WO2001026517A1

WO2001026517A1 - Heat pipe cookware

Info

Publication number: WO2001026517A1
Application number: PCT/KR2000/001130
Authority: WO
Inventors: Youngman Chung; Byungsook Jin; Jaekyoon Kim
Original assignee: Youngman Chung; Byungsook Jin; Jaekyoon Kim
Priority date: 1999-10-11
Filing date: 2000-10-10
Publication date: 2001-04-19
Also published as: KR200175044Y1

Abstract

The present invention relates to a heat pipe cookware for cooking a food better by heating the whole part of the cookware at a uniform temperature. More particularly, the present invention relates to a heat pipe cookware having a characteristic to heat the whole part of the cookware at a more uniform temperature by forming a plural number of protuberances in the heat pipe so that the circulating length of a hydraulic fluid gets to be short.

Description

heat Pipe Cookware

Field of the Invention

The present invention relates to a heat pipe cookware for cooking better food by heating the whole part of the cookware at a uniform temperature. More particularly, the present invention relates to a heat pipe cookware having a characteristic to heat the whole part of the cookware at a more uniform temperature by forming a plural number of protuberances m the heat pipe so that the circulating length of a hydraulic fluid gets to be short.

Background of the Invention

The operational principles and the structure of the conventional heat pipe cookware are below described in details by reference to Fig. 1. Fig. 1 is a schematic sectional view of the conventional heat pipe cookware.

By and large, the cookware comprises an inner plate 3 in which food 7 is put, and an outer plate 1. The inner plate 3 and the outer plate 1, which are made of metal, are joined together, being kept at a given interval therebetween. Thus, an airtight space 2, which is completely isolated from the outside thereof, gets to oe formed with it being enclosed by both plates. A wick 5, a hydraulic fluid 6 and a screen 4 are provided in the airtight space 2.

The wick 5 is located at the center of the airtight space 2, the screen 4 is installed a little away from the bottom thereof, and the hydraulic fluid 6 is filled up to the height of the screen 3.

SUBSTTTUTE SHEET (RULE 26) hen cooking starts, the heat is transferred from the bottom of the airtight space in the arrow direction 8, and this heat is useα to vaporize tne hydraulic fluid in the airtignt space 2. The airtight space 2 is filled up with the vaporized hydraulic fluid, wnich transfers tne heat to the _nner plate 3 and then gets to be condenseα. The condensed hydraulic fluid 6 gets to ioe collected at the _ower center of the airtight space 2 by means of gravity and/or the capillary pressure of the screen 4 and the wick 5. Then, the nydraulic fluid, wnich is collected so, is vaoor_zed again therein, and thereby, it is circulated in the airtight space 2. Wherein, thermal equilibrium is attained in tne airtight space 2 by sucn vaporization and condensation of the hydraulic fluid, and thereby, the uniform heat gets to be transferred to the inner plate 3. Such transferred heat enables the food 7 contained in the cookware to be cooked at an almost uniform temperature. That _s to say, even if the cooκware is heated locally, food is heated uniformly so that it is cooked well. However, since in the conventional heat pipe cookware, the interval oetween the inner plate and tne outer plate which form tne airtight space 2 is uniform without anything protuberant from either of both plates, the circulating loop of the hydraulic fluid is long. Therefore, the flowing length of the hydraulic fluid and the circulating amount per the loop 9 gets to be long and large respectively, which limits the maximum heat transfer disadvantageously . Besides, since the circulating loop 9 is long, there are some problems that the circulating loop happens to be interrupted on the way and the bottom gets to be dry (alias, capillary limit) .

Furthermore, tnere is a case that the surface tension and the latent heat of vaporization of the hydraulic fluid get to be small, depending upon the kind of hydraulic flαid and/or the size of the coo ware. If so, the total requirement for circulating the hydraulic fluid for cooking gets to be augmented, but the liquidity of the hydraulic fluid gets to be lowered due to the insufficient capillary pressure, and as a result, the heat fails to be transferred promptly and uniformly.

This failure causes a problem that the cookware is partially overheated.

Object of the Invention

The present invention has been devised m order to provide solutions to the said problems. The primary object of the present invention is to provide a heat pipe cookware making the heat distributed uniformly m the whole cookware and further the hydraulic fluid circulated smoothly by snortenmg the circulating loop of the hydraulic fluid, which exists in the heat pipe.

The secondary object of the present invention is to provide a heat pipe cookware enabling any of the various kinds of hydraulic fluids to be available by making the heat circulated smoothly m the heat pipe.

The said objects of the present invention are acmeveα by a heat pipe cookware comprising an inner plate 23 m which food 27 is put; an outer plate 21 whicn is joined with the said inner plate 23, forming an airtight space 22 enclosed by the outer plate and the said inner plate 23; a screen 24 which is installed m the lower part of the said airtight space 22, and where a plural number of through holes are formed so that the surface tension thereof may be high; a hydraulic fluid with which the said airtight space 22 is filled at least as mucn as the said screen 24 is soaked therein; and an obstructive means for obstructing the circulation of tne said hydraulic fluid by protruding it from the said inner plate 23 and/or tne said outer plate 21 inward to the said airtight space 22.

And, the said obstructive means is preferaoly at least one or more ring-type protuberances 20 as formed in the lower part of the cookware wnere the said hydraulic fluid is collected. Also, it is possible to install two pairs of tne said protuberances 20 respectively m the outer face of the said inner plate 23 and the inner face of the said outer plate 21.

Wherein, it is preferable that a WICK is further installed at the center of the said airtight space 22.

In addition, it is also preferable that the said obstructive means is of plural protuberant pieces 30 as protruded from the inner face of the said outer plate 21 toward tne said airtight space 22 to a given height and formed ir the circumferential direction.

And, the said protuberant pieces 30 can be formed at least m two rows or more m the radial direction of the said cookware.

Also, a wick can be further formed at the center of the said airtight space 22.

Brief Description of the Drawings

Fig. 1 is a schematic sectional view of the conventional heat pipe cookware.

Fig. 2 is a sectional view of the heat pipe cookware as the first embodiment according to the present inventio .

SUBSTTTUTE SHEET (RULE 26) Fig. 3 is a sectional view of the heat pipe cookware as the second embodiment according to the present invention .

FIG. 4 is a sectional view taken along the line A-A of Fig. 3.

Detailed Description of the Invention The respective embodiments according to the present invention are below described m details by reference to the figures attached hereto. Fig. 2 is a sectional view of the heat pipe cookware as the first embodiment according to the present invention. As illustrated m Fig. 2, the heat pipe cookware comprises largely the inner plate 23, the outer plate 21, the screen 24, the hydraulic fluid 26 and the

The inner plate 23 is made of metal, which is l~3mm thick, such as aluminum, copper, stainless steel or the like. The inner plate 23 can contain food 27 like a pan, a frying pan, etc. The outer plate 21 is made of the same metal material as the inner plate 23, and it is tightly joined witn the inner plate 23 by using the welding method as shown in Fig. 2. A given interval (approximately 10mm) is kept between the outer plate 21 and the inner plate 23, and the space enclosed by both plates gets to be the airtignt space 22 which is completely isolated from the outside thereof .

The airtight space 22 is kept vacuumized, and it holds the hydraulic fluid 26, the screen 24, the wick 25 and the ring-type protuberance 20.

The surface of the hydraulic fluid 26 is indicated

SUBSTTTUTE SHEET (RULE 26) as an inverted triangle indicating the water level n Fig. 2. Theoretically, any pure matter suffices for the hydraulic fluid, but actually, it requires a high surface tension and a low viscosity in order to augment the capillary pressure. Also, even though the circulating amount of the nydraulic fluid 26 is small, it requires a large latent heat of vaporization m order to transfer a large amount of heat. And, if the internal pressure of the airtight space 22 is excessively nign, it is dangerous. Thus, j.t is preferable that the airtight space 22 has a vapor pressure of 1 atmospheric pressure or less around 100°C. If the cookware is heated without food 27 contained therein so that it is overheated at 200°C or so, the vapor pressure should be able to be maintained below a few atmospheric pressure. In addition, the hydraulic fluid requires no combustibility, non-toxicity to the human body and environment-friendliness in order to prevent any accidental risk when the hydraulic fluid leaks. A typical hydraulic fluid 26 meeting such requirements is water. The screen 24 is made of a metal material in which a plural number of through holes are formed, which is fixed to the lower part of the airtight space 22 by the spot welding method. Wherein, the screen 24 is not attached closely to the bottom of tne outer plate 21 but fixed to the outer plate with it being away from the bottom thereof by a given height. This height is approximately identical with the water level of the hydraulic fluid 26. The screen 24 makes the hydraulic fluid 26, which has been condensed by the capillary action, distributed evenly m the bottom of the airtight space 22.

The wick 25, which is of a column type, is installed

SUBSTTTUTE SHEET (RULE 26) at the center of the lower part of the airtight space 25. And, like the screen 24, the wick 25 makes the hydraulic fluid 26, which has been condensed by the capillary action, distributed evenly in the bottom of the airtight space 22.

The ring-type protuberance 20 is protruded from the outer face of the inner plate 23 toward the airtight space 22 to a given height, and it is also protruded from the inner face of the outer plate 21 toward the airtight space 22 to a given height. Two pairs of ring-type protuberances 20 are protruded respectively from the inner plate and the outer plate so that one pair of ring-type protuberances 20 thereof may be located at one concentric circle around the wick 25, while the other pair of ring-type protuberances 20 may be located at another concentric circle around the wick 25. Such ring-type protuberances can be made mechanically during the work for processing the inner plate and the outer plate respectively, and they can be also formed by welding the respective metallic lines thereinto. And, such ring-type protuberances 20 can be formed in three rows or more, depending upon the size of the cookware and/or the characteristic of the hydraulic fluid.

Fig. 3 is a sectional view of the heat pipe cookware as the second embodiment according to the present invention. As illustrated in Fig. 3, the second embodiment is similar to the first embodiment in its constitution of the inner plate 23, the outer plate 21, the screen 24, the hydraulic fluid 26 and the wick 25. The difference between the first embodiment and the second embodiment is that the protuberant pieces 30 instead of the ring-type protuberances 20 are formed in the second embodiment. Each protuberant piece 30 is protruded from the inner face of the outer plate 21 toward the airtight space 22 to a given height. This height of the protuberant piece 30 is as much as it does not reach the inner plate 23. Fig. 4 is a sectional view taken along the line A-A of Fig. 3. As illustrated in Fig. 4, a plural number of protuberant pieces 30 are arranged around the wick 25 in the first circular row, and further, other plural protuberant pieces 30 are arranged around the wick 25 in the second circular row. The protuberant pieces 30 can be also arranged m a polygonal row, such as a triangular, a quadrangular or a sex angular row, or a curved row. The locations where the protuberant pieces 30 are arranged and the number and the size of protuberant pieces can be adjusted properly depending upon the size of the cookware and/or the characteristic of the hydraulic fluid.

The action and the effect of the present invention are below described in details by reference to the constitution of the first embodiment and the second empcdiment as described above.

When the cookware is heated in the arrow direction 8 as shown in Fig. 2 and 3, m the first place, the heat is transferred through the outer plate 21 to the hydraulic fluid 26. Then, as the hydraulic fluid, which is collected around the wick 25 and the screen 24, is heated, it starts to oe vaporized.

The airtight space 22 is first filled up with the vaporized hydraulic fluid 26.

Then, the vaporized hydraulic fluid is saturated. Further, as the saturated hydraulic fluid is condensed, it starts back to be liquefied. The liquefied hydraulic fluid

26 rolls down the vertical walls of the inner plate 23 and

SUBSTTTUTE SHEET (RULE 26) the outer plate 21. As the hydraulic fluid 26, which have rolled down so, is vaporized again, the circulating loop 29 is formed. That is to say, thermal equilibrium is attained in the airtight space 22, where liquid and vapor coexist. Thereby, as the inner plate 23 is heated at a uniform temperature, the food 27 held by m the inner plate is cooked.

Wherein, as the vaporized hydraulic fluid 26 is collected by colliding against the ring-type protuberances 20 or the protuberant pieces 30, it is condensed, and thereby the circulating loop 29 is short. Also, as the hydraulic fluid 26, which has been condensed and further rolls down the walls of the inner plate and the outer plate, it is vaporized before it gathers around the center of the airtight space 22 by colliding against plural protuberances 20 or protuberant pieces 30, the circulating loop 29 is short. That is to say, comparing with the conventional heat pipe cookware, a plural number of circulating loops 29, which are short n their circulating _ength, take place in the heat pipe cookware according to the present invention.

The neat pipe has the characteristic that as the requirement for circulating the hydraulic fluid is large, the maximum heat transfer amount gets to be small, and as the length of the circulating loop gets to be long, the maximum heat transfer amount gets to be small. Therefore, as the length of the circulating loop gets to be short, the maximum neat transfer amount gets to be augmented, and thereby, it is possible to heat the cookware rapidly. Such plural circulating loops 29 have an effect to enable the heat to be transferred and distributed more uniformly m tne cookware. In the actual test, the temperature difference between the inner plate 23 and the outer plate 21 has been found to be maximally 1°C or so, and the temperature deviation in the inner plate 23 has been found to be 0.1°C. Since such temperature differences are, actually, very small, it will not matter to assume that a uniform temperature should Pe maintained therein.

In addition, typical examples of the cookware to which the heat pipe according to the present invention is applicable are a frying pan, a rice pot, a pan, and the like.

According to the present invention as above described, the neat pipe cookware has the advantages of making the heat distributed uniformly in the whole cookware and further the hydraulic fluid circulated smoothly in the heat pipe by shortening the circulating loop of the hydraulic fluid which exists m the heat pipe. Therefore, the heat pipe cookware according to the present invention has the characteristic that food can be cooked uniformly. Also, since the circulating loop of the hydraulic fluid is short and a plural number of circulating loops take place, the maximum heat transfer amount gets to be so large that food can be heated rapidly.

Further, since heat is circulated smoothly m the heat pipe, various kinds of hydraulic fluids are available as a hydraulic fluid therein.

Even though the present invention has been described and illustrated herein by reference to only the preferable embodiments as above mentioned, the present invention can be variously modified and embodied m various forms within the gist and scope of the present invention. Therefore, it should be understood that this invention is not limited to -li¬

the specific embodiments as described above, and that this invention includes all modifications, equivalents and substitutes within the spirit and scope of this invention as defined in the "Claims" attached hereto.

SUBSTTTUTE SHEET (RULE 26)

Claims

What is claimed is;

1. A heat pipe cookware comprising; an inner plate 23 in which food 27 to be cooked is put; An outer plate 21 which is joined with the said inner plate 23, forming an airtight space 22 enclosed by the outer plate and the said inner plate 23; a screen 24 which is installed in the lower part of the said airtight space 22, and where a plural number of through holes are formed so that the surface tension thereof may be high; a hydraulic fluid with which the said airtight space 22 is filled at least as much as the said screen 24 is soaked therein; and an obstructive means for obstructing the circulation of the said hydraulic fluid by protruding itself from the said inner plate 23 and/or the said outer plate 21 inward to the said airtight space 22.

2. The heat pipe cookware according to Claim 1, wherein the said obstructive means is at least one or more ring-type protuberances 20 as formed in the lower part of the cookware where the said hydraulic fluid is collected.

3. The heat pipe cookware according to Claim 2, wherein two pairs of the said protuberances 20 are xnstalled respectively in the outer face of the said inner plate 23 and the inner face of the said outer plate 21.

4. The heat pipe cookware according to Claim 3, wherein a wick is further installed at the center of the said airtight space 22.

SUBSTTTUTE SHEET (RULE 26)

5. The heat pipe cookware according to Claim 1, wherein the said obstructive means is of plural protuberant pieces 30 as protruded from the inner face of the said outer plate 21 toward the said airtight space 22 to a given height and formed in the circumferential direction.

6. The heat pipe cookware according to Claim 5, wherein the said protuberant pieces 30 are formed at least in two rows or more in the radial direction of the said cookware.

7. The heat pipe cookware according to Claim 6, wherein a wick is further formed at the center of the said airtight space 22.

SUBSTTTUTE SHEET (RULE 26)