Concrete batching plant having reduced cycle time and reduced installation and dismantling time

Abstract

A method of operating a concrete batching plant includes loading aggregates into an aggregate storage bin divided into compartments from the ground level by wheel loader, discharging the material from storage bin through batching gates fitted into a weighing hopper, hydraulically lifting the aggregates after being weighed in the weighing hopper, conveying cement through a screw conveyor into a cement weigher and discharging the same into a mixer, mixing and compacting the aggregates for a pre-determined time, discharging the mixed and compacted concrete into a concrete carrying hopper, transporting the concrete carrying hopper to a desired height, and loading the concrete into mobile transit mixer or concrete pump, based on the site requirement.

Claims

1. A concrete batching plant with reduced cycle time, comprising: an aggregate storage bin divided into compartments for receiving aggregates comprising sand and stones of different sizes; a weighing hopper configured to receive the aggregates from the storage bin; a base structure for discharging a required amount of the aggregates into the weighing hopper mounted on a load cell placed below the storage bin by gravity through batching gates, wherein the aggregate storage bin is configured to be set at a height close to ground level; a wheel loader configured to load the aggregates directly into the storage bin; a lifting arrangement configured to hydraulically lift the weighing hopper with an inclination of a predetermined angle; a gate placed below the weighing hopper and configured to discharge the aggregates into a mixer; horizontal cement silos for supplying cement to the mixer; a screw conveyor with an inclination configured to provide a dose of the cement to the mixer; a cement weigher configured to weigh the cement; a water weigher for weighing water before supplying water to the mixer; and a concrete carrying hopper travelling on a rail hydraulically for discharging contents of the concrete carrying hopper into a transit vehicle.

2. The concrete batching plant as claimed in claim 1, wherein the batching gates are opened and closed by pneumatic cylinders and the weighing hopper is configured to weigh a predetermined amount of the aggregate, thereby eliminating need for a weighing conveyor irrespective of a size and type of the plant.

3. The concrete batching plant as claimed in claim 1, wherein the aggregate weighed by the weighing hopper is lifted pneumatically.

4. The concrete batching plant as claimed in claim 1, wherein the mixer is mounted substantial at the ground level on a column structure.

5. The concrete batching plant as claimed in claim 1, wherein the hydraulically controlled concrete carrying hopper is lifted on rail by at least one of a rope and pulley system to reach a desired height.

6. The concrete batching plant as claimed in claim 1, wherein the horizontal cement silos have a discharge height of between about 2.5 meters and about 3.5 meters and a charging height between of about 7 meters and about 8 meters.

7. The concrete batching plant as claimed in claim 1, wherein the cement weigher is mounted above the mixer with an inlet height between of about 2.5 meters and 4.5 meters.

8. The concrete batching plant as claimed in claim 1, wherein the water weigher is mounted above the mixer at a height of about 3.5 meters and is configured to discharge water into the mixer by at least one of gravity, a pump, and a pressure nozzle.

9. A concrete batching plant, comprising: an aggregate storage bin including a plurality of compartments configured to receive a material comprising sand and stones of different sizes at ground level from a wheel loader; a plurality of batching gates filled at a bottom of the storage bin, and configured to discharge the material from the storage bin; a weighing hopper configured to receive the material from the storage bin and weigh the material; a first lifting arrangement configured to hydraulically lift the weighing hopper from a height of between about 2 meters and about 3 meters, to a height of between about 3 meters and about 3.5 meters above ground level; a screw conveyer configured to convey cement; a cement weigher configured to receive the cement via the screw conveyer; a mixer configured to receive the cement from the cement weigher; a water supplying apparatus configured to discharge water into the mixer via at least one of gravity, a pump, and a pressure nozzle, wherein the mixer is configured to mix and compact the material, the water and chemicals for a predetermined time to create a mixed and compacted concrete; a concrete carrying hopper configured to receive the mixed and compacted concrete from the mixer; a second lifting arrangement configured to lift the concrete carrying hopper with the mixed and compacted concrete to a desired height, wherein the second lifting arrangement includes at least one of a hydraulic lift, a rail, a rack-and-pinion, and a rope; and at least one of a mobile transit mixer and a concrete pump configured to receive the mixed and compacted concrete from the concrete carrying hopper.

Description

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

(1) The nature and scope of the present invention will be better understood from the accompanying drawings, which are by way of illustration of a preferred embodiment and not by way of any sort of limitation. In the accompanying drawings:—

(2) FIG. 1A shows the elevation view of a concrete batching plant of the prior art;

(3) FIG. 1B shows a plan view of a concrete batch plant of FIG. 1A;

(4) FIG. 2 shows the elevation view of a concrete batching plant as per the present design;

(5) FIG. 3 is a partially profiled elevation view of the concrete mixing plant with wheel loader and aggregate bin of FIG. 2;

(6) FIG. 4 is a partially profiled elevation view of the concrete mixing plant with aggregate bin and weighing hopper of FIG. 2;

(7) FIG. 5 is a partially profiled elevation view of the concrete mixing plant with concrete mixer, cement silo and other accessories of FIG. 2;

(8) FIG. 6 is a partially profiled elevation view of the concrete mixing plant with concrete mixer, cement silo, concrete hopper and transit mixer of FIG. 2;

(9) FIG. 7 is the plan view of the concrete mixing plant of FIG. 2;

(10) FIG. 8 is the side view of the concrete mixing plant along the line Z-Z of FIG. 7;

(11) FIG. 9 is a time cycle chart as per conventional design; and

(12) FIG. 10 is a time cycle chart as per the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(13) Having described the main features of the invention above, a more detailed and non-limiting description of a preferred embodiment will be given in the following paragraphs with reference to the accompanying drawings.

(14) In all the figures, like reference numerals represent like features. Further, the shape, size and number of the devices shown are by way of example only and it is within the scope of the present invention to change their shape, size and number without departing from the basic principle of the invention.

(15) Further, when in the following it is referred to “top”, “bottom”, “upward”, “downward”, “above” or “below”, “right hand side”, “left hand side” and similar terms, this is strictly referring to an orientation with reference to the apparatus, where the base of the apparatus is horizontal and is at the bottom portion of the figures. The number of components shown is exemplary and not restrictive and it is within the scope of the invention to vary the shape and size of the apparatus as well as the number of its components, without departing from the principle of the present invention.

(16) All through the specification including the claims, the technical terms and abbreviations are to be interpreted in the broadest sense of the respective terms, and include all similar items in the field known by other terms, as may be clear to persons skilled in art. Restriction or limitation if any referred to in the specification, is solely by way of example and understanding the present invention.

(17) The present invention provides a concrete batching plant for weight batching and mixing of cement with various aggregates, water and chemicals to make concrete. The concrete batching plant of the present invention has reduced structure which makes it easy to install, requires less space for setting up the plant and is fast in dismantling and re-built the plant.

(18) As stated earlier, the improved concrete batching plant according to the present invention has been provided with several new and inventive features. A non-limiting list of these features is as under: 1. Aggregates are loaded directly into the aggregate storage bin, divided into several compartments for each aggregates, using wheel loader from the ground level. Thereby eliminating ramp for loading material to aggregate storage bin or to ground hopper. Also eliminating conveyor requirements for transferring aggregate from ground hopper to aggregate storage bin. 2. Batching of aggregates is done in the weighing hopper mounted on load cell placed below the aggregate storage bin. 3. Weighing conveyor is eliminated irrespective of the size and type of the plant. 4. Weighed aggregates in the weighing hopper are lifted from 2 mtrs to 3 mtr-3.5 mtr. above the ground hydraulically or weighed aggregates is lifted pneumatically. 5. Mixer is mounted just 1.3 mtrs above the ground level or almost at the ground level on a simple column structure. 6. Weighing hopper is lifted hydraulically up to 2 to 3 mtrs height and directly discharged material in to the mixer. 7. Cement weigher is mounted just above the mixer with inlet height average around 3.5 mtr (±1 mtr). 8. Dosing of cement is done with the help of a short screw conveyor which is only about 4.5 mtrs long and with a small inclination. 9. Cement silos are horizontal type with discharge height of around 2.5 mtr-3.5 mtr and charging height of around 7 to 8 mtrs. This can also be vertical type with a discharge height of about 2 to 3 mtrs. 10. Cement Weigher is mounted on simple beam fixed on the cement silos and has 2 discharge points for faster discharge and to improve the spread of material in the mixer. 11. Water weigher is mounted just above the mixer at a height of around 3.5 mtrs and is discharged into mixer either by gravity or by pump/pressure nozzle. 12. Concrete mixed in the mixer is discharged up to a carrying hopper and this hopper is lifted up hydraulically. 13. Concrete carrying hopper moves on a fixed rail and then discharges concrete into truck mounted transit mixer directly or through a waiting hopper.

(19) Referring now to FIGS. 1A and 1B which shows the elevation and plan view respectively of the concrete batching plant of the prior art. With reference to FIG. 1A, the entire assembly of concrete batching plant is having heavy and a rigid structural frame for mixer and the aggregate bin. Heavy Structures are also required for the Belt Conveyor carrying weighing conveyor to the mixer. A ramp is created for the wheel loader to load the aggregates in the aggregates bins or Aggregates are loaded in to a ground hopper. A Conveyor with feed point below the ground hopper carries the aggregates over a particular distance and height and discharges into aggregate storage bins. The aggregates are released from the aggregate bins onto weighing belt conveyor through aggregates dosing cones with the help of batching gates. Batching of aggregates is done by weighing conveyor for higher capacity plants suspended on load cells or by skip bucket suspended on load cells placed below the aggregate storage bins. Weighed aggregates are lifted up to a height of around 6.5 mtr. to 7 mtr. by another inclined conveyor carrying the material from the weighing conveyor to the mixer or up to a height of around 5 mtr. by a skip rope and pulley drum arrangement. Concrete mixer is mounted on a fabricated heavy structure mounted on civil foundations or on steel mobile foundations. Steel structure housing the mixer, cement weigher and water weigher are as tall as 8 mtr. to 10 mtr and as heavy as up to 15 tons. Weighed aggregates can also be discharged into the mixer either by lifting the skip buckets up to 7 to 9 mtr height or by rotating the heavy skip bucket above the mixer at a height of around 9 mtr.

(20) In a batching plant where conveyors are used to weigh and carry aggregates, conveyor discharges the material into a waiting hopper which is about 2 mtr above the mixer. Cement weigher is mounted above the mixer and inlet of the same is at a height ranging from 6.5 to 9.5 mtr. Dosing of cement is done with the help of screw conveyors which are around 10 to 14 mtr long depending on the capacity of the plant and is erected with inclination 45° and above. Cement silos are vertical type and are with discharge height of 2 to 3 mtr from the ground and charging height is almost at 13 mtrs to 20 mtr depending on the capacity of the silos. Cement weigher is mounted on heavy structures and is placed above the mixer with single discharge. Water weigher is mounted above the mixer at around 6.5 mtr to 9 mtr height and is discharged into mixer either by gravity or by pump/pressure nozzle. Concrete mixed in the mixer is discharged directly into the truck mounted transit mixer placed below the mixer.

(21) Referring now to FIG. 3 the concrete batching plant according to the present invention comprises of a aggregate storage bin (2), divided into several compartments for each aggregate, through which the required amount of aggregates for preparing the concrete are discharged into a weighing hopper (5) through batching gate (3). The crux of the invention lies here in that the aggregate bin (2) are set at a height close to the ground level in comparison with the conventional types, so that the aggregates can be loaded directly into the bin using the wheel loader (1) from the ground level. The aggregate bin are supported on a support base structure (4). As the storage bin (2) are close to the ground level, it is easy to dismantle as compared to the heavy fabricated structures.

(22) A non-limiting list of advantages of the above described features is as under: Cost reduction due to elimination of ground hopper Cost reduction due to elimination of aggregate bin feeding conveyor Cost reduction due to elimination of ramp for the wheel loader to load material into to aggregate storage bins or to a ground hopper. Operation cost reduction due to elimination of conveyor motor and swiveling motor for the rotating chute. Operational cost reduction due to diesel consumption and tyre wear of loader due to inclination of ramp. Reduction in Maintenance cost as high maintenance conveyor is eliminated. Lower maintenance of the vehicle due to shorter lead to stock piles. Since the loading of aggregates into storage bin is carried out from ground level, the travel of loader reduces and smaller size of aggregate storage bin is enough to produce concrete continuously. In case, the higher capacity of the plant is required then same capacity storage bins can be used by deploying two loaders. Cost of aggregate storage bin is reduced to great extent as they have a simpler manufacturing process.

(23) Referring now to FIG. 4, aggregates are discharged from aggregate storage bin (2) through batching gates (3) by gravity into weighing hopper (5) mounted on load cell (6) placed below the aggregate storage bin (2). The opening and closing of the batching gates (3) is done with the help of pneumatic cylinders. The aggregates are weighed, as per requirement, in the weighing hopper (5) itself. The crux of the invention lies here in that the weighing conveyor is eliminated irrespective of the size and type of the plant and the weighed material is lifted from 2 mtrs to 3 mtr-3.5 mtr. above the ground hydraulically (8) with an inclination of angle A° for discharge into the mixer by the help of gate (7) placed below the weighing hopper. In another embodiment, the weighed aggregates can also be lifted pneumatically.

(24) Advantages of the above inventive features: By eliminating the weighing conveyor, cost of the plant is reduced considerably. Operational cost reduced as the motor required for running weighing conveyor is eliminated. Maintenance cost reduces as the weighing conveyor maintenance gets eliminated. Lifting of aggregates by skip rope, pulley is eliminated and this reduces the initial cost, operational cost and maintenance cost. Lifting of aggregates by conveyor is eliminated which also reduces the initial cost, operational cost and maintenance cost. Increases safety as rope breaking, bucket falling and conveyor snapping is eliminated.

(25) Referring now to FIG. 5, the material from the weighing hopper (5) is discharged to the mixer (9). The mixer (9) is mounted just 1.3 mtrs above the ground level or almost at the ground level on a simple column structure (14). The concrete mixer is capable of mixing the material, including cement, water and aggregates etc. to prepare the concrete.

(26) Advantages of the above inventive features: his eliminates the heavy tall steel structural fabrication which is required for mounting the mixer. Cost of heavy structural steel is eliminated. Cost of large quantity of fabrication, surface preparation and painting is eliminated. This in turn reduces the manufacturing and delivery time of the plant and this result in redemption of inventory. Tools and tackles required for erection of the plant is reduced and also the time required for erection of the plant and dismantling of the plant is also reduced.

(27) Cement is supplied to the mixer (9) from a cement silo (10). Cement silos are horizontal type with discharge height between 2.5 mtr to 3.5 mtr and charging height to between 7 mtr to 8 mtr. This can also be vertical type with a discharge height of about 2 mtr. to 3 mtr. Simultaneously, water is supplied to the water weigher through a water pipeline. The cement weigher (11) is mounted just above the mixer with an inlet height of approximately 3.5 mtr (±1 mtr). Dosing of cement is done with the help of a short screw conveyor (12) which is only about 4.5 mtrs long and with a small inclination. The cement and water are weighed by respective weighers (11 and 13), as per requirement, before supplying to the mixer (9).

(28) The cement weigher (11) is mounted on a simple beam fixed on the cement silos and has two discharge points for achieving faster discharge and to improve the spread of material in the mixer. The water weigher (13) is mounted just above the mixer at a height of around 3.5 mtrs and is discharges water into the mixer either by gravity or by pump/pressure nozzle.

(29) Advantages of the above inventive features: Cement dosing screw is around 4.5 mts. length instead of 10 to 14 mtrs. in the conventional system. This reduces the cost of the screw conveyor. Reduces the power consumption to almost 40% due to reduction in length and inclination of screw conveyor. Reduces the maintenance cost and down time due to elimination of hanger bearings of screw conveyor. Cement silos can be both vertical and horizontal type. With horizontal cement silos the height of the silo reduces and the heavy foundation cost is substantially reduced and maintenance of the silo becomes easy due to reduction of structures. Time for project completion is reduced with horizontal silo cement charging into silos consumes less power/diesel.

(30) Referring now to FIG. 6, all ingredients are mixed in the mixer (9) and the concrete is discharged into a concrete carrying hopper (15). Hopper (15) carrying concrete travels on a rail (16) hydraulically to reach the desired height to discharge its contents into transit mixer (18) mounted on truck through gates (17).

(31) Alternatively, hopper (15) carrying concrete is lifted up through a rope pulley system to reach the desired height to discharge into transit mixer (18) or lifted up by rack and pinion system to reach the desired height into transit mixer. It will be clear to a person skilled in the art that other types of carrying mechanism are also possible, which are all part of the present invention, as long as they allow easy lifting of the concrete hopper (15).

(32) Advantages of the Above Inventive Feature:

(33) Lifting the finished product i.e. concrete to the height of loading to transit mixer instead of lifting aggregates and mixing at a height which is as per the conventional way of concrete manufacturing is much more economical and saves time.

(34) Method of Operating the Concrete Batching Plant According to Present Invention:

(35) Referring now to FIGS. 2, 7 and 8, aggregates comprising sand and stones of different sizes are loaded into a aggregate storage bin (2), divided into several compartments for each aggregate, from the ground level by wheel loader (1). Different sizes of aggregates are stored in the different compartments of the same Aggregate Storage Bin. Storage bin is fitted with batching gates (3) at the bottom, as best shown in FIG. 2, through which material is discharged into the weighing hopper (5) by gravity. Aggregates which are weighed in the weighing hopper are lifted from 2 mtrs to 3 mtr-3.5 mtr above the ground level hydraulically (8) or weighed aggregates are lifted pneumatically. Cement is simultaneously conveyed through a screw conveyor (12) into a weigher and the same is discharged into the mixer (9). Aggregates, cement, water and chemicals are discharged into the mixer and are mixed for a pre-determined time.

(36) Mixed and compacted concrete is discharged into a concrete carrying hopper (15) which transports the carrying hopper (15) with the concrete to desired height through either lifted hydraulically on rail (16), rack and pinion or rope arrangement to achieve loading of the concrete into mobile transit mixer (18) or concrete pump, based on the site requirement and condition.

INDUSTRIAL APPLICATION

(37) Due to simplification of the processes of making the concrete the present invention have the following advantages: Batching Transferring of aggregates from weigher to mixer Cement storage, dosing, discharge the rate of concrete discharge from the mixer to concrete hopper by having two openings or bigger openings and lifting the concrete hopper to desired height for loading the truck mounted transit mixer. This will help in reducing the initial cost of the equipment to great extent. By optimizing the sequence layout and timing of operation installed power is reduced to 60% of the conventional similar capacity plant. How the same is achieved is described in Table I. The cycle time of the plant is optimized to have higher capacity of the plant in Cubic Metre/hour by reducing the batch size of the mixer nearly 45%. How the achieved is described in Table II and Table III and FIGS. 9 and 10 for a 120 m.sup.3/hr capacity batching plant of concrete production. The present invention is valid for various capacities from 20 m.sup.3/hr up to 240 m.sup.3/hr of concrete production.

(38) TABLE-US-00001 TABLE I INSTALLED POWER CALCULATION FOR 120 CM PER HOUR CAPACITY CONCRETE BATCHING PLANT NEW DESIGN With aggregate bins height With aggregate bins height 2.7 mtrs above the ground. 3.9 mtrs above the ground. Aggregate loading by loader Aggregate loading by super from ground height. Weighed loader from ground height. PRESENT DESIGN aggregates moved to mixer Weighed aggregates moved ACTIVITY SKIP TYPE CONVEYOR TYPE Hydraulically to mixer Hydraulically Aggregate bin feeding conveyor 20 KW 20 KW — — Aggregate weighing conveyor — 22.5 KW   — — Skip motor 45 KW — — — Inclined conveyor for mixer — 55 KW — — loading Aggregate hopper for mixer — — 28 KW 28 KW loading and concrete hopper carrying together hydraulically. Mixer motor 110 KW  110 KW  60 KW 60 KW Cement dosing Screw conveyor 18.5 × 2 = 18.5 × 2 = 7.5 × 2 = 7.5 × 2 = 37 KW 37 KW 15 KW 15 KW High Pressure water pump 7.5 KW  7.5 KW  7.5 KW  7.5 KW  Total 219.5 KW   252 KW  110.5 KW   110.5 KW   Note: Other smaller common power requirements not considered.

(39) TABLE-US-00002 TABLE II COMPARISON OF TIME CYCLE FOR EACH ACTIVITY: Present Conventional Batching batching Plant List of Activities Plant (time in sec.) (time in sec.) Batching Aggregate (size: 4 + 1 4 + 1 2-8 mm) Batching Aggregate (size: 7 + 1 6 + 1 0-2 mm) Batching Aggregate (size: 4 + 1 4 + 1 8-16 mm) Batching Aggregate (size: 7 + 1 6 + 1 16-32 mm) Discharge of Weighing 27 — Belt Aggregate weighing — 10 hopper travel Conveyance to 27 + 24 — Intermediate hopper Aggregate Weighing — 08 hopper discharge Intermediate hopper 14 — discharge Aggregate weighing — 07 hopper back to initial position Batching cement 54 + 1  27 + 1  Discharge cement 11 09 Batching water 33 + 1  22 + 1  Discharge water 17 15 Mixing time 30 30 Discharging mixer 38 10 Closing mixer gate  3  2 Concrete Hopper up — 09 Concrete hopper — 22 discharge Concrete hopper gate — 02 close Concrete hopper down — 06

(40) TABLE-US-00003 TABLE III COMPARISON OF TIME CYCLE FOR BATCH: Parameter Conventional Present invention Batch Size 3 m.sup.3 1.67 m.sup.3 1.sup.st batch time 147 Sec. 132 Sec. 2.sup.nd batch time 90 Sec. +/− 6 Sec. 50 Sec. (+/−8%~10%) onward Batch through 120 m.sup.3/hr +/− 8~10 m.sup.3/hr. 120 m.sup.3/hr (+/−8%~10%) put/hr

(41) The present invention has been described with reference to some drawings and a preferred embodiment purely for the sake of understanding and not by way of any limitation and the present invention includes all legitimate developments within the scope of what has been described herein before and claimed in the appended claims.