GB1561066A - Electric fan heater with a centrifugal flow fan impeller - Google Patents

Description

(54) ELECTRIC FAN HEATER WITH A CENTRIFUGAL FLOW FAN IMPELLER (71) We, FRITZ EICHENAUER, a German body corporate of D-6744 Kandel Pfalz, Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to an electric fan heater, more particularly for hair drying appliances including a centrifugal flow fan and suitable for heating a flow of air passing through its interior, the fan being mounted for rotation at one side only thereof.

It is desirable to produce in hair driers a flow of air which is as laminar as possible and which has as constant a temperature as possible, to provide constant conditions for treatment of hair. An outlet duct for air should also be made as short as possible in order to keep the distance of the remainder of the drier from the hair to be treated to a useful minimum. More particularly when additional parts are added to the outlet duct for air, for example air nozzles of various kinds such as are used when hair curlers are used for local drying, it is necessary to have as short an air outlet duct as possible so as to ensure simple manipulation by a person using an appliance.

In previously proposed hair driers for example, heating elements with helically coiled heating wires have been used, which elements have been situated in an arrangement of a ring within the outlet duct for air.

Heating elements have also been previously proposed wherein flat heating wires have been held in a helical arrangement in holding plates, and have been mounted downstream of a fan, in relation to the intended direction of flow of the air, in the outlet duct for air. In other previously proposed heating fans a helically coiled heating wire has been placed on a supporting and insulating core and has been secured in holders on insulated parts; heating elements of this kind have also been arranged in the outlet duct for air downstream of a fan in relation to the intended direction of flow of air.

In all the previously proposed hair driers long outlet ducts for air have always been required in which ducts the heating elements have been able to be mounted. Because of varying flows of air from the fan, there has been a risk that because of local overheating housings of the outlet ducts for air, which are usually made of plastics material, may also be affected.

It is an object of the present invention to provide an electric fan heater, suitable for heating a flow of air passing through its interior, wherein the above-indicated disadvantages are eliminated or substantially reduced.

According to the present invention, therefore, we provide an electric fan heater which comprises a generally annular centrifugal flow fan mounted for rotation at one side only thereof, a heating element being arranged radially inwardly of the fan and substantially completely within the cylinder of revolution described in use by the fan, and leads for electric current for the heating element passing through the other side of the fan, the arrangement being such that in use heated air flows centrifugally from the fan from within the fan.

By construction and arrangement of the heating element in such a way, two important advantages are obtained, since an outlet duct for air is no longer used to accommodate the heating element, the length of the duct can be kept to a minimum. Furthermore the arrangement of the heating element radially inwardly of the fan, i.e. in the fan rotor, results in an intensive stirring and mixing of the air and thus gives a very uniform temperature.

Formation of the heating element is not subject to any limitations-apart from a necessity to adapt it to available space within the fan rotor. It preferably comprises a heating conductor helically wound on a supporting element, but the conductor may also be arranged in zigzag manner or in a star formation and being situated coaxially with the fan. Finally, the heating element may also comprise a flat strip of wire gauze.

An embodiment is preferred wherein the heating element is divided into sections which can be switched independently of one another and connections of which are taken out of the open end face of the fan rotor.

The invention will now be more particularly described with reference to the accompanying drawings, wherein: Figure 1 shows in diagrammatic view a hair drier with a heating element arranged within a fan impeller, in a section at right angles to the axis of a fan; and Figure 2 is a sectional view, taken along the line 11-11 of Figure 1, of the hair drier shown in Figure 1.

A hair drier shown in Figure 1 comprises a housing of plastics material which is given the general reference numeral 1 and on one end face of which there is secured a lowpotential difference motor 2 a shaft of which carries a centrifugal fan or impeller 3 of annular form. A circuit to the motor 2 and a helically wound heating element 6 is controlled by switches 5 which are arranged in a handle 4. When the drier is in use, the fan impeller 3 draws air in through air suction slots 7 (Figure 2) which are arranged laterally on the housing 1 (Figure 2) and through radially arranged air vanes 8 (Figure 2) into the interior of the fan impeller 3 which is driven by the lowpotential difference motor 2.The air heated by the heating element 6 passes out into the free atmosphere through the air outlet duct 10 (Figure 1), flowing, on its way, through blades 9 arranged on the periphery of the fan rotor 3. A protective grid 11 terminates the air outlet duct 10.

Figure 2 shows the general arrangement shown in Figure 1, in section taken along the line Il-Il of Figure 1, to show the position of the heating element 6 within the fan rotor 3. Conveniently, the low-potential difference motor 2 and the heating element 6 are secured on a holding plate 12 which is held on the housing 1 by screws 13.

The invention described with the help of a constructional example representing a hair drier is not, of course, limited to this kind of application but may also be embodied as electric fan heaters of all kinds used for any desired purposes.

WHAT WE CLAIM IS: 1. An electric fan heater which comprises a generally annular centrifugal flow fan mounted for rotation at one side only thereof, a heating element being arranged radially inwardly of the fan substantially completely within the cylinder of revolution described in use by the fan, and leads for electric current for the heating element passing through the other side of the fan, the arrangement being such that in use heated air flows centrifugally from the fan from within the fan.

2. A fan heater as claimed in claim 1, wherein the heating element comprises a heating conductor helically coiled on a supporting element.

3. A fan heater as claimed in claim 2, wherein the heating element is arranged in zigzag manner.

4. A heating fan as claimed in claim 2, wherein the heating element is arranged in a star formation and is situated coaxially with the fan.

5. A heating fan as claimed in any of claims 1 to 4, wherein the heating element comprises a flat strip of wire gauze.

6. A fan heater as claimed in any one of claims 1 to 5, wherein the heating element is divided into sections which can be switched independently of one another and connections of which are taken out of the open end face of the fan rotor.

7. An electric fan heater, substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawing.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. Formation of the heating element is not subject to any limitations-apart from a necessity to adapt it to available space within the fan rotor. It preferably comprises a heating conductor helically wound on a supporting element, but the conductor may also be arranged in zigzag manner or in a star formation and being situated coaxially with the fan. Finally, the heating element may also comprise a flat strip of wire gauze. An embodiment is preferred wherein the heating element is divided into sections which can be switched independently of one another and connections of which are taken out of the open end face of the fan rotor. The invention will now be more particularly described with reference to the accompanying drawings, wherein: Figure 1 shows in diagrammatic view a hair drier with a heating element arranged within a fan impeller, in a section at right angles to the axis of a fan; and Figure 2 is a sectional view, taken along the line 11-11 of Figure 1, of the hair drier shown in Figure 1. A hair drier shown in Figure 1 comprises a housing of plastics material which is given the general reference numeral 1 and on one end face of which there is secured a lowpotential difference motor 2 a shaft of which carries a centrifugal fan or impeller 3 of annular form. A circuit to the motor 2 and a helically wound heating element 6 is controlled by switches 5 which are arranged in a handle 4. When the drier is in use, the fan impeller 3 draws air in through air suction slots 7 (Figure 2) which are arranged laterally on the housing 1 (Figure 2) and through radially arranged air vanes 8 (Figure 2) into the interior of the fan impeller 3 which is driven by the lowpotential difference motor 2.The air heated by the heating element 6 passes out into the free atmosphere through the air outlet duct 10 (Figure 1), flowing, on its way, through blades 9 arranged on the periphery of the fan rotor 3. A protective grid 11 terminates the air outlet duct 10. Figure 2 shows the general arrangement shown in Figure 1, in section taken along the line Il-Il of Figure 1, to show the position of the heating element 6 within the fan rotor 3. Conveniently, the low-potential difference motor 2 and the heating element 6 are secured on a holding plate 12 which is held on the housing 1 by screws 13. The invention described with the help of a constructional example representing a hair drier is not, of course, limited to this kind of application but may also be embodied as electric fan heaters of all kinds used for any desired purposes. WHAT WE CLAIM IS:

1. An electric fan heater which comprises a generally annular centrifugal flow fan mounted for rotation at one side only thereof, a heating element being arranged radially inwardly of the fan substantially completely within the cylinder of revolution described in use by the fan, and leads for electric current for the heating element passing through the other side of the fan, the arrangement being such that in use heated air flows centrifugally from the fan from within the fan.

2. A fan heater as claimed in claim 1, wherein the heating element comprises a heating conductor helically coiled on a supporting element.

3. A fan heater as claimed in claim 2, wherein the heating element is arranged in zigzag manner.

4. A heating fan as claimed in claim 2, wherein the heating element is arranged in a star formation and is situated coaxially with the fan.

5. A heating fan as claimed in any of claims 1 to 4, wherein the heating element comprises a flat strip of wire gauze.

6. A fan heater as claimed in any one of claims 1 to 5, wherein the heating element is divided into sections which can be switched independently of one another and connections of which are taken out of the open end face of the fan rotor.

7. An electric fan heater, substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawing.