Steam cooking utensil with uniform heating function

Abstract

The invention discloses a steam cooking utensil capable of heating uniformly, a cooking cavity and a water tank are arranged in the steam cooking utensil, a heating piece used for heating water to generate steam or heating steam is convexly arranged in the water tank, and the heating piece comprises a heat transfer part and a heating part arranged in the heat transfer part; a plurality of independent heat transfer convection grooves extending in the vertical direction are formed in the surface of the heat transfer part, steam is gathered at the top end of the heat transfer part through the independent heat transfer convection grooves and enters the cooking cavity, and the width of the groove bottom of each heat transfer convection groove in the circumferential direction of the heating piece is smaller than that of a groove opening in the circumferential direction of the heating piece. According to the invention, the heat transfer convection groove is specially designed, so that the heating element has good uniformity when heating water or steam, and the application range and universality of the heating element are improved.

Description

Technical Field

[0001] The invention belongs to the field of household appliances, and in particular relates to a steam cooking device with uniform heating. Background Art

[0002] Steam cooking is one of the most common cooking methods in daily life. It can heat the food evenly and fully retain the nutrients, so it is widely used in many cooking appliances such as steam rice cookers, steamers, electric steamers, etc. Traditional steam cooking appliances are mostly composed of a cooking cavity and a water tank. The heating element heats the water in the water tank, and the steam generated by the boiling water rises into the cooking cavity to heat and steam the food placed in the cooking cavity.

[0003] There are generally two types of heating elements: one is a flat heating plate, which generally includes a heat-conducting plate arranged on the bottom wall of the water tank and a heating tube arranged below the heat-conducting plate. However, the heating tube of this heating element will be exposed to the air outside the water tank, causing part of the heat to be lost to the outside, and the energy utilization rate is relatively low; the other is a rod-shaped heating block, which generally completely wraps the heating tube into a rod-shaped heat-conducting metal. Three-dimensional heating can be achieved through the heat-conducting metal, and a scheme of opening annular grooves on the surface of the heating block has been extended to increase the heating area and improve the heating rate.

[0004] However, the inventors further studied and analyzed that the equal width design of the bottom and the groove of the annular groove is not conducive to uniform heating of the heating element. Specifically, when the heating block is used to heat water, the heat flow at the bottom of the groove and the heat flow at the groove wall easily collide to form turbulence, which hinders the outflow of hotter liquid in the groove and the inflow of colder liquid outside. In addition, the dragging effect of the boundary layer at the groove wall leads to poor fluidity inside and outside the groove and insufficient heat exchange. When the heating block is used to heat steam, this design easily hinders the flow of steam. Part of the steam will accumulate in the groove and be heated by the groove, resulting in a large difference in steam temperature inside and outside the groove, making the steam entering the cooking cavity uneven, which is not conducive to the control of steam temperature and cooking quality. There is room for further improvement. Summary of the invention

[0005] The present invention provides a steam cooking device with uniform heating to solve at least one of the above technical problems.

[0006] To achieve the above purpose, the specific technical solutions of the present invention are as follows:

[0007] A steam cooking utensil with uniform heating, wherein a cooking cavity and a water tank are provided in the steam cooking utensil, wherein a heating element for heating water to generate steam or heating steam is protrudingly provided in the water tank, wherein the heating element comprises a heat transfer portion and a heating portion arranged in the heat transfer portion, wherein a plurality of independent heat transfer convection grooves extending in the up-down direction are provided on the surface of the heat transfer portion, wherein the steam converges at the top end of the heat transfer portion through the plurality of independent heat transfer convection grooves and enters the cooking cavity, and wherein the width of the groove bottom of the heat transfer convection groove along the circumferential direction of the heating element is smaller than the width of the groove opening along the circumferential direction of the heating element.

[0008] In one embodiment of the present invention, the width of the bottom of the heat transfer convection groove along the circumference of the heating element is H1, the width of the slot opening of the heat transfer convection groove along the circumference of the heating element is H2, and H2 / H1≥1.5.

[0009] In one embodiment of the present invention, the heat transfer convection groove is a trapezoidal groove or a V-shaped groove vertically arranged along the height direction of the heating element.

[0010] In one embodiment of the present invention, a plurality of heat transfer convection grooves are arranged at intervals along the circumference of the heating element, a heat transfer protrusion is formed between two adjacent heat transfer convection grooves, and the heat generating portion is at least partially embedded in the heat transfer protrusion.

[0011] In one embodiment of the present invention, the steam cooking appliance further comprises a temperature measuring element, the heat transfer portion is provided with an installation cavity for installing the temperature measuring element, at least a portion of the installation cavity is located on the heat transfer protrusion, and the temperature measuring element and the heat generating portion are staggered along the circumferential direction of the heating element.

[0012] In one embodiment of the present invention, the water tank is provided with an exhaust hole for exhausting steam, and the top of the heat transfer part is provided with a protrusion arranged toward the exhaust hole.

[0013] In one embodiment of the present invention, the steam cooking appliance further comprises a heat-conducting cover sleeved outside the heating element, and the heat-conducting cover at least partially abuts against the heating element.

[0014] In one embodiment of the present invention, the steam cooking appliance further comprises a second heating element disposed in the water tank, the second heating element comprises a heat conducting plate and a heating tube fixedly connected to the heat conducting plate, and the heating element is disposed on the heat conducting plate.

[0015] In one embodiment of the present invention, a plurality of heat transfer convection grooves are arranged at intervals along the circumference of the heating element, a heat transfer protrusion is formed between two adjacent heat transfer convection grooves, and the heat transfer protrusions are arranged in a spiral along the circumference of the heating element.

[0016] In one embodiment of the present invention, the surface of the heat transfer part is coated with a food-grade coating or the surface of the heat transfer part is provided with a food-grade oxidation layer. After adopting the above technology, the beneficial effects of the present invention are:

[0017] The present invention provides a plurality of independent heat transfer convection grooves extending in the up-down direction on the surface of the heat transfer part, and specially designs the heat transfer convection grooves so that the width of the groove bottom of the heat transfer convection groove along the circumference of the heating element is smaller than the width of the groove opening along the circumference of the heating element. Compared with the technical solution in which the groove bottom and the groove opening have equal widths, when the heating element is used to heat water, the heat transfer convection grooves of such a shape can make the heat flows at the two groove walls staggered at a certain angle, reduce the probability of turbulence formed by collision, and avoid the turbulence driving the low-temperature liquid near the heat transfer convection groove to mix with the high-temperature liquid in the groove too early, so that the temperature difference between the inside and outside of the heat transfer convection groove is insufficient to generate a large thermal power, resulting in a problem of reduced convection intensity. At the same time, it can also reduce the obstruction and consumption of the heat flow at the groove bottom by the turbulence and the drag force of the boundary layer of the groove wall, which is convenient for the groove The heat flow at the wall flows outwards under the impetus of the heat flow at the bottom of the groove, so that even when the depth of the heat transfer convection groove is relatively large or the width of the groove is small, the water in the groove can easily flow to the external unheated area, thereby forming a three-dimensional convection in the water tank in the up and down directions, improving the convection intensity of high-temperature water bodies and low-temperature water bodies, achieving rapid and uniform heating in the water tank, and promoting the boiling of the liquid in the water tank; when the heating element is used to heat steam, the heat generated by the two groove walls of the heat transfer convection groove of such a shape is more easily radiated to the outside of the groove, avoiding the large difference in steam temperature between the inside and outside of the groove due to the concentration of heat in the groove, and will not hinder the flow of steam, so that the steam is easy to converge to the top of the heat transfer part and be further heated by the top of the heat transfer part, thereby improving the uniformity of steam heating. In this way, the heating element can have good uniformity when heating water or steam, which improves the scope of application and versatility of the heating element.

[0018] As a preferred embodiment of the present invention, the steam cooking device further comprises a heat-conducting cover sleeved outside the heating element, and the heat-conducting cover at least partially abuts against the heating element. In this way, on the one hand, the heat-conducting cover can separate a small cavity in the water tank to form a heating cavity, so that the heating element mainly heats the liquid or steam in the small cavity, further improving the heating rate; on the other hand, the heat of the heating element is fully utilized, and the heat-conducting cover absorbs and reflects the heat of the heating element, and the heat transfer area between the water or steam is increased without occupying too much volume of the water tank, and the heat-conducting cover can be used as an auxiliary heating element to perform three-dimensional multi-faceted heating of the water or steam in the heating cavity together with the heating element, thereby improving the heating efficiency; and, since the heating cavity is formed by the heat-conducting cover and the heating element, the probability of heat exchange between the steam and the relatively low external temperature air and the inner wall of the water tank during the rising process is reduced, and the loss along the way when the steam rises is reduced. At the same time, the heat-conducting cover can further heat the steam during the rising process and supplement the heat for the steam, thereby increasing the steam temperature and dryness, reducing the probability of the steam forming a condensed water film on the surface of the food, and avoiding the surface being too wet to affect the taste of the food.

[0019] These features and advantages of the present invention will be disclosed in detail in the following specific embodiments and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic structural diagram of the steam cooking appliance in one embodiment of the present invention;

[0021] Figure 2 It is a structural schematic diagram of the heating element in one embodiment of the present invention;

[0022] Figure 3 is a schematic cross-sectional structural diagram of the heating element in one embodiment of the present invention;

[0023] Figure 4 is a schematic cross-sectional structural diagram of the heating element at another angle in one embodiment of the present invention;

[0024] Figure 5 is a schematic cross-sectional structural diagram of the heating element at another angle in one embodiment of the present invention;

[0025] Figure 6 It is a structural schematic diagram of the heating element in one embodiment of the present invention;

[0026] Figure 7-1 Schematic diagram of liquid convection in slots of equal width;

[0027] Figure 7-2 A schematic diagram of liquid convection in a heat transfer convection tank according to an embodiment of the present invention;

[0028] Figure 8 The figure is a schematic structural diagram of the heating element and the heat-conducting cover in one embodiment of the present invention.

[0029] Figure numerals: cooking chamber 100; evaporation chamber 110; water replenishment chamber 120; heating chamber 130; base 200; water tank 210; flow rib 211; second heating element 220; exhaust hole 230; pot body 300; juice collecting tray 310; water barrier rib 311; steaming layer 320; heating element 400; heat transfer part 410; fixing hole 411; mounting chamber 412; protrusion 413; heating part 420; heat transfer convection groove 430; first side wall 431; second side wall 432; heat transfer protrusion 440; support block 441; mounting platform 450; water replenishment port 460; heat conductive cover 500; guide part 510; temperature measuring element 600. DETAILED DESCRIPTION

[0030] In order to better understand the purpose, structure and function of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the technical solutions and embodiments provided by the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0031] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein may be combined with each other.

[0032] refer to Figures 1 to 6 The present embodiment provides a steam cooking utensil with uniform heating, wherein the steam cooking utensil is provided with a cooking cavity 100 and a water tank 210, wherein a heating element 400 for heating water to generate steam is convexly provided in the water tank 210, wherein the heating element 400 comprises a heat transfer portion 410 and a heating portion 420 arranged in the heat transfer portion 410, wherein a plurality of independent heat transfer convection grooves 430 extending in the up-down direction are provided on the surface of the heat transfer portion 410, wherein the steam is gathered at the top of the heat transfer portion through the plurality of independent heat transfer convection grooves 430 and enters the cooking cavity 100, and the width of the groove bottom of the heat transfer convection groove 430 along the circumferential direction of the heating element is smaller than the width of the groove opening along the circumferential direction of the heating element.

[0033] For the annular groove scheme with equal width of groove bottom and groove mouth, when used for heating water, since the two groove walls are arranged opposite to each other and parallel to the flow direction of the heat flow at the groove bottom, the heat flow formed by the groove wall and the heat flow between the groove wall and the groove bottom are easy to collide to form turbulence (refer to Figure 7-1), which hinders the outflow of hotter liquid in the groove and the inflow of colder liquid outside and consumes power; when used to heat steam, the two oppositely arranged groove walls will radiate heat into the groove in a concentrated manner, resulting in a large difference in steam temperature between the inside and outside of the annular groove, which is not conducive to the control of steam temperature and cooking quality.

[0034] In this embodiment, a plurality of independent heat transfer convection grooves 430 extending in the up-down direction are provided on the surface of the heat transfer portion 410, and the heat transfer convection grooves 430 are specially designed so that the width of the groove bottom of the heat transfer convection grooves 430 along the circumference of the heating element is smaller than the width of the groove opening along the circumference of the heating element. Compared with the technical solution in which the groove bottom and the groove opening have the same width, when the heating element 400 is used to heat water, the heat transfer convection grooves 430 of such a shape can make the heat flow at the two groove walls staggered by a certain angle, reduce the probability of collision to form turbulence, and avoid turbulence. The flow drives the low-temperature liquid near the heat transfer convection groove 430 to mix with the high-temperature liquid in the groove too early, so that the temperature difference between the inside and outside of the heat transfer convection groove 430 is insufficient to generate a large thermal power, resulting in a problem of reduced convection intensity. At the same time, it can also reduce the turbulence and the drag force of the boundary layer of the groove wall on the heat flow at the bottom of the groove. It is convenient for the heat flow at the groove wall to flow outward under the impetus of the heat flow at the bottom of the groove, so that even if the depth of the heat transfer convection groove 430 is relatively large or the groove width is small, the water in the groove can easily flow to the external unheated area (refer to Figure 7-2 ), thereby forming vertical three-dimensional convection in the water tank, increasing the convection intensity of high-temperature water and low-temperature water, achieving rapid and uniform heating in the water tank, and promoting the boiling of the liquid in the water tank; when the heating element is used to heat steam, the heat transfer convection groove 430 of such a shape makes it easier for the heat generated by the two groove walls to radiate outside the groove, avoiding the large difference in steam temperature between the groove and outside the groove due to the concentration of heat in the groove, while not hindering the flow of steam, making it easier for steam to converge to the top of the heat transfer part 410 and be further heated by the top of the heat transfer part 410, thereby improving the uniformity of steam heating. In this way, the heating element 400 can have good uniformity when heating water or steam, which improves the application range and versatility of the heating element.

[0035] Preferably, the height of the heating element 400 is higher than the height of the maximum water level in the water tank, the heating portion 420 is a ring-shaped or spiral heating tube, and the heat transfer portion 410 is an aluminum block wrapped outside the heating tube to increase the heating rate.

[0036] Furthermore, the water tank 210 is provided with an exhaust hole 230 connected to the cooking cavity 100. When in use, food is placed in the cooking cavity 100, and a proper amount of water is injected into the water tank 210. The heating element 400 heats the water in the water tank 210 and promotes the convection of water and heat through the heat transfer convection groove 430, so that the steam cooking utensil can quickly generate steam, and the steam enters the cooking cavity 100 through the exhaust hole 230 to cook the food therein.

[0037] In some embodiments of the present invention, reference Figure 1 The steam cooking appliance further includes a partition, which surrounds the outer side of the heating element 400 to divide the water tank 210 into an evaporation chamber 110 and a water replenishment chamber 120. The heating element 400 is located in the evaporation chamber 110, so that the heating element 400 can concentrate on heating a small portion of water in the evaporation chamber 110, so that the water can boil in a short time to generate steam, thereby improving the steam generation rate and cooking efficiency.

[0038] It should be noted that the present invention does not specifically limit the form of the partition. For example, in a specific embodiment, the partition is a rib provided on the bottom wall of the water tank, and the height of the rib is higher than the liquid level of the water tank; in another specific embodiment, the partition is a partition cover provided outside the heating element 400, a positioning protrusion is provided at the bottom of the water tank, the heating element 400 is arranged on the positioning protrusion, and the partition cover is sleeved on the positioning protrusion and is detachably connected to the water tank 210 to facilitate user disassembly and cleaning.

[0039] In a preferred embodiment, referring to Figure 1 The steam cooking utensil is a cooking utensil such as an electric steamer, comprising a base 200 and a pot body 300 arranged on the base 200, a water tank 210 arranged on the base 200, and the pot body 300 is provided with a juice receiving tray 310. The partition is a water barrier 311 extending downward from the bottom of the juice receiving tray 310, and the bottom end of the water barrier 311 extends to the bottom of the water tank 210 so that the water barrier 311 is inserted into the water, and an evaporation chamber 110 is enclosed between the juice receiving tray 310 and the water tank 210; the pot body 300 is provided with at least one steaming layer 320, and a cooking cavity 100 for placing food is formed in the steaming layer 320.

[0040] Furthermore, the inner wall of the water tank 210 is provided with a bypass rib 211, which is arranged on the outside or inside of the water-isolating rib 311, thereby further forming a buffer zone in the evaporation chamber 110 or the water-making chamber 120, so that the colder water in the water-making chamber 120 cannot directly enter the evaporation chamber 110, thereby avoiding direct mixing with the hotter water in the evaporation chamber and causing the water temperature to drop, thereby ensuring the temperature in the evaporation chamber, allowing the water in the heating area to boil and generate steam in a short time, thereby improving the steam generation rate and cooking efficiency.

[0041] Further, refer to Figure 1 The bottom central area of ​​the juice receiving tray 310 is provided with a protrusion that rises upward to form an escape space at the lower side of the juice receiving tray, and the top of the heating element 400 extends into the escape space. This arrangement allows the heating element 400 to be arranged in a form with a longer height, thereby increasing the heat exchange amount and improving the effect of the heating element 400 on heating water and steam.

[0042] It should be noted that the above embodiment is described using an electric steam cooker as the steam cooking utensil. It can be understood that the steam cooking utensil in the embodiment of the present invention can be any cooking utensil that can use steam for cooking or auxiliary heating, such as an air fryer, an electric stew pot, a steam oven, etc., and is not limited here.

[0043] In some embodiments of the present invention, the steam cooking appliance also includes a water-proof cover and a second heating element. The water-proof cover is mounted outside the heating element 400, dividing the water tank into an evaporation chamber located outside the water-proof cover and an overheating chamber located inside the water-proof cover. The second heating element is used to heat the water in the evaporation chamber to generate steam. After the steam enters the overheating chamber through the air inlet hole set on the water-proof cover, the heating element 400 heats it to form superheated steam. The superheated steam is used to heat the food in the cooking chamber 100 to achieve the effect of high-temperature rapid steaming.

[0044] In some embodiments of the present invention, the width of the bottom of the heat transfer convection groove 430 along the circumference of the heating element is H1, and the width of the notch of the heat transfer convection groove 430 along the circumference of the heating element is H2, and H2 / H1≥1.5. Such a setting can avoid the heat transfer convection groove 430 from the groove bottom to the notch The size of the expansion is small, resulting in a certain amount of turbulence in the heat transfer convection groove 430, thereby allowing the water in the groove to easily flow to the external unheated area, thereby improving the convection effect of high-temperature water and low-temperature water. In addition, such a setting can also ensure that the heat generated by the two groove walls radiates outward from the groove, thereby improving the uniformity of steam heating.

[0045] Preferably, H1 / H2≥2, for example 2, 2.3, 2.5, 3, 3.5, 4, etc., so as to facilitate the flow of water and steam in the heat transfer convection groove 430 while allowing the water and steam near the heat transfer convection groove 430 to flow into the heat transfer convection groove 430 through the groove wall, thereby achieving rapid and uniform heating and improving heating efficiency.

[0046] Optionally, the depth of the heat transfer convection groove 430 is not greater than 1 / 2 of the radius of the heating element 400, so as to reduce the obstruction and consumption of the heat flow at the bottom of the groove by the turbulence and the drag force of the boundary layer of the groove wall, and avoid the difficulty of the heat flow in the groove to flow outward due to the excessive depth of the heat transfer convection groove 430. At the same time, it can also ensure that the heat transfer part 410 wraps the heating part 420 well, and avoid the safety hazard caused by the heat transfer part 410 being too thin at the heat transfer convection groove 430.

[0047] Furthermore, the ratio of the width of the heat transfer convection groove 430 along the circumference of the heating element to the circumference of the heating element is not greater than 0.3, so that a reasonable number of heat transfer convection grooves 430 are opened around the heating element 400 to promote uniform convection of water in the water tank.

[0048] In some embodiments of the present invention, reference Figure 2 , Figure 5 and Figure 6 The heat transfer convection groove 430 is a trapezoidal groove or a V-shaped groove vertically arranged along the height direction of the heating element 400, so as to effectively form convection in the vertical direction, improve the convection intensity of the water body, and at the same time reduce the obstruction of the steam flow, so as to facilitate the steam to converge to the top of the heat transfer part.

[0049] It should be noted that the trapezoidal groove refers to a heat transfer convection groove with a certain width at the bottom of the groove, which can be an inverted trapezoid, or a W-shape or other shape in which the bottom side is shorter than the top side; the V-shaped groove refers to a heat transfer convection groove with a smaller groove bottom width, which can be an inverted triangular groove, or an arc groove, etc.

[0050] Preferably, the heat transfer convection groove 430 is an inverted trapezoidal groove to facilitate its processing and manufacturing, reduce cleaning dead corners, and facilitate daily maintenance by users.

[0051] In some embodiments of the present invention, reference Figures 2 to 5 The heat transfer convection grooves 430 are arranged at intervals along the circumference of the heating element 400, and a heat transfer protrusion 440 is formed between two adjacent heat transfer convection grooves 430. The heating portion 420 is at least partially embedded in the heat transfer protrusion 440. The partial embedding means that at least part of the periphery of the heating portion 420 is wrapped by the heat transfer protrusion 440, that is, the maximum distance from the periphery of the heating portion 420 to the center of the heating element 400 is greater than the distance from the root of the heat transfer protrusion 440 to the center of the heating element 400.

[0052] Specifically, the heating portion 420 includes a heating section bent into a spiral or ring shape and wiring sections extending downward from both ends of the heating section, and the wiring sections are embedded in the heat transfer protrusion 440 (refer to Figure 3 and Figure 5 ). Of course, part of the heating section may also be embedded in the heat transfer protrusion 440, which is not limited here.

[0053] Such an arrangement makes the heating part 420 closer to the outer surface of the heat transfer convection groove 430 and the heat transfer protrusion 440, which is more conducive to transferring the heat of the heating part 420 to the heat transfer convection groove 430, and then quickly forming a temperature gradient between the inside of the heat transfer convection groove 430 and the unheated part outside the groove, thereby promoting water convection. In addition, compared with placing the heating part 420 in correspondence with the heat transfer convection groove 430, this can ensure that the heat transfer part 410 can wrap the heating part 420 well, and the volume of the heat transfer part 410 can be appropriately reduced. This saves costs while also ensuring the water storage capacity of the water tank, thereby extending the time that the steam cooking appliance can continuously generate steam.

[0054] For further reference, Figure 4 and Figure 5 The steam cooking appliance further includes a temperature measuring element 600, the heat transfer portion 410 is provided with an installation cavity 412 for installing the temperature measuring element 600, at least a portion of the installation cavity 412 is located on the heat transfer protrusion 440, and the temperature measuring element 600 and the heating portion 420 are staggered along the circumference of the heating element 400.

[0055] In this way, under the same volume, compared with the heat transfer part with a cylindrical or spherical surface, the temperature measuring part 600 is slightly farther away from the heating part 420 after extending into the installation cavity 412. Therefore, by increasing the distance between the temperature measuring part 600 and the heating part 420, the temperature at the location of the temperature measuring part 600 is reduced, so that the temperature measuring part 600 can work in a safe temperature environment, thereby increasing the service life of the temperature measuring part 600 without occupying too much water tank space due to increasing the volume of the heat transfer part 410. This solves the problem that when the heat transfer part 410 has a small volume, the temperature measuring part 600 needs to contact the high-temperature heating part for temperature measurement but cannot withstand high temperatures for a long time. In addition, compared with the method in which the temperature measuring part 600 is arranged outside the heat transfer part 410, such an arrangement of the temperature measuring part 600 is more sensitive, reduces the interference of the outside world on the temperature measuring part 600, and thus ensures the detection sensitivity and accuracy of the temperature measuring part 600.

[0056] Further, refer to Figure 3 , Figure 4 and Figure 5 At least one heat transfer protrusion 440 is provided with a fixing hole 411, and a fastener is inserted into the fixing hole 411 to fix the heating element 400 to the water tank 210. In this way, the fastener can be closer to the outside of the heating element 400, thereby improving the assembly stability of the heating element 400 and the water tank 210.

[0057] Preferably, the fastener is a screw, and the screw rod of the screw passes through the water tank 210 and extends into the fixing hole 411 to achieve a fixed connection between the heating element 400 and the water tank 210. Of course, the heating element 400 can also be fixed to the water tank 210 in other ways, such as snap-fitting, magnetic fixing, etc.

[0058] In some embodiments of the present invention, reference Figure 1 , Figure 3 and Figure 4 The water tank 210 is provided with an exhaust hole 230 for exhausting steam, and the top of the heat transfer part 410 is provided with a protrusion 413 arranged toward the exhaust hole 230. Such a configuration facilitates the heating element 400 to further heat the steam gathered at the top of the heat transfer part through the protrusion 413, and also allows the steam to approach the protrusion 413 and be heated by contact with the protrusion 413 when flowing toward the exhaust hole 230, thereby increasing the temperature of the steam, reducing the humidity of the steam, and reducing the probability of the steam forming a condensed water film on the surface of the food, thereby preventing the surface from being too wet and affecting the taste of the food.

[0059] In some embodiments of the present invention, reference Figure 8 The steam cooking appliance further includes a heat-conducting cover 500 sleeved outside the heating element 400 , and the heat-conducting cover 500 at least partially abuts against the heating element 400 .

[0060] In order to increase the steam generation rate, the prior art has produced a solution of increasing the heating power of the heating element and increasing the volume of the heating element to improve its heat transfer capacity, but this will cause the water tank volume to be excessively occupied, reducing the time for the cooking appliance to continuously output steam.

[0061] On the one hand, the present embodiment enables the heat-conducting cover 500 to separate a small cavity in the water tank to form a heating cavity 130, so that the heating element 400 mainly heats the liquid or steam in the small cavity, further improving the heating rate; on the other hand, the heat of the heating element 400 is fully utilized. The heat-conducting cover 500 absorbs and reflects the heat of the heating element, and the heat transfer area between the water or steam is increased without occupying too much volume of the water tank, and the heat-conducting cover can be used as an auxiliary heating element to perform three-dimensional multi-faceted heating of the water or steam in the heating cavity 130 together with the heating element 400, thereby improving the steam generation rate; and, since the heating cavity 130 is formed by the heat-conducting cover 500 and the heating element 400, the probability of heat exchange between the steam and the relatively low external temperature air and the inner wall of the water tank during the rising process is reduced, and the loss along the way when the steam rises is reduced. At the same time, the heat-conducting cover 500 can also further heat the steam during the rising process and supplement the heat for the steam, thereby increasing the steam temperature and dryness, reducing the probability of the steam forming a condensed water film on the surface of the food, and avoiding the surface being too wet to affect the taste of the food.

[0062] Preferably, the heat conductive cover 500 is made of metal with good thermal conductivity such as aluminum or stainless steel. Of course, it can also be other materials with thermal conductivity, which is not limited here.

[0063] The present invention does not specifically limit the abutment method of the heat conductive cover 500 and the heating element 400. For example, in a specific embodiment, refer to Figure 2 and Figure 8 , a heat transfer protrusion 440 is formed between two adjacent heat transfer convection grooves 430, and a support block 441 is extended outward from the bottom of the heat transfer protrusion 440, and the bottom of the heat conductive cover 500 abuts against the support block 441, and a water replenishment port 460 connected to the heating chamber 130 is formed between the heat conductive cover 500 and the support block 441; in another specific embodiment, a heat transfer protrusion 440 is formed between two adjacent heat transfer convection grooves 430, and the inner wall of the heat conductive cover 500 abuts against the outer periphery of the heat transfer protrusion 440; in another specific embodiment, reference Figure 2 The bottom of the heating element 400 extends outward to form a mounting platform 450, the bottom of the heat-conducting cover 500 abuts against the upper surface of the mounting platform 450, and the bottom of the heat-conducting cover 500 is provided with a water supply port connected to the heating chamber.

[0064] Furthermore, the top of the heat-conducting cover 500 has a guide portion 510 extending inwardly, and the guide portion 510 forms a steam outlet of the heating chamber 130 , and the steam outlet is arranged corresponding to the exhaust hole 230 .

[0065] The guide portion 510 can provide orderly guidance for the steam to flow out of the heating cavity 130, and prolong the flow path of the steam and the contact time between the steam and the heat conductive cover 500, while also making the steam outlet area smaller, which is beneficial to increasing the steam exhaust speed, allowing the steam to efficiently flow into the cooking cavity 100, thereby ensuring the efficiency of steam cooking.

[0066] In some embodiments of the present invention, reference Figure 3 and Figure 4 The steam cooking appliance further comprises a second heating element 220 disposed in the water tank 210, wherein the second heating element 220 comprises a heat conducting plate and a heating tube fixedly connected to the heat conducting plate, and the heating element 400 is disposed on the heat conducting plate.

[0067] Such a composite structure allows the following to be formed inside the water tank from the outside to the inside: a cold zone at the outermost periphery of the water tank, a hot zone near the heating tube, a cold zone between the heating tube and the heating element 400, and a hot zone near the heating element 400, thereby forming multiple pairs of convection circulation areas in the water tank, increasing the convection intensity, and further increasing the heat exchange area, promoting the boiling of the liquid in the water tank, and improving the overall heating efficiency of the cooking appliance and the steam generation rate.

[0068] Preferably, the diameter of the heating tube is not less than twice the diameter of the heating element 400 .

[0069] Optionally, the heating element 400 and the second heating element 220 may heat alternately, together, or intermittently, which is not specifically limited herein. For example, in the early stage of cooking, the heating element 400 and the second heating element 220 are heated together to quickly increase the temperature of the water body, and after steam begins to be generated in the water tank, the heating element 400 alone is used for heating.

[0070] In some embodiments of the present invention, reference Figure 6 A plurality of heat transfer convection grooves 430 are arranged at intervals along the circumference of the heating element 400 , and a heat transfer protrusion 440 is formed between two adjacent heat transfer convection grooves 430 . The heat transfer protrusion 440 is arranged in a spiral along the circumference of the heating element.

[0071] The spirally arranged heat transfer protrusions 440 can well guide the heat flow out of the heat transfer convection groove 430, so as to facilitate the orderly diffusion of the heat flow in the water tank to areas farther away from the heating area to exchange heat with cold water, thereby improving the effects of convection and heat exchange.

[0072] More specifically, the heat transfer convection groove 430 has a first side wall 431 and a second side wall 432 that are oppositely disposed, and the length of the first side wall 431 is smaller than the length of the second side wall 432 to facilitate the formation of a spiral heat flow.

[0073] In some embodiments of the present invention, the surface of the heat transfer part 410 is coated with a food-grade coating or the surface of the heat transfer part 410 is provided with a food-grade oxidation layer.

[0074] This not only improves the safety of the steam cooking appliance, but also avoids corrosion damage to the heating element 400 caused by steam, thereby increasing the service life of the heating element 400. It also makes the heating element 400 easier to maintain. The user only needs to rinse it with water or simply wipe the surface of the heat transfer part 410 when it needs to be cleaned, thereby improving the user experience.

[0075] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A steam cooking appliance with uniform heating, wherein the steam cooking appliance is provided with a cooking cavity and a water tank, wherein a heating element for heating water to generate steam or heating steam is protruding from the water tank, wherein: The heating element includes a heat transfer portion and a heating portion arranged in the heat transfer portion. The surface of the heat transfer portion is provided with a plurality of independent heat transfer convection grooves extending in the up-down direction. Steam converges at the top of the heat transfer portion through the plurality of independent heat transfer convection grooves and enters the cooking cavity. The width of the bottom of the heat transfer convection groove along the circumference of the heating element is smaller than the width of the groove opening along the circumference of the heating element.

2. The uniformly heated steam cooking device according to claim 1, characterized in that: The width of the bottom of the heat transfer convection groove along the circumferential direction of the heating element is H1, and the width of the slot opening of the heat transfer convection groove along the circumferential direction of the heating element is H2, and H2 / H1≥1.

5.

3. The uniformly heated steam cooking device according to claim 1, characterized in that: The heat transfer convection groove is a trapezoidal groove or a V-shaped groove vertically arranged along the height direction of the heating element.

4. The uniformly heated steam cooking device according to claim 1, characterized in that: A plurality of heat transfer convection grooves are arranged at intervals along the circumference of the heating element, a heat transfer protrusion is formed between two adjacent heat transfer convection grooves, and the heat generating portion is at least partially embedded in the heat transfer protrusion.

5. The uniformly heated steam cooking device according to claim 4, characterized in that: The steam cooking appliance further comprises a temperature measuring element, the heat transfer portion is provided with an installation cavity for installing the temperature measuring element, at least a portion of the installation cavity is located on the heat transfer protrusion, and the temperature measuring element and the heat generating portion are staggered along the circumferential direction of the heating element.

6. The uniformly heated steam cooking device according to claim 1, characterized in that: The water tank is provided with an exhaust hole for exhausting steam, and the top of the heat transfer part is provided with a protrusion arranged toward the exhaust hole.

7. The uniformly heated steam cooking device according to claim 1, characterized in that: The steam cooking appliance further comprises a heat-conducting cover sleeved outside the heating element, and the heat-conducting cover at least partially abuts against the heating element.

8. The uniformly heated steam cooking device according to claim 1, characterized in that: The steam cooking appliance further comprises a second heating element arranged in the water tank, wherein the second heating element comprises a heat conducting plate and a heating pipe fixedly connected to the heat conducting plate, and the heating element is arranged on the heat conducting plate.

9. The uniformly heated steam cooking device according to claim 1, characterized in that: A plurality of heat transfer convection grooves are arranged at intervals along the circumference of the heating element, and a heat transfer protrusion is formed between two adjacent heat transfer convection grooves. The heat transfer protrusions are arranged in a spiral along the circumference of the heating element.

10. The uniformly heated steam cooking device according to claim 1, characterized in that: The surface of the heat transfer part is coated with a food-grade coating or the surface of the heat transfer part is provided with a food-grade oxidation layer.

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