Load Frame
The load frame consists of:
1. A pressure vessel.
2. Three ISCO pumps, which control:
axial, confining and pore pressure.
3. Two control panels.
4. Validyne portable acquisition package.
5. Computer.
1. Pressure
vessel:
The pressure vessel is the place where the sample of study is pressurized. There are 4 sections on the pressure head, each
of them are labeled as seen in appendix 1.
Sections one, two and three are electrical leads for strain
gauges, transducers, etc. while section four is for thermocouples and fluid
inputs.
2. ISCO
pumps:
Consists of a syringe pump, filled with a certain fluid, generally
oil. The ISCO pumps have a maximum pressure
limit:
Confining
pressure: 20,000 psi
Axial and
pore pressure: 10,000psi
3. Control
panels:
The first control panel controls the first three sections of the
pressure head.
The second control panel consists of a set of switches and valves
that control the flow of fluids in and out of the pressure vessel for axial and
confining pressure. The diagram is shown
on appendix 2.
Switches: open horizontal. Close down.
Valves
and wheels: open
counterclockwise. Close clockwise. It is
not necessary to open completely, three turns is sufficient.
4. Validyne portable acquisition package:
The Validyne
module case currently has five available SG297A strain gage amplifiers (refer
to manual if necessary). These ALWAYS
need to be calibrated with a shunt resistance before running an experiment. The
module case is connected to the computer through a USB port, which allows data
collection in the computer with Tracer DAQ software.
How to connect the sample on the pressure head
Put sample in the
pressure vessel. Connect wires of the
sample in the different sections, according to the experiment.
Lower the upper
part of the pressure vessel with the control. Be careful not to ruin the sample
or any of the cables!
When it is finally
down, remove the aluminum rod to the left.
Rotate the upper part of the pressure vessel clockwise for securing it.
For security
reasons, lower the plastic shield
Applying confining pressure to the vessel:
Open valve 1 to
fill up the pressure vessel with oil.
Open valve 10.
Open switch 5 to
vent the system.
Open knob 2 to put
air pressure into the oil reservoir.
Turn valve 8
towards pressure.
Once the glass tube
fills up with oil, close valve 10 so that the trap does not fill up. We know
that the pressure vessel is full when the tube has oil in it.
Close valves 1,
10, 5 and 2.
Vent the oil
reservoir, by turning valve 8. Close it
when the pressure is vented.
Set ISCO pump to a
pressure of 120 psi, approximately.
Press A to enter
pressure value. Enter numerical value.
Press enter.
Open valve 14, to pressurize
the vessel.
The confining
pressure is set.
After using, lower
the pressure of the system in the same way, using ISCO pump.
Close valve 14.
Applying axial pressure to the vessel:
Open valve 15.
Set ISCO pump to a
low pressure (10-20 psi).
Press A for
entering pressure value.
NOTE: Axial pressure should ALWAYS be higher than the confining
pressure.
Enter numerical
value.
Press enter. Press run.
The axial pressure
is set.
After using, lower
the pressure of the system to 10-20 psi in the same way, using ISCO pump.
Close valve 15.
Applying pore pressure to the sample:
Open valves 16 and
17.
For one pore fluid
line: open valve 18 and 20
For two pore fluid
lines: open valves 18, 19 and 20.
Apply the desired
pore pressure from the ISCO pump.
NOTE: Pore pressure should NEVER be higher than the confining
pressure.
To remove pore pressure:
Lower the pressure
of the system to 10-20 psi in the same way, using ISCO pump.
Close valves 16 to
20.
Emptying the pressure vessel-filling up the oil reservoir:
Open valve 1 to
fill up the oil reservoir.
Open valve 10.
Open switch 2, 3
and 4.
After the oil
reservoir starts bubbling, close valve 2.
Vent system with
valve 8.
After the oil
reservoir stops bubbling, close valves 1 and 10.
Close switches 3
and 4.
Opening the pressure vessel
Pull up the plastic shield.
Turn the upper part of the vessel counter clockwise
until the marks on the right line up.
Use the control for lifting the vessel. After lifting a bit, put the
aluminum rod on the left slot of the pressure vessel. Lift up the vessel
completely.
Clean the oil out of the whole system!
Refilling the main oil reservoir:
First, make sure the reservoir is vented! Make sure knob 2 is closed and valve 8 is
pointing towards “Vent”.
Open valve 22 and pour oil into the reservoir.
Failure mode analysis
Load frame
Appendix 1
Pressure head lines
Appendix 2
Legend appendix II
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