The PPH tube is made of high-density polypropylene (PPH) with equivalent antioxidants, UV-resistant agents and pigments. PPH tube has good heat setting, high temperature resistance, good chemical resistance, creep, tension, good insulation, insolubility in organic solvents, no cracking, no toxicity and other characteristics. Suitable for a variety of industries such as chemical plants, electronic semiconductor plants, pharmaceutical plants, sewage treatment plants. It has been widely used in high acid and alkali chemical product conveying systems, pure water conveying systems, drinking water transportation systems, sewage drainage systems, environmental engineering and general piping systems, and telecommunication cable transmission and distribution piping systems.
First, the characteristics of PPH pipe
1, long service life - under the rated temperature and pressure conditions, can be safely used for more than 50 years.
2, excellent corrosion resistance - this product can withstand a wide range of high acid and alkali corrosion with a pH range of 1-14.
3, heat-resistant insulation and energy-saving - the product has a small thermal conductivity and has a good thermal insulation performance.
4. Reliable connection performance--The strength of the hot melt interface of this product is higher than that of the pipe body, and the joint will not be broken due to soil movement or load.
5, good construction performance - the product is light in weight, simple welding process, convenient construction, low comprehensive engineering cost, can meet complex process pipelines.
Second, the scope of application of PPH pipe:
It is suitable for conveying various concentrations of sulfuric acid, hydrochloric acid and various organic acids, strong acids and strong oxidants from -20 °C to 90 °C. It is also suitable for various concentrations of strong alkalis, organic solvents and other corrosive gases and liquids. The conduit for the media.
Third, PPH pipe welding method
1, welding equipment
The welding of PPH pipes is hot-melt welding, and various types of hydraulic or manual plastic pipe heat welding machines are used. Taking a hydraulic plastic pipe heat-sealing machine as an example, the welding is mainly divided into three parts: a welding machine control platform, a welding operation platform, and a tool placement frame.
2, welding preparation
The pipe cutter (tube cutter), acetone, and clean cloth of the matching pipe type are kept clean and dust-free, and the ambient temperature is maintained, and should not be lower than 0 °C.
3, hot melt welding
The welding is mainly divided into 7 steps of feeding, preheating, countering, heating, welding, cooling and inspection.
a, cutting
Cut the pipe to the required size with a special cutter. When cutting the pipe, be careful not to run the line and slowly screw into the blade. Do not over-jerk and damage the blade. When the cutter is difficult to rotate, the cutter should be rotated in the opposite direction, the blade should be taken out, and the line should be re-run.
b, preheating
The preheating pressure is adjusted to the welding required pressure using a PPH pipe hydraulic regulating valve. Adjustment method: lock the heating pressure relief valve, the hydraulic operating rod advances, and the pressure gauge displays the pressure. When the required pressure is not reached, loosen the heated pressure relief valve to reduce the pressure gauge display to zero, re-adjust the hydraulic pressure regulating valve, and then lock the heated pressure relief valve until the pressure is expressed to the required pressure.
The temperature setting panel on the welding machine control platform is used to set the temperature of the hot melt welding, and the temperature of the heating plate is controlled to match the welding surface melting. Red shows the set temperature and green shows the current temperature. When the red light on the panel jumps to the green light, hot-melt welding can be performed. The PPH hot melt temperature is generally set between 195 ° C and 205 ° C.
c, counterpart
1 Select the appropriate mold and fix the welded pipe section to the operating platform with a wrench;
Note: When fixing, tighten the fastening screws at both ends of the clamp one by one to avoid the pipe section not leveling; when the two pipe sections are retracted to the maximum after the hydraulic operating lever is retracted, the distance should not be less than the thickness of the electric cutting machine; the welding surface of each pipe section should be protruding When the 40~50mm pipe section is long, pay attention to the overall level.
2 The hydraulic lever is pushed to the maximum and the two pipe sections are matched. Visually measure the misalignment of the weld surface, and touch the hand on the lower half to make the two seams horizontal. When the requirements are not met, the screws are adjusted by adjusting the two ends to make the weld seam have no wrong mouth and reach the level;
3 Visually inspect the joints of the two weld faces, to achieve no obvious gaps in the joints; if any, use an electric cutter to grind the joints. Place the cutting machine on the operating frame, start the cutting machine, and then the hydraulic propulsion rod is operated by another person, and the pipe section is pressed against the cutting machine with the set pressure; the welding surface is visually cut until the welding surface is flush. Retract the hydraulic clamp, take out the cutting machine, and put it back into the tool placement frame;
Note: After retreating the hydraulic clamp, do not rush to stop the cutting machine and let the cutting machine turn a few turns before removing it. It can make the welding surface smoother and prevent the cross section.
4 Clean the soldering surface and clean the soldering surface with a small amount of acetone.
d, heating
Remove the hot plate that has reached the required temperature from the PPH pipe tool placement rack. Place it on the operating frame and push the hydraulic clamp on one side of the welding surface to bring the pressure to the required welding pressure. When the hot melt flange of the welding surface reaches 1mm, the heating pressure relief valve is released, the heating pressure is removed, and after waiting for a certain period of time, the hot melt butt joint of the welding surface is met.
Note: The heating plate must be placed vertically.
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