The most widely used types of medium and high voltage wire spare parts are heat shrinkable sleeve wire spare parts, prefabricated wire spare parts and cold shrinkable wire spare parts. They have secondary characteristics:
1. Heat shrinkable wire spare parts
The blends of polyethylene, ethylene-ethylene acetate (EVA) and ethylene-propylene rubber were used normally. Secondly, stress tube is adopted to solve the problem of electric stress aggregation. That is to say, the parameter control method is adopted to alleviate the stress set of magnetic field.
Secondary advantages: bulky, simple device, good function, low price.
Stress tube is a kind of thermal expansion tube with moderate volume resistivity (10 ^ 10 - 10 ^ 12_/cm) and high dielectric constant (20 - 25). Electrical parameters are applied to force the stress at the break of wire insulation barrier to disperse into a more symmetrical distribution along the stress tube. This skill can only be used in 35kV and secondary wiring spare parts. Because the stress tube will be feverish when the voltage title is high, there is no reliable task.
In its application, the technical achievement of heat shrinkage pipe damage is that to ensure the electrical parameters of stress tube, it is necessary to reach the values of the above-mentioned norms in order to be able to work reliably. In addition, attention should be paid to filling the air gap from the fracture of the semi-conductive layer of gas wire insulation with silicone grease to clean up the gas, so as to achieve the means of reducing all the tip discharges.
Cross-linked wires will expand considerably when they are in operation due to the lack of internal stress solution. Therefore, when installing spare parts, it should be noted that the cover of stress tube and insulation barrier is not less than 20 mm, in order to prevent the stress tube from breaking away from the insulation barrier when expanding.
Because of the small inertia of heat shrinkable wire spare parts, it can make the interfacial dynamic gap when heat expands and cold shrinks in operation, so the sealing skill is very important to prevent water immersion.
2. Prefabricated Wire Spare Parts
The data used are normally silicone rubber or ethylene propylene rubber.
Secondly, how many structural methods are adopted, i. e. stress cones, to solve the problem of stress aggregation.
Secondly, it has the following advantages: high-quality data function, more complicated and fast device, no heating can be installed, good inertia, making the interface function lose a greater improvement.
In the process of brushing double-wall heat shrinkable tube with liquid flexible packaging film printing, attention should be paid to the selection of suitable materials. In the actual production, we should choose the suitable printing and packaging film and printing ink according to the filling progress, sterilization premise and product shelf life of the automatic filling machine, and adjust and control the printing process parameters according to the actual situation, standardize the process flow and guarantee the printing quality of the film. Polyamide printing ink has poor water resistance and grease resistance, and liquid-wrapped ink can not be chosen repeatedly. Polyurethane ink has the same type and should be selected with alignment. New Western Chaolifu 313A ink is generally only used for soft co-extrusion PE film, while 314 ink is used for all kinds of co-extrusion PE heat-shrinkable sleeves. The co-extruded PE film used by color printing factories is usually blown by the factories themselves, and the technological level is different. Therefore, the selection of masterbatch should be controlled well, and masterbatch without smoothing agent should be used. After the selected PE film is processed by soldering, the inner energy can reach 40 dynes at least, preferably more than 42 dynes.
Presupposition or test criteria for post-processing of depositors. Only when the high temperature heat shrinkable tube is fully inspected by the food manufacturer when filling and the current processing technology, and even the bottom details of the obscure links of liquid package in the market, can the color printing manufacturer achieve no target, which is rare in mind. The first points of attention include filling progress, sterilization premise, shelf life, preservation and so on.
Printing process requirements. In order to guarantee the printing quality of liquid packaging film, we must also pay attention to the control of printing tension, printing pressure, printing progress and monotonous heat in the printing process, create a set of invariable and reliable process standards, standardize the process flow, and ensure the smooth continuation of planned products. In addition, the comprehensive nature of the printing workers, the technical information provided by the ink manufacturers, the quality of the thin materials in black and white, and the change of the status of the group are also factors that can not be ignored.
Control the printing situation. The change of temperature and humidity in the printing group has no need to protect the performance of the material and ink. Too monotonous condition will cause the film static electricity and make the printing hard. Too humid condition will make the ink monotonous and insufficient, so there is no need for the solid degree of the ink layer.