1、Which is better, hot melt fittings or electrofusion fittings?
Both have their own advantages, but in European countries electrofusion fittings are generally used in emergency repair or can not be placed when the hot melt welding machine. International requirements for hot melt butt welding, two pipe diameter alignment deviation can not exceed 10% of the diameter, so small diameter (Dn ≤ D90) is difficult to grasp, in addition to the large-caliber electrofusion fittings are too expensive caused by the current market, small-diameter electrofusion connections, large-caliber connections with hot melt.
2, electrofusion pipe fittings observation holes after welding how to adjust the length of the emergence, how long is good?
In the case of a certain wall thickness of fittings can be adjusted by the depth of the deployment of electric anode wire, the length of the emergence of the observation hole can also be a side reflection of the good and bad wiring, emergence is too long to indicate that the wiring is too deep, too short to indicate that the wiring is too shallow. General observation hole emergence only as a sign of completion of welding, no specific requirements, but the normal emergence of 5mm ~ 6mm is appropriate.
3, electrofusion pipe fittings welding short circuit, boiling caused by what, how to prevent?
The most frequent cause is the tube in the pipe fittings positioning is not correct; insertion depth is not in place, the axial direction is not centered; or pipe and fittings size with a large deviation, such as the pipe’s out-of-roundness seriously exceeds the standard. In addition may also be due to electrofusion fittings and pipe connection with moisture or heating time is too long to make the electric anode wire in the pipe fittings inside the tour of the two contact, or the use of bare wiring fittings when the electric anode wire is oxidized or inserted when the resistance wire out of the electric anode wire selection is not appropriate, transient heating caused by the local carbonization also caused by the short-circuit. Should be cleaned before welding fittings and pipe surface debris, scrape off the surface of the pipe oxide layer, the use of embedded wiring fittings, in strict accordance with the process of welding.
4, pipe and pipe with different wall thickness (or fittings) can direct hot melt butt?
Pipe and pipe with different wall thickness (or fittings) if direct hot melt butt joints, due to the heating temperature of the hot plate is the sametemperature, and pipe and pipe (or fittings) hot melt area of the cross-sectional area of the pipe (or fittings) is not the same, and the same fusion pressure exerted, which will lead to inconsistent weld crimp, can not guarantee the adhesive effect between the two, affecting the quality of butt joints.
5, different grades of polyethylene raw materials produced by the pipe, pipe fittings can be connected?
Different grades of polyethylene raw materials produced by the pipe, pipe fittings, if connected, the joints should be hydraulic test. Generally speaking, melt flow rate (MFR) (190’C/5kg) in 0.2a/10min between PE63, PE80, PE100 mixture should be regarded as with the melting, each other can be connected to each other, outside this range of raw materials need to talk about the line of tests to determine. At present, it is usually thought that: electrofusion connection, electrofusion fittings and pipe connected to it can be different material grade: but hot melt butt to the same level of material connection between the standardized practice.
