Process and apparatus for evaluating the degree of vacuum in closed bodies with transparent walls
View Patent ↗The invention is based on feeding the closed bodies to be evaluated to a station for the application of high voltage for the formation of the arc across the inner space of the body and capturing the arc formed by means of a CCD camera which will compare, adjustably, the luminous intensity of the arc created within the body subjected to checking with a threshold value determining whether the luminous intensity is above or below the threshold, which will be the rejection threshold, rejecting the bodies which do not comply with the predetermined threshold value, separating them from the whole of the accepted bodies.
1. A process for evaluating the degree of vacuum in closed bodies with transparent walls, by means of formation of an arc across each closed body by the application of an electrical field, said process comprising the following consecutive operating stages:
feeding the bodies to be inspected in succession;
transferring the bodies to means bearing an earth electrode;
moving the bodies along a path determined by the means carrying the earth electrode in contact with same;
application of one or more pre-ionisation charges at one or more points on the transport path;
application of one or more checking electrodes applying one or more high voltage charges in order to produce the electric arc across each body between said electrodes and the earth electrode or electrodes;
inspecting the arc or arcs formed inside said body by means of respective artificial vision cameras;
subjecting the reading taken by the artificial vision cameras to an algorithm for evaluation of the arc;
referencing the bodies according to the result of the arc evaluation for their selection;
generating signals for differentiated exit of the bodies.
2. A process according to claim 1 , wherein the algorithm for evaluation of the arc permits the selection of the bodies by a threshold value of the degree of vacuum above which the product will be accepted.
3. A process according to claim 1 , wherein the algorithm for evaluation of the arc permits the classification of the bodies by level within a range with predetermined maximum and minimum of the vacuum level.
4. A process according to claim 1 , wherein the algorithm for evaluation of the arc makes it possible to effect the selection of the bodies by chromatic identification.
5. A process according to claim 1 , wherein the algorithm for evaluation of the arc permits the classification of the bodies by the form of the luminosity generated by the arc.
6. A process according to claim 1 , wherein the algorithm for evaluation of the arc permits the classification of the bodies by comparison with a master image regarded as acceptable.
7. A process according to claim 4 , wherein chromatic identification is effected by the distribution and values of the colours red, green and blue of the image captured by the vision camera.
8. A process according to claim 1 , wherein the differentiated exit of the bodies takes place by separating the accepted bodies towards one outlet or several outlets and the unaccepted bodies to one outlet or several outlets.
9. A process according to claim 1 , wherein the differentiated exit of the bodies takes place according to the estimated value of the level of vacuum therein.
10. An apparatus for evaluating the degree of vacuum in closed bodies with transparent walls, by the application of a high potential across the closed body, wherein it comprises means for guiding and transporting the bodies along a fixed path at a predetermined speed, the path comprising a first, pre-ionisation station and an earth electrode parallel to the path of movement and transport and in contact with the bodies during their transportation, the apparatus then having means for active checking intended for the application of a high voltage for the arc formation and the apparatus having an artificial vision camera arranged for the observation of the arc formed inside the body and having means for the application of an algorithm for evaluation of the arc formed in the body and the apparatus also having exit stations for rejected and accepted bodies.
11. An apparatus according to claim 10 , wherein the means for guiding and transporting the bodies comprise a circular revolving plate arranged on a support table with the interposition of an interchangeable insulating panel, which plate bears pick-up seats for the individual bodies and an earth electrode which is capable of being contacted by each of the bodies as they move along the fixed path.
12. An apparatus according to claim 10 , wherein the pre-ionisation station comprises one or more high voltage electrodes for the pre-ionisation of the bodies.
13. An apparatus according to claim 10 , wherein the means for guiding and transporting the bodies comprise two revolving plates arranged in tandem with individual or common feeds and outlets for each plate.
14. An apparatus according to claim 10 , wherein the active checking means for the application of voltage for forming the arc are constituted by one or more electrodes capable of generating a high voltage between the actual electrode and the earth electrode on which the body is in contact in order to permit the formation of the arc.
15. An apparatus according to claim 10 , whereby arrangement of an enclosure for protection against the external luminosity and anti-reflective for the artificial vision camera.
16. An apparatus according to claim 10 , whereby arrangement of the whole of the analysis apparatus within a light-absorbing enclosure, intended to absorb reflections in the stages of energising and measurement of the arc in the bodies.