FR2813663A1 - Heat exchanger plate for radiator has a cellular channel panel with a manifold at one end for connecting the channels - Google Patents

Abstract

The heat exchange for a radiator or heat exchanger has extruded plastics panels forming internal cells of square section. The exchanger has U-section gutters (4) defining and internal collection space. the lips of the gutter are glued directly to the sides of the panel (1). Each gutter has spacing washers and openings for fluid pipe connections.

Description

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Heat exchanger using extruded honeycomb plates. Plate heat exchangers generally comprise a stack of plates spaced by wedges, constituted either by corrugations of alternating orientations or by intermediate corrugated and pierced plates, defining two paths of fluids, in the even and odd sheets. The stack is maintained by tie rods. The edges of the plates are arranged to provide lateral sealing of the fluid paths. We consider here especially the so-called methodical exchangers, with counter-currents, in which the two fluid paths go in opposite directions. At the ends, the two routes are collected and connected to external circuits, by various arrangements which give rise to the main difficulties of construction, since the supports between plates cannot be extended in a simple manner in the collection areas. In such plate exchangers, the two paths, even of clearly different fluids, are generally designed in the same way, with spacings between identical plates. According to the present invention, on the contrary, a first circuit is constituted by hollow plates closed laterally , each comprising two skin walls and internal tie rods, and containing one of the fluids in circulation. The other fluid passes into the spaces maintained between the hollow plates. These hollow plates can be formed by extruded cellular plates in plastic material and in particular in polycarbonate, available on the market. We mainly consider the ladder section plates, with two walls linked by thin webs, forming parallel channels of approximately square section in which a fluid can circulate.

According to the invention, primary collectors are adjusted to each end of the hollow plate, open on the channels of the first fluid. Secondary collectors connect the primary collectors and are connected to external circuits. The primary collectors can be thin enough to allow the passage of the second fluid between them in a straight line, but can also, thicker, close the passage, the second fluid then being deflected laterally in the vicinity of each end. Maintaining primary collectors between them contributes to ensuring a suitable thickness between the plates for this route, subject to interposing between the hollow plates, from place to place, shims which may consist of corrugated plastic ribbons .

According to the invention, a primary collector at the end of an extruded honeycomb plate consists of a thin-walled gutter with a U-section with two substantially parallel walls,

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 fitted to the end of the plate which is cut along a contour in the concave assembly, forming an internal space onto which the channels of the plate open. The two walls of the gutter are pierced with opposite communication orifices allowing secondary collection in a stack of plates.

According to an extension of the invention, it is possible to use a plate of single thickness, for example as a radiator or as a solar panel, provided with the same type of primary collector but in which the gutters can take on greater thickness.

The invention will be described using the following figures Fig 1. Perspective view of an end of the plate and of the primary collection gutter, Fig 2. Perspective view of a thick corrugated washer, Fig 3. Sectional view of several ends of plates with the collecting members, Fig 4. Cross-section view of one end of solar panel for water heating.

The plate 1 comprises a collection of square channels 2, 2 '..., for example with a total thickness of 4 mm and a wall thickness, for the two sides of the plate and for the connecting webs, of the order 0.15mm. Collection widths of the order of 400 mm are envisaged, for stacks of approximately 60 plates spaced for example by 3 mm, ie a total thickness of 60 x 7 = 420 mm and an air passage section of 0.072 m2. . This module, for a height of 2m, corresponds to an exchange surface of 96 ml. The fluid passing between plates, in particular air at atmospheric pressure, can be driven at a speed of the order of 3 m / s corresponding to a flow of 0.216 m3 / s. The fluid passing through the plates is for example water, at a total flow rate of 0.5 kg / s. It is reasonable to choose a diameter of the order of 35mm for the secondary collector, opening on one side. the water speed reaching 0.52 m / s and the pressure drop at each manifold about 135 Pa. The gap between plates for the air circuit could be smaller, to obtain, particularly in desalination, a very small temperature difference between the two fluids at each level. For use, for example, in air conditioning, it is possible to choose deviations between upper plates and the dimensions of the manifold dimensions are less acute. The pressure drop in the water channels is negligible and one could choose thinner plates, but the thickness of 4 mm corresponds to an industrial availability, and to the desire to make collectors exceeding very little the thickness plates.

Figure 1 shows a cutout of the end of the honeycomb plate, which forms a collection space 3 using a straight gutter 4 with a straight fold, the sealing connection to the two corners 5 and 5 'being ensured by a simple putty . The cut is therefore generally concave. The gutter, glued on both sides of the plate, can be made of sheet steel

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 thin stainless steel or from an extruded plastic profile. If the cut was straight, a box should be used.

The gutter carries at least two circular openings 6 and 6 'facing each other, to allow secondary collection in a stack of plates, the cutout of the alveolar plate adjusting with a free space around these orifices, Figure 2 shows a washer corrugated 7, for example plastic, to allow the passage of the fluid while maintaining the thickness.

Figure 3 shows in section a set of plate ends, the orifices 6, 6 'of the various plates aligning on a secondary collection axis, with the interposition of the washers 7 inside the gutters and of washers such as 8 between the plates, provided with shoulders to allow alignment between plates under clamping. This tightening can be ensured by threaded tie rods along the collection axis and centered from place to place by special washers not shown. Rivets such as 9 can provide additional maintenance of gutters under pressure.

A methodical exchanger is constituted by stacking honeycomb plates thus equipped at both ends and provided with spacers between the plates and sealing strips along the lateral edges, and by adjusting external conduits on the one hand on the axes. secondary collection described on the other hand on the outlets of the stack between the primary collectors. The extruded plate heat exchangers thus formed can be of economical construction. The material envisaged is polycarbonate, relatively rigid, usable up to 100 C, resistant to corrosion and aging, not very sensitive to thermal fatigue. It is possible to form exchangers, of high efficiency thanks to the thinness of the wall of the channels obtained industrially, of the order of 0.15 mm, and usable in particular in air conditioning and air treatment, and for certain water desalination processes sea by humid air cycle.

Panels thus collected, but not stacked, can constitute wall radiators or solar panels. The extruded plate can then be of the type comprising internal walls 10 parallel to the external walls, forming two or three layers of channels, the collection being carried out on a single layer and the other layers remaining filled with inert air which provides thermal insulation. . For a home radiator, it is thus possible to provide insulation on the wall side. For a solar panel (Fig 4), durable through the integration, acquired industrially, of a surface protection against UV radiation, the upper layer 11 is closed at the ends and left at atmospheric pressure thanks to transverse openings 12 and a vent 13. Passed through by solar radiation, it limits cooling by the atmosphere, while the lower heating layer 14, coated from below with a black coating, is collected and supplied with water by day. For desalination, such solar panels should be spread over a hot salt water storage tank. They are then completed by a glued floating and insulating layer 15, for example made of polystyrene, which limits the night cooling of the tank.

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Claims (7)

CLAIMS. 1. Plate for heat exchanger, characterized in that it is constituted by a plate 1 called alveolar (forming a set of parallel channels, between two thin wall plates and a set of perpendicular cores) and in that it has at least one end a primary collector for all the channels. 2. Plate according to claim 1, characterized in that the collector is a gutter 4 of sheet metal bent in a U and forming two substantially parallel walls, covering the end of the plate whose edge is cut along a path in the concave assembly , thus providing a primary collection space 3 between two gutter walls. 3. Plate according to the preceding claims, characterized in that the two walls of each primary collector are pierced with orifices 6, 6 'in the transverse direction, an openwork washer being interposed between the two walls around this orifice. 4. Plate assembly according to claim 4, characterized in that the orifices of the collectors are aligned and in mutual support with the interposition of thickness and centering washers, forming a secondary collection axis and ensuring the desired spacing between the plates at the level of the collectors. 5. Heat exchanger consisting of a set of cellular plates provided at the two ends of collectors according to claim 4. 6. Exchanger plate according to claims 1 or 2, the cellular plate being of the extruded type and comprising one or more internal walls 10, 10 ′ parallel to the external walls, only one of the channel layers thus formed being provided with primary collectors. 7. Radiator or solar panel for heating water, consisting of at least one cellular plate according to claim 6.