Gas boiler

Abstract

Title: Gas Boiler The invention relates to a gas boiler comprising a burner (13), a heat exchanger heated by the burner (13), and a coil (3) for circulating a fluid to be heated, the coil (3) being in thermal conduction with the heat exchanger, characterized in that the heat exchanger comprises: - a hollow tube (2) extending along a longitudinal direction (d) and at least a portion of whose outer wall (24) is surrounded by the coil (3), the internal volume of the tube (2) being configured to receive air heated by the burner (13) at a first end (21) and to circulate the heated air towards a second end (22), - a plurality of plates (62, 63, 64, 65) arranged successively in the tube (2) along the longitudinal direction (d), the plates (62, 63, 64, 65) being configured to slow the flow of heated air. Figure for the abstract: Fig. 2

Description

Title of the invention: Gas boiler Technical field

[0001] The present invention relates to a gas boiler. A particular application is the production of hot water on a regular basis, for example to supply a heating circuit with hot water circulation. An industrial destination is the supply of temperature in agricultural installations, in particular in greenhouses, for nurseries. STATE OF THE ART

[0002] Flammable gases, particularly butane, have long been used to heat liquids, and water in particular. Gas boilers typically comprise a burner connected to a gas injection circuit, the burner making it possible to supply calories to a circulation circuit of a fluid to be heated, such as water. The fluid circulation circuit may in particular have the form of a coil arranged in a heating body in which the temperature rises thanks to the combustion of the gas.

[0003] Gas boilers are generally very responsive in that they allow for a rapid rise in temperature. But this comes at the cost of significant gas consumption.

[0004] There is a need to provide a gas boiler that has low gas consumption. SUMMARY

[0005] To achieve this objective, according to one embodiment, a gas boiler is provided comprising a burner, a heating body heated by the burner and a coil for circulating a fluid to be heated, the coil being in thermal conduction with the heating body, characterized in that the heating body comprises: - a hollow tube extending in a longitudinal direction and at least a portion of the external wall of which is surrounded by the coil, the internal volume of the tube being configured to receive air heated by the burner through a first end and to circulate the heated air towards a second end, - a plurality of trays arranged successively in the tube in the longitudinal direction, the trays being configured to brake the heated air.

[0006] Thanks to this arrangement, a column is created for progressive heating of the liquid, typically water, with intimate cooperation between the hollow tube and the coil which surrounds it. Inside the hollow tube, the plurality of plates makes it possible to slow down the evacuation of the heated air so as to promote thermal conduction between the tube and coil as soon as possible along the longitudinal direction of the tube. By slowing down the heated air, the heat input to the liquid circulating in the coil is significant from the base of the tube.

[0007] Surprisingly, the applicant found that it was possible, thanks to the invention, to very significantly optimize the heat input to the liquid; in particular, in practice, the air emerging from the hollow tube in the upper part is very slightly hot, which reveals that the calories have been progressively evacuated towards the coil along the tube.

[0008] Another aspect relates to an installation comprising the boiler and a liquid circulation device mounted in series with the coil so as to form a liquid circulation heating system; or the liquid may be a heat transfer fluid making it possible to exchange calories with another liquid present in a tank, for example for operation in the form of a storage water heater whose heat source is the liquid heated in the coil. The installation further comprises a gas supply source. BRIEF DESCRIPTION OF THE FIGURES

[0009] The aims, objects, as well as the characteristics and advantages of the invention will emerge more clearly from the detailed description of an embodiment thereof which is illustrated by the following accompanying drawings in which:

[0010] [Fig.l] [Fig.l] represents a side view of an embodiment of the boiler with its external casing.

[0011] [Fig.2] [Fig.2] represents a longitudinal sectional view in the mode of realization lization given in the previous figure.

[0012] [Fig.3] [Fig.3] represents an example of cooperation between a column of trays and the hollow tube.

[0013] [Fig.4] Figures 4 to 7 represent examples of usable trays.

[0014] [Fig.5]

[0015] [Fig.6]

[0016] [Fig.7]

[0017] [Fig.8] [Fig.8] shows a side view of one embodiment of a tray.

[0018] The drawings are given as examples and are not limiting of the invention. They constitute schematic representations of principle intended to facilitate the understanding of the invention and are not necessarily to the scale of practical applications. However, the illustrated shape ratios are representative of the reality of a possible embodiment. DETAILED DESCRIPTION

[0019] Before commencing a detailed review of embodiments of the invention, are listed below are optional features that may be used in combination or alternatively: • at least one plate 62,63,64,65 comprises at least one through hole; • the tube 2 and at least one plate 62,63,64,65 define an air passage around said plate 62,63,64,65; • the plurality of plates 62, 63, 64, 65 successively comprises from a first end 21 of the tube 2, a first set of at least one plate 64 having with the portion a first air passage section, and a second set of at least one plate 64 having with the portion a second air passage section, the second section being smaller than the first section; • the plurality of plates 62, 63, 64, 65 comprises a lower plate 65 at the first end 21 of the tube 2, the lower plate 65 comprising a lower face directed opposite the burner 13 and in which the lower face comprises a relief 16 projecting opposite the burner 13; • relief 16 is conical in shape; • the plates 62,63,64,65 are equidistant from each other in the longitudinal direction d; • the plates 62, 63, 64, 65 are mounted on a rod 61 extending in the longitudinal direction d; • tube 2 is circular and plates 62,63,64,65 are circular • at least one plate 62,63,64,65 has a chamfered edge 66 going in flaring towards the second end 22 of the tube 2; • the burner 13 comprises at least one pilot light; • the heating body is surrounded by a thermal insulation layer 4 itself surrounded by an external envelope 5; • a base 1 is configured to support the heating body so that the longitudinal direction d of the tube 2 is vertical.

[0020] The figures referred to in order to present preferred embodiments of the invention illustrate the gas boiler as such. The latter can, however, be integrated into a larger installation comprising firstly a gas supply source. This gas can in particular be an alkane, typically propane or butane. This source can be a cylinder or a pressurized gas tank or a shared source of the “town gas” type. The boiler allows the temperature of a liquid circulating in a coil in thermal conduction with a heating body whose temperature rises thanks to the gas. The liquid circulating in the coil can typically be water.

[0021] In one application, the liquid heated in the coil then circulates in a heating circuit, for example to provide central heating for domestic use or for industrial and agricultural use. In particular, water heated by the present boiler can circulate at nursery tables, to regulate the temperature of plants. In another application, also non-limiting, the liquid heated by the coil is used to heat another liquid, and in particular water in a tank of a water heater.

[0022] [Fig.l] provides an illustration of a possible appearance of the boiler when it is shrouded. An outer casing 5 is then visible and forms a jacket surrounding the internal components of the boiler over at least a portion thereof. In the illustration, the casing 5 has a base 51 at which a hatch 52 is arranged to provide access to the burner described later.

[0023] A column 53 surmounts the base 51 and extends in a direction corresponding to the longitudinal direction d of the tube 2 described later. The column is advantageously oriented vertically, which corresponds to the arrangement most favorable to the circulation of air by convection.

[0024] Still according to the illustration of [Fig.l], the upper end 22 of the tube 2 protrudes slightly from the column 53. Finally, a chimney 54 preferably covers the upper mouth of the tube 2.

[0025] [Fig.2] shows the internal components of the boiler. Inside the base 51 of the external casing 5, a base 1 forms the base of the boiler; it may be a plurality of feet 11 serving as support on a bearing surface of the boiler, such as the floor. However, it is not excluded that the boiler is fixed to a wall.

[0026] A base 12 is present above the feet 11 to receive a hollow tube 2. For example, the base 12 may have a female shape complementary to the external shape of the tube 2 so as to produce a fitting. Any fixing means may also be used.

[0027] A burner 13 is arranged so as to heat the hollow tube 2 and it is located in the example illustrated in the interior volume of the base. More precisely, the burner is here a pilot light (but there may be several to increase the heating power) in the gas supply circuit is not shown and is configured to heat the interior volume of the tube 2 from its lower end 21. According to one example, the flow rate of the pilot light may be less than 0.03m3 / h.

[0028] It should be noted that the use of a pilot light ensures very low gas consumption, well below the consumption of conventional central heating gas boilers. This makes it possible to form a simple and lightweight boiler applicable in situations not requiring a large volume of heated liquid.

[0029] Preferably, the flame of the burner 13 is inscribed in the longitudinal direction d of the hollow tube 2.

[0030] Preferably, the base 12 is in fluid communication with the ambient air. One solution to this end is to provide a bottom 14 under the burner 13 with ventilation elements and in particular at least one hole 15 through the bottom 14. In this way, air is admitted into the base 12 to serve as an oxidant for the combustion of the burner 13.

[0031] According to the option shown in [Fig.2], the burner 13 is arranged so that its flame is directed upwards at the base of the hollow tube 2. Typically, the tube 2 can be made of steel or aluminum. Preferably, it has a circular section. Its internal diameter is for example between 100 and 120 millimeters. Still by way of example, its length dimension can be between 1 and 1.5 meters.

[0032] It is understood that the burner 13 will heat the air entering through the base of the boiler and that this air will gradually rise towards an upper end 22 of the tube 2. Along this path, thermal conduction takes place with a coil 3 visible in [Fig.2]. Preferably, the coil is made in the form of a hollow pipe, for example made of steel or aluminum, in a helical configuration around the external wall 24 of the tube 2. Preferably, the turns which form the coil 3 are contiguous. Advantageously, the coil 3 runs through a majority of the length dimension of the tube 2, and preferably at least 80% of this dimension. The coil 3 has an inlet mouth 31, at the lower end of the coil 3, which can be connected to a circuit for supplying the liquid to be heated.It also has an outlet mouth 32, at the upper end of the coil 3, which can be connected to a circuit for discharging the heated liquid.

[0033] The angle formed by the helix of the coil 3 relative to the longitudinal direction d of the tube 2 is for example greater than or equal to 5° and / or less than or equal to 20°. Advantageously, the coil 3 ensures a relatively slow progression of the liquid along the tube 2 to allow a certain heat exchange time.

[0034] Between the coil 3 and the casing 5, a thermal insulation layer 4 provides insulation. This may be a filling with insulating foam.

[0035] We will now describe more precisely the succession of plates present in the hollow tube: referring in particular to [Fig. 3], we see that the plates 62, 63, 64, 65 follow one another in the longitudinal direction d. Their presence ensures a pressure drop making it possible to slow down the rise of the heated air. Thanks to this slowing down, there is more time for thermal conduction heating the liquid in the coil 3.

[0036] Advantageously, as illustrated, the plates 62, 63, 64, 65 follow one another with the same spacing from one another along the longitudinal axis d; for example, they can be equidistant by a distance of between 80 and 100 millimeters.

[0037] Preferably, the external shape of the plates 62, 63, 64, 65 is homothetic relative to the internal shape of the tube 2. In the preferred case of a tube 2 of circular section, the plates are preferably also of circular section.

[0038] Advantageously, the plates extend perpendicular to the longitudinal direction d.

[0039] According to one possibility, at least some trays have holes passing through them so as to allow air to pass from an upstream part to a downstream part of said tray in the longitudinal direction d. According to an additional possibility, the holes of a tray have the same diameter. They can be regularly distributed on the tray, so as to define identical angular sectors. Such arrangements contribute to a regular flow of air, but the latter is slowed down by the tray.

[0040] In the example of [Fig. 5], representing a plate 65, eight holes are present. Plate 65 is, in this case, the first plate arranged above the burner 13. Plate 62 is another perforated plate, a top view of which is provided in [Fig. 6]. Plate 62 has five holes in this example. According to one example, plate 62 is located midway between plate 65 and a plate 63 forming the last plate along the tube 2. [Fig. 7] provides an example for plate 63. In this case, it has four holes. In the representations given in the figures, it is noted that the holes of the different plates 65, 62, 63 have the same diameter. In this context, by modulating the number of holes, the air passage section through the plates is modified.

[0041] According to one possibility, it is arranged so that the plates having holes have air passage sections which strictly decrease towards the upper end of the tube 2. Thus, the braking of the air is increased towards this end.

[0042] According to one possibility, at least some plates have an external diameter equal to the internal diameter of the hollow tube 2. This may be the case for plates having holes. Thus, in the example corresponding to the figures, the diameters d2, d3 and d4 are identical to the internal diameter d0 of the tube 2. The same may be true of the diameter d1 of the plate constituting the bottom 14.

[0043] According to one possibility, at least some plates have an external diameter smaller than the diameter dO of the tube 2. This arrangement makes it possible to preserve an air passage between the external edge of such a plate and the internal wall 23 of the tube 2. In the example shown, it is typically the plates 64 which correspond to this configuration. Non-limitingly, in the example illustrated, the plate 64 does not have holes.

[0044] It is understood that other arrangements allowing a peripheral passage to be preserved around a tray are possible; for example, the tray may have a lateral excavation, for example formed by a plate on its edge.

[0045] According to one example, the plates 64 preserving a peripheral air passage have a diameter d5 (or d6) such that each plate 64 defines an air passage with a width greater than or equal to 10 mm and / or less than or equal to 30 mm. According to one possibility, the diameter d5 of at least one plate is at least 10% less than the diameter d0.

[0046] It is also possible to play on the peripheral passage section around the plates, or some of them, to modulate the braking of the air. In particular, for the plates having such a peripheral passage, it is possible to ensure that the section of these peripheral passages never increases towards the upper end of the tube 2. Thus, this peripheral passage section can be identical between two such successive plates and / or decrease between two such successive plates.

[0047] [Fig. 2] provides an example in which the plates 64 having such peripheral passages are organized in two stages. A first stage, corresponding to a lower set of plates 64, has a diameter d5 less than d0. A second stage, corresponding to an upper set of plates 64, has a diameter d6 strictly greater than d5. For example, d6 is between 5 and 8% larger than d5.

[0048] It is understood that the change of stage causes the air to enter a section of the length of the tube 2 in which it will be less able to pass into the peripheral passages.

[0049] According to one possibility, the number of plates in each stage is identical. According to another possibility, the plates 64 having a peripheral passage are more numerous than the perforated plates. Also, in one configuration, the plates 64 having a peripheral passage do not have holes. In this way, it is possible to promote a flow of air towards the internal wall 23 of the tube 2 to optimize the thermal conduction through the tube 2.

[0050] The representation given in Figures 2 and 3 alternates perforated plates and plates with peripheral air passage. In this example, the lower plate 65 is followed by a series of plates 64 with a diameter d5 (here six plates; but this number can vary). The series of plates 64 is itself followed by a perforated bearing plate 62 followed by another series of plates 64 with a diameter d6. The column of a plurality of plates ends in this example with an upper plate 63.

[0051] [Fig. 8] provides an embodiment applicable to all or part of the plates 62, 63, 64, 65, and particularly to the plates 64, in which the edge 66 of the plate is chamfered so as to produce a flaring of the diameter of the plate from a lower face 661 towards an upper face 662 of said plate, the upper face being directed further downstream in the direction of evolution of the heated air. In the case of plates 64 chamfered, the dimensions d5 and d6 given in the figures corresponding to the maximum diameter of the chamfered edge. The chamfered edge preserves a peripheral air passage; the chamfered shape tends to slow down the air and disrupt its flow to promote thermal exchanges.

[0052] According to one example, it is the non-perforated plates which comprise such a chamfer.

[0053] In the preceding descriptions concerning the external dimensions of the plates, and typically their diameter when they have a circular section, it is understood that the dimensions discussed correspond to the largest external dimension of a plate. In the case of a circular plate, the diameters corresponding to d1, d2, d3, d4, d5 and d6 are taken at the level of the upper face 662 of the plate considered.

[0054] Different means can be envisaged for positioning the plates 62, 63, 64, 65 in the hollow tube 2. Those illustrated use a rod 61 extending in the longitudinal direction d between a lower end 611 and an upper end 612. The plates each have a central hole allowing them to be fixed along the rod 61. For example, the rod 61 is a threaded rod and each plate is held by at least one nut (preferably by two nuts on either side of the plate) on the rod. According to our example, the central hole of each plate is itself threaded so as to cooperate in the form of a helical slide with the rod 61. According to another possibility, also non-limiting, the plates are welded along the rod 61. According to one aspect, the rod is made of steel or aluminum. It is preferably made of a material that is a good thermal conductor.

[0055] Still with a view to improving heat recovery, one embodiment comprises a relief 16 arranged projecting from the lower face of the first plate 65, so as to face the flame coming from the burner 13. For example, the flame is not more than 10 mm from the tip of this relief 16. The latter advantageously has a conical shape so as to have a section gradually widening in the direction of the plate.

[0056] The relief 16 is preferably a solid member, advantageously made of steel, so as to be relatively massive. It can thus accumulate heat and transmit it to the column of plates, starting with the first plate 65. The base of the relief 16 can extend over at least 30% of the surface area of ​​the lower face of the plate 65.

[0057] According to an advantageous possibility, it is easy to disassemble the boiler proposed here. In particular, the plurality of plates 62, 63, 64, 65 can be extracted by removing the rod 61 through the upper end of the hollow tube 2. Replacing is carried out in the reverse direction. Any arrangement allowing this assembly to be fixed in the hollow tube is conceivable. According to one example, the lower plate 65 comes to bear on a stop (not shown) on a surface peripheral to the internal wall 24 of the tube 2 so as to immobilize the column of trays.

[0058] The invention is not limited to the embodiments previously described and extends to all embodiments covered by the invention.

[0059] Numerical references 1. Base 11. Foot 12. Base 13. Burner 14. Background 15. Bottom hole 16. Relief 2. Hollow tube 21. Lower end 22. Upper end 23. Internal wall 24. External wall 3. Fluid circuit coil 31. Intake mouth 32. Outlet mouthpiece 4. Thermal insulation layer 5. Outer envelope 51. Base 52. Trapdoor 53. Column 54. Chimney 6. Column 61. Stem 611. Lower end 612. Upper end 62. Bearing plate 63. Upper shelf 64. Intermediate plateau 65. Lower shelf 66. Chamfered edge 661. Underside 662. Upper face d. Longitudinal direction

Claims

Claims

1. Gas boiler comprising a burner (13), a heating body heated by the burner (13) and a coil (3) for circulating a fluid to be heated, the coil (3) being in thermal conduction with the heating body, in which the heating body comprises a hollow tube (2) extending in a longitudinal direction (d) and at least a portion of the external wall (24) of which is surrounded by the coil (3), the internal volume of the tube (2) being configured to receive air heated by the burner (13) via a first end (21) and to circulate the heated air towards a second end (22), characterized in that the heating body further comprises a plurality of plates (62, 63, 64, 65) arranged successively in the tube (2) in the longitudinal direction (d), the plates (62, 63, 64, 65) being configured to brake the heated air, at least one plate (62,63,64,65) comprising at least one through hole for air passage.

2. Boiler according to the preceding claim, in which the tube (2) and at least one plate (62,63,64,65) define an air passage around said plate (62,63,64,65).

3. Boiler according to the preceding claim, in which the plurality of plates (62, 63, 64, 65) successively comprises from a first end (21) of the tube (2), a first set of at least one plate (64) having with the portion a first air passage section, and a second set of at least one plate (64) having with the portion a second air passage section, the second section being smaller than the first section.

4. A boiler according to any preceding claim, wherein the plurality of trays (62,63,64,65) comprises a lower tray (65) at the first end (21) of the tube (2), the lower tray (65) comprising a lower face facing the burner (13) and wherein the lower face comprises a relief (16) projecting opposite the burner (13).

5. Boiler according to the preceding claim, in which the relief (16) is conical in shape.

6. Boiler according to any one of the preceding claims, in which the plates (62,63,64,65) are equidistant from each other in the longitudinal direction (d).

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12. Boiler according to any one of the preceding claims, in which the plates (62,63,64,65) are mounted on a rod (61) extending in the longitudinal direction (d). Boiler according to any one of the preceding claims, in which the tube (2) is circular and in which the plates (62,63,64,65) are circular. Boiler according to the preceding claim, in which at least one plate (62,63,64,65) has a chamfered edge (66) widening towards the second end (22) of the tube (2). Boiler according to any one of the preceding claims, in which the burner (13) comprises at least one pilot light. Boiler according to any one of the preceding claims, in which the heating body is surrounded by a layer of thermal insulation (4) itself surrounded by an external casing (5). Boiler according to any one of the preceding claims, comprising a base (1) configured to support the heating body so that the longitudinal direction (d) of the tube (2) is vertical.

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