Fluid heater

Abstract

A fluid heater according to an embodiment of the present invention comprises: a heating plate; heating elements disposed in a plurality of rows on one surface of the heating plate; and electrodes which are disposed on one surface of the heating plate and each of which is connected to the heating element disposed at either side, wherein at least one portion of the heating elements may have a different width from the others by redistributing the load applied to the heating elements.

Description

Fluid heating heater

[0001] The present invention relates to a fluid heating heater, and more particularly, to a fluid heating heater for heating a fluid such as coolant circulating inside a vehicle.

[0002] With the trend toward environmentally friendly industrial development and the development of energy sources that replace fossil fuels, the most notable areas in the automotive industry today are electric vehicles, hybrid vehicles, and fuel cell vehicles. However, unlike vehicles powered by conventional petroleum-fired engines, these vehicles either cannot or are difficult to utilize cooling water-based heating systems.

[0003] In other words, vehicles powered by conventional petroleum-powered engines generate significant amounts of heat. Coolant circulation systems are typically installed to cool these engines, and the heat absorbed by the coolant is used to heat the interior. However, electric vehicles, hybrid vehicles, and fuel cell vehicles do not generate as much heat as engines, limiting the utility of these conventional heating methods.

[0004] Accordingly, various studies are being conducted on electric vehicles, hybrid vehicles, and fuel cell vehicles, including adding heat pumps to the air conditioning system to allow them to serve as heat sources, or installing separate heat sources such as electric heaters. Electric heaters are currently widely used, as they can heat coolant more easily and without significantly impacting the air conditioning system.

[0005] The heating elements in fluid heaters are manufactured with a constant width, generating a uniform load per unit area and generating heat with the same energy density. The thermal energy generated by the heating elements in fluid heaters is transferred to the fluid through the heating plate. However, the central area, where the heating elements are distributed, accumulates heat, resulting in a higher temperature than the periphery. This temperature increase shortens the life of the heating elements, necessitating the development of technologies that can appropriately distribute the load and achieve a uniform temperature distribution.

[0006] One embodiment of the present invention provides a fluid heating heater in which the temperature distribution of the heating elements arranged in each row becomes uniform by adjusting the width, thickness and resistivity of a heating element arranged in a central portion having a relatively high temperature among heating elements arranged in series on a heating plate to lower the load (reduce the resistance), and by adjusting the width, thickness and resistivity of the heating elements arranged in both portions to increase the load, thereby increasing the lifespan of the heating elements.

[0007] The problems to be solved by the present invention are not limited to the problems mentioned above, and other problems not mentioned herein will be clearly understood by those skilled in the art from the description below.

[0008] A fluid heating heater according to one embodiment of the present invention comprises: a heating plate; heating elements arranged in a plurality of rows on one surface of the heating plate and connected in series; and electrodes arranged on one surface of the heating plate and respectively connected to the heating elements arranged on both sides, wherein the widths of the heating elements can be formed so that at least some of them are different from each other by redistributing a load applied to the heating elements.

[0009] The width of the above heating element can be set by applying power (load) to the heating element, measuring the temperature of each heating element, and then redistributing the load.

[0010] The width (w′) of the above heating element can be calculated by substituting the redistribution coefficient (Ci) calculated by [Mathematical Formula 1] below into [Mathematical Formula 2] below.

[0011] [Mathematical Formula 1]

[0012] (Pt: initial total load applied, Ti: temperature of the ith heating element before load redistribution, k: correction factor, n: number of heating elements)

[0013] [Equation 2]

[0014] (w′: width of the heating element after load redistribution, w: width of the heating element before load redistribution, Ci: redistribution coefficient of the ith heating element)

[0015] The above correction coefficient k may be 1≤k≤2.

[0016] The above correction factor k may be 1.5.

[0017] The above heating element may be formed such that the width becomes smaller as it goes from the heating element positioned in the central portion to the heating elements positioned on both sides.

[0018] Among the above heating elements, at least one heating element having a width smaller than the heating element that is the reference is arranged on one side of the heating element (center portion) that is the reference, and on the other side, the heating element can be formed to have a width that is equal to or smaller than the width of the heating element that is the reference as it gets farther away from the heating element that is the reference.

[0019] The above heating element may be formed so that the width becomes smaller from the heating element placed on one side to the heating element placed on the other side.

[0020] The above heating element may be connected in series in multiple numbers through the electrodes on one surface of the above heating plate.

[0021] The above heating element forms a single heating element unit in which a plurality of heating elements are connected in series on one surface of the heating plate, and the heating element units can be connected in parallel through the electrodes.

[0022] The above electrodes can be connected to the ends of the heating elements arranged on both sides of the heating elements.

[0023] According to one embodiment of the present invention, by adjusting the width, thickness and resistivity of a heating element arranged in a central portion with a relatively high temperature among heating elements arranged in series on a heating plate, the load is lowered (the resistance is reduced), and by adjusting the width, thickness and resistivity of heating elements arranged on both sides, the load is increased, so that the temperature distribution of the heating elements arranged in each row becomes uniform, and thus the lifespan of the heating elements can be increased.

[0024] FIG. 1 is a perspective view illustrating a fluid heating heater according to one embodiment of the present invention.

[0025] FIG. 2 is a plan view illustrating a heating element structure of a fluid heating heater according to one embodiment of the present invention.

[0026] FIG. 3a is a drawing exemplarily showing a heating element structure of a fluid heating heater according to one embodiment of the present invention connected in series.

[0027] FIG. 3b is a drawing exemplarily showing a heating element structure of a fluid heating heater according to one embodiment of the present invention connected in series.

[0028] FIG. 4 is a drawing comparing the heat generation density and temperature distribution of a heating element structure of a fluid heating heater according to one embodiment of the present invention and a conventional heating element structure.

[0029] FIG. 5 is a drawing showing the heating element structure of a fluid heating heater according to another embodiment of the present invention.

[0030] FIG. 6 is a drawing showing the heating element structure of a fluid heating heater according to another embodiment of the present invention.

[0031] Figure 7 is a drawing illustrating redistribution of the load of a heating element by changing the width of the heating element.

[0032] Figure 8 is a graph comparing the change in the width of the heating element according to the correction factor k when the width of the heating element is changed.

[0033] Figure 9 is a diagram showing the temperature distribution of a heating element according to the correction factor k when the width of the heating element is changed.

[0034] Fig. 10 is a cross-sectional view showing the heating element structure of a fluid heating heater according to another embodiment of the present invention.

[0035] FIG. 11 is a drawing comparing the heat generation density and temperature distribution of a heating element structure of a fluid heating heater according to another embodiment of the present invention and a conventional heating element structure.

[0036] Figure 12 is a drawing showing various examples according to the size of the heat generation density in the heating element structure.

[0037] Figure 13 is a drawing illustrating redistribution of load by changing the thickness of a heating element.

[0038] Figure 14 is a diagram illustrating redistribution of load by changing the resistivity of a heating element.

[0039] Figure 15 is a graph showing the temperature characteristics of a heating element according to the correction factor k when the thickness and resistivity of the heating element are changed.

[0040] Figure 16 is a diagram showing the temperature distribution of a heating element according to the correction coefficient k when the thickness and resistivity of the heating element are changed.

[0041] Figure 17 is a drawing illustrating redistribution of the load of a heating element.

[0042] The present invention is susceptible to various modifications and embodiments, and specific embodiments are illustrated and described in detail in the drawings. However, this is not intended to limit the present invention to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention. In describing the present invention, detailed descriptions of related known technologies will be omitted if they are deemed to obscure the gist of the present invention.

[0043] Terms such as first, second, etc. may be used to describe various components, but these components should not be limited by these terms. These terms are used solely to distinguish one component from another.

[0044] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the terms "comprises" or "has" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0045] Additionally, throughout the specification, when we say "connected," this does not only mean that two or more components are directly connected, but also that two or more components are indirectly connected through other components, that they are electrically connected as well as physically connected, or that they are referred to by different names depending on location or function but are one.

[0046] Hereinafter, one embodiment of a fluid heating heater according to the present invention will be described in detail with reference to the attached drawings. In describing with reference to the attached drawings, identical or corresponding components are assigned the same drawing numbers and redundant descriptions thereof will be omitted.

[0047] FIG. 1 is a perspective view illustrating a fluid heating heater according to an embodiment of the present invention, FIG. 2 is a plan view illustrating a heating element structure of a fluid heating heater according to an embodiment of the present invention, FIG. 3a is a drawing exemplarily illustrating a heating element structure of a fluid heating heater according to an embodiment of the present invention in which the heating element structure is connected in series, FIG. 3b is a drawing exemplarily illustrating a heating element structure of a fluid heating heater according to an embodiment of the present invention in which the heating element structure is connected in series, and FIG. 4 is a drawing comparing the heating density and temperature distribution of a heating element structure of a fluid heating heater according to an embodiment of the present invention and a conventional heating element structure.

[0048] As shown therein, a fluid heating heater according to one embodiment of the present invention includes a heating plate (10), a plurality of heating elements (30) arranged in rows on one surface of the heating plate (10), and electrodes (20) arranged on one surface of the heating plate (10) and respectively connected to the heating elements (30) arranged on both sides, and the widths of the heating elements (30) can be formed so that at least a portion thereof is different from each other by redistributing the load applied to the heating elements (30).

[0049] The fluid heating heater may be, for example, a thick film heater. The thick film heater is a plate-shaped heating element that is manufactured by printing a high-functional heating element on various substrates (such as iron plates, glass, ceramics, etc.) using a printing technique to maximize thinness and lightness and thermal efficiency. It is mainly used for industrial purposes (e.g., hot presses, diesel car fuel preheaters, wafer preheating heaters, etc.), household purposes (e.g., hair straighteners, small humidifiers, thermal skin massage heaters, heating, cook tops, etc.), and medical purposes (e.g., local heating devices, skin treatment heaters). In the present embodiment, it can be used as a fluid heating heater.

[0050] The heating plate (10) is formed in a roughly rectangular shape, and can be heated by moving a fluid such as a coolant along one surface. A plurality of heating elements (30) can be arranged in rows on one surface of the heating plate (10). The heating elements (30) can be connected in series or in parallel, and each end can be connected via an electrode (20). In other words, the heating elements (30) can be arranged in a plurality of rows in parallel in both directions on one surface of the heating plate (10).

[0051] When current flows through the heating element (30) arranged in this manner, heat is generated, and the temperature of the central portion (on both sides) where the heating elements (30) are concentratedly distributed becomes relatively high, and the temperature of the outer portions (on both sides) becomes relatively low. If the temperature distribution of the heating element (30) is not uniform along both directions, the lifespan of the heating element (30) that generates relatively high heat is shortened, so it is necessary to appropriately redistribute the load applied to the heating element (30) to make the temperature distribution uniform.

[0052] Accordingly, in this embodiment, the width of each heating element (30) is changed in order to control the load applied to the heating element (30) arranged in each row. That is, among the heating elements (30) arranged in multiple rows, the width of the heating element (30) arranged in the central portion where the temperature is relatively high is made larger to lower the load (reduce the resistance), and the width of the heating elements (30) arranged on both sides is made smaller to increase the load. When the heating elements (30) are arranged in this way, the temperature distribution of the heating elements (30) arranged in each row along both sides becomes uniform, so that the lifespan of the heating elements (30) can be increased.

[0053] Referring to Fig. 2, among the heating elements (30), the heating element (30) arranged in the central portion may have the largest width and the widths of the heating elements (30) may become smaller as they go toward the two sides. At this time, the heating elements (30) may be grouped into a set in groups of several to form the width as they go from the central portion to the two sides. For example, the widths of the two heating elements (30) arranged in the central portion may be set to be the largest, and the widths of the two heating elements (30) arranged immediately on either side may be set to be slightly smaller.

[0054] Referring to Fig. 3a, it illustrates that heating elements (30) are connected in series. A plurality of heating elements (30) may be arranged, for example, from left to right, and the upper and lower ends may be connected in series to the electrodes (20). When current flows through the heating elements (30) in this series-connected state, heat is generated. The temperature of the central portion (on both sides) where the heating elements (30) are concentrated is relatively high, and the temperature of the outer portions (on both sides) is relatively low. Therefore, the width of each heating element (30) may be changed in order to appropriately redistribute the load applied to the heating elements (30) to make the temperature distribution uniform.

[0055] Referring to Fig. 3b, it illustrates that heating elements (30) are connected in parallel. A plurality of heating elements (30) may be arranged, for example, from left to right, and some may form a single unit in which the upper and lower portions are connected in series to the electrodes (20). In this way, a single heating element (30) unit connected in series can form a parallel structure by allowing current to flow to the portions of the electrodes (20) that are connected to each other.

[0056] When current flows through the heating element (30) in a parallel connection state like this, heat is generated, and the temperature of the central portion (on both sides) where the heating element (30) units are concentrated becomes relatively high, and the temperature of the outer portions (on both sides) becomes relatively low. Therefore, in order to appropriately redistribute the load applied to the heating element (30) and make the temperature distribution uniform, the width of each heating element (30) can be changed.

[0057] Referring to Fig. 4, a comparison is made between (a) the existing heating element (30) having the same width and (b) the present embodiment in which the heating element (30) has different widths in both directions.

[0058] As can be easily seen from the drawing, in the past, the temperature was high in the heating element (30) positioned in the central portion, but in this embodiment, the temperature of the heating element (30) is uniformly distributed over the entire area from the central portion to both sides. In this way, in this embodiment, the overall temperature distribution of the heating element (30) can be made uniform by redistributing the load by appropriately changing the width of the heating element (30). In addition, in the case of the heating element (30) of the thick-film heater to which this embodiment is applied, it is relatively easy to change the width because it is printed through a metal mask.

[0059] FIG. 5 is a drawing showing a heating element structure of a fluid heating heater according to another embodiment of the present invention, and FIG. 6 is a drawing showing a heating element structure of a fluid heating heater according to another embodiment of the present invention.

[0060] Looking at the embodiment illustrated in FIG. 5, at least one heating element (30) having a smaller width than the heating element (30) as a reference is arranged in the central portion, and on one side, the heating element (30) can be arranged so that the width becomes equal to or smaller than the width of the heating element (30) as it gets farther away from the heating element (30) as a reference.

[0061] Looking at the embodiment illustrated in Fig. 6, the heating element (30) placed on one side can be used as a reference, and the width can be arranged to become smaller as it goes toward the other side (farther away) from the heating element (30) that serves as the reference.

[0062] The embodiments illustrated in FIGS. 5 and 6 are exemplarily presented to show that the width of the heating element (30) can be set in various ways, and the width of the heating element (30) can be set in various combinations in addition to the embodiments presented herein.

[0063] Figure 7 is a drawing illustrating redistribution of the load of a heating element by changing the width of the heating element.

[0064] Referring to Fig. 7, assuming that the total load is 20W of power, if the width of the heating elements (30) is set to 10mm as shown on the left, the load applied to each heating element (30) becomes 10W. This is a suggestion of the existing heating element (30) structure, and there is a problem that the temperature distribution of the heating element (30) is uneven.

[0065] To solve this, if the width of the heating element (30) is set differently to redistribute the load as shown on the right, that is, if the width of the heating element (30) arranged in the central portion is set to 12.5 mm and the widths of the heating elements (30) arranged on both sides are set to 8.33 mm, 8 W of the load is distributed to the heating element (30) with a large width, and 12 W is distributed to the heating element (30) with a small width. Since the load is redistributed in this way, the temperature does not rise on the side of the heating element (30) with a small load, so that the temperature distribution can be made uniform overall.

[0066] Fig. 8 is a graph showing the temperature characteristics of a heating element according to a correction factor k when the width of the heating element is changed, and Fig. 9 is a drawing comparing the change in the width of the heating element according to the correction factor k when the width of the heating element is changed.

[0067] In the above, it has been explained that the width is changed to redistribute the load applied to the heating element (30). The width of the heating element (30) is not determined arbitrarily, but must be set to a width that can optimize the overall temperature distribution.

[0068] Therefore, in this embodiment, in order to derive this, the temperature of each heating element (30) was predicted from an existing model designed with n heating elements (30) having the same width, and the width of each heating element (30) was determined so that the load proportional to the k power of the reciprocal of the temperature was the same.

[0069] To summarize,

[0070] 1) Calculate the average temperature Ta (a=1, 2, 3, ..., n) for each heating element (30) of n heating elements (30) having the same width,

[0071] 2) The load Pa (a=1, 2, 3, ..., n) of each heating element (30) is redistributed in proportion to (the total load is the same as before the width change)

[0072] 3) The width (w) of the heating element (30) so that the a-th heating element has a load of Pa a ) is set

[0073] At this time, in order to obtain the optimal value of k presented as a correction coefficient, the temperature difference for each heating element (30) was examined while changing k. As a result, it was confirmed that when the k value was 1≤k≤2, the temperature distribution was relatively uniform, and when the k value was 1.5, the temperature difference for each heating element (30) was minimized and the temperature distribution was uniform.

[0074] In other words, when the load of each heating element (30) is rearranged inversely proportional to the 1.5(k) square of the temperature of each heating element (30) in the existing heating element (30) structure with the same width, the temperature distribution is most uniform, the maximum temperature is also the lowest, and the lifespan of the heating element (30) can be expected to be the longest.

[0075] FIG. 10 is a cross-sectional view showing a heating element structure of a fluid heating heater according to another embodiment of the present invention, and FIG. 11 is a drawing comparing the heating density and temperature distribution of a heating element structure of a fluid heating heater according to another embodiment of the present invention and a conventional heating element structure.

[0076] In the above-described embodiment, the width of the heating element (30) is adjusted to redistribute the load applied to the heating element (30). In this embodiment, the thickness and resistivity of the heating element (30) are set differently to redistribute the load of the heating element (30).

[0077] A fluid heating heater according to another embodiment of the present invention includes a heating plate (10), a heating element (30) arranged in a plurality of rows on one surface of the heating plate (10), and electrodes (20) arranged on one surface of the heating plate (10) and respectively connected to the heating elements (30) arranged on both sides, and the thickness and resistivity of the heating element (30) can be formed to be at least partially different from each other by redistributing a load applied to the heating element (30).

[0078] Referring to Fig. 10, among the heating elements (30) arranged in both directions, the thickness of the heating element (30) arranged in the central portion is made large, and the thickness of the heating element (30) is formed to become smaller as it goes toward both sides. That is, as the thickness of the heating element (30) increases, the resistance decreases, so the load of the heating element (30) can be lowered.

[0079] In addition, among the heating elements (30) arranged in both directions, the resistivity of the heating element (30) arranged in the central portion is made small, and the resistivity of the heating element (30) is formed to increase as it goes toward both sides. Since the resistivity is proportional to the resistance, the resistivity is made small in order to reduce the load applied to the heating element (30). In other words, the load applied to the heating element (30) and the resistivity must be configured to be proportional.

[0080] Figure 12 is a drawing showing various examples according to the size of the heat generation density in the heating element structure.

[0081] Referring to Fig. 12, among the heating elements (30) arranged in both directions, there is at least one heating element (30) whose heat generation density (loss density) is set differently centered on a reference heating element (30) (a), and the heating element (30) that is further away from the reference heating element (30) has a heat generation density equal to or greater than that of the heating element (30) that is closer to the reference heating element (30) (b). In addition, when the reference heating element (30) is arranged on one side, it may be arranged so that the heat generation density increases toward the other side (c).

[0082] Figure 13 is a drawing illustrating redistribution of load by changing the thickness of a heating element.

[0083] Referring to Fig. 13, assuming that the total load is 20W of power, if the thickness of the heating elements (30) is set to 1mm as shown on the left, the load applied to each heating element (30) becomes 10W. This is a suggestion of the existing heating element (30) structure, and there is a problem that the temperature distribution of the heating element (30) is uneven.

[0084] To solve this, if the thickness of the heating element (30) is set differently to redistribute the load as shown on the right, that is, if the width of the heating element (30) placed in the central portion is set to 1.25 mm and the widths of the heating elements (30) placed on both sides are set to 0.833 mm, 8 W of the load is distributed to the heating element (30) with a large thickness, and 12 W is distributed to the heating element (30) with a small thickness. Since the load is redistributed in this way, the temperature does not rise on the side of the heating element (30) with a small load, so that the temperature distribution can be made uniform overall.

[0085] Figure 14 is a diagram illustrating redistribution of load by changing the resistivity of a heating element.

[0086] Referring to Fig. 14, assuming that the total load is 20W of power, if the resistivity of the heating elements (30) is set to 1 as shown on the left, the load applied to each heating element (30) becomes 10W. This is a suggestion of the existing heating element (30) structure, and there is a problem that the temperature distribution of the heating element (30) is uneven.

[0087] To solve this, if the resistivity of the heating element (30) is set differently to redistribute the load as shown on the right, that is, if the resistivity of the heating element (30) placed in the central portion is set to 0.8 and the resistivity of the heating elements (30) placed on both sides is set to 1.2, 8 W of the load is distributed to the heating element (30) with a small resistivity, and 12 W is distributed to the heating element (30) with a large resistivity. Since the load is redistributed in this way, the temperature does not rise on the side of the heating element (30) with a small load, so that the temperature distribution can be made uniform overall.

[0088] Fig. 15 is a graph showing the temperature characteristics of a heating element according to a correction factor k when the thickness and resistivity of the heating element are changed, and Fig. 16 is a diagram showing the temperature distribution of a heating element according to a correction factor k when the thickness and resistivity of the heating element are changed.

[0089] In the above, it has been explained that the thickness and resistivity are changed to redistribute the load applied to the heating element (30). The thickness and resistivity of the heating element (30) are not determined arbitrarily, but must be set so as to optimize the overall temperature distribution.

[0090] Therefore, in this embodiment, in order to derive this, the temperature of each heating element (30) was predicted from an existing model designed with n heating elements (30) having the same width, and the thickness and resistivity of each heating element (30) were determined so that the load proportional to the k power of the reciprocal of the temperature was the same.

[0091] To summarize,

[0092] 1) Calculate the average temperature Ta (a=1, 2, 3, ..., n) for each heating element (30) of n heating elements (30) having the same width, thickness, and resistivity,

[0093] 2) The load Pa (a=1, 2, 3, ..., n) of each heating element (30) is redistributed in a ratio of (the total load is the same as before the thickness and resistivity change)

[0094] 3) The thickness (t) of the heating element (30) so that the a-th heating element has a load of Pa a ) and resistivity (σ a ) is set

[0095] At this time, in order to obtain the optimal value of k presented as a correction coefficient, the temperature difference for each heating element (30) was examined while changing k. As a result, it was confirmed that when the k value was 2≤k≤3, the temperature distribution was relatively uniform, and when the k value was 2.5, the temperature difference for each heating element (30) was minimized and the temperature distribution was uniform.

[0096] In other words, when the load of each heating element (30) is rearranged so as to be inversely proportional to the 2.5(k) square of the temperature of each heating element (30) in the existing heating element (30) structure having the same thickness and resistivity, the temperature distribution is most uniform, the maximum temperature is also the lowest, and the lifespan of the heating element (30) can be expected to be the longest.

[0097] Meanwhile, the load change due to the correction factor k is different from the optimal k value of the present embodiment because, unlike the present embodiment in which the heating area does not change, the heating area changes due to the change in the width of the heating element (30) in the above-described embodiment, so that the temperature change is severe and the present embodiment has a different optimal k value. A large k means that the load difference for each heating element (30) is made larger, and since the temperature change occurs more when the width of the heating element (30) is changed, a larger temperature change can be created compared to the example in which the thickness and resistivity are changed even at a small k.

[0098] Figure 17 is a drawing illustrating redistribution of the load of a heating element.

[0099] First, 800 W of power (Pt: total load) is applied to heating elements (30) connected in series with the same width, thickness, and resistivity. At this time, the temperatures T1 to T8 of each heating element (30) are measured.

[0100] Next, in order to make the temperature distribution of the heating element (30) uniform, the redistribution coefficient (Ci) that can redistribute P1 to P8 inversely proportional to the square of the temperature k (correction coefficient) is calculated using the following [Mathematical Formula 1]. Then, the load of the ith heating element (30) after redistribution can be calculated as in the following [Mathematical Formula 2].

[0101] [Mathematical Formula 1]

[0102] (Pt: initial total load applied, Ti: temperature of the ith heating element before load redistribution, k: correction factor 1≤k≥2, n: number of heating elements)

[0103] Using the redistribution coefficient calculated in this way, the width, thickness, and resistivity of the heating element (30) before load redistribution can be calculated by [Mathematical Formula 2] to [Mathematical Formula 4] below.

[0104] [Equation 2]

[0105] (w′: width of the heating element after load redistribution, w: width of the heating element before load redistribution, Ci: redistribution coefficient of the ith heating element)

[0106] [Equation 3]

[0107] (t′: thickness of the heating element after load redistribution, w: thickness of the heating element before load redistribution, Ci: redistribution coefficient of the ith heating element)

[0108] [Equation 4]

[0109] (ρ′: resistivity of the heating element after load redistribution, ρ: resistivity of the heating element before load redistribution, Ci: redistribution coefficient of the ith heating element)

[0110] The process of deriving this is explained as follows.

[0111] That is, the load (Pi') of the heating element (30) redistributed through the redistribution coefficient is as shown in [Mathematical Formula 5] below.

[0112] [Equation 5]

[0113] (Pi′: load of the ith heating element after load redistribution, Pi: load of the ith heating element before load redistribution)

[0114] Here P=I 2 Since R is proportional to the resistance, and R is inversely proportional to the width and thickness of the heating element (30) as in [Mathematical Formula 6] and proportional to the resistivity, a redistribution coefficient is applied as in [Mathematical Formula 2] to [Mathematical Formula 4].

[0115] [Equation 6]

[0116] (R: resistance, ρ: resistivity, L: length of heating element, w: width of heating element, t: thickness of heating element)

[0117] Although the present invention has been described above with reference to specific embodiments thereof, it will be understood by those skilled in the art that various modifications and changes may be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below.

[0118] [Explanation of symbols]

[0119] 10: Heating plate 20: Electrode

[0120] 30: Heating element

Claims

1. Heating plate; A heating element arranged in multiple rows on one surface of the above heating plate; and It includes electrodes arranged on one side of the above heating plate and each connected to the heating elements arranged on both sides, A fluid heating heater in which the width of the heating element is formed at least partially differently to redistribute the load applied to the heating element.

2. In paragraph 1, A fluid heating heater in which the width of the heating element is set by applying power (load) to the heating element, measuring the temperature of each heating element, and then redistributing the load.

3. In paragraph 2, A fluid heating heater in which the width (w′) of the above heating element is calculated by substituting the redistribution coefficient (Ci) calculated by [Mathematical Formula 1] below into [Mathematical Formula 2] below. [Mathematical Formula 1] (Pt: initial total load applied, Ti: temperature of the ith heating element before load redistribution, k: correction factor, n: number of heating elements) [Equation 2] (w′: width of the heating element after load redistribution, w: width of the heating element before load redistribution, Ci: redistribution coefficient of the ith heating element) 4. In paragraph 3, A fluid heating heater in which the above correction coefficient k is 1≤k≤2.

5. In paragraph 4, A fluid heating heater with the above correction factor k being 1.

5.

6. In paragraph 1, The above heating element is a fluid heating heater in which the width becomes smaller as it goes from the heating element positioned in the central portion to the heating elements positioned on both sides.

7. In paragraph 1, A fluid heating heater in which at least one heating element having a width smaller than the reference heating element is arranged on one side of the reference heating element (center portion) among the above heating elements, and on the other side, the width is formed to be equal to or smaller than the width of the reference heating element as it gets farther away from the reference heating element.

8. In paragraph 1, The above heating element is a fluid heating heater in which the width becomes smaller from the heating element placed on one side to the heating element placed on the other side.

9. In paragraph 1, The above heating element is a fluid heating heater in which a plurality of heating elements are connected in series through the electrodes on one surface of the heating plate.

10. In paragraph 1, The above heating element forms a single heating element unit in which a plurality of heating elements are connected in series on one surface of the above heating plate, and the heating element units are connected in parallel through the electrodes.

11. In paragraph 1, The above electrodes are a fluid heating heater each connected to the ends of the above heating elements arranged on both sides of the above heating elements.

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