DE2847145A1 - Clarifying, storing and transporting mineral sludge - esp. active cement sludge, via container fitted with stirrer and eccentric worm pump - Google Patents

Abstract

The plant consists of a sludge storage container with a conical base possessing a cone angle of 20-35 degrees. Stirrer blades with an inverted "V" cross-section rotate just above the base and are fixed on a tubular shaft which can be driven clockwise or anticlockwise by a motor located on the roof of the container. On the axis of the tubular shaft is an eccentric worm pump with its suction inlet 10-15 cm above the lowest point of the base of the container. The pump is also located on the roof of the container; and the pump and stirrer are driven according to a programme which includes self cleaning of the pump. The tubular stirrer shaft pref. has holes over 90-95% of its area at its bottom end, reducing to 50% at its upper end.

Description

Device for clarifying, storing and conveying away

of mineral sludge, especially active cement sludge Die The present invention relates to a device to active, cementitious Sludge from residual concrete washing systems in ready-mixed concrete and precast plants for To bring settling, to prevent it from setting and then out of the storage container The device and the method can also be used for other branches of production can be used wherever storage and transport of adhesive-containing substances are involved and those that due to very different grain densities for sedimentation and lead to caking.

Residual concrete processing plants and devices as well as processes to To be able to store and further convey the sludge phase of the residual concrete are for two reasons difficult: 1. because the cement paste, which can only be separated from the grain with water can settle on all surfaces, even vertical surfaces and in pipes and forms cement stones without moving, so that all are in contact with this cement paste coming machine components become inoperable after a short time.

2. Because residual concrete processing plants and thus the inventive Device not production facilities, but from the environmental protection agency imposed on the individual companies, mainly cost-increasing companies Represent additional equipment and the price level for such, non-productive Facilities, is inconvenient.

Tests have shown that cement paste in connection with sands of the Magnitude 0.1-0.5 mm under hydrostatic pressure of 2-5 m WS and below Water reaches such a strength within a few hours that suction becomes impossible with sludge pumps and only under the action of force by coarse equipment, like excavator shovels, cleaning of the sedimentation pits is possible.

It is already cheaper if the sands 0.1-0.5 are missing. Then the sludge mass dissolved in the water due to reduced hydrostatic pressure lower ~ 9 of the individual components can be moved longer, but then the movement factor plays a role, so the flow velocity opportunities within a storage container, a major role. If the flow velocities are too high, the lightest phase becomes discharged with the overflow water that is unavoidable under certain operating conditions, to be deposited elsewhere, which must also be avoided.

Also with regard to the removal of sludge, for example by a pump, the missing grain fraction 0.1-0.5 mm is reduced to 10-50 times Significant wear and tear.

The average amount of sludge 0 - 0.1 mm in one Ready-mixed concrete plant corresponds to approx. 0.5 - 2 7o of the production volume, or approx. 0.5 up to 2 m cement slurry per working day. The sludge accumulation is in precast factories about 0.2 - 1 m / day.

So far, various methods have been tried to remove these difficult slurries to store, transport or even use again.

Carry the scraper chain solutions within a clarification and settling trough the sludge from in a collecting tank; the mud is then already so dry that the pump can no longer be removed. Other transport facilities require a lot of additional construction effort and have not proven themselves, because the maximum grain limit cannot be fixed at approx. 0.1 mm and with the residual cement paste content leads to caking.

Sludge settling and clarifying silos, e.g. according to DBGM 74 30 539, 76 26 193, 76 36 577, 77 07 339, are used, but not reliable enough. at The silo is often unusable after a break with subsequent caking of the stored mass. Emptying with mechanical means is hardly possible compared to an underfloor basin possible.

Should the sludge be processed again, as it is in the concrete The lowest strength classes are possible, then a quantity dosing of the sludge is necessary from the storage container required. With centrifugal pumps this requirement is not to meet. Compressed air and diaphragm pumps or piston pumps run out after a few hours inoperative because the required ball valves are caked.

A compressed air delivery device has already been used with success.

A measuring container is required for this, into which the sludge is placed is pushed through a flap via a screw conveyor system. After closing the flap and pressurizing the container with compressed air up to 10 bar, the container is emptied via a delivery line. Must be inside the measuring container a scraper device in the form of a screw scraping on the walls available be. The dosing of the delivery rate is technically only at unreasonable expense possible.

Storage and conveying systems, such as those used in sewage and sewage technology are known, here is the state of the art, documented in OS 26 59 715, OS 26 48 545, OS 26 43 238, OS 26 31 945, PS 23 43 182, AS 19 57 685, PS 17 59 851, AS 15 17 967, OS 25 09 432, come to solve the problems mentioned out of the question.

The basic principle of the device according to the invention can be used with underfloor as in the case of overground landfills. It is shown as an underfloor solution, d. that is, the sludge collection tank is under the floor and the sludge flows from the separating cyclone in a downhill pipe.

Technical solutions to the requirements described in more reliable and cheaper execution are not known to this day.

First of all, it was necessary to find the cheapest form of storage container, in particular the container bottom in connection with simple stirring tools and a Tool carrier that largely prevents cement paste from sticking. Furthermore, the speed of rotation was to be set so that the Flow conditions interfere with the tendency to cake, on the other hand none on the surface too large flow movements occur, which may cause the cement paste over lead away the container overflow.

A conveyor system was also to be found that made it possible to remove the cement slurry safely out of the storage container even over longer distances of up to about 150 m to promote.

In addition, it was necessary to keep the sludge as uniform as possible Maintaining concentration so as not to work with a certain amount of sludge conveyed to promote strongly fluctuating water content, which has an increased W / C value Would adversely affect the strength of the concrete.

Finally, a self-cleaning system had to be developed prevents the entire conveyor system from deposits and caking becomes inoperable.

Comparative studies have shown that the most economical Way of storing the mud mass and keeping it moving, from an underground floor -Round or l 1 -basin with a depth between 2 and 3 m, with the bottom is conical, so that the lowest suction point is created in the center. at such a design is the ratio of the area to be covered by stirring tools to the total capacity as low as possible and thus also the required drive power small. The container is accessible from above.

Storage and drive are and are outside the water level Easily accessible in the hallway. The stirring tools consist of a few, simple components.

The container can be round or square in concrete easily and cheaply getting produced. Only the conical bottom is made of sheet steel.

A production of the container from steel is possible, but prepared Transport and seal two halves difficulties.

In the center, at the point of the sludge outlet, there is the slightest Flow velocity. By installing a swirler on the shaft extension the sludge pump is to create a certain turbulence here, if necessary.

According to the invention, the stirring tool carrier is designed as a tube inside of which the mud pump extends. The sludge pump preferably delivers in the agitator axis upwards.

The eccentric screw pump, known per se, is also used as the feed pump Outputs of 7-15 m / h selected, their simple, valveless conveying principle only 2 parts, the adjustable stator and the worm shaft exist (nd, on the The lowest point of the container and the gear motor located above the floor can be driven. Such a simple pump arrangement can be used quickly if necessary lifted out of the container. This pump enables precise dosing of the quantity.

There is an automatic flushing of the conveyor system with pure water with this pump principle possible in a simple manner in such a way that during the flushing process the pump is at a standstill, the rotor in the stator seals at the bottom, so that the water supplied the support tube with the drive shaft and pivot bearing washes around and over the delivery line escapes, flushing it free.

After this rinsing process, the water supply line is closed and the Pump switched in the opposite direction of delivery, so that the delivery line and the The interior of the support tube can be emptied downwards. This way is sufficient Frost protection achieved.

After the sand particles 2 0.1 mm separated out via a cyclone system are, the agitator can be stopped for a certain time without danger of not being able to start again. At sinking speeds of the fine materials from 1.5 to 4 m / h of particle size 50 ft or 0.1 to 0.3 m / h for particle size 10 without flocculants a downtime of between approx. 2 and 8 hours is required, with the addition of flocculants, this takes only 0.5 to 1 hour to ensure a good clarification of the water stored above the mud.

After this time, this, squeezed out of the mud, is and the water stored above the sludge is pumped out into a secondary clarifier. In order to the bandwidth of the sludge concentration is also narrowed to one concentration from 40-60 solids% in the total mass.

This pumping out process is automated according to the invention. So that will approx.

89 t of the total sludge residue from this agitator sedimentation tank to be taken.

The basin size corresponds to approx. 1.5 times the value for washing all Devices and cyclone operation required daily amount of water.

For vibration washing systems with cyclone fine separation there is a useful volume of the sludge collecting tank of approx. 40 - 45 m are found to be favorable. After replenishment of the pumped-out buffer volume through the evening washes is now water with Very fine substances are transferred to the downstream clarification or pure water basin. Essential the amount transferred is related to the overflow velocity.

According to the invention it is provided that the overflow velocity ontsprcchcnd by artificial extension of the weir width to 3-4 times the width to reduce.

Sludge removal is usually carried out in containers for sludge removal in the stockpile or in the mixer of the mixing plant.

Conveying distances of up to approx. 20 - 30 m are problem-free, for larger distances the lead time and delivery time is usually greater than the pure mixing time, so that perfect mixing of the sludge into the concrete cannot be expected. The solution according to the invention provides a circulation system for conveyor lines over 30 m before. This circulation system enables the sludge to be continuously available through the mixer to have and to be able to add quickly in doses. It is important in this context the formation of the distribution device. Nothing is allowed to settle here.

If the conveyor is not used for more than 30 - 60 minutes, an automatic flushing of the delivery rate takes place.

The apparatus and method according to the invention work with this difficult storage and conveying goods only maintenance-free with automatic operation, This means that all drives and functions are controlled via a program switching device or time control device, especially with regard to pumping out the water and Rinsing of the sludge pump and delivery line.

In the accompanying drawings, an embodiment of the invention is Device shown.

1 and 2 show the sludge settling and agitator tank with agitator, sludge pump installation in vertical section and in plan view.

Fig. 3 Position and cross section of a stirring tool above the bottom cone 4 shows the design of the sludge pump with flushing device FIGS. 5, 6, 7 sludge removal solutions 8 shows a possible design of the flow divider above the mixer Fig. 9 and 10 the schematic of the electrical sequence control, FIGS. 11 and 12 schematically so-called buffer / pumping operation Fig. 13, 14, 15 schematically the mode of operation: conveying, Flushing the pipe and flushing the pump Fig. 16 and 17 The design of an overflow weir for reducing the over speed.

When the sludge is stored in Ibchsilo, the bottom of the container is formed Init the stirring tools, the conveying and flushing equipment, as well as the electrical ones Control of agitator, sludge pump, rinsing device applied in the same way.

At Fig. 1 and 2, the sludge storage container is concreted and with a conical bottom 2 provided. The angular ones move just above the ground Agitator tools 3, which are welded to the agitator support 4 and by means of supports 5 against these are supported. The agitator support is flat from bottom to top decreasing passage openings through which a mass exchange between Agitator support interior 8 and container volume 9 is possible. With 7 are the openings marked in the agitator support between the angular agitator tools 3, through which the sludge passes through the agitator tools 3 in conjunction with the inclined Floor 2 is moved into the pump suction area. The agitator support 4 is connected above via a slewing ring 10 with the support structure 11 and in the The internal gear rim engages the drive pinion 12 of a geared motor 13. Other Drive elements are possible to use. The direction of rotation of the agitator is periodic left / right with pauses. This is where the material deposited on the stirring tools becomes rinsed off and a vertical movement is created in the mud mass. The supporting structure consists of the hollow profiles 15 with cross connection 16 and support profiles 17 and it is anchored in the sludge storage container 1. Between the hollow profiles 15 is a closed bottom 18 installed. Through several cover flaps 19, the area covered between the supporting structure and the pool edges, with the parts for Are foldable in the middle of the supporting structure.

Fig. 3 shows a stirring tool 3 in section. The leg ends 14 are ground so that no wedge effect but a z. B. plow-like digging The cutting edge opposite the base plate 2 is created.

The pump set is supported by resting it on a base plate 36 and higher lying on an engine console transverse reinforcement 37.

It is possible, however, to lock the unit on the bottom of the tank the inlet to the pump is obstructed and the passage of a scraper plate is obstructed the suction opening is no longer available.

A swirler 38 can be plugged onto the shaft end of the rotor.

An emergency hand turning device in the form of a hand crank 39 is on the The motor shaft stub on the fan side can be plugged on.

After loosening the quick coupling 28 and the fastening screws 40 and by turning the unit can be lifted upwards.

5 shows how it is possible to put the sludge in a container 43 to be filled with a special overflow edge, with the overflowing water back in the sedimentation tank is returned.

Since the power of the pump is relatively small, so is that Overflow speed over the approx. 10 m long overflow edge. It means that only a few lightest pieces of sludge flow out. It is estimated that about 95 7o Set down in the container. Such emptying of an agitator settling tank is cheaper than a previous excavator emptying and the degree of pollution is many times less.

6 shows the conveyance in a mixing device 44 of a mixing plant The distance can be horizontally up to approx. 30 m, vertically up to approx. 8 m. After the delivery line after each delivery process by reversing the direction of rotation of the pump is emptied, the dosing time is made up of the progress time and the delivery time for a designated amount together. If this dosing time is 2 of the mixing time, then an attempt must be made to increase the delivery rate of the pump or the delivery distance to reduce. The back suction always results in the next conveying process same initial values, which is very important with regard to the effective delivery rates is.

If the distance between the pump and the delivery point is greater than approx. 40 m horizontally, then the so-called circulation mode comes into question, FIGS. 7 and 8.

The pump runs z. B. from 7:00 a.m. constantly. Will not be mud dosed into a mixture, it flows back into the basin. Only when mud is supplied to the mixture, the flap valve 45 closes in the return line 46 and opens that 47 to the mixer. Both valves can have a common Drive can be operated. Instead of 2 separate standard valves, a watertight Reversible flap are provided. A reversible flap has the advantage that only small Dirt corners arise, while throttle valves create a small sack forms in which sludge can deposit.

The delivery line is only emptied before pauses in delivery # 1 H.

or after work.

Fig. 9 is a timing diagram for the sludge agitator.

As can be seen, the agitator runs for an adjustable time on the left and after another adjustable pause on the right, continuously, day and night and also over the weekend.

Idle times and breaks depend on the amount of mud to be filled and after 1, Xlge of the separating cut of the cyclone plant in front of the sludge settling and agitating tank.

I) itse T3etriel) s conditions apply to so-called pumping operations according to Fig. 12. This pumping operation is not possible, for example because an existing one is too small Basin volume is used, then during so-called continuous operation the agitator must be switched off completely in the evening during the wash-out operation. So is the turbulence in the basin is reduced and there is less cement paste in the secondary clarification or pure water basin transferred.

A timing program for the sludge feed pump is shown in FIG. 10 Flushing shown. If there is a longer pause in delivery than approx. 1 hour, then the pipe system and the pump are automatically flushed and the delivery pipe is sucked empty. This guarantees that the conveyor system will be used the next time it is put into operation functions. The automatic or manual flushing also takes place every evening afterwards End of work, for example with the cleaning run of the concrete mixer.

A variant for flushing the conveyor can be designed in this way be that the impulse for flushing is not automatically dependent on a timer comes from the last conveying process, but initiated manually by the mixer driver will. The mixer driver knows when no sludge has been added over a longer period of time and gives a manual flushing impulse after the last delivery.

In contrast to the so-called continuous operation FIG. 11, in which in each case the same amount of water Q 2 discharged from an agitator sedimentation and clarification basin which is supplied per unit of time, Q 11, Fig. 12 shows the so-called pumping operation, which is only possible if the container size is about 1.2 - 1.5 times larger than that daily rinse water volume.

If the sludge particles have settled in this case, then will the pre-clarified water is pumped out, preferably with a height-adjustable pump 48 low power, then about 40 - 60 a «O remains in the amount of sludge Q 3 Waser, that is, the W / C value of the concrete to which a small amount of sludge of 0.25 - 0.5% by weight is added, is only negligibly falsified, so that the Strength results still remain within the permissible tolerance limits.

SchRießlicl1 is in Fig. 13, 14, 15 the pump delivery principle with the Flushing device and the seal flushing shown more clearly.

13 shows the conveying position. The delivery pressure builds up in the support tube 21 on, which must be kept away from the bearing 23 via the mechanical seal 24. The flushing valve 29 must also close against this delivery pressure. Only with the appropriate Training these positions, sufficient operational safety can be achieved. It turned out to be for this cement slurry plant flap valves only (Steel flap in rubber housing ring) and hose pinch valves proven. When switched on The pump delivers sludge water through the discharge line 26/30.

14 shows the flow of water during the flushing process, flushing valve 29 is open. The pump support tube 21 with cardan shaft 51 and delivery line 2o / 30 is flushed free.

15 shows back suction and self-cleaning of the pump head. Valve 29 is closed. The pump rotor and the delivery line run in the opposite direction of rotation 30/26 as well as the pump support tube 21 are sucked empty, thereby stator and rotor cleaned by the pump.

An example of an artificially extended overflow weir is shown in Fig. 16 and 17 shown It consists of a vertical sheet metal with a recess 53 for a continuous soft rubber seal 54 and a lower bend 55 Sheet metal part 52 which is fastened with screws 56 in anchor dowels 57 of a partition 58 is.

Acute-angled strips 59 and the area are placed on the end face 60 under the ledges is closed. The water flows on the side of the higher one Water level in and over the edges of the strips 59.

It is important that the overflow layer thickness over all overflow points is equal to. In order to achieve this, the bar is provided with elongated holes 61. By the claw effect and lower or higher rubber pre-tensioning are the overflow edges to be adjusted exactly.

The individual devices shown, viewed separately, are for Partly known, but without the context according to the invention, the satisfactory one Solution of the problem not available.

Claims (13)

Claims 1) Device for clarifying, storing and conveying away mineral sludge, in particular active cement sludge, consisting of a Sludge storage tank with agitator running in this and a conveyor to remove a part of the amount of loops, marked with it «i (* hnet. the sludge collection filter (1) with a conical bottom (2) one Slope angle of 20-350 is provided, over which several roof-shaped stirring tools (3) move, which are attached to an agitator support (4), the direction of rotation of which is reversible Drive (B) on a supporting structure 15-17 over the hallway spanning the pool lies, with an eccentric screw pump 20-25 in the center of the supporting structure extends, the suction opening about 10-15 cm above the lowest point of the conical Bottom basin (2) is and which is also held on the support structure 15-17 is, with agitator run and sludge removal including self-cleaning of the conveyor takes place according to a set program, 2) device for clarifying, storing and conveying away of mineral sludge, in particular active cement sludge, according to claim 1, characterized in that the support structure of the agitator (4) consists of a tube consists of openings in the lower area of 90-95 area percent in the upper area Area evenly decreasing to approx. 50 area percent, with between those on the pipe A free passage is welded on and supported against this agitator blade (3) of at least 30 cm in length and 25 cm in height and the supporting structure attached to the supporting structure (11) in a rotatable manner at the top via a slewing ring (10) is, the drive by a preferably continuously adjustable in the range 1: 2 Gear motor takes place. 3) Device for clarifying, storing and conveying away minerals Sludge, in particular active cement sludge, according to claim 1, characterized in that that an eccentric screw pump consisting of stator (20) with rotor, support tube (21), Drive (25) outside the water level, supply line (27) for rinsing water and Discharge line (26) passed through the slewing ring and on the supporting structure 15-17 can be fastened, the discharge line (26) directly at the lower end of the support tube adjoins with an exit cross-section of at least 50 mm wide and 150 mm long, the conveyor pipe parallel to the support pipe up to about the height of the upper edge of the coupling housing runs and at this height the further discharge line (30) and the pure water supply line (27) can be prevented with a quick coupling. 4) Device for clarifying, storing and conveying away minerals Sludge, in particular active cement sludge, according to claim 1, characterized in that that the agitator periodically rotates left / right according to the program and that with the conical Container bottom (2) connected stirring tools (3) made of isosceles Angle profiles with a side length of 100 to 180 mm exist, which are spread over Support profiles (17) supported against the agitator support (4) and their lower leg edges (14) are worked into cutting edges, so that by the flow conditions the sludge water is moved vertically and caking on the agitator blades is avoided will. 5) Device for clarifying, storing and conveying away mineral Sludge, in particular active cement sludge, according to claim 1, characterized in that that the sludge water supply on 1 side of the container (l) via an opposite the Wall provided with a gap baffle (41) takes place, with a bulkhead wall (42), the extends over about 2/3 of the depth of the pool, the water flow takes over down and the outflow speed is approx. 4 - 10 times greater than the upflow speed in the container. 6) Device for clarifying, storing and conveying away minerals Sludge, in particular active cement sludge, according to claim 1, characterized in that that the supporting structure consists of 2 hollow profiles connected to one another in a torsion-resistant manner exist, which rest on the container edge (1) and can be fastened thereon and hollow profiles can also be supported on the inner wall of the container with additional profiles (17), that the space between the hollow profiles (18) is closed and the surface between The box girder and the container wall are also closed by a number of lids (19) is, the pivot point is at the box girders. 7) Device for clarifying, storing and conveying away mineral Sludge, in particular active cement sludge, according to the preceding claims, characterized in that the sludge is conveyed over greater distances in circulation with flow divider takes place in such a way that the delivery flow by means of a tight 2-way valve or two flap valves (45/47) either in a mixer or in the return pipe is performed, whereby in the latter case the distance between fork point and sealing surface (A) is less than 50 mm, the throttle valves can be electrically or mechanically interlocked are, so that when one outlet side is fully open, the other is tightly closed is. 8) Device for clarifying, storing and conveying away minerals Sludge, in particular active cement sludge, according to Claim 7, characterized in that that when fed into a mixing device (44), the switch-on pulse of the mixing system control for example "mixed water on" is taken and the flow rate is set by means of a timer, and that at least for conveyor distances over 20 m, if there is no circulating operation, or after pauses in delivery k 30 minutes after each delivery by reversing the direction of rotation of the pump the delivery line (30/26), the support tube (21) and the pump (20) are emptied. 9) Device for clarifying, storing and conveying away mineral Sludge, in particular active cement sludge, according to the preceding claims, characterized in that the flushing water supply line (27) seals against the pump delivery pressure opens in the upper area of the support tube (21) and the automatic flushing of Delivery line (26/30) and pump (20) over a time that can be set on the daytime clock and after a break in operation of longer than approx. 1 hour, whereby the flushing of the delivery pipe (26/30) when the pump (20) is at a standstill, and the flushing of the delivery pipe with pump by running the pump backwards according to the timer controlled, takes place. 10) Device for clarifying, storing and conveying away mineral Sludge, in particular active cement sludge, according to the preceding claims, in particular claim 9, characterized in that as a shut-off valve (29) for the flushing water supply line (27) a throttle or hose pinch valve to the Use comes. 11) Device for clarifying, storing and conveying away minerals Sludge, in particular active cement sludge, according to the preceding claims, characterized in that the flushing line (31) to the upper mechanical seal (24) removed from the throttle valve (29) and fitted with a slide (32) and with a pressure gauge (33), preferably a remote display pressure gauge, for control the function of the bearing flush. 12) Device for clarifying, storing and conveying away minerals Sludge, in particular active cement sludge, according to claim 1, characterized in that that the water squeezed out of the mud within a certain time by means of height-adjustable pump (48) is automatically pumped out, so that a buffer volume is released that is about 1.2 to 1.5 times the amount required or added daily Amount of water. 13) Device for clarifying, storing and conveying away mineral Sludge, in particular active cement sludge, characterized in that the overflow weir from the agitator settling tank to the downstream clarifier or pure water tank enlarged by a weir edge artificially extended to approx. 4 times the basin width will. l4) Device for clarifying, storing and conveying away mineral Sludge, in particular active cement sludge, according to claim 13, characterized in that that the overflow weir is made of a claw-shaped sheet metal part (52) with a seal (54? in the form of a soft rubber profile and numerous finger-like baffles (59) with bottom closure (60), the inclination setting by changing the rubber bracing is carried out by means of fastening screws (56).