GB1568500A - Reclamation of waste residue of concrete - Google Patents

Description

(54) IMPROVEMENTS IN OR RELATING TO RECLAMATION OF WASTE RESIDUE OF CONCRETE (71) We, STOTHERT & PITT LI MITED, a British Company, whose registered address is, 166, Lower Bristol Road, Bath, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a waste concrete residue reclamation unit and to a method for reclaiming waste concrete residue.

More particularly, the invention is concerned with a method and means for reclaiming the waste residue concrete from a concrete mixer drum with special reference to a truck or transit mixer.

It is well known that, after truck mixers have discharged their load, variable amounts of concrete residue remain in the drum and this, during their return journey to base, tends to adhere to the drum.

Therefore, before re-charging the drum, it is necessary to clean it in order to avoid "contaminating" the next load.

The cleaning operation uses large quantities of water and creates problems regarding the disposal of the material, and of course of the contaminated water.

It is among the objects of the present invention to provide a method and means for reclaiming the waste material for re-use, and also for reclaiming or re-using the water used for washing out the drum.

According to the present invention, there is provided a method of reclaiming the residue of concrete in a concrete mixer drum, which comprises passing water from a water-filled settling tank into the drum, discharging the resultant slurry comprising the water and the residue, which residue includes aggregate, sand and cement from the drum into the tank, separating within the tank aggregate from the slurry, cleaning and discharging the separated aggregate, allowing the separated slurry to settle in the tank and finally discharging settled sludge comprising the sand and cement from the tank.

According to the invention furthermore, there is provided a unit for reclaiming the residue of concrete in a concrete mixer drum, which unit comprises a settling tank, a first structure provided at one end of the tank and having means for separating aggregate of the residue, means for cleaning separated aggregate, and means for discharging the separated aggregate, a second structure provided at the other end of the tank and having discharge means for settled sludge comprising sand and cement, a support plate to receive the residue from the mixer drum, the support plate being positioned in the tank and having a horizontally disposed portion and a portion extending upwardly into the first structure, an endless conveyor extending between the first and second structures, an upper run of the conveyor serving to transport the residue to the aggregate separating and cleaning means and a lower run of the conveyor serving to transport the settled sludge to the discharge means of the second structure, and water supply means, including a pump, for passing water from the tank to the mixer drum and for passing water from the tank to the aggregate separating and cleaning means.

The invention is diagrammatically illustrated by way of example in the accompanying drawings in which, Figure 1 is a side elevation of a waste concrete residue reclamation unit according to the invention, and Figure 2 is an end elevation on an enlarged scale, in the direction of the arrow "A" of Figure 1.

Referring to the drawings, a waste concrete residue reclamation unit comprises a settler tank 1 of rectangular cross-section having inclined ends 2 and 3. The tank 1 is made up of sheet metal panels and a supporting framework of horizontal and vertical frame members 4.

Supported on the inclined end 2 of the tank 1 is a waste separation and aggregate discharge structure 5 which houses a wastereceiving hopper 6. Positioned below the hopper 6 is an inclined screen 7 which depends from resilient supports 8, the screen 7 being subjected to vibratory movement by means of a suitable vibrator device 9. Adjacent the lowermost end of the vibratory screen 7 there is an inclined discharge chute 10 which, in use, serves to receive and discharge aggregate.

Supported on the inclined end 3 of the tank 1 is an inclined sand and cementcontaining sludge discharge structure 11.

Positioned within, and extending the full width of, the tank 1 is a support plate 12 having a horizontally disposed portion and a portion which extends upwardly into the structure 5 where it terminates, above the hopper 6, in a discharge end 13.

An endless conveyor 14 having an upper run 15 co-acting with the support plate 12 and a lower run 16 co-acting with the floor of the tank 1 is provided to effect movement of the waste deposited in the unit. The conveyor 14 comprises a pair of spaced drag chains 17 between which are disposed a plurality of spaced rubber tipped scraper bars 18. At the end 2 of the tank 1, the chains 17 pass round co-acting sprockets 19 mounted on a tailshaft 20 which is supported in bearings 21 positioned on the structure 5.

At the other end 3 of the tank 1, the chains 17 pass round sprockets 22 mounted on, and keyed to, a headshaft 23 which is supported in bearings 24 positioned on the structure 11.

Drive to the conveyor 14 is provided, via a gearbox 25, by a two-speed motor 26 which is supported on the structure 11. For this purpose, a drive sprocket 27 is provided on the output shaft of the gearbox 25 and drive is imparted to a driven sprocket 28 keyed to the head shaft 23 by means of a drive chain 29. In this respect, in order to compensate for any irregular pull in the two drag chains 17, one of the two sprockets 19 mounted on the tailshaft 20 is keyed to the tailshaft whereas the other sprocket 19 is freely mounted thereon.

In order to provide proper guidance for the conveyor 14 through the unit, arcuate guide shoes 30 are provided at selected positions where the drag chains change diriaa hl m the tank 1 of the unit is filled with water nj to a water level indicated at WL, an overfl6w outlet being provided at 31 and a efrainage outlet at 32. In this respect, as herei}iter described, the water in the tank is contintially re-cycled and cleaned. For this purpose, a water supply system is provided which comprises a submersed water pump 33 which is connected, via a feed pipe 34, to an inverted U-shaped supply pipe 35 which is fixed at its lower ends to one side of the tank 1. An outlet pipe 36, which is used to wash out a mixer drum, is connected to the central part of the supply pipe 35. Positioned in the supply pipe 35, above the connection of the feed pipe 34 thereto, is a multiway manually operated control valve 37. A spigot 38, to which is connected a T-junction 39, is connected to the valve 37.

One branch of the T-junction 39 has a spray bar 40 connected thereto which serves to spray jets of water downwardly, whilst another branch has a spray pipe 41 having jet nozzles 42 connected thereto to direct jets of water onto the lowermost end of the inclined screen 7.

A control panel 43 is positioned on one side of the tank 1 close ta the water control valve 37 and has a first push-button, a second push-button and an emergency stop button.

A control box 44 is mounted on the end 2 af the tank 1 and houses all the electrical controls for the unit which include four adjustable timer devices as follows:- Timer T1 - This controls the period of time during which the pump 33 is operating and is set to stop approximately one minute after the "timing out" of timer T2.

Timer T2 - This controls the period of time during which the conveyor 14 Is operating at a higher speed.

Timer T3 - This controls the period of time during which the pump is not operating and the conveyor is stationary - this period of time is provided to allow siIt to settle to the bottom of the tank 1.

Timer T4 - This controls the period of time during which the conveyor 14 is operating at a lower speed to remove the settled fine silt from the bottom of the tank 1.

In use, in order to clean the drum of a truck mixer and to recIaim the residue of concrete therein, the truck driver reverses the truck into a suitable position near the unit He then places the water outlet pipe 36 in the drum and turns the valve 37 into a position where water can flow to the pipe 36. The first push-button is then depressed to start the pump 33 and thereby feed water into the drum. When sufficient water has been fed into the drum, the first pushbutton is released.

The valve 37 is then turned to feed water to the spray bar 40 and the spray pipe 41.

The second push-button is then depressed and the contents, i.e. the water and concrete residue, of the drum are discharged onto the support plate 12. When the second pushbutton is depressed, the automatic sequence of operation of the unit commences. Thus, the conveyor starts to operate at the higher speed, the pump 33 delivers water to the spray bar 40 and the spray pipe 41, and tuners T1 and T2 are energised.

During this part of the operation, the waste, i.e. aqueous slurry containing aggregate, sand and cement, is propelled along the support plate 12 by the scraper bars 18 in the upper run 15 of the conveyor and is discharged at 13 into the hopper 6 from which it is deposited on the vibratory screen 7. The mesh size of the screen is such, for example, that the + 3/16" material (larger aggregate) is discharged over the screen into the chute 10 to a waste skip or other container for re-use, and the - 3/16" material (smaller aggregate, sand and cement slurry) passes through the screen into the water in the tank to settle on the tank bottom. It will be appreciated that the spray bar 40 serves to keep the scraper bars 18 free of deposits and also assists in separating the larger and smaller materials. Also, the nozzles 42 of spray pipe 41 serve effectively to clean the larger aggregate before it is discharged.

en timer T2 "times out", timer T3 is energised and the conveyor 14 ceases to operate. However, the spray bar and spray pipe continue for a further minute to cleanse the conveyor, the hopper 6 and screen 7.

The unit then remains inactive to allow the smaller material to settle.

When timer T3 reaches its pre-set time, the timer T4 is energised and the conveyor 14 is set in motion at its lower speed. The scraper bars 18 of the lower run 16 of the conveyor 14 propel the settled sludge along the tank bottom and up the inclined bottom of the structure 11 from where it is discharged at 45 into a waste skip or another container means. As the material moves up the slope of the structure 11, the surplus water is drained therefrom and returns to the tank 1. This operation continues until the timer T4 reaches its pre-set time.

The sludge of small aggregate, sand and cement discharged at 45 can be used as fill.

Thus, it will be seen that the machine according to the invention serves to clean the mixer drum; to separate and clean aggregate for further use; and to collect the separated sludge for further use as fill. It will further be appreciated that the method of operation of the unit serves to conserve water in that the water which is used is returned to the tank 1.

WHAT WE CLAIM IS: 1. A method of reclaiming the residue of concrete in a concrete mixer drum, which comprises passing water from a water-filled settling tank into the drum, discharging the resultant slurry comprising the water and the residue which residue includes aggregate, sand and cement from the drum into the tank, separating within the tank aggregate from the slurry, cleaning and discharging the separated aggregate, allowing the separated slurry to settle in the tank and finally discharging settled sludge comprising the sand and cement from the tank.

2. A method as claimed in claim 1, in which the water in the tank is continually cleaned and re-used.

3. A unit for reclaiming the residue of concrete in a concrete mixer drum, which unit comprises a settling tank, a first structure provided at one end of the tank and having means for separating aggregate of the residue, means for cleaning separated aggregate, and means for discharging the separated aggregate, a second structure provided at the other end of the tank and having discharge means for settled sludge comprising sand and cement, a support plate to receive the residue from the mixer drum, the support plate being positioned in the tank and having a horizontally disposed portion and a portion extending upwardly into the first structure, an endless conveyor extending between the first and second structures, an upper run of the conveyor serving to transport the residue to the aggregate separating and cleaning means and a lower run of the conveyor serving to transport the settled sludge to the discharge means of the second structure, and water supply means, including a pump, for passing water from the tank to the mixer drum and for passing water from the tank to the aggregate separating and cleaning means.

4. A unit as claimed in claim 3, in which the endless conveyor comprises a pair of spaced apart drag chains supported by driven and idler sprockets and having spaced apart scraper bars extending between the chains.

5. A unit as claimed in claim 4, wherein drive is imparted to the driven sprockets by means of a two-speed motor.

6. A unit as claimed in any one of claims 3 to 5, in which the aggregate separating means comprise a vibratory screen.

7. A unit as claimed in any one of claims 3 to 6, in which the water supply means comprises a water pump supported in the tank so that, in use, it is below the water level, and a control valve for selectively passing water to the mixer drum and to the aggregate separating and cleaning means.

8. A unit as claimed in any one of claims 3 to 7, in which the aggregate cleaning means comprise a water spray pipe.

9. A unit as claimed in any one of claims 3 to 8, including a hopper for directing the residue onto the aggregate separating means.

10. A unit for reclaiming the residue of concrete in a concrete mixer drum, substantially as hereinbefore described, with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (11)

**WARNING** start of CLMS field may overlap end of DESC **. the conveyor starts to operate at the higher speed, the pump 33 delivers water to the spray bar 40 and the spray pipe 41, and tuners T1 and T2 are energised. During this part of the operation, the waste, i.e. aqueous slurry containing aggregate, sand and cement, is propelled along the support plate 12 by the scraper bars 18 in the upper run 15 of the conveyor and is discharged at 13 into the hopper 6 from which it is deposited on the vibratory screen 7. The mesh size of the screen is such, for example, that the + 3/16" material (larger aggregate) is discharged over the screen into the chute 10 to a waste skip or other container for re-use, and the - 3/16" material (smaller aggregate, sand and cement slurry) passes through the screen into the water in the tank to settle on the tank bottom. It will be appreciated that the spray bar 40 serves to keep the scraper bars 18 free of deposits and also assists in separating the larger and smaller materials. Also, the nozzles 42 of spray pipe 41 serve effectively to clean the larger aggregate before it is discharged. en timer T2 "times out", timer T3 is energised and the conveyor 14 ceases to operate. However, the spray bar and spray pipe continue for a further minute to cleanse the conveyor, the hopper 6 and screen 7. The unit then remains inactive to allow the smaller material to settle. When timer T3 reaches its pre-set time, the timer T4 is energised and the conveyor 14 is set in motion at its lower speed. The scraper bars 18 of the lower run 16 of the conveyor 14 propel the settled sludge along the tank bottom and up the inclined bottom of the structure 11 from where it is discharged at 45 into a waste skip or another container means. As the material moves up the slope of the structure 11, the surplus water is drained therefrom and returns to the tank 1. This operation continues until the timer T4 reaches its pre-set time. The sludge of small aggregate, sand and cement discharged at 45 can be used as fill. Thus, it will be seen that the machine according to the invention serves to clean the mixer drum; to separate and clean aggregate for further use; and to collect the separated sludge for further use as fill. It will further be appreciated that the method of operation of the unit serves to conserve water in that the water which is used is returned to the tank 1. WHAT WE CLAIM IS:

1. A method of reclaiming the residue of concrete in a concrete mixer drum, which comprises passing water from a water-filled settling tank into the drum, discharging the resultant slurry comprising the water and the residue which residue includes aggregate, sand and cement from the drum into the tank, separating within the tank aggregate from the slurry, cleaning and discharging the separated aggregate, allowing the separated slurry to settle in the tank and finally discharging settled sludge comprising the sand and cement from the tank.

2. A method as claimed in claim 1, in which the water in the tank is continually cleaned and re-used.

3. A unit for reclaiming the residue of concrete in a concrete mixer drum, which unit comprises a settling tank, a first structure provided at one end of the tank and having means for separating aggregate of the residue, means for cleaning separated aggregate, and means for discharging the separated aggregate, a second structure provided at the other end of the tank and having discharge means for settled sludge comprising sand and cement, a support plate to receive the residue from the mixer drum, the support plate being positioned in the tank and having a horizontally disposed portion and a portion extending upwardly into the first structure, an endless conveyor extending between the first and second structures, an upper run of the conveyor serving to transport the residue to the aggregate separating and cleaning means and a lower run of the conveyor serving to transport the settled sludge to the discharge means of the second structure, and water supply means, including a pump, for passing water from the tank to the mixer drum and for passing water from the tank to the aggregate separating and cleaning means.

4. A unit as claimed in claim 3, in which the endless conveyor comprises a pair of spaced apart drag chains supported by driven and idler sprockets and having spaced apart scraper bars extending between the chains.

5. A unit as claimed in claim 4, wherein drive is imparted to the driven sprockets by means of a two-speed motor.

6. A unit as claimed in any one of claims 3 to 5, in which the aggregate separating means comprise a vibratory screen.

7. A unit as claimed in any one of claims 3 to 6, in which the water supply means comprises a water pump supported in the tank so that, in use, it is below the water level, and a control valve for selectively passing water to the mixer drum and to the aggregate separating and cleaning means.

8. A unit as claimed in any one of claims 3 to 7, in which the aggregate cleaning means comprise a water spray pipe.

9. A unit as claimed in any one of claims 3 to 8, including a hopper for directing the residue onto the aggregate separating means.

10. A unit for reclaiming the residue of concrete in a concrete mixer drum, substantially as hereinbefore described, with reference to the accompanying drawings.

11. A method of reclaiming the residue

of concrete in a concrete mixer drum, substantially as hereinbefore described.