EP0631103B1 - System for cleaning tubes with sponge balls - Google Patents

Description

It is known that permanent cleaning of the internal surface of condenser or exchanger tubes heat can be achieved by continuous circulation inside these tubes a stream of water charged with elastic balls formed by a spongy material.

These sponge balls must be impregnated water before commissioning.

The purpose of this impregnation is to purge the air contained in the open cells of the structure spongy balls in order to give these balls a apparent density very close to that of water: if the air in the balls was not purged, the balls would be lighter than water and they would tend to float and clean only the upper part of the generally horizontal tubes of the condenser or the like.

The impregnation of the balls is most often done manually by kneading the balls under water before their injection into the closed cleaning circuit including the tubes to be cleaned.

This manual operation is long and tedious. It becomes difficult, even dangerous, when these are "abrasive" type balls containing particles with sharp edges.

We also proposed, for example in the document US-4 420 038, a device for impregnating sponge balls intended for cleaning the tubes of a condenser or the like, comprising an interposed reservoir between first and second associated valves respectively to a water intake pipe and to a water evacuation pipe, a fitting fitted with a third valve connecting the top of the tank to a source of new cleaning balls, a mesh grid too small to pass the balls arranged at inside the tank so as to reserve at the top of this one a room inaccessible to the balls, a pipe equipped with a fourth valve connecting said chamber to a evacuation and a device capable of generating a depression in this room, this generating device of vacuum being a vacuum pump.

This solution is difficult to implement in reason in particular for the need to provide means to separate the air and water drawn in simultaneously and the frequent presence of debris in the water surrounding the balls, debris that clog or damage some small section components of the vacuum system.

The invention relates generally to installations cleaning tubes above defined and more particularly, but not exclusively, the processes and water impregnation devices for cleaning balls used by these facilities.

It aims, above all, to make these methods and devices as they overcome the drawbacks mentioned above by proposing a solution to the efficient and robust, which lends itself to automation with a high degree of security, which allows reduce maintenance costs and care accordingly monitoring required by cleaning facilities corresponding.

To this end, the device for impregnating sponge balls intended for cleaning the tubes of a condenser or the like according to the invention comprises a reservoir interposed between a first and a second valves associated respectively with a pipe water intake and a water evacuation pipe, a fitting with a third valve connecting the top from the tank to a source of new cleaning balls, a mesh grid too small to let the balls arranged inside the tank so that reserve a room at the top of this room inaccessible to balls, a pipe fitted with a fourth valve connecting said chamber to an evacuation and a clean device to cause depression in this room, and it's essentially characterized in that the device vacuum generator consists of a cylinder piston with one of the two compartments separated by the piston communicates with the chamber in such a way that each piston goes back and forth successively generates an increase of a quantity well determined from the volume defined by the interior of the tank and through the spaces that communicate with this interior, when the above four serving valves of the tank are closed and then a cancellation of this increase.

Regarding impregnation processes implementing the above devices they are characterized according to the invention by the following steps: the first two valves being closed and the other two open, we introduce in the tank a load of new balls through the third valve; then, the second and the third valves being closed and the other two open, we admit water in the tank until full in water; then, all of the four valves being closed, the piston is actuated in the direction which corresponds to an increase in the volume in communication with the inside of the tank, which subjects this volume to a depression by emptying at least partially the balls of air they contain, air that is collected in the upper chamber of the tank and the capacity that communicates with this room; after what the first and fourth valves are opened so that refill all the volumes considered with water, which impregnates the balls at least partially with water emptied of air and the piston or the like is actuated in the direction reverse of the previous one to put it back in its position initial, the cycle of the two steps defined above which operate the piston back and forth can be renewed one or more times.

• si l'on appelle V le volume de la cylindrée du vérin et v le volume, à la pression atmosphérique, de l'air contenu dans les cellules de la charge de boules introduites dans le réservoir, on donne à V une valeur supérieure à 4v,
• le vérin est constitué par une pompe à membrane dont l'organe mobile constitue le fond du réservoir,
• la chambre haute intérieure au réservoir est traversée par un couloir vertical délimité latéralement par une grille, couloir prolongeant vers le bas le raccord du réservoir à la troisième vanne et un flotteur est disposé au-dessous de ce couloir de façon à empêcher les boules contenues dans le réservoir de remonter dans ledit couloir,
• le dispositif comprenant le réservoir, le vérin et les tuyauteries et vannes de desserte, est monté en dérivation sur la tuyauterie de recyclage des boules de nettoyage des tubes d'un condenseur ou analogue, tuyauterie qui s'étend de la sortie à l'entrée de ce condenseur,
• dans une installation selon l'alinéa précédent, le dispositif comprenant le réservoir, le vérin et les tuyauteries et vannes de desserte est associé à un compteur de boules et à un trieur de boules de façon telle que toute extraction, hors de l'installation, d'une charge de boules usées soit compensée par l'introduction dans cette installation d'une charge équivalente de boules neuves imprégnées d'eau, et le fonctionnement de l'ensemble est automatisé.

In advantageous embodiments, use is also made of one and / or the other of the following arrangements:

• if we call V the volume of the cylinder displacement and v the volume, at atmospheric pressure, of the air contained in the load cells of balls introduced into the tank, we give V a value greater than 4v ,
• the jack is constituted by a diaphragm pump whose movable member constitutes the bottom of the tank,
• the upper chamber inside the tank is crossed by a vertical corridor delimited laterally by a grid, corridor extending downwards the connection of the tank to the third valve and a float is arranged below this corridor so as to prevent the balls contained in the reservoir to rise in said corridor,
• the device comprising the reservoir, the cylinder and the serving pipes and valves, is mounted in bypass on the recycling pipe for cleaning balls for condenser tubes or the like, piping extending from the outlet to the inlet of this condenser,
• in an installation according to the preceding paragraph, the device comprising the reservoir, the cylinder and the serving pipes and valves is associated with a ball counter and a ball sorter so that any extraction from the installation, of a load of used balls is compensated by the introduction into this installation of an equivalent load of new balls impregnated with water, and the operation of the assembly is automated.

The invention includes, apart from these arrangements main, certain other provisions which preferably used at the same time and which will be more explicitly question below.

In the following, we will describe some modes preferred embodiments of the invention with reference to attached drawings of course in a nonlimiting manner.

Figures 1 to 3 of these drawings show schematically a device, established in accordance with the invention, allowing water balls to be impregnated cleaning, this device being mounted in respectively three different operating phases.

Figure 4 schematically shows an installation cleaning balls equipped with such a device.

Figure 5 shows schematically, on the one hand, a preferred construction method proposed in accordance with the invention for the impregnation device and, on the other share, the preferred association of this device with other accessories known per se.

The balls 1 to be impregnated with water are balls spongy rubber with open porosity.

The device shown in Figures 1 to 3 includes a tank 2 served near its base by a water inlet pipe 3 fitted with a first valve 4 and, near its top, by a pipe water outlet 5 fitted with a second valve 6.

The top of the tank 2 is connected, through a third valve 7, to a hopper 8 for receiving balls 1 new.

The upper portion of tank 2 is crossed by a horizontal grid 9 which delimits above it an enclosure 10.

This enclosure is itself crossed by a vertical corridor delimited laterally by a grid cylindrical 11 connecting the hopper connection 8, fitted with valve 7 with the inside of the tank 2.

The meshes of the mesh elements 9 and 11 are small enough that they cannot be crossed by balls 1 and large enough so that none only negligible pressure drop is suffered by water as it passes through these meshes.

A float 12, constituted for example by a hollow ball filled with air, is arranged, in a structure light guide 13 constituted in particular by metal rods, just below the mouth bottom of the screened corridor 11 so that free this mouthpiece for its normal rest position illustrated in Figure 1 and instead close this mouthpiece for its high position shown on the Figures 2 and 3.

This sealing prevents any rise of balls in lane 11 during the impregnation process in water, balls whose impregnation with water could then be compromised.

Enclosure 10 is atmospheric or more precisely to an evacuation pipe, by a pipe 14 fitted with a fourth valve 15.

A jack 17 comprising here a cylinder 18 and a piston 19 with rod 20 is put in communication with the tank 2 as follows: one A of the two chambers A and B, of cylinder 18, separated by the piston 19, is directly connected to the portion of the pipeline 14 which is located between the tank 2 and the valve 15.

The portion, of line 14, which is in downstream of valve 15 is here directly connected to the discharge pipe 5, which opens out below above a receiving basket 21.

• une conduite de purge 22 raccordée à la base du réservoir 2 et équipée d'une vanne 23,
• entre la vanne 7 et la base de la trémie 8, deux mécanismes à tiroir 24 et 25 propres à délimiter entre eux, lorsqu'ils se trouvent en position de fermeture, un espace 26 de volume bien déterminé, ce qui peut servir au dosage précis des charges de boules introduites dans le réservoir 2,
• une poignée 27 terminant la tige de piston 20 du vérin 17 et permettant les manoeuvres de cette tige à la main.

We still see in Figure 1:

• a purge line 22 connected to the base of the tank 2 and equipped with a valve 23,
• between the valve 7 and the base of the hopper 8, two slide mechanisms 24 and 25 capable of delimiting between them, when they are in the closed position, a space 26 of well determined volume, which can be used for precise dosing loads of balls introduced into the tank 2,
• a handle 27 terminating the piston rod 20 of the jack 17 and allowing the maneuvers of this rod by hand.

The operation of the device thus described is the following.

Initially, tank 2 is empty in this sense that it contains neither water nor ball, and the valves 4, 6 and 23 are closed.

Then introduced into the tank 2, through valve 7 open and lane 11, the ball load 1 to impregnate with water.

The higher level of the ball load as well introduced must not exceed, inside the tank 2, that of the base of the float 12.

We then close valve 7 and open both valves 4 and 15.

The water is then introduced into the reservoir 12 and the level of this water rises in said reservoir, of which the air content escapes through line 14, the valve 15 open and line 5.

When the water level rises in the tank, float 12 rises gradually at the same time as the balls and closes the base of the corridor 11.

When the entire interior volume at tank 2, including that of the upper enclosure 10 as well as that of line 14 up to the level of the valve 15, is filled with water, as can be seen on the Figure 2, we close the two valves 4 and 15, which delimits a totally closed capacity filled with water in which are embedded balls 1 still loaded of air.

We then pull on the handle 27 so as to create in the capacity defined above a certain depression, which evacuates part of the air contained in the balls, as shown in Figure 3.

This air rises to the top of the tank 2 and collects in enclosure 10 and in the corridor 11, enclosure and corridor in which the balls are not not allowed.

After enough time has passed for ensure this evacuation of the air contained in the balls towards enclosure 10, valve 4 is opened, which admits a new volume of water inside tank 2, volume which permeates the balls 1 at least partially emptied of their initial air.

At the same time as this opening of the valve 4 or shortly after, the valve 15 is opened to expel the air from the circuit and make possible a full refill water capacities.

Then, using the handle 27, we push the piston 19 to its initial position, the excess water being discharged through the valve 15.

At the end of this cycle, the impregnation of the balls in water is incomplete if the cylinder capacity, i.e. the volume of air or water displaceable in chamber A when of each complete back-and-forth movement of the piston 19, is insufficient, relative to the volume of water with which one wishes to impregnate balls.

We then complete the impregnation of these balls in performing a second cycle of operations identical to first after closing the two valves 4 and 15.

If the volume of water that you want to introduce into the balls is important compared to the displacement of the cylinder 17, the impregnation of these balls may require more than two successive cycles.

The number of cycles required can be determined as follows.

If v is the volume at atmospheric pressure of the air contained in the cells of the charge of balls to be impregnated and if V is the displacement of the jack 17, the pressure P, expressed in absolute bars, which prevails in the tank 2 after the recoil of the piston 19 corresponding to FIG. 3 is given by the formula P (V + v) = 1.v

In practice, we see that the pressure P is less than 0.2 bar so that the balls are sufficiently impregnated, that is to say that their apparent density is sufficiently close to that of the water.

We deduce that the complete impregnation of balls can be performed during a single cycle of operations if the load of the admitted balls is such that the pressure P after the first "retreat" of the piston is less than 0.2 bar, i.e. if the volume V is greater than 4v.

Otherwise, at least a second cycle of operations must be carried out during which the pressure P 'obtained in the reservoir after the piston 19 recedes again to its position illustrated in FIG. 3 is given by the formula P '(V + v') = 1.v ' formula in which v 'is the volume, at atmospheric pressure, of the air remaining in the cells of the charge of balls at the end of the last cycle carried out.

As the quantity v 'can be calculated by the formula (v-v ') (v + V) = vV

we can deduce from formula (2) above the value of P 'as a function of V and v.

If this value is still greater than 0.2 bar, there must be a third cycle and so on.

It appears from the above that the balls introduced into tank 2 are not properly impregnated with water only if the volume of air they initially contain is less than or equal to the volume maximum calculated acceptable according to the displacement V of the cylinder and the number of cycles provided for it.

In order not to risk exceeding this threshold, it is recommended to precisely dose each load of balls new introduced into the tank for their impregnation: this is the role assigned to drawers 24 and 25 defining the airlock 26 of well defined volume, as well as described above.

Of course, agitating means can be provided in or on hopper 8 to ensure that the balls descend by simple gravity into the airlock 26 upon opening the upper drawer 24, which opening can be controlled by closing the lower drawer 25.

When the charge of balls 1 introduced into the tank 2 is sufficiently impregnated with water, this charge is evacuated by a stream of water through valve 6 open and line 5 and it is collected in the basket 21.

Figure 5 shows in its right part another construction of the above impregnating device described.

In this other construction, the elements identical or analogous to those previously described are assigned the same references as above.

• ici, le vérin est constitué par une pompe à membrane 28 et la membrane déformable 29 de cette pompe constitue elle-même le fond du réservoir 2,
• une chambre 30 disposée au-dessous de cette membrane 29 est mise à l'air libre en 31,
• la membrane 29 est reliée par une tige 32 qui traverse de manière étanche le fond de la chambre 30 à une seconde membrane souple 33 identique qui divise un boítier 34 inférieur en deux compartiments C et D susceptibles d'être reliés isolément et alternativement à une source d'air comprimé et à l'atmosphère, respectivement à travers deux raccords 35 et 36.

The main differences between said other construction and the previous one are as follows:

• here, the jack is constituted by a membrane pump 28 and the deformable membrane 29 of this pump itself constitutes the bottom of the tank 2,
• a chamber 30 arranged below this membrane 29 is vented to the open air at 31,
• the membrane 29 is connected by a rod 32 which sealingly crosses the bottom of the chamber 30 to a second identical flexible membrane 33 which divides a lower housing 34 into two compartments C and D capable of being connected in isolation and alternately to a source compressed air and to the atmosphere, respectively through two connections 35 and 36.

The structure 13 for supporting and guiding the float 12 is here supported by a grid 16 which crosses the interior of tank 2 a little above the membrane 29.

This grid 16, like grid 9, is arranged so that it cannot be crossed by the balls.

Finally, there is no comparable capacity here to compartment A of cylinder 17 above on the section of line 14 between chamber 10 and line evacuation 5.

The operation of this embodiment is exactly the same as the previous one, the commands the handle 27 manual being here replaced by the vertical displacements of the membrane 29, themselves controlled by alternative communication of each two compartments C and D with an air source tablet, each of these ports one of two compartments being synchronized with a setting communication of the other compartment with the atmosphere outside.

As indicated above, it is particularly advantageous, according to the invention, to mount the assembly impregnation of balls described above on the piping 37 for recycling balls fitted to an installation cleaning the tubes 38 constituting a condenser or heat exchanger, as seen in Figure 4.

The tubes 38 in question, which form a bundle horizontal, are supplied with cold water from a line 39 and the heated water coming out of these tubes is evacuated through a pipe 40.

This pipe 40 is equipped with a device to grids 41 for collecting the cleaning balls and the recycling piping 37 is itself fitted with a circulation pump 42, an airlock 43 used to collect the balls when we want to stop their circulation, then, at its downstream end, an injection nozzle 44 of the balls opening into the intake pipe 39.

We find in this figure 4 the valve 4 above allowing water to enter the device impregnator as well as the outlet pipe 5 of this device and that its loading hopper 8 associated with the corresponding valve 7.

In this case, the impregnated balls emerging from the tank through line 5 are directly injected into recycling tubing 37 instead of collected in basket 21.

According to preferred embodiments, the impregnating device above is further associated with a sorter of balls of the type which is the subject of document US-A-4 974 662 as well as a ball counter like those currently known.

The assembly thus formed ensures a fully automatic operation of the cleaning considered.

We remind here that the continuous cleaning of tubes 38 is only effective if the diameter of the balls is greater than the inside diameter of the tubes to clean and if the number of balls in circulation is sufficient for the time separating on average two consecutive ball passes in the same tube is not not too high.

The sorter covered by the above patent allows permanently remove used balls from the circuit, the diameter has become too small.

As for the ball counter, it measures continuously the number of balls remaining in circulation: when this number of balls becomes insufficient for ensure effective cleaning, i.e. when the number of missing balls reaches a preset threshold, said counter emits a signal indicating that a charge of new balls must be reinjected into the circuit cleaning.

The impregnation device described above is sized according to the desired importance for this load of new balls and it allows to reinject this load in the circuit as soon as the counter gives it the signal.

The whole considered is represented on the figure 5.

The ball counter mounted on the recycling 37 is designated by reference 45.

Sorter 46 is mounted on the same pipe just downstream of counter 45.

Worn balls whose diameter has become too large small are diverted by a line 47 towards a collector of worn balls 48 whose base, in the shape of a truncated cone or the like, communicates with a valve 49 for draining worn balls.

The manifold 48 is connected to the pipe water inlet 3 above, fitted with valve 4.

A grid 50 mounted in this collector prevents that the used balls can have access to this line 3.

A gate valve 51 mounted on said pipe 3 makes it possible to fine-tune the selection made by sorter 46.

Indeed, by adjusting using this valve 51 the flow of water that flows through all of the two lines 47 and 3, adjust the degree of suction exerted through the sorter on the worn balls: more this suction effect is powerful and the higher the value of threshold which must be reached by decreasing by the diameter of worn balls to justify their replacement by new balls is high.

It should be noted that, in this embodiment of Figure 5, we no longer find the drain valve 23 previous, the emptying of the tank 2 can be here carried out through the valve 4, the manifold 48 and the valve 49.

The functioning of this set, which highlights mainly works of openings and closings of valves and drawers and that can therefore be very easily is the following.

• fermeture des vannes 52, 6 et 15 et ouverture des vannes 49 et 7, ce qui évacue les boules usées recueillies dans le collecteur 48, à travers la vanne 49, en même temps que l'eau qui était contenue dans ledit collecteur 48 et dans le réservoir 2,
• fermeture du tiroir supérieur 24 et ouverture du tiroir inférieur 25, ce qui déverse dans le réservoir 2 la charge de boules contenues dans le sas 26, puis fermeture des vannes 7, 49 et du tiroir inférieur 25,
• ouverture des vannes 52 et 15 pour laisser le collecteur 48 et le réservoir 2 se remplir d'eau,
• fermeture des vannes 4 et 15, puis injection d'air comprimé dans la chambre C pour faire descendre la membrane 29 afin de créer un vide dans le réservoir 2 et d'extraire l'air des boules,
• ouverture de la vanne 4 pour admettre l'eau dans le réservoir 2 et imprégner ainsi d'eau les boules, puis ouverture de la vanne 15 pour évacuer l'air accumulé dans l'enceinte 10,
• injection d'air comprimé dans la chambre D et mise à l'air libre de la chambre C pour ramener la membrane 29 en sa position haute,
• répétition éventuelle au moins une fois du cycle d'imprégnation mettant en oeuvre le va-et-vient de la membrane 29,
• ouverture de la vanne 6 pour injecter les boules ainsi imprégnées d'eau dans le circuit 37,
• ouverture du tiroir supérieur 24 et actionnement de l'agitateur des boules contenues dans la trémie 8 pour remplir à nouveau de boules le sas 26.

When the ball counter 45 indicates that the number of balls in circulation is insufficient to ensure effective cleaning of the tubes 38, that is to say when the number of missing balls reaches the alarm threshold, it triggers the cycle d successive operations below:

• closing of the valves 52, 6 and 15 and opening of the valves 49 and 7, which evacuates the used balls collected in the collector 48, through the valve 49, at the same time as the water which was contained in said collector 48 and in the tank 2,
• closing of the upper drawer 24 and opening of the lower drawer 25, which pours into the tank 2 the load of balls contained in the airlock 26, then closure of the valves 7, 49 and of the lower drawer 25,
• opening of the valves 52 and 15 to let the manifold 48 and the tank 2 fill with water,
• closing of the valves 4 and 15, then injection of compressed air into the chamber C to bring the membrane 29 down in order to create a vacuum in the tank 2 and extract the air from the balls,
• opening of the valve 4 to admit water into the tank 2 and thus impregnate the balls with water, then opening of the valve 15 to evacuate the air accumulated in the enclosure 10,
• injection of compressed air into chamber D and venting of chamber C to bring the membrane 29 back to its high position,
• possible repetition at least once of the impregnation cycle implementing the back and forth of the membrane 29,
• opening of the valve 6 to inject the balls thus impregnated with water into the circuit 37,
• opening of the upper drawer 24 and actuation of the agitator of the balls contained in the hopper 8 to refill the airlock 26 with balls.

The assembly is then ready to accomplish again following the above operations which automatically allow to evacuate a given load of used balls and to introduce an equivalent load of new balls after impregnate them with water.

As a result of what, and whatever the mode of adopted implementation, we finally obtain a device which allows the balls of an installation to be impregnated with water cleaning, device whose constitution and implementation sufficiently result from the above.

This device has significant advantages by compared to those previously known and in particular the following.

It is extremely rustic and robust, mesh of the grids which it comprises having dimensions relatively large, which removes the risk clogging or deterioration of these grids by different debris likely to be in the water training balls.

It lends itself to very advanced automation, particularly when combined with the counting and sorting subject of the embodiment described with reference to FIG. 5, which makes it possible to significantly reduce monitoring costs of the cleaning system as a whole.

Indeed, the only intervention required by the entire condenser cleaning system or the like is then limited in everything and for everything to filling the hopper 8 with new balls when this hopper no longer contains a sufficient number of balls.

The capacity of this hopper can be significant, filling it into balls does not require only two or three interventions per year, which represents a significant labor saving by compared to current installations for which impregnation of the balls to be injected must be carried out manually several times a month.

In addition, the possible automation of the whole of the installation allows the cleaning of the condenser or the like a high degree of safety since, with this installation, we are sure that the balls in circulation ensuring cleaning are at all times, on the one hand, in sufficient number, and on the other hand, in a low wear condition for which cleaning efficiency is high.

As it goes without saying, and as it results from elsewhere already from the above, the invention is in no way limited to those of its modes of application and embodiment which have been more specifically considered.

Claims (7)

1. Apparatus for impregnating spongy balls for cleaning the tubes of a condenser or the like, the apparatus comprising a tank (2) interposed between first and second (4, 6) valves associated respectively with a water inlet duct (3) and with a water outlet duct (5), a cqupling provided with a third valve (7) connecting the top of the tank to a source (8) of new cleaning balls (1), a grid (9) having a mesh that is too small to allow the balls to pass disposed inside the tank in such a manner as to define a chamber (10) at the top of the tank which is inaccessible to the balls, a duct fitted with a fourth valve (15) connecting said chamber to an outlet, and a device suitable for generating a pressure reduction in said chamber, the apparatus being characterized in that the device for generating a pressure reduction is constituted by a pump (17,28) having a piston in which one of two compartments separated by the piston
      (19, 29) communicates with the chamber (10) in such a manner that each go-and-return stroke of the piston successively increases by a well-determined quantity the volume defined by the inside of the tank and by the spaces in communication with said inside when the four above-mentioned valves serving the tank are all closed, and then cancels said increase.
2. Apparatus according to claim 1, characterized in that the pump is constituted by a diaphragm pump whose moving member (29) constitutes the bottom of the tank (2).
3. Apparatus according to claim 1 or 2, characterized in that the upper chamber (10) inside the tank (2) has, passing through it, a vertical chimney that is laterally defined by a grid (11), the chimney extending downwards the coupling between the tank and the third valve (7), and in that a float (12) is disposed beneath said chimney in such a manner to prevent the balls contained in the tank from moving back up inside said chimney.
4. A cleaning installation for cleaning tubes in a condenser or the like by means of balls, the installation being characterized in that it comprises the apparatus according to anyone of claims 1 to 3, including the tank (2), the pump (17, 28), and the associated pipework and valves serving them connected in parallel with the pipework (37) for recycling the balls, which pipework extends from the outlet of the condenser to the inlet thereof.
5. A cleaning installation according to claim 4, characterized in that the apparatus comprising the tank (2), the pump (17, 28) and the associated pipework and valves serving them is associated with a ball counter (45) and with a ball sorter (46) in such a manner that any removal of a charge of worn balls from the installation is compensated by insertion into said installation of an equivalent charge of new balls impregnated with water, and in that the operation of the assembly is automated.
6. An impregnation method implementing the apparatus according to anyone of claims 1 to 3, characterized by the following sequence of steps: with the first two valves (4, 6) closed and the other two valves (7, 15) open, a charge of new balls (1) is inserted into the tank (2) through the third valve (7); then, with the second and third valves (6, 7) closed and with the other two valves (4, 15) open, water is admitted into the tank until it has been completely filled with water; then, with all four valves closed, the piston or the like (19, 29) is actuated in the direction corresponding to increasing the volume that is in communication with the inside of the tank, thereby subjecting said volume to a reduction in pressure and expelling from the balls at least part of the air contained therein, which air is collected in the upper chamber of the tank and in the capacity in communication with said chamber; after which the first and fourth valves (4, 15) are opened so as to fill all of the volumes in question with water, thereby impregnating with water the balls that have been at least partially emptied of air, and the piston or the like is actuated in the direction opposite to the preceding direction to return it to its initial position, the cycle of the two above-defined steps implementing a go-and-return stroke of the piston optionally being repeated one or more times.
7. An impregnation method according to claim 6, characterized in that if the volume of the cylinder capacity of the pump is written V and if the volume at atmospheric pressure of the air contained in the cells of the charge of balls inserted into the tank is written v, then V is given a value that is greater than 4v.

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