TUBE GP-HYDRAULIC 3598683 - Caterpillar

Illustration 1 g01668376
Variable pitch fan system (1) Fan hub (2) Valve (3) Air pump (A) Filtered airThe optional variable pitch fan periodically changes the pitch of the fan blades in order to clear the cooling system of debris. Air pump (3) draws filtered air from the engine air intake. The air pump compresses the air to 760 kPa (110 psi). Valve (2) allows the compressed air to flow to fan hub (1). The compressed air moves a piston inside the fan hub. The movement of the piston causes the fan blades to swivel by 90 degrees. This reverses the flow of air through the cooling system.In this position, the fan blades will purge the cooling system of debris. The purge lasts for 20 seconds. When the purge ends, the pump and the valve shut off. This allows the pressure in the fan hub to vent through a vent port on the valve. The fan blades will return to the normal position. The fan will continue to operate in normal mode until the next purge. The default setting for the duration between two purges is 20 minutes. This time can be adjusted from 3 minutes to 60 minutes by using Electronic Technician. Then, another purge cycle will be initiated.The purge cycle may be initiated manually by a switch that is inside the cab. Activating the switch will begin a purge cycle. The minimum time between purge cycles is three minutes. If the switch is activated within three minutes of the end of the previous cycle, the purge cycle will be delayed until the end of the three minutes. Automatic operation will resume after the manual purge is complete.