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公制英制傻傻分不清楚

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公制英制傻傻分不清楚

Postby admin » Fri Jul 07, 2017 12:02 am

管材
http://bbs.hcbbs.com/thread-127548-1-1.html
公称直径(nominal diameter),又称平均外径(mean outer diameter)。
这是缘自金属管的管璧很薄,管外径与管内径相差无几,所以取管的外径与管的内径之平均值当作管径称呼。
因为单位有公制(mm)及英制(inch)的区分,所以有下列的称呼方法。
1. 以公制(mm)为基准,称 DN (metric unit)
2. 以英制(inch)为基准,称NB(inch unit)
3. DN (nominal diameter)
NB (nominal bore)
OD (outside diameter)
4. 【例】
镀锌钢管DN50,sch 20
镀锌钢管NB2”,sch 20
5. 外径与DN,NB的关系如下:
------DN(mm)--------NB(inch)-------OD(mm)
15-------------- 1/2--------------21.3
20--------------3/4 --------------26.7
25-------------- 1 ----------------33.4
32-------------- 1 1/4 -----------42.2
40-------------- 1 1/2 -----------48.3
50-------------- 2 -----------60.3
65-------------- 2 1/2 -----------73.0
80-------------- 3 -----------88.9
100-------------- 4 ------------114.3
125-------------- 5 ------------139.8
150-------------- 6 ------------168.3
200--------------- 8------------219.1
上面数据依ASTM A53仅共参考。规范不同,外徑会有些许差异,请注意。


icetide :
有时因为耐压等级不同,管壁就有薄厚之分,例如同叫Φ219的管道,壁厚有多种规格,但选DN200的法兰连接方式仪表都可以安上。
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Re: 公制英制傻傻分不清楚

Postby admin » Sat Jul 15, 2017 7:10 pm

https://www.pharmacy-tech-study.com/measurements.html
Pharmacy Measurement Conversions


In pharmacy, measurement conversions
of units from one system to another is very common.
You'll want to study all of the different pharmacy conversions to prepare for the PTCB or ExCPT exams. However, I would recommend committing what you would consider the most commonly used to memory first. If you can eventually memorize them all, that's great too.


Liquids


1cc = 1 mL
5mL = 1 tsp
15mL = 1 tbsp
30mL = 1 oz
480 mL = 1 pt
3785 mL = 1 gal


Look at the above conversions, notice the progression of the measurements. Now look at the next conversions and hopefully you will start to see the patterns.


3 tsp = 1 tbsp
2 tbsp = 1 oz
16 oz = 1 pt
2 pt = 1 qt
4 qt = 1 gal
1 Liter = 1000 ml (metric)


Mass / Dry / Solids



1 Kilogram = 1000 Grams
1 Gram = 1000 Milligram
1 Milligram = 1000 Micrograms


1 kg = 2.2 lbs
1 lbs = 454 gm
1 oz = 30 gm
16 oz = 1 lb


The Metric system is the most commonly used in pharmacy and all that is used in Chemistry. Surprisingly, the U.S. has never standardized to it with the rest of the world.

Microgram mcg
Milligram mg
Gram gm or G
Kilogram kg





Insulin units

100 IU
per/mL
(100 int'l units)
(per milliliter)
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