EP0532416B1 - Header box with an expansion chamber for a heat-exchanger with a bundle of vertical tubes, and heat-exchanger having such a device - Google Patents

Description

The invention relates to a water box and expansion tank device for a vertical tube bundle heat exchanger, and a heat exchanger comprising such a device.

Devices of this type are already known which include a generally horizontal water box, delimited by an open face wall suitable for being connected to the bundle of tubes by being mounted at the upper end of the bundle, as well as a vessel expansion generally horizontal arrangement, delimited by a tubular wall and placed above the water box communicating with it via a multiplicity of passages.

The lower end of the bundle is then suitable for receiving another water box, or lower water box, to ensure the circulation of a liquid which enters the heat exchanger through an inlet pipe and which leaves this exchanger heat through an outlet pipe. In most cases, the inlet tubing depends on the water box and expansion tank device while the outlet tubing depends on the lower water box.

Devices of this kind, which constitute a water box with an integrated expansion tank, are used in particular in heat exchangers intended to ensure the cooling of a motor vehicle engine by means of a liquid, generally of the glycol water, which circulates in a closed circuit and which is cooled by heat exchange with air passing through the bundle of tubes.

Already known from documents FR-A-2 395 397 and US-A-3 939 901, devices of this kind in which a single passage is provided, making the water box and the expansion vessel communicate 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 tank.

In the aforementioned devices, the single passage ensuring communication between the water box and the expansion tank consists of a tube which depends on a separating wall and which projects upwards in the expansion tank.

It is also known from document FR-A-2 548 379 to have communication passages in the upper part of the partition separating the expansion tank and the water box.

These known solutions are not satisfactory because they do not allow optimal expansion of the liquid within the device. In addition, they do not allow good degassing of the liquid because the bubbles, possibly present in the water box, must gather in a single place so that they can then be evacuated to the expansion tank.

In addition, the aforementioned known devices are formed from a large box in which there is a partition providing the single communication passage, to thus delimit a lower compartment constituting the water box itself and an upper compartment constituting the expansion tank. Because this known solution uses a large-sized housing, it has the major drawback of not allowing satisfactory pressure withstand.

The object of the invention is in particular to overcome the aforementioned drawbacks.

The invention proposes for this purpose a water box and expansion tank device for a heat exchanger with bundles of vertical tubes, comprising a water box, generally horizontal in layout, delimited by a wall with an open face suitable for being connected to the bundle of tubes by being mounted at the upper end of the bundle, an expansion tank, generally horizontal, delimited by a tubular wall and placed above the water box communicating with it via of a multiplicity of passages, the water box and the expansion tank being in one piece being connected by a web of material as well as by tubular walls forming the passages communicating between the water box and the expansion tank, characterized in that the communication passages are distributed over the length of the box.

Therefore, the water box and the expansion tank communicate with each other by a multiplicity of passages, which facilitates the exchange of fluid within the device itself.

In this way, good compensation is obtained for variations in liquid within the device and at the same time excellent degassing since the gas bubbles which may be present in the water box can be evacuated to the expansion tank by means of several passages distributed over at least part of the length of the water box.

In addition, the device can be made in one piece by molding a suitable plastic.

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 caliber passage located close to the liquid inlet pipe and several smaller passages.

The passage of large caliber is mainly intended to ensure a communication of liquid between the water box and the expansion tank, while the passages of smaller caliber are mainly intended for degassing for the evacuation of gas bubbles possibly present in the water box.

Advantageously, the device then comprises a deflector arranged in the water box opposite the liquid inlet tubing, so that the large caliber passage opens into the water box in a region between the tubing. inlet and deflector.

This deflector contributes to good communication between the water box and the expansion tank and in particular makes it possible to reduce the duration of degassing.

In this first embodiment of the invention, provision is made for the water box to house an insulated compartment which, on the one hand, communicates with the expansion vessel through one of the small caliber passages and which, d on the other hand, is able to communicate with a lower water box via at least one tube of the bundle.

At least one tube is then obtained which is isolated from the other tubes of the bundle and which makes it possible to ensure direct communication of the expansion vessel with the lower water box.

In a second embodiment of the invention, the device comprises a liquid inlet pipe which opens directly into the expansion tank, the communication passages being passages of the same caliber, the total section of which is at least equal to the section of the liquid inlet tubing.

This solution makes it possible to minimize the pressure drop undergone by the liquid.

In this second embodiment of the invention, the device advantageously comprises a deflector arranged in the expansion tank near the inlet pipe and oriented upwards, which facilitates degassing of the liquid.

Advantageously, the liquid inlet pipe is secured to a cover 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 of which 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 tank through the the aforementioned communication passages and the other of which communicates with an outlet pipe.

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

• la figure 1 est une vue en coupe longitudinale d'un dispositif de boîte à eau et de vase d'expansion selon la première forme de réalisation précitée et monté à l'extrémité supérieure d'un faisceau de tubes, la vue en coupe étant prise suivant la ligne I-I de la figure 2;
• la figure 2 est une vue en coupe prise suivant la ligne II-II de la figure 1;
• la figure 3 est une vue en coupe d'un échangeur de chaleur comprenant un dispositif de boîte à eau et de vase d'expansion conforme aux figures 1 et 2;
• la figure 4 est une vue en coupe longitudinale d'un dispositif de boîte à eau et de vase d'expansion selon la seconde forme de réalisation de l'invention;
• la figure 5 est une vue en coupe longitudinale d'un échangeur de chaleur comprenant un dispositif de boîte à eau et de vase d'expansion selon la figure 4; et
• la figure 6 est une vue en coupe d'un échangeur de chaleur comprenant un dispositif de boîte à eau et de vase d'expansion selon la troisième forme de réalisation de l'invention.

In the description which follows, given solely by way of example, reference is made to the appended drawings, in which:

• Figure 1 is a longitudinal sectional view of a water box and expansion tank device according to the first embodiment mentioned above and mounted at the upper end of a bundle of tubes, the sectional view being taken along 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 tank device according to Figures 1 and 2;
• Figure 4 is a longitudinal sectional view of a water box and expansion tank 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
• Figure 6 is a sectional view of a heat exchanger comprising a water box and expansion tank device according to the third embodiment of the invention.

First of all, reference is made to FIGS. 1 to 3 which represent a water box and expansion tank device 10 intended to be mounted horizontally at the upper end of a vertical bundle 12, the lower end of which is connected to a lower water box 14 (Figure 3).

The bundle 12 comprises a multiplicity of parallel tubes 16 arranged in two layers (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 tubes of the bundle.

The device 10 comprises a water box 20 with a generally horizontal arrangement comprising a wall 22 having an open rectangular face delimited by a peripheral rim 24 allowing the mounting, in a manner known per se, of the water box 20 on a collector 26 , also called "hole plate". This manifold comprises a multiplicity of holes 28 intended to be crossed respectively by the upper ends of the tubes 16 of the bundle.

The wall 22 assumes, in cross section, the general shape of an inverted U whose height increases from an end wall 30 to an opposite end wall 32 on which depends a liquid inlet pipe 34. The wall 22 thus defines, in combination with the walls 30 and 32, a chamber 36 which, on the one hand, communicates with the tube 34 and, on the other hand, with the tubes 16 of the bundle. 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 manifold 26. The compartment 38 communicates with at least one tube of the bundle, in the example with two tubes referenced 16 ′ to distinguish them from the rest of the tubes 16.

The device 10 further comprises an expansion vessel 42 with a generally horizontal arrangement located above the water box 20. The expansion vessel 42 is limited by a tubular wall 44, the height of which varies from a bottom wall 46 disposed close to the bottom wall 32 of the water box 20 to an open face 48 arranged close to 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 inside the expansion vessel in a stilling chamber 54 delimited by a wall 56 depending on the cover 50 and provided with an opening 58.

The tubular wall 44 includes a filling base 60 closed by a calibration plug 62. The wall 44 thus defines, in combination with the bottom wall 46 and the cover 50, an internal chamber 64 intended to ensure the 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. The wall 22 of the water box 20 and the wall 44 of the expansion vessel 42 are connected together by a web of material 66a which is interrupted from place to place to provide a certain number of communication passages between the chamber 64, on the one hand, and chambers 36 and 38, on the other.

Thus, the device comprises a communication passage 66 of large caliber disposed close to the outlet of the tubing 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 deflector 70 (FIG. 1) which is located opposite the inlet pipe 34, so that the passage 66 opens out between the tubing 34 and the deflector 70.

The device 10 further comprises four communication passages 72 distributed over 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 tubular cylindrical wall 74 which connects the walls 22 and 44.

Furthermore, the device comprises a communication passage 76 of caliber 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.

The lower water box 14 (FIG. 3) communicates with all the tubes of the bundle and it has an outlet pipe 80.

The heat exchanger shown in Figure 3 operates as follows. The heat exchanger receives a liquid to be cooled, for example glycol water coming from the cooling circuit of a motor vehicle engine. The liquid enters the chamber 36 of the water box 20 via the inlet pipe 34. This liquid then reaches the lower water box 14 via the tubes 16, as indicated by the arrows F. The liquid then leaves the lower water box 14 through the outlet pipe 80.

The variations in volume of the liquid are absorbed by the chamber 64 of the expansion vessel 42. The excess liquid enters the chamber 64 mainly through the passage 66 of large caliber while the passages 72 are used essentially for degassing the liquid. The gas bubbles possibly contained in the chamber 36 can gather in various places along the wall 22 to be evacuated in the chamber 64 of the expansion vessel via 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 tube 34 are captured by the deflector 70 and oriented towards the passage 66. The liquid circulating in the chamber 64 of the expansion tank gains the lower water box 14 via the passage 76, the insulated chamber 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 numbers increased by 100.

The device 110 of FIGS. 4 and 5 comprises a water box 120 with a generally horizontal arrangement delimited by a wall 122 of curved shape and by two bottom walls 130 and 132 together forming a rim 134a of rectangular outline for the assembly of a collector 126. The wall 132, which is higher than the wall 130, receives a level detector 152 which extends in a stilling chamber 154 delimited by a wall 156 which is connected to the wall 122 and which extends in direction of the collector, without however coming to touch it. The wall 122 and the walls 130 and 132 together define a chamber 136 communicating with all of the tubes 16 of the bundle 12.

The device 110 further comprises an expansion tank 142 which extends horizontally above the water box 130 and which is delimited by a tubular wall 144, by a bottom wall 146 arranged close to the wall 132 and by a cover 150 attached to an open face 148 of the wall 144. From the cover 150 depend, on one side, a liquid inlet pipe 134 and, on the opposite side, a deflector 170 which extends inside room 164 and which is directed upwards. Furthermore, the wall 144 receives a filling base 160 closed by a calibration plug 162. The walls 122 and 144 are connected by a web of material 166 and by the respective tubular walls 174 of four communication passages 172. The passages of communication 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 tubing 134 so that the pressure drop is minimal. As shown in FIG. 5, the device 110 is mounted at the upper end of a bundle 112, formed of tubes 116 and fins 118, the lower end of which communicates with a water box 114 provided with a tube. 180.

The exchanger of Figure 5 operates as follows. The liquid enters the chamber 164 of the expansion vessel via the inlet pipe 134. The gases possibly present in the liquid tend to be deflected upward by the deflector 170. The liquid then reaches the chamber 136 from the water box 120 via the four passages 172 and from there reaches the lower water box 114 via the set of tubes 116 of the bundle, to then be evacuated by the outlet pipe 180.

In the embodiment of FIG. 6, to which reference is now made, elements similar to those of FIG. 1 are designated with the same reference numbers increased by 200.

The device 210 comprises a water box 220 with a generally horizontal arrangement 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 bundle 212 formed of tubes 216 and fins 218. The lower end of the bundle communicates with a lower water box 214, which does not have an outlet pipe.

From the wall 222 hangs a partition 240 which seals against the manifold 226, so as to provide two separate chambers 236 and 236 ′ communicating respectively with two halves of the bundle 212.

The device 210 further comprises an expansion tank 242 disposed horizontally and above the water box 220. The expansion tank 242 is delimited by a tubular wall 244 attached to the wall 222 by a web of material 266, as well as by an end wall 246 and a cover 250 attached to an open face 248 of the wall 244. From the cover 250 depends a base 260 closed by a calibration plug 262.

In the embodiment of FIG. 6, the entry of the liquid takes place via an inlet pipe 234 connected laterally to the wall 244 near the bottom wall 246.

Furthermore, the water box 220 includes an outlet pipe 280 which communicates with the compartment 236 ′.

The expansion vessel delimits a chamber 264 which communicates with the chamber 236 of the water box by means of three calibrated passages 272 distributed over part of the length of the water box and of the expansion vessel. These three 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 for that the pressure drop is minimal. Thus, in the case of the heat exchanger of Figure 6, the liquid enters the chamber 264 of the expansion tank 242 through the inlet pipe 234 and then reaches the compartment 236 of the water box 220 by l 'intermediate passages 272. The liquid then reaches the lower water box 214 by one half of the tubes 216 of the bundle 212 and, from there, gains the chamber 236 ′ by the other half of the tubes of the bundle. The liquid then leaves the water box through the outlet pipe 280. In the heat exchanger of FIG. 6, one obtains a circulation of the fluid in two passes of opposite directions (circulation in U) and not a circulation in a single pass (circulation in I) as 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 then being closed by an attached cover 50, 150 or 250 .

The water box and expansion tank device of the invention finds particular application in heat exchangers used for cooling internal combustion engines for motor vehicles.

Claims (9)

1. A combination of a header and an expansion chamber for a heat exchanger having bundles (12; 112; 212) of vertical tubes (16; 116; 216), comprising a header (20; 120; 220), disposed generally horizontally and bounded by a wall (22; 122; 222) having an open face adapted to be connected to the bundle of tubes by being mounted at the upper end of the bundle (12; 112; 212), an expansion chamber (42; 142; 242), disposed generally horizontally, bounded by a tubular wall (44; 144; 244) and located above the header, communicating with the latter through a multiplicity of passages (66, 72, 75; 172; 272), the header and the expansion chamber being in monobloc form, being joined together by means of an integral baffle (66a; 166; 266) and by tubular walls (68, 74, 78; 174; 274) defining passages which communicate between the header and the expansion chamber, characterised in that the communication passages (66, 72, 76; 172; 272) are spaced apart over the length of the header.
2. A combination according to Claim 1, characterised in that it includes a tubular liquid inlet connector (34) which is open directly into the header (20), and in that the communication passages include a passage (66) of wide aperture, which is situated close to the tubular liquid inlet connector (34), together with a plurality of passages (72, 76) of smaller aperture.
3. A combination according to Claim 2, characterised in that it includes a deflector (70) disposed in the header (20) in facing relationship with the tubular liquid inlet connector (34) so that the passage (66) of wide aperture is open into the header in a region lying between the tubular liquid inlet connector (34) and the deflector (70).
4. A combination according to Claim 2 or Claim 3, characterised in that the header (120) defines an isolated compartment (38) which, firstly, communicates with the expansion chamber (42) through a passage (76) of small aperture, and which, secondly, is adapted to communicate with a lower header (14) through at least one tube (16') of the bundle.
5. A combination according to Claim 1, characterised in that it includes a tubular liquid inlet connector (134) which is open directly into the expansion chamber (142), and in that the communication passages are passages (172) of the same aperture, the total cross section of which is at least equal to the cross section of the tubular liquid inlet connector (134).
6. A combination according to Claim 5, characterised in that it includes a deflector (170) disposed in the expansion chamber (142) close to the tubular liquid inlet connector (134) and orientated upwardly.
7. A combination according to Claim 5, characterised in that the tubular liquid inlet connector (134) is fixed to a cover member (150) which is fitted on an open face (148) of the expansion chamber (142).
8. A combination according to Claim 1, characterised in that it includes a tubular liquid inlet connector (234) which is open directly into the expansion chamber (242), and in that the header (220) includes a wall (240) which divides it into two compartments, one of which (236) communicates with the expansion chamber through communication passages (272), with the other chamber (236') communicating with a tubular outlet connector (280).
9. A heat exchanger comprising a bundle (12; 112; 212) of vertical tubes having, at its upper end, a combination (10; 110; 210) according to one of Claims 4 to 8 and, at its lower end, a lower header (14; 114; 214).

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