EP0261021A1 - Pressure vessel with liquid presence detector in a gas chamber - Google Patents

Abstract

It is a pressure tank of the type comprising, in an envelope (11), a separator (12) dividing said envelope into two chambers of variable volume, namely a liquid chamber (13) and a gas chamber. (14), with, immersing in the gas chamber (14), a sensor (20) sensitive to the presence of liquid. According to the invention, the sensitive end (22) of the sensor (20) is closer to the transverse wall (18) of the separator (12) than to the corresponding orifice of the envelope (11), and this sensor ( 20) is preferably constituted by an optical probe. Application, in particular, to pressure accumulators or transmitters.

Description

The present invention relates generally to pressure tanks, that is to say tanks capable of confining at least one fluid under pressure.

They can be both pressure accumulators and pressure transmitters.

The present invention relates more particularly to those of these pressure tanks which comprise, in an envelope, in practice an envelope of rigid material, a separator, which divides said envelope into two chambers of variable volume, namely a liquid chamber and a chamber. of gas, said envelope corollarily comprising, at a distance from each other, two orifices, namely a liquid orifice and a gas orifice, with which said liquid chamber and said gas chamber are each in communication respectively, and which, at least transversely with respect to said envelope, has a wall, called hereinafter for the sake of convenience, transverse wall, spaced both from one and from the other of said orifices and mounted movably in said envelope.

This separator can for example be constituted by a bladder of flexible material, the opening of which surrounds one of the two orifices, in practice the gas orifice; in this case, it is the bottom of this bladder which forms what is here agreed to be called the transverse wall of the separator.

As a variant, this separator can be constituted by a piston; in this case, it is this piston which forms the transverse wall, the separator reducing itself to such a transverse wall.

In all cases, the separator used is intended to isolate from one another the two fluids present within the pressure tank concerned, a gas on the one hand, and a liquid on the other hand.

However, in service, operational incidents can occur, which lead to a certain mixture of these two fluids, with, in particular, penetration of the liquid into the gas chamber.

For example, when the separator is a bladder, there can be a local rupture of this bladder, or, when the liquid in play is a chemical which is relatively aggressive with regard to its constituent material, it can intervene, over time, permeability of this bladder causing diffusion of this liquid through its wall.

Similarly, when the separator is a piston, there may be a leak between this piston and the envelope in which it is slidably mounted.

Most often, the corresponding fault is detected only afterwards, by the consequences which it does not fail to cause downstream, in the operating circuit to which the pressure tank concerned is connected.

When, as is frequently the case, several separate pressure tanks jointly serve a single circuit of use, it is not possible, moreover, to know, on the sole observation of the actual consequences downstream, that of these pressure tanks which is thus in default, and it is then necessary to systematically ensure a control of all of these.

To overcome these drawbacks, it has already been proposed to equip a pressure tank of the type in question with a sensor sensitive to the presence of liquid, by subjecting this sensor to the atmosphere of the gas chamber of this pressure tank. .

In the French patent filed on April 2, 1979 under No. 79 08195 and published under No. 2,422,055, this sensor is incorporated into the tubular plug controlling the gas orifice.

Such a provision has given and can still give satisfaction.

However, when, and this is in practice the most frequent case, the pressure tank is arranged vertically with its gas orifice upwards, the sensor thus implemented only intervenes when the gas chamber is completely invaded by the liquid, which, for the circuit of use concerned, may already be too late.

It is more or less the same when, as described in the French patent application filed on August 4, 1983 under No 83 12850 and published under No 2.531.754, the sensor, installed in favor of the tubular plug controlling the orifice gas, extends to a limited extent in the gas chamber from the latter.

In addition, in the latter case, the sensor used operating by capacitance or inductance, it has a non-negligible size, in particular in diameter, which can make it technically difficult to install, and, by its very principle, it requires a large volume of liquid before delivering a significant signal.

The present invention generally relates to a provision advantageously allowing, and in a particularly reduced diameter space, a much faster detection of a defect leading to penetration of liquid into the gas chamber.

More specifically, it relates to a pressure tank of the kind comprising, in an envelope having at a distance from each other two orifices, namely a liquid orifice and a gas orifice, on the one hand, a separator, which divides said envelope into two chambers of variable volume, namely a liquid chamber and a gas chamber, with which each of said orifices is respectively in communication, and which, at least transversely with respect to said envelope, has a wall, here called for simple convenience, transverse wall, spaced both from one and from the other of said orifices, and movably mounted in said envelope, and, on the other hand, a sensor sensitive to the presence of liquid, which, by means of an opening in the envelope in communication with the gas chamber, extends into said gas chamber, this pressure tank being in a way general characterized in that, at least for the resting configuration, when empty, of the transverse wall of the separator, the sensitive end of said sensor is closer to said transverse wall than to the orifice of the envelope through which it extends into the gas chamber.

Thus, the desired fault detection can take place much more quickly.

Preferably, the sensor is an optical probe comprising an optical conduit, which is itself formed of one or more optical fibers, and the internal end of the envelope forms the sensitive end, while its other end is intended to be in connection with a signal processing device, either in the immediate vicinity of the pressure tank, or largely at a distance therefrom.

Such an optical probe, known per se, thus finds a particularly satisfactory application to pressure reservoirs, on the one hand because of the relative elastic deformation capacity of the material usually constituting its optical conduit, and on the other hand because the very small overall dimensions of the latter.

Indeed, by the elastic deformation capacity of the optical conduit which it comprises, this optical probe is advantageously able to absorb by itself the displacements of the transverse wall of the separator as well when it is constituted by a bladder only when it is constituted by a piston.

Preferably, when the separator consists of a bladder, the optical probe is reduced to a section of optical conduit which, apart from the arrow of which it may be the object, is substantially rectilinear.

The installation of such an optical probe is thereby facilitated.

But its sensitive end is advantageously systematically in the lower part of the pressure tank, whether the latter is mounted vertically, or, due to the arrow that it can take by simple gravity, that it is mounted horizontally.

As a variant, when the separator consists of a piston, the optical probe used according to the invention preferably forms at least one helical turn, and, in the vicinity of its sensitive end, it is coupled, in practice by rotary means , said piston.

In all cases, and according to a development of the invention, the optical conduit that this optical probe comprises is preferably, over at least part of its length, jacketed by a sheath, and, for example, by a sheath made of material retractable, which, in addition to the protection provided, advantageously makes it possible to adjust the elastic deformation capacity in a suitable manner, in addition avoiding that it can take too sharp a curvature, detrimental to its longevity, upon entering the chamber of gas concerned.

Preferably also, and according to another development of the invention, the sensitive end of the optical probe thus forming the sensor used according to the invention is surrounded by a tubular cage, being disposed radially away from the wall lateral thereof and axially set back relative to its outlet.

This tubular cage advantageously protects the sensitive end of the probe during the manipulations necessary for the installation thereof, and it then advantageously protects it from any parasitic contact with the separator, which avoids the incidence of possible traces of liquid on the surface thereof, while leaving free access to said sensitive end for such a liquid when it is present in the gas chamber concerned other than in the form of such traces.

Thanks to the conjunction of such a cage and the sheath lining the optical conduit that comprises the optical probe implemented according to the invention, it is drawn a optimal use of the natural elastic deformation capacity, duly controlled by the sheath, of this optical conduit, this conjunction allowing the sensitive end of the optical probe to be effectively in the immediate vicinity of the transverse wall of the separator without, thanks at the cage, it results from any consequence of a possible contact with it.

This combination of means is therefore particularly favorable to the arrangement, according to the invention, of the sensitive end of this optical probe near the transverse wall of the separator.

At the same time, because of its very small diametrical size, in practice less than 2.5 mm, the implantation in a pressure tank, of the optical probe forming the sensor used according to the invention, is advantageously facilitated.

This characteristic is particularly favorable in the case where the separator of such a pressure tank is constituted by a bladder, because, the orifice of the envelope of this pressure tank in favor of which the optical probe is implanted then being very simply the gas orifice of this envelope, it makes it possible to be satisfied with the most common passage diameters that the valve body usually provides in the axially provided in such a gas orifice for inflating the bladder.

It results in particular that the sensor used according to the invention is suitable for both pressure tanks to be built as well as pre-existing pressure tanks, these advantageously being able to be thus, very simply, and at the lowest price , fitted with such a sensor if desired.

In practice, for its installation on a pressure tank, this sensor is preferably carried by a tubular plug suitable for controlling the orifice of the envelope of this pressure tank by means of which it must extend in the corresponding gas chamber.

But, according to the invention, in the case where the separator of the pressure tank concerned is a bladder, this installation is also advantageously done by means of an adapter body, which, at the ends, each respectively, of an axial channel, has, on the one hand, projecting, a tubular plug, by which it is adapted to be attached to such a pressure tank, and, more precisely, on the valve body usually fitted to the gas orifice of the envelope thereof, in substitution to the valve itself usually fitted with such a valve body, and, on the other hand, in a hollow, a bore, by which it is adapted to receive the tubular plug carrying the sensor to be put in place, said adapter body being by elsewhere adapted, by a transverse channel in communication with the preceding axial channel, to receive said valve.

This adapter body thus makes the positioning of the sensor particularly easy.

• la figure 1 est, à échelle réduite, une vue en élévation coupe d'un réservoir de pression équipé d'un capteur suivant l'invention ;
• la figure 2 est, à échelle supérieure, une vue en coupe axiale de ce capteur et du bouchon tubulaire qui le porte ;
• les figures 3, 4, 5 reprennent, à échelle encore supérieure, les détails de réalisation repérés par des encarts III, IV, V sur la figure 2 ;
• la figure 6 est une vue qui, analogue à celle de la figure 1, illustre l'intervention du capteur suivant l'invention ;
• la figure 7 est une vue qui, elle aussi analogue à celle de la figure 1, se rapporte à un autre mode d'orientation possible pour le réservoir de pression concerné ;
• la figure 8 est une vue en coupe axiale d'un corps adaptateur susceptible d'être mis en oeuvre pour le support du bouchon tublaire portant le capteur suivant l'invention ;
• la figure 9 est une vue en coupe transversale de ce corps adaptateur, suivant la ligne IX-IX de la figure 8 ;
• la figure 10 est, éclatée, une vue partielle en coupe axiale, illustrant, à l'échelle des figures 8 et 9, la mise en oeuvre de ce corps adaptateur ;
• la figure 11 est une vue analogue à celle de la figure 5, pour une variante de réalisation ;
• la figure 12 est une vue qui, analogue à celle de la figure 10, illustre le mode de fonctionnement de cette variante de réalisation ;
• la figure 13 est une vue qui, analogue à celle de la figure 7, se rapporte à un autre type de réservoir de pression.

The characteristics and advantages of the invention will become apparent from the description which follows, by way of example, with reference to the appended schematic drawings in which:

• Figure 1 is, on a reduced scale, a sectional elevation view of a pressure tank equipped with a sensor according to the invention;
• Figure 2 is, on a larger scale, an axial sectional view of this sensor and the tubular plug which carries it;
• Figures 3, 4, 5 show, on a still larger scale, the construction details identified by inserts III, IV, V in Figure 2;
• Figure 6 is a view which, similar to that of Figure 1, illustrates the intervention of the sensor according to the invention;
• Figure 7 is a view which, also similar to that of Figure 1, relates to another possible mode of orientation for the pressure tank concerned;
• Figure 8 is an axial sectional view of a body adapter capable of being used for the support of the glass plug carrying the sensor according to the invention;
• Figure 9 is a cross-sectional view of this adapter body, taken along the line IX-IX of Figure 8;
• Figure 10 is, exploded, a partial view in axial section, illustrating, on the scale of Figures 8 and 9, the implementation of this adapter body;
• Figure 11 is a view similar to that of Figure 5, for an alternative embodiment;
• Figure 12 is a view which, similar to that of Figure 10, illustrates the mode of operation of this alternative embodiment;
• Figure 13 is a view which, similar to that of Figure 7, relates to another type of pressure tank.

As schematically illustrated in Figures 1, 6, and 13, the invention relates to a pressure tank 10 of the kind comprising, in an envelope 11, made in practice of rigid material, a separator 12 which divides the internal volume of said envelope 11 into two chambers of variable volume, namely a liquid chamber 13 and a gas chamber 14, said casing 11 itself comprising, at a distance from each other, two orifices, not detailed in these figures, at namely a liquid orifice and a gas orifice, and said liquid chamber 13 and said gas chamber 14 each being respectively in communication with said orifices.

In the embodiment more particularly shown in Figures 1, 6, and 7, the casing 11 is generally elongated, and it thus forms, over at least a portion of its length, in practice in its middle part, a cylinder 15 of diameter D, while its ends 16, 17 each form a hemisphere respectively.

It is in the axis of the assembly that the liquid orifice and the gas orifice are present, the first in the center of the end 16, that generally disposed towards the bottom when the pressure tank 10 is used vertically, FIGS. 1 and 6, and the second at the center of the end 17, that generally disposed upwards for such an orientation of the pressure tank 10.

Jointly, in the embodiment illustrated in Figures 1, 6, and 7, the separator 12 is a bladder, and in practice a bladder of flexible material, which is also elongated, like the envelope 11 , and whose opening, commonly called mouth, surrounds the gas orifice of the latter.

The bottom, blind, of this bladder forms, at the other end of it, what is agreed here to be called a transverse wall 18, this transverse wall 18, which is in fact generally in the shape of a hemisphere , extending generally transversely to the envelope 11.

Distant from both of the liquid and gas orifices of the casing 11, the transverse wall 18 of the separator 12 is generally movably mounted in this casing 11, due to the movements of contraction or expansion what is likely to be known therein the bladder constituting in this case this separator 12.

These provisions are well known in themselves, and not being in themselves part of the present invention, they will not be described in more detail here.

In a manner also known per se, a sensor 20 is used in the pressure tank 10 thus formed, which is a sensor sensitive to the presence of liquid, and which, thanks to an orifice of the envelope 11 in communication with the gas chamber 14, extends in said gas chamber 14.

In practice, this sensor 20 is carried by a tubular plug 21 controlling the orifice of the envelope 11 through which it extends.

In the embodiment shown, and according to methods described in more detail later, this orifice is, very simply, the gas orifice of the envelope 11.

In addition, the tubular plug 21 is, in the embodiment shown, a threaded plug with a conical thread, which thereby ensures all the desired tightness.

According to the invention, for the rest configuration, at least, when empty, of the transverse wall 18 of the separator 12, the sensitive end 22 of the sensor 20, which forms, in practice, the free end, is closer of said transverse wall 18 than of the orifice of the casing 11 through which it extends into the gas chamber 14, or, in other words, of the tubular plug 21 controlling this orifice.

In addition, the sensor 20 is preferably, according to the invention, an optical probe.

Such an optical probe is well known in itself.

It is for example described in the French patent which, filed on March 25, 1971 under No 71.11420, was published under No 2.130.037.

It will therefore not be described in full detail here.

It will suffice to indicate that it comprises an optical conduit 23, which forms its essential constituent, and which is itself formed of at least one optical fiber.

The end of this optical conduit 23 internal to the envelope 11 forms the sensitive end 22.

In the embodiment shown, this sensitive end 22 is slightly tapered, before ending with a rounded end.

But it can have a completely different configuration, and for example one or the other of those described in the patent No. 71 11420 mentioned above.

The other end of the optical conduit 23 is intended to be in connection with a signal processing device 25, as shown diagrammatically in FIG. 6.

The corresponding link 26 can be provided by the optical conduit 23 itself, the latter duly extending out of the envelope 11 for this purpose.

Alternatively, this connection 26 can be provided by an electrical conductor.

In this case, and as shown diagrammatically in broken lines in FIG. 2, it can be attached to the tubular plug 21, a plate 27 on which is in turn attached a connector 28 suitable for ensuring the necessary conversion between the signal optical and the electrical signal, or in other words, to serve as an interface between the optical conduit 23 and an electrical conductor.

It should be noted, however, that a direct connection, via its optical conduit 23, of the sensor 20 with the signal processing device 25, has the advantage of being much more reliable and of being insensitive to interference, which can make it necessary in the case where the pressure tank 10 concerned is located in an environment which is not compatible with such a signal processing device 25, and, for example, in a humid, aggressive and / or explosive environment, this processing device of signals 25 then advantageously being in a room remote from that in which the pressure tank 10 is itself located.

Of course, the connection 26 can equally be provided by an optical conduit separate from the optical conduit 23 of the probe forming the sensor 20, and, in this case, the connector 28 is simply a connector suitable for ensuring a connection between two conduits optical.

In practice, the optical conduit 23 has a very reduced diameter, less often than 1 mm, or even 0.5 mm.

Its constituent material also has a relative capacity for elastic deformation.

Given this relative capacity for elastic deformation of its optical conduit 23 and the slender character, with a reduced transverse dimension thereof, the optical probe forming according to the invention the sensor 20 is capable, by simple gravity, of taking the arrow.

In the embodiment shown in Figures 1, 6 and 7, this optical probe is reduced in practice to a section of optical conduit 23, which, apart from such a possible deflection, is substantially rectilinear.

In practice, the length L of this section of optical conduit 23, and therefore of the optical probe forming the sensor 20, counted from the tubular plug 21 carrying the latter, is preferably greater than 1.5 times the diameter D of the cylinder. 15 which the envelope 11 of the pressure tank 10 forms in its middle part.

In the embodiment illustrated in FIGS. 1 and 6, according to which the pressure tank 10 is arranged vertically, with its gas orifice upwards, the optical probe forming the sensor 20 remains substantially rectilinear, suspended from it is, in a way, to the tubular plug 21 from which it extends.

However, in the embodiment illustrated in FIG. 7, according to which the pressure tank is arranged horizontally, this optical probe, which then extends in a cantilever fashion in the gas chamber 14, effectively takes , by gravity, of the arrow.

Preferably, and as shown, over at least a portion of its length from the tubular plug 21, the optical conduit 23 of the optical probe forming the sensor 20 is surrounded by a tubular guide 30 which itself extends in overhang from said tubular plug 21.

This tubular guide 30, which is in fact formed by a capillary tube, can for example be made of metal.

In this case, implanted as a seal in a bore 31, in practice an axial bore, of the tubular plug 21, it is subject to the latter by welding or brazing.

However, preferably, in order to impart progressive flexibility, upon its entry into the gas chamber 14, to the optical probe forming the sensor 20, it can advantageously be itself made of flexible material, and for example of elastomer.

In this case, it is secured by bonding to the tubular plug 21.

In all cases, the optical conduit 23 is itself preferably secured by gluing to the tubular guide 30 which thus accompanies it over a portion of its length.

This bonding can for example be carried out in the following manner: in the tubular plug 21, there is provided, transversely, a bore 32, which intersects the bore 31, by dividing the tubular guide 30 into two distinct sections 30A, 30B, and which is used for the injection, under pressure, of glue into the gap between the optical conduit 23 and both of said sections 30A, 30B of the tubular guide 30, this transverse bore 32 then being closed by a plug 33.

Anyway, the passage of the tubular plug 21 by the catper 20 is made tight.

Anyway, also, the tubular guide 30 preferably has, and as shown, at its free end, at the internal periphery of its outlet, a chamfer 35, which, cutting down its corresponding edge obliquely, allows to spare the optical conduit 23 during any deflections of the latter relative to this tubular guide 30.

Preferably, and as shown, the sensitive end 22 of the sensor 20 is surrounded by a tubular cage 36, being disposed radially at a distance from the side wall of the latter and axially set back relative to its outlet.

In the embodiment illustrated in Figures 2 and 3, this tubular cage 36 is a rigid and fixed cage.

It is for example produced using a section of metal tube whose end opposite to its outlet is suitably crimped on the optical conduit 23.

The side wall of this tubular cage 36 has a sufficient diameter for a meniscus of liquid to be able to be established between it and the sensitive end 22 of the optical conduit 23.

It must therefore have a diameter greater than that of such a meniscus.

In practice, it suffices to be satisfied with a diameter of the order of 3 mm to be suitable for all types of liquid.

But of course this numerical value is given here only by way of example, and it should in no way be considered as limiting the invention.

Preferably, and as shown, to facilitate wetting of the sensitive end 22 of the optical conduit 23, the tubular cage 36 has, axially, at least one slot 37 from its outlet.

For example, two such slots 37 can be provided, being arranged in diametrically opposite positions relative to each other.

Preferably, and as shown, over at least part of its length, the optical conduit 23 of the optical probe forming according to the invention the sensor 20 is, for its protection, as well as for a reduction in its deformation capacity elastic, jacketed by a sheath 39.

Preferably, this sheath 39 extends at least from the tubular guide 30, and at least as far as the tubular cage 36.

In the embodiment shown, it extends without discontinuity from this tubular guide 30, which it partially covers, to this tubular cage 36, which it also partially covers.

In practice, this is a sheath made of synthetic material, and, for example, an elastomer sheath.

But, preferably, it is made of retractable material, and for example of heat-shrinkable material, which facilitates the positioning thereof, while allowing it to best fit the parts, tubular guide 30, optical conduit 23, and tubular cage 36, which it encloses.

If, as shown diagrammatically in FIG. 6, there occurs, at least locally, a rupture of the bladder constituting the separator 12, and if the quantity of liquid penetrating then in it is sufficient for the sensitive end 22 of the sensor 20 to be immersed therein, the signal emitted by this sensor 20 changes state, and the signal processing device 25 detects this change of state.

Of course, and as schematically represented by lines in FIG. 6, several pressure tanks 10 can be connected to the same signal processing device 25, which, on receipt of a signal indicative of a fault for one from them, makes it possible to identify which of these pressure tanks 10 is thus in default.

It follows from the above which, according to the invention, when, as shown in FIG. 6, the pressure tank 10 is arranged vertically, with its gas orifice upwards, the sensitive end 22 of the sensor 20 is advantageously located in the lower part of the gas chamber 14, which allows almost immediate detection of a possible invasion of the latter by liquid.

It is the same when, according to the implementation variant illustrated in FIG. 7, the pressure tank 10 is arranged horizontally.

In fact, due to the deflection that the sensor 20 then takes, by simple gravity, it follows that, as before, its sensitive end 22 is still at the bottom for the gas chamber 14.

Preferably, the optical probe forming the sensor 20 is put in place on the pressure tank 10 to be fitted, according to the invention, by means of an adapter body 40 shown in isolation in FIGS. 8 and 9.

At the ends, each respectively, of an axial channel 41, this adapter body 40 has, on the one hand, projecting, at its lower part, a tubular plug 21ʹ, by which, as described in more detail below, it is adapted to be attached to the pressure tank 10 to be fitted, and, on the other hand, in the hollow, at its upper part, a tapped hole 42, by which it is adapted to receive the tubular plug 21 carrying the sensor 20 to be put in place.

In the embodiment shown, this tapped hole 42 is therefore conical, like the tubular plug 21.

On the other hand, the tubular plug 21ʹ, which, like the tubular plug 21, is threaded, is cylindrical.

Anyway, the diameter of the axial channel 41 is made sufficient to allow the passage of the optical probe forming the sensor 20.

It is therefore greater than its largest diameter, measured, in practice, at its cage 36.

Jointly, the adapter body 40 has a transverse channel 43, which is in communication with its axial channel 41, and by which, as will appear below, it is adapted to receive a valve, not shown, this transverse channel forming , for this purpose, at its free end, a tapped hole 44.

In practice, the tubular plug 21ʹ is complementary to this threaded bore 44.

In practice, also, the adapter body 40 has, transversely, in the embodiment shown, three channels, all of which are in communication with its axial channel 41, and which all form a threaded bore at their free end, namely, in addition the transverse channel 43 above, which is intended to allow the introduction of gas into the gas chamber 14 of the pressure tank 10 concerned, a transverse channel 45, which is intended for example to allow the implantation of a pressure sensor , not shown, and a transverse channel 46, which is intended for example to allow the installation of a temperature sensor, also not shown, these pressure and temperature sensors being intended to allow to have additional information on the proper functioning of such a pressure tank 10.

Finally, in the embodiment shown, the adapter body 40 according to the invention is presented, at the in the form of a nut, in the form of a cylindrical block of polygonal cross section, and in practice hexagonal, which facilitates the control in rotation proper to allow the screwing or unscrewing, and which therefore facilitates the setting in place on the pressure tank 10 to be fitted.

The implementation of such an adapter body is illustrated by FIG. 10, on which the casing 11 of such a pressure tank 10 is partially represented, with its gas orifice 48, and the bladder forming the separator 12 qu 'it contains.

As illustrated, a valve body 50 is installed in the gas orifice 48, and this valve body 50, which, inside the envelope 11, is surrounded by the opening 51 of the bladder forming the separator 12 ensures the sealing of this bladder in this envelope 11, while itself being secured by a nut 52 to this envelope 11 outside of the latter.

These arrangements are well known in themselves, and, not being in themselves part of the present invention, they will not be described in more detail here.

In a manner also known per se, the valve body 50 has axially a channel 54, and, at the end thereof, on the side external to the casing 11, a threaded bore 55 suitable for the implantation of a valve ( not shown), for controlling the inflation of the bladder forming the separator 12.

According to the invention, the tubular plug 21ʹ of the adapter body 40 has the dimensions of the tapped hole 55, which are usually standard, and it is thus adapted to replace the valve normally implanted in this tapped hole 55, the latter then finding in return its place in its own tapped hole 44.

To this end, it has the same dimensions as the tapped hole 55 and therefore that the tubular plug 21ʹ, at least in diameter.

Thus the sensor 20 implemented according to the invention can advantageously, if desired, equip a pre-existing pressure tank 10.

Preferably, and as shown, there is provided, on the lower face of the adapter body 40, in a groove 56, a seal 57, for sealing cooperation with the corresponding upper face of the valve body 50.

In practice, the overhang in the gas chamber 14 of the sensor 20 therefore extends only from this valve body 50, even if, theoretically, it extends from the plug. tubular 21 carrying this sensor 20.

In the variant embodiment shown in FIGS. 11 and 12, the tubular cage 36 is formed of arms 58 mounted to move between a retracted position, FIG. 11, for which they extend substantially parallel to the sensitive end 22 of the sensor 20, around it, and a deployed position, FIG. 12, for which their free end is spaced from this sensitive end 22, and the cage 36 thus formed of such movable arms 58 is surrounded by a tube 59 which, mounted axially movable, from outside the pressure tank 10 concerned, is capable of holding said arms 58 in the deployed position when it is itself in the advanced position, FIG. 11, and in releasing them, when it is in the retracted position, figure 12.

It is, of course, for the retracted position of the movable arms 58 that the sensor 20 is placed in the pressure tank 10, which facilitates this positioning, and it is only after this that, by retraction of the tube 59, these movable arms 58 are allowed to pass into the depolated position, said positioning being first of all only partial to leave outside a sufficient grip of the tube to effectively allow its operation.

The distance separating the sensitive end 22 of the sensor 20 from the free end of the arms 58 once they have thus been deployed is then greater, which is particularly suitable in the case where the liquid present in the liquid chamber 13 is relatively viscous, because he it is then relatively easier for this liquid to reach this sensitive end 22.

As illustrated in FIG. 12, the separator 12 can usually consist of a piston mounted movable transversely in the case 11.

This piston forms alo by itself the transverse wall 18 of such a separator 12, this separator 12 reducing in this case to this transverse wall 18.

The optical probe used for constituting the sensor 20 then forms at least one helical turn 60, and, in the vicinity of its sensitive end 22, it is preferably coupled, by fixing means 61, to the piston then forming the wall transverse 18.

In the embodiment shown, this optical probe in practice comprises several helical turns 60.

Preferably, the fastening means 61 by which it is coupled to the piston forming the transverse wall 18 are rotary means, to take account of any rotation, around the axis of the assembly, of this piston in the envelope 11.

For the rest, the provisions are of the type described above.

In the foregoing, it has been assumed that the optical probe forming the sensor 20 according to the invention is implanted in advance in the pressure tank 10 concerned and that it is intended to remain permanently therein.

However, it goes without saying that it would not go beyond the scope of the present invention to have such an optical probe in such a pressure tank only during a check of the latter.

The present invention is moreover not limited to the embodiments and implementation described and shown, but encompasses any variant.

In particular, the sheath lining the optical fiber of the optical probe preferably used as sensor can, if desired, be molded onto the assembly, rather than being made of retractable material.

Furthermore, although for the reasons explained, the sensor used is preferably an optical probe, it would not go beyond the scope of the invention either to replace it with another type of sensor.

In addition, the orifice of the envelope of the pressure tank through which this sensor extends into the gas chamber thereof is not necessarily the gas orifice of this envelope.

It may also be a particular orifice of this envelope, the only one intervening for its control is a tubular plug carrying the sensor.

In this case, the sensor overhang in the gas chamber is made from this tubular plug.

Finally, the envelope of the pressure tanks likely to be concerned is not necessarily cylindrical or elongated.

It can also be a spherical envelope.

Claims (26)

1. A pressure tank of the type comprising, in an envelope (11) comprising at a distance from each other two orifices, namely a liquid orifice and a gas orifice, on the one hand, a separator (12) which divides said envelope into two chambers of variable volume, namely a liquid chamber (13) and a gas chamber (14), with which each of said orifices is respectively in communication, and which, at least transversely with respect to said casing (11), has a wall (18), here called for simple convenience, transverse wall distant from both of the said orifices, and movably mounted in said casing (11), and, on the other on the other hand, a sensor sensitive to the presence of liquid (20), which, thanks to an orifice in the envelope (11) in communication with the gas chamber (14), extends into said gas chamber ( 14), characterized in that, at least for the idle configuration, when empty, of the transverse wall (18) of the separator (12), the sensitive end (2) of said sensor (20) is closer to said transverse wall than to the orifice of the envelope (11) through which it extends into the gas chamber (14). 2. Pressure tank according to claim 1, characterized in that the sensor (20) is an optical probe comprising an optical conduit (23), the internal end of the envelope (11) forming the sensitive end ( 22), and the other end of which is intended to be in connection with a signal processing device (25), said optical conduit (23) itself being formed from at least one optical fiber. 3. Pressure tank according to claim 2, characterized in that the optical probe forming the sensor (20) is carried by a tubular plug (21). 4. Pressure tank according to claim 3, characterized in that, over at least a portion of its length from the tubular plug (21), the conduit optical (23) of the optical probe forming the sensor (20) is surrounded by a tubular guide (30) which extends in overhang from said tubular plug (21). 5. Pressure tank according to claim 4, characterized in that, at its free end, the tubular guide (30) has, at the internal periphery of its outlet, a chamfer (35). 6. Pressure tank according to claim 4, characterized in that the tubular guide (30) is made of flexible material. 7. Pressure tank according to any one of claims 2 to 6, characterized in that the optical conduit (23) of the optical probe forming the sensor (20) is made of relatively flexible material. 8. Pressure tank according to claim 7, characterized in that, the separator (12) being a bladder of flexible material whose bottom forms the transverse wall (18), the optical probe forming the sensor (20) is reduced to a section of optical conduit, which, apart from the arrow of which it may be the object, is substantially rectilinear. 9. A pressure tank according to claims 3 and 8, taken together, characterized in that, its envelope being elongated and forming, over at least a portion of its length, a cylinder (15), the length (L) of said section of optical conduit from the tubular plug (21) is greater than 1.5 times the diameter (D) of said cylinder (15). 10. Pressure tank according to any one of claims 2 to 9, characterized in that the optical probe forming the sensor (20) extends overhanging in the gas chamber (14). 11. Pressure tank according to claim 7, characterized in that, the separator (12) being a piston which forms the transverse wall (18) and therefore reducing to this transverse wall, the optical probe forming the sensor (20) forms at least one helical turn (60), and, near its sensitive end (22), it is coupled to said piston. 12. Pressure tank according to any one of claims 2 to 11, characterized in that, over at least part of its length, the optical conduit (23) of the optical probe forming the sensor (20) is jacketed by a sheath (39). 13. Pressure tank according to claim 12, characterized in that said sheath (39) is of shrinkable material. 14. Pressure tank according to claims 4 and 12, taken together, characterized in that said sheath (39) extends at least from said tubular guide (30). 15. Pressure tank according to any one of claims 1 to 14, characterized in that the sensitive end (22) of the sensor (20) is surrounded by a tubular cage (36), being disposed radially away from the side wall thereof and axially set back relative to its outlet. 16. Pressure tank according to claim 15, characterized in that said tubular cage (36) is rigid and fixed. 17. Pressure tank according to claim 16, characterized in that the side wall of said tubular cage (36) has axially at least one slot (37) from its outlet. 18. Pressure tank according to claim 15, characterized in that said tubular cage (36) is formed of arms (58) movable between a retracted position, for which they extend substantially parallel to the sensitive end (22) of the sensor (20) around it, and a deployed position, for which their free end is spaced therefrom, and it is surrounded by a tube (59), which, mounted axially movable, is capable of maintaining said arm (58) in the deployed position when it is itself in the advanced position, and release when in the back position. 19. Pressure tank according to claims 12 and 15, taken together, characterized in that said sheath (39) extends at least as far as said tubular cage (36). 20. Pressure tank according to any one of claims 1 to 19, characterized in that the sensor (20) is fixed to its casing (11) by means of an adapter body (40) having, at the ends, each respectively of an axial channel (41), on the one hand, projecting, a tubular plug (21ʹ), by which it is adapted to be attached to such an envelope (11), and, on the other hand, in hollow, a bore (42), by which it is adapted to receive a tubular plug (21) carrying said sensor (20). 21. Pressure tank according to claim 20, characterized in that, the separator (12) being formed by a bladder, the adapter body (40) is adapted to be attached, by its tubular plug (21ʹ), to the body of valve (50) usually fitted to the gas orifice of the casing (11) in substitution for the valve itself usually fitted to such a valve body (50), and it comprises transversely, in communication with its axial channel (41 ), a bore (44) suitable for receiving such a valve, this bore (44) having, at least in diameter, the same dimensions as its tubular plug (21). 22. Pressure tank according to claim 21, characterized in that the adapter body (40) comprises transversely at least one other channel (45, 46) suitable for the installation of another sensor. 23. Pressure tank according to any one of claims 20 to 22, characterized in that the threaded plug (21ʹ) which it comprises is threaded, and it is in the form of a block of polygonal cross section, and , for example, hexagonal. 24. Pressure tank according to any one of claims 20 to 23, characterized in that the diameter of the axial channel (41) of the adapter body (40) is at least equal to the maximum diameter of the sensor (20). 25. Pressure tank according to claim 3, characterized in that the tubular plug (21) also carries a connector (28) suitable for ensuring conversion between an optical signal and an electrical signal. 26. Pressure tank according to claim 3, characterized in that the tubular plug (21) also carries a connector (28) suitable for ensuring a connection between two optical conduits.

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