Abstract:
An electric heating apparatus heats a circulating fluid for a basin or pool. A section of a duct is connected, at its upstream end, to an intake duct for the fluid. Its downstream end is connected to a duct for the discharge of that fluid, this forming an end-to-end series for conducting the fluid. The apparatus includes a plurality of heating elements elongated in the direction of the elongation of the duct. The heating unit includes the heating element mounted on an elongated base and approximately parallel with the longitudinal dimension of said base. The heating unit is mounted on the duct in such a manner that the base closes an opening which is provided to facilitate the assembling of the heating unit on the duct. The heating elements are supported by a support that is movably mounted inside an opening in the base.

Description:
BACKGROUND 
     The present invention relates to an electric heating apparatus meant for heating a fluid in circulation and more especially for the heating of water in a basin or a pool, etc. 
     An electric heating installation meant for a pool generally comprises an electric heating apparatus, a system of pipes starting from the basin for transporting the fluid to be heated toward the heating apparatus, and the heated fluid from the heating apparatus toward the basin. A circulation pump mounted in series in the piping system makes possible the circulation of the fluid to be heated. 
     The patent document FR-A-2 621 992 describes an electric heating apparatus for a fluid in circulation, especially for the water of a pool. This apparatus comprises a U-shaped tube provided so that it can be connected, by its upstream end, to a fluid intake duct and, by its downstream end, to a fluid discharge duct. The upper parts of the two arms are T-shaped, the T(s) receiving an elongated heating element, such as immersible heaters, that are placed approximately in the axis of the ducts that form the legs of the U. 
     This heating apparatus gives full satisfaction, but it nevertheless has a certain number of drawbacks: its structure is relatively fragile and complex, this increasing its cost of fabrication. Also, it is not very compact, and therefore relatively difficult to install. 
     Attempts have been made to remedy these drawbacks by providing a heating apparatus of the type that comprises a piping section provided to be connected to a fluid intake duct and to a fluid discharge duct, said apparatus also comprising a heating unit fixed inside said section and in the longitudinal axis of the latter. This heating unit is made up of a metallic plate under which there is set, by means of threaded sockets, a heating element of the coil type. Such an apparatus is described in the American patent document U.S. Pat. No. 4,924,069. 
     A major drawback of this plate is found in the fact that in order to proceed to the replacement of the heating element it is necessary, each time, to remove from under the place the sockets for the fixation of that heating element. 
     SUMMARY 
     The purpose of the present invention is to offer an electric heating apparatus for a fluid, of the aforementioned type, the structure of which is such that the heating element is easily exchangeable. 
     To that end, such a heating apparatus for a fluid in circulation, and more especially for the water in pools, comprises a section of pipe provided so that it can be connected, by its upstream end, to a intake duct of that fluid and, by its downstream end, to a discharge duct for this fluid, said apparatus further comprising an elongated heating element (located) approximately in the axis of this section of duct, and a heating unit made up of an elongated base on which this heating element is mounted in projection, the axis of this heating element being approximately parallel to the longitudinal dimension of the mentioned base, this heating unit being mounted on the above-mentioned section of duct in such manner that the above base closes a port provided to permit the passage of the above heating element when this heating unit being mounted on that section of duct. 
     This heating apparatus is characterized in that the above heating element is supported on a support, which is mounted movable inside an opening of the above-mentioned base. 
     According to another characteristic of the invention, this heating element is constituted by a plurality of immersible heaters. 
     According to another characteristic of the invention the above-mentioned base carries a unit for the governing and the regulating of the heating element. 
     According to another characteristic of the invention this base is equipped with a rate of water flow sensor that projects on the side of the heating element, this sensor being located upstream from the heating element inside the above-mentioned section of duct. 
     According to another characteristic of the invention, the above-mentioned heating apparatus is connected to intake and discharge ducts, by locking and unlocking means. 
     The above-mentioned characteristics of the invention, as well as others, will appear more clearly upon reading of the following description of one example of execution, this description being given relative to the attached drawing in which: 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a view in section along a median longitudinal plane of an apparatus according to the invention, the section of duct of this apparatus and its heating unit being shown in exploded view. 
     FIG. 2 is a partial section in exploded view of the support of the heating element for the apparatus according to the invention. 
     FIG. 3 is a section view, along III--III in FIG. 1, of a means to maintain the spacing between the different parts of the heating element. 
     FIG. 4 is a view from the top of a section of the duct that constitutes one element of an apparatus according to the invention, and 
     FIG. 5 is a section view along a median longitudinal plane, of a second mode of execution of an apparatus according to the present invention, the section of duct of this apparatus, the heating unit and its lid being shown in exploded view. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     In the example of execution in FIG. 1, the heating apparatus according to the invention is made up of a heating unit 20 mounted on a section of duct 10. 
     The heating unit 20 is made up of a base 21 that comprises a seat or subbase 21a approximately rectangular in shape, equipped, on its lower surface, with a centering member. This latter is oblong in shape and it has rounded ends that form a half-circle. The base 21 is pierced with a perforation 21b into which there is fitted and set a cylindrical support 22 for the heating element, which element is made up, here, of two rows of three immersible heaters 23a, 23b, 23ac each, (the second row of immersible heaters being placed symmetrically to the first one, relative to the section plane in FIG. 1, it is not shown). 
     According to a characteristic of the invention, the duct that forms the envelope of each immersible heater is made of titanium or of a material known under the trade name of Incoloy. 
     There is shown in FIG. 2 an exploded which of the support 22 for the immersible heaters 23a, 23b, and 23c. 
     This support 22 comprises, in its lower part, a flange 22d provided to ensure the tightness of the section 10 of duct, when the heating unit 20 is installed inside said section 10 of duct. The flange 22d ends with a collar 22e in its upper part, that is provided to rest on a shoulder 21c arranged inside the perforation 21b of the base 21. The material of the flange 22d advantageously is an elastomer such as a terpolymer of ethylene, of propylene and of diene (this material is known by the acronym EPDM). 
     Longitudinal perforations 22f traverse the flange 22d through and through, and they are provided to lodge the ends of cables 29a, 29b, and 29c that respectively are soldered to the electric terminals of resistances 23 of the immersible heaters 23a, 23b and 23c, so as to feed current to the latter. In practice, as shown in the part of FIG. 2 that is a section view, once the soldering points 22g have been executed, the above ends of cables 29a, 29b and 29c and of the resistances 23 are covered by compound-filling, with a sheath 22h made up of a hard insulating material, such as hypalon. The diameter of each sheath 22h is such that the latter is mounted by force into the perforations 22f. 
     Support 22 comprises a plate or shield 22a provided to cap the collar 22e of the flange 22d. For the assembling of the flange 22d onto the base 21, stirrups 22c take their support on the one part on the base 21 itself and, on the other part, on the plate or shield 22a, and they are tightened by means of crews screwed into the base 21. 
     The plate or shield 22a is equipped with openings 22aa having the same diameter as the above-mentioned perforations 22f, that are provided for the lodging of the above sheaths 22g. The plate or shield 22a has a curved-in edge 22ab that is provided so that it will practically fit against the edge 22ea of the collar 22e. Preferably this plate or shield 22a is made of zinc-coated steel. 
     It is easy to understand that the elasticity of the material forming the flange 22d makes it possible to ensure tightness, on the one part along the aforementioned collar 22e, because the latter is tightened by the plate or shield 22a and, on the other part, between the external surfaces of the sheaths 22g and the surfaces of the perforations 22f. It will moreover, be noted that the aforementioned screwing of the plate or shield 22a onto the base 21 allows for a distribution of the tightening force over the entirety of the upper surface of the collar 22e, this further improving the tightness of the section 10 of duct. 
     As it may be seen in FIG. 1, each immersible heater 23a, 23b, or 23c, following a short section that comes out of the flange 22d, forms a 90° elbow and is extended by a long linear section. The linear sections of the immersible heaters 23a, 23b, 23c are joined together by a means 23d that maintains their spacing, and shown in detail in FIG. 3, and they extend approximately parallel to the longitudinal direction of base 21. Besides, they belong to a same plan perpendicular to the seat or subbase 21a and they end beyond the ends of that seat or subbase 21a. 
     Said means 23d for maintaining the spacing between the immersible heaters 23a, 23b and 23c is made up of a crosspiece that is mounted between the two rows of immersible heaters 23a, 23b, and 23c, in a position perpendicular to the planes that respectively contain the two rows. The crosspiece 23d comprises, in each one of its sides provided to be applied against one of the above-mentioned rows, concavities 23da provided to hold the immersible heaters 23a, 23b and 23c of the mentioned row. Each concavity 23da is equipped with small peaks 23db in the shape of a truncated cone, that are provided to immobilize the corresponding immersible heaters 23a, 23b or 23c. The two aforementioned lodging alignments are connected between themselves by several sections 23dc of parallel shafts, so that the crosspiece 23d has a shape that is approximately rectangular and is non-deformable. 
     It will be noted that the very much cut-out shape of the crosspiece 23d makes it possible to prevent its forming an obstacle to the flowing of the fluid through the section 10 of duct, something that would cause too important losses of pressure. 
     The section 10 of duct, seen from the top in FIG. 4, is constituted by a linear duct, having a circular section for example, and it is arranged so that it can be connected, by its upstream end, to a duct 12a that feeds the fluid and, by its downstream end, to a duct 12b that discharges the fluid. The section 10 of duct being rectilinear, the ducts 12a and 12b of necessity have coaxial ends. Screwing rings 11a and 11b ensure the maintaining of the connection while ring joints 13a and 13b ensure its tightness. In normal functioning, the fluid runs through the section 10 of duct as shown by the arrow A. 
     It will be noted that the rings 11a and 11b respectively are mounted on the ducts 12a and 12b and that after unscrewing, they release the section 10 of duct that than then be easily removed. 
     It will be noted that the section 10 of duct could also be assembled on the upstream and downstream ducts 12a and 12b by any suitable means, by gluing for example. 
     Advantageously, the section 10 of duct is made up of polyvinyl chloride. 
     The section 10 of duct has, in its upper part, a longitudinal horizontal plate 10b the upper surface of which is flat and that is pierced, through and through, with an oblong perforation 10a the ends of which are rounded in semi-circle. The dimensions of the opening 10a are equal, play taken into account, to the dimensions of the seat or subbase 21a of the base 21 of the unit 20. 
     When the heating unit 20 is mounted on the section 10 of duct, the lower surface of the seat or subbase 21a of the unit rests on the upper surface of the plate 10b of the section 10 of duct, and the centering member of seat 21a of the unit 20, is lodged inside the opening 10a of the section 10 of duct. The centering member of 21a ensures the centering of the unit 20 on the section 10 of duct. 
     As it may be seen in FIG. 4, threaded blind holes 10c are pieced on the upper surface of the plate 10b, along its periphery, and they can receive blocking screws (not shown) that ensure the fixation of the unit 20 on the section 10 of duct. 
     For the assembling of the unit 20 onto the section 10 of duct, this unit 20 is placed so that the linear parts of the immersible heaters 23a, 23b and 23c will be slightly slanted relative to the axis of the section 10 of duct, then the free ends of the immersible heaters 23a, 23b and 23c are made to penetrate inside the section 10 of duct. Then, while these ends are being moved toward the downstream end of the section 10 of duct, the slanting of the unit 20 is reduced up to the point at which it is possible to introduce its centering member into the opening 10a. Finally unit 20 is fixed onto the section 10 of duct. 
     It will be noted that during functioning, the immersible heaters 23a, 23b and 23c are located appreciably in the axis of the section 10 of duct, and they are then immersed in the heat-exchanging fluid that runs through the section 10 of duct. Thus they find themselves parallel with the direction of flow of the fluid, something that improves the thermal exchange between them and the fluid. 
     The slanted insertion of the immersible heaters 23a, 23b and 23c into the section 10 of duct, such as just explained, makes possible the use of immersible heaters that are longer than the base 21, as seen in FIG. 1. 
     In order to replace the immersible heaters 23a, 23b and 23c for other immersible heaters of a different power for example, the unit 20 is disassembled from the section 10 of duct, by executing in reverse order the above-described operations, then the support 22 is separated from the base 21. It is then possible to execute the replacement of immersible heaters, and then again to fix the assembly onto the section 10 of duct. The movable assembling of support 22 on the base 21 thus facilitates the interchangeability of the heating elements 23a, 23b and 23c. 
     In the second example of execution of a heating apparatus according to the invention, (see FIG. 5), the heating unit 20 described above is mounted in identical manner on the section 10 of duct. The heating apparatus, however, comprises the following additional characteristics. 
     The immersible heaters 23a, 23b and 23c respectively are connected to the outputs of a governing and regulating unit 24 that is connected, on the upper face of the unit 20, by means of wires 29a, 29b and 29c. The unit 24 is connected to two regulating thermostats 25a and 25b, to a terminal box 26, and to a water rate of flow sensor 27. All of this equipment is lodged inside a casing closed at its upper part by a lid 30. The thermostats 25a and 25b are equipped with temperature sensors (not shown), the glove fingers of which are located inside the support 22. 
     The thermostats 25a, and 25b and their respective buttons 25aa and 25bab are placed on each side of one of the end walls 21c of the casing. They are respectively connected, by wires 24a and 24b, to adequate inputs of the unit 24 and they make it possible for the user to set the set values that regulate the water temperature. 
     The unit 24 is fed the line current via a wire 24c, a terminal box 26 affixed onto an end wall of the casing, and a wire 26a. 
     The sensor 27 is affixed to the seat or subbase 21a in such manner that it is submerged in the liquid running through the section 10 of duct, upstream from the immersion heaters 23a, 23b and 23c. It is connected to the casing 23 by means of a wire 24d. 
     The seat or subbase 21a is longitudinally equipped with two walls 21e of which only the first one is visible in FIG. 3. Each one of them has a curved-profile shape that takes on the complementary shape of the side 30b of lid 30. 
     It will be noted that the shape of lid 30, as well as the shape of the walls 21e is not functional, but only aesthetic. 
     During the setting into place of the lid, the rectangular plane 30a of this lid 30 is positioned, at its ends, on the summit edges of the two walls 21e. It is immobilized by screws (not shown). Only the two buttons 25aa and 25ba and the feed wire 26a remain visible externally to the base 21a (sic), in a space above its seat or subbase 21a.