CA1073510A - Heating element for electrical appliances having a blower - Google Patents
Heating element for electrical appliances having a blowerInfo
- Publication number
- CA1073510A CA1073510A CA253,018A CA253018A CA1073510A CA 1073510 A CA1073510 A CA 1073510A CA 253018 A CA253018 A CA 253018A CA 1073510 A CA1073510 A CA 1073510A
- Authority
- CA
- Canada
- Prior art keywords
- heating element
- loops
- linear row
- disposed
- pairs
- Prior art date
- Legal status (The legal status 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 status listed.)
- Expired
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
- H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
- H05B2203/002—Heaters using a particular layout for the resistive material or resistive elements
- H05B2203/004—Heaters using a particular layout for the resistive material or resistive elements using zigzag layout
Landscapes
- Resistance Heating (AREA)
Abstract
S P E C I F I C A T I O N
HEATING ELEMENT FOR ELECTRICAL APPLIANCES HAVING A BLOWER
ABSTRACT OF THE DISCLOSURE
A heating element for an electrical appliance having a blower (e.g. a fan heater or a hair drier) comprises a wire looped in linear formation (e.g. zig-zag or sinuous) the loops being held in position by support plates so that there are at least two loop rows transverse to the air flow direction and disposed in succession in that direction and so that the loops in one of those rows are placed opposite to gaps in the other. In an element having four loop rows with a centre tapping for two-stage power control the electrical connections are disposed on only one support plate with the centre tapping connection at the same side side of the plate as the mains supply connections; also, the loops in a first pair of rows are aligned with one another and are offset from the loops in the second pair which are also aligned with one another.
HEATING ELEMENT FOR ELECTRICAL APPLIANCES HAVING A BLOWER
ABSTRACT OF THE DISCLOSURE
A heating element for an electrical appliance having a blower (e.g. a fan heater or a hair drier) comprises a wire looped in linear formation (e.g. zig-zag or sinuous) the loops being held in position by support plates so that there are at least two loop rows transverse to the air flow direction and disposed in succession in that direction and so that the loops in one of those rows are placed opposite to gaps in the other. In an element having four loop rows with a centre tapping for two-stage power control the electrical connections are disposed on only one support plate with the centre tapping connection at the same side side of the plate as the mains supply connections; also, the loops in a first pair of rows are aligned with one another and are offset from the loops in the second pair which are also aligned with one another.
Description
10~3510 The invention relates to heating elements for electrical appliances having a blower, such as fan heaters, hair driers or the like, the heating element comprising a re-sistance heating wire which is looped in linear formation, for example zig-zag or meander (sinuous) formation, with a plurality of rows of loops disposed in succession transversely of the flow direction of the air and having support plates which are dis-posed parallel to the flow direction of the air and which secure the rows of loops in position~
Heating elements of such cGnstruction are known (e.g. from German Patent specifications 1,185,743 and 1,256,335~.
Because of their favourable thermal and electrical behaviour and also their self-supporting properties, these heating ele- --; ments have proved satisfactory and are primarily employed ln space heaters, hair driers or the like. The rows or series of loops, advantageously six rows in succession with two-stage power control, are in this case so arranged in positions con-gruent with one another relatively to the flow direction of the air that the loops of each row are aligned with the corresponding loops of the ad~acent rows parallel to the flow direction of the air.
Tests have shown that, in the operation of heating elements of this construction, it is not readily possible to increase the heating capacity, for example by ln-creasing the number of rows of loops connected in series or by increasing the electrical power with the number of loop rows and the blower output remaining the same, be-cause the flow resistance acting against the flowing air "
. ~ '.
: ., : , .- - . - . .
:~C)73510 becomes so great that the increased heating power can no longer be discharged to the air flowing past, but only as heat radiation, and therefore the flow resistance is to a very strong degree dependent on temperature. The efficiency of such a heating element, namely the power delivered as heat to the flowing air per unit of electrical power, is therefore - :
highly dependent on the value of the flow resistance because, if the flow resistance becomes too great, much of the heat which is generated electrically can only be discharged as infra-red radiation.
An object of the invention is to reduce the flow resistance in operation of heating elements of the kind initially referred to above, having given external dimensions, and thus to improve the efficiency thereof.
In general terms, the present invention provides, in a heating element for electrical appliances having a blower . . _ . . . _ _ . .
for discharging, in a discharge direction, air through said heating element, said heating element comprising a resistance heating wire wound in a zig-zag linear row formation disposed in a single plane, wherein a plurality of said linear row formations are disposed in succession transversely of said discharge direction, and two generally planar supporting plates spaced from each other and disposed generally parallel with said discharge direction, for supporting said plurality of linear row formations, wherein loops of each zig-zag of each linear row formation are secured to the respective one of said two supporting plates, the improvement comprising at least two said linear row formations each having a plurality of said loops, the loops of one linear row formation being offset with respect to the loops of another linear row formation in a direction generally coincident with a plane parallel with said plates and transverse with respect to said discharge direction.
- ~, . , :
1~73510 Surprisingly, it has been found that with such an arrangement, to which one would attribute a greater flow re-sistance because of the larger number of items disposed across the air flow direction in the flow duct, the flow resistance ~-when the heating element is in operation, that is to say with heated loops, is smaller than is the case with the known heating elements according to the appropriate prior art. Therefore, the efficiency of such heating elements is improved by this feature according to the invention.
According to one preferred constructional form, the loops of two adjacent rows are in alignment in the flow direction and are offset from the loops of other rows.
In an alternative constructional form, the loops of adjacent rows are offset from one another.
Instead of the six rows of loops hitherto necessary with a two-stage construction, a heating element according to the invention requires only four rows of loops, which corresponds to a total saving as regards cost for material and assembly of about 40%, while having the same output and with a flow resistance which at least does not become greater. Furthermore, the construction of the heating element with only four rows of loops permits a subdivision into two groups of rows disposed in succession, the individual loops in the rows within each group being in alignment relatively to the air flow direction, and the loops of different groups being, however, offset transversely of the air flow direction.
It is possible, in connection with a heating element having only four rows of loops, for a centre tapping on -the loops, provided for controlling the power output, to be disposed at the same aide of the support plate as that to which the mains voltage supply leads are also secured. This ...... ..
~35~0 ~ :
facilitates the assembly~ of the heating element its~elf and the fitting thereof in other appliances, since the cable of the centre tapping does not have to be led back to the other side.
With heating elements having six rows of loops~, on the contrary, the mains voltage supply leads and the centre tapping are always secured to different sides of the support plate, These and other features, details and advantages of the invention will be apparent from the following description of an embodiment thereof and also fro~ the drawing, wherein:
Fig. 1 shows a heating element in a partially cut away longitudinal view, and Fig. 2 shows the heating element according to Fig. 1 in a fragmentary plan view.
~ Referring to the drawing, the heating element ; illustrated comprises essentially a resistance heating wire 1, which is looped in zig-zag or sinuous linear formation.
The loops are arranged in rows in several successive planes, only one row being partially shown in Fig. 1. The necessary three-dimensional rigidty is provided for the resistance heating wire 1 by two support plates 2 which are disposed parallel to one another and are formed with rows of holes 3 (four rows in the illustrated example). These support plates are fitted from both sides on to the preformed loops and are pushed on to these latter for a certain dlstance. As a result, the two wires of each loop fit in a respective one of the holes 3.
' The two support plates 2 are connected to one another by .~ . , .
spacer members 4, for example in the form of sheet metal strips;
in the constructional example illustrated, these strips engage by means of a U-shaped portion 5 around the support plates 2, which are rectangular, on their narrow sides It can be seen from Fig. 2 that the four rows of '73510 loops 7, 7', 7~, 7"' are disposed in succession relatively to the flow direction of the air indicated by the arrow 6 and :
are arranged in pairs 7, 7' and 7", 7"~, res:pectively, each. pair being congruent or having the loops of one ro~ in alignment w~i,th those of the other. The respective pairs of loop rows are offset relatively to one another transvers,ely o~ the ~low~
direction of the air which is indicated by the arrow 6~ so that ~:
gaps in the rows 7", 7"' are opposite to the loops of the rows 7, 7~, and vice versa.
10:
, .
'- :
s''`:~
'~:
. .
Heating elements of such cGnstruction are known (e.g. from German Patent specifications 1,185,743 and 1,256,335~.
Because of their favourable thermal and electrical behaviour and also their self-supporting properties, these heating ele- --; ments have proved satisfactory and are primarily employed ln space heaters, hair driers or the like. The rows or series of loops, advantageously six rows in succession with two-stage power control, are in this case so arranged in positions con-gruent with one another relatively to the flow direction of the air that the loops of each row are aligned with the corresponding loops of the ad~acent rows parallel to the flow direction of the air.
Tests have shown that, in the operation of heating elements of this construction, it is not readily possible to increase the heating capacity, for example by ln-creasing the number of rows of loops connected in series or by increasing the electrical power with the number of loop rows and the blower output remaining the same, be-cause the flow resistance acting against the flowing air "
. ~ '.
: ., : , .- - . - . .
:~C)73510 becomes so great that the increased heating power can no longer be discharged to the air flowing past, but only as heat radiation, and therefore the flow resistance is to a very strong degree dependent on temperature. The efficiency of such a heating element, namely the power delivered as heat to the flowing air per unit of electrical power, is therefore - :
highly dependent on the value of the flow resistance because, if the flow resistance becomes too great, much of the heat which is generated electrically can only be discharged as infra-red radiation.
An object of the invention is to reduce the flow resistance in operation of heating elements of the kind initially referred to above, having given external dimensions, and thus to improve the efficiency thereof.
In general terms, the present invention provides, in a heating element for electrical appliances having a blower . . _ . . . _ _ . .
for discharging, in a discharge direction, air through said heating element, said heating element comprising a resistance heating wire wound in a zig-zag linear row formation disposed in a single plane, wherein a plurality of said linear row formations are disposed in succession transversely of said discharge direction, and two generally planar supporting plates spaced from each other and disposed generally parallel with said discharge direction, for supporting said plurality of linear row formations, wherein loops of each zig-zag of each linear row formation are secured to the respective one of said two supporting plates, the improvement comprising at least two said linear row formations each having a plurality of said loops, the loops of one linear row formation being offset with respect to the loops of another linear row formation in a direction generally coincident with a plane parallel with said plates and transverse with respect to said discharge direction.
- ~, . , :
1~73510 Surprisingly, it has been found that with such an arrangement, to which one would attribute a greater flow re-sistance because of the larger number of items disposed across the air flow direction in the flow duct, the flow resistance ~-when the heating element is in operation, that is to say with heated loops, is smaller than is the case with the known heating elements according to the appropriate prior art. Therefore, the efficiency of such heating elements is improved by this feature according to the invention.
According to one preferred constructional form, the loops of two adjacent rows are in alignment in the flow direction and are offset from the loops of other rows.
In an alternative constructional form, the loops of adjacent rows are offset from one another.
Instead of the six rows of loops hitherto necessary with a two-stage construction, a heating element according to the invention requires only four rows of loops, which corresponds to a total saving as regards cost for material and assembly of about 40%, while having the same output and with a flow resistance which at least does not become greater. Furthermore, the construction of the heating element with only four rows of loops permits a subdivision into two groups of rows disposed in succession, the individual loops in the rows within each group being in alignment relatively to the air flow direction, and the loops of different groups being, however, offset transversely of the air flow direction.
It is possible, in connection with a heating element having only four rows of loops, for a centre tapping on -the loops, provided for controlling the power output, to be disposed at the same aide of the support plate as that to which the mains voltage supply leads are also secured. This ...... ..
~35~0 ~ :
facilitates the assembly~ of the heating element its~elf and the fitting thereof in other appliances, since the cable of the centre tapping does not have to be led back to the other side.
With heating elements having six rows of loops~, on the contrary, the mains voltage supply leads and the centre tapping are always secured to different sides of the support plate, These and other features, details and advantages of the invention will be apparent from the following description of an embodiment thereof and also fro~ the drawing, wherein:
Fig. 1 shows a heating element in a partially cut away longitudinal view, and Fig. 2 shows the heating element according to Fig. 1 in a fragmentary plan view.
~ Referring to the drawing, the heating element ; illustrated comprises essentially a resistance heating wire 1, which is looped in zig-zag or sinuous linear formation.
The loops are arranged in rows in several successive planes, only one row being partially shown in Fig. 1. The necessary three-dimensional rigidty is provided for the resistance heating wire 1 by two support plates 2 which are disposed parallel to one another and are formed with rows of holes 3 (four rows in the illustrated example). These support plates are fitted from both sides on to the preformed loops and are pushed on to these latter for a certain dlstance. As a result, the two wires of each loop fit in a respective one of the holes 3.
' The two support plates 2 are connected to one another by .~ . , .
spacer members 4, for example in the form of sheet metal strips;
in the constructional example illustrated, these strips engage by means of a U-shaped portion 5 around the support plates 2, which are rectangular, on their narrow sides It can be seen from Fig. 2 that the four rows of '73510 loops 7, 7', 7~, 7"' are disposed in succession relatively to the flow direction of the air indicated by the arrow 6 and :
are arranged in pairs 7, 7' and 7", 7"~, res:pectively, each. pair being congruent or having the loops of one ro~ in alignment w~i,th those of the other. The respective pairs of loop rows are offset relatively to one another transvers,ely o~ the ~low~
direction of the air which is indicated by the arrow 6~ so that ~:
gaps in the rows 7", 7"' are opposite to the loops of the rows 7, 7~, and vice versa.
10:
, .
'- :
s''`:~
'~:
. .
Claims (8)
1. In a heating element for electrical appliances having a blower for discharging, in a discharge direction, air through said heating element, said heating element comprising a resistance heating wire wound in a zig-zag linear row formation disposed in a single plane, wherein a plurality of said linear row formations are disposed in succession transversely of said discharge direction, and two generally planar supporting plates spaced from each other and disposed generally parallel with said discharge direction, for supporting said plurality of linear row formations, wherein loops of each zig-zag of each linear row formation are secured to the respective one of said two supporting plates, the improvement comprising at least two said linear row formations each having a plurality of said loops, the loops of one linear row formation being offset with respect to the loops of another linear row formation in a direction generally coincident with a plane parallel with said plates and transverse with respect to said discharge direction.
2. A heating element according to claim 1, wherein at least two pairs of said linear row formations are disposed in succession, said linear row formations being aligned within each of said two pairs and each of said two pairs of linear row formations being offset with respect to one another transversely of the air flow.
3. A heating element according to claim 2, wherein the aligned loops of each linear row formation of one of said two pairs are offset from the aligned loops of each linear row formation of the other of said two pairs.
4. A heating element according to Claim 3, wherein only two pairs of said linear row formations are disposed in succession.
5. A heating element according to Claim 4, wherein voltage supply leads and a tap for power output control are provided on said supporting plates, all connections being disposed on only one of said two supporting plates.
6. A heating element according to Claim 1, 2 or 3 wherein only two pairs of said linear row formations are disposed in succession.
7. A heating element according to Claim 1, 2 or 3 wherein voltage supply leads and a tap for power output control are provided on said supporting plates, all connections being disposed on only one of said two supporting plates.
8. A heating element according to Claim 1, 2 or 3 wherein said resistance heating wire is a single continuous straight wire wound in said zig-zag linear row formation in said single plane.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA253,018A CA1073510A (en) | 1976-05-20 | 1976-05-20 | Heating element for electrical appliances having a blower |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA253,018A CA1073510A (en) | 1976-05-20 | 1976-05-20 | Heating element for electrical appliances having a blower |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1073510A true CA1073510A (en) | 1980-03-11 |
Family
ID=4106011
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA253,018A Expired CA1073510A (en) | 1976-05-20 | 1976-05-20 | Heating element for electrical appliances having a blower |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1073510A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8629377B2 (en) | 2007-07-20 | 2014-01-14 | Mabe Canada Inc. | Heater assembly for clothes dryer |
-
1976
- 1976-05-20 CA CA253,018A patent/CA1073510A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8629377B2 (en) | 2007-07-20 | 2014-01-14 | Mabe Canada Inc. | Heater assembly for clothes dryer |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |