GB2114908A - Filter press - Google Patents

Abstract

A filter press has cloths 16 arranged to be wound in the manner of roller blinds from their working position between the press plates on to spring-loaded rollers 20 when the press is open. As the cloths are so wound they pass between pairs of closely spaced blades 23, which remove the filter cake 30 from the cloths without damage thereto. The cloths are also washed by spray tubes 27, 28. <IMAGE>

Description

SPECIFICATION Filter press The present invention generally relates to a filter press arranged to separate a raw liquid to be processed, into a filtrate or filtered liquid and residue through filtering or press filtering thereof, and more particularly, to a filter press equipped with an improved residue separating arrangement for filter cloths used for respective filter plates or press filter plates of the filter press.

Conventionally, in a filter press of filter cloth travelling type, in order to collect filter residue adhering to a filter cloth via filtering of a mw liquid therethrough upon opening or spacing of filter plates for the filter press, there has been known an arrangement in which the filter residue as described above is adapted to be rubbed off the filter cloth by bringing a residue separating member such as a scraper or the like into contact with the surface of the filter cloth curved along a take-up roller for taking up the filter cloth or surface of a guide roller for guiding the filter cloth onto said take-up roller.

However, in the known arrangement as described above, in the case where the filter residue is scraped off the filter cloth by the scraper, etc., since the scraper is adapted to separate the residue while rubbing against the surface of the filter cloth between the residue adhering to the filter cloth and the filter cloth as said filter cloth is caused to travel, the surface of the filter cloth tends to be damaged by the scraper, thus resulting in a short life of the filter cloth.

Accordingly, an essential object of the present invention is to provide an improved filter press which is so arranged that a filter residue separating member constituted by a pair of platelike members to define a slit passage for passing a filter cloth therethrough is provided between a pair of support frames fixedly disposed below each of filter plates of the filter press, while a wedge-like edge portion is formed along an upper side of one of the plate-like members of the filter residue separating member so that the filter residue may be smoothly separated from the filter cloth without any damage to the surface of said filter cloth.

Another important object of the present invention is to provide a filter press of the above described type in which the slit passage formed between the plate-like members of each of the filter residue separating members is arranged to be positioned in or aligned with a travelling path of the filter cloth directed downwards generally in a vertical direction during opening of the filter plates, i.e. during travelling of said filter cloth so that any overload may not be applied to the filter cloth during its travelling for protecting the filter cloth against abrasion still positively so as to separate the residue adhering to the filter cloth in an efficient manner.

In accomplishing these and other objects, according to one preferred embodiment of the present invention, there is provided a filter press for separating raw liquid into a filtrate and filter residue, which includes a plurality of filter plates each having a pair of spaced support frames at the lower portion thereof and movably mounted between support stands for selective spacing therebetween or clamping together to each other, a pair of filter cloths disposed between each set of the neighboring filter plates, a winding up means arranged to be driven for a forward or reverse rotation, cord members directed around said winding up means and respectively connected to upper edges of said filter cloths for selective lowering of said filter cloths into between the respective neighboring filter plates or lifting said filter cloths therefrom, and a filter cloth take-up roller journalled between the spaced support frames of each of said filter plates and engaged with the lower edges of said filter cloths to be wound thereonto and to hold each of said filter plates therebetween. The filter cloth take-up roller is provided therein with a torsion spring arranged to urge the filter cloth take-up roller in a direction to wind up the filter cloths thereonto. The filter press further includes, a pair of filter residue separating members each having a slit passage for passing the filter cloths therethrough so as to separate the filter residue adhering to said filter cloths and provided between the spaced support frames of each of said filter plates.

By the arrangement according to the present invention as described above, an improved filter press efficient in operation has been advantageously presented through simple construction, with substantial elimination of disadvantages inherent in the conventional filter presses of this kind.

These and other objects and features of the present invention will become apparent from the following description taken in conjunction with the preferred embodiment thereof with reference to the accompanying drawings, in which: Fig. 1 is a schematic front elevational view of a filter press according to one preferred embodiment of the present invention, Fig. 2 is a cross section taken along the line Il-I I in Fig. 3 showing a rear side view of the filter press of Fig. 1, Fig. 3 is a fragmentary front elevational view of an essential portion of the filter press of Fig. 1, particularly showing the filter plates in an opened or spaced state, Fig. 4 is a fragmentary rear side view showing, on an enlarged scale, an essential portion in Fig. 2, Fig. 5 is a fragmentary cross sectional view showing, on an enlarged scale, detailed constructions in the arrangement of Fig. 3, Fig. 6 is a view similar to Fig. 1, which particularly shows a modification thereof, Fig. 7 is a cross section taken along the line VIl-VIl in Fig. 8 showing a rear side view of the filter press of Fig. 6, Fig. 8 is a fragmentary front elevational view of an essential portion of the filter press of Fig. 6, particularly showing the filter plates in an opened state, Fig, 9 is a fragmentary rear side view showing, on an enlarged scale, an essential portion in Fig. 7, Fig. 10 is a fragmentary front elevational view showing, on an enlarged scale, an essential portion in Fig. 8, Fig. 11 is a fragmentary cross section taken along the line Xl-Xl in Fig. 9, Fig. 12 is a fragmentary cross sectional view showing, on an enlarged scale, the filter plates employed in the filter press of Fig. 6 in a closed or clamped state (represented by A in Fig. 12) and in an opened state (represented by B in Fig. 12), Fig. 13 is a fragmentary cross sectional view showing a modification of a residue separating member of Fig. 11, Fig. 14 is a fragmentary cross sectional view showing, on an enlarged scale, an essential portion of a filter press employing the modified filter residue separating member of Fig. 13, Fig. 15 is a view similar to Fig. 6, which particularly shows a further modification thereof, Fig. 16 is a cross section taken along the line XVl-XVl in Fig. 17 showing a rear side view of the filter press of Fig. 1 5, Fig. 17 is a fragmentary front elevational view of an essential portion of the filter press of Fig. 1 5, particularly showing the filter plates in an opened state, Fig. 18 is a fragmentary rear side view showing on an enlarged scale, an essential portion in Fig. 16, Fig. 19 is a fragmentary cross sectional view showing, on an enlarged scale, an essential portion in the arrangement of Fig. 17 (in the filter plate at the left side in Fig. 19, the cross section taken along the line XlX-XIX in Fig. 18 is shown at the right side of a line S-S, while the cross section taken along the line XlX'-XIX' in Fig. 18 is given at the left side of the line S-S), and Fig. 20 is a fragmentary cross sectional view showing the filter plates of the filter press of Fig. 15 in the closed or clamped state, Figs. 21 and 22 are views similar to Fig. 20, which particularly show further modifications thereof, and Figs. 23 through 27 are also views similar to Fig. 20, which particularly show still further modifications thereof.

Before the description of the present invention proceeds, it is to be noted that like parts are designated by like reference numerals throughout the accompanying drawings.

Referring now to the drawings, there is shown in Figs. 1 and 2, a filter press FA according to one preferred embodiment of the present invention.

The filter press FA generally includes a front stand 1 for supporting a carrier plate 2, and a rear stand 3, which are mounted on a suitable base F in a spaced relation from each other, side beams 4 respectively provided at opposite sides of the front and rear stands 1 and 3, a plurality of filter plates 5 connected to each other by connecting links 6 provided at opposite sides thereof, and slidably supported on upper edges of the side beams 4 through a pair of protrusions 5a formed on opposite sides of each of the filter plates 5 for movement in a lateral direction in Fig. 1, and a movable plate 7 arranged to be driven by a driving piston 8 of a hydraulic means or the like (not shown), supported by the rear stand 3 for reciprocation in the lateral direction, so that, upon retraction of said movable plate 7 back to a position R shown by dotted lines, the respective filter plates 5 are opened or spaced from each other at a predetermined intervals set by the connecting links 6.

The filter press FA of Fig. 1 further includes a pair of driving shafts 9 each having a polygonal cross section and suitably journalled in upper opposite sides of the front and rear stands 1 and 3 so as to be driven in a forward and a reverse direction for rotation by a motor 13 having a reduction unit mounted on a fixing base 12 provided at the upper portion of the rear stand 3, through a bevel gear transmission mechanism 14.

As shown in Fig. 2, the driving shafts 9 are respectively fitted in corresponding pairs of winding up or take-up pulleys 11 rotatably supported at upper opposite sides of the filter plates 5 through support members 10 secured to the upper portions of said filter plates 5. Around each of the winding up pulleys 11, a hanger cord 1 5 is directed, with one end of the hanger cord 1 5 being connected to the pulley 11, while the other end of the cord 1 5 is connected to a connecting piece 18 fixed to each end portion of a hanging rod 17 for suspending a filter cloth 16 therefrom.

On the under surface of a frame for the filter plate 5, a pair of support metal pieces or frames 19 are provided to extend downwardly therefrom, while at the lower portions of said support pieces 19, another pair of auxiliary support metal pieces 22 are provided to rotatably hold a filter cloth take-up roller 20 therebetween.

As shown in Fig. 1 and Fig. 3, lower edge portions of two pieces of filter cloth 16-1 and 16-2, which respectively cover the front and rear filter faces 5b at opposite faces of the filter plate 5, are adapted to be fixedly engaged with the take-up roller 20.

As is most clearly seen in Fig. 4, the take-up roller 20 is composed of a cylindrical hollow roller, which is rotatably supported at its opposite ends through bearings by a support shaft 25 secured between the support metal pieces 19. Within the take-up roller 20, there is provided a coil-shaped torsion spring 26 whose opposite ends are engaged with said take-up roller 20, and the torsion spring 26 is wound around the support shaft 25, with the central portion of said spring 26 being secured to the support shaft 25, so that, the take-up roller 20 is normally urged by the spring force of the torsion spring 26, in a rotating direction along which the filter cloths 16-1 and 16-2 are wound.

Meanwhile, at the upper portion of the pair of support metal pieces 19 described earlier, there is mounted a filtering residue separating member 23 composed of a pair of plate-like members, i.e. an outer plate 23a and inner plate 23b.

The inner plate 23b is bent, at its upper portion, externally away from the filter plate 5 and is secured, at its opposite ends, to the support metal pieces 19. As shown in Fig. 5, the outer plate 23a has a wedge-shaped edge portion 23c formed at its upper edge and is longer in length than a width of the filter cloth 1 6. The outer plate 23a is detachably mounted, by bolts 31, on the outer side of the inner plate 23b, with a slit having a width approximately equal to the thickness of the filter cloth 16 being provided therebetween, and thus, a bent slit passage 32 is formed between the outer plate 23a and the inner plate 23b to allow the filter cloth 16 to pass therethrough.

Accordingly, during downward running of each filter cloth 1 6, the edge portion 23c of the outer plate 23a of the filter residue separating member 23 is cut into between the filter cloth 16 and the filter residue 30 adhering to the filter cloth 16, and therefore, the filter cloth 16 alone is caused to pass through said slit passage 32, with each face thereof being in sliding contact with the respective plates 23a and 23b, while the filter residue 30 is being separated from the filter cloth 16 due to the wedge effect caused by the edge portion 23c, and thus, the travelling path of the filter cloth 16 is adapted to be directed inwards.

Moreover, before the filter plate 5 and between the support metal pieces 19, in a position below the filter residue separating members 23, there are fixed shifting rods 21, with washing pipes 27 being provided under the shift rods 21. Each of the washing pipes 27 is provided, on its surface, with a large number of first nozzles 28a directed vertically upwards, and second nozzles 28b directed slantwise upwardly and projecting rearwardly. The filter cloth 16-2 at the rear side of the filter plate 5, the filter residue 30 of which has been separated by its passing through the slit passage 32 of the filter residue separating member 23, is further altered in its travelling path towards the front side of the filter plate 5 so that the filter cloth surface can be washed with washing water jetted from the first nozzles 28a.

On the other hand, the second nozzles 28b are adapted to wash the surface of the filter cloth 16-1 on the front side of the rearwardly located filter plate 5. Furthermore, water guard plates 29 are provided below the washing pipes 27 to protect the filter cloths 16 wound on the filter cloth takeup rollers 20 against splash of water with which the filter cloth have been washed.

By the above arrangement, as shown in solid line in Fig. 1, in a state where the filter plates 5 have been simultaneously clamped together to the side of the front stand 1 by the advance of the movable plate 7, raw liquid which has been poured under pressure between the filter cloths 16, through a raw liquid supply port 5c provided on each of the filter plates 5 (Fig. 2) and raw liquid supply fitting 1 6a attached to each of the filter cloths 16, from a raw liquid supply pipe 1 a supported on the front stand 1, is separated into the filter residue and the filtered liquid, with the filtered liquid being further collected through a filtered liquid collecting pipe 24 provided at the lower side portion of each of the filter plates 5.

Upon retreat of the movable plate 7 back to the position R in Fig. 1 after completion of one filtering process, the filter plates 5 which are successively coupled with each other from the side of the movable plate 7 by the connecting links 6 are simultaneously opened or spaced from each other at predetermined intervals as shown in Fig. 3.

Simultaneously with the opening or spacing of the filter plates 5 as described above, part of the separated filter residue 30 falls downwards by gravity as it is in a configuration of a cake. At a stage where some portion of the filter residue 30 has been dropped, the filter cloth 16 is kept spread so as to be slightly away from the filter plate 5. In this stage when the hanger cords 15 passed around the winding up pulleys 11 are rotated for rewinding via the right and left driving shafts 9 by driving the motor 13 in a rewinding direction through speed reduction of the motor 13, the torsion spring 26 in a fully twisted state causes the take-up roller 20 to rotate in a winding direction by its strong spring force.

The filter cloths 16-1 and 16-2 located at opposite faces of the respective filter plates 5 are passed through the corresponding filter residue separating members 23 by the winding rotation of the take-up roller 20 arising from the spring force of the spring 26, thereby to separate the filter residue 30 remaining on the filter cloths 16-1 and 16-2 therefrom. The filter cloth 16-1 at the front side of the filter plate 5 whose filter residue 30 has been separated, is wound onto the take-up roller 20, while being changed in its running path somewhat inwardly by the water guard plate 29.

On the other hand, the filter cloth 16-2 at the rear side of the filter plate 5 whose filter residue 30 has been separated is altered in its running passage, towards the front side by the shift rod 21, and thereafter, is wound, together with the filter cloth 16-1, onto the take-up roller 20. It is to be noted here that washing of each of the filter cloths 16 by water from the washing pipe 27 is properly effected during the filter cloth winding or filter cloth rewinding.

As is seen from the foregoing description, in the filter press according to the present invention, it is so arranged that the filter residue separating member composed of the pair of plate-like members having the slit passage formed therebetween for changing the travelling path of the filter cloth inwardly by passing said filter cloth therethrough, is provided between the pair of support metal pieces or frames provided below each of the filter plates, while the wedge-like edge portion is formed at the upper edge of one of the plate-like members of the filter residue separating member for contact with the front surface of said filter cloth, and therefore, during downward travelling of the filter cloth, it is possible to cause only the filter cloth to pass through the slit passage of said filter residue separating member, with the filter residue adhering to the filter cloth being smoothly separated from the filter cloth by said wedge-like edge portion at the entrance of said slit passage, while any damage to the filter cloth during separation of the filter residue therefrom may be positively prevented. Moreover, since the filter cloth can be guided by the slit passage, guide rollers or the like for the filter cloth may be dispensed with, thus resulting in a simplification in the structure at the lower portion of the filter plates.

Referring to Figs. 6 to 12, there is shown a modification of the filter press FA of Figs. 1 to 5.

The modified filter press FB of Figs. 6 to 12 is intended to further prevent the abrasion of the filter cloths by causing the slit passages of the filter residue separating members to locate along the downward travelling path of the filter cloths generally in the vertical direction, during opening of the filter plates, i.e. during travelling of the filter cloths, and is so arranged that the filter residue separating members are provided in pair to confront each other in positions above the filter cloth take-up roller supported between the pair of support metal pieces provided below the filter plates, with a spring expansible and contractible back and forth with respect to the filter plates being disposed between said filter residue separating members, whereby upon opening or spacing of said filter plates, the slit passages of the filter residue separating members are aligned with the downward travelling path of the filter cloths generally in the vertical direction, while upon closing or clamping together of the filter plates, the filter residue separating members are accommodated within the thickness of the filter plate through contraction of the spring.

In the modified filter press FB of Figs. 6 to 12, the filter residue separating members 23B each formed by the outer plate 23Ba and the inner plate 23Bb to define a slit passage 32B therebetween are provided in pair at the upper portion of the support metal pieces 19 through support members S.

The outer plate 23Ba is made of a thin plate longer in length than the width of the filter cloth 16, and is formed, at its upper edge, with a residue separating edge 23Bc which is inclined slantwise from the inner side towards the outer side with respect to the filter plate 5.

Meanwhile, the inner plate 23Bb is formed by a thin plate having the length approximately equal to that of the outer plate 23 Ba, and as shown in Fig.11, the outer plate 23Ba is secured to the inner plate 23Bb by the bolts 31, through thin plates P having approximately the same thickness as that of the filter cloth 16 and disposed on the outer surface at opposite ends of the inner plate 23Bb so as to define the slit passage 32B between the outer plate 23Ba and the inner plate 23Bb for passing the filter cloth 1 6 therethrough.

Moreover, as shown in Fig. 12, the inner plate 23Bb is formed, at its upper and lower edges except for the opposite ends thereof, with an upper edge portion e 1 and a lower edge portion e2 for the filter cloth, which are respectively inclined from the outer side towards inner side with respect to the filter plate 5, while, at said opposite end portions of each of the inner plate 23Bb, disc-like protrusions e3 for receiving springs W thereon, and engaging portions e4 axially extending from the opposite ends of the inner plate 23Bb in a stepped manner are provided.

Each of the support members S fixed, at its outer face, to the inner side of the support metal piece 19, is formed, at is inner face side, with a recess SV for movably receiving the above engaging portion e4 of the inner plate 23Bb in a back and forth direction of the filter plate 5.

Accordingly, the pair of the filter residue separating members 23B are disposed between the pair of supporting metal pieces 19 so that the inner plates 23Bb thereof confront each other, with the spring W being fitted between the disclike protrusions e3, and with the respective engaging portions e4 of the inner plate 23Bb being received in the corresponding recesses SV of the support members S (Fig.11). Thus, as shown at B in Fig. 12, upon opening or spacing of the filter plates 5, the respective engaging portions e4 as described above are brought into contact with the inner faces of the recesses SV of the support members S by the spring force of the springs W so as to position the slit passages 32B of the filter residue separating members 23B along the downward travelling path directed generally in the vertical direction for smooth running of the filter cloth 1 6, without any damage to the surface of the.filter cloth 16 by the edge portions 23Bc and el of the outer and inner plates 23Ba and 23Bb of the filter residue separating member 23B.Accordingly, during downward running of each filter cloth 16, the edge portion 23Bc of the outer plate 23Ba of the filter residue separating member 23B is cut into between the filter cloth 16 and the filter residue 30 adhering to the filter cloth 16 and therefore, the filter cloth 16 alone is caused to pass through said slit passage 32B with each face thereof being in sliding contact with the respective plates 23Ba and 23Bb, while the filter residue 30 are being separated from the filter cloth 16 due to the wedge effect caused by the edge portion 23Bc. On the other hand, as shown at A in Fig.12, during closing or clamping together of the filter plates 5, the outer plates 23Ba are pushed against each other for compressing the springs W within the thickness of the filter plate 5 so that there is no inconvenience for the clamping of the filter plates 5.

Furthermore, between the filter residue separating members 23B and the filter cloth takeup roller 20 supported by the support metal pieces 1 9, there are further journalled a first and a second guide rollers G1 and G2 for guiding the filter cloths 16 6 before and after each of the filter plate 5, while at the back of the filter plate 5 in a position between the guide rollers G1 and G2, the water washing pipe 27B having a large number of nozzles 28Ba upwardly extending slantwise rearwardly from said pipe 27B is provided for washing of the filter cloth 1 6.

In the filtering operation to be effected generally in the similar as described with reference to Figs. 1 to 5, the filter cloth 16-1 which is located at the front side of the filter plate 5, and from which the filter residue 30 has been separated, is wound onto the filter cloth take up roller 20 after being bent to a certain extent towards the rear side of the filter plate 5 by the second guide roller G2. Meanwhile, the filter cloth 1 6-2 located at the back of the filter plate 5 is also wound onto the filter cloth take up roller 20, through said first and second guide rollers G1 and G2, after sliding contact thereof with the lower edge portion e2 of the inner plate 23Bb of the filter residue separating member 23B.

In the modified filter press FB as described so far, since the slit passage 32B is formed by disposing the thin plates P between the outer plate 23Ba and the inner plate 23Bb of each of the filter residue separating members 23B, the width of the slit passage 32B may be readily altered by changing the thickness of the thin plates P for application to various filter cloths, in addition to the effects available from the first embodiment of Figs. 1 to 5.

The filter press FB described so far may further be modified in various other ways, for example, as in the filter press FC shown in Figs. 13 and 14. In the modified filter press FC, each of the inner plates 23Bb described as employed in the arrangement of Figs. 6 to 12, is replaced by a roller m so as to define a slit passage 32B' between said roller m and the outer plate 23 Ba.

More specifically, the opposite ends of each of the rollers m are journalled in L-shaped auxiliary members I, while a disc-shaped protrusion (not particularly shown) is formed at the inner surface of each of said auxiliary members I for receiving the spring W, with engaging portions C similar to the engaging portions e4 being provided at the end portions of the auxiliary members I for engagement with the recesses SV of the support members S so that the filter residue separating members 23B' each including the outer plate 23Ba and the roller m are movable in the back and forth directions with respect to the filter plates 5.

By the above arrangement, the travelling of the filter cloth 16 within the slit passage 32B' can be more smoothly effected through guiding by the roller m.

Since other constructions end effects of the filter presses FB and FC of Figs. 6 to 14 are generally similar to those of the filter press FA in Figs. 1 to 5, detailed description thereof is abbreviated for brevity, with like parts being designated by like reference numerals and symbols.

As is seen from the foregoing description, in the modified filter presses FB and FC of Figs. 6 to 14.

the filter residue separating members are provided in pair to confront each other in positions above the filter cloth take-up roller supported between the pair of support metal pieces provided below the filter plates, with the spring expansible and contractible back and forth with respect to the filter plates being disposed between said filter residue separating members so that upon opening or spacing of said filter plates, the slit passages of the filter residue separating members are aligned with the downward travelling path of the filter cloths generally in the vertical direction, while upon closing or clamping of the filter plates, the filter residue separating members are accommodated within the thickness of the filter plate through contraction of the spring, and therefore, the filter cloth may be positively protected against abrasion without any inconvenience for the clamping of the filter plates, while the filter cloth can be caused to travel very smoothly.

Reference is further made to Figs. 1 5 to 20 showing a further modification of the filter press FB of Figs. 6 to 12. The modified filter FD of Figs.

1 5 to 20 also has for its object to further prevent the abrasion of the filter cloth during separation of the filter residue therefrom, and is so arranged that the slit passage of the filter residue separating member for passing the filter cloth therethrough is also aligned with the downward travelling path of the filter cloth generally in the vertical direction so that no overload is applied to the filter cloth during travelling thereof for positively preventing abrasion of the filter cloth, while the filter residue adhering to the filter cloth may be positively separated.

In other words, in the modified filter press FD to be described hereinbelow, the filter residue separating member having the slit passage for passing the filter cloth therethrough is pivotally supported by a shaft provided at the upper portion of the filter cloth take-up roller journalled between the pair of support metal pieces, so that, upon opening or spacing of the filter plates, the filter residue separating member is pivoted by the filter cloth spread by urging force of the spring of the filter cloth take-up roller so as to align the slit passage with the downward travelling path of the filter cloth generally in the vertical direction, while, upon closing or clamping together of the filter plates, the filter residue separating member is again accommodated within the thickness of the filter plate.

In the modified filter press FD of Figs. 15 to 20, the filter residue separating members 23D each formed by the outer plate 23Da and the inner plate 23Db to define a slit passage 32D therebetween are provided in pair at the upper portion of the support metal pieces 1 9 through support rollers 23 or.

The outer plate 23Da is made of a thin plate of an approximately triangular cross section longer in length than the width of the filter cloth 1 6 and projecting out of the filter plates, and is formed, at its upper edge, with the residue separating edge 23Dc.

Meanwhile, the inner plate 23Db is formed by a thin plate having the length approximately equal to that of the outer plate 23Da, and has reduced thickness portions 23De formed at its opposite ends. Between the reduced thickness portions 23De and the corresponding end portions of the outer plate 23Da, thin plates P each having a thickness approximately equal to the thickness of the filter cloth 16 are respectively disposed so as to be fixed through brackets b, to a support roller 23Dr supported between the support metal pieces 19 for making it possible to cause the slit passage 32D having the width approximately equal to the thickness of the filter cloth 16 to be aligned with the downward travelling path of the filter cloth 16 generally in the vertical direction through pivotal movement of the support roller 23Dr for allowing only the filter cloth 16 to pass through said slit passage 32D.

Accordingly, the respective residue separating members 23D are pivotally supported by the support rollers 23Dr, with the inner plates 23Db thereof confronting each other between the support metal pieces 19 below the filter plates 5.

Thus, as shown in Fig. 19, upon opening or spacing of the filter plates 5, the filter residue separating members 23D are respectively pivoted in the directions of arrows together with the support rollers 23Dr by the spring force of the torsion spring of the filter cloth take-up roller 20 so as to align the slit passages 32D of the filter cloth separating members 23D with the downward travelling path of the filter cloth 1 6 generally in the vertical direction for causing the filter cloth 26 to travel very smoothly without being damaged by the upper edge 23Dc of the outer plate 23Da of the filter residue separating member 23D.

Therefore, in the downward running of each filter cloth 1 6, the edge portion 23Dc of the outer plate 23Da of the filter residue separating member 23D is cut into between the filter cloth 16 and the filter residue 30 adhering to the filter cloth 16, and thus, the filter cloth 16 alone is caused to pass through said slit passage 32D, while the filter residue 30 is separated from the filter cloth 16 due to the wedge effect caused by the edge portion 23Dc so as to be dropped slantwise downwardly through guiding by the edge portion 23Dc.

On the other hand, upon closing of the filter plates 5, the outer plates 23Da are pushed against each other, and rotate the residue separating members 23D together with the support rollers 23Dr in directions opposite to those indicated by the arrows in Fig. 19, while causing the filter cloth 1 6 to be bent into the thickness of the filter plate 5, and thus, accommodate the respective residue separating members 23D into the thickness of the filter plates 5 as shown in Fig. 20 so as to provide no inconvenience for the clamping together of the filter plates 5.

Furthermore, in positions below the support roller 23Dr provided between the support metal pieces 1 9, there are further journalled the first and the second guide rollers G1 and G2 for guiding the filter cloths 16-1 and 16-2 before and after each of the filter plate 5, while at the back of the filter plate 5 in a position between the guide rollers G1 and G3, the water washing pipe 27D having a large member of nozzles 28Da upwardly extending slantwise and rearwardly from said pipe 27D is provided for washing of the filter cloths 1 6.

It should be noted here that the arrangement described so far with reference to Figs. 1 5 to 20 may further be modified into various ways within the scope. For example, in the modified filter press FD as described in the foregoing, although the residue separating members 23D are provided above the support rollers 23 or, these separating members may be provided below said support rollers on the contrary.

Since other constructions and effects of the filter press FD as described so far are generally similar to those of the filter press FB or FC in Figs.

6 to 14, detailed description thereof are abbreviated here for brevity.

Referring further to Fig.21, there is shown a further modification of the filter press FA of Figs. 1 to 5. In the modified filter press FE of Fig. 21 , the filter residue separating members 23, shift rod 21, washing pipe 27, guard plate 29, etc. described as employed in the arrangement of Figs. 1 to 5 are replaced by first, second and third guide rollers G3, G4 and G5, and two washing pipes 27E provided between the spaced support frames 19 at the lower portion of each of the filter plates.

More specifically, in positions above the filter cloth take-up roller 20, the first, second and third guide rollers G3, G4 and G5 are supported between the support frames 1 9, with respective axes of said rollers G3, G4 and G5 being eccentrically arranged in a widthwise and vertical directions of the filter plate 5 through small intervals in the vertical direction therebetween as shown. The filter cloths 16-1 and 16-2 respectively covering the front and rear faces of the filter plate 5 are directed around the guide rollers G3, G4 and G5, and fixed, at the lower edges thereof, to the filter cloth take-up roller 20, so that the travelling path of the filter cloths 1 6-1 and 16-2 is bent still more inwardly than in the case where said filter cloths are stretched by the spring force of the torsion spring 26 of the take-up roller 20.In other words, the filter cloth 16-1 at the front side of the filter plate 5 is guided by the first guide roller G3 to the rear side of the filter plate 5 so as to be passed over the second guide roller G4, while the filter cloth 16-2 at the rear side of the filter plate 5 is guided together with the filter cloth 16-1 by the second guide roller G4 to the front side of the filter plate 5 for being further directed around the third guide roller G5 so as to be subsequently wound around the filter cloth take-up roller 20.

Accordingly, during the downward travelling of the filter cloths 16, the travelling path of said filter cloths is altered by the guide rollers G3, G4 and G5, so that between the first guide roller G3 and the second guide roller G4, a tension is applied to the front side filter cloth 16-1 so as to separate, at the first guide roller G3, the filter residue 30 from the filter cloth 16-1 based on a difference in inertia force between said filter cloth 16-1 and the filter residue 30 adhering to said filter cloth 16-1, while, between the second guide roller G4 and the third guide roller G5, a tension is also applied to the rear side filter cloth 1 6-2 so as to separate, at the second guide roller G4, the filter residue 30 from the filter cloth 16-2 by the difference of inertia force between the filter cloth 16-2 and the residue adhering to said filter cloth 16-2 and the residue adhering to said filter cloth 16-2 in such a manner as to draw said filter cloth 16-2 through the guide roller G4. The washing pipes 27E respectively provided below the first and second guide rollers G3 and G4 between the support frames 19 are arranged to wash the respective filter cloths 16-1 and 16-2 from which the filter residue 30 has been separated, with water discharged from the washing nozzles 28Ea extending upwardly from said washing pipes 27E.

It should be noted here that the arrangement in the filter press FE as described above may further be modified in various ways within the scope, for example, as in a modified filter press FF in Fig. 22.

In the filter press FF of Fig. 22, instead of commonly using the guide rollers for the front and rear side filter cloths 16-1 and 1 6-2 as in the filter press FE of Fig. 21, a first set of guide rollers G3-1 and G4-1, and a second set of guide rollers G3-2 and G4-2 are separately provided for the respective filter cloths 16-1 and 16-2 as shown.

By this arrangement, since the filter cloths 16-1 and 16-2 are not overlapped until they are wound onto the filter cloth take up roller 20, washing of the filter cloths by the washing pipes (not particularly shown in Fig. 22) may be more positively effected.

Since other constructions and effects of the filter presses FE and FF as described so far are generally similar to those of the filter press FA in Figs. 1 to 5, detailed description thereof are abbreviated here for brevity.

Reference is further made to Fig. 23 showing another modification of the filter presses as described so far. In the modified filter press FG of Fig. 23, between the support frames 19 for each of the filter plates 5, the filter cloth take-up roller 20 is journalled at the upper central portion, and at the lower opposite sides in the direction of thickness of the filter plate 5 with respect to said take-up roller 20, a pair of guide rollers G6 are supported, while, in the vicinity of the guide rollers G6 and in positions between the take-up roller 20 and the guide rollers G6, a pair of separating wires 23G are fixedly provided.

More specifically, the separating wires 23G as referred to above are provided in the positions where the filter cloths 16 extended in a natural state from the upper edges thereof to the guide rollers G6 by the spring force of the torsion spring 26 of the filter cloth take-up roller 20 are inwardly bent to a certain extent, so as to contact the surfaces of the filter cloths 16.During running of the filter cloths 16 to which the filter residue 30 adheres, the travelling direction of the filter cloths 16 running linearly, with the tension applied thereto by the torsion spring 26 of the take-up roller 20, is altered inwardly by the separating wires 23G, and based on the difference in the inertia force between the filter residue 30 and the filter cloths 16, small clearances t are produced between the filter residue 30 and the filter cloths 1 6 for smoothly effecting separation of the filter residue 30 from the filter cloths 16 by directing the separating wires 23G into said clearances t.

Although not particularly shown, between the lowest portions of the support frames 19 of each filter plate 5, the washing pipe similar, for example, to washing pipe 27 in Figs. 1 to 5 and having a large number of washing nozzles extending outwardly therefrom is provided to wash the filter cloth 16 from which the filter residue 30 has been separated.In other words, by the rotation of the take-up roller 20 through the spring force of the spring 26 thereof, the filter cloths 16-1 and 16-2 at the opposite faces of each of the filter plates 5 are wound onto said take-up roller 20 while being subjected to the change in directions through approximately 1 800, and when the filter cloths 16 pass the portion where the running direction thereof is inwardly altered by the separating wires 23G, the small clearances t are formed between the filter residue 30 adhering to the filter cloths 16 and said filter cloths for directing the separating wires 23G into said clearances t so as to separate the filter residue 30 from the filter cloths 16, with the filter residue 30 thus separated being collected through dropping thereof by its weight.

It should be noted that the filter press FG may also be further modified in various ways within the scope, for example, as in a filter press FH shown in Fig. 24.

In the modified filter press FH of Fig. 24, the separating wires 23G described as employed in the arrangement of Fig. 23 are replaced by platelike scrapers 23H each having an inclined surface 23Ha directed slantwise outwardly and downwardly at the upper ends thereof. By the above arrangement, the filter residue 30 separated from the filter cloths 16 may be more smoothly guided downward by the inclined surfaces 23Ha of the scrapers 23H so as to prevent collection of the filter residue 30 in the vicinity of the scraper 23Ha.

In a filter press Fl according to a still further modification as illustrated in Fig. 25, the guide rollers G6 are provided at the upper portion of the support frames,9, with the filter cloth-take-up roller 20 being provided below the guide rollers G6, while the scrapers 231 are respectively provided in the vicinity of the guide rollers G6 and in positions between said guide rollers G6 and the filter cloth take-up roller 20. By the above arrangement of Fig. 25, the travelling direction of the filter cloths 16 may be altered to a larger extent so as to further facilitate the separation of the filter residue 30 from the filter cloths 16.

Referring finally to Figs. 26 and 27 showing still another modification of the filter presses described so far, the modified filter press FJ includes the scrapers 23J pivotally supported by the support rollers 23Jr at the upper portion of the support frames 19. Each of the above scrapers 23J has a filter residue separating edge 23Ja pointed towards the sides of the support rollers 23Jr, i.e. towards the surfaces of the filter cloths 16 to which the filter residue 30 has adhered, and is made of a thin plate longer in length than the width of the filter cloth 1 6, while the opposite ends of the scrapers 23J are secured to said support rollers 23Jr through the brackets b.

From the peripheral surfaces at opposite ends of the support rollers 23Jr, L-shaped stoppers each folded towards the support frames 19 are extended at an equal phase with respect to the support rollers 23Jr, while contact members ffor stopping said stoppers j are respectively fixed to the support frames 19 so as to restrict the rotation of the support rollers 23J in the direction in which the edges 23Ja of the scrapers 23J secured thereto are spaced from the filter cloths 16.

Accordingly, the filter cloths 16 pass through space V formed between the support rollers 23Jr and the edges 23Ja of the scrapers 23J.

Thus, upon spacing or opening of the filter plates 5, the respective scrapers 23J are pivoted together with the support rollers 23Jr in the directions indicated by the arrows A in Fig. 26 by the filter cloths 16 stretched through the spring force of the torsion spring 26 (Fig. 4) of the takeup roller 20, and the stoppers j are respectively caused to contact the contact members f so as to align the edges 23Ja of the scrapers 23J with the downward running path of the filter cloths 16 generally in the vertical direction, whereby, by the cutting of the edges 23Ja of the scrapers 23J into between the filter cloth 16 and the filter residue 30 adhering to said filter cloth, the filter residue 30 is separated from the filter cloth 16 through the wedge effect by the edges 23Ja.

On the other hand, upon closing or clamping together of the filter plates 5, the scrapers 23J respectively provided to correspond to the neighboring filter plates 5 are pushed against each other so as to be pivoted in the directions indicated by the arrow B in Fig. 26, while bending the filter cloth 16 into within the thickness of the filter plate 5 so as to accommodate the respective scrapers 23J into the thickness of the filter plate 5 as shown in Fig. 27 for providing no inconvenience to the clamping of the filter plates 5.Moreover, below the support rollers 23Jr between the support frames 19, the first, second and third guide rollers G7, G8 and G9 are respectively journalled for guiding the filter cloths 16-1 and 16-2 provided before and after the filter plate 5, while at the rear side of the filter plate 5 between the second and third guide rollers G8 and G9, the washing pipe 27J having a large number of nozzles 28Ja extending slantwise upwardly therefrom is provided for washing of the filter cloths 16.

In the modified filter press FJ as described so far, the degree of contact of the edges 23Ja of the scrapers 23J with respect to the filter cloths 16 may be readily adjusted through variations of the positions of the stoppers f with respect to the support rollers 23Jr or through variations of the positions or widths of the contact members j in various ways. Moreover, such degree of contact may also be adjusted through urging the scrapers 23J in the direction to contact the filter cloths 16 (i.e. in the direction indicated by the arrow B in Fig. 26) by providing a resilient member such as a coil spring or the like (not shown) between the brackets b supported by the filter plate 5 or between the brackets b and the support frames 19, or further, by replacing the contact members with compression springs (not shown) between the stoppers f.

Furthermore, the scrapers 23J described as provided below the support rollers 23Jr in the foregoing arrangement may be modified to be provided above the support rollers 23Jr on the contrary, with the stoppers f and the contact members j being disposed below the support rollers 23Jr.

Since constructions and effects of the modified filter presses FG to FJ of Figs. 23 to 27 are generally similar to those of the filter press FA of Figs. 1 to 5 or other modifications described so far, detailed description thereof is abbreviated for brevity, with like parts being designated by like reference numerals.

Although the present invention has been fully described by way of example with reference to the accompanying drawings, it is to be noted here that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present invention, they should be construed as included therein.

Claims (9)

1. A filter press for separating raw liquid into a filtrate and filter residue, which comprises a plurality of filter plates each having a pair of spaced support frames at the lower portion thereof and movably mounted between support stands for selective spacing therebetween or clamping together to each other, a pair of filter cloths disposed between each set of the neighboring filter plates, a winding up means arranged to be driven for a forward or reverse rotation, cord members directed around said winding up means and respectively connected to upper edges of said filter cloths for selective lowering of said filter cloths into between the respective neighboring filter plates or lifting said filter cloths therefrom, and a filter cloth take-up roller journalled between the spaced support frames of each of said filter plates and engaged with the lower edges of said filter cloths which are to be wound thereonto and hold each of said filter plates therebetween, said filter cloth take-up roller being provided therein with a torsion spring arranged to urge said filter cloth take-up roller in a direction to wind up said filter cloths thereonto, the improvement comprising a pair of filter residue separating members each having a slit passage for passing the filter cloths therethrough so as to separate the filter residue adhering to said filter cloths and provided between said spaced support frames of each of said filter plates.

2. A filter press as claimed in Claim 1, wherein each of said filter residue separating members is composed of a pair of plate-like members to define therebetween, the slit passage having a slit width approximately equal to a thickness of said filter cloth and extending over a length at least equal to a width of said filter cloth for inwardly changing a travelling path of said filter cloth, one of said plate-like members to be held in sliding contact with the surface of said filter cloth being formed, at its upper edge, with a wedge-like edge portion.

3. A filter press as claimed in Claim 1, wherein each of said filter residue separating members is composed of confronting members which define the slit passage therebetween, and provided in pair at predetermined positions with respect to said filter cloth take-up roller supported between the spaced support frames for each of the filter plates, with a spring member expansible and contractible in a direction back and forth with respect to the filter plate being disposed between said filter residue separating members in pair, whereby upon spacing of said filter plates, said slit passage is positioned along the downward travelling path of said filter cloth generally in a vertical direction, and upon clamping together to each other of said filter plates, said slit passage is accommodated within a thickness of said filter plate through contraction of said spring member.

4. A filter press as claimed in Claim 1, wherein said filter residue separating members are pivotally supported by a support roller provided at a predetermined position with respect to the filter cloth take-up roller supported between the spaced support frames for each of the filter plates, whereby upon spacing of said filter plates, said filter residue separating members are pivoted by the filter cloths stretched by the urging force of the filter cloth take-up roller so as to position said slit passages along the downward travelling path of the filter cloth generally in a vertical direction, and upon clamping together to each other of said filter plates, said filter residue separating members are again pivoted so as to be accommodated.within the thickness of said filter plates.

5. A filter press for separating raw liquid into a filtrate and filter residue, which comprises a plurality of filter plates each having a pair of spaced support frames at the lower portion thereof and movably mounted between support stands for selective spacing therebetween or clamping together to each other, a pair of filter cloths disposed between each set of the neighboring filter plates, a winding up means arranged to be driven for a forward or reverse rotation, cord members directed around said winding up means and respectively connected to upper edges of said filter cloths for selective lowering of said filter cloths into between the respective neighboring filter plates or lifting said filter cloths therefrom, and a filter cloth take-up roller journalled between the spaced support frames of each of said filter plates and engaged with the lower edges of said filter cloths which are to be wound thereonto and hold each of said filter plates therebetween, said filter cloth take-up roller being provided therein with a torsion spring arranged to urge said filter cloth take-up roller in a direction to wind up said filter cloths thereonto, and means for separating filter residue from the filter cloths so arranged as to positively separate the filter residue therefrom without any damage to said filter cloths.

6. A filter press as claimed in Claim 5, wherein said filter residue separating means includes a set of guide rollers provided between said spaced support frames in positions above said filter cloth take-up roller, said guide rollers being eccentrically arranged, in respective axes thereof, both in a widthwise and vertical directions of said filter plate and disposed in positions close to each other in the vertical direction for passing the pair of filter cloths between said guide rollers so that travelling path of the respective filter cloths is bent by said guide rollers, whereby said travelling path of the filter cloths is altered by said guide rollers during downward travelling of said filter cloths so as to separate the filter residue from the filter cloths in such a manner as to draw said filter cloths through said guide rollers.

7. A filter press as claimed in Claim 5, wherein said filter residue separating means includes a pair of filter residue separating members which are arranged to contact the surfaces of the respective filter cloths so as to bend the travelling path of said filter cloths inwardly to a certain extent and which are supported between said spaced support frames in positions between said filter cloth takeup roller and a pair of filter cloth guide rollers journalled between said spaced support frames for bending the travelling path of said filter cloths holding the filter plate therebetween in directions closed to each other, whereby during downward travelling of said filter cloths, said travelling path of said filter cloths is altered inwardly between said filter cloth guide rollers and said filter cloth take-up roller so as to form small clearances between the filter residue adhering to the filter cloths and said filter cloths for separating the filter residue by directing said filter residue separating members into said small clearances.

8. A filter press as claimed in Claim 5, wherein said filter residue separating means includes scraper members each having a filter residue separating edge contacting one surface of each of the filter cloths, and pivotally supported on a shaft provided at the side of the other surface of the filter cloth in a position above the filter cloth takeup roller between said spaced support frames so as to normally keep said filter residue separating edge in contact with said one surface of the filter cloth for separation of the filter residue therefrom, and restricting members for restricting pivotal movement of said scraper members in directions to space the filter residue separating edges thereof from the filter cloths, whereby upon spacing of said filter plates, said scraper members are pivoted by the filter cloths stretched by the urging force of the torsion spring of said filter cloth takeup roller so as to align said filter residue separating edges of said scraper members with the downward travelling path of the filter cloths generally in the vertical direction, and upon clamping together of said filter plates to each other, said scraper members are pivoted so as to be brought into within thickness of each of said filter cloths.

9. A filter press substantially as herein described with reference to and as shown in the accompanying drawings.