M O L B L O C / M O L B O X ™ L O W M A S S F L O W C A L I B R A T I O N S Y S T E M A F M E T C A L
C O N F I G U R A T I O N S
I N S T A L L A T I O N A N D O P E R A T I O N M A N U A L S U P P L E M E N T
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5
©2000-2008
DH Instruments, a Fluke Company
m o l s t i c s
molstics are packaged in long corrugated boxes surrounded by protective foam.
Accessory kits are packaged with the molstics and include Viton O-rings,
and installation instructions. Low flow molstic accessory kits also include a filler rod
which can be inserted in the VCR close coupling fitting at the molbloc’s outlet.
The filler is used to reduce dead volume between the molbloc and DUT to help
stabilize pressure when measuring very low flows (see molstic installation
instruction sheet). In systems where there is already significant volume from tubing,
the rod will not have much effect.
Both low and mid flow molstics are delivered with cradles to fit small
molblocs installed. The cradles on the single mid flow molstic need to be replaced
with the large molbloc cradles to fit the larger 30 slm (3E4) molbloc. All of the
molstic parts downstream of the cradles also need to be moved further downstream
to accommodate the 30 slm (3E4) molbloc’s greater length. The molstic base has
pre-drilled holes for each standard bracket and cradle in both positions (see the molstic
installation instructions).
M E T E R I N G V A L V E K I T S
Metering valve kits are made up of several items including the metering valve, a valve
bracket and panel mounting nut, a coupling bracket and grommet, a VCR close
coupling union, two Viton O-rings and Allen screws. Each item in the kit is
packaged in a plastic bag. These kits are to be mounted on the downstream end of
each molstic channel.
Four low flow metering valve kits and one mid/high flow metering valve kit are
delivered. Mount the low flow metering valve kits on the dual low flow and dual mid
flow molstics. Mount the mid/hi flow metering valve kit on the single mid flow
molstic. The manufacturer’s part number written on each metering valve’s body
differentiates the low flow valves from the mid/high flow valve. The low flow valve
is SS-
4BMG
-VCR. The mid/high flow valve is SS-
4BMRG
-VCR. See Section
2.1.2.6 for specific mounting instructions for the metering valve kits.
Never forcefully tighten the molstic metering valves. They are not designed for positive shut-off, only flow
control.
