Ultra-thin combined frame

Abstract

The present invention discloses an ultra-thin combined collecting frame, comprising a collecting frame that can be fixedly sleeved on the outer surface around a partition made of a thermal insulation material, wherein a hollow structure is formed inside the collecting frame. The present invention improves the thermal insulation effect of the collecting frame by forming a hollow structure inside the collecting frame around the partition, and effectively reduces the condensation phenomenon of the collecting frame. Furthermore, a linear body formed by extrusion of PVC material and an L-shaped corner formed by injection are spliced ​​through a tenon structure, so the structure is simple, the assembly is convenient, the manufacturing cost is reduced, and the thermal insulation effect is improved. The thickness of the collecting frame is effectively reduced to 25 mm, which greatly saves the material usage of the collecting frame and the partition, and reduces the overall production cost of the thermal insulation board body.

Description

Technical Field

[0001] The invention relates to a heat insulation board, in particular to an ultra-thin combined frame. Background Art

[0002] At present, most of the structure of the combined air-conditioning box shell partition on the market has a thickness of 50mm. The inside and outside of the plate are metal plates, and the middle part of the plate is injected with PU foam or cotton or other thermal insulation materials. Basically, under the temperature difference conditions inside and outside the general air-conditioning box, there is little condensation on the surface of the partition plate body, and most of the condensation occurs at the joint of the frame, that is, the joint of the frame.

[0003] The frame is mainly used for the enclosure structure between the panels or corner edges of the combined air-conditioning box. The enclosure structure of the combined air-conditioning box is required to have a sufficiently large thermal resistance and maintain a certain thermal resistance during long-term use.

[0004] In order to reduce the heat transfer area of ​​the outer protective structure of the combined air conditioner, the outer shell design is required to be as close to a cubic shape as possible. This can minimize the ratio of the unit volume of the air conditioner to the area of ​​the outer protective structure.

[0005] The temperature difference design of the inner and outer layers of the combined air conditioner is most likely to transfer heat at the joints between the plates or at the outer corner frames. Therefore, the temperature difference design is an important parameter for selecting materials and joints in the design of the air conditioner shell. In addition to having a good thermal insulation effect, it also needs to have a good airtight design. When the airflow passes through the inside of the air conditioner, under the standard temperature difference between the inside and outside, the shell surface does not frost (or condense) to maintain the characteristics of the thermal insulation material.

[0006] The thermal insulation design of the combined air conditioner is mainly to prevent the temperature difference between the inside and outside from causing excessive heat inflow and outflow. In addition to the design of the refrigeration system, the same principle applies to the heating system. The thermal insulation design is the most important part of the air conditioner, so reducing the heat transfer of the outer shell enclosure structure can not only ensure that the outer layer does not condense and does not generate heat loss, but also achieve the purpose of environmental protection and energy saving.

[0007] The heat transfer of the combined air-conditioning box through the enclosure structure is proportional to the unit heat transfer of the peripheral structure. To reduce the unit heat flow of the outer shell structure, one is to select insulation materials with low thermal conductivity; the other is to increase the thickness of the insulation layer. The thickness should not be too thick, otherwise there will be problems such as increased construction costs and increased space occupied by the air-conditioning box. Therefore, the best insulation material should be selected within the appropriate thickness range. Summary of the invention

[0008] In order to overcome the above-mentioned defects, the present invention provides an ultra-thin combined collecting frame, which can effectively reduce the condensation phenomenon of the collecting frame, greatly reduce the thickness of the collecting frame, and save materials.

[0009] The technical solution adopted by the present invention to solve its technical problems is: an ultra-thin combined collecting frame, including a collecting frame that can be fixedly mounted on the outer surface of the partition made of thermal insulation material, and a hollow structure is formed inside the collecting frame.

[0010] As a further improvement of the present invention, the frame includes a straight body and an L-shaped corner, and both ends of the L-shaped corner can be fixedly spliced ​​with the end of the straight body to form an integrated structure.

[0011] As a further improvement of the present invention, the straight body and the L-shaped corner are fixedly connected via a tenon structure.

[0012] As a further improvement of the present invention, the linear body is an extruded profile, and at least one through hole is formed inside the linear body in the length direction. The through hole forms a female tenon of the tenon structure, and the side walls at both ends of the L-shaped corner are respectively provided with protruding male tenons, and the male tenon can be tightly inserted in the female tenon.

[0013] As a further improvement of the present invention, the linear body is formed with no less than three through holes arranged at intervals along the thickness direction thereof, and the middle through hole forms a female tenon.

[0014] As a further improvement of the present invention, first opening groove structures penetrating the length direction of the linear body are respectively formed on two opposite side walls of the linear body along the thickness direction of the wrist frame, and the two first opening groove structures are respectively connected to a through hole.

[0015] As a further improvement of the present invention, the L-shaped corner is provided with a second opening groove structure on the two opposite side walls along the thickness direction of the frame, and the opening of the second opening groove structure is connected with the first opening groove structure to form an annular opening channel located on the two opposite side walls in the thickness direction of the frame.

[0016] As a further improvement of the present invention, step structures are respectively formed on both side walls of the collecting frame along the thickness direction thereof, and the thickness dimension of the collecting frame on the side close to the partition is smaller than the thickness dimension on the side away from the partition.

[0017] As a further improvement of the present invention, a penetrating annular inwardly concave shallow groove structure is formed in the middle portion of the outer surface of the frame facing away from the partition.

[0018] As a further improvement of the present invention, the straight body and L-shaped corner of the frame are both integrally formed structures of PVC material.

[0019] The beneficial effects of the present invention are as follows: the present invention forms a hollow structure inside the collecting frame around the partition, thereby improving the heat insulation effect of the collecting frame and effectively reducing the condensation phenomenon of the collecting frame. Moreover, the linear main body formed by extrusion of PVC material and the L-shaped corner formed by injection are spliced ​​through a tenon structure. The structure is simple and the assembly is convenient, which reduces the manufacturing cost and improves the heat insulation effect. The thickness of the collecting frame is effectively reduced to 25mm, which greatly saves the material usage of the collecting frame and the partition, and reduces the overall production cost of the insulation board. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Heat transfer diagram for a steady-state flat wall

[0021] Figure 2 Thermal convection diagram for a steady flat wall

[0022] Figure 3 This is a composite heat transfer diagram of heat conduction and convection.

[0023] Figure 4 Typical heat radiation heat transfer diagram

[0024] Figure 5 A three-dimensional diagram of a linear body of the present invention;

[0025] Figure 6 is a cross-sectional view of a linear body of the present invention;

[0026] Figure 7 It is a three-dimensional diagram of an L-shaped corner of the present invention;

[0027] Figure 8 It is the front view of the L-shaped corner of the present invention;

[0028] Fig. 9 It is a left view of the L-shaped corner of the present invention;

[0029] Fig.10 It is a right side view of the L-shaped corner of the present invention;

[0030] Fig.11 A top view of an L-shaped corner of the present invention;

[0031] Fig.12 A bottom view of an L-shaped corner of the present invention;

[0032] Fig.13 It is a schematic diagram of the assembly state of the present invention;

[0033] Fig.14 This is the numerical simulation diagram of the temperature layer of the solid PVC frame;

[0034] Fig.15 This is a numerical simulation diagram of the temperature layer of the hollow PVC frame. DETAILED DESCRIPTION

[0035] Embodiment: An ultra-thin combined collecting frame, characterized in that it includes a collecting frame that can be fixedly mounted on the outer surface of the partition made of thermal insulation material, and a hollow structure is formed inside the collecting frame.

[0036] According to thermal engineering, there are three main methods of thermal insulation design: steam insulation layer method, air layer method and increased thermal resistance method. The specific principles are as follows:

[0037] 1. Steam insulation layer method: Several layers of thermal insulation layers are laid on the high-temperature side of the enclosure structure to isolate the steam, so as to reduce the steam entering the thermal insulation material from the high-temperature direction. However, this method can only delay the process of the thermal insulation material getting wet, and it is not easy to completely maintain its long-term thermal insulation.

[0038] 2. Air layer method: A moisture-inducing air layer is set on the low-temperature side of the thermal insulation layer of the enclosure structure of the air-conditioning box, which can cut off the heat transfer and moisture-inducing effect of the liquid water in the thermal insulation layer, thus ensuring the long-term thermal insulation of the outer enclosure structure of the air-conditioning box. In addition, in the hollow air layer, using the air layer as a moisture-inducing space and the thermal insulation layer has a very good and significant effect.

[0039] 3. Increasing thermal resistance method: Thickening the outer protective structure of the air-conditioning box increases the thermal resistance, which can reduce both the heat conduction and heat convection, and the diffusion with the heat flow will also become smaller. When a dynamic equilibrium is formed with the liquid water moving in the opposite direction, water vapor will not easily enter the enclosure structure, and a so-called vapor barrier layer will be formed on the surface layer of the outer protective structure.

[0040] The present invention is designed according to the air layer method of thermal insulation design. In addition to meeting the requirements of thermal design of the air-conditioning box shell, it also utilizes the hollow space to achieve super strong thermal insulation characteristics. Its thickness is designed to be only 25mm to have sufficient thermal resistance to meet the temperature difference between the inner and outer layers of the air-conditioning box, making it difficult for condensation to occur on the outer layer of the air-conditioning box.

[0041] The frame includes a linear body 1 and an L-shaped corner 2. Both ends of the L-shaped corner 2 can be fixedly spliced ​​with the ends of the linear body 1 to form an integrated structure. The split design facilitates processing and manufacturing, saving processing costs.

[0042] The linear body 1 and the L-shaped corner 2 are fixedly connected by a tenon structure, which makes the overall assembly or disassembly more convenient and saves considerable assembly time.

[0043] The linear body 1 is an extruded profile, and at least one through hole 11 is formed inside the linear body 1 in the length direction thereof. The through hole 11 forms a female tenon of the tenon structure. The side walls at both ends of the L-shaped corner 2 are respectively provided with protruding male tenons 21, and the male tenons 21 can be tightly inserted into the female tenons. The linear body 1 is processed and manufactured by extruding the profile, and the processing efficiency is high. The linear body 1 can be up to more than 6m in length and can be cut according to actual needs. The through hole formed in the extruded profile is used to form a hollow structure of the frame, and can also be used as a female tenon of the tenon structure, with one structure having two functions.

[0044] The linear body 1 is provided with at least three through holes 11 arranged at intervals along the thickness direction thereof, and the middle through hole 11 forms a female tenon, thereby forming at least three hollow structures, which greatly improves the heat insulation effect.

[0045] The linear body 1 is also provided with first opening groove structures 12 respectively formed on two opposite side walls along the thickness direction of the hand frame, which penetrate the length direction of the linear body 1. The two first opening groove structures 12 are respectively connected with a through hole 11. The frame and the thermal insulation partition are assembled to form a whole, and then the two sides are covered with the air conditioner case shell or the partition plate shell. The first opening groove structure 12 is closed by the shell, and a moisture-inducing structure is formed at the same time, which further reduces the possibility of condensation on the outer layer.

[0046] The L-shaped corner 2 is provided with a second opening groove structure 22 on two opposite side walls along the thickness direction of the frame, and the opening of the second opening groove structure 22 is connected with the first opening groove structure 12 to form an annular opening channel located on two opposite side walls in the thickness direction of the frame. The first opening groove and the second opening groove are connected to form an annular hollow structure, which is conducive to airflow flowing therein to cut off heat and draw moisture.

[0047] Step structures are formed on both side walls of the frame along the thickness direction, and the thickness of the frame close to the partition is smaller than the thickness of the frame away from the partition. The step structure can form a gap between the air conditioner case shell 4 or the partition plate shell and the hand frame for gluing, and stable bonding is achieved through sufficient colloid.

[0048] A penetrating annular inwardly concave shallow groove structure 3 is formed in the middle of the outer surface of the frame facing away from the partition.

[0049] The straight body and L-shaped corner of the frame are both integrally formed structures of PVC material.

[0050] According to the basic phenomenon of heat transfer, heat is generally used to measure the change in internal energy during the heat transfer process. Heat transfer methods are divided into heat convection, heat conduction, and heat radiation. In fact, these three heat transfer methods often coexist at the same time, which also increases the complexity of calculating the heat transfer process.

[0051] (1) Heat conduction:

[0052] The phenomenon of heat transfer from one part of a system to another or from one system to another is called heat conduction. Heat conduction is the main way of heat transfer in solids. In the heat conduction process with gases or liquids, it often occurs simultaneously with heat convection. The heat conduction diagram of a steady-state flat wall is shown in the figure below. Figure 1 shown.

[0053] First, find out the relationship between the conduction heat flux q and the flat wall temperature and thickness.

[0054] Thermal conductivity does not change with temperature, that is, λ can be regarded as a constant.

[0055] According to Fourier's Cooling Theorem;

[0056]

[0057] Where:

[0058] q: unit heat flow

[0059] t1, t2: Temperature on both sides of the flat wall

[0060] x1, x2: Heat transfer thickness of flat wall

[0061] λ: Thermal conductivity

[0062] It is obvious from the Fourier cooling theorem equation described above that the unit heat flux of heat conduction is directly proportional to the conductivity of the material and the temperature difference on both sides of the flat wall, and is inversely proportional to the thickness of the flat wall.

[0063] (2) Heat convection:

[0064] Thermal convection is a unique way of heat transfer in liquid and gaseous fluids. The convection phenomenon of gaseous fluids is significantly more vigorous than that of liquid fluids.

[0065] Convection can be divided into natural convection and forced convection. Natural convection often occurs naturally and is caused by uneven temperature. Forced convection is caused by the disturbance of the fluid due to external influences, that is, increasing the flow rate of liquid or gas will accelerate the convective heat transfer. The thermal convection diagram of a steady-state flat wall is shown in Figure 2 shown.

[0066] For the thermal convection of a steady flat wall, first find out the relationship between the thermal convection amount q and the flat wall temperature and the surrounding temperature. The thermal conductivity does not change with temperature, that is, λ can be regarded as a constant.

[0067] (a) Basic principle of heat convection:

[0068] The most critical parameter in the process of thermal convection is the thermal convection coefficient, also known as the convection heat transfer coefficient. According to Newton's Cooling Theorem, the convection heat between the fluid and the solid wall is proportional to the temperature difference between the two fluids and the convection coefficient, that is:

[0069] Newton's Cooling Theorem;

[0070] q=hx(tw-t∞)-------------(2)

[0071] Q=hx A x(tw-t∞)=qx A------------(3)

[0072] Where:

[0073] q: The heat exchanged between the solid surface and the fluid per unit area per unit time, also known as heat flux density, unit (kcal / h) / m 2 ;

[0074] h: Convection heat transfer coefficient, unit kcal / m 2 .h.℃

[0075] tw, t∞: the temperature of the solid surface and the fluid or the temperature between two fluids, in °C;

[0076] A: wall area, unit: m 2 ;

[0077] Q: heat transfer quantity on area A, unit is kcal / h;

[0078] (b) Combined heat transfer form of heat conduction and heat convection:

[0079] When heat conduction and convection transfer coexist, it means that heat will first pass through the solid surface and then exchange heat with high and low temperature fluids at the same time per unit time. During the entire heat exchange process, sensible heat transfer (conduction and convection) and latent heat transfer (evaporation) may occur simultaneously. At this time, the amount of latent heat transfer is related to the condensation temperature and evaporation temperature of the two heat exchange fluids. The total heat transfer can be calculated based on the sum of the above two formulas (Fourier cooling theorem and Newton cooling theorem). The heat transfer form of heat conduction and convection composite heat transfer is shown in the figure below. Figure 3 shown.

[0080] (3) Thermal radiation:

[0081] Objects have the instinct to emit energy outward due to their own temperature. This form of heat transfer is called thermal radiation. Although thermal radiation is also a basic form of heat transfer, it is different from heat conduction and heat convection. Radiant heat energy can transfer heat directly from one system to another without the need for a medium. Thermal radiation mainly emits energy in the form of electromagnetic wave radiation. The higher the temperature of the emitter, the stronger the radiation intensity. The typical thermal radiation heat transfer form is shown in the figure below. Figure 4 shown.

[0082] Calculation formula for radiant heat:

[0083]

[0084] ε1: emissivity

[0085] A1: Heat dissipation area m 2

[0086] Co: thermal conductivity W / hm 2 .℃

[0087] T1: Emitter temperature ℃

[0088] T2: Receiver temperature ℃

[0089] The heat transfer mode of the combined air conditioning box shell is that heat conduction accounts for the largest proportion, accounting for about 70-75% of the overall heat transfer. According to the heat conduction equation, it is an important partial differential equation that can describe how the temperature heat transfer in a region changes with time. The propagation of heat conduction in a three-dimensional equidirectional uniform medium can be expressed by an equation, where u = u (t, x, y, z) thermal conductivity, which is a function of the time variable t and the space variable (x, y, z). It is the rate of change of temperature at a point in space with respect to time. The second derivatives of uxx, uyy and uzz temperatures with respect to the three spatial coordinate axes.

[0090] The thermal conductivity coefficient (U value) is determined by the thermal conductivity, density and heat capacity of the material. If the medium considered is not the entire space, in order to obtain the unique solution of the equation, the boundary conditions of U must be specified. If the medium is the entire space, in order to obtain uniqueness, it is necessary to assume that the growth rate of the solution has an exponential upper bound, which is consistent with the experimental results. Therefore, the U value is an important key parameter that determines the overall heat transfer.

[0091] The U value is related to the thermal conductivity, thickness, density and heat capacity of the material. Therefore, the U value can be calculated according to the following equation. The reciprocal of the thermal conductivity coefficient U value is the thermal resistance coefficient R:

[0092] In the heat transfer mode of the combined air conditioner housing, heat conduction accounts for the largest proportion, accounting for about 75% of the entire heat transfer mode. Therefore, the present invention mainly analyzes based on the heat conduction equation;

[0093] According to the basic equation of heat conduction, it can be directly simplified to;

[0094] Q=Ax U xΔT------------(5)

[0095] Where Q: heat transfer, kcal / h

[0096] U: Thermal conductivity kcal / m 2 .h.℃

[0097] A: heat transfer area m 2

[0098] ΔT: Temperature difference between the two sides of the heat transfer °C

[0099] Since U value is the main parameter of heat transfer material, the ultra-thin combined frame of the present invention uses a hollow PVC frame. The total series thermal resistance coefficient (R w ), and its thermal conductivity (U w ) is the total thermal resistance (R w ), (U w )=1 / (R w ).

[0100] Thermal resistance of PVC frame (R w ) calculation formula;

[0101]

[0102] Thermal resistance of PVC frame and hollow design

[0103]

[0104] In the above two formulas;

[0105] R w : Thermal resistance coefficient of PVC frame, m 2 .h.℃ / kcal

[0106] U w : Heat transfer coefficient of PVC frame, kcal / m 2 .h.℃

[0107] h i : The heat transfer coefficient of the film inside the wall, m 2 .h.℃ / kcal

[0108] h f : heat transfer coefficient of the boundary film of the fluid outside the wall, m 2 .h.℃ / kcal

[0109] W o : The distance between the center point of the fluid space and the outer wall, m

[0110] W i : The distance between the center point of the fluid space and the inner wall, m

[0111] W m : The distance between the center point of the fluid space and the inner and outer walls (logarithmic mean), (Wo-Wi) / ln(Wo / Wi)

[0112] r o : Fouling coefficient m on the outer wall 2 .h.℃ / kcal

[0113] r i : The fouling coefficient of the inner wall m 2 .h.℃ / kcal

[0114] λ w : Thermal conductivity of PVC material, kcal / mh℃

[0115] t w : Thickness of PVC material, m

[0116] R a : Thermal resistance coefficient of air, m 2 .h.℃ / kcal

[0117] U a : Heat transfer coefficient of air, kcal / m 2 .h.℃

[0118] λ a : Thermal conductivity of the hollow air layer, kcal / mh℃

[0119] t a : Thickness distance of the hollow air layer, m

[0120] According to the above two formulas, using PVC frame and adding a hollow air layer inside the frame will increase the thermal conductivity of the entire PVC frame (U w ) value is reduced to a lower level, which can increase its heat insulation ability and achieve the goal of no condensation on the outer surface under a certain temperature difference.

[0121] The present invention performs CFD numerical simulation;

[0122] Computational Fluid Dynamics (CFD) is a widely used discipline in fluid mechanics, mainly discussing the state of liquid or gas in a static or moving state or temperature changes. Applications include: description of fluid temperature, velocity, acceleration and motion trajectory, visualization of grid settings, etc. to obtain reasonable and correct answers.

[0123] This numerical simulation model uses PVC frames of the same shape and size, and uses solid frames and hollow frames for numerical simulation. The basic assumptions are as follows: (1) The simulated fluid is air. The high temperature side is 30℃ and the low temperature side is 13℃. The viscosity coefficient and thermal diffusion coefficient of air are ignored.

[0124] (2) Air is not affected by buoyancy caused by temperature changes.

[0125] (3) The simulation boundary conditions are the same, that is, the temperature conditions set for the high temperature side and the low temperature side are the same.

[0126] CFD temperature field numerical simulation:

[0127] Based on the above situation, this ultra-thin combined frame was invented. After computational fluid dynamics (CFD), numerical simulation and comparison of temperature field were performed, it was confirmed that the hollow frame can significantly improve the temperature distribution of the solid PVC frame.

[0128] Simulation (I): Numerical simulation of temperature field of solid PVC frame, such as Fig. 9 shown.

[0129] Result analysis:

[0130] The temperature of the temperature layer inside the solid PVC frame is evenly distributed. Although its thermal insulation effect can meet the standard temperature difference of the air-conditioning box, its thermal insulation performance is poor. If the temperature difference between the inside and outside of the air-conditioning box increases instantly, there is a high possibility of condensation on the high-temperature side.

[0131] Simulation (II): Numerical simulation of temperature field of hollow PVC frame, such as Fig.10 Results analysis:

[0132] The temperature layers in the hollow PVC frame are distributed in high and low levels, and the temperature change in the air layer is small, that is, the heat transfer is low. From the numerical simulation results, it can be clearly seen that its thermal insulation effect is better than that of the solid PVC frame, and of course it is more suitable for use under the standard temperature difference of the air-conditioning box.

[0133] Through the comparison and analysis of the numerical simulation results of the above two conditions;

[0134] (1) The hollow frame has an increased air layer, so the heat transfer rate is significantly lower, which means the heat transfer coefficient is relatively low and the insulation effect is better.

[0135] (2) Due to the good insulation effect, under the same temperature difference, its thickness can of course be thinner, which can also reduce material costs.

[0136] (3) Due to its thin thickness, the weight of the entire air-conditioning box unit is also lighter, and the space occupied can be relatively reduced.

Claims

1. An ultra-thin combined frame, characterized in that: It includes a frame that can be fixedly mounted on the outer surface of the partition made of thermal insulation material, and a hollow structure is formed inside the frame. The thickness of the frame is 25mm; The frame comprises a straight body (1) and an L-shaped corner (2), and the two ends of the L-shaped corner can be fixedly spliced ​​with the ends of the straight body to form an integrated structure; The straight body and the L-shaped corner are fixedly connected by a tenon structure; The linear body is an extruded profile, and has at least three through holes formed therein, which penetrate the length direction of the linear body and are arranged at intervals along the thickness direction thereof. The middle through hole forms a female tenon of the tenon structure. The side walls at both ends of the L-shaped corner are respectively provided with outwardly protruding male tenons (21), and the male tenons can be tightly inserted into the female tenons. The L-shaped corner is provided with a second opening groove structure (22) on two opposite side walls along the thickness direction of the frame, and the opening of the second opening groove structure is connected to the first opening groove structure to form an annular opening channel located on the two opposite side walls in the thickness direction of the frame; A first opening groove structure (12) penetrating the length direction of the linear body is respectively formed on two opposite side walls of the linear body along the thickness direction of the frame, and the two first opening groove structures are respectively connected to a through hole.

2. The ultra-thin combined frame according to claim 1, characterized in that: Step structures are respectively formed on the two side walls of the frame along the thickness direction, and the thickness dimension of the side of the frame close to the partition is smaller than the thickness dimension of the side away from the partition.

3. The ultra-thin combined frame according to claim 1, characterized in that: A penetrating annular inwardly concave shallow groove structure (3) is formed in the middle of the outer surface of the frame facing away from the partition.

4. The ultra-thin combined frame according to claim 1, characterized in that: The straight body and L-shaped corner of the frame are both integrally formed structures of PVC material.

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