MKS Instruments UK Ltd
Cirrus2 Hardware Manual – SP101017.100 June 2011
37
Fitting a new Orifice Disk
Ensure you have purchased the correct size orifice disk, which should be a 15 Micron, 4-hole array.
P/N. 800010079
Keep the disk in its original packaging until needed.
Do not handle the Orifice Disk, use tweezers gently as not to deform or scratch the disk.
Pay particular attention to the side of the disk that has a black mark, this mark indicates the high pressure side of the
disk.
Offer the new disk to the tapered hole in the inlet flange, marked side facing into the inlet flange, this should be done with
the Tool Guide removed, as the disk needs to be offered as squarely as possible to the hole to avoid fouling.
Without disturbing the new Orifice Disk, carefully re-fit the tool guide to the inlet flange.
Once the guide is secured, check again that the new Orifice Disk is lying squarely in the tapered hole. If not, it must be
re-positioned.