Three-quarter view of a stainless steel reducing coupling on a white background, clearly showing two ends of different diameters.
Side view of the reducer, clearly displaying the length and the contrasting diameters of the two connection ends.
Close-up front view looking into the smaller diameter end of the coupling.
Front-facing view looking into the larger diameter end of the reducing coupling.
Two identical stainless steel reducing couplings placed side-by-side on a white background.
Two reducing couplings positioned at staggered angles, suggesting their use in a pipeline.

Stainless Steel Double Press-Fit Reducing Coupling (Reducer)

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  • Seamless Pipe Size Transition: Engineered to reliably connect two pipes of different diameters in a straight line, ensuring a smooth, turbulent-free flow transition.

  • System Optimization Component: Allows for intelligent downsizing or upsizing within a pipeline, optimizing material use and maintaining desired pressure/velocity.

  • Dual-Diameter, Dual-Seal Reliability: Each end (large and small) employs the same double press-fit O-ring sealing process, guaranteeing independent leak-proof integrity for both connected pipe sizes.

  • Individually Validated Performance: Every reducer is factory pressure tested above 1.05 MPa, certifying the robustness of its transition design.

  • Full Material & Standard Compliance: Constructed from 304/316L stainless steel, conforming to GB/T 19228, ISO 15835, and other international standards.

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Engineered for Intelligent System Transitions and Flow Optimization

The Stainless Steel Double Press-Fit Reducing Coupling is a precision-engineered fitting designed for a fundamental task in piping system design: creating a reliable, straight-line transition between two pipes of different diameters. As part of our versatile Double Press-Fit System Overview, this reducer enables engineers to efficiently step down (or up) pipe sizes within a run, optimizing both hydraulic performance and material economy.

 

The Strategic Role of a Press-Fit Reducer in System Design

Incorporating a dedicated reducer is superior to alternative methods for several reasons:

  • Hydraulic Efficiency: Provides a smooth, concentric transition that minimizes turbulence and pressure drop compared to makeshift solutions, protecting pump efficiency and system performance.

  • Space & Cost Savings: Eliminates the need for multiple fittings (e.g., a coupling plus a separate bushing), saving space in tight installations and reducing total installed cost.

  • Installation Simplicity: A single, pre-engineered component simplifies procurement, installation, and quality assurance on-site.

 

Engineered Integrity at the Transition Point

The junction where diameters change is managed through robust design:

  • Concentric & Reinforced Construction: The fitting is machined to ensure perfect concentric alignment of both bores, with a reinforced body to handle potential stress at the transition.

  • Uniform Sealing Technology: Despite the diameter difference, both ends utilize identical precision O-rings and the proven double-press action. This ensures both seals meet the same high standard of leak-proof performance validated by our System Pressure & Performance Testing.

 

Cross-section Diagram

Cross-sectional diagram of a reducing coupling, cut lengthwise to show the stepped internal bore and O-ring sealing grooves at both the large and small diameter ends.
Sealed Transition: This view reveals how the O-ring seals are independently and reliably formed at both the large and small diameter connections.

 

Uncompromised Quality for Critical Transitions

  • Material & Standards: Fabricated from premium 304, 304L, 316, or 316L stainless steel. Fully compliant with GB/T 19228.1-2011 and ISO 15835.

  • Rigorous Validation: Each reducer undergoes individual pressure testing (>1.05 MPa) and the material is verified through tensile (≥520 MPa) and flattening tests.

 

Specification Table

Model Nominal Diameter Dimensions(mm) Dimensions(inch)
SKZ20*15 DN20*15 20*16 0.787*0.630
SKZ25*15 DN25*15 25.4*16 1.000*0.630
SKZ25*20 DN25*20 25.4*20 1.000*0.787
SKZ32*15 DN32*15 32*16 1.260*0.630
SKZ32*20 DN32*20 32*20 1.260*0.787
SKZ32*25 DN32*25 32*25.4 1.260*1.000
SKZ40*15 DN40*15 40*16 1.575*0.630
SKZ40*20 DN40*20 40*20 1.575*0.787
SKZ40*15 DN40*15 40*16 1.575*0.630
SKZ40*25 DN40*25 40*25.4 1.575*1.000
SKZ40*32 DN40*32 40*32 1.575*1.260
SKZ50*15 DN50*15 50.8*16 2.000*0.630
SKZ50*20 DN50*20 50.8*20 2.000*0.787
SKZ50*25 DN50*25 50.8*25.4 2.000*1.000
SKZ50*32 DN50*32 50.8*32 2.000*1.260
SKZ50*40 DN50*40 50.8*40 2.000*1.575
SKZ60*15 DN60*15 63.5*16 2.500*0.630
SKZ60*20 DN60*20 63.5*20 2.500*0.787
SKZ60*25 DN60*25 63.5*25.4 2.500*1.000
SKZ60*32 DN60*32 63.5*32 2.500*1.260
SKZ60*40 DN60*40 63.5*40 2.500*1.575
SKZ60*50 DN60*50 63.5*50.8 2.500*2.000
SKZ65*15 DN65*15 76.1*16 3.000*0.630
SKZ65*20 DN65*20 76.1*20 3.000*0.787
SKZ65*25 DN65*25 76.1*25.4 3.000*1.000
SKZ65*32 DN65*32 76.1*32 3.000*1.265
SKZ65*40 DN65*40 76.1*40 3.000*1.575
SKZ65*50 DN65*50 76.1*50.8 3.000*2.000
SKZ65*60 DN65*60 76.1*63.5 3.000*2.500
SKZ80*15 DN80*15 88.9*16 3.500*0.630
SKZ80*20 DN80*20 88.9*20 3.500*0.787
SKZ80*25 DN80*25 88.9*25.4 3.500*1.000
SKZ80*32 DN80*32 88.9*32 3.500*1.280
SKZ80*40 DN80*40 88.9*40 3.500*1.575
SKZ80*50 DN80*50 88.9*50.8 3.500*2.000
SKZ80*65 DN80*65 88.9*76.1 3.500*3.000
SKZ100*15 DN100*15 101.6*16 4.000*0.630
SKZ100*20 DN100*20 101.6*20 4.000*0.787
SKZ100*25 DN100*25 101.6*25.4 4.000*1.000
SKZ100*32 DN100*32 101.6*32 4.000*1.2100
SKZ100*40 DN100*40 101.6*40 4.000*1.575
SKZ100*50 DN100*50 101.6*50.8 4.000*2.000
SKZ100*65 DN100*65 101.6*76.1 4.000*3.000
SKZ100*80 DN100*80 101.6*88.9 4.000*3.500
SKZ125*80 DN125*80 133.3*88.9 5.250*3.500
SKZ125*100 DN125*100 133.3*101.6 5.250*4.000
SKZ150*100 DN150*100 159*101.6 6.250*4.000
SKZ150*125 DN150*125 159*133.3 6.250*5.250
SKZ200*125 DN200*125 219*133.3 8.625*5.250
SKZ200*150 DN200*150 219*159 8.625*6.250

 

Primary Applications

  • Connecting different diameter pipes in potable water supply risers and mains.

  • Reducing pipe size before equipment inlets or after pump discharges to optimize flow conditions.

  • HVAC systems for transitions between main distribution lines and branch circuits.

  • Industrial process lines where pipe diameter changes are required.

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