EP2722615B1 - Tube-type evaporator and method for producing a tube-type evaporator - Google Patents

Description

The invention relates to a tube and shell evaporator comprising a baffle for channeling a flow.

In the field of heat pumps, it is known that an evaporator comprises a shell, a bundle of rectangular section tubes passing through the shell over its entire length and two connections allowing water inlet and outlet inside the shell. grille. In a refrigerant circuit, such an evaporator receives as input a refrigerant and varies its temperature before reintroducing it to a higher temperature in the circuit. Its function is therefore to heat the refrigerant passing through a tubular bundle contained in the shell by taking heat from the outside environment, this heat source being the water introduced and then rejected into the shell through two connections.

As such, the overall performance of the evaporator, and therefore the heat pump, is related to the temperature homogeneity of the fluid contained in each of the tubes of the beam as it passes through the shell. In other words, the fluid passing through the shell must heat up in the same way in each tube of the bundle. Indeed if a beam tube works poorly, that is to say that the temperature variation of the refrigerant it contains does not follow that of the average of the other tubes of the beam, it penalizes the whole of the evaporator by reducing the overall overheating of the apparatus, thus reducing the energy efficiency ratio of the refrigerating system.

It is therefore important to obtain a homogeneous overheating front along the bundle of tubes, so that the superheat is the same at the exit of each tube of the bundle. In particular the upper and lower parts of the shell, between the inner radial surface of the shell and the outer part of the tubular network which is closest thereto, are areas where the heat exchange between the water passing through the shell and the refrigerant flowing through the tubes is different from the heat exchange occurring at the central portion of the tubular bundle.

This is why it is known to use a deflector to prevent water from circulating in the upper and lower parts of the calender thus introducing a preferred heat exchange zone detrimental to the uniform rise in temperature of the fluid. contained in the different tubes.

Two types of deflectors are known whose purpose is to avoid the creation of a preferred heat exchange zone between the tubes located at one of the ends upper or lower beam and the water circulating in the shell. The first type of deflector is the addition of a set of false tubes placed so as to block the flow of water in the upper and lower parts of the calender. The second type of deflector consists of the addition of a sheet placed longitudinally in the vicinity of the upper and lower parts of the tubular bundle.

These two types of deflector reduce the preferred exchange zone between the water of the shell and the lower and upper ends of the tube bundle. However, there is always, for mounting reasons, a game that reduces the effectiveness of false tubes of the first type of deflector. The second type of deflector ensures a good seal, the water being forced to pass in contact with the tubular bundle. However its mounting is delicate and must be done in a perfect way to work properly. In particular, the games are proscribed.

Otherwise, GB-A-1,117,979 discloses a heat exchanger comprising a cylindrical calender and a bundle of tubes. The bundle of tubes is wrapped in a package and the space between the package and the shell is filled with an intermediate agent cast inside the shell. The tubes of the bundle are each housed in a hexagonal section sleeve which forms a honeycomb structure and which extends over most of the length of the exchanger. This structure is bulky and difficult to set up if the heat exchanger is long.

It is these drawbacks that the invention intends to remedy more particularly by proposing a new evaporator in which the circulation of a flow is well controlled, this evaporator being of easy and economical manufacture and making it possible to limit the inhomogeneity of the rise. in temperature of the fluid passing through the tubular bundle.

For this purpose, the invention relates to a tube and shell evaporator. The calender is cylindrical and provided with two inlet and outlet fluid connections. The calender is also traversed along its length, between two end plates, by a bundle of tubes. According to the invention, the evaporator comprises at least one deflector, for a flow flowing in the shell between the inlet and outlet taps, consisting of polymerized resin in place and filling a defined volume between, on the one hand, a portion of the inner radial surface of the shell and, on the other hand, an outer surface of the tube bundle. In addition, the evaporator comprises baffles parallel to the end plates and defining between them a fluid flow path between the inlet and outlet connections, each of the baffles comprising at least one opening connecting two portions of polymerized resin amount located on either side of the baffle.

Thanks to the invention, the introduction of a polymerizable liquid resin deflector allows an effective closure of the volume between the inner radial surfaces high and / or low of the calender and the upper and / or lower portions of the tubular bundle. This closure of the aforementioned volume being performed using a polymerizable liquid resin, it is obtained easily and closer to the lower and / or upper parts of the tube bundle, which ensures a good seal and avoids leaks around the tube bundle. In addition, it is not necessary to use an elongated honeycomb structure to hold the tubes inside the shell. The manufacture of the evaporator is facilitated.

• L'évaporateur comprend au moins un passage obturable reliant l'extérieur de la calandre et un volume interne de la calandre compris entre la quantité de résine polymérisée et le faisceau de tubes.
• La quantité de résine polymérisée occupe les parties haute et basse de la calandre comprises entre la surface intérieure de la calandre et le faisceau de tubes.

According to the advantageous but not obligatory aspects of the invention, an evaporator provided with such a deflector may include one or more of the following features, taken in any technically permissible combination:

• The evaporator comprises at least one closable passage connecting the outside of the shell and an inner volume of the shell between the amount of polymerized resin and the bundle of tubes.
• The amount of polymerized resin occupies the upper and lower portions of the shell between the inner surface of the shell and the bundle of tubes.

1. a) - installer l'évaporateur avec un axe central de la calandre horizontal,
2. b) - remplir un volume délimité, entre, d'une part, une partie de la surface radiale interne de la calandre située en dessous du faisceau de tubes et, d'autre part, une partie externe inférieure du faisceau de tubes, avec une résine polymérisable et liquide,
3. c) - faire polymériser la résine.

The invention also relates to a method of manufacturing an evaporator as previously described and, more specifically, to a method which comprises the steps of:

1. a) - install the evaporator with a central axis of the horizontal grille,
2. b) - fill a defined volume, between, on the one hand, a portion of the inner radial surface of the shell located below the bundle of tubes and, on the other hand, a lower outer portion of the bundle of tubes, with a polymerizable and liquid resin,
3. c) - polymerize the resin.

In addition, the flow of resin in the liquid state on the calender surface takes place through openings passing through baffles parallel to the end plates.

• Le procédé contient une étape supplémentaire d) consistant à retourner de 180° la calandre autour de son axe central et les étapes a) à c) sont à nouveau mises en oeuvre après l'étape d).
• Après la polymérisation de la résine, au moins un passage obturable est créé pour assurer une purge du contenu de la calandre vers le milieu extérieur.
• L'introduction de la résine polymérisable et liquide dans la calandre a lieu avant la mise en place du faisceau de tubes dans la calandre.

According to other advantageous aspects of the invention, such a method comprises one or more of the following characteristics, taken separately or in any technically permissible combination:

• The method contains an additional step d) of returning the calender about 180 ° about its central axis and steps a) to c) are again carried out after step d).
• After polymerization of the resin, at least one closable passage is created to purge the contents of the calender to the outside environment.
• The introduction of the polymerizable and liquid resin into the calender takes place before the introduction of the tube bundle into the shell.

• la figure 1 est une vue en perspective avec arrachement partiel d'un évaporateur conforme à l'invention ;
• la figure 2 est une coupe longitudinale selon le plan II à la figure 1 ;
• la figure 3 est une coupe longitudinale selon le plan III à la figure 1 ;
• la figure 4 est une coupe transversale à plus grande échelle selon le plan IV à la figure 1 vue dans le sens de la flèche F1 ;
• la figure 5 est un agrandissement du détail V à la figure 1 représentant, entre autres, un bouchon de purge mis en place sur la calandre.

The invention will be better understood and other advantages thereof will appear more clearly in the light of the following description of an embodiment of a tubular evaporator according to its principle, given solely by way of example and with reference to the accompanying drawings in which:

• the figure 1 is a perspective view partially broken away of an evaporator according to the invention;
• the figure 2 is a longitudinal section along the plane II to the figure 1 ;
• the figure 3 is a longitudinal section according to plane III at figure 1 ;
• the figure 4 is a cross-section on a larger scale according to plane IV to the figure 1 view in the direction of arrow F1;
• the figure 5 is an enlargement of detail V to the figure 1 representing, among others, a purge plug placed on the calender.

The figure 1 is a perspective view of an evaporator 2 provided with two deflectors 14 _inf , 14 _sup polymerized resin. Each of these deflectors 14 _inf , 14 _sup respectively comprises N sections 14 _inf1 , ..., 14 _infN and 14 _sup1 , ..., 14 _supN . The evaporator 2 comprises a shell 4 comprising two end plates 42, 44 and a central cylindrical shell 46.

The ferrule 46 of the calender 4 is provided with two inlet 8a and 8b outlet of a fluid, such as pure water or mixed with mono-ethylene glycol or mono-propylene glycol. In the example of the figure 1 these connections are located on the same flank of the shell 46. At the figure 1 , the ferrule is shown partly broken away to view the inside of the evaporator 2. Similarly, two sections of the deflectors 14 _inf , 14 _sup , which are located in the fifth compartment of the calender from the left of the figure 1 , are not shown for a better visualization of the interior of the evaporator 2.

The calender 4 also comprises, along its length, baffles 12, parallel to the end plates 42 and 44. They delimit a fluid circulation path between the two connections 8a, 8b, as represented by the flow arrows E to the figure 3 .

X4 is a longitudinal and central axis of the calender 4. This axis is the central axis of the ferrule 46.

The calender 4 is crossed from one end to the other by a beam 100 of rectangular section and composed of tubes 10 placed in the calender 4. This beam 100 also passes through each of the baffles 12 in place inside the grille. The lower and upper surfaces of the beam 10, that is to say the imaginary planar surfaces tangential to the tubes 10 respectively on the top and on the underside of the beam 100, are noted S100 _inf and S100 _sup while the evaporator is in the configuration of FIG. 'use.

For clarity of the drawing, the beam 100 is shown in full only on the left of Figures 1 to 3 , only a tube 10 is shown on the right of these figures and the surfaces S100 _inf and S100 _sup are marked by their traces in the planes of the figures 1 , 2 and 4 . Tie rods 13 connect the baffles 12 to each other and are more particularly visible on the right of the Figures 1 to 3 .

The end plates 42 and 44 respectively define a distribution chamber 442 and a collection chamber 424 made by machining the end plates. The chamber 422 is connected to the outside of the evaporator 2 by two taps 424 and 426. In the same way, the chamber 442 is connected to the outside of the evaporator 2 by two taps 444 and 446. It is thus possible to circulate in the tubes 10 of the beam 100 a refrigerant by introducing it into the chamber 442 by the connections 444 and 446, as represented by the arrow F1, by distributing it to the different tubes within this chamber, then by recovering it in the chamber 422 and discharging it outwards through the connections 424 and 426, as represented by the arrows F2. This refrigerant may be, for example, R-134a type, that is to say tetrafluoroethane, or R-410a type, that is to say a mixture of pentafluoroethane and difluoromethane. S46 denotes the inner radial surface of ferrule 46. S46 _inf denotes the portion of surface S46 located below surface S100 _inf in the configuration of use of evaporator 2. Similarly, S46 _sup of the surface S46 located above the surface S100 _sup in the configuration of use of the evaporator.

As visible at figure 3 the flow path of the fluid between the baffles 12 is partly perpendicular to the fluid flow path in the tubes of the bundle 100. The evaporator 2 thus differs from the heat exchanger of the GB-A-1,117,979 insofar as, in this document, the fluids circulate in parallel manner with respect to each other.

A first deflector 14 _inf polymerized resin is cast in place between the surfaces S42 _inf and S100 _inf . A second deflector 14 _sup polymerized resin is cast in place between the surfaces S46 _sup and S100 _sup .

The baffles 12 are each provided with notches 120 formed in areas of the baffles located below and above the beam 100 in the configuration of use, at their edges. Alternatively, these notches may be replaced by orifices provided at a distance from the edges 121. These notches or orifices are openings allowing the flow of the resin not yet polymerized.

The polymerizable resin may be epoxy-based additive or not.

The polymerizable resin intended to form the deflectors 14 _inf and 14 _sup is placed along the upper and lower parts of the calender 4 and, once polymerized, closes the notches 120 of the baffles 12.

The evaporator 2 also comprises two bleed holes 16a, 16b connecting the internal volume V4 of the shell to the outside environment. One 16a, located in the upper part of the calender, is used for air purges. The other 16b, located in the lower part of the calender, is used for water purges. In condition of use of the evaporator, plugs 18a, 18b close the orifices 16a, 16b.

The water enters the inlet nozzle 8a then into a first compartment C1 defined by the end plate 42 and a first baffle 12.

Upon entering the first compartment, the water comes into contact 10 of the tube bundle tubes 100. Baffle sections 14 and 14 _{inf1 SUP1} accommodated in the first compartment C1 allow to impose upon the water entering the calender 4 a passage closer to the tubes 10 of the bundle 100, ensuring better homogeneity during the transfer of heat energy between the water and the refrigerant contained in each of the tubes 10 of the bundle 100. The polymerized resin poured between the bundle of tubes 100 and the calender 4 forms sections of deflectors 14 _inf1 and 14 _sup1 which guide the passage of fluid closer to the tubes 10 of the beam 100, that is to say, to avoid traffic areas licking not the tubes 10 of the beam 100. The mass of polymerized resin directly participates in guiding the flow E inside the calender 4 being licked by this element. The heat transfer between the fluid flowing in the tubes 10 of the bundle 100 and the fluid flowing in the internal volume of the calender is optimized. In addition, to ensure a homogeneous distribution of the flow of water entering the shell 4, the tubular bundle 100 is rectangular in section as visible on the figure 4 .

Once the water enters the first compartment C1 of the calender, it passes through the N-1 other compartments C2, ..., CN provided with the N-1 other sections of deflector 14 _inf2 , ..., 14 _infn and 14 _sup2 , ..., 14 _supN to exit through the output _quill 8b.

The N-1 baffles 12 delimiting the N compartments C1, ... CN are arranged so as to slow the passage of the water passing through each of these compartments, in order to promote the heat exchange between the water passing through the shell 4 and the refrigerant contained in the tubes 10 of the beam 100.

According to a variant not shown of the invention, the refrigerant and water can flow in the opposite direction to that shown in the figures by the arrows F1, F2, E1 and E2. Thus, the refrigerant can flow from the end plate 42 to the end plate 44 while water can flow from the stitch 8b to the stitching 8a.

The method of placing the resin in the upper and lower parts of the shell is in several stages. The following steps describe a mode of introduction of the deflectors 14 _inf and 14 _sup in the calender 4.

A first step a), consists of installing the evaporator 2 with the central axis X4 of the horizontal grille, the beam 100 already in place in the shell being oriented as when using the evaporator 2 in order to prepare the filling the lower portion of the volume V4.

A second step b) consists in filling a part of the volume delimited between, on the one hand, the lower inner radial surface S46 _inf of the ferrule 46 located below the beam 100 and, on the other hand, the lower surface S100 _inf of the tube bundle 100, with a suitable quantity of polymerizable resin in the liquid state. Under the effect of gravity, the resin is distributed on the bottom of the ferrule 46 to best fill the volume between the bottom of the ferrule and the bundle of tubes 100.

In this step, the liquid resin is injected into the volume V4 through one or other of the connections 8a, 8b.

Once the resin has been injected, it spreads along the inner radial surface of the shell and settles in the bottom of each compartment C1,..., CN thanks to the notches 120 of the baffles 12.

A third step c) is to polymerize the resin. This polymerization is carried out, for example, at room temperature and by adding a curing agent to the resin before it is introduced into the shell. Alternatively, this polymerization can be carried out by heating the resin introduced.

At the end of this step, the amount of resin cured in place forms a lower baffle 14 _inf and closes each of the notches 120 of the baffles 12. This closure contributes to the complete sealing of the evaporator 2.

A fourth step d) consists in turning the shell 4 about 180 ° about its central axis X4 in order to prepare the filling of a second part of the volume V4 previously located in the upper part of the shell and defined between the surfaces S46 _sup and S100 _sup . The fifth and sixth steps are similar to the second and third steps b), c) and consist in filling this second part of the volume V4 with the polymerizable resin in the liquid state through one or other of the connections 8a, 8b and the notches 120 of the baffles 12, then the polymerization of this resin to form the upper baffle 14 _sup comprising the N sections 14 _sup1 , ..., 14 _supN .

A seventh and last step consists, once the polymerized resin is in place, to pierce the purge passages 16a, 16b through the ferrule 46 and the deflectors 14 _inf and 14 _sup and to their closure by plugs 18a, 18b. These openings open just at the level of the polymerized resin, as visible on the figure 5 .

Alternatively, the introduction of deflectors 14 _inf , 14 _sup polymerizable resin can be done before the bundle 100 of tubes 10 is inserted into the calender 4. In this case, after casting in place the deflectors 14 _inf and 14 _sup , one end of the beam 100 is placed on one of the end plates, for example 42, then the beam 100 is inserted along the calender 4, between the deflectors 14 _inf and 14 _sup , so as to the other end of the beam 100 is put in place on the opposite end plate 44. This variant with implementation of the beam 100 after the introduction of the deflectors 14 _inf and 14 _sup is possible only when the evaporator 2 comprises a rectilinear beam 100. In the case of a beam 100 in the shape of a "U", the introduction of the deflectors is only after the introduction of the beam 100 in the shell 4 of the evaporator 2.

Once the deflectors 14 _inf and 14 _sup and the beam 100 set up, the water can flow from the inlet nozzle 8a to the outlet nozzle 8b, through each of the N compartments C1, ... CN being at most close to the tubular bundle 100.

The introduction of the deflectors 14 _inf and 14 _sup imposes a circulation of water in the calender 4 to the nearest tubes 10 of the beam 100, thus promoting a homogeneous rise in temperature of the refrigerant in each of the tubes 10.

The polymerized resin maintains the baffles 12 which can not move. The assembly composed by the baffles 12 and the shell 4, also called skeleton, is stiffened by the resin forming the deflectors 14 _inf and 14 _sup . Thus, the resin participates in the reduction of parasitic vibrations which appear under the effect of the circulation of water.

This technical solution makes it possible to perform the function of the baffle so as to control the flow of water into the shell without welded seam or sheet. In addition it adapts to all types of calenders since the process of introducing the resin is based on the leveling of a liquid surface under the effect of gravity. We can generalize this process to any type of calender 4, the method being the same for all sizes.

In addition, the use of the resin is compatible with the brine and the resin does not degrade.

In another variant, the introduction of the resin is by two connections not shown in the figures and similar to the bleed holes 16a, 16b. These connections are located 90 ° from the bleed holes 16a, 16b and connect the inside and outside of the shell 4 at the deflectors 14 _inf and 14 _sup .

The technical characteristics of the embodiments and variants envisaged above can be combined with each other.

Claims (7)

1. Evaporator (2) comprising tubes (10) and a shell (4), the shell being cylindrical and having two connector fittings providing an inlet (8a) and outlet (8b) for fluid in the shell, the shell also being traversed by a bundle (100) of tubes (10) across its length between two end plates (42, 44), such that

   - at least one deflector (14_inf, 14_sup) for a flow circulating through the shell (4) between the connector fittings (8a, 8b) is formed by a quantity of resin polymerised in situ and filling a volume bounded between, on the one hand, a part (346_inf, S46_sup) of the internal radial surface of the shell and, on the other hand, an external surface (S100_inf, S100_sup) of the bundle of tubes (100), characterised in that

   - the evaporator comprises baffle plates (12) parallel with the end plates (42, 44) and defining between them a fluid circulation path between the inlet (8a) and outlet (8b) connector fittings, each of the baffle plates comprising at least one opening (120) connecting two portions (14_inf1, 14_inf2, ... 14_infN, 14_sup1, 14_sup2, ... 14_supN) of the quantity of polymerised resin disposed on either side of the baffle plate (12).
2. Evaporator as claimed in claim 1, characterised in that it comprises at least one blankable passage (16a, 16b) connecting the exterior of the shell (4) and an internal volume of the shell disposed between the quantity of polymerised resin (14_inf, 14_sup) and the bundle of tubes (100).
3. Evaporator as claimed in one of the preceding claims, characterised in that the quantity of polymerised resin (14_inf, 14_sup) occupies the entire volume of top and bottom parts of the shell disposed between the interior surface (S46_inf, S62_sup) of the shell and the bundle of tubes (100).
4. Method of producing an evaporator (2) comprising tubes (10) and a shell (4), the shell being cylindrical and having two connector fittings providing an inlet (8a) and outlet (8b) for fluid in the shell, the shell (4) also being traversed by a bundle (100) of tubes (10) across its length between two end plates (42, 44), such that it comprises of:

   a) - placing the evaporator with a central axis (X4) of the shell horizontal,

   b) - filling a volume bounded between, on the one hand, a part (S46_inf) of the internal radial surface (S46) of the shell disposed underneath the bundle of tubes (100) and, on the other hand, a lower external surface (S100_inf) of the bundle of tubes with a quantity of liquid and polymerisable resin,

   c) - polymerising the resin, characterised in that
   the resin in the liquid state flows on the surface of the shell through openings (120) traversing baffle plates (12) parallel with the end plates (42, 44).
5. Method as claimed in claim 4, characterised in that it comprises an additional step comprising:

   d) - turning the shell 180° about its central axis, and in that steps a) to c) are repeated after step d).
6. Method as claimed in one of claims 4 and 5, characterised in that after the resin has polymerised, at least one blankable passage (16a, 16b) is created to enable the contents of the shell (4) to be purged to the external environment.
7. Method as claimed in one of claims 4 to 6, characterised in that liquid and polymerisable resin in introduced into the shell (4) before fitting the bundle of tubes (100) in the shell.

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