Reducers / RED-S
Sudden Reducer
Compact reducer providing high velocity gain through abrupt diameter change.
Technical Specifications
Key Features
- Abrupt cross-section change
- High velocity gain
- Compact structure
- Simple welding design
- Cost effective
- Space saving
Applications
- Pre-nozzle pipelines
- High velocity systems
- Energy recovery units
- Compact piping
- Control valves
- Measurement systems
Dimension Table
| Size | Large Outside Dia. (mm) | Small Outside Dia. (mm) | Thickness (mm) | Length (mm) | Angle |
|---|---|---|---|---|---|
| 2" x 1" | 60.3 | 33.4 | 3.91 | 38 | 90° |
| 4" x 2" | 114.3 | 60.3 | 6.02 | 57 | 90° |
| 6" x 4" | 168.3 | 114.3 | 7.11 | 76 | 90° |
| 8" x 6" | 219.1 | 168.3 | 8.18 | 89 | 90° |
| 12" x 8" | 323.9 | 219.1 | 10.31 | 114 | 90° |
Technical Notes
- 01Causes higher pressure loss.
- 02Generates turbulence.
- 03May lead to cavitation.
- 04Used where space is limited.
What is a pipe reducer?
A reducer is a butt-weld fitting that joins two pipes of different diameters. There are two types: the concentric reducer (aligned centerlines, symmetric cone) and the eccentric reducer (one flat side, offset centerlines). Dimensions follow ASME B16.9; reducers are produced in carbon, alloy and stainless steel from 1/2" to 48".
Concentric or eccentric?
A concentric reducer keeps the pipe centerline and is standard on vertical runs. The flat side of an eccentric reducer keeps either the bottom (BOP) or top of the pipe level on horizontal runs: at pump suction the flat side goes UP so no air pocket can form; on drained lines and pipe racks the flat side goes DOWN so the pipe bottom stays continuous. The ordering notation is "large end × small end" (e.g. 8"×6"); end-to-end lengths are defined in B16.9. Materials: ASTM A234 WPB (carbon), WP11/WP22 (alloy), A403 (stainless), A420 (low temperature); EN 10253 in Europe. Delivered with 3.1 material certificates.
Frequently Asked Questions
What is the difference between concentric and eccentric reducers?+
A concentric reducer has aligned centerlines (symmetric cone); an eccentric reducer has one flat side and offset centerlines, used to keep the bottom or top of a horizontal line level.
Why use an eccentric reducer at pump suction?+
Installed flat side up, it prevents an air pocket forming at the top of the pipe — air pockets at suction can cause pump cavitation.
How do you order a reducer?+
Specify the "large end × small end" combination (e.g. 8"×6"), type (concentric/eccentric), wall thickness (SCH 40, SCH 80...) and material grade.
Which standards cover reducers?+
Dimensions and tolerances per ASME B16.9 (European equivalent EN 10253); materials per ASTM A234 (carbon/alloy), A403 (stainless) and A420 (low temperature).
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