FR2681420A1 - WATER BOX AND EXPANSION VESSEL DEVICE FOR HEAT EXCHANGER WITH VERTICAL TUBES BEAM, AND HEAT EXCHANGER HAVING SUCH A DEVICE. - Google Patents

Abstract

The invention relates to a water box and expansion vessel device for a vertical tube bundle heat exchanger. The device (10) comprises a water box (20) with a generally horizontal arrangement suitable for being mounted at the upper end of a bundle (12) of vertical tubes (16) and an expansion vessel (42) available general horizontal placed above the water box and communicating with it by a multiplicity of passages (66, 72, 76) distributed over at least part of the length of the water box and the expansion tank to ensure a fluid communication between them and facilitate the expansion of the liquid and its degassing. The invention is particularly applicable to heat exchangers for cooling motor vehicle engines.

Description

Water box and expansion tank device for heat exchanger

  The invention relates to a device for a water box and an expansion vessel for a tube bundle heat exchanger.

  and a heat exchanger comprising such a device

tif.

  Devices of this type are already known which comprise a water box of general horizontal disposition adapted to be mounted at the upper end of the bundle, as well as an expansion tank with a general horizontal disposition arranged above

  from the water box and communicating with her.

  The lower end of the bundle is then adapted to receive another water box, or lower water box, to ensure the circulation of a liquid that enters the heat exchanger through an inlet pipe and leaves the heat exchanger in most cases, the inlet manifold depends on the water box and expansion vessel, while the outlet manifold depends on the box

at lower water.

  Devices of this type, which constitute a water box with integrated expansion vessel, are used in particular in heat exchangers for cooling a motor vehicle engine with a liquid, generally brine, which circulates in a closed circuit and is cooled by heat exchange with air passing through the

bundle of tubes.

  It is already known from documents FR-A-2 395 397 and US-A-

  3,939,901, devices of this kind in which there is provided a single passage communicating the water box and the expansion tank to allow on the one hand the expansion of the liquid and on the other hand the degassing of the liquid, the gases being thus

  collected in the expansion vessel.

  In the aforementioned devices, the single passage providing communication between the water box and the expansion vessel consists of a tube which depends on a separating wall and which

  protrudes upward into the expansion vessel.

  This known solution is not satisfactory because it does not allow an optimal expansion of the liquid within the device In addition, it does not allow a good outgassing of the liquid because the bubbles, possibly present in the water box, must collect in a unique place to be able to be next

  evacuated to the expansion vessel.

  In addition, the aforementioned known devices are formed from a large housing in which a partition is provided leaving the single communication passage, to thereby delimit a lower compartment constituting the actual water box and a top compartment constituting the expansion vessel Because this known solution uses a large housing, it has the disadvantage

  major to not allow a satisfactory resistance to pressure.

  The object of the invention is in particular to overcome the aforementioned drawbacks. The invention proposes for this purpose a water box device and

  expansion vessel of the type defined in the introduction, this

  tif comprising a multiplicity of passages distributed over at least

  part of the length of the water box and the expansion vessel

  to provide fluid communication with each other.

  As a result, the water box and the expansion vessel communicate with each other by a multiplicity of passages, which facilitates

  fluid exchange within the device itself.

  In this way, a good compensation of the variations of liquid within the device and at the same time an excellent degassing is obtained since the gas bubbles possibly present in the water box can be evacuated towards the expansion vessel by means of several passages spread over at least one

  part of the length of the water box.

  Advantageously, the water box is delimited by an open-face wall adapted to be connected to the tube bundle, while the expansion tank is delimited by a tubular wall, the water box and the expansion tank being monobloc and connected by a web of material and by tubular walls forming cylindrical passages communicating between the water box and

the expansion tank.

  Thus, the device can be made in one piece by

  molding of a suitable plastic material.

  In a first embodiment of the invention, the device comprises a liquid inlet pipe which opens directly into the water box, the communication passages comprising a large bore located near the liquid inlet pipe. and several passages of smaller

caliber.

  The large gauge passage is mainly intended to ensure a communication of liquid between the water box and the expansion vessel, while the passages of smaller size are mainly intended for degassing for the evacuation of the bubbles.

  any gas present in the water box.

  Advantageously, the device then comprises a def reader disposed in the water box vis-à-vis the liquid inlet tubing, so that the passage of large caliber opens into the water box in a region between the manifold

entry and the def reader.

  This deflector contributes to good communication between the water box and the expansion tank and allows in particular to reduce the

duration of degassing.

  In this first embodiment of the invention, the water box is provided with an insulated compartment which, on the one hand, communicates with the expansion vessel by one of the small passages and which, d On the other hand, is suitable for communicating with a lower water box via at least

a beam tube.

  This results in at least one tube isolated from the other tubes of the bundle and which makes it possible to ensure direct communication of the

  expansion tank with the lower water box.

  In a second embodiment of the invention, the device comprises a liquid inlet tubing which opens

  directly in the expansion vessel, the communication passages

  being of the same size, the total cross-section

  is at least equal to the section of the inlet manifold.

  This solution makes it possible to reduce as much as possible the loss of

load on the liquid.

  In this second embodiment of the invention, the device advantageously comprises a deflector disposed in the expansion vessel near the inlet manifold and oriented towards the

  the top, which facilitates the degassing of the liquid.

  Advantageously, the liquid inlet manifold is integral

  a lid attached to the expansion tank.

  Thus, in the case where this expansion vessel is delimited by a tubular wall, this cover is attached to one of the ends

  of this tubular wall, the other end is closed.

  In a third embodiment of the invention, the device comprises a liquid inlet pipe which opens directly into the expansion tank, the water box comprising a partition dividing it into two compartments, one of which communicates with the expansion vessel through the aforementioned communication passages and the other communicates

with an outlet pipe.

  In another aspect, the invention relates to a heat exchanger comprising a bundle of vertical tubes, a water box device and expansion vessel as defined above mounted at the upper end of the bundle of tubes, and a box

  lower water mounted at the lower end of the beam.

  In the description that follows, made only as an example,

  Referring to the accompanying drawings, in which: Figure 1 is a longitudinal sectional view of a water box device and expansion vessel according to the first embodiment above and mounted at the upper end of a tube bundle, the sectional view being taken along the line II of Figure 2; Figure 2 is a sectional view taken along the line II-II of Figure 1; Figure 3 is a sectional view of a heat exchanger comprising a water box and expansion vessel device according to Figures 1 and 2; Figure 4 is a longitudinal sectional view of a water box and expansion vessel device according to the second embodiment of the invention; Figure 5 is a longitudinal sectional view of a heat exchanger comprising a water box and expansion tank device according to Figure 4; and FIG. 6 is a sectional view of a heat exchanger comprising a water box and expansion vessel device.

  according to the third embodiment of the invention.

  Referring firstly to Figures 1 to 3 which show a water box and expansion vessel device 10 to be mounted horizontally at the upper end of a vertical beam 12 whose lower end is connected to a lower water box 14 (Figure 3). The bundle 12 comprises a multiplicity of parallel tubes 16 arranged in two sheets (FIG. 2) and extending in a generally vertical direction. The tubes 61 pass through a multiplicity of fins 18 which extend parallel to each other and perpendicular to the direction of the beam tubes. The device 10 comprises a generally horizontal water box 20 having a wall 22 having a rectangular open face delimited by a peripheral rim 24 for mounting, in a manner known per se, the box

  20 on a manifold 26, also called "plate holes".

  This collector comprises a multiplicity of holes 28 intended to be traversed respectively by the upper ends of the

tubes 16 of the beam.

  The wall 22 affects, in cross section, the general shape of a

  Inverted U with increasing height from an end wall

  The wall 22 thus delimits, in combination with the walls 30 and 32, a chamber 36 which, on the one hand, communicates with the tubing 34 and, on the other hand, with the tubes 16 of the bundle A inside the water box 20 is provided an insulated compartment 38 which is limited by a wall 40 attached to the wall 22 and extending to The compartment 38 communicates with at least one tube of the bundle, in the example with two tubes referenced 16 'to distinguish them

of the remaining tubes 16.

  The device 10 further comprises an overall horizontal expansion vessel 42 situated above the water box 20. The expansion vessel 42 is limited by a tubular wall 44 whose height varies from a bottom wall 46 arranged close to the bottom wall 32 of the water box 20 to an open face 48 disposed near the bottom wall 30 of the water box 20 The open face 48 is intended to receive a cover 50 carrying a level detector 52 extending to

  inside the expansion tank in a quiet room

  54 defined by a wall 56 depending on the cover 50 and

provided with an opening 58.

  The tubular wall 44 comprises a filling base 60 closed by a setting plug 62. The wall 44 thus delimits, in combination with the bottom wall 46 and the cover 50, an internal chamber 64 intended to ensure expansion and degassing.

  of the liquid contained in the water box.

  The water box 20 and the expansion tank 42 are made in one piece by molding a suitable plastic material. The wall 22 of the water box 20 and the wall 44 of the expansion tank 42 are interconnected by a web of water. material 66 which is interrupted from place to place to provide a number of communication passages between the chamber 64, on the one hand, and the

rooms 36 and 38, on the other hand.

  Thus, the device comprises a communication passage 66 of large caliber disposed near the outlet of the pipe 34, the passage 66 being delimited by a cylindrical wall 68 which connects the water box and the expansion tank inside the Chamber 36 of the water box 20 is provided a defender 70 (Figure 1) which is located vis-à-vis the inlet manifold 34, so that the passage 66 opens between the tubing

34 and the deflector 70.

  The device 10 further comprises four communication passages.

  72 spaced along the length of the water box and the expansion vessel and having a caliber smaller than that of the passage 66 Each of the passages 72 is delimited by a wall

  cylindrical tubular 74 which connects the walls 22 and 44.

  Furthermore, the device comprises a communication passage 76 of a size close to that of the passages 72 and delimited by a cylindrical wall 78 which also connects the walls 22 and 44 and which

  communicates with the compartment 38 defined above.

  Bottom water box 14 (Figure 3) communicates with all

  beam tubes and it has an outlet pipe 80.

  The heat exchanger shown in FIG. 3 operates in the following manner. The heat exchanger receives a liquid to be cooled, for example brine from the cooling circuit of a motor vehicle engine.

  enters the chamber 36 of the water box 20 through

  This liquid then gains the bottom water box 14 through the tubes 16, as indicated by the arrows F. The liquid then leaves the box.

  lower water 14 through the outlet pipe 80.

  The variations in volume of the liquid are absorbed by the chamber 64 of the expansion tank 42. The excess liquid enters the chamber 64 mainly through the passage 66 of large caliber while the passages 72 serve essentially to degassing the liquid. Any gas contained in the chamber 36 can collect at various locations along the wall 22 to be discharged into the chamber 64 of the expansion vessel through the passages 72. It should be noted that the presence of the deflector 70 also contributes to better degassing since the bubbles possibly present in the liquid entering the device 10 through the pipe 34 are captured by the deflector 70 and oriented towards the passage 66 The liquid flowing in the chamber 64 of the expansion tank reaches the water box lower 14 via the passage 76, the chamber

isolated 38 and the tubes 16 '.

  Reference is now made to FIGS. 4 and 5 in which the elements homologous to those of the embodiment of FIGS. 1 to 3 are designated by the same reference numerals.

increased by 100.

  The device 110 of FIGS. 4 and 5 comprises a water box 120 of general horizontal disposition delimited by a wall 122 of curved shape and by two bottom walls 130 and 132 forming together a rim 134 of rectangular contour for the assembly of a The wall 132, which is higher than the wall 130, receives a level detector 152 which extends into a plenum 154 delimited by a wall 156 which is attached to the wall 122 and extends in the direction the collector, but without touching it The wall 122 and the

  walls 130 and 132 define together a chamber 136 communicating

  as with all the tubes 16 of the beam 12.

  The device 110 further comprises an expansion vessel 142 which extends horizontally above the water box 130 and which is delimited by a tubular wall 144, a bottom wall 146 disposed near the wall 132 and by a lid 150 attached to an open face 148 of the wall 144 of the lid depends, on one side, a tubing 134 of liquid inlet and, on the opposite side, a baffle 170 which extends inside the chamber 164 and which is directed upwards, the wall 144 receives a filling base 160 closed by a setting plug 162 The walls 122 and 144 are connected by a web of material 166 and the respective tubular walls 174 of four passages The communication passages 172 between the expansion tank and the water box are distributed over the entire length of the box and their total section is at least equal to the section of the pipe 134 so that the pressure drop is mini As shown in the figure, the device 110 is mounted at the upper end of a beam 112, formed of tubes 116 and fins 118, whose lower end communicates with a water box 114 provided with

an outlet pipe 180.

  The exchanger of FIG. 5 operates in the following manner. The liquid enters the chamber 164 of the expansion vessel through

  through the inlet manifold 134 The possible gases

  The liquid in the liquid tends to be deflected upwards by the deflector 170. The liquid then gains the chamber 136 of the water box 120 via the four passages.

  172 and from there gains the lower water box 114 through

  of the set of tubes 116 of the beam, to be then

  discharged through the outlet pipe 180.

  In the embodiment of FIG. 6, to which reference is now made, the elements similar to those of FIG. 1 are designated with the same numerical references increased

of 200.

  The device 210 comprises a horizontal general-purpose water box 220 delimited by a wall 222 and by two end walls 230 and 232. These three walls together define an assembly flange 234 for a collector 226.

  receiving a beam 212 formed of tubes 216 and fins 218.

  The lower end of the beam communicates with a lower water box 214, which has no outlet pipe. From the wall 222 depends a partition 240 which bears against the collector 226, so as to provide two separate chambers 236 and 236 'communicating respectively with two

halves of beam 212.

  The device 210 further comprises an expansion vessel 242 disposed horizontally and above the water box 220. The expansion vessel 242 is delimited by a tubular wall 244 attached to the wall 222 by a web of material 266, and only by an end wall 246 and a cover 250 mounted on an open face 248 of the wall 244.

  base 260 closed by a taring plug 262.

  In the embodiment of FIG. 6, the inlet of the liquid is effected by an inlet pipe 234 connected laterally.

  on the wall 244 near the bottom wall 246.

  In addition, the water box 220 has an outlet pipe

  280 which communicates with the compartment 236 '.

  The expansion vessel defines a chamber 264 which communicates with the chamber 236 of the water box via three calibrated passages 272 distributed over a portion of the length of the water box and the expansion tank. passages are each limited by a tubular wall 274 which connects the walls 222 and 244 As in the case of the previous embodiment, the total section of the three passages 272 must be at least equal to the section of the tubing 234 so that the loss Thus, in the case of the heat exchanger of FIG. 6, the liquid enters the chamber 264 of the expansion tank 242 via the inlet pipe 234 and gains

  then the compartment 236 of the water box 220 through

  The liquid then gains the bottom water box 214 through one half of the tubes 216 of the bundle 212 and thence to the chamber 236 'through the other half of the bundle tubes. The liquid then leaves the water box. In the heat exchanger of FIG. 6, the flow of the fluid is thus obtained in two passes in opposite directions (U-shaped circulation) and not a single-pass circulation (I-circulation). in the case of the preceding figures. In the various embodiments of the invention, the water box device can be formed in one piece by molding a plastic material, the expansion vessel being

  then closed by an attached cover 50, 150 or 250.

  The water box and expansion vessel device of the invention

  tion finds particular application in heat exchangers for cooling combustion engines

internal for a motor vehicle.

Claims (10)

claims   1. Water box and expansion vessel apparatus for vertical tube heat exchangers (12; 112; 212)   (16; 116; 216), comprising a water box (20; 120; 220) provided with   horizontal arrangement adapted to be mounted at the upper end of the bundle (12; 112; 212) and an expansion tank (42; 142; 242) of generally horizontal arrangement placed above the water box and communicating with the it, characterized in that it comprises a multiplicity of passages (66,72,76; 172; 272) distributed over at least a part of the length of the water box and the expansion vessel to ensure fluid communication between them.   2. Device according to claim 1, characterized in that   the water box (20; 120; 220) is delimited by a wall (22; 122;   222) having an open face adapted to be connected to the tube bundle, in that the expansion vessel (42; 142; 242) is delimited by a tubular wall (44; 144; 244) and that the water box and the expansion vessel are integral with being connected by a web (66; 166; 266) of material as well as tubular walls (68,74,78; 174; 274) forming the cylindrical passages communicating with each other.   between the water box and the expansion tank.   3. Device according to one of claims 1 and 2, characterized   in that it comprises a liquid inlet pipe (34) which opens directly into the water box (20) and in that the communication passages comprise a large bore (66) located close to the tubing arrival of liquid (34) and   several passages of smaller caliber (72,76).   4. Device according to claim 3, characterized in that it comprises a deflector (70) disposed in the water box (20) vis-à-vis the liquid inlet pipe (34), so that the large bore (66) opens into the water box in a region between the liquid inlet manifold (34) and the deflector (70).   5. Device according to one of claims 3 and 4, characterized   in that the water box (120) has an insulated compartment (38) which communicates with the expansion tank (42) via a small bore (76) and which on the other hand , is adapted to communicate with a lower water box (14) via   at least one tube (16 ') of the beam.   6. Device according to one of claims 1 and 2, characterized   in that it comprises a liquid inlet pipe (134) which opens directly into the expansion tank (142) and in that the communication passages are passages (172) of the same caliber, the total section of which is at least equal to the section of the tubing (134).   7 Device according to claim 6, characterized in that it comprises a deflector (170) disposed in the expansion vessel (142) near the liquid inlet pipe (134) and oriented to the top.   8 Device according to claim 6, characterized in that the liquid inlet tubing (134) is integral with a lid (150) attached to an open face (148) of the vase Expansion (142).   9 Device according to one of claims 1 and 2, characterized   in that it comprises a liquid inlet pipe (234) which opens directly into the expansion tank (242) and in that the water box (220) comprises a partition (240) dividing it into two compartments , one of which (236) communicates with the expansion vessel via the communication passages (272) and the other (236 ') communicates with a tubing of output (280).   10. Heat exchanger comprising a bundle (12; 112; 212) of vertical tubes provided at its upper end with a device   (10; 110; 210) according to one of claims 1 to 9 and, at its   lower end, a lower water box (14; 114; 214).