GB2217975A

GB2217975A - Steam cooker

Info

Publication number: GB2217975A
Application number: GB8810575A
Authority: GB
Inventors: Kun-Ming Chen
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-05-05
Filing date: 1988-05-05
Publication date: 1989-11-08
Anticipated expiration: 2008-05-05
Also published as: GB8810575D0; GB2217975B

Abstract

A uniform heating responsive steam cooker has one outer (1) and one inner pot (9). The inner pot contacts neither a heat source nor the outer pot. The outer pot has a depression (2) for containing water. A ring case (12) sealingly connects the inner and outer pots, and separate covers (8, 20) cover the outer and inner pots. A tube (25) pierces the outer pot (1) and connects the space between the inner and outer pots to a valve chamber (24, 30). The valve chamber contains a cooling water automatic recycle valve (34), a safety valve (35), a breathing valve (36) and an adjustable pressure valve (37). The safety valve (35) has a weight (352) which is pushed upwards when the steam pressure is too high. The breathing valve has a soft plug (365) and a movable rod (364) fitted in its centre. The construction of this adjustable pressure valve (37) is more clearly seen in Figure 2 (not shown here). <IMAGE>

Description

TITLE: A uniform heating responsive steam cooker This invention relates to a uniform heating responsive steam cooker.

In modern living, various kinds of cookers are used, e.g. electric cooker, automatic rice cooker, steu cooker and so on, Majority of then are direct heating type; in words, inner pot is placed on the outer pot and directly touches and is heated by heat source. In this way, food at the bottom will be firstly and vigorously heated, and its temperature raises rapidly, whereas food at the upper part is heated slouly and indirectly. Because of the non-uniform heating, food at bottom touching heat source is violently heated and consequently nutrients are almost destroyed within short time, and is charred or too tough, while food at upper part is not boiled enough, and deliciousness is greatly reduced.Furthermore, much time is needed in case food are needed to be simmered according to traditional cooking method; though it can retains its deliciousness, it is not proper for current busy men.

Because of the merits mentioned above, this utility is designed so as to persist food deliciousness and nutrients , and save time. This invention is composed of an outer pot which has a shallow depression at the bottom with a drain valve, an inner pot with several protuberances, a ring plate installed on the outer pot for anchorage of inner pot, an exhalation valve, several pressure valves, a breathing valve, an adjustable pressure valve, and a cooling water recycle valve.

In one embodiment of this invention, inner and outer pot are tightly linked, forming a close heating space in between, pressure of space can be properly adjusted by means of pressure valve, breathing valve, adjustable pressure valve and safety valve.

In another embodiment of this invention, part of the steam will be exhaled through the exhalation valve on the upper cover if pressure inside exceeds the pressure limit of this valve. In particular, steam in inner and that in outer pot are completely separated, independent and not interfered.

Also, in this invention, inner pot is hung above the outer pot without direct contact with heater. It is characterized by its uniform heating of the entire inner pot by the steam in outer pot.

Moreover, this invention possesses a valve chamber consisted of an adjustable pressure valve, a safety valve, a breathing valve, and also a cooling water automatic recycle valve which can recycle the water condensed on the ambient chamber wall back to the outer pot and thus will not affect the normal functioning of valves because of accunulation of condensed steam.

In one embodiment, this invention possesses an adjustable pressure valve, a safety valve and a pressure valve, all of which can operate individually and independently to discharge steam according to pressure size.

The maximum pressure tolerated by adjustable pressure valve is less than or equal to that of pressure valve, and that of pressure valve is less than than of safety valve. After from their proper adjustment of pressure, they ensure safety in operation.

This invention has a shallow depression at the bottom with a drain valve constructed for drainage.

In a further embodiment of this invention, the safety valve, breathing valve and cooling water recycle automatic valve in valve chamber are necessary accessories, whereas pressure valve and adjustable pressure valve are optional embodiments.

In another embodiment, the cooperation of safety valve, breathing valve, cooling water automatic recycle valve, and pressure valve installed on ring case permits the availability of uniform heating by steam and thereby responsive cooking.

Adjustable pressure valve cooperates with safety valve, breathing valve and cooling water automatic recycle valve, with no pressure valve installed, availing the cooker of uniform heating by steam and responsive cooking.

In an embodiment, the possession of safety valve, breathing valve, pressure valve, cooling water automatic recycle valve and adjustable pressure can enhance the invention functions and safety.

An embodiment of this invention is described by ways of example with reference to the drawings as follows in which: Fig. 1 The longitudinal sectional view of an embodiment of this invention.

Fig. 2 The schematic perspective view of this invention.

Fig. 3 The longitudinal sectional view of cooling water automatic recycle valve of this invention.

Fig. 4 Longitudinal sectional view of valve chamber of this invention.

Fig. 5 Longitudinal sectional view of pressure valve in ring case when in closure.

Fig. 6 Longitudinal sectional view of pressure valve when pushed up by vapor.

Fig. 7 Stereoscopic view of drain valve and drain of this invention.

Fig. 8 Schematic view of assembly of outer pot, inner pot and ring case of this invention.

Fig. 9 Top view of ring case of this invention.

Fig. 1 is the longitudinal sectional view of embodiment, in which there are a shallow depression 2 on bottom of outer pot 1 for reserving of water,a drain valve 3 and a drain 4 on one side beneath the shallow depression 2 for drainage. A heater 5 and a temperature control breaker 6 are installed respectively on or beneath, and beneath the shallow depression 2. Shell 7 and outermost cover 8 are for ornamentation at the outermost part of cooker.

There is a fold 10 on the upper part of inner pot 9, specially for anchorage of covers.

A ring case 12 coupled with ring packing is installed and screwed on upper part of outer pot by means of several screws 13. There are several U shape cuts 14 along the inner edge of ring case 12. A ring of V shape packing 15 is fitted on the inner edge. Moreover, a few holes 16 are punched on ring case 12 for installation of pressure valves 17. Inner pot with its protuberances 11-directed right above the cuts 14 on ring plate can be lowered onto the outer pot such that the fold 10 closely touches the ring case 12 with its base inner pot 9 is then rotated to interlock and hangs on the ring case 12; neither the inner pot wall nor base will touch the outer pot wall or base, forming a space in between.

A cover assembly 18, which is composed of a upper cover 19 and a lower cover 20, is fitted at the inner center of ornamental cover 8. On the lower cover 20, there is an exhalation opening 21. A ring of V shape airtight packing 22 is fitted along the upper case 19 preventing air or steam leakage. Piercing the ornamental cover 8 and upper cover 19 is a breathing valve. When the ornamental cover 8 is put onto the cooker, the upper and lower case 19, 20 just fit on the fold 10 of inner pot 9.

A pivot 81 acts as an active joint of ornamental cover 8 which when put on-, is locked by holdfast 82; meanwhile, upper cover 19 and lower cover 20 lay right on inner pot 9. A pad 181 on the center of ornamental cover 8 is used for alleviation of pressure. When pad is pressed, cover assembly is pushed by reaction force and thereby more closely touches the fold 10 on inner pot. In case the pressure is too high, and exhalation opening 21 is not sufficiently effective, lower cover 20 will be pushed upward by means of pad 181 such that steam will be exhaled through cover edge from inner pot 9, and then through the breathing valve 23 into atmosphere.

A valve chamber 24 installed outside the shell 7 connects to the space between pots by a tube piercing the wall of shell 7 and outer pot 1.

Referring to valve chamber in Fig. 2, chamber 30 are screwed tightly with cover 31 with packing in between for leakage protection, forming a closed space. At the base of chamber 30, there is a circular opening 33 for fitting of cooling water automatic recycle valve 34 (shown in Fig. 3).

The three holes punched on cover 31 are for equipping of safety valve 35, breathing valve 36 and adjustable pressure valve 37. Safety valve consists of a cylinder 351 and a load 352. In the center of load 352 is a circular hollow slightly larger than the inner opening in cylinder 351. When space between pots suffers a pressure that, after exhalation through pressure valve and adjustable pressure valve, is still larger than that permitted by load, steam pushes the load upward and escapes through the slit, thereby ensuring safety. Breathing valve 36 is composed of a base 361, a ring lid 362 with a soft plug 365 corked in center, a movable rod 364 fitted in the center of soft plug.

The central hole 365 of soft plug 363 is slightly larger than the body 366 but smaller than the base 367 of movable rod. At initial heating, steam pressure is not large; steam mainly escapes through the slit between rod 366 and hole 365. As heating goes on, rod base 367 is pushed up by steam, and hence soft plug 363 is pressed tightly by rod base 367. This means that steam must be discharged through other valves.

The base 371 of adjustable pressure valve 37 penetrates and is mounted on the cover 31, linking with the space in chamber 30. Plug 372 has a hollow body with a cone shape tail on which there are several exhalation hole 3721, and also a protrusive head. Pad 374 also has a protrusive tail. Inserted between plug 372 and pad 374 is a spring 374. The two protrusions outside block 375 just fit the two helical grooves on guiding head 376 and can move along it.

The two channels 3771 on the inner surface of shell 377 allows the up and down motion of block 375 with its protrusions. Installed inside the shell 377 are plug 372, spring 373, pad 374, a movable block 375 and guiding head fitted on pad 374. The assembled part is then screwed to base 371, and exposing the top of guiding head 376.

Regulator 379 and wheel 378 are then screwed on. Rotation of wheel 378 turns guiding head 376 so that block 375 is triggered to move up or down the channels 3771 of shell 377 because of mutual interaction of protrusions on block 375 with helical grooves on guiding head 376. By this way, compression force in spring and hence pressure allowed can be adjusted.

Referring to the cooling water automatic recycle valve in Fig. 3, a tube 25 inserted on the hole punched on outer pot 1 is fixed by a nut 251. Tube 25, piercing outer pot 1 and shell 7, is connected to cooling water automatic recycle valve 34 which has a movable plug 341 in front.

There are several holes at the head of movable plug 341 which can move freely inside the valve. No spring is installed, and inner radius of valve is about the same as plug 341, but they have loose contact. A vertically protruded spherical plug 342 has a ball 344 which blocks the exit because of its weight. Therefore, the movable plug 341 becomes an one way cork. When steam generated in outer pot passes through tube 25, and then into automatic cooling water recycle valve 34, it pushes movable plug 341 towards and hence blocks opening 343, and so steam cannot escape through this plug, ball 344, is pushed upward by the steam which escapes through spherical plug into valve chamber 30. On meeting the ambient chamber wall, steam condenses and flow back to chamber 30. By this way; no steam and water will spray into surrounding.When heating is stopped, pressure between pots reduces, and that in chamber 30 disappears. Ball falls down because of its weight and blocks the exit. Condensed water due to pressure gradient, pushes the movable plug 341 open and flow back to the shallow depression 2 in outer pot 1 until equilibrium restored. Through this, water recycles automatically.

Referring to sectional view of valve chamber in Fig. 4, steam flows pass tube 25 and spherical plug 342 into chamber 30. At initial low pressure period, steam escapes from the slit between soft plug 363 and movable rod 364 of breathing valve. As heating goes on and pressure raises, rod body 366 of breathing valve is entirely pushed up and blocks the hole 365 with its base 367, leaving only the safety valve and adjustable pressure valve possible for exhalation. When pressure is larger than that allowed in spring 373, steam pushes 372 open and discharges. For further pressure increment, steam will discharge through safety valve 35 to ensure safety.

Referring to pressure valve in Fig. 5,it is composed of a body 171,a spring 172, a plug 173 and a screw cock 174. There are several holes 175 at the tail of plug 173. Pressed by spring 172, plug 173 blocks the screw cock 174 so that space between is isolated from surrounding.

Referring to Fig. 6, in case pressing force of steam pressure is greater than elastic force in spring, plug 173 is pushed open, and excessive steam discharges by holes 175.

With reference to the drain valve and drain in Fig.7, drain valve 3 is screwed to a rod31 which extends out of shell 7 and has a regulator 32 at the end. A drain 4 is screwed to one end of drain valve for drainage while the other end is fixed to lowest point shallow depression 2 of outer pot 1.

In Fig. 8, ring case 12 is anchored on the outer pot by means of packing (not indicated in Fig. 8) and several screws. The inner pot 9 has folds along the upper edge, and on pot wall there are several protuberances 11 which can fit and pass cuts 14 in ring case 12 such that inner pot 9 hangs on and is blocked by ring case 12. Moreover, the two pots will not touch each other, and an isolated space is forned in between.

Referring to the ring case in Fig. 9, along the inner ring of it are several cuts 14 and taped holes 16, where the former allows the fitting of protuberances 11 and the latter for installation of pressure valves 17. In some embodiment, no pressure valve and screw is installed.

Some water is added to shallow depression in outer pot and food is placed in inner pot which is then put on ring case such that protuberances just fit and pass the cuts, and inner pot hangs on the ring case with its fold. Here the lower end of fold touches the V shape ring packing, anyway, inner pot can rotate. When cover assembly is put on, fold is pressed to touch the V shape packing, forming an isolated heating space, meanwhile, another heating space is formed between pots, which is connected to valve chamber by means of a tube.

When steam is generated gradually, heating space between pots is filled with warm steam and room temperature air. They flows into the cooling water automatic recycle valve in valve chamber, since spherical plug is blocked due to ball weight provided that steam is not sufficient to push it open, movable plug is pushed forward by steam and again blocks the opening. As more steam is generated so that it has sufficiently power to push the ball up, some escape by spout in spherical plug. The opposing force in movable rod of breathing valve is the smallest among valves,thereby steam together with air discharges through this valve.

When heating goes on, movable rod is pushed and blocks breathing valve. At this moment, V shape packing between inner pot and ring case suffering the pressing of steam at its mouth, spreads gradually, finally touching closely the fold, and hence isolating the space between pots.

As more steam is generated in further heating, steam fulfills the whole space between pots, and uniformly transfers heat to inner pot base and wall. According to heat transfer mechanism, temperature difference between high temperature steam and food in inner pot is great and it is not likely to reach isothermal state in instant because of heat barrier. Therefore, heat cannot be directly transferred to inner pot, and as heating goes on, heat transfer rate cannot catch up with steam generation rate, subsequently causing increase of pressure which can be adjusted by discharging some steam through pressure valve on ring case or adjustable pressure on valve chamber. Steam exhaled through pressure valve passes slit between ornamental cover and shell in atmosphere.

By the above way, steam pressure can be maintained steady. Before steam pressure raises to criterion level, all the heat energy generated is transferred repeatedly to inner pot, and raises food temperature. This action repeats again and again until steam pressure reaches criterion level. In other words,food temperature will raise in every interval between stead exhalation.

When food and inner pot temperatures raise gradually, the heat transfer barrier disappears. From this noment on, heat is directly transferred to inner pot and then food, giving fastest heat response.

Steam generated in inner pot during boiling flows through he exhalation opening, and detours to the breathing valve on upper cover, and is finally discharged into air.

The breathing valve can ensure steam generated is not completely discharged into air but retains for some time in pot. As more steam is generated and cannot escape from inner pot, it will press the V shape mouth of V shape packing ring on outer boundary of upper cover, forming a tight contact and a perfect isolated heat space. In case too much steam are generated, buffer pad in cover assembly will be pressed and pushed up, and thereby steam escapes form slit along cover boundary into upper cover, and then by breathing valve into air.

When heating is terminated, steam will be exhaled by exhalation valve for a certain time. This action will slow down and finally stop so that a certain amount of steam and heat can retain in inner pot and steam food.

Atmospheric air will slowly flow into inner pot by breathing valve, balancing the pressures on two sides of cover assembly.

On termination of heating, breathing valve can assist and keep the cover in close contact for some time, remaining some steam for further steaming when pressure between pots reduces, movable rod is no long under pressing of steam and falls, permitting air inflow.

Moreover, ball in spherical plug of cooking water automatic recycle valve falls also due to its weight, and blocks the exit. Condensed water compelled by influx air flows and pushes open horizontal movable plug, and flows back to shallow depression in outer pot. It eliminates the problem of water accumulation in valve chamber.

Because of uniform and indirect heating by steam, every part of food in inner pot can be boiled under same temperature and pressure. In addition, as food is heated step by step, its tastes, deliciousness and nutrition can be perserved, and steam is effectively used, and hence it can shorten cooking time and save energy.

Since heater, temperature control breaker or tines mentioned in one of the embodiments are all preliminary technology, they will not be discussed here.

Compulsory accessories,i.e. breathing valve safety valve and cooling water automatic recycle valve, cooperated with pressure valve or adjustable pressure valve can effect as described in embodiments. Pressure valve and adjustable valve can both be installed. The sequence of criterion pressure level for working of valve is safety valve > pressure valve > = maximum adjustment of adjustable pressure valve > breathing valve. Spherical plug and movable plug of cooling water automatic recycle valve are respectively for exhalation and influx; both of them are one way valve.

The above explanation is based on an embodiment; by no means will it resist the area of this invention. Any extension, alternation or ornamentation originated from this principal are considered to be within this patent area.

In conclusion, this is a new and practical invention, and matches the application requirements of patent.

Claims

1. A uniform heating responsive steam cooker is composed of an outer pot with a shallow depression, a drain valve and a drain which is linked to the base of shallow depression, an inner pot with fold along edge and protuberances on pot wall, a ring case with packing screwed to and fitting the fold on outer pot on which there are several taped holes, and along the inner edge of ring case are several cuts which permits the passage of protuberances on inner pot, a V shape packing ring fitted on ring case, a cover assembly consists of an outer and an inner pot when put on, and installed along the edge of outer pot is V shape packing for leakage protection, a tube which pierces outer pot and connects to cooling water automatic recycle valve in valve chamber, a valve chamber which is composed of safety valve, breathing valve, adjustable pressure valve and cooling water automatic recycle valve, and the chamber room is composed of a empty box and a cover, with packing screwed on it, and a circular opening punched at the bottom is fitted with a tube which has cooling water automatic on its end,and a safety valve consists of a cylinder and a load,under which is a hollow with a diameter slightly larger than the outer diameter of cylinder, and a breathing valve has it base screwed to the cover of valve chamber, and screwed to the base is a nut, and a rod fitted in the hole of a soft plug on top, and the rod has a body of cylindrical shape having smaller size than the plug hole and a bulky head and tail; the above parts are assembled in which valve chamber is installed outside the outer pot, using a tube to connect it to the inner space by piercing the outer pot.The cuts on ring case allow the passage of inner pot and its protuberances, such that fold on inner pot touches the V shape packing ring, and when turned, inner pot protuberances are interlocked with cuts, and inner pot hangs on ring case without touching the outer pot, thereby forming a heating space between pots. It is particularly characterized by it uniform heating by heat transfer from steam.

2. According to area mentioned in claim 1, adjustable pressure valve installed on valve chamber has a base locked on cover of valve chamber, and a cylindrical plug with several exhalation holes at its cone tail and protrusive head, and a pad with protruded base, a spring inserted and fixed between pad and plug, a block with several protrusions, and a guiding head having several helical grooves which allow the motion of block protrusions, and a shell with several vertical channels which allow the up and down notion of protrusions, and a regulator and wheel. Shell is screwed to base, and installed in it are plug, spring, pad, block and guiding head which has it head exposed outside, and regulator and wheel are then screwed on.The rotation of wheel will turn the guiding head and subsequently the up and down motion of block along channels of shell due to interaction of block protuberances and grooves, and there by compression of spring and pressured allowed by valve are adjusted.

3. According to area mentioned in claim 1, the front side of cooling water automatic recycle valve is a movable plug, and the other end is linked to a tube connecting to inter pot space. At the head of movable plug has several holes, and no spring is installed. This movable plug can move horizontally and freely, having a size in according to the inner diameter of valve.A vertical spherical plug on this valve is blocked by its ball because of weight.

When steam pressure is great, movable plug is pushed forward and blocks the holes. Therefore steam is trapped and it turns to push the ball up and escapes. When it is cooled down, pressure in interpots reduces, and because pressure is higher flow back to shallow depression in outer pot by pushing open the movable plug.

4. According to area mentioned in claim S, cooling water automatic recycle valve, safety valve and breathing valve are compulsory accessories;they work in cooperation with a few pressure valves.

5. According to claim 1, the cooker can be operated with cooling water automatic recycle valve, safety valve, breathing valve and adjustable pressure valve without installation of pressure valve.

6. According to claim 1, the cooker has a safety valve, a breathing, an adjustable pressure valve and a pressure valve, which allows different cooking methods.

7. According to claim 1, drain valve is installed at a side of bottom of shallow depression, convenient for cleaning.

8. As mentioned in claim 1, a valve chamber which includes a safety valve, breathing valve, adjustable pressure valve and cooling water automatic recycle valve is a characteristic of invention.