Humboldt HM-4165 3-Cell Manual Control Panel - Manual (Page 6)

4
AIR/WATER CONTROL VALVES
There are several control valves on the panel for on/off operation of the
air and water control.
There are two valves under the De-Airing Tank heading (Figure 6). These
valves control flow of water to and from the de-airing tank and air or
vacuum to the tank. The water flow valve either allows tap water to fill
the tank or allows the tank to be drained for cleaning and maintenance.
The other valve is for the application of vacuum to the de-airing tank to
remove air from the water in the tank and it also allows compressed air
to be pumped into the tank to assist in draining the water from the tank.
The small auxiliary regulator controls the amount of pressure to assist in
draining the water from the de-airing tank. Set the desired pressure by
turning the knob on the auxiliary regulator in the clockwise direction.
NOTE: These valves must be in the off position during a test.
There are three valves under the AIR CONNECTION heading (Figure
7) on the front of the panel (one valve per triaxial cell). These valves
connect the digital display to the corresponding regulators so that the
pressure for any individual air line can be displayed one at a time.
When the valve is in the off position, the pressure is still controlled by
the regulator. NOTE: When the pressure is displayed for one of the cell
air connections, the other cell air valves must be in the OFF position or
else the incorrect pressure will be displayed.
There are six valves under the WATER CONNECTION heading. There
are two valves for each triaxial cell apparatus which are used to control
the flow of tap water to the cell and to the corresponding bladder
cylinder and also de-aerated water to the Auto Volume Change and to
the other bladder cylinder in the apparatus (Figure 8). When the valve
is in the FILL position, water flows to the cell and bladder cylinder at the
same time, or to the second bladder cylinder and to the Auto Volume
Change at the same time. The CELL valve has drain position which
allows water to be drained from the cell. NOTE: These valves should be
in the off position during a test. The valve is in the off position when the
knob is pointed to the left.
PRESSURE GAUGES
There are two pressure gauges on the panel. The gauge at the upper
left side is used to monitor the pressure regulated by the main pressure
input regulator. It is a mechanical gauge and requires no electrical
source. The other gauge has a digital display and is used to monitor the
air pressure in the bladder cylinders which control the pressure in the
cell and the back pressure in the sample. To operate this gauge, it must
first be connected to an AC power source. It has an On/Off button on
the left side of the display.