Here are part numbers for o-rings used with molbloc elements and molstic mounting systems.
Optionally, metal gaskets can be used in place of o-rings for connections that are not often changed, or for connections that will be used in excess of 700 kPa (100 psi).
See the attached documents for common fittings to use with molbox, molbloc and molstic flow calibration systems.
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, metal gasket seal, stainless steel,4VCR (1/4 inch VCR) with retainer tabs
3138203 102858, metal gasket seal, stainless steel,4VCR (1/4 inch VCR) without retainer tabs
3138599 102923, metal gasket seal, stainless steel,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.
molbloc storage cases - Hard sided case with custom cut high density foam. Included with all new molbloc elements since about 2005. Protects much better than machined hard plastic cases prior. Specify serial number and model of molbloc element when ordering and product label will be printed for that molbloc element.
3070810 STORAGE CASE, 32 MM MOLBLOC-L: 5E3-L and lower laminar molbloc elements
3070822 STORAGE CASE, 48 MM MOLBLOC-L: 1E4-L, 3E4-L & 1E5-L
3070831 STORAGE CASE, 48 MM MOLBLOC-S: all sonic molbloc-S elements except 5E3-S & 1E4-S
3070846 STORAGE CASE, 80 MM MOLBLOC-S: 5E3-S & 1E4-S
Here is information on VCR Fittings:
1/4 VCR fittings have 9/16-18 threads, https://www.mcmaster.com/9066N23/
7/8-14 threads for 1/2 VCR fittings.
Here are some dies from McMaster Carr:
Thread Repairing Die, 7/8"-14 UNF Right-Hand Thread | McMaster-Carr
Thread Repairing Die, 9/16"-18 UNF Right-Hand Thread | McMaster-Carr