Claims:1. An induction sealing device for inductive sealing of opening of container traveling in a predetermined workflow direction, the induction sealing device comprising:
a housing;
an induction coil head disposed over the housing, the induction coil head comprising a plurality of spatially apart coil segments arranged in the workflow direction, wherein the plurality of coil segments comprising a first set of coil segments and a second set of coil segments, wherein the second set of coil segments are arranged between the first segments such that a center of each of the second set of coil segments is located at predefined distance from an axis connecting a center of each of the first set of coil segments; and
a plurality of field focusing elements disposed over each of the plurality of coil segments.
2. The induction sealing device as claimed in claim 1, wherein the induction sealing device comprises a control circuitry configured to allow flow of current in the coil segments of the coil head according to zero-voltage and zero-current-switching (ZVZCS) inverter topology.
3. The induction sealing device as claimed in claim 1, wherein the control circuitry comprises a transformer electrically coupled with the plurality of coil segments.
4. The induction sealing device as claimed in claim 1, wherein the plurality of field focusing elements are ferrite blocks.
5. The induction sealing device as claimed in claim 1, wherein the plurality of coil segments are electrically connected in series.
6. The induction sealing device as claimed in claim 1, wherein the induction coil head comprises a plurality of fiber blocks to integrate the corresponding field focusing elements with the corresponding coil segments, and wherein each of the plurality of fiber blocks comprises a plurality of arms extending towards from a center.
7. The induction sealing device as claimed in claim 1, wherein each of the plurality of coil segments is made of litz wire.
8. The induction sealing device as claimed in claim 1, at a particular Conveyor speed, wherein the current in each of the coil segments is constant and independent of load.
, Description:FIELD OF THE INVENTION
[0001] The present disclosure relates to induction sealing devices. More particularly, the present disclosure relates to an improved induction sealing device, provided with a multi-segmented coil to minimize and distribute the power loss. Multi-segmented coil head along with zero voltage zero current switching (ZVZCS) inverter topology facilitates reduction in power loss and ensures superior spatial distribution of the reduced power loss.

BACKGROUND OF THE INVENTION
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] Induction heating process is typically used for sealing plastic and glass containers for industries such as pharmaceutical, petroleum, food and beverage, etc. It is clean, energy efficient and does not need any start-up time, and also suitable for on-line and off-line applications. When a preconditioned container is brought within a predefined distance from the sealing head, a coil within the sealing head produces an electromagnetic field near the foil liner which is disposed within the cap. The electromagnetic flux produced by the field causes current to flow in the foil liner, which generates heat to seal the opening of the container with the foil liner, thus sealing the container.
[0004] Due to unavailability of litz-wire conductors, in the early days, the coil head used to be manufactured using copper pipes. In the initial days, to remove large high frequency power loss being produced due to skin and proximity effects taking place in coil head, water based cooling system was employed. However, as the power loss in copper-pipe based induction sealing heads was large, the water-cooling system became less efficient for complex coil arrangement. Subsequently, with easy availability of wide range litz-wire conductors, the transition from water-cooled to forced air-cooled model had started. Moreover, litz-wire based forced air-cooled versions made the process cleaner and energy efficient.
[0005] Gradually, several other application areas moved towards such induction sealing devices where the dimension of opening and its arrangement or location, foil sizes, etc. started becoming wide and complex. Two popular coil arrangements 101 and 102 are shown in FIGs. 1A and 1B. However, these arrangements are not applicable for a wide range of quality sealing mechanisms. In some cases, mechanical rotation arrangement of the coil head has been incorporated to ensure sealing of opening having large diameter. However, in such cases, the coil head should be rotated for each bottle size by a fixed angle. The process of rotation requires a lot of adjustments, which makes the process cumbersome.
[0006] In addition, there are some emerging applications such as nutraceutical, coffee, spices, etc. where, due to dust prone atmosphere prevailing around the controller. Similarly, dairy industry, etc. needs rigorous cleaning of the sealing equipment more frequently. Such applications need air and water tight induction sealing device.
[0007] There is, therefore, a need of an improved induction sealing device in the art, which overcomes above-mentioned and other limitations of existing approaches.
[0008] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.

OBJECTS OF THE INVENTION
[0009] Some of the objects of the present disclosure, which at least one embodiment herein satisfies are as listed herein below.
[0010] It is an object of the present disclosure to provide an improved sealing device applicable for a wide range of sealing applications such as glass and plastic containers.
[0011] It is an object of the present disclosure to provide an improved induction sealing device with minimized power losses in the coil head.
[0012] It is an object of the present disclosure to provide an improved induction sealing device with air tight and water tight enclosure.
[0013] It is an object of the present disclosure to provide an improved induction sealing device where the reduced power loss in the coil head is spatially distributed.
[0014] It is an object of the present disclosure to provide an improved induction sealing device with minimized power losses in the control circuitry.
[0015] It is an object of the present disclosure to provide an improved sealing device with spatial distribution of the reduced power loss in heat sink, thereby limiting the temperature rise inside the housing as well as in the heat sink, which eliminates the need of any cooling mechanism.
[0016] It is an object of the present disclosure to provide a system that is economical, reliable and generate zero defect sealing prospect.

SUMMARY
[0017] The present disclosure relates to induction sealing devices. More particularly, the present disclosure relates to an improved induction sealing device provided with multi-segmented coil to minimize power loss in the coil head. The spatial distribution of multi-segmented coil allows distribution of the reduced power loss spatially in each segment and the control circuitry to seal the opening of container at much lower coil current.
[0018] Additionally, the present disclosure also relates to combined effect of multi-segmented coil head, ZVZCS inverter topology and the transformer to reduce power loss in the control circuitry and in induction coil head. The ZVZCS inverter topology reduces the power loss in the control circuitry and distributes the incurred loss over a large number of components, thus avoiding prospect of any hotspot in housing.
[0019] An aspect of the present disclosure pertains to an induction sealing device for inductive sealing of openings of a container traveling in a predetermined workflow direction. The induction sealing device comprises a housing; an induction coil head disposed over the housing, the induction coil head comprising a plurality of spatially apart coil segments in the workflow direction, wherein the plurality of coil segments comprising a first set of coil segments and a second set of coil segments, wherein the second set of coil segments are arranged between the first segments such that a center of each of the second set of coil segments is located at predefined distance from an axis connecting a center of each of the first set of coil segments, and a plurality of field focusing elements disposed over each of the plurality of coil segments.
[0020] According to an embodiment, the plurality of field focusing elements are ferrite blocks.
[0021] According to an embodiment, wherein the plurality of coil segments are electrically connected in series.
[0022] According to an embodiment, the induction coil head comprises a plurality of fiber blocks to integrate the corresponding field focusing elements with the corresponding coil segments, wherein each of the plurality of fiber blocks comprises a plurality of arms extending towards from a center.
[0023] According to an embodiment, each of the plurality of coil segments is made of litz wire.
[0024] According to an embodiment, the induction sealing device comprises the heat sink for power converter stage. The inside air movement is created by buoyancy effect and it is good enough for the said design, it is unique.
[0025] the induction sealing device comprises a control circuitry configured to allow control of flow of current in the coil segments of the coil head according to zero-voltage and zero-current-switching (ZVZCS) inverter topology.
[0026] According to an embodiment, the control circuitry may include a transformer electrically coupled with the plurality of coil segments.
[0027] According to an embodiment, for a particular Conveyor speed, the current in each of the coil segments is constant and independent of load.
[0028] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS
[0029] The accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0030] FIGs. 1A and 1B illustrate exemplary representations of conventional induction coil heads of induction sealing devices.
[0031] FIGs. 2A and 2B illustrate exemplary representations of a front view and a side view of the proposed induction sealing device for inductive sealing of opening of container, respectively, in accordance with embodiments of the present disclosure.
[0032] FIG. 2C illustrates an exemplary representation of block diagram of top view of the proposed induction sealing device, in accordance with embodiments of the present disclosure.
[0033] FIGs. 3A and 3B illustrate exemplary representations of arrangements of four segmented coil and six segmented coil in the induction coil head, respectively, in accordance with embodiments of the present disclosure.
[0034] FIG. 3C illustrates an exemplary representation of inductance of coil segments based on spatial distribution of coil segments, in accordance with embodiments of the present disclosure.
[0035] FIGs. 4A and 4B illustrate exemplary representations of schematic diagrams of control circuitry of the induction sealing device according to zero-voltage and zero-current-switching (ZVZCS) inverter topology and zero voltage switching (ZVS) inverter topology, respectively, in accordance with embodiments of the present disclosure.
[0036] FIGs. 5A and 5B illustrate exemplary representations of heat sink arrangement according to ZVS and ZVZCS inverter topologies, respectively, in accordance with embodiments of the present disclosure.
[0037] FIG. 6 illustrates a graph showing transient and steady state temperature profile of heat sink and inside ambience, in accordance with embodiments of the present disclosure.

DETAILED DESCRIPTION
[0038] In the following description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present invention. It will be apparent to one skilled in the art that embodiments of the present invention may be practiced without some of these specific details.
[0039] Various methods described herein may be practiced by combining one or more machine-readable storage media containing the code according to the present invention with appropriate standard computer hardware to execute the code contained therein. An apparatus for practicing various embodiments of the present invention may involve one or more computers (or one or more processors within a single computer) and storage systems containing or having network access to computer program(s) coded in accordance with various methods described herein, and the method steps of the invention could be accomplished by modules, routines, subroutines, or subparts of a computer program product.
[0040] 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 disclosure 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).
[0041] Embodiments of the present disclosure relate to an induction sealing device that provides sealing to an opening of the container. The induction sealing device is operated at high frequency with zero ventilation. The sealing of the container consists of two operations – bonding of aluminum foil with lip/opening of container and removal of a substance e.g. wax from complete top surface of the foil. The substance holds the foil with directly to the cap or the cardboard kept inside the cap. Conventionally, the process of sealing is performed by both induction and thermal conduction, whereas the substance removal is predominantly performed by thermal conduction. The removal of the substance by thermal conduction makes the conventional process sluggish. The proposed induction sealing device is provided with an induction head comprising multiple coil segments located spatially in multiple axes. These multiple coil segments generate electromagnetic field more uniformly spatially to enable power transfer to the complete surface on thin metallic foil to enable both bonding and substance removal both predominantly by induction effect. The top surface of the foil has thin layer of wax and its bottom surface has polymer substance for bonding with the lip/opening of container. As the induction coil is multi-segmented and spatially distributed, the power is uniformly transferred to the foil. This mechanism allows transfer of the requisite amount of power for bonding of foil with the polymer as well as for wax removal. Due to spatial distribution of multi-segmented coil, the power transferred is distributed across surface of the foil, which do not allow the temperature rise of a particular area of the foil, thereby avoiding over burning of foil. In this manner, power transfer to the foil is uniformly distributed which ensures proper sealing.
[0042] FIGs. 2A and 2B illustrate exemplary representations of a front view and a side view of a proposed induction sealing device 100 for inductive sealing of lip/opening of container with the foil, respectively, in accordance with an embodiment of the present disclosure. As illustrated in FIG. 1, the device 100 may include a housing 1 and an induction coil head 24 disposed over the housing 1. The device may include a tower light 2, a conveyor mechanism 4, a foil sensor 5, a counter sensor 6, a jamm sensor 7, a height adjustment knob 8, sliding arrangement 9, a base 10, caster wheels 11, conveyor motor 12, display panel 25.
[0043] FIG. 2C illustrates an exemplary representation of the block diagram of top view of the proposed induction sealing device. As illustrated in FIG. 2C, the device may include a fuse 13, a line filter 14, a rotary switch 15, a power card 16, a choke 17, a control card 18, an auxiliary transformer 19, a terminal connector 20, a heat sink 21, and so on. In addition, the device also includes a control circuitry including capacitor bank, a main high-frequency transformer (interchangeably referred to as the transformer) whose secondary is electrically connected to the resonant tank circuit and primary is connected to output of ZVZCS inverter. In an embodiment, the induction sealing device is provided with an electronic housing/enclosure with ingress protection rating 65.
[0044] In an embodiment, the induction coil head 24 may include a plurality of coil segments spatially arranged in a workflow direction, where a plurality of field focusing elements may be disposed over each of the plurality of coil segments. In an example, diameter of each strand in the each of the coil segments is 0.1 mm. The plurality of coil segments may be electrically connected to the control circuitry to receive electrical power from the power supply. Specifically, the plurality of coil segments may be electrically connected to one or more tank circuits of the control circuitry. In an embodiment, the multiple series resonant circuits may be connected to a plurality of coil segments for sealing of wide area of the opening of the container. In an exemplary arrangement, the plurality of coil segments may be connected to resonant capacitor of the series resonant circuit at one end and secondary winding of the transformer at another end. The resonant capacitor may be connected to improve the power factor of the tank circuit to unity. Each segment of coil always draws a fixed amount of current.
[0045] When current flows through the coil segments of the induction coil head, an electromagnetic field is generated in a region of predefined range. The container is moved on a conveyor mechanism such as conveyor belt in a workflow direction to bring the container in the region of the predefined range of the electromagnetic field. The closed assembly of container consists of two elements – the cap carrying the foil at the top and the container. The foil resides inside the cap, where a layer of paraffine wax is attached to the top surface of foil to allow card board to hold the foil and the bottom surface of the foil has very thin layer of polymer e.g., lacquer. When foil is heated, the polymer helps bonding of foil with the lip of the container. The electromagnetic field directed towards the container, produces heat over the aluminum foil and melts the layer of polymer. The foil may then be removed from the cardboard when wax is evaporated over the top surface. The induction sealing device may be operated manually or in automatic mode, placing one container 3 at a time beneath the coil head 24, or it may be used to seal a number of containers 3 continuously or intermittently passing through the electromagnetic field under the coil head 24 on a conveyor belt or similar assembly line.
[0046] FIGs. 3A and 3B illustrate exemplary representations of arrangements of four segmented coil and six segmented coil in the induction coil head, respectively, in accordance with embodiments of the present disclosure. As illustrated in FIGs. 3A and 3B, the induction coil head may include a plurality of spatially apart coil segments 22 arranged in the workflow direction. The plurality of coil segments may include a first set of coil segments and a second set of coil segments. FIG. 3A illustrates the coil head with four segments 22-1, 22-2, 22-3, 22-4, whereas FIG. 3B illustrates the coil head with six coil segments 22-1, 22-2, 22-3, 22-4, 22-5, 22-6. As illustrated in FIG. 3A, the first set of coil segments may include coil segments 22-1 and 22-4, whereas the second set of coil segments may include coil segments 22-2 and 22-3. As illustrated in FIG. 3B, the first set of coil segments may include coil segments 22-1 and 22-6, whereas the second set of coil segments may include coil segments 22-2, 22-3, 22-4, and 22-5.
[0047] In an embodiment, the second set of coil segments 22-2 and 22-3 may be arranged between the first set of coil segments 22-1 and 22-6 (as shown in FIG. 3B) or 22-2, 22-3, 22-4, and 22-5 (as shown in FIG. 3B) such that a center of each of the second set of coil segments is located at predefined distance from an axis connecting a center of each of the first set of coil segments. In this manner, the coil segments may be placed on multiple axes in the coil head. As shown in FIG. 3A, coil segments 22-1 and 22-2 may be arranged on axis 1, whereas the coil segments 22-2 and 22-3 may be arranged on axis 2 and 3 respectively. In an exemplary embodiment, with an increase in number of coil segments, the number of axes on which the coil segments are arranged may also get increased. In some embodiments, the number of axes may remain the same with an increase in the number of coil segments as shown in FIG. 3B. The arrangement of coils segments on multiple axes may generate better power distribution on the sealing foil. It may also reduce time required for sealing the container because the removal of the layer of wax is now more dependent on induction effect, less on sluggish thermal conduction. Therefore, the distributed multi-segmented coil facilitates sealing of the container at reduced power distributed over much wider region of foil, which reduces any prospect of burning the hot spot zones on surface of the foil. In an example, the coil parameters may be, but not limited to, as follows:
L1: 32.2µH;
number of segment: 4;
coil current: 70A;
current density: 2.36A/mm2,
total surface area of coil: 1750 cm2 ;
whereas for illustration purpose, the specification of the device may be considered as
Power rating: 1.5 kw
Nominal frequency of ZVZCS inverter: 50 kHz
Conveyor speed: 11 meter per minute
Cap sizes (flat caps): 20mm – 120mm.
[0048] In an embodiment, the induction coil head may include a plurality of field focusing elements 23 disposed over each of the plurality of coil segments. The plurality of field focusing elements 23 may be ferrite slabs or blocks. The coil segments may be formed based on litz wire. In an embodiment, each ferrite core may be electrically isolated with other ferrite cores. Alternatively, an insulating material can be disposed between cores to electrically isolate them from each other. The coil head may also include a plurality of fiber blocks comprising a plurality of arms extending towards from a center which may coincide with the center of the corresponding coil segment. Each of the plurality of fiber blocks may be configured to integrate the corresponding field focusing elements with the coil segments. The field focusing element may have rectangular shape. However, it would be easily understood by a person of the ordinary skill in the art that any shape of the core can be utilized as long as it concentrates the magnetic field to a value sufficient to operate properly.
[0049] In an embodiment, the induction coil head may act as facilitator of energy transfer to the foil. The value of flux density in a particular coil segment induces proximity effect in the foil. The prospect of formation of hotspots may be much higher for single-segment coil configuration. The flux density created by turns of spiral coil segments may be peak at its center and may decrease with an increase in distance from the center. In the single-segmented coil, the magnitude of peak flux density may be much higher than each segment of multi-segmented coil. With the implementation of multi-segmented coils, the peak flux density may be distributed across centers of the multiple coil segments, which not only reduces the power loss in the coil drastically, but also eliminates the chance of formation of any hot spot in coil. It is very important factor for zero ventilated system.
[0050] In an embodiment, the coil segments may be kept energized at rated current value iL and at designed frequency fs (e.g. ˜50kHz). The foil may act a load for the induction sealing device. The loading on the coil segments of the coil head may vary from no load to full load. The induction coil head not only ensures sealing but also ensures reduced power loss in it. In the process of induction sealing, power POUT to the foil could be expressed as,
(1)
L1 is the combined inductance of all the coil segments in the induction coil head. The parameter kc depends on the coupling between the coil and sealing foil(s). Req represents the equivalent load impedance of foil(s) reflected to the coil segments.
[0051] FIG. 3C illustrates an exemplary representation of inductance of coil segments based on spatial distribution of coil segments, in accordance with embodiments of the present disclosure. As illustrated in FIG. 3C, the inductance L1, L2, L3, and L4 may correspond to coil segments 22-1, 22-2, 22-3, and 22-4, respectively, also shown in FIG. 3A. The combined inductance of L1, L2, L3 and L4 is represented as L5, also shown in above equation (1).
[0052] FIGs. 4A and 4B illustrate exemplary representations of schematic diagrams of control circuitry of the induction sealing device according to zero-voltage and zero-current-switching (ZVZCS) inverter topology and zero voltage switching (ZVS) inverter topology, respectively, in accordance with embodiments of the present disclosure. The power loss in coil head and the control circuitry may constitute more than 85% of total power loss in the induction sealing device. In order to achieve its reliable performance in water and air tight enclosure arrangement, the power loss inside the housing should be minimized and power loss should be distributed over a large number of components to avoid hot spots on any components in control circuitry e.g., transformer, tank circuit and the coil head. It may be achieved by an optimum co-ordination among the components of the control circuitry e.g., inverter, transformer, and a tank circuit. In a preferred embodiment, the specification of the inverter may be 1.5 kW, 50 kHz. As illustrated in FIGs. 4A and 4B, the combined inductance and resistance of the coil segments may be represented by L1 and rac, respectively, where Req is the load impedance offered by foil. In addition, the control circuitry may also include various inductances (LDC, L2), capacitors (C1, C2, C3, Cr, CDC), diodes (D1), switching devices (Q1, Q2, Q3) such as Mosfets, etc. The majority of the power loss occurs in induction coil head L1 and the power converter stage (loss in Q1-Q3, D1, L2, transformer).
[0053] In an embodiment, the transformer (TR) is used for isolation as well as to reduce the current level in the control circuitry to avoid any abnormal functioning of power components and avoid abnormal temperature rise in them. The current decreases at the primary side with an increase in turns ratio of the transformer. To achieve minimal losses in the transformer, current at the primary side and number of turns at secondary side should be minimum, which can be achieved when the value of turns ratio is maximum. The turn in primary of the transformer is determined by the input voltage to be applied and its frequency at primary of transformer.
[0054] In an embodiment, for a particular Conveyor speed, current iL through each of coil segments is kept constant under any load condition to ensure quality sealing of foils with wide range of diameter of opening of the container. To achieve maximum efficiency, a series resonant tank circuit is employed. To drive the series tank circuit for sealing wide range containers, either ZVS topology with phase angle control mechanism or ZVZCS topology may be used. For constant current in coil, the turns ratio of the transformer may be determined by a full load impedance of the tank circuit. In ZVZCS inverter topology, the value of the full load impedance is minimum, because it maintains the resonance condition. The ZVZCS inverter topology includes more power components compared to ZVS inverter topology (see Fig. 4A & 4B). But, the total power loss in ZVZCS inverter topology is reduced significantly compared to ZVS topology (as shown in Table 2). Moreover, the reduced power loss is distributed over more number of components (e.g. Q1, Q2, Q3, D1 and L2), which reduces thermal load not only on heat sink but also on each component. In an example, in case of full load, the steady state temperature rise of heat sink was only 16 deg C. Therefore, the ZVZCS inverter topology is more suitable for power and frequency control of the induction sealing device, because it is more efficient than the ZVS inverter topology. Table 1 and 2 shows the detailed comparison between the two topologies:
Inverter Topology ZVS Topology ZVZCS topology
Coil current, A 70 70
Impedance of loaded tank circuit, O 1.1 0.35
Turns ratio n of TR 4 (12:3) 6 (12:2)
Primary side current, A 17.5 11.67
Conduction loss in Q1/Q2 Yes, large Yes, small
Conduction loss in anti-parallel diodes Yes No
Turn on switching loss Nil Nil
Turn off switching loss Large Negligible
Recovery loss in anti-parallel diodes Large Negligible
Loss in C2 + C3, W Large Small
Loss in TR, W More Less
Loss in Q3, W Not applicable Small
Loss in D1 Not applicable Small
Loss in L2 Not applicable Small
total power loss and its distribution on heat sink The total loss in ZVS topology would be large, concentrated only on two devices Q1 and Q2. The prospect of hot spot is large. ZVZCS is superior for IP 65 enclosure, because there is no scope hot spot, in TR, coil L1, and power converter. The distribution of power loss is superior.

TABLE 1: IMPACT OF TOPOLOGY ON LOSS AND ITS DISTRIBUTION

Inverter Topology ZVS Topology ZVZCS topology
No load Full load No load Full load
Loss in Q1/Q2 (W) 37 35 11.0 12.0
Loss in C2 + C3, W 0.34 0.34 0.15 0.15
Loss in TR, W 12 12 7 10
Loss in Q3, W Not applicable 4 12
Loss in D1 Not applicable 12 3.4
Loss in L2 Not applicable 3.2 3
Total power loss, W 86.25 82.35 47.35 51.55

TABLE 2: PERFORMANCE COMPARISON
[0055] FIGs. 5A and 5B illustrate exemplary representations of heat sink arrangement 501 and 502 according to ZVS and ZVZCS inverter topologies, respectively, in accordance with embodiments of the present disclosure. As shown in FIG. 5A, in ZVS topology, the heat sink 501 may be coupled with components Q1 and Q2, whereas in ZVZCS topology, the heat sink is coupled with components Q1, Q2, Q3, and D1 as shown in FIG. 5B. In ZVZCS inverter topology, the losses are much less and distributed over a larger number of components compared to ZVS inverter topology. Therefore, the prospect of any hot spot in heat sink in ZVZCS inverter topology is drastically reduced when compared to ZVS inverter topology.
[0056] FIG. 6 illustrates a graph showing transient and steady state temperature profile of heat sink and inside ambience, in accordance with embodiments of the present disclosure. In an example, at 1.5 kW rated load, the steady state temperature of heat sink was 52.3 deg C and that of inside ambience was also 52.2 deg C where each component inside the enclosure would be safe. The equipment is, therefore, suitable for IP 65 enclosure. As shown in FIG. 6, over a time period, with reduced and spatially distributed power loss in induction coil head as well as in the control circuitry, temperature rise of the air inside the housing and in the heat sink, is well within acceptable limit.
[0057] While embodiments of the present invention have been illustrated and described, it will be clear that the invention is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents will be apparent to those skilled in the art, without departing from the spirit and scope of the invention, as described in the claim.
[0058] In the foregoing description, numerous details are set forth. It will be apparent, however, to one of ordinary skill in the art having the benefit of this disclosure, that the present disclosure can be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form, rather than in detail, to avoid obscuring the present invention.
[0059] While the foregoing describes various embodiments of the disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof. The disclosure is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the disclosure when combined with information and knowledge available to the person having ordinary skill in the art.

ADVANTAGES OF THE INVENTION
[0060] The present disclosure provides an improved induction sealing device with minimized power losses.
[0061] The present disclosure provides an improved sealing device that reduces power loss in each active and passive power component and the reduced power loss is spatially distributed to eliminate the need of any cooling mechanism.
[0062] The present disclosure provides an improved sealing device that includes an multi-segmented coil head to convert the sealing process from predominately thermal conduction dominant to induction heating one. This is a paradigm shift in cap sealing achieved through innovative coil head arrangement.
[0063] The present disclosure provides an improved sealing device applicable for wide range of sealing applications.
[0064] The present disclosure provides an improved sealing device that eliminates the need of water cooling mechanism and air cooling mechanism.
[0065] The present disclosure provides an induction sealing device that provides effective sealing of containers with the large foils, due to spatial distribution of the coil segments in the coil head.
[0066] The present disclosure provides an induction sealing device that provides uniform distribution of power across the surface of the foil, thereby avoiding over-burning of foil.
[0067] The present disclosure provides a system that is economical and reliable.