Electric heating – Heating devices – With power supply and voltage or current regulation or...
Patent
1994-11-23
1997-04-15
Paschall, Mark H.
Electric heating
Heating devices
With power supply and voltage or current regulation or...
219535, 219506, 219497, 1563042, 1563797, H05B 102
Patent
active
056206259
DESCRIPTION:
BRIEF SUMMARY
The invention relates to the field of using butt-welding for connecting parts made from a plastics material and in particular parts made from polyethylene.
Butt-welding is a known technique which is carried out by bringing into contact two oppositely facing ends of two parts which are to be joined, the abutting ends in question of the parts being previously heated to their softening or fusion temperature so that their contact under pressure ensures a satisfactory weld once they have cooled.
Although machines are currently available which make it possible in particular to heat up the abutting ends of the parts, it is on the other hand currently left to the discretion and competence of the operators to establish in particular the dimensional and qualitative compatibilities of the parts to be assembled and to adapt the welding criteria to be respected.
In practice, the outcome is a certain number of errors prejudicial to the reliability of the networks and pipes, the quality of the welds depending on the competence of the operators and the conditions under which they intervene.
Well, for the ever-increasing number of applications and in particular for establishing networks for the distribution of a fluid (gas, air or other industrial liquids), it is found that increasingly more frequent use is made of tubes of plastics material which, in a number of cases, have to be butt-welded under heat in the manner described briefly hereinabove.
Furthermore, there are various standards or criteria for welding and the manufacturers or users of parts have to comply with them, which further increases the risks of errors in interpretation.
SUMMARY OF INVENTION
The object of the invention is to provide a solution which makes it possible markedly to reduce these risks, ensuring a security of procedure and reliability of the welds whatever the working conditions may be in practice.
To this end, the invention proposes a method of selectively butt-welding two tubular parts of plastics material using an automatically controlled machine, in which process: the machine is associated with each of the parts, entered in an order and at specific positions for each code: end where it has to be welded substantially coaxially to the other part, an electric heating element has to be raised for the abutment end of the said part to reach the softening temperature appropriate for welding, contact with the heating element, against the other part, part must undergo during the said period of time according to b.sub.4, characteristics b.sub.1) to b.sub.7) of the two codes are in accord in pairs, at least in some cases, a compatibility between codes is recognised and a series of values common to the two parts is determined relatively and respectively at least: abutting ends of the parts to reach their the softening temperature appropriate to welding them, with this heating element, the one against the other, and between the parts, associated with the machine in order to allow welding of the parts as a function at least of the said values determined according to e).
In this way, the parts may be joined with virtually no risk of error as to their compatibility and the essential parameters of welding to be respected.
In practice, the "concordances" to which reference is made in stage e) may be strict (identity between the values corresponding to the characteristics relative to each code) or "relative" (compatibility recognised when the values match in certain predetermined ranges of tolerances, or if the ranges of attributed values overlap.
On the hypothesis that such a "relative" compatibility will be acknowledged, then the series of aforesaid values (T, P, t.sub.1, t.sub.2) needed to determine the welding conditions may in particular be obtained mechanically by machine, using an integrated computer unit of calculation providing a mean value for each parameter T, P, t.sub.1, t.sub.2 on the basis of values subject to tolerances or ranges of concordant values scanned over the codes.
Within the framework of the welding operations taken as a whole, a f
REFERENCES:
patent: 4323773 (1982-04-01), Carpenter
patent: 4642155 (1987-02-01), Ramsey
patent: 5013376 (1991-05-01), McElroy, II et al.
patent: 5130518 (1992-07-01), Merle
Kunstof and Rubber 1990, #10 by Meijerink et al pp. 59-61.
Hugueny J. C.
Sauron Jean
Gaz de France (Service National)
Paschall Mark H.
Ste. Joseph Sauron Materiel Industriel, (S.A.)
LandOfFree
Method of butt-welding two plastic parts with an identifying cod does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of butt-welding two plastic parts with an identifying cod, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of butt-welding two plastic parts with an identifying cod will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-358334