Device for working up unused concrete mix and/or mortar

Abstract: The invention relates to a method for working up unused concrete mix and/or mortar whereby the unused concrete mix and/or mortar is gradually supplied to and distributed over a sieve (4) during spraying of the unused concrete mix and/or mortar with water in such a way, that grit or the like which is in the unused concrete mix and/or mortar is cleaned by rinsing and remains on the sieve (4) in order to be discharged therefrom. The material passing through the sieve and consisting of a mixture of sand, cement and water, is supplied to a separation device (10) wherein the sand is separated from said mixture. The remaining mixture of water and cement is returned at least partly from the discharge (11) of said separation device (10) towards the supply side of the separation device (10).

Description: The invention relates to a device for the separate recovery of coarse aggregates, fine aggregates and residual water from concrete mix and/or mortar comprising a collecting tank for receiving the concrete mix and/or mortar, conveyor means in said collecting tank for supplying the concrete mix and/or mortar to a vibrating sieve, spraying means arranged above said vibrating sieve for supplying water to said vibrating sieve, a further collecting tank below said vibrating sieve for collecting a mixture of water, sand and cement passing through said vibrating sieve, pump means for passing said mixture from said further collecting tank towards a separating device separating sand from said mixture, said separating device having a first outlet for discharging sand and a second outlet for discharging a mixture of water and sand. Such a device is known from the Dutch patent application NL-A-8701253. In principle said device is satisfying, however in practise it has been shown, that there is a need for a still beter separation of the mixture of sand, cement and water. It has appeared, that this can be obtained by improving the sieve action and by increasing the capacity of the separation device which requires however also an increase of water supplied to the separation device. Now according to the invention the first outlet of the separating device is in communication with a further vibrating sieve situated remote from said first cited vibrating sieve whilst the second outlet of the separating device is in communication with the upper end of a substantially vertical duct, at least a part of said duct being flexible and drive means being provided for displacing the lower discharge end of said duct between a first position wherein said duct is in communication with a return duct for returning the mixture of water and sand from said duct towards the further collecting tank and a second position wherein said duct is in communication with a buffer tank having at its upper end an overflow for discharging water and further discharge means for discharging a concentrated mixture of water and cement. In using the device according to the invention the quantity of liquid required by the increased capacity of the separation device can be maintained at the required level in a simple way by replenishment of the water used for spraying of the unused concrete mix and/or mortar in order to clean the grit and the like by rinsing with a part of the water which is passed through the separation device and contains only cement. Thereby the flow of water from the separation device can be controlled by simple means without valves or the like coming into contact with water loaded with cement. The separation will be further improved by the further vibrating sieve which works independently of the first sieve. It is noted that from EP-A-0 269 576 there is known a device for the separate recovery of aggregates, residual water and cement from concrete mix having a sieve whereon the load of a mixer can be dumped. Above said sieve there has been mounted a further sieve. Below said sieves there has been arranged a collecting tank. Through said collecting tank there extends a water discharge duct of a separating device. Said water discharge duct comprises a valve mechanism arranged in said collecting tank for admitting water from said discharge duct into said collecting tank, if desired. Hereinafter the invention will be explained by means of the enclosed figure wherein a device according to the invention has been shown diagrammatically. The operation of said device corresponds mainly with the operation of the device described in the above cited Dutch patent application NL-A-8701253 and it is deemed, that the contents of said application has been included here, so that it will not be necessary to explain in a detailed way the working of the various parts of said device. The device shown in the figure comprises a collecting tank 1 wherein unused concrete mix and/or mortar, e.g. from a customary truck for transporting concrete or mortar can be dumped. In a lower part of the collecting tank there has been mounted a conveyor screw 2. Further there has been mounted a spray duct 3 in the collecting tank 1. As has been described in the Dutch patent application NL-A-8701253 the material dumped in the collecting tank 1 is supplied to a vibrating sieve 4 by means of the conveyor screw 2, whilst above the vibrating sieve 4 there has been arranged a spray duct 5. By spraying the unused concrete mix and/or mortar on the vibrating sieve the grit or the like in the unused concrete mix and/or mortar is separated and is dumped on a conveyor belt 6 near one end of the vibrating sieve, whilst a mixture of sand, water and cement passes through the sieve and is discharged to a collecting tank 7 arranged below said sieve. By means of the conveyor belt 6 the grit is dumped e.g. on a heap 8 so that it eventually can be used again. The mixture of water, cement and sand collected in the collecting tank 7 can be supplied to a cyclone separation device by means of a pump 9, said separation device 10 being sized in such a way, that in said separation device the coarse parts of the mixture formed by the sand are separated and are supplied to a vibrating sieve 12 by means of a discharge duct 11. The sand lying on the vibrating sieve 12 is sprayed once more by means of water supplied via a spray duct 13 in order to separate any remaining cement from the sand. Sand falling from an end of the vibrating sieve 12 is discharged by means of a conveyor belt 14 and e.g. dumped on a heap 15 so that it eventually can be used again. The mixture of water and cement separated from the mixture of sand, water and cement in the separation device is discharged via a duct 16. At least the lower end of the duct 16 has been flexible in such a way, that the duct 16 can be displaced in a horizontal direction as indicated by means of the double arrow A over a particular distance by means of an adjusting mechanisme 17. The open lower end of the duct 16 is situated at the level of the upper side of a buffer tank 18 namely near a supply opening 19 situated near the upper side of said buffer tank 18. Near the supply opening 19 there has been fixed a collecting bin 20 to a side of the buffer tank 18, said collecting bin 20 being separated of the supply opening 19 by means of a partition 21. By displacing the duct 16 in the direction according arrow A by means of the adjusting device 17 the open lower end of the duct can be arranged in a first position, wherein the mixture of water and cement flowing from the duct 16 flows in the buffer tank 18, and in a second position wherein said mixture flows from the duct 16 into the collecting bin 20. By means of a duct 22 the collecting bin 20 is in open communication with the collecting tank 7, so that then the mixture of water and cement flowing from the duct 16 can be returned towards the collecting tank 7 via de collecting bin 20. The adjusting device 17 can be operated automatically depending on the level of the water in the collecting tank 7, so that said collecting tank will be always filled in a sufficient way. By using the displaceble duct 16 there are not needed valves of the like for diverting the water flow from the duct 16 towards the buffer tank 18 or towards the collecting tank 7, such valves or the like being liable for jamming. As also will be clear from the figures the mixture of water and cement coming from the vibrating sieve will be supplied directly to the collecting bin 20 via een duct 23 and from said collecting bin 20 towards the collecting tank 7. In the collecting tank 18 wherein the mixture of cement and water is supplied, the cement can settle and from time to time there can be discharged water, substantially free of cement via a overflow tank 24 towards supply vessels 25 from which the water can be pumped by means of a pump 26 and can be supplied to various spraying means for spraying purposes as will be clear from the diagram shown in the figure. From time to time a concentrated mixture of water and cement, which can be agitated by means of an agitating device 27 mounted in the buffer tank can be discharged via a duct 28 connected on the tank and a pump 29 in order to be used again for the manufacturing of new concrete.

Claims: Device for the separate recovery of coarse aggregates, fine aggregates and residual water from concrete mix and/or mortar comprising a collecting tank (1) for receiving the concrete mix and/or mortar, conveyor means (2) in said collecting tank (1) for supplying the concrete mix and/or mortar to a vibrating sieve (4), spraying means (5) arranged above said vibrating sieve (4) for supplying water to said vibrating sieve (4), a further collecting tank (7) below said vibrating sieve for collecting a mixture of water, sand and cement passing through said vibrating sieve (4) pump means (9) for passing said mixture from said further collecting tank (7) towards a separating device (10) separating sand from said mixture; said separating device having a first outlet for discharging sand and a second outlet for discharging a mixture of water and sand, characterized in that the first outlet of the separating device (10) is in communication with a further vibrating sieve (12) situated remote from said first cited vibrating sieve (4) and that said second outlet of the separating device (10) is in communication with the upper end of a substantially vertical duct (16), at least a part of said duct (16) being flexible and drive means (17) being provided for displacing the lower discharge end of said duct between a first position wherein said duct (16) is in communication with a return duct (22) for returning the mixture of water and sand from said duct (16) towards the further collecting tank (7) and a second position wherein said duct (16) is in communication with a buffer tank (18) having at its upper end an overflow for discharging water and further discharge means (28, 29) for discharging a concentrated mixture of water and cement. Device according to claim 1, characterized in that near the top of the buffer tank (18) there has been mounted a collecting bin (20), which is separated from a supply opening (19) of the buffer tank (18) by means of a partition (21) and whereby the arrangement is so that the open lower end of the duct (16) can be moved to and fro between a position at one side of said partition (21) to a position at the other side of said partition (21). Device according to claim 1 or 2, characterized in that there are provided spray means (13) for supplying water on said further sieve (12) and a water discharge duct (23) for discharging water from said further sieve (12) towards said further collecting tank (7). Device according to any of the preceding claims, characterized in that in the collecting tank (7) there has been mounted a pump (9) for pumping the mixture of water, sand and cement from said collecting tank towards the separation device (10).

Inventors: BOSCH BERTHOLDUS PETRUS, BOSCH, BERTHOLDUS PETRUS
Applicants: HEIJMANS MATERIEEL BEHEER, HEIJMANS MATERIEEL BEHEER B.V.
Application year: 1992
Main classification: B09B3
IPC codes: B03B9, B09B3