The pressure switch operates only when the motor
controller switch is set at the AUTOMATIC position.
The caution plate (8) is located next to the vent valve
(2). It cautions all concerned to keep the vent valve
open at all times except when charging the
accumulator, and contains instructions for closing the
vent valve when charging the accumulator.
A gauge valve (3) is furnished to maintain pressure
in the accumulator when it is necessary to remove the
pressure gauge (6). The air-charging valve (5) regulates
the charging flow. The air supply valve (4) controls the
flow intake of air to the control panel and accumulator.
The operating instruction plate (10) contains basic
operating instructions and a piping schematic.
The motor controller regulates the starting and
stopping of the pump motor in conjunction with the
pressure-sensing switch. The controller, operating
magnetically, provides a switch control for OFF,
AUTOMATIC, or RUN positions. The OFF position is
used when the power package is secured. The
AUTOMATIC position is used when the power
package is to be operated, and the RUN position is used
when it is necessary to bypass the pressure-sensing
switch. Protective features of the controller include
pilot circuit and motor overload protection and
undervoltage release. A white light is mounted on the
controller to indicate when power is available. When
the switch is in the OFF position, the circuits from the
controller to the motor and the pressure-sensing switch
remain open, or dead. In the AUTOMATIC position,
the motor starts when the contacts are closed in the
pressure-sensing switch, and the motor stops when the
contacts open. The RUN position is spring returned,
and the motor runs only as long as the switch is
In the piping system, manual valves are placed in
the lines to provide for operating and standby
conditions and for maintenance. Each valve is tagged
with a nameplate giving its number and normal
cellaneous equipment includes a check valve, fluid
strainer, hydraulic pressure relief valve, and an air
safety head. The check valve between the accumulator
and pump prevents fluid pressure from backing up to
the pump. The fluid strainer in the line between the
gravity tank and the pump removes foreign matter
before it enters the pump. The hydraulic relief valve
connected to the line between the check valve and
pump provides for pressure relief. The hydraulic relief
valve is adjusted to crack open at 1,600 psi (minimum)
and open full at 1,750 psi. This line is equipped with a
liquid sight indicator for visual checking of fluid flow,
which would indicate an open relief valve. The air
safety head, which ruptures at approximately 2,000 psi,
is connected to the air line between the accumulator and
control panel. It acts as a safety to prevent charging the
accumulator and related components above their design
limits. Two breather vents at the top of the gravity tank
provide for passage of air out of or into the tank as the
liquid level rises or lowers. A screen in the breather vent
removes any foreign matter from incoming air.
During normal operations the system is put in the
READY condition. The power package, which is
located below deck and includes an accumulator and
gravity tank, is to be placed in a READY condition as
Place accumulator pressure at 1,500 psi.
Fill accumulator and gravity tank liquid to
Open or close proper valves.
Place motor controller switch on AUTOMATIC.
Check controls for proper operation.
Inspect barricade-tensioning pendants for fray-
As shown in figure 3-46, after the latch at the top of
the stanchion is released, the deckedge control valve
lever is placed in the Raise position (No. 1), and the
stanchions will raise simultaneously. Raising opera-
tions may be stopped and stanchions held in any
position by placing the deckedge control valve lever in
the Neutral position (No. 2).
To lower the stanchions, place the deckedge control
valve lever in the Lower position (No. 3). Stanchions
will lower simultaneously. Lowering operations may be
stopped and stanchions held in any position by placing
the deckedge control valve lever in mid-position
The deckedge control valve lever in mid-position
(No. 2) is the standby position. It blocks all valve ports,
and any passage of fluid is stopped when the valve is in
this position. This position should be used to stop
stanchions during raising or lowering or to hold the
stanchions either up or down.