Claims:We claim,

1. A continuous mixing plant (1) for continuous production of composite construction materials according to the present invention comprising:

a continuous mixing unit (2) includes a continuous mixer (3) supported on a steel structure (4) having an inlet hoppers (5 and 6) for receiving of aggregates and cementitious ingredients respectively into the continuous mixer (3); said continuous mixing unit (2) is equipped with a couple of helibevel gearbox (24) and a motor (25) to drive the continuous mixer (3), at least a couple of spur gears (38) being fitted on the continuous mixer (3) for synchronizing the speed of the helibevel gearbox (24) and motor (25), a hinge type lockable covers (37) on the top of the continuous mixer (3) for easy maintenance and cleaning purpose;

a feeder unit (7) supported on a steel base frame (8) for storage of aggregates which includes multiple feeder bins (9) having spaced inlet and discharge openings toward opposite ends thereof;

an auxiliary conveyor (10) and a collecting conveyor (11) equipped with auxiliary and VFD units positioned below the feeder unit (7) for receiving the weighed aggregates from the feeder bins (9);

a slinger conveyor (12) positioned with supporting means (19) for continuously supplying the aggregates from the collecting conveyor (11) to the inlet hopper (5) of the continuous mixing unit (2);

a silo (13) of an adequate capacity for storage of cementitious ingredients;

a weighing and conveyance system (14) for cementitious ingredients being supported through a steel structural frame (15) beside the continuous mixer (3);

a water feeding line (16) installed over the continuous mixer (3) has water spray nozzles for feeding water at the inlet of the continuous mixer (3); and a water metering system (17) installed on the water feeding line (16) for measuring the flow of water through the water feeding line (16);

a load out conveyor (18) positioned with supporting means (19) for delivering the mixed materials from the continuous mixer (3) to a gob hopper (20) or a storage silo (36) having spaced opening for receiving the mixed materials and a hydraulic discharge gate (21) for discharging the mixed materials into a receiving truck (22) positioned below the gob hopper (20) or the storage silo (36);

a control cabin (23) located approximately alongside the continuous mixing unit (2) which includes at least a single integrated control panel with a programmable logic controller (PLC) unit for remotely monitoring and controlling the continuous mixing plant (2);

characterized in that said continuous mixer (3) is a pug-mill type twin shaft counter flow continuous mixer (3) being internally lined with Ni-hard adjustable liner tips (34), replaceable liner plates (39), and steel casting paddles (26) for minimum wearing and longer life of the continuous mixing unit (2);

said feeder unit (7) has a level sensor at discharge point for sensing the flow of aggregates from each feeder bin (9), and has a load cell weighing bridge positioned at discharge end below the feeder unit (7) for continuously weighing the aggregates discharged on it from the feeder bins (9);

said weighing and conveyance system (14) for cementitious ingredients includes a weighing hopper (28) suspended with load cells (29) over beside the continuous mixer (3) for weighing of the cementitious ingredients received into the weighing hopper (28) from the silo (13) through a screw conveyor (30); a screw conveyor (30a) mounted with load cells (29a) below the weighing hopper (28) for conveying weighed cementitious ingredients from the weighing hopper (28) into the inlet hopper (6) of the continuous mixer (3); a rotary valve (35) fitted at the bottom of the weighing hopper (28) for regulating the flow of cementitious ingredients from the weighing hopper (28).

2. The continuous mixing plant (1) for continuous production of composite construction materials as claimed in claim 1 wherein the water metering system (17) comprises a non-contact type water flow meter (27) installed on the water feeding line (16) for indicating the flow of water passing through the water feeding line (16); and a water pump equipped with and driven by VFD (variable frequency drive) units for synchronizing the flow of water according to the flow of aggregates and cementitious ingredients into the continuous mixer (3).

3. The continuous mixing plant (1) for continuous production of composite construction materials as claimed in claim 1 wherein the control cabin (23) includes a control panel with VFD (variable frequency drive) units for driving the feeder unit (7), the continuous mixer (3), the water pump and the conveyor (30a) and for synchronizing and controlling the flow of water, aggregates and cementitious ingredients into the continuous mixer (3); a master pot on the control panel to increase or decrease the output of the continuous mixing plant (1).

4. The continuous mixing plant (1) for continuous production of composite construction materials as claimed in claim 1 wherein the auxiliary conveyor (10), the collecting conveyor (11), the slinger conveyor (12) and the screw conveyor (30, 30a) are belt drive conveyors.

5. The continuous mixing plant (1) for continuous production of composite construction materials as claimed in claim 1 wherein a platform (31) with an access ladder (32) and railings (33) are provided at the level of the continuous mixer (3) and weighing hopper (28) for easy maintenance and handling.

Dated this on 26th day of September, 2018
, Description:
FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)

1. TITLE OF THE INVENTION: “A Continuous Mixing Plant for Continuous Production of Composite Construction Materials”
2. APPLICANT:

(a) Name : Maxmech Equipments Pvt. Ltd.
(b) Nationality : Indian
(c) Address : 410, Iscon Elegance,
Nr. Prahalad Nagar, S.G. Highway,
Ahmedabad - 380 015,
Gujarat, India.
PROVISIONAL

The following specification describes the invention. þ COMPLETE

The following specification particularly describes the invention and the manner in which it is to be performed.

Field of invention

The present invention relates to a continuous mixing plant and more particularly it relates to a continuous mixing plant for continuous production of composite construction materials i.e. dry lean concrete, wet and dry mixed material, cement-concrete treated aggregate base material, blanketing material, granular sub base material, fine particles mixing like dry mortar, cement, fly ash and foundry sand.

Background of invention

Since last few decades, the gradual evolution of construction equipments in construction industry has being carrying out for providing an improved alternative than that of the existing ones. In construction industry, the mixing plants have evolved greatly over time, from the simple manual mixing plants to those remotely and automatically operated and regulated by computerized automation system.

A mixing plant is an equipment that combines and mixes/blends various kinds of input ingredients and aggregates to form composite construction materials; and said ingredients and aggregates may include water, air, admixtures and sand; rocks, gravel, fly ash, silica fume, slag and cement. In construction industry, mixing plants play vital role for production of concrete-cement based construction materials i.e. dry lean concrete, wet and dry mixed materials, cement treated aggregate base materials, blanketing materials, granular base materials, fine particles mixing like dry mortar, cement, fly ash and foundry sand.

Presently various kinds of mixing plants are used in construction industry for production of composite construction materials which may include manual mixing plant and batch plant. One of such mixing plants has been disclosed in EP1529617A2 which relates to a concrete-mixing process and plant with mixing of components in the field of the mixing of cement and non-cement aggregates with the mixing of components in the dry state for fine homogenization of the compound. One more such batching and mixing plant has been disclosed in 2070/MUM/2009 which relates to a concrete batching plant for weight, batching and mixing cement with various aggregates, such as water and chemicals to make concrete. However, said prior art patents lack the important features i.e. multiple bin feeder unit, twin shaft continuous mixer and a control cabin having control panel for remotely monitoring and controlling the mixing plant which requires lots of labor consumption and causes poor production and thereby it results in reduced efficiency of the mixing plant. Hence, it is essentially required to increase the efficiency of the mixing plant by increasing the production rate and as well as to diminish the production cost.

In batch mixing plant, the manufacturing equipment uses a lot of space which is wasted if the equipment is idle; and additional labor is needed to move items from one process to another, in addition to the labor needed for batch manufacturing. Further, the batch mixing plant requires reconfiguring the system to produce something different results in downtime which are wasted resources. The main drawback associated with the batch plant is a discontinuous operation which results from the sharp separation of the work cycles.

The ready mixed concrete is manufactured in batch plant which causes loss of workability due to unavailability of immediate placement of concrete mix. In addition, there are chances of setting of concrete if transit time involved is more and therefore generally admixtures like plasticizers or super plasticizers and retarders are required to be added. Addition of such retarders may delay the setting time substantially which may cause placement problems. In addition, it may also affect the strength of concrete. Further, because of large quantity of concrete available in short span, special placing and form work arrangement are required to be made in advance.

In order to cop-up with above difficulties, the demand for continuous mixing plant is gradually increasing in many countries for economic and rapid production of composite construction materials. However, in a lot of cases the present production capacity of the concrete mixing plant can’t be increased and often outdated control systems cause failures and interruptions of the production. The solution for all existing problems of mixing plant is the installation of a new more efficient concrete mixing plant which must be versatile and economically viable.

Therefore, it is really financial constraints that limit the rate of advancement and development in construction industry, and one of the greatest challenges for the new millennium will be to find the way for widespread application of mixing plant’s innovations in construction industry.

In recent years, the technical innovations have combined to develop an innovative mixing plant which would have the advantages of simple structure, easy and fast installation and convenient maintenance which can produce quality mixed concrete based materials in large quantity as per prescribed accuracy. Despite of modern mixing plants, some improvements and adaptation is required for increasing the production rate and efficiency of the mixing plant and thereby reducing the production cost. Although the presently available continuous mixing plants provide numerous advantages, there is still scope for improvements over the existing ones.

Therefore, it is an immediate need to provide the continuous mixing plant which is cost effective and economically viable and that eliminates and obviates the existing problems, shortcomings and inadequacies associated with the existing mixing plants.

Object of Invention

The main object of the present invention is to provide a continuous mixing plant for continuous production of composite construction materials i.e. dry lean concrete, wet and dry mixed material, cement-concrete treated
aggregate base material, blanketing material, granular sub base material, fine particles mixing like dry mortar, cement, fly ash and foundry sand.

Another object of the present invention is to provide a continuous mixing plant for continuous production of composite construction materials which produces quality mixed materials in large quantity as per prescribed accuracy.

Still another object of the present invention is to provide a continuous mixing plant for continuous production of composite construction materials which is versatile, cost effective and economically viable and which involves low investment.

Yet another object of the present invention is to provide a continuous mixing plant for continuous production of composite construction materials which is single plant for multipurpose applications i.e. wet mix macadam plant, concrete batching plant and fine particles blending plant.

Yet another object of the present invention is to provide a continuous mixing plant for continuous production of composite construction materials which has the advantage of easy and fast installation and convenient maintenance with reduced maintenance cost and reduced life cycle cost.

Yet another object of the present invention is to provide a continuous mixing plant for continuous production of composite construction materials which is simple in structure having increased durability of the plant.
Yet another object of the present invention is to provide a continuous mixing plant for continuous production of composite construction materials which overcomes the drawbacks and shortcomings of the prior art mixing plant.

Summary of invention

A continuous mixing plant comprises continuous mixing unit comprised of inlet hopper for receiving and mixing of aggregates, cement and water; a multiple-feeder bin feeder unit for storage of aggregates; auxiliary and collecting conveyors for receiving aggregates from each bin; slinger conveyor for supplying aggregates from collecting conveyor to inlet hopper; a silo for storage of cementitious-ingredients; weighing and conveyance system for weighing and conveying cementitious-ingredients to continuous mixer; a water metering system installed on water feeding line over the continuous mixer for measuring water flow; a load-out conveyor for delivering mixed materials from continuous mixing unit to a gob hopper which discharges mixed materials into receiving truck; a control cabin comprising control panel with PLC unit and variable frequency drive units for remotely monitoring and controlling the plant. The continuous mixing plant according to the present invention is remotely controllable and operable for continuous production of composite construction materials by synchronizing the flow of materials into the continuous mixer which has the advantage of easy and fast installation and convenient maintenance with reduced maintenance cost and reduced life cycle cost.
Brief description of drawings

Fig. 1 shows a perspective view of a continuous mixing plant for continuous production of composite construction materials according to the present invention.

Fig. 2 shows perspective view of continuous mixing plant for continuous production of composite construction materials according another embodiment of the present invention.

Fig. 3 depicts a perspective view of a feeder unit of weighing & conveying of different aggregates according to the present invention.

Fig. 4 depicts a perspective view of twin shaft continuous mixer according to the present invention.

Fig. 5 shows an internal view of the twin shaft continuous mixer according to the present invention.

Fig. 6 depicts a perspective view of a weighing and conveyance system for cementitious ingredients according to the present invention.

Fig. 7 indicates a perspective view of a water feeding system and a water metering system (volumetric) according to the present invention.

Fig. 8 shows an enlarged view of a load out conveyor with gob hopper according to the present invention.

Fig. 9 shows an enlarged view of a load out conveyor with storage silo according to the present invention.

Detailed description of invention

The nature of the invention and the manner in which it works is clearly described in the complete specification. The invention has various embodiments and they are clearly described in the following pages of the complete specification. Before explaining the present invention, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and not of limitation.

Before explaining the present invention it is to be understood that the term “PLC” unit refers to programmable logic controller unit and the term “VFD” unit refers to variable frequency drive unit.

The detailed constructional view of a continuous mixing plant (1) according to the present invention is shown in Fig. 1 and 2. Referring to Figs. 1 and 2, the continuous mixing plant (1) according to the present invention comprises a continuous mixing unit (2) consisting of a twin shaft counter flow continuous mixer (3) supported on a steel structure (4) and having an inlet hoppers (5, 6) [shown in Fig. 4 and 5] for receiving of aggregates and cementitious ingredients respectively into the continuous mixer (3); a feeder unit (7) being supported on a steel base frame (8) for storage of aggregates includes multiple feeder bins (9); an auxiliary conveyor (10) being equipped with VFD units positioned below the feeder unit (7) for receiving the weighed aggregates from the feeder bins (9); a collecting conveyor (11) for collecting the aggregates from the auxiliary conveyor (10); a slinger conveyor (12) supported through supporting means (19) for continuously supplying the aggregates from the collecting conveyor (11) to the inlet hopper (5) of the continuous mixer (3); a silo (13) of an adequate capacity for storage of cementitious ingredients; a weighing and conveyance system (14) supported through a steel structural frame (15) beside the continuous mixing unit (2) for weighing the cementitious ingredients received from the silo (13) and conveying the weighed cementitious ingredients to the inlet hopper (6) [shown in Fig.5] of the continuous mixer (3); a water feeding line (16) [shown in Fig.7] installed over the continuous mixing unit (2) having water spray nozzles for feeding water at the inlet of the continuous mixer (3) and a water metering system (17) [shown in Fig.7] installed on the water feeding line (16) for measuring the flow of water through the water feeding line (16); a load out conveyor (18) [shown in Fig. 8] fitted with supporting means (19) for delivering the mixed materials from the continuous mixer (3) to a gob hopper or a storage silo (20) having spaced opening for receiving the mixed materials and a hydraulic discharge gate (21) for discharging the mixed materials into a receiving truck (22) positioned below the gob hopper (20) or the storage silo (20); a control cabin (23) located approximately alongside the continuous mixing unit (2) comprises at least a single integrated control panel with PLC unit and VFD units for remotely monitoring and controlling the continuous mixing plant (1).
The detailed constructional view of the feeder unit (7) is shown in Fig. 3. Referring to Fig. 3, the feeder unit (7) comprises multiple feeder bins (9) having spaced inlet and discharge openings; a level sensor at discharge point for sensing the flow of aggregates from each feeder bin (9); and a load cell weighing bridge (not shown in figure) positioned at discharge end below the feeder unit (7) for continuously weighing the aggregates discharged on it. Further, the level sensors determine the presence of aggregates in the feeder bin (9) and send the signals to the control panel accordingly which shows zero when there is no aggregates in the feeder bin (9). Each feeder bin (9) is driven by VFD units for controlling and synchronizing the flow of aggregates according to the supply of water and cementitious ingredients into the continuous mixer (3).

Now referring to Figs. 4 and 5, the continuous mixing unit (2) comprises a pug-mill type twin shaft counter flow continuous mixer (3) equipped with couple of helibevel gearbox (24) and a motor (25) to drive the said continuous mixer (3); couple of spur gears (38) being fitted on the continuous mixer (3) for synchronizing the speed of gearbox (24) and motor (25). The twin shaft continuous mixer (3) according to the present invention comprises hinge type lockable covers (37) on the top thereof for easy maintenance and cleaning purpose. Both shafts of the continuous mixer (3) are well lubricated by automatic lubricating device which consists of plunger type grease pump at preset intervals. Further, the continuous mixer (3) is internally lined with Ni-hard adjustable liner tips (34), replaceable liner plates (39), and steel casting paddles (26) for minimum wearing and longer life of continuous mixing unit (2).

Now, as show in Fig. 6, the weighing and conveyance system (14) for cementitious ingredients comprises a weighing hopper (28) suspended with load cells (29) over the continuous mixer (3) for weighing of the cementitious ingredients received into the weighing hopper (28) from the silo (13) through a screw conveyor (30) positioned in inclined manner for conveying the cementitious ingredients from the silo (13) to the weighing hopper (28); a screw conveyor (30a) mounted with load cells (29a) below the weighing hopper (28) for conveying the weighed cementitious ingredients from the weighing hopper (28) into the inlet hopper (6) of the continuous mixer (3); a rotary valve (35) with VFD drive fitted at the bottom of the weighing hopper (28) for regulating the flow of cementitious ingredients from the weighing hopper (28).

Further, referring to Fig. 7, the water metering system (17) includes a non-contact type water flow meter (27) installed on the water feeding line (16) for indicating the flow of water passing through it and a water pump driven by VFD units for synchronizing the flow of water according to the flow of aggregates and cementitious ingredients into the continuous mixer (3).

A minimum and maximum preset value of weight in the weighing hopper (28) is fixed in PLC unit. The screw conveyor (30) feeds the cementitious ingredients to the weighing hopper (28) from the silo (13) until the maximum preset value of weight in the weighing hopper (28) is achieved and automatically stops when the maximum preset value of weight in weighing hopper (28) is achieved. The screw conveyor (30) again starts when the minimum preset value of the hopper (28) is achieved. Hence, the start and stop of this screw conveyor is totally automatic in accordance with the maximum and minimum preset value of the hopper (28). The screw conveyor (30a) is driven by the VFD unit which controls the quantity of cementitious ingredients to be conveyed to the continuous mixer (3). The quantity of cementitious ingredients is varied according to the requirement by the VFD unit. The screw conveyor (30a) is in synchronous with water and aggregates. When any component i.e. water and aggregates is varied, the rotary valve (35) automatically varies the supply of the cementitious ingredients to the continuous mixer (3) in that accordance.

As disclosed in Fig. 1 and 2, the control cabin (23) includes a control panel with VFD units for driving the feeder unit (7), the continuous mixing unit (2), the water pump and the screw conveyor (30a) and for synchronizing and controlling the flow of water, aggregates and cementitious ingredients into the continuous mixer (3); and a master pot on the control panel to increase or decrease the output of the plant (1). The control panel indicates the flow of aggregates from the feeder unit (7) in ton per hour, the flow of cementitious ingredients from the weighing hopper (28) in kilogram per hour and the flow of water from the water feeding line (16) in liter per minute.

Further, a platform (31) with an access ladder (32) and railings (33) are provided at the level of the continuous mixer (3), screw conveyors (30, 30a) and weighing hopper (28). An interlocking device is provided in the control panel so that an operation of the load out conveyor (18) is initiated before the start of the slinger conveyor (12) and collecting conveyor (11). The slinger conveyor (12) and the collecting conveyor (11) start only if the continuous mixing unit (2) is in running condition.

In continuous mixing operation in the continuous mixing plant (1) according to present invention, the feeder bin (9) continuously discharge the weighed aggregates onto the collecting conveyor (11) which continuously conveys the aggregates onto the slinger conveyor (12) then which deposits the aggregates into the inlet hopper (5) of the twin shaft continuous mixer (3). Further, the screw conveyor (30) also continuously supply the cementitious ingredients from the silo (13) to the weighing hopper (28) until the maximum preset value of weight is achieved in the weighing hopper (28). Then the weighed cementitious ingredients from the weighing hopper (28) are continuously discharged by rotary valve (35) to the screw conveyor (30a) which discharges cementitious ingredients into the inlet hopper (6) of the continuous mixer (3). This process is continuous as the weighed cementitious ingredients are discharged from the weighing hopper (28) into the inlet hopper (6) through the screw conveyor (30a). In addition, the spray nozzles fitted at the inlet of the continuous mixer (3) continuously supply the water through the water feeding line (16) into the continuous mixer (3) and the flow of water is measured by water flow meter (27) in liter per minute (LPM) which is indicated on the control panel. The continuous mixer (3) mixes the aggregates, cementitious ingredients and water during their flow from inlet to outlet of the continuous mixer (3) and discharges the mixed materials at the bottom of the continuous mixer (3) on the load out conveyor (18).

When the flow of aggregates from any feeder bin (9) is altered, the flow of water and cementitious ingredients also alters accordingly in PLC unit with the help of VFD units for synchronizing the flow of water, cementitious ingredients and aggregates for uninterrupted production of composite construction materials i.e. dry lean concrete, wet and dry mixed material, cement-concrete treated aggregate base material, blanketing material, granular sub base material, fine particles mixing like dry mortar, cement, fly ash and foundry sand.

The continuous mixing plant according to the present invention is economically viable which produces quality mixed materials in large quantity and can be used for multipurpose application which solves the problems of wet mix macadam plant, concrete batching plant and fine particles blending plant. Further, the said continuous mixing plant is very versatile, simple in structure and requires low investment which has the advantage of easy and fast installation and convenient maintenance with reduced maintenance cost and reduced life cycle cost.

The invention has been explained in relation to specific embodiment. It is inferred that the foregoing description is only illustrative of the present invention and it is not intended that the invention be limited or restrictive thereto. Many other specific embodiments of the present invention will be apparent to one skilled in the art from the foregoing disclosure. All substitution, alterations and modification of the present invention which come within the scope of the following claims are to which the present invention is readily susceptible without departing from the spirit of the invention. The scope of the invention should therefore be determined not with reference to the above description but should be determined with reference to appended claims along with full scope of equivalents to which such claims are entitled.