|Title of Invention||
A FUEL EFFICIENT PRESSURE COOKER
|Abstract||The present invention relates to an improved pressure cooker, particularly a pressure cooker which is sleek and more efficient than the existing pressure cookers available in the market. A pressure cooker is an airtight utensil for quick cooking or preserving of foods by means of super heated steam under pressure.|
|Full Text||FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
THE PATENTS RULES, 2003
(Section 10; rule 13)
TITLE OF THE INVENTION An improved Pressure Cooker
Tasgaonkar Ghanashyam Shankar and Tasgaonkar Prabha Ghanashyam, both are Indian nationals, of D- 9 Vatsalyapuram, Kumbare Township, Off Eklaya College Road, Kothrud, Pune 411 029, Maharashtra, India
The following specification describes the invention. -1-
An improved Pressure Cooker
The present invention relates to an improved pressure cooker, particularly a pressure cooker which is sleek and more efficient than the existing pressure cookers available in the market. A pressure cooker is an airtight utensil for quick cooking or preserving of foods by means of super heated steam under pressure.
The present day pressure cookers are designed just like any other cooking utensils as far as external heat transfer and the transfer of heat to the products to be coked are concerned. In none of the available pressure cookers, any special consideration has been given by the manufacturers regarding the improved mode of heat transfer, which plays a major role in the operating efficiency of a pressure cooker.
The heat transfer in a pressure cooker is by boiling water, thereby generating steam and transferring of heat due to condensation of steam on the external sides of the containers or utensils used in a pressure cooker known as separators.
The known pressure cookers consist of a main metallic body or body made of aluminum or alloy. The main body is generally provided with an extra thick base with an integrated lid, which can ensure pressure tight arrangement by means of a resilient gasket, which is usually made of rubber. The lid is provided with a safety valve. This valve permits to increase pressure within the cooker for easy and fast cooking of food with high fibre and low fat in record time. Further, the pressure cooker is gaining popularity because it helps to preserve vitamins and essential nutrients.
The valve in the pressure cookers permits to have increased pressure in the cooker for easy and fast cooking. The valve blows steam when the pressure within the cooker increases beyond the predetermined and desired value. Differently designed
containers are provided to keep food to be cooked in the pressure cooker. A perforated plate is adapted to be kept at the inside bottom of the pressure cooker. Required quantity of water is poured into the cooker, the food to be cooked is placed in the separators or containers as provided and the pressure cooker is ready for use.
The high temperature flame gives heat to the bottom surface of the pressure cooker. The water at the bottom gets heated first. When water reaches its boiling temperature, the generation of steam starts. Steam then heats the utensils by condensing on the outer surface thereof.
The integrated lid at the top helps in increasing the pressure inside the cooker. Nevertheless, the lid loses heat by convection and radiation to the atmosphere.
The following are the disadvantages of the presently available pressure cookers-
a) Major amount of heat gets transferred and thus gets lost from the bottom surface of the pressure cooker. But no special arrangement has been proposed or provided to increase the heat transfer area and to reduce the wastage of heat. Further, lot of heat is lost because of radiation and air currents.
b) Theoretically, the boiling heat transfer coefficients are very high. However, no special arrangement has ever been successfully made to enhance the boiling performance of the bottom surface.
c) The lower most special utensil placed inside the pressure cooker is partly dipped in water, the effect of this is that the process of boiling of water or generation of steam does not begin until the contents of the lower utensil are sufficiently heated.
Hence, during this period the mode of heat transfer from the bottom surface to water is possible by convection. The heat transfer coefficients by convection are very much lower than that by nucleate boiling.
The cooking of food in pressure cooker continues even after the cooker is removed from the fire. During this period, the heat transfer is generally required to be reduced as much as possible. However, in the known art there is no arrangement to control the heat transfer. It is possible to reduce the time of cooking and fuel if the process of cooling of the pressure cooker can be effectively controlled.
One of the objects of the present invention is to propose an improved pressure cooker, which is free from the defects of the known types of the cookers.
Another object of the present invention is to provide a thermally efficient cooker.
A further object of the present invention is to have a pressure cooker, which will consume less fuel.
A still further object of the present invention is to provide a pressure cooker, which reduces the total cooking time.
A still another object of the present invention is to provide an improved pressure cooker can cook healthy and fast food and at the same time preserving the vitamins and essential nutrients in record time.
The improved pressure cooker of the present invention has the following main characteristics:
i) Increased heat transfer area at the bottom surface of the cooker thus reduces the effect of passing wind and the loss of heat from the flame by radiation.
ii) Provides a rough surface for trapping air in micro-cavities for enhanced nucleate boiling.
iii) Low cost stand for support of utensils.
iv) A removable insulation cover on the lid and the main cooker body for controlling the losses.
The present invention is described herein below in detail with reference to the accompanying drawings, wherein-
Fig. 1 illustrates a known pressure cooker.
Fig. 2 illustrates the new and improved pressure cooker of the present invention.
Fig. 3 shows mainly the bottom surface of the known pressure cooker.
Fig. 4 shows the bottom surface of the improved pressure cooker of the present
Fig. 5 illustrates the insulation of the integrated lid of the improved pressure cooker.
With reference to Fig. 1 a known pressure cooker essentially comprises a main body (01) made of aluminum or other metal or an alloy having a relatively thick circular base (11) and less thick sidewall. The open top of the main body is covered with a
lid (12) having a peripheral groove in which sits a rubber gasket (13) to make the
DO pressure cooker airtight with the help of a locking member, located in the handle
bar(18). The lid is provided with a vent tube (20) at its centre to adapt a safety valve
(22). Before cooking, require amount of water level (30) is maintained in the main
body and a perforated circular disc/ plate (35) is placed within the main body to
support one or more utensil, container or separator (40) which holds the food to be
The improved pressure cooker of the present invention as shown in Fig. 2 comprises a main metallic body (100).A metallic ring (110) is attached / welded to
the outer bottom surface of the pressure cooker main body. The said metallic ring is either a continuously body or adapted in multiple sectors, preferably formed in four sectors to accommodate the supports on LPG stove or similar fuel burner stand. In a preferred embodiment of the invention, the ring is provide with multiple holes (120) is welded/ attached at the edge. It is a complete ring, the height of which is so selected that that ring does not touch the ground.
In another embodiment of the invention, the height of the ring is so selected hat the utensils rest on the ground through the ring.
Further, the burner is enclosed within the inner periphery of the ring. This prevents the effect the effect of breeze or air current deviating the flame and hence the heat. Moreover, as the burner is enclosed in a ring the loss of heat by radiation from the flame is minimal or reduced largely. This avoids the hardship of the housewives or the persons standing close the stove. The said ring is provided with plurality of holes so that hot gases of combustion flow through these holes and the waste heat is recovered by the ring. This improves considerably the thermal efficiency of the pressure cooker.
In a further embodiment of the invention, a rough surface (130) is provided at the bottom portion of the pressure cooker. The said rough surface is created either by machining, grooving, sand blasting, sintering metallic coating or any other processes. These cavities increase the bubble formation. The said rough surface has innumerable tiny cavities, which can trap air within them. These cavities along with surrounding air form a nucleus for bubble's birth. As the bubbles are formed at the nuclei, the nucleate boiling is generated. A great turbulence is created during bubble formation and collapse. This turbulence offers a very high rate of heat transfer as shown in Fig.3.
In a preferred embodiment of the pressure of the present invention, a stand (150) made up from small round bar of sufficient height is positioned under the lower
most bottom utensil in the cooker so that said utensil does not touch the water in the cooker. Thus, the complete heat transfer is possible due to boiling heat transfer.
In still another embodiment of the present invention, two insulation covers in the form of insulating ring (160) and (161) are provided, one for the lid and the other for the main body of the cooker. The air trapped within the space of the cover and the main body of the pressure cooker acts as insulation. These insulation covers reduces the loss of heat and improves the efficiency of the cooker.
Dated this 8th day of August
|Indian Patent Application Number||1284/MUM/2006|
|PG Journal Number||49/2011|
|Date of Filing||14-Aug-2006|
|Name of Patentee||TASGAONKAR GHANASHYAM SHANKAR|
|Applicant Address||D-9 Vatsalyapuram,Kumbare Township,Off.Ekalya College Road,Kothrud,Pune-411 029,|
|PCT International Classification Number||A47J|
|PCT International Application Number||N/A|
|PCT International Filing date|