EP0596815B1 - Method of renovating a gas container and such a gas container - Google Patents

Abstract

This method for renovating a gas holder comprising at least one tank (2) bounded by a peripheral rigid border (2a), into which there emerge at least one pipeline (31, 32) for supply and discharge of a gas, is characterised in that it comprises at least the following steps: - use is made of a flexible reservoir (11); - use is made of a leaktight cover (head) (12); - with the gas holder (1) unoperational and drained of its water (8) and of its gas (9), the flexible reservoir (11) is placed in the tank (2); - the flexible reservoir (11) is connected up to each pipeline (31, 32); - the leaktight cover (12) is installed by connecting it to the peripheral border (2a) of the tank; - and possibly the intermediate space (13) made up of the tank (2) and the cover (11) is coupled up to a pressurising device (14). <IMAGE>

Description

The present invention relates to a method for renovating a gasometer.

“Gasometer” means any gas tank in which the gas is not at very high pressure, but at a medium or low pressure, close to atmospheric pressure, by a higher or lower value.

Many gasometers are constituted as follows, represented in FIG. 1.

A sealed cylindrical basin 2, comprising a rigid border 2a is filled with water 8.

Two pipes 31 and 32 open into this basin above the surface 4 of the water; one 31 is a gas inlet, the other 32 a gas outlet.

A cylindrical bell 5, slightly smaller in diameter than the inside of the basin 2, is arranged coaxially with said basin, so that the lower peripheral edge 5a of the bell, surrounding its open section, is immersed in said basin.

The bell is guided along poles 10, so as to be able to move in axial translation 6, downwards or upwards, its peripheral edge always remaining more or less deeply submerged.

Thus, a confined space 7 for receiving the gas is delimited by the inner face 5b of the bell and the surface of the water 4. The latter provides sealing between this confined space 7 and the outside environment.

This arrangement makes it possible to vary the volume of the confined space 7, as a function of the volume of gas to be stored.

Today, many gasometers are old and need to be replaced, or reconditioned. The failures, often observed, are in particular a lack of tightness of the basin, generally in masonry, and strong corrosion of the bell, favored by the generally very corrosive atmosphere, due to the stored gas.

As is known, there are mainly two methods of replacing or renovating an obsolete gasometer.

The first consists in re-sealing the basin and stripping the corroded bell before applying a corrosion protection product to it, or possibly replacing it with a new bell made of a material resistant to corrosive medium. In the event of extreme obsolescence, this process can consist of a complete demolition of the obsolete gasometer and the reconstruction of a new gasometer in its place. The major drawback of this solution is that it imposes an interruption in the operation of the gasometer, throughout the duration of the renovation or reconstruction. This interruption requires either to stop the operation of the facilities to which the gasometer is connected, which can temporarily paralyze an industry, or a waste water treatment chain or even a household waste treatment unit, in the case of a biogas, that is to let escape into the atmosphere the gas intended to be stored by the gasometer, which generally strongly harms the environment.

The second method consists in making a new gasometer next to the dilapidated gasometer, to connect the second in place of the first, then to demolish the first. This method has the drawback of requiring an available location for the construction of the new gasometer and the drawback of not allowing the re-use of the gas inlet and outlet openings of the pipelines existing at the site of the obsolete gasometer. It is therefore an expensive solution and not always feasible.

The present invention remedies these drawbacks by making it possible to renovate a gasometer, without interrupting its operation for a long time and by reusing the location and certain constituent parts of the obsolete gasometer, including, in particular, the masonry and the outlets of the inlet and outlet pipes. gas.

• on dispose d'un ballon souple dont la forme et les dimensions sont adaptées à une pénétration au moins partielle, à l'état gonflé, dans le bassin, avec un raccord sur ladite canalisation ;
• on dispose d'une couverture étanche, souple ou rigide, apte à être fixée sur la bordure périphérique du bassin, dont la forme et les dimensions, en liaison avec celles du bassin, permettent de constituer un espace, dit espace intermédiaire, apte à contenir le ballon souple, à l'état gonflé ;
• le gazomètre étant hors fonctionnement est vidangé de son eau et de son gaz, on met en place le ballon souple dans le bassin ;
• on raccorde le ballon étanche à chaque canalisation d'arrivée et d'évacuation du gaz ;
• on met en place la couverture étanche, par liaison de celle-ci à la bordure périphérique du bassin ;
• et on raccorde éventuellement l'espace intermédiaire à un dispositif de pressurisation.

To this end, the method according to the invention comprises the following steps:

• there is a flexible balloon whose shape and dimensions are adapted to at least partial penetration, in the inflated state, into the basin, with a connector on said pipe;
• there is a waterproof, flexible or rigid cover, capable of being fixed to the peripheral border of the basin, the shape and dimensions of which are in conjunction with those of the pelvis, make it possible to constitute a space, called an intermediate space, capable of containing the flexible balloon, in the inflated state;
• the gasometer being out of operation is drained of its water and its gas, the flexible balloon is placed in the basin;
• the sealed balloon is connected to each gas inlet and outlet pipe;
• the waterproof cover is put in place, by connection of the latter to the peripheral border of the basin;
• and optionally connecting the intermediate space to a pressurization device.

In addition to the aforementioned advantages, this method has that of arriving at a gasometer comprising no corrodible metal part in contact with the stored gas, nor of a mechanism such as that of vertical and axial guiding of the bell of the obsolete gasometer, or of sealing to the pond water. Consequently, this solution is particularly economical not only in manufacturing and implementation, but also in use, thanks to low maintenance and a long service life.

• la figure 1 représente un gazomètre connu qui peut être rénové selon la présente invention,
• la figure 2 représente un gazomètre obtenu par rénovation du gazomètre de la figure 1, selon l'invention et,
• la figure 3 représente à échelle agrandie un détail de fixation d'une couverture souple sur une bordure rigide.

The present invention is now described, by way of nonlimiting example, with reference to the accompanying drawings in which:

• FIG. 1 represents a known gasometer which can be renovated according to the present invention,
• FIG. 2 represents a gasometer obtained by renovation of the gasometer of FIG. 1, according to the invention and,
• Figure 3 shows on an enlarged scale a detail of fixing a flexible cover on a rigid border.

The parts of the gasometer in Figure 1 retained by the renovation and therefore included in the renovated gasometer shown in Figure 2, are identified by identical references in the two figures.

As shown in FIG. 1, a gasometer which can be renovated according to the invention can in particular be constituted in the following manner.

A sealed cylindrical basin 2 is filled with water 8. This basin is generally made of masonry and its sealing is ensured by an interior waterproof coating. Two pipes 31 and 32 open into this basin, above the surface 4 of the water. One 31 is a gas inlet, the other 32 a gas outlet. A cylindrical bell 5, with a diameter slightly smaller than that inside the basin, is arranged vertically coaxially with the basin, so that the peripheral edge 5a of the bell, surrounding its open section, is immersed in the basin 2. Thus, a confined space 7 is delimited by the inner face 5b of the bell and the surface of the water 4. The bell 5 provides sealing between this confined space and the outside environment. The bell is guided by vertical rails or posts 10, against which rollers rollers 5a secured to the bell, so as to be able to move in translation, according to arrow 6, upwards or downwards. When gas arrives, the bell rises under the effect of the gas pressure, which increases the volume of the confined space. When gas is evacuated, the bell goes down, which reduces the volume of the confined space.

A method of renovating this gasometer, according to the invention, comprises the following steps.

A flexible balloon 11 is available, the shape and dimensions of which are adapted to at least partial penetration, in the inflated state, into said tank 2, with a connection on said pipes 31 and 32.

There is also a cover 12, substantially gas-tight, flexible or rigid, suitable for being fixed on the peripheral edge 2a of the basin, the shape and dimensions of which, in conjunction with those of the basin 2, make it possible to constitute a space , said intermediate space 13, capable of containing the flexible balloon (11), in the inflated state.

The gasometer is out of operation, that is to say, for example, that the inlet 31 and outlet 32 gas pipes have been closed, and the gasometer has been drained of its water 8 and of its gas 9 , removed the bell 5 and shortened the parts of the pipes 31 and 32 rising in the basin; thus, the latter is completely empty and free to access from above. The flexible balloon 11 can then be placed in the basin 2.

Next, the flexible balloon 11 is connected to each inlet 31 and outlet 32 gas pipeline. These pipes do not require any modification outside the basin.

The flexible cover 12 is then put in place, by connection of the latter to the peripheral edge 2a of the basin. This connection can be carried out by any conventional means making it possible to ensure a seal between the flexible cover 12 and the peripheral edge 2a. For example, one can maintain the outer face of the edge of the flexible cover 12 applied against the inner face of the peripheral edge 2a of the basin, by means of screws, regularly distributed over this periphery. According to this arrangement, the desired tightness is obtained by the fact that the slight overpressure still maintained in the intermediate space 13 causes the edge of the flexible cover to be placed against the rigid edge 2a of the basin.

Additionally, as shown in FIG. 3, the flexible cover 12 has an edge 21, exterior, peripheral and regularly perforated, and the edge 2a of the pelvis is provided in the upper part with a smooth 22 of tension lacing, such so that a tension lace 23 passes alternately through a perforation of the selvedge 21 and around the smooth 22 of lacing tension. This arrangement constitutes a fixing of the flexible cover 12 to the peripheral border 2a of the basin, able to resist the tension generated by an overpressure in the intermediate space 13.

For a waterproof and flexible cover 12, the last step concerns the connection of the intermediate space 13 to a pressurization device 14, making it possible to maintain in said space a set pressure or a controlled pressure.

According to the example shown in Figure 2, the pipes 31 and 32 opening into the basin 2 may be two in number, one 31 being a gas inlet, and the other 32 a gas outlet. In this case, the step of connecting the flexible balloon 11 to the pipes 31 and 32 comprises the connections 171 and 172 respectively, to each of these two pipes.

The flexible balloon shown in FIG. 1 is provided with a perforated peripheral lip 15, allowing the balloon to be fixed to the rigid peripheral border 2a of the pelvis, by lacing cooperating with the perforations of said lip and said border. This lacing can in particular be carried out by means of a lace passing alternately through a perforation of the lip 15 and around a smooth 15 'of lacing, fixed inside the peripheral border 2a of the pelvis, at an adequate height. This arrangement keeps the balloon 11 in a substantially central position in the intermediate space 13, and to prevent it from coming into direct contact with the bottom of the basin 2, on which pointed objects could exist, capable of perforating the balloon 11.

The basin 2 does not need to be watertight, as was the case in the device shown in Figure 1, but it must be airtight to facilitate the pressurization of the intermediate space 13. Consequently, if the basin is cracked, there is a flexible membrane 16 airtight and of shape corresponding to the interior surface of the basin 2. This flexible membrane 16 is placed inside the basin 2, so that it completely covers its interior surface, including its bottom. It suffices that the edge of this flexible membrane 16 is fixed to the inner upper part of the rigid edge 2a of the basin, for example by screws distributed over the periphery. The rest of the flexible membrane 16 conforms to the interior surface of the basin 2, under the effect of the slight overpressure established inside the intermediate space 13.

• le bassin 2 délimité par une bordure rigide périphérique 2a, dans lequel débouche au moins une canalisation 31 et 32 d'arrivée et d'évacuation d'un gaz ;
• un ballon souple 11 engagé au moins partiellement dans le bassin 2, et éventuellement fixé sur la bordure rigide périphérique 2a ;
• la couverture étanche 12, souple ou rigide, fixée sur la bordure rigide périphérique 2a du bassin, en constituant avec lui un espace, dit espace intermédiaire 13, contenant le ballon souple 11 ;
• au moins un raccord 171, 172 pour raccorder le ballon 11 souple à ladite au moins une canalisation 31 et 32 d'arrivée et évacuation d'un gaz ;
• une bouche 18 de raccordement de l'espace intermédiaire à un dispositif de pressurisation 14.

This renovation process results in a new gasometer comprising at least:

• the basin 2 delimited by a rigid peripheral border 2a, into which opens at least one pipe 31 and 32 for the arrival and discharge of a gas;
• a flexible balloon 11 engaged at least partially in the basin 2, and optionally fixed to the rigid peripheral edge 2a;
• the waterproof cover 12, flexible or rigid, fixed to the peripheral rigid edge 2a of the basin, constituting with it a space, called intermediate space 13, containing the flexible balloon 11;
• at least one connector 171, 172 for connecting the flexible balloon 11 to said at least one pipe 31 and 32 for the arrival and discharge of a gas;
• a mouth 18 for connecting the intermediate space to a pressurization device 14.

In addition, in certain cases, in particular when the basin 2 is cracked, the gasometer comprises a flexible membrane 16 airtight, of shape corresponding to the interior surface of the basin 2 and coating it completely.

• un lest 10 disposé sur la surface supérieure du ballon et destiné à orienter la façon dont il se déforme lorsqu'il se dégonfle et,
• une sonde à ultra-son 20, fixée à la couverture souple 12 de manière à être sensiblement en face du lest 19, apte à délivrer un signal représentatif de la distance entre la sonde et le lest correspondant à l'état de dégonflement du ballon 11.

This gasometer optionally further comprises:

• a ballast 10 disposed on the upper surface of the balloon and intended to orient the way in which it deforms when it deflates and,
• an ultrasonic probe 20, fixed to the flexible cover 12 so as to be substantially opposite the ballast 19, capable of delivering a signal representative of the distance between the probe and the ballast corresponding to the deflation state of the balloon 11 .

When the balloon 11 deflates to evacuate the stored gas, it preferably deforms under the effect of ballast 19, which tends to lower the upper wall of the balloon 11 against its internal pressure as shown in phantom in FIG. 2. The distance separating the ballast 19 from the probe 20 fixed to the flexible cover 12 is thus representative of the deflation state of the balloon 11. The signal delivered by the probe 11, representative of this distance, is therefore also representative of the deflation state of the balloon 11, that is to say of the quantity of gas stored in the gasometer.

For a flexible cover 12 of the gasometer, it is advantageous that it comprises at least an anemometer and / or a snow load sensor (not shown) delivering signals participating in the establishment of a set pressure transmitted to the pressurization. Indeed, a strong pressurization makes it possible to better resist climatic loads, whether it is wind or snow.

The operation of the gasometer thus renovated can optionally be managed automatically, for example by a programmable controller.

Claims (8)

1. Process for renovating a gasometer comprising at least one tank (2) which is delimited by a peripheral rigid edge (2a) and into which at least one pipeline (31, 32) for the intake and discharge of a gas opens, characterised in that it comprises at least the following stages:

   - there is a flexible balloon (11) of which the shape and dimensions are adapted for at least partial penetration, in the inflated state, into the tank (2) with a connection to the pipeline (31, 32);

   - there is a leaktight covering (12) which can be secured to the peripheral edge (2a) of the tank and of which the shape and dimensions, in association with those of the tank, enable a space to be formed which is known as on intermediate space (13) and can accommodate the flexible balloon in the inflated state;

   - with the gasometer (1) not operating and drained of its water (8) and of its gas (9), the flexible balloon (11) is positioned in the tank (2);

   - the flexible balloon (11) is connected to each pipeline (31, 32) for the intake and discharge of the gas;

   - the leaktight covering (12) is positioned by connection thereof to the peripheral edge (2a) of the tank; and

   - the intermediate space (13) is if necessary connected to a pressurising device (14).
2. Process according to Claim 1,
   characterised in that, since there are two pipelines leading into the tank, one (31) for the intake of gas and the other (32) for the discharge of gas, the stage in which the flexible balloon is connected to each pipeline comprises the connection to each of these two pipelines.
3. Process according to Claim 1,
   characterised in that, with the balloon (11) provided with a perforated peripheral lip (15), the stage in which it is positioned in the tank (2) is followed by a stage in which it is secured to the peripheral rigid edge (2a) by means of lacing cooperating with the perforations in the lip (15) and the edge.
4. Process according to Claim 1,
   characterised in that, since there is an airtight flexible membrane of a shape corresponding to the internal surface of the tank (2), the process further comprises the stage in which the flexible membrane is positioned inside the tank such that it completely covers its internal surface.
5. Gasometer resulting from the process according to Claim 1, characterised in that it comprises at least:

   - a tank (2) delimited by a peripheral rigid edge (2a) into which at least one pipeline (31, 32) for the intake and discharge of a gas opens;

   - a flexible balloon (11) engaged at least partially in the tank (2);

   - a leaktight covering (12) secured to the peripheral rigid edge (2a) of the tank, forming therewith a spice, known as an intermediate space (13), containing the flexible balloon (11);

   - at least one connection (171 or 172) for connecting the flexible balloon to the at least one pipeline (31, 32) for the intake and discharge of a gas; and possibly

   - an aperture (18) for connecting the intermediate space (13) to a pressurising device (14).
6. Gasometer according to Claim 5,
   characterised in that it further comprises an airtight flexible membrane (16) having a shape corresponding to the internal surface of the tank (2) and covering it completely.
7. Gasometer according to Claim 5,
   characterised in that it further comprises:

   - ballast (19) disposed on the upper surface of the balloon and intended to orient the manner in which it is deformed when it deflates;

   - a sensor (20) which is secured to the flexible covering (12) so as to be substantially opposite the ballast (19) and which can deliver a signal representing the distance between the sensor and the ballast, corresponding to the deflated state of the balloon (11).
8. Gasometer according to Claim 5,
   characterised in that it comprises at least one anemometer and/or snow charge sensor, delivering signals contributing to the establishment of a reference pressure transmitted to the pressurising device for a leaktight and flexible covering (12).

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