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:
A NOVEL ENERGY EFFICIENT COIL HEAD FOR AUTOMATED SEALING OF
PLASTIC DRUMS AND BUCKETS
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.
Page 1 of 20

TITLE
[0001] A novel energy efficient coil head for automated sealing of plastic drums and buckets.
FIELD OF INVENTION
[0002] The present invention relates to a novel energy-efficient coil head for automated
sealing of plastic drums and buckets (also wide mouth container) wherein these plastic
drums and buckets are having a wide of diameter of cap/ closure through induction heating
sealing application.
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. 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] Initially, only pharma and petroleum industries used induction cap sealing process.
The range of diameter of foils was not large and was typically within the range of 35 – 60
mm caps, identified as small diameters. For such small diameters, the coil assemblies of
Fig. 4a were good enough to ensure sealing of those bottles, where the coil used was either
a circular spiral or rectangular. Typical distribution of field flux density B beneath each coil
of Fig. 4a is shown in Fig. 4b. The magnetic field B closer to the centre of spiral coil or close
Page 2 of 20

to the conveyor axis of rectangular coil is more. Therefore, the distribution of transferred
power on the foil wound not be uniform. It would result in uneven heating of foil surface.
The impact of heating would be more on foil area around the conveyor axis and less heating
would be there at periphery perpendicular to conveyor axis. There would be unequal heating,
it could result under sealing in some zone, burning or overheating in some areas. In the coil
assemblies of Figure 4a, the removal of wax (used to create a bond between the foil and
cardboard / EP backing) removal from top surface would be a problem lowering the quality
of seal even more. These issue of unequal heating and wax removal made the coil
assemblies of Figure 4a inapplicable for large range diameter.
[0005] With time the demand become wide and complex with large cap of varied dimension,
and its arrangement or location, foil sizes, etc. for various purposes and the coil
arrangement / assemblies as disclosed in Figure 4a no longer able to meet the demand of
wide range quality sealing. It needed frequent process adjustment. The process setting
could be cumbersome, and that could lead to energy inefficient solution. When foils of larger
diameters (>75 mm) were used, coils assemblies of Figure 4a showed sealing issues, some
of which are:
i. Proper sealing was not possible for containers using large size foils (>75 mm dia.);
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. Wax removal from the centre of large foil was not successful;
v. It needed extensive quality inspection, for critical applications and high-speed
production process, it was costly;
vi. problems of sealing issues of large-cap containers could not be resolved just by
increasing the quantum of power transferred to foils.
Page 3 of 20

[0006] To resolve the issues of the coil assemblies of Figure 4a, this applicant earlier had
introduced a novel coil head/ assemblies which consisted of four identical spiral coil
segments placed in different axes as shown in Figure 5. The aim was 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 successfully
resolved sealing issues completely using circular foils of diameter in the range 20-120 mm.
It needed 2.0 kW power converter (parameters listed above). The coil head helped distribute
POUT on moving foil spatially. It avoided over burning or under-sealing and resulted zerodefect sealing. The lateral benefits were too many. Compared to results obtained by coil
heads of Figure 4a, this innovative approach consumed less power (2.0 kW), when
compared with traditional controllers, and increased productivity significantly; efforts
needed for quality inspection were minimized. But this too had a shortcoming as it was
suitable for circular foils. A demonstration of wide range of sealing using coil head/
assemblies of Figure 5 is shown in Figure 6.
[0007] To address this shortcoming, applicant had further introduced a novel coil assembly
as shown in Figure 7a which enhanced the quality sealing of circular foils of wider range,
and also successfully sealed containers using square as well as rectangular foils as shown
in Figure 7b. This coil assembly / head is patented under IN 425208. However, the range of
cap diameters continued to be within 20mm to 120mm.
[0008] Due to the emerging need of bulk packing of edible oil and fats, speciality chemicals
and adhesives, container sealing with wider cap diameter (≤ 200 mm) is in demand. There
is a need for coil assembly/ head suitable for sealing containers using large foil of diameter
range of 130-200 mm.
Page 4 of 20

SUMMARY OF INVENTION
[0009] The present invention discloses novel energy-efficient coil-head for automated
sealing of plastic drums and buckets (also wide mouth container) which ensure temperproof sealing used for packing edible oil and fats, speciality chemicals, etc. where the
diameter of cap typically ranges between 80mm to 200mm.
[0010] The present invention discloses coil assembly/ head using three coil segments where
in each one with a specific purpose to achieve the desired energy distribution on foil surface
to avoid any under-sealing and/or over-heating of any part of the container lid. This
construction and placement of three coil segments are 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.
[0011] The disclosed three coil segment comprising a circular coil and two rectangular coils,
wherein the circular coil seals the major part of each container lip around the axis of
conveyer movement. To have near uniform heating over a wider zone by the spiral coil, the
inner diameter is kept large. The magnetic field at the centre is nearly flat, generating a
trapezoidal field profile.
[0012] The sealing of one side of the lip periphery perpendicular to the conveyor axis is
achieved by a rectangular coil while the sealing of other side of the lip periphery
perpendicular to the conveyor axis is achieved by another rectangular coil. All the three coil
segments are connected in series.
[0013] This novel coil assembly/ head is driven by a series resonant inverter assisted by a
power control circuit to achieve near resonant frequency operation.
Page 5 of 20

[0014] The power control circuit with predefined parameters are supplies electrical power
to the energize the coils for achieving the sealing objective.
[0015] The present invention with help of automated process achieves high productivity in
the production process. It widens the application potential of environment-friendly energyefficient induction cap sealing process, and achieves sealing of plastic drum and buckets
(also wide mouth container) having large diameter caps using lesser energy consumed,
making the process energy-efficient.
BRIEF DESCRIPTION OF DRAWINGS
[0016] Figure 1: Schematic diagram of a typical power controller circuit for an induction
cap sealing system.
[0017] Figure 2a: Waveforms of inverter and corresponding gate signals while delivering
70A current coil through the coil, when, the coil is not loaded.
[0018] Figure 2b: Waveforms of inverter and corresponding gate signals while delivering
70A current coil through the coil, when two 120 mm dia. foils were placed beneath the coil
heads of Figure 7a.
[0019] Figure 3: ZVZCS-based converter and an optimized coil could optimize the energy
efficiency around any resonant frequency
[0020] Figure 4a: Traditional coil structures for induction sealing,
[0021] Figure 4b: Typical distribution of normalized flux density below the coil along the
conveyer axis, (b is the width of rectangular coil and r is the radius of spiral coil)
[0022] Figure 5 novel coil head for sealing of wide range containers using circular foils
(Range: 20-120mm).
[0023] Figure 6: Demonstration of wide range sealing using circular foils of diameter ranging
from 20 mm to 120mm.
[0024] Figure 7a: Patented coil (IN 425208) for sealing of wide range containers using foils
of different geometry.
Page 6 of 20

[0025] Figure 7b: Actual demonstration of capability of the coil. [Rating of the power
controller: 2.0 kW].
[0026] Figure 8a: Drum with cap dia.: 200 mm.
[0027] Figure 8b: Bucket with cap dia.: 185 mm, and container with cap dia.: 140 mm.
[0028] Figure 9: Quality issue: Under-sealing at the periphery perpendicular to the
conveyor axis (Foil diameter is 130 mm).
[0029] Figure 10: Dimensions of the proposed coil head for sealing of containers using
large diameter cap (Cap diameter is between 140mm – 200 mm)
[0030] Figure 11: Magnetic field distribution in two circular coils having different inner radius
and same outer radius.
[0031] Figure 12: The proposed coil head manufactured as per dimensions of Figure 10, top
of it is filled with ferrite cores acting as field concentrators for sealing of plastic buckets and
drums (Cap dia. range: 140-200 mm).
[0032] Figure 13: Complete experimental set up of the 42 kHz, 1.6 kW power controller for
induction cap sealing.
[0033] Figure 14a: ZVZCS waveforms of the power inverter at 70A coil current, when, the
coil is not loaded.
[0034] Figure 14b ZVZCS waveforms of the power inverter at 70A coil current, when
containers using foil diameter of 190 mm were placed beneath the coil head.
[0035] Figure 15: 42 kHz, 1.6 kW power controller for induction cap sealing.
[0036] Figure 16: Demonstration of wide range sealing using the proposed coil head of
Figure 12.
DETAILED DESCRIPTION OF INVENTION
[0037] 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
Page 7 of 20

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.
[0038] 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.
[0039] Figure 1 shows a schematic diagram of a typical power controller circuit for an
induction cap sealing system.
[0040] Figure 2 discloses a NO LOAD and FULL LOAD waveforms of 2kW, 45 kHz power
controller for sealing containers of 20mm to 120mm cap diameter when the coil current is
set at 70A. Figure 2a is the waveforms of inverter and corresponding gate signals while
delivering 70A current coil through the coil, when, the coil is not loaded. Figure 2b is the
waveforms of inverter and corresponding gate signals while delivering 70A current coil
through the coil, when two 120 mm dia. foils were placed beneath the coil heads of Figure
7a.
[0041] Figure 3 shows the importance of ZVZCS-based power converter and an optimized
coil on energy efficiency around any desired resonant frequency.
[0042] Figure 4 shows a typical induction coil heads traditionally used in induction coil head
and the corresponding field profile beneath the coil head. Figure 4a shows a traditional coil
Page 8 of 20

structures for induction sealing. Figure 4b is a typical distribution of normalized flux density
below the coil along the conveyer axis, (b is the width of rectangular coil and r is the radius
of spiral coil)
[0043] Figure 5 shows applicant’s previously disclosed novel coil head for sealing of wide
range containers using circular foils (Range: 20-120mm).
[0044] Figure 6 demonstrate wide range sealing using circular foils of diameter ranging from
20 mm to 120mm using coil assembly/ head of figure 5.
[0045] Figure 7a shows applicant’s already patented coil (IN 425208) for sealing of wide
range containers using foils of different geometry; and Figure 7b: Actual demonstration of
capability of the coil. [Rating of the power controller: 2.0 kW].
[0046] Figure 8a is the sample of a drum of cap diameter 200mm;
[0047] Figure 8b is a sample bucket with cap diameter of 185mm.
[0048] Figure 8c is a sample container of cap diameter 140 mm.
[0049] Figure 9 demonstrate typical problem of under sealing at the periphery perpendicular
to the conveyor axis where the Foil diameter is 130 mm.
[0050] Figure 10 is the schematic diagram of present novel coil assembly/ head for sealing
of containers using large diameter cap (Cap diameter is between 140mm – 200 mm)
[0055] Figure 11 is the Magnetic field distribution in two circular coils having different inner
radius and same outer radius.
[0056] Figure 12 is the novel coil assembly/ head for sealing of wide range containers for
packing of bulk material where the Foil diameter range is between 130mm-190mm. Physical
representation of the novel coil assembly/ head manufactured as per dimensions of Figure
10, top of it is filled with ferrite cores acting as field concentrators for sealing of plastic
buckets (including wide mouth container) and drums (Cap dia. range: 140-200 mm).
[0057] Figure 13 discloses the complete experimental set up of the 42 kHz, 1.6 kW power
controller for induction cap sealing.
[0058] Figure 14 is No-load and loaded waveforms of the power controller when the coil
current was set at 60 A to successfully seal containers using foil diameter of 190 mm. Figure
Page 9 of 20

14a is ZVZCS waveforms of the power inverter at 70A coil current, when, the coil is not
loaded.
[0059] Figure 14b is ZVZCS waveforms of the power inverter at 70A coil current, when
containers using foil diameter of 190 mm were placed beneath the coil head.
[0060] Figure 15 is a 42 kHz, 1.6 kW power controller for induction cap sealing. Outside of
the machine [17] with Display Panel [12] and Resonant Capacitor [14]
[0061] Figure 16 demonstrate wide range of foil diameter ranging between 130mm to
190mm sealed bottles using the proposed coil head.
[0062] The present invention discloses a novel energy-efficient coil-head [1200] for
automated sealing of plastic drums and buckets (including wide mouth container) through
induction heating (cap sealing). Induction cap sealing is an ideal method for providing
temper-evidence packaging solutions of glass [4] or plastic containers [5]. It transfers
requisite energy in contactless manner and its start/stop time is negligible. The discloses
process is automated to yield high speed productivity with zero defect in sealing. It is
energy-efficient, environment friendly process. The present novel energy coil head/
assembly widens the application potential of induction cap sealing process addressing the
need of sealing cap of wider diameter (≤200 mm) preferably between 80mm to 190mm.
[0063] High-frequency moderate-power (≤3 kW, 40-80 kHz) induction heating controller is
used for cap sealing applications. Using a desired coil head, the controller is designed to
yield zero defect sealing with high productivity and it should be energy efficient. Schematic
diagram of a typical induction heating system used for cap sealing applications is shown in
Figure 1. 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 fr. A buckchopper (consisting of IGBT Q1, fast diode D1 and smoothing inductor L2) is used for power
control. The resonant or tank capacitor Cr is used to reduce the value of load impedance
Page 10 of 20

and increase the load power factor of the power transfer circuit i.e., the tank-circuit L1-Cr.
When the inverter operates at resonant frequency, the tank-circuit load appears resistive.
In continuous-duty induction sealing the coil head is kept in energized condition. When
containers travel below the coil head, the power is transferred to each Aluminium foil [6] 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 𝑓୰ୀ
ଵ
ଶగඥ௅భ஼౨
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 also reduced. Two waveforms under extreme loading conditions of a
2 kW induction cap sealer are shown in Figure 2. The parameters of the power converter for
sealing containers using wide range cap diameter (20-120 mm) of the coil assembly shown
in Figure 7a are listed below:
Component Value
Coil inductance L1: 30.5 μH
Resonant capacitor Cr [14]: 0.565 μF
Coil current: 70 A
Resonant frequency: 39 kHz.
Turns ratio of TR: 14:2
Primary conductor area and
strand size
5.65 sq. mm and 0.1mm
secondary conductor area and
strand size
22.6 sq. mm and 0.1mm
Q1, Q2, Q3+D1: SKM75GB063D
Chopper inductance L2: 1.5 mH, 15A
Inverter topology: Zero voltage zero current
switching (ZVZCS).
Full load current drawn from the
240 V AC Mains:
8.3 A
Power rating of the controller: 2.0 kW.
Page 11 of 20

[0064] The ZVZCS topology minimizes the power loss in each component of the controller.
[0065] With help from optimal performance from the coil head, the energy efficiency of the
system could be maximum at any resonant frequency as shown in Figure 3.
[0066] The total power POUT transferred to foils depends on four parameters,
𝑃OUT = 𝐾௖𝐿ଵ
𝑖௅
ଶ𝑓௦ = 𝑖௅
ଶ𝑅௘௤ ……………. (1)
L1 is inductance of unloaded coil head, iL is current through it, fs is the inverter frequency
i.e., the frequency of current iL 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.
When the coil is loaded, the effective inductance is reduced to Leq. Expressions of Req and
Leq are,
𝑅eq =
ఠೞ
మெమோfoil
ோfoil
మ ାఠೞ
మ௅foil
మ
and, 𝐿ୣ୯ = 𝐿ଵ −
ఠమெమோ౜౥౟ౢ
ோ౜౥౟ౢ
మ ାఠమ௅౜౥౟ౢ
మ
……………… (2)
Lfoil is foil inductance and Rfoil is its resistance, M is the mutual inductance between the coil
and foil and 𝜔௦ = 2𝜋𝑓௦. The resonant frequency feq of the loaded tank circuit is,
𝑓eq =
ଵ
ଶగඥ௅౛౧஼౨
…………………… (3)
For half-bridge inverter, the expression of primary voltage Vpri of the transformer (see Fig.
1) is,
𝑉pri =
௏ిౄ
ଶ
= 0.9𝑛𝑅eq𝑖௅
…………………… (4)
VCH is the chopper output voltage and 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.
[0067] The rise in demand to seal container having wider cap diameter (≤200 mm) of bulk
packing of edible oil and fats, speciality chemicals and adhesives, etc. could not be meet by
the coil head of Figure 7a, it suffered from the following issues:
i) resulted under-sealing [11] at the periphery perpendicular to the conveyor axis for
140 mm cap as shown in Figure 9; and
Page 12 of 20

ii) Due to the increase in load, the controller saturates where, 𝑉େୌ(max) = 𝑉ୈେ, further
power demand would lead to decrease in coil current resulting poor quality of
sealing.

[0068] Apart from the need to seal cap with wider diameter, the mechanical rigidity of the
Aluminium foil is required, where thickness of Aluminium foil [6] is ≥30 µm requiring more
intensity of eddy current. Large-diameter foil couples more magnetic field lines beneath the
coil head. The value of M is large, it results large value of Req (2).
[0069] There are challenges to seal containers with large diameter for two reasons,
particularly when greater number of foils resides beneath the coil head. Firstly, the pattern
of distribution of transferred power on a foil would follow the field distribution created by
the coil as shown in Figure 4b; it would be non-uniform (maximum around the centre). The
power density (W/cm2) would be large at centre along the conveyer axis [2], and it would
be much less at periphery perpendicular to it. It results poor quality of sealing, as shown in
Figure 9.
[0070] Secondly, due to large value of M, the value of Req is large. However, there is a
constraint on the maximum value of Req i.e., Req(max) because, from (4), it could be written
that,
𝑅eq(max) = ௏ిౄ(୫ୟ୶)
ଵ.଼௡௜ಽ
≤
௏ీి
ଵ.଼௡௜ಽ
………………………… (3)
[0071] The value of Req(max) should not saturate the power converter, because beyond
that value the value of iL would gradually decrease where the quality of sealing would be
greatly affected. The power control circuit would not be useful beyond.

[0072] This present invention demonstrates that with design of novel coil head, extra-large
diameter containers using large foils could be sealed by induction heating approach.
Secondly, it defies the traditional rule to increase the power capacity when larger diameter
foils are used. With novel field distribution along with variable mutual coupling between the
Page 13 of 20

coil and the foils, the coil head succeeds in sealing of large containers at reduced power
drawn.
[0073] In a preferred embodiment discloses a novel coil assembly/ head comprising three
coil segments – one circular [15] and two rectangular [16] in shape as shown in Figure 10,
wherein the circular coil [15] is used to seal the major part of the lip of the container around
the conveyor axis of the conveyor [13]; while the rectangular coils [16] are placed to take
care of sealing of the lip around the periphery perpendicular to the conveyor axis [2], and
on either side of the conveyor axis [2]. These multi-axes distributed coil head [1200] helps
distribute the transferred energy on the foil in a such way that sealing take place, consuming
less energy to ensure sealing of drums and buckets (including wide mouth container) making
it energy efficient.
[0074] The field distribution of circular coil [15] for different values of inner diameter is
shown in Figure 11. The filed distribution of the circular coil [15] is uniform when the inner
diameter is increased, say, from d1 to d2. Accordingly, the value of M for the circular coil is
reduced. The value of M is kept at moderate value to avoid any saturation effect of the
power converter. The relatively flatter field distribution would improve the flatness in spatial
power distribution on foil surfaces. To avoid any saturation effect, the value of M is reduced
through multi-segmented coil design approach.
[0075] The coupling between each rectangular coil [16] and the foil is inherently small. The
design of circular coil [15] is such that it takes care of sealing of medium size containers.
The role of each rectangular coil [16] is active only when the foil [6] area is embraced by
the field of each rectangular coil [16].
Page 14 of 20

[0076] The parameters of the power controller of the novel coil head is shown in the table
below.
Component Value
Coil inductance L1: 33.8 μH
Resonant capacitor Cr: 0.47 μF
Coil current: 70 A
Resonant frequency: 40.1 kHz.
Turns ratio of TR: 14:2
Primary litz-wire conductor
area and strand size
3.53 sq. mm and 0.1mm
secondary litz-wire conductor
area and strand size
17 sq. mm and 0.1mm
Q1, Q2, Q3+D1: MMG75S060B6TC
Chopper inductance L2: 1.5 mH, 15A
Inverter topology: Zero voltage zero current
switching (ZVZCS).
Mains Current at Full Load: 6.8 A at 240 V AC
Power rating of the controller: 1.6 kW.
[0077] The present invention achieves the following purposes:
i. ensure sealing of plastic drums [7], plastic buckets [8], plastic wide mouth container
[9] using wide range foil diameter (130-190 mm);
ii. Large diameter foil [6] would not increase the power rating of the controller; and,
iii. no saturation effect when large number of foils reside beneath the coil head.
Page 15 of 20

[0078] The Test Report using the novel energy-efficient coil head for automated sealing of
containers is provided below:
Coil Parameter
Bottle/ Container sealing Parameter
Machine Parameter
[0079] The disclosed invention of cap head for sealing through induction heating is an
ideal method for providing temper-evidence packaging solutions of plastic drums [7],
bucket [8], wide-mouth container [9]. It transfers requisite energy contactless; its
start/stop time is negligible. It can be easily automated to yield high speed productivity
with zero defect in sealing. It is energy-efficient, environment friendly process. This
unique invention helps widen the application potential of induction cap sealing process.
Page 16 of 20

[0080] The present invention design of novel coil head [1200], extra-large diameter
containers using large foils [6] could be sealed by induction heating approach. Such coil
assembly/ head defies the traditional rule to increase the power capacity when larger
diameter foils are used. With novel field distribution along with variable mutual coupling
between the coil and the foils, the coil head succeeds in sealing of large containers at
reduced power drawn. The same power induction heating system could be used to seal
smaller diameter by changing with different coil head mechanically compatible.
Page 17 of 20

WE CLAIM:
1. A novel energy efficient coil-head [1200] for automated sealing of plastic drums [7]
and buckets [8,9], wherein the coil assembly comprising a set of three coil segment
each coil with predefined dimensions, each operatively connected to one another and
arranged along a planar surface wherein axis of the planar surface coincides with the
conveyor axis [2].
2. The novel energy efficient coil-head [1200] as claimed in claim 1, wherein one of the
coil segment is of circular [15] shape with predefined dimensions and remaining two
coil segments are rectangular [16] shape with predefined dimensions.
3. The novel energy efficient coil-head as claimed in claim 1, wherein the circular [15]
coil having inner diameter of 80mm and outer diameter of 255mm.
4. The novel energy efficient coil-head as claimed in claim 1, wherein the circular [15]
coil seals the lip of the container around the conveyor axis.
5. The novel energy efficient coil-head as claimed in claim 1, wherein the rectangular
[16] coils are identical and each are having Length of 245mm, Width of 105mm,
Inner width of 20mm.
6. The novel energy efficient coil-head as claimed in claim 1, wherein the rectangular
coil [16] seals the lip of the drums [7] and buckets [8,9] around the periphery
perpendicular to the conveyor axis [2] and on either side of the conveyor axis.
7. The novel energy efficient coil-head as claimed in claim 1, where in the coil is having
a resistance of 130 mΩ, inductance with ferrite core 33.8 µH, inverter frequency
40.1kHz, and resonance capacitor 0.47µf.
Page 18 of 20

8. The novel energy efficient coil-head [1200] as claimed in claim 1, wherein the foil
[6] diameter of the plastic drums [7] and buckets [8,9] range between 130mm to
190mm.
9. The novel energy efficient coil-head [1200] as claimed in claim 1, wherein a power
controller operatively connected to the coil-head configured to supply electrical
power of predefined specifications, to energize the novel coil-head for sealing.
10. The novel energy efficient coil-head [1200] as claimed in claim 1, wherein the circular
coil [15] which seals the lip of the plastic drums [7] and buckets [8,9] around the
conveyor axis [2]; and the rectangular coil [16] which seals the lip of the plastic
drums and buckets around the periphery perpendicular to the conveyor axis and on
either side of the conveyor axis, together makes the coil head a multi-axis distributed
coil head wherein the transferred energy is distributed on the foil by consuming less
energy making the coil-head energy efficient.