1-26
American-Lincoln
3366XP
LP FUEL TANKS
Standard D.O.T. LP fuel tank sizes have 14, 20, 33.5, and 43.5 lb. capacities. The liquid volume permitted in
these containers is less than the total volume of the cylinder, to provide for expansion of the LP fuel should the
temperature increase a normal amount. Excessive heat may cause the fuel to expand too much, causing the
safety relief valve to vent some LP fuel, relieving internal tank pressure.
Each tank is marked showing the type of construction (liquid or vapor), the manufacturer, the date of manufac-
ture, the capacity, the weight, and the date of requalification. D.O.T. LP fuel tanks must be requalified
(checked) periodically. This requalification must be recorded and maintained for the life of the container. LP
fuel tanks are equipped with the following approved valves and fittings.
1.
Safety Relief Valve - This is a spring-loaded valve that relieves excessive pressures which might develop
in the tank due to unusual conditions.
2.
Liquid Service Valve - Liquid is withdrawn from the tank through this valve. The LP tank may be filled
through this valve if the tank is not equipped with a filler valve.
a. Excess Flow Valve - This valve is part of the liquid service valve. It is mounted inside the tank and
prevents LP fuel from leaving the LP tank in the event of accidental breakage of external fittings or
hoses. It permits flow in either direction, but stops outward flow if that flow becomes excessive.
3.
Filler Valve - This valve is optional. If this valve is not present, the tank is filled through the service valve.
4.
Liquid Level Gauge - This gauge is optional.
LP LIQUID WITHDRAWAL SYSTEM
The liquid withdrawal LP fuel systems are made up of six components. Those components are: the LP tank,
pressure relief valve, fuel filter lock, vaporizer-regulator and the carburetor. See Figure 16.
The liquid LP fuel flows from the LP tank, under its own pressure, to the pressure relief valve. This valve is
normally closed, preventing LP fuel from escaping into the atmosphere. This LP gas is then piped to the LP
fuel filter lock. The fuel filter lock removes unwanted tank cable and deposits from the LP gas. The vaporizer
converts the liquid LP fuel into a gaseous LP fuel. The gaseous LP fuel is sent to the primary regulator. The
primary regulator reduces the pressure of the LP fuel and makes the flow more constant. The secondary
regulator reduces LP gas pressure to the level required by the carburetor. From the secondary regulator, it is
piped to the carburetor where the LP fuel is finally metered into the air flow which is sent to the combustion
chamber.
LP POWERED MACHINES
FUELLOCK/FILTER
TANK
RELIEF
VALVE
TANK
VALVE
LPG
FUEL
TANK
PRESSURE
RELIEF
VALVE
REGULATOR/VAPORIZER
CARBURETOR
P4502B/9811
RELIEF VALVE
SIGHT GAUGE
VAPOR LINE
OUTAGE ADAPTER
LIQUID LINE
P4502b
FIGURE 16
P4502-1
FIGURE17
