WO1999045747A1 - Electric heater - Google Patents

Electric heater Download PDF

Info

Publication number
WO1999045747A1
WO1999045747A1 PCT/HU1999/000016 HU9900016W WO9945747A1 WO 1999045747 A1 WO1999045747 A1 WO 1999045747A1 HU 9900016 W HU9900016 W HU 9900016W WO 9945747 A1 WO9945747 A1 WO 9945747A1
Authority
WO
WIPO (PCT)
Prior art keywords
electric heater
heating resistor
wall
resistor wire
ceramic rings
Prior art date
Application number
PCT/HU1999/000016
Other languages
French (fr)
Inventor
Ferenc HOFFER KOVÁCS
Original Assignee
Hoffer Kovacs Ferenc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hoffer Kovacs Ferenc filed Critical Hoffer Kovacs Ferenc
Priority to AU29494/99A priority Critical patent/AU2949499A/en
Publication of WO1999045747A1 publication Critical patent/WO1999045747A1/en

Links

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/10—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor
    • H05B3/16—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor the conductor being mounted on an insulating base
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H3/00—Air heaters
    • F24H3/002—Air heaters using electric energy supply

Definitions

  • the present invention relates to an electric heater, comprising a heating resistor wire, applied for heating flats, offices and any other rooms.
  • the main feature of usual electric heaters including heat accumulator heaters, electrical cockle stoves or any electric heaters, is that electric current related with voltage developed on a wire of high resistivity produces heat, which is transferred to the outside by an intermediate insulation.
  • the main object of the present invention is to reduce the loss of heat. It is further an object of the present invention to minimize the loss of heat due to heat radiation and heat transfer. It is still another object of the present invention to reduce heat radiation - 2 -
  • an electric heater comprising a heating resistor wire
  • the heating resistor wire is made of iron or iron-based alloy of low resistivity
  • the tubular double-wall housing is open at both ends, and is provided with a protective metal grid at the upper end.
  • the heating resistor wire is held by ceramic rings fixed to a metal frame and is folded to sections in parallel to the longitudinal axis of the tubular double-wall housing, along the periphery of the ceramic rings.
  • the electric heater is provided with a control unit in the form of a separated thermostat built in its standard mains plug.
  • Operational temperature of the heating resistor wire which is around 300 °C in a preferred embodiment of the electric heater according to the invention, is much lower than that of the conventional electric heaters, whereas its surface heat transfer capability is higher than that of the conventional ones, thus there is no need of heat storing and heat transferring means.
  • a tubular housing is used. The cold air inside the heater gets heated by the heating resistor wire, and moves upwards at the same time. The heated air draws along the air of lower temperature from the bottom of the room. During heating this air-flow speeds up, because heat formation is limited to the volume of the air inside the housing of the electric heater according to the invention.
  • the heating resistor wire is supplied with a double-wall housing in order to avoid any accident resulted from touching a single-wall housing.
  • the air between the internal and the external wall of the housing also supports heating.
  • Both of the internal and an external wall of the double-wall housing have an upper tubular unit with circular or polygonal cross section and a bottom conical unit.
  • the electric heater according to the present invention is controlled by an external thermostat built in the standard (220 VAC) grounded mains plug of the electric heater. - 3 -
  • FIG. 1 is a perspective and partially sectional view of the preferred embodiment of the present invention.
  • FIG. 2.a is the side view of the core of the preferred embodiment of the present invention.
  • - Figure 2.b is the cross section of a ceramic ring of the core of the preferred embodiment of the present invention.
  • Figure 3. a is the side view and Figure 3.b is the cross section of the frame of the core of the preferred embodiment of the present invention.
  • FIG. 4 is the side view of the internal coverage of the core of the preferred embodiment of the present invention.
  • FIG. 1 is a perspective and partially sectional view of a preferred embodiment of the electric heater according to the invention provided with an external thermostat 17.
  • the thermostat 17 is electrically connected to the mains cable of the electric heater and is built in the one-phase mains plug of the electric heater in such a way that it allows an easy connection of the electric heater to the standard (220 VAC) mains socket.
  • the electric heater comprises heating resistor wire 15 and a double-wall housing, consisting of an external wall and an internal wall, each with an upper tubular unit 1 and 7 with a bottom conical unit 2 and 9, respectively.
  • Figure 2. a is the side view of the inner part of a preferred embodiment of the electric heater according to the invention.
  • Figure 2. a shows heating resistor wire 15 and ceramic rings 24 holding said heating resistor wire 15, whereas
  • Figure 2.b shows cross section of a ceramic ring 24.
  • the ceramic rings 24 are provided with holes arranged with equal distance from each other.
  • the ceramic rings 24 are located coaxially above each other in such a way that said holes lead the heating resistor wire 15.
  • the heating resistor wire 15 is led between the bottom and the top ceramic rings 24 by several turns.
  • FIG.a is the side view of the frame supporting the ceramic rings 24 shown in Figure 2. a, whereas Figure 3.b shows the cross section of said frame.
  • the ceramic rings are fixed on the frame by a plurality of flat steel rails 32. Each steel rail 32 has several cut-outs 33 for holding the ceramic rings 24.
  • the steel rails 32 are held at their ends by two spacers 31.
  • the steel rails 32 are attached to spacers 31 by screws 38.
  • the spacers 31 are further used to hold the steel rails 32 in a triangular arrangement and, in addition, to keep constant distance between heating resistor wire and the tubular internal wall of the electric heater.
  • Figure 4 is the side view of the internal wall of the double-wall housing of a preferred embodiment of the electric heater.
  • the tubular internal wall has a separated conical bottom 9 made from sheet steel and attached to said internal wall by welding.
  • the conical bottom 9 comprises air-convection holes on its top two-third part.
  • the bottom side of the double-wall housing is covered by a baseplate 40 made of a thick steel sheet.
  • Figure 5 is the side view of the external wall of the double-wall housing of the preferred embodiment of the electric heater.
  • the external wall has a separated conical bottom 2 made of sheet steel, and is fixed at said external wall by welding.
  • the external wall is shorter than the internal wall, but is long enough to hide the air-convection holes of the internal wall.
  • the necessary distance between the internal wall and the external wall is maintained by spacers 54 and 48 (shown in Figure 4).
  • the upper end of the double-wall housing is covered by a metal grid allowing free air convection and, on the other hand, providing mechanical protection.
  • the metal grid is preferably a closely woven metal mesh 6 fixed to the outer edge of the double-wall housing by a round steel band 55 and screws 53.
  • the electric heater according to the invention may be applied in several places, as well as in homes due to its low power, which is about 1 kW in a preferred embodiment of the invention.
  • the power of the electric heater may be increased depending on special requirements.
  • the electric heater requires no additional electrical construction of the mains due to its low current consumption.
  • the efficiency of the electric heater is improved by direct heat transfer between the heating resistor wire and the air thus reducing the loss of heat due to heat radiation.
  • the electric heater may be used to heat closed rooms or used as supplementary heating facility in rooms equipped with a different kind of heating system. There is no need of additional thermostat to control temperature of the room, because the electric heater has its own thermostat built in its mains plug.
  • the double-wall housing allows to move the electric heater during operation without risk of accident.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Resistance Heating (AREA)
  • Control Of Resistance Heating (AREA)

Abstract

An electric heater is disclosed which comprises a heating resistor wire (15). The heating resistor wire (15) is made of iron or iron-based alloy of low resistivity, is arranged within a tubular double-wall housing, comprising an internal wall (1) and an external wall (7). The tubular double-wall housing is open at both ends, and is provided with a protective metal grid at the upper end. The heating resistor wire (15) is held by ceramic rings (24) fixed to a metal frame and is folded to sections in parallel to the longitudinal axis of the tubular double-wall housing, along the periphery of the ceramic rings. The electric heater is provided with a control unit in the form of a separated thermostat built in its standard mains plug.

Description

Electric heater
The present invention relates to an electric heater, comprising a heating resistor wire, applied for heating flats, offices and any other rooms.
The main feature of usual electric heaters, including heat accumulator heaters, electrical cockle stoves or any electric heaters, is that electric current related with voltage developed on a wire of high resistivity produces heat, which is transferred to the outside by an intermediate insulation. The lower the resistivity of the wire and the higher the current in the wire is, the higher the power of the heater is at nominal voltage, which is either 220 VAC or 380 VAC. As the power increases, heat radiation of a heating resistor wire also increases. The radiated heat is stored and transferred to the outside by insulating ceramics. This technology reduces efficiency of usual electric heaters, because some of the power is lost due to heat radiation, storage and transfer of heat. In other words, the higher the radiation, the storage and the indirect heat transfer is, the more the loss of heat is. Tests carried out with conventional heating facilities have clearly shown that both fixed and portable heaters have no satisfying heat transfer capability, while their energy consumption is not linearly proportional to their efficiency. The effective power of the electric heaters, including heat accumulator heaters, electrical cockle stoves or any electric heaters, is only a part of the entire power. Moreover, heaters of the prior art are expensive and have high installation costs.
In order to eliminate the problems mentioned above, the main object of the present invention is to reduce the loss of heat. It is further an object of the present invention to minimize the loss of heat due to heat radiation and heat transfer. It is still another object of the present invention to reduce heat radiation - 2 -
and make the heat transfer as direct and efficient as possible by eliminating intermediate transferring means and, in this way, to increase efficiency of the electric heater according to the invention.
In order to achieve the foregoing and other objects, an electric heater comprising a heating resistor wire is used, in which the heating resistor wire is made of iron or iron-based alloy of low resistivity, is arranged within a tubular double-wall housing, comprising an internal wall and an external wall. The tubular double-wall housing is open at both ends, and is provided with a protective metal grid at the upper end. The heating resistor wire is held by ceramic rings fixed to a metal frame and is folded to sections in parallel to the longitudinal axis of the tubular double-wall housing, along the periphery of the ceramic rings. The electric heater is provided with a control unit in the form of a separated thermostat built in its standard mains plug.
Operational temperature of the heating resistor wire, which is around 300 °C in a preferred embodiment of the electric heater according to the invention, is much lower than that of the conventional electric heaters, whereas its surface heat transfer capability is higher than that of the conventional ones, thus there is no need of heat storing and heat transferring means. In order to increase efficiency of direct heat transfer, a tubular housing is used. The cold air inside the heater gets heated by the heating resistor wire, and moves upwards at the same time. The heated air draws along the air of lower temperature from the bottom of the room. During heating this air-flow speeds up, because heat formation is limited to the volume of the air inside the housing of the electric heater according to the invention. An unavoidable consequence of heating is warm-up of the housing, therefore the heating resistor wire is supplied with a double-wall housing in order to avoid any accident resulted from touching a single-wall housing. The air between the internal and the external wall of the housing also supports heating. Both of the internal and an external wall of the double-wall housing have an upper tubular unit with circular or polygonal cross section and a bottom conical unit. The electric heater according to the present invention is controlled by an external thermostat built in the standard (220 VAC) grounded mains plug of the electric heater. - 3 -
The invention is explained in more detail through the drawing. In the drawing:
- Figure 1 is a perspective and partially sectional view of the preferred embodiment of the present invention. - Figure 2.a is the side view of the core of the preferred embodiment of the present invention.
- Figure 2.b is the cross section of a ceramic ring of the core of the preferred embodiment of the present invention.
- Figure 3. a is the side view and Figure 3.b is the cross section of the frame of the core of the preferred embodiment of the present invention.
- Figure 4 is the side view of the internal coverage of the core of the preferred embodiment of the present invention.
- Figure 5 is the side view of the preferred embodiment of the present invention. Figure 1 is a perspective and partially sectional view of a preferred embodiment of the electric heater according to the invention provided with an external thermostat 17. The thermostat 17 is electrically connected to the mains cable of the electric heater and is built in the one-phase mains plug of the electric heater in such a way that it allows an easy connection of the electric heater to the standard (220 VAC) mains socket.
Preferably, the electric heater comprises heating resistor wire 15 and a double-wall housing, consisting of an external wall and an internal wall, each with an upper tubular unit 1 and 7 with a bottom conical unit 2 and 9, respectively. Figure 2. a is the side view of the inner part of a preferred embodiment of the electric heater according to the invention. Figure 2. a shows heating resistor wire 15 and ceramic rings 24 holding said heating resistor wire 15, whereas Figure 2.b shows cross section of a ceramic ring 24. The ceramic rings 24 are provided with holes arranged with equal distance from each other. The ceramic rings 24 are located coaxially above each other in such a way that said holes lead the heating resistor wire 15. The heating resistor wire 15 is led between the bottom and the top ceramic rings 24 by several turns. The holes of the ceramic - 4 -
rings 24 are filled with ceramics in order to fix the heating resistor wire 15, and protect it against resonance. The end portions of the heating resistor wire 15, both coming out from the lowest ceramic ring 24 and connected to the mains cable, are thickened and insulated by ring shaped ceramic insulators 26. Figure 3.a is the side view of the frame supporting the ceramic rings 24 shown in Figure 2. a, whereas Figure 3.b shows the cross section of said frame. The ceramic rings are fixed on the frame by a plurality of flat steel rails 32. Each steel rail 32 has several cut-outs 33 for holding the ceramic rings 24. The steel rails 32 are held at their ends by two spacers 31. The steel rails 32 are attached to spacers 31 by screws 38. The spacers 31 are further used to hold the steel rails 32 in a triangular arrangement and, in addition, to keep constant distance between heating resistor wire and the tubular internal wall of the electric heater.
Figure 4 is the side view of the internal wall of the double-wall housing of a preferred embodiment of the electric heater. The tubular internal wall has a separated conical bottom 9 made from sheet steel and attached to said internal wall by welding. The conical bottom 9 comprises air-convection holes on its top two-third part. The bottom side of the double-wall housing is covered by a baseplate 40 made of a thick steel sheet.
Figure 5 is the side view of the external wall of the double-wall housing of the preferred embodiment of the electric heater. Similarly to the internal wall, the external wall has a separated conical bottom 2 made of sheet steel, and is fixed at said external wall by welding. The external wall is shorter than the internal wall, but is long enough to hide the air-convection holes of the internal wall. The necessary distance between the internal wall and the external wall is maintained by spacers 54 and 48 (shown in Figure 4). The upper end of the double-wall housing is covered by a metal grid allowing free air convection and, on the other hand, providing mechanical protection. The metal grid is preferably a closely woven metal mesh 6 fixed to the outer edge of the double-wall housing by a round steel band 55 and screws 53. In view of the prior art, the present invention provides the following benefits and advantages. The electric heater according to the invention may be applied in several places, as well as in homes due to its low power, which is about 1 kW in a preferred embodiment of the invention. The power of the electric heater may be increased depending on special requirements. The electric heater requires no additional electrical construction of the mains due to its low current consumption. The efficiency of the electric heater is improved by direct heat transfer between the heating resistor wire and the air thus reducing the loss of heat due to heat radiation. Because of the low current consumption and easy connectivity to the mains, the electric heater may be used to heat closed rooms or used as supplementary heating facility in rooms equipped with a different kind of heating system. There is no need of additional thermostat to control temperature of the room, because the electric heater has its own thermostat built in its mains plug. The double-wall housing allows to move the electric heater during operation without risk of accident.

Claims

- 6 -Ciaims
1. An electric heater, comprising a heating resistor wire, characterized in that said heating resistor wire is made of iron or iron-based alloy of low resistivity, and is arranged within a tubular double-wall housing, comprising an internal and an external wall, said tubular double-wall housing is open at both ends, and is provided with a protective metal grid at the upper end, said heating resistor wire is held by ceramic rings fixed to a metal frame and is folded to sections in parallel to the longitudinal axis of said tubular double-wall housing, along the periphery of said ceramic rings, and a control unit is provided as a separated thermostat built in the standard mains plug of the electric heater.
2. The electric heater of claim 1 , characterized in that there are guide holes in said ceramic rings for said heating resistor wire.
3. The electric heater of claim 1 , characterized in that said metal frame comprises at least one metal rail fixed to said internal wall and provided with cut-outs to hold said ceramic rings,
4. The electric heater of claim 1 , characterized in that both of said internal and external wall of said double-wall housing comprise a tubular unit with either circular or polygonal cross section, and a conical unit at the bottom.
5. The electric heater of claim 1 , characterized in that said metal grid is a closely woven metal mesh fixed to said external wall.
6. The electric heater of claim 1 , characterized in that said heating resistor wire is made of steel.
7. The electric heater of claim 5, characterized in that said metal mesh is fixed by a metal band and screws to the outside of said external wall.
PCT/HU1999/000016 1998-03-04 1999-03-03 Electric heater WO1999045747A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU29494/99A AU2949499A (en) 1998-03-04 1999-03-03 Electric heater

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
HU9800473A HUP9800473A3 (en) 1998-03-04 1998-03-04 Electric expand heater
HUP9800473 1998-03-04

Publications (1)

Publication Number Publication Date
WO1999045747A1 true WO1999045747A1 (en) 1999-09-10

Family

ID=89996214

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/HU1999/000016 WO1999045747A1 (en) 1998-03-04 1999-03-03 Electric heater

Country Status (3)

Country Link
AU (1) AU2949499A (en)
HU (1) HUP9800473A3 (en)
WO (1) WO1999045747A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ITBS20130181A1 (en) * 2013-12-12 2015-06-13 Giovanni Giacomini ELECTRIC STOVE
US10555456B2 (en) 2012-12-28 2020-02-11 Positec Power Tools (Suzhou) Co., Ltd. Auto mowing system

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB191216506A (en) * 1912-03-19 1912-11-07 Victor Charles Joh Nightingall Improvements in Electric Radiators.
US2819375A (en) * 1954-10-27 1958-01-07 Bert T Mohn Space heater
US3045097A (en) * 1959-06-01 1962-07-17 William W Sellers Electric heater

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB191216506A (en) * 1912-03-19 1912-11-07 Victor Charles Joh Nightingall Improvements in Electric Radiators.
US2819375A (en) * 1954-10-27 1958-01-07 Bert T Mohn Space heater
US3045097A (en) * 1959-06-01 1962-07-17 William W Sellers Electric heater

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10555456B2 (en) 2012-12-28 2020-02-11 Positec Power Tools (Suzhou) Co., Ltd. Auto mowing system
ITBS20130181A1 (en) * 2013-12-12 2015-06-13 Giovanni Giacomini ELECTRIC STOVE

Also Published As

Publication number Publication date
HU9800473D0 (en) 1998-04-28
HUP9800473A3 (en) 2000-06-28
AU2949499A (en) 1999-09-20
HUP9800473A2 (en) 1999-11-29

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