U.S. patent application number 13/900809 was filed with the patent office on 2013-11-28 for apparatus and process for heat treating a packaged food product.
The applicant listed for this patent is Top B.V.. Invention is credited to Henricus Johannes Schuten, Henricus Franciscus Maria van den Bosch, Aart-Jan van der Voort.
Application Number | 20130316051 13/900809 |
Document ID | / |
Family ID | 48326209 |
Filed Date | 2013-11-28 |
United States Patent
Application |
20130316051 |
Kind Code |
A1 |
van der Voort; Aart-Jan ; et
al. |
November 28, 2013 |
APPARATUS AND PROCESS FOR HEAT TREATING A PACKAGED FOOD PRODUCT
Abstract
The invention provides an apparatus (for heat treating a
packaged food product), comprising (a) a channel surrounding a
channel interior, (b) a pressurizer, (c) a transport unit, (d) a
first electrode, surrounding at least part of the channel interior
over a first electrode length, (e) an electrode configuration
comprising (i) a second electrode surrounding at least part of the
channel interior over a remote part surrounding length (for
shielding at least part of the channel), and (f) a radio frequency
wave generator configured to generate RF-waves between the first
and second electrode. With such apparatus efficiently energy may be
coupled into the packaged food product, for instance for heating a
meal and/or for pasteurizing a food product. A further advantage of
the present apparatus and such process is that it may be configured
to be used in a continuous process.
Inventors: |
van der Voort; Aart-Jan; (JA
Wageningen, NL) ; van den Bosch; Henricus Franciscus
Maria; (AC Gassel, NL) ; Schuten; Henricus
Johannes; (HP Arnhem, NL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Top B.V. |
PW Wageningen |
|
NL |
|
|
Family ID: |
48326209 |
Appl. No.: |
13/900809 |
Filed: |
May 23, 2013 |
Current U.S.
Class: |
426/234 ;
219/681; 219/700; 219/761 |
Current CPC
Class: |
A23L 5/17 20160801; H05B
6/54 20130101; A23L 3/02 20130101; Y02P 60/85 20151101; A23L 5/36
20160801; A23V 2002/00 20130101; A23L 3/005 20130101; A23L 3/045
20130101; A23L 3/01 20130101; H05B 6/60 20130101; A23L 5/15
20160801 |
Class at
Publication: |
426/234 ;
219/681; 219/700; 219/761 |
International
Class: |
A23L 3/01 20060101
A23L003/01; A23L 3/04 20060101 A23L003/04 |
Foreign Application Data
Date |
Code |
Application Number |
May 25, 2012 |
NL |
2008879 |
Claims
1. An apparatus for heat treating a packaged product in a heat
treating process, the apparatus comprising: a. a channel with a
channel length (L), a channel axis and a channel wall, wherein the
channel wall surrounds a channel interior; b. a pressurizer
configured to control the pressure of a liquid within the channel;
c. a transport unit configured to transport the packaged product in
a propagation direction through the channel; d. a first electrode,
surrounding at least part of the channel interior over a first
electrode length (L1), configured at a channel axis-to-first
electrode length (D1); e. an electrode configuration comprising (i)
a second electrode, arranged at a non-zero inter electrode distance
(L2) from the first electrode, the second electrode surrounding at
least part of the channel interior over a second electrode length
(L3) and configured at a channel axis-to-second electrode length
(D3), and (ii) an electrically conductive remote part, in
electrically conductive contact with the second electrode,
configured at a channel axis-to-remote part length (D2) wherein
D2>D3, and surrounding at least part of the channel interior
over a remote part surrounding length (L4) for shielding at least
part of the channel; f. a radio frequency (RF) wave generator
configured to generate RF-waves between the first electrode and the
second electrode, wherein the first electrode and the second
electrode are embedded in the channel wall and are in physical
contact with the interior of the channel, and wherein the channel
wall further comprises an electrically insulating material.
2. The apparatus according to claim 1, wherein the radio frequency
(RF) wave generator is configured to generate RF-waves between the
first electrode and the second electrode at a frequency selected
from the range of 10-50 MHz, wherein the packaged product comprises
a packaged food product, and wherein the second electrode is
earthed.
3. The apparatus according to claim 1, wherein the radio frequency
(RF) wave generator is configured to generate over the first
electrode and the second electrode an oscillating voltage in the
range of 100-50,000 V.
4. The apparatus according to claim 1, wherein the channel
axis-to-first electrode length (D1) is in the range of 15-100 mm,
and wherein the radio frequency (RF) wave generator is configured
to generate RF-waves between the first electrode and the second
electrode at a frequency selected from the range of 25-29 MHz.
5. The apparatus according to claim 1, wherein the channel
axis-to-first electrode length (D1) is larger than 100 mm, and
wherein the radio frequency (RF) wave generator is configured to
generate RF-waves between the first electrode and the second
electrode at a frequency selected from the range of 12-14 MHz.
6. The apparatus according to claim 1, having a ratio of the
channel axis-to-remote part length (D2) to the channel
axis-to-second first electrode length (D1) in the range of
D2/D1=1.5-7, and wherein the channel has a cylindrical shape and
wherein the electrically conductive remote part has a cylindrical
shape over the remote part surrounding length (L4), in particular
having a circle a cylindrical shape.
7. The apparatus according to claim 1, wherein the pressurizer is
configured to maintain the liquid within the channel, during use of
the apparatus, at a pressure selected from the range of 1.5-6
bar.
8. The apparatus according to claim 1, wherein the electrode
configuration comprises two sets of second electrodes and
electrically conductive remote parts, arranged at both sides of the
first electrode, wherein the two sets of second electrodes are in
physical contact with each other via the electrically conductive
remote parts.
9. A process for heat treating a packaged product comprising a
product within a package with the apparatus according to claim 1,
the process comprising transporting the packaged product through
the channel filled with the pressurized liquid and heating the
product in a treatment zone of the channel by generating RF-waves
at a frequency selected from the range of 10-50 MHz between the
first electrode and the second electrode.
10. The process according to claim 9, wherein the frequency is
selected from the range of 12-29 MHz.
11. The process according to claim 9, further comprising applying
an oscillating voltage between the first electrode and the second
electrode in the range of 100-50,000 V and maintaining the liquid
within the channel at a pressure selected from the range of 1.5-6
bar.
12. The process according to claim 9, wherein the packaged product
comprises a packaged food product, and wherein the process is a
continuous process.
13. The process according to claim 9, further comprising optimizing
the electrical energy input and output.
14. The process according to claim 9, wherein the product comprises
a food product and wherein the food product comprises a product
selected from the group consisting of a meal, a meal component, a
potato, a vegetable, meat, a dairy product, and a soup.
15. The process according to claim 9, wherein the package is
electrically insulating, wherein the liquid comprises one or more
of de-ionized water and oil, wherein the first electrode and the
second electrode are in physical contact with the pressurized
liquid, wherein the process comprises transporting the packaged
food product through the channel filled with the pressurized liquid
with a transport speed in the range of 0.1-10 cm/sec, and wherein
the second electrode is earthed.
16. An apparatus, comprising (a) a channel surrounding a channel
interior, (b) a pressurizer, (c) a transport unit, (d) a first
electrode, surrounding at least part of the channel interior over a
first electrode length, (e) an electrode configuration comprising
(i) a second electrode surrounding at least part of the channel
interior over a remote part surrounding length, and (f) a radio
frequency wave generator configured to generate RF-waves between
the first and second electrode.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of International
Application No. NL 2008879 filed May 25, 2012. The contents of this
application are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The invention relates to an apparatus for heat treating a
packaged (food) product, as well as to a process for heat treating
a packaged (food) product with such apparatus.
BACKGROUND OF THE INVENTION
[0003] Processes to heat treat food products are known in the art.
U.S. Pat. No. 4,956,532, for instance, describes a method and
apparatus for even and rapid heating, pasteurization or
sterilization of products contained in a package, such as, for
example, pharmaceutical products or food, which are conveyed
through a microwave treatment chamber on a continuous conveyor
belt. In order to heat components of the products having different
heat absorption for the purpose of reaching the pasteurization
temperature rapidly and evenly, the temperature of the components
is recorded by a temperature sensor, and on the basis of this the
computer calculates the respective AT, taking into account given
product parameters and the desired temperature to be reached. When
the product passes under the following input aperture, a given
microwave energy level is coupled into each specific component, as
a result of which an even temperature of all products in the
package is achieved very rapidly without overheating of the
product.
[0004] Further, WO2011062499 describes for instance a device for
pasteurizing a mass of foodstuff which comprises: a feed; a first
tube of an electrically and magnetically inert material suitable
for contact with foodstuff; an arrangement of electrodes added to
the first tube and connected to an RF power generator so that the
mass present in the first tube can be heated in this first tube.
Co-acting electrodes are disposed with a substantial mutual axial
interspace.
SUMMARY OF THE INVENTION
[0005] A disadvantage of prior art prior art systems may be that
they do not efficiently couple energy into the system. Further,
many prior art systems are not able to (efficiently) heat treat
packaged food products, such as for instance (packaged) meals.
Hence, it is an aspect of the invention to provide an alternative
apparatus and/or alternative process for heat treating a packaged
food product, which preferably further at least partly obviate one
or more of above-described drawbacks.
[0006] In a first aspect, the invention provides an apparatus
("apparatus") for heat treating a (packaged) product, especially a
(packaged) food product, in a ((packaged) food) heat treating
process, especially a continuous ((packaged) food) heat treating
process, the apparatus comprising:
[0007] a. a channel with a channel length, a channel axis and a
channel wall, wherein especially the channel wall surrounds a
channel interior;
[0008] b. an optional pressurizer configured to control the
pressure of a liquid within the channel (which liquid is present
during operation of the apparatus);
[0009] c. an optional transport unit configured to transport the
(packaged) product, especially the (packaged) food product, in a
propagation direction through the channel (containing the
liquid);
[0010] d. a first electrode, surrounding at least part of the
channel interior over a first electrode length, (the first
electrode) configured at a channel axis-to-first electrode length
(i.e. distance between first electrode and channel axis);
[0011] e. an electrode configuration comprising (i) a second
electrode, arranged at a non-zero inter electrode distance from the
first electrode, the second electrode surrounding at least part of
the channel interior over a second electrode length and configured
at a channel axis-to-second electrode length, and (ii) an
electrically conductive remote part ("remote part"), in
electrically conductive contact with the second electrode,
configured at a channel axis-to-remote part length (i.e. distance
between the remote part and channel axis) wherein the
axis-to-remote part length is preferably larger than the
axis-to-second electrode length, and (the electrically conductive
remote part) surrounding at least part of the channel interior over
a remote part surrounding length (for shielding at least part of
the channel);
[0012] f. a radio frequency (RF) wave generator configured to
generate RF-waves between the first electrode and the second
electrode.
[0013] In a further aspect, the invention provides a process for
heat treating a (packaged) product, especially a packaged food
product (comprising a food product within a package), especially
with the apparatus as defined herein, wherein the process comprises
transporting the (packaged food) product through a channel filled
with the pressurized liquid and heating the (food) product (i.e.
especially the food product within a package) in a treatment zone
of the channel by generating RF-waves, especially at a frequency
selected from the range of 10-50 MHz, between the first electrode
and the second electrode.
[0014] With such apparatus and such process, efficiently energy may
be coupled into the (packaged food) product. Further, with such
apparatus and such process, packaged food products may be heat
treated, for instance for heating a meal and/or for pasteurizing a
food product. A further advantage of the present apparatus and such
process is that it may be configured to be used in a continuous
process (although the present apparatus and process may also be
configured to be used in a batch process). Hence, in a further
embodiment, the invention also provides such process, wherein the
process is a continuous process. The apparatus and process are
herein especially further explained with respect to a packaged food
product as embodiment of a product, especially as embodiment of a
packaged food product.
[0015] Due to the configuration of the apparatus, a cavity is
created, wherein efficiently energy may be provided to the product,
without substantial loss of energy to the surroundings. Further,
due to the transport through the channel, all (food) products may
be subjected to the same conditions, even when there are local
variations within the channel of the RF-field.
[0016] The process that may be applied with the apparatus is herein
indicated as "heat treating process", in specific embodiments
"packaged food heat treating process", (further also shortly
indicated as "heat treating process" or simply "process"), and the
apparatus described herein is especially suitable for heat treating
a packaged food product in such packaged food heat treating
process.
[0017] The term "heat treating" may include heating the food
product, but may in another embodiment also include pasteurizing
the food product, or in yet another embodiment include sterilizing
the food product. In an embodiment, the heat treatment may include
heating the food product (surrounded by the liquid) within the
channel (especially within the treatment zone) to a temperature in
the range of 50-150.degree. C., such as 85-125.degree. C. Hence,
with the process and apparatus, the product, especially the product
in the package, can be heat treated, such as for sterilizing or
pasteurizing purposes; however, the process and apparatus may also
be applied for other purposes (see also below).
[0018] The apparatus may be configured for heat treating packaged
food products. In principle, the apparatus may also be applied for
heat treating other types of packaged products, such as a packaged
pharmaceutical product, a packaged neutraceutical product, a
packaged (medical) tool, etc. Hence, in a further aspect, the
invention provides such apparatus as described herein for heat
treating a packaged product (per se). However, the invention will
further be described with reference to (packaged) food products (as
also indicated above).
[0019] Especially, the food product may comprise a product selected
from the group consisting of a meal, a meal component, a potato, a
vegetable, meat, a dairy product, and a soup. As will be clear to a
person skilled in the art, the food product may also comprise a
combination of products, such as a food product comprising
potatoes, vegetable(s) and meat. The term food product may relate
to any product that is intended for oral human (or animal)
consumption.
[0020] Especially, the food product is packaged. As a result of the
package, the (packaged) food product can be transported with or
through the liquid, as the channel is filled with liquid (during
operation of the process) (see also below). Hence, during
processing the packaged food product may substantially be
surrounded by the (pressurized) liquid. Preferably, during
processing the packaged food product, at least in the treatment
zone (herein also indicated as "heat treatment zone"), is entirely
surrounded by the liquid. Due to the presence of the liquid, the
thermal energy generated within the channel may efficiently be
provided to the food product.
[0021] Especially, the package (of the packaged food product) is
electrically insulating. The electrical resistivity (.rho.) may for
instance be at least 5.10.sup.4 .OMEGA.m (at 20.degree. C.), such
as at least 1.10.sup.5 .OMEGA.m (at 20.degree. C.), especially at
least 1.10.sup.8 .OMEGA.m (at 20.degree. C.), even more especially
at least 1.10.sup.12 .OMEGA.m (at 20.degree. C.), such as a package
of poly ethylene (PE), like HDPE or LDPE, etc. (see also other
examples of suitable materials below, wherein those materials are
described in relation to the material of the channel wall).
[0022] The liquid used in the channel may be de-ionized water or
oil, or a combination thereof. Hence, in an embodiment, the liquid
comprises one or more of de-ionized water and oil. Also the liquid
preferably has a high electrical resistivity, such as preferably at
least 1.10.sup.1 .OMEGA.m (at 20.degree. C.), even more preferably
at least at least 1.10.sup.2 .OMEGA.m (at 20.degree. C.), yet even
more preferably at least at least 1.10.sup.3 .OMEGA.m (at
20.degree. C.), like especially at least at least 1.10.sup.4
.OMEGA.m (at 20.degree. C.), such as especially at least at least
1.10.sup.5 .OMEGA.m (at 20.degree. C.). Especially, the liquid used
in the channel may be liquid having a high dielectric constant (k),
such as at least 2, even more especially at least 5, like at least
10, such as at least 20, or even higher, like at least 20, such at
least 40 (at room temperature). How effective a dielectric is at
allowing a capacitor to store more charge may depend on the
material the dielectric is made from. Every material has a
dielectric constant k. This is the ratio of the field without the
dielectric (Eo) to the net field (E) with the dielectric
(k=Eo/E).
[0023] The packaged food product may in an embodiment comprise
"brick" like (flow) packages. The packages may for instance have a
length selected from the range of 5-100 cm, a height selected from
the range of 1-50 cm, and a width selected from the range of 1-50
cm. The volume of the packaged food product, at RT and atmospheric
pressure may for instance be in the range of 0.1-10 dm.sup.3, such
as 0.5-5 dm.sup.3.
[0024] The apparatus comprises a channel through which one or more
packaged food products may be transported. Over at least part of
the length of the channel, the packaged food products may be
treated. This is indicated as treatment zone, and is in general the
zone between the first and the second electrode(s) (see also
below); this may in an embodiment be substantially equal to the
remote surrounding length, i.e. the length over which the remote
part of the electrode configuration shields the channel.
[0025] The channel comprises a channel wall, enclosing or
surrounding a channel interior. Especially, the channel interior is
the hollow space that is enclosed by the channel wall. During use,
the channel interior is in general substantially entirely filled
with liquid Over at least part of the length, and at least the
treatment zone, during processing the channel interior will
completely be filled with the liquid (and one or more packaged food
products when during processing such one or more packaged food
products are transported through the treatment zone). The channel
interior is the volume enclosed by the channel wall. The
cross-section of the channel (especially over the treatment zone)
may for instance be square, rectangular, circular, oval,
elliptical, etc. Especially, the cross-section of the channel
(especially over the treatment zone) is selected from the group
consisting of circular, oval, and elliptical, even more especially
circular. The channel is elongated and has an axis or elongation
axis. The distance from the axis to channel wall may be in the
range of for instance 15-250 mm. Within one cross-section, this
distance may be identical over the entire cross-section (circular),
or may include different distances (like in all other cases except
circular). Hence, the terms "surrounding" and "circumferential" do
not necessarily refer to round items, but in general indicate the
perimeter.
[0026] The channel wall is electrically insulating, except for
those parts where an electrode forms optionally part of the channel
wall. Like for the package of the packaged food product, the
material of the channel wall, except for those parts where forms
optionally part of the channel wall, the electrical resistivity
(.rho.) may for instance be at least 1.10.sup.5 .OMEGA.m (at
20.degree. C.), especially at least 1.10.sup.8 .OMEGA.m (at
20.degree. C.), even more especially at least 1.10.sup.12 .OMEGA.m
(at 20.degree. C.).
[0027] Especially, the insulating material is selected from the
group consisting of PE (polyethylene), PP (polypropylene), PEN
(polyethylene naphthalate), PC (polycarbonate), polymethylacrylate
(PMA), polymethylmethacrylate (PMMA) (Plexiglas or Perspex),
cellulose acetate butyrate (CAB), silicone, polyvinylchloride
(PVC), polyethyleneterephthalate (PET), (PETG) (glycol modified
polyethyleneterephthalate), PDMS (polydimethylsiloxane), COC (cyclo
olefin copolymer), polyether ether ketone (PEEK),
poly(phenyl)sulfone (P(P)SU), polyethyleneamine (PEA),
polyethyleneimine (PEI), polyimide (PI), poly(phenylene oxide)
(PPO) and polybenzimidazole (PBI). As will be clear to a person
skilled in the art, also a combination of (such) materials may be
applied.
[0028] The apparatus may further comprise a pressurizer. Such
pressurizer may include a pump, to bring the liquid (within the
channel, and at least over the treatment zone) at the desired
pressure. Alternatively or additionally, the pressurizer may
comprise one or more pressure towers (sometimes also indicated as
"tower-type sterilizer" or "water column" or "water column type
sterilizer"), i.e. columns with liquid that can be used to build up
pressure. Upstream and downstream of the heat treatment zone,
pressure locks may be arranged to keep the pressure in the
treatment zone at the desired value. Especially, the pressurizer is
configured to maintain the liquid within the channel (over at least
a part of the channel defined by the remote part surrounding
length) at a pressure of over 1 bar, especially at a pressure
selected from the range of 1.5-6 bars, especially 2-5 bar (during
operation of the process). Hence, in an embodiment, the pressurizer
is configured to maintain the liquid within the treatment zone at a
pressure selected from the range of 1.5-6 bar, especially 2-5 bar.
Therefore, the process of the invention may further comprise
maintaining the liquid within the channel at a pressure of over 1
bar, especially at a pressure selected from the range of 1.5-6 bar,
especially 2-5 bar.
[0029] The apparatus may further comprise a transport unit,
configured to transport the packaged food product in a propagation
direction through the channel. The transport unit can be any unit
that is suitable to transport the packaged food product(s) through
the channel. As will be clear to the person skilled in the art, in
certain embodiments the transport unit may thus (also) be
configured to transport the (packaged) (non-food) product in a
propagation direction through the channel
[0030] The liquid within the channel may be stationary, but the
liquid may also flow through the channel. Hence, a unit that is
configured to generate the liquid flow may also have the function
of transport unit. Hence, a pump or other means that is configured
to transport the liquid through the channel might be used as
pressurizer and/or transport unit. However, the apparatus may be
configured and/or the process may be designed to have substantially
no flow of the liquid. Hence, in an additional or alternative
option, the apparatus may have a (separate) transport unit
configured to push the packaged food products through the channel
or to pull a train of packaged food products through the channel.
For instance, the packages can continuously be transported through
the channel by pushing the upstream product and keeping the
downstream products in a head-to-tail position. The transport unit
may comprise a chain or rotators for transporting the packaged food
products through the channel. Alternatively or additionally, the
transport unit may be configured to push the packaged food product
through the channel. For instance, the packaged food product may be
transported in trays, which are pushed through the channel.
[0031] The process of the invention may further comprise
transporting the packaged food product through the channel filled
with the pressurized liquid with a transport speed in the range of
0.1-10 cm/sec, such as 0.5-5 cm/sec. Hence, the transport unit may
be configured to transport the packaged food product through the
channel (filled with the pressurized liquid) with a transport speed
in the range of 0.1-10 cm/sec, such as 0.5-5 cm/sec.
[0032] A further element of the apparatus is the combination of
first electrode and electrode configuration containing the second
electrode. The electrodes are used to create the RF field, and the
electrode configuration is especially be configured to
substantially confine the RF field within a cavity. In this way,
the energy may efficiently be applied to heat treat the products,
especially the (packaged) food products, within the treatment
zone.
[0033] The apparatus comprises above-mentioned first electrode,
surrounding at least part of the channel interior over a first
electrode length, configured at a channel axis-to-first electrode
length. When seen in a cross-sectional view, this especially
implies that the first electrode at least partially surrounds the
channel interior. Preferably, the first electrode entirely
surrounds the channel interior, i.e. a first electrode having a
square, rectangular, circular, oval, elliptical, etc. shape (when
seen in a cross-sectional view) (see also above in relation to the
geometry of the channel). Further, such first electrode has a
length (i.e. the length in a direction parallel to the channel
axis), the first electrode length, which may be in the range of 1
mm to 50 cm. Especially, the first electrode is embedded in the
channel wall. Hence, the distance (radius in case of a channel
having a circular cross-section) of the first electrode to the
channel axis, i.e. the channel axis-to-first electrode length may
(substantially) be the same as the distance of the channel axis to
the channel wall (at positions within the channel (within the
treatment zone), where there is no electrode (but insulating
material, see also above)).
[0034] At non-zero distance from the first electrode, one or two
(or optionally more), second electrodes may be arranged. The second
electrode is especially part of an electrode configuration, see
below.
[0035] Hence, the apparatus may comprise also above-mentioned
second electrode, surrounding at least part of the channel interior
over a second electrode length, configured at a channel
axis-to-second electrode length. When seen in a cross-sectional
view, this implies that the second electrode at least partially
surrounds the channel interior. Preferably, the second electrode
entirely surrounds the channel interior, i.e. an second electrode
having a square, rectangular, circular, oval, elliptical, etc.
shape (when seen in a cross-sectional view) (see also above in
relation to the geometry of the channel). Further, such second
electrode has a length (i.e. the length in a direction parallel to
the channel axis), the second electrode length, which may be in the
range of 1 mm to 50 cm. Especially, the second electrode is
embedded in the channel wall. Hence, the distance (radius in case
of a channel having a circular cross-section) of the second
electrode to the channel axis, i.e. the channel axis-to-second
electrode length may (substantially) be the same as the distance of
the channel axis to the channel wall (at positions within the
channel (within the treatment zone), where there is no electrode
(but insulating material, see also above)).
[0036] The remote part may also be indicated as part for shielding
the electrical field or mantle. The remote part may coaxially
surround at least part of the channel (see also below). Hence, in
an embodiment, the remote part is configured to coaxially surround
at least part of the channel. Especially, the first electrode is
configured at that part of the channel wall that is also coaxially
surrounded by the remote part.
[0037] Therefore, in an embodiment the first electrode and the
second electrode are embedded the channel wall and are in physical
contact with the interior of the channel, and the channel wall
further comprises an electrically insulating material. Hence, when
liquid flows through the channel, the liquid will be in contact
with the first and second electrode(s); hence, when the channel is
empty, and filled with for instance, air, the first and the second
electrode are in physical contact with the air. For this reason,
the liquid is substantially not electrical conductive (see also
above). Hence, during processing the first electrode and the second
electrode may be in physical contact with the pressurized liquid.
Thus, in an embodiment the electrodes are not disposed electrically
insulated relative to the inner surface of the channel wall (coming
into direct contact with the liquid).
[0038] In general, the apparatus will comprise a set of the first
electrode and the second electrode, or a set of the first electrode
and at both sides of the first electrode two second electrodes
(being arranged)(see also below). As will be clear to a person
skilled in the art, the apparatus may also comprise a plurality of
such sets of first electrode and second electrode(s). Hence, the
first and the second electrode(s) are arranged at a substantial
mutual axial interspace (between the first and the second
electrode(s, respectively).
[0039] Below, first the electrode configuration is elucidated in
more detail. As indicated above, the apparatus comprises an
electrode configuration comprising (i) the second electrode (see
also above), and (ii) an electrically conductive remote part, in
electrically conductive contact with the second electrode,
configured at a channel axis-to-remote part length wherein
axis-to-remote part length is larger than the axis-to-second
electrode length, and surrounding at least part of the channel
interior over a remote part surrounding length (for shielding at
least part of the channel).
[0040] Hence, the electrode configuration may comprise a kind of a
coaxial arranged electrode or electrode configuration, with the
electrode itself at a short distance from the channel axis and a
remote part, a kind of mantle, arranged at a larger distance from
the channel axis than the (first and the) second electrode, and
configured to at least partially enclose, (especially) at a
non-zero distance from the channel wall, the channel. In this way,
at least part of the channel, especially at least a substantial
part of the heat treatment zone, is shielded by the remote part. In
this way, the RF-field may be substantially contained in a cavity.
This cavity may be formed by the electrode configuration.
[0041] For instance, in a specific embodiment the channel may have
a cylindrical shape and the electrically conductive remote part has
a cylindrical shape over the remote part surrounding length. Hence,
in an embodiment both the channel and the remote part have a
cylindrical cross section.
[0042] In a specific embodiment, the electrode configuration
comprises two sets of second electrodes and electrically conductive
remote parts, arranged at both sides of the first electrode,
wherein the two sets of second electrodes are in physical contact
with each other via the electrically conductive remote parts. In
this way, a kind of remote channel or mantle may be arranged
shielding the heat treatment zone. Thus, in an embodiment, a
coaxial arrangement of the channel (with electrodes) and the remote
part(s), which is in electrical connection with the second
electrode(s), coaxially enclosing the channel may be provided. Note
that the two sets of electrically conductive remote parts may (in
fact) be a single unit (with an opening in the remote part for
introduction of the currency conductor (such as an electrical wire)
for the first electrode.
[0043] Especially preferred is that the second electrode is
earthed. Further, optionally the channel with first electrode and
electrode configuration may electronically be shielded in a Faraday
cage.
[0044] Further, the apparatus may comprise a radio frequency (RF)
wave generator configured to generate RF-waves between the first
electrode and the second electrode. Of course, when there are more
sets of first electrode and second electrode(s), the RF wave
generator may be arranged to generate RF-waves between the first
electrode and the second electrode(s) of each set. However, in case
there are more sets of first electrode and second electrode(s),
optionally each set may be driven by a separate radio frequency
wave generator.
[0045] Optionally, the electrodes are coupled to the associated RF
generator via an adjustable impedance matching circuit. Such
impedance matching circuit may be applied to further comprise in
the process (the ability) of optimizing the electrical energy input
and output. The one or more of the frequency, the voltage and the
impedance may be adjusted with the impedance matching circuit to
optimize energy input in the cavity, more especially the thermal
treatment zone, even more especially the packaged food products,
and to minimize energy loss out of the thermal treatment zone. In
an embodiment, the impedance matching circuit may comprise a
variable capacitor connected in series and a variable second
capacitor connected in parallel to electrodes.
[0046] In a specific embodiment, the radio frequency (RF) wave
generator (optionally in combination with the impedance matching
circuit) is configured to generate RF-waves between the first
electrode and the second electrode at a frequency selected from the
range of 10-50 MHz, especially 12-29 MHz. Further, the radio
frequency (RF) wave generator may be configured to generate over
the first electrode and the second electrode an oscillating voltage
in the range of 100-50,000 V (i.e. 0.1-50 kV). Therefore, in the
process of the invention the frequency (of the RF field) may be
selected from the range of 12-29 MHz, especially 13.56 MHz or 27.12
MHz. The process may further comprise applying an oscillating
voltage between the first electrode and the second electrode in the
range of 100-50,000 V.
[0047] With respect to dimensions, in an embodiment the channel
axis-to-first electrode length may be in the range of 10-500 mm,
especially 15-250 mm, like 20-150 mm. The same may apply to the
axis-to-second electrode length. Especially, when the channel
axis-to-first electrode length (and axis-to-second electrode
length) is in the range of 10-100 mm, such as 15-100 mm, the radio
frequency (RF) wave generator may be configured to generate
RF-waves between the first electrode and the second electrode at a
frequency selected from the range of 25-29 MHz, especially 27.12
MHz. Especially, when the channel axis-to-first electrode length
(and axis-to-second electrode length) is larger than 100 mm, the
radio frequency (RF) wave generator is may be configured to
generate RF-waves between the first electrode and the second
electrode at a frequency selected from the range of 12-14 MHz.
[0048] Further, preferably the apparatus has a ratio of the channel
axis-to-remote part length to the channel axis-to-second first
electrode length (and axis-to-second electrode length) in the range
of 1.5-7, especially 2-4. This may especially provide a good
shielding.
[0049] The first electrode length and the second electrode length
(i.e. the length along or parallel to the channel axis) may
independently be selected from the range of 0.1 mm-50 cm, such as 1
mm-20 cm. The inter-electrode distance between the first electrode
and the second electrode may be selected from the range of 1.5
mm-50 m, but may in general be selected from the range of 20 cm-20
m, such as 20 cm-10 m. The remote part surrounding length may
substantially be equal to the inter-electrode distance, i.e.
[0050] In an embodiment, the apparatus has a ratio of the second
electrode length to the first electrode length in the range of
0.1-50, such as 1-50, like 1-10, such as 1-2, like 1.5. Further, in
an embodiment, the apparatus has a ratio of the first electrode
length to the channel axis-to-second electrode length in the range
of 0.1-4, especially 1-3.
[0051] Hence, the invention provides an apparatus (for heat
treating a packaged food product), comprising (a) a channel
surrounding a channel interior, (b) a pressurizer, (c) a transport
unit, (d) a first electrode, surrounding at least part of the
channel interior over a first electrode length, (e) an electrode
configuration comprising (i) a second electrode surrounding at
least part of the channel interior over a remote part surrounding
length (for shielding at least part of the channel), and (f) a
radio frequency wave generator configured to generate RF-waves
between the first and second electrode. With such apparatus
efficiently energy may be coupled into the packaged food product,
for instance for heating a meal and/or for pasteurizing a food
product. A further advantage of the present apparatus and such
process is that it may be configured to be used in a continuous
process.
[0052] The terms "upstream" and "downstream" relate to an
arrangement of items or features relative to the propagation of the
liquid in the channel, wherein relative to a first position within
the channel, a second position in the channel closer to the an
inlet of the packaged food product is "upstream", and a third
position within the beam of light further away from an inlet of the
packaged food product (but closer to an outlet for the heat treated
packaged food product) is "downstream".
[0053] The term "substantially" herein, such as in "substantially
consists", will be understood by the person skilled in the art. The
term "substantially" may also include embodiments with "entirely",
"completely", "all", etc. Hence, in embodiments the adjective
substantially may also be removed. Where applicable, the term
"substantially" may also relate to 90% or higher, such as 95% or
higher, especially 99% or higher, even more especially 99.5% or
higher, including 100%. The term "comprise" includes also
embodiments wherein the term "comprises" means "consists of".
[0054] Furthermore, the terms first, second, third and the like in
the description and in the claims, are used for distinguishing
between similar elements and not necessarily for describing a
sequential or chronological order. It is to be understood that the
terms so used are interchangeable under appropriate circumstances
and that the embodiments of the invention described herein are
capable of operation in other sequences than described or
illustrated herein.
[0055] The apparatus herein are amongst others described during
operation. As will be clear to the person skilled in the art, the
invention is not limited to methods of operation or devices in
operation.
[0056] It should be noted that the above-mentioned embodiments
illustrate rather than limit the invention, and that those skilled
in the art will be able to design many alternative embodiments
without departing from the scope of the appended claims. In the
claims, any reference signs placed between parentheses shall not be
construed as limiting the claim. Use of the verb "to comprise" and
its conjugations does not exclude the presence of elements or steps
other than those stated in a claim. The article "a" or "an"
preceding an element does not exclude the presence of a plurality
of such elements. The invention may be implemented by means of
hardware comprising several distinct elements, and by means of a
suitably programmed computer. In the device or apparatus claims
enumerating several means, several of these means may be embodied
by one and the same item of hardware. The mere fact that certain
measures are recited in mutually different dependent claims does
not indicate that a combination of these measures cannot be used to
advantage.
[0057] The invention further applies to an apparatus comprising one
or more of the characterising features described in the description
and/or shown in the attached drawings. The invention further
pertains to a method or process comprising one or more of the
characterizing features described in the description and/or shown
in the attached drawings.
[0058] The various aspects discussed in this patent can be combined
in order to provide additional advantages. Furthermore, some of the
features can form the basis for one or more divisional
applications.
BRIEF DESCRIPTION OF THE DRAWINGS
[0059] Embodiments of the invention will now be described, by way
of example only, with reference to the accompanying schematic
drawings in which corresponding reference symbols indicate
corresponding parts, and in which:
[0060] FIG. 1a schematically depicts an embodiment of the
apparatus; FIGS. 1b-1c schematically depict other embodiments of
the apparatus, including for the sake of understanding of the
process some packaged food products within the channel;
[0061] FIGS. 2a-2c schematically depict some further aspects of the
invention; and
[0062] FIGS. 3a-3c schematically also depict some further aspects
of the invention.
[0063] The drawings are not necessarily on scale.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0064] FIG. 1a schematically depicts an embodiment of the
apparatus, indicated with reference 1 for heat treating a packaged
food product (not depicted, however see amongst others FIGS. 1b-1c)
in e.g. a continuous packaged food heat treating process. The
apparatus 1 comprises a channel 100 with a channel length L, a
channel axis 110 and a channel wall 103 (of insulating material,
except where the electrodes are; see also below). The channel wall
103 surrounds a channel interior 105. Here, the channel interior is
empty, but during processing, the channel interior 105 will be in
general be filled with (pressurized) liquid (such as de-ionized a
water). The apparatus also comprises a pressurizer (schematically
depicted) configured to control the pressure of the liquid (not
depicted, however see amongst others FIGS. 1b-1c) within the
channel 100. Further, the apparatus comprises a transport unit 300
configured to transport the packaged food product in a propagation
direction 102 through the channel 100 (or through the channel
interior 105).
[0065] The apparatus 1 further comprises a first electrode 410,
surrounding at least part of the channel interior 105 over a first
electrode length L1, configured at a channel axis-to-first
electrode length D1, which is in this embodiment in fact also the
distance between the channel axis 110 and the channel wall (i.e.
its surface, indicated as channel wall surface 104).
[0066] Further, the apparatus 1 comprises an electrode
configuration 415 comprising (i) a second electrode 420, arranged
at a non-zero inter electrode distance L2 from the first electrode
410. The second electrode 420 also surrounds at least part of the
channel interior 105, here over a second electrode length L3. The
second electrode is configured at a channel axis-to-second
electrode length D3 (which has in general the same value(s) as for
the first electrode 410 (i.e. D1)), and which is in this embodiment
in fact also the distance between the channel axis 110 and the
channel wall (i.e. its surface, indicated as channel wall surface
104). The electrical connection between the RF generator 400 and
the first electrode, indicate with reference 412, can (also) be
considered a non-parallel part.
[0067] The electrode configuration 415 further comprises (ii) an
electrically conductive remote part 421 (remote part), in
electrically conductive contact with the second electrode 420. The
remote part allows the electrode configuration to be used as
shielding electrode or outer electrode. For instance, the second
420 electrode and remote part 421 may be of stainless steel. The
remote part is configured at a channel axis-to-remote part length
D2 wherein D2>D3. Further, the remote part 421 may at least
partially surround the channel 100 over a remote part surrounding
length L4 for shielding at least part of the channel 100. In
general, this length L4 may be substantially be the same as L2.
Further, this length L4 can also be considered as describing the
heat treatment zone 10, although this zone 10 may extend at least
partly beyond the shielded part defined by L4.
[0068] Note that the electrode configuration in FIG. 1a-1c
comprises the second electrode 420, a non-parallel part 422, and a
parallel part 421. The parallel part, i.e. the part arranged
substantially to the channel axis/channel wall. Especially the
latter part may in fact define the length L4, as this element is
substantial in shielding the RF field. Further, note that the
electrode configuration, especially the non-parallel part 422 and a
parallel part 421, coaxially surrounds the channel, and thereby
form a kind of cavity, indicated with reference 425.
[0069] In FIG. 1a, the electrode configuration 415 comprises two
sets of second electrodes (420a,420b; see also FIG. 1b) and
electrically conductive remote parts 421a,421b, arranged at both
sides of the first electrode 410, wherein the two sets of second
electrodes 420a,420b are in physical contact with each other via
the electrically conductive remote parts 421a,421b. Likewise, the
respective non-parallel parts are indicated with reference 422a and
422b. The entire electrode configuration 415 and/or the first
electrode may for instance be of stainless steel.
[0070] The apparatus further comprises a radio frequency (RF) wave
generator 400 configured to generate RF-waves between the first
electrode 410 and the second electrode 420. Optionally, the RF wave
generator 400 may further include a adjustable impedance matching
circuit 480, to modulate the RF field between the first and second
electrode(s).
[0071] As schematically depicted in FIG. 1a (and also 1b-1c (and
2a)), the first electrode 410 and the second electrode 420 are (in
these embodiments) embedded in the channel wall 103 and are in
physical contact with the interior 105 of the channel 100. The
channel wall 103 further comprises an electrically insulating
material (except for the electrodes 410,420). Further, the second
electrode 420 may be earthed.
[0072] The apparatus also comprises a pressurizer 200 configured to
control the pressure of a liquid 5 within the channel 100. This is
very schematically indicated. In an embodiment, this may be a pump,
in yet another embodiment, it comprises one or more (connected)
columns, configured to build up pressure with the liquid.
[0073] Also very schematically indicated is a transport unit 300,
which is configured to transport the packaged food product 60 in a
propagation direction 102 through the channel 100. Part of the
transport unit may be configured within the channel 100 (not
indicated), such as for instance a chain, a transportable platform,
a transportable tray, a transportable rack, rotatable wheels, a
conveyor belt, etc. etc. (see also FIGS. 3a and 3b).
[0074] Reference 500 may refer to a control unit, configured to
control the process and/or one or more elements of the apparatus 1,
such as e.g. the pressurizer.
[0075] For the sake of understanding, FIG. 1b and onward to not
always depict all elements of the apparatus, such as the (optional)
pressurizer 200 or the (optional) transport unit 300, etc.
[0076] FIGS. 1b and 1c schematically depict alternative
embodiments, with FIG. 1b schematically depicting substantially the
same embodiment as depicted in FIG. 1a, and with FIG. 1c
schematically depicting an (asymmetrical) embodiment wherein the
electrode configuration comprises a single second electrode 420 and
remote part 420, arranged at one side of the first electrode 410.
Note that especially in the latter case, shielding with a Faraday
cage, indicated with reference 470 may be desired.
[0077] In FIG. 1c, in fact the first electrode 410 can be
considered to be of another electrode configuration, comprising the
first electrode 410 and an electrical conductive remote part 411,
in electrical conductive contact with the first electrode 410,
configured at a distance db from the (first) electrically
conductive remote part 421, and preferably arranged parallel with
the (first) electrically conductive remote part 421. The electrical
conductive remote part 411 is in electrical connection with the
first electrode via the non-parallel part 412 of the first
electrode. This non-parallel part 412 of the first electrode is in
electrical contact with the radio frequency generator, and is
earthed (grounded). At the opposite end of the electrical
conductive remote part 411, it is in electrical contact with the
non-parallel part 422 of the second electrode. The RF-generator 400
may be configured to have a current in the order of 10 A-1000 A
through the (first) electrically conductive remote part 421 (and
(second) electrically conductive remote part 411). The distance of
the channel wall to the (first) electrically conductive remote part
421 is indicated with reference da; the distance of the (second)
electrically conductive remote part 411 to the (first) electrically
conductive remote part 421 is indicated with reference db.
Especially db>da, even more especially db/da.gtoreq.3. Hence,
this embodiment comprises two coaxially arranged surrounding
electrically conductive parts.
[0078] FIG. 2a schematically depicts a cross-sectional view of an
embodiment of part of the apparatus 1. Here, a channel 100 with a
round or circular cross-section is depicted. However, channels 100
with other cross sections may also be possible. The cross-sectional
shape of the channel 100 may even vary along the channel axis 110.
First electrode 410 here completely surrounds the channel interior
105.
[0079] FIG. 2b very schematically depicts an embodiment of the
apparatus, wherein downstream of the heat treatment unit 400, an
optional cooling unit 70 is arranged. The cooling unit provides a
cooling zone, wherein the heat treated packaged food product may
optionally be cooled. The cooling unit 70 may include a heat
exchanger. Part of the energy extracted from the system may be
reintroduced into the heat treatment zone, if desired.
[0080] FIG. 2c very schematically depicts another system wherein
the liquid can flow in a return system and wherein unit 80 may be
used to (further) cool the liquid. For instance, this may be done
with a heat exchanger. Part of the energy extracted from the system
may be reintroduced into the heat treatment zone, if desired.
[0081] As can be derived from the above drawings, when the liquid
flows through the channel, the liquid will be in contact with the
first and second electrode(s).
[0082] FIG. 3a very schematically depicts an embodiment of the
apparatus 1, wherein the transport unit 300 comprises a transporter
310, which may for instance be a (rotating) chain, a conveyor belt,
etc. Reference 310 indicates the transport direction. Further, this
schematic drawing depicts the use of pressure locks 210, one
upstream and one downstream of the treatment zone 10. For the sake
of understanding, other items of the apparatus are not
displayed.
[0083] FIG. 3b schematically depicts an embodiment wherein part of
the channel 100 is curved, and has a column that may be used to
build up pressure by the liquid column. Hence, this simple shape
may already be used as pressurizer 200. However, other pressurizes
may also be applied. Pressure locks, not depicted, may maintain the
desired pressure over (at least) the heat treatment zone.
[0084] FIG. 3c schematically depicts an embodiment of the packaged
food product 60, comprising a food product 61 contained by packaged
62. The package is fluid impermeable, i.e. the food product 61 is
hermetically sealed from the liquid when being processed in the
apparatus.
* * * * *