WO2004113800A2

WO2004113800A2 - Electric boiler with a membrane heater

Info

Publication number: WO2004113800A2
Application number: PCT/KR2004/001471
Authority: WO
Inventors: Sung-Don Park
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-06-20
Filing date: 2004-06-19
Publication date: 2004-12-29
Anticipated expiration: 2005-12-20
Also published as: KR20040110776A; KR100561624B1; WO2004113800A3

Abstract

An electric boiler is provided, which comprises: a heating device including an inner tube having a fluid inlet port and a first fluid passageway, an outer tube enclosing the inner tube and having a fluid outlet port and a second fluid passageway in communication with the first fluid passageway, and a membrane heater for converting electric energy into thermal energy to heat up fluid in the second fluid passageway, the membrane heater comprised of electrically conductive paint coated on an external surface of the outer tube; a radiator device for allowing fluid-borne thermal energy to be dissipated to the outside, the radiator device including a radiant pipe connected at one end to the inlet port of the inner tube and at the other end to the outlet port of the outer tube; and a pump for forcibly circulating the fluid through the heating device and the radiator device.

Description

ELECTRIC BOILER WITH A MEMBRANE HEATER

TECHNICAL FIELD

The present invention generally relates to an electric boiler, and more particularly, to an electric boiler for generating water for heating a room or general hot water by employing a membrane heater which uses electricity as its energy source.

BACKGROUND ART As well known in the art, a boiler is an apparatus designed to generate thermal energy by using electricity or fuel such as petroleum or gas as an energy source, thereby generating water for heating a room or general hot water by heating water with the generated thermal energy. The boiler may be classified into an oil- fired boiler, a gas-fired boiler and an electric boiler in terms of an energy source. Meanwhile, the boiler using the fuel such as petroleum or gas as an energy source is expensive and complicated in configuration and has a lower productivity, since it bums the fuel and, therefore, has a number of components needed in storing, supplying, burning the fuel and in exhaust. Further, it requires a separate boiler room in which proper ventilation has to be maintained in order to supply the air needed in burning the fuel and to prevent gas poisoning due to leakage of exhaust gas.

The boiler room has to be also partitioned from regions to be heated. For these reasons, in this type of boiler, pipes laid between the boiler and the regions to be heated become complicatedly lengthened, thereby causing a heat loss and degrading efficiency in installation. As for the gas-fired boiler, the boiler has a shortcoming that a periodic inspection of a burner and pipes is burdensome. The periodic inspection is required to prevent the gas poisoning and gas explosion due to leakage of gas, which may cause significant losses of lives and properties.

Meanwhile, a prior art electric boiler is not appropriate for heating over a large area because of the electricity rates more expensive than the cost of the fuel, though it has advantages that its installation and operation are simple compared to the fuel-burning boiler since it uses electricity as an energy source. Further, the electric boiler becomes easily out of order due to cut of a heating element and has low energy efficiency. In order to save the maintenance cost of such electric boiler, a regenerative electric boiler has been developed, which is operated during midnight time at which the electricity rates are discounted, to produce hot water having a temperature about 90°. The generated hot water is stored to allow the user to use he hot water when necessary. The regenerative electric boiler, however, has to be provided with a separate reservoir for the hot water, which is positioned on a rooftop or a basement of a structure. For this reason, large initial establishment costs may be required.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to provide an electric boiler capable of producing hot water for heating a room or hot water with a low power consumption and a high efficiency. Another object of the present invention is to provide an electric boiler small in size, light in weight and simple in configuration.

Another object of the present invention is to provide an electric boiler easy to install and providing convenience in storage and carriage

Another object of the present invention is to provide an electric boiler enabling a simple piping work and enhancing a degree of freedom in a design step thereof.

In order to achieve the above object, the present invention provides an electric boiler is provided, which comprises: a heating device including an inner tube having a fluid inlet port and a first fluid passageway, an outer tube enclosing the inner tube and having a fluid outlet port and a second fluid passageway in communication with the first fluid passageway, and a membrane heater for converting electric energy into thermal energy to heat up fluid in the second fluid passageway, the membrane heater comprised of electrically conductive paint coated on an external surface of the outer tube; a radiator device for allowing fluid-borne thermal energy to be dissipated to the outside, the radiator device including a radiant pipe comiected at one end to the inlet port of the inner tube and at the other end to the outlet port of the outer tube; and a pump for forcibly circulating the fluid through the heating device and the radiator device.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a scheme of the inventive electric boiler showing an arrangement of pipes.

Fig. 2 is a perspective view of a heating device of the inventive electric boiler. Fig. 3 is a sectional view of the heating devices connected in series, which are shown in Fig. 2. Fig. 4 is a sectional view of a heating device of another embodiment of the inventive electric boiler.

Fig.5 is a sectional view when taken along a line V-V in Fig. 4.

Fig. 6 is a sectional view of a heating device of another embodiment of the inventive electric boiler.

Fig. 7 is a sectional view of a radiator device of the inventive electric boiler.

Fig. 8 is a sectional view of a radiator device of another embodiment of the inventive electric boiler.

Fig. 9 is a sectional view of a case in which the heating device, a pump and a controller of the inventive electric boiler are accommodated.

Fig. 10 is a sectional view of heating devices in a series connection in accordance with another embodiment of the inventive electric boiler.

Fig. 11 is a scheme of another embodiment of the inventive electric boiler.

MODES FOR CARRYING OUT THE INVENTION

A preferred embodiment of the inventive electric boiler will be described in detail with reference to the accompanying drawings.

Referring to Figs. 1 through 3 and 9, the inventive electric boiler is provided with a heating device 10. The heating device 10 includes an inner tube 11 of an elongated, hollow and cylindrical shape, and an outer tube 12 of a hollow cylindrical shape enclosing the inner tube 11. The inner tube and the outer tube 11, 12 serve as passageways through which fluid such as water, brine, oil, and gas flows.

A first passageway 13 of the inner tube 11 communicates with an inlet port

14 for an introduction of the fluid. The inner tube 11 has a though hole 16 at its lower end, which allows the first passageway 13 of the inner tube 11 to communicate with a second passageway 15 of the outer tube 12. The outer tube 12 has an outlet port 17 at its upper end, which communicates with the second passageway 15. The inlet port 14 of the inner tube 11 is integrally formed with the upper end of the outer tube 12 and a connecting member 18 allowing the inner tube 11 to be integrally formed with the outer tube 12 is provided in the lower ends of the inner tube 11 and the outer tube 12 to reinforce the intensity. The inner tube and the outer tube 11, 12 of the heating device can be made of material having a good heat resistance and a low expansion characteristics, e.g., quartz, glass, ceramic. Quartz is preferable, since it can endure in a hot temperature environment and has a good heat transfer efficiency.

Meanwhile, membrane heater 19 is provided on an external surface of the outer tube 12. The membrane heater 19 is one of electrically resisting bodies and can be formed by applying electrically conductive paint on the outer tube 12. A plurality of electrodes 20 are attached to a surface of the membrane heater 19 with predetermined separations given therebetween, so that electric power can be applied to the membrane heater 19. The electrode 20 has an annular shape formed along a circumference of the outer tube 12. The electrode 20 may be made of silver. The membrane heater 19 and the electrode 20 described above can be manufactured in following steps. An electrically conductive membrane having a thickness of 500 ~ 5000 A is firstly formed by applying the electrically conductive paint on an external surface of the pre-heated outer tube 12 in a manner of using clean air as a carrier. Secondly, an electrically conductive membrane to be served as the electrode 20 is printed on the aforesaid electrically conductive membrane and then dried. Finally, the outer tube 12 is made to have a proper shape. An electrical insulation material may be applied on the surface of the membrane heater 19 and the electrode 20, if necessary.

As shown in Figs. 3 and 9, in connecting two heating devices 10, 10', the outlet port 17 of one heating device 10 is connected to the inlet port 14 of the other heating device 10', to maintain a series flow of the fluid. Although two heating devices 10, 10' are illustrated in Figs. 3 and 9, the number of the heating devices 10, 10 ' can be properly increased if necessary.

Another embodiment of a heating device 10 shown in Figs. 4 and 5 has a plurality of annular partitions 22 formed in the second passageway 15 between the inner tube and the outer tube 11, 12, with separations given between them. An orifice 23 is formed through the partition 22 to allow the fluid to flow in a reduced flow rate. Since when the fluid flows in the second passageway 15 it passes the orifice 23 of the partition 22, a time period for which the fluid flows in the second passageway 15 is lengthened. Therefore, a time period for which the fluid is heated by the membrane heater 19 is prolonged, to thereby enhance the heating efficiency. Although four orifices 23 are formed through the partitions 22 in an equally separated manner in Figs. 4 and 5, the number and position of the orifices 23 and the partitions 22 may be changed properly if necessary.

Referring to Another embodiment of a heating device 10 shown in Fig. 6, it includes the inner tube 11 and the outer tube 12 separately formed from each other.

The inner tube 12 is accommodated inside the outer tube 12. A cap 24 is mounted to upper portions of the inner tube 11 and the outer tube 12 to maintain airtightness of the second passageway 15. A helical partition 25 is formed on an external surface of the inner tube 11, which is closely contacted to an inner surface of the outer tube 12 to provide a helical second passageway 15. The helical second passageway 15 lengthens a time period for which the fluid flows in the second passageway 15 and, hence, time period during which the fluid is heated by the membrane heater 19 is also prolonged. In this embodiment, the helical partition 25 may be formed on the internal surface of the outer tube 12.

Referring to Figs. 1, 7 and 9, the inventive electric boiler is provided with a radiator device 30 connected to the heating device 10. The radiator device 30 serves to dissipate the heat from the fluid being supplied, which is previously heated by the heating device 10. It is in a form of a flexible mattress 31 having a flat plate shape and includes a zigzag radiant pipe 32 connecting the inlet port 14 and the outlet port 17. One end of the radiant pipe 32 is connected to the inlet port 14 of the heating device 10 via a first connecting pipe 41 forming a tubular passageway 40, while the other end being connected to the outlet port 17 of the heating device 10 through a second connecting pipe 42.

The radiant pipe 32 of the radiator device 30 connected to the heating device 10 like this forms a passageway 33 through which the fluid flows. Meanwhile, the radiant pipe 32, the first connecting pipe 41 and the second connecting pipe 42 may be made of a material with flexibility, for example, synthetic resin, synthetic rubber, etc. The radiant pipe 32 is accommodated within a cover 34. The cover 34 may be made of various materials, e.g., synthetic resin having flexibility, fibers, and artificial leather. A cushion 35 having flexibility is positioned between the radiant pipe 32 and the cover 34. The cushion 35 may be made of synthetic resin, fibers. In installation of the radiator device 30 of this embodiment, only the radiant pipe 32 may be installed on a place to be heated, e.g., a bottom of a room, without the cover

34 or it may be replaced with an existing pipe for heating previously installed in the room.

Fig. 8 illustrates a mattress of as another embodiment of the radiator device. The mattress 36 includes a first sheet 37 and a second sheet 38 which have flexibility. A zigzag passageway 39 similar to the radiant pipe 32 of the mattress 31 described above is arranged between the first sheet and the second sheet 37, 38. The first sheet and the second sheet 37, 38 may be made of synthetic resin or vinyl. The passageway 39 between the first sheet and the second sheet 37, 38 may be formed by conventional high frequency joining of the first sheet and the second sheet 37, 38 along an edge of the passageway 39.

Referring to Figs. 1 and 9, the inventive electric boiler includes a pump 50 mounted to the tubular passageway 40 to forcibly circulate the fluid, and a controller 60. The pump 50 is mounted to the first connecting pipe 41 of the tubular passageway 40, which supplies the fluid being discharged from the mattress 31 to the inlet port 14. The pump 50 may be provided in the second connecting pipe 42. As shown in Fig. 1, a valve 43 is mounted to the first connecting pipe 41 between the inlet port 14 of the heating device and the pump 50 as a means for introducing the fluid for supplement. The user can supplement the fluid into the first connecting pipe 41 by opening the valve 43. A plug that is provided in the first connecting pipe 41 may replace the valve 43 of the means for introducing the fluid. Meanwhile, the controller 60 is equipped with a plurality of buttons 61 manipulated by the user, a timer 62 and a display 63 for displaying the operations of the electric boiler. A current adjustment 64 is connected to the controller 60, which controls a current applied to the electrodes 20 in order to adjust a heat emission temperature of the heating device 10 determined by the user's manipulating the buttons 61.

As shown in Fig. 9, all of the heating device 10, the pump 50 and the controller 60 are accommodated together within the case 70 to form a single module 71. Modularizing the heating device 10, the pump 50 and the controller 60 by accommodating all of them within the case 70 like this enables the inventive electric boiler to be installed on any place to which the electric power can be provided.

Meanwhile, a water supply pipe 80 of as a means for supplying the fluid, i.e., water, is connected to the first connecting pipe 41 between the inlet port 14 of the heating device 10 and the pump 50. A water reservoir 81 for containing water therein is mounted to the water supply pipe 80. The water reservoir 81 is connected to pipes for public or private water service. A constant water level is maintained in the water reservoir 81 by a float valve 83 for controlling the supply of water. A first solenoid valve 84 for controlling the flow of the water is mounted to the water supply pipe 80.

A hot water reservoir 90 for keeping therein hot water to be serviced is mounted to the second connecting pipe 42 between the radiator device 30 and the pump 50. The hot water reservoir 90 is connected to a second solenoid valve 92 mounted to the second connecting pipe 42 via a branch pipe 91. A manual valve 94 is mounted to a hot water discharge pipe 93 of the hot water reservoir 90. The pipes for public or private water service are connected to the manual valve 94 of the hot water discharge pipe 93. A water level of the hot water reservoir 90 is detected by a water level sensor 95 which may be implemented with a floater type liquid-level meter. The water level sensor 95 sends signals related to the water level in the hot water reservoir 90 to the controller 60. The controller 60 controls the operation of the first solenoid valve and the second solenoid valve 84, 92 according to the signals from the water level sensor 95, to thereby adjust a flow rate of the water being supplied through the water supply pipe 80 and a flow rate of the hot water being supplied to the hot water reservoir 90 through the branch pipe 91.

In Fig. 10, there is shown another embodiment of the heating device of the present invention. Each of the heating devices 110, 110' of another embodiment includes an inner tube 111 of an elongated, hollow and tubular shape, and an outer tube 112 of a hollow tubular shape enclosing the inner tube 111. A first passageway 113 of the inner tube 111 communicates with a second passageway 114 of the outer tube 112 through a plurality of holes 115 formed through a lower portion of the inner tube 111. Through the first passageway 113 of the inner tube 111 and a second passageway 114 of the outer tube 112, the fluid such as water, brine, oil, and gas flows.

Atop cap 120 is mounted to upper ends of the inner tube and the outer tube 111, 112. The first passageway 113 of the inner tube 111 communicates with an inlet port 121 of the top cap 120 for an introduction of the fluid, while the second passageway 114 of the outer tube 112 communicating with an outlet port 122 of the top cap 120 for a discharge of the fluid. Further, a bottom cap 130 is mounted to lower ends of the inner tube and the outer tube 113, 114 to block the lower ends of them. The top cap and the bottom cap 120, 130 are assembled into the upper ends and the lower ends of the inner tube and the outer tube 111, 112, respectively, to provide airtightness. The inner tube 111, the outer tube 112, the top cap 120 and the bottom cap 130 of the heating devices 110, 110' may be made of a material having a good heat resistance and a low expansion characteristics, e.g., quartz, glass, ceramic. Copper alloy or stainless steel is also possible.

Meanwhile, in connection of two heating devices 110, 110', the outlet port 122 of the heating device 110 is connected to the inlet port 121 of the heating device 110' by using a connecting pipe 123 to allow the series flow of the fluid. In this embodiment, the inlet port 121 of the heating device 110 and the outlet port 122 of the heating device 110' can be connected to the radiator device 30 shown in Figs. 1 and 9 by being connected to the radiant pipe 32 of the mattress 31. A membrane heater 19 and the electrodes 20 of the heating device 110 are identical to the membrane heater 19 and the electrodes 20 of the heating device 10 in configuration and operation and detailed description about that is omitted. Fig. 11 shows another embodiment of the inventive electric boiler. The electric boiler in this embodiment includes another heating device 10" mounted to the radiant pipe 32 of the radiator device 30. The inlet port 14 of the heating device 10" communicates with the second connecting pipe 42 of the modular type electric boiler 71 through the radiant pipe 32, while the outlet port 17 of the heating device 10" communicating with the first connecting pipe 41 of the modular type electric boiler 71 through the radiant pipe 32.

The heating device 10" configured like this heats again the fluid flowing through the radiant pipe 32, thereby preventing the fluid from being changed to have a low temperature during the flow of the fluid through the radiant pipe 32. Especially, preventing the temperature of the fluid from being lowered maximizes the efficiency in heating the room and enables a uniform and stable heating over a large area.

Next, operations of the inventive electric boiler having a configuration described above will be explained.

Referring to Figs. 1 and 9, the fluid which is introduced into the inlet port 14 of the inner tube 11 by the pump 50, i.e., the water, sequentially flows the first passageway 13 of the inner tube 11, the through hole 16 and the second passageway 15 of the outer tube 12. When the electric power is applied to the electrodes 20 by the operation of the current adjustment 64, the membrane heater 19 generates heat. The heat generated by the membrane heater 19 heats the water flowing through the first passageway and the second passageway 13, 15 of the heating device 10. The water is changed into the hot water necessary for heating a room and then discharged through the outlet port 17 of the outer tube 12. Since the water that flows through the first passageway 13 of the inner tube 11 and the second passageway 15 of the outer tube 12 in sequence is heated twice by the membrane heater 19, the energy efficiency is considerably improved for its power consumption. Further, a control of a voltage applied to the electrodes 20 by the operation of the current adjustment 64 enables rapid heating of the water. As shown in Figs. 1 and 7, the hot water for heating a room being discharged through the outlet port 17 of the outer tube 12 is supplied to the passageway 33 of the mattress 31 through the second connecting pipe 42 of the tubular passageway 40. The hot water flowing through the passageway 33 heats the heating area and at the same time the heat is dissipated from the hot water. The hot water being discharged from the passageway 33 of the mattress 31 is re-introduced into the inlet port 14 of the inner tube 11 through the first connecting pipe 41 of the tubular passageway 40 and the water circulates continuously in this manner. Since the operation of the mattress 36 shown in Fig. 8 is identical to that of the mattress 31 described above, detailed description is omitted. Since the mattress 36 and the passageway 39 thereof are formed by the high frequency joining of two sheets 37, 38, it is possible to variously modify the appearance of the mattress 36 and the shape of the passageway 39. This provides an advantage that the degree of freedom in a design step can be increased. Further, since the mattress 31 or 36 can be folded due to its flexibility, it is easily carried and kept after a reduction of size.

Referring to Fig. 9, the hot water kept in the hot water reservoir 90 can be used by opening the manual valve 94 of the hot water discharge pipe 93. When the water level of the water reservoir 81 becomes lower than a predetermined level, the water level sensor 95 detecting the water level of the water reservoir 81 sends the signals related to the water level to the controller 60. The controller 60 controls the flow rate of the water being supplied through the water supply pipe 80 and the flow rate of the water being supplied to the hot water reservoir 90 by opening the first solenoid valve and the second solenoid valve 84, 92 according the signals from the water level sensor 95. Therefore, the shortage of water resulted from the consumption of the hot water can be stably supplemented. As shown in Fig. 1 , the user can simply supplement or discharge the fluid by using the valve 43 mounted to the first connecting pipe 41 between the inlet port 14 of the heating device 10 and the pump 50.

The heating device 110 of the embodiment shown in Fig. 10 has a configuration where the inner tube 111 and the outer tube 112 have the hollow tubular shape and the inner tube 111 and the outer tube 112 separately formed from the inner tube 111 are assembled together with the top cap and the bottom cap 120, 130 being mounted to the upper ends and the lower ends of the two tubes 111, 112. Therefore, it has an advantage that it can be simply manufactured and implemented compared to the heating device 10.

Further, in the electric boiler of the embodiment shown in Fig. 11, the fluid heated by the modular electric boiler is re-heated by the heating device 10" in the course of flow through the radiant pipe 32. Therefore, the fluid circulates through the radiant pipe 32, maintaining a constant high temperature.

Meanwhile, although an explanation that the inventive electric boiler has a use for heating a room is made in the description and the drawings, the use of the inventive electric boiler is not limited to this. For example, if the radiant pipe 32 is laid under a road, a bridge and a runway of the airport, it can prevent surface freezing of those facilities by hot water.

INDUSTRIAL APPLICABILITY

As described above, in accordance with the inventive electric. boiler where the fluid sequentially flows through the first passageway and the second passageway defined by the inner tube and the outer tube, while the membrane heater of the outer tube heating the fluid flowing through the tubes, hot water having a high temperature can be obtained with a low power consumption and a high efficiency. Further, modularizing the heating device, the pump and the controller by accommodating them together in the case enables a simple installation process of those components. Further, since the radiator device for allowing heat to be dissipated from the heated fluid is made of the mattress having flexibility, the radiator device can be small in size and light in weight. Especially, the mattress having flexibility provides an easy installation, convenience in storage and carriage and hence, facilitates piping work and increases the degree of freedom in the design step.

Claims

What is claimed is:

1. An electric boiler comprising: a heating device including an inner tube having a fluid inlet port and a first fluid passageway, an outer tube enclosing the inner tube and having a fluid outlet port and a second fluid passageway in communication with the first fluid passageway, and a membrane heater for converting electric energy into thermal energy to heat up fluid in the second fluid passageway, the membrane heater comprised of electrically conductive paint coated on an external surface of the outer tube; a radiator device for allowing fluid-borne thermal energy to be dissipated to the outside, the radiator device including a radiant pipe connected at one end to the inlet port of the inner tube and at the other end to the outlet port of the outer tube; and a pump for forcibly circulating the fluid through the heating device and the radiator device.

2. The electric boiler of Claim 1, wherein said heating device further including a prolongation means for increasing a time period for which the fluid flows in the second passageway.

3. The electric boiler of Claim 2, wherein said prolongation means includes a plurality of annular partitions each of which is provided with an orifice for allowing the fluid to flow in a reduced flow rate, the annular partitions formed in the second passageway with separations given therebetween.

4. The electric boiler of Claim 2, wherein said prolongation means includes a helical partition formed in the second passageway.

5. The electric boiler of Claim 1 , further comprising: a first connecting pipe for connecting the inlet port of the inner tube to the radiant pipe of the radiator device; a second connecting pipe for connecting the outlet port of the outer tube to the radiant pipe of the radiator device; a water reservoir connected to the first connecting pipe; and a hot water reservoir connected to the second connecting pipe.

6. The electric boiler of Claim 1, further comprising a reheating device for reheating the fluid flowing through the radiant pipe of the radiator device, the reheating device mounted to a mid portion of the radiant pipe of the radiator device.

7. The electric boiler of Claim 6, wherein said reheating device including an inner tube having a fluid inlet port and a first fluid passageway, an outer tube enclosing the inner tube and having a fluid outlet port and a second fluid passageway in communication with the first fluid passageway, and a membrane heater for converting electric energy into thermal energy to heat up fluid in the second fluid passageway, the membrane heater comprised of electrically conductive paint coated on an external surface of the outer tube.