Hollow plate heat exchangers

Abstract

One of these heat exchangers ( 76 ) consists of a stack of thin-metal walled hollow platelets ( 7 S 1 -J 5 ), 12 cm long and 5 wide. Each of these walls has a central region stiffened by alternating bosses with steep slopes, situated between two connection regions. Each wall is made by pressing then cutting an appropriate sheet of metal (aluminium 0.3 mm thick). The edges of the two fin walls form steps, symmetrically welded, the height of each step determining the internal half-thickness of a fin. Each platelet connection region ends in a narrow mouth with a cross section that has the same surface area as the embossed central region, and is welded to the edges of a slot made in an external manifold ( 80 - 82 ). The thickness of the internal channel of a platelet is about 0.4 mm when the fluid concerned is a liquid (water) and that of the spaces between the platelets is 7 mm when the other fluid is a gas (air). By hot pressing or thermoforming, sheets of glass or polymer may also be used but the performance is not as good. A radiator can be made of several exchangers mounted in parallel on each side of two flat main manifolds. Applications: any heat exchangers with high volumetric conduction, low weight and low pumping and ventilating power.

1 - 1 . (canceled) 
   
   
       12 . A Heat exchanger with low weight and high bulk conductance, capable of handling fluids at high differential pressure and temperatures, in which:
 hollow metal plates with a narrow internal channel, are stacked evenly spaced and connected to external manifolds;   these plates comprise an embossed central zone, located between two connecting zones provided with narrow openings with a surface area approximately equal to the area of a cross-section of the central zone;   the walls of these plates have been produced by stamping and cutting a metal sheet;   the lateral edges of the two walls of a hollow plate are welded;   
     wherein:
 the walls of each hollow plate are both rigid and very thin, their embossed central zone having one or more sets of aligned alternating bosses, provided with steep strain hardened faces, creating a large number of sharp edges, orientated obliquely and/or perpendicularly to the alignment of the bosses; 
 the gap between opposite faces is uniform, very small, exactly known and practically constant, in the range of the envisaged differential pressures; 
 the gaps separating the plates are relatively narrow. 
 
   
   
       13 . The Heat exchanger, derived from the exchanger according to  claim 12 , wherein:
 it is made up of glass or polymer hollow plates, with a thin internal channel, stacked with constant spacing and connected to external manifolds;   the walls of these hollow plates have been produced by hot stamping or thermoforming and then cutting from a sheet of glass or polymer;   these plates comprise an embossed central zone, located between two connecting zones provided with narrow openings with an area approximately equal to the area of a transverse cross-section of the central zone;   the lateral edges of the two walls of a hollow plate are welded;   the central zone of the plates has one or more sets of aligned alternating bosses, provided with steep faces, creating a large number of sharp edges, orientated obliquely or perpendicularly to the alignment of the bosses;   the gap between opposite faces is uniform, small, exactly known and practically constant, in the range of the envisaged differential pressures;   the gaps separating the plates are relatively narrow.   
   
   
       14 . The Heat exchanger according to  claim 12 , wherein:
 each hollow plate comprises at least two rows of alternating bosses;   two adjacent rows are separated by a narrow, straight partition, formed by two internal stamped or thermoformed protrusions, assembled by welding;   the height of these protrusions is equal to half of the maximum value of the internal thickness of these hollow plates.   
   
   
       15 . The Heat exchanger according to  claim 13 , wherein:
 each hollow plate comprises at least two rows of alternating bosses;   two adjacent rows are separated by a narrow, straight partition, formed by two internal stamped or thermoformed protrusions, assembled by welding;   the height of these protrusions is equal to half of the maximum value of the internal thickness of these hollow plates.   
   
   
       16 . The Heat exchanger according to  claim 12 , wherein:
 the angles formed by the normals to two adjacent faces of the alternating bosses measure at least 30°, so that the sharp edges of these faces can be effective in the creation of turbulence and in withstanding the pressure differences between the fluids;   the maximum angle of the normals to two adjacent faces is limited by the restrictions imposed on the conditions under which the material in question is stamped or thermoformed.   
   
   
       17 . The Heat exchanger according to  claim 13 , wherein:
 the angles formed by the normals to two adjacent faces of the alternating bosses measure at least 30°, so that the sharp edges of these faces can be effective in the creation of turbulence and in withstanding the pressure differences between the fluids;   the maximum angle of the normals to two adjacent faces is limited by the restrictions imposed on the conditions under which the material in question is stamped or thermoformed.   
   
   
       18 . The Heat exchanger according to  claim 12 , wherein:
 the alternating bosses have, of their own, two lateral faces in the form of an isosceles trapezium, having a common longitudinal edge and, shared, two central rhomboid faces;   the long diagonal of the rhomboid faces can measure several tens of times the thickness of the wall of the plates.   
   
   
       19 . Heat exchanger according to  claim 13 , wherein:
 the alternating bosses have, of their own, two lateral faces in the form of an isosceles trapezium, having a common longitudinal edge and, shared, two central rhomboid faces;   the long diagonal of the rhomboid faces can measure several tens of times the thickness of the wall of the plates.   
   
   
       20 . The Heat exchanger according to  claim 12 , wherein:
 the alternating bosses have, of their own, two lateral faces in the form of an isosceles triangle for the bosses and for the hollows and, shared, two central hexagonal faces for the bosses and for the hollows, these hexagonal faces having a common transverse edge;   the gap between the transverse edges of the hexagonal faces can measure several tens of times the thickness of the wall of the plates.   
   
   
       21 . Heat exchanger according to  claim 13 , wherein:
 the alternating bosses have, of their own, two lateral faces in the form of an isosceles triangle for the bosses and for the hollows and, shared, two central hexagonal faces for the bosses and for the hollows, these hexagonal faces having a common transverse edge;   the gap between the transverse edges of the hexagonal faces can measure several tens of times the thickness of the wall of the plates.   
   
   
       22 . Heat exchanger according to  claim 12 , wherein the embossed central zone of each hollow plate is connected to the external manifolds by two connecting zones provided with lateral edges having a significant slant and smooth walls comprising portions of truncated cones. 
   
   
       23 . Heat exchanger according to  claim 13 , wherein the embossed central zone of each hollow plate is connected to the external manifolds by two connecting zones provided with lateral edges having a significant slant and smooth walls comprising portions of truncated cones. 
   
   
       24 . Heat exchanger according to  claim 12 , wherein the opposite faces of a hollow plate have parallel walls and the gap separating these walls is constant and of the same order of magnitude as their thickness. 
   
   
       25 . Heat exchanger according to  claim 13 , wherein the opposite faces of a hollow plate have parallel walls and the gap separating these walls is constant and of the same order of magnitude as their thickness. 
   
   
       26 . Heat exchanger according to  claim 12 , wherein symmetrical boss faces appear to be cut in a diamond pattern and comprise several secondary faces and are provided with complementary sharp edges. 
   
   
       27 . Heat exchanger according to  claim 13 , wherein symmetrical boss faces appear to be cut in a diamond pattern and comprise several secondary faces and are provided with complementary sharp edges. 
   
   
       28 . The Heat exchanger according to  claim 12 , wherein:
 the external manifolds of the hollow plates have an aerodynamic profile capable of minimising the drag of the exchanger;   each manifold is made up of two elongated shells, one for connection to the plates and the other for front closure, their transverse cross-section is U-shaped and they are fixed to each other by a weld line.   
   
   
       29 . The Heat exchanger according to  claim 13 , wherein:
 the external manifolds of the hollow plates have an aerodynamic profile capable of minimising the drag of the exchanger;   each manifold is made up of two elongated shells, one for connection to the plates and the other for front closure, their transverse cross-section is U-shaped and they are fixed to each other by a weld line.   
   
   
       30 . A Compact, light radiator with high or very high thermal conductivity, wherein:
 it comprises two identical groups of heat exchangers with hollow plates made from metal, glass or polymer, according to  claim 18 ,   these two groups are associated with two thin main upstream and downstream manifolds, provided with flat rectangular trapezoid surfaces, slightly separate from each other and arranged so that their square corners are opposite each other;   the individual upstream and downstream manifolds of the exchangers in each group are connected respectively, at constant intervals slightly larger than the width of the central zone of the exchangers, to two homologous surfaces of the two main upstream and downstream manifolds.