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TANK TRUCK FUEL OIL DELIVERY OPERATION
Air Systems for Automatic Pressure and Speed Control
The pump is equipped with an adjustable spring actuated relief
valve. The spring bears against a piston. With the air pressure
on the piston, the valve controls pressure in the conventional
manner. When air pressure is removed, the relief valve opens
wide, reducing the system pressure.
The pilot valve senses flow. It closes when the nozzle closes
and removes air pressure from the pump air valve and the air
cylinder on the engine speed control.
When the nozzle is opened, the liquid flow actuates the pilot
valve. Air pressure on the air cylinder then speeds up the
engine and pump to a preset value and, by pressurizing the
pump air valve, increases the system pressure to obtain the
desired flow.
Closing the nozzle automatically reduces the engine and pump
speed to an idle, and reduces the system pressure, making the
hose easier to handle. The net effect also reduces wear and
tear on the equipment.
The nozzle may be partially closed to “top off” a tank in the
same manner as when a Blackmer pump with the standard
relief valve is used.
Rigidly mount the engine speed control air cylinder to prevent
variations in the speed control.
Figure 1 - Air System
Electric/Hydraulic Systems For Automatic Pressure And Speed Control
Explosive fluids will
cause severe personal
injury, death or major
property damage.
Failure to provide full flow discharge
piping, a properly grounded system and
system components will cause static
electricity, incendiary sparks and
ignition of explosive liquids.
Hazardous fluids can
cause fire, serious
personal injury or
property damage.
Failure to mount the 3-way pneumatic
valve away from heat, flame, sparks or
outside the engine compartment can
cause fire, personal injury or property
damage.
The pump is equipped with an adjustable spring relief valve.
The spring bears against the piston. With pump discharge
pressure on the piston, the valve controls pressure in the
conventional manner. When the pump discharge pressure is
removed, the relief valve opens wide, reducing the system
pressure.
The flow switch “senses” flow. With the pump running and the
nozzle open, liquid causes the electrical switch to close and
energize the solenoids. The solenoid on the carburetor or
injection pump causes the engine and pump to speed up to a
pre-set value. At the same time, the solenoid valve at the
pump uses the pump discharge pressure to change the bypass
setting at the pump, increasing the system pressure to obtain
the desired flow.
Closing the nozzle opens the flow switch, automatically reduces
the engine speed to an idle, and reduces the system pressure,
making the hose easier to handle. The net effect also reduces
wear and tear on the equipment. The nozzle may be partially
closed to “top off” a tank in the same manner as when a
Blackmer pump with the standard relief valve is used.
Rigidly mount the engine speed control solenoid to prevent
variations of the engine speed.
Figure 2 – Electric / Hydraulic System
