EP2042704B1 - Degassing unit equipped with a plunger tube and a settling chamber - Google Patents

Abstract

The tank (1) has a closed enclosure delimiting a plenum chamber (2) and a chamber (3). The plenum chamber has a liquid outlet (5) emerging into the chamber (3). The outlet is placed in a lower point of the plenum chamber. The outlet is located immediately near a discharge end (10) of an immersion pipe (7) in the plenum chamber and near a liquid evacuation outlet (6) of the chamber (3) outside the tank. The pipe is emerged into the lower point of the plenum chamber. The outlet is provided in a surface (12) that forms a base of the chamber (3).

Description

The present invention generally relates to liquid degassing boxes of liquid circulation circuit.

The invention more particularly relates to a box for degassing liquid from a liquid circulation circuit, in particular an internal combustion engine cooling circuit, said box comprising a closed enclosure delimiting at least two communicating chambers which comprise, one, said first plenum chamber, at least one liquid supply inlet, said supply inlet being in the form of a plunger tube opening at the bottom of said first chamber, the other, said second chamber, at least a liquid discharge outlet outside the degassing box, said exhaust outlet being formed in the bottom face of said second chamber.

Examples of such degassing boxes are described in the patents FR-2841187 , FR-2890109 and DE 202 17 307 .

In motor vehicles, the degassing box is an important part of the cooling system. Indeed, it ensures the separation of gases, in particular air, which is in solution in the liquid and whose presence in the cooling circuit is detrimental to its proper operation. This degassing box, by its reservoir function, also constitutes a reserve capacity to compensate for the losses by micro-leaks of the circuit, in particular by lack of sealing of the various connections whose circuit is provided. It also constitutes an expansion volume capable of absorbing the expansions of the coolant as a function of the temperature and pressure conditions. It is also used for filling the circuit and checking the level of the coolant. Finally, it ensures the loading and the pressurization of the cooling circuit, this pressurization being regulated by a shutter plug acting as a calibrated valve.

In recent years, the degassing function of such a degassing box, playing the role of expansion tank and degassing, has been widely explored. Generally, in the traditional expansion and degassing tanks, the separation of the gaseous and liquid phases is done under the effect of gravity, the buoyancy of Archimedes causing the lighter gases to rise above the liquid to the surface of the latter. in the upper part of the tank as illustrated in particular by the patent application WO 2004/001204 . The degassing boxes are therefore all provided with an enclosure defining, on the one hand, a gaseous phase corresponding to the space left free and containing air in the upper part of the enclosure, and, on the other hand, part, a liquid phase, corresponding to the lower part of the enclosure.

Document is known FR 2.866.064 , belonging to the applicant, a degassing box as described above which comprises a plenum and a plunger opening at the bottom of the plenum so as to limit the emulsion of the incoming liquid and to promote degassing said liquid. The plenum, inside which opens the plunger tube, has several functions. It makes it possible to prevent the liquid leaving the enclosure from the evacuation outlet, also called the loading port of the circuit, from being in a state of excessive turbulence. It also makes it possible to avoid the opening of the opening of the plunger tube as a result of the movements of the liquid caused by an acceleration of the vehicle during the driving of the latter and consequently a suction of air. The use of a dip tube limits the emulsion of the liquid entering the upper part of the degassing box. Indeed, without a dip tube, the liquid, on the one hand, would lead directly into the gaseous phase located in the upper part of the degassing box, and, on the other hand, fall in the lower part with a cascade effect, which cause the emulsion of the liquid.

With a degassing box as described in the document FR 2.866.064 , the incoming liquid passes from the plenum to the outlet evacuation of the second chamber by overflow of the plenum. However, the liquid supply of the second chamber by overflow of the plenum requires a large volume of liquid in the degassing box to ensure that the discharge outlet is permanently fed with liquid even when the box of degassing is inclined under normal vehicle operating conditions or when the degassing box is shaken.

Today, it is desired to reduce the volume of liquid required in the cooling circuit.

In addition, during the overflow of the second chamber, the liquid that passes into the second chamber is partially charged with gas, which decreases the degassing efficiency of the degassing box.

The present invention aims to limit the volume of liquid in the degassing box, while ensuring, on the one hand, the continuous supply of the exhaust outlet of the second chamber and, on the other hand, a effective degassing of the liquid within the degassing box.

To this end, the invention relates to a liquid-circulation circuit liquid degassing box, in particular an internal combustion engine cooling circuit, said box comprising a closed enclosure delimiting at least two communicating chambers which comprise, one, said first plenum chamber, at least one liquid supply inlet, said supply inlet being in the form of a plunger tube opening at the bottom of said first chamber, the other, said second chamber, at least one liquid discharge outlet outside the degassing box, said discharge outlet being formed in the bottom face of said second chamber, characterized in that said first plenum comprises at least one outlet of liquid opening into said second chamber and disposed at a low point of said first plenum, said at least one exit being located in the immediate vicinity, on the one hand, the outlet of the dip tube in said first chamber and, secondly, the liquid discharge outlet of the second chamber outside the degassing box.

The outlet of the plenum and the discharge outlet of the degassing box being disposed, on the one hand, in the immediate vicinity of one another and, on the other hand, at the bottom of the degassing box , said outlets are continuously immersed even when the degassing box is inclined during operation of the vehicle or during shaking. It is thus not necessary to have a large volume of liquid in the degassing box to ensure that the discharge outlet is continuously supplied with liquid by the outlet of the plenum, which allows a reliable operation of the engine cooling circuit.

In addition, thanks to the arrangement of the outlet of the plunger tube in the immediate vicinity of the discharge outlet of the degassing box, the outlet of the plunger tube is also immersed permanently, which reduces the risk of liquid emulsion and promotes degassing said liquid, without the need to provide a large volume of liquid.

Thus, the volume of liquid in the degassing box can be reduced compared to a degassing box of the state of the art, while ensuring, on the one hand, the continuous supply of the exhaust outlet of the degassing box and, on the other hand, effective degassing of the liquid within the degassing box.

According to a first advantageous characteristic of the invention, said first plenum chamber, which has a cross section of dimension smaller than the cross section of the second chamber, affects the shape of a column.

The first plenum chamber is thus dimensioned so that the level of the liquid in said first plenum chamber is greater than the level of liquid in the second chamber which is provided with the exhaust outlet, which promotes the continuity of the liquid supply of the exhaust outlet of the second chamber.

In addition, thanks to its small cross-section, the plenum-shaped plenum is filled with a small volume of liquid, which favors the immersed retention of said outlet of the plunger tube and the outlet of the chamber of tranquilization.

According to another advantageous characteristic of the invention, the first and the second chambers, separated from one another by a wall at the base of which the liquid outlet of the first chamber in the second chamber is formed, are suitable to communicate with each other by overflow of the contents of the first chamber to the second chamber, the partition wall between the first and the second chamber being equipped, on the side of the second chamber, means for deflecting the liquid from an overflow of the content of the first chamber to the second chamber, these deflection means imposing the liquid poured into said second chamber, a circulation path inside the second chamber, before evacuation of said second chamber through the orifice discharge.

According to another advantageous characteristic of the invention, the outlet of the dip tube in the first chamber, formed by the free end of said dip tube, is beveled, the bevel being oriented in a direction opposite to that leading to the exit of said first still room.

The beveled shape of the outlet of the plunger tube makes it possible to generate in the first plenum chamber a laminar and homogeneous liquid flow promoting the circulation of the liquid. In addition, the particular orientation of said bevel, in the opposite direction to the outlet of the first plenum chamber, makes it possible to circulate the liquid in the plenum and thus to improve the degassing of said liquid.

According to another advantageous characteristic of the invention, the plunger tube is provided at the top with an additional fluid supply orifice of the first chamber.

According to another advantageous characteristic of the invention, said first plenum comprises at least one other liquid supply inlet, called lower supply inlet, located in the lower part of said first plenum chamber.

According to another advantageous characteristic of the invention, said lower feed inlet opens into the first chamber at the same level as the outlet of the dip tube and, preferably, substantially to the right of the outlet of the dip tube.

According to another advantageous characteristic of the invention, at least a portion of the contour of the outlet of the plenum chamber is delimited by the bottom face of the degassing box.

According to another advantageous characteristic of the invention, the liquid outlet of the first chamber, opening into the second chamber, is formed by a calibrated drain orifice maintaining the level of the liquid in the first chamber above the level of the outlet of the first chamber. dip tube in said first chamber.

According to another advantageous characteristic of the invention, the degassing box is formed by assembling two superposed parts.

• la figure 1 est une vue en perspective de l'intérieur de la partie inférieure de la boîte de dégazage ;
• la figure 2 est une vue en coupe partielle de la boîte de dégazage montrant notamment l'agencement du tube plongeur et de la chambre de tranquillisation ;
• la figure 3 est une vue en perspective de l'intérieur de la partie supérieure de la boîte de dégazage.

The invention will be better understood on reading the following description of exemplary embodiments, with reference to the appended drawings in which:

• the figure 1 is a perspective view of the interior of the lower part of the degassing box;
• the figure 2 is a partial sectional view of the degassing box showing in particular the arrangement of the dip tube and the chamber of tranquilization;
• the figure 3 is a perspective view of the inside of the upper part of the degassing box.

To the figure 1 , there is shown a liquid degassing box 1 of liquid circulation circuit, in particular of internal combustion engine cooling circuit. Said degassing box 1 comprises a closed chamber delimiting at least a first chamber 2 and a second chamber 3.

The body of the degassing box 1 is composed of an outer envelope, preferably of substantially spherical or cylindrical shape with a spherical bottom. This body is formed of two half-shells 1A, 1B assembled by a joint plane generally coincides with the horizontal in the mounted state of the degassing box 1. The degassing box body 1 further comprises walls and / or portions of walls made in one piece with said envelope and serving to delimit said chambers 2, 3.

As represented in figures 2 and 3 the first chamber 2, called the first plenum chamber, has a liquid supply inlet 4, called the upper supply inlet. Said feed inlet 4 is in the form of a dip tube 7 opening at the bottom of said first plenum chamber 2. The liquid supply inlet 4 protrudes outside of said degassing box, in the upper part, to be connected to an element of the engine cooling circuit of the vehicle, such as the radiator of the vehicle. The second chamber 3 comprises an outlet 6 for discharging the liquid outside the degassing box 1. This outlet 6 is formed in the face 12 forming the bottom of said second chamber 3.

The first chamber 2 is formed by a partitioning structure comprising a partition wall having a central portion 14 and two so-called lateral portions 15, 16. The partition wall is disposed opposite and at a distance from the dip tube 7. This partition wall , vertical appearance, originates on the inner face 12 of the wall of the half-shell 1A lower and extends towards the inner face of the upper half shell 1B. The lateral portions 15, 16 of the partition wall are disposed on either side of the central portion 14 and cooperate with the latter to remotely surround the plunger tube 7 so as to form a column-type chamber around said dip tube 7.

In a manner characteristic of the invention, said first plenum chamber 2 comprises a liquid outlet 5 opening into said second chamber 3 and disposed at a low point of said first plenum chamber 2. Said outlet 5 is situated in the immediate vicinity, on the one hand, of the outlet 10 of the plunger tube and, on the other hand, of the liquid outlet outlet 6 of the second chamber 3 outside the degassing box. 1. "Immediate vicinity" means that said outlet 5 is located near and substantially at or above the outlet 10 of the plunger tube and the discharge outlet 6. Here, the level, or height, is the distance from the bottom face of the degassing box

Thanks to such an arrangement of the outlet 5 of the plenum chamber 2 with the outlet 6 of the second chamber 3 and the outlet 10 of the plunger tube 7, said outlets 5, 6 and the outlet 10 of the plunger tube 7 are kept immersed in permanence for a limited volume of liquid in the degassing box. The term "permanently" immersed means that said outlets 5, 6 and outlet 10 of the plunger tube are immersed under the normal operating conditions of the vehicle equipped with said degassing box, as well as during shaking and during operation. complete stopping of said vehicle. Thus, the volume of liquid in the degassing box can be reduced compared to a degassing box of the state of the art, while ensuring, on the one hand, the continuous supply of the exhaust outlet of the second chamber and, on the other hand, effective degassing of the liquid within the degassing box.

As represented in figures 2 and 3 , the plunger tube 7 is a bent tube formed of a first portion 17, which extends substantially parallel to the plane of the face 12 forming the bottom of the degassing box 1, and a second portion 18 carrying the outlet 10 which extends substantially parallel to the partition wall of the two chambers 2, 3.

Said first plenum chamber 2, which has a cross section smaller in size than the cross section of the second chamber 3, has the shape of a column. Cross section means a section in a plane substantially parallel to the face 12 forming the bottom of the degassing box 1, that is to say in a plane substantially transverse to the vertical axis of the corresponding chamber. In addition, the term "column" means a chamber whose height has a value greater than the dimensions of width and length. Thus, for the same volume of liquid in each chamber 2, 3, the liquid height is greater in the first plenum chamber 2, which allows the outlet 10 of the plunger tube 7 to be immersed permanently, even at room temperature. inclined condition of the degassing box 1 for normal operation of the vehicle or during shaking.

The liquid outlet 5 from the first chamber 2 to the second chamber 3 is formed at the base of the main portion 14 of the partition wall of the first and second chambers 2, 3. As illustrated in FIG. figure 3 , the liquid outlet 5 of the first chamber 2, opening into the second chamber 3, is formed by a calibrated discharge orifice 5 to maintain the level of the liquid in the first chamber 2 above the level of the outlet 10 of the dip tube 7 in said first chamber 2. Thus, by playing in its design on the dimensions of this outlet 5, it is possible to regulate the passage of the liquid from the plenum chamber 2 to the second chamber 3 while ensuring, thanks to the in column form of said chamber 2, a level of liquid always greater in the plenum chamber 2 than in the second chamber 3. In the example illustrated in FIG. figure 3 , the outlet 5 of said first plenum chamber 2 has a dimension substantially equal to that of the evacuation outlet 6 of the second chamber 3, and the outlet 5 is turned towards the outlet 6. Alternatively, it could be provided that the exit 5 of the first room 2 of tranquilization does not is not oriented towards the discharge outlet 6, so as to allow a circulation of the liquid leaving the outlet 5 before it is discharged through the outlet 6. It could also provide to have around a portion of the outlet 6 a deflection wall of low height and oriented vis-à-vis the outlet 5 so as to impose a circulation to the liquid before discharge. Such circulation of the liquid promotes its degassing and the low height of the deflection wall does not prevent the permanent immersion of the outlets 5 and 6.

In addition, the orifice 5 forming the outlet of the plenum also makes it possible to generate pressure drops which reduce the turbulence of the flow of the liquid from the plenum chamber 2 to the second chamber 3.

As illustrated more particularly in figure 1 the first and second chambers 2, 3 are also able to communicate with one another by overflowing the contents of the first chamber 2 towards the second chamber 3. In fact, the lateral portions 15, 16 of the separation wall are of decreasing height from the center of the degassing box to the casing of the enclosure of said degassing box, which allows the liquid of the first chamber 2 to overflow over said lateral portions 15, 16 of the partition wall. Such a design of the chamber 2 of tranquilization, allowing an overflow of liquid to the second chamber 3, makes reliable the operation of the degassing box 1 in case of too fast filling of the chamber 2 of tranquilization. In the example shown in the figures, the main part 14 does not extend to the ceiling face of the degassing box 1. Alternatively, it could be provided to extend the main portion 14 to the ceiling face of the degassing box.

As illustrated in figure 1 the separating wall between the first and the second chamber 2, 3 is also equipped, on the side of the second chamber 3, with deflection means 8 for the liquid coming from an overflow of the contents of the first chamber 2 towards the second chamber 3. These deflection means 8 impose on the liquid poured into said second chamber 3, a circulation path inside the second chamber 3 before evacuation of said second chamber 3 through the orifice 6 evacuation.

These deflection means are here in the form of fins 8 which are oriented radially to the axis of the column 2. These fins 8 are arranged at the base of the partition wall by pressing on the face 12 forming a bottom . The fins 8 are deflection means in the sense that, when the liquid overflows over the partition wall of the first and second chambers 2, 3 to pass into said second chamber 3, the liquid is not directed directly to the orifice 6 for evacuating the second chamber 3 but is deflected by the fins 8 before reaching the evacuation orifice 6 of the second chamber 3, which makes it possible to break the turbulence of the flow of this liquid.

As illustrated in figure 3 , the outlet 10 of the plunger tube 7 in the first chamber, formed by the free end of said plunger tube is beveled. This bevel is oriented in a direction opposite to that leading to the outlet 5 of said first chamber 2 of tranquilization.

The plunger tube 7 is provided at the top with an additional orifice 9 for supplying fluid to the first chamber 2 (see FIG. figures 2 and 3 ). The additional orifice 9 is located on the elbow of the plunger tube 7 on the side of the second portion 18 of the plunger tube 7 and substantially at the height of the first portion 17. Due to the presence of this additional orifice 9 opening into the space left free of the enclosure corresponding to the gaseous phase of this chamber, it results the possibility, by means of this flow of liquid, to heat the air contained in the enclosure and thus increase the expansion of the air , which favors the pressurization of the circuit. Furthermore, through this additional orifice, a first degassing phase is obtained, this degassing then being completed when the flow of liquid opens into the chamber through the opening of the plunger tube.

As represented in Figures 1 to 3 said first plenum chamber 2 comprises at least one other liquid supply inlet 11, called the lower supply inlet, located in the lower part of said first plenum chamber 2. Said lower feed inlet 11 protrudes outside of said degassing box so as to be connected to another element of the engine cooling circuit of the vehicle, such as the cylinder head of the vehicle engine.

Said lower feed inlet 11 opens into the first chamber 2 at the same level as the outlet 10 of the dip tube 7 and, preferably, substantially to the outlet 10 of the plunger tube 7. The liquid from the inlet 11 of inferior supply will then meet the outlet 10 of the plunger tube 7, which will prevent it from leaving directly through the outlet 5 of the plenum chamber 2, said liquid to bypass the outlet 10 of the plunger tube 7 to reach said outlet 5. The turbulence of the liquid from this inlet 11 are thus reduced and the liquid, which must circumvent the outlet 10 of the plunger tube 7, has time to be degassed.

As illustrated more particularly in figure 3 at least a portion of the contour of the outlet 5 of the plenum chamber 2 is delimited by the face 12 forming the bottom of the degassing box. Such a design allows that said outlet 5 of the plenum chamber 2 is positioned as low as possible in the degassing box, which promotes the permanent immersion of the two outlets 5 and 6.

In the examples shown, the enclosure of delimitation of the enclosure of the degassing box 1 has a cylindrical shape with a spherical bottom and is preferably constituted by assembling at least two half-shells 1A, 1B connected between they by a plan of joint.

Thus, only two pieces to obtain a degassing box according to the invention. This envelope can be made in terms of synthesis from molded parts. The plenum may be molded with the casing of the box 1, in particular the lower half-shell 1A (see figure 1 ). This lower half-shell 1A also comprises, coming from molding, a liquid supply duct forming the so-called lower inlet 11, and an orifice forming the discharge outlet 6. The upper half-shell 1B has, for its part, come from molding, a conduit for supplying liquid from the radiator, forming the so-called upper inlet 4, and an opening 13 for filling made in the form of a threaded end piece projecting from outside the enclosure. This opening 13 is able to be closed by means of a shutter member, such as a plug, equipped with a calibrated valve. This opening 13 serves to fill the liquid circuit and allows pressurization of the circuit.

Claims (10)

1. A box (1) for degassing liquid from a circuit for circulating a liquid, in particular from a cooling circuit of an internal combustion engine, said box comprising a closed enclosure delimiting at least two communicating chambers (2, 3), one of which, so-called first tranquilization chamber (2), includes at least one inlet (4) for supplying liquid, said supply inlet (4) appearing as a plunger tube (7) opening out in the low portion of said first chamber, the other one of which, so-called second chamber (3), includes at least one outlet (6) for discharging the liquid outside the degassing box (1), said discharge outlet (6) being made in the face (12) forming the bottom of said second chamber (3),
   characterized in that said first tranquilization chamber (2) includes at least one outlet (5) for liquid opening out into said second chamber and positioned at a low point of said first tranquilization chamber (2), said at least one outlet (5) being located in close proximity to the mouth (10) of the plunger tube (7) in said first chamber (2) on the one hand, and to the liquid discharge outlet (6) of the second chamber (3) outside the degassing box (1), on the other hand.
2. The degassing box (1) according to claim 1, characterized in that said first tranquilization chamber (2), which has a cross-section of a smaller size than the cross-section of the second chamber, assumes the shape of a column.
3. The degassing box (1) according to any of claims 1 to 2, characterized in that the first and second chambers (2, 3), separated from each other by a wall at the base of which the outlet (5) is made for liquid from the first chamber (2) into the second chamber (3), are capable of communicating with each other by overflow of the contents of the first chamber (2) into the second chamber (3), the separation wall between the first and second chambers (2, 3) being equipped, on the side of the second chamber (3), with means (8) for deflecting the liquid from an overflow of the contents of the first chamber (2) towards the second chamber (3), these deflection means (8) imposing to the liquid poured into said second chamber (3), a circulation path inside the second chamber (3), before evacuation of said second chamber (3) via the discharge orifice (6).
4. The degassing box (1) according to any of claims 1 to 3, characterized in that the mouth of the plunger tube (7) in the first chamber, formed by the free end of said plunger tube, is bevelled, the bevel being oriented along a direction opposite to the one leading to the outlet (5) of said first tranquilization chamber (2).
5. The degassing box (1) according to any of claims 1 to 4, characterized in that the plunger tube (7) in the high portion is provided with an additional orifice (9) for supplying fluid to the first chamber (2).
6. The degassing box (1) according to any of claims 1 to 5, characterized in that said first tranquilization chamber (2) comprises at least one other liquid supply inlet (11), a so-called lower supply inlet, located in the low portion of said first tranquilization chamber (2).
7. The degassing box (1) according to claim 6, characterized in that said lower supply inlet (11) opens out into the first chamber (2) at the same level as the mouth of the plunger tube (7) and preferably substantially at right angles to the mouth (10) of the plunger tube (7).
8. The degassing box (1) according to any of claims 1 to 7, characterized in that at least one portion of the contour of the outlet (5) of the tranquilization chamber (2) is delimited by the face (12) forming the bottom of the degassing box.
9. The degassing box (1) according to any of claims 1 to 8, characterized in that the outlet (5) for liquid from the first chamber (2), opening out into the second chamber (3), is formed by a calibrated drain orifice (5) maintaining the level of the liquid in the first chamber (2) above the level of the mouth (10) of the plunger tube (7) in said first chamber (2).
10. The degassing box (1) according to any of claims 1 to 9, characterized in that it is formed by assembling two superposed portions (1A, 1B).

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