FI66824C - FYLLKROPP FOER BIOFILTER ELLER FOER ANVAENDNING VID AEMNESOEVERFOERING - Google Patents

Description

1 66824

Filler used for biofilter or mass transfer.

- Filtkropp för biofilter eller för användning vid ämnes-överföring.

The present invention relates to a biofilter or mass transfer filler having one or more, preferably concentric, circumferential surfaces along which drainage of a liquid or gas to be cleaned is brought into contact with another medium, e.g. oxidizing air, which drainage surfaces are about 1 to 50 °, preferably 5 At an angle of -15 ° to the vertical axis of the filler, forming large wet surfaces, and the diameter of the filler being greater than the height.

The operation of a biofilter is based on the action of microorganisms that take place on the surface of the filler in the filter. The wastewater to be treated is evenly distributed on the filler pieces on top of the biofilter. Wastewater drains down the surface, coming into effective contact with the air flowing upwards.

The biofilter can be used as a pre-treatment step or as an actual biological treatment depending on the load. The biofilter system can be supplemented with chemical treatment.

In the past, mainly crushed-filled filters were used, but they have become obsolete mainly due to their low power, risk of clogging and high weight.

Until now, the wider use of biofilters has been hampered by the high cost of filter material. However, plastic fillers have changed this situation and made the use of biofilters more affordable.

British Patent 1,498,360 describes a plastic infill piece consisting of a cylindrical body 66824 provided with a plurality of nested obliquely mounted ring elements. Since these fillers are intended to be added to the filter tank completely randomly, the ring elements are provided with relatively large holes and notches so that the liquid can flow as freely as possible through the layer formed by the fillers. However, this means that not very large uniform surfaces are formed in each filling piece, along which the liquid could flow in contact with the oxidizing air.

British Patent Specification 1,439,745 also discloses a filter filler body consisting of a tubular body with various intermediate and filler members, the wall of which may be perforated. The length of the tube is relatively large, so its placement in the filter may cause flow obstructions.

In addition, our Finnish patent publication 62,274 discloses a disc-shaped filling piece with several concentric circumferences, the central part of which is thicker than the edge parts. This known filling piece settles very well in an almost horizontal position, whereby the drainage surfaces formed by the circumferences are set at an advantageous angle to the liquid flow.

It is now an object of the present invention to provide a filler body which makes the best possible use of the space of the washing tower and which seeks to prevent the channeling of liquid flows.

The infill according to the invention is characterized in that indentations are arranged in the upper and lower sides of the infill substantially in the central region of the aperture, whereby the height of the infill decreases towards its central part, giving the infill a flattened shape. This solution provides

II

66824 infill to settle almost completely horizontally. Due to the indentation, the drainage surfaces of the overlapping fillers are not in full contact with each other. In this way, interruptions are obtained in the liquid flow, which prevent the unwanted channeling of the liquid flow.

The drainage surfaces of the filler are helically connected to form a uniform surface. With such an arrangement, the largest possible uniform drainage area is obtained and the wet surface of the body becomes considerably large.

The efficiency of the filling piece can be further increased by treating the drainage surfaces differently, the surfaces can be roughened, patterned, grooved, provided with embossments, protrusions or ribs. They can also be perforated or notched or provided with various openings. Of course, it is also possible to combine two or more of the above-mentioned surface patterns.

The invention will be described in more detail with reference to the accompanying drawings, in which Figure 1 shows a filler according to the invention in cross-section, Figure 2 shows the filler of Figure 1 seen from above, Figures 3 and 5 show embodiments of the invention in cross section, Figure 4 shows an embodiment according to the invention helical filling piece 4 66824

Figure 7 shows a different surface pattern.

Figures 1 and 2 show the main principles of the infill according to the invention. The filling piece consists, seen from above, of a disc-shaped body with an outer circumference 1 and an inner circumference 2 connected by radial connecting ribs 4. The outer circumference 1 is further provided with radial support ribs 3 located between the connecting ribs 4. The ribs 3 and 4 extend beyond the circumference 1 and their protruding part 5 is rounded. The ribs 3 and 4 also form the outline of the body when viewed in cross section. In the embodiment according to Figure 1, the height of the body decreases towards the outer circumference, forming indentations 8 on the upper and lower side of the filling body.

The perimeters 1 and 2 are mounted at an oblique angle to the vertical axis so that the liquid to be cleaned can flow both above and below the surfaces 1 and 2, so that the entire surface of the perimeter can be utilized as efficiently as possible. The angle of inclination is 1 to 50 °, preferably 5 to 15 °, which has been found in the experiments performed. If the angle of inclination is much larger, the liquid flow will detach below the surface, especially at high flows, whereby the wet surface will naturally decrease.

Figure 3 shows a cross-section of another embodiment according to the invention, in which the disc-shaped filling piece is provided with two additional circumferences 6 and 7 in addition to the outer and inner circumferences 1, 2. The connecting ribs 4 and the support ribs 3 project from the outer circumference 1 by a rounded part 5.

Figure 4 shows a filling piece, the circumferential shapes of which are rectangular, the outer and the inner circumference 1 and 2 being connected in this case also by connecting ribs 4, the ends of which have rounded parts 5 projecting from the outer circumference 1.

• Γ 66824

However, the embodiment shown in Fig. 5 corresponds to the infill of Fig. 3, so that the upper and lower edges of the drainage surfaces 1, 2 and 6 and 7 are provided with circumferential upward and downwardly opening troughs 11, 12. The purpose of these troughs is to improve liquid distribution in the infill.

Figure 6 shows an embodiment of the invention, in which the filling piece is shown from above. In this application, the drainage surfaces are combined into one continuous surface which is given a helical shape 13.

Figure 7 shows three different surface patterns. This surface pattern aims to enhance the contact of liquids or gases and liquids in the filler. The casting surface of the filling piece can either be provided with the pattern shown in Fig. 9, i.e. with different teeth, notches or grooves. It is also possible to roughen the drainage surfaces.

Thus, only some applications according to the invention have been presented in the presented solutions. However, the shape of the filling piece may differ from that shown, for example in terms of its shape and the number of frames and the number of connecting and supporting ribs. Preferably there are 1 to 5 rings, but there can of course be more. In the applications shown, the slope of the frames is opposite in adjacent frames. It is, of course, possible to arrange so that the circumferences are parallel.

The filler according to the invention is intended to be used in biofilters, but the fillers can, of course, be used for mass transfer in general, e.g. in various gas scrubbers.

Claims (3)

66824 A biofilter or transfer device filler having one or more, preferably concentric circumferences, along the drainage surfaces of which the liquid or gas to be cleaned is brought into contact with another medium, e.g. oxidizing air, which drainage surfaces are about 1 to 50 °, preferably 5 to 15 ° at an angle to the vertical axis of the filler, forming large wet surfaces, and the diameter of the filler being greater than the height, characterized in that indentations (8) are arranged on the top and bottom of the filler substantially in the center of the body, reducing the height of the filler towards its center . Filling piece according to Claim 1, characterized in that the drainage surfaces are helically connected to form a unitary surface (13). Filling piece according to Claim 1 or 2, characterized in that the drainage surfaces are surface-roughened or surface-patterned. Il