A series of application details of plastic-coated steel pipes for water supply

Plastic-coated steel pipes for water supply are made of epoxy resin or polyethylene powder on the inside and outside of the base pipe. It not only has the characteristics of high strength, easy connection, and water flow impact resistance of steel pipes, but also overcomes the defects of galvanized pipes due to easy rust, yellow water, and scale accumulation, resulting in small pipe openings and blockage, preventing secondary pollution and significantly improving water quality. Its common colors are gray, blue, and green. The unit is calculated by meter or root, and the specifications are DN15-600. The coating surface is smooth, and uniform, without dark bubbles, pits, wrinkles, or cracks. The normal pressure is 0.1Mpa-2.5Mpa, and the coating material is polyethylene or epoxy resin.

First, the characteristics of plastic-coated steel pipes for water supply

(1) Strong corrosion resistance: The plastic coating on the inner and outer surfaces can isolate the metal pipe body from the external environment, effectively preventing corrosion and rust, and can maintain good performance in harsh environments such as humidity, acid, and alkali. Whether buried in acidic soil or exposed to chlorine-containing tap water for a long time, the plastic anti-corrosion layer can effectively isolate the steel pipe from the corrosive medium and extend the service life of the pipe.

(2) Good wear resistance: The outer plastic coating has a high hardness and can withstand large friction. The surface wear is not obvious after long-term use.

(3) Low fluid resistance: The inner wall is smooth and the friction coefficient is low, which can reduce the resistance of the fluid flowing in the pipe, reduce the transportation cost, and improve the transportation efficiency. The inner wall of the plastic-coated steel pipe is as smooth as a mirror with minimal roughness. The water flows unimpeded in it and is not easy to form scale.

(4) Good insulation performance: The plastic layer has good electrical insulation, which can prevent current leakage and prevent electrical corrosion. It can be used as a wire protection tube to ensure safe electricity use.

(5) Environmentally friendly and pollution-free: It is made of environmentally friendly plastic materials, which are non-toxic and odorless. The production process also meets environmental protection requirements and will not pollute the water source for transportation, meeting the drinking water hygiene standards.

(6) Easy installation: It is relatively light in weight and has various connection methods, such as thread, groove, flange, welding, etc., which makes installation and maintenance relatively convenient. It has a certain flexibility and strong adaptability during installation. It can be bent and stretched according to the site conditions. It is not easy to break and is suitable for complex pipeline layouts and installation at bends.

(7) Long service life: Under normal use conditions, the service life of water supply plastic-coated steel pipe is relatively long, which reduces the frequency of pipeline replacement and maintenance and reduces the overall cost. The design life can reach 50 years.

Second, the application field of water supply plastic coated steel pipe

(1) Urban water supply system: It is widely used in urban tap water supply system, which can stably and reliably transport a large amount of clean drinking water and is the preferred material in municipal engineering.

(2) Industrial water system: Due to its corrosion resistance and high strength, it is widely used in industrial water delivery systems, such as chemical, electric power, metallurgy, food, pharmaceutical and other industries, and can be used to transport various corrosive or non-corrosive industrial water.

(3) Building water supply system: used in the building's water supply and drainage system, it can prevent the pipes from rusting and scaling, ensure water quality safety, and can also be used in fire protection systems, HVAC systems, etc. When used as a water supply pipe in high-rise buildings, it can effectively resist external pressure and impact.

(4) Rural drinking water safety project: provides safe and reliable drinking water for rural residents. Its good environmental performance and corrosion resistance ensure the quality and stability of rural water supply.

(5) Other fields: It can also be used on some special occasions with high water quality requirements, such as pure water transportation, laboratory water pipes, etc.; in some places that require temporary water supply, such as construction sites, temporary activity venues, etc., it can also play its advantage of convenient installation.

Third, the connection method of water supply plastic coated steel pipe

(1) Threaded connection: suitable for pipes with smaller diameters. The pipes and pipe fittings are connected together through threads. The operation is relatively simple, but the connection strength is relatively low. It is suitable for systems with low pressure. Pay attention to the processing quality and tightening torque of the threads during installation to ensure that the connection is tight and leak-proof.

(2) Groove connection: Use special grooved pipe fittings and clamps to connect the pipes. This connection method is fast to install, easy to disassemble and repair, and has good sealing performance. It is suitable for pipes with larger diameters and projects with high installation speed requirements. During installation, the processing accuracy of the groove and the quality of the pipe fittings must be ensured, and the clamps must be tightened in place.

(3) Flange connection: Weld or thread the flanges at both ends of the pipe, and then connect the two flanges together with bolts, and add a gasket in the middle to ensure sealing. Flange connection is suitable for parts that need to be frequently disassembled and repaired, as well as pipeline systems with larger diameters and higher pressures. During installation, ensure the parallelism and concentricity of the flanges, and tighten the bolts evenly.

(4) Welding (bimetallic connection): For special fields that require direct welding, bimetallic connection can be used, that is, the plastic-coated steel pipe is connected to other metal pipes or equipment through a special welding process. This connection method has high strength but has strict requirements for the welding process, and the welding process may cause certain damage to the plastic coating layer, which needs to be repaired after welding. Generally, the manufacturer needs to provide technical guidance and professional welders are required to operate.

Fourth, the production process of plastic-coated steel pipes for water supply

(1) Steel pipe pretreatment: Arrange the steel pipes neatly on the loading rack and transport them to the drying tunnel through the sprocket for preheating. The preheating temperature is 300℃ and the time is 15 minutes. The purpose is to remove impurities such as oil and rust on the surface of the steel pipe and improve the adhesion between the coating and the steel pipe.

(2) Plastic coating molding: Transfer it to the upper plastic port for molding again. Use spraying, rolling, or dipping to evenly cover the plastic powder on the inner and outer walls of the steel pipe. Common coating materials such as polyethylene (PE) and epoxy resin (EP) meet the drinking water hygiene standards and are non-toxic and harmless.

(3) Curing treatment: Curing the plastic-coated steel pipe to form a strong chemical bond between the plastic and steel pipe molecules, and achieve deep fusion of the coating and the steel pipe. Generally, the material can be unloaded after natural cooling, and the finished product inspection is carried out again to ensure that the quality and performance of the coating meet the requirements, and finally packaged and stacked.

Fifth, the key points of selecting plastic-coated steel pipes for water supply

(1) Select specifications according to project requirements: According to the design flow, pressure requirements, and transportation distance of the water supply system, select plastic-coated steel pipes with appropriate inner diameter, wall thickness, and length. Generally speaking, the larger the pipe diameter, the stronger the water delivery capacity, but the cost will also increase accordingly; the thicker the wall, the better the pressure-bearing capacity and wear resistance of the pipe, but the cost will also increase. At the same time, the pipe length should be arranged reasonably, considering the convenience of transportation and installation.

(2) Pay attention to technical parameters: Ensure that the pressure level, sanitary standards, and other technical parameters of the plastic-coated steel pipe meet the project requirements. For example, the sanitary performance of the pipe used for drinking water transportation must comply with relevant national standards to ensure that the water quality is not polluted.

(3) Choose a reputable manufacturer: Choose a manufacturer with a good reputation and product quality assurance. You can understand the manufacturer's production equipment, production process, and product quality control system by consulting relevant materials, visiting the production workshop, and understanding customer reviews, so as to ensure that the purchased plastic-coated steel pipe meets the quality requirements.

(4) Consider construction and maintenance factors: Different types of plastic-coated steel pipes have different construction difficulties and maintenance costs. For example, plastic-coated steel pipes with larger inner diameters are more difficult to install and require professional construction teams to carry out the construction; while plastic-coated steel pipes with smaller inner diameters are easier to install and maintain. These factors should be considered comprehensively when making a selection to reduce the overall cost of the project.