OPTIMISED METHOD FOR FILLING A PYROTECHNIC CHARGE AND SYSTEM IMPLEMENTING SUCH A METHOD

Abstract

A method for filling a container with a pyrotechnic charge using a filling system, said method including, when the powder is conveyed, a step of regulating the powder flow rate in which at least one powder conveyor device is brought to vibrate according to a vibration frequency control sequence, the vibration frequency being inversely proportional to the filling ratio of the container of the pyrotechnic charge.

Claims

1. A filling method for filling a container of a pyrotechnic charge using a filling, system, the filling system comprising at least: a reservoir for dispensing a pyrotechnic powder, a measuring device for measuring the pyrotechnic powder, and a powder conveyor device for conveying the pyrotechnic powder from the reservoir to a basin of the measuring device, wherein said filling method comprises: when the pyrotechnic powder is conveyed, a step of regulating the powder flow rate wherein the powder conveyor device is set in vibration according to a vibration frequency control sequence, the vibration frequency being inversely proportional to the filling ratio of the container of the pyrotechnic charge.

2. The filling method according to claim 1, wherein the vibration frequency control sequence comprises at least: a first phase wherein the powder conveyor device is set in vibration according to a first frequency until reaching a first filling ratio of the container, then a second phase wherein the powder conveyor device is set in vibration according to a second frequency until reaching a second filling ratio of the container, the first frequency being higher than the second frequency.

3. The filling method according to claim 1, wherein the filling system comprises a selection device, the selection device including a collector vat and a lower funnel configured to enable filling of the container, said method comprising: a step of measuring the amount of pyrotechnic powder contained in the basin of the measuring device, when the amount of pyrotechnic powder contained in the basin corresponding to a desired amount of pyrotechnic powder to be introduced into the container of the pyrotechnic charge, a step of checking up the position of the selection device wherein it is checked that the basin is facing the lower funnel.

4. The filling method according to claim 3, comprising: when the amount of pyrotechnic powder contained in the basin does not correspond to the desired amount of pyrotechnic powder, a step of checking up the position of the selection device wherein it is checked that the basin is facing the collector vat.

5. The filling method according to claim 3, wherein: the filling system comprises a second lower funnel for collecting the pyrotechnic powder poured into the lower funnel hereinafter called «first lower funnel», the filling method comprising: a step of conveying the container of the pyrotechnic charge in front of the second lower funnel, a step of coupling the second lower funnel with the container of the pyrotechnic charge.

6. The filling method according to claim 1, wherein the filling system is equipotential such that an electrostatic retention of pyrotechnic powder grains is avoided.

7. The filling method according to claim 3, comprising a step of vibration setting wherein at least the first lower funnel is set in constant vibration.

8. The filling method according to claim 1, wherein the reservoir for dispensing the pyrotechnic powder is associated with two measuring devices, each measuring device being associated with a powder conveyor device for conveying pyrotechnic powder from the reservoir to a basin of the corresponding measuring device, the step of regulating the pyrotechnic powder flow rate being implemented when the pyrotechnic powder is conveyed by one of the conveyor devices and/or both the conveyor devices.

9. The filling method according to claim 8, comprising: a step of measuring the amount of pyrotechnic powder contained in each basin of the measuring devices, when the amount of the pyrotechnic powder contained in at least one basin corresponds to the desired amount of pyrotechnic powder, a step of checking up the position of the selection device wherein it is checked that the basin containing the amount of pyrotechnic powder corresponding to the desired amount of pyrotechnic powder is facing the first lower funnel.

10. A filling system for filling a container of a pyrotechnic charge, comprising at least: a reservoir for dispensing a pyrotechnic powder, a measuring device for measuring the pyrotechnic powder, and a powder conveyor device for conveying this the pyrotechnic powder from the reservoir to a basin of the measuring device, wherein the filling system comprises a vibrational actuator, coupled to the powder conveyor device for conveying the pyrotechnic powder.

11. The filling system according to claim 10, comprising a controller configured to implement a vibration frequency control sequence, the vibration frequency being inversely proportional to the filling ratio of the container of the pyrotechnic charge.

12. The filling system according to claim 10, comprising a selection device including a collector vat and a lower funnel, the selection device is configured to set the collector vat or the lower funnel in a position facing the basin.

13. The filling system according claim 12, comprising said lower hereinafter called “first lower funnel” and a second lower funnel for collecting the pyrotechnic powder poured into the first lower funnel, wherein the second lower funnel is configured to be coupled with the container of a pyrotechnic charge conveyed beforehand.

14. The filling system according to claim 10, wherein the reservoir for dispensing the pyrotechnic powder is associated with two powder measuring devices, each powder measuring device being associated with a powder conveyor device for conveying pyrotechnic powder from the reservoir to a basin of the corresponding measuring device.

15. A filling set comprising: a first filling system according to claim 10; a second filling system according to claim 10; the first filling system being configured to fill the container of the pyrotechnic charge with a first type of pyrotechnic powder and the second filling system being configured to fill the container of the pyrotechnic charge with a second type of pyrotechnic powder.

Description

[0161] Other aspects, objects and advantages of the invention will appear upon reading the following detailed description of preferred embodiment thereof provided as non-limiting examples, made with reference to the following appended drawings:

[0162] FIG. 1 schematically represents a filling system,

[0163] FIG. 2 schematically represents a side view of the filling system,

[0164] FIG. 3 illustrates a vibration frequency control sequence of the dispenser system.

[0165] In FIGS. 1 and 2, the system 1 for filling a container 2 with a pyrotechnic charge adapted to implement the method as defined in the present document is represented.

[0166] The filling system 1 is controlled using an electronic controller configured to carry out the steps of the method described in the present document.

[0167] The filling system 1 is represented mounted on a production line for mass filling of containers 2 with pyrotechnic charges.

[0168] In FIG. 1, the progress direction of such a production line is represented by a longitudinal direction L.

[0169] In FIG. 2, the progress direction is represented by a direction T orthogonal to the longitudinal direction L.

[0170] A vertical direction V orthogonal to each of the longitudinal L and orthogonal T directions is also represented.

[0171] As represented, the filling system 1 comprising at least one reservoir 10 for dispensing a pyrotechnic powder, a device 11 for measuring this powder, and a device 12 for conveying this powder from the reservoir 10 up to a basin 11a of the measuring device 11.

[0172] A vibrational actuator 12a, such as a piezoelectric actuator, is coupled to the device for conveying this powder.

[0173] The vibrational actuator 12a then generates vibrations according to a vibration frequency that could be variable.

[0174] Advantageously, the measuring device 11 is mechanically linked directly to a neutral reference frame R0, such as the ground. The mechanical dependence to such a reference frame allows ensuring that the measurement of the amount of powder contained in the basin 11a is not altered by mechanical disturbances from the elements constituting the filling system 1.

[0175] Similarly, the at least one vibrational actuator 12a is mechanically linked directly to a neutral reference frame RO, such as the ground. It is then possible to limit the propagation of these vibrations to other elements constituting the filling system 1 which could distort the measurement of the amount of powder contained in the basin.

[0176] Advantageously, the conveyor device 12 may comprise a hopper.

[0177] The measuring device 11 may be formed by a scale to which the basin 11a is fastened forming a doser, herein represented in the form of a spoon.

[0178] As represented in FIG. 2, the filling system 1 comprises two powder measuring devices 11, each powder measuring device 11 being associated to a device 12 for conveying powder from the reservoir 10 up to a basin 11a of the corresponding measuring device 11.

[0179] Advantageously, a reservoir 10 may be provided for each measuring device 11 and conveyor device 12.

[0180] Each basin 11a of the measuring devices 11 is associated to an upper funnel 13 for collecting the powder contained in the corresponding basin 11a.

[0181] A device for selecting basins 11a includes a collector vat 15 and a lower funnel 16. Advantageously, the selection device is intended to position the collector vat 15 and/or the lower funnel 16 opposite the upper funnel(s) 13.

[0182] For this purpose, the collector vat 15 and/or the lower funnel 16 of the selection device are guided in translation according to the progress direction of the production line.

[0183] The filling system comprises said lower funnel, called first lower funnel 16, and a second lower funnel 17 for collecting the powder poured into the first lower funnel 16, the second lower funnel 17 is intended to be coupled with the container 2 of the pyrotechnic charge conveyed beforehand.

[0184] An outlet opening 17a of the second lower funnel 17 is beveled to facilitate coupling thereof with an inlet opening 2a of the container 2 of the pyrotechnic charge.

[0185] The steps of the method allowing filling the container with the pyrotechnic charge described in the present document will now be described.

[0186] When the powder is conveyed, a step of regulating the powder flow rate is carried out in which each conveyor device 12 is brought to vibrate according to a vibration frequency control sequence, the vibration frequency being inversely proportional to the filling ratio of the container 2 of the pyrotechnic charge.

[0187] FIG. 3 illustrates such a vibration frequency control sequence represented by the filling ratio Tr in percentage proportional to the filling time.

[0188] The vibration frequency control sequence comprises a first phase 100 in which the conveyor device 12 is brought to vibrate according to a first frequency F1 comprised between 16 Hz and 18 Hz, preferably 17 Hz, until reaching a first content ratio of the container comprised between 50% and 80%, preferably at least equal to 75%, of the desired filling ratio of the container, then a second phase 200 in which the conveyor device 12 is brought to vibrate according to a second frequency F2 comprised between 13 Hz, and 16 Hz, preferably 15 Hz, until reaching a second filling ratio of the container comprised between 80% and 95%, preferably at least equal to 90%, of the desired filling ratio of the container.

[0189] In this example, the vibration frequency control sequence comprises a second similar phase 200′ in which the conveyor device is brought to vibrate according to a second similar frequency F2′ preferably comprised between 8 Hz and 13 Hz, preferably 10 Hz, said second similar frequency F2′ being lower than said second frequency F2.

[0190] The vibration frequency control sequence then comprises a third phase 300 in which the vibration of the conveyor device 12 is stopped until stabilisation of the measured amount of powder, for example over a time period substantially equal to 2000 ms.

[0191] Following this third phase, if the measured amount of powder corresponds to the desired amount of powder, the vibration frequency control sequence is terminated and the basin is considered to be properly dosed and the method could be carried on until filling of the container with this powder dose.

[0192] If the measured amount of powder is larger than the desired amount of powder, the vibration frequency control sequence is terminated, the basin is considered to be wrongly dosed and the method could be carried on until discarding or recovering this powder dose.

[0193] Following the third phase 300, if the measured amount of powder is smaller than the desired amount of powder, for example when the filling ratio is comprised between 95 and 98%, a fourth phase 40 could be carried out, in which the conveyor device 12 could advantageously be brought to vibrate according to a third frequency F3 comprised between 10 Hz and 20 Hz, and more preferably equal to 14 Hz, over a predetermined time period, for example equal to 1000 ms, then a new stabilisation phase, herein a fifth phase, similar to the third phase.

[0194] Following this fifth phase, if the measured amount of powder corresponds to the desired amount of powder, the vibration frequency control sequence is terminated and the basin is considered to be properly dosed and the method could be carried on until filling the container with this powder dose.

[0195] Of the measured amount of powder is smaller than the desired amount of powder, for example when the filling ratio is comprised between 95 and 98%, the fourth and fifth phases could be repeated until reaching the desired amount of powder.

[0196] If the measured amount of powder is larger than the desired amount of powder, the vibration frequency control sequence is terminated, the basin is considered to be properly dosed and the method could be carried on until discarding or recovering this powder dose.

[0197] Moreover, it is possible to carry out an initial phase where the conveyor device 12 is brought to vibrate according to a start-up frequency FD over a predetermined start-up time period, for example equal to 190 ms, prior to the first phase 100, that being so to allow reaching the desired filling ratio more rapidly.

[0198] For example, the start-up frequency FD is higher than 18 Hz. For example, the start-up frequency FD is comprised between 18 Hz and 20 Hz. For example, the start-up frequency FD is substantially equal to 19 Hz.

[0199] The first frequency is called «very high speed frequency», the second frequency is called «high speed frequency», the second similar frequency is called «low speed frequency» and the third frequency and the start-up frequency are called «boost frequencies».

[0200] Starting from the third phase 300, the powder grains are conveyed into the continuous basin by pouring following the last vibration phase. In this third phase 300, the measurement of the amount of powder contained in the basin settles down over time.

[0201] Concurrently with the step of regulating the powder flow rate, a step of measuring the powder contained in each basin 11a of the measuring devices 11 is carried out.

[0202] When the measurement of the contained powder in at least one basin 11a is equal to a predetermined value corresponding to the desired amount of powder to fill the container 2 with the pyrotechnic charge, a step of checking up the position of the selection device is carried out in which it is checked that the upper funnel 13 associated to said basin 11a containing said predetermined value is disposed opposite the lower funnel 17.

[0203] When at least one basin 11a or each basin 11a is properly dosed, any one of these basins 11a is retained to pour the powder contained therein into the container 2 of the pyrotechnic charge.

[0204] When the measurement of the powder contained in at least one basin 11a is not equal to the predetermined value, a step of checking up the position of the selection device is carried out in which it is checked that the upper funnel 13 associated to said basin 11a that does not contain said predetermined value is disposed opposite the collector vat 15.

[0205] When the collector vat 15 is not opposite the upper funnel 13, the selection device is displaced to achieve this position setting.

[0206] The wrongly dosed content of the basin 11a is then received without interrupting the production line.

[0207] When the content of the basin 11 a is properly dosed, a step of checking up the position of the selection device is carried out in which it is checked that the upper funnel 13 associated to said properly dosed basin 11a is disposed opposite the first lower funnel 16.

[0208] When the first lower funnel 16 is not opposite the upper funnel 13, the selection device is displaced to achieve this position setting.

[0209] Then, a step of conveying the container 2 of the pyrotechnic charge opposite the second lower funnel 17 is carried out, then a step of coupling the second lower funnel 17 with the container 2 of the pyrotechnic charge.

[0210] It should be understood that a properly dosed basin 11a corresponds to the basin 11a where the measurement of the powder contained therein is equal to a predetermined value corresponding to the desired amount of powder.

[0211] In the coupling step, the second lower funnel 17 is displaced vertically to achieve this coupling.

[0212] Then, the powder content of the basin is poured into the corresponding upper funnel 13 and it is conveyed by gravity up to the container of the pyrotechnic charge conveyed beforehand. Herein, the basin is formed by a spoon whose stem is configured to be rotated to pour its content. To this end, the measuring device may comprise a motor provided to this end.

[0213] Of course, the funnels by which the powder is conveyed are disposed successively next to one another to enable this transfer.

[0214] The funnels may be brought to vibrate to facilitate this transfer and avoid any powder accumulation phenomena during this transfer.

[0215] It is also possible to provide for making the funnels equipotential to avoid all electrostatic phenomena.

[0216] Of course, the invention is not limited to the examples that have just been described and many arrangements could be brought to these examples yet without departing from the scope of the invention. In particular, the different features, shapes, variants and embodiments of the invention could be associated with one another according to various combinations to the extent that these are not incompatible or do not exclude each other. In particular, all of the previously described variants and embodiments could be combined together.