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Products Description
Flange: The Key Hub for Connecting Pipes and Equipment
In the connection of industrial pipeline systems, mechanical equipment, and various pressure-bearing devices, flanges (referred to as flanges for short) have become indispensable core connectors due to their detachable, strong sealing, and high load-bearing capacity. Through standardized structural design, it closely combines originally independent components such as pipes, valves, and pump bodies to form a stable fluid transmission or pressure-bearing system, which is a typical representative of connection technology in modern industrial production.
I. Material Selection: Performance Guarantee for Adapting to Diverse Working Conditions
The material of the flange needs to be comprehensively selected according to factors such as the pressure, temperature, and medium characteristics of the service environment. Common types include:
- Carbon steel flanges: Low in cost and high in strength, suitable for general industrial pipelines with normal temperature and medium-low pressure, such as water and gas transmission pipeline systems;
- Stainless steel flanges (such as 304, 316 materials): Have excellent corrosion resistance, can resist corrosive media such as acids, alkalis, and salt spray, and are widely used in chemical, food, pharmaceutical and other fields with strict requirements on hygiene and corrosion resistance;
- Alloy flanges: By adding alloying elements such as chromium, molybdenum, and nickel, the high-temperature strength and oxidation resistance are improved, and they are often used in high-temperature and high-pressure petroleum and power pipeline systems;
- Non-metallic flanges (such as plastic, glass fiber reinforced plastic): Light in weight and strong in corrosion resistance, but with low pressure-bearing capacity, suitable for civil or light industrial scenarios with low pressure and corrosive media, such as sewage treatment pipelines.
Regardless of the material, the processing of the flange must ensure the flatness and smoothness of the surface to ensure the tight fit of the sealing surface and prevent medium leakage.
II. Core Functions and Application Scenarios
The core function of the flange is to realize the detachable rigid connection of two components and ensure the tightness of the connection part. The specific applications are reflected in:
- Pipeline connection: In long-distance pipeline laying, segmented pipelines are connected into a whole through flanges, which is convenient for later maintenance and repair; when the pipeline needs to turn, reduce diameter, or branch, flange connections can flexibly adapt to various pipe fittings (such as elbows, tees, reducers);
- Equipment docking: Connect pumps, valves, pressure vessels and other equipment with the pipeline system. For example, the water inlet and outlet of the water pump are connected with the water transmission pipeline through flanges, and the valve realizes the on-off control of the pipeline through flanges;
- Sealing and pressure bearing: The flange sealing surface cooperates with gaskets (such as rubber gaskets, metal wound gaskets) to form a sealed cavity under the action of bolt fastening force, preventing the leakage of liquid, gas or dust in the pipeline, especially suitable for high-pressure, flammable, explosive or toxic medium transmission systems.
From municipal water supply and heating pipe networks to petrochemical process pipelines, from thermal power generation steam systems to ship power pipelines, flanges play a key role as "connection hubs".
III. Structural Types and Connection Methods
The structural design of the flange needs to adapt to different connection requirements. Common types are:
- Slip-on flanges: The flange and the pipeline are connected by flat welding, which is simple to manufacture and low in cost, suitable for low-pressure working conditions;
- Weld neck flanges: The welding groove between the flange and the pipeline is V-shaped, with high welding strength, suitable for high-pressure and high-temperature pipeline systems;
- Socket weld flanges: The pipeline is inserted into the inner hole of the flange for welding, with good sealing performance, mostly used for small-diameter, high-pressure pipeline connections;
- Threaded flanges: Connected with the pipeline through threads, no welding is required, and installation is convenient, suitable for scenarios where open flames are not allowed (such as flammable and explosive environments).
The connection method follows a unified process: align the sealing surfaces of the two flanges, place a gasket in the middle, then evenly fasten the screw holes on the flange with bolts, and make the gasket undergo elastic or plastic deformation through the pre-tightening force of the bolts to fill the tiny 凹凸 (unevenness) of the sealing surface, thereby achieving reliable sealing.
IV. Specification Standards: Versatility Brought by Standardization
The specifications of flanges take the nominal diameter (DN) and nominal pressure (PN) as the core parameters, following international or industry standards (such as GB, ANSI, DIN, etc.):
- The nominal diameter (such as DN100, DN200) corresponds to the outer diameter of the connected pipeline to ensure the size matching between the flange and the pipeline;
- The nominal pressure (such as PN1.6MPa, PN10MPa) indicates the maximum working pressure that the flange can bear, which determines its thickness, bolt specifications and other strength designs.
Standardized specifications make flanges produced by different manufacturers interchangeable, which greatly improves the assembly efficiency and maintenance convenience of industrial systems.
Summary
Although the flange seems to be a simple metal disc, it embodies the wisdom of industrial connection technology. It adapts to complex working conditions with various materials, realizes universal connection with standardized structures, and ensures system safety with reliable sealing performance, becoming a model of "small components supporting large systems" in industrial production. In the field of fluid transmission and equipment connection, the existence of flanges makes the construction, maintenance and upgrading of complex systems efficient and controllable, and it is an indispensable basic connector in modern industry.
