Patent Publication Number: US-2006016794-A1

Title: Strip-heating for building structures and infrastructures

Description:
The invention concerns a heating system for building structures and infrastructures.  
      The many processes and means available for surface and environmental heating in the above structures are essentially based on combustion especially using gas or electricity.  
      In the case of gas the system most widely used consists of a central boiler supplying radiators in the different rooms of a building.  
      In the second case current, circulating in electric resistances, is transformed into thermal energy.  
      These resistances reach very high temperatures, even of 1000° C.; heat is distributed by radiancy and by the convective motion of air.  
      In all cases much heat is lost along the thermal chain on account of the considerable thermal head between flame or electric resistance temperatures and ambient temperature, and especially due to lack of any real possibility of integrating the physico-mechanical structures of heating systems with the building structures to be heated, or of creating such structures which themselves can generate heat.  
      It follows that the energy utilised compared with that actually consumed is very low.  
      The present invention solves or at least greatly reduces these problems as will be explained here below.  
      Subject of the invention is a heating system for building structures and infrastructures.  
      In the walls or floor of these structures, laid side by side are one or more lengths of a strip of insulating material of a constant transversal section, in which two substantially equal cores of very high electrical conductivity, are superimposed with an insulating film in between.  
      After removing the layers of insulation from the first and second ends of said cores, their first ends are respectively connected to the two leads of a source of electric current, while their second ends are reciprocally connected by being tightly and repeatedly folded over.  
      Removal of the layers of insulating material from the ends of the two cores is facilitated by first quickly cooling them with a very cold fluid. In one type of execution, the first end of the length of strip is given a trapezoidal form ending with a rectangular extension corresponding to the lesser base of the trapezoid.  
      Said rectangular extension, with the insulating layers cleaned off, is inserted between the metal jaws of a clamp, freely sliding on the crosswise supports of a frame of insulating material and held firm by screws.  
      In this way electrical connection is established between the metal cores of the piece of strip and the conductors leading to a source of electricity, respectively connected to said jaws.  
      The clamp is inserted in a feed box which contains a transformer for supplying current of a voltage not exceeding 40 V and therefore amply within the safety limits for any person.  
      To facilitate its connection to the layers of flooring above and below, the strip may contain holes even of a considerable diameter.  
      In one type of execution a length of strip is laid in the floor of a room in a square or rectangular spiral form.  
      The first end of the piece of strip is fitted into the clamp in the electric feed box placed against one wall.  
      In the spirally laid strip there are straight lengths bent at the corners to change direction in relation to that of the piece already laid, until the centre of the room is reached and the strip is cut off.  
      The electric circuit is closed by the cut end being tightly bent back on itself, and then that of the second end of the core after removal of the layers of insulating material.  
      In another type of execution the strip is laid on the floor of a room by cutting it into lengths laid side by side and electrically connecting, in parallel or in series, the first ends of the two metal cores of each piece to pairs of electric conductors these in turn being connected, by a pair of central wires, to the feed box.  
      The electric circuit is then closed as before by tightly bending back the second end of each piece and then of the second end of the cores from which the layers of insulating material have been removed.  
      Advantageously, the cores may be of aluminium or of copper.  
      Advantageously the insulating film between the two cores is of polyester.  
      The material of the strip may preferably be of bitumen or plastic material.  
      The bitumen may be associated to a plastomer or to an elastomer.  
      Advantageously the plastic material may consist of polyester.  
      The strip may be covered with protective fabric.  
      In one advantageous type of execution the strip transmits electric power between 100 and 300 W/m 2 .  
      For laying purposes, connection between the strip and the layers on either side of it may be facilitated by the presence of holes, even of a considerable diameter, in the strip.  
      Strip dimensions are preferably as follows: overall thickness 2 mm, thickness of each metal core 0.2 mm, thickness of the layer of insulation between cores, 0.1 mm.  
      The invention offers evident advantages.  
      By placing the two metal cores one over the other, separated by a layer of insulation, electric feed can be applied to one end of the strip only by means of the clamp with two jaws respectively connected by the two conductors to the source of electric current.  
      This not only facilitates installation but drastically reduces manual labour.  
      Transformation of mains current down to a voltage not exceeding 40V eliminates any danger to users.  
      As the two conductors placed side by side through which equal and reverse current passes, creating two opposite electromagnetic fields that cancel each other out, the resulting electromagnetic field tends towards zero thus eliminating risks of atmospheric pollution.  
      The described system may be summed up as ensuring maximum simplicity of application, reducing to zero the electromagnetic field, together with diffusion of constant heat giving a high output from an extremely simple and easily operated installation. 
    
    
      Characteristics and purposes of the disclosure will be made still clearer by the following examples of its execution illustrated by diagrammatically drawn figures.  
       FIG. 1 A  roll of strip with double metal core and insulating film between them, clad with layers of insulating material, subject of the invention, perspective view with cross section shown in detail.  
       FIG. 2 A  length of strip showing the first shaped end while rapid cooling of the insulating layers at both ends is in progress to detach them from the double metal core, showing one layer at the first end already detached and ready for cutting, and with both layers detached from the second end, perspective.  
       FIG. 3 A  length of strip, the first end being inserted in a clamp for connection to the source of electric current and the second end closed in an electric circuit by repeated folds, perspective.  
       FIG. 4 A  length of strip in the form of a square spiral, fitted in the floor of a room, connected to a feed box, perspective with cross section in detail.  
       FIG. 5  Installation of lengths of strip laid side by side in the floor of a room, perspective.  
       FIG. 6 A  piece of strip with perforations, perspective.  
       FIG. 7  Enlarged cross section of a deteriorated floor where a length of perforated strip has been bonded to the glue for laying new tiles. 
    
    
       FIG. 1  shows a roll  11  of strip  10  with a pair of cores  25 ,  26  separated by a polyester film  27  and covered by layers  15 ,  16  of insulating material.  
      Layer  15  is covered with protective fabric  20 .  
       FIG. 2  shows a length  30  of the strip  10  with one end  32  given a trapezoid shape and with a rectangular extension as wide as the lesser base, while said extension is being rapidly cooled by the fluid  40  sprayed on from the container  41  to facilitate detachment of the insulating layers  15  and  16  from the metal cores  25  and  26 .  
      The layer  15  has been detached and is ready for cutting.  
      The metal cores  25 ,  26  can be seen on the end  35  having already been detached from the insulating layers  15 ,  16 .  
       FIG. 3  illustrates the length  30  with extension of the end  32 , and with the insulating layers  15 ,  16  cleaned off, inserted in a clamp  50  for connecting the metal cores  25 ,  26  to the source of electric current.  
      Said clamp comprises the base  51 , head  52  and two supports  55 , all of plastic material.  
      The first conductor jaw  60  with rearward extension  61  can freely slide through the holes  62  on the front of the supports  55 .  
      The second conductor jaw  70  can freely slide through the holes  72  on the rear extension  56  of the supports.  
      At one end the conductor jaw  60  presents a clamp  65  with screw  67  for fixing an electric cable  96  inside the transversal hole  66 .  
      At one end the second conductor jaw  70  presents a clamp  75  with screw  77  for fixing an electric cable  97  inside the transversal hole  76 . The conductor jaw  60  can be pressed up against conductor jaw  70  using the hexagonal head  81  to screw the threaded pin  80  into the threaded hole  53  in the head  52 .  
      An elastic cushion  85  is placed between the conductor jaw  70  and the base plate  51 .  
      Wires  96  and  97  connect the terminals  65  and  75  to the transformer  91  (see  FIG. 4 ) inside the feed box  90 , connected to the source of electric current by electric lines  92  and  93 .  
      As the end  32  of the piece of strip  30  has been freed of insulating layers  15 ,  16 , by tightening the conductor jaw  60  against the conductor jaw  70  using the threaded pin  80 , electric current reaches the two cores  25  and  26  through the cables  96  and  97 .  
      Repeated folding  45  and  46  of the end  35  of the piece of strip  30 , also freed of the insulating layers  15  and  16 , determines closure of the electric circuit in the second end of the two cores  25  and  26  which therefore act as electric resistances and generate heat.  
       FIG. 4  illustrates an indoor room  100  on whose floor the length  30  of the strip  10 , shown in detail in  FIG. 3 , has been laid.  
      The parallelepiped feed box  90  has been mounted in the wall  101 , said box containing the clamp  50  and above it a transformer  91  connected to the source of electric current by lines  92  and  93 , output voltage from the transformer not exceeding 40 V.  
      The length of strip  30 , bent vertically at  110 , passes through the wall  101  and enters the feed box  90  through a slit in the bottom, so that its end  32  can be inserted between the jaws  60 ,  70  ( FIG. 3 ) of the clamp  50  and the two first ends of the two cores  25  and  26  be connected to the source of electric current.  
      A polythene film  103  is placed on the ground  102  and over this a layer of polystyrene  104 .  
      On this layer  104  the length  30  of strip  10  is laid in the form of a spiral, winding towards the centre of the room with lengths placed at 90°, like  111 ,  112 ,  113 , and with turns made at each angle  115  to change direction in relation to the length just previously laid.  
      The second end of the cores  25 ,  26  makes contact, the electric circuit being then closed by the end  35  of the length  30  which is bent over repeatedly to form a block  48  as shown in  FIG. 3 .  
      A layer of cement  106  is laid over the length of spirally laid strip  30  and on top of this the flooring surface  107 .  
       FIG. 5  shows a different use made of the strip  10  in a long room  120  with walls  121 .  
      The strip  10  is here cut into lengths  123  laid parallel side by side.  
      The first ends of the cores  25 ,  26  are connected by wires  127 ,  127   1  and by the central conductor  128  to the feed box  90  this in turn being connected through the transformer  91  to electric lines  92 ,  93 .  
      The second end  126  of said lengths  123  and therefore of cores  25 ,  26  makes contact and closes the electric circuit when folded up to form the block  48  as described in  FIG. 3 .  
       FIG. 6  shows a strip with perforations  13  of a diameter even up to 10 cm.  
      These holes assist bonding to layers in either side of the strip, as shown by the example in  FIG. 7 .  
      On the deteriorated floor  130  a length  131  of strip with holes  13  is laid and over it a new floor surface of tiles  133  fixed with glue  132  that penetrates the perforations and keeps the whole stable.