HK64396A

HK64396A - Dehydration process of aqueous suspensions, and screw press therefor

Info

Publication number: HK64396A
Application number: HK64396A
Authority: HK
Inventors: Eichler Dietrich
Original assignee: Gebr. Tigges Gmbh & Co. Kg
Priority date: 1988-11-03
Filing date: 1996-04-11
Publication date: 1996-04-19
Also published as: JPH02258196A; JPH07110436B2; EP0367037B1; EP0367037A2; EP0367037A3; DE58906496D1

Abstract

In a process for separating and dehydrating solids which are present in waste water, in particular from intensive animal husbandry or industrial processes in which plants or animals or parts thereof are processed, in a low concentration of less than approximately 10% and are interspersed with fibres, such as for example animal hair or vegetable fibres, in which the waste water is introduced into a screw press, the solid present therein is formed there into a slug by the interaction of a screw press, which is driven by a drive motor and reaches into a strainer basket, and is pressed out of the screw press dehydrated as a slug, while the water freed from the solid is drained from the housing of the screw press, the waste water is, in order to achieve trouble-free operation irrespective of the various types of liquid manure and variations in consistency, and to increase the range of applications and the flexibility of the screw presses, increase the dry substance content in the solid and to change the form and the shape of the solid slug, introduced into the screw press and a solid slug is produced in the latter, which, when pushed out provides, in itself and braced against the wall, parallel to the conveying direction, of the strainer basket and a cylindrical projection extending the latter, the opposing force necessary for the dehydration; for this purpose it is proposed that the screw press (20) has at least one screw spiral (27) of constant pitch, which begins upstream of the inlet end of the strainer basket (13) and reaches at least to the centre thereof, the spiral edge (27.1) being guided until close to the inside of the strainer basket (13) and the remaining length, free from the screw spiral, of the strainer basket (13) being at least equal to its diameter, and that the separator housing (10) has a cylindrical mouthpiece (15) whose internal diameter is equal to the internal diameter of the strainer basket (13), and that the solid slug is enclosed to the extent of approximately 70 to 95% by the spiral-free part of the strainer basket (13) and to the extent of approximately 30 to 5% by the cylindrical mouthpiece (15). <IMAGE>

Description

The invention relates to a process and device for the separation of waste water and solids from solids containing waste water, whereby the waste water is introduced into a screw separator, the solids contained therein being formed into a plug by a screw driven by a drive motor, reaching into a sieve, and drained as a plug from the mouth of the screw separator, while the water released from the solids is drained from the housing of the screw separator.

In a known process and a known device of the type mentioned at the outset (DE-A-34 28 381), both the screw-driven screw and the screw-driven screw end at a considerable distance from the mouth of the housing. The known device is used to compress and drain solids, not to drain solids suspended in water. In the known device, the solid is carried through the screw-driven screw only over part of the screw-driven housing and then moved to a screw-free zone where the solid is further drained. Finally, the solid drained is to be discharged from the exit opening of the screw-driven screw.

This solution is not suitable for the dewatering of solids suspended in water, since the solid graft is softened and washed off from the centre axis.

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The simple machines for separating solids from liquids are the screw press or the screw separator. The principle is often to gradually compress the separated solid from the screw windings which become narrower for the purpose of extrusion. The pressure buildup by means of constriction is also described in German patent 26 36 372 and in German patent notice 29 11 899. However, the practical operation of these devices shows that all conically rejuvenating areas are proportional to the throughput, the range of application and the flexibility of the screw separator.

In the case of the separator shown in German patent No 27 00 542 and 29 02 432, conical parts were already omitted, except in Figure 2 where the passage through the wall 14 to the screen diameter 24B is shown to be smaller, so that this wall piece could build up a counterpressure.

The purpose of the invention is to increase the range of application and flexibility of the press-slug separators described in the patent applications and to increase the dry matter content of the solid by modifying the formation and form of the solid grafting to achieve smooth operation of the machine regardless of the different types of slurry and variations in consistency.

The solution to the technical problem of clotting, transport and excretion of the solid is that the solid cake is in the sieve in all areas of drainage and the clamping separator is so designed that no solid can accumulate between conical or rejuvenating parts.

In particular, the solution to the problem is achieved by building up the necessary back pressure by internal tension of the elastic solid under pressure by friction on the walls bordering the sieve parallel to the conveyor direction. The sieve starts to form before the sieve, with pressure rising from the outlet of the screw-screw to the end of the sieve, before falling to the mouth. This pressure rise in the part of the sieve which is free of the screw-screw is essential for further drainage of the solid retained on the sieve surface.The solid fuel injectors themselves are carried and discharged in a cylindrical sieve box made of axis-arranged sieve rods with 0,5 to 1,5 mm gaps, and are transported by a cylindrical piece of material attached to the sieve box and the cylindrical mouthpiece, which extends beyond the mouthpiece, carried and discharged by a cylindrical snail shaft as a high-cylinder body.In dry suspensions, dehydrated solids can be used to improve the formation of the filter cake.

The forces generated by the pressure in the elastic plug compress the cylindrical sieve between the walls of the sieve, the mouthpiece and the elongated screw nozzle to such an extent that the waste water cannot penetrate or even push out the solid plug.

To prevent water from being forced out and thus the plunger from being destroyed, the device is designed so that the hollow cylindrical solid plunger is surrounded by the sieve cylinder 70-95% of its length. The water that is drawn out can escape through the slot of the sieve basket without compromising the stability of the solid plunger.

The slurry used to form the solid graft has a steady slope from the inlet to the start of the graft, consisting of turns perpendicular to the axis, thus avoiding entanglement and congestion of the separated solid in the slurry twisting area.

The stability of the graft is largely dependent on its homogeneity in addition to its internal stresses. To achieve a mixing effect in the formation of the graft, the last of the snail turns was laid out before the grafting of the solids, running outwards to the snail core at about 180-360°. This additionally achieves increased compression in the area of the snail core.

At the same time, the outward projection of the screw produces an even distribution of axial and radial forces, enabling the screw-soul and the solid plug to act as the projection bearing.

Since no plug is in the machine when the press separator starts working, an auxiliary plug, such as a foam (styropor) plug, is inserted from the extrusion side before the engines of the waste water pump and the separator are started and is clamped so that it is only pushed out of the press separator under the pressure of the solid moving forward.

On the side of the separator, the screw is made to twist 2-3 times in a tube, so that the existing surface is fully loaded with the already concentrated but still circulating suspension.

The waste water is normally supplied to the filtered filter by a circulator pump, and this is advantageous in the excess. To recycle the excess, a back-up plunger is placed immediately next to the feed. The filtered spirals, placed between the inlet and the filtered filter in the inlet, limit the area of overflow and thus prevent the discharge of solid particles enriched in the wall area, which are supplied to the filtered filtered filter through the filtered filter. The feed is thus regulated independently by the filtered filtered filter.

In order to make the machine simple and robust, the screw core has been fitted with a plug to the drive storage; the screw hub is also held in place inside the screw separator by means of handles arranged in parallel on the outside of the screw hub, in conjunction with handles on the inside of the separation chamber housing, so that the screw hub can be moved into the housing's supports without any additional attachment.

On the outer side of the sieve, the ends of the sieve rods are inserted into a ringnut of the flange of the mouthpiece, providing support for the sieve rods and centering between the mouthpiece and the sieve.

For manual adjustment of the length of the mouthpiece acting on the dry matter content of the solid, a cylindrical, axially movable and clampable, thin-walled extension of the mouthpiece is pushed over the fixed mouthpiece, selected from a number of rings of different lengths.

To compensate for the fluctuating operation of the slurry separator due to differences in the consistency of the effluent, the rate of effluent outflow is regulated by an exhaust regulator located outside the mouthpiece at the bottom of the cylindrical mouthpiece at the solid outlet, capable of covering the exhaust area between 0% on one side and about 10% to 25% on the other side. A lever with the exhaust nozzle partially covering the surfaces on which a reservoir is placed is conveniently placed to do this. This reservoir is advantageously generated by a weight load, which is exerted by changing the weight and/or by changing the height of the exhaust. The solid is emitted after it has been released and the exhaust area is free to flow and the exhaust is emitted in the entire ring.

In the case of the possible automatic adjustment of the length of the mouthpiece acting on the dry matter content of the solid, the thin-walled cylinder is moved by a drive using the current intake of the motor of the press-slug separator to control it.

If the plug becomes too soft due to a malfunction, there is a risk of rupture of the suspension on the solids side, which is indicated by a fall below a predetermined current intake value of the motor of the screw separator, so that the feeding pump and separator can be automatically switched off.

Figures 1 to 8 show an example of a press-slug separator according to the invention, showing the Figure 1:a longitudinal section of the screw separator without formed, transported and ejected plugs,Figure 2:section of the screw separator in the area of the waste water supply according to II-II (Figure 1),Figure 3:section of the screw separator in the area of the sieve according to III-III (Figure 1),Figure 4:section of the screw separator in the area of the cylindrical approach according to IV-IV (Figure 1),Figure 5:section of the sieve torsion control unit,Figure 6:section of the sieve - end-loading.Figure 7:section of the exhaust regulator,see Figure 7a:section closed,Figure 7A:section open;Figure 8 -section open;Figure 8 -section open;Figure 8 -section open;Figure 8 -section open;Figure 8 -section open;Figure 8 -section open;Figure 8 -section open;Figure 8 -section open;Figure 8 -section open;Figure 8 -section open;Figure 8 -section open;Figure 8 -section open;Figure 8 - open;Figure 8 - open;Figure 8 - open;Figure 8 - open;Figure 8 open;Figure 8 - open;Figure 8 open;Figure 8 open;Figure 8 open;Figure 8 open;Figure 8 open;Figure 8 open;Figure 8 open;Figure 8 open;Figure 8 open; 8 open; 8 open; 8 open; 8 open; 8 open; 8 open; 8 open; 8 open; 8 open; 8 open; 8 open; 8 open; 8 open; 8 open; 8 open; 8 open; 8 open; 8 open; open; open; open; open; open; open; open; open; open; open; open; open; open; open; open; open; open; open; open; open; open; open; open; open; open; open; open; open; open; open; open; open; open; open; open; open; open;

In Figure 1, the different phases of the transformation of the suspension into a liquid and a solid phase are shown by A to F. The letters represent the following phases: A:Inflow and overflow of the suspension,B:Admission control areaC:Circulating drainage areaD:Building pressure area with mixing and homogenisation effectE:Drawing area of solid graft,F:Solid drainage area.

The procedure is described in Figure 1 for manure separation as follows:

The excess manure is fed into the manure storage tank and a part of it is returned to the manure storage tank. This flow moves the manure in the storage tank and prevents the solids contained in the manure from settling. The manure pump, driven by the drive motor 24 through the gearbox 25, extends the absorption capacity of the press run of a corresponding proportion of the manure and thus regulates the manure storage tank 27 7 by the same means, first introducing the snow-filled solids into the solids in the storage tank, allowing the manure to form a solid shape in the unalloyed position of the wall of the manure storage room,the pressing pin 20 transports the solid-graft to the exhaust chamber 8, increasing the pressure until the end of the slurry shaft 27 in the slurry outlet 28, and with the pressing the drainage of the solid collected in the graft. This pin is carried to the exhaust nozzle 5 on the outside of the sieve pin 13 and the cylindrical mouthpiece extending the sieve pin 13 on the inside 15 and on the outside of the slurry shaft 21 and its exhaust nozzle,The pressure produced by the press is then applied to the outlet 5 and the plunger is finally pushed out. In practical operation, a plunger separator was used to separate solids from pig manure, which achieved a throughput of 4 m3/h at a dry matter content of 5.2% in the pig manure. This plunger separator had a 500 mm screen with a cylindrical passage of 260 mm screen and mouthpiece. The screen had a clearance of 0.75, the plunger had a screen with 5 passes, a total diameter of 100 mm, and a length of 400 mm. The plunger was made of propane with a length of 110 mm.The power required to operate the screw separator was reduced to 2.2 kW at a speed of 30 rpm. Under these operating conditions 220 kg/h of solids were separated with a dry matter content of 32%, the waste water with a discharge of 3.78 m3/h had a residual solids content of 3.7% relative to dry matter, which corresponds to a solids-related separation rate of 32.7%. The Styrene-porous auxiliary drums needed for the start-up had the corresponding hole diameter of 110 mm and the external diameter of 260 mm and a length of 300 mm.The overflow was about 1.5 m above the inlet and discharged many times the amount of the inflow through the waste water - return flow 3 as excess into the manure pit, with the relatively large amount being sufficient to homogenise the 10 to 20 m3 pump pit.

To simplify the construction of the screw separator 1, as shown in Figure 1, the screw 20 is connected to the motor 24 and gear 25 by a simple connection to the drive shaft 26 of the drive mounted on the drive side flange 11.1 of the screw separator housing 10. In addition, the output shaft 26, over which the hollow shaft 21 is mounted, is fitted with connectors 26.1 provided for in the respective exceptions at the drive end of the screw shaft 21.The sieve 13 itself is surrounded externally by a chamber mantle 12 which divides a ring chamber into which the water separated in the sieve collects for discharge by the water outlet 4. This chamber mantle 12 is connected to the inlet chamber 6 by its inlet flange 12.2 and to the cylindrical mouthpiece 15 by its inner ring 12.3. The pre-slurry 27 ends at the end of the sieve 13 and the slurry outlet 28 is formed. The solid material which is extracted by the condensation is transported backwards from the slurry outlet, to the mouthpiece 15.1.The pressure buildup leads to further drainage and to the deposition of the solids still being transported at the end of the screw. The final screw, which is carried out at 360° towards the screw's core, 28 mixes the solids before it is deposited at the screw, condenses them near the screw and creates a uniform axial and radial pressure. This allows the screw to take over the centering and storage of the screw 20 from the screw.1 of the nozzle 21 is pressed and enters through the mouthpiece 14 into the area of the exhaust nozzle 5 of the solid nozzle 5 to adapt the length of the plug to the situation, a sliding and adjustable extension 16 is placed on the tube of the cylindrical nozzle 15 and is fixed to the tube by the tension strip 16.1 by means of the screws 16.2 which are soluble.

Figures 2, 3 and 4 show cross-sections through the screw separator according to the II-II, III-III and IV-IV intersections shown in Figure 1. Figure 2 shows the cross-section of the inlet chamber 6 at the level of the supports for the inlet 2 and the back outlet 3 which join these chambers, with respect to the drive end flange 11.1.The screen bars are held by supporting rings 13.2 which can be fitted as rings or as winches. On the outside of these supporting rings 13.2 there are axis-parallel supporting bars 14 which, in exceptional cases, can intervene in the inside of the chamber housing 12.1 and absorb torsion moments and can be introduced into the housing. In the press-slot saver shown, the screen bar 13 is fitted with three axis-parallel, 120° positioned supporting bars 14 which are inserted into the supporting bearings 12.1 and 12.1.The inside of the sieve 13 is the screw shaft 21, which is fitted with the screw pin 27 here. Figure 4 shows the cut through the exhaust chamber 8 with respect to the screw flange 15. Screws 12.4 show the attachment of the screw flange 15 to the inner ring 12.3 (Fig. 6). The screw 15 is concentric to the separation chamber 12. In the lumen of the screw 15 is the screw shaft with its overhanging wave end 21.1, and the depth of the screw flange 27 is visible at the wave outlet 28.

Figures 5 and 6 show details of the attachment of the screen 13 in the partition area. The screen 13 formed by the axis-parallel screen bars 13.1 is surrounded by support rings 13.2 on the outer sides of which at least one support rod 14 is attached. Correspondingly, on the inner side of the screen chamber mantle there are 12 holding holes 12.1 with exceptions for the approximate form of the support rods. These exceptions are dissolved for each holder in a necessary way. The screen bars 13.1 are connected to their outer ends by a ring-shaped screen 15.2 in the mouthpiece 15.1 of the screen 15.1 and 15 centred on the mouthpiece 15.1 The backscrew is also attached to the mouthpiece 12.4 of the screen 12.5.

To compensate for the fluctuating operation of the screw press separator due to differences in the solids content of the waste water, the lower part of the exhaust nozzle 5 is switched on, where a cylindrical nozzle 17 is attached to a rotating element 17.3 as an exhaust regulator and connected to a lever 17.1 by means of which the load which can be adjusted with a displacement weight 17.1 can be transferred to the flake iron and the flags and thus to the exhaust regulator.

Claims

Method for separating waste water and solid matters for waste waters containing solid matters, wherein the waste water is fed into a screw press separator, the solid matter contained therein is formed into a plug by virtue of a worm which is driven by a driving motor and which worm extends into a perforated basket and the solid matter is pushed in the form of a dewatered plug out of the mouth of the screw press separator, whilst the water which has been extracted from the solid matter exits from the housing of the screw press separator, characterised in that the solid matter which is compacting by virtue of the pressing force of the screw press, is pressed out of the mouth through a hollow cylindrical annular gap between the worm shaft and the perforated basket.
Method according to claim 1 characterised in that the waste water is fed in excess from the waste water container by way of a delivery pump and the excess is returned as a run back into the storage container for the waste water to be purified and this waste water is agitated.
Method according to claim 1 or 2, characterised in that the pressure in the screw press separator is held at the pressure level of the ambient atmosphere by way of a pressure compensating line in the waste water container.
Method according to one of claims 1 to 3, characterised in that for the purpose of improving the formation of the plug, preferably in the case of waste waters with low solid matter contents, dewatered solid matter is returned to the input of the separator and added to the inlet.
Method according to one of claims 1 to 4, characterised in that the power drawn in by the driving motor is controlled and when the plug is not sufficiently dewatered and consequently when not achieving a minimum required power which presents the danger of the water containing the solid matter breaking through, the driving motor of the screw press is switched off.
A screw press separator for the purpose of carrying out the method in accordance with one of claims 1 to 5, having a housing (10) which comprises an inlet pipe (2) for the waste water, an outlet pipe for the separated water and a mouth for the dewatered solid matter, furthermore having a screw press (20) which is disposed in the housing (10) and which is driven by a driving motor (24) and furthermore a perforated basket (13) which is formed in a cylindrical manner encompassing the screw press (20) and is supported against the housing (10), wherein the screw press (20) encompasses a worm shaft (21), which is encompassed by a worm spiral (27) whose edge is guided as far as closely up to the inner side of the perforated basket, characterised in that the end of the worm shaft (21) protrudes beyond the mouth piece (15) and the diameter of the worm shaft is one-times to two-times the width of the annular gap of the worm shaft and the perforated basket (3).
A screw press separator according to claim 6, characterised in that the separator housing (10) comprises a cylindrical mouth piece (15) whose inner diameter is identical to the inner diameter of the perforated basket (13) and that the hollow cylindrical solid matter plug is enclosed up to approximately 70% to 95% by the spiral-free portion of the perforated basket (13) and up to 30% to 5% by the cylindrical mouth piece.
A screw press separator according to claims 6 or 7, characterised in that the worm spiral (27) which ends in the perforated basket (13) is formed in the region of its last thread (28) at least by 180° from the end of the worm spiral (27) onwards extending to the worm shaft (21).
A screw press separator according to one of claims 6 to 8, characterised in that the worm shaft (21) of the screw press (20) is connected to the driven shaft (26) of the driving motor (24) or of the gear (25) by means of a plug-in coupling (23) provided on the end at the driving side.
A screw press separator according to one of claims 6 to 9, characterised in that the perforated basket (13) is formed as a slotted hole screen whose sieve bars (13.1) extend axis parallel, wherein the width of the gap of the slotted hole screen amounts preferably to 0.5mm to 1.5mm.
A screw press separator according to one of claims 6 to 10, characterised in that the perforated basket (13) is provided with at least one, preferably three, holding rods/small rods (14) which are provided on the outer side of the perforated basket (13) and which holding rods/small rods absorb any torsional forces which occur and that holding projections (12.1) are provided on the inner side of the separating chamber periphery encompassing the separating chamber (7), these holding projections (12.1) are provided with aligned recesses and interact with the holding rods/small rods (14).
A screw press separator according to claim 11, characterised in that the cylindrical mouth piece (15) is releasably attached by means of a mouth piece flange (11.3) on an inner ring (12.2) which surrounds the separating chamber (7), wherein the inner ring (12.2) comprises recesses which correspond to the holding rods/small rods (14) and are aligned with the recesses of the holding projections (12.1) and preferably the free end(s) of the holding rod/rods (14) engage therein.
A screw press separator according to one of claims 6 to 12, characterised in that the cylindrical mouth piece (15) guided out of the housing (10) is provided at its protruding end with an extension piece (16) which can be pushed on and fixed and which allows the length of the plug to be adjusted, preferably equipped with an actuator for carrying out automatic adjustments and consequently for regulating the length of the plug.
A screw press separator according to one of claims 6 to 12, characterised in that a pivotable ejection controller (17) is provided outside the mouth (5) of the cylindrical mouth piece (15) or of the extension piece (16), in such a way that the area of the mouth (5) for the dewatered solid matter is partially covered, wherein the maximum covered partial area of the mouth amounts to 10% to 25% of its entire area, and wherein the ejection regulator preferably having a lever (17.1) which pivots about a pivot axis (17.3) is provided with the means of producing an adjustable counterforce, preferably in the form of an adjustable counterweight (17.2).