CN109323232B - Steam generator with upper and lower box bodies and vacuum insulated panels with different heat conductivity coefficients - Google Patents
Steam generator with upper and lower box bodies and vacuum insulated panels with different heat conductivity coefficients Download PDFInfo
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- CN109323232B CN109323232B CN201710828235.3A CN201710828235A CN109323232B CN 109323232 B CN109323232 B CN 109323232B CN 201710828235 A CN201710828235 A CN 201710828235A CN 109323232 B CN109323232 B CN 109323232B
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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
- F22B1/284—Methods of steam generation characterised by form of heating method in boilers heated electrically with water in reservoirs
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
- F22B37/00—Component parts or details of steam boilers
- F22B37/02—Component parts or details of steam boilers applicable to more than one kind or type of steam boiler
- F22B37/04—Component parts or details of steam boilers applicable to more than one kind or type of steam boiler and characterised by material, e.g. use of special steel alloy
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Abstract
The invention provides a steam generator with upper and lower box bodies and vacuum insulation panels with different heat conductivity coefficients, which comprises a box body, an electric heating pipe, a cold water inlet and a steam outlet, wherein the box body comprises an inner wall and an outer wall, the vacuum insulation panel is arranged between the inner wall and the outer wall, and heat insulation materials are filled in the space between the vacuum insulation panel and the inner wall and between the vacuum insulation panel and the outer wall, and the box body comprises an upper box body, a lower box body and a vertical box body which is connected with the upper box body and the lower box body. The steam generator provided by the invention has the advantages that through the design that the heat conduction coefficients of the vacuum heat insulation plates in the upper box body and the lower box body are different, the basically same heat insulation effect can be realized, meanwhile, the cost of the evaporator is reduced, or the heat insulation efficiency is improved under the condition of the same cost.
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 upper and lower box bodies and vacuum insulation panels with variable heat conductivity coefficients, which saves cost and improves the heat preservation effect by means of the heat conductivity coefficient change of the vacuum insulation panels.
In order to achieve the purpose, the invention adopts the following technical scheme:
the utility model provides a steam generator that vacuum insulation panels coefficient of heat conductivity changes, steam generator includes box, electric heating pipe, cold water inlet and steam outlet, the box includes inner wall and outer wall, set up vacuum insulation panels between inner wall and the outer wall, space filling insulation material between vacuum insulation panels, inner wall and the outer wall, the box includes upper portion box, lower part box and connects the vertical box of upper portion box and lower part box, its characterized in that, the vacuum insulation panels's of upper portion box and lower part box coefficient of heat conductivity is different, and wherein the vacuum insulation panels coefficient of heat conductivity of lower part box is less than the vacuum insulation panels coefficient of heat conductivity of upper portion box.
Preferably, the thermal conductivity of the vacuum insulation panel of the lower chamber is 0.85 to 0.95 times that of the vacuum insulation panel of the upper chamber.
Preferably, the thermal conductivity of the vacuum insulation panel of the lower chamber is 0.9 times that of the vacuum insulation panel of the upper chamber.
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 right-angled minor face is M, and the length of a side of right-angled long limit is L, and the adjacent distance of adjacent triangle-shaped fin is S on same radial electric heating rod, then satisfies following requirement:
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 design of the invention that the vacuum insulation panels of the upper and lower box bodies of the evaporator have different heat conduction coefficients achieves the effects of saving cost and increasing heat preservation by changing the heat conduction coefficient or improves the heat preservation efficiency under the condition of the same cost.
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 steam generator box according to the present invention showing the thickness variation of the upper and lower boxes;
FIG. 3 is a schematic view of a preferred embodiment of the present invention showing the variation of the interval between the upper and lower steam generator cases;
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 an inner wall 411 and an outer wall 412, a vacuum insulation board 11 is arranged between the inner wall 411 and the outer wall 412, insulation materials are filled in spaces among the vacuum insulation board 11, the inner wall 411 and the outer wall 412, and the box body comprises an upper box body 421, a lower box body 422 and a vertical shell 41 which is connected with the upper box body and the lower box body.
It should be noted that fig. 2 does not show the vacuum insulation panels in the vertical portions in order to illustrate the thickness variation of the vacuum insulation panels of the upper and lower cases, but does not show the vacuum insulation panels in the vertical portions.
As a first preferred embodiment, as shown in fig. 2, the vacuum insulation panels 11 of the upper and lower cases 411 and 412 have different thicknesses, wherein the thickness of the vacuum insulation panel 11 of the upper case 411 is smaller than that of the vacuum insulation panel 11 of the lower case 412. Thereby the whole heat preservation effect of the lower box body is higher than that of the upper box body.
In the steam generator, although the water with high temperature flows upwards and the water with low temperature flows downwards due to density in the steam generator, the temperature of the water at the lower part of the steam generator is lower than that of the water at the upper part of the steam generator, the water at the upper part and the upper box body generally have a certain distance, and the distance is provided with steam, the lower water is directly contacted with the lower box body, the heat conductivity coefficient of the gas is far lower than that of the water, so that the lower part is easier to conduct heat, and the lower box body is generally directly contacted with the ground or not exposed to the air, and the heat conductivity coefficient of the air is lower than that of the ground, so that the lower box body is easier to dissipate heat relative to the upper box body. Aiming at the situation, the thicknesses of the upper box body and the lower box body of the vacuum heat insulation plate are different, so that the heat insulation effect adopted by the upper box body and the lower box body is different. The lower box body is provided with a thick heat insulation plate, so that the heat insulation effect of the upper box body is increased in a targeted manner. Through the arrangement, the cost can be saved by more than 12% 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.
Preferably, the thickness of the vacuum insulation panel of the lower tank is 1.1 to 1.3 times that of the vacuum insulation panel of the upper tank.
Preferably, the thickness of the vacuum insulation panel of the lower tank is 1.15 times that of the vacuum insulation panel of the upper tank.
Through the setting of above-mentioned preferred heat preservation plate thickness, can realize the best effect of cost-saving.
Preferably, all vacuum insulation panels are of the same material.
Preferably, all of the vacuum insulation panels have the same thermal conductivity.
Preferably, the interval between the vacuum insulation panels adjacent to the upper casing is the same as the interval between the vacuum insulation panels adjacent to the lower casing.
As a second preferred embodiment, the thermal conductivity of the vacuum insulation panels 11 of the upper tank 411 and the lower tank 412 are different, wherein the thermal conductivity of the vacuum insulation panel 11 of the lower tank 411 is smaller than the thermal conductivity of the vacuum insulation panel 11 of the upper tank 412. Thereby the whole heat preservation effect of the lower box body is higher than that of the upper box body.
In the steam generator, although the water with high temperature flows upwards and the water with low temperature flows downwards due to density in the steam generator, the temperature of the water at the lower part of the steam generator is lower than that of the water at the upper part of the steam generator, the water at the upper part and the upper box body generally have a certain distance, and the distance is provided with steam, the lower water is directly contacted with the lower box body, the heat conductivity coefficient of the gas is far lower than that of the water, so that the lower part is easier to conduct heat, and the lower box body is generally directly contacted with the ground or not exposed to the air, and the heat conductivity coefficient of the air is lower than that of the ground, so that the lower box body is easier to dissipate heat relative to the upper box body. Aiming at the situation, the heat conduction coefficients of the upper box body and the lower box body are different by arranging the vacuum heat insulation plates, so that the heat insulation effects of the upper box body and the lower box body are different. The lower box body is provided with the heat insulation plate with low heat conductivity coefficient, so that the heat insulation effect of the upper box body is increased in a targeted manner. Through the arrangement, the cost can be saved by more than 12% 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 thermal conductivity of the vacuum insulation panel of the lower chamber is 0.85 to 0.95 times that of the vacuum insulation panel of the upper chamber.
Further preferably, the thermal conductivity of the vacuum insulation panel of the lower case is 0.9 times that of the vacuum insulation panel of the upper case.
Through the setting of above-mentioned preferred heated board coefficient of heat conductivity, can realize the best effect of cost saving.
Preferably, all the vacuum insulation panels have the same thickness.
Preferably, the interval between the vacuum insulation panels adjacent to the upper casing is the same as the interval between the vacuum insulation panels adjacent to the lower casing.
As a third preferred embodiment, as shown in fig. 3, the adjacent vacuum insulation panels 11 of the upper and lower cases 411 and 412 are preferably spaced at different intervals, wherein the interval between the adjacent vacuum insulation panels 11 of the lower case 411 is smaller than the interval between the adjacent vacuum insulation panels 11 of the upper case 412. Thereby the whole heat preservation effect of the lower box body is higher than that of the upper box body.
In the steam generator, although the water with high temperature flows upwards and the water with low temperature flows downwards due to density in the steam generator, the temperature of the water at the lower part of the steam generator is lower than that of the water at the upper part of the steam generator, the water at the upper part and the upper box body generally have a certain distance, and the distance is provided with steam, the lower water is directly contacted with the lower box body, the heat conductivity coefficient of the gas is far lower than that of the water, so that the lower part is easier to conduct heat, and the lower box body is generally directly contacted with the ground or not exposed to the air, and the heat conductivity coefficient of the air is lower than that of the ground, so that the lower box body is easier to dissipate heat relative to the upper box body. Aiming at the situation, the vacuum insulation panels are arranged at different intervals between the upper box body and the lower box body, so that the heat insulation effect of the upper box body and the heat insulation effect of the lower box body are different. The lower box body is provided with the heat insulation plate with low heat conductivity coefficient, so that the heat insulation effect of the upper box body is increased in a targeted manner. Through the arrangement, the cost can be saved by more than 12% 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 interval between the vacuum insulation panels of the lower chamber is 0.88 to 0.94 times the interval between the vacuum insulation panels of the upper chamber.
More preferably, the interval between the vacuum insulation panels of the lower chamber is 0.9 times the interval between the vacuum insulation panels of the upper chamber.
Through the setting of above-mentioned preferred heat preservation board interval, can realize the best effect of cost-saving.
Preferably, all the vacuum insulation panels have the same thickness.
Preferably, all of the vacuum insulation panels have the same thermal conductivity.
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 right-angled minor face is M, the length of the long side of the right-angled major face is L, and the adjacent distance of the adjacent triangular cooling 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 the average value of the lengths of the two long sides of the right angle of the adjacent triangular radiating fins.
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 (4)
1. A steam generator with upper and lower box bodies and vacuum insulation panels with different heat conductivity coefficients comprises a box body, an electric heating pipe, a cold water inlet and a steam outlet, wherein the box body comprises an inner wall and an outer wall, a vacuum insulation panel is arranged between the inner wall and the outer wall, and heat insulation materials are filled in spaces between the inner wall and the outer wall;
the heat conductivity coefficient of the vacuum heat insulation plate of the lower box body is 0.85-0.95 times that of the vacuum heat insulation plate of the upper box body; the cold water inlet is arranged on the side wall of the box body, the upper part of the box body is provided with the exhaust port, the electric heating pipe is arranged in the box body and comprises an outer pipe and an electric heater arranged in the outer pipe, the electric heating pipe is arranged in the vertical direction, the lower part of the electric heating pipe is provided with a water inlet channel, the water in the box body can be ensured to enter the electric heating pipe for heating, and the upper part of the electric heating pipe is connected with the steam outlet;
the center of electric heating pipe sets up along axial direction's central electric heating rod and along many radial electric heating rods of central electric heating rod to radial extension, radial electric heating rod is last to set up many triangle-shaped fin from radial electric heating rod outwards extension.
2. The steam generator of claim 1, wherein the thermal conductivity of the vacuum insulation panel of the lower tank is 0.9 times that of the vacuum insulation panel of the upper tank.
3. 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.
4. The steam generator as claimed in claim 1, wherein the cross-section of the housing is square, and the cross-section of the electric heating tube is circular.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710828235.3A CN109323232B (en) | 2017-09-14 | 2017-09-14 | Steam generator with upper and lower box bodies and vacuum insulated panels with different heat conductivity coefficients |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710828235.3A CN109323232B (en) | 2017-09-14 | 2017-09-14 | Steam generator with upper and lower box bodies and vacuum insulated panels with different heat conductivity coefficients |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109323232A CN109323232A (en) | 2019-02-12 |
| CN109323232B true CN109323232B (en) | 2020-03-24 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201710828235.3A Expired - Fee Related CN109323232B (en) | 2017-09-14 | 2017-09-14 | Steam generator with upper and lower box bodies and vacuum insulated panels with different heat conductivity coefficients |
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Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201866468U (en) * | 2010-11-11 | 2011-06-15 | 太仓宏大方圆电气有限公司 | Wet superfine glass wool vacuum insulation panel |
| CN202901702U (en) * | 2012-11-12 | 2013-04-24 | 苏州维艾普新材料有限公司 | Ultrathin laminated vacuum insulated panel core material |
| CN205908943U (en) * | 2016-07-26 | 2017-01-25 | 福建赛特新材股份有限公司 | Enhancement mode vacuum insulation panels insulation can |
| 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 |
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| CN109323232A (en) | 2019-02-12 |
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