molbloc, molbloc-S, molbox, molstic and molstic-s are trademarks, registered and otherwise, of
DH Instruments, Inc.
VCR is a registered trademark of the Swagelok Company.
Document 560065
030425
DH Instruments, Inc.
4765 East Beautiful Lane
Phoenix AZ 85044-5318
USA
Tel 602.431.9100
Fax 602.431.9559
www.dhinstruments.com
SYSTEM PRESSURIZATION AND
REGULATOR ADJUSTMENT
During system operation, be extremely careful
not to apply pressure in excess of the maximum
operating pressure of the molbox: 600 kPaa
(87 psia) for molbox1-A700K; 250 kPaa (36 psia)
for molbox1-A350K.
Once the test system with molbloc-S and molstic-S has been
completely interconnected, the following procedure should
be used for its safe pressurization and operation.
The outlet pressure of a pressure reducing regulator is
controlled by adjusting the position of the control knob.
Rotating the knob in the clockwise direction raises the outlet
(control) pressure. Counterclockwise rotation, coupled with
venting of the downstream side of the regulator plumbing,
lowers the outlet pressure. molstic-S regulators are NOT
self-venting so the outlet pressure will not decrease with
counterclockwise rotation of the control knob unless the
downstream gas is allowed to escape.
Make final adjustments of control pressure in the direction of
increasing pressure in order to obtain the most accurate and
stable set point.
System Pressurization
Set inlet pressure to minimum:
Turn the regulator’s
adjustment knob counterclockwise until the spring force
has been relieved, and if so equipped close the shut-off
directly downstream of the pressure control regulator.
Open molstic-S flow control/shut off valve(s):
Valves must be open to allow test gas to fill the test
system.
Plug-off/cap-off system:
Place a cap or plug
(as applicable) on the outlet fitting of the test system.
Isolate from vacuum system:
If the outlet plumbing of
the molstic-S flows into a vacuum pump, disconnect or
otherwise isolate from the vacuum system. When capping
off ISO-KF style flanges use overpressure rings to
insure a leak free connection at positive line pressure.
Open DUTs flow control valve:
If the test system
contains a DUT that has flow control capability, it must
be slightly opened in order to allow pressure to pass
through. All that is necessary is a small flow to allow the
system to fully pressurize.
Display system pressure:
Monitor the system
pressure as measured by molbox by pressing the [P&T]
function until the pressure is displayed. Refer to molbox
Operation and Maintenance Manual for details.
Turn on gas supply:
Apply the supply pressure to the
pressure control regulator.
Slowly raise system pressure to desired test
pressure:
Rotating the regulator’s control knob
clockwise raises the outlet pressure. Rotate
counterclockwise to lower the outlet pressure. Increase
the system pressure to the desired DUT operating
pressure. Make final adjustments of control pressure in
the direction of increasing pressure in order to obtain the
most accurate and stable set point.
Adjust the regulator to obtain the desired operating
pressure.
Provide additional margin only if the final pressure
will be within the safe operating range of the molbox.
Regulator Adjustment
Once the regulator has been adjusted to the desired
pressure its adjusting stem should be locked down to
prevent further adjustments. This will help protect the
molbox RPTs from over-pressurization.
Remove regulator knob cover:
Use a small flat
screwdriver to remove the plastic cap on the top of the
regulator adjustment knob.
Loosen jamb nut:
Using the properly sized socket
wrench, loosen the jamb nut located on top of the
adjustment knob.
Adjust knob position:
Rotate the regulator adjustment
knob clockwise until it gently bottoms out against the
regulator body.
Tighten jamb nut:
Hold the adjustment knob in
position while using the socket wrench to tighten the
jamb nut against the top of the adjustment knob.
Retest system pressure:
Vent the system pressure.
Repeat system pressurization procedure to verify the
regulator pressure setting. Readjust if necessary.
Replace regulator knob cover:
Place the regulator
adjustment knob cover back on top of the knob and
gently snap back in place.
The following parts are included in the shipment:
DESCRIPTION
QTY
PART NO.
Regulator, pressure reducing
1
103232
Regulator bracket
1
123657
Adaptor, 8VCR x 8T
1
103233
Male nut, 8VCR
1
103029
Gasket, 8VCR
4
102923
Quick connect body
1
103234
Quick connect stem
1
103235
Union, 8VCR male
1
103236
SHC screw, #10-32 x 3/8
2
103277-Z
Split lock washer, #10
2
103021-Z
Flat washer, #10
2
103278-Z
SHC screw, M4 x 12
2
101016-Z
Flat washer, M4
2
100918-Z
Nut plate, 60 mm
1
123621
