Claims:1. A pressure cooker comprising

a. an open body with a continuous smooth peripheral extended sealing edge surface,
b. a cooker cover having a rim with peripheral sealing surface which is closeable against the cooker body about its open top; the said cooker cover having a first inner depending circular circumferential flange (A) for engaging seatingly on the top horizontal surface which extends about the body top edge and providing a first preliminary horizontal seal between the cooker cover and the body; a second outer set of overhanging circumferential partially extending plurality of flanges (B) extending to a level therebelow along vertical surface when the cooker cover is disposed over the body open top and providing a second preliminary vertical seal between the cooker cover and the body,
c. a locking/unlocking means having jaws (3) mounted on the said cooker cover, the said jaws moveable between a locking/engaged position in which the cooker cover is locked relative to the body by clamping together the peripheral edges of the body and of the cooker cover, and an unlocking/position, the said jaws are mounted to move substantially in radial translation relative to the cooker cover,
d. a drive means mounted on the cooker cover for moving the jaws between the locking/engaged position and the unlocking/retracted position of the jaws, and.
e. a cam means which interlocks the said jaws with the cooker cover, the said cam means having a groove/slot on the jaw and functionally associated with a pin having enlarged head extending from the cooker cover into the slot and adapted to be made operable when the jaw is relatively with respect to cooker cover pulled outwardly/inwardly during retraction/unlocked position or lock/engaged position, the slot is so locked that when the jaw is pulled outwardly/inwardly the enlarged head of the pin will abut tingly engage an end of the said slot and thereby limit further outward/inward movement of the jaw in that direction.
2. The pressure cooker as claimed in claim 1 is a microwave pressure cooker.
3. The pressure cooker as claimed in claim 2 is constructed of a microwave permeable material.
4. The pressure cooker as claimed in claim 1, wherein the said jaw is typically semi-circular with a U shaped profile at its outer end.
5. The pressure cooker as claimed in claim 1, wherein the said two jaws are positioned diametrically opposite each other on the cooker cover.
6. The pressure cooker as claimed in claim 1, wherein the drive means is arranged in the middle portion of the cooker cover and drives the jaws through a corresponding drive arm, which drive arm is integral with the corresponding jaw.
7. The pressure cooker as claimed in claim 1, wherein the drive means is a rotary type drive means, such that during rotation of drive means in one direction, the two jaws move inwardly and during rotation of device means in opposite direction the two jaws move outwardly.
8. The pressure cooker as claimed in claim 1, wherein the said jaws are interlocked in seal tight relation with the second overhanging flanges of the cooker cover to cause a secondary seal between the body and the cooker cover when the jaw is interlocked in locked position with the cooker cover.
9. The pressure cooker as claimed in claim 1, wherein the cooker cover may have gasket (8) typically arranged at the bottom side of the cooker cover and preferably the cooker cover has a rectangle gasket lug beneath to hold the gasket sealingly with the cooker cover.
10. The pressure cooker as claimed in claim 1, wherein the cooker cover may be closeable against the body along the open top in any position.
11. The pressure cooker as claimed in claim 1, may include a first diaphragm type pressure regulator means (7) disposed on the cooker cover with a moveable visual indicator operable cooperatively with a bellow (9) underneath which is responsive to pressure within the cooker, the said regulator means arranged within the said rotary drive means of the cooker.
12. The pressure cooker as claimed in claim 1, may also include a diaphragm type second and third pressure regulator means (8a,8b) with slits (11) disposed on the cooker cover, each operable at different operating thresholds disposed within a receptacle type regulator opening means (8a’,8b’) forming valve openings through the said cooker cover..
13. The pressure cooker as claimed in claim 1, may include a zero pressure device ZPD (12) arranged on the cooker cover with a secondary lock means (13) extending and operably interlocking with a slot arranged on the jaw, thereby preventing the jaw from opening in pressure condition of the cooker within and thereby also acting as a secondary locking device in combination.
14. The pressure cooker as claimed in claim 1, may include a pressure regulator housing means arranged on top side of the cooker cover proximate to ZPD and slit diaphragm type pressure regulator means having a wall for enclosing them therein.
15. The pressure cooker as claimed in claim 1 and 14, may include filter means (10) arranged on bottom side of the cover correspondingly below the housing means such that it is disposed below the zero pressure device ZPD, and the slit diaphragm type pressure regulator means, to prevent escape of cooking material outwardly out of the cooker.
16. The pressure cooker as claimed in claim 1, may include an additional top aesthetic cover mountable onto said cooker cover.
17. The pressure cooker as claimed in claim 1 and 16, wherein the top aesthetic cover will include an opening for access to rotary drive means arranged on the cooker cover.
18. The pressure cooker as claimed in claim 1, 16 and 17, wherein the top aesthetic cover will include a cutout covered with a removable vented mini lid (4), arranged correspondingly above the pressure regulator housing means of the cooker cover.
19. The pressure cooker as claimed in claim 1, wherein the rotating drive means is operable with a top knob (6).
20. The pressure cooker as claimed in claim 4, wherein the body/container (1) has a smooth inner surface and ribbed bottom.
21. The pressure cooker as claimed in claim 16, wherein the top aesthetic cover may have ribs and grooves on its bottom side for fitting onto the cooker cover.
22. The pressure cooker as claimed in claim 1, wherein the cooker cover may be a cover having a rim with peripheral non-sealing ribbed surface which is closeable against the cooker body about its open top for non-pressure cooking.
, Description: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

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.

U.S. Pat. No. 4,796,776 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.

U.S. Pat. No. 4,853,509 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.

U.S. Pat. No. 5,229,563 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.

U.S. Pat. No. 5,310,981 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 releasable locks the top cover. The top cover and inner cover of the pressure 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.

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.

In additional , Open and close in the existing Microwave cookers are much more difficult , As it has to be aligned to the body by the arrow mark and then closed, which requires effort to open and close, in order to reduce the efforts in open and closing the invention discloses a rotating knob at top, which can be rotated Anti clock wise and clockwise for open and close, this design will have no alignment and can be placed any direction and closed in Lid,

The invention provides a non sealing lid with the body as it never seals during cooking and it can be used for serving also,

The applicant is aware of many prior art some of which is listed below :

Cited Patent Applicant Title
US4490597 *
Mengel Clare L Microwave permeable pressure compensating container
US4796776
Northland Aluminium Products, Inc. Pressure cooker for microwave ovens
US4853509
Hario Kabushiki Kaisha Rice cooker for microwave ranges
US5229563
Matsushita Electric Industrial Co., Ltd. Pressure cooker
US5310981
Ensar Corporation Microwave cooker
US20020040906
Hakim Nouri E. Feeding dishes for children
WO2007122648A1
Giorgio Tosini Protecting membrane for a vessel adapted for cooking, freezing or storing foodstuff
WO2010049942A1
Ttk Prestige Limited Microwave pressure cooker

In general therefore there exists a need to improve the design of pressure cooker/microwave cooker, for better efficiency, easy usage and higher safety and that led to a search for solutions that enable easy and safe operation of pressure cooker/microwave cooker.

OBJECTS OF THE INVENTION

The main object is to provide a Microwave pressure cooking device which can overcome the various sufferings mentioned above and which ensures excellent overall safety in use.

Another object of the invention is to have a locking means demanding no alignment during closure/opening of the lid.

Another object of the invention is to propose a novel microwave cooking device which is particularly a simple design for open and close with a rotating knob at the top.

Another object of the invention is to propose a novel microwave pressure cooking device which prevents the removal of lid by an user when the pressure inside is high, by mere mechanical arrangement.

Another object of the invention is to propose a microwave pressure cooking device and which never seals when the non sealing lid is placed.

It is another object of the present invention is that the mechanical interlocking arrangement also serves another purpose that is a visual pressure indicator to the user, thereby making the system very reliable and relatively incapable of being fouled, excepting mischief attempt.

It is another object of the present invention there is a rotating knob which will rotate clockwise and anti clockwise for closing and opening , as the knob rotates there is left and right side clamps with moves in the open and close direction for locking.

DESCRIPTION OF INVENTION

In typical pressure cooker available in prior art, both the cover and body are provided with circumferentially spaced lugs at their periphery which are inter-engaged by relative rotation of the cooker body and its cover, the effect of which is to urge the upper edge of the cooker body against an appropriately located gasket so as to effect the required fluid tight seal there-between. So there is a need to place bottom edge of top cover on top edge of body carefully so that lugs of cover are interlocked with body lugs, since the lugs of the cover and of body are so arranged and related to each other for mutual engagement. Such engagement devices are rather inconvenient to manipulate and obviously add to the cost of manufacture also.

It is highly desirable that means provided for securing the cover in seating engagement with the cooker body be relatively simple, but which will allow securing the lid to the body without requiring the manipulation of several securing elements such as lugs, each time the cover is secured to the cooker body or removed therefrom.

In contrast to the foregoing disclosure of prior art, the present invention provides a simple and positive locking mechanism which provides reliable operation and safe operation under all conditions, including adverse operational condition, when the user is mindlessly operating the device.

According to the present invention, a microwave pressure cooker comprises of a container, a cover assembly, a cover gasket, pressure regulators and/or pressure indicators and all are constructed of a microwave permeable material.

Figure 1 illustrates the essential features of the design exterior of the cooker container. The crucial elements are polished surface in a designed pattern. The material of the container (1), Bottom lid (2), Jaws (3), Mini lid (4), Top lid (5), Knob (6), VPI (7) and all the plastic parts can be unfilled or filled polypropylene, Delrin, polycarbonate or any polymer compatible with microwave energy without deterioration of properties and which can give satisfactory mechanical performance at a continuous working temperature of 125° C with food.

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 container (1) portion of the cooker is such that there are smooth surface and variable thickness formed on it which not only strengthens but also facilitates easy of handling, The bottom of the container (1) has ribs which acts as a 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. The bottom of the container (1) is also strengthened and has ribs to ensure the container (1) is stable. The ribs also ensure that the bottom is always flat.

This unique pressure cooker as per the invention is a very attractive and strengthened to take care of the pressure. The Bottom lid (2) Assembles with the jaw on left and right and fixed with plastic screw. The unique top cover (5) is further strengthened with annular grooves and fixed to the bottom lid.

In one embodiment of the present invention, a microwave pressure cooker formed with a contained 1) open at its top shall comprises of some or all of the parts namely a cover assembly with a gasket adapted for ledge interlock type sealing and no lug locking engagement with the said container (1) to form an enclosure for pressure cooking with the container (1) However the jaws (3) also has handles integrated for lifting and closing the cover assembly. The bottom lid has (2) has ribs to strengthen and provide safety during use in normal and abnormal conditions, while minimizing the weight of the cooker. The bottom lid (2) has unique feature wherein the froth or Vapour is collected in a receptacle. The receptacle has a Mini lid (4). In the Bottom lid there is a receptacle type regulator opening forming valve openings through the said bottom lid (2). The said bottom lid (2) shall have at least two deformable diaphragm type pressure regulator means (8a, 8b) having different operating thresholds responsive to the pressure in the enclosure and with slits (11) formed therein is adapted to be disposed on the regulator opening means. A mini lid device means is mounted on top cover for releasable maintaining the said container (1) and the bottom lid (2) in said sealing engagement responsive to disposition of gasket on the bottom lid (2) and the movement of the said bottom lid (2) relative to the said container (1) to a lock position. A movable type jaw is assembled with the knob and fixed with the screw, the VPI is mounted with the bellow for indication that there is pressure or not. The mesh-like or perforated surface structure referred as filter means (10) is installed around and below the pressure release valves of the cooker. The filter has many holes which are slightly smaller than the size of air passage of pressure release valve of the cooker’s cover. During cooking the hot air or pressure inside the pressure cooker is allowed to escape when it is appropriate while the filter mesh prevents food particles that may close the air passage and pressure release valve from passing through the filter means, thus protecting the pressure release valves to function safely.

The opening is shown in figure 2 the jaws gets disengaged where the container can be separated from the cover assembly. The closing is shown in figure 3 the jaws gets engaged with the container lug which compress the gasket (8) and the sealed with cover assembly.

As per the invention, there are two different types of diaphragm type pressure regulator means (8a, 8b) is removable disposed.

The merits of the parts are illustrated in figures (1 to 14),

1. Container/body
2. Bottom lid/cooker cover
3. Jaws
4. Mini Lid
5. Top cover/aesthetic cover/top lid
6. Knob
7. Visual pressure Indicator VPI
8. Gasket
8a.& 8b - Primary and Secondary device
9. Bellow for VPI
10. Filter with Grommet
11. SLITS
12. ZPD
13. Secondary Locking Device
14. Cam means

Figure 1 illustrates the essential features of the design exterior of the cooker container.

Figure 2 illustrates the cross sectional view in open condition. The jaw will be disengaged with the bottom lid and body, allowing the lid assembly to be in open condition.

Figure 3 illustrates the cross sectional view of lid assembly in closed condition. The jaw will be engaged with the bottom lid and body, allowing the lid assembly to be in closed condition which will create the Pressure inside.

Figure 4 illustrates the top view of lid assembly showing safety locking devices. The figure shows the position of the safety locking device and safety operating devices.

Figure 5 illustrates the working of safety locking devices in lid assembly.

Figure 6 illustrates body design in cross sectional view, front and rear view.

Figure 7 illustrates bottom lid design in top & bottom view.

Figure 8 illustrates jaw design in front and rear view.

Figure 9 illustrates gasket design in cross sectional view.

Figure 10 illustrates knob design in front , rear & side view.

Figure 11 illustrates Vpi design in cross sectional view, front and rear view.

Figure 12 illustrates locking nut designs.

Figure 13 illustrates the bottom lid in different view to simulate jaw stopper portion (B) and jaw entering portion (A). The portion A is semi circle area and it guides the jaw to move frontward and backward. The portion B is having extra projection will act as a stopper for jaw from moving forward.

Figure 14 illustrates the bottom lid and jaw in closed and retracted position, the portion B will act as a stopper for jaw to move forward.

The elastomeric pressure regulator. The material of the pressure regulator can be silicon rubber, fluoro elastomeric, or any other elastomeric which can stand a continuous working temperature of 1250C and which is compatible with microwave energy without deterioration of properties. All the regulators 8a, 8b and visual pressure indicator cum regulators are unique in the sense that they can be disposed on the cover in either direction.

A pressure regulator valve with a slit (11), made of Silicone rubber will maintain a selected operating pressure level in the pressure cooker. It is a device where in the safety feature does not use a dead weight or a spring like conventional pressure cooker. The Pressure regulation is done by a Silicone device. Thus it is different as it does not have the dead weight design that is normally used in all types of conventional cookers. There will be at least two of these regulators which act at different pressure levels. When the pressure in the cooker body rises to a certain level, the high pressure will prop up the diaphragm upwardly.

It also has another unique feature of guiding channel which used to guide the regulated vapour or froth from cooking food into the receptacle formed in the centre of the Bottom lid (2) and not sprayed out in the bottom (2) surface like a normal conventional regulating valve. As per the invention, an elastically deformable pressure regulator diaphragm is formed of microwave permeable flexible material with a slit (11) made thereon, such that when it encounters a pressure increase inside the closed cooker is deformed into a open configuration responsive to pressure development within the closed cooker.

The pressure regulator comprising a diaphragm(9) fixed to the bottom lid (2) of a pressure cooker on a regulator means forming a regulator opening through the said bottom lid (2).
A pressure regulator having a operating threshold, the regulator being of the type comprising an elastically deformable diaphragm body fixed to the bottom lid (2) of a pressure cooker and having a slit (11) in closed configuration formed therein, the regulator is such that the diaphragm is deformed to change the slit (11) into an open configuration under the effect of the pressure applied on the diaphragm.

In accordance with the present invention, a microwave pressure cooker formed with a container (1) open at its top shall comprise of a Bottom lid (2) with a gasket(8) adapted for sealing engagement with the said container (1) to form an enclosure for pressure cooking within the container (1) and a pressure regulator means(8a, 8b) which has a pressure responsive diaphragm adapted to be disposed on the Bottom lid (2) of the cooker and further it is characterized in the non-metallic deformable microwave permeable diaphragm type pressure regulator means(8a,8b), with or without a top cover. The diaphragm (9) responds when encountering a pressure increase and the diaphragm compresses and the VPI will be raised. The said diaphragm (9) is further characterized with a flat disc shaped pressure responsive member.

According to the present invention, another Vpi regulator safety device made out of Silicone rubber and plastics performs function, it works as a visual pressure indicator, indicating the pressure inside cooker. This would indicate when the Cooker is having pressure inside. The indication is by pop up of the central portion of the device.

Secondly, there is a secondary safety device which releases the pressure, in case the Pressure regulator fails to operate for various reasons and also when there is an excess pressure ie. more than the operating pressure, well below the design & Test pressure. Normally this pressure is around 0.5 Kgs/sqcm.

Thus it is definitely a unique dual usage device.

As per the Present Invention, there is a mini lid fitted to the top cover, which will swell, when we want to make the QRS the mini lid can be pressed and the secondary device will release the excess steam outside.

As per the invention, this elastomeric secondary safety device designed with a diaphragm having a slit will rises up above the surface of the lid to indicate the presence of such internal pressure, whenever the pressure inside the cooker exceeds ambient pressure. Likewise during cooling after cooking the device remains in the raised position till the internal pressure falls to Non - Hazardous levels.

As per the invention, this elastomeric secondary safety device designed with a diaphragm having a slit will open to release excess pressure above the designed opening pressure of this device during cooking operation, if the primary pressure regulator malfunctions and the internal pressure increases beyond the normal maximum operation pressure. As per the invention, this elastomeric secondary safety device designed with a diaphragm having a slit will be ejected completely out of the mounting hole releasing all internal pressure in the cooker to ambient pressure during the cooking operation, if there is a malfunctioning and the internal pressure continues to increase beyond the maximum designed operating pressure of this device.

According to the present invention, secondary safety device designed with a diaphragm having slit, which has four different functions which described as follows:

1. Whenever the pressure inside the cooker exceeds ambient pressure, the device rises up above the surface of the lid to indicate the presence of such internal pressure. Likewise during cooling after cooking the device remains in the raised position till the internal pressure falls to Non - Hazardous levels.

2. During cooking operation, if the primary pressure regulator malfunctions and the internal pressure increases beyond the normal maximum operation pressure, the
- slit in the diaphragm of the secondary device opens to release excess pressure above the designed opening pressure of this device.

3. During cooking operation as said in step 2 above, if there is a malfunction and the internal pressure continues to increase beyond the maximum designed operating pressure of this device, the whole device is ejected completely out of the mounting hole releasing all internal pressure in the cooker to ambient pressure.

4. The device is designed symmetrically so that it can be mounted in any way on
An Visual pressure indicator consisting of a non-metallic non deformable core projecting from bellow which is fitted to the bottom lid and as shown in figure 4 & 5, there are two locking devices which operates when the pressure is there in the container. Firstly there is a Zero Pressure Device ZPD (12) which locks the jaw to prevent the opening in pressure condition, there is a washer for ZPD to provide sealing, secondly there is a secondary locking device (13) which locks the other jaw to prevent it from opening in pressure condition the secondary locking device is fitted to the bellow and the bellow is fitted to the bottom lid.

Figure 5 shows the H- shaped design of elastomeric visual pressure indicator cum pressure regulator device wherein this device will be blown out from the hole provided in the lid on to which the device has been disposed and this function will happen when the pressure inside the cooker reaches to 0.7Kg/sq.cm and when the pressure regulator valve fails to open out the pressure when it pressure reaches to its threshold pressure.

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.

The invention provides many technical solutions.

In one aspect, the invention is for a microwave pressure cooker formed with a container (1) open at its top comprising some or all of the following:

(a) a cover assembly with a gasket adapted for ledge interlock type sealing and lug locking engagement with the said container (1) to form an enclosure for pressure cooking with the container (1);
(b) a receptacle type regulator opening means (8a,8b) forming valve openings through the said cover assembly ;
(c) at least two deformable diaphragm type pressure regulator means (8a,8b) with slits (11) formed therein adapted to be disposed on the regulator opening means, responsive to the pressure in the enclosure and having different operating thresholds;
(d) a ZPD which locks the jaw to prevent it from opening under pressure condition and a secondary locking devices which locks the jaw to prevent it from opening under pressure
(e) a movable type pressure indicator means adapted to be disposed in the opening formed on the cover assembly so as to rise visibly outward responsive to pressure in the enclosure.

In another aspect, the invention is for a microwave pressure cooker formed with a container (1) open at its top comprising some or all of the following:

(a) A bottom lid with a inside rectangle size gasket lug which allows the gasket to get aligned and locked with the bottom lid for sealing.
(b) a receptacle type regulator opening means(8a, 8b) forming valve openings through the said bottom lid (2);
(c) at least two deformable diaphragm type pressure regulator means (8a, 8b) with slits (11) formed therein adapted to be disposed on the regulator opening means, responsive to the pressure in the enclosure and having different operating thresholds;
(d) a movable type pressure indicator is place in the knob for indicating the pressure inside the container

In another aspect, the invention is for a microwave pressure cooker having clamps/jaws (3) on both sides is used for locking the container (1) with the cover assembly, the clamps has lugs with c shape channel that moves with sliding mechanism as it is linked with the knob, this as the knob rotates clockwise and anti clockwise the Clamps gets engaged and disengaged

In another aspect, the invention is for a microwave pressure cooker as described above, wherein the receptacle type regulator opening means (5a, 5a') is a hole formed on the bottom lid (2) on to which the diaphragm type regulator means (8a, 8b respectively) is removable disposed.

In another aspect, the invention is for a microwave pressure cooker as described above, wherein both the diaphragm type pressure regulator means(8a, 8b) is mounted in a corresponding receptacle of a hole type(5a, 5a' respectively hole on the bottom lid ).
In another aspect of the invention is for a microwave pressure cooker claims that has two safety locking devices ensuring that the cooker will not be opened when the pressure is inside the container , the locking devices will lock the jaw slot when the pressure is raised and it automatically release both the locking devices without any external force for unlocking.

In another aspect, the invention is for a microwave pressure cooker as described above such that the ZPD is a primary locking device where it lock the jaw when the pressure is raised in the container and release automatically when the pressure is zero .

In another aspect, the invention is for a microwave pressure cooker as described above such that the secondary locking devices where it lock the jaw when the pressure is raised in the container and release automatically when the pressure is zero.

In another aspect, the invention is for a microwave pressure cooker as described above such that the knob (6) is rotates clockwise and anti clockwise for engaging and disengaging with the container.

In another aspect, the invention is for a microwave pressure cooker as described above such that the container is provided without the lugs cut along the outer surface for facilitating grip and to lock in any position.

In another aspect, the invention is for a microwave pressure cooker as described above such that the cover gasket is generally V shaped in cross section.

In another aspect, the invention is for a microwave pressure cooker as described above such that the pressure cooker as a whole is non-metallic and of microwave permeable material.

In another aspect, the invention is for the pressure regulator means (8a,8b) of a microwave pressure cooker as described above such that all the regulators are elastomeric.

In another aspect, the invention is for the pressure regulator means (8a,8b) of a microwave pressure cooker as described above such that some of the regulators are elastomeric.

In another aspect, the invention is for the receptacle type regulator opening means (5b) of a microwave pressure cooker as described above is elastomeric.

In another aspect, the invention is for a microwave pressure cooker which includes a Visual pressure indicator on the centre of the knob which raises up when the pressure is increased and there is bellow fixed to the VPI and bottom lid, due to the elastomeric of the bellow when the pressure drops to zero the bellow will lower the VPI to original position.

This invention provides a novel technical solution to the omnipresent risk associated with explosion caused by top much pressure inside the cooker or suffering due to non-developing of pressure inside due to non-sealing between cover and body during cooking. The risk and the suffering of the prior is alleviated simultaneously in this invention which combinedly exhibit the uniqueness of the product and extraordinary advantage of the product. The invention teaches a new design of the cover/lid of the cooker, a new arrangement of pressure release valves etc and providing a significantly novel and safer pressure cooker/microwave pressure cooker.

The inventive arrangement of cover and body is thus characterized in that it can be used universally and not restricted to pressure cooker used with gas stove or microwave pressure cooker. The use is not restricted to a certain pressure cooker body size. The additional advantage is that desired pressure conditions can be achieved and controlled also, without any special means provided at the body of the cooker. The locking means provided on the cooker cover are sufficient to produce a form-locking type connection and force-locking type connection between the cooker cover and cooker body. Briefly stated, the invention also provides an interlock that prevents the user from disengaging the cooker cover from the cooker body, and operation is prevented if the pressure inside the cooker body is not below the predetermined valve allowing disengagement.

The embodiments disclosed herein are only few preferred embodiments of this invention and it should be noted that certain modifications and improvements can be made by those of ordinary skill in the art without departing from the spirit of this invention, which also fall within the scope of protection of this invention.