Note: Descriptions are shown in the official language in which they were submitted.
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COOKING APPARATUS WITH WATER CIRCULATION SYSTEM
The present invention relates to the field of cooking equipment and in
particular
to a cooking apparatus.
To cook rice with low Glycemic index, the electric rice cookers of the prior
art are
equipped with a water tank, and water is pumped from the water tank into the
io internal pot of the rice cooker. The base of the internal pot is
equipped with a
water discharge hole. During rice washing, water is sprayed downwards and
towards the interior of the internal pot to wash the rice contained within the
pot.
The water then flows out from the water discharge hole at the base of the
internal
pot into the water drain at the bottom of the pot. A portion of the starch and
sugar
content of the rice is washed out together with the water. After rice washing
and
soaking are completed, the water discharge hole at the base of the internal
pot
will be closed. Thereafter, a specific amount of water will be added into the
internal pot to cook the rice.
The electric rice cookers of the prior art must be equipped with a water tank,
water
discharge hole, water drain and other structures, which makes them rather
complex and difficult to seal and wash.
The main object of the present invention is to provide a cooking apparatus
that is
.. structurally simple and yet able to produce cooked rice with low sugar
content.
To achieve the above object, the present invention provides a cooking
apparatus,
which comprises an internal pot, a heating means, a steamer that is housed
within
the internal pot, as well as a water circulation system, which is connected
with
the internal pot and steamer to channel water from the internal pot to the
steamer.
The heating means is used to heat up the internal pot.
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Further, the water circulation system comprises a flow directing conduit, and
one
end of the flow directing conduit is disposed within the internal pot, while
the other
end extends into the steamer. The external wall of the steamer is engaged with
the internal pot in a sealed engagement.
Further, the flow directing conduit comprises: a steamer suction tube, which
is
connected with the steamer; a water discharge tube, which is connected to both
the steamer suction tube and the steamer.
io Further, the steamer suction tube and the steamer is integrated in one
unit.
Further, the cooking apparatus also comprises: an external housing, wherein
both the internal pot and heating means are disposed within the external
housing;
a top cover, which is disposed on the external housing, and the water
discharge
tube is disposed on the top cover.
Further, the water circulation system comprises a suction pump that is
provided
on the flow directing conduit, and the suction pump is used to draw water from
the internal pot into the steamer.
Further, the internal diameter of the steamer suction tube is at least 0.5mm
and
at most 20mm.
Further, the internal diameter of the steamer suction tube is at least 1.5mm
and
at most 12mm.
Further, the water drainage hole is disposed on the bottom and/or side wall of
the
steamer.
Further, the bottom wall of the steamer protrudes upwards such that it is
higher
at the center and lower at the edges.
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Further, the end of the flow directing conduit that extends into the steamer
is
equipped with a nozzle.
Further, the end of the flow directing conduit that extends into the steamer
is
equipped with a nozzle.
Further, there is a height difference of H1 between the lowest points on the
bottom walls of the internal pot and steamer, and H1 is at least 0.1H and at
most
0.8H, where H is the height of the internal pot.
lo
Further, there is a height difference of H2 between the lowest point of the
bottom
wall of the steamer and the mouth of the internal pot, and H2 is at least 0.1H
and
at most 0.8H, where H is the height of the internal pot.
The cooking apparatus according to the present invention comprises an internal
pot, a heating means, a steamer that is housed within the internal pot, as
well as
a water circulation system, which is connected with the internal pot and
steamer.
The heating means is used to heat up the internal pot. Hence, the cooking
apparatus according to the present invention does not require a water
discharge
hole, water drain or other related structures, can have a simple structure. By
separating rice cooking and steaming processes using the steamer, the starch
and sugar contents of the rice are reduced when they are washed from the rice
and enter into the rice water in the internal pot. This lowers the sugar
content of
the cooked rice and produces low glycemic index rice. Further, water is
recycled
and reused by producing steam to be used for steaming the rice from the water
that was used to wash the rice.
The drawings constitute a portion of the Description for further understanding
of
the present invention. These drawings illustrate the embodiments of the
present
invention and explain the principle of the present invention together with the
Description. They are not intended to limit the scope of the utility model. In
the
drawings:
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FIG. 1 is a schematic structural view of a cooking apparatus according to the
first
embodiment of the present invention;
FIG. 2 illustrates the relative positions of the steamer and the internal pot
from
FIG. 1, before the internal pot is filled with water;
FIG. 3 illustrates the relative positions of the internal pot, steamer, flow
directing
conduit and suction pump from FIG. 1, before rice comes into contact with
water;
io FIG. 4 illustrates the relative positions of the internal pot, steamer,
flow directing
conduit and suction pump from FIG. 1 during the rice washing step;
FIG. 5 is a schematic structural view of a cooking apparatus according to the
second embodiment of the present invention;
FIG. 6 illustrates the relative positions of the internal pot, steamer and
flow
directing conduit in FIG. 5 before the rice washing step and before rice has
come
into contact with water;
FIG. 7 illustrates the relative positions of the internal pot, steamer and
flow
directing conduit in FIG. 5 during the rice washing step;
FIG. 8 is a flowchart depicting the process of cooking rice using the cooking
apparatus in FIG. 1; and
FIG. 9 is a flowchart depicting the process of cooking rice using the cooking
apparatus in FIG. 5.
Wherein the above-mentioned figures comprise following reference numbers:
10. Internal pot; 20. Steamer; 21. Water drainage hole; 22. Bearing cavity;
23.
Protruding part; 30. Flow directing conduit; 31. Steamer suction tube; 32.
Water
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discharge tube; 33. Nozzle; 40. Suction pump; 50. External housing; 60. Top
cover; 70. First sealing ring; 80. Heating means.
It should be noted that the particular features of any specific embodiment may
be
5 combined in any suitable manner with one or more other specific
embodiments.
Representative embodiments of the present invention are explained hereinafter
with reference to the accompanying drawings.
It is to be understood that the following detailed description are exemplary
and
explanatory, and are intended to provide further explanation of the invention.
Unless otherwise defined, all terms (including technical and scientific terms)
used
herein have the same meaning as commonly understood by one of ordinary skill
in the art to which this invention belongs.
In the present invention, terms indicating orientation or direction, such as
"up,
down, top or bottom" are not intended to be absolute terms unless the context
requires or indicates otherwise. These terms will normally refer to
orientations
shown in the drawings. Similarly, to facilitate understanding and description,
"internal" and "external" refer to a positioning with respect to the boundary
of the
part itself. The above terms are not intended to restrict the scope of this
invention.
The cooking apparatus of the present invention is structurally simple and able
to
fulfil the object of lowering the Glycemic index value of the cooked rice.
As shown in FIG. 1 to 4, the cooking apparatus of the first preferred
embodiment
of the present invention comprises internal pot 10, heating means 80, a water
circulation system connected to internal pot 10 and steamer 20, and a steamer
20 housed within internal pot 10. Heating means 80 heats up internal pot 10.
In this way, compared to cooking apparatuses of the prior art that requires a
water
tank, water outlet, drainage pipe, the cooking apparatus according to the
present
invention is equipped with a water circulation system to circulate water
between
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internal pot 10 and steamer 20, which prevents wastage of water resources. As
the cooking apparatus according to the present invention is not equipped with
a
water tank or drainage pipe, the apparatus is structurally simpler and of
smaller
size, and is hence easier to use and clean. Furthermore, the cooking apparatus
according to the present invention does not have the problems associated with
cooking apparatuses of the prior art, such as ensuring proper sealing of the
water
outlet, difficulty in washing the internal pot, difficulty in placing the
internal pot
during usage, etc.
io As shown in FIG. 1 to 4, in the first preferred embodiment of the
present invention,
the bottom wall of steamer 20 has a protruding part 23 that protrudes towards
the
inside of steamer 20. Specifically, the center part of the bottom wall of
steamer
20 protrudes upwards such that the center of the bottom wall of steamer 20 is
higher at its center and lower at the edges. Thus, during rice steaming, the
water
rising in internal pot 10 can be prevented from coming into contact with the
rice,
and rice is cooked through steaming to produce rice of better taste.
Optionally, steamer 20 can be cylindrical, pyramidal, hexahedral or other
shapes.
As shown in FIG. 2, to ensure that the bubbling rice milk in internal pot 10
does
not come into contact with the rice during the rice steaming process, the
lowest
point of the bottom wall of internal pot 10 is at a distance H1 from the
lowest point
of the bottom wall of steamer 20, and H1 is at least 0.1H and at most 0.8H,
where
H is the height of the internal pot 10, i.e. the distance between the bottom
wall
and mouth of internal pot 10.
As shown in FIG. 2, the distance between the lowest point of the bottom wall
of
steamer 20 and the mouth of internal pot 10 is H2, and H2 is at least 0.1H and
at
most 0.8H, where H is the height of internal pot 10.
As shown in FIG. 1 and 2, steamer 20 has a water drainage hole 21 and bearing
cavity 22. After rice washing, water flows into internal pot 10 via water
drainage
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hole 21.
Specifically, water drainage hole 21 is a plurality of holes. Said plurality
of water
drainage holes 21 are located at the bottom wall of steamer 20.
Preferably, the plurality of water drainage holes 21 are all located on
protruding
part 23. Of course, in alternative embodiments not shown in the figures, the
plurality of water drainage holes 21 can also be located on the side wall of
steamer 20.
Optionally, to ensure that the rice in steamer 20 will not escape through the
water
drainage holes 21, the cross-section of each water drainage hole 21 can be
circular, elliptical, rectangular or polygonal.
When water drainage hole 21 takes the shape of an irregular polygon, the
largest
dimension of water drainage hole 21 is at least 0.5mm and at most 30mm.
Optionally, the largest dimension of the irregular polygonal water drainage
hole
21 is at least 0.8mm and at most 20mm.
As shown in FIG. 1 to 4, the water circulation system comprises flow directing
conduit 30 and suction pump 40 disposed on the flow directing conduit 30. In
this
embodiment of the cooking apparatus, suction pump 40 is used to push water
from internal pot 10 smoothly into steamer 20 (i.e. bearing cavity 22) to wash
the
rice contained within steamer 20 and to let the rice to absorb water.
As shown in FIG. 2 to 4, the external wall of steamer 20 is connected to the
mouth
of internal pot 10 in a sealed connection. Of course, in this specific
embodiment,
steamer 20 and internal pot 10 need not be connected through a sealed
structure.
In this set-up, one end of flow directing conduit 30 is located within
internal pot
10 but outside steamer 20, and the other end of flow directing conduit 30
extends
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into steamer 20.
Specifically, as shown in FIG. 2 and 4, flow directing conduit 30 comprises a
steamer suction tube 31 and water discharge tube 32 that is connected to
steamer suction tube 31.
To facilitate assembly, flow directing conduit 30 and steamer suction tube 31
can
be integrated with steamer 20.
io As shown in FIG. 3 and 4, the end of water discharge tube 32 that points
towards
steamer 20 is fitted with nozzle 33, so as to spray water evenly on the rice
contained within steamer 20. This ensures that all rice grains can absorb an
adequate amount of water.
As shown in FIG. 1, the cooking apparatus further comprises external housing
50
and top cover 60, and internal pot 10 is disposed within external housing 50;
top
cover 60 is fitted on top of external housing 50. Water discharge tube 32 and
suction pump 40 are fitted on top cover 60.
The cooking apparatus described above is an electric rice cooker, but can also
be a microwave, electric slow cooker or electric pressure cooker.
Optionally, heating means 80 is a heating device selected from the group
comprising a heating plate, heating tube, IH electromagnetic heating device
and
heating film.
It should be noted that before using the cooking apparatus according to the
present invention, rice must be added to bearing cavity 22 of steamer 20, and
water must be added to internal pot 10.
As shown in FIG. 5 to 7, in a cooking apparatus of another structure (i.e. the
second preferred embodiment), the water circulation system differs from that
in
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the first preferred embodiment in that no suction pump 40 is provided on flow
directing conduit 30.
Furthermore, the external wall of steamer 20 is connected to the mouth of
internal
pot 10 in a sealed connection. Specifically, the external wall of steamer 20
is
connected to the mouth of internal pot 10 in a connection sealed with first
sealing
ring 70. This effectively ensures that when pressure within the separating
cavity
between internal pot 10 and steamer 20 rises, steam can push water smoothly
into steamer 20 through flow directing conduit 30, and steam is prevented from
io escaping through the top of steamer 20 and the mouth of internal pot 10.
It should be noted that to ensure that the steam can push water smoothly into
steamer 20 through steamer suction tube 31 and water discharge tube 32 after
the pressure in the separating cavity between internal pot 10 and steamer 20
rises, the internal diameter of steamer suction tube 31 should be at least
0.5mm
and at most 20mm.
Further optionally, the internal diameter of steamer suction tube 31 is at
least
1.5mm and at most 12mm.
As shown in FIG. 8, the present invention provides a method for cooking rice
using a cooking apparatus, wherein different steps and elements of the
flowchart are represented by following references:
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Si: Place a certain amount of water into the internal pot
S2: Put in the steamer, and put rice into steamer
S3: Rice washing, water absorption
S4: Water in the internal pot is heated and boiled, and this status is
maintained up to the third preset time t3
S5: Water in the internal pot stops getting heated, and the contents of
the pot is held up to the fourth preset time t4
S6: Water in the internal pot is heated and boiled, and this status is
maintained up to the fifth preset time t5
S7: Water in the internal pot stops getting heated, and the contents of
the pot is held up to the sixth preset time t6
S8: Rice steaming and cooking is completed
S9: Water is heated up to the specified temperature Ti, and the status
is maintained up to the first preset time ti
El: Suction pump a: Closed
E2: PCB A: Activated
E3: Heating means b: Not powered
Cl : Maintained to second B: powered
preset time t2
C2: Cycle repeated Ni times C3: Cycle repeated N2 times
In this method, the cooking apparatus can be controlled using the method
described in the first specific embodiment, and the method for cooking rice
using
the cooking apparatus comprises the following steps: the rice washing step in
5 which water is drawn from internal pot 10 into steamer 20 using the water
circulation system to wash the rice contained within steamer 20, and
thereafter,
the water is directed into internal pot 10; the rice steaming step in which
heating
means 80 heats up internal pot 10.
io Hence, water is recycled and reused by producing steam to be used for
steaming
the rice from the water that was used to wash the rice. Additionally by
separating
the cooking and steaming processes using steamer 20, the starch and sugar
contents of the rice are reduced when they are lost from the rice and enter
the
rice water in internal pot 10. This lowers the sugar content of the cooked
rice and
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produces low glycemic index rice.
Before proceeding with rice washing, a certain amount of rice must be placed
within steamer 20, and a certain amount of water must be placed into internal
pot
10. The cooking apparatus then begins to operate at this point, with suction
pump
40 being activated to create a water circulation loop within the cooking
apparatus
by its suction action on the water in internal pot 10. The circulated water is
sprayed out from nozzle 33 located at the top of internal pot 10 and falls
onto the
rice contained within steamer 20. This washes the rice from top down and the
io rice also absorbs water in this process.
Optionally, during the rice washing step, rice washing is sustained up to the
second preset time t2, and t2 is at least 180s and at most 2400s.
Further optionally, in the rice washing step, the second preset time t2 is at
least
300s and at most 1800s.
It should be noted that a preheating step is performed between said rice
washing
and rice steaming steps, and said preheating step comprises heating the water
in internal pot 10 to a first preset temperature Ti and maintaining this up to
a first
preset time t1, after which, the operation of the water circulation system is
stopped.
Optionally, during the preheating step, the first preset temperature Ti is at
least
10 C and at most 100 C, and the first preset time t1 is at least 20s and at
most
600s.
Further optionally, the first preset temperature Ti is at least 50 C C and at
most
95 C, and the first preset time t1 is at least 30s and at most 400s.
To improve the taste of the cooked rice and to enhance the performance of the
cooking apparatus, the entire rice steaming step is divided into the
preliminary
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rice steaming stage and the final rice steaming stage according to sequence in
time.
It should be noted that during the preliminary rice steaming stage, heating
means
80 heats up internal pot 10 to the third preset time t3, after which, heating
means
80 stops operating and rice steaming is allowed to continue up to the fourth
preset
time t4, and the preliminary rice steaming stage is repeated Ni times. Hence,
through intermittent heating, this control method ensures that sufficient
steam is
produced by cooking apparatus to keep the rice in a state of high-temperature
io steaming, and boiling water will not mix with the foam from the rice
milk and is
prevented from rising and coming into contact with the rice. The requirements
on
the third preset time t3 is therefore comparatively stringent. Additionally,
water is
prevented from overheating and producing excessive amounts of steam that
could lead to leakage of water. Spillage is thereby prevented and energy
conserved.
Optionally, t3 is at least 3 seconds and at most 130 seconds, t4 is at least 3
seconds and at most 130 seconds, and Ni is at least 2 and at most 100.
.. Further optionally, Ni is at least 4 and at most 80.
It should be noted that in the final rice steaming stage, as rice steaming
progresses, water is constantly evaporated into steam, and the concentration
of
the rice milk in internal pot 10 increases continuously. Under heating, the
rice milk
is more prone to emerging from bearing cavity 22 of steamer 20 and coming into
contact with the rice. This will affect the moisture content of the rice and
compromise the GI reduction effect. Hence, after heating means 80 heats up
internal pot 10 to the fifth preset time t5, the operation of heating means 80
must
be stopped and the state must be maintained up to the sixth preset time t6, to
prevent generation of excessive amounts of steam, which can lead to water
leakage and the rice milk foam rising and coming into contact with the rice.
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Optionally, t5 is at least 3 seconds and at most 130 seconds, t6 is at least 3
seconds and at most 130 seconds, and N2 is at least 2 and at most 100.
Further optionally, N2 is at least 4 and at most 80.
In this specific embodiment, when the cooking apparatus is in the rice
steaming
step, the on and off times of heating means 80 need not be entirely regular.
This
means that the heating duration and stopping duration of heating means 80 can
be optimized based on the progress of cooking, such that these durations vary
between cycles.
Table 1 shows the specific method used in the rice steaming step of the
cooking
apparatus:
Table 1
Rice steaming step
No. of
times Preliminary rice steaming stage ..
Final rice steaming stage
t3 (seconds) t4 (seconds) t5
(seconds) t6 (seconds)
1 3 13 3 14
2 62 3 67 3
3 81 24 86 23
4 93 44 85 37
5 92 47 91 53
6 101 62 105 66
7 106 63 122 67
8 118 83 130 83
9 121 86
10 130 92
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Controlling the operation of the cooking apparatus using the method described
above allows the cooking apparatus to have a simpler structure, and produces
cooked rice with low glycemic index value, which will in turn increase the
level of
satisfaction among the users.
As shown in FIG. 9, the present invention further provides a second method for
cooking rice using the cooking apparatus, wherein different steps and
elements of the flowchart are represented by following references:
Si: Place a certain amount of water into the internal pot
S2: Put in the steamer, and put rice into steamer
S3: Rice washing, water absorption
S4: Water in the internal pot is heated and boiled, and this status is
maintained up to the third preset time t3
S5: Water in the internal pot stops getting heated, and the contents of
the pot is held up to the fourth preset time t4
S6: Water in the internal pot is heated and boiled, and this status is
maintained up to the fifth preset time t5
S7: Water in the internal pot stops getting heated, and the contents of
the pot is held up to the sixth preset time t6
S8: Rice steaming and cooking is completed
S9: Water is heated up to the specified temperature Ti, and the status
is maintained up to the first preset time ti
S10: Water is maintained at a constant temperature T2
S11: Water is heated up to the second preset temperature T2
El: Suction pump a: Closed
E2: PCB A: Activated
E3: Heating means b: Not powered
Cl : Maintained to second B: powered
preset time t2
C2: Cycle repeated Ni times C3: Cycle repeated N2 times
io For this second method, two different treatments that differ in the
sequence of
the preheating and rice washing steps are provided.
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The first treatment comprises: performing a preheating step before rice
washing,
wherein water in internal pot 10 is heated to a second preset temperature T2,
and
thereafter, the water circulation system of the rice washing step is
activated, and
this state is maintained this up to the second preset time t2.
5
The second type of treatment comprises: heating up the water contained within
internal pot 10 using heating means 80 as soon as the rice washing step is
activated, and when temperature of the water reaches a second preset
temperature T2, the rice washing step continues circulating up to a second
preset
io time t2.
In this way, by using water of a specific temperature to wash the rice and for
water
absorption, a substantial amount of starch and sugar can be washed away from
the rice, and cooked rice with low Glycemic index (sugar) is produced.
Optionally, in both treatments described above, during the preheating step, T2
is
at least 30 C and at most 95 C, and the second preset time t2 is at least 180s
and
at most 2400s.
Further optionally, T2 is at least 60 C and at most 80 C, and the second
preset
time t2 is at least 300s and at most 1800s.
The rice washing step can be followed by the rice steaming step. The rice
steaming step in this method is identical to that in the first method, and
hence the
description will not be repeated here.
The above are merely preferred embodiments, and are not intended to limit the
present invention.
