DE9006261U1 - Biological exhaust air scrubber for an animal stable - Google Patents

Description

Johann Schönhammer
Niederreuth 131
8317 Mengkofen

Biological exhaust air scrubber for an animal stable

The innovation relates to a biological exhaust air scrubber according to the preamble of claim 1.

Biological exhaust air scrubbers have packing elements that are located in a cleaning chamber, through which the stable exhaust air flows and are sprinkled with water from above, whereby a biological lawn in the form of a brown, slippery coating forms on the packing elements, which, together with the water, filters out odors and contaminants from the exhaust air. The chambers can be operated in countercurrent or crosscurrent. Ammonia, triethylamine and hydrazine are particularly mentioned as unpleasant odorous substances. The solids contained in the exhaust air are in particular dust from hair and rind abrasion as well as dust from stable bedding material. It is known (DE-GM 87 17 750, DE-OS 30 24 228) to provide several cleaning chambers through which air flows in a cascade, each containing a scrubber section. Ring structures with filament-like windings are known as fillers (DE-OS 32 17 923), for example, which are piled up on a floor grid in the individual chambers. With regard to the construction guidelines, reference is made to VDI guideline 3478 "Bioscrubbers".

Biological exhaust air scrubbers for stable exhaust air have also become known, the filling bodies of which are profile plates, the zigzag-shaped profile of which forms channels and webs on both sides, which, when the plates are placed together, become flow channels on whose surface the biological grass settles. These plate filling bodies are characterized by a particularly low pressure drop, with corresponding savings in ventilation energy. An example of an air scrubber

For a plate-filled compressor, it is stated that at an air velocity of 3 m/s a pressure drop of the order of 100 Pa results.

The gas washing function of the known air washers is basically satisfactory. However, difficulties arise if they are to be used for stable ventilation, as the solids and dust carried in the exhaust air lead to increased sludge formation and blockages, particularly in the entrance area of the exhaust air washer.

The innovation is intended to prevent this tendency to become clogged. This is achieved by the innovation characterized in claim 1, which preferably relates to an exhaust air scrubber with profile plates as filler and uses the division into several sections and possibly also multiple chambers in such a way that the lower sections or chambers of the exhaust air scrubber, which mainly filter out the solids from the exhaust air, are highly self-washing, while the sections or chambers downstream of the air flow mainly filter out gas and are less affected by solid deposits, so that the self-washing effect there does not have to be as high. The exhaust air scrubber is therefore kept sufficiently clean by the washing water that is generally circulated through it, or can be easily cleaned by special cleaning procedures that take place at intervals, in which it is removed and dismantled, or by splash water cleaning, depending on the fineness of its structure, where the solid deposit is high, while in places where the solid deposit is low, poorer cleanability can be accepted in favor of a better gas filter function.

When defining the innovation, it is assumed that the pressure drop in the individual cleaning chamber is inversely related to the washability. Plates with a lower pressure drop are easier to keep clean by the washing water, while finer structured plates that have a higher pressure drop

also show major problems with washability.

The different structures that lead to different specific pressure drops can be given by parallel or crossed grooves, larger or smaller groove cross-sections, straight or zig-zig grooves or even a stronger or weaker corrugation of the groove walls, as stated in claims 3 to 7. The measure according to claim 8 offers improved wall wetting options, since the undersides of the groove walls remain more easily wetted by a uniformly flowing layer of water.

The individual washer sections form layers of the entire air washer, which, depending on the design, can be integrated into a single block or distributed over several separate chambers or sub-blocks. In a multi-chamber design, additional water nozzles can also be installed for the inlet cleaning chambers, in particular if the chambers according to claim 10 are arranged one above the other in a manner known per se, with water flowing through them from top to bottom and exhaust air flowing through them from bottom to top.

The innovation is primarily designed for plate exhaust air scrubbers and is described using this preferred design. However, it is also applicable if loose individual packing elements with different individual structures are used in the chambers through which the exhaust air flows one after the other.

Further details, advantages and developments of the innovation emerge from the following description of preferred embodiments with reference to the drawing. They show:

Fig. 1 is a schematic, partially sectioned side view of an innovative biological exhaust air scrubber after installation in a livestock stable;

Fig. 2 is a schematic representation of a modified exhaust air scrubber;

Fig. 3 is a schematic representation of the profile plate structure of two cleaning chambers lying one above the other;

Fig. 4 is a representation corresponding to Fig. 2 of a modified embodiment of profile plates;

Fig. 5 is a view comparable to Figures 3 and 4 with four different cleaning chambers arranged one above the other;

Fig. 6 two cross-sections through profiled panels placed next to one another in a block in cutting planes perpendicular to the panel grooves, with different panel placement according to Fig. 2 or 3;

Fig. 7 Profile diagrams for three different profile plates serving as filler in the form of sections through the plate center plane corresponding to a cutting plane 7-7 in Fig. 6.

Fig. 8 shows an integrated block with several scrubber sections in a representation corresponding to Fig. 5.

According to Fig. 1, an exhaust air washer 1, which consists of two sections 2 and 3, each arranged in a cleaning chamber, is installed in a stable 4 and penetrates the stable ceiling 5. Below the chambers or sections 2 and 3 there is a collecting basin 6 in which washing water 7 dripping from the lower chamber is collected and pumped from there to water nozzles 8 and 9. Above the exhaust air washer 1 there is also a heat exchanger 10 of known design.

The structural details of the exhaust air scrubber 1, insofar as they correspond to the state of the art, are not described in detail here and are not shown in detail in the drawing, for example washing water pumps which pump the washing water 7 from

the collection basin 6 to the nozzles 8 and 9, a sludge pumping device, which transports accumulated sludge from the collection basin 6 into the slurry pit, or a level controller for the collection basin 6. Likewise, it is not shown how the air is pressed through the exhaust air washer 1 and the heat exchanger 10, be it by suction in the system shown (negative pressure ventilation) or by compressors in supply air ducts (positive pressure ventilation). The air is sucked in according to arrows 15 above the water level in the collection basin 6 into the underside of the cleaning chamber 2, whereby larger solid particles transported along are already partially caught by the water surface, and passes through the section 2, which is sprinkled with water from above by the nozzle 8, the space in which the nozzle 8 is located, and the washer section 3, which is supplied with washing water via the nozzle 9. The exhaust air is further sucked or pushed into the heat exchanger 10 and finally leaves it via a chimney 11.

A pressure difference is established in each of the chambers 2 and 3 as a proportion of the total pressure difference applied by the compressor (not shown). This pressure difference depends on how easily and straight, or how narrowly and frequently the gas is passed through the individual section. These properties also determine how strongly solids are held by the wet surfaces in the exhaust air scrubber and how gases to be filtered are adsorbed, and how easily captured solids are flushed out again.

In the embodiment according to Fig. 1, the chamber with section 2 is increasingly rinsed with washing water, since it has access to both the washing water dripping from the chamber with section 3 and the water exiting through the nozzle 8. Solids in the exhaust air are therefore preferentially captured and rinsed out in section 2. In addition, section 2 is designed for a smooth, low-friction air flow, which also makes it easier to rinse out and drain off the solids without creating sludge nests.

In contrast, section 3 has a finer flow structure, resulting in an increased pressure drop and a longer stay of the exhaust air in the corridors of this chamber, which leads to sufficient filtering out of harmful gases, while the generally feared build-up of entrained solid particles no longer plays a significant role as these have already been washed out in section 2.

The different structures of the packings in sections 2 and 3 will be described in detail later.

Fig. 2 shows a modified exhaust air washer 1' with four sections 21, 22 and 23, 24, each of which takes up one chamber, of which the chambers with sections 21 and 22 are arranged in a row and the chambers with sections 23 and 24 are arranged in a row, while these two row arrangements are arranged parallel to one another. They are located next to one another above the collecting basin 6, and the chambers with sections 22 and 23 have three-sided, drawn-down walls 25 and 26 on their outlet side, which extend into the washing water 7. The chambers 22 and 23 of the exhaust air washer 1' vent via a chimney 27 located between them, in which the compressor system (not shown) is also located in this version. An air supply opening 28 is visible in the stable ceiling 5. All chambers are supplied with washing water by two nozzles 8. In this design, the drip water from all chambers drops directly into the collection basin 6. In this design, sections 21 and 24 have a structure that produces a low pressure drop, and sections 22 and 23 have a structure that produces a higher pressure drop, so that sections 21 and 24 act as pre-scrubbers that wash out the solids and sections 22 and 23 act as main or post-scrubbers that filter out the harmful gases.

Fig. 3 and 7 show an example in which two superimposed chambers according to sections 2

and 3 according to Fig. 1, one possibility for the different design of these sections. The material of the sections, namely the fillers, are profile plates 30 made of a plastic film, each held in a frame, which in a transverse cutting plane forms a zigzag configuration of isosceles triangles, which form grooves 31 or webs 32 on the respective side of the plate. The apex lines of the ridges on one side are the groove bottoms of the other side of each plate (Fig. 6). The grooves 31 or webs 32 run diagonally from top to bottom with respect to the straight-cut edges 33, 34 of the plates. In section 2, the plates are placed together in such a way that groove 31 meets groove 31 and the apex of the web 32 meets the apex of the web 32 of the neighboring plate 30. In section 3, on the other hand, every second plate is turned around a vertical axis of rotation, so that in a single plate 30 shown at the front in Fig. 3, the channels and webs run from top right to bottom left, while those of the next one behind it run from top left to bottom right. The exhaust air flowing through the individual channels is therefore not provided with long, straight double channels with wet walls, as in section 2, but rather with individual channels that are open to the side against a cross flow, whereby the flow is constantly constricted by the webs 32 on the one hand and swirled and mixed between them by the cross flows in the channels crossing them on the other.

Fig. 4 shows plates 40 in which the channels, which are also designated 31 here, or the webs 32 run in zigzag lines from top to bottom. Again, in section 2, the adjacent plates 40 are joined together in such a way that channel 31 meets channel 31 and the exhaust air flows upwards through section 2 in double channels, but on a zigzag path, which, compared to section 2 in Fig. 3, shows even greater turbulence, and thus a greater pressure drop and an increased filtering effect, but also a slightly increased tendency for dirt to collect in sludge nests. However, this is still relatively

low, while in section 3 of Fig. 4 the channels 31 are again arranged crosswise, with corresponding consequences for pressure drop, air cleaning effect and tendency to blockage. Overall, the exhaust air washer according to Fig. 4 is suitable for exhaust air that is slightly less contaminated with solids than the one according to Fig. 3, but for which it provides an improved filtering effect with the same overall dimensions.

In the exhaust air scrubber according to Fig. 5, four chambers with scrubber sections are arranged one above the other, which are designated 2a, 2b, 3a and 3b. Section 2a corresponds to section 2 according to Fig. 3 and is constructed in the same way from plates 30. Section 2b corresponds to section 2 according to Fig. 4 and is constructed in the same way with plates 40. Section 3a corresponds to the structure according to section 2b, with plates 41 which, like plates 40, have zigzag grooves and webs, but these grooves 31 individually have a smaller cross-section and thus result in narrower, but more flow channels. In this case, for example, the groove depths can be smaller, so that more profile plates 41 are installed per section, or the grooves can have a narrower open side, so that the individual plate surface is more densely covered with grooves. In section 3b, the plates 41 are again arranged crosswise, i.e. as in section 3 according to Fig. 4, but with narrower flow channels. In this exhaust air washer, the pressure drop of the individual sections or chambers increases from bottom to top, the self-washing ability of the chambers decreases from bottom to top and the fineness of the air purification increases from bottom to top.

In the sense of such a staggering, other combinations are also possible, for example, if there are four sections, two of them can be the same, or sections 2b and 3a can be the same, etc. Furthermore, as in the examples shown, the chambers can each contain a scrubber section, or the cascaded sections can be integrated into a single block and arranged in a common chamber.

as shown schematically in Fig. 8, or may also be arranged in other sub-combinations.

In the arrangement according to Fig. 5, additional washing water is again introduced along the height of the system, namely between the chambers 2b and 3a. The exhaust air scrubber contains nozzle bars 8 ¹ and 9 ¹ , which are arranged in the middle and on the top of the cascade respectively. If the gaps are smaller, relatively wide-spraying nozzles must be installed, which are also designed in such a way that they do not become blocked by solid particles settling. In the case of an integrated block, intermediate spray nozzles are no longer possible so easily, but this has the advantage of an overall reduced space requirement.

Another possibility of influencing the pressure drop with a significant influence on the air washing effect and the self-cleaning effect is by corrugating the walls of the channels 31. In Fig. 7, in a sectional plane that is drawn in the cross-sectional representation of the plates in Fig. 6 transverse to the channels and webs (6a), various designs of corrugations are shown in representations 7a, 7b and 7c.

According to Fig. 7a, the channels 31 have alternating widenings and narrowings. The exhaust air passing through is thereby disrupted in its continuity of flow and swirls to a certain extent, which improves the air contact with the wetted wall of the channel covered with biological turf. The pressure drop can be selected differently by varying the degree of waviness.

According to Fig. 7b, the cross-sectional area always remains constant, but the flow path is deflected several times. This also leads to turbulence. The construction according to Fig. 7b could, in the described embodiment, have the consequence that water drainage grooves 44 are formed on the upper sides of the channels, which drain the water from the side surfaces and accelerate it to the tops of the webs 32, while

Water drip edges 45 can form on the undersides, which also cannot be easily overcome by the thin stream of liquid flowing along the surface. These disadvantages can be avoided by installing the profile plates with steeper grooves 31 or webs 32.

Fig. Ic shows another construction with channel side walls that protrude upwards in a bulge shape, but are flatter on the uphill side than on the valley side, and are smooth on the underside. In practice, this can be achieved by covering the open undersides with a second film. This results in a good wetting and swirling effect while at the same time avoiding the formation of mud nests and blockages as far as possible.

Claims (11)

11 Protection claims 1. Biological exhaust air scrubber for an animal stable, with several scrubber sections (2, 3; 2a, 2b, 3a, 3b) arranged in a cascade, in which filler bodies (30, 40, 41) are arranged, above which there are water outlet nozzles and at least one exhaust air connection and below which there is a water collection basin (6) and in turn at least one exhaust air connection and which can be wetted by the downward-flowing water and through which the exhaust air can flow, producing a pressure drop, characterized in that in the section(s) (2, 2a) through which the exhaust air flows first, the filler bodies (30) are arranged to produce a lower pressure drop than in the section(s) through which the exhaust air flows later. 2. Exhaust air scrubber according to claim 1, characterized in that the filling bodies consist of profile plates (30, 40, 41) which are held in a frame generally parallel to one another in a substantially vertical position and whose profiles form obliquely downward-running channels (31). 3. Exhaust air washer according to claim 2, characterized in that in the section(s) through which the exhaust air flows first (2, 2a, 2b, 3a) the profile plates (30, 40, 41) are arranged with parallel grooves (31) which abut against one another with their free outer surfaces, and in the section(s) through which the exhaust air flows later (3, 3b) the profile plates are arranged with crosswise grooves, i.e. with their free outer surfaces forming an angle to the free outer surfaces of the grooves (31) of the respective adjacent plate (40, 41). 4. Exhaust air scrubber according to claim 2 or 3, characterized in that the profile plates (30, 40; 41) used in the different sections (2a, 2b; 3a, 3b) have different have a channel cross-section which gradually becomes smaller from the sections through which the exhaust air flows first to the sections through which the exhaust air flows later. 5. Exhaust air scrubber according to one of claims 2 to 4, characterized in that at least some of the profile plates (40, 41) have grooves (31) which run in a zigzag pattern from top to bottom across the plate. 6. Exhaust air scrubber according to one of claims 2 to 5, characterized in that the channels (31) have wavy side walls (Fig. 7). 7. Exhaust air washer according to claim 6, characterized in that the waviness in the section(s) through which the exhaust air flows first is higher than in the section(s) through which the exhaust air flows later. 8. Exhaust air scrubber according to claim 6 or 7, characterized in that the walls of the channels (31) of the profile plates are wavy on their sloping upper sides and smooth on their sloping lower sides (Fig. 7c). 9. Exhaust air scrubber according to one of claims 1 to 8, characterized in that the individual sections or groups of adjacent sections form respective cleaning chambers. 10. Exhaust air scrubber according to one of claims 1 to 9, characterized in that the sections (2, 3; 2a, 2b, 3a, 3b) are arranged one above the other and the exhaust air can flow through them from bottom to top. 11. Exhaust air scrubber according to claim 10, which refers back to claim 9, characterized in that additional water outlet nozzles are arranged between the chambers.