Note: Descriptions are shown in the official language in which they were submitted.
CA 02707930 2012-07-23
MICROWAVE PRESSURE COOKER
FIELD OF INVENTION:
The present invention in general relates to the microwave compatible cooking
system to be used as home appliance for cooking foods and it more specifically
relates to pressure cooking system to be used inside a microwave oven for
cooking
food containing steam at a pressure above the ambient pressure. The microwave
pressure cooker described in this invention can be used to cook foods in
various
situations for domestic pressure cooking. This is a complete self contained
system
that can be used with any microwave oven provided with a chamber large enough
to
accommodate it.
BACKGROUND OF THE INVENTION :
Microwave ovens use microwave energy to heat or cook food in a fraction of
the time needed to cook with conventional ovens. Unlike conventional ovens, a
microwave oven heats food without applying the external heat i.e. any flame or
direct
heat sources. The microwaves readily pass through many materials, such as
glass,
most plastics, paper and china clay, with little or no effect. Generally,
these materials
are used for making utensils which can be used for cooking in a microwave
oven.
In microwave cooking, the metal utensils do not allow penetration of
microwaves to generate the heat energy required for cooking the food, and
thereby
cooking efficiency is greatly reduced. Further there is also possibilities of
damage for
the microwave oven due to the arc formation between the metallic utensils and
the
door of the oven and may also results in the discoloring of cooking food which
leads
to a hygienic problem.
Nowadays the use of number of microwave oven in public has grown at very
high rate. There has been an increase in demand for specially designed and
configured cooking vessels for use in microwave ovens to provide easy and
convenient way of preparing foods in microwave ovens. Many attempts have been
made in the manufacture of various types of cooking vessels, casserole dishes,
various types of bowls, pressure cookers for microwave and the like, to be
compatible with use in microwave ovens.
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PRIOR ART:
US patent no. 4796776 discloses a pressure cooker for use in microwave
ovens includes a microwave permeable bowl-shaped container, a microwave
permeable dome cover, and a steel locking ring permanently attached to the
cover
for maintaining the container and cover in fluid-tight seal during use. A
safety valve,
formed of flexible tubing, encounters a projection of the container and is
deformed
into a closed configuration responsive to movement of the cover, relative to
the
container, toward a locking position. A pressure regulator valve, consisting
of a metal
core surrounded by an elastically deformable casing, which is positioned over
a
pressure control opening in the cover to maintain a selected operating
pressure level
in the pressure cooker.
US patent no. 4853509 discloses a rice cooker for preparation of shaped
foods of rice in a microwave range is made of microwave permeable synthetic
resin
such as polypropylene and internally provided with mutually separate confined
spaces of a fixed capacity and adapted for accommodating rice with water. As
the
rice cooker containing uncooked rice with water is heated in the microwave
range,
compression acts on the boiled rice due to pressure contact of the boiled.
rice
swelled and water with walls defining the spaces and the boiled water is
automatically shaped in the spaces. Absence of direct contact of the rice with
user's
hand during the process enables preparation of shaped foods of rice such as
rice
balls without any keen pain and blemish on the hands.
US patent no. 5229563 discloses a pressure cooker and a process for making
the same, wherein the pressure cooker includes a pressure container for
accommodating food to be cooked, a cover for covering the container in an air-
tight
manner, a pressure control device for adjusting the internal pressure in the
container. The container or the cover or both are partly or wholly made of a
composite resin consisting essentially of polyphenylene sulfide resin and 30
wt.% to
50 wt.% glass fiber.
US patent no. 5310981 discloses a microwave cooker capable of cooking an
assortment of foods by a variety of methods while maintaining constant
pressure.
This pressure cooker boils and steams foods continuously without pressure
build up
and without the need to shut off the microwave oven. Food spattering and
spillage
are prevented by a unique internal baffle rib design and a mechanism that
releaseably locks the top cover. The top cover and inner cover of the pressure
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cooker have the same outer diameter and each have a plurality of vent holes or
apertures. Both the top cover and inner cover are positioned within container
and
each have a skirted edge. The skirted edges form an enclosure within the
container
member, specifically designed to obstruct and contain escaping food particles.
DISADVANTAGES OF RELATED ART :
The existing microwave pressure cookers have metal parts for restraining
structural changes. Moreover they have metal based deadweight pressure control
systems. It is advisable to restrict the use of metallic materials inside
microwave
ovens because metals reflect microwave and modify the pattern of microwave
distribution within the microwave chamber.
In addition, any sharp projections in the metal parts arising out of normal
handling during the lifetime of the cooker can cause sparking in the chamber.
Further, the mechanical attachment between the metal parts and the
polymeric parts is not perfect. This can lead to loosening of the said parts
during the
repeated thermal cycling which is common in normal use.
Existing microwave pressure cookers have various metallic parts like the use
of metal based dead weight pressure regulators assembly, metal locking ring,
metal
latching members etc. Further they also permit emission of foamy liquid into
the
microwave chamber when froth generating foods are cooked.
In most of the prior art, the pressure cookers for microwave oven which either
partially or wholly describes the apparatus of cooking system comprising
container
and cover that have been constructed using microwave compatible material.
Further
many attempts have been made in prior art to achieve a microwave compatible
pressure cooking system, but still suffers from drawbacks of using some
metallic
parts like metal springs, metallic ring, metallic core for dead weight
pressure
regulating system etc., which are more dangerous and have disadvantages.
SUMMARY:
In an aspect of the present invention is to provide a pressure cooker system
comprising of sub-assemblies, all of which are designed to be compatible with
microwave energy, provided with all required safety features for microwave
cooking.
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Further, the invention provides a light-weight, simple and attractive
microwave
compatible pressure cooker embedded with safety devices prescribed in
appropriate
standards.
It is another aspect of the invention to provide a simple, attractive and
light
weight pressure cooker in which all parts and subassemblies are made up of
materials that is compatible with microwave oven.
It is another aspect of the invention to provide a pressure cooker with an
improved pressure regulating safety device made of elastomeric material
without the
use of metallic parts and conventional dead weight device for regulating the
pressure
developed inside the cooker. It is attempted herein to provide a pressure
cooker
with an improved visual pressure indicating device made of elastomeric
material
without the use of metallic parts for indicating the pressure that developed
inside the
cooker. Yet another feature in the present invention is that it is provided
with a
specially designed visual pressure indicator which is capable of regulating
pressure
when the cooker is under pressure and which also relieves the excess pressure
in
case of any contingency leading to the pressure inside increasing abnormally
beyond the designed operating pressure.
It is further aspect of the present invention to provide a receptacle in the
central portion of the cover of pressure cooker provided with a removable
receptacle
cover to prevent the spattering of the froth of the cooking food along with
vapor when
the excess pressure from the cooker is ejected out during cooking operation.
It is further aspect of the present invention to provide a gasket offset
device
which works with an improved locking arrangement in the pressure cooker to
prevent
hazardous building up of pressure inside the container in the event of
improper
closing of the cover.
It is further aspect of the invention to provide an effective, easy and
convenient means of pressure seal for pressure cooker cover and container.
This cooking system is thus absolutely metal free and made of filled or
unfilled
polypropylene, delrin, polycarbonate or any polymer compatible with microwave
energy at a working temperature of 100 -125 C.
It is yet another aspect of the invention to provide a removable filter means
for
preventing the froth from clogging/choking the primary pressure regulator
means and
so disposed that if this is not fitted the pressure cooker cannot build
pressure within
the pressure cooker.
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Further aspect of the invention is to provide with an improved integral stop
lug
in the cover of the pressure cooker which prevents the overriding of the cover
beyond the fully closed position when disposed on the body of the pressure
cooker.
In accordance with an aspect of the present disclosure there is provided a
microwave pressure cooker formed with a container open at its top comprising
the
following: a cover with a gasket adapted for ledge interlock type sealing and
lug
locking engagement with said container to form an enclosure for pressure
cooking
with the container; a first and a second regulator opening means forming valve
openings through said cover; a primary deformable diaphragm type pressure
regulator means with slits formed therein adapted to be disposed on the first
regulator opening means, and which is responsive to the pressure in the
enclosure;
a secondary deformable pressure indicator cum regulator means adapted to be
disposed on the second regulator opening means formed on the cover and which
is
responsive to pressure in the enclosure; a push rod type gasket offset device
means
mounted on locking lug and an opening and closing aid of cover for releasably
maintaining said container and the cover in said sealing engagement responsive
to
disposition of gasket on the cover and the movement of said gasketed cover
relative
to said container to a lock position; and a filter adapted to be disposed
removably on
the first regulator opening means wherein: said primary pressure regulator
means is
a pressure responsive diaphragm, characterized in the non-metallic deformable
microwave permeable diaphragm type pressure regulators means, the diaphragm
adapted to be disposed on the cover of the cooker, said diaphragm having a
slit
made thereon and which diaphragm responds when encountering a pressure
increase within the container to change the slit into an open configuration
responsive to pressure development within the closed cooker enclosure, when
the
pressure is greater than a selected nominal working pressure of the cooker,
said
diaphragm further characterized in that it is generally a flat disc shaped
pressure
responsive member, adapted to be disposed in the hole of the receptacle type
regulator opening means formed on the cover of the cooker, said disc portion
including an outer cooperating upwardly and downwardly extending peripheral
protuberances as gripping means that engage fittingly a portion around the
regulator
opening means at the opposed sides of the opening hole respectively.
Thus, the present invention eliminates all metallic parts from the entire
system
and all of its sub-assemblies are made up of microwave compatible material.
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According to the present invention, the microwave compatible pressure
cooker is a
combination of a pressure cooker and a microwave compatible appliance. This
microwave pressure cooker is made-up of microwave compatible material like
polypropylene with the use of silicone for sealing and safety devices.
In this present invention, the pressure cooker for a microwave oven works on
the principle of normal pressure cooking like in a conventional cooker used on
a gas
stove so that the cooking time is less compared to time taken by non pressure
cooking inside the microwave oven.
According to the present invention, the microwave compatible pressure
cooker has specially designed safety devices like pressure regulating valve,
secondary safety devices and a gasket offset device. All these are made with
microwave compatible materials which facilitates in using this Microwave
Compatible
Pressure Cooker inside the microwave oven.
BRIEF DESCRIPTION OF DRAWINGS:
The invention will be more fully described with reference to the accompanying
drawings wherein,
Figure 1 depicts the top and side view of the container (1) assembled with
cover (2).
Figure 2 depicts the inside view of the container (1).
Figure 3(a), 3(b) depicts the top surface of the cover (2) showing the
recessed
integral receptacle for trapping any foam ejected from the inside.
Figure 4 depicts the elastomeric pressure regulator having a slit (11).
Figure 5 depicts the elastomeric visual pressure indicator-cum over pressure
relief
device with slit in H- shape of symmetric design
Figure 6 depicts the push rod of gasket offset device.
Figure 7 depicts the gasket offset device sub assembly fitted in the cover(2)
which
works in conjunction with the container lugs to prevent pressure build up
unless the
cooker is properly closed as designed.
Figure 8 depicts the inner surface of the cover (2) wherein the gasket (3) is
fitted to
the cover(2) along with locking lugs (4) and gasket offset device.
Figure 9 depicts the inner side of the cover (2) which has receptacle opening
means
(5a, 5b) of the cover (2) which further includes perforated material (24)
underneath
the cover.
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Figure 10 depicts the elastomeric visual pressure indicator-cum over pressure
relief
device with slit in H- shape of symmetric design.
Figure 11 depicts the elastomeric visual pressure indicator-cum-over pressure
relief
device without slit in H- shape of symmetric design.
Figure 12 depicts the elastomeric visual pressure indicator device with flat
central
circular diaphragm (17).
Figure 13 depicts the receptacle cover (6) and a lip (7) which is intended for
closing
the recessed integral receptacle in the top of the cover (2)
Figure 14 illustrates the detachable gasket offset device cover (30) with the
fixing
means (31).
Figure 15 depicts the grommet (32, 33) which is disposed within the holes (27
and
28).
DETAILED DESCRIPTION OF THE DRAWINGS:
In the figures the following reference numbers are used:
Component Component Description Found in
number figures
1 Container 1,2
2 Cover 1,3a,3b,8
3 Gasket 7,8
4 locking Lug 7,8, 2
4" opening/closing aid of the cover 8, 7
5a First regulator opening means 3(a) & 3(b)
5b Receptacle type first regulator opening means 3(a) & 3(b)
6 Receptable cover 13,1
7 Lip 13,1
8 Primary deformable Diaphragm type pressure 4
regulator means
9 Pressure responsive diaphragm 4
10 Second regulator opening means 3a, 3b
11 Slits in pressure diaphragm 4
12 Flat disc shaped pressure responsive member 4
13a Secondary deformable pressure indicator cum 11
regulator means
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13b Secondary deformable pressure indicator cum 12
regulator means
14 Non metallic non deformable core 10,11
15 Pressure responsive type casing 10, 11
16 Non metallic deformable H shaped body 12,5
17 Flat central circular diaphragm 12,5
18 Upper and Bottom circular edge type flanges 12,5
19a Secondary deformable pressure indicator cum 10
regulator means
19b Secondary deformable pressure indicator cum 5
regulator means
20 Slit in H shape secondary indicator cum regulator 10
21 Slit 5
22 Push rod type gasket offset device means 6,7, 8
23 Push rod 6,7
24 Filter 9
25 Perpendicular pin 9
26 Perpendicular pin 9
27 Hole under receptacle 8
28 Hole under receptacle 8
29 Chamfers on container 2
30 Gasket Offset Device cover 14,8
31 Screw for Gasket Offset Device cover 14,8
32,33 Grommets on holes 27 & 28 15,8
34 Stop lug 8
Figure 1 illustrates the essential features of the design exterior of the
cooker
container (1). The crucial elements are the ribs projecting from the surface
in a
designed pattern for facilitating grip and to improve necessary mechanical
strength.
The material of the container (1) and cover (2) can be unfilled or filled
polypropylene,
deirin, polycarbonate or any polymer compatible with microwave energy without
deterioration of properties and which can give satisfactory mechanical
performance
at a working temperature of 125 C with food.
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The cover (2) incorporates a band which merges with the opening/closing aid.
The unique top cover (2) is further strengthened with annular grooves and is
also
provided with projecting ribs along its inner surface to improve necessary
mechanical
strength.
The cover (2) has unique feature wherein the froth or vapour is collected in a
receptacle. The receptacle has a top cover (6) and a lip (7).
Figure 2 illustrates the design of the smooth inner surface of the
container(1)
which permits easy removal of cooked material and subsequent easy cleaning of
the
container(1) without leaving any residue, of cooked food. The rim of the said
container (1) has locking lugs (4) to engage with the cover (2).
Figure 3(a), 3(b) show the recessed integral receptacle (5b) in the top of the
cover(2). This receptacle is intended to trap any foam ejected from inside
through
the primary pressure regulator means (8). As visible in the illustration of
Figure 3(a)
and 3(b) the secondary regulator means (10) may be disposed on any portion of
the
cover (2) and is not restricted only to the
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positions illustrated in accompanying drawings with this application. The
position may be on any
portion of the cover but spaced away from the primary regulator.
As per the invention, there are two hole type regulator opening means(5a, 10)
provided
on the cover(2) into which diaphragm type pressure regulator means is
removably disposed.
The cover (2) of the microwave pressure cooker as per the invention shall have
a
receptacle type regulator opening means(5b) which has an open annular
cylindrical length of
enclosed receptacle body formed underneath the cover(2) as vapour striking
volume and formed
integral with the cover(2). The said receptacle body has a generally circular
opening (5a) or a
cutout at its bottom adapted for removably disposing the diaphragm type
pressure regulator
means (8), thereby forming an open cavity arrangement. This cavity is adapted
to be closed by
the receptacle cover (6) provided with a lip (7) or a protrusion at the
peripheral top edge so as to
form an opening in the said cavity arrangement. This is illustrated in Fig.
13.
Figure 4 shows the primary pressure regulator means (8) with a flat disc
shaped
pressure responsive member (12), which is removably disposed in the hole (5a)
of the
receptacle type regulator opening means (5b) formed on the cover (2) of the
cooker. The said
primary pressure regulator means (8) has a pressure responsive diaphragm (9),
characterized in
the non-metallic deformable microwave permeable diaphragm type pressure
regulator means.
The diaphragm(9) has a slit(11) which responds when encountering a pressure
increase within
the container to change the slit(11) into an open configuration responsive to
pressure
development within the closed cooker enclosure.
Figure 5, 10, 11 and 12 illustrates the secondary elastomeric pressure
regulator means.
The material of the primary and secondary pressure regulator can be silicon
rubber, fluoro
elastomer, or any other elastomer which can stand a working temperature of 125
C and which is
compatible with microwave energy without deterioration of properties.
Figure 5 shows the elastomeric pressure regulator means(19b) which has a non-
metallic
deformable 'H' shaped body(16) formed with a flat central circular
diaphragm(17) in the mid
portion of the tubular cylinder body, with two extreme upper and bottom
circular edge type
flanges(18) forming outwardly extending lip. The flat central circular
diaphragm has a slit (21).
This regulator is unique in the sense that it can be disposed on the cover in
either direction.
Figure 10 shows the elastomeric secondary integral indicator cum pressure
regulator
means(19a) which has a non-metallic non-deformable core(14) projecting from
the bottom of a
pressure responsive elastically deformable type casing (15). The said core(14)
has a slit(20)
formed therein at its distal tip in closed configuration, such that the
slit(20) changing to open
configuration under the effect of pressure applied on the casing, disposed
within the closed
cooker enclosure.
Figure 11 shows the elastomeric secondary integral indicator cum pressure
regulator
means(13a) which has a non-metallic non-deformable core(14) projecting from
the bottom of a
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CA 02707930 2012-07-23
pressure responsive elastically deformable type casing (15). This pressure
regulator is designed without a slit.
Figure 12 shows the elastomeric secondary pressure indicator cum regulator
means(13b) which has a non-metallic deformable `H' shaped body(16) formed with
a flat
central circular diaphragm(17) in the mid portion of the tubular cylinder
body, with two
extreme upper and bottom circular edge type flanges(18) forming outwardly
extending
lip. This pressure regulator is also designed without a slit. This regulator
is unique in the
sense that it can be disposed on the cover in either direction.
Figure 6 depicts the free sliding push rod(23) of gasket offset device (22).
The
free sliding push rod(23) and the gasket offset device (22) is generally made
up of
microwave permeable material.
Figure 7 depicts the gasket offset device sub assembly fitted in the cover(2)
which shows the cover gasket (3), disposed on the cover rim. The said gasket
offset
assembly works in conjunction with the container lugs to prevent pressure
build up
unless the cooker is properly closed as designed.
Figure 8 depicts the inner surface of the cover (2) wherein the gasket (3) is
fitted
to the cover(2) along with locking lugs (4), opening/closing aid (4") and
gasket offset
device(22).
Figure 14 illustrates the detachable gasket offset device (30) adapted for
fitting
with the fixing means (31) and are generally made up of microwave permeable
material.
Figure 9 illustrates the inner side of the cover (2) which has the first
regulator
opening means (5b with 5a) which further includes a filter (24) ) which is
generally made
up of microwave permeable material and comprises of atleast a perforated
material
underneath the cover, covering the hole (5b) by means of perpendicular pin
(25, 26).
Each pin is removably positioned within a hole (27 , 28) shown in Fig. 8 and
each hole
is provided with a grommet (32 , 33) shown in Fig. 15 which is adapted to
receive the
perpendicular pin (25, 26) into the hole fittingly.
Figure 15 illustrates the shape of the grommet (32, 33) which is generally
made
up of microwave permeable material, and is disposed in a manner such that the
cylindrical portion is well within the holes (27, 28) and having circular
flanges at either
end to spread around the hole to form a locking collar at either end and is
adapted to
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receive the perpendicular pin (25, 26) therein within.
Figure 13 shows the receptacle cover (6) and a lip (7) which is intended for
closing the recessed integral receptacle in the top of the cover (2).
The present invention relates to a microwave pressure cooker consisting of a
container (1) and a cover (2). The cover with a gasket(3) is adapted for ledge
interlock
type sealing and lug locking engagement with the said container(1) to form an
enclosure
for microwave pressure cooking.
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The container (1) of the cooker has ribs formed on the outer surface to
facilitate grip and
easy handling. These ribs act as thermal offset which minimize the heat felt
when the cooker is
taken out of the microwave oven after cooking and also provide mechanical
strength to the
cooker. Further, the bottom of the container (1) also has ribs to ensure
strength and stability.
The rim of the container is provided with a pair of chamfer and lugs (4)
aiding to lock the
container and the cover.
The cover (2) is incorporated with a band which merges with a pair of
opening/closing
aid (4") that coincides with the chamfer of the container. The cover is
further strengthened with
annular grooves. The cover(2) has a unique feature wherein the froth or vapour
produced during
cooking is collected in a receptacle. The receptacle has a top cover (6) and a
lip (7).
The inner surface of the cover(2) has matching locking lugs (4) along the rim
cooperating
with the lugs of the container (1). The flexible deformable lug gasket is
mounted along the wall
of locking lug of the cover. The said cover gasket (3) is generally V shaped
in cross section. The
said container (1) is further adapted for additional interlock with the cover
(2) with the pair of
chamfer formed on two portions diametrically opposite on the inner rim of the
container top
edge, each of the chamfer portion corresponding to the span of the movable
pushrod (23) of the
gasket offset device (22).
The material of the container (1) and the cover(2) can be unfilled or filled
polypropylene,
delrin, polycarbonate or any polymer compatible with microwave energy without
deterioration of
properties and can give satisfactory mechanical performance at a working
temperature of 1250 C
with food.
The uniqueness of this invention lies on the characteristics of the various
pressure
regulator means and gasket offset device disposed on the cover.
This microwave compatible pressure cooker has specially designed safety
devices like
primary pressure regulating means (8), secondary pressure indicator cum
regulator
means(13a,13b 19a, 19b) and a gasket offset device (22). All these are made
with non-metallic
deformable, microwave compatible materials.
The cover comprises of a first and a second regulator opening means (5b with
5a and
10) forming valve openings for disposing various pressure regulator means
which can operate at
different thresholds.
The first receptacle type regulator opening means(5b) is an open annular
cylindrical
length of enclosed receptacle body formed underneath the cover(2) for
collecting the discharge
vapour of a predetermined volume. The said enclosed receptacle body is
embedded with the
cover (2). The said receptacle body has a circular opening (5a) or a cutout at
its bottom adapted
for removably disposing the primary diaphragm type pressure regulator means
(8), thereby
forming a open cavity arrangement. This cavity is adapted to be closed by the
receptacle cover
(6) provided with a lip (7) or a protrusion at the peripheral top edge so as
to form an opening in
the said cavity arrangement. The receptacle cover(6) has a smooth dome like
structure in its
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CA 02707930 2010-06-22
inner surface for deflecting the steam ejecting from the open slit(11) of the
pressure regulator
radially around and within the receptacle cavity arrangement. Further, the
receptacle cover (6)
shall have atleast one cone type projection in its inner surface for
deflecting the steam radially
and uniformly into the receptacle cavity arrangement.
The said primary pressure regulating means (8) consists of a pressure
responsive
diaphragm (9) having a slit(11) and a flat disc shaped pressure responsive
member(12). The
said flat disc portion includes an outer cooperating upwardly and downwardly
extending
peripheral protuberances as gripping means. This gripping means facilitates to
precisely dispose
the primary pressure regulating means around the regulator opening means at
the opposed
sides of the opening hole (5a).
When there is a pressure increase greater than the selected nominal working
pressure
(0.25 Kgs / sqcm) of the cooker within the cooker enclosure, the slit(11) of
primary pressure
regulating means (8) attains an open configuration. Alternately, when the
pressure decreases
below nominal working pressure, the primary pressure regulator means is
adapted to reset the
slit into closed configuration.
The said first regulator opening means (5b with 5a) has a filter (24)
comprising of atleast
a perforated material underneath the cover, covering the hole (5b) at the
outside bottom of the
receptacle by means of perpendicular pin (25, 26). The filter (24) is a flat
circular shaped plate
type perforated material held by two diametrically disposed perpendicular pin
(25,26) in the
corresponding holes (28 & 27) formed on the bottom surface of the receptacle
type regulator
opening means. Each pin is removably positioned within a hole (27 , 28) and
each hole is
provided with a grommet (32 , 33) which is adapted to receive the
perpendicular pin (25, 26)
and are open to atmosphere, thereby ordinarily preventing the pressure
building within the
enclosure for the pressure cooking until the filter (24) is mounted so as to
engagingly fit the pins
(25,26) into corresponding holes (28 & 27) containing the grommet(32, 33).
As per the invention, the said secondary pressure regulator shall be any one
of the four
types of regulator means (19b,19a,13a and 13b) illustrated in figures
5,10,11and 12
respectively. The secondary pressure regulator is removably disposed on the
hole (10) formed
on the cover (2).
The four types of elastomeric secondary pressure regulators mentioned above
perform
three distinct functions:
1) They act as a visual pressure indicator, indicating the pressure inside the
cooker.
2) They also act as a safety device which releases the excess pressure
(a) when there is an excess pressure of around 0.5 kg / sqcm which is more
than the operating pressure around 0.25 Kgs / sqcm.
(b) or in case of pressure regulator failing to operate for various reasons;
3) They also act as blow off device in case of excess pressure accumulation.
CA 02707930 2010-06-22
Among the four types of secondary pressure indicator cum regulator means 19a
and 19b
are designed with slits to release pressure, whereas 13a and 13b are designed
without slits to
act at different levels of operating thresholds.
The secondary pressure indicator cum regulator means 13b (Fig 12) and 19b (Fig
5) are
elastomeric pressure regulator which have a non-metallic deformable 'H' shaped
body(16)
formed with a flat central circular diaphragm(17) in the mid portion of the
tubular cylinder body.
The tubular cylindrical body has two extreme upper and bottom circular edge
type flanges(18)
forming outwardly extending lip. The protruding edge of the said lip sits on
the hole of the
pressure regulator opening means (10) formed on the cover (2) of the cooker.
They are
designed symmetrically and hence unique in the sense that it can be disposed
on the cover in
either direction.
The central flat circular diaphragm (17) in the secondary pressure indicator
cum
regulator 19b has a slit (21) formed in the centre of the diaphragm. From
closed configuration
the slit(21) changes to open configuration under the effect of pressure
developed inside the
cooker while cooking.
The secondary pressure indicator cum regulator means 13a (Fig 11) and 19a (Fig
10)
are designed to have elastically deformable type casing (15) with a central
non-metallic non-
deformable core(14) projecting from the bottom of the said casing(15).
The said core (14) in the secondary pressure indicator cum regulator 19a has a
slit (20)
at its distal tip. From closed configuration the slit(20) changes to open
configuration under the
effect of pressure developed inside the cooker while cooking.
The operating mechanism of the four types of secondary pressure indicator cum
regulator means at different levels of operating threshold pressures are as
follows:
The first type of secondary pressure indicator cum regulator means (13b) as
illustrated in
figure 12 has a deformable 'H' shaped tubular cylindrical structure that moves
upward under
increasing pressure to lift gradually the upper portion of the body.
Subsequently, the central flat
circular diaphragm(17) is pushed sealingly upwards and the bottom flange(18)
against the
underside of the cover. At first operating threshold pressure the upper
portion becomes visible
above the surface of the cover (2). At the second operating threshold pressure
the tubular
cylindrical structure gets ejected wholly from the cover (2) thereby acting as
a safety device.
Here the second operating threshold pressure is greater than the first
operating threshold
pressure.
The second type of secondary indicator cum pressure regulator means (19b) as
illustrated in figure 5 is different from the first type wherein the central
flat circular diaphragm
(17) has slit (21). This secondary indicator cum pressure regulator means
(19b) has a
deformable 'H' shaped tubular cylindrical structure that moves upward under
increasing
pressure to lift gradually the upper portion of the body. Subsequently, the
central flat circular
diaphragm (17) is pushed sealingly upwards and the bottom flange(18) against
the underside of
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CA 02707930 2010-06-22
the cover. At first operating threshold pressure the upper portion becomes
visible above the
surface of the cover (2). At intermediate operating threshold pressure the
slit (21) of the central
flat circular diaphragm (17) changes to open configuration thereby forming a
path for fluid from
interior to exterior of the cooker. At the second operating threshold pressure
the tubular
cylindrical structure gets ejected wholly from the cover (2) thereby acting as
a safety device.
Here the intermediate operating threshold pressure is greater than first
threshold pressure and
second operating threshold pressure is greater than intermediate operating
threshold pressure.
The third type of secondary pressure indicator cum regulator means(13a) as
illustrated in
figure 11 has a elastically deformable type casing(15) that deforms under
increasing pressure
to compress gradually towards the underside of the cover(2). Subsequently free
end of the core
(14) becomes visible above the surface of the cover(2) indicating the pressure
increase inside
the container. At first operating threshold pressure the free end of the core
(14) becomes visible
above the surface of the cover (2). At the second operating threshold pressure
the casing gets
ejected wholly from the cover (2) thereby acting as a safety device. Here the
second operating
threshold pressure is greater than the first operating threshold pressure.
The fourth type of secondary indicator cum pressure regulator means (1 9a) as
illustrated
in figure 10 is different from the third type wherein the core(14) has a
slit(20) at its distal tip.
This secondary indicator cum pressure regulator means (19a) has a elastically
deformable type
casing(15) that deforms under increasing pressure to compress gradually
towards the
underside of the cover(2). Subsequently free end of the core (14) becomes
visible above the
surface of the cover(2) indicating the pressure increase inside the container.
At first operating
threshold pressure the free end of the core (14) becomes visible above the
surface of the cover
(2). At intermediate operating threshold pressure the slit (20) of the
core(14) changes to open
configuration thereby forming a path for fluid from interior to exterior of
the cooker. At the
second operating threshold pressure the casing gets ejected wholly from the
cover (2) thereby
acting as a safety device. Here the intermediate operating threshold pressure
is greater than
first threshold pressure and second operating threshold pressure is greater
than intermediate
operating threshold pressure.
According to the invention, the said secondary pressure regulator means (19a,
19b) are
adapted to either reset or auto-reset the slit into close configuration
responsive to pressure
decrease below the intermediate operating threshold pressure. The said
secondary pressure
regulator means (13a, 13b, 19a, and 19b) are adapted to retract or auto-
retract into original
mounting position responsive to the pressure decrease within the closed cooker
enclosure from
the first threshold pressure to equal or below the ambient pressure.
According to the present invention, the gasket offset device (22) is also an
additional
secondary safety device. This safety Gasket Offset Device (GOD) is made out of
plastic and
silicone which pushes in the gasket(3) and does not allow pressure to build up
inside the
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CA 02707930 2010-06-22
container(1), if the cover(2) is not fitted or closed properly. This device is
called the gasket offset
device.
The said gasket offset means shall comprise of a flexible deformable lug
gasket mounted
along the wall of locking lug(4) of the cover(2). There is an opening with a
pathway provided in
the cover(2) between the interior of said cover(2) and interior of
opening/closing aid (4"). A free
sliding push rod is disposed in the said pathway of the said opening of the
cover(2) extending
partially into the interior of the cover(2) and into said interior of said
opening/closing aid (4") and
supportingly abutted against the said lug gasket, providing a fluid path
between the interior and
exterior of the cover(2) and enclosure. The free sliding push rod is adapted
to contact the cover
gasket (3) when the cover is moved for a sealing engagement with the container
(1). This
movement slidably and completely moves the push rod into the interior of the
locking lug (4)
and closes the fluid path with the cover gasket (3) between the interior and
exterior of the
enclosure, only when the cover gasket(3) is fully disposed on the cover rim.
Further the gasket
offset means has a detachable gasket offset device cover (30) fixable in
position with a screw
type fixing means (31).
The actual dimensions of various parts of the present invention described here
and
depicted in the figures are designed to have appropriate various values to
achieve the different
intended purpose of the concerned part.
Now the invention has been described to the best of our ability and knowledge
and any
modification, variation and deviation would come within the purview of this
invention.
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