PLATE-WEAR 4871664 - Caterpillar

Level Vent Control Assembly (LVCA)
Illustration 4 g03780399
Level vent control assembly (LVCA)
The level control shutoff and fuel tank venting action is built into a single housing. A float is used to actuate the level control valve. The vent only allows for positive venting (fuel tank to atmosphere). A separate vacuum vent is required for venting atmosphere into the tank via a vented fuel cap or separate breather.Inlet Shutoff Valve
Illustration 5 g03780417
Inlet shutoff valve
Illustration 6 g03780419
Typical view of a single signal line and inlet valve arrangement with remote fast fill provision.
The inlet shutoff valve controls fuel flow into the tank and is located inside the fuel tank after the receiver.Signal Line/Hose
Illustration 7 g03787480The signal line/hose connects the inlet valve to the level vent control assembly (LVCA). The hose transmits a signal to the shutoff valve to close, once the tank is full.Shuttle Valve Assembly (Dual Fill Receptacle Option)
Illustration 8 g03780429
Shuttle valve assembly
Illustration 9 g03780427
Dual signal line and inlet valve arrangement with remote fast fill provision.
The shuttle valve assembly is utilized when the dual fuel fill receptacle option is attached. The shuttle valve blocks fuel flow to the inlet valve assembly that is not being utilized during the fill cycle.Diesel Fuel Fill Nozzle
Illustration 10 g03780441
Diesel fuel fill nozzle
The diesel fuel fill nozzle is mounted to the customers fuel supply apparatus. The nozzle connects at the receiver assembly to fill the fuel tank. The nozzle provides the automatic shutoff feature during complete tank fill.Note: The fuel nozzle should have a shutoff pressure between 48 kPa (7 psi) and 62 kPa (9 psi).Theory of System Operation
The inlet valve serves as a shutoff valve at the end of a fuel tank fill, and as a check valve to prevent back flow through the tank inlet. The inlet shutoff valve consists of a plastic piston type valve with a rubber seal to seal against the valve seat. On the tank side of the valve (the backside of the piston) is a pressure chamber sealed from the tank with a rubber diaphragm. A spring inside the chamber pushes down on the valve to hold the valve in the normally closed position.
Illustration 11 g03780460
(A) Vacuum vented fuel cap
(B) Vent / Level control unit
(C) Float in down / open position
(D) Fuel flow with float in open / down position
(E) Fuel level
(F) Signal line
(G) Inlet valve in open position
(H) Inlet fuel flow
(J) Receiver As fuel flows into the valve, the valve and diaphragm are pushed open against the spring force, and fuel is pushed radially outward from the valve and into the tank. During filling (refer to Illustration 11), a small amount of fuel passes through an orifice on the inlet side of the valve. The fuel flowing through the orifice fills the inside of the diaphragm, and then continues to flow up a signal line and out into the tank.
Illustration 12 g03780610
(F) Signal line
(K) Float in up / closed position
(L) Inlet valve closed
(M) Additional fuel cannot enter the tank with the valve closed When the fuel level reaches the full tank level, the float actuates and closes