Concentric and Eccentric Reducer

Concentric and Eccentric Reducer are two types of reducer. Reducer is fittings to change the pipe diameter in the same direction. There are two types: concentric reducer, usually used for vertical pipelines. Eccentric reducer, usually used for horizontal pipelines.

Eccentric Reducer

In horizontal pipelines, if use eccentric reducer, there are two installations: top level TF (Tops flat) and bottom flat bf (bottom flat). For example:

1. Bottom Flat Eccentric Reducer is common in the pipe gallery, to maintain the line on the same elevation. If you use a concentric reducer or a top flat eccentric reducer, the Tube gallery support will be changed.
2. The Top Flat Eccentric Reducer is more suitable for the suction line of the pump, the top level of the pipeline, the bubble will not accumulate in the pipeline.

Some cartographic staff often indicate the variable T of the pipeline center line in the drawing. When the eccentric reducer is used in the vertical pipeline, the orientation of the eccentric reducer is also a very important problem. See below drawing

The length of the reducer has little relation with the change of pipe diameter. Therefore, some of the larger diameter of the reducer may cause fluid sudden change. For example: 6 “-2 1/2” of the reducer length is 140 mm, in such a short distance, pipe diameter is from 168.3 mm to be 73 mm. In the design phase of a piping system, piping design engineers will certainly consider such issues.

The alternative is to increase the use of the reducer, for example:

• NPS 6 – NPS 5 (L=140 mm)
• NPS 5 – NPS 4 (L=127 mm)
• From NPS 4 to NPS 3½, L=102 mm
• From NPS 3½ to NPS 3, L=102 mm

In the above scenario, the total distance from 6 “to 2 1/2” is extended to 573 mm, and the smooth transition of the fluid is ensured. In practice, similar examples may never have occurred.

Reducer Weight Chart

DN	NPS	10S	20	STH	40	XS	80	100	120	140	160	XXS
15	1/2	0.05		0.08	0.08	0.1	0.1
20	3/4	0.1		0.17	0.17	0.2	0.2
25	1	0.13		0.21	0.21	0.25	0.25				0.22
32	1 1/4	0.2		0.29	0.29	0.35	0.35
40	1 1/2	0.28		0.42	0.42	0.58	0.58				0.6
50	2	0.45		0.8	0.8	1.03	1.03				1.04
65	2 1/2	0.55		1.05	1.05	1.42	1.42				1.65
80	3	0.74		1.36	1.36	1.9	1.9
90	3 1/2	0.84		1.63	1.63	2.27	2.27				2.4
100	4	1.38		2.77	2.77	4	3.93				4.4
125	5	1.85		3.96	3.96	6	6				7.14	8.62
150	6	2.8		6.31	6.31	5.95	9.26				10.8	12.6
200	8	4.6	7.85	10.7	10.7	9.26	17.5		15		18.4	17.9
250	10	7	11.2	15.8	16.3	14.5	25.1	21.7	25.1	29.3	32.5	29.3
300	12	14	25.6	28.8	32.1	21	56.5	35.7	41.7	46.3	53.3	41.7
350	14	17.5	30.5	38.5	48.8	37.1	79	73.3	84.5	95.4	106
400	16	21.5	35.2	44.5	64.3	48.8	102	96	112	130.5	143
450	18	36	62.7	62.7	98.5	58.5	165
500	20	38	72.6	72.6		80.4	181
550	22	47.5	97	79.1	142	93.8	226
600	24		130	100		101
650	26		142	110		130
700	28	85	152	119		142
750	30		161	125	208	152
800	32		171	132	231	161
850	34		180	140	262	171
900	36			148		180
950	38			156		194
1000	40			178		203
1050	42			189		235
1100	44			199		244
1150	46			210		257
1200	48			223		269
1300	52			241
1400	56			258
1500	60			1018