GB2073040A

GB2073040A - Filter press

Info

Publication number: GB2073040A
Application number: GB8110722A
Authority: GB
Original assignee: Eberhard Hoesch and Soehne GmbH and Co
Current assignee: Eberhard Hoesch and Soehne GmbH and Co
Priority date: 1980-04-05
Filing date: 1981-04-06
Publication date: 1981-10-14
Also published as: FR2479702B1; ES8201031A1; ES500081A0; IT1142662B; FR2479702A1; DE3013313A1; IT8147964A0; GB2073040B

Abstract

A filter press, comprising a plurality of vertical filter plates horizontally displaceable on at least one guide support of a press frame by reciprocating transport means 7, is provided with a plate-washing means 10 with vertically moving spray nozzles. Washing means 10 is provided with a brake actuated by the transport means, so that after the transport means 7 has moved a plate to be washed into the washing position by a forward movement (leftwards) the subsequent return movement of the transport means 7 (rightwards) releases the brake, moves the washing means one step into precise alignment with the said plate and resets the brake until the washing step is completed. The plate movement and washing are thus completely automatic. <IMAGE>

Description

SPECIFICATION Plate filter press with built-in washing apparatus for the filter plates The invention relates to a plate filter press wherein vertically aligned filter plates are mounted to be horizontally displaceable on at least one guide support of the press frame and each filter plate is provided with at least one fixed projection, and wherein a transporting apparatus is provided having a supporting element which can be moved to and fro by means of a drive in the opening gap between the filter plates and which is provided with an entrainment means abuttable against the projection of the particular filter plate to be transported, and wherein a washing apparatus mobile in the longitudinal direction of the press provided for the filter plates, said washing apparatus having at least one nozzle pipe adapted to move transversely to the longitudinal axis of the press in the opening gap obtaining at the time in question in the set of filter plates.

With plate filter presses of the kind specified, for several fields of use the problem exists that in time the filter cloths situated on the filter plates become clogged so that filtering capacity falls off considerably. To clean, therefore, the filter cloths have to be sprayed down with water at high pressure. Nozzle pipes with a plurality of spraying nozzles are used for this purpose, the length of the nozzle pipes corresponding either to the filter plate width or the filter plate height depending on the guiding of the washing apparatus.To clean, the filter plates are first pushed together after emptying, and then, as for the emptying operation, individually staggered and the nozzle pipes moved slowly downwards from the top, for example with the nozzle pipes directed horizontally, the cleaning water from the nozzles impinging with high pressure on the filter cloth surfaces to be cleaned.

The cleaning effect in such a case is dependent not only on the pressure of the spraying water and the constructional form of the nozzles, but also on the spraying nozzles maintaining as constant a spacing as possible from the filter plate surface to be cleaned. In order to do this, either the filter plates are moved to a reduced opening gap size, so that it is possible with a nozzle pipe which is provided with nozzles at both sides and is moved in the middle of the opening gap, to clean the particular filter plate surfaces which adjoin the opening gap.

Or, in another cleaning system, the filter plate to be cleaned is moved approximately into the middle of the opening gap, so that two nozzle pipes with nozzles directed inwardly supply sprayed water to the filter plate to be cleaned at both sides at the same time.

But for both cleaning systems the problem basically exists that the filter plate to be cleaned and the washing apparatus have to be adjusted-in precisely to one another. More particularly the precise controlling of the washing apparatus into the opening gap presents problems, since the opening gap shifts in relation to the press frame because of the taking of press filter plates to be cleaned from the stack of set of plates at one side and the growth of the stack of cleaned filter plates at the other side.

Whereas plate filter presses both with filter plates arranged in suspended manner and also with filter plates supported on longitudinal bars by means of lateral noses or projections operate fully automatically as regards the successive operations of closing, filtering, opening for emptying, by means of a suitable control apparatus with the aid of limit switches and sensors, thitherto it has not been possible to automate the positioning of the washing apparatus in relation to the opening gap which shifts after each washing operation relatively to the press frame. Since various reference planes are important for the carrying out of the individual operations, and these are subject to varying, sometimes relatively large spacing changes, fully automatic integration of the washing apparatus cannot be covered with the usual control apparatus.The washing apparatus hitherto has been operated only as a so-called semi-automatic apparatus, wherein the moving and positioning of the washing carriage in relation to the shifting opening gap was effected always by hand, using key switches. Then only when the washing apparatus is positioned precisely manually could the individual washing operation movement components proceed automatically by means of a suitable control system. Accordingly the washing apparatus also has to be simplified relatively to the hitherto known washing apparatus, so that there is the optimum possibility of integrating the washing apparatus in accordance with the object to be achieved into the timed working cycle of a plate filter press as regards operating speed, operating reliability and cleaning efficiency.

The object is achieved in a preferred embodiment according to the invention in that a locking brake is arranged at the carriage of the washing apparatus, and that the transporting apparatus is connected to an actuating means which, at the return travel of the transporting apparatus, brings about the release of the locking brake and the travel of the washing apparatus in the direction towards the set of filter plates to be cleaned. This has the advantage that the transporting of the filter plates and of the washing apparatus requires only one drive means, namely the plate shifting or transporting apparatus, which moves the washing apparatus along only when, to take up a filter plate with its entrainment means, it moves in the direction towards the set of filter plates to be cleaned.The locking brake at the washing apparatus ensures that the washing apparatus always remains fixed in the position reached in relation to the set of filter plates to be cleaned on the press frame, until the particular cleaning operation concerned is concluded and the cleaned filter plate is moved to join the set of cleaned filter plates. Since as a result the opening gap between the two groups of filter plates has shifted relatively to the press frame by the thickness of one filter plate in the direction towards the group of filter plates to be cleaned, the washing apparatus is moved on by one filter plate thickness in the same direction by the return travel shortly before the conclustion of the return travel. The locking brake is thereat released by means of the actuating means.As soon as the entrainment means at the transporting apparatus has engaged a further filter plate, stops and reverses the direction of movement, the locking brake closes automatically, so that the position of the washing apparatus on the press frame and in relation to the opening gap is fixed. Then, by means of a suitably programmed control system, the transporting apparatus stops its transporting travel in the course of shifting the plate after it has moved over a predetermined travel distance, for example to the middle of the opening gap, so that the filter plate to be cleaned in then positioned precisely in relation to the nozzle pipe.It is particularly advantageous if the entrainment means is so arranged that during the transporting operation the filter plate is held positively by the entrainment elements i.e. when the transporting apparatus stops the filter plate cannot move onwards in uncontrolled manner in the direction of movement under the influence of inertia forces.

Thus it is possible on the one hand to control precisely into the washing position and on the other hand to move the washing apparatus before each washing operation solely with the help of the plate transporting apparatus.

In a preferred feature, in a plate filter press with a transporting apparatus which as supporting element has an endless-course roller chain or flat link chain connected to a drive, an entrainment means for the particular filter plate to be transported being secured on the said chain, it is proposed according to the invention that an abutment is secured on the chain with spacing from the entrainment means, as actuating means for the relase of the locking brake and for the moving of the washing apparatus, and that there is provided at the locking brake a mobile counterabutment which becomes operatively connected with the abutment and acts with a releasing effect on the locking brake, and at the same time serves as entrainment element for the washing apparatus.In this way, with the use of simple mechanical means, movement processes are coupled together in the transporting of plates and the travel of the washing apparatus, so that the necessary reliability in the complete cycle is ensured.

According to a preferred feature of the invention, more particularly in a plate filter press construction of the type specified hereinbefore it is proposed according to the invention that at the return travel of the transporting apparatus the abutment is secured in a "leading" situation on the supporting element of the transporting apparatus, here the chain, relatively to the entrainment means. This ensures that at the return travel, with release of the locking brake, the washing apparatus is first of all moved and that on engagement of the entrainment means on the filter plate to be transported for washing, which results in stopping of the transporting apparatus, the washing apparatus is already positioned for the next washing operation and immediately after reversal of the direction of movement of the transporting apparatus is held by the locking brake.The advantage of this arrangement is more particularly that a simple abutment is adequate for entrainment of the washing apparatus, and thus it is possible do do without complicated gripping element constructions.

According to a further advantageous preferred feature of the invention it is proposed that a pin associated with the abutment of the transporting apparatus is mounted, to be displaceable transversely to the plane of movement of the counter-abutment, on the counter-abutment of the locking brake. By withdrawing this pin the possibility of engagement between the abutment of the transporting apparatus and the counterabutment of the locking brake can be discontinued, so that the transporting apparatus can be moved without influencing the washing apparatus, or the washing apparatus can be moved by hand during the filtering and emptying operations into a position of rest at the end of the press frame.

According to a preferred feature of the invention it is also proposed that the locking brake is pressed by a spring on to the braking surface.

Although in principle electro-mechanically operating or hydraulically-mechanically operating locking brakes may also be used, the arrangement of a spring again affords the advantage of operating reliability and functional efficiency over a long period of time. It is particularly advantageous if the locking brake is so adjusted that the brake shoe travel required for the release of the brake relatively to the braking surface is kept as small as possible, since then the precision of the distance travelled by the washing apparatus at each movement operation can be further improved, since in this case only small actuating travels are necessary for the counter-abutment.

In a preferred feature of the invention it is also proposed that the locking brake acts on a running rail for the washing apparatus, said rail being secured on the press frame. Whereas in principle it is possible to make the brake act on one of the wheels of the carriage of the washing apparatus, if this arrangement is used the fixing of the washing apparatus on the press frame can be further improved since sliding phenomena between wheel and rail when braking are obviated. It is an expedient arrangement to make the brake application force act from below against the running rail, so that the running rail is clamped between the wheels and the brake in the arrested position.

In a preferred feature of the invention it is also proposed that a stop switch operating preferably without physical contact is arranged between the counter-abutment of the locking brake and the nozzle pipe holder on the carriage of the washing apparatus, said switch being adapted to be actuated by the abutment only at the transporting travel of the transporting apparatus and being so arranged that it switches off the drive of the transporting apparatus when the particular plate in engagement with the entrainment means is in the washing position. In this way the advantage can be enjoyed that because of the fixedly preset spacing between the entrainment means for the filter plate to be transported and the abutment displacing the washing apparatus any inaccuracies in the travel of the washing apparatus are eliminated.In the position of reversal of movement of the transporting apparatus the location of the abutment coincides with the position of the relevant point of the washing apparatus relatively to the press frame. Thus by means of this abutment it is also possible to determine exactly the travel which is required to move the filter plate to be cleaned into the washing position, since the arrangement of the switch on the washing apparatus, on the one hand and the initiation of the stop signal by the abutment of the transporting apparatus on the other hand make it possible to halt the filter plate being transported in a precisely defined situation in relation to the washing apparatus. As a result it is possible to fix the spacings between the nozzle mouths and the filter surface to be cleaned, and thus to use the mechanical action of the liquid jets to the optimum extent.

The possibility of adjusting the correct spacings between the nozzle mouths and the filter surface to be cleaned excludes the risk of collision between the nozzle pipe and the filter plate when the stop switch operates properly, since in fact the travel distance for the filter plate to be cleaned is defined by the washing apparatus itself.

According to another advantageous feature of the invention it is proposed to arrange on the carriage in the transporting direction after the stop switch a control switch preferably operating without physical contact, which is actuatable by the abutment in the transporting travel and which is operatively connected with a locking circuit at least for the nozzle pipe drive. This control switch is actuated when after the conclusion of the washing operation the cleaned filter plate is carried onwards. The control switch is so arranged that it is actuated only when the cleaned filter plate has moved completely out of the region of movement of the nozzle pipe or pipes.

In a further feature of the apparatus according to the invention it is proposed that there is arranged on the carriage a switch preferably operating without physical contact which is adapted to be actuated by that part of the entrainment means which acts on the filter plate being transported on engagement on the projection provided on the filter plate, and which is operatively connected with a locking circuit at least for the nozzle pipe drive. Because of the arrangement of which switch it is possible to enjoy the advantage that there is to be arranged on the entrainment means a movable nose or catch which at the return travel first of all is to run under the projection of the filter plate to be transported and in so doing is to carry out an appropriate to and fro movement.Only when this nose has engaged the projection of the filter plate to be transported, in other words has reached its initial position again, does the switch issue an appropriate signal and the locking of the nozzle pipe drive is accordingly released. As a result, the proper latching of the filter plate which is to be transported and cleaned is monitored and it is ensured that the drive for the moving of the nozzle pipe is capable of being switched on only when after receipt of a suitable control signal by the aforesaid stop switch a filter plate is also actually present in the washing position.

More particularly for a plate filter press whose press frame has two lateral guide bearers or bars on which the filter plates are guided by means of laterally protruding projections and are displaceable by means of laterally arranged transporting apparatus, and wherein the washing apparatus is adapted to travel in the longitudinal direction of the press on rails arranged laterally on the guide bars, to improve the integration of the washing apparatus in the sequence of movements of the plate filter press, according to a further feature of the invention is it proposed that the washing apparatus has a vertical guide member whose lower end is connected to the carriage running on one of the lateral rails, that a travelling slide connected to a drive is guided on the vertical guide member for upward and downward movement, and that the travelling slide is connected to a downwardly angled holding arm on the free end of which at least one horizontally directed nozzle pipe is secured. Such a washing apparatus is not only notable for having a relatively advantageous overall height, but also has the advantage that because of the downwardly angled holding arm which is secured directly on the travelling slide substantially rigid guiding of the nozzle pipe is ensured, free of any fluctuating deformations and thus varying spacings between the filter plate surface to be cleaned and the nozzle pipe even under the influence of high jet pressure in the case of liquid jets issuing unilaterally from the nozzle pipe, during the upward and downward movement A further advantage of this arrangement is that the nozzle pipe can be connected rigidly to be holding arm, so that firstly construction can be simplified and secondly a suitable control for the drive motor of the travelling slide and of a valve in the liquid supply duct to the nozzle pipes has simply to be provided for the control system of the plate filter press.

In the case of large plate formats, it is proposed according to a feature of the invention that the vertical guide member is supported by means of a supporting arm provided with a roller on a rail which is secured on the other guide bar.

In an advantageous preferred feature of the invention it is also proposed that at least above the nozzle pipe there are some arranged spray shield plates and/or brushes directed towards the filter plate surface to be cleaned. Such spray shield plate and/or brushes can be brought close up to the filter plate surface because of the precise positioning of the filter plate to be cleaned in relation to the washing apparatus, so that in this way a considerable improvement in spray shielding is obtained.

In an advantageous preferred feature of the invention it is also proposed that supporting parts directed towards the filter plate being cleaned are arranged in cases where two nozzle pipes with nozzle openings directed towards one another are provided on the holding arm respectively above and below the nozzle pipes, the spacing between each two mutually opposite supporting parts being slightly greater than the thickness of the filter plate. This has the advantage that, in the washing operation, the filter plates are supported directly in the region of the nozzle pipes and there cannot swing or tilt over even when varying jet pressures occur. The arrangement of two supporting parts situated above one another in each case, at each side, also ensures that the filter plate is held securely when the nozzle pipe passes over the projection region.More particularly in the case of plate filter presses whose frame has at least one guide support on which the filter plates are guided in suspended manner and wherein the transporting apparatus is mounted on the guide support and wherein the carriage of the washing apparatus is guided on the guide support, it is proposed according to a preferred feature of the invention that the carriage is connected to an endless traction means which is arranged above the chain of the transporting apparatus and whose lower run extends parallel to the upper run of the chain of the transporting apparatus, and which is provided in the region of the carriage with an abutment acting on the counter-abutment of the locking brake and at its lower run in the region of the upper run of the chain of the transporting apparatus with an entrainment element, and that a further entrainment element associated with the entrainment element on the traction means is secured on the upper run of the chain. This arrangement ensures, even in the case of the press construction mentioned hereinbefore, that in spite of the small space available in the region of the entrainment means it it is possible to effect the mechanical action on the washing apparatus carriage proposed according to the present invention, so that here also the advantageous precise positioning of the washing apparatus by a coupling arrangement with the filter plate transporting apparatus is guaranteed.

The invention will be explained in detail with the help of diagrammatic drawings showing constructional examples. in the drawings: Fig. 1 shows in side view a plate filter press the filter plates of which are supported by means of lateral projections on two lateral guide bars, Fig. 2 shows on a larger scale, in a section taken on the line Il-Il of Fig. 1, an end view of the washing apparatus, Fig. 3 shows a view of the washing apparatus at the carriage side, Fig. 4 shows on a larger scale details of the carriage of the washing apparatus, Fig. 5 shows a section through the carriage taken on the line V-V in Fig. 4, Fig. 6 shows a section through the carriage taken on the line VI-VI in Fig. 4, Fig. 7 shows a section taken on the line VIl-VIl of Fig. 4, Fig. 8 shows a view in the direction A of Fig. 2 with one arrangement of the nozzle pipes, Fig. 9 shows a view in the direction A of Fig. 2 with another nozzle pipe arrangement, Fig. 10 shows a view in the direction A of Fig. 2 with a further nozzle pipe arrangement, Fig. 11 shows a preferred constructional form with an entrainment means, Fig. 12 shows in a side view a plate filter press with filter plates arranged in suspended manner on an upper guide support.

The plate filter press shown in Fig. 1 comprises a press frame which is provided at both sides with guide supports 1, on which filter plates 3 bears by means of fixed lateral noses or projections 2. The group of filter plates formed of the pushedtogether filter plates 3 abuts at one end of the frame on an end plate 4 connected to the frame.

At the other end of the filter plate group a head plate 5 is mounted displaceably on the two guide supports 1, and is connected to a hydraulic cylinder 6 operating in the direction of the longitudinal axis. The group of filter plates can be pressed together with the use of the head plate 5 and the hydraulic cylinder 6, so that the joints between the individual filter plates are sealingtight during the filtration process. After the filtration process is concluded the filter press is opened by withdrawing the head plate 5, so that for emptying purposes the individual filter plates are transported successively with the use of a transporting apparatus 7 in the direction towards the withdrawn head plate.Then if after the emptying the filter plates are to be cleaned by a washing operation, first of all the group of plates abutting on the head plate after emptying is displaced in the direction towards the end plate 4 by means of the hydraulic cylinder 6 and then the head plate 5 is withdrawn again. Then, successively, using the transporting apparatus i, the filter plates 3 are again moved individually in the direction towards the withdrawn head plate 5.

To carry out the washing operation, a running rail 8 is secured to the guide bars 1 at the two sides of the press, and on said rail a washing apparatus 10 for the filter plates is mounted to be also displaceable in the longitudinal direction of the press by means of a carriage 9. By means of the transporting apparatus 7 the plates are then taken singly from the group of plates abutting on the end plate 4, transported to the washing apparatus, and cleaned there with the use of water under pressure and then moved from the washing apparatus to the head plate, so that the opening gap 11 remaining at the time concerned between the growing group of filter plates at the head plate 5 and the dwindling group of filter plates at the end plate 4 shifts in the direction of the end plate 4.Accordingly the washing apparatus 10 must also be displaced by the amount of one filter plate thickness in the direction towards the end plate 4 also before the cleaning of each filter plate. The construction of the washing apparatus and the coupling between filter plate conveyance and washing apparatus displacement will be explained in more detail hereinafter.

The washing apparatus 10 is shown in a section view in Fig. 2, seen from the end. The washing apparatus comprises substantially a vertical guide member 12 which at its lower end is supported by wheels 1 3 of the carriage 9 on the rail 8. Above the filter plates 3 there is secured on the vertical guide member a cross-member 14 which at its free end is supported by a running roller 15 on a rail 8' which is also connected to the press guide bar 1 situated at the other side.

Guided to be vertically slidable on the vertical guide member 12 is a travelling side member 16 which can be moved upwards and downwards in the vertical sense with respect to the vertical guide member by means of a drive motor 17 and suitable drive means, for example a roller chain of flat link chain guided over guide rollers 23, 24.

Secured on the travelling slide 16 is a downwardly angled holding arm 18 on the lower free end of which a horizontally aligned nozzle pipe 19 is secured which is provided with a plurality of nozzles 20 likewise directed horizontally, towards the filter plate 3. Water under pressure is supplied to the nozzle pipe 19 by way of a rigid of flexible conduit 21 secured to the holding arm 18, so that the filter plate surface can be sprayed down with a high pressure jet as the slide is moved downwards, to wash the said surface. The lowest position of the nozzle pipe is shown in broken lines in the drawings.

The sectional view also shows that the transporting apparatus 7 is guided laterally adjacent the two guide bars 1, and in the illustrated constructional example, as will be explained in detail hereinafter, said transporting apparatus is formed substantially of an endless roller chain orflat link chain at which an entrainment means is secured and which is connected with a drive motor 22 (Fig. 1) so that the entrainment means can be moved to and fro in the opening gap.

Fig. 3 shows a side view of the washing apparatus according to Fig. 2. As the side view shows, in this constructional form the vertical guide member 12 comprises vertical supports between which the travelling slide 16 is guided.

The connection between which the travelling slide 16 is guided. The connection between the travelling slide 16 and the drive motor 17 is established for example by a roller chain or flat link chain guided over guide rollers 23, 24 situated at the two ends of the member 12. The carriage 9 comprises substantially a supporting plate 25 on the ends of which the running wheels 1 3 of the carriage are held. That end of the supporting plate 25 which is directed towards the stationary end plate 4 is connected to a locking brake 26 which will be described in more detail as regards its construction with reference to Figs. 4, 5 and 6.

A counter-abutment 27 in the form of a rocking lever is mounted on the supporting plate 25, and is connected via a connecting rod 28 with a mechanism for the release of the locking brake 26.

Associated with the counter-abutment 27 on the supporting plate 25 is an adjustable abutment screw 29 whereby the rocking travel of the counter-abutment 27 from the illustrated position of rest in the direction cowards the abutment screw 29 can be adjusted.

As the detail view on a larger scale in Fig. 7 shows, the counter-abutment 27 is provided at its free end with a pin 31 which is displaceable transversely with respect to the rocking direction (arrow 30 in Fig. 3), and which can be held in two different positions in the counter-abutment 27 by means of a detent element 32. In the view shown in Fig. 7 the free end 33 of the pin projects into the operating region of the chain 7 of the feed or transporting apparatus, so that the counterabutment 27 can become operatively connected by means of pin 31 with the transporting apparatus. In the withdrawn position of the pin 31 the counter-abutment 27 is disengaged relatively to the transporting apparatus 7.

Secured on the chain 7 of the transporting apparatus is an abutment 34 which can become operatively connected with the counter-abutment 27 on movement of the abutment 34 in the direction of the arrow 35 and rocks the counterabutment 27 until it is against the abutment screw 29. When this happens, as will be described in more detail hereinafter, the locking brake 26 is released so that the washing apparatus 10 is made to travel in the direction of the arrow 35 by means of the transporting apparatus 7. As soon as the transporting apparatus is reversed in its transporting direction and moves in the direction opposite to the arrow 36, the counter-abutment 27 swings back again and the washing apparatus is held fast in the position reached on the press frame by the locking brake.

The entrainment means 36 is secured on the transporting apparatus before the abutment 34 as viewed in the direction of the arrow 35. As Fig. 3 shows, the spacing between the abutment 34 and the elements of the entrainment means 36 is so dimensioned that the counter-abutment 27 returns to its position of rest as soon as the projection 2 of the filter plate 3' to be cleaned is engaged by the elements of the entrainment means 36.

Since in the illustrated example of construction of the washing apparatus 2 there are provided parallel nozzle pipes 1 9 whose nozzles are directed towards one another, for the washing operation the filter piate to be cleaned must be displaced by the transporting apparatus 7 into the washing position 3" shown by broken lines. The washing position 3" is fixed not by the press frame but by the washing apparatus 10, so that in this transporting operation the entrainment means 36 has to be stopped precisely in the location in the opening gap with is present by the washing apparatus 10.Then since on movement of the transporting apparatus in the direction opposite to the arrow 35 the washing apparatus is held fast by means of its locking brake in the position shown in Fig. 3 in relation to the opening gap, the abutment 34, which is secured on the chain at a preset spacing relatively to the entrainment means 36, moves in the same direction as the filter plate 3' to be cleaned. Now, a stop switch 37, preferably a switch operating without physical contact, is secured on the carriage of the washing apparatus and is actuated by the abutment 34 on movement in the direction oppositely to the arrow 35 and which is connected to the drive of the transporting apparatus 7. As soon as the stop switch 37 is actuated by the abutment 34, the transporting apparatus with the filter plate in engagement with the entrainment means 36 at the time is stopped.The distance between the end position of the abutment 34 on the counter-abutment 27 and the stop switch 37 is so dimensioned that, with the actuation of the switch 37, the filter plate to be cleaned stops in the washing position 3". Then, by means of the suitability programmed control system of the plate filter press the drive for the travelling slide can be switched on and at the same time the pressure water valve for the nozzle pipes can be opened, so that the filter plate is cleaned from both sides with two rungs of the nozzle pipes over it.As soon as the travelling slide 16 has reached its upper basis position again, by means of a suitable further control signal, which is initiated for example by means of a limit switch not shown here which cooperates with the travelling slide, the drive for the transporting apparatus is switched on again, so that the filter plate which has now been cleaned can be moved further in the direction towards the head plate 5 and pressed there against the growing filter plate group. In this movement the abutment 34 passes a control switch 38 whereby a locking circuit for the actuation of the travelling slide 16 is released.This ensures that only on displacement of the cleaned filter plate beyond the distance preset by the control switch 38 is the opening gap between the two groups of filter plates free, and thus the next washing operation can be initiated without causing operational disturbances.

After the filter plates shown in Fig. 3 on the right beside the washing apparatus has been cleaned in this way, plate after plate, the pin 31 is withdrawn (Fig. 7), so that an operative connection between the transporting apparatus and the washing apparatus is no longer possible.

Then by means of an additional lever 39 the locking brake can again be released by hand and the washing apparatus moved into a position of rest at one end of the plate filter press, so that after the filter plate groups has been pushed together against the end plate 4 and the plate group closed with a suitable hydraulic pressure, a new filtration operation can be started.

Whereas in Fig. 3 abutment 34 and counterabutment 27 are shown in engagement with one another, as occurs directly after the reversal of movement of the transporting apparatus 7, in the larger-scale view in Fig. 4 the position of the abutment 34 is shown in relation to the washing carriage when the filter plate being cleaned is in the washing position 3" i.e. at the instant when the abutment 34 has actuated the stop switch 37.

The larger-scale view in Fig. 4 shows a further' safety switch. This comprises for example a pickup 40 with inductive or capacitive operation, which is arranged in stationary manner on the outer side of the carriage and with which there is associated a latch 41 also pivotably mounted on the carriage. A lever 42 is securely connected to the said latch 41 at that side of the carriage which is nearest the entrainment means, and is so aligned that the latch 41 is moved towards the pickup 40 when that part 43 of the transporting apparatus which engages the filter plate to be transported has run under the projection 2 of said plate and has taken up its transporting position.By means of this control switch, through the agency of an appropriate locking circuit acting at least on the drive of the travelling slide on the washing apparatus, the operations of the control apparatus which are subsequently required are allowed to occur, so that the transporting of the filter plate to be cleaned and also the movements of the nozzle pipes can proceed. But is the entrainment element 34 does not engage behind the projection 2 of the particular filter plate to be transported in the group of plates to be cleaned when the return travel is occurring in the direction of the arrow 35, the safety switch 40, 41, 42 is not actuated and the electrical locking system is not released, so that all further switching or control operations are blocked until the fault has been investigated.If necessary, the safety switch 40, 41, 42 can also be connected with a warning or signalling apparatus.

Details of the locking brake are shown in the view on a larger scale in Fig. 4 and in the section views on an even larger scale which are shown in Figs. 5, 6 and 7. The locking brake comprises substantially a bearing bracket 44 which is arranged laterally on the carriage and on which a brake shoe 45 is pivotably connected. The free end of the brake shoe 45 is provided at its upper side with a brake lining 46. The brake shoe 45 is pressed against the under edge of the rail 8 for the washing apparatus with the use of guide pins 47 and suitably hard springs 48.

The counter-abutment 27 constructed as a lever is also pivotably mounted on the supporting plate 25 by means of a bearing pin 49. The lever 27 is pivotably connected by means of a connecting rod 28 to an actuating lever 50 which at its lower end is held on the supporting plate 25 to be pivotable about a pivot pin 51 in the same plane of movement. The actuating lever is approximately T-shaped in construction and is provided at its two free ends with adjusting screws 52, 53 which can act with spacing relatively to the pivot bearing 54 on the upper side of the brake shoe 45. The adjusting screws 52, 53 are so set that the brake shoe 45 abuts on the rail 8 with the full application pressure force applied by the springs 48, but between the screw tips and the upper side of the brake shoe there is substantially no clearance.Then if the abutment 34 rocks the lever 27 in the direction of the arrow 55, the adjusting screw 53 presses the brake shoe downwardly, so that the locking brake is released.

The pivoting travel of the lever 27 is adjustable by means of an adjusting screw 29, so that the brake can be released with only a minimum pivoting distance. As soon as the lever 27 comes to abut on the abutment screw 29, the lever 27 serves substantially as an entrainment element for the abutment 34, so that the force effective from the abutment 34 in the direction of the arrow 35 is transmitted as a transporting force to the washing apparatus. Then as soon as the direction of movement of the transporting apparatus is changed-round, under the influence of the springs 48 the lever 27 moves back into its basic position, the brake shoe again coming to abut on the rail and the washing apparatus secured relatively the press frame.If the lever 27 is operated in the direction oppositely to the direction of the arrow 55 by hand the brake show is released by the adjusting screw 52, so that the washing carriage can then be displaced manually oppositely to the direction of the arrow 35 on the press frame to the end of the press frame into its initial position, until cleaning of the filter plates again becomes necessary. Then the washing carriage is moved from the rest position, which is usually at the end of the press frame on which the hydraulic cylinder 6 is also situated, by the plate transporting apparatus through the agency of the abutment 34 until the washing position is reached for the cleaning of the first filter plate. Figs. 8, 9 and 10 show in a side view (seen in the direction of the arrow A in Fig. 2) various arrangements for the nozzle pipes.Fig. 8 shows the same nozzle pipe arrangement as in Fig. 3. The positions of the end plate 4 and of the head plate 5 are shown in broken lines for easier understanding. In this constructional arrangement the nozzle pipes 19 are arranged on the travelling slide 16 on two holding arms arranged parallel adjacent one another. The nozzles 20 are directed with their openings towards one another. Spray shield plates or bruches 56 directed towards the filter plate being cleaned are arranged one above and one below each of the two nozzle pipes.Since the combination of filter plate transport and washing apparatus travel explained hereinbefore allows very precise positioning of the filter plate to be cleaned in relation to the washing apparatus, the spray shield plates or bushes can be taken in each case close up to the surface of the filter plate to be cleaned, so that optimum protection against splashing and unwanted spray is achieved.

Since furthermore with nozzles directed towards one another one filter plate surface may sometimes be subjected to stronger spraying pressure because of pressure differences, there are conveniently arranged on the holding arm 18, at the side facing towards the travelling slide, above and below the nozzle pipes 19, two supporting parts 57, 58 which are directed towards one another, the spacing of each two mutually opposite supporting parts 57, 58 being only slightly greater than the thickness of the filter plate to be cleaned. Then if the force of the water jets acting on the filter plate surface to be cleaned is greater at one side than at the other, these supporting parts prevent the filter plate from tilting about its supporting point on the guide bars.

Since two supporting parts 57, 58, in each case are arranged above one another at each side, it is also ensured that the filter plate cannot tilt over under the pressure of the water jets even when in the downward movement the lower supporting part 57 and in the upward movement the upper supporting part 58 is situated at the height of the supporting plane of the filter plate being cleaned.

In the constructional form according to Fig. 9 two nozzle pipes 19 are again arranged, but their nozzles 20 are directed outwards. In this nozzle pipe arrangement the arrangement of the stop switch 37 and of the safety switch 32 described in connection with Figs. 3, 4 is dispensed with, so that after the entrainment means latches on to the filter plate to be cleaned the said plate is moved over the full extent of the opening gap to the other side. As will easily be seen from Fig. 9, cleaning is effected by moving the nozzle pipes in the opening gap in each case, the front side of one filter plate and the rear side of the other filter plate being cleaned at the same time.The rest of the movement pattern, more particularly the moving of the washing apparatus in dependence on the varying position of the opening gap, in relation to the press frame, corresponds to that previously described. Appropriate spray shield plates or brushes 56 are provided again in this arrangement also.

In the constructional form shown in Fig. 10 only one nozzle pipe 19 is secured on the travelling slide 16, but said pipe comprises nozzles 20 directed to both sides. Whereas in the previous constructional examples an opening gap was used which corresponded to the normal, maximum possible opening gap of the filter plate group, in the constructional form according to Fig. 10 the washing operation works with a shortened opening gap. This means that the displaceable head plate 5 is not fully withdrawn for the washing operation, and instead is moved back only over about half the possible opening distance.

Otherwise the pattern of movement in the matter of the washing operation is carried out as in the constructional form of Fig. .9. In this way it is possible even with only one nozzle pipe to clean the surfaces of the filter plates bounding the opening gap by travel within the opening gap, since the minimum possible spacing from the nozzle openings can be maintained.

Fig. 11 shows a preferred constructional form for the entrainment means. The alignment of this entrainment means relatively to the end plate 4 or to the head plate 5 respectively is shown by illustrating these simply in a sketchy manner, for easier comprehension. Thus, the return travel takes place in the direction of the arrow 59, whereas the transporting travel takes place in the direction of the arrow 60. In the constructional form the transporting apparatus consists, as in the case of the preceding examples, of a flat link chain or roller chain 7. The entrainment means shown in Fig. 11 comprises substantially an entrainment element 62 pivotable connected to the chain 7 by means of a pin 61, and comprising a nose 63 at its side facing towards the projections 2 of the filter plates to be transported.The length of the nose 63 is so dimensioned that is projects above the guide plane of the guide bars 1 on which the noses 2 of the filter plates lie, so that the nose 63, as shown in Fig. 1 can be brought to abut on a nose 2.

In a mirror-image relationship relatively to the entrainment element 62 there is pivotably connected to the chain by means of a pin 64 a securing element 65. The pivoting travel of the entrainment element 62 and the securing element 65 is limited in both directions by apertures 66 and a pin 67 secured to the chain. The securing element 65 is pressed upwardly by a leg spring 68. The leg spring 68 at the same time presses against a bellcrank lever 70 which is pivotably mounted on the securing element 65 for pivoting about a pin 69 and which with its upper leg 71 projects above the guide edge of the guide bar 1 and with its lower leg 72 projects into the region of the entrainment element 62 and can be applied there against a pin 73.

Also arranged on the entrainment element is a retaining element 74 which is provided with a slot 75 and is held by a pin 75'. The end of the retaining element directed towards the nose 63 also has a nose 76, but the latter is in its effect directed oppositely to the nose 63. The retaining element is also secured at its rear end to the chain 7 through the agency of a preloaded spring 77.

The entrainment means operates as follows: At the return travel of the transporting apparatus, i.e. a movement in the direction of the arrow 59, the retaining element 74 is drawn by the spring preload against the pin 75', so that the nose 76 is pivoted below the guide plane and the nose 79 of the retaining element 74 above the guide plane of the guide bar 1. In this way the retaining element can run under the projection 2 of the filter plate to be transported. Next the upstanding nose 79 comes to abut on the projection 2 and pivots the retaining element 74 and the pin 75' into the plane shown in Fig.11, whereat the nose 76 then comes to abut on the projection 2'. The spring 77 is then preloaded, and with this preload force the group of plates is pressed against the end plate 4.On further movement of the transporting chain 7 in the direction 59 the nose 63 of the entrainment lever 62 comes to abut on the projection 2 with the shallow-sloping surface, whereat the element 62 is then pivoted downwards about the pin 61.

When this happens, the bellcrank lever 70 is rocked by means of the pin 73, so that the nose 71 swings forwards and as soon as this nose 71 come to abut on the projection 2, the bellcrank lever 70 and via the pin 73 the entrainment element 62 are swung back into the entrainment position.

Then as soon as the abutment surface 78 of the securing element 65 comes to abut on the projection 2 of the filter plate to be transported, the direction of movement of the chain is reversed, for example by a pressure-dependent reversing device, so that the chain then moves in the direction of the arrow 60 and can move the filter plate associated with projection 2 in the manner described hereinbefore into the washing position and then to the group of filter plates being built up at the head plate 5. In the first phase of the transporting movement i.e. when the filter plate 2 to be transported is detached from the plate group, the other plates are held pressed together by means of the nose 76 of the retaining element 74, thus ensuring that only one filter plate detaches from the group.

Because of the pivoting movement of the nose 63 of the entrainment element 62 as described already, the control switch 40, 41, 42 described in connection with Fig. 4 is actuated, and in fact by actuation of lever 42 of the control switch. This ensures that a washing operation can be initiated only when the nose 63 has been pivoted upwardly in the transporting position. But on the other hand this pivoting operation is possible only when the bellcrank lever 70 is pivoted upwardly when the projection 2 of the plate to be transported is encountered. The arrangement according to Fig.

11 also shows that during the transporting operation the projection of the filter plate to be transported is held positively by the entrainment means, so that the plate cannot move further under the influence of its inertia forces when the transporting apparatus stops. Thus it is ensured that the filter plate can be stopped with the requisite precision in relation to the washing apparatus in the washing position, and the correct nozzle spacings can be maintained, for example when using a nozzle pipe arrangement according to Fig. 8.

In Fig. 12 a plate filter press has filter plates arranged in suspended manner on a guide support 80 situated above the filter plates 3. The construction and the manner of operation of a plate filter press of this kind is known, so that there is no need here to explain the construction in detail. Here again the transporting apparatus 81 comprises preferably an endless roller chain 82 which is mounted above the filter plate suspension arrangement on the guide support, and the entrainment means 83 thereof which in construction corresponds to the entrainment means described in connection with Fig. 11 simply with the difference that the projections 84 of the filter plates are directed upwardly and the noses of the individual parts of the entrainment means, which noses come into operative connection with the projections, are correspondingly directed downwardly.The washing apparatus 85 comprises a carriage 86 which is held to be mobile on the upper side of the guide support 80 and on which there is arranged a guide member 87 extending laterally about the filter press, the free end of said member being supported by means of a roller 88 on a suitable supporting rail 89 in the lower region of the filter press. In the guide member there is correspondingly guided a travelling slide with a pivotable nozzle pipe, but the construction thereof is known, so that there is no need to describe the details here. Instead of a guide member at one side it is also possible to provide a supporting structure which extends about the filter press at both sides in a substantially gantry-like manner and is supported by means of the carriage 86, and in which one or more nozzle pipes, horizontally directed, are held so as to be mobile upwardly and downwardly.In the position of rest the spraying pipe remains below the plate group, so that the plates can be moved past the spraying pipes for the individual working phases of the filter press.

The carriage 86 is constructed in the same way as the carriage described in connection with Figs.

3 and 4, and is also provided with a locking brake 90. In the simplest form here again an abutment can be arranged on the roller chain in a "leading" situation relatively to the entrainment means, there being associated with said abutment a rocking lever extending suitably far downwardly for the purpose of releasing the brake and for the moving of the washing apparatus. But as a rule this kind of plate filter press is intended for large volumes and is consequently of correspondingly long construction. In such cases it is necessary to support more particularly the upper tie members 91 against bending stresses. This is usually achieved by one or more supporting plates or cross-members using the guide support 80. As a result the plane between washing carriage 86 and entrainment means 83 is interrupted, so that the simple construction mentioned hereinbefore can no longer be used.Now since, in this construction, direct action of the transporting apparatus i.e. the roller chain 82 in this case, is not possible for space reasons there is provided above the transporting apparatus an endless traction means 92 whose lower run extends parallel to the upper run of the chain 82 and at only a small spacing therefrom, and whose upper run is taken along the upper side of the guide support 80. Arranged on the lower run is an entrainment element 93 which can co-operate with a corresponding matching or counter-element 94 on the upper run of the chain 82. Since the transporting travel of the transporting apparatus occurs in the direction of the arrow 95, when the group of plates situated at the left of the washing apparatus 85 is opened the opening gap migrates with each plate transporting operation in the direction opposite to that of the arrow 95.The washing apparatus must also be moved stepwise from right to left accordingly. And accordingly there is secured on the upper run of the traction means 92 an abutment 96 which can co-operate with the counter-abutment 97 of the locking brake 90, which counter-abutment is again constructed as a lever, so that the movement of the washing apparatus by the traction means 92 is brought about through the agency of the two inter-engaging entrainment elements 93 and 94 and the abutment 96 likewise the counter-abutment 97, with release of the brake. In the same way as the constructional form described in connection with Figs. 3 and 4, by mechanical coupling with the transporting apparatus the washing apparatus can be moved stepwise in accordance with the displacement of the opening gap in the washing process. By suitable arrangement of stop, control and safety switches on the carriage 86 it is possible here again by means of the abutment 91 to achieve precise positioning of the filter plate to be cleaned in relation to the washing apparatus.

Instead of the mechanical operative connection described hereinbefore between the entrainment means 82, 83 and the washing apparatus, it is possible to arrange for the entrainment elements 93, 94 contact makes operating without physical contact, whereby a separate drive for the traction means 92 at each return travel of the transporting apparatus is actuated, in the same operational relationship.

Claims

1. A plate filter press comprising a plurality of vertically aligned filter plates mounted so as to be horizontally displaceable on at least one guide support of a press frame, each filter plate being provided with at least one projecting member, transport means comprising a member which is adapted to be driven reciprocably lengthwise of the press frame and supporting an engaging means which is adapted to cooperate with the projecting member of a filter plate to be transported; a washing device moveable longitudinally of the press operable to clean the filter plates, said washing apparatus having at least one nozzle pipe adapted to move transversely to the longitudinal axis of the press in a gap between separated filter plates; a brake having an operable position in which it can prevent the movement in the longitudinal direction of the washing apparatus, actuating means operatively associated with the transport means so as to release the locking brake and cause the washing apparatus to move in a direction towards a filter plate or set of filter plates to be cleaned, when the transport means is moving in one longitudinal direction of the press frame.

2. A plate filter press according to Claim 1, wherein the transporting means comprises at least one driven endless guided traction means on which the engaging means is secured; a first abutment being secured on the traction means spaced, lengthwise of the press frame, from the engaging means, the first abutment being engageable with a second abutment connected to the washing apparatus, the second abutment being operatively connected to the brake so as to effect the release thereof when engaged by the first abutment, and providing a driving connection between the washing apparatus and the traction means when engaged by the first abutment.

3. A plate filter press according to Claim 2, wherein the first mentioned abutment is located on the traction means ahead of the engaging means when considered in the direction of movement of the engaging means towards a filter plate or plates to be cleaned.

4. A plate filter press according to Claims 1. 2 or 3, wherein the second abutment comprises a pin by which the first abutment can engage the second abutment, said pin being displaceable whereby said engagement can be avoided.

5. A plate press according to any one of the preceding claims wherein means are provided for urging the brake contact with a complementary braking surface.

6. A plate filter press according to any one of the preceding claims, in which the washing apparatus is mounted on a rail secured to the press frame for longitudinal movement with respect to the press, and the locking brake is arranged to brakingly engage a surface of said rail.

7. A plate filter press according to any one of claims 1 to 6, in which the washing apparatus comprises a carriage member of the washing apparatus on which is mounted the second abutment and a switch arranged between the second abutment and a nozzle pipe holder, which switch is actuatable by the first abutment so as to switch off the drive of the transporting apparatus when the filter plate in engagement with the engaging means is at a predetermined washing position.

8. A plate filter press according to Claim 7, including means for driving nozzle pipes during a filter plate cleaning operation and a control circuit for actuation of said driving means, and a switch mounted on the carriage which is actuated by the first abutment to enable said control circuit for a subsequent cleaning operation only when a cleaned filter plate has been displaced by a predetermined distance from the position in which it was cleaned.

9. A plate filter press according to Claim 7 or 8, wherein there is arranged on the carriage a switch which is actuatable by that portion of the engaging means which drivingly engages the filter plate to be transported and which is operatively connected with a control circuit at least for the nozzle pipe drive.

10. A plate filter press according to any one of claims 1 to 9, wherein the press frame has two lateral guide bars on which the filter plates are guided by means of the laterally protruding projections and are displaceable by means of transport means laterally located with respect thereto, and wherein the washing apparatus is moveable in the longitudinal direction of the press on rails arranged laterally of the guide bars, the washing apparatus having a vertical guide member whose lower end is connected to a carriage running on one of the said lateral rails, a travelling slide connected to drive means and guided on the vertical guide member for movement upwards and downwards, the travelling slide being connected to a downwardly angled holding arm on the free end of which at least one horizontally directed nozzle pipe is secured.

11. A plate filter press according to claim 10, the vertical guide member is supported by means of a supporting arm provided with a roller on a rail secured on the guide bar.

12. A plate filter press according to claim 10 or 11, wherein spray shield plates and/or brushes are situated above and below the nozzle pipe, said plates or the like being directed towards the filter plate being cleaned.

13. A plate filter press according to claims 10, 11 or 12, wherein two nozzle pipes are arranged on the holding arm with their nozzle openings directed towards one another and there are situated respectively above and below the nozzle pipes supporting parts which are directed towards the filter plate being cleaned, and the spacing between each two mutually opposite supporting parts is slightly greater than the thickness of the filter plate to be cleaned.

14. A plate filter press according to any one of claims 1 to 9, whose press frame has at least one guide support on which the filter plates are guided in suspended fashion, and wherein the transporting apparatus is mounted on the guide support, and wherein the carriage of the washing apparatus is guided on the guide support, and wherein the carriage is connected to a traction means which is situated above the chain of the transporting apparatus and is guided along an endless path of travel and whose lower run extends parallel to the upper run of the chain of the transporting apparatus, and which is provided in the region of the carriage with an abutment acting on the counter-abutment of the locking brake and at its lower run in the region of the upper run of the chain of the transporting apparatus with an entrainment element, and that on the upper run of the chain there is secured a further entrainment element associated with the entrainment element on the traction means.

15. A plate filter press substantially as described herein with respect to Figs. 1 to 11 or Fig. 12.