2. INSTALLATION
Page 27
© 1998-2008 DH Instruments, a Fluke Company
Low torque manual rotation is all that should be required to fully seat the piston-cylinder
module into the PG7000 mounting post. Never force the piston-cylinder module into the
mounting post.
Always maintain PG7202 and PG7302 piston- cylinder modules vertical with the piston cap
up. Do not invert the assembly, as this might allow liquid to run up into the piston head and into
the adjustment mass and cap. Liquid contamination of the piston head and cap changes the mass of
the piston assembly and could lead to out of tolerance pressure definitions at low mass loads. If
liquid contaminates the adjustment mass and cap, disassemble the module and clean it (see
Sections 5.3.1, 5.3.4, 5.3.2.2).
2.3.3
SWITCHING A PG7202 BETWEEN GAS OPERATION AND
OIL OPERATION
PG7202 can be operated with gas as the pressurized medium using PC-7200 gas operated,
liquid lubricated modules or with oil as the pressurized medium using oil operated PC-7300
modules.
PC-7200 gas operated, liquid lubricated piston-cylinder modules can be operated in gas oil
filled with oil and operated in oil. Oil operation of PC-7202 modules is not recommended for
routine operation. It can be useful in very specific crossfloating circumstances, particularly when
establishing a calibration link between independent gas operated and oil operated piston gauges.
When switching PC-7200 module between oil and gas and oil operation, see Section 5.3.3 for
information on emptying excess oil from the module.
Switching a PG7202 from gas to oil operation
Only the high pressure PC-7300 oil modules may be used in the PG7202 platform
(PC-7300-1, -2, -5)
Disconnect the gas generation/control system from the TEST port.
Disconnect the
tube at the DH500 TEST port connection on the back of the PG7202. Loosely install a
DH500 plug in the TEST port.
Connect the oil generation/control system to the DRAIN port.
Connect a tube from
the oil generation/control system to the PG7202 DRAIN port and tighten it (torque DH500
glands to 15 Nm (12 ft.lb)).
Fill the PG7202 mounting post with oil.
Hand tighten the DH500 plug in the TEST
port. Use the oil generation/control component to fill the PG7202 mounting post with oil.
Fill to the edge of the second step in the mounting post. Place a paper towel under the
TEST port plug and loosen the DH500 plug allowing oil to run out until it is at the level of
the first step in the mounting post and there is no air in the run off oil. If there is still air in
the run off, repeat the operation. After filling the mounting post, tighten the DH500 plug
(torque DH500 glands to 15 Nm (12 ft.lb)).
Install a PC-7300 oil operated piston-cylinder module in the PG7202 platform.
Install the module and purge the air from underneath it (see Section2.3.2).
Operate with oil as the test medium.
The PG7202 can now be operated with oil as the
test medium.