Flanged reducers are used for diameter transition between large pipes and small pipes in piping systems, with flanges at both ends, connected by bolts and sealing gaskets, no hot work welding is required on site, and later disassembly, assembly, and maintenance are also convenient. Products are divided into two structures: concentric and eccentric: the concentric type is mostly used for diameter reduction of vertical risers, and the eccentric type is used for horizontal pipelines, which can avoid accumulation of gas or liquid in the pipe and reduce the risk of gas blockage and water hammer. The internal conical flow passage transitions smoothly, which helps stabilize the medium flow rate, reduce local pressure drop and pipe wall erosion. It implements standards such as GB/T17185, GB/T12459, HG/T21635, ASME B16.5, with diameter DN15~DN1200, pressure covering PN6~PN100, Class150~Class1500, and materials include 20# carbon steel, Q235B, Q345B, 304/304L/316/316L stainless steel, 16Mn alloy steel, ductile iron, and special materials such as duplex steel and Hastelloy can also be customized according to the project.
Overview
Flanged reducer is a pipe fitting used for pipe diameter transition in pipeline systems. Both ends are integrally provided with flanges, and the connection is achieved by bolts plus sealing gaskets, without the need for on-site welding. Its function is to connect pipes of different nominal diameters, allowing a smooth transition between large pipes and small pipes, adjusting medium flow velocity, reducing local pressure drop, and solving the problem of diameter mismatch among pipelines, pumps, valves, and equipment. By structure, it is divided into concentric flanged reducers and eccentric flanged reducers: the concentric type is mostly used for diameter reduction of vertical risers; the eccentric type is used for horizontal pipelines, which can avoid the formation of gas pockets and liquid accumulation inside the pipeline and reduce the risk of water hammer. The products comply with standards such as GB/T17185, GB/T12459, HG/T21635, and ASME B16.5, with diameters from DN15 to DN1200, pressure coverage from national standard PN6 to PN100 and American standard Class150 to Class1500, and materials including 20# carbon steel, Q235B, Q345B, 304/304L/316/316L stainless steel, 16Mn alloy steel, and ductile iron. Special materials such as duplex steel and Hastelloy can also be customized according to project requirements.
Key Features
The main features of flanged reducers are concentrated in the connection method and structural design. Both ends have integrated flanges, and bolted connection requires no hot work welding, making construction safe and efficient, and there is no hidden danger of weld cracking and leakage, while later disassembly, assembly, and maintenance are convenient. The internal conical flow channel provides a smooth transition, the medium flow velocity is stable, and the pressure drop is small, which can reduce turbulence, water hammer, and pipe wall erosion. In terms of selection, the concentric and eccentric structures can respectively correspond to vertical risers and horizontal pipelines, and the eccentric type can avoid the accumulation of gas or liquid in the pipeline. In terms of specifications, diameters from DN15 to DN1200, pressures from PN6 to PN100 and Class150 to Class1500, multiple materials, and RF/MFM/TG/RJ sealing surfaces are optional, and diameter reduction at any diameter at both ends is supported, enabling matching with different pipeline designs.
Applications
Flanged reducers are used in pipeline diameter transition scenarios, covering civil buildings, municipal engineering, industrial chemical, electric power and heating, and environmental protection wastewater pipeline network systems of various types. Civil scenarios include diameter reduction of building water supply and drainage pipelines, diameter conversion of central air conditioning circulating water pipes, diameter reduction at pump inlet and outlet of building fire protection pipelines, and matching of equipment interfaces in machine rooms. Municipal scenarios are suitable for diameter reduction of main and branch pipes of urban water supply, diameter transition of municipal heating pipeline networks, and diameter reduction connection of rainwater and sewage pipelines. Industrial scenarios are used for chemical process pipelines, power plant circulating water systems, wastewater treatment plant pipelines, and oil and gas transmission pipelines. Concentric reducers are mostly used for diameter reduction of vertical risers, while eccentric reducers are suitable for horizontal pipelines, can avoid the accumulation of gas or liquid in the pipeline, prevent gas pockets and water hammer, and are mostly used for pump inlet and outlet pipelines. They are also suitable for connection and renovation of new and old pipeline networks, adaptation of inlet and outlet pipelines of large equipment, and 24-hour continuous operation circulating pipelines, and can transport clean water, circulating water, steam, gas, oil products, wastewater, and acid-base chemical media.
Specifications
Flanged reducers follow standards such as GB/T17185, GB/T12459, HG/T21635, and ASME B16.5, and are divided into concentric flanged reducers and eccentric flanged reducers. The diameter range is DN15 to DN1200, diameter reduction at any diameter at both ends is supported, and wall thickness grades are SCH10, SCH40, SCH80, and ST. Forming processes include hot pressing, forging, and integral casting. The connection method is flanged bolted connection, and sealing surfaces include RF raised face, MFM male and female face, TG tongue and groove face, and RJ ring joint face. Pressure coverage includes national standard PN6 to PN100 and American standard Class150 to Class1500. Materials include 20# carbon steel, Q235B, Q345B, 304/304L/316/316L stainless steel, 16Mn alloy steel, and ductile iron, and special materials such as duplex steel and Hastelloy can also be customized. They can transport water, steam, gas, oil products, wastewater, and acid-base chemical media. Each piece undergoes factory inspection for appearance, dimensions, and hydrostatic pressure, with no porosity or sand holes, dimensional tolerances meeting standards, and stable pressure-bearing performance, satisfying pipeline diameter reduction connections under conventional and high-temperature, high-pressure, and corrosive working conditions.
Procurement & Delivery
Flanged reducers adopt a flexible minimum order mechanism, with no excessively high procurement threshold, adapting to various needs such as sample submission for inspection, sporadic maintenance, project centralized procurement, and foreign trade export. Standard specifications in regular stock can be ordered from 1 piece, including PN16 and PN25 pressures, carbon steel and 304 stainless steel concentric and eccentric reducers, which can meet the needs of construction site emergency repairs, local pipeline renovation, sample submission for inspection, and sporadic accessory replacement. The delivery time is set in a three-level system of stock, regular orders, and non-standard customization, matching construction progress and foreign trade shipping schedules: the warehouse keeps mainstream stock, PN10, PN16, and PN25 regular pressures, and commonly used carbon steel and 304 stainless steel concentric and eccentric reducers, and shipment is arranged within 24 hours after order confirmation; for regular standard orders without special processes and non-standard customized delivery times, please contact us for confirmation. Packaging adopts graded industrial protection: carbon steel parts are sprayed with anti-rust oil, stainless steel parts are given anti-oxidation isolation protection, and flange sealing surfaces are pasted with special protective rubber pads; small diameters are individually wrapped in bubble film and packed into hard cartons, medium diameters are reinforced with multi-layer wrapping film, and large-diameter heavy reducers are fixed on solid wood pallets, locked with steel straps, and wrapped with an outer waterproof film. The outer packaging is marked with product name, large and small diameters, material, pressure grade, executive standard, and production batch. For foreign trade orders, fumigated wooden pallets and customized shipping marks can be provided, adapting to various transportation modes such as less-than-truckload, full truckload, sea freight, and air freight.
Service & Support
We provide full-process after-sales service for flanged reducers. Products undergo 100% quality inspection before leaving the factory, and genuine products enjoy a 12-month warranty service. During the warranty period, for quality problems such as cracking, leakage, deformation, and wall thickness defects caused by non-human impact or illegal use under overpressure, free replacement and reissue are supported, and round-trip logistics costs are borne by us. Before sale, free services are provided for pipeline diameter reduction selection, hydraulic parameter verification, drawing adaptation, and budget quotation; during sale, production, quality inspection, and shipping progress are synchronized in real time; after sale, installation guidance, pipeline operation and maintenance optimization plans, and technical answers for troubleshooting are provided. For large engineering projects, remote technical disclosure and full-process technical follow-up can be provided. Unused standard products with intact packaging support seven-day no-reason return and exchange. After-sales response is fast, problems are addressed within 2 hours, solutions are issued on the same day, and free technical consultation is provided for life, assisting in solving technical problems such as pipeline installation and working condition selection. The factory has one-stop customization capability and can undertake customization of non-standard sizes, special working conditions, and special processes: customization of diameter reduction ratios at any two end diameters is supported, pressure grades can be customized to national standard PN6 to PN100 and American standard Class150 to Class1500 specifications, materials can be customized to special alloys such as 2205 duplex steel, Monel alloy, and Hastelloy, sealing surfaces can be customized to multiple structures such as RF, MFM, TG, and RJ, surface processes support sandblasting, blackening, hot-dip galvanizing, pickling and passivation, and mirror polishing, and laser marking can engrave LOGO and project numbers. Production can be carried out according to customer drawings and technical agreements, with one-on-one technical connection.
FAQ
How to choose between concentric flanged reducers and eccentric flanged reducers?
Concentric reducers are mostly used for diameter changes in vertical risers; eccentric reducers are suitable for horizontal pipelines, can avoid gas or liquid accumulation in the pipeline, prevent air pockets and water hammer, and are mostly used in pump inlet and outlet pipelines. Selection needs to be comprehensively judged in combination with pipeline routing and medium characteristics. You are welcome to contact us for assistance in confirmation.
Do flanged reducers require on-site welding?
No. Both ends of the product come with integrated flanges, connected by bolts plus sealing gaskets. No hot work welding is required on site, disassembly and maintenance are convenient, and the hidden danger of weld cracking and leakage is also reduced.
What diameters, pressures, and materials are available for flanged reducers?
The diameter range is DN15~DN1200, supporting arbitrary diameter reduction at both ends; pressure covers national standard PN6~PN100 and American standard Class150~Class1500; materials include 20# carbon steel, Q235B, Q345B, 304/304L/316/316L stainless steel, 16Mn alloy steel, ductile iron, and special materials such as duplex steel and Hastelloy can also be customized. Please contact us to confirm specific specifications.
What are the minimum order quantity and delivery time for flanged reducers?
Standard specifications in regular stock start from 1 piece, including PN16 and PN25 pressures, carbon steel and 304 stainless steel concentric and eccentric reducers. The warehouse keeps mainstream stock items on hand, and shipment is arranged within 24 hours after order confirmation; for regular standard orders without special processes and for non-standard customized delivery times, please contact us for confirmation.
Can flange reducers be customized according to drawings?
Yes. We support customization of any two-port diameter reduction ratio and non-standard size customization. Pressure rating, material, sealing face, and surface process can all be confirmed according to project requirements. We can produce according to customer drawings and technical agreements, and provide one-on-one technical support.
