thuba PS 830 Manuel page 23

Manual BVS 19 ATEX E 080 X
Figure 1 Block diagram
3.2 Purging period
3.2.1 Pressurized enclosure system without
pre-purging
If the operator is sure, that the atmosphere inside
of the enclosure and the appropriate pipe infras-
tructure is below 25% of the lower explosive limit
(LEL) (IEC 60079-14 chapter 13.4) at power up,
he can abandon the pre purging of the enclosure
in zone 2. In that case the PS 830 monitors only
the pressure inside of the enclosure on 0.8 mbar
at minimum and maximal 22.0 at maximum. If
any limit is exceed, the PS 830 changes the
state on relay(s) output(s).
The purge medium flows through an adjustable
sinter metal throttle into the housing while reduc-
ing its pressure (see block diagram). The LA 830
has an mechanical output valve which opens at
approximately 5 mbar to let the purge medium
out. Before this valve is a spark lattice located
thus the purge medium can be exhausted direct-
ly to the hazardous area.
Edition July 2020
Copyright
Control unit PS830
图1框图
3.2 吹扫周期
3.2.1 没有预吹扫的正压系统
如果操作人员确信，外壳内的空气和适当的管道
结构在通电时低于爆炸下限(LEL)(IEC60079-
14第13.4章)的25%，他可以放弃2区外壳的预
吹扫。在这种情况下，PS830只监测外壳内的
压力在0.8mbar的最低和最22.0。 如果超过任
何限制，PS830将改变继电器输出的状态。
在降低其压力（见方框图）时，吹扫介质通过可
调节的烧结金属节气门流入外壳。 LA830有一
个机械输出阀，它在大约5mbar处打开，让吹
扫介质出来。 这个阀门是一个火花晶格构造，
因此吹扫介质可以直接排放到危险区域。
19
thuba Ltd., CH-4002 Basel
Switzerland