EP0034098B1 - Process for filling liquefied-gas bottles and installation for carrying it out - Google Patents

Abstract

1. Process of filling liquefied-gas bottles capable of containing a random residual mass, the said process permitting the quantity of liquefied gas in the bottles to be limited between a maximum quantity QMax and a minimum quantity QMin while having an average weight greater or equal to QNom corresponding to the nominal quantity of gas, characterized in that it consists in : - selecting, before filling the bottles, those which contain a residual quantity of gas less than QMax - QNom (at 3, 3a) ; - filling the said selected bottles with the same quantity of gas QNom +- epsilon (epsilon representing the difference between the nominal weight and the average weight of the gas actually contained in the bottles after filling, which is determined periodically) (at 5) ; - removing, after filling, the bottles containing a quantity of gas greater than QMax and the bottles containing a quantity of gas less than QMin (at 12-14) ; - periodically checking the conformity of the charges of gas contained in the bottles with the specifications (at 16).

Description

The present invention relates to a new method for filling liquefied petroleum gas (G.P.L.) cylinders, in particular butane and propane cylinders. It also relates to an installation for the implementation of such a process.

The bottles are filled in factories and in specialized installations which include a handling circuit and one or more filling devices which can be grouped together on a filling carousel.

After use, these bottles come back from customers with a rest of G.P.L. of variable weight, generally zero or very low. But sometimes this residue can randomly reach one or more kilograms.

• - d'une part, la garantie d'un poids de G.P.L. dans chaque bouteille de gaz, qui soit en moyenne au moins égal à la charge nominale de la bouteille.

Regulations, particularly in France, impose on suppliers of liquefied gas packaged in bottles (butane and propane gas) two obligations which must be periodically verified to be fulfilled:

• - on the one hand, the guarantee of a weight of LPG in each gas cylinder, which is on average at least equal to the nominal load of the cylinder.

• - d'autre part, pour des raisons de sécurité, le remplissage du récipient en G.P.L. ne doit pas dépasser un maximum qui dépend du type de G.P.L. (butane ou propane) et du volume du récipient.

In France, for standard 13 kg cylinders, the average gas weight of each cylinder must be at least 13 kg. The percentage of bottles weighing, full, less than 99% of the gross weight must not exceed 4%, which, due to the dead weight of the empty bottle, corresponds to an under-filling of approximately 2%.

• - on the other hand, for safety reasons, the filling of the container with LPG must not exceed a maximum which depends on the type of LPG (butane or propane) and the volume of the container.

Thus, in France, the bottles of G.P.L. must be completed in G.P.L. liquid so that at 50 ° C, this G.P.L. occupies no more than 97% of their interior volume (which, for standard 13 kg cylinders, corresponds to a gas weight of 13.7 kg maximum).

In order to facilitate filling, the gross weight of each full bottle is written on the dome of the bottle or on its tap.

• - arrivée de la bouteille sur un circuit de manutention amont,
• - orientation de la bouteille,
• - introduction de la bouteille sur l'appareil d'emplissage qui peut éventuellement faire partie d'un ensemble de plusieurs appareils d'emplissage montés sur un carrousel d'emplissage,
• - branchement de la bouteille sur le circuit d'alimentation en G.P.L. par l'ouvrier placé à l'entrée de l'appareil d'emplissage,
• - ouverture du robinet de la bouteille,
• - lecture du poids brut et affichage de ce poids sur l'appareil d'emplissage par l'ouvrier,
• - remplissage, pesée et arrêt automatique du remplissage lorsque le poids brut est atteint,
• - fermeture du robinet et débranchement du robinet,
• - éjection de la bouteille pleine sur le circuit de manutention aval,
• - départ de la bouteille pleine sur un circuit de manutention,
• - contrôle périodique du remplissage des bouteilles.

The most generally used filling process currently comprises the following operations, some of which can be mechanized and take place in a possibly different order:

• - arrival of the bottle on an upstream handling circuit,
• - orientation of the bottle,
• - introduction of the bottle onto the filling device which may possibly be part of a set of several filling devices mounted on a filling carousel,
• - connection of the bottle to the LPG supply circuit by the worker placed at the entrance to the filling device,
• - opening of the bottle tap,
• - reading of the gross weight and display of this weight on the filling device by the worker,
• - filling, weighing and automatic filling stop when the gross weight is reached,
• - closing the tap and disconnecting the tap,
• - ejection of the full bottle on the downstream handling circuit,
• - departure of the full bottle on a handling circuit,
• - periodic control of bottle filling.

With such a process, even on an automated carousel, the production rate is limited to the possibilities of the worker placed at the entrance of the filling carousel, because this worker is rarely able to reach the rate of 1,300 bottles / hour. in instant production and rarely more than 5,000 bottles / hour on average at cruising speed, 8 hours / day.

• - orientation de la bouteille,
• - ouverture du robinet,
• - branchement de la bouteille sur le circuit d'alimentation,
• - lecture du poids brut inscrit sur la bouteille,
• - affichage du poids brut sur l'appareil d'emplissage.

The worker placed at the entrance to the filling machine must, in fact, perform several operations:

• - orientation of the bottle,
• - tap opening,
• - connection of the bottle to the supply circuit,
• - reading of the gross weight written on the bottle,
• - display of gross weight on the filling device.

In particular, the reading of the gross weight written on the bottle and its display on the filling device by the worker placed at the entrance of the carousel limit the filling rate.

• - erreur initiale d'inscription du poids brut sur les bouteilles,
• - erreur de lecture de ce poids brut par l'ouvrier placé à l'entrée de l'appareil d'emplissage,
• - erreur d'affichage par cet ouvrier sur l'appareil d'emplissage,
• - erreur de l'appareil d'emplissage,
• - erreur de lecture du poids brut et de la pesée au contrôle périodique.

On the other hand, several types of errors can occur at different stages of the filling process:

• - initial error in recording the gross weight on the bottles,
• - error in reading of this gross weight by the worker placed at the entrance to the filling device,
• - display error by this worker on the filling device,
• - error in the filling device,
• - error in reading the gross weight and weighing at the periodic check.

It goes without saying that the errors of the worker placed at the entrance to the filling machine increase with the production rate.

The present invention provides a new method of filling liquefied gas bottles which may still contain a random quantity of residual gas and which allows, in a simple and rapid manner, filling of liquefied gas bottles.

This process is the result of a judicious combination of various operations allowing automation of filling while reducing the risk of errors.

• - sélectionner, préalablement au remplissage des bouteilles, celles qui contiennent une quantité de gaz résiduel inférieure à Q_Max - Q_Nom,
• - remplir lesdites bouteilles sélectionnées d'une même quantité de gaz Q_Nom ± ε (ε représentant la différence entre le poids nominal et le poids moyen de gaz réellement contenu dans les bouteilles après remplissage, lequel est déterminé périodiquement),
• - écarter, après remplissage, les bouteilles contenant une quantité de gaz supérieure à Q_Max et les bouteilles contenant une quantité de gaz inférieure à Q_Min,
• - contrôler périodiquement la conformité des charges de gaz contenues dans les bouteilles aux spécifications.

The method proposed by the present invention makes it possible to limit the amount of liquefied gas contained in the bottles between an amount maximum Q _Max (13,700 kg in the case of a 13 kg bottle) and a minimum quantity Q _Mln (12,700 kg in the case of a 13 kg bottle) while having a higher average weight or equal to Q _Name corresponding to the nominal quantity of liquefied gas that the bottles must contain (13 kg in the case of a 13 kg bottle). The filling process according to the invention consists in:

• - select, before filling the bottles, those containing a quantity of residual gas less than Q _Max - Q _Nom ,
• - fill said selected bottles with the same quantity of gas Q _Nom ± ε (ε representing the difference between the nominal weight and the average weight of gas actually contained in the bottles after filling, which is determined periodically),
• - discard, after filling, the bottles containing an amount of gas greater than Q _Max and the bottles containing an amount of gas less than Q _Min ,
• - periodically check the compliance of the gas charges contained in the cylinders with the specifications.

According to an important characteristic of the process according to the invention, before the bottles are introduced into the filling apparatus, those which contain a quantity of residual gas greater than Q _Max - Q _{Nom '} are removed _.

The detection of bottles containing a residue greater than this maximum can be carried out, for example, by the level detection technique by gamma rays or by ultrasound.

The bottles containing a residue greater than the defined maximum are ejected on a waiting circuit from where they are taken up and filled according to the previous process. It is also possible to introduce these bottles into the filling device used for implementing the process according to the invention, if the possibility of a display is additionally provided on the filling device. manual.

According to another important characteristic of this process, after having discarded those which have a residue greater than Q _Max - Q _Nom , the bottles are filled with the same determined quantity of gas.

The method according to the invention is implemented in a filling apparatus in which the filling stations with manual display are advantageously replaced by automatic filling stations adjusted to deliver a determined quantity of gas corresponding to the quantity of gas Q _Name ± ε to be introduced into each bottle.

It is easy to see the simplification brought by this new process in bottle filling operations. In particular, the operation of reading and displaying the gross weight which the operator placed at the entrance to the filling apparatus had to perform, is eliminated.

This operation is often the cause of errors on the part of the worker placed at the entrance to the filling machine, because this worker only has a very short time to read the gross weight written on the bottle. and display it on each filling station.

• - erreur de lecture du poids brut par l'ouvrier placé à l'entrée de l'appareil d'emplissage,
• - erreur d'affichage du poids brut par cet ouvrier sur les postes d'emplissage.

Thanks to the process according to the invention, two risks of errors are eliminated:

• - error in reading the gross weight by the worker placed at the entrance to the filling machine,
• - display error of the gross weight by this worker on the filling stations.

According to another arrangement of the invention, after filling, the bottles containing a quantity of gas greater than Q _Max and the bottles containing a quantity of gas less than Q _M are discarded. Detection of bottles that are too full and / or under -filled is carried out, for example, by the level detection technique by gamma rays.

These non-compliant bottles are evacuated on a waiting circuit from where they are taken to put the weight of gas that these bottles contain in compliance with the regulations.

We check the weight of the filled bottles periodically to ensure that the weight of gas contained in the bottles complies with regulations.

• - arrivée de la bouteille sur un circuit de manutention,
• - détection des bouteilles dont le reste est supérieur au maximum défini,
• - éjection de ces bouteilles sur un circuit d'attente,
• - orientation de la bouteille avant son introduction sur l'appareil d'emplissage,
• - introduction de la bouteille sur l'appareil d'emplissage,
• - branchement de la bouteille sur le poste d'emplissage et ouverture du robinet,
• - annulation automatique de la tare,
• - remplissage, pesée, arrêt automatique du remplissage,
• - fermeture du robinet et déoranchement automatique de ce robinet,
• - éjection automatique de la bouteille pleine sur le circuit de manutention aval,
• - transport de la bouteille pleine sur ce circuit de manutention aval,
• - détection et éjection des bouteilles insuffisamment remplies,
• - détection et éjection des bouteilles trop remplies.
• - contrôle périodique de poids de gaz contenu dans les bouteilles.

The process for filling liquefied gas bottles according to the invention comprises the following operations which can all be automated, since the worker is no longer necessary at the entrance to the carousel:

• - arrival of the bottle on a handling circuit,
• - detection of bottles whose rest is greater than the maximum defined,
• - ejection of these bottles on a waiting circuit,
• - orientation of the bottle before its introduction on the filling device,
• - introduction of the bottle on the filling device,
• - connection of the bottle to the filling station and opening of the tap,
• - automatic tare cancellation,
• - filling, weighing, automatic filling stop,
• - closing of the tap and automatic disconnection of this tap,
• - automatic ejection of the full bottle on the downstream handling circuit,
• - transport of the full bottle on this downstream handling circuit,
• - detection and ejection of insufficiently filled bottles,
• - detection and ejection of overfilled bottles.
• - periodic control of the weight of gas contained in the bottles.

This weighing control operation, which is carried out periodically on a certain number of bottles at the outlet of the filling device, makes it possible to determine the average weight of gas that the bottles actually contain. after filling and to determine the average excess or lack of filling Δε by the filling stations (i.e. the difference between the nominal weight and the average weight of gas existing in the bottles).

Correcting, at the end of these periodic checks, the determined quantity of gas Q _Nom ± ε, delivered by each filling station with this excess or this average lack Δε to obtain an average weight of gas contained in the bottles after filling equal to or greater than the nominal.

The information provided by this single control, which results in an identical setting for each filling station, provides statistical certainty that the filled bottles contain an amount of liquefied gas which is in compliance with the regulations.

• - des moyens pour évacuer les bouteilles de gaz contenant une quantité de gaz résiduel supérieure à Q_Max ― Q_Nom,
• - au moins un appareil d'emplissage équipé de moyens pour délivrer une quantité Q_Nom ± e de gaz sur les postes d'emplissage,
• - des moyens pour régler sur les postes d'emplissage la quantité de gaz déterminée Q_Nom ± ε à introduire dans les bouteilles,
• - des moyens pour introduire sur chacun de ces postes les bouteilles contenant un reste inférieur à Q_Max ― Q_Nom,
• - des moyens pour connecter lesdites bouteilles à l'alimentation de l'appareil d'emplissage,
• - des moyens pour détecter, à la sortie de l'appareil d'emplissage, les bouteilles contenant une quantité de gaz supérieure à Q_Max ou inférieure à Q_Min.
• - des moyens pour déterminer l'excès ou le manque moyen de remplissage Δε dont il faut corriger la quantité Q_Nom ± ε délivréè sur les postes d'emplissage.

The invention also relates to an installation for implementing this method comprising:

• means for evacuating gas cylinders containing a quantity of residual gas greater than Q _Max - Q _Nom ,
• - at least one filling device equipped with means for delivering a quantity Q _Nom ± e of gas to the filling stations,
• - means for adjusting the filling quantity at the filling stations Q _Nom ± ε to be introduced into the bottles,
• - means for introducing onto each of these stations the bottles containing a residue less than Q _Max - Q _Nom ,
• means for connecting said bottles to the supply to the filling apparatus,
• - Means for detecting, at the outlet of the filling device, the bottles containing a quantity of gas greater than Q _Max or less than Q _Min .
• - means to determine the excess or average lack of filling Δε, the quantity of Q _Nom ± ε delivered to the filling stations must be corrected.

The invention will be illustrated without being in any way limited by the description which follows, referring to the attached drawing.

The single figure schematically illustrates the various operations involved in the filling process according to the invention.

The bottles arrive in 1 on a filling line. These bottles contain a quantity of residual gas more or less important and which is Unknown.

We remove in 2 the hat of these bottles. The latter carry in the usual way an indication of the gross weight (not shown) which corresponds to the weight that the bottle should have when it is properly filled.

We detect in 3 and eject in 3a the bottles which have a quantity of residual gas greater than Q _Max - Q _Nom (for example 700 for 13 kg bottles).

It should be noted that the percentage of bottles returning from customers with a remainder greater than 700 g (in the case of 13 kg bottles) is low and does not generally exceed 4%.

The detection of bottles containing a residue greater than the defined maximum is done, for example, by a gamma-ray emitter-detector system (not shown). These bottles are ejected on a waiting circuit 4.

The selected bottles, that is to say those which have a residue lower than the defined maximum, are introduced into a filling carousel 5. This carousel has a number of filling stations 6, each of these stations being equipped an automatic filling device 7 which can be a tare cancellation scale.

The bottles are placed on the plates 8 of these scales and the valve of these bottles is opened at 9. These valves can be opened either by machine or manually. These bottles are connected to the gas supply circuit (not shown).

The automatic scale which equips each filling station automatically delivers a determined quantity of gas which is the same for each bottle (13 kg ± s in the case of 13 kg butane bottles).

Once this quantity of gas has been delivered, the filling is stopped automatically.

After the filling is stopped, the valve of the bottle is closed and the latter is automatically disconnected (which has been shown in 10).

The full bottles are ejected on a handling circuit 11. The insufficiently filled bottles (those containing a quantity of gas less than 12,700 kg) are detected at 12, for example by a gamma-ray emitter-receiver system. Similarly, overfilled bottles (those containing a quantity of gas greater than 13,700 kg) are detected at 13. These insufficiently filled or overfilled bottles are ejected at 14 and evacuated to a waiting circuit 15 from where they are taken to put their weight in compliance with the regulations.

The weight of the filled bottles is checked periodically at 16. This control, which is carried out on a determined number of bottles, makes it possible to calculate the average weight of the gas contained in the bottles and thereby to determine the average excess or lack of gas delivered by the filling stations ( this excess or this average lack representing the difference between the nominal weight and the average weight of gas actually contained in the bottles).

It will suffice to correct for this difference the quantity of gas determined, delivered by each filling station to obtain an average weight equal to or greater than the nominal weight.

For example, if a check carried out at the exit of the carousel on a certain number of butane bottles of 13 kg gives an average weight of 13,200 kg, we will correct the weight displayed on the automatic scales (which is not necessarily equal to 13 kg since this weight may already have been the subject of a previous correction) by the difference between this average weight and the nominal weight is, in the example given, the displayed weight will be lowered by 200 g. It is naturally understood that when the filling installation is started up, the weight displayed on the automatic scales corresponds to the nominal weight of gas that the bottles must contain (i.e. 13 kg in the case of 13 kg bottles ).

This automatic scale setting ensures that the bottles are filled with an amount of gas that is in compliance with the regulations, while taking into account gas residues in the bottles and errors at the filling stations.

The bottles which have a gas residue greater than the defined maximum and which are stored on the waiting circuit 4 are taken up again to be filled by the prior process.

The bottles are introduced on a conventional filling circuit where the filling stations are equipped with scales with manual display. In this type of installation, an operator placed at the entrance to the scales, reads the gross weight written on the bottles and displays it on the scales.

We realize the advantage of the process according to the invention in terms of operating economy it allows to achieve since, with such a process, the filling rate is no longer limited to the possibilities of l man at the entrance of the carousel. This process, thanks to the simplification it brings, makes it possible to automate the various filling operations, and to achieve filling rates well above 1,300 bottles / hour.

Thus, in the perspective of a fully automated filling installation, it is conceivable to carry out mechanical corrections for the excess or average lack of filling Δε of the determined quantities of gas Q _Nom ± ε delivered by each filling station.

For this purpose, it would suffice to have a tabulator at the periodic checkpoint for the weight of the filled bottles. The latter would automatically record, at each periodic check, the actual weight of each full bottle and the gross weight of the bottle, read by the worker in charge of the check and who would display it on the tabulator. We can even consider automating this reading if the indication of gross weight can be read automatically.

The excess or the average lack of filling which must be corrected for each filling station is then determined by the tabulator. This correction can be done automatically, after each periodic check, by information transmitted from the tabulator to all the automatic scales that equip the filling stations.

Claims (2)

1. Process of filling liquefied-gas bottles capable of containing a random residual mass, the said process permitting the quantity of liquefied gas in the bottles to be limited between a maximum quantity Q_Max and a minimum quantity Q_Min while having an average weight greater or equal to Q_Nom corresponding to the nominal quantity of gas, characterized in that it consists in :

- selecting, before filling the bottles, those which contain a residual quantity of gas less than Q_Max ― Q_Nom (at 3, 3a) ;

- filling the said selected bottles with the same quantity of gas Q_Nom ± ε (ε representing the difference between the nominal weight and the average weight of the gas actually contained in the bottles after filling, which is determined periodically) (at 5) ;

- removing, after filling, the bottles containing a quantity of gas greater than Q_Max and the bottles containing a quantity of gas less than Q_Min (at 12-14) ;

- periodically checking the conformity of the charges of gas contained in the bottles with the specifications (at 16).

2. Installation for filling liquefied-gas bottles having a residual mass of gas with a quantity of gas less than Q_Max but greater than Q_Min, this installation being adapted to carry out the process according to claim 1, characterized in that the said installation comprises :

- means (3, 3a) for removing the bottles having a remainder of gas greater than a value Q_Max ― Q_Nom ;

- at least one filling apparatus (7) equipped with means for delivering a quantity Q_Nom ± ε of gas to filling stations (6) ;

- means for introducing at each one of these stations (6) the bottles containing a remainder less than Q_Max ― Q_Nom ;

- means for connecting the said bottles to the supply for the filling apparatus (7) ;

- means (8) for controlling the determined quantity of gas to be introduced into each bottle ;

- means (12-14) for removing, at the exit of the filling apparatus (7), the bottles containing a quantity of gas greater than Q_Max or less than Q_Min ;

- means (16) for determining the difference between the nominal weight of gas that the bottles should contain and the average weight of gas that they actually contain after filling.

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