Note: Descriptions are shown in the official language in which they were submitted.
200~~ ~g
This invention relates to a uniformly heated
responsive cooker.
In modern living, various kinds of cookers are used,
e.g., electric cookers, automatic rice cookers, stew
cookers and so on. The majority are of a direct heating
type, that is, an inner pot is placed in an outer pot which
directly touches the heating source,, whereby the inner pot
is heated by the outer pot. In this way, food at the
bottom will be heated first and its temperature will rise
rapidly, whereas food at the upper part is heated slowly
and indirectly. Because of the non--uniform heating, food
at the bottom touching the heating ;>ource is heated too
quickly and consequently the nutrients are almost totally
destroyed in a short time. Also, the food at the bottom is
often charred or too tough, while food at the upper part is
not cooked enough. Consequently, the flavor of the food is
greatly reduced. Furthermore, if the food is required to
be simmered according to traditional. cooking methods, much
time is needed.
An object of the present invention is to provide a
uniformly heated responsive cooker including an inner and
outer pot, wherein the inner pot is airtightly removably
disposed in the outer pot, the bottom and outer wall of the
inner pot being spaced from the outer pot and forming a
closed heating space therebetween; whereby the pressure
existing in the heating space can be properly adjusted by
means of an exhalation valve means so that the food in the
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inner pot is uniformly entirely hearted by the thermal
energy and pressure in the outer poi=.
According to the above objects,. in a preferred
embodiment, this invention includes two sets of exhalation
valve means, one of which is composE~d of a pressure
regulating valve (or constant pressure valve), a safety
valve, a breathing valve and a cooling water auto-returning
valve and the other of which is composed of a two-way
venting valve.
Another object of the present invention is to provide
the above cooker, wherein pressure i.s held steady in the
heating space by the first exhalation valve means,
automatically, by temporarily and repeatedly discharging
the proper amount of thermal energy and pressure; after
each incident of pressure discharging movement, the food
temperature in the inner pot is responsively increased
until the thermal energy conduction barrier between the
heating space and the inner pot disappears, permitting the
thermal energy produced in the space to be directly
conducted to the inner pot and making the food in the inner
pot be surrounded by thermal energy in the space whereby
the food is heated and boiled entirely uniformly under same
temperature and pressure so as to maintain the original
taste and nutrition of food, and the cooker fully and
effectively utilizes thermal energy to save cooking time
and energy.
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In one embodiment of this invention, the pressure
limits 17 the exhalation valve means will be at the maximum
tolerated pressure of the pressure :regulating valve which
is less than or equal to that of the constant pressure
valve, while that of the pressure constant valve is less
than that of safety valve. Thus, not only can the
exhalation pressure be properly adjusted, but the safety of
the cooker is also ensured.
A further object of the presents invention is to
provide the above cooker, wherein during heating, steam
flows through the venting opening on a lower pot cap and
detours to a two-way venting valve of a second exhalation
valve means on an upper pot cap and is finally discharged
into the atmosphere, whereby the two-way venting valve can
ensure that the lower pressure steam which is generated is
not completely discharged into the air but is retained for
some time between the lower pot cap and the inner pot to
thereby enhance the heating effect: when the heating is
terminated, steam will be exhaled by the two-way venting
valve of second, exhalation valve means for a finite time
and finally stopped so that a finite amount of steam and
heat can be retained in the inner pot to closely steam the
food, and then external air will flow back to said inner
pot at the proper time to achieve a balance between the
pressure inside the inner pot and the external pressure to
allow easy opening of outer cover.
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To best understand the present invention, lease refer
to the following description and accompanying drawings
wherein:
FIG. 1 is a longitudinal sectional view of a typical
embodiment of this invention;
FIG. 2 is a perspective exploded view of one of
embodiments of the exhalation valve means of this
invention;
FIG. 2A is a sectional view of the casing of the
pressure regulating valve thereo f
FIG. 3 is a longitudinal sectional view of the cooling
water auto-returning valve of this invention;
FIG. 4 is an assembled longitudinal sectional view of
the exhalation valve means shown in FIG. 2 of this
invention;
FIG. 5A is a longitudinal sectional view, showing the
constant pressure valve thereof, disposed on the ring
member in the closed state
FIG. 5B is a longitudinal sectional view, showing
another embodiment of the constant pressure valve of this
invention, disposed on the ring member in the closed state
FIG. 5C is a longitudinal sectional view, showing
another embodiment of the breathing 'valve of this
invention, disposed on the ring member in the open state
FIG. 6A is a longitudinal sectional view, showing the
constant pressure valve of FIG. SA, :raised and opened by
the steam;
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FIG. 6B is a longitudinal sectional view, showing the
constant pressure valve of FIG. 5B :in the open state;
FIG. 6C is a longitudinal sectional view, showing the
breathing valve of FIG. 5C in the closed state;
FIG. 7 is a perspective view oi' the drain valve and
drain pipe of the present invention;'
FIG. 8 is an exploded, partial7_y sectional view of the
outer pot, inner pot and ring member of this invention;
FIG. 9 is a top view of the ring member of this
invention;
FIG. 10 is a longitudinal sectional view of a second
embodiment of the invention;
FIGS. 11 and 12 are two exploded views respectively
illustrating two forms of a third embodiment thereof;
FIGS. 13 and 14 show two embodiments of the exhalation
valve means of this invention, in which FIG. 13 shows the
exhalation valve means mounted on a pot cover of the outer
pot while FIG. 14 shows the exhalation valve means mounted
on the pot wall thereof;
FIG. 15 is a longitudinal sectional view of a fourth
embodiment of this invention;
FIGS. 16 to 18 show different ways to mount the
exhalation valve means respectively inside and outside the
cooker of this inventions and
FIG. 19 is a longitudinal sectional view of a fifth
embodiment of the invention.
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For the convenience of description, the same or
relevant elements in different embodiments are denoted by
same reference numerals.
The present invention is primarily characterized in
that the inner pot in which the food is stewed is not
directly in contact with the heating source and the outer
pot, and that the exhalation valve means are applied to
regulate and set the steam pressure between the inner and
outer pots to a predetermined value, whereby the inner pot
is entirely uniformly heated under even temperature and
pressure conditions for cooking the food. In such manner,
the food can be thoroughly~and perfectly stewed and cooked.
For easy description and understanding, the first
embodiment of this invention will be described in detail as
a major matter of this invention as follows:
Please refer to FIG. 1 showing a longitudinal
sectional view of first embodiment of this invention, in
which there is a shallow depression 2 formed on the bottom
of an outer pot 1 for containing water. A drain valve 4
and a drain pipe 43 are disposed on one side of the shallow
depression 2 for drainage and cleaning of the depression 2.
A heater 5 and a temperature-control breaker 6 are
installed respectively on and beside the shallow depression
2. Housing 7 and an outer cover 8 are mounted outside the
outer pot 1 for decoration.
An upper edge 10 of an inner pot 9 is formed with
multi-stepped annular flanges to which a pot cap assembly
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18 is fitted. Several projections 11 are further formed on
the wall of inner pot 9 (see FIGS. 1 and 8). A ring member
12 including a ring packing 15 is installed and screwed on
upper edge of outer pot 1 by means o f several screws 13.
Several recesses 14 are formed along inner periphery of
ring member 12 (see FIG. 9). Ring packing 15 has a V-
shaped cross section and is fitted on the inner periphery
of ring member 12. Moreover, a number of vent holes 16 are
formed on ring member 12 (see FIGS. 1, 8 and 9) for
installation of a number of constant: pressure valves 17.
When projections 11 of inner pot 1 (see FIG. 8) are aligned
with the recesses 14 of ring member 12, the inner pot can
be lowered with its upper edge 10 closely opposed to the
ring packing 15. In this position, the inner pot 9 can
then be rotated to separate the projections 11 and recesses
14, thus being secured on the ring member 12. Neither the
wall nor base of inner pot 9 will touch the outer pot,
forming a first space 100 therebetween.
A pot cap assembly 18 is comprised of an upper cap 19
and a lower cap 20 and is fitted to the inner center of
outer cover 8. On the lower pot cap 20 is disposed a vent
hole 21. An airtight ring gasket 22 with V-shaped cross
section is fitted to circumference of the upper pot cap 19,
preventing air or steam leakage. Through the outer cover 8
and upper pot cap 19 is disposed a two-way venting valve
23. When the outer cover 8 is put onto the cooker, the
upper and lower pot caps 19, 20 both fit on multi-stepped
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flange of upper edge of the inner pot 9, whereby, a second
space 200 is formed between the lower pot cap 20 and food
in the inner pot 9, and a third spat:e 300 is formed between
the upper pot cap 19 and the lower x>ot cap 20. The second
and third spaces 200, 300 are in limited communication with
each other through the vent hole 21.
A pivot 81 acts as an active joint for outer cover 8
such that when outer cover 8 is closed, it is locked by a
holdfast 82. Both upper pot cap 19 and lower pot cap 20
fit on the multi-stepped flange of upper edge of the inner
to 9. A buffer pad 181 is disposed on the center of outer
cover 8, whereby when the outer cover is closed, the pad is
pressed and the lower pot cap 20 is pushed by a reaction
elastic force of the buffer pad 181 so that in case the
pressure is too high, and vent hole 21 cannot sufficiently
exhale the stem, the lower pot cap 20 will be raised by
means of elasticity of the buffer pad 181 and the steam
will be exhaled through periphery of the lower pot cap 20
to the upper pot cap 19, and then through the two-way
venting valve 23 into atmosphere so .as to form a roundabout
path of thermal energy. In this way, the thermal energy
stays between the inner pot and the pot cap assembly for a
longer time to be fully utilized, thus saving energy.
In one of the embodiments of the exhalation valve
means 3, the valve means is installed outside the housing 7
and communicates with the space between inner and outer
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pots via a tube 25 which pierces through the walls of
housing 7 and outer pot 1.
Referring to FIG. 2 showing an exploded view of the
exhalation valve means 3, a casing 30 together with a
packing (not shown) are tightly associated with an upper
cover 31 by screws 32, forming a closed space. A circular
groove 33 is formed at the bottom of: casing 30 receiving a
cooling water auto-returning valve ~t4 (shown in FIG. 3).
Three holes are punched on upper cover 31 for respectively
receiving a safety valve 35, a breathing valve 36 and a
pressure regulating valve 37. Safety valve 35 consists of
a hollow cylinder 351 and a gravitation cap 352. On the
center of gravitation cap 352 is formed a circular concave
portion slightly larger than the hollow cylinder 351. When
the pressure in the space between the inner and outer pots
is relieved through constant pressure valve 17 and/or
pressure regulating valve 37, but th.e steam still is not
properly exhaled in time and the remaining pressure is
still larger than weight of gravitation cap 352, the steam
will push the cap 352 upward and escape through the gap,
thereby ensuring safety. Breathing valve 36 is composed of
a base 361, a screw lid 362 having an elastic plug 363
corked in central hole thereof, and a movable valve stem
364 fitted in a central hole 365 of the elastic plug 363.
The central hole 365 of elastic plug 363 is slightly
larger than a central cylinder portion 366 but smaller than
the base portion 367 of movable valve stem 364. When first
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heated, steam pressure is not large; steam mainly escapes
through the gap between cylinder portion 366 and wall of
central hole 365. As heating proceeds, the base portion
367 is pushed up by steam, and hence the elastic plug 363
is pressed tightly against the base portion 367 so that
steam can not go through the breathing valve and must be
discharged through other valves.
The pressure regulating valve 37 consists of a base
371, a plug 372, a spring 373, a pad. 374, a movable member
375, a guiding member 376, a casing 377, a rotary disk 378
and a scale ring 379. The base 371 of pressure regulating
valve 37 penetrates the upper cover 31 and is mounted
thereon so as to communicate with the space in casing 30.
Plug 372 is a hollow body having a front cone portion
formed with several exhalation holes 3721, and a small
diameter tail projection 3722. Pad 374 is hollow and has a
tail projection 3741. Disposed between plug 372 and pad
374 is spring 373. The two protrusions 3751 outside
movable member 375 just fit two helical grooves 3761 formed
on guiding member 376 and can move t:herealong. Two inner
straight slide channels 3771 formed ~on the inner surface of
fixing casing 377 (see FIG. 2A) allows the vertical motion
of movable member 375 with its protrusions 3751 sliding
along the slide channels 3771. Installed inside the casing
377 are plug 372, spring 373, pad 374, a movable member 375
and guiding member 376. The assembled parts are then
screwed on base 371 via thread of fi:King casing 377, and
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protrude beyond the top of guiding member 376. Scale ring
379 and rotary disk 378 are then screwed on the guiding
member 376. Rotation of rotary disk 378 turns guiding
member 376, making movable member 3'75 move up or down along
the channels 3771 of casing 377 because of mutual
interaction between protrusions 3751 of movable member 375
and helical grooves 3761 of guiding member 376 (please see
FIGS. 2A and 4). In this way, the compression force of the
spring is adjusted to vary the pressure limit of the plug
372.
Referring to FIG. 2A, which shows sectional view of
the fixing casing 377 of the pressure regulating valve, .it
is seen that two vertical slide charnels 3771 are formed
therein for sliding of movable member 375.
Referring to the cooling water auto-returning valve in
FIG. 3, a communicating tube 25 inserted in a hole punched
on outer pot 1 is fixed by a nut 251. Tube 25, piercing
outer pot 1 and housing 7, is connecaed to cooling water
auto-returning valve 34 which has a horizontally movable
plug 341 at its front end. There are several through holes
3411 at the head of movable plug 341 which can horizontally
move freely inside the valve 34. The inner diameter of the
front end of the valve is approximately equal to that of
plug 341, and they are loosely matched. A vertically
protruding spherical plug 342 is provided having a ball 344
which blocks an exit because of its weight. Therefore, the
movable plug 341 and spherical plug 342 become one way
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valves. When the steam generated in outer pot 1 passes
through tube 25 and then into cooling water auto-returning
valve 34, it pushes movable plug 34:1 towards outlet 343 to
block the same so that steam cannot escape through this
plug, and ball 344 is thus pushed upward by the steam which
escapes through injection opening 345 of spherical plug
into casing 30. When meeting the anabient casing wall,
steam condenses and flows back into casing 30. In this
way, no steam and water will be sprayed when pressure is
relieved. When heating is stopped, the pressure between
the inner and outer pots reduces, and the pressure in
casing 30 gradually disappears. They weight of ball 344
causes it to fall down and block the: exit of spherical plug
342. Condensed water due to pressure difference pushes the
movable plug 341 to open the outlet 343 and flow back to
the shallow depression 2 of outer pot 1 through holes 3411
of plug 341 until equilibrium of pressure is achieved.
Through this, the cooling water recycles automatically.
Referring to the sectional view of the valve set of
this invention in FIG. 4, generated steam passes through
communicating tube 25 to spherical plug 342 of cooling
water auto-returning valve into casing 30. During the
initial low pressure period, steam escapes through the gap
between elastic plug 363 and movable stem 364 of breathing
valve 36. As the heating proceeds and the pressure rises,
stem 364 of breathing valve 36 is entirely pushed up to
block the hole 365 of elastic plug 303, preventing steam
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exhalation and leaving only the constant pressure valve
(disposed on ring member) and pressure regulating valve
available for exhalation. When the pressure is larger than
that given to plug 372 by spring 37:3, steam will push plug
372 open and discharge. For even larger pressures, steam
will discharge through safety valve 35 to ensure safety of
this invention.
Referring to constant pressure valve 17 in FIG. 5A, it
is composed of a casing body 171, a spring 172, a plug 173
and a threaded seat 174. There are several holes 175
formed at the front portion of plug 173. Pressurized by
spring 172, plug 173 is opposed against the threaded seat
174 so that the space between inner and outer pots is
isolated from surrounding.
Referring to FIG. 6A, if the pressing force of steam
pressure is greater than the elastic: force of spring, plug
173 is pushed open and excessive steam discharges through
holes 175.
To make the valves of this invention interchangeable
and facilitate procedure of processing and molding, and to
decrease amount of stored spare valves, the aforesaid
constant pressure valve can be manufactured with the
structure as shown in FIGS. 5B and 6B. In this embodiment,
the plug members of the safety valve, constant pressure
valve and breathing valve are unified in shape. As shown
in the drawings, the plug 173 is formed with a hollow conic
head and a hollow cylinder body. Moreover, multiple vent
13
200~~ ~9
holes 175 are formed between the hollow conic head and
cylinder body at equal angle to one another. The cylinder
body is designed such that the diamE~ter permits the plug
173 to freely slide in casing 171. In particular, the
constant pressure valve includes a hollow casing 171 having
an inlet 176 and an outlet 177, a tapered passage 178
formed on the inner wall of this inlet 176, a hollow plug
body 173 movably disposed in the hollow casing 171 having a
conic head 175 near the inlet 176 and a cylinder body near
the outlet, multiple vent holes formed between the conic
head and cylinder body, a spring 172 disposed between the
cylinder body of the hollow plug 173 and outlet 177 of
casing 171, a hollow threaded seat 174 screwed on one end
of the casing 171 to limit motion of the hollow plug within
the casing. In the normal state, the spring 172 abuts
against the hollow plug 173, making the conic head thereof
opposed against the tapered passage 178 of inlet of the
hollow casing so as to block the passage. Thus, the
constant pressure valve will be closed under the preset
compression force of the spring. When the pressure of
fluid at the inlet of the casing is greater than the action
force of the spring, the hollow plug is raised up to
compress the spring, making the conic head of the plug
separate from the tapered passage so that the fluid can
flow through the inlet and multiple vent holes of the
hollow plug and discharge from the outlet 177 of the casing
171. Therefore, the casing 171 an bE~ assembled with the
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plug 173, spring 172 and threaded sE~at 174 to form constant
pressure valve. When the spring 172 is replaced with a
spring having larger elastic force, the constant pressure
valve will become a safety valve 35 with a function
identical to aforesaid embodiment.
Moreover, if the spring of constant pressure valve is
eliminated and the plug 173 is reversely disposed in the
casing 171, as shown in FIGS. 5C, 6C, then the valve will
soon become a breathing valve 36. ~~t initial heating
stage, the steam pressure is not so large, and the steam
can go into the hollow plug through the inlet of the
casing, and flow through multiple vent holes of the plug to
discharge from outlet of the casing. When the pressure of
the steam increases, the plug is raised by the steam
pressure to move along inner wall of the casing, whereby
the conic head of the plug contacts the tapered passage and
blocks the same so as to prevent the steam from exhalation.
When the raising force of the steam is smaller than weight
of the plug body, the plug will drop down again, separating
the conic head thereof from the tapered passage to form a
free passage, thereby permitting the external gas to go
therethrough, and the breathing function of the breathing
valve is thus performed. Thereby, the valve parts of this
invention are improved to facilitate the manufacturing
technique thereof and easy management can be achieved.
With reference to the drain valve and drain pipe in
FIG. 7, drain valve 4 is connected t~o a rod 41 which
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protrudes beyond housing 7 and has a rotary switch 42 at
its protruding end. A drain pipe 4,3 is screwed to one end
of drain valve 4 for drainage while the other end of drain
valve 4 is fixed to lowest point of shallow depression 2 of
outer pot 1.
In FIG. 8, ring member 12 is anchored on the upper
edge of outer pot 1 by means of rind packing with V-shaped
cross section (not shown in FIG. 8) and several screws.
The upper edge of inner pot 9 is formed with a multi-
stepped annular flange. The pot wall thereof is formed
with several projections 11 which ca.n fit into and pass
through recesses 14 of ring member 12 (see FIG. 9) such
that inner pot 9 can be associated with and supported by
ring member 12. In this way, the inner pot hangs above the
outer pot without touching the bottom and wall thereof,
forming a well-closed space for heating in the event that
water is contained and heated in the depression of outer
pot.
Referring to the ring member in FIG. 9, several
recesses 14 are formed along the inner periphery thereof
corresponding to projections of inner pot and vent holes
16, wherein the vent holes are suitable for installation of
constant pressure valves 17. In a preferred embodiment, no
constant pressure valve 17 is disposed and the vent holes
16 are not disposed, as shown in FIG. 16. Of course the
vent holes 17 can still remain without installation of
constant pressure valve, making the :First space 100
16
2007 19
communicated with third space 300, as shown in FIG. 15.
This will be further described in detail hereinafter.
Some water is added to the shallow depression in the
outer pot and food is placed in the inner pot which is then
put into central hole of the ring member such that
projections 11 of inner pot just fit: and pass through the
recesses 14 and the inner pot is engaged with the ring
member. In this position, the lower side of the upper edge
of the inner pot touches the V-shaped ring packing,
permitting the inner pot to rotate thereon. When the pot
cap assembly is installed, the upper edge of the inner pot
is pressed against the V-shaped packing 22 of the upper pot
cap, forming the third heating space 300. Meanwhile, the
first heating space 100 is formed between inner and outer
pots, which can be communicated with casing 30 of exhala-
tion valve means 3 by means of a communicating tube 25.
When the bottom of the outer pot is heated and steam
is gradually generated, the heating space between the inner
and outer pots is filled with a mixture of hot steam and
room temperature air. The mixture flows through the
communicating pipe into the cooling water auto-returning
valve of the valve set. The vertical spherical plug will
be blocked by the ball due to ball weight since the steam
is too weak to push it open, and thus horizontal movable
plug is pushed forward by steam and again blocks the outlet
of the steam. As more steam is generated so that it has
sufficient power to push the ball up, some gas escapes
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through the injection spout of the spherical plug into
casing 30 of exhalation valve means 3. Among exhalation
valve means, the movable steam of the breathing valve
requires the least pressure for relieving, and therefore
the aforesaid hot steam and room temperature air mixture
can be exhaled properly through breathing valve.
As the heating proceeds and they amount of steam
increases, movable stem is pushed by the steam and blocks
the breathing valve. At this moment., the V-shaped ring
packing between inner pot and ring member suffering the
pressing of steam at its mouth opens gradually, finally
touching more closely the upper edge of inner pot, and
hence forming a perfect closed heating space.
As more steam is generated in further heating, steam
fills up the whole space between the inner and outer pots,
and uniformly transfers heat to the inner pot bottom and
wall. According to heat conduction principles, the
temperature difference between high temperature steam and
cold food in inner pot is great and it is not likely to
reach an isothermal state in an instant because of the heat
barrier. Therefore, the heat cannot be immediately
transferred into the inner pot, and .as heating proceeds,
the heat conducting rate cannot catch up with steam
generation rate, subsequently causing an increase of
pressure which can be adjusted by discharging some steam
through the constant pressure valve on the ring member or
the pressure regulating valve on the exhalation valve means
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3. Steam exhaled through the constant pressure valve
passes through gap 71 between the outer cover and the
housing into the atmosphere (Gap 71 exists between the
outer cover and housing when they are associated.).
In this way, the steam pressure in the first space 100
can be maintained steady. Before the steam pressure rises
to the exhalation level, all of the heat energy generated
is conducted repeatedly to the inner- pot to raise the food
temperature. This action is repeated again and again until
the steam pressure reaches exhalatic>n level. In other
words, although the short cycle of pressure relieving is
repeated, the temperature of the food and the inner pot
will rise in every steam exhalation.
When the food and inner pot temperatures rise
gradually, the heat conduction barrier disappears. From
this moment on, heat is directly conducted to the inner pot
and thus the food, giving the greatest heating response.
Steam which is generated in the inner pot during
boiling flows through the vent hole opening of lower pot
cap, and detours to the breathing valve on the upper pot
cap, and is finally discharged into the atmosphere. The
two-way venting valve can ensure that the lower pressure
steam which is generated is not completely discharged into
air but is retained for some time between the lower pot cap
and the inner pot, thus enhancing the heating effect. As
more steam is generated which cannot escape from inner pot,
it presses the V-shaped mouth of the V-shaped ring packing
19
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on the outer boundary of the upper pot cap, forming a tight
contact between the packing and uppE~r pot cap and upper
edge of inner pot, forming a perfect. closed heating space.
When food in the inner pot is heated and excessive
steam is generated, the steam will push the breathing valve
open and discharge outward. If the steam in lower pot cap
is too much, then the buffer pad of cap assembly will be
raised by the steam, permitting the same to escape through
periphery of lower pot cap into the third space between
upper and lower pot caps, and then discharge to atmosphere
through the two-way venting valve 2?~.
When heating is terminated, steam will be exhaled by
two-way venting valve for a certain time. This action will
slow down and finally stop so that a. certain amount of
steam and heat can be retained between the inner pot and
pot caps to closely steam food. Atmospheric air will
slowly flow back into inner pot through said two-way
venting valve 23, thereby balancing the pressures existing
on two sides of pot cap assembly for easy opening of outer
cover.
On termination of heating, the two-way venting valve
can remain in the closed state for some time (due to the
small pressure limit), keeping some steam in first space
for further closely steaming the inner pot. When the
pressure between the inner and outer pots reduces, the
movable stem drops down, permitting external air to slowly
flow in through the gap.
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Moreover, the movable ball of :spherical plug of the
cooling water auto-returning valve drops down also due to
its weight after heating stops, thereby blocking the exit.
Condensed water compelled by inflowing air pushes the
horizontal movable plug open, and flows back to the shallow
depression of the outer pot. Thus, the problem of water
accumulation in valve casing of exhalation valve means 3 is
eliminated.
Because of the entire uniform and indirect heating by
steam and separation of inner pot from outer pot, every
part of food in inner pot can be evenly and entirely heated
and boiled under the same temperature and pressure by steam
heat conduction step by step. In addition, as food is
heated step by step, it fully absorbs the thermal energy
and its flavor and nutrition can be completely preserved.
Furthermore, because the steam is effectively used, cooking
time is shortened and energy is saved.
Please now further refer to FIGS. 10 to 19 for a
better understanding of other preferred embodiments of the
present invention.
FIG. 10 shows a longitudinal sectional view of a
second embodiment of this invention, wherein the inner pot
9 is hung above the outer pot 1. In this embodiment, the
inner pot is directly air-tightly supported in the outer
pot without using ring member. The upper externally
extending annular flange 110 of outer pot 1 is air-tightly
engaged with corresponding upper externally extending
21
A
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annular flange 101 of the inner pot, resulting in the inner
pot being spaced from the bottom and wall of the outer pot
to achieve the identical effect as the first embodiment.
In this embodiment, the safety valve 35, breathing valve 36
and pressure regulating valve 37 or constant pressure valve
17 are all disposed on the peripheral wall of the outer
pot, while the other fittings are the same as first
embodiment and will not be further described herein.
In FIGS. 11 and 12, a third embodiment of this
invention is shown, wherein by means of a perforated metal
heat-conducting pot 50 (as shown in FIG. 11) or a solid
metal heat-conducting pot 50A (as shown in FIG. 12), the
inner pot is hung above inside the outer pot, forming a
first space 100 between heat-conducting pot 50 or 50A and
outer pot 1. The inner pot 9 is sealedly fitted into the
heat-conducting pot and closely asso~~iated therewith,
whereby thermal energy in the first apace 100 can be
conducted to inner pot 9 through solid heat-conducting pot
50A or through vent holes 501 of the perforated heat-
conducting pot 50 to entirely and uniformly heat the food
contained in the inner pot at same tE~mperature and pressure
as performed in the above embodiments so as to achieve the
identical effect.
In FIGS. 13 and 14, two forms of installation of
exhalation valve are shown. FIG. 13 illustrates that the
breathing valve 36, safety valve 35 and pressure regulating
valve 37 (or constant pressure valve 17) are all disposed
22
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on the pot cap of the outer pot. F7fG. 14 illustrates these
valves mounted on the pot wall of the outer pot to achieve
same function as above-mentioned embodiment.
FIG. 15 shows a fourth embodiment of the present
invention, wherein the vent holes lEi of the ring member 12
are open without mounting any exhalation valve thereon,
making the first and third heating ~~paces communicating
with each other. The exhalation valves are all
alternatively disposed on the pot ca.p, making the inner pot
thoroughly surrounded by the first a.nd third heating spaces
to achieve the heating and cooking effect as above
described.
FIGS. 16 to 18 respectively show alternative
embodiments of the installation of the exhalation valves on
the cooker, wherein FIG. 16 shows that the ring member 12
is of sealed type, resulting in the first space being
isolated from the atmosphere and the safety valve 35,
breathing valve 36, constant pressure valve 17 or pressure
regulating valve 37 mounted on the pot wall of the outer
pot are used to adjust the steam pressure, while the other
parts are same as the above embodiments. FIG. 17 shows the
safety valve 35 and breathing valve 36 disposed on the ring
member 12, and the constant pressure valve 17 or pressure
regulating valve 37 mounted on the pot wall of the outer
pot. FIG. 18 shows the constant pressure valve 17 and
breathing valve 36 disposed on the rang member 12, while
the safety valve 35 is mounted on the pot wall of the outer
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20074 19
pot to also achieve the function as described in the above
embodiments.
Additionally, to meet the requirements of different
cooking temperature for different foods, temperature
control means 91, 92 can be further mounted as shown in
FIG. 19 in addition to the above-mentioned exhalation
valves. By means of cooperation of the exhalation valves
and temperature control means, the best accurate boiling
temperature can be precisely controlled as necessary to
keep the natural nutrients and flavors of various foods and
to acquire better cooking effect.
Since the heater, temperature control breaker or timer
mentioned above are all of conventional arts, they will not
be discussed herein.
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