What should be paid attention to during the pressure test and flushing of fiberglass pipes?

　　Pressure testing and flushing of fiberglass pipes:

　　① In order to reduce the temporary pipelines added during purging, save pressure testing and purging time, and improve the pass rate of pressure testing and purging, the pipe pressure testing and purging work is carried out according to the system, area, and pressure level. A plan must be prepared to guide the construction before pressure testing and purging.

　　② Clean water is used for pipe pressure testing. When testing and flushing pipes connected to stainless steel pipes, the chloride ion content in the water must not exceed 25 × 10 (25 ppm). The pipe pressure testing and flushing procedures shall comply with the regulations of the general contractor.

　　③ During the pressure test of fiberglass pipes, unauthorized personnel must not enter. After the pressure test is completed, no repairs shall be made on the pipes.

　　④ The following conditions must be met before the pressure test of fiberglass pipes:

　　a. Except for painting and insulation, the pipe installation work within the test scope has been completed according to the design drawings, and the installation quality meets the relevant regulations.

　　b. Welds and other parts to be inspected have not been painted or insulated.

　　c. Temporary restraint devices have been installed on the expansion joints of the pipes.

　　d. The pressure gauge used for the test has been calibrated and is within the cycle. Its accuracy must not be lower than 1.5 level. The full-scale value of the gauge should be 1.5-2 times the maximum pressure to be measured. There should be at least two pressure gauges.

　　What is the function of heating fiberglass pipes?

　　As a heating method required for almost all plastic molding die designs, steel heating for fiberglass pipes can be designed in various forms, such as unidirectional wiring and bidirectional wiring. The materials can be seamless pipes, seam pipes, stainless steel pipes, etc., with low heat loss, high thermal efficiency, and simple wiring. It can be designed as 220V or 380V according to the needs, and the wiring is flexible and diverse. However, due to material and processing limitations, the mold design must consider directional characteristics.

　　(L) The two ends of the heating pipe usually have long cold ends, which cannot play a heating role.

　　(2) The power design of the heating zone should not exceed the limit of 10 watts/cm. The power should not exceed 300 watts, for example, a 30cm long heating pipe. If the design power exceeds this limit, the surface load of the heating pipe is high, and the steel pipe is easily oxidized and corroded, leading to short circuits.

　　(3) It is difficult to use heating pipes in mold designs with temperatures above 250. I once used heating pipes to reach 420, but this molding temperature has high requirements for the quality of the heating pipes, so the circuit opening and short circuit should be checked frequently. Because under such conditions, the heat pipe, wiring terminals, and connected copper and steel media are easily oxidized, leading to opening. Therefore, the electrical transmission medium needs special treatment to avoid the conductive wires being exposed to the air and prolong the life of the conductor.

　　The soldering iron core is generally a type of mold heating pipe, with high power per unit length (generally, a soldering iron core with a diameter of 10 mm and a length of 8 cm can reach a power output of 150 watts), good durability, good safety, and it is not easy to drill holes for embedding. The disadvantage is that the design is difficult to customize, and it is easy to break when disassembled. The circuit design must include insurance measures such as fuses and air switches. The operating area must be kept clean and tidy, with good insulation. Electrical faults should be checked frequently during operation to prevent unnecessary risks.

　　Raw materials for winding molding of fiberglass pipes:

　　The raw materials for winding molding of fiberglass pipes are mainly resins, fiber-reinforced materials, and fillers.

　　(1) Income and expenditure matrix.

　　Resin gas refers to an adhesive composed of a curing agent and resin. The chemical resistance, heat resistance, and natural aging resistance of the winding product mainly depend on the resin properties, and also have a great impact on the processability and mechanical properties. The commonly used resins for winding molding are mainly unsaturated polyester resins, sometimes using bismaleimide resins and epoxy resins. For general civil products (such as cans and pipes), unsaturated polyester resins are mostly used. Epoxy resins can be used for winding products with high requirements for compressive strength and interlaminar shear strength of mechanical properties. Aerospace products mostly use bismaleimide resins with moisture resistance and high toughness.

　　(2) Reinforcement materials.

　　The reinforcing materials used in winding molding mainly include various fiber yarns such as medium-alkali glass fiber yarns, alkali-free glass fiber yarns, high-strength glass fiber yarns, carbon fiber yarns, aramid fiber yarns, and surface felts.