Here are part numbers for o-rings used with molbloc elements and molstic mounting systems. Metal gaskets can be used for connections that are not often changed, or for connections that will be used in excess of 700 kPa (100 psi).
Part Number Description
3071123 O-rings, 4 VCR (1/4 inch VCR), Viton, brown, 70 durometer, kit of 50
3071138 O-rings, 8 VCR (1/2 inch VCR), Viton, brown, 70 durometer, kit of 50
3135759 102183,Seal,SS,4VCR (1/4 inch VCR) with retainer tabs
3138203 102858,Seal,SS,4VCR (1/4 inch VCR) without retainer tabs
3138599 102923,Seal,SS,8VCR (1/2 inch VCR) with retainer tabs
1/2 inch metal gaskets without retainer tabs are not available from Fluke Calibration but are available from Swagelok (see part numbers at the end of article)
1/4 inch o-rings are used with laminar molbloc flow elements ranges 1E1 through 3E4, and with sonic flow nozzles ranges 1E1-S through 1E2-S. They are brown Viton, durometer 70, and are size 2-202 o-rings with these dimensions:
o-ring size -202, O.D. 0.512 in., I.D. 0.234 in., C.S. 0.139 in.
o-ring size -202, O.D. 13 mm, I.D. 5.9 mm, C.S. 3.5 mm
1/2 inch o-rings are used with laminar molbloc flow element 1E5, and with sonic flow nozzles ranges 2E1-S through 2E3-S. They are brown Viton, durometer 70, and are size 2-207 o-rings with these dimensions:
o-ring size -207, O.D. 0.824 in., I.D. 0.546 in., C.S. 0.139 in.
o-ring size -207, O.D. 20.9 mm, I.D. 13.9 mm, C.S. 3.5 mm
See these documents for instructions on mounting molbloc elements to molstic mounting systems. It is important to not over-tighten connections sealed with o-rings,
O-ring installation instructions summary: Rotate the nut until resistance is felt when the o-ring begins to compress. Holding the molbloc with your hand, tighten the nut an additional 1/2 turn. A wrench may be used on the nut if desired, but do not tighten beyond one half turn. If more than one half turn is needed to make a leak free connection, the o-ring may be damaged and should be replaced.
Parts can be ordered by contacting the Orders Group at +1.877.355.3225 or email to Orders Group
Flow Technical Support can be contacted at that same number or by email to Flow Support
Swagelok metal gasket part numbers are SS-4-VCR-2, SS-4-VCR-2-GR-VS, SS-8-VCR-2, and SS-8-VCR-2-GR.
Brown Viton (durometer 70) o-rings size 2-202 (1/4 inch) or 2-207 (1/2 inch) should be available from any o-ring supplier.
Stainless steel VCR gaskets, without and with retaining tabs.