- The vented cap (1)
- The vent for the tank (2)
- The float (3)
- The signal line (4)
- The shutoff valve (5)
When float (3) is in the DOWN position, fuel enters the tank from the receiver for the nozzle and flows through the open shutoff valve (5). A small amount of fuel is purged through a flexible stainless steel braided signal line (4) to float (3). During filling, the fuel that is purged spills freely into the tank from float (3), and air is displaced out of the tank through relief valve (2). Air vent (2) will not open immediately after the fuel flow begins but only after a certain amount of air pressure has built up in the tank. Larger tanks may require significant filling before the vent opens.
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| Illustration 1 | g01273310 |
As the tank fills, the fuel level begins to lift float (3). When float (3) rises, the float blocks signal line (4) and the flow of fuel that is purged. As signal line (4) builds pressure inlet valve (5) is closed, and the flow of fuel to the tank is blocked. The fuel nozzle disengages due to back pressure. When float (3) is in the up position, shutoff valve (5) is hydraulically locked and fuel can not be pumped into the tank.
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| Illustration 2 | g01271188 |
163-5455 Valve As and 188-5095 Vent Assembly operation (A) Float (3) in the open position (B) Surge suppressor "(Yellow)" (C) Diaphragm (D) Small orifice (E) Valve housing (F) Bottom of fuel tank (G) Signal Line "Red" indicates the circuit for the signal. (H) The flow for the signal line is unrestricted until the valve for the float closes. (J) Fuel inlet | |
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| Illustration 3 | g01271417 |
188-5095 Vent Assembly (FF) with the vent closed. 188-5095 Vent Assembly (GG) with the vent open. (AA) orifice for the vent valve (BB) Spring for the vent (CC) Vent hole (DD) Diaphragm (EE) Vent Valve (FF) 188-5095 Vent Assembly with the vent closed. (GG) 188-5095 Vent Assembly with the vent open. (HH) Path for air that is displaced by incoming fuel | |