GB2339425A

GB2339425A - De-watering apparatus

Info

Publication number: GB2339425A
Application number: GB9814974A
Authority: GB
Inventors: Colin Paul French
Original assignee: CLEARMASTERS ENVIRONMENTAL LIM
Current assignee: CLEARMASTERS ENVIRONMENTAL LIM
Priority date: 1998-07-11
Filing date: 1998-07-11
Publication date: 2000-01-26
Also published as: GB9814974D0

Description

2339425 CLEARMASTERS ENVIRONMENTAL LIMITED PATENT APPLICATION: MOBILE

PE-WATERING UNIT This inv"ionieLtesio 1hede-watedag ofAargepde zotioidssuch as waste concrete -slurryto leave a semi dry cake in the unit and a return of clean water to the customer. - In he conprete. ind, istry in particular, thp -is a I)mhlp-mjn disposin lo lancifil the-sluny-createdft= the cleaning of machinery and hopper lorries at the end of each days production. Although concrete sites attempt to dry the slurry by lifting it from the holding tanks and leaving it the drain in bunkers, relying on evaporation to dry the cake, this is time consuming and in wet weather the holding tanks over flow before the first batch has dried and been taken away.

This invention involves pumpin _g g the sluref into a first tank where it is a itated to break up any consolidated pieces of the slurry. It is then pumped into a second tank through large bore pipes. As it passes from one tank to the next, a. polymer is injected into it to ionise the particles so that they adhere together, forcing out the water content. When the solution reaches the second tank the process has started to work and the coagulatedparticles as theyaet bigger sink downwards through the solution to be captured by internal screens in the tank. The water. is forced out through the screens and drains back to the holding tank as clean water.

The essential features of this invention are two mobile tanks (one of which could be a vacuum tank), a pump with a control valye that can load the first tank from the site holdirig tank and then transfer it to the second pump,,a second pump -which can mix-and inject-the -polymer solution into the pipework between the first tank and the second tank and a screening system in the second tank to filter out the particles as they co a laulat an -settle. The second-taak-aiso-requkes drainin a(alv-pas and pipewDrk -to xztum the clean water to the holding tank.

A specific embodiment of the process will now be described by way of schematic examples as attached. As the process could be carried out either by a chassis mounted tank divided in half with the requisite machinery orby towing the settling tank behind a tankerlorTy, theprocess will described under both options.

MOBILE CHASSIS MOUNTED TANK DIVIDED INTO TWO TANKS -OPN I - STAGE 1 - The concrete slurry ispumped into Tank I usin _g cam pump 2 to ensure the g a rotatin concrete slurry does not contain any large pieces. Once in Tank I an impeller device driven by a hydraulic motor 3 is rotated at high speed to further mix the slurry.

STAGE 2 - The slurry is then pumped into the second Tank 4 - the settling tank. As it passes through to this tank, it is injected with an ionisin-g- pojymer 5. By the time it reaches the second tank, the reaction has started and particles are coagulating ready to be filtered out of the water by the screens 6.

STAGE -3 - Water is being squeezed out the slurTy, leavirig a residue behind the internal screens 6 with the second tank and clear water passes out through drain valves 7 at the base of the tank.

TOWED UNIT DRAWN BY A VACUUM TANKER LORRY - A" 2 - LPA-cL!) STAGE 1 Concrete slurry is drawn into the vacuum tank 1 by the displacement pump. The slurry then has high pressure compressed air 2 blown through it to break up any large lumps and ensure the slurry is fully mixed.

STAGE 2 - The slurry is then pumped to the towed settling tank. As it passes through to this tank, it is injected.,3 mdtb-an innis! g polymer- By lbe lime it machas 1he secon laak 4, the seaction has started and particles are coagulating ready to be filtered out of the water by the screens 5.

STAGE A - Wate s_be squeezed-oLd-the-slurly, lpnyin a CeSirb i hehia the latemal-screens 5 with the second tank and clear water passes out through drain valves 6 at the base of the tank.

Claims

1. The Mobile De-watering Unit uses a chemical reaction to coagulate the large particles of concrete slurry thereby squeezing out the water content allowing it to drain back into holding tanks for reuse.

2. As claimed in Claim 1. the reaction will coagulate the slurry to form a semi dry cake which can be left which is easier to transport to landfill or recycling depot.

3. As claimed in Claim 1, the chemical reaction is started whilst it is beinapassed from the mixing tank to the settling tank by injecting the polymer into the pipe transfening the slurry from one tank to the other.

4. As claimed in Claim 1, screens are placed in the settling tank to hold back the coagulated solution allowing tate-to-pass through lolbe x1rain maJves-at-the -base -of Abe 1,'Wk.

5. As claimed in Claim 1, in either version of operation (Option 1 or Option 2) the essential feature is that the concpete-qua:y must be thoraLQhty mixe _wnnolargelumps Thisisachip edeW:texby-animpeJ1er device or by high pressure compressed air.

6. A Mobile De-watering unit as claimed in Claim I as herein described with reference to diagrams notated as Option I and Option 2.

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