I have difficulties with sample flow rates when using 3M Empore Oil & Grease disks. Is there anything that I can do?
Yes. There has been three generations of Disk Holder Assemblies. The old style snap fit assembly required one o-ring on the groove of the Insert that would hold the disk in place and form a tight seal. The second generation of Disk Holder Assemblies came in three parts, the Base Cup, the Riser and the Aluminum Locking Ring. No o-ring is needed when using a flat disk. However, when using the 3M Empore Oil & Grease disks the two o-rings are needed to provide a tight seal for optimal flow rates. The larger diameter, thicker o-ring is placed in the bottom outer groove of the Cup and the smaller diameter, thinner, o-ring is placed in the groove of the Riser, which is inserted into the Base Cup to hold the disk in place. The orientation of the Riser is such that the groove with the o-ring is face up and the flat edge is face down on the disk. The Aluminum Locking Ring is then screwed tightly onto this assembly. If the assembly is not tight, when vacuum is pulling, air will flow through the p
