Electric heating – Metal heating – By arc
Patent
1987-04-20
1989-08-08
Shaw, Clifford C.
Electric heating
Metal heating
By arc
219 75, B23K 906
Patent
active
048555665
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
The invention relates to the striking of an electric welding or cutting arc with an electrode and in particular a refractory electrode, of the type comprising producing, between a refractory electrode and either an auxiliary electrode adjacent to said refractory electrode, or a part to be welded or cut, an ionizing discharge of high-voltage electric pulses forming at least one spark from a pulse generator.
Conventionally, the high-voltage electric pulse discharge is produced by means of a high-frequency generator which is of necessity, owing to its weight and overall size, disposed at a distance from the welding torch and is generally more or less integrated with the welding current generator. Such a manner of creating in the region of the refractory electrode a high-frequency electric discharge presents notable drawbacks as concerns the very high cost of the high-frequency generator and the adverse effects on the environment caused by these discharges which produce radio-electric disturbances, in particular as concerns,. telecommunications. and electronic equipment such as encountered in plant automation. Moreover, the effectiveness of the high-frequency discharge is very dependent on the distance between the generator and the torch so that the high-frequency generator must be over-dimensioned in order to take into account the sometimes relatively large distances between the welding station and the welding generator, which still further increases the aforementioned drawbacks.
The use has indeed been proposed of small pulse generators of the electronic ignition type having a capacitive electric charge dischargeable into a step up voltage transformer. In respect of the known proposal, the generator is simply connected between the part to be welded and an auxiliary electrode, and experience has shown that this manner of proceeding does not ignite the arc with certainty.
The present invention provides an arc striking process which avoids any radioelectric disturbance owing to the possibility of considerably reducing the distance between the torch and the generator and therefore the level of the power of the generated pulses; moreover, the cost of the equipment is considerably reduced while ensuring a satisfactory ignition of the arc. According to the invention, the following measures are combined: dischargeable into a step-up voltage transformer is arranged in such manner that the energy delivered by a spark is on the order of 10 millijoules; ignitor; is less than a distance on the order of eight metres and preferably on the order of four metres.
According to a preferred form of the invention, the distance between said spark gap and said refractory electrode is less than 0.5 meter, the spark gap being preferably disposed in the region of, or in, the torch body.
By electronic ignitor is meant small spark or sparktrain generators incorporating at least one electric capacitor with its charging and discharging means with rise in voltage which are common on the market and in respect of which none of the three dimensions generally exceeds 10 cm and the weight is relatively light, on the order of 100 g to 200 g while the power of a spark is on the order of 10 millijoules. An ignitor of this type is sold by the French firm RV under the commercial name REF 177 "1 or 2 Point Electronic Ignitor." It is one of the merits of the present invention to have noticed that such a small and light generator could be easily added without difficulty in the vicinity of the body of the torch proper, or in the bunch of cables and conduits with which this torch is equipped and whose length generally does not exceed 8 metres. Thus, the fact of being able to place the spark generator on a "mobile" part of the welding equipment and not, as before, in respect of H.F. generators necessarily grounded and more or less integral with the welding generator, permits a substantial reduction in the length of the electric discharge path, which makes it possible to use such ignitors having a very limited power per spark. It has also been
REFERENCES:
patent: 2612582 (1952-09-01), Appleton
patent: 3008036 (1961-11-01), Greene et al.
patent: 4119829 (1978-10-01), Bakardjiev et al.
English translation of French Patent No. 2,052,152 (of record).
Delzenne Michel
Gaillard Pierre
Hays Jean-Francois
Legrand Pierre
Reynaud Bernard
L'Air Liquide
Robinson, Jr. Lee C.
Shaw Clifford C.
LandOfFree
Process for striking an arc in electric welding and welding torc does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for striking an arc in electric welding and welding torc, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for striking an arc in electric welding and welding torc will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-907609