Concentric Reducer Vs Eccentric Reducer: When To Use Which?

　　Pipe reducers are one of the many types of fitting that can be used to control the flow within a piping system. In a piping system, there are two major types of reducers: concentric reducers and eccentric reducers. We’re going to talk about both types of reducers, what they are, and when you might use them. For the most part, reducing (and expanding) pipes is fairly straightforward. But there are some exceptions that are important to note for the health of a piping system.

　　Reducers can be used simply to adapt pipes of other sizes, but there are also more complicated uses for them. They may need to be used when the flow has to be limited or expanded in a piping system, such as if the hydraulic nature of the piping system demands it. If you’re using a pipe reducer, you need to consider the consequences for the pipe system as a whole, because there will be changes in both flow and pressure.

　　Once you know that you need to use a pipe reducer, you need to make the decision between concentric and eccentric reducers. Most people are going to need to use a concentric pipe reducer, but there are some important reasons why an eccentric pipe reducer might be preferred.

　　A concentric reducer is used to join pipe sections or tube sections on the same axis. The concentric reducer is cone-shaped and is used when there is a shift in diameter between pipes. For example, when a 1" pipe transitions into a 3/4" pipe and the top or bottom of the pipe doesn't need to remain level. This pipe reducer may be used when there is a single diameter change or multiple diameter changes.

　　Unlike eccentric reducers, concentric reducers have a common centerline. Concentric reducers are useful when cavitation is present. Eccentricity occurs when the centerline is offset.

　　An eccentric reducer is a fitting used in piping systems between two pipes of different diameters. The same fitting can be used in reverse as an eccentric increaser or expander. They are used where the diameter of the pipe on the upstream side of the fitting (i.e. where flow is coming from) is larger than the downstream side, and where there is a danger that vapor may accumulate.

　　Unlike a concentric reducer, which resembles a cone, eccentric reducers have an edge that is parallel to the connecting pipe, referred to as the flat side. This parallel edge results in the two pipes having offset center lines. Because eccentric reducers are asymmetrical, they create asymmetrical flow conditions; flow is faster along the angled side, resulting in increased pressure.

　　Horizontal liquid reducers are always eccentric, with the flat side on the top, which prevents the build-up of air bubbles in the system, (unless on control set, same as PV, TV, HV, LV) or in a pipe rack. In a pipe rack, the flat side of an eccentric reducer is on the bottom, so that the position of the bottom of the pipe will be constant, and supported by the rack. Eccentric reducers are used at the suction side of pumps to ensure air does not accumulate in the pipe. The gradual accumulation of air in a concentric reducer could result in a large bubble that could eventually cause the pump to stall or cause cavitation when drawn into the pump.

　　Features of concentric reducers:

　　●Concentric reducers will change kindly between the pump and piping. And concentric reducers are perfectly suitable to use in the exclusion of the pump.

　　●These concentric reducers help to convey slurries and abrasive fluids and are useful to use in operations where corrosion is present.

　　●These concentric reducers are beneficial to use where different ratings and wear protection are required in conveying between flanges or pipes.

　　In Eccentric Reducer, the reduction of the pipe size is achieved by decreasing the diameter of the fitting at a constant rate over a specified length, maintaining one side of the fitting horizontally. An eccentric pipe reducer fitting is manufactured with the smaller outlet off-center to the larger end, which allows it to align with only one side of the inlet. The same fitting can be used in reverse as an eccentric expander.

　　Features of eccentric reducers:

　　●Eccentric reducers have minimum turbulence entrapment and require minimum setting up space.

　　●These eccentric reducers absorb noise which is created by pipe wall and fluid tolerated and decrease noise and vibration.

　　●This type of pipe reducer is utilized with the flat side up in pump pressure to minimize cavitation.

　　Horizontal gas reducers are always eccentric, and bottom flat, which allows condensed water or oil to drain at low points. Reducers in vertical lines are generally concentric unless the layout dictates otherwise.

　　In concentric reducer, the reduction of the pipe size is achieved by decreasing the diameter of the fitting at a constant rate over a specified length, maintaining symmetry around the fitting. Concentric Reducers are used to join pipe or tube sections of different diameters on the same axis. They provide an in-line conical transition between pressurized pipes of differing diameters. Thus, concentric reducers connect pipes of unequal size but have a common centerline. The same fitting can be used in reverse as a concentric expander.

　　Shengtian Group As a professional concentric reducer and eccentric reducer manufacturer, factory, and exporter in China, ABTER STEEL GROUP has accumulated nearly 15 years of experience and expertise in manufacturing ASME, DIN, JIS, and other standard carbon steel reducers, stainless steel reducers, and alloy reducers. Concentric and eccentric reducers cover a wide range of sizes, wall thicknesses, and pressure grades and can be customized according to customer drawings or samples, or special requirements.