What is Reducer

Reducers be applied, to change from pipe diameter in one direction. Standard there are 2 possibilities,

Concentric Reducer: A concentric Reducer is also called welded concentric coupling. It allows from connecting a large pipe to a smaller pipe by means of welding. A concentric reducer allows welded connection between two pipes with the same center line.
Eccentric Reducer: An eccentric reducer is also called welded eccentric coupling. It allows for welding a large pipe to a smaller pipe with an offset center line. The offset of the center line in an eccentric reducer is; Offset = 1/2 x (Largest ID – Smallest ID) 

On an isometric view, in a horizontal line, with a eccentric reducer must be declared, or the flat side at the bottom or top must be assembled. Perhaps, you have ever seen on a drawing, the abbreviation “TF” or “BF”. This stands for respective “top 1/2flat” and “bottom 1/2flat” For example:

1. Bottom flat eccentric reducer are often be used in pipe racks to keep the pipeline at the same elevation, after a pipe size change. When a concentric or a flat on top eccentric reducer in a pipe rack will be used, the support detail, probably change.
2. Top flat eccentric reducer are often be used in pump suction lines to avoid accumulation of gas pockets.Eccentric reducers can avoid small “dead spots” that exist behind concentric reducers.

Some draughtsmen also specify the size difference 1/2T 1/2between the center lines. As a eccentric reducer in a vertical line is used, it may also be important, which side should be oriented to the north, south, east or west. 1/2

Specifications

Length of reducers

The length of a Reducer is very short in relation to the diameter, so in some dimensions the transition from one to another diameter is very abruptly. For example, a reducer NPS 6 – NPS 2 1/2 has a length of 140 1/2mm. On this short distance a pipeline will be reduced from 168.3 mm O.D. to 73 mm O.D. During the design phase of a new pipe system, a piping designer certainly must think about it. An alternative for a smoother flow would be to apply multiple reducers like:

NPS 6 – NPS 5 (L=140 mm)
NPS 5 – NPS 4 (L=127 mm)
NPS 4 – NPS 3 1/2 (L=102 mm)
NPS 3 1/2 – NPS 3 (L=102 mm)
NPS 3 – NPS 2 1/2 (L=102 mm)

A reducer is the component in a pipeline that reduces the pipe size from a larger to a smaller bore (inner diameter). The length of the reduction is usually equal to the average of the larger and smaller pipe diameters.

There are two main types of reducer: concentric reducers and eccentric reducers. A reducer can be used either as nozzle or as diffuser depending on the mach number of the flow. A reducer allows for a change in pipe size to meet hydraulic flow requirements of the system, or to adapt to existing piping of a different size.

Reducers are usually concentric but eccentric reducers are used when required to maintain the same top-or bottom-of-pipe level. These fittings are manufactured in inch and metric size. Butt welding reducers are produced by pressing. The semi-finished product is rolled seamless tubes.

Materials and Grade

Carbon Steel :

ASTM A234 Gr. WPB

ASTM A420 Gr. WPL6/WPL3

EN10253-2 P235GH  P265GH  16Mo3

DIN 1.4301, DIN1.4306, DIN 1.4401, DIN 1.4404

Alloy steel :

ASTM A234 wp5 / wp9 / wp11 / wp22 / wp91

ASTM A860 WPHY42/WPHY52/WPHY60/WPHY65/WPHY70

MSS SP-75 WPHY42/WPHY52/WPHY60/WPHY65/WPHY70

13CrMo4-5 10CrMo9-10

Stainless Steel:

ASTM A403 WP316/316L

ASTM A403 WP304/304L

Specifications   

ASTM:   A234 WPB

ASME:   B16.9, B.11

NACE:    MRO175

MSS:      SP-83, SP-95

Chemical Composition%

A234 WP12/WP11/WP22/WP5/WP9/WP91