FR2681934A1 - METHOD AND INSTALLATION FOR FILLING LIQUID GAS BOTTLES AND FOR MONITORING SUCH BOTTLES AFTER FILLING. - Google Patents

Abstract

The subject of the present invention is a method and an installation for filling liquid gas bottles (3) and for controlling the weight of said bottles after filling, comprising a weighing unit (13), bottles (3) located upstream of a carousel (2) and a programmable automaton (15) connected to said weighing unit (13) and to said carousel (2) and making it possible to determine the weight of gas for filling each weighed bottle (3) as a function of values reference stored in the memory of said programmable controller (15) and control through said controller, the control of the filling valve of this bottle (3) arrived on one of the filling stations (2a) of the carousel (2); after filling, the filled bottle (31) is weighed and the weight of gas delivered during filling of the bottle (3) is corrected through said programmable controller (15).

Description

Method and installation for filling bottles with liquid gas and

  for checking said bottles after filling.

DESCRIPTION

  The subject of the present invention is a method and an installation for filling bottles of liquid gas and

  control of said bottles after filling.

  The technical sector of the invention is that of filling and control operations for the conditioning of bottles of liquid gas such as liquid air, liquefied petroleum gas (LPG) or the like. liquid gas comprising an open loop bottle conveyor, the ends of which lead to a circular carousel for continuous filling. Such installations include, for example upstream of said carousel, stations for loading and unloading bottles, for ejecting bottles to be re-tested, to repaint or repair and, downstream of said carousel, a station for checking the weight of the filled bottles, a capping and level control station and for gas leaks, more particularly with regard to petroleum gas

  liquefied and for understandable security reasons.

  In particular in the context of the marketing of such a gas, the used bottles returned to the distribution circuit enter the filling center and in some cases, with a residue

gas.

  Currently, the bottles are filled by filling the bottle during filling without taking into account the amount of residual gas that it can contain. After filling, the total weight of the bottle is checked by sampling and deducted as a function tare weight, the weight of gas in the bottle. If the gas weight does not correspond to the previously defined filling criteria taking into account a tolerance range, the underloaded or overloaded cylinder is removed from the circuit for return to the distribution network and is directed to a station o it is brought into conformity with the standard and the conditions of

  previously defined marketing.

  We understand that such a practice means that we put back on the market a certain quantity of gas (the remainder) previously invoiced and that we re-charge this gas when the

  newly filled bottle in the distribution circuit.

  Also, when checking the filling of the bottles from the carousel, no means of correcting the filling is provided after finding the non-conformity of the bottles passing through the control post with regard to the standard in force and the

pre-established criteria.

  The present invention aims to make improvements to liquid gas filling centers with the aim of automatically, systematically and continuously carrying out the operations of filling and checking bottles, taking into account the drawbacks of the centers currently in operation and the

inevitable variable parameters.

  An objective of the invention is to fill the gas bottles returned to the distribution circuit taking into account the remainder that the bottles are likely to contain and to fill the bottles by injecting the additional gas determined according to the theoretical quantity previously defined as a function of the nominal weight, a safety margin and a

pre-established tolerance.

  Another objective of the invention is to carry out, during the control of the quantity of gas injected into the bottle, a correction when loading the following bottles by acting on the filling means, so that the bottles from the carousel of filling are part of previously defined weight criteria, taking into account the standard in force and a

pre-established tolerance.

  These objectives are achieved by the installation for filling bottles with liquid gas and controlling the weight of said bottles after filling, comprising a station for loading empty bottles and a station for unloading full bottles connected to a conveyor forming an open loop on which bottles are put into circulation, a labeling station for said bottles, the ends of said conveyor leading to a circular filling carousel comprising a plurality of scales juxtaposed at its periphery, and a general gas inlet from which branches each leading to a scale to constitute a filling station comprising at least one remote-controlled valve and a control weighing unit located downstream of said carousel to control the filling of bottles from said carousel, characterized in that it further comprises a bottle weighing unit before filling located upstream of said carousel and a programmable automaton and interconnection means between said automaton and said weighing unit and between said automaton and said carousel and making it possible to determine the weight of gas for filling each weighed bottle, function of reference values stored in the memory of said programmable automaton, and control through said automaton the piloting of said remote-controlled valve and the filling of this bottle arriving at one of the filling stations of the carousel In an installation with gas cylinders equipped a label or coding comprising in particular a tare code, said weighing unit comprises a reader of said tare code, which reader is connected to said programmable controller, which takes into account the gross weight of the bottle, namely the tare increased by the weight of the gas remaining in the bottle, compare said gross weight to the tare , makes the difference and compares the resulting value with said reference value stored in its memory, it then makes the difference between said resulting value and said reference value to determine the weight of gas to be received by the bottle. Advantageously, said filling stations of the carousel comprise electronic scales comprising a program, each of which scales being connected to said automaton to control the filling of the bottle as a function of the weight of gas defined by

said automaton.

  These objectives are also achieved by the method of filling liquid gas cylinders and of controlling the weight of said cylinders after filling, characterized by the following operations: the reference values relating to the weight of gas from a full bottle and / or the weight of a full bottle of gas is weighed by means of a weighing unit located on the circuit of a gas bottle conveyor and upstream of a filling carousel comprising electronic scales, the bottles to be filled circulating on said conveyor and for each of the bottles passing through said weighing unit, the resultant weighing value is entered which is taken into account by said programmable controller, which compares this value with said stored reference value in its memory, makes the difference between the two values and commands, through one of the electronic scales of the carousel, the repl emitting of said bottle arriving on said electronic scale, depending

  the weight of gas defined by said programmable controller.

  In one application of this process, the gas bottles are equipped with a label or a coding comprising in particular the tare weight of the bottle, and to determine the weight of gas that a bottle must receive, by means of the automaton and from its peripheral systems, the tare carried on the label is read; the gross weight of the bottle is weighed, that is to say the tare increased by the residual gas contained in said bottle; we compare the gross weight to the tare read, we make the difference between these two values, we subtract this result from the reference value of the gas weight,

  and the resulting value of gas to be delivered is determined.

  Advantageously, the gas bottles are fitted with a label or coding comprising a bar code, and: the gas bottle is weighed on an electronic scale connected to said programmable controller which receives the information given by the scale and, we read the tare by means of an electronic reader and we send

  the tare value read from said programmable controller.

  The weight of the gas cylinders from said carousel is checked by means of a weighing unit located on the circuit of said conveyor and downstream of said carousel and the overfilled or underfilled bottles are ejected on secondary routes, and according to the invention: a theoretical weighing precision value is chosen which is stored in said programmable controller; for each electronic scale of the carousel, a number of filled bottles is checked on an electronic scale of said filling carousel; the weight values of said bottles given by said weighing unit are entered and these values are sent to said programmable controller; these values are compared with said reference value of the weight of gas of a full cylinder, to determine the difference in weight between said reference value and the values given by said weighing unit; we average the values of the weight differences given in the previous step, we compare the average value of the weight differences of said theoretical precision value through said programmable controller, which makes the difference between these two values and gives the value average weighing error of said scale of the carousel; and the weight of gas delivered during filling of the cylinder is corrected through said programmable controller by adding or subtracting said average weighing error value when weighing the next gas bottle placed in the filling position on

  said electronic scale of the carousel.

  The applications of the invention extend to the filling of all liquefied gases such as air, petroleum gas or any other similar gas. The advantages of the invention lie in particular at three levels: improvement of production management by viewing and memorizing all the reports, editing of listings, totals, averages, comparative ratios in real time and automatically , improvement and maintenance for automatic fault detection, management, fault status, troubleshooting assistance, spare parts management, increased operational safety through better accuracy and continuous control of the weight of the bottles during filling in order to avoid overfilling (danger of explosion), systematic and continuous gas control of all other control operations, such as the detection of leaks from level gas, the retest

  The following description refers to the accompanying drawings of a

  non-limiting example of implementation of the method according to the invention, applied to an installation for filling bottles of liquefied petroleum gas called GP L. FIG. 1 is a schematic top view of such a filling installation, FIG. 2 is a block diagram / block diagram of the part of said installation which includes the improvements according to

the invention.

  Reference is first made to FIG. 1 of the drawing. Said installation comprises, in known manner, a chain conveyor 1 forming an open loop, the ends 1a / 1b of which lead to a carousel 2 Said conveyor 1 is for example a conveyor with mechanical chains on which 3/31 gas cylinders are

placed for transport.

  The carousel 2 is circular and is constituted by a metallic structure arranged horizontally and mounted in rotation on a circular circuit resting on the ground The rotation drive is

  continuously produced by a gear motor 4 and a friction wheel 5.

  Such a carousel is perfectly known and comprises at its periphery a series of flip-flops 2 a juxtaposed on which are placed the gas cylinders during their filling by a gas supply network comprising a central general inlet on a rotating joint 6, coaxial with the axis of rotation of the circular structure and terminating in the carousel, for example from below, from which lead branches 7 equipped with a remote-controlled filling valve 7 a and their equipment

  security with such carousels.

  This installation also includes a loading station 8 from which are placed in the circuit the empty bottles 3 with or without a gas residue Downstream of this station 8 and on the conveyor circuit 1 is mounted a station 9 for reading the date of re-testing the bottles and the ejection of the bottles to be re-tested by means of a pneumatic ejector 9 a which moves the selected bottle perpendicular to the conveyor to put it on a bypass roller range 10 On this bypass is located a taring and labeling 11 and upstream thereof a so-called "spacer" scrolling regulator 12 Downstream of said station 9 and upstream of the carousel 2, is located according to the invention, a continuous weighing unit 13 integrated into said audit conveyor 1, which is connected by connecting lines 14 to a programmable automaton 15 itself connected to said carousel 12 by a multiconductor line 16 ending, for example, from above at by means of a rotating joint, and coaxially at

carousel 2.

  In known manner, the conductors of line 16 are connected to the organs of the carousel. According to the invention, the scales receiving the bottles for filling are electronic and are therefore connected to said automaton, which controls said valves.

filling 7 a.

  A spacer 12 is mounted upstream of the weighing unit 13.

  The end of the conveyor 1 tangentially tangent to the periphery of the carousel 2 and comprises a pneumatic ejection station 17 for the bottles 3 circulating on the conveyor, for placing these bottles on the electronic scales 2 a composing the filling stations of the carousel The translation bottles is made

  in a direction substantially orthogonal to the carousel 2.

  The bottles filled on the filling stations of the carousel 2 are returned to the conveyor circuit 1 of which

  the end 1b ends substantially orthogonally to said carousel.

  Downstream of the latter is a continuous weighing control unit 18 integrated into said conveyor 1, which comprises a spacer 12 upstream. Said unit 18 is connected by a line 18 to said audit.

programmable controller 15.

  Downstream of the control unit 18, there is a station for ejecting overfilled or underfilled bottles 19, which is controlled by said automaton 15 through said control unit 18 Said station

  19 has a first pneumatic ejector 19 has bottles under

  filled, which moves them perpendicular to the conveyor 1 on a roller track 19 b and a second pneumatic ejector 19 c of the over-filled bottles which move the said bottles on a

  second roller track 19 d parallel to track 19 b.

  Downstream of station 19 is a gas leak detection station 20 located at the right of the bypass 10 which connects the circuits

  "filling" lc and "'control" ld of said conveyor 1.

  Finally, the controlled and compliant bottles are transported by the conveyor 1 and placed on a roller shelf 21, awaiting their evacuation to the distribution networks after being

temporarily stored.

  The bottles 3 placed on the conveyor 1 and comprising a label or a code, coming from station 9, are transported by said

  conveyor directly to the weighing unit 13.

  The unlabeled or non-coded bottles are sent to the taring and labeling or coding station 11 o they are coded or equipped with a label adopting for example the shape of a square or a circle and placed around the neck valve or valve on the bottle. In order to ensure their lifespan of around twenty years and allow them to withstand the mechanical and chemical stresses existing in an LPG filling installation for example,

  labels are made by photo-composition and in polyethylene.

  In order to allow entry and automatic transmission of the retest date and / or tare, coding

  used is a bar code with concentric circles.

  The design of the label is such that the coding is, after mounting the label on the bottle, substantially coaxial with

  tap or valve on the bottle.

  Thus, all the stations of the installation requiring the reading of the retest date or the tare, are equipped with a laser reader placed at the right of the post considered and above the passage of the

  bottle moved by conveyor 1.

  Given the circular form of the code, part of the code

  bar moves parallel to the direction of travel of the bottle.

  The reading direction is therefore perpendicular to the scrolling direction, the reader used is a linear scanner whose scanning is

perpendicular to the conveyor.

  The depth of field of the reader is chosen to allow the

  reading of codes on bottles of minimum or maximum height.

  The weighing unit 13 comprises an electronic scale 13 a on which the bottles are placed for filling. Said scale 13 a is located substantially at the level of the conveyor 1 to take care of the bottles 3 circulating thereon The reader

  laser 13 b is arranged at the top of said unit,

  above the scale 13 a, leaving a space between them for the passage of the bottle 3 The laser reader 13 b and the electronic scale 13 a of said weighing unit 13 are connected to said programmable controller, which can be placed in a protected enclosure , in a non-hazardous area Thus the machine is located a few meters from the filling installation which is in a so-called hazardous area due to the handling of LPG cylinders and of nature

explosive of this gas.

  The laser reader 13b is placed in a pressurized box which also contains an electronic reading system.

  programmable 15 is also in a pressurized cabinet.

  According to the invention, the determination of the remainder of gas contained in a bottle 3 coming from station 9 is carried out continuously by applying the following method, with reference to the block diagram of FIG. 2: one stores in the memory of a programmable controller 15 the reference values relating to the weight of gas from a bottle 3 full of gas and / or to the weight of a bottle full of gas; a bottle 3 is weighed by means of the electronic scale 13 a of said weighing unit 13 in order to capture the weighing information read by said electronic scale and relating to the gross weight of the bottle 3, that is to say the increased tare of the gas residue, information that is sent to the machine 15; the tare carried on the label of the bottle 3 is read by means of said laser reader 13 b, this information is entered and it is sent to said automaton 15, which first makes the difference: gross weight minus tare read, for determine the gas balance and then compare this value obtained with the reference value stored in its memory and makes the difference between the balance value and said reference value to determine the quantity of gas that must

  receive the bottle arrived on a scale 2 has carousel 2.

  All these values are given by weight.

  The communication protocols are for example connected by serial connections of the RS 232 type. The flip-flop 13 a of the unit 13 is slave and is interrogated using the communication protocol each time a bottle 3 is passed through.

  the automaton 15, once it has stabilized on said rocker.

  Communication between the laser reader 13b and the programmable controller 15 is carried out by the RS 232 type serial link. A detector 13 C placed upstream of the weighing unit 13 sends a signal to the controller during the passage of a bottle 3, which triggers the reading of the laser beam and puts it itself on standby for reception of the value to be read When the reader 13 b detects the code and deciphered it, it transmits the value read and starts in position of

  reception of the next reading order.

  The weighing unit 13 may further comprise an input keyboard 13 d which replaces the laser reader 13 b and possibly allowing an operator to enter the tare or the total weight of the

bottles 3.

  The electrical connection with the programmable controller 15 is of the intrinsic type with a cable length determined for example of the order of 250 meters. A remote display can be optionally connected

PLC audit.

  The value relating to the weight of the gas which the bottle 3 weighed at station 13 must receive is determined by the automaton 15, is then sent to the carousel 2 through the program of the electronic scale 2a of said carousel, on which said said arrived

  bottle 3 previously weighed by unit 13.

  The machine 15 takes into account the bottle 3 weighed at station 13 until it is placed on the electronic filling scale 2a in order to assign the value determined during weighing at station 13 to the bottle weighed at this station, and controls the LPG filling valve 7a according to the weight value it has

previously determined.

  Of course, various parameters are entered into the memory of the programmable logic controller 15 which are in a known manner exploited by the computer and such as: the type of bottle, the tare

  minimum, maximum tare, target weight, tolerance value.

  The process is repeated for each of the bottles 3 which are

present at the weighing unit 13.

  The bottles 31 filled with gas, coming from the filling station in the order of admission to the carousel 2, are put on hold for weight control at station 18 comprising a second unit

  weighing analogous to the unit 13 previously described.

  The weighing unit 18 thus comprises an electronic scale 18 a situated substantially at the level of the conveyor 1, a laser reader 18 b

  located on the path of the bottles and above the passage of them

  here therefore above the flip-flop 13 a, a detector of the presence of

bottles 18 c.

  It can also include an input keyboard 18 d All these

  devices are connected to the programmable controller 15.

  Consequently, for each bottle 31 which passes the weight control to station 18, one can associate the station of carousel 2 which has

carried out the filling.

  On the other hand, for the same filling station of the carousel 2, it is possible to control different bottles filled during the

rotation of said carousel.

  Thus and according to the invention, the method is applied with reference to the block diagram of FIG. 2: a theoretical weighing precision value is chosen which is entered into the memory of said programmable controller 15; for each of the electronic scales 2a of the carousel 2, a number of bottles 31 is checked, filled on an electronic scale of said carousel; the weight values of said bottles 31 given by said weighing unit 1 & are entered and these values are sent to said automaton; these values are compared with said theoretical precision reference value of the weight of gas of a full cylinder, to determine by difference the difference in weight between said reference value and the values given by said weighing unit; the values of the weight differences given in the previous step are averaged; it then compares the average value of the weight differences to said theoretical precision value through said programmable controller 15, which makes the difference between these two values and gives the average value of weighing error of said scale 2a of the carousel 2 ; and the weight of gas delivered during filling of the bottle 3 is corrected, through said programmable controller 15, by adding or subtracting said average weighing error value when the next bottle 31 placed on said scale is weighed

electronics 2 has a carousel.

  This correction is only possible if the standard deviation of the values is not too large. In the opposite case, the programmable controller deletes the filling station from carousel 2 and an indication of

  fault is displayed on a supervision screen 22.

  The removal of the filling station 2 a is carried out without interrupting production, the carousel 2 continuing to operate

with one less post.

  As for the weighing unit 13, the communication protocol is linked for example by a serial connection of RS 232 type. The computer performs the tares and resets which allow

  get rid of the mechanical part of the rocker 18 a.

  The input keyboard 18 d can replace the laser reader 18 b and possibly allow the operator to enter the tare or the total weight of the bottles 31, so that the machine 15 compares the target weight with the weight read The link electric with the automaton 15 is of the intrinsic type with a cable length of the order of 250 meters. The flip-flop 18a is a slave and is interrogated by the communication protocol on each passage of the bottle by the controller 15 after

  that it has stabilized on the scale.

  Communication between the laser reader 18b and the programmable controller is carried out by a serial link of RS 232 type. The detector 18c warns the controller 15 of the passage of a bottle, triggers the reading of the laser beam and puts it itself awaiting receipt of the value to be read When the laser reader 18 ba detects the code and deciphered it, it transmits the value read to the controller 15 and goes into the position for receiving the next read order. These means make it possible in particular to read the tare of the bottle worn on the bar code label and to record these values for production management operations. The correctly filled bottles 31 continue on their way

on the conveyor 1.

  The overfilled and underfilled bottles are placed on said areas 19 b / 19 d, as previously explained in

reference to figure 1.

  Of course, without departing from the scope of the invention, the parts which have just been described by way of example may be replaced by a person skilled in the art by equivalent parts.

fulfilling the same function.

Claims (6)

  1 Installation for filling bottles with liquid gas (3) and controlling the weight of said bottles (31) after filling comprising a station for loading empty bottles (8) and a station for unloading full bottles (21) connected to a conveyor (1) forming an open loop on which said bottles (3/31) are circulated, a labeling station (11) of said bottles, the ends (la / lb) of said conveyor (1) leading to a carousel of circular filling (2) comprising a plurality of scales (2 a) juxtaposed at its periphery, and a general gas inlet (6) from which branch outlets (7) each leading to a scale (2 a) to constitute a filling station comprising at least one remote-controlled valve (7 a) and a control weighing unit (18) located downstream of the carousel (2) to control the filling of the bottles (31) from said carousel (2) c characterized in that it further comprises a weighing unit (13) of the bottles (3) before filling, located upstream of said carousel (2) and a programmable automaton (15) and means of interconnection between said automaton (15 ) and said weighing unit (13) and between said automaton (15) and said carousel (2) and making it possible to determine the weight of gas for filling each weighed bottle (31) as a function of reference values stored in the memory of said programmable controller (15) and control through said controller the piloting of said remote-controlled valve (7a) and the filling of this bottle (3) which has reached one of the   filling stations (2 a) of the carousel (2).   2 Installation according to claim 1, the gas cylinders of which are equipped with a label or coding comprising in particular a tare code, characterized in that said weighing unit (13) comprises a reader (13 b) of said code of tare, which reader is connected to said programmable controller (15) which takes into account the gross weight of the bottle (3), ie the tare increased by the weight of the gas remaining in the bottle (3), compares said gross weight to the tare, makes the difference and compares the resulting value with said reference value stored in its memory, it then makes the difference between said resulting value and said reference value to determine the weight of gas to be received the bottle (3).   3 Installation according to any one of claims 1 and   2, characterized in that said filling stations of the carousel (2) comprise electronic scales (2 a) comprising a program, each of which scales being connected to said automaton (15) to control the filling of the bottle (3) according to the   weight of gas defined by said automaton.   4 Method for filling bottles (3) with liquid gas and controlling the weight of said bottles (31) after filling, characterized by the following operations, the reference values relating to the weight are stored in the memory of a programmable controller (15) gas from a full bottle (3) and / or the weight of a bottle (3) full of gas; weighing is carried out by means of a weighing unit (13) located on the circuit of a conveyor (1) for gas cylinders (3) and upstream of a filling carousel (2) comprising electronic scales (2 a ), the bottles to be filled (3) circulating on said conveyor (1) and for each of the bottles (3) passing through said weighing unit (13) the resultant value of the weighing is entered which is taken into account by said programmable controller ( 15), which compares this value with said reference value stored in its memory, makes the difference between the two values and controls through one of the electronic scales (2 a) of the carousel (2) the filling of said bottle (3) arriving on said electronic scale (2 a) depending on the weight   gas defined by said programmable controller (15).   Method according to claim 4, according to which the gas bottles (3) are fitted with a label comprising in particular the tare weight of the bottle, characterized in that to determine the weight of gas that a bottle (3) must receive: the tare carried on the label the gross weight of the bottle (3) is weighed, that is to say the tare increased by the remainder of gas contained in said bottle; the gross weight is compared to the tare read, the difference is made between these two values, this result is subtracted from said reference value of the weight of gas,   and the resulting value of gas to be delivered is determined.   6 Method according to any one of claims 4 and 5   according to which the gas bottles (3) are fitted with a label or coding comprising a bar code, characterized in that: the gas bottle (3) is weighed on an electronic scale (13 a) connected to said programmable automaton (15) which receives the information given by the scale and, the tare is read by means of an electronic reader (13b) and   sends the tare value read to said programmable controller (15).   7 Method according to any one of claims 4 to 6,   according to which the weight of the gas bottles (31) from said carousel (2) is controlled by means of a weighing unit (18) located on the circuit of said conveyor (1) and downstream of said carousel (2) and ejected on secondary tracks (19 b / 19 d) of the conveyor (1) the overfilled or underfilled bottles (31), characterized in that: a theoretical weighing precision value is chosen which is stored in said programmable controller (15); for each electronic scale (2 a) of the carousel (2) a number of bottles (31) filled on an electronic scale (2 a) of said filling carousel (2) is checked; the weight values of said bottles (31) given by said weighing unit (18) are entered and these values are sent to said automaton (15); these values are compared with said reference value of the weight of gas of a full cylinder (31), to determine the difference in weight between said reference value and the values given by said weighing unit (2 a); the values of the weight deviations given in the previous step are averaged; the mean value of the weight deviations of said theoretical precision value is compared through said programmable controller (15), which makes the difference between these two values and gives the mean value of weighing error of said scale (2 a) of the carousel (2); and the weight of gas delivered during filling of the bottle (3) is corrected through said programmable controller (15) by adding or subtracting said average weighing error value when weighing the gas bottle (3) next placed in the filling position on said electronic scale (2 a) of the carousel (2).