CN109323229B - Steam generator with variable space of vacuum insulation panel - Google Patents
Steam generator with variable space of vacuum insulation panel Download PDFInfo
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- CN109323229B CN109323229B CN201710827665.3A CN201710827665A CN109323229B CN 109323229 B CN109323229 B CN 109323229B CN 201710827665 A CN201710827665 A CN 201710827665A CN 109323229 B CN109323229 B CN 109323229B
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- vacuum insulation
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
- F22B1/00—Methods of steam generation characterised by form of heating method
- F22B1/28—Methods of steam generation characterised by form of heating method in boilers heated electrically
Abstract
The invention provides a steam generator with variable vacuum insulation board spacing, which comprises a box body, an electric heating pipe, a cold water inlet and a steam outlet, wherein the box body comprises a vertical part and a horizontal part, the vertical part comprises an inner wall and an outer wall, a vacuum insulation board is arranged between the inner wall and the outer wall, heat insulation materials are filled in spaces between the vacuum insulation boards and the inner wall and between the outer wall, the spacing between the adjacent vacuum insulation boards is different, and the spacing between the adjacent vacuum insulation boards is continuously reduced along the height direction of the vertical part. The steam generator can realize basically the same heat preservation efficiency and reduce the cost of the evaporator at the same time by the design of changing the space of the vacuum heat insulation plates in the height direction.
Description
Technical Field
The invention relates to the technical field of boilers, in particular to a steam generator with a novel structure.
Background
Steam generators are mechanical devices that utilize the heat energy of a fuel or other energy source to heat water into steam. The steam generator has wide application field and is widely applied to places such as clothing factories, dry cleaning shops, restaurants, bunkers, canteens, restaurants, factories and mines, bean product factories and the like.
The existing steam generator mostly adopts gas or fuel oil for heating, and the heating efficiency is low, and the existing electric heating steam generator mostly adopts an electric heating pipe arranged at the bottom of a water supply tank for directly heating water in the water supply tank to generate steam. The electric heating steam generator has the problems of slow heating and low heat efficiency.
For example, chinese patent document CN2071061U discloses a steam generator for beauty treatment and health care, which comprises a metal electrode plate, a housing made of heat-resistant plastic, a steam outlet cover plate, an internal baffle plate, and a movable handle, wherein the metal electrode plate must be connected to a power supply through a power line, the housing is provided with an internal baffle plate, the upper opening is provided with the steam outlet cover plate, and the housing is provided with a socket groove at the bottom outside for connecting with the movable handle with a socket. An improved electric heating steam generator for generating steam, as disclosed in chinese patent document CN2651594Y, comprises a main body cavity and an electric heater, wherein the electric heater is disposed in the main body cavity, a partition board is disposed in the main body cavity to separate the cavity from the upper and lower parts, the upper cavity is a steam cavity, the lower cavity is a heating water cavity, and a steam through hole is disposed on the partition board; the partition boards have 2-6 layers, transition chambers are formed among the partition boards, and the steam through holes on the adjacent partition boards are arranged in a staggered mode. The electric heater heats water in the heating water cavity, and steam enters the steam cavity for standby through the partition plate and the transition chamber formed by the partition plate. The electric heating steam generators disclosed in the above two patent documents belong to the product.
Steam generator requires highly to the thermal-insulated effect of casing, and ordinary material is used for as steam generator wall body thermal-insulated effect poor, and in order to reach better thermal-insulated effect, the thermal insulation material thickness of use is great for steam generator consumptive material volume is too big, has increased the construction cost in the intangible. Therefore, the adoption of light materials as the heat-insulating wall body of the steam generator is particularly important.
The vacuum insulated panel (VIP panel) is one of vacuum insulation materials, is formed by compounding a filling core material and a vacuum protection surface layer, effectively avoids heat transfer caused by air convection, so that the heat conductivity coefficient can be greatly reduced and is less than 0.003 w/m.k, and the VIP panel does not contain any ODS material, has the characteristics of environmental protection, high efficiency and energy saving, and is the most advanced high-efficiency insulation material in the world at present. Vacuum insulation panels are also currently used for water tank insulation, for example, CN202339023A applies vacuum insulation panels to solar water tank insulation, and CN104180534A applies vacuum insulation panels to water heater insulation.
However, the cost requirements of the vacuum insulation panels are high, and the cost requirements of the vacuum insulation panels are also high due to different thicknesses, different thermal conductivity, the number of vacuum insulation panels used and the like. The larger the thickness of the vacuum insulation plate is, the better the heat insulation effect is, but the cost is increased greatly, the lower the heat conductivity coefficient is, the better the heat insulation effect is, but the higher the cost is, the more the vacuum insulation plates are distributed, the better the heat insulation effect is, but the cost is also high. Therefore, the invention provides a novel steam generator, which achieves the effect of heat preservation and simultaneously achieves the effect of saving cost.
Disclosure of Invention
The invention aims to provide a steam generator with variable vacuum insulation board spacing, which achieves the purposes of saving cost and improving the heat preservation effect by changing the vacuum insulation board spacing.
In order to achieve the purpose, the invention adopts the following technical scheme:
the utility model provides a steam generator, steam generator includes box, electric heating pipe, cold water inlet and steam outlet, the box includes vertical portion and horizontal part, vertical portion includes inner wall and outer wall, set up vacuum insulation panel between inner wall and the outer wall, space packing insulation material between vacuum insulation panel, inner wall and the outer wall, vacuum insulation panel's coefficient of heat conductivity is different, along the direction of height in vertical portion, the continuous reduction of the coefficient of heat conductivity of vacuum insulation panel 11.
Preferably, the thermal conductivity of the vacuum insulation panel is continuously reduced along the height direction of the vertical part, and the thermal conductivity is continuously increased.
Preferably, the thermal conductivity of the lowermost vacuum insulation panel is 1.18 to 1.39 times that of the uppermost vacuum insulation panel.
Preferably, the thickness of the lowermost vacuum insulation panel is 1.29 times that of the uppermost vacuum insulation panel.
Preferably, the thermal insulation material is polyurethane.
As preferred, the cold water entry sets up on the lateral wall of box, box upper portion set up the gas vent, electric heating pipe sets up in the box, electric heating pipe includes the outer tube and sets up the electric heater in the outer tube, electric heating pipe is vertical direction setting, electric heating pipe lower part sets up inhalant canal, guarantees that the hydroenergy of box can enter electric heating pipe and heat, and electric heating pipe's upper portion connection steam outlet.
Preferably, the outer diameter of the steam outlet pipe is smaller than the outer diameter of the outer pipe of the electric heating pipe.
Preferably, the cross section of the box body is square, and the cross section of the electric heating pipe is circular.
Preferably, the electric heating pipe is arranged at the middle position of the box body.
Preferably, the outer diameter of the outer tube of the electric heating tube is 0.3 to 0.45 times the inner diameter of the case.
Preferably, the water inlet channel is a strip-shaped slit.
Preferably, the water inlet channel is arranged below 50% of the water level of the box body.
Preferably, the center of the electric heating pipe is provided with a central electric heating rod along the axial direction and a plurality of radial electric heating rods extending along the central electric heating rod in the radial direction, and the radial electric heating rods are provided with a plurality of triangular radiating fins extending outwards from the radial electric heating rods.
Preferably, the triangular radiating fins are right-angled triangular radiating fins, the short sides forming right angles are positioned on the radial rods, and the long sides extend outwards from the radial rods; a plurality of triangular radiating fins are arranged on each radial electric heating rod, and the plurality of triangular radiating fins are similar;
the relative acute angle of the right-angled short side is M, the side length of the right-angled long side is L, and the adjacent distance of the adjacent triangular radiating fins on the same radial electric heating rod is S, so that the following requirements are met:
tan(M)=a*tan(S/L)3-b*(S/L)2+ c (S/L) -d, where tan is a trigonometric function, a, b, c, d are parameters;
61.0<a<61.5,
60.0<b<60.5,
21<c<22，
2.2< d <2.3, 4< M <35 °, preferably 8< M <25 °
0.18<S/L<0.38。
The invention has the following advantages:
1) the space between the vacuum heat insulation plates of the steam generator is changed along the height direction, and the effects of saving cost and improving heat insulation are achieved through the change of the space.
2) According to the invention, the vacuum heat insulation plate is matched with polyurethane to serve as a warehouse plate heat insulation material, so that the heat insulation performance of the box body is greatly improved, and the steam generator is more energy-saving and environment-friendly compared with a conventional steam generator.
3) The invention designs a steam generator with a novel structure, and the steam generator can realize the rapid steam supply through one device, has the functions of rapid heating, uniform temperature distribution, safety and reliability, and improves the heating efficiency.
4) According to the invention, the distribution density and area of the holes at the bottom of the electric heating tube along the height direction and the arrangement of the distance change of the multiple rows of holes are arranged, so that the heating efficiency is further improved, and the safety performance of the steam generator is improved.
5) The invention designs a novel vertical tubular electric heating tube, the upper part of the electric heating tube is directly communicated with the steam outlet, and the heating efficiency can be further improved through the mechanism.
6) The invention designs the change of the electric heating efficiency along the height direction, and can further improve the safety performance and the heating performance of the device.
7) The electric heating tube with the novel inner radiating fin structure is designed, and the triangular radiating fins of the electric heating tube with the novel structure increase the heating area and the disturbance of fluid, and improve the heating effect.
8) The invention determines the optimal relation of the inner radiating fins through numerical simulation and a large number of experiments, further improves the heating effect, and provides an optimal reference basis for the design of the electric heating tube with the structure.
Description of the drawings:
FIG. 1 is a schematic structural view of a steam generator housing of the present invention;
FIG. 2 is a schematic view of a preferred embodiment of the invention showing the variation in thickness of the vertical portion of the steam generator box;
FIG. 3 is a schematic view of a preferred embodiment of the variation of the distance between the vertical parts of the steam generator box according to the present invention;
fig. 4 is a schematic view illustrating a preferred structure of the steam generator for generating hot water and steam according to the present invention.
Fig. 5 is a schematic view illustrating a preferred structure of the steam generator for generating only steam according to the present invention.
Fig. 6 is a schematic cross-sectional structure of an electric heating tube.
Fig. 7 is a schematic diagram of the dimensions of the fins in the electric heating tube.
Fig. 8 is a schematic longitudinal sectional view of an electric heating tube.
In the figure: 1-a box body; 2-an electric heating tube; 3-a cold water inlet; 4-hot water outlet; 5-a steam outlet; 6-an exhaust port;
11-vacuum insulation panels; 12-polyurethane rigid foam;
21-an outer tube; 22-radial electric heating rod; 23-triangular fins; 24-a central electrical heating rod; 25-opening of pores
41-vertical part, 42-horizontal part, 411-inner wall, 412-outer wall.
Detailed Description
Fig. 1-8 illustrate a steam generator. As shown in fig. 4, the steam generator includes a case 1, an electric heating pipe 2, a cold water inlet 3, a hot water outlet 4, and a steam outlet 5.
The box body 1 comprises a vertical part 41 and a horizontal part 42, as shown in fig. 1, the vertical part 41 comprises an inner wall 411 and an outer wall 412, a vacuum insulation panel 11 is arranged between the inner wall 411 and the outer wall 412, and heat insulation materials are filled in the space among the vacuum insulation panel 11, the inner wall 411 and the outer wall 412.
As a first preferred embodiment, as shown in fig. 2, the thickness of the vacuum insulation panel 11 is different, and the thickness of the vacuum insulation panel 11 is continuously increased along the height direction of the vertical portion 41 (i.e., from bottom to top). Through the thickness difference for along the direction of height, the total heat transfer coefficient of box is lower and lower, thereby makes the box heat preservation effect better and better.
Since in the steam generator hot water with a high temperature is moved upwards and cold water with a low temperature is moved downwards due to density, the temperature of the water in the lower part of the steam generator is lower than that in the upper part of the steam generator. This results in a smaller temperature difference between the inside and the outside of the lower part of the steam generator than the upper part of the steam generator. Aiming at the situation, the vacuum insulation panels are arranged to have different thicknesses at different heights, so that the insulation effects adopted at different positions are different. The thick heat insulation plate is arranged on the upper part, so that the heat insulation effect of the upper part is increased in a targeted manner. Through such an arrangement, the cost can be saved by more than 15% under the condition of realizing basically the same heat preservation. Meanwhile, under the condition of the same cost, the heat preservation effect can be improved by more than 13%.
Further preferably, the thickness of the vacuum insulation panel 11 increases continuously along the height direction of the vertical portion 41.
Numerical simulation and experiments show that the distribution rule of temperature change can be well met by setting amplitude change, so that the technical effects of reducing cost and improving heat preservation are further achieved.
Further preferably, the thickness of the uppermost vacuum insulation panel is 1.2 to 1.4 times the thickness of the lowermost vacuum insulation panel.
Further preferably, the thickness of the uppermost vacuum insulation panel is 1.3 times the thickness of the lowermost vacuum insulation panel.
Through the setting of above-mentioned preferred heat preservation plate thickness, can realize the best effect of cost-saving.
Preferably, the materials of the different vacuum insulation panels are the same.
Preferably, the thermal conductivity of the different vacuum insulation panels is the same.
Preferably, the spacing between adjacent vacuum insulation panels is the same along the height direction.
As a second preferred embodiment, the thermal conductivity of the vacuum insulation panel 11 is preferably different, and the thermal conductivity of the vacuum insulation panel 11 is continuously decreased along the height direction of the vertical portion 41 (i.e., from bottom to top). Through the coefficient of heat conductivity difference for along the direction of height, the total coefficient of heat transfer of box is more and more low, thereby makes the box heat preservation effect better and more.
Since in the steam generator the water having a high temperature is moved upwards and the water having a low temperature is moved downwards due to density, the temperature of the water in the lower portion of the steam generator is lower than that of the water in the upper portion of the steam generator. This results in a smaller temperature difference between the inside and the outside of the lower part of the steam generator than the upper part of the steam generator. Aiming at the situation, the heat conductivity coefficients of the vacuum heat insulation plates at different heights are different, so that the heat insulation effects adopted at different positions are different. The heat insulation plate with low heat conductivity coefficient is arranged on the upper part, so that the heat insulation effect of the upper part is increased in a targeted manner. Through such an arrangement, the cost can be saved by more than 15% under the condition of realizing basically the same heat preservation. Meanwhile, under the condition of the same cost, the heat preservation effect can be improved by more than 13%.
Further preferably, the magnitude of the decrease in the thermal conductivity of the vacuum insulation panel 11 along the height direction of the vertical portion 41 increases.
Numerical simulation and experiments show that the distribution rule of temperature change can be well met by setting amplitude change, so that the technical effects of reducing cost and improving heat preservation are further achieved.
Further preferably, the thermal conductivity of the lowermost vacuum insulation panel is 1.18 to 1.39 times that of the uppermost vacuum insulation panel.
Further preferably, the thickness of the lowermost vacuum insulation panel is 1.29 times the thickness of the uppermost vacuum insulation panel.
Through the setting of above-mentioned preferred heated board coefficient of heat conductivity, can realize the best effect of cost saving.
Preferably, the different vacuum insulation panels have the same thickness.
Preferably, the spacing between adjacent vacuum insulation panels is the same along the height direction.
As a third preferred embodiment, as shown in fig. 3, the spacing between the adjacent vacuum insulation panels 11 is preferably different, and the spacing between the adjacent vacuum insulation panels 11 is gradually decreased along the height direction of the vertical portion 41 (i.e., from bottom to top). Through the interval difference for along the direction of height, the distribution of vacuum insulation panel is more and more close, and the total coefficient of heat transfer of box is more and more low, thereby makes the box heat preservation effect better and more.
Since in the steam generator the water having a high temperature is moved upwards and the water having a low temperature is moved downwards due to density, the temperature of the water in the lower portion of the steam generator is lower than that of the water in the upper portion of the steam generator. This results in a smaller temperature difference between the inside and the outside of the lower part of the steam generator than the upper part of the steam generator. Aiming at the situation, the adjacent intervals of the vacuum insulation panels at different heights are different, so that the heat insulation effects adopted at different positions are different. The upper part is provided with the heat insulation plate with small space, and the heat insulation effect of the lower part is increased in a targeted manner. Through such an arrangement, the cost can be saved by more than 13% under the condition of realizing basically the same heat preservation. Meanwhile, the heat preservation effect can be improved by more than 12% under the condition of the same cost.
Further preferably, the distance between the vacuum insulation panels 11 decreases continuously along the height direction of the vertical portion 41.
Numerical simulation and experiments show that the distribution rule of temperature change can be well met by setting amplitude change, so that the technical effects of reducing cost and improving heat preservation are further achieved.
Further preferably, the pitch of the uppermost vacuum insulation panel is 0.85 to 0.92 times the pitch of the lowermost vacuum insulation panel.
Further preferably, the pitch of the uppermost vacuum insulation panel is 0.88 times the pitch of the lowermost vacuum insulation panel.
Through the setting of above-mentioned preferred heat preservation board interval, can realize the best effect of cost-saving.
Preferably, the different vacuum insulation panels have the same thickness.
Preferably, the thermal conductivity of the different vacuum insulation panels is the same.
Preferably, the three embodiments described above can be combined together.
As shown in fig. 4, the cold water inlet 3 is provided at a lower portion of the tank 1, and the hot water outlet 4 is provided at an upper portion of the tank 1. Electric heating pipe 2 sets up in the box, electric heating pipe 2 sets up for vertical direction (perpendicular to water tank bottom plane setting), and electric heating pipe 2 includes outer tube 21 and the electric heater of setting in outer tube 21, 2 lower parts of electric heating pipe set up inhalant canal, guarantee that the hydroenergy of box 1 can enter electric heating pipe 2 and heat, and steam outlet 5 is connected on electric heating pipe 2's upper portion.
Preferably, the steam outlet 5 is connected with the outer pipe of the electric heating pipe 2 in a sealing way.
Preferably, the outer diameter of the steam outlet 5 pipe is smaller than the outer diameter of the outer pipe of the electric-heating pipe 2. This can ensure the steam discharge speed.
Cold water enters the tank through cold water inlet 3. When the electric heating pipe works, the electric heating pipe 2 is arranged in the box body 1, water in the box body 1 enters the electric heating pipe 2 through the opening 25 on the outer pipe 21, then the water is heated in the electric heating pipe 2, and steam generated after heating is discharged through the steam outlet 5. Meanwhile, the electric heating pipe heats water in the box body while generating steam, and hot water generated after heating can be utilized through the hot water outlet.
Through foretell structure setting, can produce steam and hot water simultaneously for steam generator has multiple functions, has expanded the scope that it utilized, and the steam that produces is direct discharges through the steam outlet who is connected with electric heating pipe moreover, because heat the outside water of electric heating pipe through outer tube 21, therefore outside water can not the boiling evaporation, has also guaranteed the security of heating.
According to the invention, the electric heating pipe 2 is arranged in the vertical direction, so that water can be heated in the vertical direction, the water is continuously heated in the rising process, and the heating efficiency is further improved compared with the electric heating pipe arranged in the horizontal direction.
As a modification, the hot water outlet 4 may be eliminated, for example as shown in fig. 5, with the steam generator acting as a single function evaporator for generating steam.
Preferably, an exhaust port 6 is provided at the upper part of the case 1. Through setting up gas vent 6, avoid 1 internal pressure of box too big, can guarantee safety.
Preferably, the cross section of the box body is square, preferably cubic.
Preferably, the cross section of the electric-heating tube 2 is circular.
Preferably, the electric heating pipe 2 is disposed at a middle position of the case. Through so setting up, guarantee hot water heating's homogeneity.
Preferably, the outer diameter of the outer tube 21 of the electric-heating tube 2 is 0.3 to 0.45 times the inner diameter of the case 1. Further preferably 0.35 to 0.40 times.
Preferably, the water inlet channel is a strip-shaped slit.
Preferably, the water inlet passage is an opening 25. As shown in fig. 8. It should be noted that fig. 8 is only a schematic diagram, and although only 1 or one row of the openings 25 is shown between the adjacent electric heating rods 22 in fig. 8, the openings are not limited to one or one row, and a plurality of or a plurality of rows may be arranged at upper and lower positions between the adjacent electric heating rods 22.
Preferably, the opening 25 may be circular or square in shape.
Preferably, the opening 25 is provided at 50% or less of the water level of the tank 1. Through so setting up, can guarantee that hydroenergy is enough timely get into 2 insides of electric heating pipe and heat, also avoid trompil 25 to set up too high simultaneously and lead to steam to spill over from trompil 25, avoid whole box internal pressure too big, also avoid the water of eminence to get into in the electric heating pipe simultaneously, the moisture that the steam that causes the production carried is too many.
Preferably, the holes 25 are arranged in a plurality of rows in a height direction (i.e., a direction from bottom to top, hereinafter appearing in the height direction, if not specifically stated, the direction from bottom to top).
Through setting up the multirow, can guarantee that different high positions intake, avoid a single position to intake, cause the inhomogeneous of heating, avoid the water that gets into simultaneously to be evaporated, cause the heating tube dry up.
Preferably, the distribution density of the openings 25 becomes smaller and smaller along the height direction. The density of the distribution of the openings 25 is smaller and smaller, which means that the distribution of the openings is smaller and smaller, and the area of the openings is smaller and smaller.
Through a large amount of numerical simulation and experimental research thereof, it is found that the distribution density is smaller and smaller by arranging the open pores, the main reason is to ensure that most of water is heated at the lower part, and water continuously enters the electric heating pipe 2 in the rising process of the water changed into steam and is continuously heated. If the water inflow at the lower part is small, the water at the lower part may be vaporized rapidly, the pressure inside the electric heating tube 2 is too high, and the water at the upper part cannot enter the electric heating tube due to the pressure. The drying of the electric heating pipe is reduced, and the heating efficiency is improved.
Further preferably, the distribution density of the openings 25 is continuously increased with a smaller and smaller amplitude along the height direction.
Through a large amount of experiments and numerical simulation, through the change of foretell trompil distribution density, can further improve heating efficiency, improve the output efficiency of steam, can reduce the dryout in the electric heating pipe simultaneously.
Preferably, the area of the single opening 25 becomes smaller and smaller along the height direction. Further preferably, the area of the individual openings 25 increases with decreasing amplitude along the height direction. For specific reasons see the variation in the distribution density of the openings 25.
Preferably, the sum of the areas of the openings 25 in each row becomes smaller and smaller in the height direction. Preferably, the sum of the areas of the openings 25 in each row increases in the height direction to a smaller and smaller extent. For specific reasons see the variation in the distribution density of the openings 25.
Preferably, the distance between each row of the open holes 25 is larger and larger along the height direction. Preferably, the spacing between each row of the openings 25 increases in the height direction. For specific reasons see the variation in the distribution density of the openings 25.
Preferably, the electric heating tube 2 is centrally provided with a central electric heating rod 24 along the axial direction.
Preferably, the heating power per unit length of the electric heating rod 24 is continuously reduced along the height direction. The heating power of the electric heating rod 24 is continuously reduced, so that the fluid at the lower part is rapidly heated, then the hot fluid flows to the upper part through natural convection, and the fluid at the upper part and the fluid outside the electric heating pipe 2 at the lower part rapidly enter, so that the heating efficiency can be further improved. Through a large amount of experiments and numerical simulation, the heating efficiency can be further improved by about 10% through the change of the heating power of the electric heating pipe, and the heating time is saved.
Preferably, the magnitude of the continuous decrease in the heating power per unit length of the electric heating rod 24 is continuously increased along the height direction.
Through a large amount of experiments and numerical simulation, the heating efficiency can be further improved by 5% through the change of the heating power amplitude of the electric heating rod 24, and the heating time is further saved.
Preferably, the electric heating rod 24 is divided into a plurality of stages, and heating powers per unit length of the different stages are different in the height direction. Wherein the heating power per unit length of the different segments is continuously reduced along the height direction. Further preferably, the magnitude of the decrease is continuously increased.
Preferably, the length of each segment is the same.
Preferably, the heating power per unit length of each segment is the same.
The specific reason is as described above.
By providing the segments, manufacturing can be further facilitated.
The electric heating tube 2 is provided with a plurality of radial electric heating rods 22 extending radially along a central electric heating rod 24, and a plurality of triangular cooling fins 23 extending outwards from the radial electric heating rods 22 are arranged on the radial electric heating rods 22.
The radial electric heating rod 22 and the triangular radiating fins 23 extending outwards along the radial electric heating rod 22 are arranged, so that the heating efficiency can be further improved, the heating area is increased, and the heating effect is improved.
Further preferably, the cross section of the radial electric heating rod is rectangular, preferably square.
Further preferably, the radial electric heating rod is circular in cross section.
Preferably, the heating power of the radial electric heating rod per unit length is 0.3-0.5 times, preferably 0.4 times that of the central electric heating rod.
Preferably, the radial electric heating rod 22 is a rod-shaped object extending from the center of the circle to the inner wall of the electric heating tube 21 along the radial direction.
Preferably, a plurality of triangular cooling fins 23 are arranged on each radial electric heating rod 22, and the plurality of triangular cooling fins 23 are similar. Namely, three mutually corresponding internal angles of different triangular radiating fins are the same.
Preferably, the side length or area of the triangular fin 23 becomes smaller from the center of the electric-heating tube 21 to the inner wall of the electric-heating tube 21.
Preferably, triangular cooling fins 23 are distributed on both sides of the radial electric heating rod 22, and the triangular cooling fins 23 are symmetrical along the center line of the radial electric heating rod 22.
Preferably, the distance between the triangular fins 23 of adjacent radial electric heating rods 22 is kept constant.
Preferably, the distance between the triangular fins 23 of the adjacent radial electric heating rods 22 increases continuously from the center of the electric heating tube 21 to the radial direction.
By continuously increasing the distance between the triangular radiating fins 23 of the adjacent radial electric heating rods 22, the fluid flowing space at the place with large external fluid flowing amount is large, the flowing resistance can be further reduced, and the heating effect is basically kept unchanged.
Preferably, the triangular fins 23 are right-angled triangular fins, and the short sides forming the right angle are located on the radial electric heating rod, and the long sides extend outward from the radial electric heating rod.
Preferably, the radial electric heating rod 22 is a round rod with a diameter of 0.6-1.2 mm, preferably 0.8 mm.
Preferably, the triangular fins extend outwardly from the central plane of the round bar. The triangular radiating fins are of flat plate structures. The flat structure is perpendicular to the central electrical heating rod 24 and the flat structure extension passes through the centre line of the round bar.
It is known through numerical analysis and experiment that adjacent triangle-shaped fin interval can not be too big, then can cause the fin heat transfer area undersize if too big, it is not good to reinforce heat transfer effect, but the interval also can not be too little, the interval is too little, cause intraductal fluid flow space undersize, it is too big to cause the resistance that steam flows in pipe 2, the same reason, the apex angle of triangle-shaped fin can not be too big, too big also can influence flow resistance, and too big can lead to the vortex effect not good, but also can not be too little, too little if heating area is too little, also can influence heating effect. Therefore, the invention considers the two aspects of heating effect and flow resistance, so that the invention optimizes the heating effect and arranges the optimal relationship of each parameter through a large number of experiments under the condition of preferentially meeting the normal flow resistance (the total pressure bearing is less than 8 Mpa).
The relative acute angle of the short side of the right angle is M, the side length of the long side of the right angle is L, and the adjacent distance of the adjacent triangular radiating fins on the same radial electric heating rod 22 is S, so that the following requirements are met:
tan(M)=a*tan(S/L)3-b*(S/L)2+ c (S/L) -d, where tan is a trigonometric function, a, b, c, d are parameters;
61.0< a <61.5, preferably a =61.295,
60.0< b <60.5, preferably b =60.267,
21< c <22, preferably c =21.412,
2.2< d <2.3, preferably d =2.2734
4< M <35 °, preferably 8< M <25 °
0.18<S/L<0.38,0.25R<L<0.32 R。
R is the distance from the center of the electric heating tube 2 to the midpoint of the side of the right triangle where the axial fins 22 are located.
Wherein the adjacent distance S is the spacing between the sides of the adjacent triangular fins located at the axial fins 22; i.e. the distance between the rear end of the side of the axial fin 22 where the triangular fin is located and the front end of the side of the rear triangular fin located at the axial fin 22. See in particular the label of fig. 7.
Preferably, the number of the radial electric heating rods 22 is 7-9, and the included angles formed between the adjacent radial electric heating rods 22 are equal. More preferably 8.
The length L of the long side of the right angle is taken as the average of the lengths of the two long sides of the right angle of the adjacent triangular fin.
Further preferably, the inner diameter of the electric heating tube is 25 to 40 mm.
Preferably, the electric heating tube is a straight tube.
Preferably, the heating power of the steam generator is 2000-4000W, preferably 2500-3500W.
Preferably, the electrical heating rods 24, 22 are resistance heaters, and the change in heating power per unit length is changed by setting the diameter of the resistance.
Preferably, the distance between the upper and lower adjacent radial electric heating rods 22 is greater along the height direction. Further preferably, the distance between adjacent radial electric heating rods 22 increases with increasing amplitude along the height direction.
Preferably, the heating power per unit length of the different radial electric heating rods 22 becomes smaller and smaller along the height direction. Further preferably, the heating power per unit length of the different radial electric heating rods 22 is continuously increased in a smaller and smaller range.
The heating power of the electric heating rod 22 is continuously reduced in the height direction or the distance between the electric heating rods is increased, so that the fluid at the lower part is rapidly heated, then the hot fluid flows to the upper part through natural convection, and the fluid at the upper part and the fluid outside the electric heating pipe 2 at the lower part rapidly enter, so that the heating efficiency can be further improved. Through a large amount of experiments and numerical simulation, the heating efficiency can be further improved by 8-10% through the change of the heating power of the electric heating pipe, and the heating time is saved.
Although the present invention has been described with reference to the preferred embodiments, it is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (6)
1. A steam generator with variable vacuum insulation panels is characterized in that the space between adjacent vacuum insulation panels is different, and the space between the adjacent vacuum insulation panels is continuously reduced along the height direction of the vertical part;
along the height direction of the vertical part, the continuously reduced amplitude of the space between the vacuum heat insulation plates is continuously increased; the utility model discloses a refrigerator, including box, electric heating pipe, cold water inlet, box upper portion, electric heating pipe, steam outlet, cold water inlet sets up on the lateral wall of box, box upper portion set up the gas vent, electric heating pipe sets up in the box, electric heating pipe includes the outer tube and sets up the electric heater in the outer tube, electric heating pipe is vertical orientation setting, the electric heating pipe lower part sets up inhalant canal, guarantees that the hydroenergy of box can enter electric heating pipe and heat, and electric heating.
2. The steam generator of claim 1, wherein the spacing of the uppermost vacuum insulation panels is 0.85 to 0.92 times the spacing of the lowermost vacuum insulation panels.
3. The steam generator of claim 2, wherein the spacing of the uppermost vacuum insulation panels is 0.88 times the spacing of the lowermost vacuum insulation panels.
4. The steam generator of claim 1, wherein an outer diameter of the steam outlet conduit is smaller than an outer diameter of an outer tube of the electric heating tube.
5. The steam generator as claimed in claim 4, wherein the cross-section of the housing is square, and the cross-section of the electric heating tube is circular.
6. The steam generator of claim 1, wherein the electric heating tube is centrally provided with a central electric heating rod along an axial direction and a plurality of radial electric heating rods extending radially along the central electric heating rod, and the radial electric heating rods are provided with a plurality of triangular fins extending outwardly from the radial electric heating rods.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710827665.3A CN109323229B (en) | 2017-09-14 | 2017-09-14 | Steam generator with variable space of vacuum insulation panel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710827665.3A CN109323229B (en) | 2017-09-14 | 2017-09-14 | Steam generator with variable space of vacuum insulation panel |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109323229A CN109323229A (en) | 2019-02-12 |
| CN109323229B true CN109323229B (en) | 2020-07-31 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201710827665.3A Expired - Fee Related CN109323229B (en) | 2017-09-14 | 2017-09-14 | Steam generator with variable space of vacuum insulation panel |
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| CN (1) | CN109323229B (en) |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201522164U (en) * | 2009-11-04 | 2010-07-07 | 合肥美菱股份有限公司 | Refrigerator equipped with vacuum heat-insulation board |
| CN104850723A (en) * | 2015-06-08 | 2015-08-19 | 河南泛锐复合材料研究院有限公司 | Optimum design method for two-dimensional heat transfer model of phase change heat storage device |
| CN107101520B (en) * | 2017-07-07 | 2021-04-02 | 安徽科瑞克保温材料有限公司 | Inner fin heat exchange tube, condenser and mobile refrigeration house thereof |
| CN207539874U (en) * | 2017-09-14 | 2018-06-26 | 山东交通学院 | A kind of steam generator of vacuum insulation plate spacing variation |
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2017
- 2017-09-14 CN CN201710827665.3A patent/CN109323229B/en not_active Expired - Fee Related
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| Publication number | Publication date |
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| CN109323229A (en) | 2019-02-12 |
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Granted publication date: 20200731 Termination date: 20210914 |