With known heating elements, e. g. when used in buses, it is usual to arrange con- vectors along the side walls near the floor. The use of convectors results in a warm air stream towards the ceiling, which passes over the side walls and windows of the bus. This usually results in a colder air stream over the floor from the centre of the bus towards the side walls. As a consequence thereof, temperatures will tend to be higher near the ceiling than near the floor. This uneven temperature distribution and the colder air stream over the floor can be perceived as uncomfortable by the passen- gers of the bus. The convector is usually provided with a cover plate which is adapted to be essentially cold, in order to eliminate the risk of burning the passen- gers.

It is also known to use radiators in buses, which results in the floor covering and seats of the bus being radiantly heated. The side walls of the bus will be partially heated by the rising warm air. Radiators render a more evenly distributed temperature from floor to ceiling and also give the passengers of the bus a sensation of comfort- able warmth. In the narrow spaces available in most buses there is however not enough space available to rely solely on radiators, which require more space than convectors in order to provide the same heating effect. Therefore there is often a need for supplementary interior heaters with blowers.

The problem of achieving sufficient capacity and rendering the passengers a com- fortable climate in the bus with compact units using either of these known solutions is worsened still by the fact that there is a tendency today towards lower coolant tem- peratures in the new generations of engines for this kind of vehicles. Therefore there is a need for compact heating elements, which render an even temperature distribu- tion and with sufficient heating capacity at these lower coolant temperatures.

The object of the present invention is to provide an arrangement, which can eliminate the disadvantages of the known heating elements. This object is achieved according to the invention in that said heating element comprises the characterising features according to claim 1.

Preferred embodiments of the present invention also comprise one ore more of the characterising features according to the dependent claims.

Preferred embodiments of the invention will be further explained below with refer- ence to the enclosed drawings, in which: Fig 1 shows a heating element according to a first embodiment of the present in- vention.

Fig 2 shows a section through the heating element according to fig 1 and specifi- cally through the heat transfer means thereof.

Fig 3 shows a second embodiment of a heating element, wherein the fins and stripes of heat conducting glue are used to affect controlled heat transfer to the cover plate.

Fig 4 shows a section through the heating element according to fig 2.

With reference to fig 1,1 denotes a heating element in the form of a so called heating plinth. The heating plinth is a heating element, used at the base of a wall or close to the floor, which has a constant cross-section parallel to the floor and whose height exceeds its thickness and the width of which has the largest dimension, often the full length of the floor. The heating element 1 includes a convector. The convector com- prises two pipes 2, which are arranged to conduct a heating medium, usually water, e. g. the coolant of a bus engine. Fins 3 are mounted transversely on said pipes 2, with a mutual spacing between them. These fins 3 are arranged to increase the surface adapted for heat transfer by convection. The heating element 1 also comprises mounting means 4 for attachment of said convector to an adjacent surface. These mounting means 4 are shown as two corresponding halves, which are adapted to be joined so as to enclose a section of the pipes 2 and to be fastened to the adjacent sur- face by means of a screw 5. The heating element 1 further includes a cover plate 6

with openings therein allowing for a flow of air through the heating element over the fins 3 of the convector. Fastening means for attachment of said cover plate 6 to said convector are formed integrally with the mounting means 4 for attachment of said convector to the adjacent surface, in this case the cover plate 6. This is achieved through the cover plate 6 being provided with inwardly protruding latches 6a, which are formed complementary to latches 4b on said mounting means 4. When attached, the cover plate 6 at least partially covers the pipes 2 and fins 3 of the convector.

Means for transfer of heat from said pipes 2 to said cover plate 6 are formed inte- grally with the mounting means 4 for attachment of said convector to the adjacent surface. These mounting means 4 enclose a section of the pipes 2 and thereby draw heat from them. This heat is then conducted through these mounting means 4 and through contact between them and the cover plate 6 on thereto for rendering the cover plate 6 warm in order to emit radiant heat.

Fig 2 shows a section through the heating element 1 and specifically through the heat transfer means 4 according to fig 1. The two corresponding halves of the heat transfer means 4 are adapted to be mounted together so that they enclose a section of the pipes 2 in order to draw heat from them. They are further adapted to be secured to the cover plate 6 by means of a screw 5. The cover plate is, as mentioned above, pro- vided with inwardly protruding latches 6a. These latches 6a are formed complemen- tary to outwardly protruding latches 4b on said heat transfer means 4. The heat trans- fer means 4 also comprise a surface 4a adapted to be in thermal contact with the cover plate 6, in order to transfer heat thereto. The amount of heat transferred to the cover plate 6 can be controlled carefully by optimising, the number of heat transfer means 4 being used, their transfer capability and the heat conductivity of their mate- rial, in respect to the actual water temperature and the desired surface temperature.

Fig 3 shows a heating element 1 according to a second embodiment of the present invention. As in the first embodiment, in accordance with fig 1, this heating element 1 also includes a convector comprising two pipes 2, which are arranged to conduct a heating medium. Fins 3 are mounted transversely on said pipes 2, with a mutual spacing between them. These fins 3 display thin sections 3a at their rims, which are folded essentially perpendicular to the main section of the fins 3. The heating ele- ment 1 includes a cover plate 6 whose inner surface is essentially parallel to the sur- faces of said thin sections 3 a at the rims of the fins 3. The fins 3 are used as the means for transfer of heat from said pipes 2 to said thin sections 3 a adjacent to the

inner surface of said cover plate 6. Stripes 7 of heat conducting glue or other suitable heat conducting adhesive are used as fastening means for attachment of said cover plate 6 to said convector as well as means for affecting controlled transfer of heat from said thin rim sections 3 a of said fins 3 to said cover plate 6, in order to render said cover plate 6 warm enough to emit radiant heat whilst being cool enough not to burn a passenger touching it.

Fig 4 shows a section through the heating element 1 according to fig 3 and particu- larly illustrates how the stripes 7 function as fastening means for attachment of said cover plate 6 to said convector as well as means for affecting the controlled transfer of heat from said thin rim sections 3 a of said fins 3 to said cover plate 6 through only permitting partial heat transfer from a limited area of the surfaces of said thin rim sections 3 a to the cover plate 6.

A method for controlling the transfer of heat from said at least one pipe 2 to said cover plate 6 in a heating element 1, according to any one of the two embodiments described above, is characterised in that the amount of heat to be transferred to the cover plate 6 is controlled through adaptation of the size of the contact surfaces be- tween the heat transfer means and the cover plate per unit of length of the heating element 1. It is also possible to adapt the heat conductivity of the material of the heat transfer means in order to control the amount of heat to be transferred to the cover plate 6. The amount of heat to be transferred to the cover plate 6 should be controlled so that the achievable maximum surface temperature, in respect of the maximum design temperature of the heating medium, is limited so as not to cause burns on a person touching the cover plate 6.

When using the heating element 1 according to the present invention, e. g. in a bus, the ability of the convector to provide a good heating effect, whilst remaining com- paratively compact, will be combined with the positive properties of the radiator. The heating elements 1 according to the invention will provide radiant heat at floor level, minimise draft over the floor and also give the passengers of the bus a sensation of comfortable warmth, especially the sensation of warm feet. Further, the inventive heating element 1 will, through the perceived radiant heat, indicate to the passengers of the bus that the heating system is working properly, as today it is not uncommon that this is questioned by the passengers when convectors with an essentially cold surface are used. The inventive heating element 1 will also eliminate the risk of

burning passengers, as is possible today when radiators are used and the coolant is very hot. Several authorities have issued rules and regulations regarding the allow- able surface temperature of radiators when used in buses or elsewhere. In order to comply with these when using a radiator, the maximum allowable temperature of the coolant must be sufficiently low to render the surface of the radiator a temperature which will not burn a passenger touching it. The lower coolant temperature will however make it necessary to use a larger radiator in order to provide the same heat- ing effect, for which there is no space in modem buses.

Although the invention has been described in relation to buses, it can also equally advantageously be applied to heating elements for domestic use, where there is a need for compact installations, e. g. in bath rooms and kitchens. It is also obvious to the person skilled in the art that the inventive heating element 1 can be used for the most divers applications, such as in ships, trains and other vehicles as well as in sta- bles and different kinds of industrial buildings.

The invention is obviously not limited to the embodiment described above by way of an example, but lends its self to modifications within the scope of the idea of the in- vention defined in the appended claims.