Description:Field of the invention:
The present invention generally relates to a precision weighing and dispensing of granular products, and more specifically the present invention relates to system combining a servo net scale (SNS) a and micro linear weigher (MLW) for precision weighing and dispensing of granular, free-flowing products such as coated seeds, rice, sugar, tea powder, agrochemicals, and similar materials, and a method for precision weighing and dispensing of granular products.
Background of the invention:
Precision weighing and dispensing of granular materials is crucial in many industries for ensuring accuracy, consistency, and compliance. Specialized scales and techniques are also employed to measure granular materials with high accuracy, often down to milligrams or even micrograms.
Generally, feeding units or apparatus are commonly employed to dispense granular, free-flowing products. These systems typically utilize either pneumatic or motorized gates to control the dispensing process. However, both pneumatic and motorized gate mechanisms lack the precision required for consistent dispensing, resulting in significant product giveaway during each cycle. To mitigate this issue, earlier systems incorporated a primary dispensing unit that operated using a two-phase approach, coarse and fine dispensing programmed into the control logic. Indian patent application 201821020269 discloses a granular material weighing apparatus wherein pair of cut gates fully open for bulk product discharge (coarse filling), when the filling cycle starts. After coarse filling, the pair of cut gates moves to 10-15 % opening for the fine filling using the multi position actuators. When target weight is reached, the pair of cut gates gets closed and the cycle repeats in the same order as above for the next filing. While this dual-phase method aimed to improve accuracy, limitations in gate control/ No control for every dispensing cycle continued to cause over dispensing and inefficiencies.
Another prior art patent US6502013 discloses a system for filling containers with a target weight of product. The system utilizes first and second weighing stages wherein the first stage includes first top cup or container having a first weighing device (load cell) and the second stage includes a second bottom cup having a second weighing device (load cell). A high-speed bulk feed subsystem supplies product to the top cup fills to its first setpoint. When the system controller recognizes that the top cup weight has reached the first setpoint, it pauses the bulk feed, discharges the top cup into the bottom cup, starts the dribble feed into the bottom cup, and starts the next cycle of bulk feed into the top cup. In US 6502013, limitations in gate control/ No control mechanisms result in inaccuracy and inconsistency in the amount of product dispensed. To improve accuracy, the dispensing speed needs to be reduced, which in turn increases the time required to complete a single dispensing cycle. This compromise leads to a reduction in the overall output capacity of the apparatus, typically measured in cycles per minute (CPM) or dumps per minute (DPM) with better accuracy.
Accordingly, there exists a need to addresses the challenges like speed and accuracy limitations faced by the prior art systems, by providing a system with a robust mechanical construction, exact repeatability and consistency ensuring, exact product flow/discharge; fast, accurate, and reliable weighing and dispensing in every cycle.
Summary of the invention
The present invention in one aspect, provides a system for precision weighing and dispensing of a target weight of granular, free flowing products. The system comprises a primary feeder, a vibratory feeder, a weighing unit, and a control unit in operable communication with the primary feeder, the vibratory feeder and the weighing unit. The weighing unit is having a weighing bucket mounted on a load cell for accurately weighing the granular product dispensed therein from the primary feeder and the vibratory feeder. The primary feeder is fitted with a feed gate for dispensing the granular product there through into the weighing bucket. A driving unit controls the initial opening of the feed gate to a first predefined position in a coarse cycle, partial closing of the feed gate to a second predefined position in a fine cycle and final closing of the feed gate. The vibratory feeder is configured to be actuated in the fine cycle for dispensing the granular product. The weighing bucket is provided with a pneumatically operated outlet for dispensing the target weight into a dump hopper. The weighing unit is configured for generating a first signal, a second signal and a third signal respectively when the first fraction, the second fraction and the target weight is received in the weighing bucket. a user interface is provided for communicating limits for the first predefined position of initial opening of the feed gate 7, the second predefined position of partial closing of the feed gate 7, the target weight, the first fraction of the target weight, and the second fraction of the target weight to the control unit. The control unit is a programmable logic controller that operates in tight coordination with the precision servo motors for feed gate opening and closing, based on real-time weight feedback from the load cell.
The coarse cycle is actuated by the control unit by actuating initial opening of the feed gate to the first predefined position. The load cell generates a first signal on receiving the first fraction of the target weight into the weighing bucket. On receiving the first signal, the control unit actuates the fine cycle. In the fine cycle, the feed gate is operated by the control unit to partially close to the second predefined position while the vibratory feeder is simultaneously activated for dispensing the product into the weighing bucket. The load cell generates a second signal on receiving the second fraction of the target weight into the weighing bucket. The control unit then actuates closing of the feed gate while dispensing through the vibratory feeder still goes on. The load cell generates a third signal on receiving the target weight into the weighing bucket. On receiving the third signal the control unit deactivates the vibratory feeder and actuates opening of the pneumatically operated outlet of the weighing bucket to dispense the target weight product into the dump hopper. The pneumatically operated outlet is closed once the target weight product is dispensed and the system is ready for the next weighing cycle. The first predefined position of the initial opening of the feed gate 7 is decided depending upon the granule size of the product and the weight required to be dispensed within the coarse cycle, while the second predefined position of partial closing of the feed gate is defined by 30% to 35% closure of the initial opening of the of feed gate.
The present invention in another aspect provides a method for precision weighing and dispensing of a target weight of free-flowing granular products. The method in an initial step involves receiving the granular product in a primary feeder. In the next step, the method involves initiating a coarse cycle by actuating opening of a feed gate of the primary feeder by the control unit to a first predefined position for dispensing a first fraction of the target weight into a weighing bucket mounted on a load cell. In the next step, a first signal is generated by the load cell when the first fraction of the target weight is received into the weighing bucket. On receiving the first signal, the control unit in the next step initiates a fine cycle, by partially closing the feed gate to a second predefined position, and simultaneously activating the vibratory feeder, for dispensing a second fraction of the target weight into the weighing bucket. A second signal is generated by the load cell when the second fraction of the target weight is received into the weighing bucket. In the next step, on receiving the second signal, the control unit closes the feed gate while continuing dispensing from the vibratory feeder. A third signal is generated by the load cell when the target weight is received into the weighing bucket. On receiving the third signal, the method involves deactivating the vibratory unit and actuating opening of a pneumatically operated outlet of the weighing bucket. In the final step, the pneumatically operated outlet is closed by the control unit to make the system ready for the next cycle.
Brief description of the drawings:
The embodiments can be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, the emphasis instead being placed upon illustrating the principles of the embodiments. Moreover, the figures, like reference numerals designate corresponding parts throughout the different views.
Reference will be made to embodiments of the invention, examples of which may be illustrated in the accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in the context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
The above and other objects, features, and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
Figure 1 illustrates schematic representation of front view of a system for precision weighing and dispensing of granular products with arrows showing the product flow, in accordance with an exemplary embodiment of the present invention;
Figure 2 illustrates schematic representation of a side view of a system for precision weighing and dispensing of granular products with arrows showing the product flow, in accordance with an exemplary embodiment of the present invention;
Figure 3A and 3B illustrate a schematic of weighing bucket of a system for precision weighing and dispensing of granular products, in accordance with an exemplary embodiment of the present invention;
Figure 4A and 4B illustrates a schematic of a drive unit of a feed gate of a system for precision weighing and dispensing of granular products, in accordance with an exemplary embodiment of the present invention; and
Figure 5 illustrates the graph of weight (measured in gram) of a product collected in the weighing bucket vs Time (measured in miliseconds) for three consecutive cycles, in accordance with an exemplary embodiment of the present invention.
Detailed description of the embodiments:
The present invention discloses a system and a method for precision weighing and dispensing of a target weight of granular products such as coated seeds, rice, sugar, tea powder, agrochemicals, and similar materials, by combining a servo net scale (SNS) a and micro linear weigher (MLW). The method provides rapid filling of containers or pouches with precise/ accurate weight.
The precision weighing system of the present invention is designed to overcome the speed limitations of current similar feeding systems and enhance the accuracy. Robust mechanical construction and exact repeatability and consistency of the system and the method of the present invention ensures exact product flow/discharge during every cycle. High precision components with low response time are preferred while designing the system to ensure fast, accurate, and reliable weighing and dispensing in every cycle.
In the following description, for the purpose of explanation, specific details are set forth in order to provide an understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without these details. One skilled in the art will recognize that embodiments of the present invention, some of which are described below, may be incorporated into a number of systems.
Throughout this application, with respect to all reasonable derivatives of such terms, and unless otherwise specified (and/or unless the particular context clearly dictates otherwise), each usage of:
“a” or “an” is meant to read as “at least one.”
“the” is meant to be read as “the at least one.”
References in the present invention to “one embodiment” or “an embodiment” mean that a particular feature, structure, characteristic, or function described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment.
Embodiments of the present invention include various steps, which will be described below. The steps may be performed by hardware components or may be embodied in machine-executable instructions, which may be used to cause a general-purpose or special purpose processor/controller programmed with the instructions or the logic circuit designed to perform the steps. Alternatively, steps may be performed by a combination of hardware, software, firmware and/or by human operators and the method steps of the invention could be accomplished by modules, routines, subroutines, or subparts of a computer program product.
If the specification states a component or feature "may' can", "could", or "might" be included or have a characteristic, that particular component or feature is not required to be included or have the characteristic.
As used in the description herein and throughout the claims that follow, the meaning of "a, an," and "the" includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of "in" includes "in" and "on" unless the context clearly dictates otherwise.
Exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. These embodiments are provided so that this invention will be thorough and complete and will fully convey the scope of the invention to those of ordinary skill in the art. Moreover, all statements herein reciting embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future (i.e., any elements developed that perform the same function, regardless of structure).
Hereinafter, embodiments will be described in detail. For clarity of the description, known constructions and functions will be omitted. Parts of the description may be presented in terms of operations performed by a mechanical and/or an Electrical/Electronic system, consistent with the manner commonly employed by those skilled in the art to convey the substance of their work to others skilled in the art. As is well understood by those skilled in the art, these quantities take the form of data stored/transferred in the form of electrical, magnetic, or optical signals capable of being stored, transferred, combined, and otherwise manipulated through mechanical and electrical components of the electromechanical systems; and the term electronic/electrical/computer system includes general purpose as well as special purpose data processing machines, switches, and the like, that are standalone, adjunct or embedded.
The present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in bracket in the following description and in the table below.
Table:
Ref No: Component Ref No: Component
1 Frame 15 Control panel
2 Lane hopper 16 Dump hopper
3 Level sensor 17 Pneumatic Panel.
4 Seal/ Gasket 18 Pneumatic Cylinder.
5 Primary feeder 19 Link.
6 Drive unit 20, 21 Mounting members of weighing Bucket.
7 Feed gate 22, 23 Hinges
8 Pipe feeder 24, 25 Flaps
9 Vibratory feeder 26 Weighing bucket mounts
10 Gate 27 Driven Unit
11 Dispensing track 28 Servo Motor and Gearbox.
12 Vibrator 29 Belt
13 Weighing bucket 30 Sensor and sensor mounting unit
14 Load cell
Referring to the figures 1 to 4, a system (100) precision weighing and dispensing of a target weight of granular products (hereinafter referred as “the system (100)”) in accordance with an exemplary embodiment of the present invention is shown. The system 100 comprises a primary feeder 5, a vibratory feeder 9, a weighing unit, and a control unit.
The system 100 is mounted in a fabricated frame 1 that provides a robust base for mounting of feeding units. A lane hopper 2 connected to an infeed line for receiving the granular product, is sealingly mounted at the top of the frame 1. The lane hopper 2 fitted creates a buffer for the primary feeder 5 and the vibratory feeder 9 with a level sensor 3 ensuring / maintaining level of product in the lane hopper 2 enabling uninterrupted operation during continuous production cycles. A seal/ gasket 4 serves as a sealing element between mating surfaces to prevent product leakage.
The primary feeder 5 serves as a secondary storage and facilitates movement of the granular product into the weighing unit using gravity. The primary feeder 5 is fitted with a feed gate 7 at a bottom end. The product flows by gravity from the primary feeder 5 into the weighing unit when the feed gate 7 opens. The feed gate 7 controls the product flow from the primary feeder 5 to the weighing unit. Referring to figures 4A and 4B, the drive unit 6 comprises of a precision motor 28, a gearbox 27 and a belt 29. The precision motor 28 is connected to the feed gate 7 through the gear box 27 and the belt 29. The precision motor 28 drives the feed gate 7 with help of the gear box 27 and the belt 29. A sensor 30 is mounted on the drive unit 6 to ensure the correct position of the feed gate 7 during every cycle.
The feed gate 7 is controllably operated by a driving unit 6 for actuating initial opening of the feed gate 7 to a first predefined position in a coarse cycle for dispensing a first fraction of the target weight, for actuating partial closing of the feed gate 7 to a second predefined position in a fine cycle for dispensing a second fraction of the target weight and for actuating final closing of the feed gate 7. The feed gate 7 is initially opened to a pre-defined position to dispense the majority of the target weight, referred to as the Coarse cycle. In an embodiment, the first predefined position of the initial opening of the feed gate 7 is decided depending upon the granule size of the product, shape of the granules of the product, and the weight of the granular product required to be dispensed within the coarse cycle. Subsequently, the feed gate is partially closed to reduce the flow rate, allowing for fine dispensing which is referred to as the fine cycle. In an embodiment, the feed gate 7 is partially closed to 30% to 35% of the initial opening, in the fine cycle. In other words, the second predefined position of partial closing of the feed gate 7 is defined by 30% to 35% closure of the initial opening of the of feed gate 7.
In an embodiment, the first fraction of the target weight dispensed from the primary feeder 5 during the coarse cycle contributes from 80% to 90% of the target weight, while the first fraction and the second fraction of the target weight dispensed from the primary feeder 5 respectively during the coarse cycle and the fine cycle collectively contributes up to 96% of the target weight. This staged approach enables to achieve most of the target weight (up to 96 %) with high repeatability and consistency.
The vibratory feeder 9 is configured to receive the granular product from the lane hopper 2 through a pipe feeder 8. The vibratory feeder 9 creates buffer for secondary dispensing unit. The vibratory feeder 9 is provided with a gate/ opening 10 at its base, and a dispensing unit including a horizontal tray 11 having one end mounted on a vibrator 12. The granular product is dispensed under gravity on the horizontal tray 11 through the gate 10. On actuation of the vibrator 12, the granular product on the horizontal tray 11 moves towards the other end of the horizontal tray 11 and dispenses into the weighing unit. The vibratory feeder 9 is configured to be actuated in the fine cycle for dispensing the granular product into the weighing unit.
The weighing unit is having a weighing bucket 13 mounted on a load cell 14 for accurately weighing the granular product dispensed therein from the primary feeder 5 and the secondary feeder 9. The weighing bucket 13 is having a pneumatically operated outlet for dispensing the target weight into a dump hopper 16. Referring to figure 3A and 3B, the pneumatically operated outlet of the weighing bucket 13 includes two hinged flaps 24 and 25 linked to a solenoid operable pneumatic cylinder 18. The flaps 24 and 25 are hinged at 22 and 23 and connected to the solenoid valve 18 through a link 19. 20, 21 and 26 are the mounts for mounting the weighing bucket 13.
The weighing unit is configured for generating a first signal, a second signal and a third signal respectively when the first fraction of the target weight is received in the weighing bucket 13, when the second fraction of the target weight is received in the weighing bucket 13 and when the target weight is received in the weighing bucket 13. In an embodiment, the first signal is generated when 80% to 90% of the target weight is dispensed in the weighing bucket, the second signal is generated when up to 96% of the target weight is dispensed in the weighing bucket and the third signal is generated when the target weight is dispensed in the weighing bucket.
The control unit is a PLC controller. The control unit is in operable communication with the driving unit 6 and the sensor 30 of the primary feeder, the vibrator 12 of the vibratory feeder, the solenoid valve of the pneumatically operated outlet of the weighing bucket and the load cell 14 of the weighing unit.
The control unit is configured for:
actuating the coarse cycle by actuating the initial opening of the feed gate 7 to a first predefined position,
actuating the fine cycle by simultaneous actuation of partial closing of the feed gate 7 to a second predefined position and activation of the vibrator, on receiving the first signal from the weighing unit,
actuating the final closing of the feed gate 7, on receiving the second signal from the weighing unit,
deactivating the vibrator and actuating opening of the pneumatically operated outlet of the weighing bucket 13, on receiving the third signal from the weighing unit to release the target weight of the product into a dump hopper 16, and
actuating closing of the pneumatically operated outlet of the weighing bucket 13, once the product is released.
Closing of the pneumatically operated outlet of the weighing bucket 13 completes one cycle and the system (100) is ready for the next cycle.
A user interface for communicating with the control unit is provided on a control panel 15. Limiting values for the first predefined position of initial opening of the feed gate 7, the second predefined position of partial closing of the feed gate 7, the target weight, the first fraction of the target weight, and the second fraction of the target weight are communicated to the control unit through the user interface, prior to start of a first cycle. The pneumatically operated weighing unit is finely tuned for both opening and closing timings, enabling rapid and accurate dumping operations. This design allows the apparatus to achieve a high number of dispensing actions, measured in cycles per minute (CPM). The system (100) is constructed in a single head or a multi-head configuration. In the single head configuration, the system (100) consists of a single primary feeder 5 with a single vibratory feeder 9 whereas in a double head configuration the system (100) consists of simultaneously operating two primary feeders 5 and two vibratory feeders 9.
In another aspect the present invention provides a method for precision weighing and dispensing of a target weight of granular products. The method is enabled through the system (100).
In a first step, the method involves receiving the granular product in a primary feeder 5 from the lane hopper 2.
In the next step, the method involves initiating a coarse cycle by actuating a driving unit 6 by a control unit, to open a feed gate 7 of the primary feeder 5 to a first predefined position of initial opening, for dispensing a first fraction of the target weight into a weighing bucket 13 mounted on a load cell 14 for accurately weighing the granular product dispensed therein. In an embodiment, the first fraction of the target weight contributes from 80% to 90% of the target weight. In an embodiment, the first predefined position of initial opening of the feed gate 7 is decided depending upon the granule size of the product and the first fraction of the target weight to be dispensed in the coarse cycle. In other words, the feed gate 7 is initially opened to a position based on the granule size of the product, shape of the granules and the weight required to be dispensed within the coarse cycle.
In the next step, the method involves generating a first signal by the load cell 14 when the first fraction of the target weight is received into the weighing bucket 13.
In the next step, the method involves receiving by the control unit, the first signal from the load cell 14 to initiate a fine cycle, by simultaneously actuating the driving unit 6 and a vibratory feeder 9, respectively for partially closing the feed gate 7 to a second predefined position, and for activating the vibratory feeder 9, for dispensing a second fraction of the target weight into the weighing bucket 13. In an embodiment, the second predefined position of partial closing of the feed gate 7 is defined by 30% to 35% closure of the initial opening of the feed gate 7. In other words, the feed gate 7 is partially closed to 30% to 35% of the initial opening, in the fine cycle.
In the next step, the method involves generating a second signal by the load cell 14 when the second fraction of the target weight is received into the weighing bucket 13.
In the next step, the method involves receiving by the control unit, a second signal from the load cell 14 to actuate the driving unit 6 for closing the feed gate 7. In an embodiment, the first fraction and the second fraction of the target weight dispensed from the primary feeder 5 respectively during the coarse cycle and the fine cycle collectively contributes up to 96% of the target weight.
In the next step, the method involves actuating the driving unit 6 by the control unit, to close the feed gate 7 on receiving the second signal from the weighing unit.
Further, the method involves generating a third signal by the load cell 14, when the target weight is received into the weighing bucket 13.
Next, the method involves receiving by the control unit, a third signal from the load cell 14 to deactivate the vibratory unit 9, and actuate opening of a pneumatically operated outlet of the weighing bucket 13.
In the final step, the method involves actuating by the control unit, closing of the pneumatically operated outlet of the weighing bucket 13.
In an embodiment, limits for the initial opening position of the feed gate 7, the partial closing position of the feed gate 7, the target weight, the first fraction of the target weight, and the second fraction of the target weight are set through a user interface and communicated to the control unit prior to start of a first cycle. In an embodiment the initial opening position and the partial closing position of the feed gate 7 is decided depending upon the granular size of the product, shape of the granules of the product, the target weight, and the weight of the granular product required to be dispensed within the coarse cycle and the fine cycle.
In an implementation, the driving unit 6 is actuated by the control unit to open the feed gate 7 to a first pre-defined position to dispense the first fraction of the target weight. The initial opening position of the feed gate 7 depends upon the granule size of the product and the weight required to be dispensed within the coarse cycle. This initial opening can be set up to a maximum of 85 mm. Once the first fraction of the target weight is dispensed in the weighing bucket 13, the load cell 14 generates a first signal. On receiving the first signal, the fine cycle is actuated wherein the control unit actuates partial closing of the feed gate 7 to 30% to 35% of the initial opening and simultaneously actuates the vibrator 12. The feed gate 7 partially closes to the second predefined position to reduce the flow rate allowing for fine dispensing referred to as the fine cycle. This staged approach enables the primary feeder 5 to achieve most of the target weight with high repeatability and consistency. The second signal is generated by the load cell 14, when up to 96 % of the target weight is dispensed in the weighing bucket. On receiving the second signal, the control unit actuates closing of the feed gate 7 and dispensing only through the vibratory feeder 9 is continued till the third signal is generated by the load cell 14 on reaching the target weight. Although in the fine cycle, second fraction (96 % of the target weight) is simultaneously dispensed from the primary feeder 5 and the vibratory feeder 9, the majority of the fraction is dispensed from the primary feeder 5. By the time the product starts dispensing from the vibratory feeder 9, the second fraction is almost dispensed from the primary feeder 5. On reaching the target weight, the control unit actuates the solenoid valve of the pneumatically operated outlet of the weighing bucket 13 to release the product into packaging/container (e.g., pouches or bags). On release of the product, the control unit actuates closing of the pneumatically operated outlet of the weighing bucket 13, and a cycle is completed. The system 100 is now ready for the next cycle.
The present invention is further described in the light of following experimental example which is set forth for illustration purpose only and not to be construed for limiting the scope of the disclosure.
Referring to Figure 5, a graph of Weight (gms) Vs. Time (msec) is shown for three feed cycles for 1000 gm target weight using the system (100) having a single head configuration. The primary feeder 5 begins dispensing the product at point A, marking the start of the coarse cycle. During this phase, material is rapidly discharged from the primary feeder 5, and the segment AB on the graph represents this high-speed dispensing operation.
primary feeder 5 begins dispensing the product at point A, marking the start of the coarse feed cycle. During this phase, material is rapidly discharged from the primary feeder 5, and the segment AB on the graph represents this high-speed dispensing operation.
Upon reaching point B, the coarse cycle concludes. At this stage, the servo-operated feed gate 7 partially closes, reducing the opening of the primary feeder 5 and allowing the fine feed cycle to begin. This phase, indicated by line BC on the graph, enables more precise control over the product flow from the primary feeder 5, allowing the system to approach the target weight more accurately.
During the fine feed cycle (BC), the vibratory feeder 9 also begins dispensing, assisting the primary feeder 5 in achieving tighter weight precision. At point C, the primary feeder 5 stops feeding, and the vibratory feeder 9 continues dispensing independently until point D. The segment CD on the graph represents the final feed cycle, handled exclusively by the vibratory feeder 9.
Once the final feed is complete at point D, the electronic load cell (14) which continuously monitors the product weight throughout the entire cycle from point A to point D confirms that the target weight has been reached. Upon confirmation, the controller sends a signal to the solenoid valve, for triggering the operation of the flaps 24 and 25, which are controlled by the pneumatic cylinder (18). This action allows the accurately weighed product to be discharged into the container or pouch via the dump hopper (16).
After dispensing, Flaps 24 and 25 automatically close. The opening and closing of these flaps occur within a predefined, optimized time interval, which is represented by the segment DA on the graph. Upon completion of this cycle, the system resets and is ready to begin the next feeding cycle.
The cycle duration is comprised of three principal phases:
 only a coarse/ bulk phase corresponding to segment AB on the graph = 0.62 Seconds;
 a bulk feed phase combined with dribble feed (from the vibratory feeder) corresponding to segment BC on the graph = 0.5 seconds; and
 only dribble feed phase (from the vibratory feeder) corresponding to segment CD on the graph = 0.25 seconds.
Dispensing of the product and closing of the bucket flaps to complete the cycle corresponds to segment DA of 0.5 seconds, on the graph.
For 1 kg packs, the system 100 achieves 25 to 27 weighments (cycles) per minute using a single-head configuration, depending on product size. The throughput of the system 100 doubles with two heads.
Filler System SKU (gms) Average Speed (Cycles per minute) Filling Accuracy
(Sigma 3)

System (100) with two heads 500 55~60 +/- (2-3) gms
1000 48~52 +/- (3-4) gms
2000 40~42 +/- (4-5) gms
5000 24~30 +/- (9-10) gms
The system 100 of the present invention ensures that no underweight or overweight packs/bags are delivered. The accurate dosing reduces product giveaway in terms of cost, thereby offering large savings in terms of cost for volume base filler. The system 100 of the present invention can be used for wide range of products such as granules, powder, seeds etc. any product with Free Flow property. A uniform product weight is delivered for all packages and the system 100 overcomes the speed and accuracy limitations of the current similar feeding systems in the current global market. The system and method of the present invention provides rapid filling of containers or pouches with precise/ accurate weight, thereby improving the overall output capacity, with better accuracy.
The foregoing description of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, and to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but such omissions and substitutions are intended to cover the application or implementation without departing from the scope of the claims of the present invention.
, Claims:We Claim
1. A system (100) for precision weighing and dispensing of a target weight of granular products, the system (100) comprising:
a primary feeder 5 configured for receiving the granular product, the primary feeder 5 fitted with a feed gate 7 at a bottom end thereof for dispensing the granular product there through, the feed gate 7 controllably operated by a driving unit 6 for actuating initial opening of the feed gate 7 to a first predefined position in a coarse cycle for dispensing a first fraction of the target weight, for actuating partial closing of the feed gate 7 to a second predefined position in a fine cycle for dispensing a second fraction of the target weight and for actuating final closing of the feed gate 7;
a vibratory feeder 9 configured to receive the granular product, the vibratory feeder 9 configured to be actuated in the fine cycle for dispensing the granular product;
a weighing unit, the weighing unit having a weighing bucket 13 mounted on a load cell 14 for accurately weighing the granular product dispensed therein from the primary feeder 5 and the secondary feeder 9, the weighing bucket 13 having a pneumatically operated outlet for dispensing the target weight into a dump hopper 16, the weighing unit configured for generating a first signal, a second signal and a third signal respectively when the first fraction of the target weight is received in the weighing bucket 13, when the second fraction of the target weight is received in the weighing bucket 13 and when the target weight is received in the weighing bucket 13; and
a control unit in operable communication with the driving unit 6, the vibratory feeder 9 and the weighing unit, the control unit configured for:
actuating the coarse cycle by actuating initial opening of the feed gate 7 to the first predefined position,
actuating the fine cycle by actuating partial closing of the feed gate 7 to the second predefined position and simultaneously actuating the vibrator, on receiving the first signal from the weighing unit,
actuating the final closing of the feed gate 7, on receiving the second signal from the weighing unit,
deactivating the vibratory feeder 9, and actuating opening of the pneumatically operated outlet of the weighing bucket 13, on receiving the third signal from the weighing unit and
actuating closing of the pneumatically operated outlet of the weighing bucket 13.
2. The system (100) as claimed in claim 1, wherein the first predefined position of the initial opening of the feed gate 7 is decided based on the granule size of the product and the weight required to be dispensed within the coarse cycle.
3. The system (100) as claimed in claim 1, wherein the second predefined position of partial closing of the feed gate 7 is defined by 30% to 35% closure of the initial opening of the feed gate 7.
4. The system (100) as claimed in claim 1, wherein the first fraction of the target weight contributes from 80% to 90% of the target weight.
5. The system (100) as claimed in claim 1, wherein the first fraction and the second fraction of the target weight dispensed from the primary feeder 5 respectively during the coarse cycle and the fine cycle collectively contributes up to 96% of the target weight.
6. The system (100) as claimed in claim 1, wherein the primary feeder 5 and the vibratory feeder 9 receive the granular product from a lane hopper 2 provided with a sensor for continuously monitoring a product level in the lane hopper 2.
7. The system (100) as claimed in claim 1, wherein the pneumatically operated outlet of the weighing bucket 13 includes two hinged flaps 24 and 25 linked to a solenoid operable pneumatic cylinder 18.
8. The system (100) as claimed in claim 1, wherein the control unit is a PLC controller.
9. The system (100) as claimed in claim 1, wherein a user interface is provided for communicating limits for the first predefined position of initial opening of the feed gate 7, the second predefined position of partial closing of the feed gate 7, the target weight, the first fraction of the target weight, and the second fraction of the target weight to the control unit
10. A method for precision weighing and dispensing of a target weight of granular products, the method comprising the steps of:
receiving the granular product in a primary feeder 5,
initiating a coarse cycle by actuating a driving unit 6 by a control unit, to open a feed gate 7 of the primary feeder 5 to a first predefined position for dispensing a first fraction of the target weight into a weighing bucket 13 mounted on a load cell 14 for accurately weighing the granular product dispensed therein;
generating a first signal by the load cell 14 when the first fraction of the target weight is received into the weighing bucket 13;
receiving by the control unit, the first signal from the load cell 14 to initiate a fine cycle, by simultaneously actuating the driving unit 6 and a vibratory feeder 9, respectively for partially closing the feed gate 7 to a second predefined position, and for activating the vibratory feeder 9, for dispensing a second fraction of the target weight into the weighing bucket 13;
generating a second signal by the load cell 14 when the second fraction of the target weight is received into the weighing bucket 13;
receiving by the control unit, the second signal from the load cell 14 to actuate the driving unit 6 for closing the feed gate 7;
generating a third signal by the load cell 14, when the target weight is received into the weighing bucket 13;
receiving by the control unit, a third signal from the load cell 14 to deactivate the vibratory unit, and actuate opening of a pneumatically operated outlet of the weighing bucket 13; and
actuating by the control unit, closing of the pneumatically operated outlet of the weighing bucket 13 to complete a cycle.
11. The method as claimed in claim 10, wherein l limits for the first predefined position of initial opening of the feed gate 7, the second predefined position of partial closing of the feed gate 7, the target weight, the first fraction of the target weight, and the second fraction of the target weight are communicated to the control unit through a user interface, prior to start of a first cycle.
12. The method as claimed in claim 10, wherein the first predefined position of initial opening of the feed gate 7 is decided depending upon the granule size of the product and the first fraction of the target weight to be dispensed in the coarse cycle.
13. The method as claimed in claim 10, wherein the second predefined position of partial closing of the feed gate 7 is defined by 30% to 35% closure of the initial opening of the feed gate 7.
14. The method as claimed in claim 10, wherein the first fraction of the target weight contributes from 80% to 90% of the target weight.
15. The method as claimed in claim 10, wherein the first fraction and the second fraction of the target weight dispensed from the primary feeder 5 respectively during the coarse cycle and the fine cycle collectively contributes up to 96% of the target weight.
16. The method as claimed in claim 10, wherein the granular product is received in the primary feeder 5 and the vibratory feeder 9 from a lane hopper 2 provided with a sensor for continuously monitoring a product level in the lane hopper 2.
17. The method as claimed in claim 10, wherein the pneumatically operated outlet of the weighing bucket 13 includes two hinged flaps 24 and 25 linked to a solenoid operable pneumatic cylinder 18.
18. The method as claimed in claim 10, wherein the control unit is a PLC controller.