SG176384A1

SG176384A1 - Chamber filter element

Info

Publication number: SG176384A1
Application number: SG2011035409A
Authority: SG
Inventors: Juergen Lange Klaus; Paschedag Thomas; Scharnagl Reinhard
Original assignee: Andritz Tech & Asset Man Gmbh
Priority date: 2010-05-21
Filing date: 2011-05-18
Publication date: 2011-12-29
Also published as: CN102247721B; EP2388055B1; AT509341A4; PL2388055T3; CN102247721A; AT509341B1; EP2388055A1; MY171908A

Abstract

Chamber Filter ElementAbstractThe invention relates to a chamber filter element (1) for a filter press with several filter elements, where each two membrane filter elements (10) with a chamber filter element (1) in between are joined to one another with5 sealed edges and form filter chambers (12) between the chamber filter element (1) and the membrane filter element (10) into which an inlet opening (4) leads for the suspension fed in through the chamber filter element (1) and which is to be filtered. According to the invention it is characterised by an open inlet cross-section (8) from the inlet opening (2)10 to the filter chambers (12) arranged on either side being provided in the chamber filter element (1). In addition, the invention relates to a filter press with chamber filter elements (1) according to the invention. This can avoid blockages and increase the throughput of the filter press.15(Fig. 4)

Description

Chamber Filter Element

The invention relates to a chamber filter element for a filter press with several filter elements, where each two membrane filter elements with a chamber filter element in between are joined to cone another with sealed edges and form filter chambers between the chamber filter element and the membrane filter element into which an inlet opening leads for the suspension fed in through the chamber fitter element and which is to be filtered. The invention also relates to filter presses with chamber filter elements according to the invention. in filter presses of this kind, elastic membranes are used that are covered with a filter cloth, where the suspension to be filtered is pressed into the filter chamber and against the filter cloth. in the following, a “membrane” 16 is understood as being a flexible and impermeable surface element. The filtrate between filter cloth and membrane is then discharged and the filter cake remains in the filter chamber. in order to dewater the filter cake, overpressure is generally applied between the supporting plate and the membrane, causing the membrane to bulge into the filter chamber and thus press onio the filter cake. As a result, the residual moisture is removed from the filter cake.

One difficulty arises in the region of the inlet opening to the filter chamber, in principle, the inlet opening should be designed such as to be large enough to allow the filter chamber to be filled rapidly with the suspension to be filtered. This process leads, however, fo a risk of the membrane being overstretched in the area of the inlet opening during the pressing phase, and thus of considerable local material strain on the membrane. in addition, the filling channels are also filled with sludge during filling of the chambers. This also resulls in compacting of the sludge cake in the subsequent membrane presses in the sludge inlet area to the chamber, which then continues as far as the vertical feed area. A cake compacted in this way in this area is difficult or impossible fo remove. When the chambers are to be filled again in the next stage, they are filled more slowly, unevenly, or not at all, which creates a problem. In addition, this leads to uneven filling of the individual chambers due to compacting of the solids in the inlet gap to the filter chamber during subsequent pressing, where the inlets remain clogged in places during cake discharge. During re-filling, the chambers with the blocked inlets are not filled at all or not filled adequately, resulting in plates breaking due io the different pressures between the individual chambers.

The aim of the invention is to create a system in which cake compacting at the inlet area during membrane pressing is minimized in such a way that the suspension in the inlet area remains hydraulically mobile, i.e. it does not block the channel.

The invention is thus characterised by an open inlet cross-section from the inlet opening to the filter chambers arranged on either side being provided in the chamber filter element, where the chamber formed in the chamber filter element by the open inlet cross section can be closed off at one of its ends by a plate element that can be sianted on both sides. As the stationary sludge in the vertical feed area cannot rest on the “soul” of the filter plate during membrane compacting and the cake is only pressed together (from each side by one membrane on either side), the sludge remains hydraulic, Le. it can be pressed into the filter chamber when more sludge is fed in and thus does not block the feed. In order fo ensure, however, that this somewhat compacted, but still hydraulically mobile shidge can be discharged even more easily, it is advantageous fo provide additional slants (so-called draft angles) that direct the cake such that it slides out of the vertical channel and into the chamber.

in order to avoid the membrane being overstretched during the pressing phase in the area of the inlet opening, the invention provides for a cover plate being placed round the inlet opening. If the inlet opening is divided info more than one opening, for example two openings, even better support can be provided for the membrane. ft has proved an advantage if the cover plate is slanted. In this way, any sharp edges that could cause damage fo the membrane are avoided.

In addition, the invention relates to a filter press with chamber filter elements according to the invention.

The invention is now described by means of examples on the basis of the drawings, where,

Fig. 1 shows a state-of-the-art chamber fiiter element,

Fig. 2 shows a sectional view along the line marked 1I-}t in Fig. 1 through the state-of-the-art inlet opening,

Fig. 3 shows a chamber filter element according to the invention,

Fig. 4 shows a sectional view along the line marked IV-IV in Fig. 3, and

Fig. 5 shows a sectional view through the combination of membrane filter elements and chamber filter element.

Figure 1 illustrates a state-of-the-art chamber filter element 1, showing the feed opening 2 for the suspension to be dewatered. This chamber filler element 1 adjoins a membrane filter element (tem 10 in Fig. 5) in a filter press and serves largely fo feed the suspension into the filter chamber,

In Fig. 2, a sectional view H-ll through the inlet area of the chamber filter element 1 is then shown. The feed opening 2 opens inte inlet gaps 3 3C arranged on both sides, which open in turn into inlet openings 4 arranged on either side of the chamber filter element 1 and through which the suspension is guided into the filter chamber (tem 12 in Fig. 5) between the chamber filter element 1 and the membrane filter element {Item 10 in

Fig. 5). The inlet gaps 3 are bordered by the plate element 5 towards the middle of the chamber filter element 1. Ths inlet gaps 3 leading to the inlet openings 4 are very narrow and thus limit the flow of suspension into the filter chamber {item 12 in Fig. 5).

Figure 3 now shows a chamber filter element 1 according to the invention, with the feed opening 2. In addition, this figure shows that the inlet opening 4 now has two openings 6 arranged in a cover plate 7, where the cover plate 7 covers the inlet opening 4 for the suspension to the filter chamber (tem 12 in Fig. 5).

Figure 4 shows a sectional view IV-IV in Fig. 3 of the state-of-the-art chamber filter element 1, which corresponds to Fig. 2 according to the state of the art. Here the feed opening 2 is shown once again, which opens into a large, open inlet cross-section 8. This inlet cross-section 8 now extends as far as the inlet openings 4 arranged on either side because there are no plate elements 5 here in the area of the inlet to the filter chamber (Item 12 in Fig. 5). The end of the plate element 5 in the area of the inlet openings 4 to the filter chambers (tem 12 in Fig. 5) is now far away from the feed opening 2 and has additional slants 9 that permit good deflection of the suspension into the filter chamber (Hem 12). Cover plates 7 with openings 6 are placed over the inlet openings 4 on both sides. The membrane (tem 11 in Fig. 5) is stabilized due to these cover plates 7, preventing the membrane from being deflected inadmissibly into the inlet opening 4. This reduces the risk of damage to the membrane {item 11 in Fig. 5) to a large extent. By dividing the inlet opening 4 into two openings 8, for example, in the cover plate 7, greater stabilization can be achieved. The filter cloth applied to the membrane surface and extending into the feed opening 2 is also clamped in place by the cover plate 7 and thus the filter chamber 12 is also sealed off towards the feed opening 2. As the membrane can now no longer be pressed into the inlet cross-section 8, or only to a greatly reduced extent, the suspension also cannot be compressed so much as to be excessively compacted. Thus, & the suspension remains free-flowing at all times in the area of the inlet opening 4, even during pressing, and thus cannot block the inlet cross- section 8, guaranteeing that the suspension can continue to pass through.

Figure 5 shows the combination of two membrane filler elements 10 with a 10 chamber filler element 1. Here each membrane filter element 10 has a membrane 11 on either side. Filter chambers 12 are formed between the membranes 11 and the chamber filter element 1. In addition, a filter cloth is clamped to the chamber filter element 1 by means of a clamping plate 13 designed as a frame and extending round the feed opening 2 on 15 the one hand and the inlet opening 4 on the other hand. As a result, the areas of the feed opening 2 on the one hand and of the inlet opening 4 on the other hand remain open for the suspension flow to pass through. The clamping plate 13 used here can be made of metal or of plastic, for example. The other items are the same as those in the preceding figures. 20

The measures proposed can thus be implemented to avoid plugging of the inlet, as occurring so far in the state of the art, as well as preventing the fack of filling of the chambers, with the resulting reduced throughput in subsequent press cycles. This leads to constant throughputs and fonger 25 service life of the membrane filler elements, which in fur resulis in less filter press downtime.

Claims

1. Chamber filter element for a filter press with several filter slements, where each two membrane filter elements (10) with a chamber filter element {1} in between are joined fo one another with sealed edges and form filter chambers (12) between the chamber filter element (1) and the membrane filter element {10) into which an inlet opening (4) leads for the suspension fed in through the chamber filter element (1) and which is to be filtered, characterised by an open inlet cross-section (8) from the inlet opening (2) to the filter chambers (12) arranged on sither side being provided in the chamber filter element (1).

2. Chamber filter element according to Claim 1, characterised by the chamber formed in the chamber filter element {1} by the open inst cross section (8) being closed off at one of its ends by a plate element {5} that can be slanted (9) on both sides.

3. Chamber filter element according to Claim 1 or 2, characterised by a cover plate (7) being placed round the inlet opening (4).

4. Chamber filter element according to Claims 1 to 3, characterised by the inlet opening (4) being divided into more than one opening, for example two openings (8).

5. Chamber filter element according to Claim 3 or 4, characterised by the cover plate (7) being slanted,

6. Chamber filter element according to Claim 8, characterised by the cover plate (7) being made of metal or plastic.

7. Chamber filter element according to one of Claims 1 to 8, characterised by the inlet opening (2) at the lower end of the chamber filter element (1) or membrane filter element (10) being arranged at its upper end or in a comer of the elements (1, 10).

8. Filter press with chamber filter elements (1) according to one of Claims 110 7.