A reducer model is a standardized combined designation for its specification, structure, connection type, material and pressure rating. It mainly complies with Chinese standards (GB/T) and American standards (ASME). Naming rules differ between systems. Clear model interpretations and typical examples are as follows:
I. Core Naming Rules (General Logic)
Basic composition of a reducer model:Structure Type + Bore Size (Large End × Small End) + Pressure/Wall Thickness Rating + Connection Type + Material Note: If no structure type is indicated, concentric reducer is assumed; if no connection type is indicated, butt weld is the default for industrial piping.
II. Chinese Standard (GB/T 12459) Model System (Metric)
1. Core Designation Elements
- Structure type: Concentric (T), Eccentric (P) (optional; concentric by default)
- Bore size: DN Large End × DN Small End (e.g., DN200×DN150)
- Pressure rating: PN + value (e.g., PN2.5, PN4.0)
- Connection type: Butt Weld (BW, default), Flanged (FL), Threaded (TH)
- Material: Carbon steel (20#, Q235B), Stainless steel (06Cr19Ni10/304), Alloy steel (12Cr1MoVG)
2. Typical GB Standard Model Examples
- Example 1: T DN200×DN150 PN2.5 20#Interpretation: Concentric reducer, large end DN200, small end DN150, pressure rating PN2.5, carbon steel 20#, butt weld connection (default).
- Example 2: P DN100×DN50 PN4.0 304Interpretation: Eccentric reducer, large end DN100, small end DN50, pressure rating PN4.0, 304 stainless steel, butt weld connection.
- Example 3: DN50×DN25 PN1.6 FL Q235BInterpretation: Concentric reducer, large end DN50, small end DN25, pressure rating PN1.6, carbon steel Q235B, flanged connection.
III. American Standard (ASME B16.9) Model System (Imperial)
1. Core Designation Elements
- Structure type: Concentric (CON), Eccentric (ECC) (optional; concentric by default)
- Bore size: NPS Large End × NPS Small End (inches, e.g., 4″×2″, 1″=DN25)
- Wall thickness/pressure rating: Sch + number (wall thickness, e.g., Sch40, Sch80) or Class + number (pressure, e.g., Class150, Class300)
- Connection type: Butt Weld (BW, default), Flanged (FL), Threaded (TH)
- Material: ASTM grades (ASTM A234 WPB – carbon steel, ASTM A403 WP304 – stainless steel, ASTM A234 WP11 – alloy steel)
2. Typical ASME Standard Model Examples
- Example 1: CON 4″×2″ Sch40 ASTM A234 WPBInterpretation: Concentric reducer, large end 4″ (DN100), small end 2″ (DN50), wall thickness Sch40, carbon steel ASTM A234 WPB, butt weld connection.
- Example 2: ECC 8″×6″ Class300 ASTM A403 WP316LInterpretation: Eccentric reducer, large end 8″ (DN200), small end 6″ (DN150), pressure rating Class300, 316L stainless steel, butt weld connection.
- Example 3: 2″×1″ Class150 TH ASTM A105Interpretation: Concentric reducer, large end 2″ (DN50), small end 1″ (DN25), pressure rating Class150, carbon steel ASTM A105, threaded connection.
IV. Plastic Reducer Model System (PVC/PPR/PE)
1. Core Designation Elements
- Material: PVC-U, PPR, PE100
- Bore size: De Large End × De Small End (outer diameter, e.g., De110×De75)
- Rating: SDR + number (e.g., SDR11, SDR17, related to pressure)
- Connection type: Socket & cement (PVC), Heat fusion (PPR/PE)
2. Typical Plastic Model Examples
- Example 1: PVC-U De110×De75 SDR26 SocketInterpretation: PVC-U reducer, large end OD 110mm, small end 75mm, SDR26 rating (PN0.6MPa), socket & cement connection.
- Example 2: PE100 De200×De160 SDR11 Heat FusionInterpretation: PE100 reducer, large end OD 200mm, small end 160mm, SDR11 rating (PN1.6MPa), heat fusion connection.
- Example 3: PPR De25×De20 SDR17 Heat FusionInterpretation: PPR reducer, large end OD 25mm, small end 20mm, SDR17 rating (PN1.0MPa), heat fusion connection.
V. Key Notes for Model Selection
- Bore matching: Small end bore ≥ 1/2 of large end bore (e.g., DN100 minimum with DN50) to avoid excessive taper angle causing sharp increase in flow resistance.
- Structure matching: Eccentric (flat bottom) for horizontal pipelines, concentric for vertical pipelines.
- Rating matching: Pressure rating ≥ design pressure of the piping system (e.g., PN2.5/Class300 for 2.5MPa design pressure).
- Standard consistency: Within one piping system, reducer models shall comply with the same standard as pipes, valves and other components (GB and ASME shall not be mixed).
