FI76001B - BLAD FOER EN SKIVFILTERS SEKTOR. - Google Patents

Description

76001

WHEEL FILTER SECTOR BLADE - BLAD FOR END SECTORS

The present invention relates to a blade for a disc filter sector comprising a flow-permeable body and channels for further flow therein, and a wire attached to the body which passes through the filtrate but retains, for example, a fibrous cake.

Disc filters are commonly used to remove fibers from water, with a plurality of discs sequentially attached to the rotating shaft, which are divided into functionally independent, hollow filtration sectors. Each sector is connected via an opening at the base to the interior of the shaft, to which a vacuum is applied. As the sector sinks into a basin with a fibrous suspension to be filtered, a layer of fibers begins to precipitate on the mesh surface of the sector as a result of the vacuum inside the shaft as it drains into the substantially shaft-long channel located inside the shaft. As the disc filter rotates, all axially successive filtering sectors in the same angular position discharge their filtrate into the same channel through which the filtrates are removed.

The blade of the disc filter sector is currently most commonly made of plastic, comprising a grate surface and filtration channels between two grate surfaces leading to the central axis of the filtrate filter, through which the filtrate is sucked into the tank, and most commonly a wire bag pulled over the platform. On top of the wire bag there is a so-called a fibrous cake which separates from the suspension as it is sucked through the central shaft and the filtration channels by a vacuum pump into the filtrate tank. As the disc rotates, the cake deposited at the edges of the sector is "worn" thin, so that its removal by means of a water jet is incomplete, because the cake does not "tear" evenly along the edge of the section, but part of the cake remains in the cake removal chute. The non-detachable part of the cake may come off the filter basin, where it interferes with the formation of the cake due to its abrasion effect. The non-tearable or non-detachable part of the cake reduces the capacity of the filter and, as an uncontrolled event, causes driving disturbances such as clogging of the discharge chute.

The object of the present invention is to provide a blade of a disc filter sector which does not have the above-mentioned drawbacks, but in which the cake is completely detached from the cake discharge chute. The pallet of the disc filter sector according to the invention is characterized in that a strip rising from the plane of the wire is arranged on the wire, on both sides of the pallet, at least on one edge of the pallet.

A preferred embodiment of the invention is characterized in that the strip is substantially L-shaped, extending to one side edge of the blade in a substantially radial direction of the disc filter and to the lower edge of the blade in a substantially tangential direction.

Another preferred embodiment of the invention is characterized in that the shorter prong of the L-shaped strip is made to widen towards its base, the inner angle between the shorter and longer prongs of the L-shaped strip being more than 90 °.

Another preferred embodiment of the invention is characterized in that the edge of the strip forms an angle of 45-135 °, preferably 90 °, with respect to the plane of the wire.

The steep, liquid-impermeable strip according to the invention at the edge and base of the pallet controls the tearing of the cake and ensures that the entire cake comes off the discharge chute. As a result, the filter capacity remains within the design values and driving interference is reduced. The strip can also be used as a lifting bar, e.g. in a situation where the formation of cake on the disc has stopped. In this case, the thickened pool goods can be lifted from the honeycomb to the discharge shaft by means of the list 3 76001.

In the following, the invention will be explained in detail by means of preferred exemplary embodiments with reference to the accompanying drawings, in which

Fig. 1 shows the disc of a disc filter according to the invention in the direction of its axis of rotation.

Fig. 2 shows the blade of the disc filter sector according to the invention enlarged.

Fig. 3 shows fig. 2 blades as seen from the side.

Fig. 4 shows a section of Figs. 2 along lines IV-IV.

Fig. 5 shows the same as Figs. 2, but the list is now on the opposite side of the stage.

Figure 1 shows a rotating disc filter in a fiber-containing suspension 10 and in particular a disc thereof. The disc is formed with a plurality of sectors 6, which disc rotates in the direction of arrow A will go through the steps 1-4. In step 1, the fibrous layer in the liquid is deposited on the reticulated surface of the sector. In step 2, drying of said fiber layer and emptying of the central shaft slot takes place. In step 3, the fibrous layer is detached from the surface of the sectors and finally in step 4, the mesh of the sectors is washed. As a net fabric or wire, so-called disc filter bags which are pulled over a sector or pallet and closed, for example, by a zipper on the side.

Each sector or blade 6 is provided on both sides with a strip 7. In Figure 1, only two sectors are plotted with a strip, but in reality each sector should have a strip. In this exemplary embodiment, the strip is substantially L-shaped, extending to one side edge of the pallet 4 76001 in the radial direction of the disc filter and to the lower edge, i.e. the base, of the pallet 6. At the base, the list is wedge-shaped, as can be seen from Figure 2. It tapers towards the tip. The strip is 1-10 mm thick, preferably 4 mm. Its side edge forms an angle of 45-135 ° with the plane of the platform, preferably 90 °.

Thus, Figure 1 shows a disc filter operating on the so-called over-pouring principle. In other words, the fibrous cake is removed from the surface of the sector only in step 3, i.e. shortly before the sector is pressed back into the suspension 10 in the basin 9. In this case, the strip 7 is arranged in the direction of rotation of the disc at the trailing edge. When removing the fibrous cake from the surface of the pallet, a jet of water or compressed air 8 is applied to the upper edge of the strip 7 on both sides of the pallet 6 (see especially Fig. 3). In this case, water or compressed air flows along the edge of the strip 7. In the overflow disc filter according to Fig. 1, the shower removes the cake first from the outer edge and finally from the side of the steep edge, whereby the cake comes off as a whole plate.

Fig. 5 shows the blade 6 of the disc filter sector, in which the strip 7 is arranged in Figs. 2 compared to the opposite edge of the platform. Such an arrangement is used in the disc filter discharging on the rising side, whereby the removal of the cake takes place during step 2 marked in Fig. 1. Of course, the direction of the jet is then also different from that shown in Fig. 1. The shower is directed obliquely against the strip 7 at its upper edge.

It will be clear to a person skilled in the art that the invention is not limited to the exemplary embodiments presented above, but can be varied within the scope of the appended claims. Thus, the slats not only work to make it easier to remove the cake but can also be used as lifting rods.

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Claims (5)

76001 A blade (6) of a disc filter sector, comprising a flow-permeable body and channels for further flow therein and a wire attached to the body which passes through the filtrate but retains, for example, a fibrous cake, characterized in that on the wire, on both sides of the blade, at least a strip (7) rising from the plane of the wire is arranged on one edge. Disc blade sector blade according to claim 1, characterized in that the strip (7) is substantially L-shaped, extending to one side edge of the blade (6) in a substantially radial direction of the disc filter and substantially lower tangential to the lower edge of the blade. Disc filter sector blade according to Claim 2, characterized in that the shorter prong of the L-shaped strip (7) is made to widen towards its base, the inner angle between the shorter and longer prongs of the L-shaped strip being more than 90 °. Disc blade of the disc filter sector according to one of Claims 1 to 3, characterized in that the edge of the strip (7) forms an angle of 45 to 135 °, preferably 90 °, with respect to the plane of the wire. Disc filter sector blade according to one of Claims 1 to 4, characterized in that the height of the strip (7) is 1 to 10 mm, preferably 4 mm.