FORM -2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
PROVISIONAL/COMPLETE SPECIFICATION
(See Section 10 and rule 13)
Title of the Invention "AN IMRPOVED PRESSURE REGULATING SYSTEM FOR RELEASE OF EXCESSIVE PRESSURE WITHIN A PRESSURE COOKER"
1. Applicant(s): HAWKINS COOKERS LIMITED
Name, Nationality An Indian Company of
Address: Maker Tower F 101, Cuffe Parade, P.O.Box 16083,
Mumbai- 400 005, India
2. Preamble to the description:
PROVISIONAL : The following specification describes the invention.
COMPLETE : The following specification particularly describes the invention and the manner in which it is to be performed.

CROSS REFERENCE
The present invention is a Patent of addition of the Indian Patent No 203867.
FIELD OF INVENTION
This invention relates to an improved pressure regulating system for release of excessive pressure within a pressure cooker. In particular, though not limited thereto, this invention relates to an improved design of pressure regulating system for release of excessive pressure within a pressure cooker that has lowered the rejection rate less than 1% and testing less then 5%.
BACKGROUND OF INVENTION
It is generally known to provide a pressure regulating system with the lid of a pressure cooker so as to release the pressure within the vessel of a pressure cooker. The pressure regulating system comprises a valve or vent tube secured to the lid, the vent tube communicating with the inside of the vessel of the pressure cooker.
A valve or vent body is placed over the vent tube and to engage said tube. The vent body has a depending vent plug and a vent weight, said vent plug adapted to open or close the mouth of the vent tube, depending upon the pressure within the vessel. In the condition of an excessive pressure, the vent plug is lifted in the upward direction so as to open the mouth of the vent tube and allow a discharge of steam from within the vessel and thereby causing a desired drop in the pressure.

Several distinct disadvantages are associated with such a known construction of a pressure regulating system, and which have been recognized by the present invention. One such disadvantage is the lift of the vent weight. As the vent weight of the known art had a substantial lift, the release in pressure within the vessel was extended over a substantial period resulting in a substantial pressure drop. Yet another disadvantage was the substantial sound of the whistle produced upon lifting of the vent weight. A further disadvantage was the discharge of frothy foods during the lifted position of the vent weight.
This pressure regulating system is very much non-forgiving in nature, i.e. a small variation in dimension sometimes leads to improper whistling behavior of the system during steam testing. Due to this our rejection rate was high and we have to do 100% steam testing before sending it to the market. To solve this problem, the present invention provides a further modified design which is much more forgiving than the patented one, has been made. With this design the rejection rate has come down drastically to the range of less than 1% and the testing is reduced to 5% only. This has served the purpose of reduction in cost of manpower and testing facility involved in testing.
OBJECTS OF THE INVENTION
It is therefore, an object of this invention is to propose a pressure regulating system for use with a pressure cooker and which obviates the disadvantages of the known art.
Another object of this invention is to propose a pressure regulating system for use with a pressure cooker, which maintains a better

pressure within the pressure cooker in comparison to that of the known art.
Another object of this invention is to propose a pressure regulating system for use with a pressure cooker, which facilitates an easier insertion removal of the vent weight from the vent tube.
Another object of this invention is to propose a pressure regulating system that has reduced the rejection rate to the range of less than 1 % and testing to 5%.
Yet another object of this invention is to propose a pressure regulating system for use with a pressure cooker which minimizes sprouting of food through the vent tube.
Further objects and advantages of this invention will be more apparent from the ensuing description.
At the outset of the description, which follows, it is to be understood that the ensuing description only illustrates a particular form of this invention. However, such a particular form is only an exemplary embodiment, and without intending to imply any limitation on the scope of this invention. Accordingly, the description is to be understood as an exemplary embodiment and teaching of the invention and not intended to be taken restrictively.
SUMMARY OF THE INVENTION;
According to this invention, there is provided an improved pressure regulating system for release of excessive pressure within a pressure cooker comprising a vent tube extending downwardly from the lid, a vent

body or weight having a conical vent seal to open or close the mouth of the vent tube characterized in that said vent weight has a lift of 0.5 to 2.5 mm, and preferably 1.0 to 2.0 mm, wherein 4 Steam Exit Holes have been lowered by 1.1 mm and correspondingly the height of Cowl in increased by 1.1 mm to maintain the same relation between Cowl and Holes.
BRIEF DESCRIPTION OF THE DRAWINGS;
Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawings and wherein:
Fig. I shows the pressure regulating system of the known art with the vent weight in a seated position;
Fig.2 shows the same system of fig. 1 but with the vent weight in a lifted position;
Fig.3 shows the improved pressure regulating system of the present invention with vent weight in a seated position; and
Fig. 4 shows the system of fig.3 with the vent weight in a lifted position.
Fig. 5 shows the pressure regulating system of the main application and the present invention.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS;
To overcome the said disadvantages of the Patent no 203867, the present invention provides a new design, where 4 Steam Exit Holes have been lowered by 1 to 1.2 mm and correspondingly the height of Cowl is

increased by 1 to 1.2 mm to maintain the same relation between Cowl and Holes.
In accordance with the main invention, the pressure regulating system includes a vent weight as also provided in the known art. However, the lift of the vent weight of the present invention is less in comparison to that of the prior art, In the known systems, the lift of the vent weight was between 2.5 to 4.5 mm and preferably between 2.5 to 4.00 mm. In distinction, the vent weight of the present invention has a lift of 0.5 to 2.5 mm preferably 1 to 2 mm. Such a reduction in the lift of the vent weight is provided by increasing the bottom taper angle 15 to 25 degrees, and preferably in 19 to 21 degrees with respect to the vertical axis of the vent tube in comparison to that of the prior art of 12 to 18 degrees, and preferably 14 to 16 degrees. Further, the top taper angle of the vent tube of the present invention is reduced to 15 to 25 degrees, and preferably 19 to 21 degrees with respect to the vertical axis in comparison to that of the prior art of 25 to 35 degrees, and preferably 29 to 31 degrees. As a result of the lower lift, the vent weight drops back faster on the vent tube. In a pressure cooker, the pressure keeps dropping as long as the vent weight remains in a lifted condition since steam is released into the atmosphere during such a period. However, with the vent weight of the present invention, the pressure drop is less as the lifted condition is for a shorter period.
Further, in accordance with the main invention, the annular gap between the bore of the vent tube and conical vent seal or plug is less in comparison to that of the prior art. Thus, there is a reduced area for foods to sprout, such a reduction in area with a reduction in the lifted condition of the vent weight is responsible for a reduction in the sprouting of food.

In addition, the vent tube bottom taper has a blending radius 1 to 5 mm, and preferably 2 to 4 mm. Similarly, the blending radius of the vent tube top taper is 1 to 5 mm, and preferably 2 to 4 mm. As a result, the force to insert and remove the new vent weight with respect to the vent tube is considerably less in the new system, making the new system more consumer-friendly. The annular gap between the cowl and the vent weight body is less in the vent weight of the present invention and between 1.5 to 2.5 mm, and preferably 1.8 to 2.2 mm in comparison to 2.5 to 3.5 mm, and preferably 2.8 to 3.2 mm of the prior art. This combined with the fact that the vent weight remains lifted for a shorter period while whistling, allows the sound of the whistle to be softer in comparison to that of the prior art. The vent weight body is usually turned to the required shape from a solid rod in an automat machine. Since the vent weight body of the present invention is cylindrical in shape unlike the existing one, which is conical in shape, the scrap losses while turning is less in the present invention. Hence to get identical finished weight, the height of the new vent weight in the present invention is substantially smaller than the existing vent weight body.
However, this pressure regulating system is very much non-forgiving in nature, i.e. a small variation in dimension sometimes leads to improper whistling behavior of the system during steam testing. Due to this our rejection rate was high and we have to do 100% steam testing before sending it to the market. To solve this problem, the present invention provides a further modified design which is much more forgiving than the patented one, has been made. With this design the rejection rate has come down drastically to the range of less than 1% and the testing is reduced to 5% only. This has served the purpose of reduction in cost of manpower and testing facility involved in testing.

Referring to figs. 1 and 2, the pressure regulating system of the known art and provided in a pressure cooker comprises a vent tube 1 secured to a lid of a pressure cooker (not shown) and extending within the vessel of said pressure cooker. Vent tube 1 supports a vent weight 2 through a seated position (fig. 1) to a lifted position (fig.2) to allow a release of pressure from within the vessel. As shown in fig.2, the lift of vent weight was substantial and between 2.5 to 4.0 mm.
Vent tube 1 has a top taper 2a with an angle of 12° to 18° and bottom taper 2b with an angle of 25° to35°.
Vent body or weight 3 has a conical vent seal 4 adapted to open or close the mouth of vent tube 1. Conical vent seal 4 is fitted to vent weight 2. A cowl 5 with a hook 6 are also fitted to vent weight 2. As shown in fig.l, the wall surface of vent tube 1 between top taper 2 a and bottom taper 2b is sharp.
Reference is made to figs. 3 and 4 which shows a pressure regulating system of the present invention also comprising a vent tube 10 having a top taper surface 10a and a bottom taper surface 10b. However, in accordance with the present invention, top taper surface 10a has an angle of 15 to 25°, and preferably 19 to 21° with respect to the vertical. Similarly, lower taper surface 10b has an angle of 15 to 25°, and preferably 19 to 21° with respect to the vertical.
Further, and as shown in figs. 3 and 4, the lift of the vent weight 12 is only 0.5 to 2.5 mm, and preferably 1.0 to 2.0 mm.

Still further, the annular gap between cowl 15 and vent weight 12 is 1.5 to 2.5 mm and preferably 1.8 to 2.2. mm in comparison to 2.5 to 3.5 of the known art. As apparent from figs. 3 and 4, the system further comprises a conical vent seal 14 and hook 16.
Fig. 5 shows a new design, where 4 Steam Exit Holes have been lowered by 1 to 1.2 mm and correspondingly the height of Cowl in increased by 1 to 1.2 mm to maintain the same relation between Cowl and Holes.

WE CLAIM;
1. An improved pressure regulating system for release of excessive pressure within a pressure cooker comprising a vent tube extending downwardly from the lid, a vent body or weight having a conical vent seal to open or close the mouth of the vent tube characterized in that said vent weight has a lift of 0.5 to 2.5 mm, and preferably 1.0 to 2.0 mm, wherein 4 Steam Exit Holes have been lowered by 1 to 1.2 mm and correspondingly the height of Cowl in increased by 1 to 1.2 mm to maintain the same relation between Cowl and Holes.