NO179280B - Contact material for the treatment of liquids and process for their preparation - Google Patents

Abstract

A filler and a process for producing it, where the filler, in the case of the biological treatment of sewage, should in particular exhibit a "biological meadow" which is necessary for this purpose, and a uniform moistening ability. In the case of known fillers which consist of strips, it has been found that the strips straighten under influence of encrustation and thereby form a pore foothold for the "biological meadow" and seek to become attached to each other. The purpose of the novel filler is to eliminate this drawback, and for it to be easy to manufacture and install. The novel filler exhibits at least one tensile member (fibre 29), which has been located beside the strips 20. When suspended, this takes up the load such that the strips 20 are essentially unloaded and thereby retain the shape they were given during manufacture. The filler is especially suitable for the biological treatment of sewage and drinking water, i.e. denitrification. <IMAGE>

Description

The invention relates to a plastic contact material for handling liquids according to the preamble of claim 1. The present invention also relates to a method for producing contact material for biological water purification according to the preamble of claim 9.

The contact material mentioned here serves above all for biological treatment in waste water technology. In this connection, the contact material serves as a carrier for the bacteria necessary for the biological treatment, namely as a so-called biological lawn. The performance of a water treatment plant equipped with such a contact material depends on a number of factors. On the one hand, the contact material must provide the largest possible specific growth surface, while on the other hand, the best possible attachment of the bacteria to the contact material is required. Finally, the biological lawn on the contact material must be able to be penetrated or moistened by the liquid to be treated without hindrance.

The known contact material of the type indicated in the introduction, i.e. a contact material of a number of plastic strips has the disadvantage that the smooth strips have a tendency to stick together, whereby the liquid to be treated cannot flow between the biological lawn of adjacent strips. The efficiency of a water treatment plant equipped with this is thus significantly reduced.

In order to avoid the above-mentioned disadvantages, in the older European patent application no. 274 633 instructions have been given for a contact material whose strips on opposite edge areas are provided with vaults. In the middle, the strips have a smooth course. Thereby a neutral area is provided in the middle of the strips and which serves to absorb the weight of the moistened strips. In this connection, however, it has been shown that due to the weight load of the strips, these eventually become smooth-stretched as a result of the biological lawn that settles on the strips, so that even these gradually stick together.

In addition, it has proven to be expensive to form drip filters from the known strip-shaped contact material, as the suspension of the strips on a suitable carrier device can only be carried out with difficulty with the even distribution required for an optimal effect over the entire drip filter.

With this starting point, the purpose of the invention is to provide an effective and easily mountable, strip-shaped contact material as well as a method for simple production thereof.

In order to achieve this purpose, the contact material according to the invention has the features that appear in claim 1. By arranging at least one stretching member on each strip, it is achieved that this does not stretch under the load of the biological lawn growing on it and because of this is smoothed like this that an easy joining of adjacent strips is obtained. On the contrary, it has surprisingly been found that strips provided with at least one tension member twist under the action of a load. A joining of adjacent strips is therefore practically no longer possible.

Appropriately, the tension members are made as a stretch-absorbing (round) string running in the longitudinal direction of the strips. This can be easily produced and practically does not affect the fouling of the strips.

It has proven particularly advantageous to assign each strip a single (central) strand. The strips reinforced in this way bend under load around the string which, so to speak, forms a longitudinal central axis for a spiral.

According to a further, significant proposal of the invention, each of the strings is connected to the strips belonging to it in such a way that in the case of stretched (straight-lined) strings, the strips thus connected have a wavy or wave-like shape in the smallest areas of their opposite edges. Thus, it is ensured by the strain-absorbing strings that even when the strips are loaded, the strips retain this shape, as the strings prevent an expansion and thus a smoothing of the strips.

The method according to the invention has the characteristics that appear in claim 9. According to this, the threads which serve to stabilize the strips are first produced separately and then connected to the strips. The strands are thereby, in contrast to the strips, still at least in a warm state. This achieves, firstly, that the still warm or hot strands are glued together or welded without gluing or other finishing measures. On the other hand, during the cooling, the plastic strands and the resulting shrinkage of these, the cold, i.e. no longer shrinking strips, are crimped. This ripple, which serves to raise the specific growth surface and is therefore desired, thus occurs with the method according to the invention as an additional benefit without special measures.

According to the method, it is also proposed to simultaneously seal a series of strands on a web which serves to form a larger number of strips lying next to each other and after the cooling of the strands to divide the web by means of successive separation cuts between two adjacent strands to form wood strips lying next to each other. This method enables a high production capacity as a number of adjacent strips can be produced at the same time.

Furthermore, it is proposed to form the attachment web which serves to join the adjacent strips by making the separation cuts to form the adjacent strips from the web, at regular intervals. The fastening strips are thus formed in the simplest way by the path that serves to form the strips being unchanged in the area of the fastening strips. This results in a significant simplification of the production of the contact material according to the invention.

Finally, in connection with the method, it is also proposed that several lanes are joined to obtain a larger, independently manageable unit with a relatively large number of 7 * J independent strips. For this purpose, several webs are brought together, and after cutting the individual strips, they are attached to their holding strips, preferably by welding. Thus, a considerable number of strips can be joined together and mounted as a whole on a carrier frame or the like for the drip filter.

Design examples of the contact material according to the invention and equipment for producing this are explained in more detail below, in connection with the drawing. Fig. 1 shows a section of a drip filter with contact material suspended over a support frame. Fig. 2 shows a plan of the contact material according to fig. 1. Fig. 3 shows an enlarged, plan view of a section of a single strip of the contact material. Fig. 4 shows a cross-section through the strip according to fig. 3.

Fig. 5 shows a side view of the strip according to fig. 3.

Fig. 6 shows a floor plan of a further design example of contact material. Fig. 7 shows an enlarged plan view of a section of a strip of the contact material of Fig. 6.

Fig. 8 shows a side view of the strip according to fig. 7.

Fig. 9 shows an apparatus for placing strings on a (material) path which serves to form a number of strips. Fig. 10 shows an apparatus for cutting the strips from the (material) web and for joining together several superimposed webs.

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Fig. 11 shows an alternative design example of the device according to fig. 10 for the production of the strips according to the embodiment in fig. 6-8.

The contact material shown in the design examples serves as a drip filter for biological water purification.

Fig. 1-8 show embodiments of the contact material in which a series of longitudinal strips 20 lying next to each other are connected to each other by means of a transverse fixing path 21 in the middle. The individual strips 20 of the contact material are here arranged in three superimposed layers 22 respectively 23. As shown in fig. 2, the two outer layers 22 have the same number of strips 20. Also the arrangement of the strips occurring in the outer layers 22 is approximately the same. In contrast, the middle layer 23 has a number of strips 20 which is reduced by one strip 20. Thus, the strips 20 in the middle layer 23 can be arranged offset in relation to those in the two outer layers 22 in such a way that the strips in the middle layer 23 lies in the middle between two strips 20 in the outer layer 22, i.e. above a "gap". The length of the strips 20 is approximately the same in each layer 22 and 23.

As can be seen in fig. 2, the strips located on opposite end areas 24 and 25 of the fastening web are connected in one piece with the fastening web. For this purpose, the fixing web 21 is formed with the strips 20 assigned to it into a common (material) web 26 which, in the areas adjacent to the fixing web 21, is provided with continuous incisions 27 for the formation of the strips 20. Consequently, they are next to each other horizontal strips 20 are each separated from each other by an incision 27 which extends throughout from the free ends 28 of the strips 20 to each end area 24-25 of the holding track 21.

In the present embodiment, as can be seen in fig. 1-5, each strip 20 assigned to a tension member, namely a string 29. As is particularly clear from fig. 2, in each case a straight string extends from the free end 28 of a strip 20 located on one side of the fixing web 11 and to the (opposite) free end 28 of a strip located on the other side of the fixing web 21. Thus, in each case, a string 29 connects two opposite strips 20 in that they extend uninterruptedly across the fastening web 21. The arrangement of the strings 29 is such that they are located on one side and in the middle of the strips. This can clearly be seen from fig. 4. As can again be seen from fig. 2, each of the layers 22 and 23 has as many parallel strings 29 as they have adjacent strips 20.

As can also be seen in fig. 2, but also on fig. 1, the (end) areas of the strips 20 directed towards the fastening web 21 are provided with incisions 30. These are made roughly rectangular and each lie between two adjacent strips 20, so that in the areas of the incisions 30 the strips have a reduced width, without however, to break the strings 29. The incisions 30 serve, when they. is suspended on a support beam 31 of a support frame 32, so that the liquid that is dripped from above onto the drip filter can reach the strips in the middle layer 23 or to the outer layer 22 which faces the support beam 31, i.e. to ensure uniform wetting of the strips 20 in all layers 22 and 23 respectively.

As can also be seen in fig. 1, the different layers are 22 or 23 connected to each other in the central area of their attachment webs 21 with a welding seam 33 running respectively in the longitudinal direction of the attachment web 21 and across the strips.

In fig. 3-5 it can be seen that in contrast to the string 29, which extends in an approximately straight line, the strip 20 is crimped and namely such that it has folds 34 which extend across the longitudinal direction. The parallel edges 35 of the strip 20 therefore have a particularly clear in fig. 5 visible wavy course. This gradually decreases from the edges 35 to the (middle) string 29. In this embodiment, the strips 20 get a three-dimensional structure which is an optimal surface for the "biological lawn" which is to be grown on it for biological water purification. I J\ J£. kj\ J

In the embodiment shown, the string 29 has an approximately circular cross-section whose cross-section is considerably larger than the thickness of the material in the strips. As material for the string 29 comes a thermoplastic material with low stretchability, e.g. polypropylene or polyethylene, in consideration. Thus, the strips, supported by the strand 29, substantially maintain their length in the loaded state, i.e. with the "biological lawn" growing on the surface of the strip 20 to prevent the smoothing of the strip 20, especially its wavy edges 35.

In contrast to that in fig. 1-5 described contact material has the contact material shown in fig. 5-7 seen in plan view snake-like, namely sinusoidal strips 36. These can, as fig. 5-7 shows, also on one side be provided with a string 37 running in a straight line. For this purpose, the strips 36 in the present embodiment extend alternately to one and the other side of the (straight-lined) string 37, so that it is ensured a continuous contact of the strip 3 6 with the string 37. Alternatively, it is also conceivable to let the string follow the snake line of the strip, whereby the string also then takes on a snake-like course.

As can be seen in fig. 8, in the embodiment shown, the parallel, winding edges 38 of the strip 36 are rippled, so that these also have a wave-like course. Such a strip 3 6 has a large spatial distribution which provides particularly large growth surfaces for the "biological lawn". Alternatively, with the snake-like strips 3 6 shown here, it is conceivable to dispense with the corresponding strings 37.

An apparatus for producing the strings 29 and joining them with a (material) path 26 which serves to form the strips 20 is shown in fig. 9. With the device shown, a number of separate, side-by-side strings 29 are produced with an extruder 39. The strings 29 that come out of a nozzle 40 on the extruders 39 are still in a hot state, i.e. close to the nozzle 40, when they are fed together with the cold (material) path 26 and welded together or sealed. For this purpose, the (material) web 26 is pulled by a supply coil 41 and passed between suitable pairs of rollers, namely in the present embodiment three pairs of rollers 42, between which also the strands 29 coming out of the nozzle 40 on the extruder 39 and still hot pass. Thereby, the strings 29 are welded together with the (material) web by passing the strings 29 and the (material) web 26 through the roller pairs 42.

After the roller pairs 42, the (material) web 26 supplied with the strings 29 is led through a cooling station 43. This cooling station 43 has a number of support rollers 44 located on the underside of the (material) web 26 and one on the opposite upper side of the (material) the path 26, where the strings 29 are located, assigned to cooling device 45. With the cooling of the strings 29 occurring in the cooling station 43, these shrink. Thus, the cold, i.e. non-shrinking (material) web 26 contracts, so that it especially gets the ripple that appears at the edges 3 5 .

After the cooling station 43, the rippled (material) web 26 provided with strings 29 is thus wound up on an intermediate storage coil 46. The (material) web 26 thus produced can then be further processed on a in fig. 10 shows apparatus for forming the final contact material.

In the design example in fig. 10, the further processing of the (material) web 26 provided with the strings 29 takes place first in three planes. In this connection, at the same time the (material) web 26 provided with the strings 29 is pulled by three intermediate bearing coils 46 arranged above each other. In this connection, the strips 10 and 20 are first cut on each (material) web 26, when each (material) -)web 26 is moved past a sheath unit 47 to form the (straight-lined) incisions 30 between adjacent strips 20. The sheath units 47 can be lifted from time to time by means of a lifting device, not shown, so that they can be removed from (material) the path 26 to form in such cases

(uncut) fixing lanes 20. ' °

After the sheath unit 47 for each (material) web 26, the apparatus has corresponding punching devices 48. These punch out the notches 30 between adjacent strips 20. To ensure continuous production, the punching stations 48 can be of the flying type.

Behind the punching stations 48, all wood with incisions 27 and 30 supplied (material) paths 26 are brought together, by the two outer layers 22 being passed between a pair of rollers 50 over transfer rollers 49 at the middle, inner layer 23. Seen in the direction of production (arrow 51), following the pair of rollers 50 is a welding device 52. This serves to join layers in the layers 22 and 23 respectively in the area of their holding tracks 21 to form the welding seam 33. Accordingly, the welding device 52 is activated periodically, namely every time three overlapping holding tracks reach 21 for the layers 22 and 23 are located in the area of the welding device 52.

Seen in the direction of production, the welding device 52 has a last pair of rollers 53 and a transfer roller from which the contact material with units hanging behind each other is wound onto a stock spool 55. From this the individual contact material units for the assembly of drip filters 11 are pulled off one after the other and can be placed on ., ie support beams 31 in the support frame 32.

At least one of the roller pairs 50 or 5 3 on the apparatus can be driven in rotation to draw the (material) web 26 which is to be finished processed through the cutting unit, the punching unit and the welding device.

Alternatively, it is conceivable to leave it on fig. 10 showed the apparatus section following immediately after the first apparatus section in fig.

9. In this case, the winding of the (material) web 26 supplied with strings 29 on the intermediate bearing coil 46 is therefore omitted. This alternative is particularly suitable for the production of contact material from a single-layer (material) web 26. But also a multi-layer contact material can be produced fullsterifti^-S?w subsequent steps, if namely the individual layers 22 resp. 23 is simultaneously produced on several extruders 39 etc.

Finally, fig. 11 an alternative to that in fig. 10 showed apparatus. It is particularly suitable for the production of snake-shaped strips 3 6 according to fig. 6-8. The waves of the snake-shaped strips 3 6 are here formed by a cutting device 5 6 with a thermo-cutting pin, knife blade, cutting roller or a similar arrangement which during the continuous advancement of the (material) path 2 6 in the production direction 51 is regularly moved back and forth on across this. This orthogonal superimposition of the direction serves to easily form parallel, wavy edges 38 on the strips 36.

Claims (13)

1. Plastic contact material for treating liquids, especially for biological water purification, with a number of strips (20, 36) of plastic, characterized in that the strips (20, 36) have at least one stretch-absorbing string (29, 37). 2. Contact material according to claim 1, characterized in that on the strips (20 and 36) in the longitudinal direction of these, a stretch-absorbing string (29,37). 3. Contact material according to claim 1 or 2, characterized in that a single string (29) is arranged approximately in the middle on one side of each strip (20) which is provided with straight parallel edges (35). 4. Contact material according to claim 1 or 2, characterized in that a single, roughly straight string (37) is arranged on one side of each strip (36) which is provided with equal, wavy, parallel edges (38), on such a way that the string extends in a straight line over the entire length of the strips (3 6) between their wavy edges (38). 5. Contact material according to claim 1 or 2, characterized in that the strain-absorbing string (37) is firmly connected to the strips (36) in such a way that in the case of a string (37) that extends in a straight line, the strips (36) which is connected with this, the mug. 6. Contact material according to one or more of claims 1-5, characterized in that the stretch-absorbing string (29, 37) is firmly connected to the strips (20, 36). 7. Contact material according to one or more of claims 1-5, characterized in that the string ^ 29i^ Yr^ has an approximately round cross-section, so that the diameter of the string (29, 37) is several times greater than the thickness of the strips (20, 36 ). 8. Contact material according to claim 7, characterized in that the strand (29, 37) preferably consists of a thermoplastic material with low stretchability, e.g. polypropylene or polyethylene. 9. Method for the production of a contact material used for biological water purification according to claims 1-8, characterized in that several continuously produced (extruded) strands (29,37) under the influence of heat, at least in a hot state, are continuously placed on a (material -) web (26), and that the material web (26) is cut continuously between adjacent strings (29, 37) to form strips that lie next to each other. 10. Method according to claim 9, characterized in that a number of hot strings (29.37) are sealed or welded onto the cold (material) path (26) under pressure. 11. Method according to claim 9 or 10, characterized in that after sealing or welding of the strings (29,37) onto the (material) web (26), the web is led together with the strings (29,37) through a cooling device (45), in which the shrinking of the cooled strings (29, 37) a ripple of the (material) path (26) occurs. 12. Method according to claim 10 or 11, characterized in that the (material) web (26) after cooling of the strands (29,37) is in each case continuously divided between the adjacent strands (29,37), and that the cutting of the strips (20,36) from the (material) web (26) is interrupted at regular intervals to form the fixing webs (21) which connect adjacent strips (20,36). 13. Method according to claim 12, characterized in that after the strings (29,37) have cooled, the (material) web (26) provided with these is wound up on an intermediate bearing coil (46) and then - such (material )webs (26) simultaneously drawn from several intermediate bearing coils (46), cut and then connected to the attachment webs (21).