FORM 2
THE PATENT ACT 1970
(39 OF 1970)
&
The Patent Rules, 2003
COMPLETE SPECIFICATION
(See Section 10 and Rule 13)
1 TITLE OF THE INVENTION:
AN OVERLOAD INSENSITIVE ENERGY EFFICIENT NOVEL COIL HEAD FOR AUTOMATED INDUCTION CAP SEALING SYSTEM OF CYLINDRICAL AND TAPERED WIDE-MOUTHED CONTAINER
2 APPLICANT (S)
Name: ELECTRONICS DEVICES WORLDWIDE PRIVATE LIMITED
Nationality: INDIAN COMPANY
Address: Unit 22; Mistry Industrial Complex, Cross Road “A”; MIDC
Andheri East, Mumbai- 400093
3 PREAMBLE TO THE DESCRIPTION
COMPLETE
The following specification particularly describes the invention and the manner in which it is
to be performed.

TITLE
[0001] An overload insensitive energy efficient novel coil head for automated induction cap sealing system of cylindrical and tapered wide-mouthed container.
FIELD OF INVENTION
[0002] The present invention relates to Overload Insensitive energy-efficient novel coil-head for automated sealing of cylindrical and tapered wide- mouth containers which is capable of sealing container mouth of diameter ranging within 40mm to 140 mm.
BACKGROUND OF INVENTION
[0003] Sealing container with metallic/ aluminium foil is long in demand in order to avoid leakage or spillage during transportation and also to prevent tampering and thereby adulteration of the packaged products. Using the controlled transferred energy in contactless manner to aluminium foil by high-frequency electromagnetic induction principle, the easily automated induction cap sealing process is being used to seal plastic containers such as drums and bucket to achieve the stated objective. This coil head can be used for sealing glass containers as well but usually glass container of such a wide diameter cap is not used for packaging. Initially, only pharma and petroleum industries used induction cap sealing process. Now the process is increasingly being used as a packaging solution for diverse products, example in pharmaceutical products, petroleum, food and beverage items, etc. The coil head or coil structure is the heart of this coil assemblies and of the process thereof.
[0004] When used in Pharma industry, the range of diameter of foils (35 – 60 mm) was not large. The coil head used to be water-cooled which were gradually replaced by Litz-wire based air-cooled versions as shown in Figure 3a. With these coils of Figure 3a, the magnetic field B closer to the centre of spiral coil or close to the conveyor axis of square coil was more, accordingly the distribution of transferred power on the foil was non-uniform. SO sealing with this coils resulted in uneven heating of foil surface, particularly when the foils
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are large. The impact of heating was more on foil area around the conveyor axis and less at periphery perpendicular to conveyor axis. This unequal heating resulted under-sealing in some zone, burning or overheating in some areas. The quality issues were more for large foils as shown in Figure 3b.
[0005] Gradually, several other application areas started adopting induction cap sealing where the cap dimension and its arrangement or location, foil sizes, etc. started becoming wide and complex, and either of coil arrangements of Figure 3a was not equipped to ensure quality sealing for wide-mouth containers, and needed frequent process adjustment. Hence, the process setting was cumbersome, and lead to energy inefficient solution. When foils of larger diameters, for example >75 mm, were used, coils of Figure 3a showed following sealing issues:
i. Proper sealing was not possible for containers using large size foils; ii. Overheating/burning was noticed on foil area around the conveyor axis; iii. Under-sealing or less heating was noticed on foil areas at the periphery of minor axis; iv. It needed extensive quality inspection, therefore, reduced productivity and increase the cost.
[0006] To resolve the quality issues listed above for sealing of wide–mouth containers, a coil head was introduced as shown in Figure 4a. It consisted of four identical spiral coil segments placed in different axes with the aim to distribute the transferred energy on foils more evenly so that under-sealing, over-heating of foil or the problem of wax removal from foils of large diameter would be eliminated. It resolved the sealing issues completely for circular foils of diameter in the range 20-120 mm. It needed 2.0 kW power converter and the coil head helped distribute the loading POUT on moving foil spatially. It avoided over burning or under-sealing and resulted zero-defect sealing. The lateral benefits were too many. Compared to results obtained by coil heads of Figure 3a, power converter using the coil head of Figure 4a consumed less power (2.0 kW), when compared with the converter using traditional coil of Figure 3a (2.6 kW), and increased the productivity significantly.
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Moreover, efforts needed for quality inspection were minimized. Efficiency of coil of Figure 4a is evident from Figure 4b where various cylindrical container of varied wide-mouth diameter was sealed efficiently.
[0007] To widen the application potential of induction cap sealing process, two more coil heads were introduced as shown in Figure 5a and Figure 6a. The coil of Figure 5a not only yielded quality sealing of circular foils of wider range, it successfully sealed containers using square as well as rectangular foils as shown in Figure 5b. On the other hand, the coil head of Figure 6a could seal plastic drums and buckets having cap diameter around 200 mm as shown in Figure 6b. The coil is capable of sealing large containers, where only one foil should be beneath the power converter.
[0008] The process of induction sealing continues to suffer from two basic types of quality issues under-sealing and burning or overheating of foils in some segments. This induction cap sealing works on open-loop, does not have any feedback to check the sealing quality, no real-time corrective measures is possible. In normal circumstances, these problems are related to the energy distribution on foil surface. It could also happen when the converter is overloaded. The prospect of overload depends on the area of foil area residing beneath the coil head. This over-load is also possible when large size cylindrical and tapered containers (body dia. ≥ foil diameter) are fed on the conveyor one after the other without any gap in between. If the container is large but the foil diameter is small, then the chance of the converter getting overloaded is less. The prospect of overload of container arrangement as shown in Figure 7 (large containers where cap diameter is less than the body diameter) is less than that of Figure 8 (large containers where cap diameter is equal to the body of the diameter). Ideally there should not be any restrictions in the feeding process.
[0009] In overload condition, the value of Req crosses the boundary value where the value of iL starts falling. It means that increase in load (Req) would reduce the value of iL as shown in Figure 9.
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[0010] When the quantum of power transfer POUT to foils is reduced, it causes quality defects, like, under sealing, etc. (undersealing shown in Figure 3b). One way to avoid the overload condition is to increase the power capacity of the converter, which is possible either by decreasing the value of turns-ratio n:1 or increasing the value of input DC voltage Vdc.
[0011] Thus there is a need for a solution to replace a large power converter for sealing multiple cylindrical and tapered wide-mouth containers by a power source of much smaller rating and ensure not only improvement in quality of sealing but also increase the productivity. Further there is a need to cater wider application range (dia.: 40-140 mm), including perfect sealing of large-diameter pure-cylindrical and tapered containers (body diameter ≥ foil diameter) where there is no constraint on the number of containers residing beneath the converter.
SUMMARY OF INVENTION
[0012] The process of induction cap sealing suffers from two basic types of quality issues under-sealing and burning or overheating of foils in some segments. It could also happen when the converter is overloaded. The prospect of overload depends on the area of foil area residing beneath the coil head. This over-load is also possible when large size cylindrical and tapered containers (body diameter ≥ foil diameter) are fed on the conveyor one after the other without any gap in between. If the container is large but the foil diameter is small, then the chance of the converter getting overloaded is less. In overload condition, the value of Req crosses the boundary value where the value of iL starts falling. It means that increase in load (Req) would reduce the value of iL.
[0013] When the quantum of power transfer POUT to foils is reduced, it causes quality defects, like, under sealing, etc. (undersealing shown in Figure 3b). One way to avoid the overload condition is to increase the power capacity of the converter, which is possible either by decreasing the value of turns-ratio n:1 or increasing the value of input DC voltage Vdc. Thus there is a need for a solution to replace a large power converter for sealing multiple
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wide-mouth cylindrical and tapered containers by a power source of much smaller rating and ensure not only improvement in quality of sealing but also increase the productivity.
[0014] The present invention discloses an overload Insensitive energy-efficient novel coil-head for automated sealing of wide-mouth cylindrical tapered containers novel induction coil head that not only can avoid any over-load situation, it does perform quality sealing consuming much less power thereby the power rating of the converter is reduced.
[0015] The novel coil head comprise a multi-geometrically configured concentric turns of coil positioned on a single coil segment, arranged along a planar surface wherein an axis of the planar surface coincides with a conveyor axis in the direction of the movement of the conveyor belt, wherein a planar spiral shaped inner turns of coil is first arranged in the single coil segment followed by a concentric planar spiral square shaped outer turns of coil configured around the periphery of the circular shaped inner turns of coil, operatively connected to a power converter circuit. The novel multi-geometric construction of the novel coil-head ensures desired foil-diameter specific energy distribution on foil surface to avoid any under-sealing and/or over-heating of any part of the container lid. The construction of the coil segments is such that the mutual inductance between the coil and foils that effectively controls the quantum of energy transfer is not allowed to increase to a large value, it avoids saturation of the power controller.
BRIEF DESCRIPTION OF DRAWINGS
Figure 1: A typical power converter circuit for induction cap sealing system
Figure 2: No load and full load waveforms of 2 kW, 50 kHz power controller for
sealing containers of 20-120 mm cap diameter when the coil current was set at 120A –
Waveform Fig 2a and 2b.
Figure 3a: Induction sealing heads traditionally used in induction cap sealing process
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Figure 3b: Typical sealing defects (e.g., under-sealing at one corner while burning of foil in
some other segments, etc.) while sealing with large foil diameters.
Figure 4a: EDWPL’s novel coil head for sealing wide range containers using circular foils
Range: 20-120mm.
Figure 4b: Perfectly sealed wide range containers (foil diameter: 20 – 120 mm).
Figure 5a: Patented coil (IN 425208) for sealing of wide range containers using foils of
different geometry.
Figure 5b: Actual capability demonstration of the coil in Figure 5a.
Figure 6a: Innovative coil for sealing drum, bucket and wide-mouth containers.
Figure 6b: Demonstration of quality sealing of drum, bucket with large foil.
Figure 7: Large containers where cap diameter is less than the body diameter
Figure 8: Large containers including tapered container where cap diameter is equal to or
greater to the body diameter
Figure 9: Demonstration of current profile when several large cylindrical and tapered
containers reside beneath the multi-segmented coil head
Figure 10: The geometry, winding pattern and flux concentrators of the proposed coil head.
Figure 11: The actual bare coil head.
Figure 12: Actual coil head with flux concentrators placed on top.
Figure 13: Complete experimental set up of the 50 kHz power converter.
Figure 14: No-load and loaded waveforms of the power controller when the coil
current was set at 65 A to successfully seal multiple cylindrical and tapered containers of
foil diameter 135 mm.
Figure 15: Demonstration of current profile when several large cylindrical and tapered
containers reside beneath the proposed coil head.
Figure 16. Demonstration of the proposed coil head for sealing of large cylindrical and
tapered containers (Fig 16a. diameter ≤140 mm) fed onto the conveyor back to back and
sealing result (Fig 16b).
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DETAILED DESCRIPTION OF INVENTION
[0016] The present disclosure is best understood with reference to the detailed figures and description set forth herein. Various embodiments have been discussed with reference to the figures. However, those skilled in the art will readily appreciate that the detailed descriptions provided herein with respect to the figures are merely for explanatory purposes, as the methods and systems may extend beyond the described embodiments. For instance, the teachings presented and the needs of a particular application may yield multiple alternative and suitable approaches to implement the functionality of any detail described herein. Therefore, any approach may extend beyond certain implementation choices in the following embodiments.
[0016] References to “one embodiment,” “at least one embodiment,” “an embodiment,” “one example,” “an example,” “for example,” and so on indicate that the embodiment(s) or example(s) may include a particular feature, structure, characteristic, property, element, or limitation but that not every embodiment or example necessarily includes that particular feature, structure, characteristic, property, element, or limitation. Further, repeated use of the phrase “in an embodiment” does not necessarily refer to the same embodiment.
[0017] The process of induction sealing continues to suffer from two basic types of quality issues under-sealing and burning or overheating of foils in some segments. This induction cap sealing works on open-loop, does not have any feedback to check the sealing quality, no real-time corrective measures is possible. In normal circumstances, these problems are related to the energy distribution on foil surface. It could also happen when the converter is overloaded. The prospect of overload depends on the area of foil area residing beneath the coil head. This over-load is also possible when large size cylindrical and tapered containers (body diameter ≥ foil diameter) are fed on the conveyor one after the other without any gap in between. If the container is large but the foil diameter is small, then the chance of the converter getting overloaded is less. The prospect of overload of container arrangement as shown in Figure 7 (large containers where cap diameter is less than the
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body diameter) is less than that of Figure 8 (large containers where cap diameter is equal to the body of the diameter). Ideally there should not be any restrictions in the feeding process.
[0018] In overload condition, the value of Req crosses the boundary value where the value of iL starts falling. It means that increase in load (Req) would reduce the value of iL as shown in Figure 9.
[0019] When the quantum of power transfer POUT to foils is reduced, it causes quality defects, like, under sealing, etc. (undersealing shown in Figure 3b). One way to avoid the overload condition is to increase the power capacity of the converter, which is possible either by decreasing the value of turns-ratio n:1 or increasing the value of input DC voltage Vdc. Thus there is a need for a solution to replace a large power converter for sealing multiple wide-mouth cylindrical and tapered containers by a power source of much smaller rating and ensure not only improvement in quality of sealing but also increase the productivity. Further there is a need to cater wider application range (dia.: 40-140 mm), including perfect sealing of large-diameter pure-cylindrical containers (body diameter ≥ foil diameter) where there is no constraint on the number of containers residing beneath the converter.
[0020] High-frequency moderate-power (≤3 kW, 40-80 kHz) induction heating controller is used for cap sealing applications [1]-[3]. By using a desired coil head, the controller is designed to yield zero defect sealing with high productivity, and it should be energy efficient. A typical power circuit for induction cap sealing system, based on series resonant topology, for cap sealing applications is shown in Figure 1 [1], [4]. It consists of a coil L1 used for transferring power to a metallic object, here it is aluminium (Al) foil; a half-bridge inverter (consisting of IGBT Q2, Q3, C2 and C3) for feeding high frequency ac current to coil L1 as well as for tracking of resonant frequency �r = ^=, Cr is the tank capacitor. A buck-chopper (consisting of IGBT Q1, fast diode D1 and inductor L2) is used for power control. When the inverter operates at resonant frequency, the tank-circuit (L1-Cr) load appears resistive. In continuous-duty induction sealing the coil head is kept in energized condition.
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When containers travel below the coil head, the power is transferred to each Aluminium foil by electromagnetic induction. The transferred power is used to seal plastic and glass containers. The tank circuit (L1-Cr) is laid in series configuration. Phased lock loop (PLL) is used to track the resonant frequency fr and an error in power or current is used for power control. PWM chopper plus PLL together ensures the inverter switches Q2 and Q3 turn on at zero voltage and turn-off at near zero current (ZVZCS) operation. The high frequency loss of the inverter is negligible and, due to the absence of any circulating current, the conduction loss is minimum. Two waveforms under extreme loading conditions (no-load and full-load) of a 2 kW induction cap sealer are shown in Figure 2.
[0021] The ZVZCS topology minimizes the power loss in each component of the controller. With help from optimal performance from the coil head, the energy efficiency of the system could be maximum at any resonant frequency.
[0022] The parameters of the power converter for sealing containers using wide range cap diameter (20-120 mm) are listed below:
[0023] The total power POUT transferred to foils depends on four parameters,
�OUT = �c�i�l�s = �l�eq ………….. (1) L1 is inductance of unloaded coil head, iL is the RMS current through it, fs is the inverter frequency and the parameter Kc depends on coupling between the coil and foil(s).
Req represents the total load resistance of foil(s) reflected to the tank circuit.
[0024] When the coil is loaded, the effective inductance is reduced to Leq. Expressions of Req and Leq are,
�eq= fM^ and, �eq = �i- fM2R2ff (2)
Kfoil+a,sLfoil
fifoil+ll, Lfoil
Lfoil is foil inductance and Rfoil is its resistance, M is the mutual inductance between the coil and foil and �s = 2��s.
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[0025] The resonant frequency feq of the loaded tank circuit is,
�eq=W= (3)
[0026] For half-bridge inverter, the expression of chopper voltage VCH (see Figure 1) is,
�CH = 1.57��eq�L (4)
Where n: 1 is the turns ratio of the transformer. The maximum value of VCH is the DC input voltage Vdc. Vdc is derived after rectification and filtering of single-phase Mains input AC voltage.
[0027] The loading of power source is decided by the foil geometry such as thickness and diameter of the foil and the mutual inductance M (2). Under Zero Voltage Zero Current switching condition, the load to the power converter is represented by Req (4) , like,
�eq=°^ (5)
[0028] The value of Req depends on the value of Rfoil and M (2). M depends on the area of foil below the coil head and also the distance between it and the foil [4]. Rfoil depends on the path length of eddy current in it. Therefore, both M and Rfoil depend on diameter of the foil.
[0029] From the converter perspectives, the loading �OUT = �£�eq is decided by the coil current and the area of foil(s) residing beneath the coil head.
[0030] At a particular value of iL, the upper limit of loading is decided by the limiting condition of (5),
�eq(max)≤^c (6)
[0031] The performance of resonant power converter under over-load condition is complex. During overload, the value of iL is reduced as shown in Figure 9. It results reduction in POUT
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causing under-sealing in some segments (shown in Figure 3b) of the container. The chance of overload is less for a container whose body diameter is less than that of foil (See Figure 7). The worst case loading takes place when several wide-mouth perfectly cylindrical and tapered containers (Foil diameter ≥ body diameter) residing beneath the power converter while sealing as shown in Figure 8. Therefore, the number of containers nc could reside beneath the coil head is decided by the relation,
�c�eq ≤ �eq (max) ≤ ^p^ (7)
Therefore, conventionally, to seal containers shown in Figure 8, either VCH should be increased or the value of turns ratio n:1 should be decreased. In either case, the power rating of the controller would be increased; it involves the design of a different high-power converter.
[0032] The present invention discloses an overload Insensitive energy-efficient Novel coil-head for automated sealing of wide-mouth cylindrical and tapered containers novel induction coil head that not only can avoid any over-load situation, it does perform quality sealing consuming much less power thereby the power rating of the converter is reduced.
[0033] In a preferred embodiment, the coil head comprise a multi-geometrically configured concentric turns of coil positioned on a single coil segment, arranged along a planar surface wherein an axis of the planar surface coincides with a conveyor axis in the direction of the movement of the conveyor belt, wherein a planar spiral circular shaped inner turns of coil is first arranged in the single coil segment followed by a concentric square shaped outer turns of coil configured around the periphery of the circular shaped inner turns of coil, operatively connected to a power converter circuit.
[0034] In another preferred embodiment, the novel coil-head is uniquely designed, consists of a single coil segment where the turns are wound in different geometric configuration to ensure desired foil-diameter specific energy distribution on foil surface to avoid any under-sealing and/or over-heating of any part of the container lid. The construction of the coil
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segments is such that the mutual inductance between the coil and foils that effectively controls the quantum of energy transfer is not allowed to increase to a large value, it avoids saturation of the power controller.
[0035] In one other embodiment, the sealing of small containers and the major part of large container lip around the axis of conveyor movement is taken care of by a circular spiral coil. Again to have near uniform heating over a wider zone by the circular spiral coil, the inner diameter of the spiral coil is kept large. The magnetic field at the centre is nearly flat, generating a trapezoidal field profile. For sealing of either side of the lip periphery perpendicular to the conveyor axis is achieved by having a few outer turns laid square, it increases the travel time beneath the coil head.
[0036] In an embodiment, the coil of the preferred embodiment is equipped to seal much wider range of containers cylindrical shape i.e. the diameter of the main body is equal to that of the foil of diameter 40-140 mm.
[0037] In another embodiment, the coil head distributes the transferred energy in such a manner that it is utilized by the foil in a superior manner. The disclosed induction coil head for high-speed sealing of large cylindrical and tapered containers (foil diameter = body diameter) is shown in Figure 10. It consists of single coil segment, but possesses multiple geometrical configurations. For sealing of small diameter foils (diameter ≥45 - 60 mm) the inner segment of the coil is designed like a circular spiral type. It also takes care of sealing of large-diameter foils around the conveyor axis. To ensure sealing around the periphery perpendicular to the conveyor axis, one square shaped coil-segment has been wound. The side of the square is large enough to transfer sufficient power around the periphery. The travel time of the foil-segment perpendicular to the conveyor axis under the coil-segment is significantly increased. The disclosed novel one coil segment is sufficient to seal wide range cylindrical and tapered containers of diameter between 40-140 mm.
[0038] In another preferred embodiment, the remaining space beneath the power converter is dummy, devoid of any coil segment, so though there are several large size cylindrical and
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tapered containers beneath the converter, only one would reside beneath the coil head, while other containers beneath the power source do not load the power source at all. In this manner, the new coil avoids any overload like situation.
[0039] Figure 11 shows the actual coil when the ferrite slabs as flux concentrator are not added. The area of litz wire based coil is 22.6 mm2, and for a 50 kHz operation, the diameter of each strand is 0.1 mm.
[0040] Figure 12 shows the actual coil head where the feerite slabs have been added. The complete power converter assembly including the proposed coil head is shown in Figure 13. Wavforms under no-load and full-load conditions are shown in Figure 14a and 14b respectively. Figure 15 shows the waveform of profile of current iL and primary voltage of transformer when there were 4 number 135 mm dia perfectly cylindrical and tapered containers resided beneath the power converter. It is clear from Figure 15 that there was no dip in value of iL. Therefore, sealing quality would not be affected. The successfully sealed containers are shown in Figure 16.
[0041] The disclosed novel coil head not only increases the productivity of the process, it consumes less power, the converter design is simplified. The coil is driven by a series resonant inverter assisted by a power control circuit to achieve near resonant frequency operation.
[0042] In an embodiment, the novel coil head perfectly seals large perfectly cylindrical and tapered containers (body diameter is equal to foil diameter) with cap diameter up to 135 mm, and also seals containers using foil diameter ranging from 40 mm till 140 mm, that is, throughout wide range diameter.
[0043] The present invention makes the sealing process of large cylindrical and tapered containers easier and the containers touching one another could be fed on the conveyor, that is, no feeding restrictions. Due to superior power transfer by the coil and its optimal
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utilization by the foil, the power rating of the converter is reduced. The length of costly litz wire conductor is reduced, thereby the cost of the converter is reduced. The coil head could be used for wide range applications.
Table: 1: Parametric comparison with the existing art/ prior art of Fig 4a. power converter

Control mode Cap sealer with multi-segmented coil Cap sealer with proposed coil:
single-segment with multiple
geometric configuration
Sealing range 20-120 mm 40-140 mm foil
Sealing speed with
largest container or
foil 14 meter/min. for sealing 120
mm foil
(coil current: 120 A) 20 meter/min. for sealing 135
mm foil
(coil current: 80 A)
Sealing under overload Sealing quality gets affected, current dips Sealing quality not affected; overload-insensitive
Turns ratio transformer 10:2 10:2
Mains current when
the coil is not
loaded, A 2.0 (wastage is more) 0.75 (wastage is much less)
Chopper voltage
when the coil is not
loaded, V 40.5 25.2
Chopper voltage when the coil is fully loaded, V 300 (3 no. 120 mm foils
resided below the converter),
overloaded; poor sealing 265 (when 3 number 133 mm
foils resided beneath the
converter); perfect sealing
Vdc, V 310 310
Nominal coil current
iL, A 120 80
Coil inductance L1, μH 18.0 26.5
Tank capacitor Cr, μF 0.564 0.422
Litz wire conductor of L1 Strands: 3780; strand dia.: 0.1mm Strands: 2880; strand: 0.1mm
Resonant frequency fs, kHz 50.3 47.8
Converter topology Zero-voltage zero-current switched inverter for frequency control and buck converter for power control
Q1, Q2, Q3+D1 MMG75S060B6TC MMG75S060B6TC
POUT, kW 1.75 kW 1.1 kW

Tests and Trial Reports

Table – 2
Parameter Values and Specifications



[0044] Thus the novel coil head of the present invention provides following benefits:
i. efficiently seals wide mouth perfectly cylindrical and tapered containers (foil
diameter ≤140 mm),
ii. the large diameter foil would not overload the power converter;
iii. free from saturation effect, quality issues of sealing would be avoided; iv. ensures temper-proof quality sealing of large cylindrical and tapered containers
using wide range foils;
v. this coil avoids overload condition even if several large cylindrical and tapered
containers reside on the conveyor beneath the converter; because of the novel
coil head design; vi. Effective energy efficient sealing by a single coil segment has reduced the power
rating of the controller; vii. Effective energy utilization by a multi-geometrically configured single coil
segment has significantly reduced the power loss in the coil head;

viii. the single coil segment consumes lesser amount of costly litz wire, thereby, the
cost as well as weight of the coil head are reduced; ix. the process setting for sealing of bulk material is eased, the large cylindrical and
tapered containers could be fed back-to-back, no restriction on gap between two
consecutive containers;
x. with help of requisite automation system, would achieve high productivity in the
production process; xi. widen the application potential of environment-friendly energy-efficient induction
cap sealing process; xii. with help of unique field distribution, this invention achieves the desired sealing
quality caps using lesser energy consumed, making the process energy-efficient.

WE CLAIM:
1. An overload insensitive energy efficient novel coil head [1000] for automated induction cap sealing system of cylindrical and tapered wide-mouthed container [700, 800] , comprising a multi-geometrically configured concentric turns of coil positioned on a single coil segment, arranged along a planar surface wherein an axis of the planar surface coincides with a conveyor axis [1610] in the direction of the movement of the conveyor belt, wherein a spiral circular [1020] shaped inner turns of coil is first arranged in the single coil segment followed by a concentric spiral square [1010] shaped outer turns of coil configured around the periphery of the circular shaped inner turns of coil, operatively connected to a power converter circuit.
2. The overload insensitive energy efficient novel coil head [1000] for automated induction cap sealing system of cylindrical and tapered wide-mouthed container [700, 800] as claimed in claim 1, wherein the inner diameter of the spiral circular shaped [1020] inner turns of coil is kept large at 60mm, and the outer diameter of the spiral circular shaped inner turns of coil is 155 mm.
3. The overload insensitive energy efficient novel coil head [1000] for automated induction cap sealing system of cylindrical and tapered wide-mouth container [700, 800] as claimed in claim 1, wherein the length of the spiral square [1010] shaped outer turns of coil is ranging between 240 mm to 260 mm.
4. The overload insensitive energy efficient novel coil head [1000] for automated induction cap sealing system of cylindrical and tapered wide-mouthed container [700, 800] as claimed in claim 1, comprising the multi-geometrically configured concentric turns of coil positioned on a single coil segment as claimed in claim 1, have a complex trapezoidal magnetic field profile created by a planner spiral coil inside and square planner coil outside, they are series connected.
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5. The overload insensitive energy efficient novel coil head [1000] for automated induction cap sealing system of cylindrical and tapered wide-mouthed container [700, 800] as claimed in claim 1, wherein the inner planar spiral coil seals the lip of the container around the conveyor axis; and wherein the square coil [1010] seals the lip of the container around the periphery perpendicular to the conveyor axis [1610] on either side of the conveyor axis.
6. The overload insensitive energy efficient novel coil head [1000] for automated induction cap sealing system of cylindrical and tapered wide-mouthed container [700, 800] as claimed in claim 1, wherein the wide-mouthed container diameter ranges between 40 mm to 140 mm (wide range foil diameter) and the container may be of plastic or of glass.
7. The overload insensitive energy efficient novel coil head [1000] for automated induction cap sealing system of cylindrical and tapered wide-mouthed container [700, 800] as claimed in claim 1, wherein the constructional feature of the multi-geometrically configured concentric turns of coil positioned on a single coil segment controls the mutual inductance between the coil and the foil, which controls the quantum of energy transfer preventing the saturation of the power controller.
8. The overload Insensitive energy efficient novel coil head [1000] for automated induction cap sealing system of cylindrical and tapered wide-mouth container [700, 800] as claimed in claim 1, wherein both side [1030A, 1030B] of the single coil segment beneath the converter have empty space devoid of any coil ensuring only one wide mouth container will reside beneath the novel coil head avoiding over¬loading the power source.

9. The overload insensitive energy efficient novel coil head [1000] for automated induction cap sealing system [1300] of cylindrical and tapered wide-mouth container, as claimed in claim 1, wherein the system is capable of sealing wide mouth container at much higher speed and creating large empty space beneath the converter where there is no power transfer, therefore any further loading is avoided.
10. The overload insensitive energy efficient novel coil head [1000] for automated induction cap sealing system of cylindrical and tapered wide-mouth container wide-mouthed container [700, 800] as claimed in claim 1, wherein the power converter circuit comprising zero voltage zero current (by tracking the resonant frequency of the resonant tank series resonant tank circuit and power control) switched inverter for frequency control, and buck-chopper circuit for power control, coil inductance (L1) is 26.5 μH, Tank capacitor (Cr) is 0.422μF, Litz wire conductor of coil inductance is 0.1 mm with 2880 strands, and resonant frequency is 47.6 kHz.