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通径在各国、各行业标准中都各有解读。公称通径是一个圆整数它和实际通径不完全相同,它以不同形式的阀门和不同公称压力、不同规格尺寸来划分为缩径、不缩径及全通径、流通直径。我国按GB/T12237、GB/T12238、GB/T7746来执行。
美国的通径划分。按美国国家标准ANSI.B16.1；美国工程师协会ASME.B16.34；美国石油协会AP16D；标准以不同的压力规定不缩径的最小流通直径。
英国的通径体系划分以BS5351规定了球阀、通孔阀和不同的压力等级划分最小流通直径。
日本的通径体系划分以JIS.2001规定了通用阀门、船用、室外下水道通用，以不同的压力等级划分流通直径，以我国标准为例。 |
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There are different understandings for DN in different countries. It is an integer which is a little different from practical diameter.It is divided into reduced bore, non-reduced bore,full bore and flow diameter by different valve, nominal Preassure, spec sizes. It is carried out by GB/T12238、GB/T7746 in China.
American standard.ANSI.B16.1;ASME.B16.34;AP16D.
Inch system is applied to BS5351.
Japanese diameter system conform to JIS.2001. |
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钢制球阀阀体的最小流道直径 The Minimum Flow Diameter
(GB/T12237-1989)(mm)
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公称通径
DN
Nominal Diameter
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阀体的最小流道直径 The minimum Flow Diameter
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缩径 Reduced Bore
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不缩径 Non-Reduced Bore
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公称压力/MPA
Nominal Pressure
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1.6. 2.5. 4.0. 6.4.
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10
|
|
10
|
-
|
9
|
9
|
|
15
|
9.5
|
12.5
|
12.5
|
|
20
|
12.5
|
17
|
17
|
|
25
|
17
|
24
|
24
|
|
32
|
23
|
30
|
30
|
|
40
|
28
|
37
|
37
|
|
50
|
36
|
49
|
49
|
|
65
|
51
|
64
|
64
|
|
80
|
57
|
75
|
75
|
|
100
|
76
|
98
|
98
|
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