Lined stainless steel composite pipe welding accessories A) the status quo: The current the domestic composite pipe fittings lined stainless steel composite pipe network with the original malleable cast iron pipe fittings composite layer of stainless steel, for solid strength in the two middle inject a layer of plastic. Figure: In this cause: (1) the actual diameter smaller, less traffic, the diameter becomes low a grade as original as DN25 pipeline, flow actually becomes DN20 pipeline; (2) the installation screwed tight grip loose into a degree difficult to grasp, spiral tighten: easily withstood diameter smaller; spiral loosen: the accessories level composite pipe end face torn off easily rust corrosion, pollution medium; (3) Since the compound accessories intermediate layer is a plastic, the use temperature is restricted; (4) In the the lined stainless composite pipe network, due to the limitations of the pipe fittings, lined with stainless steel composite tube range be hampered. B) lined with stainless steel composite pipe welding pipe fittings characteristics: 1 lined with stainless steel composite pipe welded pipe fittings definition and characteristics: Figure: 1) Definition: Composite steel pipe same compliance lined stainless steel as raw materials, and related fittings required to correspond to the requirements of national standards, various types and specifications lined stainless steel composite pipe welded pipe fittings welded using welding methods. 2) Features: (1) parts of the installation of the lined composite pipes welded pipe size is in accordance with the size of the national standards of the parts used in its pipeline; geometry derived in the manufacturing process due to their material tube. (2) lined composite pipe welded pipe fittings welding quality is strictly controlled welding parameters; make weld automatic welding machine, the basic unity of the weld geometry, weld quality is stable and reliable. (3) lined composite pipe welded pipe fittings, pipes easy to install, test in place transparent pipeline network performance unified, stable, reliable, secure. (4) lined composite pipe welded pipe fittings, pipeline network cost and low cost. 2 Classification and Specifications: 1) Connection: (1) trench connected: Groove Tube domestic connection technology, also known as the clamp connection technology, liquid gas pipeline to connect the devaluation, despite the development time of this technology in the country later than other countries, but because of its advanced technology, and soon received by the market. Generally suitable for the working pressure 1.6MPa following diameters ND50 above. Grooved fittings are mainly composed of three parts: Rubber seal ring, clamp and tighten the bolts. Located in the inner layer of rubber seals on the outside of the pipe to be connected, coincides with the pre-roll system of trenches, to fasten the clamp and the outside of the rubber ring, and then with two fastening bolts. Makes the trench connecting member having a good sealing due to the rubber seals and sealably clamps using the unique structural design, and with the tube fluid pressure increased to correspondingly increase its tightness; (2) flange connection: Flange connection is a disk-shaped parts, the most common in the pipeline project, flanges are used in pairs. In the pipeline project, the flange is mainly used for the connection of the pipeline. Need to connect pipes, various mounting a flange, low-pressure pipe can be used silk flange, the use of more than 4 kg pressure welding flanges. Flange connection is the two pipes, pipe fittings or equipment, between the first respective fixed on a flange, the two flanges, plus flange gasket, are fastened together with bolts, and complete the connection. Generally suitable for a working pressure of 2.5MPa or more diameters ND100 more. Flange connection tube composed of: The flange connecting bolts and nuts, the flange gasket, different pressures flanges have different thicknesses and using different bolt flange gasket also have different material from the low pressure asbestos pad pressure asbestos pad to the metal pad has. Flange connection fittings classification: ① flange joint sealing fittings: Common the convex (RF), concave (FM), bump surface (MFM), tongue and groove face (TG), plane (FF) ② flange connecting role in the transition fittings: elbow, tee, cross, reducer, blind panels Flanged pipe connections advantages and requirements: ① flange connection of its advantages is a combination of high strength, easy removal. And standardization, the use according to the nominal diameter of the pipe and nominal pressure to choose; ② flange and pipe connections should meet the following requirements: '[7 X, s3 P "O% p $ z  ○ A flanged end with the pipe centerline vertical;  ○ B two mating flanges between the end faces should be parallel to each other;  ○ C flange sealing surfaces must be smooth process, does not allow defects such as longitudinal grooves and trachoma. D medium temperature and pressure gasket selection correctly, an interface will only be allowed to place a gasket, the inner diameter of the gasket must not be less than the inner diameter of the tube, an outer diameter not greater than the flange recessed portion of the screw hole of diameter or not obscure concentric and pipe installation. + D; j; Flange connection fittings Scope: (1) can be used to fire water system, air conditioning, hot and cold water system, water supply system, petrochemical, pipeline system, thermoelectric and military industrial piping systems, sewage treatment pipeline system, etc.; (2) can be used to connect steel pipe, stainless steel pipe, plastic-lined steel pipe, ductile iron pipe, thick-walled plastic tube and hose with a steel pipe fittings and flange joint and valve pieces. C) advanced technology content: (1) lined with stainless steel composite pipe welded pipe fittings; (2) lined with stainless steel composite pipe welding pipe fittings cutting technology; (3) lined stainless steel welded pipe fittings composite pipe welding technology.