A device for uniform heating of the bottom of a pot

Abstract

This invention discloses a heat equalization device for the bottom of a pot, belonging to the field of cookware technology. The device includes a contoured cover adapted to the outer contour of the pot's bottom, with numerous through-holes. The cover is fixed to the outer side of the pot's bottom, forming a semi-open heat equalization cavity between it and the pot bottom. This device can effectively block open flames even when the aperture is larger than the static critical flame quenching diameter. Through the synergistic effect of the cavity's back pressure and the flame quenching via the through-holes, combined with radiative heat transfer, flameless combustion heat release, and convective heat transfer, it achieves uniform heating of the pot bottom. This device effectively solves the problem of localized overheating at the pot bottom, reduces food sticking and scorching, and features low thermal inertia and rapid heat response, making it suitable for Chinese stir-frying and deep-frying scenarios.

Description

Technical Field

[0001] This invention relates to the field of cookware technology, and more specifically to a bottom-mounted heat-dissipating device adapted to open-flame cooking pots. Background Technology

[0002] Existing open-flame heating methods for pots generally suffer from the problem of flames concentrating in the center of the pot bottom, leading to localized overheating and food easily sticking and burning. To address this issue, various heat-distributing plates, composite-bottom pot bodies, and heat-concentrating covers have emerged on the market, but all have significant drawbacks:

[0003] 1. Traditional cast iron heat spreaders use a thick metal plate structure and rely on the thermal conductivity of the metal itself to achieve uniform heat distribution. They have high thermal inertia, slow heating, and sluggish heat response, making them unsuitable for cooking scenarios that require rapid temperature control, such as Chinese frying and stir-frying. They also have low thermal efficiency, increase gas consumption, and have poor radiant heat exchange effect, resulting in insufficient uniform heat distribution.

[0004] 2. The composite bottom pot body adopts a multi-layer composite structure of "stainless steel-aluminum-stainless steel", which is complex and has high manufacturing cost. After long-term high-temperature use, due to the difference in thermal expansion coefficients of different metals, problems such as composite layer detachment and pot bottom deformation are prone to occur, resulting in a short service life. Moreover, it still cannot fundamentally solve the problem of local overheating caused by direct exposure of the pot bottom to an open flame.

[0005] 3. When a flame concentrator is placed over the burner head, it can only concentrate the flame and reduce heat loss. It cannot change the heating method of the open flame directly hitting the bottom of the pot. The effect of evenly distributing the flame is limited. In addition, some flame concentrators can lead to incomplete combustion, increase CO emissions, and pose safety hazards.

[0006] 4. Existing technologies guide the design of open flame blocking applications based on the premise that "the aperture must be smaller than the static critical flame quenching diameter to achieve open flame blocking." This does not take into account the pressure difference between the two ends of the through hole, resulting in most related applications, especially those in high-temperature environments, limiting the aperture to an extremely narrow range of less than 1.0 mm. In cookware applications, this makes processing difficult, prone to clogging, and difficult to implement in practice. Summary of the Invention

[0007] The purpose of this invention is to overcome the above-mentioned defects of the prior art and provide a pot bottom uniform flame device. Based on the flame quenching effect of the through holes in the cover and the back pressure of the cavity to prevent open flame impact, combined with multiple heat exchange methods, it effectively solves the problem of local overheating caused by open flame directly hitting the bottom of the pot.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A heat equalization device for the bottom of a pot includes a contoured cover that is adapted to the outer contour of the bottom of the pot; the contoured cover is densely covered with several through holes; the contoured cover is fixed to the outside of the bottom of the pot and forms a semi-open heat equalization cavity between it and the bottom of the pot.

[0010] This device uses the stabilizing back pressure formed by the heat-spreading chamber and the flame quenching effect of the through hole to jointly prevent the open flame from directly contacting the bottom of the pot. At the same time, it utilizes the radiative heat exchange of the contoured cover, the flameless combustion heat release in the heat-spreading chamber, and the convective heat exchange of high-temperature flue gas to achieve uniform heating of the bottom of the pot.

[0011] Furthermore, the flame quenching effect, in conjunction with the cavity stagnation back pressure, allows the through-hole diameter to be larger than the static critical flame quenching diameter under the corresponding working conditions, reducing processing difficulty and the risk of blockage.

[0012] Furthermore, the thickness of the contoured cover ranges from 0.5mm to 3.0mm, preferably from 1.0mm to 1.5mm.

[0013] Furthermore, the diameter of the through holes ranges from 0.2 mm to 8.0 mm, preferably from 0.5 mm to 3.0 mm; the hole diameters can be combined according to their distribution positions, with a gradient distribution structure of larger central hole diameter and smaller edge hole diameter being preferred. It should be noted that the distribution position of the through holes is not a core protection point of this invention.

[0014] Furthermore, the through-hole can have any suitable geometric shape. For non-circular through-holes, its diameter is calculated as the hydraulic diameter, and the formula for calculating the hydraulic diameter is: Dh = 4A / P, where A is the cross-sectional area of ​​the through-hole and P is the inner circumference of the through-hole. It should be noted that the specific shape and formation method of the through-hole are not part of the core protection points of this invention.

[0015] Furthermore, the through holes are distributed throughout the contoured cover, and can be uniformly or non-uniformly distributed. The distribution shape of the through holes is only a preferred embodiment and is not a key point of protection of this invention.

[0016] Furthermore, the conformal cover should be made of a material with good thermal conductivity, catalytic activity, high temperature resistance, and corrosion resistance to ensure the stable occurrence of flame quenching. As a preferred embodiment, the conformal cover is made of a metallic material, preferably 310S stainless steel. It should be noted that the specific material of the conformal cover is only a preferred embodiment and is not a key point of protection of this invention.

[0017] Furthermore, the contoured cover can be fixed to the outer side of the bottom of the pot body in any suitable manner. It should be noted that the specific method of fixing the contoured cover is not a core aspect of this invention.

[0018] Furthermore, the thickness of the semi-open heat equalization cavity ranges from 0.2mm to 8.0mm, preferably from 1.0mm to 3.0mm, and the thickness of the heat equalization cavity can be uniform or gradually transition to the edge of the connection between the cover and the pot body.

[0019] Furthermore, the device does not have a solid heat-conducting interlayer covering the main area of ​​the heat equalization cavity, and does not use solid heat conduction as the main heat equalization method, thus solving the problems of large thermal inertia and slow fire response of traditional heat equalization devices.

[0020] It should be noted that this invention does not exclude the inclusion of any local solid structures within the conformal cover or heat spreader, including but not limited to reinforcing ribs, connecting columns, positioning structures, and sealing structures. As long as these local solid structures do not cover the main area of ​​the heat spreader and do not constitute the main heat spreader method, they still fall within the protection scope of this invention.

[0021] The core of this invention lies in abandoning the design concept of traditional uniform heating devices that "uses physical heat conduction as the main uniform heating method" and instead adopting a multi-synergistic uniform heating method of "radiation + flameless combustion + convection", thereby achieving a unity of low thermal inertia, rapid response and high uniform heating effect.

[0022] Working principle

[0023] This device relies on a complete closed loop of "gas jet through-hole air intake—cavity stagnation back pressure + through-hole quenching flame arrestor—cover body radiation + flameless combustion + high-temperature flue gas convection synergistic heat exchange—edge through-hole exhaust" to achieve uniform heating of the pot bottom, reduce local high temperatures, and reduce food sticking and scorching. The entire principle is logically consistent and fits the actual working conditions of the fully through-hole structure, as detailed below:

[0024] 1. Basic power source: Gas jet through-hole air intake

[0025] The gas supplied by the stove body burns at high speed, forming a gas jet with high kinetic energy. At the same time, it carries a mixture of high-temperature flue gas and incompletely burned components, forming a mixed airflow. The kinetic pressure of this gas jet is greater than the sum of the passage resistance of the through holes and the stagnant back pressure in the heat spreader, which can push the mixture of high-temperature flue gas and incompletely burned components through the dense through holes on the contoured cover and into the narrow heat spreader between the cover and the bottom of the pot.

[0026] The mixture of high-temperature flue gas and incompletely combusted components inside the cavity, along with the high-temperature enclosure below that is directly impacted by the flame, provides the basis for subsequent heat exchange and combustion.

[0027] 2. Key to flame arrest: The synergistic effect of cavity back pressure and flame quenching

[0028] A mixture of high-temperature flue gas and incompletely combusted components continuously flows into the narrow soaking chamber. The gas within the chamber can only escape through a dense network of perforations. These perforations themselves exert a certain degree of throttling damping, and the small volume of the chamber prevents rapid gas escape, thus creating a stagnant back pressure within the chamber. This stagnant back pressure is in the opposite direction to the flame propagation, generating a continuous reverse resistance to the open flame and burning free radicals attempting to penetrate the perforations, thus hindering the upward propagation of the open flame.

[0029] Meanwhile, the pore walls of the through holes have good thermal conductivity and catalytic effect. When active free radicals in the flame (such as OH·, H·, O·, etc.) collide with the pore walls, they will be catalytically recombine with the through hole surface to form stable molecules, or lose their reactivity through energy transfer, thereby interrupting the combustion chain reaction and achieving flame quenching.

[0030] The combined effect of physical blocking of back pressure and chemical blocking of flame quenching ensures that even if the diameter of the through hole is larger than the static critical flame quenching diameter under the corresponding working conditions, it can still effectively prevent the open flame from penetrating the through hole and entering the cavity, thus avoiding direct contact between the open flame and the bottom of the pot and alleviating the problem of local overheating. At the same time, it does not affect the absorption of heat from the open flame and the radiative heat exchange of the contour cover.

[0031] 3. Airflow circulation and heat exchange: Synergistic heat exchange of shroud radiation + flameless combustion + high-temperature flue gas convection.

[0032] The high-temperature flue gas and the mixture of unburned components that enter the heat spreader undergo preliminary convective heat exchange with the bottom of the pot in the confined space of high temperature. At the same time, the gas in the cavity is continuously heated, and its temperature rises and its density decreases.

[0033] Meanwhile, the mixture of high-temperature flue gas and incompletely combusted components entering the soaking chamber contains unburned hydrocarbon components and residual active groups, along with a certain amount of primary mixed air (oxygen). The soaking chamber is in a high-temperature confined environment with no open flame front (blocked by back pressure and quenching), thus the incompletely combusted components undergo a flameless oxidation reaction (flameless combustion) within the chamber. This flameless combustion has no obvious flame, and the combustion temperature is uniform, which not only further improves the completeness of gas combustion, reducing energy waste and pollutant emissions, but also generates high-temperature heat to directly heat the gas inside the chamber and the bottom of the pot.

[0034] After the contoured cover is evenly heated by the open flame below, it forms a high-temperature planar radiant body that emits uniform radiant heat towards the bottom of the pot. The radiant heat is buffered by the air gaps in the heat spreader, making it more gentle and uniform and preventing localized overheating.

[0035] High-temperature gases, relying on overall thermal buoyancy, naturally convection upwards and outwards, forming a uniform convective flow field. This allows the high-temperature flue gas and the hot gases generated by flameless combustion to evenly cover the entire bottom of the pot, achieving comprehensive and uniform convective heat transfer. The synergistic effect of radiant heat from the enclosure, heat generation from flameless combustion, convective heat transfer from high-temperature flue gas, and thermal buffering from the heat-spreading chamber further enhances the uniformity of heating at the bottom of the pot, weakens localized hot spots, and makes the temperature more consistent over a larger area of ​​the pot bottom, effectively solving the problems of localized overheating and food sticking to the pot and burning.

[0036] After heat exchange, the gas temperature decreases and the density increases. Driven by thermal buoyancy convection, it is discharged outward through the through holes on the upper edge of the cover, realizing a complete through-flow airflow cycle of "intake-heat exchange-exhaust". There is no need to set up separate inlet or outlet ports, and all gas exchange is completed by relying on the through holes throughout the area.

[0037] 4. Negative feedback mechanism: ensuring operational stability

[0038] This device employs a unique negative feedback mechanism: within a certain aperture range (0.3mm to 8.0mm), the larger the aperture, the greater the air intake of a single through-hole, the higher the stagnant back pressure within the heat spreader, the greater the reverse resistance to flame penetration, and the stronger the effect of hindering flame penetration. This negative feedback mechanism enables the device to achieve open flame isolation over a wide aperture range, preventing the flame from directly impacting the pot body. Even if a small amount of open flame passes through the through-hole, the buffering effect of the heat spreader significantly reduces localized overheating.

[0039] Beneficial effects

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] 1. Innovative flame arrestor mechanism: Breaking through the limitations of traditional designs that rely solely on a single flame for quenching, a flame arrestor mechanism that combines cavity back pressure with flame quenching is proposed. This allows the diameter of the through hole to be larger than the static critical flame quenching diameter, reducing processing difficulty and the risk of blockage.

[0042] 2. Good heating uniformity: The integrated contoured cover provides radiative heat exchange, the confined cavity provides flameless oxidation heat release, and the high-temperature flue gas provides convective heat exchange. Combined with the heat buffering effect of the heat equalization cavity, it effectively improves the local high temperature defects caused by the concentrated direct flame hitting the bottom of the pot, and reduces the problems of food burning and sticking to the pot due to uneven heating.

[0043] 3. Fast thermal response: It abandons the solid heat-conducting sandwich structure that covers the main area of ​​the heat-spreading cavity, resulting in low overall thermal inertia, fast heating speed, and sensitive heat adjustment, making it suitable for different cooking scenarios such as frying, stir-frying, etc.

[0044] 4. Safe and reliable structure: There is no risk of gas accumulation in the device. Even if a small amount of unburned gas overflows from the heat spreader, it will be immediately ignited by the open flame below. The overall structure is compact and not easily deformed under high temperature conditions. It requires less change to the shape and processing technology of conventional pot bodies, which facilitates mass production and wide compatibility with various open flame pot bodies. Attached Figure Description

[0045] Figure 1 This is a partial sectional view (including a partial enlarged view) of the cookware with a uniform heat distribution device according to the present invention.

[0046] Figure 2 This is a bottom view of the cookware with a heat equalization device according to the present invention;

[0047] Figure 3 This is a top view of the cookware with a heat equalization device according to the present invention.

[0048] Explanation of reference numerals in the attached drawings: 1-pot body, 2-contour cover, 3-through hole, 4-heating chamber, 5-connecting flange (connecting structure). Detailed Implementation

[0049] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0050] Example 1

[0051] As shown in Figures 1-3, this embodiment is designed for conventional high-temperature cooking using household natural gas, with methane as the main component of the gas. The contoured cover 2 is made of 310S stainless steel, and the diameter of the through holes 3 on the contoured cover 2 is 1.5mm. The through holes 3 are evenly distributed in a ring with a spacing of approximately 6.0mm. The thickness of the contoured cover 2 is 1.5mm. The air gap thickness of the heat dissipation chamber 4 is 3mm at the center, gradually transitioning to 0mm at the edge. The edge of the pot body 1 is fixed to the contoured cover 2 by pressing together with the connecting flange 5.

[0052] In this embodiment, the diameter of the through-hole on the conformal cover is 1.5 mm, which is larger than the static critical flame quenching diameter of methane at 600℃ (approximately 1.2 mm) given in combustion science literature (measured under ideal experimental conditions of infinitely thick walls and infinitely long channels). It should be noted that in the actual structure of this device, the length of the through-hole is equal to the wall thickness of the conformal cover. Because the flame cannot complete a sufficient heat exchange process within a finite length, its actual effective critical flame quenching diameter will be smaller than the ideal value for an infinitely long channel. This embodiment, through the synergistic effect of the quenching effect and the stabilizing back pressure of the heat spreader, effectively prevents the open flame from penetrating the through-hole and impacting the pot body, even if the actual through-hole is larger than the static critical flame quenching diameter, thus suppressing localized high-temperature hotspots.

[0053] The general working process of this device is as follows: The combustion gas burns below the contoured cover 2, and the resulting high-temperature flue gas forms a mixture with the incompletely combustible gas. This mixture flows into the semi-open heat exchanger 4 between the contoured cover 2 and the pot body 1 through multiple through holes 3 on the contoured cover 2. The mixture is restricted by the throttling damping of the through holes and the narrow volume of the cavity, forming a stagnant back pressure in the heat exchanger 4. This back pressure, combined with the flame quenching effect of the through holes 3, prevents the open flame from contacting the bottom of the pot body 1. The incompletely combusted components in the heat exchanger 4 undergo a flameless oxidation reaction under the high-temperature restricted environment, generating stable heat. After being heated by the open flame below, the contoured cover 2 becomes a high-temperature radiator, emitting uniform radiant heat to the bottom of the pot body 1, which works in synergy with the convective heat exchange of the high-temperature gas in the heat exchanger 4. The high-temperature gas in the heat exchanger 4 forms natural convection due to the overall thermal buoyancy. The flue gas, after completing the uniform heat exchange at the bottom of the pot body 1 and cooling down, is discharged outward through the through holes 3 on the upper edge of the cover 2, forming a complete through-flow airflow circulation.

Claims

1. A heat equalization device for the bottom of a pot, characterized in that, It includes a contoured cover that is adapted to the outer contour of the bottom of the pot body; the contoured cover is densely covered with several through holes; the contoured cover is fixed to the outside of the bottom of the pot body and forms a semi-open heat dissipation cavity between it and the bottom of the pot body. The heat-equalizing cavity, in conjunction with the densely distributed through holes, forms a stagnant back pressure when combustion flue gas continuously enters. The stagnant back pressure, together with the flame quenching effect of the through holes, works in synergy to prevent open flame from penetrating the through holes and directly contacting the bottom of the pot. The contoured cover is heated to form a high-temperature radiator that radiates heat to the bottom of the pot, and the heat exchange chamber contains high-temperature flue gas to form convective heat exchange.

2. The pot bottom heat equalization device according to claim 1, characterized in that, The thickness of the contoured cover ranges from 0.5mm to 3.0mm, preferably from 1.0mm to 1.5mm, taking into account the flame quenching effect, thermal inertia, radiative heat transfer efficiency, weight, and structural rigidity.

3. The pot bottom heat equalization device according to claim 1, characterized in that, The aperture of the through hole ranges from 0.2mm to 8.0mm, preferably from 0.5mm to 3.0mm. This ensures the permeability of the mixture of high-temperature flue gas and incompletely burned components, enhances the flame quenching and throttling back pressure effects, and does not affect the radiative heat transfer performance of the contoured cover.

4. The pot bottom heat equalization device according to claim 1, characterized in that, For non-circular holes, the hole diameter refers to its hydraulic diameter, which is calculated using the formula: Dh = 4A / P, where A is the cross-sectional area of ​​the through hole and P is the inner circumference of the through hole.

5. The pot bottom heat equalization device according to claim 1, characterized in that, At least a portion of the through holes on the contoured cover have a diameter larger than the static critical flame quenching diameter under the corresponding working conditions. The stabilizing back pressure of the heat-spreading chamber and the flame quenching effect of the through holes work together to achieve open flame isolation.

6. The pot bottom heat equalization device according to claim 1, characterized in that, The thickness of the semi-open heat equalization cavity ranges from 0.2mm to 8.0mm, preferably from 1.0mm to 3.0mm. The thickness of the heat equalization cavity can be uniform or gradually transition to the edge of the connection between the cover and the pot body. This can buffer the impact of high-temperature flue gas flow, ensure the space for high-temperature gas convection, enhance the effect of stagnant back pressure and convective heat transfer, and enable the radiant heat of the contour cover to be efficiently transferred to the bottom of the pot.

7. The pot bottom heat equalization device according to claim 1, characterized in that, The device does not have a solid heat-conducting interlayer covering the main area of ​​the heat-equalizing cavity. Instead, it achieves uniform heating of the pot bottom by combining the flame quenching effect of the through holes in the shroud with the back pressure of the cavity to block open flame impact, flameless combustion, convection heating, surface heat radiation heating of the contoured shroud, and heat buffering of the air gap.

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