EP0097905A2 - Water-air convector with chimney effect for space-heating, and method of producing such a convector - Google Patents

Abstract

A heat exchanger consists of concentric sleeves (M1, M2), each formed by three helical turns of a tube (T1) equipped with two vertical and longitudinal fins (A1, B1), and made from a plastic containing a thermally conductive filler, this sleeve being formed by extruding the tube with its fins, and then bending. <IMAGE>

Description

The invention relates to a water-air convector with a chimney effect for heating a room. It further extends to a method of manufacturing such a convector.

It is known that the so-called "central heating" installations for space heating comprise, in each room, a heat exchanger of the radiator or convector type, the convector being, relative to the radiator, characterized in that almost all of the heat is removed to the room by air convection.

It is known to produce water-air convectors using steel sheets constituting on the one hand pipes for hot water on the other hand fins which are heated by these pipes by thermal conduction in the metal and which efficiently transmit heat to the air thanks to their large contact surface with it. It is also known that this heat transmission is made more active by virtue of the rising speed of the air heated up in contact with these fins, and that this speed can be increased by chimney effect, that is to say by channeling the air in a vertical chimney around and above the fins.

• - des conduites d'eau chaude,
• - des surfaces d'échange thermique en contact thermique avec ces conduites
• - et une cheminée dont les parois sont disposées sensiblement verticalement autour et au-dessus de ces surfaces d'échange thermique pour canaliser et accélérer la circulation ascensionnelle de l'air échauffé au contact de ces surfaces, de manière à accélérer l'échange thermique entre ces surfaces et l'air circulant à leur contact, ce convecteur connu étant caractérisé par le fait que ces conduites et ces surfaces d'échange thermique sont constituées par des plaques à canaux internes, le matériau de ces plaques étant un haut polymère organique extrudable comportant une charge thermiquement conductrice.

These conventional convectors have the disadvantage of being relatively expensive, because their manufacture requires a high expenditure of energy, numerous welds, folds, assemblies etc ... and to require a certain maintenance (painting) to protect them against rust, this is why, in document FR-A No. 2,478,277, a water-air convector with chimney effect has been proposed, comprising:

• - hot water pipes,
• - heat exchange surfaces in thermal contact with these pipes
• - And a chimney whose walls are arranged substantially vertically around and above these heat exchange surfaces to channel and accelerate the upward circulation of the heated air in contact with these surfaces, so as to accelerate the heat exchange between these surfaces and the air flowing in contact with them, this known convector being characterized by the fact that these pipes and these heat exchange surfaces consist of plates with internal channels, the material of these plates being a high extrudable organic polymer comprising a thermally conductive filler.

These internal channel plates can be in the form of vertical plates, the channels of which are horizontal and protrude on both sides of the plate. The arrangement using channels makes it possible to have a sufficient water speed for good heat exchange with the water. Its realization is quite easy. The fact that the channels are horizontal tends to cause the boundary layer to become detached each time the ascending air passes through a channel.

However, it appeared that the cost of the convector could be lowered further.

The object of the present invention is to further increase the ease of making a water-air convector with a chimney effect for heating a room, while retaining good heat transfer efficiency, and without requiring any particular maintenance of the convector.

• - une succession de panneaux chauffants verticaux parallèles laissant circuler entre eux des lames d'air ascendant, ces panneaux s'étendant selon une direction horizontale longitudinale, se succédant selon une direction horizontale transversale, étant constitués d'un haut polymère organique extrudable muni d'une charge thermiquement conductrice, et comportant chacun
• - des surfaces d'échange thermique verticales,
• - une succession verticale de tubes longitudinaux parcourus par de l'eau chaude, formés par des parois en continuité de matériau avec ces surfaces d'échange en formant saillie sur ces surfaces,
• - et une cheminée dont les parois sont disposées sensiblement verticalement autour et au-dessus de ces surfaces d'échange thermique pour canaliser et accélérer la circulation ascensionnelle de l'air échauffé au contact de ces surfaces, de manière à augmenter l'échange thermique entre ces surfaces et l'air circulant à leur contact,
• - ce convecteur étant caractérisé par le fait que lesdits tubes et surfaces d'échange thermique sont constitués par des manchons présentant chacun une paroi avant et une paroi arrière verticales longitudinales constituant lesdits panneaux, et deux parois latérales verticales incurvées raccordant ces parois avant et arrière, ces manchons s'entourant les uns les autres en formant une succession radiale à partir d'un volume central
• - chacun de ces manchons étant constitué par un tube portant des ailettes et enroulé en hélice et faisant plusieurs fois le tour du manchon et en montant d'un étage à chaque tour, ces ailettes étant verticales, s'étendant toutes deux selon la longueur de ce tube, et étant au nombre de deux, l'une en position supérieure, l'autre en position inférieure, ces deux ailettes occupant au moins 80% de l'intervalle vertical entre deux sections du même tube à deux étages adjacents, de manière à copstituer lesdites surfaces d'échange thermique sous la forme d'une paroi verticale sensiblement continue.

Its purpose is a water-air convector with a chimney effect to heat a room, this convector comprising:

• - a succession of parallel vertical heating panels allowing ascending air spaces to circulate between them, these panels extending in a longitudinal horizontal direction, succeeding in a horizontal transverse direction, being made of a high extrudable organic polymer provided with a thermally conductive filler, and each comprising
• - vertical heat exchange surfaces,
• a vertical succession of longitudinal tubes traversed by hot water, formed by walls in continuity of material with these exchange surfaces by forming a projection on these surfaces,
• - And a chimney whose walls are arranged substantially vertically around and above these heat exchange surfaces to channel and accelerate the upward circulation of the heated air in contact with these surfaces, so as to increase the heat exchange between these surfaces and the air circulating in contact with them,
• - This convector being characterized in that said tubes and heat exchange surfaces consist of sleeves each having a longitudinal vertical front wall and rear wall constituting said panels, and two curved vertical side walls connecting these front and rear walls, these sleeves surrounding each other forming a radial succession from a central volume
• each of these sleeves being constituted by a tube carrying fins and wound in a helix and making several turns around the sleeve and going up one stage at each turn, these fins being vertical, both extending along the length of this tube, and being two in number, one in the upper position, the other in the lower position, these two fins occupying at least 80% of the vertical interval between two sections of the same tube with two adjacent stages, so co-constituting said heat exchange surfaces in the form of a substantially continuous vertical wall.

• - les deux ailettes du tube sont, l'une large et l'autre étroite, les manchons successifs étant alternativement constitués par un tube dont l'ailette étroite est, en position inférieure et en position supérieure, de manière à permettre à la fois de décaler verticalement les tubes des manchons successifs pour éviter un rétrécissement excessif de la lame d'air ascendant, et de supporter les parties inférieures de ces manchons successifs sur un même support s'étendant horizontalement à partir du volume central. L'épaisseur des ailettes est de préférence sensiblement égale à celle de la paroi du tube.

In addition, preferably according to the circumstances, the following provisions are adopted:

• - the two fins of the tube are, one wide and the other narrow, the successive sleeves being alternately constituted by a tube whose narrow fin is in the lower position and in the upper position, so as to allow both vertically offset the tubes of the successive sleeves to avoid excessive narrowing of the rising air knife, and to support the lower parts of these successive sleeves on the same support extending horizontally from the central volume. The thickness of the fins is preferably substantially equal to that of the wall of the tube.

The present invention also relates to a method of manufacturing a convector, this method being characterized in that the tube is manufactured continuously with its fins by a single extrusion operation, then sectioned into sections, then bent hot to form the sleeves.

• La figure 1 représente une vue d'ensemble en perspective d'un convecteur selon l'invention.
• La figure 2 représente une vue en perspective coupée de ce eonveo- teur sans son boîtier formant cheminée.
• La figure 3 représente une vue en coupe de plusieurs manchons de ce convecteur.
• La figure 4 représente une vue en perspective à échelle agrandie de l'une des entretoises verticales équidistantes constituant des espaceurs pour la circulation de l'air entre les manchons successifs de ce convecteur.

Using the attached diagrammatic figures, a description will be given below, without implied limitation, of how the invention can be implemented. It should be understood that the elements described and shown can, without departing from the scope of the invention, be replaced by other elements performing the same technical functions. When the same element is represented in several figures, it is designated therein by the same reference sign.

• FIG. 1 represents an overall perspective view of a convector according to the invention.
• FIG. 2 represents a cut view in perspective of this unveiler without its casing forming a chimney.
• Figure 3 shows a sectional view of several sleeves of this convector.
• FIG. 4 represents a perspective view on an enlarged scale of one of the equidistant vertical spacers constituting spacers for the circulation of air between the successive sleeves of this convector.

The convector which is shown in FIG. 1 comprises a rectangular box 1 with vertical walls carried by four feet 2 and constituting a chimney 4 with rectangular section 20 cm wide and 75 cm high provided with a perforated cover 6.

In the chimney, at the bottom thereof, are arranged nine concentric vertical sleeves constituting a heat exchanger 8 supplied with hot water by a high inlet 10, the outlet 12 being at the bottom.

The distribution of the hot water flow in parallel in the nine vertical sleeves is carried out in an inlet manifold 20 located at the upper part of the heat exchanger, supplied by the high inlet 10.

Similarly, an outlet manifold 22 located at the bottom of the heat exchanger groups the water flows in parallel from the nine vertical sleeves, discharged through outlet 12.

The air circulation is represented by the arrows 16. It starts from the perforated bottom 14 of the housing. the air heated by the exchanger rises in the chimney and exits through the cover 6.

The material of this exchanger can be a mixture of high density polyethylene with 40% by weight of chlorinated polyethylene, the latter comprising 35% of chlorine by weight with 2 to 2.5% of a conventional antioxidant agent (mixture of alkylated polyphenols and of thiodipropionates) and a conventional coupling agent (1% of an organic titanate). Load consists of 80% by weight of a mixture of carbon black with 10% of carbon fibers from 1 to 3 mm long for a diameter. of 8 micrometers. Such a material can be shaped by extrusion and subsequently receive limited deformations when hot.

• - une succession de panneaux chauffants verticaux parallèles laissant circuler entre eux des lames d'air ascendant, ces panneaux s'étendant selon une direction horizontale longitudinale, se succédant selon une direction horizontale transversale, étant constitués d'un haut polymère organique extrudable muni d'une charge thermiquement conductrice, et comportant chacun :
• - des surfaces d'échange thermique verticales,
• - une succession verticale de tubes longitudinaux parcourus par de l'eau chaude, formés par des parois en continuité de matériau avec ces surfaces d'échange en formant saillie sur ces surfaces,
• - et une cheminée dont les parois sont disposées sensiblement verticalement autour et au-dessus de ces surfaces d'échange thermique pour canaliser et accélérer la circulation ascensionnelle de l'air échauffé au contact de ces surfaces, de manière à augmenter l'échange thermique entre ces surfaces et l'air circulant à leur contact.

The heat exchanger 8 comprises as known:

• - a succession of parallel vertical heating panels allowing ascending air spaces to circulate between them, these panels extending in a longitudinal horizontal direction, succeeding in a horizontal transverse direction, being made of a high extrudable organic polymer provided with a thermally conductive filler, and each comprising:
• - vertical heat exchange surfaces,
• a vertical succession of longitudinal tubes traversed by hot water, formed by walls in continuity of material with these exchange surfaces by forming a projection on these surfaces,
• - And a chimney whose walls are arranged substantially vertically around and above these heat exchange surfaces to channel and accelerate the upward circulation of the heated air in contact with these surfaces, so as to increase the heat exchange between these surfaces and the air flowing in contact with them.

According to the invention and as shown in Figures 2 and 3, said tubes and heat exchange surfaces are constituted by sleeves each having a front wall and a longitudinal vertical rear wall constituting said panels, and two curved vertical side walls connecting these front and rear walls, these sleeves surrounding each other by forming a radial succession from a central volume - each of these sleeves being constituted by a tube (T1, T2) carrying fins and wound in a helix and making several times around the sleeve and going up one stage at each turn, these fins being vertical both extending along the length of this tube, and being two in number one in the upper position (B1, B2) , the other in the lower position (A1, B2) these two fins occupying at least 80% of the vertical interval between two sections (Tla, T1b) of the same tube (T1) with two adjacent stages, so as to constitute said surfaces. these heat exchange in the form of a substantially continuous vertical wall.

Preferably, the two fins of the tube (T1, T2) are, one wide (B1, B2) and the other narrow (A1, A2), the successive sleeves (M1, M2) being alternately constituted by a tube ( T1, T2), the narrow fin (A1, A2) of which is in the lower position (A1) and in the upper position ((A2), so as to allow both the tubes to be vertically offset from the successive sleeves to avoid shrinking excess of the rising air knife, and to support the lower parts of these successive sleeves on the same support (20) extending horizontally from the central volume (18).

The difference in width between the narrow fins A1, A2 and the wide fins B1, B2 is chosen so that the passage section offered to the air between two neighboring tubes T1, T2 is not less than that offered between a tube T1 and the fin B2, of the neighboring sleeve opposite this tube. This difference must however remain small enough for the heat from the tube to easily reach the end of the wide fin.

More preferably, the thickness of the fins is substantially equal to that of the wall of the tube.

Such an exchanger can be manufactured in a particularly simple manner.

When the tube provided with two fins is bent hot to constitute one of the turns of a sleeve, the resulting deformation of the fins constitutes cylindrical surface elements of vertical axis, so that the ends of the fins of two turns consecutive of the same sleeve remain vis-à-vis, ensuring the continuity of the exchange wall with the air.

The positioning of each turn of a sleeve is carried out by resting on a set of equidistant vertical spacers constituting spacers between the sleeves; these spacers are shown in Figure 4; they are arranged parallel to the air streams flowing vertically between the sleeves; these spacers ensure an even distribution of air speed and heat exchange.

• - de maintenir l'égalité des températures dans les spires en vis-à-vis des divers manchons,
• - de constituer une disposition régulière des tubes restant équidistants dans l'ensemble de l'échangeur,
• - de limiter convenablement la vitesse de circulation d'eau et la perte de charge.

The parallel distribution of the water flow between the various sleeves have the effect of:

• - to maintain equal temperatures in the turns vis-à-vis the various sleeves,
• - to constitute a regular arrangement of the tubes remaining equidistant throughout the exchanger,
• - appropriately limit the speed of water circulation and the pressure drop.

In the particular embodiment shown, the number of concentric sleeves is nine. The wall of the tube is 0.8 mm thick, as are the fins. The tube with its two fins has a height of 21.6 mm, and it makes three complete turns in each sleeve. The distance between two fins facing two neighboring sleeves is 7 mm. Vertical spacers E (see Figures 3 and 4) maintain the positions of the sleeves while letting the air circulate vertically.

Claims (4)

1 / Chimney effect water-air convector for heating a room, this convector comprising a succession of parallel vertical heating panels allowing ascending air spaces to circulate between them, these panels extending in a longitudinal horizontal direction, succeeding each other a horizontal transverse direction, consisting of a high extrudable organic polymer provided with a thermally conductive filler, and each comprising - vertical heat exchange surfaces, a vertical succession of longitudinal tubes traversed by hot water, and formed by walls in continuity of material with these exchange surfaces by forming a projection on these surfaces, - This convector further comprising a chimney whose walls are arranged substantially vertically around and above these heat exchange surfaces to channel and accelerate the upward circulation of the heated air in contact with these surfaces, so as to increase the heat exchange between these surfaces and the air circulating in contact with them, this convector being characterized by the fact that said tubes and heat exchange surfaces consist of sleeves (M1, M2, M3) each having a front vertical wall (M1a) and a rear wall (M1r) constituting said panels, and two curved vertical side walls (M11) connecting these front and rear walls, these sleeves surrounding each other by forming a radial succession from a central volume (18) - each of these sleeves being constituted by a tube (T1, T2) carrying fins and wound in a helix and making several turns around the sleeve and going up one stage at each turn, these fins being vertical, all extending two depending on the length of this tube, and being two in number, one in the upper position (B1, B2), the other in the lower position (A1, B2), these two fins occupying at least 80) of the vertical interval between two sections (T1a, T1b) of the same tube (T1) with two adjacent stages, so as to constitute said heat exchange surfaces in the form of a substantially continuous vertical wall. 2 / A convector according to claim 1, characterized in that the two fins of the tube (T1, T2) are, one wide (B1, B2) and the other narrow (A1, A2), the successive sleeves (M1 , M2) being alternately constituted by a tube (T1, T2) whose narrow fin (A1, A2) is, in the lower position (A1) and in the upper position (A2), so as to allow both to shift vertically the tubes of successive sleeves to avoid excessive narrowing of the rising air knife, and to support the lower parts of these successive sleeves on the same support (20) extending horizontally from the central volume (18). 3 / Convector according to claim 1, characterized in that the thickness of the fins (A1, B1) is substantially equal to that of the wall of the tube (T1). 4 / A method of manufacturing a convector according to claim 1, this method being characterized in that the tube (T1, T2) is continuously manufactured with its fins (A1, B1, A2, B2) by a single operation d extrusion, then sectioned into sections (T1, T2), then hot bent to form the sleeves (M1, M2).

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