求教，最近刚发布的关于死角的标准

a625680526

前段时间听说刚发布的标准，据说是ASME和WHO的死角标准，3D或者更短，请问有具体的描述么，比如怎么个测量标准。在第几个条款有描述

xiaolong526

坐等达人来解答。。。

Sword

D是盲管直径的意思，这个标准的含义就是盲管顶端到主管外壁的长度不得超过盲管直径的三倍

fang211033

ASME BPE 的标准是2D，有些管径小的很难实现。看情况吧。

beiwei5du

Sword 发表于 2015-7-2 11:22
D是盲管直径的意思，这个标准的含义就是盲管顶端到主管外壁的长度不得超过盲管直径的三倍

想再确认一下，3D是盲管顶端（内壁）与主管内壁的长度不超过盲管直径（内径）的3倍吧！

beiwei5du

Sword 发表于 2015-7-2 11:22
D是盲管直径的意思，这个标准的含义就是盲管顶端到主管外壁的长度不得超过盲管直径的三倍

Dead Leg
Dead legs will be measured by the term L/D, where L is the leg extension from the I.D.（应该理解为interior diameter） wall normal to the flow pattern or direction, and D is the I.D. of the extension or leg of a tubing fitting or the nominal dimension of a valve or instrument. For valves, L shall be measured to the seal point of the valve. If a branch from a primary pipeline has demonstrated flow during cleaning and SIP, it does not constitute a dead leg. （这句话是否理解为，如果主管中的一条支管在清洗或者SIP中有液体流，那么这个支管不被仍为是死角或者盲管）

For high purity water systems, an L/D of 2 or less is attainable with today’s manufacturing and design technology. For other bioprocessing systems, such as purification, filtration, and fermentation having cluster, block, and multi-port valves, an L/D of 2 or less is achievable. However, it may not be achievable with certain equipment and process configurations as they are currently manufactured. For this part, an L/D of 2 or less shall be considered a target ratio, and shall not be construed to be an absolute requirement. （就是说这个 L/D of 2 or less是一个目标比例，不是一个绝对要求）
Publication Source: American Society of Mechanical Engineers (ASME), Bioprocessing Equipment (BPE) - 2012 Revision
Publication Date: 2012
- See more at: http://www.ispe.org/glossary?term=Dead+Leg#sthash.Kan09DXu.dpuf


上文选自ASME

所以个人认为这个primary pipeline的厚度是应该包括在里面的,同时看ASME的下面图示也是包含在内的呢！

Sword

beiwei5du 发表于 2015-8-24 21:02
想再确认一下，3D是盲管顶端（内壁）与主管内壁的长度不超过盲管直径（内径）的3倍吧！

如果你管壁足够厚的话，即使你盲管长度只有1毫米，也是不符合要求的。

Sword

beiwei5du 发表于 2015-8-24 21:44
Dead Leg
Dead legs will be measured by the term L/D, where L is the leg extension from the I.D.（ ...

ISPE建议从主管外壁开始考虑盲管长度。