Cnhfpipe عرض2 weeks ago - ملابس وموضة - تبوك - 13 الآراء
Fiberglass is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass cloth. The plastic matrix may be a thermoset polymer matrix—most often based on thermosetting polymers such as epoxy, polyester resin, or vinyl ester resin—or a thermoplastic. Cheaper and more flexible than carbon fiber, it is stronger than many metals by weight, non-magnetic, non-conductive, transparent to electromagnetic radiation, can be molded into complex shapes, and is chemically inert under many circumstances. Applications include aircraft, boats , automobiles, bath tubs and enclosures, swimming pools, hot tubs, septic tanks, water tanks, roofing, pipes, cladding, orthopedic casts, surfboards, and external door skins. Other common names for fiberglass are glass-reinforced plastic (GRP), glass-fiber reinforced plastic (GFRP) or GFK (from German: Glasfaserverstärkter Kunststoff). Because glass fiber itself is sometimes referred to as "fiberglass", the composite is also called fiberglass-reinforced plastic (FRP). This article will adopt the convention that "fiberglass" refers to the complete fiber-reinforced composite material, rather than only to the glass fiber within it. Carbon-fiber-reinforced polymer is a similar composite material in which the reinforcement fiber is carbon fibers.
GRP pipe is also called glass fiber wound sand pipe (RPM pipe). It mainly uses glass fiber and its products as reinforcing materials, unsaturated polyester resins and epoxy resins with polymer components as basic materials, and inorganic non-metallic particulate materials such as quartz sand and calcium carbonate as fillers as main raw materials. The standard effective length of the tube is 6m and 12m, and its production methods include fixed-length winding process, centrifugal casting process and continuous winding process. It can be classified according to the product's process method, pressure grade PN and stiffness grade SN. Reinforced plastic with glass fiber or its products as reinforcing material. It is called glass fiber reinforced plastic, or glass fiber reinforced plastic. Due to the different types of resins used, it is known as polyester fiberglass, epoxy fiberglass and phenolic fiberglass. Glass is hard and brittle, with good transparency, high temperature resistance, corrosion resistance and other properties; at the same time, steel is hard and not brittle, and also has the characteristics of high temperature resistance. So people began to think that if a material could be made that not only has the hardness, high temperature resistance, and corrosion resistance of glass, but also has the characteristics of being as hard and unbreakable as steel, then this material will be very useful. After research and experiments, people finally produced such a composite material. It is a glass steel pipe that can stand shoulder to shoulder with steel. GRP pipes are widely used in petroleum, electric power, oil, electricity, electric It has been widely used in chemical industry, papermaking, urban water supply and drainage, factory sewage treatment, seawater desalination, gas transmission and other industries.
Pipe ramming (sometimes also called pipe jacking) is a trenchless method for installation of steel pipes and casings. Distances of 30 m (150 feet) or more and over 1,500 mm (60 inches) in diameter are common, although the method can be used for much longer and larger installations. The method is useful for pipe and casing installations under railway lines and roads, where other trenchless methods could cause subsidence or heaving. The majority of installations are horizontal, although the method can be used for vertical installations. The main differences between pipe ramming and pipe jacking are that pipe ramming uses percussion and does not have a navigation system, while pipe jacking uses hydraulic jacks and does have an active navigation system. Pipe ramming is preferable for shorter distances and applications that do not require tight directional control, such as cable installations. The method uses pneumatic percussive blows to drive the pipe through the ground. The leading edge of the pipe is almost always open, and is typically closed only when smaller pipes are being installed. The shape allows a small overcut (to reduce friction between the pipe and soil and improve load conditions on the pipe), and directs the soil into the pipe interior instead of compacting it outside the pipe. These objectives are usually achieved by attaching a soil-cutting shoe or special bands to the pipe.