GB2129699A

GB2129699A - Filter press

Info

Publication number: GB2129699A
Application number: GB08324074A
Authority: GB
Inventors: Tetsuya Kurita; Masayuki Nakamura; Haruo Hamazaki
Original assignee: Kurita Machinery Manufacturing Co Ltd
Current assignee: Kurita Machinery Manufacturing Co Ltd
Priority date: 1982-09-09
Filing date: 1983-09-08
Publication date: 1984-05-23
Also published as: DE3332632A1; GB8324074D0; DE3332632C2; SE8304798D0; SE454053B; MY100093A; GB2129699B; SE8304798L

Abstract

A filter press includes a series of filter plates 2, each of which has a slurry hole 2a, and a pair of filter cloths 4 interposed between each pair of plates. Each cloth has a through hole aligned with holes 2a, and the marginal portion of cloth adjacent the hole is clamped between two plates 6,7 by bolts 8. The bolts belonging to adjacent cloths 4 abut when the press is closed, providing a gap 9 by which slurry is fed from aligned holes 2a into the spaces 14 between the cloths. When the press is opened the cloths can be separated and washed, e.g. while being wound on to rollers. In the press shown, alternate plates 2' carry inflatable membranes 13. <IMAGE>

Description

SPECIFICATION Slurry feeding device for use in filter press The present invention generally relates to a filter cloth travelling type filter press including a plurality of filter plates each formed with a slurry hole and a plurality offilter cloths interposed in pairs between adjacent ones of the filter plates, in which the filter cloths are caused to travel upwardly and downwardly with respect to the filter plates and more particularly, to a slurryfeeding device for use in the filter cloth travelling type filter press, by which slurry to be filtered is fed from either one of the slurry holes of a pair of the adjacent filter plates into a filter chamber formed between a pair of the filter cloths, with the filter plates being clamped to each other.

Conventionally, in filter presses ofthe above described type, it has been so arranged that filter cloths are interposed in pairs between adjacent filter plates and a slurry feeding plate is disposed between each pair of the filter cloths. The slurry feeding plate of one-piece construction is formed with a through-hole communicated with a slurry feed opening of each filter cloth and is, further, formed therein with a feed passage extending downwardly from the throughhole and having an open lower end.Thus, it has been so arranged that, after the adjacent filter plates are clamped to each other so as to secure the slurry feeding plate between each pair ofthe adjacent filter plates, slurry to be filtered is fed from either one ofthe slurry holes of a pair of the adjacent filter plates into thefilterchamberformed by a pairofthefiltercloths therebetween through corresponding either one of the slurry feed openings of each pair of the filter cloths, the through-hole of the slurryfeeding plate and the feed passage of the slurry feeding plate.

However, the priorartslurryfeeding plate has such an inconvenience that, since it is structurally difficult to wash the slurry feeding plate, especially the feed passage, slurry remains in the through-hole and the feed passage even afterwashing thereof, thereby resulting in clogging ofthefeed passage. Furth ermore,theknownslurryfeeding plate has such a disadvantage that, since the slurryfeeding plate is of one-piece construction, it is difficultto repairthe clogged feed passage.Moreover, the known slurry feeding plate has been disadvantageous in that, since the slurryfeeding plate is of one-piece construction, the filter cloths attached to opposite sides of thee slurryfeeding plate are likely to be wrinkled, while assembly and replacementofthe slurryfeeding plate become extremely troublesome.

Preferred embodiments ofthe present invention provide an improvide slurry feeding device for use in a filter press, by which slurry to be filtered can be smoothly fed into afilterchamberformed between each pairoffiltercloths.

Another important object which may be attained is to provide an improved slurryfeeding device of the above described type which can be easily repaired and washed.

Still another object which may be attained isto provide an improved slurryfeeding device ofthe above described type which is simple in structure, highly reliable in actual use, suitable for mass production at low cost, and can be readily incorporated into filter presses and the like at low cost.

In accomplishing these and other objects according to one preferred embodiment ofthe present invention, there is provided an improved slurryfeeding device for use in a filter press including at least one pair offirst and second filter plates formed with first and second slurry holes, respectivelyandapairoffirst and second filter cloths imterposed between said first and second filter plates, with said first and second slurry holes confronting each other, said first and second filter cloths being, respectively, formed with first and second slurry feed openings and defining a filterchambertherebetween when said first and second filter plates are clamped to each other, said slurry feeding device being arranged to feed from either one of said first and second slurry holes into saidfilterchamber,slurryto befilteredandcomprising: a pair of first and second plate members which are, respectively, formed with first and second through-holes and are disposed between said first and second filter cloths; and a plurality of first and second fastening members by which said first and second filter cloths are, respectively, secured to said first and second plate members such that said first and second slurryfeed openings are, respectively, communicated with said first and second through-holes, with said first and second filter cloths being, respectively, interposed between said first filter plate and said first plate member and between said second filter plate and said second plate member; said first and second through-holes, when said first and second filter plates are clamped to each other, confronting each other so as to be, respectively, communicated with said first and second slurry holes through said first and second slurry feed openings such that said first and second through-holes are brought into communication with said filter chamber, wherebythe slurry is fed from either one of said first and second slurry holes into said filter chamberth rough corresponding either one of said first and second slurryfeed openings and corresponding either one of said first and second through-holes.

In embodiments of the present invention, when the first and second filter plates are retracted away from each otheraftera pressing step ofthefilter press, the first and second plate members can be separated awayfrom each other, so that slurry remaining between the first and second plate members can easily be washed away and thus, clogging of the clearance between the first and second plate members can be positively prevented, whereby slurryto be filtered can be fed into the filter chamber smoothly.

Some embodiments of the invention will now be described with reference to the accompanying drawings. in which: Fig. lisa fragmentary front elevational view offilter plates of a filter press provided with a slurryfeeding device according to a first embodiment of the present invention, Fig. 2 is a fragmentary longitudinal sectional view of the filter plates of Fig. 1 having the slurry feeding device of Fig. 1 interposed therebetween, Fig.3 is a front elevational view of the slurryfeeding device of Fig.1, with a filter cloth ofthefilter press being omitted for the sake of clarity, Fig. 4 is a longitudinal sectional view ofthe slurry feeding device of Fig. 1, which is attached to the filter cloth, Figs.Sand 6 are views similarto one portion of Fig.

2, particularly showing first and second modifications thereof, respectively, Fig. 7 is a view similarto Fig. 3, particularly showing a third modification thereof, Fig. 8 is a longitudinal sectional view of a slurry feeding device of Fig. 7, Fig. 9 is a viewsimilarto Fig. 8, particularly showing a fourth modification of the slurryfeeding device of Fig.1, Fig. is a front elevational view of either one of a pair of washer plates and corresponding either one of a pair of retainer plates employed in a slurry feeding device according to a second embodimentofthe present invention, Fig. 11 is a front elevational view of the other one of the pair of washer plates and the other one ofthe pair ofthe retainer plates ofthe slurryfeeding device of Fig.10, Fig. is a longitudinal sectional view of the slurry feeding device of Figs. 10 and 11, Fig. 13 is a viewsimilarto Fig. 2, particularly showing the filter plates having the slurryfeeding device of Fig. 12 interposed therebetween, Fig. 14and 15 are views similarto Figs. 10 and 11, respectively, particularly showing a first modification thereof, Fig. 16 is a longitudinal sectional view of a slurry feeding device of Figs. 14 and 15, Figs. 17 and 18 are views similarto Figs. 10 and 11, respectively, particularly showing a second modification thereof, Fig. 19 is a longitudinal sectional view of a slurry feeding device of Figs. 17 and 18, Fig. 20 is a view similarto Fig. 2, particularly showing the filter plates havingtheslurryfeeding device of Fig. 19 interposed therebetween, Fig. 21 is a fragmentary sectional view of a slurry feeding device according to a third embodiment ofthe present invention, Fig. 22 is a longitudinal sectional view of a slurry feeding device according to a fourth embodiment of the present invention, Fig. 23 is a front elevational view of either one of opposite slurryfeeding plates employed in a slurry feeding device according to a fifth embodiment ofthe present invention, Fig. 24 is a front elevational view of the other one of the opposite slurry feeding plates ofthe slurry feeding device of Fig.23, Fig. 25 is a longitudinal sectional view of the slurry feeding device of Figs. 23 and 24, Fig. 26 is a view similar to Fig. 2, particularly showing the filter plates having the slurry feeding device of Fig. 25 interposed therebetween, Fig. 27 is a viewsimilarto Fig. 24, particularly showing afirstmodificationthereof, Fig. 28 is a sectional view explanatory of attachment ofthe slurryfeeding plate of Fig. 27 to the filter cloth, Fig. 29 is a viewsimilarto Fig. 23, particularly showing a first modification thereof, Fig. 30 is a sectional view explanatory of attachment ofthe slurry feeding plate of Fig. 29 to the filter cloth, Fig. 31 is a view similarto Fig. 2, particularly showing the filter plates having a slurryfeeding device of Figs. 27 and 29 interposed therebetween, Figs. 32 and 33 are views similarto Figs. 27 and 28, respectively, particularly showing a second modification oftheslurryfeeding plate of Figs.24, Figs. 34 and 35 are views similarto Figs. 29 and 30, respectively, particularly showing a second modification of the slurry feeding plate of Fig. 23, and Fig. 36 is a view similarto Fig. 2, particularly showing the filter plates having a slurry feeding device of Figs. 32 and 34 interposed therebetween.

Before the description of the present invention proceeds, it isto be noted that like parts are designated by like reference numeralsthroughout several views of the accompanying drawings.

Referring nowto the drawings, there is shown in Figs. 1 and 2, a filter press in which a slurryfeeding device K1 according to a first embodiment ofthe present invention is incorporated. The filter press includes a plurality of ordinary filter plates 2 and pressing filter plates 2' arranged alternately and a plurality of filter cloths 4 interposed in pairs between adjacent ones ofthe ordinaryfilter plates 2 and the pressing filter plates 2'. It is so arranged that, atthe time of retraction of the adjacent ones ofthe ordinary filter plates 2 and the pressing filter plates 2' away from each other, each pair ofthefilter cloths 4 interposed between one of the ordinaryfilter plates 2 and an adjacent one ofthe pressing filter plates 2' and supported, attheir upper end, by a support rod (not shown) are caused to travel upwardly and downwardlywith respect to the ordinary filter plates 2 and the pressing filter plates 2' and that, atthe time of a pressing step of the filter press, slurryto be filtered is fed into between each pair ofthe filter cloths 4from either one of a slurry hole 2a of the ordinaryfilter plate 2 and a slurry hole 2'a ofthe pressing filter plate 2' through the slurryfeeding device K1 with the ordinary filter plates 2 and the pressing filter plates 2' being clamped to each other.As shown in Figs.3 and 4, the slurryfeeding device K1 generally includes a pair of annular washer plates 6, a pair of retainer plates 7 and a plurality of bolts 8 such that each ofthe filter cloths 4 is secured between each of the washer plates 6 and each of the retainer plates 7 by the use of the bolts 8.

The washer plate 6 has a circularthrough-hole 6a formed at a central portion thereof in communication with a circular slurry feed opening 4a ofthefiltercloth 4 and includes a plurality of bolt holes 6b formed at a pheripheral circumference ofthethrough-hole 6a.

Meanwhile, the retainer plate 7 is an elongated plate member having a semicircular upper portion. The retainer plate 7 has a circularthrough-opening 7a formed, atthe upper portion, in communication with theslurryfeed opening 4a ofthefiltercloth 4and includes a pluralityofthreaded holes 7b formed at a peripheral circumference ofthethrough-opening 7a in aligmentwith the bolt holes 6b. The washer plate 6 is brought into contactwith each of opposite faces of a pair ofthe filter cloths 4 interposed between the adjacent ordinaryfilter plate 2 and pressing filter plate 2' so as to enclose the slurry feed opening 4a.Then, the filter cloth 4 is interposed between the washer plate 6 and the retainer plate 7 and the bolts 8 are srewed into the threaded holes 7b ofthe retainer plate 7 from the side of the washer plate 6, so that the washer plate 6 and the retainer plate 7 are secured to thefiltercioth 4and, at the same time, head portions 8a ofthe bolts 8 projecting out of opposite faces of a pair of the washer plates 6 are brought into contact with each other when the ordinaryfilter plate 2 and the pressing filter plate 2' are clamped to each other, whereby a clearance 9 of a predetermined dimension is defined between the pair of the washer plates 6.

Furthermore, a cover plate 10 is secured, through the filter cloth 4, to a lower portion of the retainer plate 7 by bolts 11 so as to preventthefilter cloth 4 from slackening. It is so arranged that head portions 11 a of the bolts 11 secured to a pair of the cover plates 10 confront each other so as to be brought into contact with each other, so thatthe clearance 9 defined through contact of the opposite head portions 8a of the bolts 8 with each other is enlarged through contact ofthe head portions 1 la ofthe bolts 11 with each other, whereby slurry to be filtered can be smoothly fed into between the adjacent ordinary filter plate 2 and pressing filter plate 2'. Furthermore, an auxiliary filter cloth 12 is provided between the washer plate 6 and the filter cloth 4 so as to reinforce the filter cloth 4.

Meanwhile, it can be so arranged that, for example, the cover plate 10 has projections extending outwardly beyond the head portion 1 lea of the bolt 11 in a widthwise direction of the cover plate 10 such that the projections formed on a pair of the cover plates 10 are brought into contact with each other. Moreover, washers can be employed in place of the cover plate 10.

The slurryfeeding device K1 arranged as described above functions as follows. As shown in a right-hand portion of Fig. 2, in the case where the adjacent ordinary filter plate 2 and pressing filter plate 2' are clamped to each other, each ofthe retainer plates 7 is pressed against each of packing members 13 defining each oftheslurryhole2a oftheordinaryfilterplate2 and the slurry hole 2'a of the pressing filter plate 2' so as to be brought into close contacttherewith, so that the clearance 9 is defined between the pair ofthe washer plates 6 through contact of the opposite head portions 8a ofthe bolts 8 with each other and through contact of the opposite head portions 11 a of the bolts 11 with each other.Thereafter, slurryto be filtered is fed from either one ofthe slurry hole 2a ofthe ordinary filter plate 2 and the slurry hole 2'a ofthe pressing filter plate2' into corresponding either one ofthe throughholes 6a ofthewasher plates 6through corresponding either one of the through-openings 7a ofthe retainer plates 7 and corresponding either one ofthe slurry feed openings 4a of the filter cloths 4 such that a portion of the slurry is fed, for filtration, from the clearance 9 formed between the pair of the washer plates 6 into a filter chamber 14 formed between the pair of the filter cloths 4, with the remaining portion of the slurry being fed from the clearance 9 into the other one ofthe slurry hole 2a ofthe ordinary filter plate 2 and the slurry hole 2'a ofthe pressing filter plate 2' through the other one ofthethrough-holes 6a ofthe washer plates 6, the other one ofthe slurryfeed openings 4a ofthe filter cloths 4 and the other one of thethrough-openings7aofthe retainer plates 7.

On the othe hand, as shown in a left-hand portion of Fig. 2, in the case where the adjacent ordinary filter plate 2 and pressing filter plate 2' are retracted away from each other, the support rod forthe filter cloth 4 is caused to move downwardly and, at the same time, the pair of the filter cloths 4 are wound for washing thereof, For example, in the case where the pairofthe filter cloths 4 are wound downwardly of the ordinary filter plate 2 and the pressing filter plate 2' by separate winding rollers in opposite directions, a clearance between the pair ofthefilter cloths 4 is increased, so thatthe pair of the washer plates 6 pressed against each otherthrough the head portions 8a ofthe bolts 8 and the head portions 11 a of the bolts 11 are separated away from each other and thus, the opposite faces of the pair of the washer plates 6 can be washed easily and positively, whereby such an undesirable phenomenon can be positively prevented that slurry remains in the clearance 9 between the pair of the washer plates 6 with the resultthatthe clearance 9 is clogged bythe slurry. Furthermore, since the bolts 8 and 11 are provided symmetrically with respect to a longitudinal central axis of the retainer plate 7, a uniform force is applied to the slurry feeding device K1 without being subjected to an overload.

Meanwhile, although the ordinary filter plate 2 and the pressing filter plate 2' have the slurry holes 2a and 2'a, respectively, disposed outwardly offiltration areas thereof in the above described embodiment, it can be so modified that the ordinary filter plate 2 and the pressing filter plate 2' have the slurry holes 2a and 2'a disposed inside the filtration areas, respectively.

Referring nowto Fig. 5, there is shown a slurry feeding device K1 (1) which is a first modification of the slurryfeeding device K1. In the first modified slurry feeding device K1 (1), a fastening screw 15 having, at one end thereof, a small diameter rod portion 15a and, atthe other end thereof, a threaded portion 1 5b is employed in place of the bolt 8. The rod portion 15a is tightlyfitted into a hole 7c ofthe retainer plate so as to be welded, at its end, to the retainer plate 7 such that the threaded portion 15b projecting outofthewasher plate 6through the filter plate 4 is provided with a nut 16.The nuts 16 fastened to the opposite fastening screws 15 are brought into contact with each other such thatthe clearance 9 is defined between the pair of the washer plates 6.

Referring to Fig. 6, there is shown a slurry feeding device K1 (2) which is a second modification of the slurry feeding device K1. In the second modified slurry feeding device K1 (2), a stud bolt 17 having, at one end thereof, a threaded portion 1 7a and, at the other end thereof, a threaded portion 17b is employed in place of the bolt 8. Thethreaded portion 17a is screwed into the threaded hole 7b of the retainer plate 7 and the threaded portion 17b is fastened by the nut 16through the filter cloth 4 and the washer plate 6. The nuts 16 fastened to the opposite stud bolts 17 are brought into contact with each other such thatthe clearance 9 is defined between the pair of the washer plates 6.

Referring to Figs. 7 and 8, there is shown a slurry feeding device K1 (3) which is a third modification of the slurryfeeding device K1. In the third modified slurryfeeding device K1 (3), a plate 18 provided with a through-hole 18a and formed slightly smaller, in shape, than the retainer plate 7 is employed in place of the washer plate 6 and the cover plate 10 and thus, the number of the components ofthe slurry feeding device has been reduced.As shown in Fig. 9, the third modified slurry feeding device K1 (3) can be further modified to a fourth modified slurryfeeding device K1 (4) in which a countersunk screw 19 and the nut 16 are employed in place of the bolt 8 and thus, the nuts 16 fastened to the opposite countersunkscrews 19 are brought into contact with each other such that the clearance 9 is defined between the pair of the plates 18.

Meanwhile, when the through-hole 6a of the washer plate 6 and the through-opening 7a ofthe retainer plate 7 are formed smaller, in shape, than the slurry feed opening 4a ofthe filtercloth 4, a periphery of the slurryfeed opening 4a ofthe filter cloth 4 can be protected and flow control of the slurry can be performed.

Furthermore, it can be so arranged that the throughholes 6a of the washer plates 6 and the throughopenings 7a ofthe retainer plates 7 are formed gradually smaller in a direction remote from a feeding end of slurry to be filtered so as to gradually restrict flow of the slurry.

Moreover, the washer plate 6 is not required to be of one-piece construction and therefore, can be divided in a circumferential direction thereof. Thus, the washer plate 6 can be replaced by a plurality of washers.

In addition,thewasher plate 6 is not restricted, in shape, to a circular shape and may have any arbitrary shape such as ellipse, etc. for securing the filter cloth 4.

Likewise,the retainer plate 7 may be of any arbitrary shape for securing the filter cloth 4.

Referring now to Figs. 10 to 13, there is shown a slurryfeeding device K2 according to a second embodiment of the present invention. In the slurry feeding device K2, the bolts 8 secu red to one of the pair of the plates 18 are provided out of alignment with the bolts 8 secured to the other one of the pair ofthe plates 1 8 such that the head portions8a of the bolts8 secured to the one ofthe pair of the plates 18 and the head portions 8a of the bolts 8 secured to the other one of the pair of the plates 18 are, respectively, brought into contact with the other one and the one ofthe pair of plates 18 when the ordinary filter plate 2 and the pressing filter plate 2' are clamped to each other, whereby the clearance 9 is defined between the pair of the plates 18.

Referring to Figs. 14two 16, there is shown a slurry feeding device K2 (1) which is a first modification of the slurry feeding device K2. In the first modified slurry feeding device K2 (1), the bolts 8 disposed atthe periphery of thethrough-hole 1 8a of the plate 18 are replaced by bolts 5 each having a head portion 5a and washers 20. Furthermore, in the first modified slurry feeding device K2 (1), the bolts 8 secured to a lower portion ofthe plate 18 are replaced by bolts 21 each having a head portion 21 a.Since the bolts 5 secured to one ofthe pair of the plates 18 are provided out of alignment with the bolts 5 secured to the other one of the pairofthe plates 18,the head portions 5a ofthe bolts 5 secured to the one ofthe pair ofthe plates 18 and the head portions 5a ofthe bolts 5 secured to the other one of the pair of the plates 18 are, respectively, brought into contact with the other one and the one of the pair of the plates 18 when the ordinaryfilter plate 2 and the pressing filter plate 2' are clamped to each other, wherebythe clearance 9 is defined between the pair of the plates 18.Meanwhile, since the bolts 21 secured to the one ofthe pairofthe plates 18 are provided in alignment with the bolts 21 secured to the other one of the pair of the plates 18, the head portions 21 a of the bolts 21 secured to the one ofthe pair of the plates 18 and the head portions 21 a ofthe bolts 21 secured to the other one ofthe pair of the plates 18 are brought into contact with each other when the ordinary filter plate 2 and the pressing filter plate 2' are clamped to each other, wherebytheclearance 9 defined through contact of the opposite head portions 5a of the bolts 5 with each other is further expanded to the lower portion of the plate 18.Furthermore, since the bolts 5 are provided with the washers 20, the clearance 9 defined between the pair ofthe plates 18 can be changed or can be maintained at a predetermined value even in the case where such undesirable phenomena as variations ofthickness of the filter cloth 4, machining errors of the plates 18, etc. take place, by changing the number ofthewashers20 or changing thethicknessofthewashers 20.

Referring to Figs. 17 to 20, there is shown a slurry feeding device K2 (2) which is a second modification of the slurryfeeding device K2. In the second modified slurry feeding device K2 (2),thefirst modified slurry feeding device K2 (1) is so modified that the plate 18 is replaced bytheannularwasherplate 6and the cover plate 10.Accordingly, in the second modified slurry feeding device K2 (2), the bolts 5 secured to one of the air ofthe washer plates 6 are brought out of alignment with the bolts 5 secured to the other one ofthe pair of the washer plates 6, sothatthe head portions 5a of the bolts 5 secured to the one of the pair of the washer plates 6 and the head portions 5a ofthe bolts 5 secured to the other one of the pair of the washer plates 6 are, respectively, brought into contact with the other one and the one of the pair ofthe washer plates 6 when the ordinary filter plate 2 and the pressing filter plate 2' are clamped to each other, wherebythe clearance 9 is defined between the pair of the washer plates 6.

Meanwhile, since the bolts 11 secured to one ofthe pair the cover plates 10 are provided in alignment with the bolts 11 secured to the other one ofthe pair of the cover plates 10, the head portions 11 a of the bolts 11 secured to the one of the pair of the cover plates 1 0 and the head portions 11 a ofthe bolts 11 secured to the other one ofthe pair ofthe cover plates 10 are brought into contactwith each otherwhenthe ordinary filter plate 2 and the pressing filter plate 2' are clamped to each other. Since the plate 18 is replaced by the washer plate 6 and the cover plate 10 in the second modified slurry feeding device K2 (2), the second modified slurry feeding device K2 (2) is reduced, in weight, than the slu rry feeding device K2 and the first modified slurryfeeding device K2 (1), whereby a load applied to the filter cloth 4 can be reduced.

Since other constructions of the slurry feeding devices K2, K2 (1) and K2 (2) are similarto those of the slurry feeding devices K1 and K1 (1)toK1 (4), detailed description thereof is abbreviated forthe sake of brevity.

Referring nowto Fig.21, there is shown a slurry feeding device K3 according to a third embodiment of the present invention. In the slurryfeeding device K3, the fourth modified slurry feeding device K1 (4) (Fig. 9) is further so modified that the plate 18 and the retainer plate 7 are replaced by the ring 25. More specifically, the slurry feeding device K3 generally includes a pair of rings 25, a plurality of flush bolts 26 and a plurality ofthe nuts 16. The ring 25 has a circular through-hole 25a formed at a central portion thereof and includes a plurality of countersunk holes 25b formed ata peripheral circumference of the through-hole 25a.The pair of the rings 25 are disposed between the pair of the filter cloths 4 which are interposed between the ordinary filter plate 2 and the pressing filter plate 2' such thatthe countersunk holes 25b ofthe pair of the rings 25 confrontthe corresponding filter cloths 4.

Then, the flush bolts 26 are inserted into the countersunk holes 25b of each of the pair ofthe rings 25 through each of the pairofthefiltercloths4so asto project out of each ofthe pair of the rings 25 into the clearance 9 such that each ofthethrough-holes 25a of the rings 25 is brought into communication with each of the slurry feed openings 4a of the filter cloths 4, with the filter cloths 4 being caused to slightly sink into the countersunk holes 25b. Consequently, when the rings 25 are attached to thefilter cloths 4, mounting portions of the filter cloths 4, adjacent to the countersunk holes 25b are desirably prevented from slackening. Subsequently, the nuts 16 are attached to the projecting portions of the flush bolts 26 between the pair of the rings 25.Since the flush bolts 26 secured to one ofthe pair of the rings 25 are provided in alignmentwith the flush bolts 26 secured to the other one ofthe pair ofthe rings 25, the nuts 16 oftheflush bolts 26 secured to the one ofthe pairofthe rings 25 and the nuts 16 oftheflush bolts 26 secured to the other one of the pair of the rings 25 are brought into contactwith each otherwhentheordinaryfilterplate2 and the pressing filter plate 2' are clamped to each other, wherebythe clearance 9 is defined between the pair of the rings 25. Since other constructions of the slurryfeeding device K3 are similarto those of the slurry feeding device K1, detailed description thereof is abbreviated forthe sake of brevity.

Referring nowto Fig .22, there is shown a slurry feeding device K4 according to a fourth embodiment ofthe present invention. The slurryfeeding device K4 generally includes circular washer plates 30 and 31 and a plurality of countersunk screws 32. The washer plates 30 and 31 havethrough-holes 30a and 31 a formed at central portions thereof, respectively. The washer plate 30 has a plurality of projections 30b formed at a peripheral circumference of the through hole 30a such that th e projections 30b confrontthe washer plate 31. The washer plate 30 further has a plurality ofcountersunkthreaded holes 30c formed at the projections 30b and from one face thereof adjacent to the corresponding filter cloth 4.Meanwhile, the washer plate 31 has a plurality of countersunk threaded holes 31 bformed at corresponding posi tions ofthe countersunkthreaded holes30cofthe washer plate 30 and from one face thereof adjacent to the corresponding filter cloth 4.Thus, the pair ofthe filter cloths 4 interposed between the ordinaryfilter plate 2 and the pressing filter plate 2' are attached to the washer plates 30 and 31 by screwing the countersunkscrews 32 into the countersunkthreaded holes 30c and 31 b, respectively, such that the slurryfeed openings 4a ofthe pair ofthefilter cloths 4 are brought into communication with the through-hole 30a of the washer plate 30 and thethrough-hole 31a of the washer plate 31, respectively, with the filter cloths 4 being caused to slightly sink into the countersunk threaded holes 30c and 31 b, respectively.Accordingly, when the ordinaryfilter plate 2 and the pressing filter plate 2' are clamped to each other, the projections 30b ofthe washer plate 30 are brought into contactwith the washer plate 31 , whereby the clearance 9 is defined between the washer plates 30 and 31. It can be so modified that the washer plates 30 and 31 are divided in circumferential directions thereof. Furthermore, it can be so modified that a plurality of first and second projections provided out of alignment with each other are, respectively, formed on the washer plates 30 and 31 such that the first and second projections are, respectively, brought into contact with the washer plates 31 and 30 when the ordinary filter plate 2 and the pressing filter plate 2' are clamped to each other, wherebythe clearance 9 is defined between the washer plates 30 and 31.

Moreover, it can be so modified thatthe projections 30b are provided separately from the washer plate 30 and is secured to the washer plate 30 by any suitable coupling means such as fusion, bonding, bolting, etc.

Since other constructions of the slurryfeeding device K4 are similarto those of the slurryfeeding device K1, detailed description thereof is abbreviated for the sake of brevity.

Referring nowto Figs. 23to Fig. 26, there is shown a slurryfeeding device K5 according to a fifth embodi mentofthe present invention. The slurryfeeding device K5 generally includes slurryfeeding plates 35 and 37 confronting each other and retainer plates 36 and 38 such thatthe retainer plates36 and 38 are, respectively, secured to the slurry feeding plates 35 and 37through the filter cloths 4.The slurryfeeding plate 35 of elliptic shape has an ellipticthrough-hole 35a formed in communication with the slurryfeed opening 4a ofthefilter cloth 4 and includes a plurality of bolt holes 36b formed at a periphery of the through-hole 35a, with each of the bolt holes 35b being formed with a spot facing portion35c.The retainer plate 36 is substantially similar, in shape, to the slurryfeeding plate 35 and has an elliptic through-opening 36a formed in communication with thethrough-hole 35a. The retainer plate 36 further has a plurality of screw rods 36' provided at corresponding positions of the bolt holes 35b ofthe slurry feeding plate 35. More specifically, the screw rods 36' each have, at one end thereof, a rod portion 36b welded to the retainer plate 36 and, atthe other end thereof, a threaded portion 36c projecting outofthe retainer plate 36. Accordingly, the threaded portions 36c of the screw rods36' are inserted, through the filter cloth 4, into the bolt holes 35b ofthe slurry feeding plate 35 so as to be fastened by The nuts 16 at the spot facing portions35c,wherebytheslurryfeeding plate 35 is secured to the filter cloth 4.

Meanwhile, the slurryfeeding plate 37 of circular shape has a circularthrough-hole 37a formed, at a central portion thereof, smallerthanthethrough-hole 35a ofthe slurryfeeding plate 35, with thethrough- hole 37a being brought into communication with the slurryfeed opening 4a ofthefiltercloth 4. The slurry feeding plate 37 further has a plurality of bolt holes 37b formed at a periphery of the through-hole 37a, with each of the bolt holes 37b being formed with a spotfacing portion 37c. The retainer plate 38 is substantially similar, in shape, to the slurry feeding plate 37 and has a circularthrough-opening 38a formed, at a central portion thereof, in communication with thethrough-hole37a.The retainer plate 38 further has a plurality of screw rods 38' provided at corresponding positions ofthe bolt holes 37b ofthe slurryfeeding plate 37. In the same manner as in the screw rods 36', the screw rods 38' each have, at one end thereof, a rod portion 38b welded to the retainer plate 38 and, at the other end thereof, a threaded portion 38c projecting out ofthe retainer plate 38.

Consequently, thethreaded portions 38e of the screw rods 38' are inserted, through the filter cloth 4, into the bolt holes 37b of the slurry feeding plate 37 so as to be fastened by the nuts 16 at the spot facing portions 37c, wherebythe slurry feeding plate 37 is secured to the filter cloth 4, with the slurryfeeding plates 35 and 37 confronting each other.

As best shown in Fig. 25, when the slurryfeeding plates 35 and 37 are secured to the pair ofthefilter cloths 4, respectively and then, the ordinary filter plate 2 and the pressing filter plate 2' are clamped to each other, thethrough-hole 35a of the slurry feeding plate 35 extends downwardly beyond a lower end ofthe slurryfeeding plate 37, so that a clearance having a width substantially equal to the thickness of the slurry feeding plate 37 is defined between a lower end portion ofthe slurry feeding plate 35 and the filter cloth 4secured to the slurryfeeding plate 37, whereby a lower end portion ofthethrough-hole3Sa is brought into communication, through the clearance 39, with the filter chamber 1 4 formed between the pair of the filter cloths 4.

Referring to Figs. 27 to 31, there is shown a slurry feeding device K5 (1) which is a first modification of the slurry feeding device KS. In the first modified slurry feeding device Us (1), the slurryfeeding plates 35 and 37 and the retainer plates 36 and 38 are replaced by slurryfeeding plates 42 and 40 and retainer plates 43 and 41, respectively.As shown in Figs. 27 and 28, the slurry feeding plate 40 and the retainer plate 41 have a pair of leg portions 40a and a pair of leg portions 41 a extending downwardly, respectively, whereby the filter cloth 4 can be reliably secured between the slurry feeding plate 40 and the retainer plate 41 and, atthe same time, the clearance 39 can be positively defined between the slurry feeding plate 42 and the filter cloth 4 secured to the slurry feeding plate 40. Meanwhile, the through-hole 35a of the slurryfeeding plate 42 has an inclined face 42a formed at a lower portion thereof such thatthe inclined face 42a extends obliquely and downwardly toward a lower portion oftheslurry feeding plate 40.Accordingly, as best shown in Fig. 31, slurryto be filtered can be remarkably smoothlyfed from the lower end portion ofthethrough-hole 35a of the slurryfeeding plate 42 into the filter chamber 14 through the clearance 39. Furthermore, the leg portions 40a functions to press a pressing membrane of the pressing filter plate 2' such that a sealing area between the pressing membrane and a core plate of the pressing filter plate 2' is enlarged.

Referring to Figs. 32 to 36, there is shown a slurry feeding device K5 (2) which is a second modification of the slurryfeeding device KS. In the second modified slurry feeding device K5 (2), the first modified slurry feeding device K5 (1) is further so modifiedthatthe retainer plates 41 and 43 are, respectively, replaced by retainer plates 45 and 46.The retainer plate 45 has a semicircular lower portion, so thatthefilter cloth 4 is supported bythe retainer plate 45 more positively and a portions ofthefiltercloth 4 disposed between the leg portions 40a is prevented from making pivotal movements, whereby the clearance 39 is stably defined between the slurryfeeding plate 42 and the filter cloth 4 secured to the slurryfeeding plate 40 when the ordinary filter plate 2 and the pressing filter plate 2' are clamped to each other.Meanwhile,the retainer plate 46 has a circularthrough-opening 46a such thatthe slurry hole 2a ofthe ordinaryfilter plate 2, the slurry hole 2'a ofthe pressing filter plate 2', the slurry feed openings 4a of the filter cloths 4, the through-hole 37a of the slurryfeeding plate 40,thethrough-opening 38a of the retainer plate 45 and thethrough-opening 46a of the retainer plate 46 have a circular shape of a substantially identical diameter. Since other constructions ofthe slurry feeding devices K5, K5 (1) and K5 (2) are similarto those ofthe slurryfeeding device K1, detailed description thereof is abbreviated forthe sake of brevity.

ltshould be noted herethattheslurryfeeding devices K1 to K5 ofthe present invention are not exclusively applied to the filter presses having the ordinaryfilter plates 2 and the pressing filter plates 2' arranged alternately but also can be applied to filter presses provided with onlythe pressing filter plates 2' orfilter presses provided with only the ordinary filter plates 2. Furthermore, in the above described embodiments, it can also be so arranged thatthe pair of the filter cloths are supported so asto straddlethefilter plate orthefilter press is of a type having a so-called panatagraph type suspension device mounted on the filter plate, from which the filter cloths are suspended.

In addition, it can be so arranged that a washing device forthefiltercloths is inserted from outside ofthefilter plates in between the filter plates or is disposed below the filter plates such that a washing pipe ofthe washing device is moved, forwashing, toward the filter cloths when the filter plates are retracted away from each other.

As is clearfrom the foregoing description, since each pair of washer plates are separated away from each other when the filter plates are retracted away from each other, such an undesirable phenomenon can be positively eliminated that slurry remains in the clearance between the pair ofthe washer plates with thereslutthattheclearanceisclogged bytheslurry, whereby slurry to be filtered can be smoothly fed into the filter chamber and the pair of the filter cloths can be separated away from each other by a large distance, resulting in easy repairorwashing ofthe slurry feeding device.

Furthermore, in preferred embodiments of the invention, the slurryfeeding device is of simple structure so that it can be assembled easily.

In preferred embodiments the washer plate and the retainer plate are secured to each other so as to interpose the filter cloth; therefore, the slurry hole of the filter plate, thethrough-opening ofthe retainer plate andthethrough-hole of the washer plate can be positively brought into communication with each other and the retainer plate can be reliably brought into close contact with the filter plate.

In addition, the conventional slurryfeeding plates each having the feed passage formed therein are large in thickness and therefore, are heavy in weight, thus subjecting the filter cloth to an overload. On the other hand, in embodiments of the present invention where the clearance is defined between the pair of the washer plates through contact of the projections ofthe opposite fastening members with each other, the washer plate and the retainer plate both attached to the filter cloth can be formed smaller, in thickness, than the conventional slurry feeding plates and thus, can be made lighter in weight, than the conventional slurryfeeding plates, so that an overload is not applied to the filter cloth.

Furthermore, in embodiments ofthe present invention, the feed passage is not subjected to directional restrictions, so slurry to be filtered can be fed from the through-hole ofthewasher plate into any arbitrary direction extending at right angles to the axis of the through-hole of the washer plate, so that a rate for feeding the slurry into thefilterchamber can be increased and thus, a production efficiency of the filter press can be improved.

Moreover,theconventionalslurryfeeding plate has the feed passage formed therein and therefore, is required to be machined accurately. On the contrary, in accordance with the present invention, the clearance may be defined between the pair of the washer plates through contact of the opposite fastening members with each other. Thus the cost of the slurry feeding device can be reduced.

In addition, since the washer plate and the retainer plate may be attached to each of the filter cloths, each ofthefilterclothscan be smoothly çmoved.

Meanwhile, in embodiments of the present invention, when the filter plates are clamped to each other, the projections formed on either one ofthe washer plates are brought into contact with the other one of the washer plates, whereby the clearance is positively defined between the washer plates.

Furthermore, in preferred embodiments ofthe invention, since the through-hole of one ofthe slurry feeding plates is formed so as to extend downwardly beyond the lower end of the other one ofthe slurry feeding plates when the filter plates are clamped to each other, the clearance is defined between the lower end portion ofthe one of the slurry feeding plates and the filter cloth attached to the other one of the slurry feeding plates, whereby slurry to be filtered can be fed from the through-hole of the one of the slurry feeding plates into the filter chamber through the clearance.

Although the present invention has been fully described by way of example with reference to the accompanying drawings, it isto be noted here that various changes and modifications will be apparent to those skilled in the art.

Claims

1. Aslurryfeeding device for use in a filter press including at least one pair of first and second filter plates formed with first and second slurry holes respectively and a pair of first and second filter cloths interposed between said first and second filter plates with saidfirstand second slurry holes confronting each other, said first and second filter cloths being, respectively, formed with first and second slurryfeed openings and defining a filter chambertherebetween when said first and second filter plates are clamped to each other, said slurry feeding device being arranged to feed from either one of said first and second slurry holes into said filter chamber, slurryto be filtered and comprising:: a pair of first and second plate members which are, respectively, formed with first and second throughholes and are disposed between said first and second filter cloths in use; and a plurality of first and second fastening members for securing said firstand second firstfilter cloths respectively, to said first and second plate members such that said first and second slurry feed openings are, respectively, communicated with said first and second through-holes, with said first and second filter cloths being, respectively, interposed between said first filter plate and said first plate member and between said second filter plate and said second plate member; the arrangement being such that in use said first and second through-holes, when said first and second filter plates are clamped to each other, confront each other so as to be, respectively, communicated with said first and second slurry holes through said first and second slurryfeed openings such that said first and second through-holes are brought into communication with said filter chamber, wherebythe slurry is feedable from either of said first and second slurry holes into said filter chamber through corresponding either one of said first and second slurry feed openings and corresponding either one of said first and second through-holes.

2. Aslurryfeeding device as claimed in Claim 1, wherein said first and second plate members are so arranged that when said first and second filter plates are clamped to each other, the members are spaced away from each other in an axial direction of said slurry holes so as to form a clearance between a first face of said first plate member remote from said first filter cloth and a second face of said second plate member remote from said filter cloth such that said first and second through-holes are brought into communication with said filter chamber, with said first face and said second face confronting each other.

3. Aslurryfeeding device as claimed in Claim 2, wherein said first and second fastening members includefirstand second projecting portionswhich project out of said first and second faces into said clearance, said first and second projecting portions, when said first and second filter plates are clamped to each other, being brought into contactwith each other so as to form said clearance between said firstface and said second face.

4. A slurryfeeding device as claimed in Claim 2, wherein said first and second fastening members includefirstandsecond projecting portions which project outofsaidfirst and second faces intosaid clearance, said first and second projecting portions, when said first and second filter plates are clamped to each other, being, respectively, brought into contactwith said second face and said first face so as to form said clearance between said firstface and said second face.

5. Aslurryfeeding device as claimed in Claim 2, wherein at least either one of said first and second plate members includes projecting portions formed on corresponding either one of said first and second faces, said projecting portions, when said first and second filter plates are clamped to each other, being brought into contact with the other one of said first and second faces so asto form said clearance between said first face and said second face.

6. Aslurryfeeding device as claimed in Claim 1, wherein said first and second plate members are brought into contact with each other when said first and second filter plates are clamped to each other, either one of said first and second plate members being formed largerthan the other one of said first and second plate members such that corresponding either one of said first and second through-holes extends, in communication with the other one of said first and secondthrough-holes, beyond a peripheral edge portion of the other one of said first and second plate members at right angles to an axial direction of said first and second slurry holes when said first and second filter plates are clamped to each other, whereby said first and second through-holes are brought into communication with said filter chamber.

7. Aslurryfeeding device as claimed in Claim 3 or 4,furtherincluding a pairoffirstand second retainer plates which are formed with first and second through-openings, and are in use respectively, secured to said first and second plate members through said first and second filter cloths bysaid first and second fastening members so as to be interposed between said firstfilter plate and said first filter cloth and between said second filter plate and said second filter cloth such that said first and second throughopenings are, respectively, communicated with said first and second through-holes through said first and second slurryfeed openings, said first and second through-openings, when said first and second filter plates are clamped to each other, being, respectively, communicated with said first slurry hole and said second slurry hole, whereby the slurry is fed from either one of said first and second slurry holes into said filter chamberthrough corresponding either one of said first and second throughopenings, corresponding either one of said first and second slurryfeed openings and corresponding either oneofsaidfirstand second through-holes.

8. Aslurryfeeding device as claimed in Claim 3,4 or7, wherein said first and second fastening members are bolts each formed with a head portion acting as each of said first and second projecting portions.

9. A slurry feeding device as claimed in Claim 3,4 or7, wherein said first and second fastening members ire bolts and nuts such that the nuts act as said first and second projecting portions.

10. Aslurryfeeding device as claimed in Claim 8 or 9further including washers by which said clearance between said firstface of said first plate member and said second face of said second plate member can be adjusted.

11. A slurry feeding device substantially as described and exemplified herein with reference to and as illustrated in any of the accompanying drawings.

12. Afilter press assembly comprising a slurry feeding device according to any preceding claim and at least one pair of said filter plates and at least one pair of said filter cloths.

13. Afilter press assembly substantially as described and exemplified herein with reference to and as illustrated in anyofthe accompanying drawings.