Views: 5 Author: Site Editor Publish Time: 2025-06-18 Origin: Site
In the pipeline system, reducer is an important pipe fitting used to connect pipes of different diameters to achieve a smooth transition of fluids. According to their design and centerline alignment, reducers are mainly divided into two categories: concentric reducers and eccentric reducers.
Each of these two types of reducers has its own unique shape, characteristics and application scenarios. Understanding the difference between these two types of reducers is crucial to designing efficient and reliable fluid delivery systems. Correctly selecting the right reducer is essential to ensure fluid flow efficiency, operational safety and long-term stability of the pipeline system. Contact us
Concentric Reducer
Eccentric Reducer
The concentric reducer is designed in a conical shape with the centerline of the pipe kept consistent. It is suitable for vertical pipes or systems with stable fluid pressure. It can ensure uniform fluid transition and effectively avoid turbulence or pressure loss. It is widely used in pump outlets, vertical pipes and liquid delivery systems.
Smooth fluid flow: Symmetrical design helps reduce fluid turbulence and ensures smooth fluid transition, thereby reducing pressure drop.
Relatively simple installation: Since the centerline remains consistent, it is usually easier to align when installing in vertical pipes.
Compact structure: Compared with some eccentric reducers, its design may be more space-saving.
Vertical Pipelines: This is the main application scenario for concentric reducers. In vertically installed pipes, the gravity effect of the fluid is uniform whether it flows upward or downward, and the concentric design ensures that the fluid is evenly distributed to avoid cavitation or liquid retention.
Gas or Vapor Lines: In pipes that transport gas or steam, the gas is highly compressible and is not easy to form cavitation, so concentric reducers are a common choice, such as in HVAC systems and steam lines.
Vertical Pump Discharge: When the pump outlet is connected to a vertical pipe and the diameter needs to be changed, concentric reducers are often used to ensure smooth discharge of the fluid and reduce turbulence and pressure loss.
Clean Fluid Pipes: For clean fluids without solid particles or low viscosity, concentric reducers can provide the best flow performance and are commonly found in water treatment systems and ordinary water pipes.
Certain Instrument Connections: At the connection of instruments or equipment where the centerline needs to be aligned to ensure measurement accuracy and system stability.
Other Industry Applications: Widely used in industries such as petrochemical, power, food and beverage, where smooth flow systems are required.
A concentric reducer features a symmetrical, cone-shaped design that maintains a consistent centerline between the larger and smaller pipes. This type of reducer is primarily used in vertical piping systems or in situations where air pockets are not a concern.
Installation guidelines:
Always install with the centerline aligned between the two connecting pipes.
Ideal for vertical installations, such as pump discharge lines or risers.
Ensure that the reducer is installed in the direction of flow, from larger to smaller diameter.
Avoid using in horizontal lines where air or condensate accumulation could occur.
The centers of the two ends of the eccentric reducer are not on the same horizontal line, and it is usually used to connect horizontal pipes. Its design can prevent liquid from accumulating at the bottom of the pipe or gas from accumulating at the top of the pipe, and is especially suitable for pump suction ports, drainage systems, or places where gas blockage needs to be avoided.
Prevents cavitation or liquid stagnation: The special design of its straight sides effectively avoids the accumulation of gas (at the top) or liquid/solids (at the bottom) in horizontal pipes.
Simplifies pipe layout: In some cases where it is necessary to keep the top or bottom of the pipe flush, the eccentric reducer can meet the design requirements well.
Horizontal Liquid Pipelines: This is the main application scenario for eccentric reducers.
Horizontal Vapor/Gas Pipelines: When conveying steam or gas, installing the straight side at the bottom can prevent condensate (liquid) from accumulating at the bottom of the pipe, thereby preventing the water hammer effect.
Pump Suction Lines: Almost all horizontal pump suction lines use eccentric reducers (straight side up) to ensure that the liquid is full, avoid cavitation, and improve pump efficiency and life.
Pipes on Pipe Racks/Supports: The straight side of the eccentric reducer makes it easier to keep the bottom or top of the pipe flush when it is laid on the pipe rack or support, which is convenient for support and alignment.
Before control valves or instruments: Before control valves or some instruments, eccentric reducers (straight side down) are sometimes used to ensure that the fluid can flow evenly before entering the equipment and reduce eddy currents.
Other Industry Applications: Widely used in chemical processing plants, refineries and other fields that require precise fluid control and avoid gas-liquid/solid-liquid separation.
An eccentric reducer has a flat side — either top or bottom — depending on the application. This design prevents gas or liquid accumulation, making it ideal for horizontal piping systems.
Installation Tips:
In pump suction lines, install the eccentric reducer with the flat side on top to avoid vapor pockets that could lead to cavitation.
In liquid horizontal lines, install with the flat side on bottom to prevent fluid pooling.
For gas or steam systems, install with the flat side on top to prevent condensation buildup at the bottom.
Ensure proper alignment and slope when installed in horizontal systems to maintain continuous flow.
Feature | Concentric Reducer | Eccentric Reducer |
Shape | Conical / Cone-shaped | Tapered on one side, flat on the other |
Centerlines | Aligned, on the same straight line | Offset, not on the same straight line |
Fluid Flow | Symmetrical, smooth, suitable for gases or vertical liquids | Prevents air pockets/liquid accumulation/solid sedimentation; suitable for horizontal liquids or lines requiring drainage |
Primary Applications | Vertical pipelines, gas/vapor lines, vertical pump discharge, clean fluid lines, etc. | Horizontal liquid pipelines (especially pump suction), lines transporting solids, steam lines (to prevent condensate), piping on pipe racks/supports, etc. |
Installation Orientation | No specific orientation required (for vertical pipelines) | Specific orientation required (flat side up for gas prevention, flat side down for liquid/solid prevention) |
Typical Conditions | Clean fluids, no risk of air pockets/liquid accumulation | Conditions prone to air pockets/liquid accumulation/solid sedimentation |
Concentric reducers are suitable for vertical pipes or pipes conveying gas or steam. The center-aligned design ensures a smooth transition of the fluid and avoids turbulence. However, it is not recommended for horizontal liquid pipes because it can easily cause cavitation or solid precipitation.
Eccentric reducers are the first choice for horizontal pipes. Their straight side design can effectively avoid gas accumulation or liquid/solid retention. The straight side faces up when conveying liquids (to prevent cavitation) and faces down when conveying solid-containing fluids or steam (to prevent precipitation or condensation). Especially at the suction end of the pump, the eccentric reducer ensures stable operation of the pump.
Choosing between concentric and eccentric reducers is crucial for ensuring the efficiency, safety, and longevity of a piping system. It largely depends on the orientation of the pipe and the nature of the fluid being transported.Concentric and eccentric reducers play crucial roles in the functionality and efficiency of pipeline systems in various industries. These pipe fittings optimize fluid flow by regulating pressure, reducing flow rates, and preventing clogs and blockages. The advantages of these reducers are their durability, cost-effectiveness, long-lasting performance, and easy maintenance. It is essential to understand the functions and uses of reducers to ensure the efficiency and longevity of pipeline systems.
