 in partially cut frontal perspective.
3 shows the secondary filter chamber of the clarifier of FIG. 1 including the devices for discharging the accumulated impurities, also in a partially sectioned frontal perspective.

Fig. 4 the mixing chamber and the facilities and

Mechanisms for adding filter aids to the clarifier of FIG. 1 again in part cut frontal perspective.

5 shows a partial section through the filter mechanism used in the primary filter chamber,
F i g. 6 is an end view of the FIG. 5 for a clearer illustration of the means for detaching the used filter cake and for drawing off the clarified liquid from the primary filter chamber.

F i g. Figure 7 is a section through the filter mechanism in the secondary filter chamber.

F i g. 8 is a front view of the FIG. 7 filter shown to better illustrate the facilities for removing the accumulated sludge and others Material from the filter mechanism,

F i g. 9 is a partial rear view of the outlet of the primary filter chamber and the connected thereto Lines and

Fig. 10 is a partial rear view of the outlet the secondary filter chamber and the lines connected to it.

The in F i g. 1 clarification device shown as a whole has a primary filter mechanism 100, a secondary filter mechanism or desludger 200 and precoat 300. As best F i g. 1 and 2 show, unclarified liquid is obtained from a main pump 10, which can be any commercially available Can be of construction, sucked in and through a pressure line It to an inlet 13 for the primary filter mechanism 100 pumped. A check valve 12 is built into the pressure line 11 which only allows the uncleared liquid to flow in one direction. Between the check valve 12 and the inlet of a filter pump 20 is a shut-off valve 14 in the pressure line 11 through which the Pressure line 11 can be shut off for maintenance purposes. The main pump 10 and the filter pump 20 work in series and pump the unclarified liquid together into a primary filter chamber

110 in the primary filter mechanism 100.

The primary filter mechanism 100 with the primary filter chamber 110 is at the top with a cover 111 closed, which is detachably attached to it and allows easy maintenance of the internal fittings. At the bottom, the primary filter chamber 110 is through a cone 114 liquid-tight closed, the solid dari »; is arranged and the unexplained supplied via the main pump 10 and the filter pump 20 Absorbs liquid. At the bottom of the cone 114 is a Outlet 115 attached, which is connected to an outlet line 117 in Connection is that enables a transfer of material to the secondary filler mechanism 200. Between the outlet 115 on the cone 114 and an inlet 209 into the secondary filter mechanism 200 is a shut-off valve 118 is inserted into the outlet line 117, which enables a shut-off for maintenance purposes.

The unclarified liquid introduced into the primary filter mechanism 100 is filtered by means of a primary filter 150 clarified in the primary filter chamber 110 and leaves the primary filter chamber 110 in clarified State through a filter outlet 50. whereupon they depending on the current operating phase of the clarifier is set in renewed circulation, discarded or sent to the Precoat device is passed, as explained in detail below. The primary filter 150 includes a hollow filter tube 162 that is used to facilitate its removal from the primary filter chamber 110 is designed in two parts and rotatable in a filter bracket 151 or on the filter chamber 110 attached the other end is seated in a sealed bearing housing 156. How best F i g. 5 shows is the filter tube 162 closed at both ends and has bores 153 through it. through the clarified Liquid can escape from the primary filter 150.

On the filter tube 162 are coaxial therewith and with mutual separation by spacer rings 164 disc-shaped filter elements 160 mounted so that the holes 153 in the filter tube 162 each with the Connect inside a filter disc. Each filter element 160 has one with a fine mesh Screen 168 covered support structure 167, which is formed from an accordion-like folded flat sheet material is. from the center of the respective filter element 160 extends radially outward and according to the Tapered outer edge. The sieves 168 each have such a mesh size. that when pumping through of the uncleared liquid through the respective filter element 160 are all suspended in the liquid Solid particles approximately 47 microns in diameter and larger are retained on screen 168. However, this mesh size for the sieves 168 is only one possible example and it depends in each case on the Particle size of the filter aids used and the impurities suspended in the liquid to be clarified away. The filter elements 160 each have an annular rim 169 on their outer edge. the is attached there with an overlap of the sieve 168 and the outer edge of the respective filter element 160 seals.

Wipers 180 are arranged between the individual filter elements 160; serve to clean the surface of the filter elements 160 as explained. The wipers 180 are seated each on the spacer rings 164 between two adjacent filter elements 160 and stand with their facing surfaces in contact. The filter elements 160 are relative to the wipers 180 rotated, the entire surface of the filter elements 160 is subject to this relative movement cleaning wiping effect.

Leder wiper 180 has a wiper arm 181 which is covered with brush bristles 182. from filter tube 162 extends radially outward and is guided around the respective spacer ring 164 to support it. At A stop 186 is attached to the wall of the primary filter chamber 110, to which the wiper arms 181

ίο come to the system, which means that the Wiper 180 with the filter tube 162 when rotating the filter elements 160 is prevented. The wipers 180 therefore remain in a stationary state, and their brush bristles 182 sweep the entire surface of the corresponding filter elements 160 when they are set in rotation via a drive 140.

Practical tests have shown that the speed for the rotation of the filter elements 160 relative to the Wipers 180 should be selected so that there is a relative speed between filter elements 160 and wiping 180 of no more than 2.5 m / min, and preferably between about 0.5 and 1 m / min, since then the material of the used filter cake breaks loose from the sieves 168 in large pieces which are in the surrounding liquid will quickly settle to the bottom.

When operating the clarifier shown

the main pump 10 and the filter pump 20 are energized and pump unclarified liquid from a corresponding source in the cone 114 in the primary Filter chamber 110. Due to the pumping action of both pumps, a primary filter chamber 110 becomes a Pressure creates that the unclarified liquid through the Filter elements 160 pushes through, with clarified liquid then exiting into the filter tube 162 and from this is passed on, while the impurities carried in the filter cake on the outside of the Filter elements 160 are held in place, the passage openings for the passage of the liquid laying more and more through the filter elements 160 and the one for forcing liquid through the filter elements 160 required pressure gradually. increases.

As soon as a certain pressure value is reached with this pressure increase, a pressure-sensitive speaks Switch 190 on and causes the operating mode of the clarifying device for the filtering process to be switched off to renew the used filter cake material sitting on the sieves 168. Through the lock Ben the switch 190, the drive 140 for the rotation of the primary filter 150 is set in motion, and the Filter elements 160 brush the stationary wipers 180 along, whereby the used up Filter cake is dislodged from the screens 168 and into the uncleared liquid in the primary filter chamber 110 goes into suspension.

The main pump 10 and the filter pump 20 are used to transport away the used filter material shut down while a desludging pump 30 and a feed pump 40 go into operation. the Desludging pump 30 is a vacuum pump and draws liquid through a secondary filter 250 from a secondary filter chamber 210 of the secondary filter mechanism 200. After going through Filter elements 260 of the secondary filter 250, the liquid is drawn into the precoat device via an outlet line 31 300 is fed with a check valve 32 inserted into the outlet line 31 for this purpose ensures that the liquid the outlet line 31 only in

230 225/78

can flow through in one direction.

When the contents of the primary filter chamber 110 over withdrawn the outlet 115 at the bottom of the cone 114 and has been introduced into the secondary filter mechanism 200, the suspended particulate matter becomes just like the used filter cake is collected on the Filierelemer.ien 260 of the secondary filler 250. The secondary filter 250 includes a hollow filter tube 262 that is used to facilitate its removal from the secondary The filter chamber 210 is designed in two parts and rotatable in one attached to the filter chamber 210 Filter console 251 or at the other end in a sealed bearing housing 256 is seated. The filter tube 262 is closed at both ends and has bores 263 through it.

On the filter tube 262 are coaxial therewith and with mutual separation by spacer rings 264 Disc-shaped, the filter elements 260 of the secondary filter 250 are mounted in such a way that the bores 263

• n »nt!
Jl.

Filter disc are connected. Each filter element 260 has one with a fine mesh screen 268 covered support structure 267. which is formed from an accordion-like folded flat sheet material. from the Center of the respective filter element 260 extends radially outward and towards the outer edge rejuvenates. The screens 268 each have such a mesh size. that when pumping through unclarified liquid means all solid particles in it that are approximately 47 microns in diameter and more to be held on to the seven 268. The filter elements 260 each have on their outer edge a ring rim 269. which is attached there with an overlap of the corresponding screen 268 and the Seals the outer edge of the respective filter element 260

Wipers 280 which are used to clean them are arranged between the individual filter elements 260 each sit on the spacer rings 264 between two adjacent filter elements 260 and with their facing surfaces are in contact. Are the filter elements 260 relative to the If the wipers 280 are rotated, the entire surface of the filter element is subject to this relative movement elements 260 of a cleaning wiping effect.

leather wiper 280 has a wiper arm 281 which is covered with brush bristles 282. from filter tube 262 extends radially outward and is guided around the respective spacer ring 264 to support it the wall of the secondary filter chamber 210 has a stop 286 for the wiper 280 attached to it Prevents rotation with the filter tube 262 during the rotation of the filter elements 260. the Wipers 280 therefore remain in a stationary state, and their brush bristles 282 sweep the entire Surface of the corresponding filter elements 260 when they are set in rotation by a drive 216 will.

When the desludging pump 30 is started, pressure builds up in the outlet line 31, the in turn, a positive pressure in a control line 36 can arise from the outlet line 31 to a Diaphragm valve 37 carries this in outlet line 117 between outlet 115 of the primary filter mechanism 100 and the inlet to the secondary filter mechanism 200 is The pressure in the control line 36 causes the diaphragm valve 37 to open and holds it. «■ open long as the desludging pump 30 is in operation Fm inlet 209 to the secondary filter chamber 210 is a float valve 235 that controls the supply of liquid to the secondary filter chamber 210 and serves to maintain a suitable level of liquid therein. As best Fig. 3 shows, the inlet 209 opens into the secondary filter mechanism 200 in a turbulence preventer 205, the pocket delimited by the wall of the secondary filter chamber 210 and plates 211 is designed and to reduce the turbulence in

ίο those entering the secondary filter chamber 210 Serves fluid to a minimum.

As already mentioned, the desludging pump 30 and the feed pump 40 both start up when the contents of the primary filter mechanism can be transferred to the secondary filter mechanism 200 target. The desludging pump 30 draws off the liquid that has passed through the filter elements 260 and brings it via the outlet line 31 into the precoat device 300. At the same time, the S ^ eise ^ 'jm ^ e 40 den! Nhsit a mixing chamber 310 m the precoat 300 and feeds it through an inlet 120 into the primary filter chamber HO. To maintain a fixed liquid level in the secondary filter chamber 210 and to avoid it overflow due to differences in pumping capacity between desludging pump 30 on the one hand and the feed pump 40 on the other hand is between the secondary filter chamber 210 and the Mixing chamber 310 an overflow line 70 is provided as the filter elements 260 of the secondary filter 250 Collecting sludge and filter aids added in the manner explained in detail below decreases the suction capacity the desludging pump continuously. during the inflow from the feed pump 40 approximately remains constant. It is therefore necessary during the Recirculation of the sludge and filter aids with it leading liquid to overflow to compensate for the changes in the delivery capacity of the desludging pump 30.

AO Start-up of the feed pump 40 is a control line 41 under pressure, the processing between the output of the feed pump 40 and the inlet 120 into the primary filter chamber 110 to a leading from the feed pump 40 to the primary filter chamber 110 Auslaßlei · is connected 42nd The control line 4t leads to membrane valves 44 and 45, which are located at the filter outlet 50 for the primary filter 150 or in a line 33 branching off therefrom. The pressure in the control line 41 closes the normally open diaphragm valve 44 in the filter outlet 50 and acts on the normally closed diaphragm valve 45 as opening pressure. Another control line 61 connecting the diaphragm valve 45 to the desludging pump 30 is dimensioned so that the closing force exerted therein on the diaphragm valve 45 during operation of the desludging pump 30 is sufficient to keep the diaphragm valve 45 closed against the force acting on it via the control line 41. The pressure in the control line 41 thus closes the diaphragm valve 44, and the pressure in the control line 61 also keeps the diaphragm valve 45 closed, and both diaphragm valves 44 and 45 maintain this closed position as long as the feed pump 40 and the desludging pump 30 are in operation In the exemplary embodiment shown, the actuation of the diaphragm valves 44 and 45 takes place by means of liquid pressure, but instead an equivalent valve actuation could also be carried out, for example by means of

tucked air or with electrical supply from Solenoid valves are provided.

Closing the diaphragm valve 44 prevents further transport of the unexplained at the outlet 50 of the Primary filter 150 escaping liquid from the "<clarifier. Maintaining the closed position for the diaphragm valve 45 prevents any fluid from being recirculated through the primary Filter chamber 110. The circulation of the liquid in this Way and with closed membrane valves 44 and m 45 therefore brings all sludge such as suspended or partially dissolved solid particles and used up Filter cakes in a self-contained system are cleaner without contamination Container from the primary filter mechanism 100 to the secondary filter mechanism 200.

The clarified when passing through the secondary filter 250 and passed on via the outlet line 31 Liquid flows into the mixing chamber 310 of the precoat coating 300, where it is mixed with a predeterminable Quantity of filter aids is added. The resulting turbidity in the Ma.hkammer 310 is through the inlet 120 is introduced into the primary filter chamber 110 and there with the sludge contained therein mixed. This mixture is then passed to the secondary filter mechanism 200. to go to the Sieves 268 of the secondary filter 250 to form a filter cake. The mixture of filter aids and Sludge forms a filter cake with a predeterminable porosity, which forms the partition wall of the secondary filter 250 protects.

After the liquid has circulated in the closed internal circulation system, the filter elements 160 of the Primary filter 150 cleaned and ready for further filtration. The one for this internal fluid circulation time required is usually four to five minutes, and the process of accumulating Sludge on the secondary filter 250 can be determined by the purity of the inlet 209 into the secondary filter mechanism 200 through an inserted into the outlet conduit 117 Sight glass 201 is observed through.

After the operational phase of sludge transfer is complete. become the desludging pump 30. the feed pump 40 and the drive 140 for rotating the filter elements 160 of the primary filter 150 turned off and thus made the control lines 36,41 and 61 depressurized, so that the diaphragm valves 44 and 45 return to their normal relaxed or depressurized positions.

After the completion of the sludge transfer phase described above, the filter pump 20 and the Feed pump 40 started up. Since the system is completed by actuating the diaphragm valve 44 has been, the liquid in the closed system is continuous through the mixing chamber 310 of the Precoat 300, the primary filter chamber 110 and the secondary filter 250 of the secondary Filter mechanism 200 rotated through, with all suspended and partially dissolved solid particles and filter aids have accumulated on the filter elements 260 and the liquid in the closed System has been resolved and is ready for further use

The filter pump 20 draws from a housing 60 connected to the filter outlet 50 for pure liquid clarified liquid and feeds it into the cone 144, with a liquid circulation through the Primary filter 150 of the primary filter mechanism 100 to the outside through the housing 60 for Clean liquid back through the filter pump 20 and into the primary filter chamber 110 which results in a self-contained system. The feed pump 40 draws liquid from the mixing chamber 310 and feeds it into the primary filtering chamber 110 via the inlet 120.

As soon as the feed pump 40 is running, the others succeeded Control line connected to the pressure side 41 riter Pressure and opens the diaphragm valve 45 and closes the diaphragm valve 44 and both diaphragm valves 44 and 45 remain in these positions as long as the feed pump 40 is in operation. In this position the diaphragm valves 44 and 45 result in a liquid circuit in which the clarified liquid from the filter outlet of the primary filter 150 through the diaphragm valve 45. a non-return valve 43 in the line 33 into the mixing chamber 310 the precoat device 300 flows into it. The check valve 32 prevents this in the outlet line 31 a backflow of discharged liquid and its entry into the secondary filter mechanism 200.

To form a deposit or a new filter cake on the sieves 168 of the primary filter 150 with the feed pump 40 running for the actuation of the diaphragm valves 44 and 45 for formation of the closed circuit, a feeder anti-vibration motor 80 is activated in each of three Filling funnels 340, 350 and 360 for filter aids a stirrer 320 and a feed screw 330 in Offset. The filling funnels 340, 350 and 360 are completely identical in their internal structure, therefore, only the hopper 340 is described in detail below to simplify the illustration described, wherein the specified reference numerals m the other two filling hoppers 350 and 360 Designate the corresponding components.

The mixing chamber 310 is designed as a liquid-tight housing and has an outlet 311 of the Mil is connected to the feed pump 40. The feeder drive motors 80 for the individual hopper 340, 350 and 360 are each appropriately attached thereto and offset one in each of them Longitudinal shaft 341 in rotation, on which the stirrer 320 and the Speiseschn.jke 330 des relevant funnel 340, 350 or 360 are attached. The bottom of the hopper 340, 350 and 360 is each formed in the shape of a cone 343 which is fixed within a funnel chamber 345 and all material contained therein can only exit through an outlet 344 at its base. D. Shaft 341 is attached to each of the hopper 340, 350 and 360 in a respective one at the bottom thereof Console and rotatably mounted in a decker 342 that closes it at the top, a portion of the lid each 342 is hinged to the rest of it and can be used to refill filter aids if necessary unfold.

When the feeder drive motors 80 are started up, a gear ratio and the pitch are determined accordingly the feed screw 330 a predeterminable amount of filter aids or filter material into the mixing chamber 310 introduced Due to the turbulence of the liquid in the mixing chamber 310, a Cloudy. which is pumped into the primary filter chamber 110 by the feed pump 40, where on passage through the filter elements 160 of the Frimärfüters 150 the filter aids or filter materials on the sieves

168 and cover them to form a new filter cake that allows the clarified liquid to recirculate through the mixing chamber. When the specified amount of filter aids or filter material is placed in the mixing chamber 310>. If the feeder ancillary motors 80 are stopped, the feed pump 40, on the other hand, continues to operate and continues to convey liquid from the mixing chamber 310 through the inlet 120 into the primary filter chamber 110. When the liquid mixed with the filter aids passes through the filter elements 160, the filter aids are retained on the sieves 168 of the filter elements 160, and the cleaned liquid flows back through the mixing chamber 310. This liquid circulation '■' is continued until a sight glass 47 inserted into the outlet line 42 becomes clear, which indicates that the filter elements 160 are completely covered and the mixing chamber 310 of the precoating device 300 is completely clean.

After completion of this precoat phase in the operation of the clarifier, the feed pump 40 r.illgeset / t, and the diaphragm valves 44 and 45 are returned to their original position. The filter pump 20 remains in operation, and the main pump 10 is newly in: '> Gauged to introduce unclarified liquid into the primary filter chamber 110 for clarification.

"When the clarifying device goes back into operation to clarify liquid, which is pumped by the main pump 10 through the F. inlet 13 into the primary filter chamber 110 J" and exits therefrom in the clarified state through the outlet 50, the float valve 235 in FIG secondary filter chamber 210 as well as a float valve 335 in the mixing chamber 310 an entry of liquid from the filter outlet 50. as is necessary for the maintenance of the given liquid level in these two chambers Liquid and the outlet pipe 117 which is inserted from the outlet 115 of the primary filter chamber 110 / around the inlet 209 of the secondary (illerkammer 210) opens into the outlet pipe 117 below the diaphragm valve Y! And allows a partial flow through the outlet 115 during operation «· · Of the main pump 10. to prevent clogging or obstruction of the first outlets / u prevent and maintain a continuous winding action

When the primary filter mechanism comes back into operation with renewed b / w refilled> <> Filter elements 160 and the main pump 10 / u clarifying liquid wedge promotes and via inlet 13 in the primary filter chamber 110 is pumped in, then im secondary filter mechanism 200 automatically removes the accumulated filter cake from the filter elements> '. 260, ibgelost and the material consumed b / w the Sh'.imm expelled for final disposal

When the primary filter mechanism 100 begins the filtering phase, the drive 216 is ^{set in motion for the rotation of the filter elements 260 of the secondary filter 250 s 1} - ¹ relative to the wipers 280, and in the course of this rotation the wipers 280 scrape off the filter cake the sieves 268 of the filter elements 260. Via a belt drive 213, the drive 216 also acts on a horizontal screw 220 accommodated in the secondary filter chamber 210 and sets it in rotation. At the same time, a further drive 226 is also set in motion, which causes a central vertical screw 230, a scraper 234 and a further vertical screw 240 to rotate.

How best F i g. 3 / eigt, the bottom is the secondary filter chamber 210 designed as a cone 214 and sealed so that liquid only through one Outlet 215 can exit from the secondary filter chamber 210 at its base. The central snail 230 is located within outlet 215 in cone 214 and in secondary filtration chamber 210 rotatably mounted, a portion of a shaft 231 through a liquid-tight seal at the lower end 218 of the worm 230 exits and carries a gear that serves as a link to the drive 226. That the other end of the shaft 231 carries a horizontal web of the scraper 234. the downwardly bent web of the scraper Ends run approximately parallel to the cone 214 and run past it on the inside.

The scraper 234 is used to prevent accumulation of sludge in the cone 214. The one from the Sludge detached from seven 268 of the filter elements 260 sometimes tends to collect in the cone 214, and the sharp edges 236 of the downwardly facing ends of the scraper 234 then prevent one Accumulation of mud on the walls of the cone 214.

The central screw 230 is designed to be left-handed and guides the sludge down to a central one Opening 217 at the C'unde of the cone 214 closed. through which he reaches the horizontal screw 220 via the outlet 215. The horizontal scroll 220 is inside a tube 221 which is closed at one end and at the other end with the inlet A section of a shaft 222 of the horizontal screw is connected for the further vertical screw 240 Screw 220 is guided out through the closed end of tube 221 and at the point of passage sealed liquid-tight. A belt drive is attached to the protruding section of the shaft 222 213 associated disk wedged, so the connection to the drive 216 produces

When the sludge passes through the central auger 230 and into the horizontal auger 220 is transported, it gives it to the further vertical Screw 240 further This screw 240 is rotatably mounted in an end cap 241, which forms a liquid-tight seal for a SaUc 242 in which the Auger 240 is housed in a section of the fin The shaft 243 of the worm 240 extends through the end cap 241 to the outside and carries cm there Gear 245 that connects to / around drive 226. The column 242 is secured by means of suitable brackets externally attached to the wall of the secondary filter chamber 210. The upper end of the column 242 is through a Cap 246 completed which is a bearing for the Receiving the uppermost portion of the vertical shaft 243 of the auger 240 also includes points the cap 246 has a ventilation opening ai (through you in the Spiral 240 b / w in column 242 ascending Steam ie according to its nature / u further Treatment of / ϋ! Π free exit into the atmosphere can escape.

Will the vertical auger 240 through the horizontal If the screw 220 is fed with sludge, it transports it upwards, passing it through a heater heated and more or less dried. This heating can be as in the example shown can be implemented by means of steam jackets, but other suitable precautions can also be taken.

for example by providing electrical resistance heating.

As FIG. 3 shows, there are two sitting on the column 242 Steam jackets 270 and 290 connecting supply and return lines containing valves to a steam source are connected that either one or the other or both can be heated, the Selection of the heating depending on the properties of the column 242 upwards transported sludge and the desired type of its extraction - in half or completely dry State - is hit. It has been shown that because of the mechanical action of the screws 230, 220 and 240 on the sludge, heating of the vertical screw 240 is required even then when the mud is in a very hard state. The action of the snails on the mud results without heating the column 242 to such a mechanical working through of the material that the mud especially at very low speed due to the vertical snow ^ ** 240 nich ' can be transported upwards. Therefore, by heating the screw 240, some of the in the sludge in the Excess liquid evaporates to keep the sludge in a state in which it is lets lift. The vertical screw 240 has a section 244. which is free from spiral windings. In this way, sludge is formed in the sludge conveyed upwards by the screw 240 Gate 244 is a solid block that prevents excess fluid from rising, causing the Seeks to equalize the liquid level in the secondary filter chamber 210.

As shown in Figure 3, the lower steam jacket extends 290 starting from below the opening 217 in the cone 214 upwards, while the upper steam jacket 270 extends upward beyond the upper end of the secondary filter chamber 210. The ones from Heat given off by the lower steam jacket 290 brings the solid / liquid mass below the sludge block in section 244 for boiling, the liquid evaporating within this section of column 242 and optionally dewater the contents of the secondary filter chamber 210 as a result of this boiling process will. The upper steam jacket 270 is used to control the moisture content remaining in the sludge, after the formation of the mud block in section 244 and the lifting of the mud by the Auger 240 through the portion of column 242 adjacent to steam jacket 290. By Controlling the heat given off by the steam jacket 270 allows the sludge to operate in various ways Eject moisture stages.

- For best results when operating vertical auger 240, it should be operated intermittently so that the warmth of the sludge during its gradual rise over a longer period of time can dry. When the mud is the top of the

ίο vertical auger has reached 240, he will go through a deflector 248 attached to the top of the screw 240 and revolving with it out of the column 242 pushed to the outside and enters a sludge downpipe 275, through which it enters a suitable

ii Litter bin falls.

At first start-up, or whenever there is no sludge in column 242, it is preferable to add some filter aid to column 242 to create a first block in section 244 of auger 240. In this way, a block of material is available for easier sludge application. In Fig. 3 only shows a section 244 free of screw windings, but it can sometimes be from Voiteil, depending on the

r, the special application for the clarifier zvvei, three or more such winding-free sections 244 to be provided.

The mud block forming in the winding-free section 244 of the screw 240 presses the

so liquid out of the solid mass, if further Sludge is conveyed upwards and thereby hits the underside of the sludge block, so that its the top part is raised, squeezing out the liquid. When training the snail

r. 240 with several non-winding ones arranged one above the other In sections 244, the lower mud blocks act as a series of filters that Remove suspended solid particles from the liquid that has been forced through. The passage of the liquid

through the lower mud blocks in the unwinding ones Sections 244 of the screw 240 depends on their position and thus the position exerted on them Print head due to the liquid level in the secondary filter chamber 210. When this drops,

ii the lower blocks with filter effect are considered the upper ones Act block and move liquid out of the mud by touching the mud underneath of the block exert a pressure.

To do this, draw 5 sheets of paper

230 225/78

Claims (21)

Patent claims: 1. Process for clarifying impurities containing liquid, in which unclarified liquid passed through a primary filter that retains the impurities and behind it clarified liquid is discharged, impurities accumulated on the primary filter with interruption passing liquid through the primary filter thereof into the unclarified liquid detached into it and fed with this to a secondary filter that retains the impurities clarified liquid is returned to the primary filter after passing through the secondary filter and impurities accumulated on the secondary filter The secondary filter is detached from it by interrupting the passage of liquid through the secondary filter and discharged, characterized in that that the passage of liquid through the primary filter in each case after accumulation one v. -given amount of impurities on the Prsmarfilter is interrupted, the Primary filter from the secondary filter supplied liquid a certain amount of filter material for the renewal of the filter layer on the primary filter is added and that detached from the secondary filter Impurities fed to a vertical screw, in this under transport from below at the top until at least part of the liquid contained therein has evaporated, and in particular at least partially dehumidified blocks are pressed together by gravity. 2. The method according to claim 1, characterized in that that the passage of liquid through the primary filter is interrupted when the pressure drop across the ί primary filter as a result of the Accumulation of impurities on it has reached a predeterminable value. 3. The method according to claim 1 or 2, characterized in that the detachment of the contaminants -to from the primary filter and / or the secondary filter by brushing. 4. The method according to any one of claims 1 to 3, characterized in that the secondary detached impurities are caused to settle by gravity. 5. The method according to any one of claims I to 4, characterized in that the secondary filter to renew its filter layer after the impurities have been removed with filter material displaced clarified liquid is supplied. 6. The method according to any one of claims 1 to 5, characterized in that the secondary filter detached impurities are heated until the liquid contained then boils. 7 The method according to any one of claims 1 to 5, characterized in that from the secondary filter detached impurities are formed several separate blocks, of which the each lower act as a filter for solid particles suspended in the entrained liquid. 8. The method according to claim 7, characterized in that during the upward movement of the Impurities and the formation of blocks from it a rise of liquid to above that Height of the blocks is prevented. 9. The method according to claim 7 or 8, characterized in that during the upward movement the blocks formed from the impurities removed by the secondary filter the lowest used as a filter to hold back suspended solid particles and the uppermost is compressed to remove liquid wedge from it. 10. The method according to any one of claims 1 to 9, characterized in that the secondary filter detached impurities in an intermittent movement upwards and ir be moved through a heating zone. 11. Device for clearing impurities containing liquid in carrying out the method according to any one of claims 1 to 10 with a first filter chamber containing a primary filter and a second filter chamber containing a secondary filter, which is connected via liquid lines connected to each other and with devices for detaching from the respective filters accumulated impurities are provided for their removal from the relevant filter chamber are characterized in that the first filter chamber (110) is one in response to the accumulation a certain amount of impurities on the primary filter (150) the further introduction of unclarified liquid in the first filter chamber interrupting and the detachment of the impurities from the primary filter into the unclarified liquid in the first filter chamber Has switch (190) and the second filter chamber (210) via a filtrate outlet (31) with a on the outlet side with the high pressure side at least connected to the first filter chamber and at least one inlet (340, 350, 360) for the introduction a predeterminable amount of filter material having mixing chamber (310) and a solids outlet (217) with a conveyor device with at least one on at least one section their length behei / ble screw (240) with vertically upward conveying direction for the Application from the front secondary filter (250) detached Filter cake from the second filter chamber is connected. 12. Apparatus according to claim 11, characterized in that the switch for the interruption the supply of unclarified liquid and the initiation of the detachment of the impurities in the first filter chamber (110) on the pressure drop more responsive pressure-sensitive on the primary filter (150) Switch (190) is 13. Device according to claim 11 or 12. characterized in that the primary filter (15G) and the secondary filter (250) each has a plurality of, in particular, disk-shaped hollow filter elements (160 b / w 260) with from coaxially arranged Seven (168 or 268) existing partitions, which are used as facilities / in order to detach them wipers (180 or 280) which can be moved from the filter cake relative to the filter surface with on the filter surfaces brush bristles brushing along (192 b / w 282) supporting wiper arms (181 or 281) / ugeord are net. 14. Device according to one of claims 11 to 13, characterized in that the mixing chamber (310) a part of a precoating device (300) for precoating new filter layers on the Forms the primary and / or secondary filter (150 or 250) and with at least one one that can be specified Amount of container containing filter material (345) is connected, the one circulating therein to avoid the filter material caking together Stirrer (320) and each a certain amount; of filter material feeding into the mixing chamber Contains auger (330). 15 Device according to one of claims 11 to 14, characterized in that the conveying device for the discharge of the filter cake from the second filter chamber (210) in front of the screw (240) with an upward conveying direction vertical arranged coaxially and centrally to the solids outlet (217) of the second filter chamber Screw (230) with a downwardly directed conveying direction i-nd a passing c horizontal screw (220) and then to the screw with upward conveying direction a jointly rotating deflector (248) for the deflection of the one from the preceding Has screw exiting filter cake to a receptacle (90). 16. Device according to one of claims 11 to 15, characterized in that at least one section of the conveyor device (220, 230, 240) a heating device for discharging the filter cake from the second filter chamber (210) (270, 290) is arranged, the heating power of which to evaporate at least part of the in the promoted The liquid contained in the filter cake is sufficient. 17. The apparatus of claim 16, daduich characterized in that the heating device for the conveying device (220, 230, 240) consists of surrounding it and steam jackets (270,290) connectable to a steam source. 18. Apparatus according to claim 16 or 17, characterized in that the heating of the Conveyor device (220, 230, 240) can be independently regulated on its individual sections. 19. Device according to one of claims Ib to 18. characterized in that the heatable Zone of the conveyor (220, 230, 240) of at least one below the solids outlet (217) of the second filter chamber (210) located point of the vertical screw (240) with after upward conveying direction up to one above the cover of the second filter chamber located point of this tendon is enough. 20 Device according to one of claims 11 to 19. characterized in that the conveyor (220, 230, 240) for the discharge of the filter cake out of the second filter chamber (210) to an intermittent filter cake feed, in particular through the heatable zone is set up. 21. Device according to one of claims 11 to 20, characterized in that the vertical screw (240) with an upwardly directed Förderchning on at least a medium one Part (244) of its shaft (243) is free of screw windings. 22 Device according to one of claims 11 to 21, characterized by an automatic one controlled by pressures prevailing at certain points Sequence of their individual operating phases in such a way that triggered by the Accumulation of a predeterminable amount of impurities on the primary filter (150) the introduction of unclarified liquid into the first filter chamber (110) and the drainage of clarified liquid via a corresponding filter outlet (50) is interrupted subsequently remove the accumulated impurities from the surface of the primary filter detached, together with unclarified liquid from the first filter chamber into the second filter chamber (210) and there on the secondary filter (250) with the assistance of previously from the mixing chamber (310) deposited filter material to be deposited and introducing from behind the Secondary filter clarifies escaping liquid with filter material added to the mixing chamber Primary filter a new filter layer is washed ashore, which then concludes the first Filter chamber against the second filter chamber and the mixing chamber of the filtering process in the first Filter chamber begins again, while in the second filter chamber the discharge of the accumulated Impurities takes place.