In a twinkling of an eye, it has entered October and will soon enter winter.
The cold in winter frequently brings a variety of difficulties to the construction. After the pipeline buried project enters the winter construction state, it is also necessary to carry out the construction in accordance with the winter construction technical regulations.
The welding work of PE pipe is the key control link in pipeline burying engineering.
In winter nature has become a top priority, we and China HDPE parts factory to understand:
1. Increase the preheating temperature before welding
In order to slow down the heat loss due to low temperature environment, the preheating range of PE pipe is increased from 75mm on both sides of the groove as required by the specification to 120mm on both sides of the groove, and the preheating temperature is 100-120℃. The temperature is measured by a digital display infrared thermometer, and measured at 100mm-120mm away from the diameter of the pipe. 8 points on the uniform circumference should be measured. The root weld should be welded immediately after the preheating.
2. Ensure the temperature between layers
Specification requirements: temperature between electrodes ≥80℃; other interlayer temperature of welding passage ≥60℃; in order to ensure the temperature between layers, each layer of pass welding must be compact, after the completion of the previous process, immediately proceed to the next process. 8 points on the uniform circumference of each layer should be measured before welding.
When the inter-layer temperature is lower than the specification requirements, the flame heater is used for re-preheating, and the inter-layer temperature of the cellulose electrode is not less than 80℃, and the inter-layer temperature of other welding passages is not less than 60℃. Increase the collection of preheating and interlayer temperature. The interlayer temperature of each welding joint preheating and each layer of welding passage before welding must be measured and recorded.
3, PE pipe after welding insulation
When the ambient temperature is lower than 5℃, the insulation cover should be affixed to the weld passage after welding to prevent sudden cooling of the weld passage. The insulation cover is an asbestos cover. The specific practice is: use a blowtorch to bake the asbestos to more than 80℃, and then immediately complete the welding joint while it is hot and covered with felt, with a rubber belt tied tightly. The insulation time should be at least half an hour.
PE pipe welding construction in winter should be carried out in accordance with the above procedures, so as to ensure the welding quality, at the same time should be reasonable arrangement of welding time, should try to arrange the welding time in the daily temperature is higher than -5 degrees Celsius, when the ambient temperature is lower than -5 degrees Celsius, the welding quality will be difficult to ensure, the need to stop the welding work.