MTS Model 286-30 Pore Pressure Intensifier - Manual (Page 36)

286.30 Pressure Intensifier 36
Operating Procedures
Operation
Procedure:
1. At the PPI’s control panel, open the Pore Fluid Input and Pore Fluid
Output valves.
2. Set up the PPI’s electronic controller for operation in the pressure control
mode.
Hydraulic power will be applied during this procedure. Conditions that can
be hazardous to life and equipment can exist on all systems or equipment
that are connected to the same hydraulic power source.
Before turning on hydraulic power, make sure that all systems or equipment that
use the same hydraulic power source are in an appropriate condition before you
turn on hydraulic power.
Make certain no one is performing work on other systems or equipment that share
the same hydraulic power source as the PPI. If people are working on other
systems or equipment, inform them that you intend to turn on hydraulic power.
Inform other people in the vicinity that you are about to turn on hydraulic power.
3. At the PPI’s controller equipment, turn on high hydraulic pressure.
Note In the following steps fluid will flow into the specimen, forcing air out to
the reservoir.
On later PPI versions, the line from the Pore Fluid Output control expels
air/fluid into the reservoir from above the fluid level -- watch for bubble-
free fluid to flow into the reservoir. On earlier PPI versions the line from
the Pore Fluid Output control enters into the bottom of the reservoir --
watch for the bubble stream to stop flowing.
4. At the pressure controller, apply a positive command that is sufficient to
cause pore fluid to flow. This is done by turning the Set Point control on the
controller.
(Before fluid can be seen flowing into the reservoir, you can determine that
it is flowing into the triaxial cell by watching the displacement variable, as
displayed on the controller equipment. The rate of flow is proportional to
the rate of change of the displacement variable.)
5. Watch for air bubbles entering the reservoir (see the note above.) After
bubbles are no longer observed, close the Pore Fluid Output valve.
After the Pore Fluid Output valve is closed, the pore pressure system will
remain under closed-loop control at a pressure level corresponding to the
level of the applied pressure command.
WARNING